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Numerical Simulation for Two-Phase Water Hammer Flows in Pipe by Quasi-Two-Dimensional Model 被引量:1
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作者 Tae Uk Jang Yuebin Wu +1 位作者 Ying Xu Qiang Sun 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2016年第2期9-15,共7页
The features of a quasi-two-dimensional( quasi-2D) model for simulating two-phase water hammer flows with vaporous cavity in a pipe are investigated. The quasi-2D model with discrete vaporous cavity in the pipe is pro... The features of a quasi-two-dimensional( quasi-2D) model for simulating two-phase water hammer flows with vaporous cavity in a pipe are investigated. The quasi-2D model with discrete vaporous cavity in the pipe is proposed in this paper. This model uses the quasi-2D model for pure liquid zone and one-dimensional( 1D) discrete vapor cavity model for vaporous cavity zone. The quasi-2D model solves two-dimensional equations for both axial and radial velocities and 1D equations for both pressure head and discharge by the method of characteristics. The 1D discrete vapor cavity model is used to simulate the vaporous cavity occurred when the pressure in the local pipe is lower than the vapor pressure of the liquid. The proposed model is used to simulate two-phase water flows caused by the rapid downstream valve closure in a reservoir-pipe-valve system.The results obtained by the proposed model are compared with those by the corresponding 1D model and the experimental ones provided by the literature,respectively. The comparison shows that the maximum pressure heads simulated by the proposed model are more accurate than those by the corresponding 1D model. 展开更多
关键词 water HAMMER method of characteristics quasi -two -dimensional MODEL COLUMN separation discrete vapor cavity MODEL
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Exact analytic solutions for an elliptic hole with asymmetric collinear cracks in a one-dimensional hexagonal quasi-crystal 被引量:18
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作者 郭俊宏 刘官厅 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第7期2610-2620,共11页
Using the complex variable function method and the technique of conformal mapping, the anti-plane shear problem of an elliptic hole with asymmetric colfinear cracks in a one-dimensional hexagonal quasi-crystal is solv... Using the complex variable function method and the technique of conformal mapping, the anti-plane shear problem of an elliptic hole with asymmetric colfinear cracks in a one-dimensional hexagonal quasi-crystal is solved, and the exact analytic solutions of the stress intensity factors (SIFs) for mode Ⅲ problem are obtained. Under the limiting conditions, the present results reduce to the Griffith crack and many new results obtained as well, such as the circular hole with asymmetric collinear cracks, the elliptic hole with a straight crack, the mode T crack, the cross crack and so on. As far as the phonon field is concerned, these results, which play an important role in many practical and theoretical applications, are shown to be in good agreement with the classical results. 展开更多
关键词 one-dimensional hexagonal quasi-crystals elliptic hole with asymmetric collinear cracks stress intensity factor complex variable function method
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Phonons near Peierls Structural Transition in Quasi-One-Dimensional Organic Crystals of TTF-TCNQ 被引量:2
