锂离子电池正极材料二巯基噻二唑的研究进展

二巯基噻二唑(DMcT)作为锂离子电池正极材料,具有容量高、寿命长、制备简便等优点,但它在室温下的反应速度较慢.介绍DMcT在锂离子电池中的充放电机理及利用聚苯胺、聚吡咯、聚3,4-乙撑二氧噻吩、聚邻甲基苯胺、聚N-甲基化苯胺、聚3-烷基酯-4-甲基吡咯、聚3-丁基酯-4-甲基吡咯、聚二巯基噻二唑、金属离子以及金属纳米粉等电催化剂对DMcT进行改性的研究进展,以及电催化剂对DMcT电化学性能的影响.通过这些改性,DMcT的放电容量、正极电流、循环寿命都得到了改善.     

Accuracy of short-axis cardiac MRI automatically derived from scout acquisitions in free-breathing and breath-holding modes

To qualitatively assess the accuracy of automated cardiovascular magnetic resonance planning procedures devised from scout acquisitions in free-breathing and breath-holding modes, to quantitatively evaluate the accuracy of the derived left ventricular volumes, mass and function and compare these parameters with the ones obtained from the manually planned acquisitions. Ten healthy volunteers underwent cardiovascular MR (CMR) acquisitions for ventricular function assessment. Short-axis data sets of the left ventricle (LV) were manually planned and generated twice in an automatic fashion. Automated planning parameters were derived from gated scout acquisitions in free-breathing and breath-holding modes. End-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), and left ventricular mass (LVM) were measured. The agreement between the manual and automatic planning methods, as well as the variability of the aforementioned measurements were assessed. The differences between two automated planning methods were also compared. The mean differences between the manual and automated CMR planning derived from gated scouts in free-breathing mode were 8.05 ml (EDV), 1.84 ml (ESV), 0.69% (EF), and 4.72 g (LVM). The comparison between manual and automated CMR planning derived from gated scouts in breath-holding mode yielded the following differences: 4.22 ml (EDV), 0.34 ml (ESV), 0.3% (EF), and –0.72 mg (LVM). The variability coefficients were 3.72 and 3.66 (EDV), 5.6 and 8.19 (ESV), 3.46 and 4.31 (EF), 6.49 and 5.20 (LVM) for the automated CMR planning methods derived from scouts in free-breathing and breath-holding modes, respectively. Automated CMR planning methods can provide accurate measurements of LV dimensions in normal subjects, and therefore may be utilized in the clinical environment to provide a cost-effective solution for functional assessment of the human cardiovascular system.     

用灰色多变量模型预测变压器油中溶解的气体浓度

目前变压器油中气体浓度预测普遍采用GM(1,1)模型及其改进形式,针对其在建模时只单独考虑某种气体发展变化的不足,介绍了灰色多变量预测模型MGM(1,n),它可以综合考虑从同一信号中提取的多个诊断指标,因而预测更科学、有效。对变压器油中溶解的7种特征气体即氢气、甲烷、乙烷、乙烯、乙炔、一氧化碳和二氧化碳进行了灰色关联分析,建立了相应的MGM(1,7)模型,预测实例分析证明,与传统GM(1,1)模型及其改进形式相比,用灰色多变量模型预测的效果更好。     

Simulation of statistical variability in nano-CMOS transistors using drift-diffusion, Monte Carlo and non-equilibrium Green’s function techniques

In this paper, we present models and tools developed and used by the Device Modelling Group at the University of Glasgow to study statistical variability introduced by the discreteness of charge and matter in contemporary and future Nano-CMOS transistors. The models and tools, based on Drift-Diffusion (DD), Monte Carlo (MC) and Non-Equilibrium Green’s Function (NEGF) techniques, are encapsulated in the Glasgow 3D statistical ‘atomistic’ device simulator. The simulator can handle most of the known sources of statistical variability including Random Discrete Dopants (RDD), Line Edge Roughness (LER), Thickness Fluctuations in the Oxide (OTF) and Body (BTF), granularity of the Poly-Silicon (PSG), Metal Gate (MGG) and High-κ (HKG), and oxide trapped charges (OTC). The results of the statistical simulations are verified with respect to measurements carried out on fabricated devices. Predictions about the magnitude of the statistical variability in future generations of nano-CMOS devices are also presented.     

