全介质自承式光缆在特殊跨越条件下的施工技术

在阐述了全介质自承式（all dielectric self—supporting,ADSS）光缆的特性、连接及展放原则的基础上,以几个实际工程为例,介绍了更换光缆时,在需要跨越带电输电线路、公路、铁路、桥梁等特殊跨越条件下的施工技术,如吊装滑轮法、工器具支撑法、架空线织网法等,分析了这些施工工艺的原理,并指出其安全技术要点和施工中的线路监护要求。     

500kV输电线路架空地线更换OPGW施工方法

500kV带电线路停电换线时间很紧，在跨越较多、地形复杂的情况下，需要采用一些特殊的措施来完成施工任务。文章详细介绍了架空地线换OPGW施工时需要采用的特殊措施、容易造成事故的关键位置的处理方法和换线施工方法。     

利用架空地线展放导线的架线方法

此文通过实例，介绍了送电线路放紧线施工中，跨越特殊障碍物并受设备、地理、时间等条件限制时，是如何采用架空地线展放导线的。     

特高压输电线路工程中特殊跨越的研究与应用

随着特高压电力线路建设的快速发展,跨越铁路、高速公路等特殊跨越不断增加,在施工过程中往往采取搭设钢管跨越架或承力索方式进行安全防护。由于传统的管扣式跨越架存在结构繁琐,稳定性差等特点,会严重影响工程的安全、质量、进度。内蒙古上海庙—山东临沂±800 kV特高压直流输电线路工程鲁1标段中,首次采用八分裂1250导线跨越京沪高铁,难度较大。着重介绍特殊跨越使用的新型跨越架及其施工过程,特别是对跨越架搭设进行了分析、计算,研究,提出了具体的施工方案;并且介绍了施工方案在跨越中的具体应用情况,为今后特殊跨越施工提供了借鉴与参考。     

带电跨越防护设施的组合应用

电力线路工程施工中越来越多地出现跨越已建电力线路及交通设施的复杂跨越情况,减少施工期间被跨越电力线路停电和交通运输设施停运,已成为电力线路施工中迫切需要解决的问题。介绍了在大跨距带电跨越运行电力线路防护设施的基础上,组合使用多种不同的跨越防护设施,并实现大跨距跨越高速公路、立交桥、铁路编组站、磁悬浮铁路等特殊跨越物的施工经验,可供借鉴与参考。     

OPGW和ADSS光缆在特殊条件下的施工工艺

2008年初,贵州电力光通信网遭受了历史罕见的雪凝灾害袭击,受损严重,但在短短的一个月内全面抢修恢复完毕.文章介绍了贵州主干光通信网的受损范围、受损现象、受损原因,阐述了受损电力光缆的修复原则、电力光缆施工质量技术要求,总结了灾后重建工程实践中特殊条件对电力光缆施工的影响及相应处理措施,详细介绍了电力光缆抢修中因工期紧张、部分光缆受损区段地形特殊等具体情况而采取的一些特殊工艺措施,如张力场采用延伸转向法布置、直线塔光缆直线挂法改为直线耐张挂法、两盘连牵等,供读者参考.     

500kV输电线路跨越高速铁路施工实践

嘉兴电厂—汾湖500 kV输电线路工程建设中需跨越已运营的沪杭高速铁路,施工单位浙江省送变电工程公司根据跨越档参数,在分析不同跨越架适用条件的基础上,进行跨越架和封顶网形式设计及强度计算,制定了封网施工程序与安全技术措施。通过创新应用自立式跨越架并结合全封闭绝缘封顶网方案,顺利完成了浙江省首例500 kV输电线路在高速铁路的跨越施工。     

承力索带电同档跨越2回500kV线路施工技术

在蔡白线输电线路施工中, 使用承力索带电跨越2 回500 kV 运行线路施工是一次技术创新, 施工难度主要在于首次同时跨越2 条500 kV 带电线路、跨越档距大以及需要考虑天气等不确定因素。施工中采取了相应的措施防止导线偏出封顶网及导线落在封顶网上后承力索下降。通过研究承力索搭设操作过程, 总结了带电跨越线路施工的技术方案。     