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作者 Silvia Andronic Anatolie Casian 《Advances in Materials Physics and Chemistry》 2016年第4期98-104,共7页
The Peierls structural transition in quasi-one-dimensional organic crystals of TTF-TCNQ is investigated in the frame of a more complete physical model. The two most important electron-phonon interaction mechanisms are... The Peierls structural transition in quasi-one-dimensional organic crystals of TTF-TCNQ is investigated in the frame of a more complete physical model. The two most important electron-phonon interaction mechanisms are taken into account simultaneously. One is similar of that of deformation potential and the other is of polaron type. For simplicity, the 2D crystal model is considered. The renormalized phonon spectrum and the phonon polarization operator are calculated in the random phase approximation for different temperatures. The effects of interchain interaction on renormalized acoustic phonons and on the Peierls critical temperature are analyzed. 展开更多
关键词 quasi-One-dimensional Organic Crystals TTF-TCNQ Peierls Transition Interchain Interaction Renormalized Phonons
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Quasi-Dimensional Modeling of a CNG Fueled HCCI Engine Combustion Using Detailed Chemical Kinetic
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作者 Younes Bakhshan Amir H. Shadaei S. Niazi 《Advances in Chemical Engineering and Science》 2011年第4期198-207,共10页
In this study, an in-house quasi dimensional code has been developed which simulates the intake, compression, combustion, expansion and exhaust strokes of a homogeneous charge compression ignition (HCCI) engine. The c... In this study, an in-house quasi dimensional code has been developed which simulates the intake, compression, combustion, expansion and exhaust strokes of a homogeneous charge compression ignition (HCCI) engine. The compressed natural gas (CNG) has been used as fuel. A detailed chemical kineticscheme constituting of 310 and 1701 elementary equations developed by [Bakhshan and al.] has been applied for combustion modeling andheat release calculations. The zero-dimensional k-ε turbulence model has been used for calculation of heat transfer. The output results are the performance and pollutants emission and combustion characteristics in HCCI engines. Parametric studies have been conducted to discussing the effects of various parameters on performance and pollutants emission of these engines. 展开更多
关键词 HCCI quasi dimensionAL Detailed CHEMICAL KINETIC CNG Simulation k-ε
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Mild Hydrothermal Synthesis,Crystal Structure and Magnetic Behavior of AgCu(IO_3)_3:a Quasi-one-dimensional S=1/2 Chain Compound
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作者 韩梅 冯守华 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2018年第1期140-144,共5页
