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Unexpected Twinning and Phase-Transition of the Indentation Standards, Their Transition Energies, and Scientific Dichotomy
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作者 Gerd Kaupp 《Journal of Applied Mathematics and Physics》 2024年第6期2119-2159,共41页
The general use of aluminium as an indentation standard for the iteration of contact heights for the determination of ISO-14577 hardness and elastic modulus is challenged because of as yet not appreciated phase-change... The general use of aluminium as an indentation standard for the iteration of contact heights for the determination of ISO-14577 hardness and elastic modulus is challenged because of as yet not appreciated phase-changes in the physical force-depth standard curve that seemed to be secured by claims from 1992. The physical and mathematical analyses with closed formulas avoid the still world-wide standardized energy-law violation by not reserving 33.33% (h2 belief) (or 20% h3/2 physical law) of the loading force and thus energy for all not depth producing events but using 100% for the depth formation is a severe violation of the energy law. The not depth producing part of the indentation work cannot be done with zero energy! Both twinning and structural phase-transition onsets and normalized phase-transition energies are now calculated without iterations but with physically correct closed arithmetic equations. These are reported for Berkovich and cubecorner indentations, including their comparison on geometric grounds and an indentation standard without mechanical twinning is proposed. Characteristic data are reported. This is the first detection of the indentation twinning of aluminium at room temperature and the mechanical twinning of fused quartz is also new. Their disqualification as indentation standards is established. Also, the again found higher load phase-transitions disqualify aluminium and fused quartz as ISO-ASTM 14577 (International Standardization Organization and American Society for Testing and Materials) standards for the contact depth “hc” iterations. The incorrect and still world-wide used black-box values for H- and Er-values (the latter are still falsely called “Young’s moduli” even though they are not directional) and all mechanical properties that depend on them. They lack relation to bulk moduli from compression experiments. Experimentally obtained and so published force vs depth parabolas always follow the linear FN = kh3/2 + Fa equation, where Fa is the axis-cut before and after the phase-transition branches (never “h2” as falsely enforced and used for H, Er and giving incorrectly calculated parameters). The regression slopes k are the precise physical hardness values, which for the first time allow for precise calculation of the mechanical qualities by indentation in relation to the geometry of the indenter tip. Exactly 20% of the applied force and thus energy is not available for the indentation depth. Only these scientific k-values must be used for AI-advises at the expense of falsely iterated indentation hardness H-values. Any incorrect H-ISO-ASTM and also the iterated Er-ISO-ASTM modulus values of technical materials in artificial intelligence will be a disaster for the daily safety. The AI must be told that these are unscientific and must therefore be replaced by physical data. Iterated data (3 and 8 free parameters!) cannot be transformed into physical data. One has to start with real experimental loading curves and an absolute ZerodurR standard that must be calibrated with standard force and standard length to create absolute indentation results. . 展开更多
关键词 Aluminium Fused Quartz Copper TWINNING Structural phase-transitions Undue Indentation Standards Data Manipulation ZerodurR Absolute Hardness
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Physical Nanoindentation: From Penetration Resistance to Phase-Transition Energies 被引量:3
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作者 Gerd Kaupp 《Advances in Materials Physics and Chemistry》 2019年第6期103-122,共20页
-The ISO standard 14577 is challenged for its violation of the energy law, its wrong relation of normal force FN with impression depth h, and for its iterative treatments. The solution of this dilemma is the use of sa... -The ISO standard 14577 is challenged for its violation of the energy law, its wrong relation of normal force FN with impression depth h, and for its iterative treatments. The solution of this dilemma is the use of sacrosanct simplest calculation rules for the loading parabola (now FN = kh3/2) giving straight lines for cones, pyramids and wedges. They provide the physical penetration resistance hardness k with dimension [Nm-3/2] and allow for non-iterative calculations with closed formulas, using simple undeniable calculation rules. The physically correct FN versus h3/2 plot is universally valid. It separates out the most common surface effects and reveals