检索结果-南通市图书馆

Optimization for the structure of BF hearth bottom and the arrangement of thermal couples

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2006年第6期13卷 497-503页

作者： Hongbo zhao Shusen cheng Metallurgical and Ecological Engineering School University of Science and Technology Beijing Beijing 100083 China

The hearth of ＂heat transfer method＂ and the ceramic cup synthetic hearth bottom of ＂heart isolation method＂ are two most popular designs for blast furnace （BF）. Although there are successful real examples, some disadvantages, for instance large heat loss and high cost, still exist for these designs. According to the theory of heat transfer, based on the calculation of temperature distribution of the hearth bottom, it is elucidated that all brick layers at the hearth bottom may not be considered as the only reason why different structures exhibited different temperature distributions although total heat resistance is the same, and then based on the effect of hot metal and cold water on different temperature distribution ranges, the concepts of ＂heat resistance＂ and ＂cooling enhancement＂ are put forth. Based on this, the disadvantages and the factors affecting temperature distribution, of the two types of hearth bottoms were illustrated. On the basis of these analyses, a novel structure for BF hearth bottom designing that can easily form ＂self-protecting＂ slag layer stably, called ＂the method of gradient brick layout that has an optimum combination of cooling enhancement and heat resistance＂ was proposed; it can not only prolong the hearth bottom longevity but also reduce the cost and heat loss. Also, the optimum arrangement of thermal couples in hearth bottom was suggested based on the previous studies on erosion prediction carried out by the author.

关键词： blast furnace hearth bottom longevity design erosion

PID controller design for second order nonlinear uncertain systems

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2017年第2期60卷 5-17页

作者： cheng zhao Lei GUO Institute of Systems Science Academy of Mathematics and Systems Science (AMSS)Chinese Academy of Sciences

Although the classical PID(proportional-integral-derivative) controller is most widely and successfully used in engineering systems which are typically nonlinear with various uncertainties, almost all the existing investigations on PID controller focus on linear systems. The aim of this paper is to present a theory on PID controller for nonlinear uncertain systems, by giving a simple and analytic design method for the PID parameters together with a mathematic proof for the global stability and asymptotic regulation of the closed-loop control systems. To be specific, we will construct a 3-dimensional manifold within which the three PID parameters can be chosen arbitrarily to globally stabilize a wide class of second order nonlinear uncertain dynamical systems, as long as some knowledge on the upper bound of the derivatives of the nonlinear uncertain function is *** will also try to make the feedback gains as small as possible by investigating the necessity of the manifold from which the PID parameters are chosen, and to establish some necessary and sufficient conditions for global stabilization of several special classes of nonlinear uncertain systems.

关键词： PID controller nonlinear uncertain systems global stability Lyapunov function asymptotic regulation

Combining SVM and CHMM classifiers for porno video recognition

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2012年第3期19卷 100-106页

作者： zhao Zhi-cheng School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China Beijing Key Laboratory of Network System and Network Culture Beijing University of Posts and Telecommunications Beijing 100876 China

Pomo video recognition is important for Intemet content monitoring. In this paper, a novel pomo video recognition method by fusing the audio and video cues is proposed. Firstly, global color and texture features and local scale-invariant feature transform （SIFT） are extracted to train multiple support vector machine （SVM） classifiers for different erotic categories of image frames. And then, two continuous density hidden Markov models （CHMM） are built to recognize porno sounds. Finally, a fusion method based on Bayes rule is employed to combine the classification results by video and audio cues. The experimental results show that our model is better than six state-of-the-art methods.

关键词： pomo video recognition SVM keyframe CHMM audio

Multi-resonator coupled metamaterials for broadband vibration suppression

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2021年第1期42卷 53-64页

作者： Pengcheng zhao Kai ZHANG cheng zhao Zichen DENG School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi’an 710072China

In this study,multi-resonator coupled metamaterials(MRCMs)with local resonators are proposed to obtain the multiple and wide band *** models of the MRCMs are established,and the boundary conditions of the unit cell are obtained with Bloch's *** effects of structural parameters,including the mass of the resonator and the spring stiffness,on the distributions of the band gaps are ***,the frequency domain responses and the time domain responses are calculated for analyzing the structural vibration characteristics and the effects of damping on structural *** results show that the frequency domain response can accurately express the distributions of the band gaps of the MRCMs,and we can increase the number and the width of the band gaps by using the MRCMs for the superior vibration suppression capability.

关键词： multi-resonator coupled metamaterial(MRCM) band gap broadband vibration suppression

Trusted Attestation Architecture on an Infrastructure-as-a-Service

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2017年第5期22卷 469-477页

作者： Xin Jin Xingshu Chen cheng zhao Dandan zhao the College of Computer Science Sichuan University

Trusted attestation is the main obstruction preventing large-scale promotion of cloud computing. How to extend a trusted relationship from a single physical node to an Infrastructure-as-a-Service （laaS） platform is a problem that must be solved. The laaS platform provides the Virtual Machine （VM）, and the Trusted VM, equipped with a virtual Trusted Platform Module （vTPM）, is the foundation of the trusted laaS platform. We propose a multi-dimensional trusted attestation architecture that can collect and verify trusted attestation information from the computing nodes, and manage the information centrally on a cloud management platform. The architecture verifies the laaS＇s trusted attestation by apprising the VM, Hypervisor, and host Operating System＇s （OS） trusted status. The theory and the technology roadmap were introduced, and the key technologies were analyzed. The key technologies include dynamic measurement of the Hypervisor at the process level, the protection of vTPM instances, the reinforcement of Hypervisor security, and the verification of the laaS trusted attestation. A prototype was deployed to verify the feasibility of the system. The advantages of the prototype system were compared with the Open CIT （Intel Cloud attestation solution）. A performance analysis experiment was performed on computing nodes and the results show that the performance loss is within an acceptable range.