A new complex AgCu(IO3)3 is synthesized by mild hydrothermal method and characterized by single-crystal X-ray diffraction and magnetization measurement.AgCu(IO3)3 is triclinic,space group P1,with a = 7.3081(1),b... A new complex AgCu(IO3)3 is synthesized by mild hydrothermal method and characterized by single-crystal X-ray diffraction and magnetization measurement.AgCu(IO3)3 is triclinic,space group P1,with a = 7.3081(1),b = 7.8089(1),c = 8.2447(1)A,α = 67.159(1),β = 74.982(1),γ = 80.982(1)°,and Z = 2.AgCu(IO3)3 is isostructral with Ag Pb(IO3)3.The structure of Ag Cu(IO3)3 consists of CuO6 chain columns parallel to the c axis,formed by corner-sharing Cu(1) and Cu(2) octahedra and flanked by corner-sharing IO3 groups; these CuO6 columns are cross-linked into a three-dimensional framework through I–O and Ag–O bonds.I(1),I(2) and I(3) are coordinated respectively with 3 oxygens on the same side to form trigonal pyramids confirming the presence of a stereochemically active lone pair of each I^5+ cation.In the CuO6 chain columns,Cu(1)O6 and Cu(2)O6 octahedra are tetragonally distorted with four shorter bonds in the square planes and two longer apical bonds.Cu(1)O6 octahedra were corner sharing with Cu(2)O6 octahedra with a shorter Cu(1)–O(1) bond in the square planes and a longer apical Cu(2)–O(1) bond,which forms a Cu(1)–Cu(2) magnetic chain along the c direaction.Magnetization measurement shows weak antiferromagnetic property in low temperature range.Ag Cu(IO3)3 provides a new example of a quasi-one-dimensional magnetic system. 展开更多
关键词 hydrothermal synthesis crystal structure quasi-one-dimensional magnetic system
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Broadening Thermal Energy Levels and Density States Quasi One-Dimensional Electron Gas
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作者 P. J. Baymatov A. G. Gulyamov +1 位作者 A. B. Davlatov B. B. Uzakov 《Journal of Applied Mathematics and Physics》 2016年第4期706-710,共5页
We have investigated the energy states of a one-dimensional electron gas and analyzed the temperature dependence of the density of states. It is shown that with increasing temperature due to thermal broadening of quan... We have investigated the energy states of a one-dimensional electron gas and analyzed the temperature dependence of the density of states. It is shown that with increasing temperature due to thermal broadening of quantum, levels are blurred. 展开更多
关键词 quasi One-dimensional Electron Gas Density of States Thermal Broadening
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Metal-Insulator Transition of Peierls Type in Quasi-One-Dimensional Crystals of TTT<sub>2</sub>I<sub>3</sub>
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作者 Silvia Andronic Anatolie Casian 《Advances in Materials Physics and Chemistry》 2017年第5期212-222,共11页
We investigate the metal-insulator transition in quasi-one-dimensional organic crystals of tetrathiotetracene-iodide, TTT2I3, in the 2D model. A crystal physical model is applied which takes into account two the most ... We investigate the metal-insulator transition in quasi-one-dimensional organic crystals of tetrathiotetracene-iodide, TTT2I3, in the 2D model. A crystal physical model is applied which takes into account two the most important hole-phonon interaction mechanisms. One is similar to that of deformation potential and the other is of polaron type. The scattering on defects is also considered and it is crucial for the explanation of the transition. The phonon polarization operator and the renormalized phonon spectrum are calculated in the random phase approximation for different temperatures applying the method of Green functions. We show that the transition is of Peierls type. The effect of lattice distortion on the dispersion of renormalized acoustic phonons is analyzed. 展开更多
关键词 quasi-ONE-dimensionAL Organic CRYSTALS TTT2I3 Polarization Operator Metal-Insulator TRANSITION PEIERLS TRANSITION Interchain Interaction Renormalized Phonons
