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A three-dimensional numerical study on instability of sinusoidal flame induced by multiple shock waves

Acta Mechanica Sinica 2017年第2期33卷 316-326页

作者： Xiao chen Gang Dong Hua Jiang Key Laboratory of Transient Physics Nanjing University of Science and Technology Nanjing 210094 China

The instabilities of a three-dimensional sinusoidally premixed flame induced by an incident shock wave with Mach = 1.7 and its reshock waves were studied by using the Navier-Stokes (NS) equations with a single-step chemical reaction and a high resolution, 9th-order weighted essentially non-oscillatory scheme. The computational results were validated by the grid independence test and the experimental results in the literature. The computational results show that after the passage of incident shock wave the flame interface develops in symmetric structure accompanied by large-scale transverse vortex structures. After the interactions by successive reshock waves, the flame interface is gradually destabilized and broken up, and the large-scale vortex structures are gradually transformed into small-scale vortex structures. The small-scale vortices tend to be isotropic later. The results also reveal that the evolution of the flame interface is affected by both mixing process and chemical reaction. In order to identify the relationship between the mixing and the chemical reaction, a dimensionless parameter, , that is defined as the ratio of mixing time scale to chemical reaction time scale, is introduced. It is found that at each interaction stage the effect of chemical reaction is enhanced with time. The enhanced effect of chemical reaction at the interaction stage by incident shock wave is greater than that at the interaction stages by reshock waves. The result suggests that the parameter can reasonably character the features of flame interface development induced by the multiple shock waves.

关键词： Shock wave Flame interface RM instability Chemical reaction Vortex structure

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Performance analysis of UAV-based mixed underwater PLC-RF systems

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Digital Communications and Networks 2024年第5期10卷 1332-1340页

作者： Shenghai chen Liang Yang Xianfu Lei College of Computer Science and Electronic Engineering Hunan University Key Laboratory of Intelligent Control Technology for Wuling-Mountain Ecological Agriculture in Hunan Province Huaihua University School of Information Science and Technology Southwest Jiaotong University

In this study,we analyzed the performance of an Unmanned Aerial Vehicle(UAV)-based mixed Underwater Power Line Communication-Radio Frequency(UPLC-RF) *** this network,a buoy located at the sea is used as a relay to transmit signals from the underwater signal source to the UAV through the PLC *** assume that the UPLC channel obeys a log-normal distribution and that the RF link follows the Rician *** this model,we obtained the closed-form expressions for the Outage Probability(OP),Average Bit-error-rate(ABER),and Average Channel Capacity(ACC).In addition,the asymptotic analysis of the OP and ABER was performed,and an upper bound for the average capacity was ***,the analytical results were verified by Monte Carlo simulation thereby demonstrating the effect of impulse noise and the altitude of the UAV on network performance.

关键词： ABER Underwater power line communication Average bit-error-rate ACC Average channel capacity OP Outage probability UAV Unmanned aerial vehicle UPLC

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STrans:A Comprehensive Framework for Structure Transformation

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Tsinghua Science and Technology 2016年第2期21卷 231-240页

作者： Jiangzhou He Wenguang chen Zhizhong Tang Department of Computer Science and Technology Tsinghua National Laboratory for Information Science and TechnologyTsinghua UniversityBeijing 100084China Google lnc 1600 Amphitheatre PkwyMountain ViewCA 94043USA. Research Institute of Tsinghua University in Shenzhen Shenzhen 518057China

Structure Data Layout Optimization （SDLO） is a prevailing compiler optimization technique to improve cache efficiency. Structure transformation is a critical step for SDLO. Diversity of transformation methods and existence of complex data types are major challenges for structure transformation. We have designed and implemented STrans, a well-defined system which provides controllable and comprehensive functionality on structure transformation. Compared to known systems, it has less limitation on data types for transformation. In this paper we give formal definition of the approach STrans transforms data types. We have also designed Transformation Specification Language, a mini language to configure how to transform structures, which can be either manually tuned or generated by compiler. STrans supports three kinds of transformation methods, i.e., splitting, peeling, and pool-splitting, and works well on different combinations of compound data types. STrans is the transformation system used in ASLOP and is well tested for all benchmarks for ASLOR

