基于RPC的同相供电系统供电运行能量多维控制研究

为确保高速铁路安全、可靠、经济运行,提出高速铁路同相供电系统供电运行能量多维控制方法。分析供电系统组成结构与供电过程,利用潮流控制器补偿该系统功率,确保系统稳定运行;结合三相不平衡程度、电压电流波形畸变等指标构建运行能量的最佳负载模型,使传输能量损失降到最低;经过对2个供电臂电流的有功与无功补偿,消除负序电流;制定铁路功率调节器控制策略,获得降压变压器变化情况,保障直流侧电压稳定;再使用比例积分控制器获取电流理想值,得出控制信号,实现供电运行能量多维控制。仿真实验证明,所提多维控制方法能提高三相电流平衡程度,达到均压稳定效果。

基于耗散结构理论的社会工作能量运行原理研究

增能(Empowerment)理论越来越被广泛应用到社会工作实践领域中,但其概念使用一直争论不断且未形成一套完整的理论实践框架。回顾社会工作增能理论的发展脉络,其核心关注人的能量及其缺失状态,而人的能力、权力等建立在能量运行基础之上,在进行社会工作的助人原理讨论时需关注这一问题。本文利用耗散结构理论中对能量变化的探讨,能够更好地解释社会工作中能量运行原理和实践过程,以明确增能理论的助人原理。运用耗散结构理论,分析人的能量运行变化、能量运行过程等,关注人在发展状态中能量变化、内在系统与外部系统能量互动关系以及提升能量的可能途径。在社会工作助人实践中,形成"能量评估—意义解释—目标设定—情境契合—体验反馈"的能量运行模型和工作流程,改变服务对象过去混乱无序的能量缺失状态,重新获得能量以掌控自我生活。

微电网群体系架构及能量协同优化运行的SoS方法初探

含多类型分布式电源、负荷的微电网群呈现出体系(system of systems,So S)的独立自主、归属、可联、异质等特性。该文从So S方法论角度及其自我适应和自我组织能力的机制出发,分析论证了微电网群是一种典型分散式复杂自适应体系(decentralizedcomplexadaptiveSo S,DCASoS)的观点。基于此,初步探讨了微电网群能量管理的体系架构及协同优化运行问题,从微电网群DCASoS基本特征的架构建模和微电网群能量协同优化运行方法两方面展开,提出基于DCASo S的微电网群能量协同优化运行架构,力求充分挖掘微电群涌现出的正面效应,避免负面影响,提升微电网群的综合效能,相关成果能够为微电网群能量协同优化运行的研究提供新方法和理论依据。

城市轨道交通能量运行控制系统

城市轨道交通和干线铁路高速增长带来的能耗、碳排放等问题愈发引起社会的关注。为提升城市轨道交通系统能量利用效率,文章提出一种用于城市轨道交通牵引供电网的能量运行控制系统。该系统采用4G通信获取每列车的瞬时功率和位置、牵引供电系统的参数以及变电站和双向变流器的实时状态信息,依此迭代计算网络空间矩阵,完成牵引供电网络的数字重构。基于重构的牵引供电网络,能量运行控制系统根据目标函数以及系统物理约束,采用智能算法寻优牵引变电站直流输出电压指令,并下发给全线路双向变流器,实现整条线路的潮流分配,从而使城市轨道交通牵引电力系统具有更好的供电质量和更高的效率。通过对采用该能量运行控制系统的某城市地铁线路进行现场测试,结果显示,系统总体效率提升了0.767%,验证了所提城市轨道交通能量运行控制系统的有效性。

Evaluation of tidal stream energy and its impacts on surrounding dynamics in the Eastern Region of Pingtan Island, China

Using an improved FVCOM numerical model, combined with the momentum-sinking scheme based on the structural characteristics of specific turbines, this study analyzed the temporal and spatial distributions of tidal energy resources before and after the deployment of tidal turbines near Pingtan Island, China. Considering factors such as the distribution of tidal stream energy, bathymetry, topography, and the design parameters of the turbines, an appropriate location for a demonstration tidal turbine was selected and the corresponding energy resource was evaluated. Several sites with strong tidal streams were considered： south of the northern cape, east of the southem cape, and the southern end of Haitan Bay. The former was thought most suitable for the deployment of a tidal energy turbine, with projected power generation for approximately 470 h per month. The average power of this demonstration was about 2.4 kW, and the annual electricity output was approximately 17.47 MWh. The intervention of the turbine device had little influence on the near-field tidal stream or water level. The tidal stream was reduced slightly in the area south of the northern cape, although the effect weakened further from the turbine. Conversely, the velocity increased slightly on both sides of the demonstration site. The difference in current speed with and without the turbine was greater at slack tide than still tide. The influence of turbine operation on water level was minor. The method adopted in this study can be considered a reference for the selection of sites for the demonstration of tidal stream energy. However, the method is unable describe the dynamic characteristics of the turbulent flow surrounding the deployed turbines, which has an important role regarding the optimal designs of the turbine blade and pile foundations. Therefore, we will continue to work to improve this model in future research.

