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Relevant bibliographies by topics / 2- dimensional electron system (2 DES)

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Academic literature on the topic '2- dimensional electron system (2 DES)'

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Published: 6 September 2023

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Journal articles on the topic "2- dimensional electron system (2 DES)"

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Zaluzec, N. J., and M. G. Strauss. "EELS parallel detection using 2-dimensional CCD array." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 662–63. http://dx.doi.org/10.1017/s0424820100105370.

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Conventional parallel detectors for Electron Energy Loss Spectroscopy (EELS) have been mainly based upon systems using linear photodiode arrays in a conjugate image plane of an electron spectrometer. We have developed a unique two dimensional charge coupled device (CCD) camera system which can be used as a detector for EEL spectroscopy and imaging, utilizing high sensitivity, high resolution CCD's, which are typically used in medial or astronomic imaging.The present detector system is based upon a Tektronics TK512M 512 x 512 pixel CCD array, (figure 1) which is optically coupled to a YAG:Ce single crystal scintillator. This CCD imaging system views an electron energy loss spectrum which is magnified by a quadrupole doublet lens attached to a Gatan 607 electron spectrometer on a Philips EM420 TEM as is illustrated in figure 2. The CCD controller, detector head electronics and electron optics were developed at Argonne specifically for high speed data acquisition and allow the recording of complete spectra in as short a time as 10 μsec or approximately 103 times faster than the typical 1024 pixel photodiode arrays’ thus allowing the potential for time resolved spectroscopy.

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KVON, Z. D., E. B. OLSHANETSKY, D. A. KOZLOV, N. N. MIKHAILOV, and S. A. DVORETSKII. "A NEW TWO-DIMENSIONAL ELECTRON-HOLE SYSTEM." International Journal of Modern Physics B 23, no. 12n13 (May 20, 2009): 2888–92. http://dx.doi.org/10.1142/s0217979209062499.

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A two-dimensional electron-hole system consisting of light high-mobility electrons with a density of Ns = (4 - 7) × 1010 cm -2 and heavier lower-mobility holes with a density Ps = (0.7 - 1.6) × 1011 cm -2 has been discovered in a quantum well based on mercury telluride with the (013) surface orientation. The system exhibits a number of specific magnetotransport properties in both the classical magnetotransport (positive magnetoresistance and sign-variable Hall effect) and the quantum Hall effect regime. These properties are associated with the coexistence of two-dimensional electrons and holes and actually manifest the first realization of a two-dimensional semimetal.

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von Harrach, H. S., and J. A. Colling. "A 2-dimensional detection system for Electron Energy Loss Spectroscopy." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 408–9. http://dx.doi.org/10.1017/s0424820100154019.

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A UHV-compatible parallel and serial detection system for electron energy-loss spectroscopy (EELS) has been developed for the VG HB501 field-emission scanning transmission electron microscope (STEM) using a 2-dimensional detector. As pointed out previously the charge coupled devices (CCD) available commercially are vastly superior, in terms of read-out noise, to linear photodiode arrays which are currently used for parallel EELS detection. This feature, together with the ability of operating as an imaging and storage device, makes the 2-dimensional CCD array an attractive choice for parallel EELS and low light-level imaging applications.The system reported here (Fig. 1) is an extension of the VG ELS501 sector magnetspectrometer used for serial EELS with many STEMS. It uses one quadrupole lens to magnify the energy-loss spectrum over a range of 2 to 0.1 eV per detector element. An electromagnetic deflector steers the spectrum to one of three YAG scintillators. Two of these scintillators with suitable masks are used for parallel EELS detection; the third is used for serial EELS and energy filtered STEM imaging via a lightguide and photomultiplier system by scanning the beam across a variable slit as in ELS 501 systems.

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Taboryski, R., and P. E. Lindelof. "Spin-orbit effects in a 2-dimensional electron gas system with 2 subbands occupied." Physica B: Condensed Matter 165-166 (August 1990): 859–60. http://dx.doi.org/10.1016/s0921-4526(09)80015-x.

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Huang, Geng-Ling, Rue-Ron Hsu, Chin-Rong Lee, and Hsiang-Nan Li. "Study of a 2+1 dimensional electron-monopole system via supersymmetry." Physics Letters A 191, no. 1-2 (August 1994): 7–12. http://dx.doi.org/10.1016/0375-9601(94)90552-5.

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Lissayou, J., J. C. Bissey, and Y. Servant. "Electron paramagnetic resonance of the two-dimensional system Mn(CH3COO)2·4H2O." Solid State Communications 57, no. 8 (February 1986): 717–19. http://dx.doi.org/10.1016/0038-1098(86)90359-5.

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Bissey, Jean-Claude, Jean Lissayou, and Yves Servant. "Electron Paramagnetic Resonance of the two-dimensional system Mn(HCOO)2·2H2O." Journal of Magnetism and Magnetic Materials 59, no. 1-2 (May 1986): 5–8. http://dx.doi.org/10.1016/0304-8853(86)90003-x.

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Hu, G. Y., and R. F. O'Connell. "Dielectric response of a quasi-one-dimensional electron system." Journal of Physics: Condensed Matter 2, no. 47 (November 26, 1990): 9381–97. http://dx.doi.org/10.1088/0953-8984/2/47/013.

