Academic literature on the topic 'Valence du Ni'
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Journal articles on the topic "Valence du Ni"
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KUMARI, KAMLESH, R. K. SINGHAL, K. B. GARG, et al. "A COMPREHENSIVE STUDY OF THE ELECTRONIC STRUCTURE OF BOROCARBIDES BY XPS TECHNIQUE." International Journal of Modern Physics B 17, no. 03 (2003): 361–71. http://dx.doi.org/10.1142/s0217979203015772.
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Polycrystalline samples of YNi 2 B 2 C and magnetic ErNi 2 B 2 C prepared by arc melting technique have been investigated. Resistivity and magnetization measurements yield superconducting transition temperatures for the two samples of ~ 15 K and ~ 11 K respectively. Core level spectroscopic studies on C (1s), B (1s), Ni (2p), Er (4d) and Y (3d) as well as valence band measurements were performed in order to investigate the electronic structure. The results are interpreted to deduce the valence of Y, Er and Ni. Ni is found to exist in 2+ and y in 3+ valence state. The Er spectra indicate that Er may either be in an intermediate valence state or some minor impurity phase.
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Hsu, Li-Shing, K. L. Tsang, and S. C. Chung. "Resonant Valence-Band Satellites at the Ni-3p Edge of Ni3Al, Ni3Ga and Ni3In." International Journal of Modern Physics B 12, no. 26 (1998): 2757–67. http://dx.doi.org/10.1142/s0217979298001605.
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Valence-band photoemission sspectra of Ni 3 Al , Ni 3 Ga and Ni 3 In were measured with synchrotron radiation at photon energies around the Ni-3p core excitation threshold. The valence-band satellites are resonantly enhanced. The number of holes per Ni atom in the Ni-d band for Ni 3 Al , Ni 3 Ga and Ni 3 In is estimated to be 0.37, 0.30 and 0.34, respectively. The self-energy correction due to the configuration interaction is 0.72, 0.71 and 0.72 eV, respectively, for Ni 3 Al , Ni 3 Ga and Ni 3 In . The Fano parameters and the effective Coulomb interactions between two 3D holes for these intermetallic compounds are determined.
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Hacisalihoglu, M. Y., L. Tortora, G. Tomassucci, L. Simonelli, and N. L. Saini. "Anisotropic Local Structure of SrFe2−xNixAs2 (x = 0.00, 0.16, and 0.23) Superconductor Probed by Polarized X-ray Absorption Fine Structure Measurements." Materials 17, no. 6 (2024): 1301. http://dx.doi.org/10.3390/ma17061301.
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We have investigated the effect of the Ni substitution on the local structure and the valence electronic states of the SrFe2−xNixAs2 (x = 0.00, 0.16, and 0.23) superconductor with a multi-edge extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopy. The As K-edge and Fe K-edge EXAFS measurements in the two polarizations (E‖ab and E‖c) show a clear change in the local structure with Ni concentration. The near-neighbor bondlengths and the related mean-square relative displacements (MSRDs) decrease as the Ni content increases. The polarized XANES spectra at the As, Fe and Ni K edges reveal a systematic change in the anisotropy of the valence electronic structure. The results suggest that the quasi 2D electronic structure of this system tends to become more isotropic as the Ni content increases. The local structure and the valence electronic states are discussed in the frame of the evolving electronic transport of the SrFe2−xNixAs2 system.
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Liqing, Chen, Liu Zuqin, and Zhang Wei. "Valence state analysis of elements by EPMA and its application." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (1990): 230–31. http://dx.doi.org/10.1017/s0424820100134752.
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Valence state analyses of Fe and Mn in oxides by EPMA have been reported in literature. In this paper, the effects of valence state on intensity ratios ILα/IKα and ILα/ILβ of Cu, Ni, Co, Fe, Mn, Cr and their oxides, and on intensity ratios ILβ2/ILα1 and ILγ1/ILα1 of Mo, Nb, Zr and their oxides were studied. It was observed that intensity ratios change with valence states in accordance with some regularities, and these effects could be utilized for analyzing the valence states of catalysts.Valence state analysis of elements by EPMA is based on the fact that changes in the states of valence electrons in the outer shells of an atom cause corresponding changes in line intensities. The M electrons of Cu, Ni, Co, Fe, Mn, Cr and the N electrons of Mo, Nb, Zr are valence electrons. Line Kα1,2 and six lines of L are produced from the transitions of K-L2,3 and L-M or L-N respectively.
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Hatakeyama, Makoto, Yuki Sakamoto, Koji Ogata, et al. "A study on an unusual SN2 mechanism in the methylation of benzyne through nickel-complexation." Phys. Chem. Chem. Phys. 19, no. 39 (2017): 26926–33. http://dx.doi.org/10.1039/c7cp04739h.
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D'Souza, S. W., R. S. Dhaka, Abhishek Rai, et al. "Surface Study of Ni2MnGa(100)." Materials Science Forum 684 (May 2011): 215–30. http://dx.doi.org/10.4028/www.scientific.net/msf.684.215.
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The (100) surface of Ni2MnGa ferromagnetic shape memory alloy exhibits intrinsic surface property dissimilar to the bulk as well as influence of compositional variation at the surface. It is shown that by sputtering at room temperature and annealing at high temperature, it is possible to obtain a clean, ordered and stoichiometric surface. However, for even higher annealing temperatures, the surface becomes Mn rich. The (100) surface of Ni2MnGa is found to have Mn–Ga termination. A surface reconstruction to p4gm symmetry is observed in the austenite phase, while the expected bulk truncated symmetry at surface is p4mm. For the stoichiometric surface, the XPS valence band is compared with our calculations based on first principles density functional theory and good agreement is obtained. The ultraviolet photoelectron spectroscopy (UPS) valence band spectra depend sensitively on composition varying from Ni rich to Mn rich surfaces. A satellite feature observed in both Ni 2p core-level and valence band spectra is related to the narrow 3d valence band in Ni2MnGa.
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Vereshchagin, Oleg, Olga Frank-Kamenetskaya, and Ira Rozhdestvenskaya. "Bond valence constraints on the composition of 3d-elements bearing tourmalines." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C1118. http://dx.doi.org/10.1107/s2053273314088810.
