Готові списки джерел за темами / GeTe alloys

Добірка наукової літератури з теми "GeTe alloys"

Автор: Grafiati

Опубліковано: 4 травня 2024

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Статті в журналах з теми "GeTe alloys"

Cao, Yiqi, Zhigang Li, Jianbo Wu, Xiaohua Huang, and Shengnan Zhang. "Electrical Properties of GeTe-based Ternary Alloys." Journal of Wuhan University of Technology-Mater. Sci. Ed. 33, no. 2 (April 2018): 472–75. http://dx.doi.org/10.1007/s11595-018-1847-2.

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Bu, Zhonglin, Xinyue Zhang, Bing Shan, Jing Tang, Hongxia Liu, Zhiwei Chen, Siqi Lin, Wen Li, and Yanzhong Pei. "Realizing a 14% single-leg thermoelectric efficiency in GeTe alloys." Science Advances 7, no. 19 (May 2021): eabf2738. http://dx.doi.org/10.1126/sciadv.abf2738.

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GeTe alloys have recently attracted wide attention as efficient thermoelectrics. In this work, a single-leg thermoelectric device with a conversion efficiency as high as 14% under a temperature gradient of 440 K was fabricated on the basis of GeTe-Cu2Te-PbSe alloys, which show a peak thermoelectric figure of merit (zT) > 2.5 and an average zT of 1.8 within working temperatures. The high performance of the material is electronically attributed to the carrier concentration optimization and thermally due to the strengthened phonon scattering, the effects of which all originate from the defects in the alloys. A design of Ag/SnTe/GeTe contact successfully enables both a prevention of chemical diffusion and an interfacial contact resistivity of 8 microhm·cm2 for the realization of highly efficient devices with a good service stability/durability. Not only the material’s high performance but also the device’s high efficiency demonstrated the extraordinariness of GeTe alloys for efficient thermoelectric waste-heat recovery.

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Zhang, Xinyue, Juan Li, Xiao Wang, Zhiwei Chen, Jianjun Mao, Yue Chen, and Yanzhong Pei. "Vacancy Manipulation for Thermoelectric Enhancements in GeTe Alloys." Journal of the American Chemical Society 140, no. 46 (September 28, 2018): 15883–88. http://dx.doi.org/10.1021/jacs.8b09375.

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Srinivasan, Bhuvanesh, David Berthebaud, and Takao Mori. "Is LiI a Potential Dopant Candidate to Enhance the Thermoelectric Performance in Sb-Free GeTe Systems? A Prelusive Study." Energies 13, no. 3 (February 3, 2020): 643. http://dx.doi.org/10.3390/en13030643.

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As a workable substitute for toxic PbTe-based thermoelectrics, GeTe-based materials are emanating as reliable alternatives. To assess the suitability of LiI as a dopant in thermoelectric GeTe, a prelusive study of thermoelectric properties of GeTe1−xLiIx (x = 0–0.02) alloys processed by Spark Plasma Sintering (SPS) are presented in this short communication. A maximum thermoelectric figure of merit, zT ~ 1.2, was attained at 773 K for 2 mol% LiI-doped GeTe composition, thanks to the combined benefits of a noted reduction in the thermal conductivity and a marginally improved power factor. The scattering of heat carrying phonons due to the presumable formation of Li-induced “pseudo-vacancies” and nano-precipitates contributed to the conspicuous suppression of lattice thermal conductivity, and consequently boosted the zT of the Sb-free (GeTe)0.98(LiI)0.02 sample when compared to that of pristine GeTe and Sb-rich (GeTe)x(LiSbTe2)2 compounds that were reported earlier.

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Krbal, Milos, Alexander V. Kolobov, Paul Fons, Kiyofumi Nitta, Tomoya Uruga, and Junji Tominaga. "Investigation of the oxidation process in GeTe-based phase change alloy using Ge K-edge XANES spectroscopy." Pure and Applied Chemistry 91, no. 11 (November 26, 2019): 1769–75. http://dx.doi.org/10.1515/pac-2018-1229.

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Abstract In this work, we clearly demonstrate the efficacy of using XANES spectroscopy in conjunction with a Pilatus detector as a sensitive tool to allow the study of the oxidation process in GeTe alloys via depth profile analysis. On the basis of Ge K-edge XANES spectra, it was found that GeTe alloys do not oxidize readily after an initial native surface oxidation that occurs upon exposure to oxygen in the air at the elevated temperatures, 100 °C and 330 °C. We demonstrate that amorphous GeTe possesses a higher predisposition to oxidation than crystalline GeTe when exposed to the air at temperature of 100 °C. When the temperature is set to 330 °C in an air ambient, we show that the amorphous to crystal phase transition affects the oxidation process more significantly than the simple annealing of crystalline GeTe. We suggest that the higher tendency of GeTe films to oxidize during the phase transition is a consequence of the breaking of Ge–Ge bonds in the presence of oxygen atoms which subsequently leads to the extra formation of Ge–O bonds during crystallization.

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Ebrahimi, F., D. Liu, H. Engelhardt, and M. Rettenmayr. "Morphology Control During Heat Treatment of GeTe-PbTe Alloys." Practical Metallography 57, no. 4 (April 15, 2020): 250–59. http://dx.doi.org/10.3139/147.110605.

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Dong, Yongkwan, Abds-Sami Malik, and Francis J. DiSalvo. "High Power Factor of HPHT-Sintered GeTe-AgSbTe2 Alloys." Journal of Electronic Materials 40, no. 1 (October 1, 2010): 17–24. http://dx.doi.org/10.1007/s11664-010-1383-1.

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Mukhtarova, Ziyafat. "Фазовые равновесия в системе Sm2Te3–GeTe". Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 21, № 2 (15 червня 2019): 328–33. http://dx.doi.org/10.17308/kcmf.2019.21/770.

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Методами физико-химического анализа – дифференциально-термическим, высокотемпературным дифференциально-термическим, рентгенофазовым, микроструктурным, а также измерением микротвердости изучена система Sm2Te3–GeTe, которая является квазибинарным сечением тройной системы Ge–Sm–Te. При соотношении исходных теллуридов 1:1 (50 мол. %) и температуре 1100 К по перитектической реакции ж+Sm2Te3→ GeSm2Te4 образуется тройное соединение GeSm2Te4. Образцы системы, богатые GeTe, представляют собой компактные слитки блестяще-серого цвета, а сплавы, бо-гатые Sm2Te3 – спек черного цвета. Ликвидус системы Sm2Te3–GeTe состоит из трех ветвей: Sm2Te3, GeSm2Te4 и a-твердых растворов на основе GeTe. Рентгенофазовый анализ закристаллизованных образцов показал, что набор рентгеновских отражений соответствует фазам Sm2Te3, GeSm2Te4 и a-твердых растворов на основе GeTe. Установлено образование инконгруэнтно плавящегося соединения состава GeSm2Te4, которое может использоваться как термоэлектрический материал. На основе GeTe образуется узкая область твердого раствора REFERENCES Kohri H., Shiota , Kato M., Ohsugi J., Goto T. Synthesis and Thermolelectric Properties of Bi2Te3–GeTe Pseudo Binary System. Advances in Science and Technology, 2006, v. 46, pp. 168-173. https://doi.org/10.4028/www.scientifi c.net/ST.46.168 Gelbstein Y., Dado B., Ben-Yehuda O., Sadia Y., Dashevsky Z. and Dariel M. P. Highly effi cient Ge-Rich GexPb1-x Te thermoelectric alloys. Journal of Electronic Materials, 2010, v. 39(9), pp. 2049–2052. https://doi.org/10.1007/s11664-009-1012-z Gelbstein Y., Davidow J., Girard S.N., Chung D. Y. and Kanatzidis M. Controlling Metallurgical Phase Separation Reactions of the Ge0.87 Pb0.13Te Alloy for High Thermoelectric Performance. Advanced Energy Materials, 2013, v. 3, pp. 815–820. https://doi.org/10.1002/aenm.201200970 Gelbstein Y., Dashevsky Z. and Dariel M. P. Highly efficient bismuth telluride doped p-type Pb0.13Ge0.87Te for thermoelectric applications. Physical Status Solidi, 2007, v. 1(6), pp. 232–234. https://doi.org/10.1002/pssr.200701160 Gelbstein Y., Ben-Yehuda O., Dashevsky Z. and Dariel M. P. Phase transitions of p-type (Pb,Sn,Ge)Tebased alloys for thermoelectric applica tions. Journal of Crystal Growth, 2009, v. 311(18), pp. 4289–4292. https://doi.org/10.1007/s11664-008-0652-8 Gelbstein Y., Ben-Yehuda O., Pinhas E., et al. Thermoelectric properties of (Pb,Sn,Ge) Te-based alloys. Journal of Electronic Materials, 2009, v. 38(7), 1478–1482. https://doi.org/10.1007/s11664-008-0652-8 Li J., Chen Z., Zhang X., Sun Y., Yang J., Pei Y. Electronic origin of the high thermo- electric performance of GeTe among the p-type group IV monotellurides. NPG Asia Materials, 2017, v. 9, p. 353. https://doi.org/10.1038/am.2017.8 Sante D. Di., Barone P., Bertacco R., Picozzi S. Electric control of the giant rashba effect in bulk GeTe. Advanced materials, 2013, v. 25(27), pp. 3625–3626. https://doi.org/10.1002/adma.201203199 Li J., Zhang X., Lin S., Chen Z., Pei Y. Realizing the high thermoelectric performance of GeTe by Sbdoping and Se-alloying. Mater., 2017, v. 29(2), pp. 605–611. https://doi.org/10.1021/acs.chemmater.6b04066 Abrikosov N. Kh., Shelimova L. B. Poluprovodnikovye materialy na osnove soedineniy AIV BVI. [Semiconductor materials based on compounds АIV В]. Moscow, Nauka Publ., 1975, 195 p. (in Russ.) Korzhuev M. A. Vliyaniye legirovaniya na parametric of GeTe. Series 6. [Effect of doping on GeTe Series 6]. Moscow, 1983, no. 6 (179), pp. 33–36. (in Russ.) Okoye I. Electronic and optical properties of SnTe and GeTe. Journal of Physics: Condensed Matter, 2002, 14(36), pp. 8625–8637. https://doi.org/10.1088/0953-8984/14/36/318 Gelbstein Y., Rosenberg Y., Sadia Y. and Dariel M. P. Thermoelectric properties evolution of spark plasma sintered (Ge0.6Pb0.3Sn0.1)Te following a spinodal decomposition. Journal of Physical Chemistry, 2010, v. 114(30), pp. 13126–13131. https://doi.org/10.1021/jp103697s Rosenthal T., Schneider N., Stiewe C., Düblinger M., Oeckler O. Real Structure and thermoelectric properties of GeTe-rich germanium antimony tellurides. Mater., 2011, v. 23(19), pp. 4349–4356. https://doi.org/10.1021/cm201717z Li J., Chen Z., Zhang X., Yu H., Wu Z., Xie H., Chen Y., Pei Y. Simultaneous optimization of carrier concentration and alloy scattering for ultrahigh. Mater., 2017, v. 4(12), p. 341. https://doi.org/10.1002/advs.201700341 Bletskan D. I. Phase equilibrium in the system AIV-BVI-part II: systems germanium-chalcogen. Journal of Ovonic Research, 2005, v. 1(5), p. 53–60. Li S. P., Li J. Q., Wang Q. B., Wang L., Liu F. S., Ao W. Q. Synthesis and thermoelectric properties of the (GeTe)1-x(PbTe)x alloys. Solid State Sciences, 2011, v. 13(2), pp. 399–403. https://doi.org/10.1016/j.solidstatesciences. 2010.11.045 Gelbstein Y., Dado B., Ben-Yehuda O., Sadia Y., Dashevsky Z., Dariel M. P. High thermoelectric fi gure of merit and nanostructuring in bulk p-type Gex(SnyPb1–y)1–x Te alloys following a spinodal decomposition reaction. Chemistry of Materials, 2010, v. 22(3), pp. 1054–1058. https://doi.org/10.1021/cm902009t Yarembash E. I., Eliseev A. A. Khal’kogenidy redkozemel’nykh elementov: sintez i kristallokhimiya [Chalcogenides of rare-earth elements: synthesis and crystal chemistry]. Moscow, Nauka Publ., 1975, p. 258. (in Russ.) Mukhtarova Z. M., Bakhtiyarly I. B., Azhdarova D. S. Politermicheskoye secheniye Ge0.80 Te0.20–Sm0.80 Te0.20. khim. zhurn., 2010, no. 4, pp. 144–146. Mukhtarova Z. M., Bakhtiyarly I. B., Azhdarova D. S. Issledovaniye politermicheskogo secheniye Ge0.84Te0.16–Sm5Ge2Te7 v troynoy sisteme Ge–Te–Sm. Aze-rb. khim. zhurn., 2011, no. 4, pp. 57–59.

