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低轨卫星高能效载波功率资源联合调度算法

空间电子技术 2022年第2期19卷 16-22页

作者：孟恩同于季弘卜祥元安建平马永锋北京理工大学空天网络信息技术实验室北京100081

结合多波束低轨(multi-beam low earth orbit,MB-LEO)卫星通信场景,研究了一种多目标载波功率联合优化(joint subcarrier scheduling and power control resource allocation,JSSPC-RA)算法。通过求解整数混合规划非凸优化问题,得到了不同通信需求下MC-DS-CDMA子载波和子载波功率的联合调度方案,实现了系统用户未满足容量和卫星总功耗的最小化。仿真结果表明,相对于传统的载波功率均分策略,JSSPC-RA算法能够在满足系统吞吐量需求的前提下大幅节省卫星总功耗;同时,通过调节权值系数,JSSPC-RA算法可以生成用户吞吐量需求与卫星总能耗折中的系统设计方案,适用于频谱、能量资源高度受限的MB-LEO卫星系统。

关键词：多波束低轨卫星通信 MC-DS-CDMA 联合资源优化

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BIM技术在混凝土预制构件设计中的应用

建设监理 2023年第4期 68-70页

作者：章海瑛彭文勇卜向远蒋泽南丁康俊杭州市城建设计研究院有限公司法浙江杭州310006 浙江工程建设管理有限公司浙江杭州310006 五洲工程顾问集团有限公司浙江杭州310051

在满足初步设计阶段装配率的前提下,如何快速、便捷、准确、规范地深化生产预制构件是现阶段面临的重点问题。应用BIM软件开发来做好预制构件上的预留孔洞标识及洞口结构加固措施以保证建筑工程高效生产运行的方式,在现阶段BIM技术应用... 详细信息

在满足初步设计阶段装配率的前提下,如何快速、便捷、准确、规范地深化生产预制构件是现阶段面临的重点问题。应用BIM软件开发来做好预制构件上的预留孔洞标识及洞口结构加固措施以保证建筑工程高效生产运行的方式,在现阶段BIM技术应用中得到了广泛挖掘和运用。

关键词： BIM技术装配式混凝土预制构件关键成果

Study on periodic orbits around the dipole segment model for dumbbell-shaped asteroids

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Science China(Technological Sciences) 2018年第6期61卷 819-829页

作者： ZHANG YongLong ZENG xiangyuan LIU XiangDong School of Automation Beijing Institute of Technology Beijing 100081 China

Equilibrium points and periodic orbits in irregular gravitational fields are significant for an understanding of dynamical behaviors around asteroids as well as deep space exploring missions. The dipole segment is a good alternative model to study qualitative dynamical properties near dumbbell-shaped asteroids. In this paper, the dipole segment model and its equilibrium points are simply introduced. The stability of the two triangular equilibrium points of the system is numerically examined. Next, periodic orbits are presented around the dipole segment model in two different cases, in which triangular equilibria are linearly stable and unstable,respectively. New types of periodic orbits are illustrated in detail, including their orbital shapes, periods and the Jacobi *** orbital stability, topological classification and bifurcations of these orbits are also analyzed with numerical continuations.

关键词： dipole segment model equilibrium points periodic orbits topological classification

CONIC TRUST REGION METHOD FOR LINEARLY CONSTRAINED OPTIMIZATION

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Journal of Computational Mathematics 2003年第3期21卷 295-304页

作者： Wen-yuSun Jin-yunYuan Ya-xiangyuan SchoolofMathematicsandComputerScience NanjingNormalUniversityNanjing210097China DepartmentofMathematics FederalUniversityofParanaCuritibaPR81531-990Brazil LSEC ICMSECAcademyofMathematicsandSystemSciencesChineseAcademyofSciencesBeijing100080China

In this paper we present a trust region method of conic model for linearly constrained optimization problems. We discuss trust region approaches with conic model subproblems. Some equivalent variation properties and optimality conditions are given. A trust region algorithm based on conic model is constructed. Global convergence of the method is established.

关键词： Trust region method Conic model Constrained optimization.

Causal constraint pruning for exact learning of Bayesian network structure

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Journal of Systems Engineering and Electronics 2021年第4期32卷 854-872页

作者： TAN xiangyuan GAO Xiaoguang HE Chuchao WANG Zidong School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China School of Electronics and Information Engineering Xi’an Technological UniversityXi’an 710021China

How to improve the efficiency of exact learning of the Bayesian network structure is a challenging *** this paper,four different causal constraints algorithms are added into score calculations to prune possible parent sets,improving state-ofthe-art learning algorithms’*** results indicate that exact learning algorithms can significantly improve the efficiency with only a slight loss of *** causal constraints,these exact learning algorithms can prune about 70%possible parent sets and reduce about 60%running time while only losing no more than 2%accuracy on ***,with sufficient samples,exact learning algorithms with causal constraints can also obtain the optimal *** general,adding max-min parents and children constraints has better results in terms of efficiency and accuracy among these four causal constraints algorithms.

