锂离子电池的特点与应用

锂离子电池是一种新型的电池，在视频领域中得到了广泛应用。文章介绍了锂离子电池与镍镉、镍氢电池相比的诸多优点及其在应用中需注意的问题。     

锂离子电池的特点与使用

随着科技的发展,越来越多的新的科技成果运用到广电领域,锂离子电池在视频领域的运用就是一个典型的例子。锂离子电池是1991年发明的,锂离子电池的构造由正极、隔离膜、负极三层组成,电池正极由钴氧化锂制成,负极材料由改性石墨制成,隔离膜采用只允许锂离子通过的聚烯多孔膜。与我们从前使用过的镍镉、镍氢电池相比,锂离子电池具有以下诸多优点。一高能量密度(120wh/kg以上)能量密度即单位重量提供的能量,说得简单点,即同样重的电池所提供的能量。锂离子电池能量密度较以前的电池要高得多,因此,锂离子电池要轻便得多。图1为几种电池的能量密…     

锂离子电池

锂离子电池王鸿麟田金玉王英杰１锂离子电池的工作原理锂离子电池作为一种较理想的蓄电池，近年来已开始在“大哥大”和笔记本电脑中应用．锂离子电池的阳极为石墨晶体，阴极通常为二氧化钴锂（ＬｉＣｏＯ２）．石墨晶体和ＬｉＣｏＯ２都具有层状结构．这种层状结构化合物...     

锂离子和聚合物电池

近几年来,便携式电子设备,尤其是膝上型计算机、蜂窝电话和便携式摄录机的需求已得到引人注目的飞速增长。而这刺激了可充电电池市场的稳定发展,并且使用这些电池的电子设备也已逐渐地变得更小、更轻和更薄。     

项目组讨论平衡车用锂离子电池和电池组标准

2017年3月10日,工信部锂离子电池安全标准特别工作组平衡车电池标准项目组在北京召开了SJ/T xxxx《平衡车用锂离子电池和电池组规范》（计划号：2016-0993T-SJ）和GB/T xxxx《平衡车用锂离子电池和电池组安全要求》（预研）两项标准的草稿讨论会。中国合格评定国家认可中心（CNAS）、中国质量认证中心（CQC）、中国民航科学技术研究院、全国自动化系统与集成标准化技术委员会、纳恩博（北京）科技有限公司、东莞新能源科技有限公司、福建飞毛腿动力科技有限公司、深圳迪比科电子科技有限公司、中山天贸电池有限公司等20余家平衡车与电池企事业单位以及认证检测机构的近30位专家代表参与了讨论。     

锂离子电池：朝阳产业，方兴未艾——国内锂离子电池市场的调查

进入21世纪后，便携电子设备市场呈现爆发式的增长。手机在2002年销量为4．35亿部，2004年的销量达到6．6亿部，预计2005年达到7．2亿部。笔记本电脑在2002年销量为2930万台，2004年达到4150万台，2005年可望超过6000万台。2004年MP3的销售数量为2000万台，而到2005年全球MP3的销售量为3000万台，增长率为50％；2006年的销售数量将增长至4．500万台。便携电子设备市场的规模出现了近百倍的扩展，而所有的便携电子设备都需要电池，手机和笔记本电脑几乎是100％采用锂电池。而MP3为了追求小体积．也是大量使用锂电池。     

聚合物锂离子电池

聚合物锂离子电池是指电解质使用固态聚合物电解质（SFE）的锂离子电池,由于SPE质轻、易成膜、粘弹性好,避免了电解质的泄漏,与液态锂离子电池相比,具有安全性能高、重量轻（比同等规格的液锂电池轻20％～40％）、容量大（比同等规格的液锂电池高5％～15％）、体积小、易塑性高等优点,尤其适用于通讯产品如手机、PDA、笔记本电脑等,被公认为是最具发展潜力和应用市场的电池产品,     

锂电池组的主动电荷平衡

电池系统架构 多年以来,镍镉电池和随后出现的镍氢电池技术一直占据市场主导地位.锂电池只是最近几年才进入市场.然而,凭借其突出的优越性能,其市场份额迅速攀升.锂电池具有惊人的蓄能容量,但单个电池的电压和电流都太低,不足以满足混合动力电机的需要.     

负载平衡实践方法的研究

在机群系统环境下，讨论了负载平衡实践的若干方法，分析了轮转法、最少连接法、加权轮询调度等算法的原理和算法的适用面，有效地解决了机群处理结点的负载平衡问题，并给出CPU资源、内存资源等负载信息采集的Visual C＋＋程序代码。     

面向负载均衡的主动切换

为了解决超密集网络中用户在移动过程中由于小区间干扰和负载不均衡导致的用户服务质量下降的问题,本文研究了一种面向负载均衡的主动切换策略,设计了一种基于双门限的移动切换策略,包含小区内的切换与小区间的切换.通过优化小区内的切换门限,可以最小化系统总资源开销.通过优化小区间的切换门限,能够保证用户实时业务需求的同时均衡网络负...     