gradients. It provides unmatched precision, including reliability checks of experimental data. Regression analysis of FN versus h3/2 plots reveals eventual unsteadiness kink phase-transition onset with the transition-energy. This is shown for all kinds of solid materials, including salts, silicon, organics, polymers, composites, and superalloys. Exothermic and endothermic single and consecutive multiple phase-transitions with their surface dependence are distinguished and the results compared in 5 Tables. The sharp phase-transition onsets and the transition energies provide unprecedented most important materials’ characteristics that are indispensable for safety reasons. ISO ASTM is thus urged to thoroughly revise ISO 14577 and to work out new standards for the mechanically (also thermally) stressed materials. For example, the constancy of the first phase-transition parameters must be controlled, and materials must only be admitted for maximal forces well below the first phase-transition onset. Such onset loads can now be easily calculated. The nevertheless repeated oppositions against the physical analysis of indentations rest on incredibly poor knowledge of basic mathematics, errors that are uncovered. The safety aspects caused by the present unphysical materials’ parameters are discussed. 展开更多
关键词 ENERGY Law VIOLATION ISO-14577 Challenge Calculation Rules for Indentations phase-transition ONSET and ENERGY Multiple Transitions Safety Problems
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Industrial Application of a Deep Purification Technology for Flue Gas Involving Phase-Transition Agglomeration and Dehumidification 被引量:11
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作者 Jianmin Liu Fahua Zhu Xiuyuan Ma 《Engineering》 2018年第3期416-420,共5页
A moist plume forms when the flue gas emitted from wet desulfurization equipment exits into the ambi- ent air, resulting in a waste of water resources and visual pollution. In addition, sulfur trioxide (SO3), water ... A moist plume forms when the flue gas emitted from wet desulfurization equipment exits into the ambi- ent air, resulting in a waste of water resources and visual pollution. In addition, sulfur trioxide (SO3), water with dissolved salts, and particles in the wet flue gas form secondary pollution in the surrounding atmosphere. In this study, a deep purification technology for flue gas involving phase-transition agglom- eration and dehumidification (PAD) is proposed. This deep purification technology includes two technical routes: the integrated technology of phase-transition agglomeration and a wet electrostatic precipitator (PAW); and the integrated technology of phase-transition agglomeration and a mist eliminator (PAM). Industrial applications of PAW and PAM were carried out on 630 and 1000 MW coal-fired units, respectively. The results show that the average amount of recycled water obtained from wet flue gas by means of PAD is more than 4 g.(kg.℃)-1 Decreasing the wet flue gas temperature by 1.5-5.3 ℃ allows 5%-20% of the moisture in the flue gas to be recycled; therefore, this process could effectively save water resources and significantly reduce water vapor emissions. In addition, the moist plume is effectively elim- inated. With the use of this process, the ion concentration in droplets of flue gas is decreased by more than 65%, the SO3 removal efficiency from flue gas is greater than 75%, and the removal efficiency of par- ticulate matter is 92.53%. 展开更多
关键词 Moist plume phase-transition agglomeration DEHUMIDIFICATION Dissolved salts SO3 Particulate matter
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Magnetism and phase-transitional analysis of nano-metal gadolinium
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作者 侯碧辉 刘凤艳 +1 位作者 岳明 曾宏 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第6期1018-1022,共5页
The structures,grain sizes and magnetism were analyzed and computed for three typical samples:the stock of polycrystalline metal Gd(sample 1),the bulk nanocrystalline Gd prepared by spark plasma sintering(SPS) techniq... The structures,grain sizes and magnetism were analyzed and computed for three typical samples:the stock of polycrystalline metal Gd(sample 1),the bulk nanocrystalline Gd prepared by spark plasma sintering(SPS) technique and subjected to the annealing process of 623 K for 0.5 h(sample 2) and the bulk nanocrystalline Gd prepared by the SPS technique at 573 K(sample 3).The computation results indicated that the sample 3 had the efficiency of space filling up to 99.38%.The computation results of magnetization i... 展开更多
关键词 GADOLINIUM FERROMAGNETISM ANTIFERROMAGNETISM phase-transition nanocrystal rare earths
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A Quenched Study for QCD Phase-Transition on Anisotropic Lattices
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作者 MENG Xiang-Fei CHEN Ying LIU Yu-Bin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第10期665-670,共6页