关键词： Bayesian network structure learning exact learning algorithm causal constraint

Cracking and buoyancy effect on hydrocarbon endothermic and heat transfer characteristics in rectangular mini-channel

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Chinese Journal of Chemical Engineering 2023年第4期56卷 242-254页

作者： Chengang Yang Huaizhi Han Quan Zhu xiangyuan Li School of Chemical Engineering Sichuan UniversityChengdu 610065China Engineering Research Center of Combustion and Cooling for Aerospace Power Ministry of EducationSichuan UniversityChengdu 610065China

Although buoyancy and cracking reactions are strongly coupled in the active cooling process, most of the previous studies consider only one of these factors, and their coupling relationship has not been considerably examined. In this work, this coupling relationship was numerically investigated with complete consideration of different cases of heating, and in the view of energy transport and conversion. By comparing with the no-gravity case(NGC), the results indicate that buoyancy has a significant effect on the bottom-heated case(BHC) and side-heated case(SHC), but has little influence on the top-heated case(THC) owing to the different magnitudes of secondary flow. The heat transfer of the BHC and SHC was significantly enhanced by the secondary flow, but their energy conversion was simultaneously *** conversion of the BHC and SHC was approximately half that of the THC and NGC. For all cases, by analyzing the energy transport ways, the cross section can be classified into three regions in the heating direction. Laminar conduction dominates in region Ⅰ, but gradually fails in region Ⅱ, where its role is replaced by other energy transport ways. In region Ⅲ, convection dominates the energy transport for BHC and SHC, whereas turbulence dominates for THC and NGC.

关键词： Heat transfer Computational fluid dynamics(CFD) buoyancy Hydrocarbons

Structural editing of layered transition metal carbides via chemical scissor-mediated intercalation

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Science China Materials 2023年第6期66卷 2525-2526页

作者： xiangyuan Kong Congwei Tan Hailin Peng School of Physical Science and Engineering Beijing Jiaotong UniversityBeijing 100044China College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China

Intercalation chemistry is a promising methodology that has been widely used to synthesize two-dimensional(2D) materials and their intercalated layered derivatives,predominantly through introducing non-native species into the van der Waals(vdW) *** tailoring guest-host interaction chemistry,the intercalated materials with tunable properties hold promise for fundamental studies of novel physical phenomena and applications ranging from transistors to supercapacitors,batteries,and sensors[1].

关键词： layered chemistry introducing

Generalized flyby trajectories around elongated minor celestial bodies as a rotating mass dipole

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Acta Mechanica Sinica 2016年第3期32卷 535-545页

作者： xiangyuan Zeng Baodong Fang Junfeng Li Yang Yu School of Aerospace Engineering Tsinghua UniversityBeijing 100084 China Shanghai Satellite Engineering Research Institute Shanghai 200240 China Observatoire de la Cote d'Azur 06300 Nice France

The aim of this paper is to understand the common characteristics of the generalized flyby trajectory around natural elongated bodies. Such flyby trajectories provide a short-term mechanism to clear away vicinal objects or temporally capture ejecta into circling orbits. The gravitational potential of elongated bodies is described by a unified approximate model, i.e., the rotating mass dipole which is two point masses connected with a constant massless rod The energy power is used to illustrate the flyby effect in terms of the instantaneous orbital energy. The essential of the single flyby trajectory is studied analytically, and the relationship between the flyby trajectory and its Jacobi integral is also illustrated. Sample trajectories are given to show the variational trend of the energy increment with respect to differen orbital periapsides. The distribution of natural ejecting orbits is presented by varying the parameters of the approximate model.

关键词： Generalized flyby trajectory Natural elongated body Rotating mass dipole Natural ejecting orbits

Experimental Study of Flow Patterns and Improved Configurations for Pulsating Heat Pipes

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Journal of Thermal Science 2007年第1期16卷 56-62页

作者： Shi LIU Jingtao LI xiangyuan DONG Huanzhuo CHEN Institute of Engineering Thermophysics Chinese Academy of Sciences EO. Box 2706 Beijing 100080 China

A series of experiments were performed on three types of closed loop pulsating heat pipes （PHPs）, intending to investigate various kinds of flow patterns, and to develop some improved configurations for the PHPs. Optical visualization results indicated that there might exist three flow patterns, i.e. bubble-liquid slug flow, semi-annular flow and annular flow, corresponding to different working conditions. For a given geometry and an adequate fill ratio, the PHPs had the self-adjusting characteristic for the flow patterns （from slug flow to semi-annular and then to annular flow） to meet the demands of the increasing heat input. Two special configurations, one with alternately varying channel diameter, the other equipped with one section of thicker tube, were found to be advantageous in establishing and maintaining reliable circulation of the working fluid. The thermal performance of the PHPs was examined over a range of working conditions. Comparing with the normal PHP with uniform diameter, either of the improved PHPs exhibited higher thermal performance.

关键词： pulsating heat pipe flow patterns improved configurations.