检索结果-南通市图书馆

Simplified design of nonlinear damper parameters and seismic responses for long-span cable-stayed bridges with nonlinear viscous dampers

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2024年第7期18卷 1103-1116页

作者： Huihui LI lifeng LI Rui HU Meng ye College of Civil and Transportation Engineering Shenzhen UniversityShenzhen 518060China Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering Shenzhen UniversityShenzhen 518060China College of Civil Engineering Hunan UniversityChangsha 410082China

Viscous dampers are widely used as passive energy dissipation devices for long-span cable-stayed bridges for mitigation of seismic load-induced ***,complicated finite element(FE)modeling,together with repetitive and computationally intensive nonlinear time-history analyses(NTHAs)are generally required in conventional design *** streamline the preliminary design process,this paper developed a simplified longitudinal double degree of freedom model(DDFM)for single and symmetric twin-tower cable-stayed *** on the proposed simplified longitudinal DDFM,the analytical equations for the relevant mass-and stiffness-related parameters and longitudinal natural frequencies of the structure were derived by using analytical and energy *** of the relationship between the nonlinear viscous damper parameters and the equivalent damping ratio was achieved through the equivalent linearization ***,the analytical equations of longitudinal seismic responses for long-span cable-stayed bridges with nonlinear viscous dampers were *** on the developed simplified DDFM and suggested analytical equations,this paper proposed a simplified calculation framework to achieve a simplified design method of nonlinear viscous damper ***,the effectiveness and applicability of the developed simplified longitudinal DDFM and the proposed calculation framework were further validated through numerical analysis of a practical cable-stayed ***,the results indicated the following.1)For the obtained fundamental period and longitudinal stiffness,the differences between results of the simplified longitudinal DDFM and numerical analysis were only 2.05%and 1.5%,respectively.2)Relative calculation errors of the longitudinal girder-end displacement and bending moment of the bottom tower section of the bridge obtained from the simplified longitudinal DDFM were limited to less than 25%.3)The equivalent damping ratio of nonline

关键词： cable-stayed bridges viscous dampers simplified analytical model equivalent damping ratio seismic mitigation

Numerical study on the laser ablative Rayleigh-Taylor instability

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2020年第4期36卷 789-796页

作者： Zhiyuan Li lifeng Wang Junfeng Wu Wenhua ye Institute of Applied Physics and Computational Mathematics Beijing 100094China Center for Applied Physics and Technology HEDPSand College of EngineeringPeking UniversityBeijing 100871China

The laser ablative Rayleigh-Taylor instability plays an important role in the ignition of inertial refinement *** accurate simulation of this process is important to control the growth of flow instability during the *** this paper,taking the simulations of the hydrodynamics,the laser energy deposition and the electronic thermal conductivity into consideration,a massively parallel laser ablative Rayleigh-Taylor instability code based on Euler method is *** open source codes are used to improve the code development *** accuracy of the hydrodynamics simulation is tested by an analytical theory about the weakly nonlinear Rayleigh-Taylor instability with double *** benchmark of an one dimensional heat conductivity is used to test the accuracy of the thermal conductivity *** laser ablative plane target and the laser ablative Rayleigh-Taylor instability are used to test the reliability of the code on the simulation of the whole laser ablative *** is shown that the confidence of our numerical simulation code is high and the code framework we designed is *** can be a basis on studying the problems about the laser ablative instability in inertial refinement fusion.

关键词： Laser ablation Inertial confinement fusion Numerical simulation Rayleigh-Taylor instability

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

智慧水务复杂生产数据安全高效采集方法研究

水利技术监督 2023年第10期 76-81页

作者：叶李锋林高基欧阳军颜野迪毛军辉净化控股集团股份有限公司浙江台州317605 西安财经大学商学院陕西西安710000

传统水厂数据传输基于可编程逻辑控制器(PLC)与上位机组态软件进行通讯。在组态软件中,采用不同网络协议和不同规格型号的PLC导致数据采集和传输方式参差不齐,不仅增加了开发成本,还因数据不一致而互相冲突,导致数据采集错误。文章在大... 详细信息

传统水厂数据传输基于可编程逻辑控制器(PLC)与上位机组态软件进行通讯。在组态软件中,采用不同网络协议和不同规格型号的PLC导致数据采集和传输方式参差不齐,不仅增加了开发成本,还因数据不一致而互相冲突,导致数据采集错误。文章在大量实践基础上,提出采用软硬件结合的方法对水厂复杂自控数据进行实时采集,该方法能够兼容常用组态软件和PLC器件,同时具有安全高效、稳定可靠的优势,为智慧水厂业务应用和分析展示奠定数据基础。

关键词：智慧水厂自控系统 PLC 实时数据采集

在线全文

学校读者我要写书评

暂无评论

面向机器人码垛的输送控制系统设计

自动化应用 2021年第4期 7-9页

作者：褚伟锋叶利峰蒋力李建海杭州娃哈哈精密机械有限公司浙江杭州310018

针对生产线上不同规格箱型产品的码垛需求,设计了基于西门子S7-1200PLC的输送控制系统,搭配工业机器人及真空吸具,实现产品自动整列、栈板输送、机器人码垛、整垛输出等功能。该系统适应范围广、实用性强、效率高,可以满足不同规格箱型... 详细信息

针对生产线上不同规格箱型产品的码垛需求,设计了基于西门子S7-1200PLC的输送控制系统,搭配工业机器人及真空吸具,实现产品自动整列、栈板输送、机器人码垛、整垛输出等功能。该系统适应范围广、实用性强、效率高,可以满足不同规格箱型产品的整列、码垛需求,有效提高码垛效率。