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Zvyagin, A. A., H. Johannesson, and M. Granath. "Multichannel Kondo screening in a one-dimensional correlated electron system." Europhysics Letters (EPL) 41, no. 2 (January 15, 1998): 213–18. http://dx.doi.org/10.1209/epl/i1998-00567-2.

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Yi, Wang, Wang Kelin, and Wan Shaolong. "Soliton-Like Bipolaron in Two-Dimensional Deformable Electron-Phonon System." Communications in Theoretical Physics 29, no. 2 (March 15, 1998): 309–12. http://dx.doi.org/10.1088/0253-6102/29/2/309.

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Dissertations / Theses on the topic "2- dimensional electron system (2 DES)"

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Göres, Jörn. "Correlation effects in 2-dimensional electron systems composite fermions and electron liquid crystals /." [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11612017.

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Geisler, Martin C. "The Hofstadter butterfly and quantum interferences in modulated 2-dimensional electron systems." [S.l. : s.n.], 2005. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-26027.

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Nübler, Johannes [Verfasser], and David [Akademischer Betreuer] Wharam. "Density Dependence of the v=5/2 Fractional Quantum Hall Effect - Compressibility of a Two-dimensional Electron System under Microwave Irradiation / Johannes Nübler ; Betreuer: David Wharam." Tübingen : Universitätsbibliothek Tübingen, 2011. http://d-nb.info/1162699248/34.

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Rosner, Helge. "Electronic structure and exchange integrals of low-dimensional cuprates." [S.l. : s.n.], 1999. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9470690.

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Magyar, Peter. "Quelques aspects du transport électronique bidimensionnel : études théoriques en champ magnétique faible et fort." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10025.

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Ce travail presente deux etudes de transport des systemes d'electrons bidimensionnels dans les limites du champ magnetique faible et fort. Premierement, nous avons analyse l'utilite d'une nouvelle approche theorique, destinee a calculer la mobilite limitee par (a) des impuretes ionisees ou par (b) des dislocations. Ce traitement a pour but d'ameliorer la description de l'effet d'ecran. Notre etude a revele que la methode ne represente que des avantages tres limites dans le cas (a), tandis que dans le cas (b) les courbes calculees en fonction de la temperature et de la largeur du puits sont en accord avec les mesures. Deuxiemement, l'effet hall quantique entier a ete etudie dans un potentiel de desordre modele. Le systeme a ete couple a un bain thermique. A partir de l'etat stationnaire d'une equation de boltzmann quantique, les conductivites de hall et dissipative ont ete obtenues en fonction de la temperature pour tous les facteurs de remplissage. Nos resultats sont en accord qualitatif avec les experiences. En outre, ils montrent que, du aux phonons, les plateaux quantifies de la conductivite de hall sont sensiblement plus larges a tres basses temperatures que ceux de la conductivite dissipative.

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Carter, Paul James Anthony. "Acoustic phonon scattering by a 2 dimensional electron gas." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329844.

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Ford, E. M. "Single electron conduction in 2-dimensional arrays of gold nanodots." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599113.

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This dissertation considers single electron conduction through arrays of nanometer-size metallic islands fabricated by Focused Ion Beam (FIB) lithography. Control of the array geometry and the corresponding electrical characteristics were achieved by variation of the FIB deposition conditions. Scanning electron microscopy was used to examine FIB depositions on Si/SiO₂ substrates. For more accurate examination transmission electron microscopy was used to image arrays deposited on carbon membranes. Image analysis software revealed a general increase in island diameter and reduction of island density with increasing FIB dose. The average island size was found to decrease with increasing FIB landing energy, although the uniformity of the deposition was reduced. The process of island formation is discussed in relation to the trends observed. Devices were fabricated with a planar structure, consisting of closely-spaced (~10 nm) source and drain electrodes situated within a large area array of islands. The devices were created on silicon substrates with a top layer of thermally grown silicon dioxide. A chromium oxide film was deposited by R.F. sputtering and the electrodes were then defined by high-resolution electron beam lithography. Electrical measurements were carried out at temperatures between 4.2K and 300K. Characteristics typical of single-electron conduction were observed, including the Coulomb gap and staircase, and the reduction of the Coulomb gap width with increasing temperature. The width of the low-temperature Coulomb gap was found to diminish with increasing dose, while devices fabricated with higher landing energies have lower operating temperatures. A novel device structure was also fabricated, where a small number of gold islands were isolated on the surface of a silicon nanowire. Silicon wires of length ~1μm and width >10nm were fabricated reproducibly using a sacrificial metallic etch mask. The electrical characteristics exhibited Coulomb gaps consistent with single electron transport.

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Lee, Sungkoo. "A constraint-based 2-dimensional object display system." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055342896.

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McEnaney, Kevin Bernard. "Magneto-absorption of surface acoustic waves by a 2-dimensional electron gas." Thesis, University of Nottingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293651.

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Martin, Theodore Peyton. "Low-dimensional electron transport in mesoscopic semiconductor devices /." view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?did=1280149921&sid=2&Fmt=2&clientId=11238&RQT=309&VName=PQD.

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Thesis (Ph. D.)--University of Oregon, 2006.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 187-196). Also available for download via the World Wide Web; free to University of Oregon users.

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Books on the topic "2- dimensional electron system (2 DES)"

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Andrei, Eva Y., ed. Two-Dimensional Electron Systems. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-015-1286-2.