Optimization techniques for string selection and comparison problems in genomics

In this article, a discussion of optimization issues occurring in the area of genomics such as string comparison and selection problems are discussed. With this objective, an important part of the existing results in this area will be discussed. The problems that are of interest in this paper include the closest string problem (CSP), closest substring problem (CSSP), farthest string problem (FSP), farthest substring problem (FSSP), and far from most string (FFMSP) problem. The paper presents a detailed view of the most important problems occurring in the area of string comparison and selection, using the Hamming distance measure is given.     

Book reviews [8 books reviewed}

Books reviewed: Physics of Solar Cells, 2nd Edition (Wurfel, P.; 2009), Essentials of RF and Microwave Grounding (Holtzman, E.; 2006), Polymer Tribology (Sinha, S. K. and Briscoe,B. J.; 2009), PVC Degradation and Stabilization (Wypych, G.; 2008), Advanced Batteries (Huggins, R. A.; 2009), The Lineman's and Cableman's Field Manual, 2nd Edition (Shoemaker, T. M. and Mack, J. E.; 2009), Lead Your Boss (Baldoni, J.; 2009), Industrial Power Systems (Khan, S.; 2008)     

Evaluation of modern power semiconductor devices and future trendsof converters

The author reviews the modern power semiconductor devices that appeared in the 1980s, i.e., the insulated gate bipolar transistor (IGBT), static induction transistor (SIT), static induction thyristor (SITH), and the recently introduced MOS-controlled thyristor (MCT). The characteristics of these devices are discussed and compared from the viewpoint of power electronics applications. Although the IBGT is well known, the power electronics community is somewhat unfamiliar with the latter three devices. For completeness, a brief review of other power devices, such as the thyristor, triac, gate turn-off thyristor (GTO), bipolar transistor (BJT), and power MOSFET is also incorporated. Future trends are outlined     

PMOS—2000发电市场技术支持系统概述

ＰＭＯＳ－２０００发电市场技术支持系统是适合中国发电市场模式的技术支持系统。它具有实时市场调度功能,包括交易管理、预计划处理、实时调度计划、即时信息发布、能量管理、电能计量、结算／合同管理和电厂报价８个子系统。在设计是充分考虑电力市场和计算机技术的发展,使系统具有开放性和可扩展性。文中详细介绍了其结构配置和基本功能。     

潮流和最优潮流分析中FACTS控制器的建模

综述了最近FACTS控制器的数学模型在电力系统潮流和最优潮流分析中的新进展.不仅讨论了单换流器FACTS控制器,如静止同步并联补偿器(STATCOM)和静止同步串联补偿器(SSSC);而且也讨论了多换流器FACTS控制器,如统一潮流控制器(UPFC)、相间功率控制器(IPFC)、通用统一潮流控制器(GUPFC)和电压源型直流输电(VSC HVDC).此外还讨论了基于电压源换流器技术的HVDC的数学模型.不仅涵盖FACTS控制器的单相数学模型,而且也涉及FACTS控制器的三相数学模型.此外,还探讨了多换流器FACTS控制器的电流、电压以及功率等不等约束在潮流计算中的数学模型及计算机实现.     