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F.C. Hawthorne (2002) and F. Bosi (2011) showed that bond valence approach is to be applied to stability prediction of tourmaline structure with different chemical composition. Using this approach we considered bond valence constraints on occupation of Y, Z, V and W sites of Cu-, Ni-bearing tourmalines. From the standpoint of the bond valence approach, [3YW] unit is unstable if W site is fully occupied by O2-. The stability of [3YW] unit decreases along a row: 3 divalent cations → 2 divalent cations + 1 trivalent cation → 2 trivalent cation + 1 divalent cations → 3 trivalent cations if W site is fully occupied by OH- or F-. There is no limitation on 3d elements and aluminum content in [2ZYV] if V site is fully occupied by OH-. The [2ZYV] unit is unstable if V site is fully occupied by O2-. The data, obtained from calculation of bond valences are in a good agreement with results of single crystal structure refinements of synthetic Cu- (Ertl et al., 2013) and Ni-tourmalines: Cu-bearing olenite with a CuO content of 8.39 wt.% [a = 15.849(1), c =7.087(1) Å, R = 2.5%] and Ni-bearing olenite with a NiO content of 18.96 wt.% [a = 15.890(2), c = 7.1815(8), R = 3.1%]. In all cases W and V sites are predominantly occupied by OH- anions. The composition of [3YW] units are [(Cu1.80Al1.20)(OH)0.60F0.40] and [(Ni1.80Al1.20)(OH)1.00]. Breaking of charge balance with increasing of bivalent cations is maintained by increasing of portion of vacancies at X site and increasing of content of trivalent cations (Al, B) at T site.
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HAGIWARA, M., and K. KATSUMATA. "OBSERVATION OF FRACTIONAL SPIN DEGREES OF FREEDOM IN AN S=1 LINEAR CHAIN HEISENBERG ANTIFERROMAGNET." Modern Physics Letters B 05, no. 11 (1991): 741–46. http://dx.doi.org/10.1142/s0217984991000915.
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We have studied the typical spin one linear chain Heisenberg antiferromagnet, Ni ( C 2 H 8 N 2)2 NO 2( ClO 4) containing a small amount of Cu2+ by electron spin resonance (ESR) technique. The ESR results are successfully explained by the model that the valence bonds in the valence bond solid state are broken at the Cu 2+ sites resulting in fractional spin degrees of freedom at the Ni 2+ sites neighboring the Cu 2+.
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MUN, B. S., M. WATANABE, M. ROSSI, V. STAMENKOVIC, N. M. MARKOVIC, and P. N. ROSS. "THE STUDY OF SURFACE SEGREGATION, STRUCTURE, AND VALENCE BAND DENSITY OF STATES OF Pt3Ni(100), (110), AND (111) CRYSTALS." Surface Review and Letters 13, no. 05 (2006): 697–702. http://dx.doi.org/10.1142/s0218625x06008682.
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The surface segregation, structure, and valence band density of states of Pt 3 Ni (100), (110), and (111) single crystals are characterized with low energy ion scattering (LEIS), low energy electron diffraction (LEED), and ultraviolet photoemission spectroscopy (UPS). The results of LEIS clearly reveal the complete surface segregation of Pt to the top layer on all crystal alloys. LEED indicates the (5 × 1) surface reconstruction on the Pt 3 Ni (100), while (110) and (111) surfaces show (2 × 1) and (1 × 1) patterns, respectively, identical to Pt single crystals. The valence bands density of states on Pt 3 Ni alloys are compared to those of Pt single crystals via UPS measurements.
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Wang, Shuli, Xudong Yang, Zong Liu, Dawen Yang, and Ligang Feng. "Efficient nanointerface hybridization in a nickel/cobalt oxide nanorod bundle structure for urea electrolysis." Nanoscale 12, no. 19 (2020): 10827–33. http://dx.doi.org/10.1039/d0nr01386b.
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Efficient Ni valence state synergism was found active in the electrocatalysis reaction, resulting from the crystal lattice hybridization in the interface of Ni/Co oxide nanoparticles assembled as a nanorod bundle structure.
Dissertations / Theses on the topic "Valence du Ni"
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BARBEY, LAURENCE. "Oxydes a valence mixte des systemes cu, fe, ni, co. Structures et proprietes magnetiques." Caen, 1994. http://www.theses.fr/1994CAEN2039.
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Les proprietes magnetiques et structurales des oxydes de cuivre ybaco#2##xcu#xo#5 et ybacocu#1##xfe#xo#5, de structure type 112, ont ete etudiees. L'influence des elements co#2#+, co#3#+, cu#2#+ et fe#3#+ sur le magnetisme de ces phases a ete mise en evidence grace aux etudes par diffraction neutronique, par spectroscopie mossbauer et grace a des mesures de susceptibilite magnetique. Une correlation entre la distorsion des pyramides et l'orientation des spins de ces elements, determinee par diffraction neutronique, a ainsi ete etablie. Dans ces phases, le co#3#+ adopte la configuration electronique s=1. Les phases eubaco#2##xcu#xo#5#+#d ont ete isolees mais l'ecart a la stchiometrie en o#5 reste important. La presence d'oxygene supplementaire localise dans les couches d'europium parait conditionner le comportement magnetique a propos duquel certaines hypotheses, basees sur les seules mesures de susceptibilite entreprises, ont ete avancees. De plus, dans le systeme euba(co, cu)o, une nouvelle phase d'intercroissance des structures 112 et 123, de formulation eu#2#,#5ba#2#,#5co#2cu#3o#1#2 a ete synthetisee; une etude par diffraction de rayons x et par microscopie electronique a permis de la decrire. D'autre part, la substitution d'une partie du cuivre par du nickel, couplee a celle du neodyme par un alcalino-terreux a (a=sr, ba, ca) dans la structure nd#2bacuo#5 entraine la formation d'une phase a valence mixte isotype de cette phase; ce qui implique une coordination inusuelle plan-carre du ni. L'influence des ions nd#3#+ sur la susceptibilite magnetique a ete mise en evidence. Enfin, la structure d'une phase nouvelle, de formulation nd#2ba#4cu#2o#9 a ete resolue grace a la microscopie electronique et par diffraction des rayons x. Cette nouvelle structure consiste en des chaines isolees de pyramides cuo#5 jointes par les sommets dont la cohesion est assuree par des ions nd#3#+ et ba#2#+
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Wieling, Sönke. "Besetzte und unbesetzte elektronische Struktur von geordneten Dünnschichtverbindungen der Seltenen Erden Eu und Yb mit den Übergangsmetallen Pd und Ni." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2003. http://nbn-resolving.de/urn:nbn:de:swb:14-1064490965781-71077.