Enrichment of Semi-Volatile Organic Acids from Aqueous Solutions by Multiple-Effect Membrane Distillation

Multiple-effect membrane distillation （MEMD） process for enriching semi-volatile organic acids from their individual aqueous solutions was performed by using a hollow fiber-based air gap membrane distillation （AGMD） module with the function of internal heat recovery. Aqueous solutions of glyoxylic acid, glycolic acid, lactic acid, pyrnvic acid, malonic acid and glutaric acid were used as model feed. For a feed of 1% （mass fraction）, each acid could be enriched for 8--20 times, which depended on the surface tension of the concentrate. The operation performance of MEMD process was characterized by permeation flux J, performance ratio PR and acid rejection rate R. The effects of cold feed-in temperature, heated feed-in temperature, feed-in volumetric flow rate and feed-in concen- tration on MEMD performance were experimentally evaluated. Maximum values of J, PR and R were 4.8 L/（h-m2）, 9.84 and 99.93%, respectively. Moreover, MEMD process demonstrated a fairly good stability in a long-term experiment lasting for 30 d when aqueous solution of 4% （mass fraction） lactic acid was used as a feed.

浅谈微电网的研究与应用

微电网作为分布式电源接入电网的一种有效手段,是智能配电网的重要组成部分,具有巨大的社会和经济意义。首先介绍了国内外微电网研究的最新进展以及目前微电网的主要结构,继而重点从微电网的规划设计、能量管理与运行优化、保护控制等方面进行了详细的评述。在规划设计方面介绍了可再生能源与负荷需求分析、规划设计建模和算法优化方法,在能量管理与运行优化方面介绍了负荷预测方法和优化调度方法,在微电网保护与控制方面重点从三个控制层次介绍了微电网控制,最后结合智能配电网应用对微电网技术的发展前景进行了展望。

Economy of Energy during Refrigerating Machine Operation

Idealized cycles of refrigerating machines with adiabatic and isothermal compression of refrigerant vapor were investigated. Energetic characteristics of cycles： specific mass and volume cooling capacity q0 and qv, work of compression 1, refrigerating coefficient of performance e and power N for drive of compressor were compared. These characteristics were calculated for eight refrigerants at temperature of their condensation 30 ℃ and temperatures of boiling -15℃ and -30 ℃. The calculations show that the use of isothermal compression of refrigerant vapor ensures economy of energy during refrigerating machine operation.

Time-Frequency Analysis of EEG Signals Evoked by Voluntary, Stimulated and Imaginary Motions

In order to investigate the characteristics of sensorimotor cortex during motor execution(ME), voluntary, stimulated and imaginary finger flexions were performed by ten volunteer subjects. Electroencephalogram(EEG) data were recorded according to the modified 10-20 International EEG System. The patterns were compared by the analysis of the motion-evoked EEG signals focusing on the contralateral(C3) and ipsilateral(C4) channels for hemispheric differences. The EEG energy distributions at alpha(8—13 Hz), beta(14—30 Hz) and gamma(30—50 Hz) bands were computed by wavelet transform(WT) and compared by the analysis of variance(ANOVA). The timefrequency(TF) analysis indicated that there existed a contralateral dominance of alpha post-movement event-related synchronization(ERS) pattern during the voluntary task, and that the energy of alpha band increased in the ipsilateral area during the stimulated(median nerve of wrist) task. Besides, the contralateral alpha and beta event-related desynchronization(ERD) patterns were observed in both stimulated and imaginary tasks. Another significant difference was found in the mean power values of gamma band(p<0.01)between the imaginary and other tasks. The results show that significant hemispheric differences such as alpha and beta band EEG energy distributions and TF changing phenomena(ERS/ERD) were found between C3 and C4 areas during all of the three patterns. The largest energy distribution was always at the alpha band for each task.

