Academic literature on the topic 'Two-dimensional alloys'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Two-dimensional alloys.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Two-dimensional alloys"
1
Oehme, Michael, Erich Kasper, David Weißhaupt, Eric Sigle, Tim Hersperger, Maurice Wanitzek, and Daniel Schwarz. "Two-dimensional hole gases in SiGeSn alloys." Semiconductor Science and Technology 37, no. 5 (April 8, 2022): 055009. http://dx.doi.org/10.1088/1361-6641/ac61fe.
Full textAbstract:
Abstract Two-dimensional hole gases are demonstrated in modulation doped Si x Ge1−x−y Sn y quantum wells (QWs), which are embedded in Si0.2Ge0.8 barrier layers. The modulation doped QW structures are fabricated with molecular beam epitaxy on a thin (100 nm) virtual SiGe substrate on a (001) oriented Si substrate. The virtual substrate (VS) concept utilizes the Si diffusion into an as- grown thin, strain relaxed Ge layer during a following annealing step. The lateral lattice spacing of the SiGe-VS could be varied by the annealing temperature in the range between 830 °C and 860 °C. Half-hour anneal at 848 °C results in nearly strain free growth for the following Si0.2Ge0.8 barrier layer. Boron doping above an undoped 10 nm spacer on top of the 15 nm QW provides a reservoir for hole transfer from the barrier to the well. Electrical conductivity, sheet hole density ps and mobility are measured as function of temperature. In all investigated Si x Ge1−x−y Sn y channels the Hall measurements show the typical freeze out of holes outside the QW. Alloy scattering dominates the low-temperature mobility by adding Sn or Si to the Ge reference well. A linear relationship for the charge transfer from the modulation doping into the undoped Si x Ge1−x−y Sn y channel as function of the lattice mismatch between the channel material and the matrix material could be found at low-temperatures (8 K). An analytical model for this charge transfer confirms the nearly linear relationship by considering the triangular shape of the potential in modulation doped QW structures.
2
Tongay, Sefaattin, Deepa S. Narang, Jun Kang, Wen Fan, Changhyun Ko, Alexander V. Luce, Kevin X. Wang, et al. "Two-dimensional semiconductor alloys: Monolayer Mo1−xWxSe2." Applied Physics Letters 104, no. 1 (January 6, 2014): 012101. http://dx.doi.org/10.1063/1.4834358.
Full text
3
WAKAYAMA, Yutaka, Anirban BANDYOPADHYAY, Esther BARRENA, and Dimas G. de OTEYZA. "Binary Molecules for Two-dimensional Molecular Alloys." Hyomen Kagaku 29, no. 7 (2008): 421–26. http://dx.doi.org/10.1380/jsssj.29.421.
Full text
4
Bendavid, Leah Isseroff, Yilin Zhong, Ziyi Che, and Yagmur Konuk. "Strain-engineering in two-dimensional transition metal dichalcogenide alloys." Journal of Applied Physics 132, no. 22 (December 14, 2022): 225303. http://dx.doi.org/10.1063/5.0120484.
Full textAbstract:
Two-dimensional (2D) transition metal dichalcogenides (TMDs) are attractive semiconductors for use in electronic, optoelectronic, and spintronic devices. This study examines how the electronic properties of 2D TMDs can be tuned for specific applications through a combination of alloying and applying strain. Group VIB TMDs (MoS2, MoSe2, WS2, and WSe2) are alloyed by mixing in the metal or chalcogen sublattices. Density functional theory is used to model the structures of the alloys at varying compositions and examine the electronic structure of the alloys under biaxial tensile and compressive strain. Alloying results in the continuous monotonic tuning of the direct bandgap between the limits of the pure components, with low bowing coefficients for all alloys. Applying strain results in a transition of the bandgap from direct to indirect at low values of tensile strain and higher values of compressive strain. Strain can also be used to increase or decrease the bandgap with low compressive strain or tensile strain, respectively. The shift rate, or the rate at which the bandgap changes with applied strain, changes monotonically with alloy composition. MoS2 is identified as the 2D TMD with the highest shift rate.
5
JIN, Yeongrok, and Jaekwang LEE*. "Study of Two-dimensional Transition Metal Chalcogenide Alloys." New Physics: Sae Mulli 71, no. 3 (March 31, 2021): 225–29. http://dx.doi.org/10.3938/npsm.71.225.
Full text
6
Attard, Gary A., and David A. King. "Two-dimensional surface alloys: Copper on W(100)." Surface Science 188, no. 3 (October 1987): 589–98. http://dx.doi.org/10.1016/s0039-6028(87)80207-8.
Full text
7
Attard, Gary A., and David A. King. "Two-dimensional surface alloys: Copper on W(100)." Surface Science Letters 188, no. 3 (October 1987): A370. http://dx.doi.org/10.1016/0167-2584(87)90601-3.
Full text
8
Zhou, Yang, Zhi-Xin Guo, Hai-Yuan Cao, Shi-You Chen, Hong-Jun Xiang, and Xin-Gao Gong. "Thermal conductivity of disordered two-dimensional binary alloys." Nanoscale 8, no. 41 (2016): 17815–19. http://dx.doi.org/10.1039/c6nr04651g.
Full text
9
Wang, Xinsheng, Liming Xie, and Jin Zhang. "Preparation, Structure and Properties of Two-dimensional Semiconductor Alloys." Acta Chimica Sinica 73, no. 9 (2015): 886. http://dx.doi.org/10.6023/a15030187.
Full text
10
Appino, C., C. Beatrice, E. Ferrara, M. Pelazza, and F. Fiorillo. "One- and two-dimensional magnetization processes in amorphous alloys." Journal of Applied Physics 81, no. 8 (April 15, 1997): 4045–47. http://dx.doi.org/10.1063/1.364873.
Full textDissertations / Theses on the topic "Two-dimensional alloys"
1
Widmer-Cooper, Asaph. "Structure and dynamics in two-dimensional glass-forming alloys." Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1320.