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Establishment of infinite dimensional Hamiltonian system of multilayer quasi-geostrophic flow & study on its linear stability
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作者 黄思训 王宇 项杰 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第11期300-309,共10页
A multilayer flow is a stratified fluid composed of a finite number of layers with densities homogeneous within one layer but different from each other. It is an intermediate system between the single-layer barotropic... A multilayer flow is a stratified fluid composed of a finite number of layers with densities homogeneous within one layer but different from each other. It is an intermediate system between the single-layer barotropic model and the continuously stratified baroclinic model. Since this system can simulate the baroclinic effect simply, it is widely used to study the large-scale dynamic process in atmosphere and ocean. The present paper is concerned with the linear stability of the multilayer quasi-geostrophic flow, and the associated linear stability criteria are established. Firstly, the nonlinear model is turned into the form of a Hamiltonian system, and a basic flow is defined. But it cannot be an extreme point of the Hamiltonian function since the system is an infinite-dimensional one. Therefore, it is necessary to reconstruct a new Hamiltonian function so that the basic flow becomes an extreme point of it. Secondly, the linearized equations of disturbances in the multilayer quasi-geostrophic flow are derived by introducing infinitesimal disturbances superposed on the basic flows. Finally, the properties of the linearized system are discussed, and the linear stability criteria in the sense of Liapunov are derived under two different conditions with respect to certain norms. 展开更多
关键词 infinite dimensional Hamiltonian system multilayer quasi-geostrophic flow linear stability
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Periodic,quasiperiodic and chaotic discrete breathers in a parametrical driven two-dimensional discrete diatomic Klein-Gordon lattice
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作者 徐权 田强 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第6期2469-2474,共6页
We study a two-dimensional (2D) diatomic lattice of anhaxmonic oscillators with only quartic nearest-neighbor interactions, in which discrete breathers (DBs) can be explicitly constructed by an exact separation of... We study a two-dimensional (2D) diatomic lattice of anhaxmonic oscillators with only quartic nearest-neighbor interactions, in which discrete breathers (DBs) can be explicitly constructed by an exact separation of their time and space dependence. DBs can stably exist in the 2D discrete diatomic Klein-Gordon lattice with hard and soft on-site potentials. When a parametric driving term is introduced in the factor multiplying the harmonic part of the on-site potential of the system, we can obtain the stable quasiperiodic discrete breathers (QDBs) and chaotic discrete breathers (CDBs) by changing the amplitude of the driver. But the DBs and QDBs with symmetric and anti-symmetric profiles that are centered at a heavy atom are more stable than at a light atom, because the frequencies of the DBs and QDBs centered at a heavy atom are lower than those centered at a light atom. 展开更多