索道渡槽施工法的应用

电力线路的跨越施工已成为重要的危险控制点,传统的作业方法是采用搭设跨越架,对跨越物距地面很高、跨越距离较长的线路,采用传统方法很难实现安全施工。在高空展放导地线架线施工中,采用索道渡槽施工法,不受地形限制,适用于跨越复杂环境条件下进行放紧线施工。     

双柱组合悬索式跨越架施工布置的方式和方法

双柱组合悬索式跨越架在输电线路不停电跨越架线施工中得到广泛应用,在不同的地形和施工条件下可因地制宜的设计应用不同跨越架布置方式。文章对双柱组合悬索式跨越架在跨越施工的几种不同的应用方式进行了探讨,对跨越架在不同应用条件下的施工方法、安全事项等方面提出一些建议。     

Dating volcanic eruptions with tree-ring chemistry

Dendrochemical analyses of absolutely dated, overlapping sequences of tree rings allow identification of temporally conscribed, volcanically influenced periods of environmental change. Dendrochemistry, or the study of tree-ring elemental composition, is a promising new technique for reconstructing climate/environmental history at annual resolution. In particular, dendrochemistry may be useful for identifying periods of climatically and/or environmentally effective volcanic activity. Airborne pollution from major volcanic eruptions in the form of increased environmental acidity from sulfur dioxide can cause changes in availability and concentration of certain elements and can increase the availability of those elements in the soil, resulting in increased uptake by trees from the substrate or direct from the atmosphere. In particular, spikes, dips, or major changes in trace element concentration may be an indication of changes in soil or atmospheric chemistry (e.g., Padilla and Anderson 2002). Although there are other records of past volcanism (especially from ice-cores - e.g. Vinther et al. 2005), tree-ring based work (e.g. Salzer and Hughes 2007) offers several important advantages: first, tree-ring series are available with wide spatial coverage from most of the globe, and second, they are datable with annual and even subannual resolution on a fixed (absolute) calendar timescale (whereas even the best ice-core work has errors of several years or more beyond the last few hundred years).     

锂离子电池热失效机理和致爆时间研究综述

随着锂离子电池的不断推广,锂离子电池的安全性越来越受到关注。由于工作条件以及工作环境等的原因,锂离子电池可能工作在一些极端条件如高温、低温下;或者未按规定使用电池,使其工作在过充、过放、短路、冲击等极端条件下,这些可能导致电池发生意外如着火或者爆炸等。从导致锂离子电池爆炸的原因着手,分类综述研究了锂离子电池致爆机理和爆炸时间。     

Incremental Learning of Statistical Motion Patterns With Growing Hidden Markov Models

Modeling and predicting human and vehicle motion is an active research domain. Due to the difficulty of modeling the various factors that determine motion (e.g., internal state and perception), this is often tackled by applying machine learning techniques to build a statistical model, using as input a collection of trajectories gathered through a sensor (e.g., camera and laser scanner), and then using that model to predict further motion. Unfortunately, most current techniques use offline learning algorithms, meaning that they are not able to learn new motion patterns once the learning stage has finished. In this paper, we present an approach where motion patterns can be learned incrementally and in parallel with prediction. Our work is based on a novel extension to hidden Markov models (HMMs) - called growing hidden Markov models - which gives us the ability to incrementally learn both the parameters and the structure of the model.     

同步发电机最优非线性自适应励磁控制器设计

设计了一款最优非线性自适应励磁控制器(Optimal Nonlinear Adaptive Excitation Controller, ONAEC)用于多机电力系统以提升系统故障恢复能力。首先,通过一个高增益扰动观测器(High-Gain Perturbation Observer, HGPO)对由发电机的非线性、不确定性、未建模动态等效聚合而来的扰动进行实时快速估计。随后,该扰动由ONAEC进行在线完全补偿并通过改进樽海鞘群算法(Modified Salp Swarm Algorithm, MSSA)获取其最优控制参数。另外ONAEC具备结构简单、易于实现等优点,且仅需测量发电机功角一个状态量便可实现全局一致的控制性能。最后,进行了两种算例研究,即标称模型以及参数不确定下的三相短路。其仿真结果表明,与比例-积分-微分(Proportional-Integral-Derivative, PID)控制和反馈线性化控制(Feedback Linearization Control, FLC)相比,ONAEC能在各种工况下实现最佳的动态性能,有利于系统受到较大扰动后快速恢复稳定运行。     