The QCD deconfinement phase transition in pure SU(3) gauge theory is studied on an anlsotropic lattice. The critical temperature is determined to be Tc ≈ 285 MeV. The relation between the deconfinement phase transi... The QCD deconfinement phase transition in pure SU(3) gauge theory is studied on an anlsotropic lattice. The critical temperature is determined to be Tc ≈ 285 MeV. The relation between the deconfinement phase transition and the breakdown of Z(3) center symmetry is also discussed. 展开更多
关键词 phase-transition critical temperature anisotropic lattice
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Finding Short-Range Parity-Time Phase-Transition Points with a Neural Network
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作者 Songju Lei Dong Bai +1 位作者 Zhongzhou Ren Mengjiao Lyu 《Chinese Physics Letters》 SCIE CAS CSCD 2021年第5期7-10,共4页
The non-Hermitian PT-symmetric system can live in either unbroken or broken PT-symmetric phase. The separation point of the unbroken and broken PT-symmetric phases is called the PT-phase-transition point.Conventionall... The non-Hermitian PT-symmetric system can live in either unbroken or broken PT-symmetric phase. The separation point of the unbroken and broken PT-symmetric phases is called the PT-phase-transition point.Conventionally, given an arbitrary non-Hermitian PT-symmetric Hamiltonian, one has to solve the corresponding Schrodinger equation explicitly in order to determine which phase it is actually in. Here, we propose to use artificial neural network(ANN) to determine the PT-phase-transition points for non-Hermitian PT-symmetric systems with short-range potentials. The numerical results given by ANN agree well with the literature, which shows the reliability of our new method. 展开更多
关键词 ANN Hamiltonian Finding Short-Range Parity-Time phase-transition Points with a Neural Network
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Capillary Phase-Transition and Self-Diffusion of Ethylene in the Slit Carbon Pores
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作者 刘涛 刘洪来 袁渭康 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第4期515-520,共6页
The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensat... The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensation and evaporation) and self-diffusion for a simple Lennard-Jones model of ethylene confined in slit carbon pores of 2.109 nm at temperatures between 141.26 K and 201.80 K. The critical point of capillary phase-transition was extrapolated by the critical power law and the law of rectilinear diameter from the capillary phase-transition data in the near critical region. The effects of temperature and fluid density on the parallel self-diffusion coefficients of ethylene molecules confined in the slit carbon pores were examined. The results showed that the parallel selfdiffusion coefficients in the capillary phase transition area strongly depended on the fluids local densities in the slit carbon pores. 展开更多
关键词 capillary phase-transition SELF-DIFFUSION
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MEMS-actuated terahertz metamaterials driven by phase-transition materials
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作者 Zhixiang Huang Weipeng Wu +5 位作者 Eric Herrmann Ke Ma Zizwe A.Chase Thomas A.Searles M.Benjamin Jungfleisch Xi Wang 《Frontiers of Optoelectronics》 EI CSCD 2024年第2期23-32,共10页
The non-ionizing and penetrative characteristics of terahertz(THz)radiation have recently led to its adoption across a variety of applications.To effectively utilize THz radiation,modulators with precise control are i... The non-ionizing and penetrative characteristics of terahertz(THz)radiation have recently led to its adoption across a variety of applications.To effectively utilize THz radiation,modulators with precise control are imperative.While most recent THz modulators manipulate the amplitude,frequency,or phase of incident THz radiation,considerably less progress has been made toward THz polarization modulation.Conventional methods for polarization control suffer from high driving voltages,restricted modulation depth,and narrow band capabilities,which hinder device performance and broader applications.Consequently,an ideal THz modulator that offers high modulation depth along with ease of processing and operation is required.In this paper,we propose and realize a THz metamaterial comprised of microelectromechanical systems(MEMS)actuated by the phase-transition material vanadium dioxide(VO_(2)).Simulation and experimental results of the three-dimensional metamaterials show that by leveraging the unique phase-transition attributes of VO_(2),our THz polarization modulator offers notable advancements over existing designs,including broad operation spectrum,high modulation depth,ease of fabrication,ease of operation condition,and continuous modulation capabilities.These enhanced features make the system a viable candidate for a range of THz applications,including telecommunications,imaging,and radar systems. 展开更多