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Göres, Jörn. Correlation effects in 2-dimensional electron systems: Composite fermions and electron liquid crystals. Stuttgart: Max-Planck-Institut für Festkörperforschung, 2004.

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Aoki, H., M. Tsukada, M. Schlüter, and F. Lévy, eds. New Horizons in Low-Dimensional Electron Systems. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-3190-2.

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Okiji, Ayao, and Norio Kawakami, eds. Correlation Effects in Low-Dimensional Electron Systems. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-85129-2.

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Alexandrov, Georgii A. Carbon sink archives: An integrated system for storing, retrieving and analyzing 2-dimensional data related to the problem of terrestrial carbon sink. Tsukuba, Japan: Center for Global Environmental Research, National Institute for Environmental Studies, 2009.

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Staples, I. Application of the coupled cluster method to the two dimensional triangular lattice frustrated spin-1/2 system with an antiferromagnetic Heisenberg Hamiltonian. Manchester: UMIST, 1994.

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service), SpringerLink (Online, ed. Cooperative Design, Visualization, and Engineering: 9th International Conference, CDVE 2012, Osaka, Japan, September 2-5, 2012. Proceedings. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012.

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Araújo, Ana Cláudia Vaz de. Síntese de nanopartículas de óxido de ferro e nanocompósitos com polianilina. Brazil Publishing, 2021. http://dx.doi.org/10.31012/978-65-5861-120-2.

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In this work magnetic Fe3O4 nanoparticles were synthesized through the precipitation method from an aqueous ferrous sulfate solution under ultrasound. A 23 factorial design in duplicate was carried out to determine the best synthesis conditions and to obtain the smallest crystallite sizes. Selected conditions were ultrasound frequency of 593 kHz for 40 min in 1.0 mol L-1 NaOH medium. Average crystallite sizes were of the order of 25 nm. The phase obtained was identified by X-ray diffractometry (XRD) as magnetite. Scanning electron microscopy (SEM) showed polydisperse particles with dimensions around 57 nm, while transmission electron microscopy (TEM) revealed average particle diameters around 29 nm, in the same order of magnitude of the crystallite size determined with Scherrer’s equation. These magnetic nanoparticles were used to obtain nanocomposites with polyaniline (PAni). The material was prepared under exposure to ultraviolet light (UV) or under heating, from dispersions of the nanoparticles in an acidic solution of aniline. Unlike other synthetic routes reported elsewhere, this new route does not utilize any additional oxidizing agent. XRD analysis showed the appearance of a second crystalline phase in all the PAni-Fe3O4 composites, which was indexed as goethite. Furthermore, the crystallite size decreases nearly 50 % with the increase in the synthesis time. This size decrease suggests that the nanoparticles are consumed during the synthesis. Thermogravimetric analysis showed that the amount of polyaniline increases with synthesis time. The nanocomposite electric conductivity was around 10-5 S cm-1, nearly one order of magnitude higher than for pure magnetite. Conductivity varied with the amount of PAni in the system, suggesting that the electric properties of the nanocomposites can be tuned according to their composition. Under an external magnetic field the nanocomposites showed hysteresis behavior at room temperature, characteristic of ferromagnetic materials. Saturation magnetization (MS) for pure magnetite was ~ 74 emu g-1. For the PAni-Fe3O4 nanocomposites, MS ranged from ~ 2 to 70 emu g-1, depending on the synthesis conditions. This suggests that composition can also be used to control the magnetic properties of the material.

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Horing, Norman J. Morgenstern. Interacting Electron–Hole–Phonon System. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198791942.003.0011.

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Chapter 11 employs variational differential techniques and the Schwinger Action Principle to derive coupled-field Green’s function equations for a multi-component system, modeled as an interacting electron-hole-phonon system. The coupled Fermion Green’s function equations involve five interactions (electron-electron, hole-hole, electron-hole, electron-phonon, and hole-phonon). Starting with quantum Hamilton equations of motion for the various electron/hole creation/annihilation operators and their nonequilibrium average/expectation values, variational differentiation with respect to particle sources leads to a chain of coupled Green’s function equations involving differing species of Green’s functions. For example, the 1-electron Green’s function equation is coupled to the 2-electron Green’s function (as earlier), also to the 1-electron/1-hole Green’s function, and to the Green’s function for 1-electron propagation influenced by a nontrivial phonon field. Similar remarks apply to the 1-hole Green’s function equation, and all others. Higher order Green’s function equations are derived by further variational differentiation with respect to sources, yielding additional couplings. Chapter 11 also introduces the 1-phonon Green’s function, emphasizing the role of electron coupling in phonon propagation, leading to dynamic, nonlocal electron screening of the phonon spectrum and hybridization of the ion and electron plasmons, a Bohm-Staver phonon mode, and the Kohn anomaly. Furthermore, the single-electron Green’s function with only phonon coupling can be rewritten, as usual, coupled to the 2-electron Green’s function with an effective time-dependent electron-electron interaction potential mediated by the 1-phonon Green’s function, leading to the polaron as an electron propagating jointly with its induced lattice polarization. An alternative formulation of the coupled Green’s function equations for the electron-hole-phonon model is applied in the development of a generalized shielded potential approximation, analysing its inverse dielectric screening response function and associated hybridized collective modes. A brief discussion of the (theoretical) origin of the exciton-plasmon interaction follows.

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Zarembo, Jaroslavs. Research and Development of the Synchronous Reluctance Motor Traction Drive. RTU Press, 2022. http://dx.doi.org/10.7250/9789934227844.

