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Chinese Physics B 2024年第7期33卷 429-439页

作者： Jackson Pame Lenin S.Shagolsem Department of Physics National Institute of Technology Manipur

We study the effect of particle size polydispersity（δ） on the melting transition（T*）, local ordering, solid–liquid coexistence phase and dynamics of two-dimensional Lennard–Jones fluids up to moderate polydispersity by means of computer simulations. The particle sizes are drawn at random from the Gaussian（G） and uniform（U） distribution functions.For these systems, we further consider two different kinds of particles, viz., particles having the same mass irrespective of size, and in the other case the mass of the particle scales with its size. It is observed that with increasing polydispersity,the value of T*initially increases due to improved packing efficiency（φ） followed by a decrease and terminates at δ ≈8%（U-system） and 14%（G-system） with no significant difference for both mass types. The interesting observation is that the particular value at which φ drops suddenly coincides with the peak of the heat capacity（CP） curve, indicating a transition. The quantification of local particle ordering through the hexatic order parameter（Q6）, Voronoi construction and pair correlation function reveals that the ordering decreases with increasing δ and T. Furthermore, the solid–liquid coexistence region for the G-system is shown to be comparatively wider in the T –δ plane phase diagram than that for the U system. Finally, the study of dynamics reveals that polydisperse systems relax faster compared to monodisperse systems;however, no significant qualitative differences, depending on the distribution type and mass polydispersity, are observed.

关键词： dynamics ordering phase diagram polydispersity

ordering Graphs with Cut Edges by Their Spectral Radii

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Acta Mathematicae Applicatae Sinica 2012年第1期28卷 193-200页

作者： Kun-fu FANG Faculty of Science Huzhou Teachers CollegeHuzhou 313000China

Let gnk denote a set of graphs with n vertices and k cut edges. In this paper, we obtain an order of the first four graphs in gnk in terms of their spectral radii for 6 ≤ k ≤ n-2/3.

关键词： spectral radius cut edge ordering eigenvalue

ordering Trees by Their Spectral Radii

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Acta Mathematicae Applicatae Sinica 2014年第4期30卷 1107-1112页

作者： Ai-mei YU Department of Mathematics Beijing Jiaotong University

Let T be a tree with n vertices and let A（T） be the adjacency matrix of T. Spectral radius of T is the largest eigenvalue of A（T）. Wu et al. [Wu, B.F., Yuan, X.Y, and Xiao, E.L. On the spectral radii of trees, Journal of East China Normal University （Natural Science）, 3：22-28 （2004）] determined the first seven trees of order n with the smallest spectral radius. In this paper, we extend this ordering by determining the trees with the eighth to the tenth smallest spectral radius among all trees with n vertices.

关键词： tree spectral radius ordering

Back-to-Front ordering of Triangles in Digital Terrain Models over Regular Grids

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Journal of Computer Science & Technology 2018年第6期33卷 1192-1203页

作者： Jesús Alonso Robert Joan-Arinyo Informatics in Engineering Group Technical University of Catalonia 08028 Barcelona Catalonia Center for Biomedical Engineering Research Sant Joan de Ddu Research Institute 08028 Barcelona Catalonia Visualization Interaction and Virtual Reality Group Technical University of Catalonia 08028 Barcelona Catalonia

Visiting triangles that conform a digital terrain model is a core operation in a number of fields like animationand video games or generating profiles, cross-sections, and contours in civil engineering. Perfornfing the visit in an efficientmanner is an issue specially when the output of the traversal depends in some way on additional parameters or informationchanging over time, for example, a moving point of view. In this work we report a set of rules that, given a digital terrainmodel defined over a regular grid and an arbitrary point of view outside the terrain, define a total back-to-front order in theset of digital terrain model triangles with respect to the point. The set of rules is minimal, complete and correct. To assesshow the rules perform, we have implemented a CPU-based algorithm for realistically rendering height fields defined overregular grids. The algorithm does not make use of the z-buffer or shaders featured by our graphics card. We show how ouralgorithm is implemented and show visual results obtained from synthetic and real data. We further discuss the algorithmperformance with respect to two algorithms： a naive algorithm that visits triangles according to grid indices and does notsolve the hidden line problem, and the z-buffer provided by the graphics card featured by our computer. Our algorithmallows real-time interaction when the point of view arbitrarily moves in 3D space and we show that its performance is asgood as that of the z-buffer graphics card.