Full textAbstract:
The glass-transition traverses continuously from liquid to solid behaviour, yet the role of structure in this large and gradual dynamic transition is poorly understood. This thesis presents a theoretical study of the relationship between structure and dynamics in two-dimensional glass-forming alloys, and provides new tools and real-space insight into the relationship at a microscopic level. The work is divided into two parts. Part I is concerned with the role of structure in the appearance of spatially heterogeneous dynamics in a supercooled glass-forming liquid. The isoconfigurational ensemble method is introduced as a general tool for analysing the effect that a configuration has on the subsequent particle motion, and the dynamic propensity is presented as the aspect of structural relaxation that can be directly related to microscopic variations in the structure. As the temperature is reduced, the spatial distribution of dynamic propensity becomes increasingly heterogeneous. This provides the first direct evidence that the development of spatially heterogeneous dynamics in a fragile glass-former is related to spatial variations in the structure. The individual particle motion also changes from Gaussian to non- Gaussian as the temperature is reduced, i.e. the configuration expresses its character more and more intermittently. The ability of several common measures of structure and a measure of structural ‘looseness’ to predict the spatial distribution of dynamic propensity are then tested. While the local coordination environment, local potential energy, and local free volume show some correlation with propensity, they are unable to predict its spatial variation. Simple coarse-graining does not help either. These results cast doubt on the microscopic basis of theories of the glass transition that are based purely on concepts of free volume or local potential energy. In sharp contrast, a dynamic measure of structural ‘looseness’ - an isoconfigurational single-particle Debye-Waller (DW) factor - is able to predict the spatial distribution of propensity in the supercooled liquid. This provides the first microscopic evidence for previous correlations found between short- and long-time dynamics in supercooled liquids. The spatial distribution of the DW factor changes rapidly in the supercooled liquid and suggests a picture of structural relaxation that is inconsistent with simple defect diffusion. Overall, the work presented in Part I provides a real-space description of the transition from structure-independent to structure-dependent dynamics, that is complementary to the configuration-space description provided by the energy landscape picture of the glass transition. In Part II, an investigation is presented into the effect of varying the interparticle potential on the phase behaviour of the binary soft-disc model. This represents a different approach to studying the role of structure in glass-formation, and suggests many interesting directions for future work. The structural and dynamic properties of six different systems are characterised, and some comparisons are made between them. A wide range of alloy-like structures are formed, including substitutionally ordered crystals, amorphous solids, and multiphase materials. Approximate phase diagrams show that glass-formation generally occurs between competing higher symmetry structures. This work identifies two new glass-forming systems with effective chemical ordering and substantially different short- and medium-range structure compared to the glassformer studied in Part I. These represent ideal candidates for extending the study presented in Part I. There also appears to be a close connection between quasicrystal and glass-formation in 2D via random-tiling like structures. This may help explain the experimental observation that quasicrystals sometimes vitrify on heating. The alignment of asymmetric unit cells is found to be the rate-limiting step in the crystal nucleation and growth of a substitutionally ordered crystal, and another system shows amorphous-crystal coexistence and appears highly stable to complete phase separation. The generality of these results and their implications for theoretical descriptions of the glass transition are also discussed.
2
Widmer-Cooper, Asaph. "Structure and dynamics in two-dimensional glass-forming alloys." Science. School of Chemistry, 2006. http://hdl.handle.net/2123/1320.
Full textAbstract:
Doctor of Philosophy (PhD)The glass-transition traverses continuously from liquid to solid behaviour, yet the role of structure in this large and gradual dynamic transition is poorly understood. This thesis presents a theoretical study of the relationship between structure and dynamics in two-dimensional glass-forming alloys, and provides new tools and real-space insight into the relationship at a microscopic level. The work is divided into two parts. Part I is concerned with the role of structure in the appearance of spatially heterogeneous dynamics in a supercooled glass-forming liquid. The isoconfigurational ensemble method is introduced as a general tool for analysing the effect that a configuration has on the subsequent particle motion, and the dynamic propensity is presented as the aspect of structural relaxation that can be directly related to microscopic variations in the structure. As the temperature is reduced, the spatial distribution of dynamic propensity becomes increasingly heterogeneous. This provides the first direct evidence that the development of spatially heterogeneous dynamics in a fragile glass-former is related to spatial variations in the structure. The individual particle motion also changes from Gaussian to non- Gaussian as the temperature is reduced, i.e. the configuration expresses its character more and more intermittently. The ability of several common measures of structure and a measure of structural ‘looseness’ to predict the spatial distribution of dynamic propensity are then tested. While the local coordination environment, local potential energy, and local free volume show some correlation with propensity, they are unable to predict its spatial variation. Simple coarse-graining does not help either. These results cast doubt on the microscopic basis of theories of the glass transition that are based purely on concepts of free volume or local potential energy. In sharp contrast, a dynamic measure of structural ‘looseness’ - an isoconfigurational single-particle Debye-Waller (DW) factor - is able to predict the spatial distribution of propensity in the supercooled liquid. This provides the first microscopic evidence for previous correlations found between short- and long-time dynamics in supercooled liquids. The spatial distribution of the DW factor changes rapidly in the supercooled liquid and suggests a picture of structural relaxation that is inconsistent with simple defect diffusion. Overall, the work presented in Part I provides a real-space description of the transition from structure-independent to structure-dependent dynamics, that is complementary to the configuration-space description provided by the energy landscape picture of the glass transition. In Part II, an investigation is presented into the effect of varying the interparticle potential on the phase behaviour of the binary soft-disc model. This represents a different approach to studying the role of structure in glass-formation, and suggests many interesting directions for future work. The structural and dynamic properties of six different systems are characterised, and some comparisons are made between them. A wide range of alloy-like structures are formed, including substitutionally ordered crystals, amorphous solids, and multiphase materials. Approximate phase diagrams show that glass-formation generally occurs between competing higher symmetry structures. This work identifies two new glass-forming systems with effective chemical ordering and substantially different short- and medium-range structure compared to the glassformer studied in Part I. These represent ideal candidates for extending the study presented in Part I. There also appears to be a close connection between quasicrystal and glass-formation in 2D via random-tiling like structures. This may help explain the experimental observation that quasicrystals sometimes vitrify on heating. The alignment of asymmetric unit cells is found to be the rate-limiting step in the crystal nucleation and growth of a substitutionally ordered crystal, and another system shows amorphous-crystal coexistence and appears highly stable to complete phase separation. The generality of these results and their implications for theoretical descriptions of the glass transition are also discussed.
3
Park, Juhong. "Fabrication of Large-Scale and Thickness-Modulated Two-Dimensional Transition Metal Dichalcogenides [2D TMDs] Nanolayers." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1505271/.
Full textAbstract:
This thesis describes the fabrication and characterization of two-dimensional transition dichalcogenides (2D TMDs) nanolayers for various applications in electronic and opto-electronic devices applications. In Chapter 1, crystal and optical structure of TMDs materials are introduced. Many TMDs materials reveal three structure polytypes (1T, 2H, and 3R). The important electronic properties are determined by the crystal structure of TMDs; thus, the information of crystal structure is explained. In addition, the detailed information of photon vibration and optical band gap structure from single-layer to bulk TMDs materials are introduced in this chapter. In Chapter 2, detailed information of physical properties and synthesis techniques for molybdenum disulfide (MoS2), tungsten disulfide (WS2), and molybdenum ditelluride (MoTe2) nanolayers are explained. The three representative crystal structures are trigonal prismatic (hexagonal, H), octahedral (tetragonal, T), and distorted structure (Tʹ). At room temperature, the stable structure of MoS2 and WS2 is semiconducting 2H phase, and MoTe2 can reveal both 2H (semiconducting phase) and 1Tʹ (semi-metallic phase) phases determined by the existence of strains. In addition, the pros and cons of the synthesis techniques for nanolayers are discussed. In Chapter 3, the topic of synthesized large-scale MoS2, WS2, and MoTe2 films is considered. For MoS2 and WS2 films, the layer thickness is modulated from single-layer to multi-layers. The few-layer MoTe2 film is synthesized with two different phases (2H or 1Tʹ). The all TMDs films are fabricated using two-step chemical vapor deposition (CVD) method. The analyses of atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL), and Raman spectroscopy confirm that the synthesis of high crystalline MoS2, WS2, and MoTe2 films are successful. The electronic properties of both MoS2 and WS2 exhibit a p-type conduction with relatively high field effect mobility and current on/off ratio. In Chapter 4, vertically-stacked few-layer MoS2/WS2 heterostructures on SiO2/Si and flexible polyethylene terephthalate (PET) substrates is presented. Detailed structural characterizations by Raman spectroscopy and high-resolution/scanning transmission electron microscopy (HRTEM/STEM) show the structural integrity of two distinct 2D TMD layers with atomically sharp van der Waals (vdW) heterointerfaces. Electrical transport measurements of the MoS2/WS2 heterostructure reveal diode-like behavior with current on/off ratio of ~ 104. In Chapter 5, optically uniform and scalable single-layer Mo1-xWxS2 alloys are synthesized by a two-step CVD method followed by a laser thinning. Post laser treatment is presented for etching of few-layer Mo1-xWxS2 alloys down to single-layer alloys. The optical band gap is controlled from 1.871 to 1.971 eV with the variation in the tungsten (W) content, x = 0 to 1. PL and Raman mapping analyses confirm that the laser-thinning of the Mo1-xWxS2 alloys is a self-limiting process caused via heat dissipation to SiO2/Si substrate, resulting in fabrication of spatially uniform single-layer Mo1-xWxS2 alloy films.
