检索结果-南通市图书馆

Stability Investigation and Improvement for DC Cascade Systems with Simplified Impedance-based Stability Criterion

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

CSEE Journal of Power and Energy Systems 2024年第3期10卷 1044-1052页

作者： Junbin Fang Zhikang Shuai Yang Li zhibing wang Xiangyang Wu Xia Shen Z.John Shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Renewable Energy Department of China Electric Power Research Institute Beijing 100192China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA IEEE

In DC distributed power systems(DPSs),the complex impedance interactions possibly lead to DC bus voltage oscillation or *** previous research,the stability analysis of DPSs is implemented based on mathematical analysis in control *** specific mechanisms of the instability of the cascade system have not been intuitively *** this paper,the stability analysis of DPSs based on the traditional Nyquist criterion is simplified to the resonance analysis of the seriesconnected port impedance(Z=R+jX)of source and load *** reveals that the essential reason for impedance instability of a DC cascade system is that the negative damping characteristic(R<0)of the port the overall impedance amplifies the internal resonance source at reactance zero-crossing *** simplified stability criterion for DC cascade systems can be concluded as:in the negative damping frequency ranges(R<0),there exists no zero-crossing point of the reactance component(i.e.,X=0).According to the proposed stability criterion,the oscillation modes of cascade systems are classified.A typical one is the internal impedance instability excited by the negative damping,and the other one is that the external disturbance amplified by negativity in a low stability ***,the impedance reshaping method for stability improvement of the system can be further *** validity of the simplified criterion is verified theoretically and experimentally by a positive damping reshaping method.

关键词： DC cascaded system,impedance model impedance reconstruction stability criterion

Key technologies for medium and low voltage DC distribution system

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

Global Energy Interconnection 2021年第1期4卷 91-103页

作者： Yiwen Fan Yongning Chi Yan Li zhibing wang Hongzhi Liu Wei Liu Xiangyu Li China Electric Power Research Institute Beijing 100192P.R.China College of Electrical and Electronic Engineering North China Electric Power UniversityBeijing 102206P.R.China School of Engineering Cardiff UniversityCF243AAUK

Development of the medium and low voltage DC distribution system is of great significance to a regional transmission of electric energy,increasing a penetration rate of new energy,and enhancing a safety of the operation of the AC/DC interconnected *** paper first summarizes the medium and low voltage DC distribution system schemes and plans put forward by many countries,and then elaborate status of under-construction medium and low voltage DC distribution system project cases in *** on these project cases,this paper analyzes key issues involved in the medium and low voltage DC distribution system topologies,equipment,operation control technologies and DC fault protections,in order to provide theoretical and technical reference for future medium and low voltage DC distribution system-related ***,this paper combines a current China research status to summarize and give a prediction about the future research direction of medium and low voltage DC distribution system,which can provide reference for the research of medium and low voltage DC distribution system.

关键词： Medium and low voltage DC distribution system System topology Key equipment DC fault protection Operation control technology

Space qualification mechanical tests of HTS filters for satellite application

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2007年第13期52卷 1771-1775页

作者： HUANG JianDong SUN Liang LI ShunZhou MENG QingDuan ZHANG Qiang LI Fei ZHANG XueQiang LI ChunGuang HE AiSheng LI Hong GU ChangZhi LUO Qiang SUN QinFen wang XiaoLin SUN YiFan wang zhibing wang YunFei LUO Sheng HE YuSheng Institute of Physics Chinese Academy of Sciences and Beijing National Laboratory of Condensed Matter Physics Beijing 100080 China Institute of Physics Chinese Academy of Sciences and Beijing National Laboratory of Condensed Matter Physics Beijing 100080 China Institute of Physics Chinese Academy of Sciences and Beijing National Laboratory of Condensed Matter Physics Beijing 100080 China Institute of Physics Chinese Academy of Sciences and Beijing National Laboratory of Condensed Matter Physics Beijing 100080 China Institute of Physics Chinese Academy of Sciences and Beijing National Laboratory of Condensed Matter Physics Beijing 100080 China Xi'an Institute of Space Radio Technology Xi'an 710000 China Xi'an Institute of Space Radio Technology Xi'an 710000 China Xi'an Institute of Space Radio Technology Xi'an 710000 China Xi'an Institute of Space Radio Technology Xi'an 710000 China Xi'an Institute of Space Radio Technology Xi'an 710000 China Institute of Acoustics Chinese AcademY of Sciences Beijing 100080 China Department of Physics University of Science and Technology Beijing Beijing 100083 China

