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Building Simulation 2024年第4期17卷 639-655页

作者： Shanshuo xing Jili Zhang Song Mu Dalian University of technology Dalian116024China Guangdong Airport Baiyun Information technology Co. Ltd.Guangzhou510000China

Optimization for the multi-chiller system is an indispensable approach for the operation of highly efficient chiller *** optima obtained by model-based optimization algorithms are dependent on precise and solvable objective *** classical neural networks cannot provide convex input-output mappings despite capturing impressive nonlinear fitting capabilities,resulting in a reduction in the robustness of model-based *** this paper,we leverage the input convex neural networks(ICNN)to identify the chiller model to construct a convex mapping between control variables and the objective function,which enables the NN-based OCL as a convex optimization problem and apply it to multi-chiller optimization for optimal chiller loading(OCL).Approximation performances are evaluated through a four-model comparison based on an experimental data set,and the statistical results show that,on the premise of retaining prior convexities,the proposed model depicts excellent approximation power for the data set,especially the unseen ***,the ICNN model is applied to a typical OCL problem for a multi-chiller system and combined with three types of optimization *** with conventional and meta-heuristic methods,the numerical results suggest that the gradient-based BFGS algorithm provides better energy-saving ratios facing consecutive cooling load inputs and an impressive convergence speed.

关键词： chiller plant input convex neural network optimal load distribution convex optimization

A BETTER DIFFERENCE SCHEME WITH FOUR NEAR-CONSERVED QUANTITIES FOR THE KdV EQUATION

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Journal of Computational Mathematics 1994年第3期12卷 224-234页

作者： Han Zhen (Computing Center Academia Sinica beijing china)Shen Long-jun(institute of applied physics and Computational Mathematics, beijing, china) 中科院计算数学与科学工程计算所北京北京应用物理和计算数学所北京

In this paper, we present a new semi-discrete difference scheme for the KdV equation, which possesses the first four nearconserved quatities. The scheme is better than the past one given in [4], because its solution ... 详细信息

关键词： KdV A BETTER DIFFERENCE SCHEME WITH FOUR NEAR-CONSERVED QUANTITIES FOR THE KdV EQUATION EH

Prevalence of Cannabis Use around the World:A Systematic Review and Meta-Analysis,2000-2024

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china CDC weekly 2024年第25期6卷 597-604,I0013,I0014页

作者： Qianning Wang Zhen Qin xing xing He Zhu Zhongwei Jia National institute of Health Data Science Center for Drug Abuse Prevention and ControlPeking UniversityBeijingChina School of Public Health Peking UniversityBeijingChina

This study aims to perform a systematic review and meta-analysis on the global prevalence of cannabis use to inform drug prevention strategies,policy-making,and resource *** study initially screened 177,843 studies published between January 1,2000,and January 15,2024,using peer-reviewed databases including Web of Science,PubMed,Scopus,Embase,and Cochrane ***,595 studies were identified for data extraction,and 39 of these were selected as country-representative *** among the selected studies was assessed using the chi-squared test and I2 statistic,while sensitivity analysis was conducted to evaluate the robustness of the *** prevalence of cannabis use varied between 0.42%and 43.90%across 33 European countries,1.40%to 38.12%across 15 North and South American countries,0.30%to 19.10%across 16 Asian countries,and 1.30%to 48.70%across 18 Oceania and African *** pooled prevalence of cannabis use was 12.0%[95%confidence interval(CI):10.0,14.3]in countries where cannabis is legalized,compared to 5.4%(95%CI:4.3,6.9)in non-legalized *** findings indicate that the prevalence of cannabis use has disproportionately increased in most countries with the implementation of medical or recreational cannabis legalization policies and relevant geographic *** efforts are needed to monitor newly cannabis-legalized countries and prevent initial use.

关键词： prevention legal initially

Friction and wear properties of copper matrix composites reinforced by tungsten-coated carbon nanotubes

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Rare Metals 2011年第6期30卷 657-663页

作者： NIE Junhui JIA Xian JIA Chengchang LI Yi ZHANG Yafeng SHI Na School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China china Iron ＆ Steel Research institute Group Beijing 100081 China Journals Publishing Center University of Science and Technology Beijing Beijing 100083 China

Carbon nanotubes （CNTs） were coated by tungsten layer using metal organic chemical vapor deposition process with tungsten hexacarbonyl as a precursor. The W-coated CNTs （W-CNTs） were dispersed into Cu powders by magnetic stirring process and then the mixed powders were consolidated by spark plasma sintering to fabricate W-CNTs/Cu composites. The CNTs/Cu composites were fabricated using the similafprocesses. The friction coefficient and mass wear loss of W-CNTs/Cu and CNTs/Cu composites were studied. The results showed that the W-CNT content, interfacial bonding situation, and applied load could influence the friction coefficient and wear loss of W-CNTs/Cu com- posites. When the W-CNT content was 1.0 wt.%, the W-CNTs/Cu composites got the minimum friction coefficient and wear loss, which were decreased by 72.1% and 47.6%, respectively, compared with pure Cu specimen. The friction coefficient and wear loss of W-CNTs/Cu composites were lower than those of CNTs/Cu composites, which was due to that the interracial bonding at （W-CNTs）-Cu interface was better than that at CNTs-Cu interface. The friction coefficient of composites did not vary obviously with increasing applied load, while the wear loss of composites increased significantly with the increase of applied load.