4
Yuhara, J., M. Schmid, and P. Varga. "Two-dimensional alloy of immiscible metals: Single and binary monolayer films of Pb and Sn on Rh(111)." The American Physical Society, 2003. http://hdl.handle.net/2237/7113.
Full text
5
Pavlovitch, André. "Problemes de structure et de defauts de structure dans les pavages aperiodiques bi-dimensionnels (quasi-cristaux)." Paris 6, 1988. http://www.theses.fr/1988PA066467.
Full textAbstract:
Etude geometrique des proprietes structurales des pavages de penrose bidimensionnels servant de base aux modeles des phases decagonales d'alliages d'aluminium-manganese. Etude de la statistique de propagation privilegies des phasons: les tubes. Description des pavages generalises, obtenus par transformation structurale
6
MEDEIROS, Rex Antonio da Costa. "Zero-Error capacity of quantum channels." Universidade Federal de Campina Grande, 2008. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1320.
Full textAbstract:
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-08-01T21:11:37Z
No. of bitstreams: 1
REX ANTONIO DA COSTA MEDEIROS - TESE PPGEE 2008..pdf: 1089371 bytes, checksum: ea0c95501b938e0d466779a06faaa4f6 (MD5)Made available in DSpace on 2018-08-01T21:11:37Z (GMT). No. of bitstreams: 1 REX ANTONIO DA COSTA MEDEIROS - TESE PPGEE 2008..pdf: 1089371 bytes, checksum: ea0c95501b938e0d466779a06faaa4f6 (MD5) Previous issue date: 2008-05-09
Nesta tese, a capacidade erro-zero de canais discretos sem memória é generalizada para canais quânticos. Uma nova capacidade para a transmissão de informação clássica através de canais quânticos é proposta. A capacidade erro-zero de canais quânticos (CEZQ) é definida como sendo a máxima quantidade de informação por uso do canal que pode ser enviada através de um canal quântico ruidoso, considerando uma probabilidade de erro igual a zero. O protocolo de comunicação restringe palavras-código a produtos tensoriais de estados quânticos de entrada, enquanto que medições coletivas entre várias saídas do canal são permitidas. Portanto, o protocolo empregado é similar ao protocolo de Holevo-Schumacher-Westmoreland. O problema de encontrar a CEZQ é reformulado usando elementos da teoria de grafos. Esta definição equivalente é usada para demonstrar propriedades de famílias de estados quânticos e medições que atingem a CEZQ. É mostrado que a capacidade de um canal quântico num espaço de Hilbert de dimensão d pode sempre ser alcançada usando famílias compostas de, no máximo,d estados puros. Com relação às medições, demonstra-se que medições coletivas de von Neumann são necessárias e suficientes para alcançar a capacidade. É discutido se a CEZQ é uma generalização não trivial da capacidade erro-zero clássica. O termo não trivial refere-se a existência de canais quânticos para os quais a CEZQ só pode ser alcançada através de famílias de estados quânticos não-ortogonais e usando códigos de comprimento maior ou igual a dois. É investigada a CEZQ de alguns canais quânticos. É mostrado que o problema de calcular a CEZQ de canais clássicos-quânticos é puramente clássico. Em particular, é exibido um canal quântico para o qual conjectura-se que a CEZQ só pode ser alcançada usando uma família de estados quânticos não-ortogonais. Se a conjectura é verdadeira, é possível calcular o valor exato da capacidade e construir um código de bloco quântico que alcança a capacidade. Finalmente, é demonstrado que a CEZQ é limitada superiormente pela capacidade de Holevo-Schumacher-Westmoreland.
7
"Synthesis of Two-Dimensional Metal-Organic Frameworks and their Alloys." Master's thesis, 2020. http://hdl.handle.net/2286/R.I.57338.
Full textAbstract:
abstract: Metal-organic frameworks have made a feature in the cutting-edge technology with a wide variety of applications because they are the new material candidate as adsorbent or membrane with high surface area, various pore sizes, and highly tunable framework functionality properties. The emergence of two-dimensional (2D) metal-organic frameworks has surged an outburst of intense research to understand the feasible synthesis and exciting material properties of these class of materials. Despite their potential, studies to date show that it is extremely challenging to synthesize and manufacture 2D MOF at large scales with ultimate control over crystallinity and thickness.
The field of research to date has produced various synthesis routes which can further be used to design 2D materials with a range of organic ligands and metal linkers. This thesis seeks to extend these design rules to demonstrate the competitive growth of two- dimensional (2D) metal-organic frameworks(MOF) and their alloys to predict which ligands and metals can be combined, study the intercalation of Bromine in these frameworks and their alloys which leads to the discovery of reduced band gap in the layered MOF alloy.
In this study it has been shown that the key factor in achieving layered 2D MOFs and it relies on the use of carefully engineered ligands to terminate the out-of-plane sites on metal clusters thereby eliminating strong interlayer hydrogen bond formation.
The major contribution of pyridine is to replace interlayer hydrogen bonding or other weak chemical bonds. Overall results establish an entirely new synthesis method for producing highly crystalline and scalable 2D MOFs and their alloys. Bromine intercalation merits future studies on band gap engineering in these layered materials.Dissertation/Thesis
Masters Thesis Chemical Engineering 2020
8
Chen, Jing-Yin, and 陳靜吟. "Quantum Transport of Two and Three Dimensional Copper-Germanium Alloys in the Weakly Disorded Regime." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/29624311471563421787.
