全钒液流电池充放电测试系统设计

针对全钒液流电池的测试需求,文章对全钒液流电池的工作原理进行介绍,根据全钒液流电池运行参数,设计了一种用于全钒液流电池容量测试所需的自动充放电测试系统。该系统能对全钒液流电池进行恒压、恒流充电以及恒流放电测试,并具有监测单体电池电压功能,在测试过程对电池提供安全保护功能,并对数据进行保存和查看。使用设计的充放电测试系统对全钒液流电堆进行充放电测试,分析了能量效率与充电电流的关系。实验结果显示,该系统能够完成钒电池容量测试,对钒电池测试系统研究以及钒电池测试标准建立有重要参考意义。     

基于STM32的全钒液流电池管理系统的设计与实现

为了解决PLC信息采样端口有限,扩展成本高以及功能多样化受限的问题,设计了基于ARM的全钒液流电池（VFB）管理系统。系统利用霍尔传感器实现电压电流的采集,采用修正卡尔曼滤波法实现剩余电荷量（SOC）估计,利用MCGS组态软件实现数据的实时监测以及故障诊断和显示,并实时控制钒电解液的活化和混合,自主切换工作模式。本电池管理系统可实现电池侧电压、电流和温度等信号的实时数据监测、系统的故障诊断以及保护,并能存储和远程上传数据。现场联机测试结果表明,SOC估计误差可控制在±2%,电池充电时间缩短25%,实时响应速度快。该系统能够提高电池的利用率,防止电池出现过充和过放,运行可靠,已投入批量研制和生产。     

基于无迹卡尔曼滤波单液流锌镍电池SOC估计

针对单液流锌镍电池荷电状态估计(SOC)还未较有为完善的解决方案,提出一种基于无迹卡尔曼滤波(UKF)算法的单液流锌镍电池SOC估计.对单液流锌镍电池工作原理进行介绍,建立单液流锌镍电池二阶等效电路模型,并对电池内部参数进行辨识,通过利用扩展卡尔曼滤波算法(EKF)和无轨迹卡尔曼滤波算法(UKF)分别对单液流锌镍电池的SOC估计,经过仿真分析两种算法的误差,进一步说明无迹卡尔曼滤波算法有较高的精确度,估计误差在2％以内,能够满足单液流锌镍电池荷电状态估计要求.     

航空用大容量锂离子电池研究

基于小容量锂离子电芯并联增容的航空用大容量动力锂离子电池,采用内阻测量法及恒流放电法研究了锂离子电芯并联后的内阻、功率供电特性变化,并开展了过充电、过放电、针刺、加温及短路安全性测试。结果表明:应合理设计并联小容量锂离子的电芯规格及个数,使并联后大容量锂离子电池汇流部分电阻占比基本保持不变。并联未影响锂离子电芯倍率放电容量。与锂离子电芯放电电压平均值相比,大容量锂离子电池在功率输出初期供电电压略低,而在后期反而比平均电压值略高。航空用大容量锂离子电池安全性满足使用要求。     

无人机锂电池免插拔的自动充电系统设计

为了解决无人机锂电池充电不方便、不智能的问题,设计了一种基于嵌入式系统控制的锂电池充电技术方案,可实现对无人机锂电池的免插拔自动充电,并且能够实时监测充电电流、充电电压.在电池充电过程中能够对电池进行均衡保护,防止电池过充,平衡电池每一节电压,延长电池使用寿命,提高电池使用的安全性、可靠性.同时,能够自动检测电池状态,在电池充满后能够自动断电.     

基于RC充电时间过零点不变性的高精度高稳定振荡器

设计了RC充电时间过零点不变性振荡器,该振荡器提供对电压和温度不敏感的高精度高稳定性时钟信号。分析并推导了RC充电过程中过零电压的时间不随电源电压变化的特性,采用温度补偿技术最大限度地保证了RC充电过程中过零电压的时间不随温度变化。基于180 nm工艺实现了该振荡器,仿真结果表明,该振荡器可以稳定输出2 MHz,电压从2.5 V～5.5 V的频率波动小于1%,温度从-40℃～125℃的频率波动小于1%,PVT条件下的最大电流不超过150μA。     

废镉镍电池再生

镉镍电池使用一段时间以后(约反复充电500次至800次),就会出现容量下降,充放电特性差,直至充不上电。造成报废的原因有三个: 一、电解液干枯。充电过程中,由于电池发热,电解液中的水份随着废气从排气孔排出,久而久之造成水份自然蒸发,使电解液干涸。这种情况占多数。二、电解液流失并干枯。有些镉镍电池的制造工艺差,排气孔处封密不好,在反复充电过程中电解液随水份蒸发而排出,至使电解液逐步流失并干枯。这种情况在镉镍电     

自制银锌电池充电器

银锌电池价格较贵,为了物尽其用,我设计了一个充电器,可以对使用过的银锌电池充电,效果很好,现介绍给大家。该充电器在市电稳定的情况下,可以做到恒流、恒压充电。当电池充满电后还可以自动断电保护电池不致过充电。工作原理充电器电路如图1所示。图中,B为电源变压器。220V市电经变压器耦合,其次级产生9V左右的低电压,经D、C整流、滤波,W分压,再经V放大,由射极输出充电电流。调节W,可控制     

锌镍单液流电池二维瞬态等温模型

综合考虑动质量传递、电荷守恒以及电极反应动力学,本文建立了锌镍单液流电池二维瞬态等温模型。在与实验数据对比验证了模型准确性基础上,研究了放电过程中电池内部流场、浓度场的分布及变化规律,并进一步考察了流速和离子浓度对放电性能的影响。研究结果表明：主流区流速较高,由对流控制传质过程,离子浓度分布均匀,多孔介质域和近壁面流速趋于0,由扩散控制传质过程,离子浓度梯度较大。需要更多地关注负极表面锌离子的浓度极化,浓度最大值在出口处的负极表面。 流量每增大一倍放电电压有微小的提升,流量超过5.7 ml/s,这种作用几乎失效。提高锌离子浓度不利于提升电池放电性能,但是提高氢氧根离子浓度对于提升放电电压效果明显。此外,提高电解液流速或者改变离子初始浓度都不会影响总的放电时间。     

全钒液流电堆换热器顺/逆流效率研究

全钒液流电池(VRFB)的电堆内部工作温度不仅影响反应速度,而且影响电解液和膜的电导率、充电时间和循环能源效率,对电池的性能影响很大。VRB系统在实际应用中为了更好地控制温度,通过安装强制冷却装置如换热器进行温度调节,因此换热器的很多参数需进行优化设计。本文主要对控制电堆温度的换热器模块进行顺流和逆流下的效率分析,运用热力学理论,依据钒电池的热力学属性,通过Matlab/Simulink搭建VRB电堆热力学模型;在热力学定律的基础上研究电堆温度与时间函数的热模型,建立ε与传热单元数、冷热流体温度、传热功率参数之间的函数关系,分析在给定传热系数的条件下换热器效率优化,实现对电堆温度更好地控制,为电堆的实际运用提供设计参考。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.