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The present thesis deals with the occupied and unoccupied electronic states of intermetallic compounds of the rare-earth metals (RE) Eu and Yb with the transition metals Pd and Ni. The compounds were prepared in-situ as epitaxial thin films on single-crystalline substrates. For comparison, the experiments were extended to a Ba/Pd compound, which was prepared in the same way. All samples were characterised by low-energy electron diffraction (LEED), photoelectron spectroscopy (PES) and inverse photoemission (IPE). For the IPE experiments an appropriate spectrometer was built. It consists of a combination of a toroidal-grating and a crystal monochromator and enables experiments with photon energies in the range of 10-25 eV and at 1486.6 eV. LEED experiments reveal the formation of a AuCu3 structure with a (111) surface orientation for RE/Pd systems, while the formation of a CaCu5-structure with (0001) surface orientation for the Ba/Pd and Eu/Ni compounds was found. The Eu compounds show a surface-valence transition from the trivalent to the divalent configuration. An ordered overstructure is formed at the surface despite an increase of the ionic volume of Eu by about 40 %. The measured electronic structure is in good accordance with results of local-density-approximation band-structure calculations<br>In der vorliegenden Dissertation werden die besetzten und unbesetzten elektronischen Zustände intermetallischer Verbindungen der Seltenen Erden (SE) Eu und Yb mit den Übergangsmetallen Pd und Ni betrachtet. Die Verbindungen wurden als epitaktische Dünnschichten in-situ auf einkristallinen Substraten präpariert und mittels niederenergetischer Elektronenbeugung (LEED), Photoelektronenspektroskopie (PES) und inverser Photoemission (IPE) charakterisiert. Zu Vergleichszwecken wurde die Untersuchung zusätzlich auf eine auf gleiche Weise präparierte Ba/Pd-Verbindung ausgedehnt. Für die Durchführung der IPE-Experimente wurde ein entsprechendes Spektrometer aufgebaut. Die Kombination aus einem Toroidgitter- und einem Kristallmonochromator ermöglicht wahlweise Experimente im Photonenenergiebereich von 10-25 eV und bei 1486,6 eV. Die Analysen der LEED-Daten ergaben für die SE/Pd-Systeme die Bildung der AuCu3-Struktur mit einer (111)-Oberflächenorientierung, für die Ba/Pd- und die Eu/Ni-Verbindungen die der CaCu5-Struktur mit (0001)&quot;=Oberflächenorientierung. Die Eu-Verbindungen zeigen dabei Oberflächenvalenzübergänge von der drei- zu der zweiwertigen Konfiguration mit Ausbildung geordneter Überstrukturen an der Oberfläche trotz einer 40 prozentigen Zunahme des Eu-Ionenvolumens. Die beobachtete elektronische Struktur stimmt gut mit den Ergebnissen von Bandstrukturrechnungen in der lokalen Dichtenäherung überein
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Dahab, Hassan-Dahab. "Synthèse, cristallochimie et propriétés physiques de nickelates de terre rare (La, Nd) de structure dérivée de la perovskite à degré d’oxydation inusuel." Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0047.
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Ces travaux qui s’inscrivent dans le cadre d’une collaboration entre l’ICMCB et l’institut Néel portent sur les nickelates (RE1-xSrxNiO2 ou RE = La et Nd) sous forme de poudres. Dans le cadre de cette thèse je présente la synthèse et design chimique de ces nouveaux matériaux par voie chimique innovante, incluant la chimie douce (voie citrate – nitrate), la synthèse sous haute pression d’oxygène (PO2 < 650 bars) (phases RENiO3) à haute température (T = 900°C) et enfin la réduction topochimique utilisant l’hydrure de calcium CaH2 à basse température (T<300°C), dans le but de stabiliser le Ni(+I) dans un environnement plan carré (RENiO2). La caractérisation physico-chimique des composés synthétisés, via les rayons X et de la microscopie électronique couplée à une sonde EDX a mis en évidence une limitation intrinsèque de la solubilité du Sr. Ensuite, nous avons étudié les propriétés physiques intrinsèques des matériaux synthétisés, par différentes techniques de laboratoire, telles que des mesures de transport électrique, de chaleur spécifique et de susceptibilité magnétique, mais aussi des mesures complémentaires qui font appel aux grands instruments : DRX sous pression physique (ESRF), diffusion élastique et inélastique de neutrons (ILL, ISIS, étude des excitations et ordre magnétique). Nous avons établi le schéma de champ cristallin et la possible présence d’un ordre magnétique intrinsèque à NdNiO2 et Nd1-xSrxNiO2. Enfin de nouvelles phases de type RENiO2.5 ont été stabilisées. Une structure cristalline originale qui stabilise trois états de valence du nickel a été proposée pour le composé NdNiO2.5. Ce dernier présente un ordre ferrimagnétique autour de 270 K<br>This work, which is part of a collaboration between the ICMCB and the Néel Institute, focuses on nickelates (RE1-xSrxNiO2 or RE = La and Nd) in the form of powder (bulk samples). Within this thesis, I present the synthesis and chemical design of these new materials using an innovative chemical route, including soft chemistry (citrate – nitrate route), synthesis under high oxygen pressure (PO2 < 650 bars) (RENiO3 phases) at high temperature (T = 900°C) and finally topochemical reduction using calcium hydride CaH2 at low temperature (T<300°C), with the aim of stabilizing Ni(+I) in a square planar environment (RENiO2). The physicochemical characterization of the as-synthetized compounds via laboratory X-ray diffraction and electron microscopy coupled to an EDX probe evidenced an intrinsic solubility limit of the Sr atoms. We then studied the intrinsic physical properties of the synthesized materials, not only by different laboratory techniques, such as electrical transport measurements, specific heat and magnetic susceptibility, but also using complementary measurements in large scale facilities instruments: XRD under physical pressure at the ESRF, elastic and inelastic neutron diffraction at the ILL and at ISIS for the study of magnetic excitations and magnetic order. We have established the crystal field diagram and the possible presence of an intrinsic magnetic order in NdNiO2 and Nd1-xSrxNiO2. Finally, new phases of the RENiO2.5 type have been synthetized. An original crystal structure that stabilizes three valence states of nickel has been proposed for the compound NdNiO2.5. The latter presents a ferrimagnetic order around 270 K
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Cushman, Christopher Scott. "Destruction of chlorinated hydrocarbons by zero-valent zinc and bimetallic zinc reductants in bench-scale investigations." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1398342299.
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Pan, WenLih, and 潘文立. "Crystalline Structure, Mixed Valence States, and Magnetic Behavior in Single Crystalline Fe-Ni-O Thin Films." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/22201701488253251244.
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碩士<br>國立中正大學<br>物理系<br>92<br>In order to understand the structural transformation of the Fe - Ni - O mixture film formations, we use (MBE) molecular beam epitaxy to generate a series of Fe Ni O on MgO(001) substrate. During it’s developing process, we maintain its temperature at 250 0C and film in 1000 thickness. Regarding the film measurement, we use the x-ray diffraction instrument to measure the film’s crystal lattice constant transformation. We also use x-ray absorption spectroscopy to measure film’s electronic structure,and VSM to measure the film’s magnetic. Our laboratorial measurement research shows that mixture film Fe Ni O when X=0~0.71, its magnetic and oxide electric structure, is quite similar to Fe O ; both are spinel structure. However, when X=0.8~1,the film’s magnetic disappears and it’s oxide electric structures is also quite similar to NiO; both are rocksalt structure. Therefore, we would like to suppose that when X=0.71~0.8, the film’s structure transformed. Also, we may conclude the following assumption: the stability of crystal structure is related to the structure’s ion mixture valence and ion’s radius.