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Herrmann, Markus Guido, Ralf Peter Stoffel, Michael Küpers, Mohammed Ait Haddouch, Andreas Eich, Konstantin Glazyrin, Andrzej Grzechnik, Richard Dronskowski, and Karen Friese. "New insights on the GeSe x Te1−x phase diagram from theory and experiment." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 75, no. 2 (March 27, 2019): 246–56. http://dx.doi.org/10.1107/s2052520619001847.

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The high-pressure and low-temperature behaviour of the GeSe x Te1−x system (x = 0, 0.2, 0.5, 0.75, 1) was studied using a combination of powder diffraction measurements and first-principles calculations. Compounds in the stability field of the GeTe structure type (x = 0, 0.2, 0.5) follow the high-pressure transition pathway: GeTe-I (R3m) → GeTe-II (f.c.c.) → GeTe-III (Pnma). The newly determined GeTe-III structure is isostructural to β-GeSe, a high-pressure and high-temperature polymorph of GeSe. Pressure-dependent formation enthalpies and stability regimes of the GeSe x Te1−x polymorphs were studied by DFT calculations. Hexagonal Ge4Se3Te is stable up to at least 25 GPa. Significant differences in the high-pressure and low-temperature behaviour of the GeTe-type structures and the hexagonal phase are highlighted. The role of Ge...Ge interactions is elucidated using the crystal orbital Hamilton population method. Finally, a sketch of the high-pressure phase diagram of the system is provided.

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Wang, Longquan, Junqin Li, Chunxiao Zhang, Teng Ding, Yucheng Xie, Yu Li, Fusheng Liu, Weiqin Ao, and Chaohua Zhang. "Discovery of low-temperature GeTe-based thermoelectric alloys with high performance competing with Bi2Te3." Journal of Materials Chemistry A 8, no. 4 (2020): 1660–67. http://dx.doi.org/10.1039/c9ta11901a.

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Більше джерел

Дисертації з теми "GeTe alloys"

Bragaglia, Valeria. "Epitaxial Growth and Ultrafast Dynamics of GeSbTe Alloys and GeTe/Sb2Te3 Superlattices." Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18406.

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In dieser Arbeit wird das Wachstum von dünnen quasi-kristallinen Ge-Sb-Te (GST) Schichten mittels Molekularstrahlepitaxie demonstriert, die zu einer geordneten Konfiguration von intrinsischen Kristallgitterfehlstellen führen. Es wird gezeigt, wie es eine Strukturanalyse basierend auf Röntgenstrahlbeugungssimulationen, Dichtefunktionaltheorie und Transmissionselektronenmikroskopie ermöglicht, eine eindeutige Beurteilung der Kristallgitterlückenanordnung in den GST-Proben vorzunehmen. Das Verständnis für die Ordnungsprozesse der Gitterfehlstellen erlaubt eine gezielte Einstellung des Ordnungsgrades selbst, der mit der Zusammensetzung und der Kristallphase des Materials in Zusammenhang steht. Auf dieser Basis wurde ein Phasendiagramm mit verschiedenen Wachstumsfenstern für GST erstellt. Des Weiteren wird gezeigt, dass man eine hohe Ordnung der Gitterfehlstellen in GST auch durch Ausheizprozesse und anhand von Femtosekunden-gepulster Laserkristallisation von amorphem Material erhält, das zuvor auf einem als Kristallisationsgrundlage dienenden Substrat abgeschiedenen wurde. Diese Erkenntnis ist bemerkenswert, da sie zeigt, dass sich kristalline GST Schichten mit geordneten Kristallgitterlücken durch verschiedene Herstellungsprozesse realisieren lassen. Darüber hinaus wurde das Wachstum von GeTe/Sb2Te3 Übergittern durchgeführt, deren Struktur die von GST mit geordneten Gitterfehlstellen widerspiegelt. Die Möglichkeit den Grad der Gitterfehlstellenordung in GST gezielt zu manipulieren wurde mit einer Studie der Transporteigenschaften kombiniert. Die Anwendung von großflächigen Charakterisierungsmethoden wie XRD, Raman und IR-Spektroskopie, erlaubte die Bestimmung der Phase und des Fehlstellenordnungsgrades von GST und zeigte eindeutig, dass die Fehlstellenordnung für den Metall-Isolator-Übergang (MIT) verantwortlich ist. Insbesondere wird durch das Vergleichen von XRD-Messungen mit elektrischen Messungen gezeigt, dass der Übergang von isolierend zu leitend erfolgt, sobald eine Ordnung der Kristallgitterlücken einsetzt. Dieses Phänomen tritt in der kubischen Kristallphase auf, wenn Gitterfehlstellen in GST von einem ungeordneten in einen geordneten Zustand übergehen. Im zweiten Teil des Kapitels wird eine Kombination aus FIR- und Raman-Spektroskopie zur Untersuchung der Vibrationsmoden und des Ladungsträgerverhaltens in der amorphen und der kristallinen Phase angewendet, um Aktivierungsenergien für die Elektronenleitung, sowohl für die kubische, als auch für die trigonale Kristallphase von GST zu bestimmen. Hier ist es wichtig zu erwähnen, dass, in Übereinstimmung mit Ergebnissen aus anderen Untersuchungen, das Auftauchen eines MIT beim Übergang zwischen der ungeordneten und der geordneten kubischen Phase beobachtet wurde. Schlussendlich wurden verschiedene sogenannte Pump/Probe Technik, bei der man das Material mit dem Laser anregt und die Röntgenstrahlung oder Terahertz (THz)-spektroskopie als Sonde nutzt, angewandt. Dies dient um ultra-schnelle Dynamiken zu erfassen, die zum Verständnis der Umschaltmechanismen nötig sind. Die Empfindlichkeit der THz-Messungen hinsichtlich der Leitfähigkeit, sowohl in GST, als auch in GeTe/Sb2Te3 Übergittern zeigte, dass die nicht-thermische Natur der Übergitterumschaltprozesse mit Grenzflächeneffekten zusammenhängt und . Der Ablauf wird mit beeindruckender geringer Laser-Fluenz erreicht. Dieses Ergebnis stimmt mit Berichten aus der Literatur überein, in denen ein Kristall-zu Kristallwechsel von auf Übergittern basierenden Speicherzellen für effizienter gehalten wird als GST Schmelzen, was zu einen ultra-schwachen Energieverbrauch führt.
The growth by molecular beam epitaxy of Ge-Sb-Te (GST) alloys resulting in quasi-single-crystalline films with ordered configuration of intrinsic vacancies is demonstrated. It is shown how a structural characterization based on transmission electron microscopy, X-ray diffraction and density functional theory, allowed to unequivocally assess the vacancy ordering in GST samples, which was so far only predicted. The understanding of the ordering process enabled the realization of a fine tuning of the ordering degree itself, which is linked to composition and crystalline phase. A phase diagram with the different growth windows for GST is obtained. High degree of vacancy ordering in GST is also obtained through annealing and via femtosecond-pulsed laser crystallization of amorphous material deposited on a crystalline substrate, which acts as a template for the crystallization. This finding is remarkable as it demonstrates that it is possible to create a crystalline GST with ordered vacancies by using different fabrication procedures. Growth and structural characterization of GeTe/Sb2Te3 superlattices is also obtained. Their structure resembles that of ordered GST, with exception of the Sb and Ge layers stacking sequence. The possibility to tune the degree of vacancy ordering in GST has been combined with a study of its transport properties. Employing global characterization methods such as XRD, Raman and Far-Infrared spectroscopy, the phase and ordering degree of the GST was assessed, and unequivocally demonstrated that vacancy ordering in GST drives the metal-insulator transition (MIT). In particular, first it is shown that by comparing electrical measurements to XRD, the transition from insulating to metallic behavior is obtained as soon as vacancies start to order. This phenomenon occurs within the cubic phase, when GST evolves from disordered to ordered. In the second part of the chapter, a combination of Far-Infrared and Raman spectroscopy is employed to investigate vibrational modes and the carrier behavior in amorphous and crystalline phases, enabling to extract activation energies for the electron conduction for both cubic and trigonal GST phases. Most important, a MIT is clearly identified to occur at the onset of the transition between the disordered and the ordered cubic phase, consistently with the electrical study. Finally, pump/probe schemes based on optical-pump/X-ray absorption and Terahertz (THz) spectroscopy-probes have been employed to access ultrafast dynamics necessary for the understanding of switching mechanisms. The sensitivity of THz-probe to conductivity in both GST and GeTe/Sb2Te3 superlattices showed that the non-thermal nature of switching in superlattices is related to interface effects, and can be triggered by employing up to one order less laser fluences if compared to GST. Such result agrees with literature, in which a crystal to crystal switching of superlattice based memory cells is expected to be more efficient than GST melting, therefore enabling ultra-low energy consumption.