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The aim of the Doctoral Thesis is the design, development and testing of an electric drive based on SynRM and a two-level frequency inverter for traction application. Within the research an electric motor in the overall dimensions of an existing serial induction motor for the trolleybus was developed, manufactured, and investigated. The result of the work was the development and testing of a new model of traction SynRM with control system for trolleybus drive. The Doctoral Thesis has been written in English. It consists of an Introduction, 5 chapters, Conclusions, 58 figures, 12 tables, and 2 appendices; the total number of pages is 80, including appendices. The Bibliography contains 40 titles.

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Book chapters on the topic "2- dimensional electron system (2 DES)"

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Platzman, Philip M. "Interactions in 2–D Electron Systems." In The Physics of the Two-Dimensional Electron Gas, 97–130. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-1907-8_4.

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Shastry, B. S. "The 1/r 2 Integrable System: The Universal Hamiltonian for Quantum Chaos." In Correlation Effects in Low-Dimensional Electron Systems, 21–35. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-85129-2_2.

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Nikolayev, V. S. "About the Influence of Uniaxial Pressure on the Twin Structure in the 1-2-3 System." In Electron-Electron Correlation Effects in Low-Dimensional Conductors and Superconductors, 54–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-76753-1_7.

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Vacek, K., A. Okiji, and N. Kawakami. "Confined System with 1/r 2 Exchange Interaction and Its Application to Resonances in Narrow Channels." In Correlation Effects in Low-Dimensional Electron Systems, 49–54. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-85129-2_5.

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Sambongi, Takashi, and Kazushige Nomura. "Dynamics of Spin-Density Wave in Organic Conductors (TMTSF)2 X." In New Horizons in Low-Dimensional Electron Systems, 401–14. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-3190-2_26.

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Ghosh, Mili, Debarka Mukhopadhyay, and Paramartha Dutta. "2-Dimensional 2-Dot 1-Electron Quantum Cellular Automata-Based Dynamic Memory Design." In Advances in Intelligent Systems and Computing, 357–65. New Delhi: Springer India, 2015. http://dx.doi.org/10.1007/978-81-322-2695-6_30.

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Nicholas, R. J., G. M. Summers, M. Watts, R. J. Warburton, J. G. Michels, R. A. Lewis, J. J. Harris, and C. T. Foxon. "Cyclotron Resonance of Mixed Phases of a 2-D System in the Ultra-Quantum Limit." In Low-Dimensional Electronic Systems, 232–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-84857-5_23.

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Shashkin, A., and S. Kravchenko. "Chapter 2. Metal-Insulator Transition in a Strongly Correlated Two-Dimensional Electron System." In Strongly Correlated Electrons in Two Dimensions, 47–64. Penthouse Level, Suntec Tower 3 8 Temasek Boulevard Singapore 038988: Pan Stanford Publishing Pte. Ltd., 2016. http://dx.doi.org/10.1201/9781315364575-3.

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Gornik, Erich. "Density of States of 2 Dimensional Systems in High Magnetic Fields." In The Physics of the Two-Dimensional Electron Gas, 365–92. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-1907-8_11.

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Datta, Kakali, Debarka Mukhopadhyay, and Paramartha Dutta. "Design of Ripple Carry Adder Using 2-Dimensional 2-Dot 1-Electron Quantum-Dot Cellular Automata." In Advances in Intelligent Systems and Computing, 263–70. New Delhi: Springer India, 2016. http://dx.doi.org/10.1007/978-81-322-2755-7_27.

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Conference papers on the topic "2- dimensional electron system (2 DES)"

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Kono, Yohei, Toshiro Sakakibara, Christopher Aoyama, Mark M. Turnbull, Christopher Landee, and Yasumasa Takano. "Magnetization Study of the Quantum Critical Behavior of the One Dimensional Spin-1/2 Heisenberg Antiferromagnet CuPzN." In Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013). Journal of the Physical Society of Japan, 2014. http://dx.doi.org/10.7566/jpscp.3.012015.

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Niida, Y., K. Takashina, A. Fujiwara, T. Fujisawa, and Y. Hirayama. "Spin resolved spectroscopy of upper subbands in two-dimensional electron systems by direct transport measurements." In 2007 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 2007. http://dx.doi.org/10.7567/ssdm.2007.c-2-4.

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Williamson, S., and G. Mourou. "Picosecond Electro-Electron Optic Oscilloscope." In Picosecond Electronics and Optoelectronics. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/peo.1985.pdp2.

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The technique of picosecond electro-optic sampling for time-resolving ultrafast electrical transients is presently the only means by which an electrical waveform can be measured with single picosecond resolution. In addition, the electro-optic sampling oscilloscope is capable of millivolt sensitivity and can be used in a contactless configuration, a feature that will enable the rapid characterization of packaged electronic circuits or 2-dimensionai mapping of electric fields. The major drawback of the electro-optic sampling oscilloscope is that it requires a short pulse laser system. The complexity of such a laser system results in a sampling oscilloscope that is delicate, maintenance intensive, and expensive, precluding its development in all but a few large laboratories.

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Blau, W., H. Byrne, and P. Horan. "Resonant Third-Order Nonlinearity of Quasi One- and Zero-Dimensional Electron Systems." In Nonlinear Optical Properties of Materials. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/nlopm.1988.tud6.