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Hesse, Hans-Josef. "Hochdruckuntersuchungen zur Eu-Valenz in intermetallischen EuM2Ge2-Systemen (M = Ni, Pd, Pt) /." 1997. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=007747511&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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張吉辰. "The study of decoloration of azo dye Acid Blue 113 wastewater using nanoscale zero-valent iron and Fe/Ni and Fe/Zn." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/85602084392761210663.
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碩士<br>弘光科技大學<br>環境工程研究所<br>97<br>In general, effluents discharged from dye manufacturing and industries with strong color and high level of chemical oxygen demand (COD) which can not meet the stricter Taiwan’s Nation Effluent Standard by convention wasterwater treatment system. Thus, it demands urgently to develop an economic and effective technique for increase of color removal of wastewater treatment efficiency and time-saving operation. This study proposed decoloration of azo dye Acid Blue 113 wastewater using nanoscale zero-valent iron (NZVI) and bimetal Fe/Ni, Fe/Zn by considering the operating conditions such as reaction time, metal dosage, initial dye concentration, bimetal ratio and nanomaterials durable test. Moreover, NZVI was conneted with UV/H2O2 process for enhancement of TOC mineralization as well as the operating time and cost effectiveness. The experimental results demonstrated efficient decolorization by NZVI, however, gradual oxidized of NZVI reduce the color removal. Thus, bimetal Fe/Ni and Fe/Zn were employed to avoid easy oxidation of iron. From the duration test results, they were better than that of NZVI. Besides, NZVI was capable to decolorize the dye wastewater but insignificant for TOC removal so that initial NZVI addition 30 minutes for color removal in connection with UV/H2O2 process for TOC removal were conducted. The results showed color and TOC removal efficiency were 96.24 and 11.81% by NZVI addition during initial 30 minutes, respectively, while 99.63 and 92.68%, respectively by the following UV/H2O2 process till 120 minutes. Therefore, the connection of NZVI and UV/H2O2 process was proved to be a high feasible technology to obtain color removal as well as TOC removal.
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Cloutier, Jean-Philippe. "Complexes NCN de Ni(II) et Ni(III) : synthèse, caractérisation et rôle dans le mécanisme de couplage C-O, C-N et C-halogènes." Thèse, 2018. http://hdl.handle.net/1866/21694.
Full textBooks on the topic "Valence du Ni"
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editor, Reyero Carlos, ed. Ni clásicos ni modernos: Buscando la verdad en el Museo de Bellas Artes de València. Generalitat Valenciana, 2020.
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Félix, Báez-Jorge. Olor de santidad: San Rafael Guízar y Valencia: articulaciones históricas, políticas y simbólicas de una devoción popular. Universidad Veracruzana, 2006. http://dx.doi.org/10.25009/uv.282.1401.
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Esta obra nos introduce a las articulaciones históricas, políticas y simbólicas de una devoción popular: la que se dedica a Rafael Guízar y Valencia, y constituye la esperada biografía de este varón al que por muchos años se tuvo por santo y que terminó siendo canonizado. Sin embargo Báez-Jorge no se detiene ni es limitado por la fama de santidad, sino que busca lo que tuvo de ser de carne y hueso.
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Baltasar Rull Villar, Alcalde de Valencia (1951-1955): "ni lo he solicitado ni lo he apetecido", la Valencia de los años cincuenta. B. Torralba, 2015.
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Ni contigo ni sin ti: Socialismo y republicanismo histórico en la Valencia de los años treinta. Institució Alfons el Magnànim, 2015.
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Fortich-Navarro, Mónica Patricia. La mujer del porvenir : Concepción Arenal Ponte. Universidad Libre Sede Principal, 2022. http://dx.doi.org/10.18041/978-958-5578-95-1.
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Concepción Arenal Ponte (Ferrol, España, enero 31 de 1820-Vigo, España, 4 de febrero de 1893). Abogada, poeta, ensayista y periodista cuya obra se inscribe dentro del Realismo literario, es precursora del feminismo español con sus escritos y acciones sociales en defensa de los derechos y la dignidad de las mujeres. No es difícil imaginar las angustias de su tiempo. La literatura nos da la licencia, lo que siguen son los detalles de vida, los lugares, las personas. Primero una biblioteca y el contacto con los libros, luego el plan, las injusticias y carencias de muchas mujeres y el ritual de la limitación ya estaba servido. Doña Concepción “Concha” como talvez la llamaban sus seres queridos, ya se había organizado muchas veces un plan mental. Debía ingresar a las Aulas de la Facultad de Derecho de la Universidad Central de Madrid. Con seguridad se había detenido en las proximidades del alma mater, había visto los rostros adustos de los juristas, sus cerrados trajes de levita y sombrero de copa alta. El siglo XIX seguía la férrea tradición y resistencia a que la mujer tuviera un espacio fuera de sus roles reproductivos. Tuvo que haber examinado con detalle propio de su alma sensible los gestos, los adornos, el brillo de las miradas, las inflexiones de la voz, los zapatos lustrosos, el espíritu de cofradía de los estudiantes en las llegadas y salidas masivas del claustro. Habría sabido el arte de camuflarse en la muchedumbre, en las jornadas más concurridas, el discreto arte de hacerse uno con la mayoría. Concepción también había estudiado su propia puesta en escena. Frente al espejo habría repetido algunos latinazgos, y un poema clásico propio de la retórica de la época. La oratoria en preparación para el examen de admisión mientras soñaba con ser como “uno más” en el aula de clases de derecho civil o la teoría del poder y del Estado. Aunque no tengamos los datos certeros de un biógrafo, con seguridad tuvo largas charlas preparatorias para el gran día, el resto de la puesta en escena. Con seguridad esa cómplice ayuda amiga que es-tuvo a su lado cuando fue descubierta. Siendo consciente de las limitaciones de su tiempo ella pensaba en ser parte del cambio. No es posible concebir su proyecto, como una mera apuesta por romper barreras sin conciencia de futuro. Sin duda aprender leyes era proporcional a su pasión por la justicia, la de los más desvalidos, entre quienes se contaba ella misma y su género. Su candidez o exceso de confianza sorprenden. Las jornadas de práctica teatral habían terminado por forjar en ella un camuflaje seguro, una performance donde la masculinidad se completa en el travestimiento, en un final de siglo donde los estereotipos de la masculinidad eran tan marcados que un poco de brusquedad, unas facciones duras, ante la ausencia de maquillaje o el cabello corto y engominado habían bastado para completar la expectativa de género. En el proceso todo valía la pena frente a un fin elevado: las leyes y con ella la justicia que debía estar al servicio de la causa social. Concepción Arenal no es la primera mujer que se viste de hombre para alcanzar su sueño, sí, la primera en hacerlo en una nación y en el marco de un cultura jurídica