Distributed routing for load balancing

Some open-loop and closed-loop control algorithms are discussed for an example of a discrete-event system, namely, the routing of arriving tasks from different arrival streams among several possible service stations. It is shown that it is possible to design open-loop policies that give good performance in a way which is very robust with respect to large changes in the arrival rates. This is possible even though it is assumed that there is no online coordination between the routing algorithms for the different arrival streams. Some further improvements of the performance are possible when a simple feedback policy, namely, overflow routing, is implemented. This also gives reasonable robustness of performance with respect to changes in the service rates     

3GPP LTE系统中小区负载均衡机制的研究

第三代合作伙伴计划(3GPP)长期演进(LTE)系统与上一代无线通信网络相比,在基站传输速率和小区容量上都有了极大的提高,相应地对网络无线资源管理功能也提出了更高的要求.文章探讨了无线资源管理中的一个重要方面:负载均衡的问题.首先分析了网络中小区可能发生过载的原因,并讨论了传统的基于小区切换的解决方法可能存在的风险.随...     

Dynamic load balancing algorithm for distributed system

In distributed systems, it is important to adjust load distribution dynamically based on server performance and load information. Meanwhile, gray release and rapid expansion are the basic requirements to ensure reliability and stability for systems with short version iteration cycles. The traditional Hash algorithm performs poorly in gray release, rapid expansion, and load distribution. To solve these problems, a novel Hash-based dynamic mapping (HDM) load balancing algorithm was proposed. On the one hand, this algorithm can adjust the load distribution dynamically based on server performance and load information. On the other hand, it implements gray release by controlling the ratio of requests assigned to the changed nodes. Additionally, HDM has a higher expansion efficiency. Experiments show that the HDM distributes the load more reasonably, provides a more stable gray release ratio, and has a higher expansion efficiency.     

A double phase-sensitive detector for bridge balancing

The general considerations involved in the design of low-frequency phase-sensitive detectors are reviewed. These include the equivalence of multiplier- and gating-type detectors, of pre- and postdetection filtering with regard to both signal and noise, and of half- and full-wave detection. The various configurations of full-wave chopper circuits using similar or complementary bipolar transistors are compared from the point of view of offsets. A question that has not been previously discussed?the degree of prefiltering needed to avoid noise saturation?is analyzed. These principles are applied to the design of a fixed-frequency detector that is especially adapted to bridge-balancing applications.     

Load balancing routing for single-layered satellite networks

The varying population density leads to imbalanced utilization rate of satellites. To ensure an intelligent engineering of traffic over satellite networks, a distributed routing scheme for single-layered satellite network, load balancing routing protocol based on mobile agent (LBRP-MA) is proposed. For LBRP-MA, mobile agents explore route by migrating autonomously. Upon arriving at destination, mobile agents migrate back. On each intermediate satellite, mobile agents evaluate path cost considering satellite geographical position as well as inter-satellite link (ISL) cost, and finally take ISL congestion index into account to update routing tables. Through simulations on the Courier-like constellation, the proposed approach is shown to achieve guaranteed end-to-end delay bound and decrease packet loss ratio with better throughput, which is especially suitable for data transferring in case of high traffic load. Moreover, results of the complexity analysis demonstrate that LBRP-MA can have low onboard signaling, storage and computation requirements. Furthermore, issues of LBRP-MA such as ISL congestion index and cost modification factor are discussed.     

Achieving Programming Model Abstractions for Reconfigurable Computing

This paper introduces hthreads, a unifying programming model for specifying application threads running within a hybrid computer processing unit (CPU)/field-programmable gate-array (FPGA) system. Presently accepted hybrid CPU/FPGA computational models-and access to these computational models via high level languages-focus on programming language extensions to increase accessibility and portability. However, this paper argues that new high-level programming models built on common software abstractions better address these goals. The hthreads system, in general, is unique within the reconfigurable computing community as it includes operating system and middleware layer abstractions that extend across the CPU/FPGA boundary. This enables all platform components to be abstracted into a unified multiprocessor architecture platform. Application programmers can then express their computations using threads specified from a single POSIX threads (pthreads) multithreaded application program and can then compile the threads to either run on the CPU or synthesize them to run within an FPGA. To enable this seamless framework, we have created the hardware thread interface (HWTI) component to provide an abstract, platform-independent compilation target for hardware-resident computations. The HWTI enables the use of standard thread communication and synchronization operations across the software/hardware boundary. Key operating system primitives have been mapped into hardware to provide threads running in both hardware and software uniform access to a set of sub-microsecond, minimal-jitter services. Migrating the operating system into hardware removes the potential bottleneck of routing all system service requests through a central CPU.     

Achieving inter-session fairness for layered video multicast

The Internet is increasingly used to deliver multimedia services. Since there are heterogeneous receivers and changing network conditions, it has been proposed to use adaptive rate control techniques such as layered video multicast to adjust the video traffic according to the available Internet resources. A problem of layered video multicast is that it is unable to provide fair bandwidth sharing between competing video sessions. We propose two schemes, layered video multicast with congestion sensitivity and adaptive join-timer (LVMCA) and layered video multicast with priority dropping (LVMPD), to achieve inter-session fairness for layered video multicast. Receiver-driven layered multicast (RLM), layer-based congestion sensitivity, LVMCA, and LVMPD are simulated and compared. Results show both proposed schemes, especially LVMPD, are fairer and have shorter convergence time than the other two schemes.