关键词： carbon nanotubes tungsten layer copper friction coefficient wear loss

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类铍BⅡ离子激发态的相对论能量和精细结构

物理学报 2001年第9期50卷 1681-1684页

作者：韩利红苟秉聪王菲北京理工大学应用物理系北京100081

利用多组态相互作用方法及Rayleigh Ritz变分法 ,计算了类铍BⅡ 1s2 2s2 1 S ,1s2 2s2p1 Po,1s2 2s2p3Po 和 1s2 2p2 3 P激发态的能量 .运用截断变分方法得到能量的改进量 .计算了相对论修正、质量极化效应 ,从而获得了高精度的能量计算... 详细信息

利用多组态相互作用方法及Rayleigh Ritz变分法 ,计算了类铍BⅡ 1s2 2s2 1 S ,1s2 2s2p1 Po,1s2 2s2p3Po 和 1s2 2p2 3 P激发态的能量 .运用截断变分方法得到能量的改进量 .计算了相对论修正、质量极化效应 ,从而获得了高精度的能量计算值 .同时还计算了精细结构、辐射跃迁波长、振子强度、和辐射跃迁率 .计算结果与实验符合得很好 .

关键词：类铍离子精细结构振子强度辐射跃迁相对论能量激发态截断变分法相对论修正质量极化效应复杂电子系统

Finite Dimensional Behavior of Global Attractors for Weakly Damping Ginzburg-Landau Equations Coupling with BBM Equations

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Communications in Nonlinear Science and Numerical Simulation 1998年第1期3卷 10-14页

作者： Boling GUO * and Murong JIANG + *(institute of applied physics and Computational Mathematics,beijing,100088,china) +(Department of Mathematics,Yunnan University,Kunming 650091,china) E mail:guobl@*** Inst. Appl. Phys. and Compl. Math. Beijing 100088 China Department of Mathematics Yunnan University Kunming 650091 China

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关键词： dimension attractor Ginzburg Landau equation couped BBM equationIntroduction

Lie symmetries of mechanical systems with unilateral holonomic constraints

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Chinese Science Bulletin 2000年第15期45卷 1354-1358页

作者： ZHANG Yi & MEI Fengxiang1. Department of Basic Courses, Suzhou institute of Urban Construction & Environmental Protection, Suzhou 215011, china 2. Department of applied Mechanics, beijing institute of technology, beijing 10008I, china Department of Basic Courses Suzhou Institute of Urban Construction & Environmental Protection Suzhou China Department of applied Mechanics Beijing Institute of Technology Beijing China

In the recent twenty years, the study on the Lie symmetries and conserved quantities of constrained mechanical systems has been making great progress[1-5]. Up to now, however, all the studies are limited to the mechanical systems with ideal bilateral constraints. This note further studies the Lie symmetries of mechanical systems with unilateral holonomic constraints, and two problems of Lie symmetries for the systems are put forward and solved, i.e. finding the conserved quantity from a Lie symmetric transformation of the system and finding the corresponding Liesymmetry from an integral of the systemi ? 梛 ? Jsymmetry from an integral of the system.

关键词： analytical mechanics unilateral constraint holonomic system Lie symmetry conserved quantity.

H~m convergence rates of solutions of GBBM equations in multi-dimensional spaces

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Progress in Natural Science:Materials International 2009年第9期19卷 1053-1057页

作者： Shaomei Fang a,*, Boling Guo b a Department of Mathematics, South china Agricultural University, Guangzhou 510642, china b institute of applied physics and Computational Mathematics, beijing 100088, china Department of Mathematics South China Agricultural University Guangzhou 510642 China institute of applied physics and Computational Mathematics Beijing 100088 China

In this paper, we study the decay rates of the generalized Benjamin-Bona-Mahony equations in n-dimensional space. By using Fourier analysis for long wave and by applying the energy method for short wave, we obtain the Hm convergence rates of the solutions when the initial data are in the bounded subset of the phase space HmeRnTen P 3T. The optimal decay rates are obtained in our results and are found to be the same as the Heat equation.

关键词： Generalized Benjamin–Bona–Mahony equations Fourier analysis Energy method Optimal convergence rates

Existence of periodic solutions of the generalized Ginzburg-Landau equation with periodic boundary condition

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Communications in Nonlinear Science and Numerical Simulation 2000年第2期5卷 69-73页

作者： Boling GUO and Rong YUAN (institute of applied physics and Computattonal Mathematics, beijing 100088, china, e-mail: gbl@mail. iapcm. ac. Cn institute of applied physics and Computational Mathematics Beijing 100088 China

In this paper, we study the periodic solution of the generalized Ginzburg-Landau equation by Galerkin method. We show the existence of periodic solution of this equation under appropriate conditions.

关键词： generalized Ginzburg-Landau equation Galerkin method periodic solution

Security Research on Engineering Database System

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厦门大学学报（自然科学版） 2002年第S1期41卷 288-289页

作者： REN Jian-ping 1,2, SONG Han-tao 2, LIANG Yun-rong 2 (1. North china institute of technology, Taiyuan 030051, china 2. beijing institute of technology, beijing 100081, china)

Engine engineering database system is an oriented C AD applied database management system that has the capability managing distributed data. The paper discusses the security issue of the engine engineering database management system (EDBMS). Through studying and analyzing the database security, to draw a series of securi ty rules, which reach B1, level security standard. Which includes discretionary access control (DAC), mandatory access control (MAC) and audit. The EDBMS implem ents functions of DAC, MAC and multigranularity audit. DAC solves the problems o f role inheritance, right contain, authorization identify and cascade revoke, et c; MAC includes subject and object security setup rule, security modify rule and multilevel relation access operation rule, etc; Audit allows making the sub ject, object or operation type as different audit object to implement flexible a nd multigranularity audit method. The model is designed act as a security agent to access daemon database. At present, the model is implemented which runs on th e Windows 2000 environments.

关键词： engineering database management system (EDBMS) s ecurity agent security level