ítalo- germánico-canónica, en la que el lugar de la mujer en la sociedad estaba limitado por una visión patriarcal, una línea paterna de mando y organización de la vida en la que las mujeres no tienen derechos civi les, ni políticos, esencialmente porque no eran personas y mucho menos ciudadanas. Sería la primera mujer española en planear y ejecutar su acceso a la educación superior, hacerse abogada a pesar de todos los obstáculos que le sobrevendrían después de ser descubierta. Triunfo a medias? No fue expulsada, su valor se leyó como un signo excepcional. Podría asistir a las aulas cumpliendo el lastimero ritual de ser recibida por un lebrel, conducida de clase en clase por cada maestro y dejada nuevamente en un espacio seguro del contacto masculino. Una semana, un mes, un año, estuvo en las aulas de 1842 a 1845, para que al final no tuviera un título formal. Concepción no se dio por vencida, no se detuvo. La historia de su éxito posterior, es el testimonio de sus libros. Su lucidez y buen juicio se extenderían tanto como sus obras. Estuvo en las cárceles y hospicios, es-cuchó el clamor de los marginados. Ella pensó en superarse, en abierta lucha contra la injusticia y luego habló, interpeló a las mujeres y hombres de su tiempo, pero sobre todo y como se titula esta obra, escribió para “la mujer del porvenir”. Su voz sigue vigente, ahora como antes y su legado constituye un acto de memoria urgen-te para esta y las futuras generaciones. *** La obra de Concepción Arenal inaugura el proyecto BLA Biblioteca de Autoras libres, en el marco de la creación del “Observatorio Mujer, género y violencias” de la Univesidad Libre, mediante Res. 03 de 20 de agosto de 2020 y en cumplimiento de sus actividades de Investigación, formación académica y proyección social, en armonía con los proyectos de investigación “Género, derecho y memoria histórica”, del grupo Derecho, Sociedad y estudios internacionales, y el proyecto mul-ticampus “Identificación los roles y los estereotipos de género en la Universidad y Comunidades de Impacto: Herramientas para Igualdad y Eliminación de todas las formas de Violencia (2021-2022)”. La colección “Biblioteca de Autoras libres” se presenta como un espacio para la difusión del pensamiento y obras de mujeres quienes, a lo largo de la historia y la formación del pensamiento político, jurídico liberal que han sido piezas clave para la construcción de una sociedad más justa, tolerante, incluyente y en paz. Finalmente, es muy importante destacar cómo ejercicio de memoria para el futuro, el trabajo de transcripción y revisión de ediciones previas, realizado por de los integrantes del semillero “Género, derecho y memoria histórica”: Jorge Acevedo, María José Nieto, Lina Moreno, Julieth Guerrero, Laura Ocampo, Valen-tina Rodríguez, Vanessa Lesmes, María Fernanda Neira y Paula Cárdenas. Sin su paciente labor de copistas, al más tradicional estilo antiguo, la colección “Biblioteca de Autoras Libres BAL” no empezaría a dar sus frutos. El proyecto BAL es una realidad gracias a la confianza y apoyo de nuestras directivas Seccionales, Dr Fernando Salinas y Dra Elizabeth García, quienes valorando la filosofía y los principios fundacionales de nuestra alma mater, acompañan este acto de memoria de mujeres que han sido una pieza fundamental en la consolidación de tradición liberal y en la igualdad de género como una necesidad urgente para la construcción de una nueva nación.
Book chapters on the topic "Valence du Ni"
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Ammarguellat, C., C. Godart, P. Haen, and G. Krill. "Physical Properties of CeM2Si2 (M = Mn, Fe, Co, Ni, Cu)." In Theoretical and Experimental Aspects of Valence Fluctuations and Heavy Fermions. Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-0947-5_66.
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Janaki, J., and G. V. Subba Rao. "Studies on ZrSiS and ZrMSiAs(M=Cu,Ni) Phases with the PbFCl Structure." In Theoretical and Experimental Aspects of Valence Fluctuations and Heavy Fermions. Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-0947-5_124.
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Zou, Zheng Guang, Yi Wu, Fei Long, Wen Wu Xu, and Dong Ye Yao. "Effects of Mo(Ni) on Valence Electron Structures of TiC/Fe Cermets." In High-Performance Ceramics V. Trans Tech Publications Ltd., 2008. http://dx.doi.org/10.4028/0-87849-473-1.1119.
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Canich, J. M., and G. L. Gard. "Synthesis of High-Valent Fluorides, Oxide Fluorides and Fluorocomplexes of Fe, Co, NI." In Inorganic Reactions and Methods. John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145180.ch172.
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Kakizaki, A., K. Ono, and Y. Saitoh. "Spin-resolved Photoemission of Valence Band and Core Level Satellites of Ni." In Proceedings of the 11th International Conference on Vacuum Ultraviolet Radiation Physics. Elsevier, 1996. http://dx.doi.org/10.1016/b978-0-444-82245-1.50079-0.
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Lal, Pyare. "An Advanced Study on Temperature Affected Electro-optic Properties of In0.73Al0.07Ga0.20As/InP in Fiber-optic Communications under Bi-modes." In Intelligent Technologies for Scientific Research and Engineering. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815079395123010007.
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This fundamental research work has aimed to investigate an advanced study on temperature-affected electro-optic characteristics of In0.73Al0.07Ga0.20As/. In Pheterointerface nanostructure in fiber-optic communication systems underpolarizing transverse bi-modes. In this advanced computing, under the various effects of temperatures, the various energies values of C-V(Conduction-Valence),quasi-Fermi sublevels with the various values of carriers of charge (in cm-3) have been illustrated curvedly. Next, the temperature-dependent computing performances of NI(Near Infrared) material gains within the photon's wavelength and concentration values of carriers under polarizing transverse bi-modes have been investigated graphically in this chapter. In addition, temperature-influenced performances of ROFs (Relaxation Oscillation Frequencies) in Hz with various current values in Acm-2 have been computed graphically. Further, the graphical performances of peak RIC (Refractive Index Change) with various temperature values for both polarize TE & TM-modes. In the computational investigation through the results, the crest values of NI-material gain amplification have been found corresponding to two peaks at the photon's wavelengths ~ 1331 nm and 1551 nm for various effects of temperatures under TE-mode. Although, under TM-mode, the crest value of NI-material gain amplification has been found,corresponding to a single peak at the wavelength ~ 1331 nm for various effects of temperatures. The NI-emitting light of peak intensity emitted by the proposed nanoscale-heterogeneous junction-based nanostructure of wavelengths ~ 1331 nm and 1551 nm has been largely utilized in the FCs (Fiber-optic Cables) based NItelecommunications and several NI-therapies by TIM (Total Internal-reflection Method) with minimal attenuation loss of appropriate NI-signals (in dB km-1) on account of no dispersions, no scattering and no absorptions in the emerging and advanced nanotechnology, medical nanosciences and nanoscale-biotechnology.