Evaluation of the performance of line protection schemes on theNYSEG six phase transmission system

This paper describes the performance of different line protection schemes during testing and operation which were used to protect the first commercially operated six phase transmission line in the world-the New York State Electric and Gas 93 kV (phase to phase and phase to ground) line from Goudey station to Oakdale substation. This project was sponsored by Electric Power Research Institute (EPRI), the Department of Energy (DOE), Empire State Electric Energy Research Corporation (ESEERCO), New York State Energy Office (SEO), New York State Energy Research and Development Authority (NYSERDA) and New York State Electric and Gas Corporation (NYSEG)     

Enhanced leader PSO (ELPSO): A new algorithm for allocating distributed TCSC’s in power systems

Allocation of flexible AC transmission systems (FACTS) devices is a challenging power system problem. This paper proposes a new particle swarm optimisation (PSO) variant, called enhanced leader PSO (ELPSO), for solving this problem. This algorithm is capable of solving FACTS allocation problem in a way leading to lower amounts of power flow violations, voltage deviations and power losses with respect to other optimisation algorithms. Distributed thyristor controlled series compensators (D-TCSC’s) are used. D-TCSC’s are installed at all branches except those with regulating transformers. The reactances of D-TCSC’s are found in optimisation process. ELPSO features a five-staged successive mutation strategy which mitigates premature convergence problem of conventional PSO. ELPSO and other optimisation algorithms are applied to IEEE 14 bus and 118 bus power systems for N-1 contingencies and also for simultaneous outage of four branches. The results show that it leads to lower amounts of power flow violations, voltage deviations and power losses with respect to conventional PSO (CPSO) and eight other optimisation algorithms including genetic algorithm (GA), gravitational search algorithm (GSA), galaxy based search algorithm (GBSA), invasive weed optimisation (IWO), asexual reproduction optimisation (ARO), threshold acceptance (TA), pattern search and nonlinear programming (NLP).     

Nanocomposites-a review of electrical treeing and breakdown

Polymer nanocomposites are composite materials having several wt% of inorganic particles of nanometer dimensions homogeneously dispersed into their polymer matrix. This new type of polymer composite has recently drawn considerable attention because nanocomposites or nanostructured polymers have the potential of improving the electrical, mechanical, and thermal properties as compared to the neat polymers [1]. Polymer nanocomposites are, among other applications, increasingly desirable as coatings, structural, and packaging materials in a wide range of automobile, civil, aerospace, and electrical engineering applications. Also, nanocomposites find applications in medical services, healthcare, and decorative coloring [2], [3]. These new materials show excellent mechanical properties such as high tensile strength, increased hardness and toughness, improved flexural strength modulus, and greater heat and chemical resistance. Polymer nanocomposites are characterized by an enormously large interfacial surface area between the inorganic particles and the polymer matrix into which they are embedded. This ratio is typically more than two orders of magnitude greater than that in traditional microcomposite materials. The percentage by weight of the nanoparticles is usually quite low because of the low nanoparticle percolation threshold, particularly for the commonly used platelet and nanotube particles [4]. However, when the nanoparticle content increases beyond the percolation threshold, the nanocomposite may loose its beneficial properties [5]. Various polymers such as polyamide (PA), polyethylene (PE), polypropylene (PP), ethylene vinyl acetate (EVA), epoxy resin (EP), and silicone rubber (SiR) can be combined with inorganic particles such as layered silicate (LS), silica (SiO2), titania (TiO2), alumina (Al2O3), and magnesia (MgO) [1], and there are a number of papers that describe the tests and the properties of the aforementioned combinations of materials [6]?[10].     

不同结构聚胺酰亚胺的聚合反应机理研究

制备了3种不同结构的聚胺酰亚胺,采用差示扫描量热法(DSC)、热重分析法(TG)和傅立叶转换红外光谱(FT-IR)重点分析了3种结构聚胺酰亚胺体系中的伯胺(-NH2)、仲胺(-NH-)与碳碳双键(-C=C-)的反应及其变化情况,得出了不同结构聚胺酰亚胺的聚合反应机理。     

PLC Channel: Impulsive Noise Modelling and Its Performance Evaluation Under Different Array Coding Schemes