关键词 discrete breather quasi-periodic discrete breather chaotic discrete breather two-dimensional discrete diatomic Klein-Gordon lattice
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基于立方型气体状态方程的激波风洞准一维流动数值研究
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作者 张洲铭 李贤 +3 位作者 朱雨建 李祝飞 龚红明 罗喜胜 《爆炸与冲击》 EI CAS CSCD 北大核心 2024年第2期99-115,共17页
采用基于立方型气体状态方程的准一维流动数值模拟方法研究了反射式高焓激波风洞的真实气体流动,重点关注了高压真实气体效应对风洞全场流动时空结构和驻室区气流参数的影响,并以理论分析揭示了高压真实气体效应对激波管内流动的作用机... 采用基于立方型气体状态方程的准一维流动数值模拟方法研究了反射式高焓激波风洞的真实气体流动,重点关注了高压真实气体效应对风洞全场流动时空结构和驻室区气流参数的影响,并以理论分析揭示了高压真实气体效应对激波管内流动的作用机理。研究表明:对于以冷高压气体驱动的激波风洞,使用考虑分子体积和分子间作用力的真实气体状态方程能够更准确地描述气体的状态和风洞内的流动状况。高压真实气体效应主要在冷驱动气体中发生作用,其作用效果主要是使当地声速增大,从而使得入射稀疏波和反射稀疏波的传播速度加快;另一方面,高压气体效应在高温气体效应较显著的被驱动气体中作用微弱,且对激波管产生激波的强度和激波后的流动状态影响甚微。稀疏波的加快传播改变了激波管波系的相干时空关系。提前抵达的稀疏波可在一定情况下侵蚀激波风洞的有效试验时间。对于所测试的激波风洞构型,在150 MPa氢气驱动110 kPa氮气的工况下,高压效应导致的有效试验时间缩短约38%。适当加长驱动段长度和采用高温气体驱动均可有效减弱高压真实气体效应的影响。 展开更多
关键词 激波风洞 高压真实气体效应 立方型气体状态方程 准一维数值模拟 有效试验时间
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准二维钙钛矿中结晶调控与低阈值微纳激光器
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作者 高华兴 张红旗 李璇 《材料导报》 EI CAS CSCD 北大核心 2024年第12期22-26,共5页
准二维(Q-2D)钙钛矿由于大的激子结合能和量子限域作用,是一种可以应用于光电器件构筑的有前途的材料。然而,Q-2D钙钛矿是具有丰富晶界和界面的多相结构,在能量传递过程中导致非辐射损耗。本工作通过操纵不同n相的结晶动力学过程,实现了... 准二维(Q-2D)钙钛矿由于大的激子结合能和量子限域作用,是一种可以应用于光电器件构筑的有前途的材料。然而,Q-2D钙钛矿是具有丰富晶界和界面的多相结构,在能量传递过程中导致非辐射损耗。本工作通过操纵不同n相的结晶动力学过程,实现了Q-2D钙钛矿中更高效的能量传递。通过在Q-2D钙钛矿前驱体中引入钠离子来实现对Q-2D钙钛矿成核和生长过程的操控。研究表明,钠离子的掺入促进高n相的成核,使不同n相在空间上更均匀地分布,寿命的表征证实该操作促进了能量的转移。得益于这种高效的能量传递过程,与普通薄膜体系的光放大阈值(23.3μJ·cm^(-2))相比,掺杂薄膜的光放大阈值降低至14.3μJ·cm^(-2)。该研究提供了一种有效的优化Q-2D钙钛矿光子学性能的新方法,从而进一步拓宽Q-2D钙钛矿的光子学应用范围。 展开更多
关键词 准二维钙钛矿 Na+掺杂 结晶调控 能量传递 微纳激光器
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基于准二维钙钛矿的窄线宽红光电致发光器件性能研究
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作者 张云杰 李晓丹 +1 位作者 郭晓阳 刘星元 《发光学报》 EI CAS CSCD 北大核心 2024年第8期1211-1218,共8页
金属卤化物钙钛矿发光二极管(PeLEDs)具有宽色域和高色纯度,在照明和显示方面有着广阔的应用前景。英国伦敦大学研究团队发表于Scientific Reports的一项开创性研究发现,每天只需暴露在红光下3 min,就能显著缓解视力下降。而钙钛矿的光... 金属卤化物钙钛矿发光二极管(PeLEDs)具有宽色域和高色纯度,在照明和显示方面有着广阔的应用前景。英国伦敦大学研究团队发表于Scientific Reports的一项开创性研究发现,每天只需暴露在红光下3 min,就能显著缓解视力下降。而钙钛矿的光谱可调性及较高的色纯度都为护眼红光PeLEDs的实现提供了保障。与以往的界面工程、配体工程等不同,本文从结构优化的角度来提升准二维钙钛矿红光PeLEDs的外量子效率(EQE),即结合微腔结构实现线宽更窄的红光电致发光器件。结果表明,将分布式布拉格反射镜(DBR)与PeLEDs相结合,设计并制备的基于微腔结构的高性能PeLEDs在窄化PeLED的电致发光(EL)半高全宽的基础上实现了EQE成倍增长,最大EQE能达到11.26%。相较于同条件下制备的参比器件,具有微腔结构的PeLED器件EL线宽窄化到参比器件的1/3,仅为11 nm。 展开更多
关键词 准二维钙钛矿 分布式布拉格反射镜 红光 电致发光 半高全宽
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基于准二维钙钛矿发光层优化的蓝色发光二极管研究进展
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作者 刘茜茜 韩鹏 张勇 《发光学报》 EI CAS CSCD 北大核心 2024年第10期1604-1612,共9页
金属卤化物钙钛矿材料因其简单的制备工艺和独特的光电性能,在照明、显示等光电子领域有着巨大的发展潜力。目前,钙钛矿发光二极管在绿光、红光等领域均取得了一定进展,然而实现高效率蓝色发光二极管仍存在较大挑战。近年来,研究人员主... 金属卤化物钙钛矿材料因其简单的制备工艺和独特的光电性能,在照明、显示等光电子领域有着巨大的发展潜力。目前,钙钛矿发光二极管在绿光、红光等领域均取得了一定进展,然而实现高效率蓝色发光二极管仍存在较大挑战。近年来,研究人员主要通过组分工程和维度工程两种途径实现钙钛矿蓝光调控。其中,准二维钙钛矿材料具有自组装量子阱结构,在蓝光发射方面表现出独特优势。由此,本文综述了目前准二维钙钛矿蓝色发光二极管的相关进展。首先阐述了准二维钙钛矿的结构和光学性质;重点从器件的发光层出发,系统地总结了提升器件性能的方法策略;然后围绕器件稳定性展开了相关描述;最后就准二维钙钛矿蓝色发光二极管的发展提出了部分总结和展望,期待其性能不断突破。 展开更多
关键词 准二维钙钛矿 发光层优化 蓝光 发光二极管
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准一维纳米发光材料制备与分析方法
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作者 洪春水 杨雷 《广东化工》 CAS 2024年第13期57-59,共3页
准一维纳米材料由于两个方向的限域作用,一维纳米材料的电子结构,能带结构与常规的微米材料不同,因而受到广泛的关注。对于纳米发光材料而言,将发光材料制成纳米材料后,材料的发光一般会明显减弱。当材料制成准一维纳米材料后,会大幅弥... 准一维纳米材料由于两个方向的限域作用,一维纳米材料的电子结构,能带结构与常规的微米材料不同,因而受到广泛的关注。对于纳米发光材料而言,将发光材料制成纳米材料后,材料的发光一般会明显减弱。当材料制成准一维纳米材料后,会大幅弥补这一缺陷。另一方面,准一维纳米发光材料会因为表面原子排列较为疏松,容易出现各种晶体缺陷,而出现常规材料不会出现的光学性能。所以准一维纳米发光材料的研究,受到广泛的兴趣。本文将综述准一维纳米材料的发展历史、制备方法和分析表征方法。 展开更多