High performance high-temperature superconducting (HTS) filters have been designed and constructed for satellite application. The filters are actually a superconducting integration of an 8-pole band-pass filter with an adjustable band-stop filter onto a single piece of LaAlO3 substrate (with dimension of 0.5×45×20 mm3). Typical results of the filters, i.e., Filters A (made by YBCO) & B (made by TBCCO) will be reported. The measured responses of Filter A showed excellent specifications, e.g., an insertion loss less than 0.1 dB, a return loss better than -22.5 dB in pass-band, band-edge steepness greater than 12 dB/MHz and out-of-band rejection at a certain band deeper than -110 dB. To satisfy the requirement of rocket launch and space operation, three filters of the above design have undergone mechanical environmental simulation tests for space qualification. Detailed analysis of the response curves of Filter B measured before and after the tests showed that no noticeable change in the per-formance can be found. All the filters passed the rigorous ground simulation tests, which is the first time in China for HTS devices and provided a solid foundation for satellite applications of high-temperature superconductors in the near future.

关键词：超导体滤波器空间条件实验温度

在线全文

学校读者我要写书评

暂无评论

民国职业学校出品展览会概况述论

职业技术教育 2015年第15期36卷 65-71页

作者：王志兵江苏商贸职业学院院长助理兼党政办南通226011

民国时期,为展示职业教育成果,扩大社会影响和吸引力,提升职业学校的办学水平,加强职业学校间的交流、学习和借鉴,政府和职业教育界以举办职业学校出品展览会为平台和载体,力求推动职业教育面向社会生产生活需求进行研究和改进,使职业... 详细信息

民国时期,为展示职业教育成果,扩大社会影响和吸引力,提升职业学校的办学水平,加强职业学校间的交流、学习和借鉴,政府和职业教育界以举办职业学校出品展览会为平台和载体,力求推动职业教育面向社会生产生活需求进行研究和改进,使职业教育更具现实应用性和针对性,以突出职业教育服务社会经济发展的作用。然而,由于社会动荡,展览会举办时断时续。回顾民国时期职业学校出品展览会,发现其存在政府及教育行政部门对展览会不够重视,展览会实际成效不明显,展览会成果与职业教育的现实状况差距较大,职业学校参与面不广等主要问题。这对当今职业教育的内涵建设与发展有所启示。

关键词：民国职业学校出品展览会

民国职业学校经费政策措施演进及存在问题考述

在线全文

学校读者我要写书评

暂无评论

职业技术教育 2023年第12期44卷 73-80页

作者：王志兵江苏商贸职业学院纪委南通226011 江苏商贸职业学院纪委办南通226011

办好职业教育,必须有充足的经费作为根本保障,最重要的是政府主体性作用的发挥。民国职业学校的经费主要包括开办设立的经费、学校日常经费、教职员工薪酬奖励、教学实习设备投入和学生的补助奖励等。基于经济社会发展对职业教育的现实... 详细信息

办好职业教育,必须有充足的经费作为根本保障,最重要的是政府主体性作用的发挥。民国职业学校的经费主要包括开办设立的经费、学校日常经费、教职员工薪酬奖励、教学实习设备投入和学生的补助奖励等。基于经济社会发展对职业教育的现实需求,民国政府、教育行政部门制定了一系列职业教育经费的政策措施,给予职业教育经费的倾斜和扶持,力求职业学校在量、质上的提升发展。但由于政策的非连续性,缺乏整体的系统化构建,以及落实过程中的非到位性和社会发展多重矛盾、问题的积重难返,使得职业学校在办学过程中,一直受到经费来源的困扰,导致职业学校发展处于不稳定的状态,职业教育整体质量难以精进。

关键词：民国职业学校教育经费政策演进

在线全文

学校读者我要写书评

暂无评论

民国初期商科职业教育变革思想与实践考述

职业技术教育 2021年第6期42卷 73-79页

作者：王志兵江苏商贸职业学院纪委南通226011

受西方职业教育兴起和发展的影响,清末民初"实业教育"逐步向"职业教育"转型,其中,与经济社会密切相关、适用范围广泛的商科教育成为重点。实业教育阶段,商科教育体制陈旧、教学脱离实践、课程设置不合理等问题突显,影响了商业人才的培养... 详细信息

受西方职业教育兴起和发展的影响,清末民初"实业教育"逐步向"职业教育"转型,其中,与经济社会密切相关、适用范围广泛的商科教育成为重点。实业教育阶段,商科教育体制陈旧、教学脱离实践、课程设置不合理等问题突显,影响了商业人才的培养,阻碍了社会经济的发展。民国初期教育界、商业界团体和有识之士,以强烈的忧民情怀、为民大爱和社会责任感,不断推动商科职业教育的改革发展,在明确培养目标,理论与实际并重,改革教学模式,强化课外训练,注重教材建设,开展与商界合作,实施商业补习、传习教育等方面,进行了实践探索,为促进社会经济发展作出了贡献。