关键词： back-to-front ordering digital terrain model elevation terrain model triangle strip, visibility

“BUTTERFLY” PRECIPITATES IN δ-TiN_(0.53)→δ’-TiN_(0.53) ordering TRANSFORMATION①

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中国有色金属学会会刊：英文版 1996年第2期6卷 57-60页

作者： Du Jun Yang Gaiying Portier R Shi Likai (General Research Institute for Non-Ferrous Metals, Beijing 100088 Ecole Nationale Superieure de Chimie de Paris, 75231 Paris, France) General Research Institute for Non-Ferrous Metals Beijing 100088 China Ecole Nationale Superieure de Chimie de Paris 75231 Paris France

“ＢＵＴＴＥＲＦＬＹ”ＰＲＥＣＩＰＩＴＡＴＥＳＩＮδ－ＴｉＮ_（０．５３）→δ’－ＴｉＮ_（０．５３）ＯＲＤＥＲＩＮＧＴＲＡＮＳＦＯＲＭＡＴＩＯＮＤｕＪｕｎ；ＹａｎｇＧａｉｙｉｎｇ；ＰｏｒｔｉｅｒＲ；ＳｈｉＬｉｋａｉ（... 详细信息

“ＢＵＴＴＥＲＦＬＹ”ＰＲＥＣＩＰＩＴＡＴＥＳＩＮδ－ＴｉＮ_（０．５３）→δ’－ＴｉＮ_（０．５３）ＯＲＤＥＲＩＮＧＴＲＡＮＳＦＯＲＭＡＴＩＯＮＤｕＪｕｎ；ＹａｎｇＧａｉｙｉｎｇ；ＰｏｒｔｉｅｒＲ；ＳｈｉＬｉｋａｉ（ＧｅｎｅｒａｌＲｅｓｅａｒｃｈＩｎ...

关键词： butterfly”precipitates δ’-TiN0.53 ordering transformation

Condition-Based Spare ordering Model for a Two-Stage Degrading System

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Journal of Systems Science and Systems Engineering 2020年第1期29卷 85-99页

作者： Cheng Wang Jianxin Xu Zhenming Zhang Hongjun Wang School of Mechanical Engineering Xi'an Aeronautical UniversityXi'an 710077China School of Mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China Key Laboratory of Modern Measurement and Control Technology Ministry of EducationBeijing Information Science and Technology UniversityBeijing 100192China

Proper supply of spares is critical to guarantee safe operation,improve service quality and reduce maintenance costs.This paper proposes a condition-based spare ordering model for a two-stage degrading system,which consists of inflection point transfer process and two-stage degradation process with continuous degradation process and random external shocks.External shocks itself does not directly lead to system failure,but it will speed up the degradation process.In turn,degradation can also make the system more vulnerable to shocks.In general,the degradation rate at the defective stage is greater than that at the normal stage.The proposed model depends on system degradation process and spare lead-time.In order to achieve accurate maintenance and deal with emergency maintenance caused by system rapid degradation after inflection point transfer time,the model considers both the regular lead-time and expedited lead-time.Before inflection point transfer time,regular spare ordering policy is performed.After inflection point transfer time,expedited spare ordering policy is implemented.The decision variable of the model is the ordering time.The objective of this study is to determine the optimal ordering time such that the expected cost rate is minimized.Finally,a numerical example is presented to illustrate the proposed model and sensitivity analysis on critical parameters is carried out.

关键词： Condition-based spare ordering inflection point two-stage degradation random external shocks random lead-time

The ordering and Replacement Policy for the System with Two Types of Failures

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Journal of Systems Science & Complexity 2018年第6期31卷 1541-1553页

作者： GAO Qiaoqiao YUE Dequan ZHAO Bing School of Economics and Management Shanxi UniversityTaiyuan 030006China College of Science Yanshan UniversityQinhuangdao 066004China.