关键词 准一维纳米材料 表面效应 扫描电镜 透射电镜 光谱分析
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NONLINEAR DYNAMICAL STABILITY ANALYSIS OF THE CIRCULAR THREE-DIMENSIONAL FRAME
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作者 王新志 王钢 +1 位作者 赵艳影 叶开沅 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2004年第4期367-372,共6页
The three-dimensional frame is simplified into flat plate by the method of quasi-plate. The nonlinear relationships between the surface strain and the midst plane displacement are established. According to the thin pl... The three-dimensional frame is simplified into flat plate by the method of quasi-plate. The nonlinear relationships between the surface strain and the midst plane displacement are established. According to the thin plate nonlinear dynamical theory, the nonlinear dynamical equations of three-dimensional frame in the orthogonal coordinates system are obtained. Then the equations are translated into the axial symmetry nonlinear dynamical equations in the polar coordinates system. Some dimensionless quantities different from the plate of uniform thickness are introduced under the boundary conditions of fixed edges, then these fundamental equations are simplified with these dimensionless quantities. A cubic nonlinear vibration equation is obtained with the method of Galerkin. The stability and bifurcation of the circular three-dimensional frame are studied under the condition of without outer motivation. The contingent chaotic vibration of the three-dimensional frame is studied with the method of Melnikov. Some phase figures of contingent chaotic vibration are plotted with digital artificial method. 展开更多
关键词 three-dimensional frame quasi-plate method BIFURCATION CHAOS
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并联型TBCC推进系统变维度一体化数值模拟方法研究 被引量:1
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作者 刘君 袁化成 张锦昇 《推进技术》 EI CAS CSCD 北大核心 2023年第1期16-24,共9页
为了缩短组合动力系统内外流一体化数值仿真时间,加快高超声速飞行器的研制进度,基于商业软件发展了一种飞行器进/排气系统多维仿真与发动机等效一维模型相结合的TBCC推进系统变维度一体化数值仿真方法,其中进/排气系统采用多维数值仿真... 为了缩短组合动力系统内外流一体化数值仿真时间,加快高超声速飞行器的研制进度,基于商业软件发展了一种飞行器进/排气系统多维仿真与发动机等效一维模型相结合的TBCC推进系统变维度一体化数值仿真方法,其中进/排气系统采用多维数值仿真,涡轮发动机采用部件特性的数学模型,冲压发动机采用准一维数学模型,结合商业软件通过边界条件调用,实现变维度一体化数值仿真。数值仿真对比分析表明:TBCC推进系统等效一维模型模拟结果与GasTurb 10和风洞试验结果变化规律一致吻合较好,误差不大于3.0%;采用变维度数值模拟方法对某TBCC推进系统沿飞行轨迹加速爬升过程的分析表明,进气道总收缩比从2.0增大到5.5,喷管面积比从1.2增大到7.8。涡轮模态时,TBCC喷管出现明显过膨胀现象;冲压模态时,喷管的落压比随马赫数增大从8.3逐渐增大至20.4,过膨胀现象减弱,从而验证了多维与一维耦合数值仿真方法的可行性。 展开更多
关键词 TBCC推进系统 内外流一体化 变维度数值仿真 涡轮发动机模型 准一维冲压发动机模型
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利用多氟丙烯酸酯添加剂提升准二维钙钛矿发光二极管性能
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作者 张涛 龚思敏 +2 位作者 陈平 陈琪 陈立桅 《物理化学学报》 SCIE CAS CSCD 北大核心 2023年第12期87-94,共8页
准二维钙钛矿由于具有较大的激子结合能和高效的能量转移等优势,在发光二极管(light-emitting diodes,LED)中的应用前景被广泛看好。然而,准二维钙钛矿溶液加工成膜过程中易形成大量的低维相和表界面缺陷,引起严重的非辐射复合,成为限... 准二维钙钛矿由于具有较大的激子结合能和高效的能量转移等优势,在发光二极管(light-emitting diodes,LED)中的应用前景被广泛看好。然而,准二维钙钛矿溶液加工成膜过程中易形成大量的低维相和表界面缺陷,引起严重的非辐射复合,成为限制发光二极管器件性能的瓶颈。在本工作中,通过在PEA2Cs2Pb3Br10钙钛矿前驱体中加入1,6-二(丙烯酰氧基)-2,2,3,3,4,4,5,5-八氟己烷(OFHDODA)小分子添加剂,将钙钛矿薄膜的荧光量子效率(Photoluminescence Quantum Yield,PLQY)从19.7%提升到了49.0%,发射波长从508 nm红移到511 nm。这主要归因于OFHDODA与钙钛矿之间的物理化学相互作用有效抑制了非辐射复合,一方面多氟结构与PEA+之间的氢键相互作用调控了结晶动力学,抑制了低维相的产生;另一方面酯基具有较强的路易斯碱性,钝化了表界面未饱和Pb2+缺陷。相应地,准二维钙钛矿LED的外量子效率(External Quantum Efficiency,EQE)从8.55%提高到了13.76%。这项工作为设计新型多功能小分子添加剂,抑制准二维钙钛矿中的非辐射复合损失提供了思路。 展开更多