关键词： Structure Data Layout Optimization (SDLO) STrans ASLOP structure transformation

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Mechanical model of organ of Corti

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Applied Mathematics and Mechanics(English Edition) 2017年第6期38卷 867-876页

作者： Yiqiang chen Wenjuan YAO Shaofeng LIU Department of Civil Engineering Shanghai University

According to the vibration characteristics of the organ of Corti （OC）, seven hypotheses are made to simplify the structure of the model, and a mechanical OC model is established. Using the variational principle, a displacement analytical expression is solved under a certain pressure. The results are in good agreement with experimental data, showing the validity of the formula. Combined with the damage caused by noise in clinic, it is found that the hardening of outer hair cells and outer stereocilia can lead to loss of hearing and generation of threshold shift. In addition, the results show that high frequency resonance occurs at the bottom of the basilar membrane （BM）, and low frequency resonance occurs at the top of the BM. This confirms the frequency selective characteristics of the BM. Further, using this formula can avoid interference of the envi- ronment and the technical level of the test personnel, and can evaluate performance of the OC objectively.

关键词： organ of Corti (OC) variational principle hardening of outer hair cells(OHCs) hardening of outer stereocilia threshold shift

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DYNAMIC PRICING AND COMPENSATION ON HETEROGENEOUS SALES FORCES

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Journal of Systems Science and Systems Engineering 2012年第2期21卷 204-225页

作者： Hongyan XU He HUANG Jian chen School of Economics and Business Administration Chongqing UniversityChongqing400044China Chongqing Key Laboratory of Logistics Chongqing UniversityChongqing400044China School of Economics and Management Tsinghua UniversityBeijing100084China

In this paper, we analyze the pricing decision and the compensation strategy of a firm that relies on a heterogeneous sales force to sell its product in two periods. The sales agents＇ selling abilities are their private information and will determine the effectiveness of the agents＇ selling efforts. We introduce three compensation contract strategies, i.e. pooling, semi-separating and separating that the firm can adopt in period one and by applying principle-agent theory, derive the optimal compensation contracts and optimal price for the firm in two periods in each strategy. Compai＇ing these three contract strategies, we found that the optimal strategy for the firm depends on the discount factor. We show that the firm will surely offer separating contracts in period one for some small discount factor, and for some large discount factor pooling contract is certain to be provided in period one. However, semi-separating contracts may be considered for some mediate discount factor, and also may not appear for all discount factors in period one. Our analysis also reveals that the optimal price decreases with the discount factor when pooling contract is offered in period one and increases with the discount factor when separating contracts is offered in period one.

关键词： Sales force sales effort selling abilities pricing

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Binary Population Synthesis

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Research in Astronomy and Astrophysics 2020年第10期20卷 207-220页

作者： Zhan-Wen Han Hong-Wei Ge Xue-Fei chen Hai-Liang chen Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of the Chinese Academy of Sciences Beijing 100049China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China

Binary interactions lead to the formation of intriguing objects,such as compact binaries,supernovae,gamma ray bursts,X-ray binaries,pulsars,novae,cataclysmic variables,hot subdwarf stars,barium stars and blue *** study the evolution of binary populations and the consequent formation of these objects,many methods have been developed over the years,for which a robust approach named binary population synthesis(BPS)warrants special *** approach has seen widespread application in many areas of astrophysics,including but not limited to analyses of the stellar content of galaxies,research on galactic chemical evolution and studies concerning star formation and cosmic *** this review,we discuss the role of BPS,its general picture and the various components that comprise *** pay special attention to the stability criteria for mass transfer in binaries,as this stability largely determines the fate of binary *** conclude with our perspectives regarding the future of this field.