In this paper,the optimal maintenance policy is investigated for a system with stochastic lead time and two types of failures. The system has two types of failures, one type is repairable, when the repairable failure occurs, the system will be repaired by repairman, and the system after repair is not“as good as new". The other type of failure is unrepairable, and when the unrepairable failure occurs the system must be replaced by a new and identical one. The spare system for replacement is available only by order, and the lead time for delivering the spare system is stochastic. The successive survival times of the system form a stochastically decreasing geometric process, the consecutive repair times after failures of the system form a renewal process. By using the renewal process theory and geometric process theory, the explicit expression of the long-run average cost per unit time under ordering policy (N-1) is derived, and the corresponding optimal can be found analytically. Finally, the numerical analyses are given.

关键词： Failure repair geometric process ordering policy renewal process replace.

Regression model for stabilization energies associated with anion ordering in perovskite-type oxynitrides

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Journal of Energy Chemistry 2019年第9期28卷 7-14页

作者： Masanori Kaneko Mikiya Fujii Takashi Hisatomi Koichi Yamashita Kazunari Domen Department of Chemical System Engineering School of Engineering The University of Tokyo7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan Center for Energy & Environmental Science Interdisciplinary Cluster for Cutting Edge Research Shinshu University4-17-1 Wakasato Nagano-shi Nagano 380-8553 Japan

Certain perovskite-type oxynitrides have bandgaps suitable for renewable hydrogen production via photocatalytic and photoelectrochemical water splitting under visible light.Understanding the ordering of oxide and nitride anions in these materials is important because this ordering affects their semiconductor properties.However, the numerous possible orderings complicate systematic analyses based on density functional theory(DFT) calculations using defined elemental arrangements.This work shows that anion ordering in large-scale supercells within perovskite-type oxynitrides can be rapidly predicted based on machine learning, using BaNbO2N(capable of oxidizing water under irradiation up to 740 nm) as an example.Machine learning allows the calculation of the total energy of BaNbO2N directly from randomly selected initial atomic placements without costly structural optimization, thus reducing the computational cost by more than 99.99%.Combined with the Metropolis Monte Carlo method, machine learning permits exploration of the stable anion orderings of large supercells without costly DFT calculations.This work therefore demonstrates a means of predicting the properties of functional materials having complex compositions based on the most realistic elemental arrangements in conjunction with reasonable computational loads.

关键词： Machine learning Total energy Bandgap Local anion ordering Density functional theory

Influence of GaInP ordering on the performance of GaInP solar cells

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Journal of Semiconductors 2016年第7期37卷 31-34页

作者：于淑珍董建荣赵勇明孙玉润李奎龙曾徐路杨辉 Key Laboratory of Nanodevices and Applications Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China University of Chinese Academy of Sciences Beijing 100049China

CuPt-type ordering with undesirable properties always occurs in GaInP at growth conditions that are very close to those leading to the highest quality material in metal organic chemical vapor deposition. In this work, highly disordered GaInP with high crystalline quality was obtained by optimizing growth conditions. Room- temperature and low-temperature photoluminescence （PL） spectra of A1GalnP/GaInP/A1GaInP double heterostruc- tures （DHs） reveal that the band edge emission intensity is enhanced by optimizing growth temperature, V/III ratio, and reactor pressure at the expense of low energy peak originating from spatially indirect recombination due to the ordering-related defects. The DH sample with less ordering-related defects demonstrates a longer effective minority carrier lifetime, consequently, the GaInP solar cell shows a significant improvement in the performance.

关键词： MOCVD GaInP ordering solar cell

STABILIZATION OF MARTENSITE AND PARENT PHASE ordering IN A Cu-Zn-Al ALLOY

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Acta Metallurgica Sinica(English Letters) 1992年第1期5卷 1-6页

作者： Chen Shuchuan Xu Zuyao Yang Fan Zhang Jihua Shangbai Jiaotong Univ Shanghai China

The reverse transformation has never occurred in a quenched and aged specimen upon heating from room temperature to 320℃ at which the martensite disappears thoroughly.Both B2 9R and DO_318R coexist in step-quenched and short-time isothermally treated specimen. As prolonging the isothermal holding,the B29R disappears and DO_318R intensifies. B29R occurs only in specimen quenched and up-quenched immediately to 100—150℃. Rapid quenching from high temperatures will depress the B2→DO_3 ordering but not the A2 →B2 one.A plenty enough concentration of vacancy is a necessary condition of occurrence of B2→DO_3 ordering.The possible mechanism for the stabilization of martensite in a Cu-Zn-Al alloy was also discussed.

关键词： stabilization of martensite ordering vacancy concentration