Full textAbstract:
碩士國立交通大學
電子物理系
89
The electronic conduction in disordered system has been studied both theoretically and experimentally for decades. In weakly disordered regime, both weak localization and electron-electron interaction can describe well many experimental results such as temperature dependence of resistivity, magnetoresistance, and so on. In this work, we have studied the effects of the degree of disorder on electronic properties in CuGe samples. We have made a series of CuxGe100-x (42dxd92) alloys using arc-melting technique. For each alloy, a series of CuxGe100-x samples with different thickness were made by thermal evaporation. The degree of disorder decreases with increasing x, the relative molar concentration of Cu, systematically. Temperature dependence of resistances of all samples were measured using 4 probe AC measurements. The relation between resistivity and temperature reveals the dimensionality of the CuxGe100-x (42dxd92) sample. We have measured the magnetoresistances of both two-dimensional samples and three-dimensional samples in temperature range between 0.3K and 20K and in magnetic fields up to 4 Tesla. Fits to the weak localization theory allow us to obtain the spin-orbit scattering rate 1/tso and the temperature dependent inelastic scattering rate 1/tin. For all samples, 1/tso is temperature independent and increases with the increasing degree of disorder of samples. tin grows with decreasing temperature resulting in enhancement of localization effect. Moreover, it follows that 1/tin µ ATP. In 3-D system, the inelastic scattering mainly comes from the electron-phonon scattering. We found the temperature exponent p is in between 1.6 and 3. In 2-D samples, the temperature exponent p is in between 2 and 3. Furthermore, tin decreases with increasing disorder resulting in the reduction of localization effect.
9
(10723164), Suki N. Zhang. "Electronic Application of Two Dimensional Materials." Thesis, 2021.
Find full textAbstract:
Recent advances in atomically thin two-dimensional materials have led to various promising technologies such as nanoelectronics, sensing, energy storage, and optoelectronics applications. Graphene with sp2-bonded carbon atoms densely packed in a honeycomb crystal lattice has attracted tremendous interest with excellent electrical, optical, mechanical, and chemical properties. In this work, graphene’s mechanical properties, chemical properties, and piezoelectric properties are explored as graphene is implemented in the automotive electrical distribution system. Graphene is useful in friction reduction, corrosion protection, and piezoelectric energy harvesting cell improvement. Besides graphene, transition metal dichalcogenides (TMDs), which are the metal atoms sandwiched between two chalcogen atoms, have also attracted much attention. Unlike graphene, many TMDs are semiconductors in nature and possess enormous potential to be used as a potential channel material in ultra-scaled field-effect transistors (FETs). In this work, chemical doping strategies are explored for the tunnel FETs applications using different metal phthalocyanines and polyethyleneimines as dopants. TMDs FETs can also be used as a selective NO2 gas sensor with a polydimethylsiloxane filter and a highly sensitive photo-interfacial gated photodetector application.
10
Foss, Cameron. "Phonon Transport at Boundaries and Interfaces in Two-Dimensional Materials." 2018. https://scholarworks.umass.edu/masters_theses_2/686.
Full textAbstract:
A typical electronic or photonic device may consist of several materials each one potentially meeting at an interface or terminating with a free-surface boundary. As modern device dimensions reach deeper into the nanoscale regime, interfaces and boundaries become increasingly influential to both electrical and thermal energy transport. While a large majority of the device community focuses on the former, we focus here on the latter issue of thermal transport which is of great importance in implementing nanoscale devices as well as developing solutions for on-chip heat removal and waste heat scavenging. In this document we will discuss how modern performance enhancing techniques (strain, nanostructuring, alloying, etc.) affect thermal transport at boundaries and across interfaces through the avenue of three case studies. We use first-principles Density Functional Perturbation Theory to obtain the phonon spectrum of the materials of interest and then use the dispersion data as input to a phonon Boltzmann Transport model. First, we investigate the combined effects of strain and boundary scattering on the in-plane and cross-plane thermal conductivity of thin-film silicon and germanium. Second, we review a recently developed model for cross-dimensional (2D-3D) phonon transport and apply it to 3D-2D-3D stacked interfaces involving graphene and molybdenum disulfide 2D-layers. Third, we combine relevant models from earlier Chapters to study extrinsic effects, such as line edge roughness and substrate effects, on in-plane and through-plane thermal transport in 1H-phase transition metal dichalcogenide (TMD) alloys. Through these investigations we show that: (1) biaxial strain in Si and Ge thin-films can modulate cross-plane conductivity due to strong boundary scattering, (2) the thermal boundary conductance between 2D-3D materials can be enhanced in the presence of an encapsulating layer, and (3) the thermal conductivity of 1H-phase TMDs can be reduced by an order of magnitude through the combination of nanostructuring, alloying, and substrate effects.
Books on the topic "Two-dimensional alloys"
1
Hellman, Geoffrey, and Stewart Shapiro. Non-Euclidean Extensions. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198712749.003.0006.
Full textAbstract:
This chapter adapts the foregoing results to present two non-Euclidean theories, both in line with the (semi-)Aristotelian theme of rejecting points, as parts of regions (but working with actual infinity). The first theory is a two-dimensional hyperbolic space, that is, one that has a negative constant curvature. The second theory captures a space of constant positive curvature, a two-dimensional spherical geometry. The task here is to formulate axioms on regions which allow us to prove that (i) there are no infinitesimal regions and (ii) that there are no parallels to any given “line” through any “point” not on the given “line”.
2
Paelinck, Bernard, Aleksandar Lazarević, and Pedro Gutierrez Fajardo. Pericardial disease. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198726012.003.0049.
Full textAbstract:
Echocardiography is the cornerstone for the diagnosis of pericardial disease. It is a portable technique allowing morphological and functional multimodality (M-mode, two-dimensional, Doppler, and tissue Doppler) imaging of pericardial disease. In addition, echocardiography is essential for differential diagnosis (pericardial effusion vs pleural effusion, constrictive pericarditis vs restrictive cardiomyopathy) and allows bedside guiding of pericardiocentesis. This chapter describes normal pericardial anatomy and reviews echocardiographic features of different pericardial diseases and their pathophysiology, including pericarditis, pericardial effusion, constrictive pericarditis, pericardial cyst, and congenital absence of pericardium.
3
Monaghan, M., and S. Adhya. Three dimensional echocardiography. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199599639.003.0003.
Full textAbstract:
Three-dimensional (3D) echocardiography allows the real-time acquisition of volumes containing entire cardiac structures. The analysis of 3D volumes does not require any assumptions as to the shape of structures.3D echocardiography is more accurate than two-dimensional (2D) in the assessment of left ventricular (LV) volumes, mass, and function, and is comparable to cardiac magnetic resonance imaging. This makes it an ideal modality for measuring LV function particularly when this will determine significant interventions such as implanting of cardioverter/defibrillators, biventricular pacing, and the commencement and continuation of cancer chemotherapy. 3D echocardiography makes it easy to visualize valves and define pathological mechanisms. 3D assessment of dyssynchrony, myocardial strain, and stress imaging are attractive.However, 3D echocardiography is limited by the need for specialist software and lower spatial and temporal resolution when compared to 2D echocardiography.
4
Tribouilloy, Christophe, Patrizio Lancellotti, Ferande Peters, José Juan Gómez de Diego, and Luc A. Pierard. Heart valve disease (aortic valve disease): aortic regurgitation. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198726012.003.0033.