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Carria, Egidio. "Amorphous-Crystal Phase Transitions in Ge2Sb2Te5 and GexTe1-x alloys." Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/933.

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Aim of this work was the investigation of the phase transitions in Ge2Sb2Te5 and GexTe1-x thin films. These alloys are of interest since they exhibit an excellent combination of electrical-optical and phase changing characteristics for memory applications. In particular we have focused our attention on the amorphous-crystal transition. We have then discussed the correlation between the local order in the amorphous network and the crystallization kinetics. To this aim we have modified the properties of the amorphous phase by laser and ion irradiation looking to the consequent variation in the phase transition speed.

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Bragaglia, Valeria [Verfasser], Henning [Gutachter] Riechert, Simone [Gutachter] Raoux, and David [Gutachter] Wright. "Epitaxial Growth and Ultrafast Dynamics of GeSbTe Alloys and GeTe/Sb2Te3 Superlattices / Valeria Bragaglia ; Gutachter: Henning Riechert, Simone Raoux, David Wright." Berlin : Humboldt-Universität zu Berlin, 2017. http://d-nb.info/1185579133/34.

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Gourvest, Emmanuel. "Développement et élaboration par MOCVD de matériaux à changement de phase à base d'alliages GeTe : applications aux mémoires embarquées pour la microélectronique." Phd thesis, Grenoble INPG, 2010. https://theses.hal.science/tel-00668137.

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Les mémoires à changement de phase électroniques (PCRAM) sont l'un des candidats les plus prometteurs pour la prochaine génération de mémoires non-volatiles. Cette technologie présente cependant deux inconvénients majeurs : un temps de rétention de l'information court pour des températures de fonctionnement élevées et une consommation électrique trop importante. Le premier objectif de ce travail a été de développer de nouveaux matériaux à changement de phase par PVD pour remplacer le traditionnel Ge2Sb2Te5, inadapté pour des applications embarquées. Le second objectif a été d'élaborer le matériau sélectionné par MOCVD assisté plasma afin d'évaluer la faisabilité de dispositifs confinés nécessitant des courants de fonctionnement faibles. L'étude du matériau binaire GeTe a montré des performances supérieures à celles de Ge2Sb2Te5 avec notamment une estimation du temps de rétention de l'information de dix ans à 110°C. L'impact de l'incorporation d'éléments dopants N ou C dans GeTe a été évalué en prévision du développement MOCVD. Il a été démontré une nette augmentation de la stabilité thermique des matériaux dopés, que nous expliquons par la formation d'une phase amorphe de type nitrure ou carbure lors de la cristallisation. L'utilisation d'un système de dépôt MOCVD par injection pulsée avec assistance plasma a permis de réaliser des couches minces conformes de GeTe à l'état cristallin ou amorphe, présentant des propriétés de transition de phase similaires à celles de GeTe de référence élaboré par PVD
Phase-Change Random Access Memories (PCRAM) are one of the most promising candidates for next generation of nonvolatile memories. However, this technology presents two major drawbacks: an archival life for high operating temperatures too short and power consumption too high. The first objective of this work was to develop new phase change materials by PVD to replace the common Ge2Sb2Te5 unsuitable for embedded applications. The second objective was to develop the targeted material by plasma-assisted MOCVD to assess the feasibility of confined devices requiring low operating currents. The study of binary GeTe material showed higher performance than Ge2Sb2Te5 including an estimated archival life up to ten years at 110°C. The impact of the incorporation of doping elements N and C in GeTe has been under evaluation for development of MOCVD. It has been shown a pronounced increase in thermal stability of doped materials that we explain by the formation of an amorphous phase of nitride or carbide during crystallization. Using a pulsed liquid MOCVD tool with plasma assistance allowed depositing GeTe thin films in crystalline or amorphous phase, with properties of phase transition similar to sputtered GeTe ones

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Scholtka, Bettina, Mandy Schneider, Ralph Melcher, Tiemo Katzenberger, Daniela Friedrich, Kornelia Berghof-Jäger, Wolfgang Scheppach, and Pablo Steinberg. "A gene marker panel covering the Wnt and the Ras-Raf-MEK-MAPK signalling pathways allows to detect gene mutations in 80% of early (UICC I) colon cancer stages in humans." Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2010/4458/.

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Background: Very recently a gene marker panel that allows the mutational analysis of APC, CTNNB1, B-RAF and K-RAS was conceived. The aim of the present study was to use the 4-gene marker panel covering the Wnt and Ras-Raf-MEK-MAPK signalling pathways to determine the percentage of sporadic colorectal carcinomas (CRC) carrying at least one of the four above-mentioned genes in a mutated form alone and/or in combination with microsatellite instability (MSI) and to compare the sensitivity of the gene marker panel used in this study with that of gene marker panels previously reported in the scientific literature. Methods: CTNNB1 and B-RAF were screened by PCR-single-strand conformation polymorphism analysis and K-RAS gene mutations by restriction fragment length polymorphism analysis. For the mutational analysis of the APC gene mutation cluster region (codons 1243–1567) direct DNA sequencing was performed. The U.S. National Cancer Institute microsatellite panel (BAT25, BAT26, D2S123, D5S346 and D17S250) was used for MSI analysis. Results: It could be shown that about 80% of early stage CRC (UICC stages I and II) and over 90% of CRC in the UICC stage IV carried at least one mutated gene and/or showed MSI. No significant increase in the gene mutation frequencies could be determined when comparing tumours in the UICC stage I with those in UICC stage IV. Conclusions: When compared with previously published gene marker panels the 4-gene marker panel used in the present study shows an excellent performance, allowing to detect genetic alterations in 80–90% of human sporadic CRC samples analyzed.

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Singh, Sanjleena. "Characterisation of mesenchymal cells from osteophytes in osteoarthritis." Thesis, Queensland University of Technology, 2009. https://eprints.qut.edu.au/31298/1/Sanjleena_Singh_Thesis.pdf.

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Osteophytes form through the process of chondroid metamorphosis of fibrous tissue followed by endochondral ossification. Osteophytes have been found to consist of three different mesenchymal tissue regions including endochondral bone formation within cartilage residues, intra-membranous bone formation within fibrous tissue and bone formation within bone marrow spaces. All these features provide evidence of mesenchymal stem cells (MSC) involvement in osteophyte formation; nevertheless, it remains to be characterised. MSC from numerous mesenchymal tissues have been isolated but bone marrow remains the “ideal” due to the ease of ex vivo expansion and multilineage potential. However, the bone marrow stroma has a relatively low number of MSC, something that necessitates the need for long-term culture and extensive population doublings in order to obtain a sufficient number of cells for therapeutic applications. MSC in vitro have limited proliferative capacity and extensive passaging compromises differentiation potential. To overcome this barrier, tissue derived MSC are of strong interest for extensive study and characterisation, with a focus on their potential application in therapeutic tissue regeneration. To date, no MSC type cell has been isolated from osteophyte tissue, despite this tissue exhibiting all the hallmark features of a regenerative tissue. Therefore, this study aimed to isolate and characterise cells from osteophyte tissues in relation to their phenotype, differentiation potential, immuno-modulatory properties, proliferation, cellular ageing, longevity and chondrogenesis in in vitro defect model in comparison to patient matched bone marrow stromal cells (bMSC). Osteophyte derived cells were isolated from osteophyte tissue samples collected during knee replacement surgery. These cells were characterised by the expression of cell surface antigens, differentiation potential into mesenchymal lineages, growth kinetics and modulation of allo-immune responses. Multipotential stem cells were identified from all osteophyte samples namely osteophyte derived mesenchymal stem cells (oMSC). Extensively expanded cell cultures (passage 4 and 9 respectively) were used to confirm cytogenetic stability and study signs of cellular aging, telomere length and telomerase activity. Cultured cells at passage 4 were used to determine 84 pathway focused stem cell related gene expression profile. Micro mass pellets were cultured in chondrogenic differentiation media for 21 days for phenotypic and chondrogenic related gene expression. Secondly, cell pellets differentiated overnight were placed into articular cartilage defects and cultured for further 21 days in control medium and chondrogenic medium to study chondrogenesis and cell behaviour. The surface antigen expression of oMSC was consistent with that of mesenchymal stem cells, such as lacking the haematopoietic and common leukocyte markers (CD34, CD45) while expressing those related to adhesion (CD29, CD166, CD44) and stem cells (CD90, CD105, CD73). The proliferation capacity of oMSC in culture was superior to that of bMSC, and they readily differentiated into tissues of the mesenchymal lineages. oMSC also demonstrated the ability to suppress allogeneic T-cell proliferation, which was associated with the expression of tryptophan degrading enzyme indoleamine 2,3 dioxygenase (IDO). Cellular aging was more prominent in late passage bMSC than in oMSC. oMSC had longer telomere length in late passages compared with bMSC, although there was no significant difference in telomere lengths in the early passages in either cell type. Telomerase activity was detectable only in early passage oMSC and not in bMSC. In osteophyte tissues telomerase positive cells were found to be located peri vascularly and were Stro-1 positive. Eighty-four pathway-focused genes were investigated and only five genes (APC, CCND2, GJB2, NCAM and BMP2) were differentially expressed between bMSC and oMSC. Chondrogenically induced micro mass pellets of oMSC showed higher staining intensity for proteoglycans, aggrecan and collagen II. Differential expression of chondrogenic related genes showed up regulation of Aggrecan and Sox 9 in oMSC and collagen II in bMSC. The in vitro defect models of oMSC in control medium showed rounded and aggregated cells staining positively for proteoglycan and presence of some extracellular matrix. In contrast, defects with bMSC showed fragmentation and loss of cells, fibroblast-like cell morphology staining positively for proteoglycans. For defects maintained in chondrogenic medium, rounded, aggregated and proteoglycan positive cells were found in both oMSC and bMSC cultures. Extracellular matrix and cellular integration into newly formed matrix was evident only in oMSC defects. For analysis of chondrocyte hypertrophy, strong expression of type X collagen could be noticed in the pellet cultures and transplanted bMSC. In summary, this study demonstrated that osteophyte derived cells had similar properties to mesenchymal stem cells in the expression of antigen phenotype, differential potential and suppression of allo-immune response. Furthermore, when compared to bMSC, oMSC maintained a higher proliferative capacity due to a retained level of telomerase activity in vitro, which may account for the relatively longer telomeres delaying growth arrest by replicative senescence compared with bMSC. oMSC behaviour in defects supported chondrogenesis which implies that cells derived from regenerative tissue can be an alternative source of stem cells and have a potential clinical application for therapeutic stem cell based tissue regeneration.