关键词： stars evolution-star binaries(including multiple) close-stars statistics-supernovae general-galaxies stellar content-methods numerical

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A CASE STUDY FOR ADVANCED PLANNING AND SCHEDULING (APS)

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Journal of Systems Science and Systems Engineering 2011年第4期20卷 460-474页

作者： Kejia chen Ping Jl Qing WANG School of Management Fuzhou University Fuzhou 350108 China Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong Department of Systems Engineering Northeastern University Shenyang 110819 China

This paper presents a case study for the advanced planning and scheduling （APS） problem encountered in a light source manufacturer. The APS problem explicitly considers due dates of products, operation sequences among items, and capacity constraints of the manufacturing system. The objective of the problem is to seek the minimum cost of both production idle time and tardiness or earliness penalty of an order. An intelligent heuristic is applied to the problem, and the results demonstrate that significant production performances can be achieved while ensuring customer satisfaction as opposed to normal oractices followed in the company relying on human expertise.

关键词： Advanced planning and scheduling case study intelligent heuristic

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Measurement of length-scale and solution of cantilever beam in couple stress elasto-plasticity

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Acta Mechanica Sinica 2009年第3期25卷 381-387页

作者： Bin Ji Wanji chen Jie Zhao State Key Laboratory for Structural Analysis of Industrial Equipment Dalian University of Technology 116023 Dalian China Department of Aeronautics and Space Navigation Shenyang Institute of Aeronautical Engineering Daoyi South Street 37 110136 Shenyang Liaoning China

Owing to the absence of proper analytical solution of cantilever beams for couple stress/strain gradient elasto-plastic theory, experimental studies of the cantilever beam in the micro-scale are not suitable for the determination of material length-scale. Based on the couple stress elasto-plasticity, an analytical solution of thin cantilever beams is firstly presented, and the solution can be regarded as an extension of the elastic and rigid-plastic solutions of pure bending beam. A comparison with numerical results shows that the current analytical solution is reliable for the case of σ0 〈〈 H 〈〈 E, where σ0 is the initial yield strength, H is the hardening modulus and E is the elastic modulus. Fortunately, the above mentioned condition can be satisfied for many metal materials, and thus the solution can be used to determine the material length-scale of micro-structures in conjunction with the experiment of cantilever beams in the micro-scale.

关键词： Material length-scale Couple stress elasto-plasticity Analytical solution Cantilever beam

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Controllable synthesis of polyoxovanadate-based coordination polymer nanosheets with extended exposure of catalytic sites

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Nano Research 2016年第12期9卷 3858-3867页

作者： Aruuhan Bayaguud Kun chen Yongge Wei Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education Department of Chemistry Tsinghua University Beijing 100084 China State Key Laboratory of Natural and Biomimetic Drugs Peking University Beijing 100191 China

Two-dimensional nanomaterials have become a hot research topic, and progress in research on them in the past decade has been substantial. Here we demonstrate a molecule-based bottom-up method to synthesize freestanding polyoxometalate- based nanosheets in two different ways. The trans substitution of ligands with carboxylate functionality promoted the coordination of organically derivatized hexavanadate with zinc ions with preferential directionality, which led to the formation of coordination polymer nanosheets. Characterization with transmission electron microscopy, powder X-ray diffraction, and infrared spectroscopy confirmed the morphology, structural composition, and preferential direction of the nanosheets. The microwave-assisted heating method and solvent addition method were proved to be effective for the preparation of POM-based nanosheet structures. The nanosheets were found to catalyze the aerobic oxidation of propanethiol （n-PrSH） to its corresponding disulfide （PrSSPr） under mild conditions.

关键词： polyoxometalate nanosheet bottom-up catalysis

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Interval optimal power flow applied to distribution networks under uncertainty of loads and renewable resources

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Journal of Modern Power Systems and Clean Energy 2019年第1期7卷 139-150页

作者： Pengwei chen Xiangning XIAO Xuhui WANG North China Electric Power University Hefei University of Technology

Optimal power flow(OPF) has been used for energy dispatching in active distribution *** satisfy constraints fully and achieve strict operational bounds under the uncertainties from loads and sources, this paper derives an interval optimal power flow(I-OPF)method employing affine arithmetic and interval Taylor *** enhanced I-OPF method based on successive linear approximation and second-order cone programming is developed to improve solution *** proposed methods are benchmarked against Monte Carlo simulation(MCS) and stochastic *** on a modified IEEE 33-bus system and a real 113-bus distribution network validate the effectiveness and applicability of the proposed methods.

关键词： Active distribution network Optimal power flow Interval uncertainty Affine arithmetic Second-order cone programming

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