Full textAbstract:
Echocardiography is the cornerstone examination for the assessment of aortic regurgitation (AR): it provides reliable evaluation of the aortic valve and allows diagnosis and identification of the mechanism of regurgitation. The specific aetiology of the disease can be identified in the majority of cases. A combination of quantitative and quantitative Doppler and two-dimensional (2D) echocardiographic parameters allows the evaluation of the severity of AR and determination of the haemodynamic and left ventricular function repercussions. Echocardiography allows the detection of associated lesions of the aortic root or other valves. In symptomatic patients, echocardiography is essential to confirm the severity of AR. In asymptomatic patients with moderate or severe AR, echocardiography is essential for regular follow-up, by providing precise and reproducible measurements of LV dimensions and function, and for identifying patients who should be considered for elective surgical intervention. In most cases, transthoracic echocardiography (TTE) provides all of the necessary information and transoesophageal echocardiography in usually not required. Real-time three-dimensional (3D) TTE can be complementary to 2D echocardiography for the assessment of the mechanism and quantification of AR by increasing the level of confidence, especially when 2D echocardiographic data are inconclusive or discordant with clinical findings. Tissue Doppler imaging and especially the speckle tracking method are promising approaches to detect early LV dysfunction in patients with asymptomatic severe AR. Echocardiography is therefore the key examination for the assessment of AR and at the centre of the strategic discussion concerning the indications and timing of surgery.
5
Voigt, Jens-Uwe. Quantification of left ventricular function and synchrony using tissue Doppler, strain imaging, and speckle tracking. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199599639.003.0006.
Full textAbstract:
Modern echocardiographic systems allow the quantitative and qualitative assessment of regional myocardial function by measuring velocity, motion, deformation, and other parameters of myocardial function.Both colour Doppler (CD) and spectral Doppler modes provide one-dimensional estimates of velocity. From CD data only, further parameters can be derived. Tracking techniques have recently been introduced which provide all parameters two-dimensionally, but at the cost of lower temporal resolution.Several clinical applications have been proposed, including regional and global systolic function assessment, evaluation of diastolic cardiac properties, and assessment of ventricular dyssynchrony.This chapter provides an introduction to the method of Doppler- and tracking-based function assessment and provides a basis for understanding its different clinical applications.
6
Temperley, David. Emotion and Tension. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190653774.003.0007.
Full textAbstract:
Following much other research on musical emotion, this chapter assumes a two-dimensional representation, with one dimension representing valence (positive/negative) and the other representing energy/activity. It is argued that the valence dimension in rock is conveyed primarily by the location of a song’s scale (relative to the tonic) on the “line of fifths”; this captures the well-known major/minor contrast but also allows finer distinctions. The energy dimension is conveyed by a variety of musical parameters including loudness, register, tempo, rhythmic density, and timbral brightness. The chapter also posits a third dimension, complexity, which is taken to be represented experientially by tension; increased tension is caused by unexpected events and by an increase in event density. It has been hypothesized that a moderate level of complexity is optimal for aesthetic enjoyment; this may in part account for the appeal of certain rhythmic patterns, a phenomenon known as “groove.”
7
Levin, Frank S. Quantum Tunneling. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198808275.003.0014.
Full textAbstract:
Quantum tunneling, wherein a quanject has a non-zero probability of tunneling into and then exiting a barrier of finite width and height, is the subject of Chapter 13. The description for the one-dimensional case is extended to the barrier being inverted, which forms an attractive potential well. The first application of this analysis is to the emission of alpha particles from the decay of radioactive nuclei, where the alpha-nucleus attraction is modeled by a potential well and the barrier is the repulsive Coulomb potential. Excellent results are obtained. Ditto for the similar analysis of proton burning in stars and yet a different analysis that explains tunneling through a Josephson junction, the connector between two superconductors. The final application is to the scanning tunneling microscope, a device that allows the microscopic surfaces of solids to be mapped via electrons from the surface molecules tunneling into the tip of the STM probe.
8
Dalton, Russell J. The Evolution of Political Competition. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198830986.003.0001.
Full textAbstract:
This chapter describes how societal changes over the past several decades have reshaped the social and political interests of democratic citizens. Publics and parties have traditionally focused on the economic cleavage as a basis of electoral politics. The processes of social modernization have produced a second cultural cleavage based on environmentalism, gender equality, immigration, and identity politics. New social movements advocating these issues have stimulated a conservative backlash. This cultural cleavage now exerts influence equal to economics in shaping citizens’ policy demands. A two-dimensional space for political competition has gradually evolved to represent these new political interests, producing new parties on the far left and far right. Longitudinal data from the European Election Studies allow us to track these changes in both citizen and elite opinions from the 1970s to 2014.
9
Lancellotti, Patrizio, Julien Magne, Kim O’Connor, and Luc A. Pierard. Mitral valve disease. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199599639.003.0015.
Full textAbstract:
Native mitral valve disease is the second valvular heart disease after aortic valve disease. For the last few decades, two-dimensional Doppler echocardiography was the cornerstone technique for evaluating patients with mitral valve disease. Besides aetiological information, echocardiography allows the description of valve anatomy, the assessment of disease severity, and the description of the associated lesions.This chapter will address the echocardiographic evaluation of mitral regurgitation (MR) and mitral stenosis (MS).In MR, the following findings should be assessed: 1. Aetiology. 2. Type and extent of anatomical lesions and mechanisms of regurgitation. 3. The possibility of mitral valve repair. 4. Quantification of MR severity. 5. Quantification of MR repercussions.In MS, the following findings should be assessed: 1. Aetiology. 2. Type and extent of anatomical lesions. 3. Quantification of MS severity. 4. Quantification of MS repercussions. 5. Wilkins or Cormier scores for the possibility of percutaneous mitral commissuroplasty.Management of patients with mitral valve disease is currently based on symptoms and on echocardiographic evaluation at rest. Therefore, knowing how to assess the severity of valve diseases as well as the pitfalls and the limitations of each echocardiographic method is of primary importance.
10
Glazov, M. M. Electron & Nuclear Spin Dynamics in Semiconductor Nanostructures. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198807308.001.0001.
Full textAbstract:
In recent years, the physics community has experienced a revival of interest in spin effects in solid state systems. On one hand, solid state systems, particularly semicon- ductors and semiconductor nanosystems, allow one to perform benchtop studies of quantum and relativistic phenomena. On the other hand, interest is supported by the prospects of realizing spin-based electronics where the electron or nuclear spins can play a role of quantum or classical information carriers. This book aims at rather detailed presentation of multifaceted physics of interacting electron and nuclear spins in semiconductors and, particularly, in semiconductor-based low-dimensional structures. The hyperfine interaction of the charge carrier and nuclear spins increases in nanosystems compared with bulk materials due to localization of electrons and holes and results in the spin exchange between these two systems. It gives rise to beautiful and complex physics occurring in the manybody and nonlinear system of electrons and nuclei in semiconductor nanosystems. As a result, an understanding of the intertwined spin systems of electrons and nuclei is crucial for in-depth studying and control of spin phenomena in semiconductors. The book addresses a number of the most prominent effects taking place in semiconductor nanosystems including hyperfine interaction, nuclear magnetic resonance, dynamical nuclear polarization, spin-Faraday and -Kerr effects, processes of electron spin decoherence and relaxation, effects of electron spin precession mode-locking and frequency focusing, as well as fluctuations of electron and nuclear spins.