关键词 METAMATERIALS MEMS THZ VO_(2) phase-transition material
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Dual-functional bacterial cellulose modified with phase-transitioned proteins and gold nanorods combining antifouling and photothermal bactericidal properties
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作者 Luohuizi Li Guize Li +8 位作者 Yong Wu Yuancheng Lin Yangcui Qu Yan Wu Kunyan Lu Yi Zou Hong Chen Qian Yu Yanxia Zhang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第15期14-23,共10页
Bacterial cellulose(BC)is one of the most versatile natural biopolymers with unique physical,chemical,and biological features.However,the lack of intrinsic antibacterial property of native BC limits its broad biomedic... Bacterial cellulose(BC)is one of the most versatile natural biopolymers with unique physical,chemical,and biological features.However,the lack of intrinsic antibacterial property of native BC limits its broad biomedical applications where such property is highly required to prevent contamination or infection caused by attached bacteria.In this work,we developed a simple and facile method to fabricate a dualfunctional BC membrane by physical incorporation of gold nanorods(GNRs)followed by deposition of a phase-transitioned bovine serum albumin(PTB)film.Due to the broad-spectrum antifouling property of the PTB film,the resulting membrane could prevent the adhesion and accumulation of bacteria.A few bacteria that broke through the protection of the PTB film could be eradicated under short-term irradiation of a near-infrared laser due to the excellent photothermal property of incorporated GNRs.The whole fabrication was conducted in a simple and environmentally friendly manner,avoiding complicated processes and toxic organic solvents.Moreover,because all the components were biocompatible,the resulting membrane showed negligible cytotoxicity in vitro and good histocompatibility in vivo.This work thus provided a reliable way to endow BC with antibacterial property,being beneficial for diverse biomedical applications. 展开更多
关键词 Bacterial cellulose Gold nanorods phase-transitioned proteins ANTIFOULING Antibacterial Photothermal therapy
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Opinion Spreading with Mobility on Scale-Free Networks 被引量:6
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作者 郭强 刘建国 +3 位作者 汪秉宏 周涛 陈兴文 姚玉华 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第2期773-775,共3页
A continuum opinion dynamic model is presented based on two rules. The first one considers the mobilities of the individuals, the second one supposes that the individuals update their opinions independently. The resul... A continuum opinion dynamic model is presented based on two rules. The first one considers the mobilities of the individuals, the second one supposes that the individuals update their opinions independently. The results of the model indicate that the bounded confidence εc, separating consensus and incoherent states, of a scale-free network is much smaller than the one of a lattice. If the system can reach the consensus state, the sum of all individuals' opinion change Oc(t) quickly decreases in an exponential form, while if it reaches the incoherent state finally, Oc(t) decreases slowly and has the punctuated equilibrium characteristic. 展开更多
关键词 SCIENCE BASIC RESEARCH SMALL-WORLD NETWORKS COMPLEX NETWORKS phase-transition SZNAJD MODEL DYNAMICS OPTIMIZATION ROBUSTNESS EVOLUTION
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Cellular automaton model considering headway-distance effect 被引量:4
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作者 胡守信 高坤 +1 位作者 汪秉宏 陆玉凤 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第5期1863-1868,共6页
This paper presents a cellular automaton model for single-lane traffic flow. On the basis of the Nagel-Schreckenberg (NS) model, it further considers the effect of headway-distance between two successive cars on the... This paper presents a cellular automaton model for single-lane traffic flow. On the basis of the Nagel-Schreckenberg (NS) model, it further considers the effect of headway-distance between two successive cars on the randomization of the latter one. In numerical simulations, this model shows the following characteristics. (1) With a simple structure, this model succeeds in reproducing the hysteresis effect, which is absent in the NS model. (2) Compared with the slow-tostart models, this model exhibits a local fundamental diagram which is more consistent to empirical observations. (3) This model has much higher efficiency in dissolving congestions compared with the so-called NS model with velocitydependent randomization (VDR model). (4) This model is more robust when facing traffic obstructions. It can resist much longer shock times and has much shorter relaxation times on the other hand. To summarize, compared with the existing models, this model is quite simple in structure, but has good characteristics. 展开更多