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MANCA, CLAUDIA. "Analisi integrata dell'espressione di geni/microrna in un modello di epatocancerogenesi sperimentale." Doctoral thesis, Università degli Studi di Cagliari, 2013. http://hdl.handle.net/11584/266231.

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Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world, accounting for an estimated half million deaths annually, and represents one of the major health problems. Although much is known about the cellular changes that lead to HCC, the molecular pathogenesis of HCC is not yet well understood. Gene expression studies conducted with microarray techniques and real-time PCR, suggest that tumors are characterized by an aberrant activation of signal transduction pathways involved in proliferation, survival, cell differentiation and angiogenesis. However, for HCC, these studies don’t allow the identification of a "signature" or a single specific pathway that is predominantly involved in the development and prognosis of the malignancy. Recently it has become clear that the classification and stratification of cancer can be performed not only through the analysis of gene expression, but also by analyzing the expression of microRNAs, small non-coding RNA molecules that negatively control gene expression and protein synthesis. In the present study we performed an integrated analysis of genome-wide mRNA and microRNA (miR) expression profiles to characterize the molecular events involved in the step-by-step progression (preneoplastic nodules-adenoma-early HCC-advanced HCC) of hepatocellular carcinoma (HCC) in the rat Resistant-Hepatocyte (R-H) model. Interestingly, while analysis of the transcriptome clustered together preneoplastic lesions and advanced HCC, suggesting that the majority of the genes dysregulated in HCC are already aberrantly expressed in early lesions, miRNome analysis did not co-cluster the two populations but, very interestingly, stratified the lesions according to their stage of progression to HCC. The results also unveiled specific genes/miRs, altered in the very early steps of the carcinogenic process, in the transition from adenoma to early HCC or in the progression to advanced HCC. By assessing the correlation between the expression of each miRNA and its targets, we determined that distinct pathways are aberrantly activated in different stages of the carcinogenic process. This integrated approach was also able to identify molecular events discriminating the preneoplastic lesions that will progress to HCC from those that spontaneously regress. Finally, 110 orthologous genes were almost super imposable between rat and human HCC signatures, supporting the value of the R-H model in recapitulating human liver cancer. Conclusions: This systematic analysis deciphered the molecular phenotypes of the several steps involved in the onset and progression of HCC and investigated their variations at mRNA and miR levels. In view of the striking similarity between mRNA and miRs commonly dysregulated in rat and human HCC, our results provide a valuable source for future studies and highlight promising genes, miRNAs, pathways and processes which may be useful for diagnostic or therapeutic applications.

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Vinod, E. M. "Investigations of Phase Change Memory Properties of Selenium Doped GeTe and Ge2Sb2Te5." Thesis, 2013. http://etd.iisc.ac.in/handle/2005/3339.

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GeTe and Ge2Sb2Te5 alloys are potential candidates for non-volatile phase change random access memories (PCRAM). For electrical data storage applications the materials should have stable amorphous and crystalline phases, fast crystallization time, low power to switch, and high crystallization activation energy (to be stable at normal operating temperatures). Phase change memories can be tuned through compositional variations to achieve sufficient phase change contrast and thermal stability for data retention. Selenium is one of the attractive choices to use as an additive material owing to its flexible amorphous structure and a variety of possible applications in optoelectronics and solar cells. GeSb2Te3Se alloy, in which 25 at.% of Se substituted for Te, show a higher room temperature resistance with respect to parent GeSb2Te4 alloy, but the transition temperature is lowered which will affect the thermal stability. The RESET current observed for Sb65Se35 alloys were reduced and the crystallization speed increased 25 % faster with respect to Ge2Sb2Te5. Alloys of Ga-Sb-Se possess advantages such as higher crystallization temperatures, better data retention, higher switching speed, lower thermal conductivity and lower melting point than the GST, but the resistance ratio is limited to about two orders of magnitude. This affects the resistance contrast and data readability. It is with this background a study has been carried out in GeTe and GeSbTe system with Se doping. Studies on structural, thermal and optical properties of these materials all through the phase transition temperatures would be helpful to explore the feasibility of phase change memory uses. Thin films along with their bulk counterparts such as (GeTe)1-x Sex ( 0 < x ≤ 0.50) and (GST)1-xSex (0 < x ≤ 0.50), including GeTe and GST alloys, have been prepared. The results are presented in four chapters apart from the Introduction and Experimental techniques chapters. The final chapter summarizes the results. Chapter 1 provides an introduction to chalcogenide glasses, phase change memory materials and their applications. The fundamental properties of amorphous solids, basic phase change properties of Ge2Sb2Te5 and GeTe alloys and their applications are presented in detail. Various doping studies on GeTe and Ge2Sb2Te5 reported in literatures are reviewed. The limitations, challenges, future and scope of the present work are presented. In chapter 2, the experimental techniques used for thin film preparation, electrical characterizations, optical characterization and surface characterizations etc. are explained. Chapter 3 deals entirely on Ge2Sb2Te5 films studied throughout the phase transition, by annealing at different temperatures. Changes in sheet resistance, optical transmission, morphology and surface bonding characteristics are analyzed. The crystallization leads to an increase of roughness and the resistance changes to three orders of magnitude at 125 oC. Optical studies show distinct changes in transmittance during phase transitions and the optical parameters are calculated. Band gap contrast and disorder variation with annealing temperatures are explained. The surface bonding characteristics studied by XPS show Ge-Te, Sb-Te bonds are present in both amorphous and crystalline phases. The temperature dependent modifications of the band structure of amorphous GST films at low temperatures have been little explored. The band gap increment of around 0.2 eV is observed at low temperature (4.2 K) compared to room temperature 300 K. Other optical parameters like Urbach energy and B1/2 are studied at different temperatures and are evaluated. The observed changes in optical band gap (Eopt) are fitted to Fan’s one phonon approximation, from which a phonon energy (ћω) corresponding to a frequency of 3.59 THz resulted. The frequency of 3.66 THz optical phonons has already been reported by coherent phonon spectroscopy experiment in amorphous GST. This opens up an indirect method of calculating the phonon frequency of the amorphous phase change materials. Chapter 4 constitutes comparison of optical, electrical and structural investigation of GST and (GST)1-xSex films. It is well known that GST alloys have vacancy in their structure, which leads to the possibility of switching between the amorphous and crystalline states with minimum damage. Added Se may occupy the vacancy or change the bonding characteristics which intern may manifest in the possibility of change in optical and electrical parameters. The structural studies show a direct amorphous to hexagonal transition in (GST)1-xSex, where x ≥ 0.10 at.%. Raman spectra of the as deposited and annealed (GST)1-xSex films show structural modifications. The infrared transmission spectra indicate a shift in absorption edges from low to high photon energy when Se concentration increases in GST. Band gap values calculated from Tauc plot show the band gap increment with Se doping. It is noted that a small amount of Se doping increases the resistance of the amorphous and crystalline phases and maintains the same orders of resistance contrast. This will be beneficial as it improves the thermal stability and reduces the write current in a device. Switching studies show an increasing threshold voltage as the Se doping concentration increases. Chapter 5 comprises compositional dependent investigations of the bulk GeTe chalcogenides alloys added with different selenium concentrations. The XRD investigations on bulk (GeTe)1-xSex (x = 0.0, 0.02, 0.10, 0.20 and 0.50 at.%) alloys show that the crystalline structure of GeTe alloys does not affect ≤ 0.20 at.% of Se concentration. With increasing amount of Se concentration the alloys gets modified in to a homogeneous amorphous structure. This result has been verified from the XRD, Raman, XPS, SEM and DSC measurements. The possibility that Se occupying the Ge vacancy sites in GeTe structure is explained. Since Se is an easy glass former, the amorphousness increases in the alloys due to new amorphous phases formed by the Se with other elements. It is shown from Raman and XPS analysis that the Ge-Te bonds exists up to Se 0.20 at.% alloys. Ge-Se and GeTe2 bonds are increasing with increasing Se at.%. Melting temperature has found decreases and the reduction in melting point may reduces the RESET current. Further studies on switching behavior may bring out its usefulness. Chapter 6 deals with studies on (GeTe)1-xSex films for phase change memory applications based on the insight received from their bulk study. Even at low at.% addition of Se makes the as prepared (GeTe)1-xSex film amorphous. At 200 oC, GeTe crystalline structure is evolved and the intensity of the peaks reduces in the alloys with increase of Se content. At 300 oC, more evolved GeTe crystalline structure is seen compared to 200 oC annealed films whereas 0.20 at.% Se alloy remain amorphous. Resistance and thermal studies shows increase in crystallization temperature. It is expected that Se sits in the vacancies of the GeTe crystalline structural formation. This may also account for the increased threshold voltages with increasing Se doping. The band gap increase with increase of Se at.% signifying the possibility of band gap tuning in the material. Possible explanation for the increased order in GeTe due to Se doping is presented. The modifications in the alloy with Se addition can be explained with the help of chemical bond energy approach. Those bonds having higher energy leads to increased average bond energy of the system and hence the band gap. The XPS core level spectra and Raman spectra investigation clearly shows the GeTe bonds are replaced by Ge-Se bonds and GeTe2 bonds. The 0.10 at.% Se alloy is found to have a higher thermal stability in the amorphous state and maintains a gigantic resistance contrast compared to other Se concentration alloys. This alloy can be considered as an ideal candidate for multilevel PCM applications. Chapter 7 summarizes the major findings from this work and the scope for future work.

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Vinod, E. M. "Investigations of Phase Change Memory Properties of Selenium Doped GeTe and Ge2Sb2Te5." Thesis, 2013. http://etd.iisc.ernet.in/2005/3339.

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Shekhawat, Roopali. "Effect of As and Se substitution on the Phase Change properties of GeTe based alloys." Thesis, 2022. https://etd.iisc.ac.in/handle/2005/5996.