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Moná Ramírez, Daniela. "Gloria Valencia de Castaño tradición y trasgresión en voz de la primera dama de la radio colombiana, 1951-1966." In Ni calladas ni sumisas. Trasgresión femenina en Colombia, siglos XVII – XX. Editorial Uniagustiniana, 2021. http://dx.doi.org/10.28970/9789585498662.04.
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Este estudio se ocupa de la participación de Gloria Valencia de Castaño en la radiodifusión colombiana entre el comienzo de la década de 1950 y mediados de la década de 1960. Valencia de Castaño es conocida como “la primera dama de la televisión colombiana”. Hoy en día siguen siendo muchas las personas que la recuerdan por su aparición en programas como “Carta de Colombia” (RTI Televisión, 1970-1979) y “Naturalia” (RTI, 1974-1993). Aun cuando fue su participación en la televisión lo que la posicionó en la memoria de los colombianos, este capítulo postula que su triunfo en la pantalla chica es “la puntada final” de una carrera adelantada y consolidada en la radio. Analizamos la voz femenina en la radio en general y, específicamente, la importancia que tuvo el quehacer radiofónico de Valencia de Castaño para abrirle espacios a la participación de mujeres en contextos tradicionalmente masculinizados. Nuestras principales fuentes documentales son registros de los programas radiales “Cosas de mujeres” (1951-1955) y “El espacio de Gloria” (1965-1966). Este material fue producido y difundido en su momento por la HJCK: el mundo en Bogotá, una de las primeras emisoras culturales independientes en el país y donde Valencia era la principal voz femenina.
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Heberer, Neil, Chi-Herng Hu, and Liviu M. Mirica. "High-Valent Ni Coordination Compounds." In Comprehensive Coordination Chemistry III. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-08-102688-5.00104-5.
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Tiwari, Ashish, R. H. Talwekar, and Ravi Kumar. "Theoretical Analysis and Design of Microphotodiodes Material for Artificial Retina Implant." In Nanoelectronics Devices: Design, Materials, and Applications Part II. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815179361123010005.
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As a typical member of two-dimensional TMDs, molybdenum disulfide (MoS2 ) has excellent carrier mobility, a sizable surface area, thermal stability, and optoelectronic features. Due to its tunable bandgap, strong valence–conduction band bonding, and use in optoelectronic sensors, photodiodes, and phototransistors, MoS2 has emerged as a possible substitute for graphene. For better optoelectronic properties, MoS2 -based monolayers and crystals have recently been investigated using a variety of heterostructures, including MoS2 /graphene, MoS2 /CNT and MoS2 /WS2 . It was also mentioned that MoS2 phototransistors and sensors had poor light sensitivity because of their insufficient ability to absorb light. The right choice of material is essential for biomedical implants, including retinal implants, neuroprosthetic implants, and others where photodiodes are used to generate electrical currents in reaction to incident light Au-based nanoparticles and nanoarrays have been added to the MoS2 monolayer to address the low absorption problem. For increased quantum efficiency, MoS2 monolayers based on solar cells and light-emitting diodes have also recently been created. In some of the other research, other transition metal (TM) atoms, such as Au, Ag, Cu, Nb, Tc, Ta, Re, Co, Ni, Fe, and Mn, were substituted into the monolayer of MoS2 , enhancing the material's electrical, magnetic, electrocatalytic, and gas adsorption capabilities. The combined electrical and optical properties of TM-doped and alkaline metal (AM) doped MoS2 bulk layers haven't received much attention, though. In this study, the effects of doping MoS2 bulk layers with TM atoms (Au, Ag, and Cu) and AM atoms (Na, Li) were investigated using first-principles DFT calculations. We investigated the density of states (DOS), band structures, structural features, optical conductivity, absorption, and reflectivity of five different doped MoS2 bulk layers. The results show that AM atom doping narrows the MoS2 bulk layer's bandgap more than TM doping. Bandgap values ranged from 1.42 eV for the undoped MoS2 layer to 0.609 eV for the Li-MoS2 layer. Additionally, it was discovered that bulk layers of MoS2 doped with AM had higher optical conductivity and absorption qualities and lower reflectivity. In applications of MoS2 - based photodiode/phototransistor sensors, doping of AM atoms may show to be a successful substitute for conventionally used TM (Au) doped arrays.
Conference papers on the topic "Valence du Ni"
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Kinyanjui, Michael. "Nature and origin of the spectral features observed in the valence energy loss of Li-Mn-Ni-O spinel oxides spectra with respect to Mn valency changes." In European Microscopy Congress 2020. Royal Microscopical Society, 2021. http://dx.doi.org/10.22443/rms.emc2020.1200.
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SEIDOU, Abdul Herrim. "Differential thermal analysis to assist the design of corrosion-resistant high entropy alloys for laser powder bed fusion." In Material Forming. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903131-40.
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Abstract. In this study, Al, Cr, Fe, Mn, and Ni are selected and pure elemental powders were used to prepare several medium entropy alloys (MEAs) and high entropy alloys (HEAs). Differential Thermal Analysis (DTA) is used as a tool for pre-screening of the compositions suitable to design corrosion-resistant alloys for Laser Powder Bed Fusion (LPBF). The advantage of DTA lies in the precise temperature control and in the small quantity of powder necessary to perform the test in near-equilibrium conditions. The powder mixtures were heated up to 1550°C, fully melted, and then cooled down to room temperature at 5°C/min. The results of DTA are used as reference to understand the complex microstructures obtained using LPBF. Microstructure analysis of DTA samples by combining Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) helped to confirm the phase prediction theories. Most of the samples showed a heterogeneous structure with Ni-Al rich B2 phase, Fe-Cr rich BCC and FCC phases. The spinodal decomposition of the BCC phase was also observed in the equimolar AlCrFeMnNi sample. The Valence Electron Concentration (VEC) theory was verified and the partitioning of the elements between the phases was investigated.
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Punanova, Svetlana. "ORE CONCENTRATIONS OF METALS IN NAPHTHIDES OF HYPERGENESIS ZONE: ASSESSMENT AND ENVIRONMENTAL ASPECT." In GEOLINKS International Conference. SAIMA Consult Ltd, 2020. http://dx.doi.org/10.32008/geolinks2020/b1/v2/17.