关键词 traffic flow headway-distance phase-transition fundamental diagram
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Liquid-Liquid Structure Transition in Metallic Melts: Experimental Evidence by Viscosity Measurement 被引量:3
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作者 王玉青 武玉琴 边秀房 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第7期2028-2031,共4页
Temperature dependence of viscosity for more than ten kinds of metallic melts is analysed based on viscosity measurements. An obvious turning point is observed on the Arrhenius curves. Since viscosity is one of the ph... Temperature dependence of viscosity for more than ten kinds of metallic melts is analysed based on viscosity measurements. An obvious turning point is observed on the Arrhenius curves. Since viscosity is one of the physical properties sensitive to structure, its discontinuous change with temperature reveals the possible liquidliquid structure transition in the metallic melts. Furthermore, an integrated liquid structure transition diagram of the Sn-Bi system is presented. The universality of liquid-liquid structure transition is also discussed simply. 展开更多
关键词 phase-transition HIGH-DENSITY WATER ORDER
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Finite Element Method on Shape Memory Alloy Structure and Its Applications 被引量:1
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作者 Bo Zhou Zetian Kang +1 位作者 Zhiyong Wang Shifeng Xue 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2019年第5期125-135,共11页
It is significant to numerically investigate thermo-mechanical behaviors of shape memory alloy(SMA)structures undergoing large and uneven deformation for they are used in many engineering fields to meet special requir... It is significant to numerically investigate thermo-mechanical behaviors of shape memory alloy(SMA)structures undergoing large and uneven deformation for they are used in many engineering fields to meet special requirements To solve the problems of convergence in the numerical simulation on thermo-mechanical behaviors of SMA structures by universal finite element software.This work suppose a finite element method to simulate the super-elasticity and shape memory effect in the SMA structure undergoing large and uneven deformation.Two scalars,named by phase-transition modulus and equivalent stiffness,are defined to make it easy to establish and implement the finite element method for a SMA structure.An incremental constitutive equation is developed to formulate the relationship of stress,strain and temperature in a SMA material based on phase-transition modulus and equivalent stiffness.A phase-transition modulus equation is derived to describe the relationship of phase-transition modulus,stress and temperature in a SMA material during the processes of martensitic phase transition and martensitic inverse phase transition.A finite element equation is established to express the incremental relationship of nodal displacement,external force and temperature change in a finite element discrete structure of SMA.The incremental constitutive equation,phase-transition modulus equation and finite element equation compose the supposed finite element method which simulate the thermo-mechanical behaviors of a SMA structure.Two SMA structures,which undergo large and uneven deformation,are numerically simulated by the supposed finite element method.Results of numerical simulation show that the supposed finite element method can effectively simulate the super-elasticity and shape memory effect of a SMA structure undergoing large and uneven deformation,and is suitable to act as an effective computational tool for the wide applications based on the SMA materials. 展开更多
关键词 Shape memory alloy Incremental CONSTITUTIVE EQUATION Finite element EQUATION phase-transition MODULUS APPLICATIONS
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Cluster-size dependent randomization traffic flow model 被引量:1
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作者 高坤 汪秉宏 +1 位作者 付传技 陆玉凤 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第11期3483-3493,共11页
In order to exhibit the meta-stable states, several slow-to-start rules have been investigated as modification to Nagel-Schreckenberg (NS) model. These models can reproduce some realistic phenomena which are absent ... In order to exhibit the meta-stable states, several slow-to-start rules have been investigated as modification to Nagel-Schreckenberg (NS) model. These models can reproduce some realistic phenomena which are absent in the original NS model. But in these models, the size of cluster is still not considered as a useful parameter. In real traffic, the slow-to-start motion of a standing vehicle often depends on the degree of congestion which can be measured by the clusters' size. According to this idea, we propose a cluster-size dependent slow-to-start model based on the speed- dependent slow-to-start rule (VDR) model. It gives expected results through simulations. Comparing with the VDR model, our new model has a better traffic efficiency and shows richer complex characters. 展开更多