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Phase-change memory (PCM) is a key enabling technology for non-volatile electrical data storage at the nanometer scale. A PCM device consists of a small active volume of phase-change material between two electrodes. In PCM, data are stored using the electrical resistance contrast between a high-conductive crystalline phase and a low-conductive amorphous phase. An appealing attribute of PCM is that the stored data is retained for a very long time (typically 10 years at room temperature). This property could enable PCM to be used for non-volatile storage such as Flash and hard disk drives, while operating almost as fast as high-performance volatile memory such as dynamic random-access memory (DRAM). Primarily, chalcogenide alloys are used as an active element in PCM devices. The device performance relies on the structural variations, thus understanding the structural modulations with variation in composition is of great importance. Current work is focused on GeTe based alloys Ge2Sb2−xAsxTe5 ( 0 ≤ x ≤ 2.0) and GeTe1−xSex ( 0 ≤ x ≤ 1.0). The objective is to study the effect of the substitution of smaller atoms in place of larger atoms on the structural and phase change properties. The substitution of As and Se is expected to influence the ionicity and hybridization capability of GeTe based alloys to a larger extent as predicted by Littlewoods ionicity - hybridization map for group IV-VI alloys. The As substituted for Sb in Ge2Sb2Te5 (GST) samples i.e. Ge2Sb2−xAsxTe5 , crystallize at higher temperatures compared to the parent GST. During the phase change, a direct transition from amorphous to the stable hexagonal structure for x > 1.0 has been observed. A distinct two-step transition in Sb rich samples and a single step transition for As rich samples are observed in R-T measurements with a high contrast in electrical resistivity. A composition-dependent Metal-Insulator Transition (MIT) is also observed in these samples. In GeTe1−xSex alloys, it is observed that with increasing Se substitution, the structure transforms from rhombohedral to orthorhombic, supported by Rietveld refinement analysis. In GeTe1−xSex thin films the transition temperature for amorphous to crystalline phase shows an increasing trend with the Se substitution. The contrast in electrical resistivity between the amorphous and crystalline states is 104 for GeTe, and with the Se substitution, the contrast increases considerably to 106 for GeTe0.5Se0.5. Devices fabricated with thin films show that the threshold current decreases with the Se substitution indicating a reduction in the power required for WRITE operation. The present study shows that the crystalline structure, resistivity, optical bandgap, transition temperature, data retention and threshold voltage can be effectively controlled and tuned by the substitution of Se for Te in GeTe and As for Sb in Ge2Sb2Te5, which is conducive for phase change memory applications.
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Книги з теми "GeTe alloys"

Reznik, Semen, Zurab Mebaduri, and Elena Duhanina. Economy. ru: INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1020633.

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The textbook provides the basics of economic knowledge, as well as discusses technologies that allow junior students to actively participate in the educational process and practical activities, to get a prestigious job while still studying at the university. Special attention is paid to the effective use of their abilities and time, career management. For junior students of higher educational institutions studying in the areas of "Management", "Personnel Management" and "Economics".

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Bashkatov, Alexander. Modeling in OpenSCAD: examples. ru: INFRA-M Academic Publishing LLC., 2019. http://dx.doi.org/10.12737/959073.

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The tutorial is an introductory course to the study of the basics of geometric modeling for 3D printing using the programming language OpenSCAD and is built on the basis of descriptions of instructions for creating primitives, determining their properties, carrying out transformations and other service operations. It contains a large number of examples with detailed comments and description of the performed actions, which allows you to get basic skills in creating three-dimensional and flat models, exporting and importing graphical data. Meets the requirements of the Federal state educational standards of higher education of the last generation. It can be useful for computer science teachers, students, students and anyone who is interested in three-dimensional modeling and preparation of products for 3D printing.

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Samovich, Yuliya, and Ramil Sharifullin. International protection of human rights: universal mechanisms. ru: Publishing Center RIOR, 2021. http://dx.doi.org/10.29039/02042-5.

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The tutorial examines the universal mechanism for the international protection of individual rights, in particular the United Nations system and treaty bodies. Special attention is paid to the analysis of the effectiveness of the international control mechanism and proposals for its improvement. The content will allow students to both independently fill in the missed material and get acquainted with additional. The manual is recommended for students in the direction 40.04.01 "Jurisprudence" (magistracy), graduate students, specialty students.

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Kas'yanova, Svetlana, Zh Kevorkova, M. Safonova, N. V. Laktionova, and N. V. Kulish. Audit. ru: INFRA-M Academic Publishing LLC., 2022. http://dx.doi.org/10.12737/1863115.

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The textbook contains a set of developments in the field of audit. All the material is distributed on topics between theoretical, practical and seminar classes, as well as independent work of students in the form of discussions, presentations, test tasks, situational tasks. The theoretical and applied aspects of the organization and conduct of the audit are described, which allow assessing the effectiveness of the management of its affairs with due completeness and reliability. The latest legislative changes have been taken into account. The use of methodological materials will allow each student to rationally allocate their time while studying the discipline, get a sufficiently adequate aggregate score and rating assessment and form professional skills. Meets the requirements of the federal state educational standards of higher education of the latest generation. For undergraduate students studying in the field of training 38.03.01 "Economics".

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Kas'yanova, Svetlana. Accounting in the restaurant and hotel business and tourism. ru: INFRA-M Academic Publishing LLC., 2022. http://dx.doi.org/10.12737/1171922.

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The textbook outlines the theoretical and applied aspects of the organization and accounting features, which allow assessing the effectiveness of its management with a proper degree of completeness and reliability. The latest legislative changes have been taken into account. All the material is distributed on topics between theoretical, practical and seminar classes, as well as independent work of students in the form of discussions, presentations, situational tasks, test tasks. The use of methodological materials will allow students to rationally allocate their time while studying the discipline, get a sufficiently adequate aggregate score and rating assessment and form professional skills. Meets the requirements of the federal state educational standards of higher education of the latest generation. The textbook contains a set of developments for the preparation of bachelors in the field of accounting that meet the requirements of the educational program in the field of training 38.03.01 "Economics".

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Reznik, Semen, Aleksey Chernicov, Ol'ga Sazykina, Irina Igoshina, Vladimir Bondarenko, and Vladimir Dorofeev. Career management. ru: INFRA-M Academic Publishing LLC., 2023. http://dx.doi.org/10.12737/1898406.

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The technologies of managing their own professional career are considered, which allow junior students to actively engage in the educational process and practical activities, to get a prestigious job even during their studies at the university. Special attention is paid to the effective use of their abilities and time, managing their own career and work behavior in the organization. Meets the requirements of the federal state educational standards of higher education of the latest generation. For undergraduate students of higher educational institutions studying in the areas of training "Management", "Personnel Management", "State and municipal Management", as well as other areas of training.

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Pustovaya, Larisa, and Besik Meshi. Methods and devices of environmental control. Environmental monitoring. ru: INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1058966.

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The textbook is designed to meet the need for a highly specialized set of professional knowledge necessary for the training of highly qualified personnel of environmental specialties. The presented material allows us to get an idea of the organization and effective implementation of environmental monitoring, the organization of industrial environmental control and management, the analysis of characteristics and changes of objects of economic activity using the necessary methods and means of such research. The basic principles of sampling and sample preparation, modern methods and means of environmental monitoring, the basics of metrological and laboratory-analytical support for environmental control are described. The training material is accompanied by up-to-date references to the current legislative framework of the Russian Federation. Meets the requirements of the federal state educational standards of higher education of the latest generation and the current bachelor's degree program in the areas of training "Technosphere Safety", "Biotechnical systems and Technologies". It can be useful and interesting for students, undergraduates, postgraduates, as well as teachers specializing in environmental safety.

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Reznik, Semen, and Irina Igoshina. Management. ru: INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1514558.

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The system of intensive introduction of junior students in the direction of "Management"is presented. The theoretical foundations of management and requirements for the main educational program for an enlarged group of training areas 38.00.00 "Economics and Management"are given. The technologies of life activity that allow students to actively engage in the educational process and practical activities, get a job on the profile of training even during their studies at the university are considered. Special attention is paid to the formation of personal competitiveness and entrepreneurship of the student. Meets the requirements of the federal state educational standards of higher education of the latest generation. For junior students of higher educational institutions.

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Hannouch, Hanin. Gabriel Lippmann's Colour Photography. Nieuwe Prinsengracht 89 1018 VR Amsterdam Nederland: Amsterdam University Press, 2022. http://dx.doi.org/10.5117/9789463728553.

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Physicist Gabriel Lippmann’s (1845–1921) photographic process is one of the oldest methods for producing colour photographs. So why do the achievements of this 1908 Nobel laureate remain mostly unknown outside niche circles? Using the centenary of Lippmann’s death as an opportunity to reflect upon his scientific, photographic, and cultural legacy, this book is the first to explore his interferential colour photography. Initially disclosed in 1891, the emergence of this medium is considered here through three shaping forces: science, media, and museums. A group of international scholars reassess Lippmann’s reception in the history of science, where he is most recognised, by going well beyond his endeavours in France and delving into the complexity of his colour photography as a challenge to various historiographies. Moreover, they analyse colour photographs as optical media, thus pluralising Lippmann photography’s ties to art, cultural and imperial history, as well as media archaeology. The contributors also focus on the interferential plate as a material object in need of both preservation and exhibition, one that continues to fascinate contemporary analogue photographers. This volume allows readers to get to know Lippmann, grasp the interdisciplinary complexity of his colourful work, and ultimately expand his place in the history of photography.

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Postoutenko, Kirill, ed. Totalitarian Communication. Bielefeld, Germany: transcript Verlag, 2010. http://dx.doi.org/10.14361/9783839413937.

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Totalitarianism has been an object of extensive communicative research since its heyday: already in the late 1930s, such major cultural figures as George Orwell or Hannah Arendt were busy describing the visual and verbal languages of Stalinism and Nazism. After the war, many fashionable trends in social sciences and humanities (ranging from Begriffsgeschichte and Ego-Documentology to Critical Linguistics and Critical Discourse Analysis) were called upon to continue this media-centered trend in the face of increasing political determination of the burgeoing field. Nevertheless, the integration of historical, sociological and linguistic knowledge about totalitarian society on a firm factual ground remains the thing of the future. This book is the first step in this direction. By using history and theory of communication as an integrative methodological device, it reaches out to those properties of totalitarian society which appear to be beyond the grasp of specific disciplines. Furthermore, this functional approach allows to extend the analysis of communicative practices commonly associated with fascist Italy, Nazi Germany and Soviet Union, to other locations (France, United States of America and Great Britain in the 1930s) or historical contexts (post-Soviet developments in Russia or Kyrgyzstan). This, in turn, leads to the revaluation of the very term »totalitarian«: no longer an ideological label or a stock attribute of historical narration, it gets a life of its own, defining a specific constellation of hierarchies, codes and networks within a given society.

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Renneberg, Reinhard, Viola Berkling, and Iris Rapoport. "Gene mit Geschmack." In Alles Bio oder was?, 61–63. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-50278-5_18.

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Hill, Eric M., Cheng-Yi Chen, Florencia del Viso, Lacey R. Ellington, Shuonan He, Ahmet Karabulut, Ariel Paulson, and Matthew C. Gibson. "Manipulation of Gene Activity in the Regenerative Model Sea Anemone, Nematostella vectensis." In Methods in Molecular Biology, 437–65. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2172-1_23.