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The study examines the formation of secondary-altered crude oils associated with the processes of modern or ancient hypergenesis. As a result of geological processes during intense upward movement of the earth's crust, oil undergoes physical weathering, inorganic oxidation, washing out with water, biodegradation and sulfurization, and turn into heavy oils and hard bitumen. In zones of hypergenesis, the loss of light fractions occurs and the absolute concentration of trace elements (TE) associated with resinous-asphaltene components, such as V, Ni, Co, Mo, Cr, Cu, etc. sharply increases. In addition, oils absorb elements of variable valence (V, Fe, U) from low-salinity stratal waters. As a result of experimental studies on the interaction of oils with low mineralization waters, which are characteristic of hypergenesis zones, leaching of some elements (e.g., Zn) from oils and absorption of others from contacting waters (for example, concentrations of newly-formed organometallic compounds V and Fe increased by 1.3-12 times) were found. The author utilized the method of neutron-activation analysis to study the content of TE in oils and natural bitumens of the Volga-Ural, Timan-Pechora, Kazakhstan, Tajikistan, and etc. Ore-level concentration values were found, for example: 180-1162 ppm for V and up to 100 ppm for Ni in the oils of the Melekess depression in Tatarstan, and 940 ppm for V and 130 ppm for Ni in the oils of Kazakhstan deposits. Classification of oils by the content of “biogenic” elements V, Ni, Fe and by physical and chemical properties revealed significant differences of hypergene-altered oils in the general cycle of genesis of naphthides. Deposits of secondarily-altered oils are found in a wide stratigraphic range in oil and gas basins of various geostructural types in traps of the combined morphology – lithologically and tectonically shielded. During the development of oil deposits that contain high concentrations of TE, it is necessary to take into account ecological aspects. The environmental aspect is due to the fact that many metals contained in oils – V, Ni, Cd, As, Hg, U, etc. belong to highly toxic compound chemicals.
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Codreanu, Liviu. "Chromium bioaccumulation potential of edaphic cyanobacterium nostoc linckia grown on multimetallic systems." In 5th International Scientific Conference on Microbial Biotechnology. Institute of Microbiology and Biotechnology, Republic of Moldova, 2022. http://dx.doi.org/10.52757/imb22.16.
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Over the past few decades, chromium contamination of both terrestrial and aquatic ecosystems has increased as a result of various anthropogenic activities. In this regard, various useful and practical remediation technologies have been emerging to control chromium content in water, soil and other resources. Chromium remediation through microorganisms may be the best technology currently available for cleaning up Cr contaminated sites. These technologies using biological agents are cheaper, safer and ecofriendly than chemical treatment methods. Cr exists in several oxidation states, but the most stable and common forms are Cr(0), Cr(III) and Cr(VI) species. Chromium toxicity depends on its valence state. Hexavalent chromium is a highly mobile and toxic contaminant. Cr(III) being less mobile is much less toxic than Cr(VI). The purpose of this study was to assess the potential of cyanobacterium Nostoc linckia to accumulate hexavalent chromium during three successive cultivation cycles on multimetallic systems. Cyanobacterium Nostoc linckia (Roth) Born et Flah CNM-CB-03 was grown in a mineral medium and metal ions in different combinations. Cultivation was carried out in Erlenmayer flasks of 1000 mL with a working volume of 700 mL. The following parameters were used: pH of the medium 6.8-7.2, temperature 25-27oC, light intensity of 37-55 μmol photons m-2 s-1, continuous illumination, slow periodic shaking. The amount of inoculum was 0.4 g/L. Each cultivation cycle lasted 12 days. Multimetallic systems Cr/Fe, Cr/Fe/Ni, Cr/Fe/Ni/Zn and Cr/Fe/Ni/Zn/Cu were added to culture medium on the exponential phase of nostoc growth. In this study, the bioaccumulation of Cr(VI) from multimetallic systems was performed - a situation that is closer to real conditions, since in most cases the contamination of certain areas occurs due to the presence of several pollutants. Among the four studied systems, in Cr/Fe, Cr/Fe/Ni, and Cr/Fe/Ni/Zn/Cu, the rate of chromium uptake by nostoc was very similar and varied with the cultivation cycle. Thus, in these three systems, chromium uptake in the first cultivation cycle was 35.8-40.2% of the initial level of metal; in the second cycle - 27.2-32.7%, and in the third cycle - 19.7-27.1%. In Cr/Fe/Ni/Zn system, the bioaccumulation capacity of nostoc biomass was significantly higher and amounted to 63.1%, 56.0% and 34.8% of Cr(VI), which corresponds to three cultivation cycles. Moreover, Fe, Ni, Zn and Cu were also taken up during the cultivation of nostoc biomass from one cycle to another. For instance, iron uptake in the first cycle was 59-78% and it was accumulated almost completely in the next two cycles. Nickel uptake in the first cycle was 43.2-62.6%, in the next two - 49.7-83.1%. The percentage of zinc recovery by nostoc biomass was at the same level in all three cycles and amounted to 37.1-39.8% of its initial content in the Cr/Fe/Ni/Zn system. In the Cr/Fe/Zn/Ni/Cu system, zinc uptake increased from 25.8% in the first cycle to 54.5% in the third one. Copper uptake was 46.5-57.8%, and its maximum amount was accumulated in the second cycle of nostoc cultivation. Thus, the culture of Nostoc linckia demonstrated resistance to multimetallic systems and a high potential for bioaccumulation of Cr(VI) and other metals present. The capacity of cyanobacterium Nostoc linckia to bioaccumulate Cr(VI) from the contaminated medium remained high over three generations, while the uptake of Fe, Ni, Cu and Zn in the biomass increased from generation to generation. In conclusion, edaphic cyanobacterium Nostoc linkia is a good accumulator of chromium, but also of other metals in multimetallic systems. Due to its biological nature, Nostoc linckia is a suitable matrix for remediation processes that offers a vast competition ground for metal cations. Therefore, the use of microorganisms for heavy metal removal is a sustainable remediation approach that must be adopted in order to balance the environment and nature.
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Hameed, Areeba, Khulood Logade, Naba Ali, et al. "Highly active Bifunctional Lamo3 (M=Cr, Mn, Fe, Co, Ni) Perovskites for Oxygen Reduction and Oxygen Evolution Reaction in Alkaline Media." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0106.
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Lanthanum based electrocatalytically active perovskites, LaMO3 (M=Cr, Mn, Fe, Co, Ni), were synthesized using a single step solution combustion synthesis technique. The perovskites showed exceptional performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline medium. Based on the experimental results and literature survey, it is suggested that the exceptional activity of Mn and Co based lanthanum perovskite catalyst could be due to the optimum stabilization of reaction intermediates involved in the rate-determining step (RDS) of ORR/OER. According to crystal field theory (CFT), the d-orbital of transition metals are affected by the octahedral arrangement of six negative charges around it. The d orbital degenerates by splitting into two high energy (eg) and three lower energy orbitals (t2g) while maintaining the same average energy level. The rate-determining step in the ORR/OER reaction that based on the eg orbital filling of B site transition metal cations If the d-electrons are less, the valence state goes up and lowering the eg orbital filling that results in strong adsorption of oxygenated species on the B site (strong B-OH bond). This strong bonding limits the overall reaction rate by the slow desorption of OH and its derivatives during ORR/OER. Similarly, too high eg filling causes weak adsorption of oxygenated species that limits the reaction through the slow adsorption of reactants. Therefore, to enhance the activity of ORR/OER reaction it is required to balance the adsorption and desorption of the reactants and the intermediate respectively. The better way is to optimize the eg orbital filling to be nearly 1 (eg = 1).Based on the experimental results and literature survey, it is suggested that the exceptional activity of Mn and Co based lanthanum perovskite catalyst could be due to the optimum stabilization of reaction intermediates involved in the rate-determining step (RDS) of ORR and OER.