关键词 traffic flow slow-to-start JAM phase-transition hysteresis effect
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Water Gas Shift Reaction: A Monte Carlo Simulation 被引量:1
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作者 Waqar AHMAD Akhtar HUSSAIN 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第9期2602-2605,共4页
The water gas shift (WGS) reaction is reacts with water on a catalytic surface a process of industrial importance to form CO2 and H2. We study this In this reaction carbon monoxide reaction with thermal (Langmuir- ... The water gas shift (WGS) reaction is reacts with water on a catalytic surface a process of industrial importance to form CO2 and H2. We study this In this reaction carbon monoxide reaction with thermal (Langmuir- Hinshelwood) and non-thermal (precursor and Eley-Rideal) reaction mechanisms using the techniques of Monte Carlo computer simulation. The details of surface coverages and production rates are given as a function of CO partial pressure. The diffusion of species on the surface as well as their desorption from the surface is also introduced to include temperature effects. The phase diagrams of the system have been drawn to observe the behaviour of reacting species on the surface. The study reveals that the production rates are higher for non-thermal precursor mechanism and are in agreement with the experimental finding. 展开更多
关键词 KINETIC phase-transitionS SURFACE-REACTION MODEL HETEROGENEOUS CATALYSIS NITROGEN CHEMISORPTION MECHANISM TUNGSTEN DIAGRAM FACE
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Electron Transport Property of CdTe under High Pressure and Moderate Temperature by In-Situ Resistivity Measurement in Diamond Anvil Cell 被引量:1
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作者 贺春元 高春晓 +5 位作者 李明 郝爱民 黄晓伟 张东梅 于翠玲 王月 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第4期1070-1072,共3页
In situ resistivity measurement has been performed to investigate the electron transport property of powered CdTe under high pressure and moderate temperature in a designed diamond anvil cell. Several abnormal resisti... In situ resistivity measurement has been performed to investigate the electron transport property of powered CdTe under high pressure and moderate temperature in a designed diamond anvil cell. Several abnormal resistivity changes can be found at room temperature when the pressure increases from ambient to 33 GPa. The abnormal resistivity changes at about 3.8 GPa and 10 GPa are caused by the structural phase transitions to the rock-salt phase and to the Cmcm phase, respectively. The other abnormal resistivity changes at about 6.5 GPa, 15.5 GPa, 22.2 GPa and about 30 GPa never observed before are due to the electronic phase transitions of CdTe. The origin of the abnormal change occurred at about 6.5 GPa is discussed. The temperature dependence of the resistivity of CdTe shows its semiconducting behaviour at least before 11.3 GPa. 展开更多
关键词 phase-transitionS III-V GPA
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Fluctuation of the Download Network 被引量:1
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作者 韩定定 刘锦高 马余刚 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第2期765-768,共4页
The scaling behaviour of fluctuation for a download network we investigated a few years ago based upon Zhang's Econophysics web page is presented. A power law scaling, namely σ~〈f〉^α exists between the dispersio... The scaling behaviour of fluctuation for a download network we investigated a few years ago based upon Zhang's Econophysics web page is presented. A power law scaling, namely σ~〈f〉^α exists between the dispersion a and average flux 〈f〉 of the download rates. The fluctuation exponent α is neither 1/2 nor 1, which were claimed as two universal fluctuation classes in previous publication, while it varies from 1/2 to 1 with the time window in which the download data are accumulated. The crossover behaviour of fluctuation exponents can be qualitatively understood by the external driving fluctuation model for a small-size system or a network traffic model which suggests congestion as the origin. 展开更多
关键词 phase-transition ION COLLISIONS
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Real and Fitted Spherical Indentations 被引量:2
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作者 Gerd Kaupp 《Advances in Materials Physics and Chemistry》 2020年第10期207-229,共23页