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AbstractWith a surprisingly complex genome and an ever-expanding genetic toolkit, the sea anemone Nematostella vectensis has become a powerful model system for the study of both development and whole-body regeneration. Here we provide the most current protocols for short-hairpin RNA (shRNA)-mediated gene knockdown and CRISPR/Cas9-targeted mutagenesis in this system. We further show that a simple Klenow reaction followed by in vitro transcription allows for the production of gene-specific shRNAs and single guide RNAs (sgRNAs) in a fast, affordable, and readily scalable manner. Together, shRNAknockdown and CRISPR/Cas9-targeted mutagenesis allow for rapid screens of gene function as well as the production of stable mutant lines that enable functional genetic analysis throughout the Nematostella life cycle.

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Renwick, Robin. "‘We will get nothing from the Americans but words’." In Fighting with Allies, 21–26. London: Palgrave Macmillan UK, 1996. http://dx.doi.org/10.1057/9780230379824_3.

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Steenblik, Ralph Spencer. "Developing a Hybrid Intelligence Through Hacking the Machine Learning Neural Style Transfer Process for Possible Futures." In Computational Design and Robotic Fabrication, 284–92. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-8637-6_25.

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AbstractThis article highlights work using machine learning in collaboration with designers for speculative world building. The process is unique because of the feedback loop, between the designer and the computational process. Worldbuilding is a speculative practice and requires vision and courage on the part of the designer. Working with machine learning neural style transfer (NST) allows the designers to consider possibilities humanity may not otherwise allow ourselves to imagine. This is important because human imagination paves the path for the future of humankind. Imagining a sustainable future requires considering unconventional solutions. Imagining non-probable futures allows humanity to glean desirable aspects to strive for. Even if a conceived future is impossible within the built environment, there are many opportunities for people to inhabit these environments virtually. Letting yourself get lost in these places is a form of travel, even when conditions limit one's ability to physically do so.

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d’Herbemont, Olivier, and Bruno César. "Remain the White Knight: Get Allies to Attack." In Managing Sensitive Projects, 209–10. London: Palgrave Macmillan UK, 1998. http://dx.doi.org/10.1007/978-1-349-14842-4_22.

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Feng, Yifan, Yutong Ai, and Hao Jiang. "LLE Based K-Nearest Neighbor Smoothing for scRNA-Seq Data Imputation." In Financial Mathematics and Fintech, 203–15. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-2366-3_11.

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AbstractThe single-cell RNA sequencing (scRNA-seq) technique allows single cell level of gene expression measurements, but the scRNA-seq data often contain missing values, with a large proportion caused by technical defects failing to detect gene expressions, which is called dropout event. The dropout issue poses a great challenge for scRNA-seq data analysis. In this chapter, we introduce a method based on KNN-smoothing: LLE-KNN-smoothing to impute the dropout values in scRNA-seq data and show that the LLE-KNN-smoothing greatly improves the recovery of gene expression in cells and shows better performance than state-of-the-art imputation methods on a number of scRNA-seq data sets.

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Ouedraogo, Wend Yam Donald Davy, and Aida Ouangraoua. "Inferring Clusters of Orthologous and Paralogous Transcripts." In Comparative Genomics, 19–34. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-36911-7_2.

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AbstractThe alternative processing of eukaryote genes allows producing multiple distinct transcripts from a single gene, thereby contributing to the transcriptome diversity. Recent studies suggest that more than 90% of human genes are concerned, and the transcripts resulting from alternative processing are highly conserved between orthologous genes.In this paper, we first present a model to define orthology and paralogy relationships at the transcriptome level, then we present an algorithm to infer clusters of orthologous and paralogous transcripts. Gene-level homology relationships are used to define different types of homology relationships between transcripts and a Reciprocal Best Hits approach is used to infer clusters of isoorthologous and recent paralogous transcripts.We applied the method to transcripts of gene families from the Ensembl-Compara database. The results are agreeing with those from previous studies comparing orthologous gene transcripts. The results also provide evidence that searching for conserved transcripts beyond orthologous genes will likely yield valuable information. The results obtained on the Ensembl-Compara gene families are available at https://github.com/UdeS-CoBIUS/TranscriptOrthology. Supplementary material can be found at https://doi.org/10.5281/zenodo.7750949.

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Lenssen-Erz, Tilman, and Andreas Pastoors. "Reading Spoor." In Reading Prehistoric Human Tracks, 101–18. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-60406-6_6.

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AbstractThe spoor of animals and humans alike contain rich information about an individual and about a momentary activity this individual performed. If the – arguably hard-wired – human ability to read spoor and tracks is sufficiently trained, a footprint allows to glean from it various physical, kinetic, medical, social and psychologic data about an individual, as has been observed among various populations across the globe. The Ju|’hoansi San from northern Namibia still today practice traditional hunting so that tracking is a skill that is required and trained on a daily base. For a good tracker, the information she or he gets from spoor is equally rich on animal and human footprints, and it is not necessary that the tracker has been exposed before to the individual whose spoor she/he reads. In order to allow an assessment of how tenable are the interpretations by contemporary hunter-gatherers of prehistoric human footprints, this chapter elucidates methodological aspects of tracking and situates this ability in an epistemological framework.

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Nathwani, Amit C., Karen M. Gale, Kieran D. Pemberton, David C. Crossman, Edward G. D. Tuddenham, and John H. McVey. "Efficient Gene Transfer into Human Umbilical Vein Endothelial Cells Allows Functional Analysis of the Human Tissue Factor Gene Promoter." In Vascular Endothelium, 302. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4613-0355-8_57.

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Nigro, Domenica, Mark A. Smedley, Francesco Camerlengo, and Sadiye Hayta. "Using Gene Editing Strategies for Wheat Improvement." In A Roadmap for Plant Genome Editing, 183–201. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-46150-7_12.

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AbstractDespite wheat’s global importance, it has trailed behind the other major cereals regarding genomic tools and resources as well as gene transformation. As each gene usually exists as two copies in the tetraploid durum wheat or as three in hexaploid bread wheat, it is very difficult assess gene function and improve important agronomic traits in polyploid wheat with traditional breeding methods. Recent advances allow researchers to use gene editing technologies in wheat which facilitates the opportunity to knockout or modify one, two or all three gene homoeologs simultaneously, which is important to clarify the function and contribution of gene copies in a specific phenotype or trait. CRISPR-Cas technology is now being used routinely for gene knockout. Technological advancement has been rapid within the field, and recently more advance and precise methods have been deployed such as cytidine base editing, adenosine base editing, and prime editing in wheat. Here we summarised gene editing strategies that are presently being applied for wheat improvement.

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Тези доповідей конференцій з теми "GeTe alloys"

Huang, T., X. Cheng, X. Guan, and X. Miao. "Improvement of the half-metallic stability of Co2FeAl heusler alloys by GeTe-doping." In 2015 IEEE International Magnetics Conference (INTERMAG). IEEE, 2015. http://dx.doi.org/10.1109/intmag.2015.7156905.

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Bragaglia, V., A. Schnegg, R. Calarco, and K. Holldack. "Epitaxial GeTe-Sb2Te3 Alloys Probed by Single Cycle THz Pulses of Coherent Synchrotron Radiation." In Fourier Transform Spectroscopy. Washington, D.C.: OSA, 2016. http://dx.doi.org/10.1364/fts.2016.fw3d.3.

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Krancher, Christian, Benjamin Schelnberger, Fabian Hoffmann, Romina Krieg, Ralf Theiß, and Peter Dültgen. "Investigation of Transformation Temperatures, Microstructure, and Deformation Behavior of a Pseudoelastic Cu-Based Shape Memory Alloy." In ASME 2022 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/smasis2022-90933.

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Abstract Cu-based shape memory alloys are a promising alternative to the widely used nitinol. The challenge for their use is related to the application temperature, shape memory properties as well as fabrication, and further processing. Knowledge of the transformation temperatures, microstructure, and deformation behavior is of fundamental importance. Research suggested that Cu-Al-Mn shape memory alloys could fulfill this combination of properties excellent. For this purpose, a Cu-Al-Mn-Ni shape memory alloy was melted, cast, and the produced cast rods were subsequently heat treated. For a first idea of whether the chosen composition is a promising alloy depending on the homogenization time, the transformation temperatures and the resulting microstructure were investigated. The transformation behavior was determined by dynamic differential calorimetry. Microstructure investigations were performed by optical microscopy. In addition, to get a first knowledge concerning the deformation behavior the material was characterized by quasi-static compression tests. To this end, cylindrical specimens were turned from the cast bars. The investigation demonstrates a pseudoelastic behavior of the chosen Cu-Al-Mn-Ni shape memory alloy. The study proves the influence of the homogenization time on the microstructure. Furthermore, excellent deformation behavior and good shape memory properties under compressive loading are shown.

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Seal, Sudip, Michael Moody, Anna Ceguerra, Simon Ringer, Krishna Rajan, and Srinivas Aluru. "Tracking Nanostructural Evolution in Alloys: Large-Scale Analysis of Atom Probe Tomography Data on Blue Gene/L." In 2008 37th International Conference on Parallel Processing (ICPP). IEEE, 2008. http://dx.doi.org/10.1109/icpp.2008.73.

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Hasselqvist, Magnus. "TMF Crack Initiation Lifing of Austenitic Carbide Precipitating Alloys." In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-54333.

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Recent work within DDIT has shown that Ni base superalloys like HAYNES230, Co base superalloys like HAYNES188, super stainless steels like HAYNES HR-120, and stainless steels like 253MA are similar from a materials modelling point of view. They are austenitic, delivered solutioned, and precipitate secondary carbides and other brittle phases in service and during cyclic tests at elevated temperature. These new phases result in a significantly reduced RT ductility, while the high temperature ductility is at most moderately reduced. Therefore, TMF cycles, which repeatedly go down to low temperatures, see an embrittled alloy whereas LCF tests at Tmax (in the TMF cycle) do not. This suggests that the classical use of LCF data at Tmax might given non-conservative life estimates. Literature studies and materials testing have confirmed that TMF data may be well below LCF data at Tmax verifying the non-conservatism of the classical methodology. Furthermore, the cyclic life tends to decrease with decreasing Tmin in TMF tests, and IP TMF is usually more detrimental than OP TMF due to creep-fatigue interaction. While standard TMF tests are closer to reality than LCF tests, we are still not certain that they capture all detrimental effects under component cycling, and are running additional, carefully planned, TMF tests on aged specimen at low Tmin values to improve the analysis. More tests, especially biaxial IP TMF tests, will eventually be needed to get a comprehensive picture. A new TMF data backed model has, however, already shown a higher precision when compared with service experience than the classical creep-fatigue methodology which is calibrated with LCF data at Tmax. Further testing and analysis will enable us to refine the TMF model and extend it to additional ACP alloys. The main input to the TMF model is the stabilised inelastic strain range, as calculated by the constitutive model described in an earlier ASME Turbo paper, GT2002-30659.