关键词 准二维钙钛矿 非辐射复合 低维相抑制 缺陷钝化 多氟丙烯酸酯添加剂
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Heuristic Quasi-physical Algorithm for Protein Structure Prediction
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作者 刘景发 黄文奇 《Journal of Southwest Jiaotong University(English Edition)》 2006年第4期308-314,共7页
A three-dimensional off-lattice protein model with two species of monomers, hydrophobic and hydrophilic, is studied. Enligh- tened by the law of reciprocity among things in the physical world, a heuristic quasi-physic... A three-dimensional off-lattice protein model with two species of monomers, hydrophobic and hydrophilic, is studied. Enligh- tened by the law of reciprocity among things in the physical world, a heuristic quasi-physical algorithm for protein structure prediction problem is put forward. First, by elaborately simulating the movement of the smooth elastic balls in the physical world, the algorithm finds low energy configurations for a given monomer chain. An "off-trap" strategy is then proposed to get out of local minima. Experimental results show promising performance. For all chains with lengths 13≤n ≤55, the proposed algorithm finds states with lower energy than the putative ground states reported in literatures. Furthermore, for chain lengths n = 21, 34, and 55, the algorithm finds new low energy configurations different from those given in literatures. 展开更多
关键词 Protein structure prediction Three-dimensional protein model quasi-physical algorithm HEURISTICS
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Unique Common Fixed Point for a Family of Mappings with a Nonlinear Quasi-Contractive Type Condition in Metrically Convex Spaces
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作者 Yongjie Piao 《Analysis in Theory and Applications》 CSCD 2015年第2期167-175,共9页
A class Ф of 5-dimensional functions was introduced and an existence and uniqueness of common fixed points for a family of non-self mappings satisfying a Фi- quasi-contractive condition and a certain boundary condit... A class Ф of 5-dimensional functions was introduced and an existence and uniqueness of common fixed points for a family of non-self mappings satisfying a Фi- quasi-contractive condition and a certain boundary condition was given on complete metrically convex metric spaces, and from which, more general unique common fixed point theorems were obtained. Our main results generalize and improve many same type common fixed point theorems in references. 展开更多
关键词 Metrically convex space a class Ф of 5-dimensional functions Фi-quasi-contraction common fixed point complete.
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类回转预制体针刺机器人系统设计 被引量:1
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作者 李皎 陈利 +1 位作者 姚天磊 陈小明 《纺织学报》 EI CAS CSCD 北大核心 2023年第7期207-213,共7页
类回转复合材料预制体外形结构复杂,目前的4轴针刺系统和6关节机器人针刺成型系统难以满足其成型织造要求,提出一种基于机器人平台的7轴联动针刺成型系统,用于类回转预制体的针刺成型。开展了7轴针刺成型系统的机械结构设计、控制系统设... 类回转复合材料预制体外形结构复杂,目前的4轴针刺系统和6关节机器人针刺成型系统难以满足其成型织造要求,提出一种基于机器人平台的7轴联动针刺成型系统,用于类回转预制体的针刺成型。开展了7轴针刺成型系统的机械结构设计、控制系统设计,以及针刺轨迹规划方法研究,并通过运动仿真和实验验证系统的可行性。结果表明:针刺实验轨迹和理论设计轨迹高度一致,针迹均匀,预制体表面平整,7轴联动针刺成型系统成功实现了类回转预制体的高质量针刺成型;采用Powershape和Powermill软件成功实现了连续轨迹线设计和针刺机器人6轴程序输出;自主开发的6轴程序转换成7轴程序的算法是可靠的,基于Python和QT Designer开发的7轴针刺机器人程序后处理软件成功实现了7轴针刺机器人可执行程序的高精确输出。本文系统可用于高速飞行器天线罩、舱段等复合材料预制体的高质量针刺成型。 展开更多
关键词 类回转预制体 针刺机器人 系统设计 三维针刺复合材料 结构设计
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