A Nodal Electricity Market Design Based on Regulated Access to Transmission Network

Accomodation of power system constraints with the market mechanism is encountered as a major challenge along the way toward implementation of different electricity market designs. Allocation of fixe or flow-dependent inter-zone trading capacities by the PX （power exchange） can not be accepted unreservedly. The paper is meant to show that a nodal electricity market design that is based on bids for local energy and a regulated transmission access including allocation of ＂entry-exit＂ transmission capacity would be the desired solution. The market players could easily optimize their portfolio while the TSOs （transmission system operators） are requested to mobilize the network＇s in-built flexibility to increase the cross zonal capacity. In the proposed market design, the PX＇s allocation of trading capacity is clearly separate from the TSO＇s management of the power system operational constraint5. Clear operator roles would enlarge access to electricity market as well as market integration of variable RESs （renewable energy sources） that are critically dependent on short notice access to regionat markets,

Internet-Oriented Optimization Schemes for Joint Compression and Encryption

Compression and encryption are widely used in network traffic in order to improve efficiency and security of some systems.We propose a scheme to concatenate both functions and run them in a paralle pipelined fashion,demonstrating both a hardware and a software implementation.With minor modifications to the hardware accelerators,latency can be reduced to half.Furthermore,we also propose a seminal and more efficient scheme,where we integrate the technology of encryption into the compression algorithm.Our new integrated optimization scheme reaches an increase of 1.6X by using parallel software scheme However,the security level of our new scheme is not desirable compare with previous ones.Fortunately,we prove that this does not affect the application of our schemes.

Study on Negative Impact of Harmonic Components on Sensitive Electric Equipment

Distribution systems operators are often confronted with declined power quality, which can cause substantial economical losses. The problem analyzed in paper concerns thyristor controlled direct current motor used for ski-lift in ski resort as a source of disturbances with negative impact on sensitive electric equipment, which is then unable to operate correctly. To solve mentioned problems, series of measurements of voltage quality parameters were carried out according to the respective valid standards. Crucial power quality parameters necessary for parallel power active filter design were then analyzed. Power active filter compensates power factor and filters characteristic current harmonics. After power active filter was put into operation, power quality problems were eliminated. Payback period is estimated up to four years.

Research on the detecting methods of singularity in deformation signal based on two kinds of wavelet entropy

There are various influencing factors that affect the deformation observation, and deformation signals show differ- ent characteristics under different scales. Wavelet analysis possesses multi-scale property, and the information entropy has great representational capability to the complexity of information. By hamming window to the wavelet coefficients and windowed wavelet energy obtained by multi-resolution analysis （MRA）, it can be achieved to measure the wavelet time entropy （WTE） and wavelet energy entropy （WEE）. The paper established deformation signals, selected the parameters, and compared the sin- gularity detection ability and anti-noise ability of two kinds of wavelet entropy and applied them to the singularity detection at the GPS continuously operating reference stations. It is shown that the WTE performs well in weak singularity information de- tection in finite frequency components signals and the WEE is more suitable for detecting the singularity in the signals with complex, strong background noise.

磁绝缘理论综述

本文是对磁绝缘认识的综述。提出了对常值阻抗区稳态流的单粒子描述，层流理论，准层流及任意动量流理论；讨论了非稳态流及相关的层流近似，最小能量运动点及有关稳定性的一些问题；介绍了等效电路模拟，粒子模拟及任意动量流的二维时变计算方法；介绍了过渡的概念，进行层流分析，得到一些准则。

A review of self-assembled monolayers as potential terahertz frequency tunnel diodes

In this review, we describe the principles of the tunnel junction, self-assembled monolayer （SAM） application techniques, experimental testbed fabrication, and characterization of the films and devices. In addition, techniques for directed application, removal, and functionalization of the monolayers are discussed. Bottom-up fabrication techniques have seen increased attention because of their versatility and ease of use. These films see mechanical uses as surface modifiers and micro-scale lubricants. Advances in nanowatt electronics and ultra-low power sensors have opened up an energy harvesting niche for solutions which would have proven ineffective just some years ago. The focus of this study is the two- terminal junction which has potential applications in THz rectification for energy harvesting, medical imaging, and defense sensing. The quantum theory of operation behind these devices is touched on briefly---describing tunneling through the organic monolayers. Commentary on trends in research and potential future work are presented as well.