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Miscia, Giuseppe, Vincenzo Rotondella, Andrea Baldini, Enrico Bertocchi, and Luca D’Agostino. "Aluminum Structures in Automotive: Experimental and Numerical Investigation for Advanced Crashworthiness." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51724.

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Ductility of aluminum alloys is highly used in automotive applications where crashworthiness becomes relevant. Due to its physical and mechanical properties, aluminum allows structures to be designed with good capacity to absorb energy, without increasing the overall weight of cars. In particular, high elongation allows for the conversion of a great amount of kinetic energy related to crash events in plastic deformation. If this was not the case, the energy involved during an accident could interest also the occupants, causing serious injuries. During large deformation of structures, chassis components may be subjected to failure, limiting the capacity of energy absorption. Therefore, the capability to predict the behavior of structures under crash loads becomes very important during the cars design process. Under these circumstances, finite element analysis is useful to simulate the response and to validate a project. In the last few years, prediction of materials behavior has become relevant in order to simulate in the best possible way the reaction of structures under dynamic loads. Contrary to what was expected, aluminum alloy might show anisotropic behavior after manufacturing processes. Extrusion, lamination and forging processes can modify crystallography, grains shape, precipitates and dislocations structures, affecting considerably the plastic properties. Furthermore, the failure limit strictly depends on the stress-strain state in the material during the crash event. Tensile state, shear state, compressive state and mixing states generally return different failure limits. Hence, it is indispensable to arrange a huge experimental campaign to define a thorough characterization of an aluminum alloy. Finite element (FE) codes give the possibility to include all these aspects, but several parameters need to be finely tuned. By limiting the number of tests, the present work aims at obtaining the numerical-experimental correlation of some crash absorbers during an impact. Tensile and shear specimens have been cut from the extruded parts of the chassis in 0°, 45° and 90° with respect to the extrusion direction. It is possible to define a fracture locus curve that identifies the equivalent strain limit of the aluminum alloys studied. For instance, Johnson-Cook and Bao-Wierzbicki criteria for aluminum alloys have been defined starting from a complete experimental campaign. They also give approximated analytical functions to define the entire fracture locus curve depending on the stress state. Uniaxial tensile and shear failure limits are the only ones taken into account in this work. Different hypothesis have been considered to define the rest of the fracture locus. Tuning the function parameters of the chosen criteria, a failure curve for compression, shear, tensile and mixing states have been set according to the experimental tests performed. The material card obtained has been further refined during the numerical-experimental correlation of both the samples and the crash absorbers: mesh size effects have been taken into account to assess the approximations of stress and strain into shell elements. In this work, fine mesh is only used during the initial correlation of specimens. This allows for considerably reducing the computational time of FE models studied. Acceleration signals and failures have been monitored in the crash absorbers. A high correlation between the experimental and numerical tests have validated the current methodology. Because of the few experimental tests performed on samples, it is not possible to study the exact mesh scaling effects at the beginning. Further refining is needed during the correlation of the whole component to get the right failures. In any case, the error given by the experimental dispersion could compromise the correlation and this is the reason why accuracy is not always necessary during the first phases of the correlation settings.

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Yao, M. Y., B. X. Zhou, Q. Li, W. P. Zhang, L. Zhu, L. H. Zou, J. L. Zhang, and J. C. Peng. "Effect of Bi Addition on the Corrosion Behavior of Zirconium Alloys." In 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-15460.

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In order to investigate systematically the effect of Bi addition on the corrosion resistance of zirconium alloys, different zirconium-based alloys, including Zr-4 (Zr-1.5Sn-0.2Fe-0.1Cr), S5 (Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr), T5 (Zr-0.7Sn-1.0Nb-0.3Fe-0.1Cr) and Zr-1Nb, were adopted to prepare the zirconium alloys containing Bi of 0∼0.5% in mass fraction. These alloys were denoted as Zr-4+xBi, S5+xBi, T5+xBi and Zr-1Nb+xBi, respectively. The corrosion behavior of these specimens was investigated by autoclave testing in lithiated water with 0.01 M LiOH or deionized water at 360°C/18.6 MPa and in superheated steam at 400 °C/10.3 MPa. The micro structure of the alloys was examined by TEM and the second phase particles (SPPs) were analyzed by EDS. Micro structure observation shows that the addition of Bi promotes the precipitation of Sn as second phase particles (SPPs) because Sn is in solid solution in α-Zr matrix in Zr-4, S5 and T5 alloys. The concentration of Bi dissolved in α-Zr matrix increase with the increase of Nb in the alloys, and the excess Bi precipitates as Bi-containing SPPs. The corrosion results show that the effect of Bi addition on the corrosion behavior of different zirconium-based alloys is very complicated, depending on their compositions and corrosion conditions. In the case of higher Bi concentration in α-Zr, the zirconium alloys exhibit better corrosion resistance. However, in the case of precipitation of Bi-containing SPPs, the corrosion resistance gets worse. This indicates that the solid solution of Bi in α-Zr matrix can improve the corrosion resistance, while the precipitation of the Bi-containing SPPs is harmful to the corrosion resistance.

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Ohta, Takeo, Masami Uchida, Kazumi Yoshioka, Shigeaki Furukawa, and Koichi Kotera. "Million Cycle Overwritable Phase Change Optical Disk Media." In Optical Data Storage. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/ods.1989.tua4.

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GeTe-Sb2Te3-Sb pseudo ternary components alloy shows laser induced fast crystallization speed. Increasing the Sb concentration leads to higher crystallization temperature around 180°C. Thin film disk structure of 20nm active layer produce stable bit error rate characteristics of more than million cycle over-write.

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Nonaka, Koutarou, Yasuhide Nishida, and Susumu Fujimori. "Hologram Recording by a Pulsed Method on Phase Change Media." In Optical Computing. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/optcomp.1991.me21.

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This paper presents a novel real-time hologram recording method and derives a formula for calculating the diffraction efficiency of gratings recorded in phase change media. The formula gives media parameters for high diffraction efficiency. In addition, a two-dimensional character pattern is successfully reconstructed using GeTe alloy film.

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Nieto, Zackery, V. M. Krushnarao Kotteda, Arturo Rodriguez, Sanjay Shantha Kumar, Vinod Kumar, and Arturo Bronson. "Utilization of Machine Learning to Predict the Surface Tension of Metals and Alloys." In ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83248.

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As technology progresses, predictive solutions created by computer generated algorithms are becoming more and more viable. The purpose of this study is to test the predictive capabilities and their values of three different types of predictive algorithms, a multi-variable linear regression algorithm, a nonlinear random forest model, and a TensorFlow deep learning neural network model. To compare each algorithm, we used the surface tensions of the molten pure metals, copper, bismuth, and silver, as well as the copper-bismuth, and copper silver molten alloys. The surface tensions were then compiled into data sets meant for training and testing the algorithms predictive capabilities. Throughout this study, we considered how each algorithm could be corrected in ways to increase its predictability without over-constraining the algorithm to satisfy only these data sets. At the end, it became apparent that although the predictions of each algorithm were able to get to a fairly decent accuracy, the random forest model proved to be the best and most useful algorithm for surface tensions.

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Звіти організацій з теми "GeTe alloys"

Gosnell, J. Stephen. What is Community Science, and How do I Get Involved? American Museum of Natural History, 2023. http://dx.doi.org/10.5531/cbc.ncep.0002.

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Community science allows individuals who are not professional scientists to contribute to active scientific research. In this exercise, students learn about the history and growth of community science efforts and how they connect participants to data. Defining traits of community science are discussed, along with examples and potential future directions. Students then have the opportunity to contribute as community scientists by working with projects hosted on the Zooniverse site. Follow-up questions have them reflect on this experience and relate their activity to the larger field.

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Wentworth, Jonathan, and David Rapley. Genome edited animals. Parliamentary Office of Science and Technology, November 2022. http://dx.doi.org/10.58248/pb50.

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Genome editing, also known as gene editing, encompasses a broad range of techniques that allows targeted changes in the DNA of animals (and plants). The Genetic Technology (Precision Breeding) Bill 2022 -2023, due for Second Reading in the House of Lords on 21 November 2022, intends to change the regulatory definition of certain genome-edited animals.

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Adam, Zach, and Eran Pichersky. Degradation of Abnormal Proteins in Chloroplasts of Higher Plants. United States Department of Agriculture, August 1994. http://dx.doi.org/10.32747/1994.7568768.bard.

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In this study we attempted to get a better understanding of processes involved in the degradation of abnormal proteins i chloroplasts. To achieve this goal, we used a number of complementary approaches. We first characterized the expression of the two subunits of Clp protease. We demonstrated that both of them were expressed in chloroplasts in a constitutive fashion, but the expression of the regulatory subunit ClpC was enhanced by light. We generated a mutant the lumenal protein OEE33 which was targeted to the stroma in in vitro experiments. In the wrong compartment it was found unstable, and characterization of its degradation revealed that it was degraded by a soluble, ATP-dependent serine protease, which are also the characteristics of Clp protease. In search of other homologues of bacterial proteases, we found that chloroplasts contain a homologue of the FtsH protease. It is an ATP-dependent metallo-protease, bound to the stromal side of the thylakoid membrane, whose expression is dependent on light. The gene encodig this protease was cloned and characterized. In attempt to generate Arabidopsis mutant plants impaired in their capability to degrade abnormal chloroplast proteins, we fused the gene for mistargeted OEE33 to the streptomycin-detoxifying gene. This chimeric gene was introduced into Arabodipsis plants, to generate transformed plants. This transformants plants were sensitive to streptomycin due to the rapid turn-over of the chimeric protein. Seeds from these plants were then chemically mutagenised, and seedlings were selected for their capability to grow on streptomycin. The ability of these mutant transformants to grow on streptomycin is presumably due to stabilization of the chimeric protein. These plants will allow us in the future to identify the effected genes, which are likely to be involved in the protein degradation process.

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Rodriguez, Russell J., and Stanley Freeman. Gene Expression Patterns in Plants Colonized with Pathogenic and Non-pathogenic Gene Disruption Mutants of Colletotrichum. United States Department of Agriculture, February 2009. http://dx.doi.org/10.32747/2009.7592112.bard.