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Manabe, Toshio, Masahiro Yamashita, Takuya Kawashima, et al. "Competition between electron correlation of NiIIIstates and electron-phonon interaction of PdII-PdIVmixed-valence states in quasi-one-dimensional halogen-bridged mixed-metal complexes, Ni 1- x Pd X (chxn) 2 Br 3." In Optical Science, Engineering and Instrumentation '97, edited by Z. Valy Vardeny and Lewis J. Rothberg. SPIE, 1997. http://dx.doi.org/10.1117/12.279273.
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Chen, H. C., Q. Z. Jiang, X. L. Lu, and L. Chen. "Doping Modification Of Photorefractive Crystal Potassium Sodium Strontium Barium Niobate." In The European Conference on Lasers and Electro-Optics. Optica Publishing Group, 1996. http://dx.doi.org/10.1364/cleo_europe.1996.ctuk75.
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During recent year, the photorefractive materials are attractive in many applications such as optical image processing and optical computing because they have more lower threshold power and easily realize phase conjugation Potassium sodium strontium barium niobate crystal is one of the best candidates. It has open structure and large structure tolerance for dopants with different valence There are two different ways to improve the photorefractive properties of the materials. 1) by adjusting the composition of materials and 2) doping cation ions. This paper is to describe the doping effects on the ferroelectric and photorefractive properties. The composition of potassium sodium strontium barium niobate was chosen as 92% of A-sites occupied by K, Na, Sr and Ba ions. The dopants such as Ce, Pr, Fe, Co, Ni, Cu, Ti and Mn with 0.01-0.1wt% were adopted for modifying the properties. Potassium sodium strontium barium niobate crystals were grown from platinum crucible by Czochralski method with induction heating in air atmosphere. The growth conditions are pulling direction: [001], the rate of pulling/rotation: 0.2-0.4. The size of as-grown crystal is up to ϕ 35 × 35 mm From the shape of hysteresis loops, the doping effect on ferroelectric properties of potassium sodium strontium barium niobate crystals were revealed to have three categories: expansive, stable and shrink for Fe, Cu and others, respectively After the temperature recycle from 100 to 500K, the d33 value for Cu-doped crystal does not change, which suggest that the Cu ion is a good polarization stabilizer. The self-pumped phase conjugation refractivities for Ce, Co and Cu-doped crystals are much higher than the others. They are 70% at 514.5nm for Cu-doped, 73% at 514.5nm for Co-doped and 84% at 632.8nm for Ce-doped respectively.
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Kasatenkova, Maria, Maria Kasatenkova, Nicolay Kasimov, Nicolay Kasimov, Mihail Lychagin, and Mihail Lychagin. "CHANGES IN BACKGROUND CONCENTRATIONS OF METALS IN THE SEDIMENTS OF MARSH-LAGOON LANDSCAPES OF THE WESTERN CASPIAN." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b937de4b5c6.59040974.
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The last 1978-1995 transgression of the Caspian Sea caused the development of marsh-lagoon system along the Western Caspian seashore. Due to salt marshes are very vulnerable to sea-level fluctuations, complex and dynamic system, they may be considered as a regional model of rapid environmental transformation. Changing conditions of migration in the soils of marsh-lagoon landscapes during the sea-level rise influenced on the migration of elements of variable valency, primarily Fe and Mn, but also Zn, Cu, Pb, Ni, Co, leading to their mobilization in slightly alkaline and neutral reducing conditions and subsequent deposition on the geochemical barriers. That led to the emergence of landscape-geochemical anomalies of Fe and heavy metals in the soils of salt marshes with a characteristic time of formation of any persistent anomalies during 5-10 years.
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Kasatenkova, Maria, Maria Kasatenkova, Nicolay Kasimov, Nicolay Kasimov, Mihail Lychagin, and Mihail Lychagin. "CHANGES IN BACKGROUND CONCENTRATIONS OF METALS IN THE SEDIMENTS OF MARSH-LAGOON LANDSCAPES OF THE WESTERN CASPIAN." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b4315901d72.
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The last 1978-1995 transgression of the Caspian Sea caused the development of marsh-lagoon system along the Western Caspian seashore. Due to salt marshes are very vulnerable to sea-level fluctuations, complex and dynamic system, they may be considered as a regional model of rapid environmental transformation. Changing conditions of migration in the soils of marsh-lagoon landscapes during the sea-level rise influenced on the migration of elements of variable valency, primarily Fe and Mn, but also Zn, Cu, Pb, Ni, Co, leading to their mobilization in slightly alkaline and neutral reducing conditions and subsequent deposition on the geochemical barriers. That led to the emergence of landscape-geochemical anomalies of Fe and heavy metals in the soils of salt marshes with a characteristic time of formation of any persistent anomalies during 5-10 years.
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Muñoz Suárez, Daniel, María Vanessa Galindo Ramírez, and Yair Martínez Martínez. "La evaluación formativa a través de los medios formales, semiformales y no formales, el caso de expresiones y polinomios algebraicos." In IN-RED 2019: V Congreso de Innovación Educativa y Docencia en Red. Editorial Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/inred2019.2019.10488.
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El presente trabajo describe la relación entre la satisfacción percibida por los estudiantes con los medios de evaluación, en función de los logros y el rendimiento académico al adquirir competencias y formación en expresiones y polinomios algebraicos. Es por lo anterior, que la evaluaciòn se convierte en el eje fundamental de la estrategìa metodològica para la enseñanza-aprendizaje, requiriendo señalar que ambas no tienen objetivos separados ni ausentes una de la otra; es decir, que no se entenderán como la consecución de un procedimiento que está constituido por la planeación, la ejecución y finalmente por su posterior “evaluación”; sino en su lugar se considera un proceso de evaluación permanente donde ésta se transversaliza con la enseñanza y el aprendizaje, modificando la didáctica, la pedagogía y puntualizando la concepción misma de evaluación. Anotando entonces, que la evaluación cuando se refiere a la educación, no se debe de mirar únicamente con calificativos cuantitativos o cualitativos, sino que debe partir de un carácter formativo y reflexivo, el cual permite reconocer el conocimiento adquirido. En concreto, la evaluación puede valerse de instrumentos que arrojen resultados numéricos, pero teniendo en cuenta los medios y técnicas propios de ella, para propiciar el alcance de un aprendizaje significativo.