Book chapters on the topic "Two-dimensional alloys"
1
Montoya, F., and J. M. Dubois. "Computer Simulation of Glass Formation in two Dimensional Networks." In Ordering and Disordering in Alloys, 356–63. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2886-5_37.
Full text
2
Nikolic, Zoran S., and Masahiro Yoshimura. "Two-Dimensional Heat Transfer Model for Rapid Solidification of Ceramic Alloys." In Innovation in Ceramic Science and Engineering, 13–16. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-454-5.13.
Full text
3
Xia, Nan, Lan-Feng Yuan, and Jinlong Yang. "Transition between direct gap and indirect gap in two dimensional hydrogenated honeycomb $$\mathrm{Si}_{x}\mathrm{Ge}_{1-x}$$ alloys." In Highlights in Theoretical Chemistry, 7–11. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-47845-5_2.
Full text
4
Kodjamanova, P., H. Fietzek, Maria Juez-Lorenzo, Vladislav Kolarik, and Heike Hattendorf. "In Situ Study of Real Structure Effects on the Initial Oxidation of FeCrAl Alloys by Two-Dimensional High Temperature X-Ray Diffraction." In High-Temperature Oxidation and Corrosion 2005, 69–76. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-409-x.69.
Full text
5
Tsukanov, Alexey A., and Olga Vasiljeva. "Nanomaterials Interaction with Cell Membranes: Computer Simulation Studies." In Springer Tracts in Mechanical Engineering, 189–210. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-60124-9_9.
Full textAbstract:
AbstractThis chapter provides a brief review of computer simulation studies on the interaction of nanomaterialswith biomembranes. The interest in this area is governed by the variety of possible biomedical applications of nanoparticles and nanomaterials as well as by the importance of understanding their possible cytotoxicity. Molecular dynamics is a flexible and versatile computer simulation tool, which allows us to research the molecular level mechanisms of nanomaterials interaction with cell or bacterial membrane, predicting in silico their behavior and estimating physicochemical properties. In particular, based on the molecular dynamics simulations, a bio-action mechanism of two-dimensional aluminum hydroxide nanostructures, termed aloohene, was discovered by the research team led by Professor S. G. Psakhie, accounting for its anticancer and antimicrobial properties. Here we review three groups of nanomaterials (NMs) based on their structure: nanoparticles (globular, non-elongated), (quasi)one-dimensional NMs (nanotube, nanofiber, nanorod) and two-dimensional NMs (nanosheet, nanolayer, nanocoated substrate). Analysis of the available in silico studies, thus can enable us a better understanding of how the geometry and surface properties of NMs govern the mechanisms of their interaction with cell or bacterial membranes.
6
Righi, Riccardo. "Information Flow Simulations in Multi-dimensional and Dynamic Systems." In Communications in Computer and Information Science, 233–48. Cham: Springer Nature Switzerland, 2022. http://dx.doi.org/10.1007/978-3-031-23929-8_22.
Full textAbstract:
AbstractThe relevance of nodes with respect to the position they have in a network is often investigated with centrality measures. In particular, in cases where it is specifically meaningful to consider nodes’ ability to cumulate and convey information, like in economic systems, betweenness centrality is one of the most pertinent options because of its underlying concept. However, this statistic presents two limitations. First, as it relies on the computation of shortest paths, it is grounded on a binary topological evaluation: every time a node is not located in the shortest path between two other nodes, it gains no score at all in its centrality (even if it is located on a path just one step longer). Second, betweenness centrality does not allow the direct analysis of multi-dimensional and dynamic networks: it has to be computed one dimension and one instant at a time, and this causes problems of comparability in case of weighted connections. The scope and the originality of this work is to design a network model that makes it possible to solve these issues. The proposed Dynamic Multi-Layer Network (DMLN) allows the structural representation of the multi-dimensional and dynamic properties of nodes’ interactions. Then, this allows the computation of a metric that, based on Infomap random walks, assesses the level of information cumulated and conveyed by nodes in any moment and in any dimension of interaction. Importantly, this is performed without relying on a binary evaluation, and by jointly taking into account what occurred in all the dimensions and during the entire period, in which the system is observed. We present and discuss an implementation based on ICT worldwide trade of goods and services in the period 2004–2014.
7
Hammel, E. C., M. S. Shohag, D. O. Olawale, O. I. Okoli, and V. A. Ravi. "Pressurless Infiltration of Al2 O3 Preform Containing Aligned Two-Dimensional Channels with Al-Mg-Si Alloy." In Mechanical Properties and Performance of Engineering Ceramics and Composites XI, 207–15. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119320104.ch18.
Full text
8
Hetmaniok, Edyta, Damian Słota, and Adam Zielonka. "Parallel Procedure Based on the Swarm Intelligence for Solving the Two-Dimensional Inverse Problem of Binary Alloy Solidification." In Parallel Processing and Applied Mathematics, 287–97. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-32152-3_27.
Full text
9
Elrawashdeh, Zeina, Philippe Revel, Christine Prelle, and Frédéric Lamarque. "High Precision Fabrication of an Innovative Fiber-Optic Displacement Sensor." In Lecture Notes in Mechanical Engineering, 48–55. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-18326-3_5.
Full textAbstract:
AbstractThis study presents the high precision fabrication technique, employed to manufacture a 3D conical grating, used as the reflector element, for a fiber-optic displacement sensor. To get high performance in terms of the surface quality, as well as a dimensional precision, the surface of the reflector must be a polished-mirror surface. To do so, a high precision turning machine along with aluminum alloy were the technical choices made. Two prototypes with different geometric dimensions, have been fabricated using the same machining strategy. Single crystal diamond tool was chosen, to obtain high surface roughness. The followed machining procedure was divided into two main parts; the first part achieves several cuts, to get the desired dimensions, and the last cut is deduced to get the desired nanometric roughness. Good results have been obtained, which validates the followed machining procedure.
10
Fermont, L., B. deGeeter, M. C. Aubry, J. Kachaner, and D. Sidi. "A Close Collaboration Between Obstetricians and Pediatric Cardiologists Allows Antenatal Detection of Severe Cardiac Malformations by Two-Dimensional Echocardiography." In Pediatric Cardiology, 34–37. New York, NY: Springer New York, 1986. http://dx.doi.org/10.1007/978-1-4613-8598-1_8.
Full textConference papers on the topic "Two-dimensional alloys"
1
Léonard, François. "Optoelectronics in two-dimensional semiconductor alloys (Presentation Recording)." In SPIE Nanoscience + Engineering, edited by Nobuhiko P. Kobayashi, A. Alec Talin, M. Saif Islam, and Albert V. Davydov. SPIE, 2015. http://dx.doi.org/10.1117/12.2190303.