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The invention of semiconductor multi-quantum wells and the following discovery of large optical nonlinearities in them [1] have started a substantial research effort into the properties of such two-dimensional quantum confined systems. Furthermore the question of further reducing the electron dimensionality and the associated scaling laws [2] has arisen. By reducing the electron dimensionalities by confining them physically in two and three dimensions beyond their de-Broglie wavelength, the situation of the idealized "particle-in-the-box" is realized. Associated with this behavior is an increase in the exciton binding energy (observable at room temperature) and in oscillator strength, and hence also an increase of the optical nonlinearity arising from the saturation of this transition. By suitable choice of chemical systems this low dimensional behavior can be experimentally approached.

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Shih, Hui-Ru, and H. S. Tzou. "Opto-Piezothermoelastic Constitutive Modeling of a New 2-D Photostrictive Composite Plate Actuator." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1759.

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Abstract Optical actuators can introduce non-contact remote actuation and control effect without any hard-wired connections. In this study, constitutive relations, general opto-piezo(electric)-thermo-elastic equations, and their one-dimensional (1D) form are formulated and applied to a new two-dimensional (2D) planar actuator and composite plates laminated with distributed photostrictive optical actuators. Photodeformation, pyroelectricity, and thermoelasticity are considered in the constitutive relations and coordinate transformations are used to transform the 1D local actuation characteristics to the 2D global actuator coordinate system. Mathematical model and system parameters are then calibrated with experimental data; analytical solution based simulation and experimental results are compared favorably. Thus, the proposed constitutive modeling and governing equations of distributed 2D optical actuators preserve natural photodeformation, pyroelectricity, and thermoelasticity characteristics and applicable to distributed control of 2D continuous systems.

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Nojima, S., M. Notomi, M. Nakao, and T. Tamamura. "Effects of Size Fluctuation on the Optical Properties of Very Narrow InGaAs/InP Quantum Well Wires." In Quantum Optoelectronics. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/qo.1993.qfa.2.

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The authors have succeeded in fabricating very narrow InGaAs/InP quantum well wires (QWWs with cross sections down to 50 Åx100 Å) by combining electron beam lithograhpy, reverse-mesa wet etching, and the subsequent overgrowth onto bare QWW structures.1 Moreover, the authors reported several optical properties of the QWWs thus fabricated which manifested the one dimensional confinement of the electron-hole system.1,2 In order to adequately draw on the potential of QWWs, it is essential, in addition to the fundamental qualities described above, to reduce the QWW size fluctuation.3 This is because great size-fluctuation leads to pronounced fluctuation in quantum levels and the resultant broadening of the otherwise sharp density of state spectrum. Considering this, it is urgent that the relationship between the size fluctuation and the characteristics of QWWs be clarified.

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Bigot, J. Y., M. T. Portella, R. W. Schoenlein, C. V. Shank, and J. E. Cunningham. "Two-Dimensional Carrier-Carrier Screening in a Quantum Well." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/up.1990.wa1.

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The phase coherence between an electron and the corresponding hole created during a band- to-band optical transition in a semiconductor diminishes with increasing carrier density. The rate at which such dephasing processes occur may however be reduced due to a screened interaction between the carriers. Since the screening between two given carriers is function of their environment, it is expected to change with the dimensionality D of the system. We report here measurements on the carrier-carrier screening behavior in a 2D system (a GaAs-GaA1As quantum well structure), performed by measuring the variation of the dephasing time with carrier density using a femtosecond photon echo technique [1]. We briefly discuss the results with respect to previous measurements made in a 3D system (a bulk sample of GaAs) [2].

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DiAngelo, Denis J., Keith A. Vossel, and Thomas H. Jansen. "A Multi-Body Optical Measurement System for the Study of Human Joint Motion." In ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0097.

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Abstract Human joint systems exhibit complex, coupled movement patterns. Various measurement devices have been developed to study human joint behavior. They include electromechanical, electromagnetic, and electro-optical systems; and radiographic techniques [Lim et al., 1997; Milne et al., 1996; Moeini et al., 1996]. When measuring global joint motion, accuracy of the system must be considered. Measures of “relative” joint motion depend on system resolution and repeatability. An improved three-dimensional (3-D) non-contact measurement system was develop to study human joint motion. System calibration for two-dimensional (2-D) analysis was performed. Application to the cervical spine is presented.

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Nanto, H., Y. Douguchi, J. Nishishita, M. Kadota, N. Kashiwagi, T. Shinkawa, and S. Nasu. "A Novel Erasable and Rewritable Optical Memory Utilizing Photostimulated Luminescence in Eu and Sm Co-doped SrS Phosphor Ceramics." In Symposium on Optical Memory. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/isom.1996.otub.9.

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New systems to optical memory, which are based on the photostimulated luminescence (PSL) phenomenon in electron trapping phosphor materials for optical storage, have been studied in the fields of optical parallel Boolean logic operation [1], two-dimensional optical associative memory [2] and optical neural networks [3,4], The electron trapping phosphor materials can emit different output photons that correlate spatially in intensity with input photons. Consequently, the phosphor materials can be used to store optical information as trapped electrons and the information stored can be read out by a laser beam scanning of the phosphor material. The unique features of the electron trapping phosphor materials that exhibit the PSL phenomenon provide the potential for high bit storage densities, high data transfer, and fast recovery speeds. [5] Important characteristics of a good electron trapping phosphor materials for optical memory are high PSL brightness for low noise, short luminescent lifetime for minimum readout time, and low light scattering for high bit densities. Especially, the electron trapping phosphor materials using transparent thin film provides an efficient PSL and low light scattering.