关键词：码垛机器人输送控制系统

在线全文

学校读者我要写书评

暂无评论

辽宁省大葱产业现状及对策

北方园艺 2017年第3期 187-189页

作者：李莉峰叶春苗王丽颖李国东韩艳秋辽宁省农业科学院食品与加工研究所辽宁沈阳110161 辽阳职业技术学院化学工程系辽宁辽阳111000 本溪县农业技术推广中心辽宁本溪117100

从辽宁大葱产业发展现状入手,分析了辽宁大葱产业发展存在的问题:专业化生产技术水平不高;专业人才缺乏,技术服务体系有待加强;地方品种多,适合加工、出口的专用品少;加工技术落后,经济效益低;经营模式落后,品牌效应不足等。针对上述问... 详细信息

从辽宁大葱产业发展现状入手,分析了辽宁大葱产业发展存在的问题:专业化生产技术水平不高;专业人才缺乏,技术服务体系有待加强;地方品种多,适合加工、出口的专用品少;加工技术落后,经济效益低;经营模式落后,品牌效应不足等。针对上述问题,提出辽宁大葱产业发展应采取加强科学研究,培育新品种,研发新产品;推进大葱标准化生产基地建设;发展标准化龙头企业的带头作用,创立地方品牌;开拓营销渠道,建立产业化经营模式;加强大葱标准化体系的建设等措施。

关键词：辽宁大葱现状对策

在线全文

学校读者我要写书评

暂无评论

对氟苯甲醛合成工艺进展

化工生产与技术 2009年第1期16卷 5-7页

作者：叶立峰曾瑜周文军郎利新浙江工业大学杭州310014 国家氟材料工程技术研究中心浙江衢州324004 浙江工业大学浙西分校浙江衢州324000 衢州市环境保护局衢江分局浙江衢州324017

介绍了对氟苯甲醛的基本性质和用途,叙述了几种具有工业意义的对氟苯甲醛合成方法,评述了各法的优缺点,认为对氯苯甲醛氟化法、氟苯甲酰化法工艺简单、收率高、原料价格便宜,是2条具有工业竞争力的合成路线。

关键词：对氟苯甲醛对氯苯甲醛氟苯氟化甲酰化

Atomic structure and enhanced thermostability of a new structure MgYZn4 formed by ordered substitution of Y for Mg in MgZn2 in a Mg-Zn-Y alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第9期35卷 2058-2063页

作者： lifeng Zhang Shangyi Ma Weizhen Wang Zhiqing Yang Hengqiang ye Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesSchool of Materials Science and EngineeringUniversity of Science and Technology of ChinaShenyang110016China School of Materials Science and Engineering Northeastern UniversityShenyang110819China

A new phase MgYZn4 in Mg-Zn-Y alloy was studied using aberration-corrected scanning-transmission electron microscopy and first-principles calculations. Nanometer-sized MgYZn4 precipitates were formed through ordered substitutions of Y with 50% Mg atoms in MgZn2. MgYZn4 has an orthorhombic structure with a space group of Pmnn, and lattice parameters a =5.2965∧, b =9.4886∧, and c =8.5966 ∧. Importantly, both size and structure of MgYZn4 are stable at 625 K for 5 h, showing higher thermostability than MgZn2, which should be important for applications at elevated temperatures. The enhanced thermostability of MgYZn4 is attributed to the lower formation energy and bonding enhancement due to Y substitution.

关键词： MgYZn4 Thermostability Laves phase Precipitate Mg alloys

在线全文

学校读者我要写书评

暂无评论

O-甲基-N-硝基异脲的合成

化工生产与技术 2009年第3期16卷 25-26,29页

作者：曾瑜叶立峰郎利新姚晓艳王彤巨化集团技术中心 324004 衢州市环境保护局衢江分局环境监测站浙江衢州324017

采用O-甲基异脲盐、硝酸和硫酸为原料一步反应生成O-甲基-N-硝基异脲。研究了影响反应收率的各种因素。结果表明,选择O-甲基异脲1/2硫酸盐、发烟硫酸和发烟硝酸作为原料反应较理想,收率可达95%。IR和1HNMR对产品进行了结构鉴定,确定产品... 详细信息

采用O-甲基异脲盐、硝酸和硫酸为原料一步反应生成O-甲基-N-硝基异脲。研究了影响反应收率的各种因素。结果表明,选择O-甲基异脲1/2硫酸盐、发烟硫酸和发烟硝酸作为原料反应较理想,收率可达95%。IR和1HNMR对产品进行了结构鉴定,确定产品为O-甲基-N-硝基异脲。

关键词： O-甲基-N-硝基异脲 O-甲基异脲盐硝酸硫酸合成

Front-end signal analysis of the transverse feedback system for SSRF

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2008年第5期19卷 274-277页

作者： HAN lifeng YUAN Renxian YU Luyang ye Kairong Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China

Multi-bunch instabilities degrade beam quality through increased beam emittance,energy spread and even cause beam loss.A feedback system is used to suppress multi-bunch instabilities associated with resistive wall of the beam ducts,cavity-like structures,and trapped ions.A digital TFS (Transverse Feedback System) is in construction at the SSRF (Shanghai Synchrotron Radiation Facility),which is based on the latest generation of FPGA (Field Programmable Gate Array) *** we get such FPGA disital board,investigation and simulation of the front-end were done in the first *** signal flow was analyzed by *** and optimization of the entire system is our next goal.

关键词：同步加速器前置电路信号分析横向反馈系统