Research into the Electrokinetic Properties of Electrographic Liquid Developers

A well-known method based on electrophoretic measurements was applied to evaluating the main parameters of liquid electrographic developers, that is, electrokinetic characteristics (e.g., mobilities, charge, and ￠ potential of particles), as well as the size and numerical concentration of particles. The generalization of this method for polydisperse systems is dealt with, taking into account the possible dispersion of the charges of particles. This allows evaluation of an error in determining the mean values of parameters and sets the limits of applicability of the method. A modification of the calculation is suggested, which would allow the mean concentration of particles to be determined. For a number of systems employed in practice it is shown that the electrokinetic properties of liquid electrographic developers depend on the nature of pigments and their chemical modification (e.g., by the aid of surfactants), and on the parameters of a binder and a dispersion medium. A number of relations are derived from the research work done, which allow the optimum choice of the parameters of liquid electrographic developers to be made.     

基于扰动观测器的电力系统鲁棒滑模控制器设计

针对多机电力系统中的励磁系统,设计一种基于扰动观测器的滑模控制(Perturbation Observer based Sliding-mode Control, POSMC)以提高系统稳定性。首先,将系统的非线性、参数不确定性、未建模动态和外部时变扰动聚合为一个扰动,同时由一个滑模状态扰动观测器(Sliding-mode State and Perturbation Observer, SMSPO)对该扰动进行实时快速估计。随后,通过滑模控制器对该扰动估计进行在线完全补偿以实现全局一致的控制能力。POSMC具备结构简单、可靠性高、不依赖系统精确模型以及仅需测量发电机功角一个状态量等优点。最后,基于机械功率阶跃变化、三相短路以及发电机参数不确定性三个算例验证了POSMC的有效性和鲁棒性,其能在各种工况下实现最佳的动态性能,有利于电力系统发生故障后恢复稳定运行。     

Providing a cushion for wireless healthcare application development

Recent advances in the electronics industry and wireless communication have enabled the evolution of innovative application domains. Smaller embedded processors and systems have allowed a new level of mobile communication and interaction in everyday life. In particular, the expansion of broadband wireless services and the advancement of handheld technology have allowed for real-time patient monitoring in locations where not previously possible. Low-cost sensors and wireless systems can now create a constantly vigilant and pervasive monitoring capability at home, work, and in conventional point-of-care environments (e.g., primary care physician offices, outpatient clinics, and rehabilitation centers). A large research community (e.g., the UCLA Wireless Health Institute) and a nascent industry is beginning to connect medical care with technology developers, vendors of wireless and sensing hardware systems, network service providers, and enterprise data management communities. Wearable devices focusing on personal health, rehabilitation, and early disease detection are now being prototyped. All of this has led to the new notion of "wireless healthcare."     

大口径球阀内部流场的数值模拟与研究

在FLUENT环境下完成了大口径球阀内部流场的三维可视化数值模拟与研究,通过变工况获取相关计算结果,对大口径球阀两种典型形式（即全舱口球阀和特性化球阀）内部流场的涡流和压力分布情况、阀门前后压力降、阀门压头损失系数、阀门流量系数、阀门气穴指数等几个较为重要的阀门特性参数进行了比较与分析。最终以图表的形式对这些参数与阀门开度以及与雷诺数之间的变化规律做了说明并给出了相关结论,供工程实际应用作参考。     

Conductance fluctuations in graphene nanoribbons

Over the past few years, the amazing properties of graphene have led to predictions for its use in a variety of areas, not the least of which is in semiconductor devices. But, the transport is an important aspect of any possible application. At low temperature, fluctuations are observed in the conductance through nanoribbons. These fluctuations arise from the presence of a random potential in the semiconductor, which arises from e.g. impurities present in the material structure. In this work, we examine the nature of these fluctuations in nanoribbons using an atomic basis quantum transport simulation.     

浅谈琼脂作为家庭美容仪的人造皮肤材质的研究

本文主要探讨了测试人员在对家用美容仪进行安全标准相关章节的测试时遇到的一些问题(如有些产品需要直接作用于人体皮肤上才能正常工作)。为了保证测试的准确性和可重复性,工程师寻找并最终确定琼脂凝胶作为人造皮肤的合适材质,并由此展开的一系列相关研究。