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Miller, John, Wanyoung Jang, and Chris Dames. "Thermal Rectification by Ballistic Phonons." In ASME 2008 3rd Energy Nanotechnology International Conference collocated with the Heat Transfer, Fluids Engineering, and Energy Sustainability Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/enic2008-53064.

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In analogy to the asymmetric transport of electricity in a familiar electrical diode, a thermal rectifier transports heat more favorably in one direction than in the reverse direction. One approach to thermal rectification is asymmetric scattering of phonons and/or electrons, similar to suggestions in the literature for a sawtooth nanowire [1] or 2-dimensional electron gas with triangular scatterers [2]. To model the asymmetric heat transport in such nanostructures, we have used phonon ray-tracing, focusing on characteristic lengths that are small compared to the mean free path of phonons in bulk. To calculate the heat transfer we use a transmission-based (Landauer-Buttiker) method. The system geometry is described by a four-dimensional transfer function that depends on the position and angle of phonon emission and absorption from each of two contacts. At small temperature gradients, the phonon distribution function is very close to the usual isotropic equilibrium (Bose-Einstein) distribution, and there is no thermal rectification. In contrast, at large temperature gradients, the anisotropy in the phonon distribution function becomes significant, and the resulting heat flux vs. temperature curve (analogous to I-V curve of a diode) reveals large thermal rectification.

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Reports on the topic "2- dimensional electron system (2 DES)"

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Elbaum, Michael, and Peter J. Christie. Type IV Secretion System of Agrobacterium tumefaciens: Components and Structures. United States Department of Agriculture, March 2013. http://dx.doi.org/10.32747/2013.7699848.bard.

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Objectives: The overall goal of the project was to build an ultrastructural model of the Agrobacterium tumefaciens type IV secretion system (T4SS) based on electron microscopy, genetics, and immunolocalization of its components. There were four original aims: Aim 1: Define the contributions of contact-dependent and -independent plant signals to formation of novel morphological changes at the A. tumefaciens polar membrane. Aim 2: Genetic basis for morphological changes at the A. tumefaciens polar membrane. Aim 3: Immuno-localization of VirB proteins Aim 4: Structural definition of the substrate translocation route. There were no major revisions to the aims, and the work focused on the above questions. Background: Agrobacterium presents a unique example of inter-kingdom gene transfer. The process involves cell to cell transfer of both protein and DNA substrates via a contact-dependent mechanism akin to bacterial conjugation. Transfer is mediated by a T4SS. Intensive study of the Agrobacterium T4SS has made it an archetypal model for the genetics and biochemistry. The channel is assembled from eleven protein components encoded on the B operon in the virulence region of the tumor-inducing plasmid, plus an additional coupling protein, VirD4. During the course of our project two structural studies were published presenting X-ray crystallography and three-dimensional reconstruction from electron microscopy of a core complex of the channel assembled in vitro from homologous proteins of E. coli, representing VirB7, VirB9, and VirB10. Another study was published claiming that the secretion channels in Agrobacterium appear on helical arrays around the membrane perimeter and along the entire length of the bacterium. Helical arrangements in bacterial membranes have since fallen from favor however, and that finding was partially retracted in a second publication. Overall, the localization of the T4SS within the bacterial membranes remains enigmatic in the literature, and we believe that our results from this project make a significant advance. Summary of achievements : We found that polar inflations and other membrane disturbances relate to the activation conditions rather than to virulence protein expression. Activation requires low pH and nutrient-poor medium. These stress conditions are also reflected in DNA condensation to varying degrees. Nonetheless, they must be considered in modeling the T4SS as they represent the relevant conditions for its expression and activity. We identified the T4SS core component VirB7 at native expression levels using state of the art super-resolution light microscopy. This marker of the secretion system was found almost exclusively at the cell poles, and typically one pole. Immuno-electron microscopy identified the protein at the inner membrane, rather than at bridges across the inner and outer membranes. This suggests a rare or transient assembly of the secretion-competent channel, or alternatively a two-step secretion involving an intermediate step in the periplasmic space. We followed the expression of the major secreted effector, VirE2. This is a single-stranded DNA binding protein that forms a capsid around the transferred oligonucleotide, adapting the bacterial conjugation to the eukaryotic host. We found that over-expressed VirE2 forms filamentous complexes in the bacterial cytoplasm that could be observed both by conventional fluorescence microscopy and by correlative electron cryo-tomography. Using a non-retentive mutant we observed secretion of VirE2 from bacterial poles. We labeled the secreted substrates in vivo in order detect their secretion and appearance in the plant cells. However the low transfer efficiency and significant background signal have so far hampered this approach.

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Yazıcı, Devrim, and Hakan Sert. Symmetry Reduction of Asymmetric Heavenly Equation and 2+1-Dimensional Bi-Hamiltonian System. GIQ, 2014. http://dx.doi.org/10.7546/giq-15-2014-309-317.

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Yazici, Devrim, and Hakan Sert. Symmetry Reduction of Asymmetric Heavenly Equation and 2+1-Dimensional Bi-Hamiltonian System. Jgsp, 2014. http://dx.doi.org/10.7546/jgsp-34-2014-87-96.