关键词：民国初期商科职业教育商学合作

在线全文

学校读者我要写书评

暂无评论

高职院校混合所有制改革的逻辑、政策与内涵

教育与职业 2019年第8期 5-11页

作者：王志兵江苏商贸职业学院

高职院校混合所有制改革是深入推进办学模式的体制机制创新,落实"深化产教融合、校企合作"的重要载体。只有全面理解国家政策内涵,准确掌握政策导向,明晰混合所有制改革的主体对象、厘清四种实现形式、把握投入要素和定位,形成参与各方... 详细信息

高职院校混合所有制改革是深入推进办学模式的体制机制创新,落实"深化产教融合、校企合作"的重要载体。只有全面理解国家政策内涵,准确掌握政策导向,明晰混合所有制改革的主体对象、厘清四种实现形式、把握投入要素和定位,形成参与各方相互的认同、理念的相同、目标的趋同、行动的协同、责任的共同,才能探索出高职院校混合所有制改革的成功发展之路。

关键词：高职院校混合所有制逻辑内涵

在线全文

学校读者我要写书评

暂无评论

壬戌学制确定过程中职业教育地位确立研究

职业技术教育 2021年第36期42卷 73-80页

作者：王志兵江苏商贸职业学院纪委南通226011 江苏商贸职业学院纪委办南通226011

1922年北洋政府实施壬戌学制,职业教育作为民国教育体系中的一种教育类型,确立了法律上的地位。在壬戌学制的提出、起草、议决和实施过程中,以全国性民间教育组织全国省教育会联合会、中华职业教育社等为首的教育团体,各类学校及民国教... 详细信息

1922年北洋政府实施壬戌学制,职业教育作为民国教育体系中的一种教育类型,确立了法律上的地位。在壬戌学制的提出、起草、议决和实施过程中,以全国性民间教育组织全国省教育会联合会、中华职业教育社等为首的教育团体,各类学校及民国教育界的有识之士,不遗余力地大力推进,特别对职业教育体系在壬戌学制中的设置进行了全面、深入、广泛的讨论,推动了职业教育在壬戌学制中的地位确立,成就了中国教育史上一场自下而上的革命性教育改革,打破了千百年以来封建陈腐教育思想的桎梏,完善了民国的教育体系,为实现经济社会发展、满足人的职业发展需求作出了积极的贡献。

关键词：壬戌学制职业教育体系地位学制

Off-pump Coronary Endarterectomy and Bypass Grafting in Patients With Diffuse Coronary Artery Disease

在线全文

学校读者我要写书评

暂无评论

South China Journal of Cardiology 2006年第2期7卷 104-107,72页

作者： Chen Xin Xu Ming Jiang Yinshuo Sui Kaihu Qiu zhibing wang Liming Liu Peisheng Department of Thoracic and Cardiovascular Surgery Nanjing First HospitalNanjing Heart Institute Nanjing Medical University Nanjing 210006 China

Objectives preliminary experience on endarterectomy and To summarize our off-pump coronary bypass grafting in patients with diffuse coronary artery disease. Methods Over a 3year period, 53 patients （41 male） with diffuse coronary artery disease underwent off-pump coronary endarterectomy and bypass grafting at our institution. Patients＇ age ranged from 55 to 79 years. Prior to surgery, 70% of patients were in CCS angina class 2 （n=5） or 3 （n=32）, and nearly half of them （26/53） had history of myocardial infarction. Most patients （n= 50） had triple vessel lesions, with left main stem involvement in 9. Their left ventricular ejection fraction ranged from 26% to 65% （mean 52%）. At the end of operation, a flow-meter was routinely applied to measure the perfusion flow of each postendarterectomy graft. Results In total, 70 endarterectomies were performed in 53 patients, including 38 in left anterior descending artery （LAD）, 8 in circumflex artery and 24 in right coronary artery. Four operations were emergency or urgent in nature. Five patients received on-lay venous patch after endarterectomy in LAD, followed by left internal mammary artery （LIMA） grafting on the patch. The graft conduits included 53 LIMAs and 2 radial arteries, and saphenous veins in others. Mean number of grafts per patient was 3.75. The overall index of complet-eness of revascularization reached 1.03±0.07. There was no death in this group of patients during their post-operative hospital stay （mean duration = 9 days）. Intra-operatively, 63 （90%） out of the 70 grafts after coronary endarterectomy showed satisfactory flow. Two patients had perioperative neither experienced signifi myocardial infarctions but cant hemodynamic deteriations. Conclusions Off-pump coronary endarterectomy with bypass grafting is technically feasible and can be coronary improve zation. performed safely in patients with diffuse artery disease. This strategy may help to the completeness of myocardial revasculariation.

关键词： Coronary endarterectomy Off-pumpCoronary artery bypass grafting Diffuse coronaryartery disease