Full text
2
Enders, A., J. Honolka, K. Kuhnke, K. Fauth, G. Schuetz, V. Sessi, T. Lee, and K. Kern. "Hard ferromagnetism in two-dimensional FePt surface alloys." In INTERMAG 2006 - IEEE International Magnetics Conference. IEEE, 2006. http://dx.doi.org/10.1109/intmag.2006.375665.
Full text
3
Mizuno, T., Y. Nagamine, Y. Omata, M. Yokoyama, T. Aoki, and T. Sameshima. "Novel Band Structure Modulations in Two/Three-Dimensional Silicon Carbon Alloys." In 2016 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 2016. http://dx.doi.org/10.7567/ssdm.2016.o-5-03.
Full text
4
Wang, Wei, Shi Yan, Gangbing Song, and Haichang Gu. "Derivation and simulation of an improved two-dimensional constitutive law for shape memory alloys." In The 14th International Symposium on: Smart Structures and Materials & Nondestructive Evaluation and Health Monitoring, edited by Marcelo J. Dapino. SPIE, 2007. http://dx.doi.org/10.1117/12.714709.
Full text
5
Jalil, Osama, Shahzad Ahmad, Asif Bilal, Usman Younis, Xinke Liu, Kah Wee Ang, and Stavros Iezekiel. "First-principles method based electronic transport properties of two-dimensional SnSe2(1-x)X2x alloys." In Advances in Ultrafast Condensed Phase Physics II, edited by Vladislav Yakovlev, Stefan Haacke, and Sangeeta Sharma. SPIE, 2020. http://dx.doi.org/10.1117/12.2555314.
Full text
6
Brown, Tim M., Jacob Brouwer, G. Scott Samuelsen, Franklin H. Holcomb, and Joel King. "Two-Dimensional Dynamic Simulation of Hydrogen Storage in Metal Hydride Tanks." In ASME 2006 4th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2006. http://dx.doi.org/10.1115/fuelcell2006-97140.
Full textAbstract:
As proton exchange membrane fuel cell technology advances, the need for hydrogen storage intensifies. Metal hydride alloys offer one potential solution. However, for metal hydride tanks to become a viable hydrogen storage option, the dynamic performance of different tank geometries and configurations must be evaluated. In an effort to relate tank performance to geometry and operating conditions, a dynamic, two-dimensional, multi-nodal metal hydride tank model has been created in Matlab-Simulink®. Following the original work of Mayer, Groll, and Supper and the more recent paper from Aldas, Mat, and Kaplan, this model employs first principle heat transfer and fluid flow mechanisms together with empirically derived reaction kinetics. Energy and mass balances are solved in cylindrical polar coordinates for a cylindrically shaped tank. The model tank temperature, heat release, and storage volume have been correlated to an actual metal hydride tank for static and transient adsorption and desorption processes. The dynamic model is found to accurately predict observed hardware performance characteristics portending a capability to well simulate the dynamic performance of more complex tank geometries and configurations. As an example, a cylindrical tank filled via an internal concentric axial tube is considered.
7
Xu, Lei, Alexandros Solomou, Theocharis Baxevanis, and Dimitris C. Lagoudas. "A Three-Dimensional Constitutive Modeling for Shape Memory Alloys Considering Two-Way Shape Memory Effect and Transformation-Induced Plasticity." In AIAA Scitech 2019 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2019. http://dx.doi.org/10.2514/6.2019-1195.
Full text
8
Jacobs, Stephen F., Steve C. Johnston, A. C. Wanielista, and D. Bass. "Isothermal dimensional stability of various metals, alloys, welded joints, and composite structures." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.ws9.
Full textAbstract:
Using a laser interferometric method described elsewhere,1 we report on isothermal dimensional stability of the following materials: Invar, Super Invar, Kovar, molybdenum, TZM, elkonite, Al2O3, Si3N4, SiC, copper, fused silica (quartz), TiAlV, Kovar/Kovar welds, and composite structures of Mo/SiC, Mo/Si3N4, and Mo/Invar. Measurements were made over a two-month period with samples maintained in vacuum near 60°C. Quartz and Super Invar were used for secondary length references; copper for a secondary thermal reference. Invar was found to elongate ~1 ppm/month, molybdenum varies with manufacturer as does Kovar, Kovar/Kovar spot welds and seam welds shrank ~1 ppm/month, molybdenum composite structures shrank ~1 ppm/month, TZM, TiAlV, Si3N4, Al2O3 and SiC were all stable to ~0.1 ppm/month.
9
Chung, C., and F. Jain. "Two-dimensional modal analysis of blue-green lasers using ZnSe based p-n and metal-insulator-semiconductor (MIS) heterostructures." In Compact Blue-Green Lasers. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/cbgl.1992.the4.
Full textAbstract:
The wide energy gap II-VI compounds semiconductors, such as ZnSe, ZnS, MnSe, CdSe, and their ternary and quaternary alloys, are particularly suitable for the realization of short wavelength optoelectronic devices. These materials have been found to exhibit excellent luminescent properties as demonstrated by photoluminescent spectra [1] and the successful operation of photopumped lasers [2]. Recently, Haase et al[3] reported p-n heterojunction injection laser operating at cryogenic temperatures. Currently, several research groups are investigating p-type doping of ZnSe using MBE, MOCVD and CBE growth techniques. However, compensation at high nitrogen level (>1018 cm-3) still remains a problem[4]. While the effort in optimizing p-n heterojunctions to obtain room temperature lasers is being pursued intensely, an alternate approach is the use of MIS structures to obtain injection luminescence[5,6]. This paper discusses modal analysis of p-n double heterojunction and MIS laser heterostructures. In particular, ZnSe-ZnSSe, ZnSe-ZnCdSe structures are analyzed. Numerical computations of field intensities, confinement factors r and the threshold current densities JTH are presented. Experimental data of luminescence spectra in Au-SiO2-ZnSe MIS devices is also presented.
10
Kirsch, Kathryn L., Mst Kamru Nahar, and Mirna Urquidi-Macdonald. "Data Mining of General Corrosion of Most Commonly Used Alloys Using Kohonen Mapping." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77841.
Full textAbstract:
This study was developed to provide an optimum method for designing metal alloys. Information on general corrosion of the most commonly used alloys, namely nickel-, iron-, aluminum-, stainless steel-, copper- and carbon-based alloys, was obtained from the National Institute of Standards and Technology (NIST). Parameters such as pH, temperature, conductivity, and composition of the electrolyte used in each experiment (alloy in contact with an environment), along with alloy composition (UNS) and corrosion rates, were collected. The parameters in the collected data were the electrolyte characteristics, the alloy composition, and the general corrosion rates. The data consisted of over 4000 samples. The next task was to cluster the data by similarities of the parameters. A web-based, publicly available Kohonen mapping software was used to perform the clustering analysis; the two dimensional Kohonen map was chosen. The map is composed of a number of cells on a plane of two dimensions and each cell stores a sample prototype representing that cell. Kohonen maps have the ability to preserve the topological properties of the data; i.e. samples with similar “high corrosion rates” will cluster together in a given cell of the map, while samples with “low corrosion rates” will cluster in a different cell, far apart from the cell storing the “high corrosion rates” samples. Once the Kohonen map is trained to cluster the samples by their corrosion rates, each one of the parameters of the samples (representing the electrolyte characteristics, the alloy composition and the general corrosion rates) is drawn as a function of the (X,Y) map position of the cell where the samples were stored. In this paper, we present the results obtained with nickel alloy data for which 1369 samples (or independent experiments) were collected.