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Adams, Sophie, Lisa Diamond, Tara Esterl, Peter Fröhlich, Rishabh Ghotge, Regina Hemm, Ida Marie Henriksen, et al. Social License to Automate: Emerging Approaches to Demand Side Management. IEA User-Centred Energy Systems Technology Collaboration Programme, October 2021. http://dx.doi.org/10.47568/4xr122.

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The Social License to Automate Task has investigated the social dimensions of user engagement with automated technologies in energy systems to understand how end-user trust to automate is built and maintained in different jurisdictions and cultural settings. The rapid uptake of renewable energy systems will require new automated technologies to balance energy supplies. Some developers are looking to locate these in households where energy is being used. This saves moving the energy from centralised generation sites (remote hydro, solar or wind). This report details the findings from a 2 year project with 16 researchers in 6 countries, 26 Case studies spanning electric vehicles, home and precinct batteries, air conditioners and other heat pumps.

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Author, Unknown. PR-328-6352-R01 LaserScan Mapping and Reporting of Plain Dents in Support of PRCI - Phase 2. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), September 2007. http://dx.doi.org/10.55274/r0012169.

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As part of the PRCI sponsored project (MD 1-2), ten defects were introduced on a three-meter section of a 30-inch pipe. Detailed mapping of all the defects was performed using a 3D LaserScan system by Applus RTD. The objective of the scan was to get a detailed, high resolution, high density, three-dimensional representation of the defects and to provide some critical metrics about the defects.

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Wilson, D., Daniel Breton, Lauren Waldrop, Danney Glaser, Ross Alter, Carl Hart, Wesley Barnes, et al. Signal propagation modeling in complex, three-dimensional environments. Engineer Research and Development Center (U.S.), April 2021. http://dx.doi.org/10.21079/11681/40321.

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The Signal Physics Representation in Uncertain and Complex Environments (SPRUCE) work unit, part of the U.S. Army Engineer Research and Development Center (ERDC) Army Terrestrial-Environmental Modeling and Intelligence System (ARTEMIS) work package, focused on the creation of a suite of three-dimensional (3D) signal and sensor performance modeling capabilities that realistically capture propagation physics in urban, mountainous, forested, and other complex terrain environments. This report describes many of the developed technical capabilities. Particular highlights are (1) creation of a Java environmental data abstraction layer for 3D representation of the atmosphere and inhomogeneous terrain that ingests data from many common weather forecast models and terrain data formats, (2) extensions to the Environmental Awareness for Sensor and Emitter Employment (EASEE) software to enable 3D signal propagation modeling, (3) modeling of transmitter and receiver directivity functions in 3D including rotations of the transmitter and receiver platforms, (4) an Extensible Markup Language/JavaScript Object Notation (XML/JSON) interface to facilitate deployment of web services, (5) signal feature definitions and other support for infrasound modeling and for radio-frequency (RF) modeling in the very high frequency (VHF), ultra-high frequency (UHF), and super-high frequency (SHF) frequency ranges, and (6) probabilistic calculations for line-of-sight in complex terrain and vegetation.

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Alexander and Kiefner. L51554 Field Observations on the Two-Phase Hovenweep CO2 Gathering System During Summer Operation. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), January 1988. http://dx.doi.org/10.55274/r0010290.

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While laboratory-scale studies of single-phase flow have resulted in good correlations for the design of large-diameter pipeline systems, similar approaches for two-phase flow have not been as useful. Although theoretical modeling and simulation of single-phase turbulent flow has not yet been accomplished, empirical observation of many small-scale examples has lead to effective correlations through dimensional analysis. These correlations for a single-phase often do scale-up adequately for design of pipelines. However, when an additional phase is present, this approach has not worked well. It is likely that a better understanding of the fundamental interaction of two-turbulent phases will be necessary if small-scale studies are to be used for the design of large, high-pressure pipeline systems. A more immediate way of gaining some knowledge of two-phase flow in large diameter pipes of the complexity present in the field is to over-design a pipeline system and construct it, field tune it to specifications, then observe its behavior. This is obviously a risky and expensive approach. However, many such systems have been constructed. It is on these successful two-phase pipeline systems that our attention should be focused in the immediate future if we are to improve two-phase pipeline design now of new but similar systems. Such is the focus of this study of the Hovenweep CO2 Gathering System. The Hovenweep CO2 Gathering System was selected for study as a pipeline system that could add to the knowledge of the nature of steady-state two-phase flow in large diameter high pressure pipeline systems with hilly terrain. Characterization includes measurement of the following variables: 1. gas and liquid flow rates; 2. typical gas and liquid compositions; 3. liquid volume fractions; 4. pressure drop across each test segment; 5. temperature.

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Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova, and Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7604286.bard.

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The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.

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Tzfira, Tzvi, Michael Elbaum, and Sharon Wolf. DNA transfer by Agrobacterium: a cooperative interaction of ssDNA, virulence proteins, and plant host factors. United States Department of Agriculture, December 2005. http://dx.doi.org/10.32747/2005.7695881.bard.