Power-line communications (PLC) is a field that has raised a lot of research in the past years. In this paper, we introduce array codes into the PLC environment and we study the channel's performance. In particular, generalized array codes (GAC), as well as row and column array codes (RAC) are applied. We examine their performance by obtaining three different code rates from each category. Therefore, the (8, 4, 4), (12, 7, 4) and (16, 11, 4) GAC codes as well as the (9, 4, 4), (12, 6, 4), and (15, 8, 4) RAC codes are used, meaning that we obtain code rates of (1/2), (7/12), (11/16), and (4/9), (6/12), (8/15) respectively. In addition, for reasons of completeness, convolutional codes are also being applied under the same channel conditions. Moreover, we suggest a hybrid coding technique, which combines the (8, 4, 4) GAC and the (15, 8, 4) RAC code in order to meet the requirements of the PLC time-varying channel and improve its performance. Concerning the system's design, we take into consideration Zimmermann's model for the PLC channel. We apply Middleton's model for the channel's background and impulsive noise, while we also introduce a novel way of estimating the system's impulsive noise. Finally, the well-known transmission technique of orthogonal frequency-division multiplexing is used. The channel's performance is evaluated in terms of the bit-error rate for different ${rm E}_{rm b}/{rm N}_{0}$ values via computer simulations.      

灵活交流输电技术的发展概况

介绍了灵活交流输电技术产生的背景。阐述了静止无功补偿器及新型静止无功发生器，可控硅控制的中联补偿，可控硅控制的移相器；统一潮流控制器等主要装置的发展状况和目前研究的方向，并提出了这些装置需要研究的问题。     

MPEG-4视频流分析工具

随着MPEG-4标准的制定和应用，提供MPEG-4码流分析手段变得越来越必要。文中在分析基于对象编码的MPEG-4视频流的基础上，给出开发的分析工具。该软件可分析视觉对象序列、视觉对象、视频对象(V0)、视频对象层(VOL)、视频对象面(VOP)、网格对象(MO)、人脸对象(F0)．视频对象面组(GOV)及其它MPEG-4视频编码信息。     

永磁同步电动机在变频空调中的应用

提出了一种采用永磁同步电动机驱动、数字信号处理器、空间磁场定向控制技术和电压空间矢量脉宽调制技术等开发的变频空调控制系统,实现空调的数字化变频调速。与传统变频空调相比,运行性能好,效率更高。     

超长跨距无中继光传输技术

探讨并分析了超长跨距中所涉及的各项关键技术,包括光源谱宽控制技术、前向纠错调制编码技术、高功率增益的EDFA功率放大技术、低噪声指数的分布式喇曼放大技术、通信线路安全及信号监控技术以及传输链路信噪比控制管理技术等。综合这些新技术,有助于大幅度提升无中继光传输距离并有效降低传输系统成本,适于在无中继跨海通信及长距离无中继专用网络等领域中配置应用。此外,还介绍了慧视公司研发的新一代超长跨距无中继光传输系统Anyhaul ULS产品的性能及应用案例。     

西北电网新一代EMS

介绍了西北电网新一代能量管理系统的分布客户／服务器体系结构,分布式应用环境以及系统提供的基本ＳＣＡＤＡ功能和电网应用软件功能,包括自动发电控制,经济调度,网络拓扑处理,状态估计和调度员潮流。     

LSCM: a non-destructive diagnostic tool for examining themicrostructure of polymer dielectric films

Laser scanning confocal microscopy (LSCM) was used to examine the microstructure of polymer dielectric films for voids and imperfections. Sample films examined included polypropylene (PP), polyimide (PI), teflon perfluoroalkoxy (PFA), poly-p-xylene (PPX), and polyvinylidene fluoride (PVDF) under a variety of conditions. LSCM is a powerful tool for the nondestructive evaluation of dielectric films because it can take two-dimensional, confocal image slices of a structure with resolution down to a few microns without any kind of physical damage to the sample. Its basic concept, capabilities, and usefulness in nondestructive dielectric characterization are demonstrated