Reports on the topic "Two-dimensional alloys"
1
Lutz, Carsten. Interval-based Temporal Reasoning with General TBoxes. Aachen University of Technology, 2000. http://dx.doi.org/10.25368/2022.109.
Full textAbstract:
Aus der Motivation: Description Logics (DLs) are a family of formalisms well-suited for the representation of and reasoning about knowledge. Whereas most Description Logics represent only static aspects of the application domain, recent research resulted in the exploration of various Description Logics that allow to, additionally, represent temporal information, see [4] for an overview. The approaches to integrate time differ in at least two important aspects: First, the basic temporal entity may be a time point or a time interval. Second, the temporal structure may be part of the semantics (yielding a multi-dimensional semantics) or it may be integrated as a so-called concrete domain. Examples for multi-dimensional point-based logics can be find in, e.g., [21;29], while multi-dimensional interval-based logics are used in, e.g., [23;2]. The concrete domain approach needs some more explanation. Concrete domains have been proposed by Baader and Hanschke as an extension of Description Logics that allows reasoning about 'concrete qualities' of the entities of the application domain such as sizes, length, or weights of real-worlds objects [5]. Description Logics with concrete domains do usually not use a fixed concrete domain; instead the concrete domain can be thought of as a parameter to the logic. As was first described in [16], if a 'temporal' concrete domain is employed, then concrete domains may be point-based, interval-based, or both.
2
Manulis, Shulamit, Christine D. Smart, Isaac Barash, Guido Sessa, and Harvey C. Hoch. Molecular Interactions of Clavibacter michiganensis subsp. michiganensis with Tomato. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7697113.bard.
Full textAbstract:
Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial wilt and canker of tomato, is the most destructive bacterial disease of tomato causing substantial economic losses in Israel, the U.S.A. and worldwide. The molecular strategies that allow Cmm, a Gram-positive bacterium, to develop a successful infection in tomato plants are largely unknown. The goal of the project was to elucidate the molecular interactions between Cmmand tomato. The first objective was to analyze gene expression profiles of susceptible tomato plants infected with pathogenic and endophytic Cmmstrains. Microarray analysis identified 122 genes that were differentially expressed during early stages of infection. Cmm activated typical basal defense responses in the host including induction of defense-related genes, production of scavenging of free oxygen radicals, enhanced protein turnover and hormone synthesis. Proteomic investigation of the Cmm-tomato interaction was performed with Multi-Dimensional Protein Identification Technology (MudPIT) and mass spectroscopy. A wide range of enzymes secreted by Cmm382, including cell-wall degrading enzymes and a large group of serine proteases from different families were identified in the xylem sap of infected tomato. Based on proteomic results, the expression pattern of selected bacterial virulence genes and plant defense genes were examined by qRT-PCR. Expression of the plasmid-borne cellulase (celA), serine protease (pat-1) and serine proteases residing on the chp/tomA pathogenicity island (chpCandppaA), were significantly induced within 96 hr after inoculation. Transcription of chromosomal genes involved in cell wall degradation (i.e., pelA1, celB, xysA and xysB) was also induced in early infection stages. The second objective was to identify by VIGS technology host genes affecting Cmm multiplication and appearance of disease symptoms in plant. VIGS screening showed that out of 160 tomato genes, which could be involved in defense-related signaling, suppression of 14 genes led to increase host susceptibility. Noteworthy are the genes Snakin-2 (inhibitor of Cmm growth) and extensin-like protein (ELP) involved in cell wall fortification. To further test the significance of Snakin -2 and ELP in resistance towards Cmm, transgenic tomato plants over-expressing the two genes were generated. These plants showed partial resistance to Cmm resulting in a significant delay of the wilt symptoms and reduction in size of canker lesion compared to control. Furthermore, colonization of the transgenic plants was significantly lower. The third objective was to assess the involvement of ethylene (ET), jasmonate (JA) and salicylic acid (SA) in Cmm infection. Microarray and proteomic studies showed the induction of enzymes involved in ET and JA biosynthesis. Cmm promoted ET production 8 days after inoculation and SIACO, a key enzyme of ET biosynthesis, was upregulated. Inoculation of the tomato mutants Never ripe (Nr) impaired in ET perception and transgenic plants with reduced ET synthesis significantly delayed wilt symptoms as compared to the wild-type plants. The retarded wilting in Nr plants was shown to be a specific effect of ET insensitivity and was not due to altered expression of defense related genes, reduced bacterial population or decrease in ethylene biosynthesis . In contrast, infection of various tomato mutants impaired in JA biosynthesis (e.g., def1, acx1) and JA insensitive mutant (jai1) yielded unequivocal results. The fourth objective was to determine the role of cell wall degrading enzymes produced by Cmm in xylem colonization and symptoms development. A significance increase (2 to 7 fold) in expression of cellulases (CelA, CelB), pectate lyases (PelA1, PelA2), polygalacturonase and xylanases (XylA, XylB) was detected by qRT-PCR and by proteomic analysis of the xylem sap. However, with the exception of CelA, whose inactivation led to reduced wilt symptoms, inactivation of any of the other cell wall degrading enzymes did not lead to reduced virulence. Results achieved emphasized the complexity involved in Cmm-tomato interactions. Nevertheless they provide the basis for additional research which will unravel the mechanism of Cmm pathogenicity and formulating disease control measures.
3
SIMPLIFIED MODELLING OF NOVEL NON-WELDED JOINTS FOR MODULAR STEEL BUILDINGS. The Hong Kong Institute of Steel Construction, December 2021. http://dx.doi.org/10.18057/ijasc.2021.17.4.10.
Full textAbstract:
Prefabricated modular steel (PFMS) construction is a more efficient and safe method of constructing a high-quality building with less waste material and labour dependency than traditional steel construction. It is indeed critical to have a precise and valuable intermodular joining system that allows for efficient load transfer, safe handling, and optimal use of modular units' strength. Thus, the purpose of this study was to develop joints using tension bolts and solid tenons welded into the gusset plate (GP). These joints ensured rigid and secure connectivity in both horizontal and vertical directions for the modular units. Using the three-dimensional (3D) finite element (FE) analysis software ABAQUS, the study investigated the nonlinear lateral structural performance of the joint and two-storey modular steel building (MSB). The solid element FE models of joints were then simplified by introducing connectors and beam elements to enhance computational efficiency. Numerous parameters indicated that column tenons were important in determining the joint's structural performance. Moreover, with a standard deviation (SD) of 0.025, the developed connectors and beam element models accurately predicted the structural behaviour of the joints. As a result of their simplification, these joints demonstrated effective load distribution, seismic performance, and ductility while reducing computational time, effort, and complexity. The validity of the FE analysis was then determined by comparing the results to the thirteen joint bending tests performed in the reference.