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Agrobacteriumtumefaciensmediates genetic transformation of plants. The possibility of exchanging the natural genes for other DNA has led to Agrobacterium’s emergence as the primary vector for genetic modification of plants. The similarity among eukaryotic mechanisms of nuclear import also suggests use of its active elements as media for non-viral genetic therapy in animals. These considerations motivate the present study of the process that carries DNA of bacterial origin into the host nucleus. The infective pathway of Agrobacterium involves excision of a single-stranded DNA molecule (T-strand) from the bacterial tumor-inducing plasmid. This transferred DNA (T-DNA) travels to the host cell cytoplasm along with two virulence proteins, VirD2 and VirE2, through a specific bacteriumplant channel(s). Little is known about the precise structure and composition of the resulting complex within the host cell and even less is known about the mechanism of its nuclear import and integration into the host cell genome. In the present proposal we combined the expertise of the US and Israeli labs and revealed many of the biophysical and biological properties of the genetic transformation process, thus enhancing our understanding of the processes leading to nuclear import and integration of the Agrobacterium T-DNA. Specifically, we sought to: I. Elucidate the interaction of the T-strand with its chaperones. II. Analyzing the three-dimensional structure of the T-complex and its chaperones in vitro. III. Analyze kinetics of T-complex formation and T-complex nuclear import. During the past three years we accomplished our goals and made the following major discoveries: (1) Resolved the VirE2-ssDNA three-dimensional structure. (2) Characterized VirE2-ssDNA assembly and aggregation, along with regulation by VirE1. (3) Studied VirE2-ssDNA nuclear import by electron tomography. (4) Showed that T-DNA integrates via double-stranded (ds) intermediates. (5) Identified that Arabidopsis Ku80 interacts with dsT-DNA intermediates and is essential for T-DNA integration. (6) Found a role of targeted proteolysis in T-DNA uncoating. Our research provide significant physical, molecular, and structural insights into the Tcomplex structure and composition, the effect of host receptors on its nuclear import, the mechanism of T-DNA nuclear import, proteolysis and integration in host cells. Understanding the mechanical and molecular basis for T-DNA nuclear import and integration is an essential key for the development of new strategies for genetic transformation of recalcitrant plant species. Thus, the knowledge gained in this study can potentially be applied to enhance the transformation process by interfering with key steps of the transformation process (i.e. nuclear import, proteolysis and integration). Finally, in addition to the study of Agrobacterium-host interaction, our research also revealed some fundamental insights into basic cellular mechanisms of nuclear import, targeted proteolysis, protein-DNA interactions and DNA repair.

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Kirchhoff, Helmut, and Ziv Reich. Protection of the photosynthetic apparatus during desiccation in resurrection plants. United States Department of Agriculture, February 2014. http://dx.doi.org/10.32747/2014.7699861.bard.

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In this project, we studied the photosynthetic apparatus during dehydration and rehydration of the homoiochlorophyllous resurrection plant Craterostigmapumilum (retains most of the photosynthetic components during desiccation). Resurrection plants have the remarkable capability to withstand desiccation, being able to revive after prolonged severe water deficit in a few days upon rehydration. Homoiochlorophyllous resurrection plants are very efficient in protecting the photosynthetic machinery against damage by reactive oxygen production under drought. The main purpose of this BARD project was to unravel these largely unknown protection strategies for C. pumilum. In detail, the specific objectives were: (1) To determine the distribution and local organization of photosynthetic protein complexes and formation of inverted hexagonal phases within the thylakoid membranes at different dehydration/rehydration states. (2) To determine the 3D structure and characterize the geometry, topology, and mechanics of the thylakoid network at the different states. (3) Generation of molecular models for thylakoids at the different states and study the implications for diffusion within the thylakoid lumen. (4) Characterization of inter-system electron transport, quantum efficiencies, photosystem antenna sizes and distribution, NPQ, and photoinhibition at different hydration states. (5) Measuring the partition of photosynthetic reducing equivalents between the Calvin cycle, photorespiration, and the water-water cycle. At the beginning of the project, we decided to use C. pumilum instead of C. wilmsii because the former species was available from our collaborator Dr. Farrant. In addition to the original two dehydration states (40 relative water content=RWC and 5% RWC), we characterized a third state (15-20%) because some interesting changes occurs at this RWC. Furthermore, it was not possible to detect D1 protein levels by Western blot analysis because antibodies against other higher plants failed to detect D1 in C. pumilum. We developed growth conditions that allow reproducible generation of different dehydration and rehydration states for C. pumilum. Furthermore, advanced spectroscopy and microscopy for C. pumilum were established to obtain a detailed picture of structural and functional changes of the photosynthetic apparatus in different hydrated states. Main findings of our study are: 1. Anthocyan accumulation during desiccation alleviates the light pressure within the leaves (Fig. 1). 2. During desiccation, stomatal closure leads to drastic reductions in CO2 fixation and photorespiration. We could not identify alternative electron sinks as a solution to reduce ROS production. 3. On the supramolecular level, semicrystalline protein arrays were identified in thylakoid membranes in the desiccated state (see Fig. 3). On the electron transport level, a specific series of shut downs occur (summarized in Fig. 2). The main events include: Early shutdown of the ATPase activity, cessation of electron transport between cyt. bf complex and PSI (can reduce ROS formation at PSI); at higher dehydration levels uncoupling of LHCII from PSII and cessation of electron flow from PSII accompanied by crystal formation. The later could severe as a swift PSII reservoir during rehydration. The specific order of events in the course of dehydration and rehydration discovered in this project is indicative for regulated structural transitions specifically realized in resurrection plants. This detailed knowledge can serve as an interesting starting point for rationale genetic engineering of drought-tolerant crops.

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