关键词： dynamic measurement trusted cloud vTPM trusted attestation

Controlled rocking pile foundation system with replaceable bar fuses for seismic resilience

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2022年第3期21卷 683-696页

作者： cheng zhao Li Shuai Wang Jingquan Bridge Engineering Research Center of Southeast University School of Civil EngineeringSoutheast UniversityNanjing 210096China

Bridges designed following a conventional approach minimize the risk of collapse,but often require challenging,costly,and time-consuming restoration after an earthquake *** new seismic design philosophy requires bridges to maintain functionality even after severe *** this context,this paper proposes a controlled rocking pile foundation(CRPF)system and numerically evaluates bridges′degree of seismic *** CRPF system allows a pile cap to rock on a pile foundation and dissipate seismic energy through inelastic deformations of replaceable bar fuses that connect a pile cap and *** the conceptual design of the CRPF system,two analytical models were developed for a bridge pier utilizing the CRPF system and a pier designed to develop a plastic hinge in its *** analytical results indicate that,after experiencing a severe earthquake,a conventionally designed bridge pier sustained substantial damage in its column and exhibited significant residual *** contrast,a pier using the CRPF system showed negligible residual displacement and maintained elastic behavior except,as expected,for bar *** damaged fuses can be rapidly replaced to recover bridge seismic resistance following an ***,the CRPF system helps to achieve the desired postearthquake performance objectives.

关键词： seismic resilience bridges pier controlled rocking pile foundation repairable bar fuse

干湿循环下再生混凝土氯离子传输行为的细观模拟

在线全文

学校读者我要写书评

暂无评论

科学技术与工程 2025年第1期25卷 329-338页

作者：白希选陆定洋赵程王桥武汉工程大学土木工程与建筑学院武汉430074 武汉大学水利水电学院武汉430072

基于蒙特卡洛法,利用Python与Abaqus接口进行二次开发,生成区分天然粗骨料,新、旧界面过渡区(interfacial tran-sition zone,ITZ)和新、旧砂浆的再生混凝土(recycled aggregate concrete,RAC)二维细观五相模型。提出改进的干湿循环下水... 详细信息

基于蒙特卡洛法,利用Python与Abaqus接口进行二次开发,生成区分天然粗骨料,新、旧界面过渡区(interfacial tran-sition zone,ITZ)和新、旧砂浆的再生混凝土(recycled aggregate concrete,RAC)二维细观五相模型。提出改进的干湿循环下水分-氯离子耦合模型,并将该模型的计算结果与物理试验进行对比验证,结果吻合较好。将该模型应用于分析干湿循环周期、ITZ渗透率、水胶比和天然骨料体积分数对氯离子传输性能的影响规律。结果表明,在干湿循环次数增加的情况下,RAC中氯离子的扩散深度和浓度也会随之增加。当ITZ扩散系数与新砂浆扩散系数的比值增大时,氯离子的扩散区域中氯离子浓度增加明显,尤其是在扩散区的前端位置氯离子浓度增加最为显著。此外,不同水灰比的RAC材料与氯离子的传输能力之间存在正相关关系,高水灰比范围内氯离子传输性能变化较小。最后,再生骨料体积分数对RAC的抗氯离子渗透性能产生显著影响,这说明ITZ和新旧砂浆对氯离子的传输具有重要影响。

关键词：再生混凝土细观数值模型干湿循环水分氯离子传输过程

Uncoupled PID Control of Coupled Multi-Agent Nonlinear Uncertain Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2018年第1期31卷 4-21页

作者： YUAN Shuo zhao cheng GUO Lei LSC Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China. School of Mathematical Sciences University of Chinese Academy of Sciences Beijing 100049 China LSC Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

In this paper, PID（proportional-integral-derivative） controllers will be designed to solve the tracking problem for a class of coupled multi-agent systems, where each agent is described by a second-order high-dimensional nonlinear uncertain dynamical system, which only has access to its own tracking error information and does not need to communicate with others. This paper will show that a 3-dimensional manifold can be constructed based on the information about the Lipschitz constants of the system nonlinear dynamics, such that whenever the three parameters of each PID controller are chosen from the manifold, the whole multi-agent system can be stabilized globally and the tracking error of each agent approaches to zero asymptotically. For a class of coupled first-order multi-agent nonlinear uncertain systems, a PI controller will be designed to stabilize the whole system.

关键词： Coupled multi-agent system global stability Lipschitz condition nonlinear uncertain dynamics PID controller

High-throughput experimental tools for the materials genome initiative

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2014年第15期59卷 1652-1661页

作者： Ji-cheng zhao Department of Materials Science and Engineering The Ohio State University State Key Laboratory of Powder Metallurgy Central South University

The materials innovation infrastructure in the materials genome initiative(MGI)consists of three major components:computational tools,experimental tools,and digital *** article will review experimental tools for high-throughput,high spatial resolution measurements of several materials properties such as elastic modulus,thermal conductivity,specific heat capacity,and thermal *** of these tools on compositionvarying samples such as diffusion multiples can be used to quickly and efficiently obtain composition–phase–structure–property relationships for materials property database *** can also be used in conjunction with theoretical modeling to find and explain unusual effects to improve the predictability of *** micron scale resolution experimental tools are in *** high-throughput tools will be an essential part of MGI.

关键词：计算工具材料性能基因组计划高通量实验高空间分辨率属性数据库组成部分