Spherical indentations that rely on original date are analyzed with the physically correct mathematical formula and its integration that take into account the radius over depth changes upon penetration. Linear plots, ... Spherical indentations that rely on original date are analyzed with the physically correct mathematical formula and its integration that take into account the radius over depth changes upon penetration. Linear plots, phase-transition onsets, energies, and pressures are algebraically obtained for germanium, zinc-oxide and gallium-nitride. There are low pressure phase-transitions that correspond to, or are not resolved by hydrostatic anvil onset pressures. This enables the attribution of polymorph structures, by comparing with known structures from pulsed laser deposition or molecular beam epitaxy and twinning. The spherical indentation is the easiest way for the synthesis and further characterization of polymorphs, now available in pure form under diamond calotte and in contact with their corresponding less dense polymorph. The unprecedented results and new possibilities require loading curves from experimental data. These are now easily distinguished from data that are “fitted” to make them concur with widely used unphysical Johnson’s formula for spheres (“<span style="white-space:nowrap;"><em>P</em> = (4/3)<em>h</em><sup>3/2</sup><em>R</em><sup>1/2</sup><em>E</em><sup><span style="white-space:nowrap;">&#8727;</span></sup></span>”) not taking care of the <em>R/h</em> variation. Its challenge is indispensable, because its use involves “fitting equations” for making the data concur. These faked reports (no “experimental” data) provide dangerous false moduli and theories. The fitted spherical indentation reports with radii ranging from 4 to 250 μm are identified for PDMS, GaAs, Al, Si, SiC, MgO, and Steel. The detailed analysis reveals characteristic features. 展开更多
关键词 Spherical Indentations Correct Formula phase-transition Onset Pressure False Johnson Formula Detection of Data Fittings
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Undue Hardness/Modulus Ratio Claims instead of Physical Penetration Resistance and Applications with Mollusk Shells 被引量:1
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作者 Gerd Kaupp 《Advances in Materials Physics and Chemistry》 2021年第2期45-57,共13页
The Nanoindentation is a precise technique for the elucidation of mechanical properties. But such elucidation requires physically based interpretation of the loading curves that is widely still not practiced. The use ... The Nanoindentation is a precise technique for the elucidation of mechanical properties. But such elucidation requires physically based interpretation of the loading curves that is widely still not practiced. The use of indentation hardness <em>H</em> and indentation modulus <em>E<sub>r</sub></em> is unphysical and cannot detect the most important phase-transitions under load that very often occur. The claim that <em>H </em>versus<em> E </em>plots relate linearly for all different materials is neither empirically found nor correctly deduced. It is most dangerous by producing incorrect materials properties and misleading. The use of <em>H/E</em> (that is also called “elasticity index”) in complicated formulas for brittle parameter, yield strength, toughness, and so-called “true hardness” is also in error. The use of<em> H/E </em>cannot reveal the true qualities of materials without considering phase-transitions under load that require the correct exponent 3/2 on <em>h</em> for the loading curves (instead of disproved 2). This is exemplified with the physical data of different mollusk shells that experience phase-transitions, a new bionics model, and different contributions for their strengthening. The data are compared to the ones of aragonite and calcite and vaterite. 展开更多
关键词 Nanoindentation H/E Ratio Challenge phase-transitionS Penetration Resistance Mollusk Shells ARAGONITE Calcite Bionics
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Transition Temperature of Two-Degenerate-Flavour QCD in the Chiral Limit
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作者 吴良凯 罗向前 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第10期2769-2772,共4页
We present the results for the transition temperature of quantum chromodynamics (QCD) with two degenerate flavours (Nf = 2) of Wilson quarks. On lattice 8^3 × 4 with 4 representing the temporal extent, by usi... We present the results for the transition temperature of quantum chromodynamics (QCD) with two degenerate flavours (Nf = 2) of Wilson quarks. On lattice 8^3 × 4 with 4 representing the temporal extent, by using the Ferrenberg-Swendsen reweighting method, we determine the critical β = 6/g^2 where the transition occurs, g is the coupling constant. On lattice 8^2 × 20 × 4, by using the axial vector Ward-Takahashi identity, we calculate the current quark mass amq, a is the lattice spacing. Assuming the O(4) scaling, the critical β in the chiral limit is determined. We calculate the p meson mass amp at zero temperature on lattice 8^3 × 20. By using the experimental p meson mass to set the scale, we obtain 194(1) MeV for the transition temperature in the chiral limit. 展开更多
关键词 phase-transition WILSON QUARKS 2-FLAVOR QCD LATTICE THERMODYNAMICS CHROMODYNAMICS SYMMETRY
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