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Fungal plant pathogens are responsible for extensive annual crop and revenue losses throughout the world. To better understand why fungi cause diseases, we performed gene-disruption mutagenesis on several pathogenic Colletotrichum species and demonstrated that pathogenic isolates can be converted to symbionts expressing non-pathogenic lifestyles. One group of nonpathogenic mutants confer disease protection against pathogenic species of Col!etotrichum, Fusarium and Phytophthora; drought tolerance; and growth enhancement to host plants. These mutants have been defined as mutualists and disease resistance correlates to a decrease in the time required for hosts to activate defense systems when exposed to virulent fungi. A second group of non-pathogenic mutants did not confer disease resistance and were classified as commensals. In addition, we have demonstrated that wildtype pathogenic Colletotrichum species can express non-pathogenic lifestyles, including mutualism, on plants they colonize asymptomatically. We have been using wildtype and isogenic gene disruption mutants to characterize gene expression patterns in plants colonized with a pathogen, mutualist or commensal. The US group is contrasting genes expressed during colonization by mutuahstic and commensal mutants of C. magna and a pathogenic wildtype C. coccodes on tomato. The Israeli group is characterizing genes expressed during asymptomatic colonization of tomato by wildtype C. acutatum and a non-pathogenic mutant.To accomplish this we have been utilizing suppressive subtraction hybridization, microarray and sequencing strategies. The expected contribution of this research to agriculture in the US and Israel is: 1) understanding how pathogens colonize certain hosts asymptomatic ally will shed light on the ecology of plant pathogens which has been described as a fundamental deficiency in plant pathology; 2) identifying genes involved in symbiotically conferred disease resistance will help explain why and how pathogens cause disease, and may identify new candidate targets for developing genetically modified disease resistant crop plants.

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Ohad, Nir, and Robert Fischer. Control of Fertilization-Independent Development by the FIE1 Gene. United States Department of Agriculture, August 2000. http://dx.doi.org/10.32747/2000.7575290.bard.

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A fundamental problem in biology is to understand how fertilization initiates reproductive development. During plant reproduction, one sperm cell fuses with the egg to form an embryo, whereas a second sperm cell fuses with the adjacent central cell nucleus to form the endosperm tissue that supports embryo and/or seedling development. To understand the mechanisms that initiate reproduction, we have isolated mutants of Arabidopsis that allow for replication of the central cell and subsequent endosperm development without fertilization. In this project we have cloned the MEA gene and showed that it encode a SET- domain polycomb protein. Such proteins are known to form chromatin-protein complexes that repress homeotic gene transcription and influence cell proliferation from Drosophylla to mammals. We propose a model whereby MEA and an additional polycomb protein we have cloned, FIE , function to suppress a critical aspect of early plant reproduction and endosperm development, until fertilization occurs. Using a molecular approach we were able to determine that FIE and MEA interact physically, suggesting that these proteins have been conserved also during the evolution of flowering plants. The analysis of MEA expression pattern revealed that it is an imprinted gene that displays parent-of- origin-dependent monoallelic expression specifically in the endosperm tissue. Silencing of the paternal MEA allele in the endosperm and the phenotype of mutant mea seeds support the parental conflict theory for the evolution of imprinting in plants and mammals. These results contribute new information on the initiation of endosperm development and provide a unique entry point to study asexual reproduction and apomixis which is expected to improve crop production.

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Ків, Арнольд Юхимович, Володимир Миколайович Соловйов та Sergey A. Tomilin. Formation of Si precipitates іn neutron irradiated Al. Видавничий відділ КДПУ, 2001. http://dx.doi.org/10.31812/0564/1027.

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Transmutation reactions are the unique way to get a large concentration of Silicon atoms in Aluminum lattice, and just in substitutional positions. Appearing Silicon atoms in Aluminum lattice instead of Aluminum atoms leads to arising of mechanical stresses. This factor is the keystone of the model, which allows to explain the main peculiarities of Si precipitate creation in Aluminum irradiated by thermal neutrons. First, we shall describe the qualitative peculiarities of the model. Then we shall perform some quantitative estimates. At last the model will be discussed and compared with experimental data.

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Schaffer, Arthur A., and Jocelyn Rose. Understanding Cuticle Development in Tomato through the Study of Novel Germplasm with Malformed Cuticles. United States Department of Agriculture, June 2013. http://dx.doi.org/10.32747/2013.7593401.bard.

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Plant cuticle development and metabolism are still poorly understood, partly due to the chemical complexity of the cuticular layer. The overall research objective was to broaden and deepen our understanding of tomato fruit cuticle development by analyzing novel germplasm with cuticular malformations and by studying the transcriptome and proteome of the fruit epidermal tissues, as strategies to overcome the challenges posed by the recalcitrance of the biological system. During the project we succeeded in identifying two genes with major impact on cuticle development. One of these encoded the first cutin synthase to be identified in plants, a metabolic step that had been a black box in cutin synthesis. In addition genes controlling the triterpenoid components of the cuticle were identified and, most interestingly, genetic variability for this component was identified among the wild tomato species germplasm. Additional germplasm was developed based on interspecific crosses that will allow for the future characterization of modifier genes that interact with the microfissuring gene (CWP) to promote or inhibit fruit cracking. One of the major accomplishments of the joint project was the integrated transcriptomic and proteomic analysis of the fruit cuticle and underlying tissues which allows for the identification of the pericarp cell layers responsible for the extracellular, cuticle-localized protein component. The results of the project have expanded our understanding of tomato fruit cuticle development and its genetic control. In addition, germplasm developed will be useful in developing tomato varieties resistant to cracking, on the one hand, and varieties useful for the dehydration industry on the other.

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Stern, David B., and Gadi Schuster. Manipulation of Gene Expression in the Chloroplast: Control of mRNA Stability and Transcription Termination. United States Department of Agriculture, December 1993. http://dx.doi.org/10.32747/1993.7568750.bard.

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Chloroplasts are the site of photosynthesis and of other essential biosynthetic activities in plant cells. Chloroplasts are semi-autonomous organelles, since they contain their own genomes and protein biosynthetic machinery, but depend on the coordinate expression of nuclear genes to assemble macromolecular complexes. The bioeingineering of plants requires manipulation of chloroplast gene expression, and thus a knowledge of the molecular mechanisms that modulate mRNA and protein production. In this proposal the heterotrophic green alga Chlamydomonas reinhardtii has been used as a model system to understand the control and interrelationships between transcription termination, mRNA 3' end processing and mRNA stability in chloroplasts. Chlamydomonas is a unique and ideal system in which to address these issues, because the chloroplast can be easily manipulated by genetic transformation techniques. This research uncovered new and important information on chloroplast mRNA 3' end formation and mRNA stability. In particular, the 3' untranslated regions of chloroplast mRNAs were shown not to be efficient transcription terminators. The endonucleolytic site in the 3' untranslated region was characterized by site directed mutagensis and the role of several 3' untranslated regions in modulating RNA stability and translation has been studied. This information will allow us to experimentally manipulate the expression of chloroplast genes in vivo by post-transcriptional mechanisms, and should be widely applicable to other higher plant systems.

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Furman, Alex, Jan Hopmans, Shmuel Assouline, Jirka Simunek, and Jim Richards. Soil Environmental Effects on Root Growth and Uptake Dynamics for Irrigated Systems. United States Department of Agriculture, February 2011. http://dx.doi.org/10.32747/2011.7592118.bard.

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Root water uptake is perhaps the most important unknown in the mass balance of hydrological and agricultural systems. The understanding and the ability to predict root uptake and the way it is influence by environmental conditions has great potential in increasing water and fertilizer use efficiency and allowing better control of water and contaminant leach towards groundwater. This BARD supported research is composed of several components, including a) intensive laboratory work for the quantification of root uptake and the way it is controlled by environmental conditions; b) development of tools for laboratory and field use that can help in sensing very low water fluxes and water content, which is a necessity for studying root uptake; c) development of capabilities to model compensated root uptake; and d) development of a database that will allow calibration of such a model. In addition some auxiliary research was performed as reported later. Some of the components, and especially the modeling and the HPP development, were completed in the framework of the project and even published in the international literature. The completed components provide a modeling environment that allows testing root compensated uptake modeling, a tool that is extremely important for true mechanistic understanding of root uptake and irrigation design that is based on mechanistic and not partially based myth. The new button HPP provides extended level of utilization of this important tool. As discussed below, other components did not get to maturity stage during the period of the project, but comprehensive datasets were collected and will be analyzed in the near future. A comprehensive dataset of high temporal and spatial resolution water contents for two different setups was recorded and should allow us understanding f the uptake at these fine resolutions. Additional important information about root growth dynamics and its dependence in environmental conditions was achieved in both Israel and the US. Overall, this BARD supported project provided insight on many important phenomena related to root uptake and to high resolution monitoring in the vadose zone. Although perhaps not to the level that we initially hoped for, we achieved better understanding of the related processes, better modeling capabilities, and better datasets that will allow continuation of this effort in the near future.

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Shani, Moshe, and C. P. Emerson. Genetic Manipulation of the Adipose Tissue via Transgenesis. United States Department of Agriculture, April 1995. http://dx.doi.org/10.32747/1995.7604929.bard.

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The long term goal of this study was to reduce caloric and fat content of beef and other red meats by means of genetic modification of the animal such that fat would not be accumulated. This was attempted by introducing into the germ line myogenic regulatory genes that would convert fat tissue to skeletal muscle. We first determined the consequences of ectopic expression of the myogenic regulatory gene MyoD1. It was found that deregulation of MyoD1 did not result in ectopic skeletal muscle formation but rather led to embryonic lethalities, probably due to its role in the control of the cell cycle. This indicated that MyoD1 should be placed under stringent control to allow survival. Embryonic lethalities were also observed when the regulatory elements of the adipose-specific gene adipsin directed the expression of MyoD1 or myogenin cDNAs, suggesting that these sequences are probably not strong enough to confer tissue specificity. To determine the specificity of the control elements of another fat specific gene (adipocyte protein 2-aP2), we fused them to the bacterial b-galactosidase reporter gene and established stable transgenic strains. The expression of the reporter gene in none of the strains was adipose specific. Each strain displayed a unique pattern of expression in various cell lineages. Most exciting results were obtained in a transgenic strain in which cells migrating from the ventro-lateral edge of the dermomyotome of developing somites to populate the limb buds with myoblasts were specifically stained for lacZ. Since the control sequences of the adipsin or aP2 genes did not confer fat specificity in transgenic mice we have taken both molecular and genetic approaches as an initial effort to identify genes important in the conversion of a multipotential cell such as C3H10T1/2 cell to adipoblast. Several novel adipocyte cell lines have been established that differ in the expression of transcription factors of the C/EBP family known to be markers for adipocyte differentiation. These studies revealed that one of the genetic programming changes which occur during 10T1/2 conversion from multipotential cell to a committed adipoblast is the ability to linduce C/EBPa gene expression. It is expected that further analysis of this gene would identify elements which regulate this lineage-specific expression. Such elements might be good candidates in future attempts to convert adipoblasts to skeletal muscle cells in vivo.

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