Chinese Experts Contribute to ISO＇s New Toy Standards

正The international standard,ISO 8124-6,Safety of toys–Part 6:Certain phthalate esters in toys and children’s products,was officially issued by ISO worldwide on August 15.It was the first time for Chinese experts to lead the ISO standard development in toys industry.The standard was drafted by a group of Chinese experts from SAC/TC for toys and relevant Chinese departments and finally completed by a dedicated international group of experts.ISO 8124-6 makes a substantive breakthrough in the aspects of the scope of toys,limitation of plasticizer types,control of test cost,accuracy of test,operation convenience,etc.,offering the operational guidance for toy manufactures and testing laboratories.     

A novel COA-based electronically adjustable current-mode instrumentation amplifier topology

In this paper a new topology for implementing Current-Mode Instrumentation Amplifiers (CMIA) is presented. The proposed CMIA is based on two single input-multiple output (SI-MO) current operational amplifiers (COAs) as basic building blocks and 2 resistors. To electronically control the differential-mode gain, a transistor operating in triode region is used which acts as a variable resistor. The significant feature of the proposed CMIA is that the active building blocks operate in closed loop configuration. Therefore it exhibits numerous remarkable features such as improved frequency performance, low THD and very low input impedance. In addition, it has fully differential output which reduces the output noise and increases its application. The proposed CMIA is analyzed and simulated with SPICE program using parameters of 0.18 µm CMOS technology and supply voltage of ±0.9 V.     

Efficient Slew-Rate Enhanced Operational Transconductance Amplifier

Today, along with the prevalent use of portable equipment, wireless, and other battery powered systems, the demand for amplifiers with a high gain-bandwidth product (GBW), slew rate (SR), and at the same time very low static power dissipation is growing. In this work, an operational transconductance amplifier (OTA) with an enhanced SR is proposed. By inserting a sensing resistor in the input port of the current mirror in the OTA, the voltage drop across the resistor is converted into an output current containing a term in proportion to the square of the voltage, and then the SR of the proposed OTA is significantly enhanced and the current dissipation can be reduced. The proposed OTA is designed and simulated with a 0.5 m complementary metal oxide semiconductor (CMOS) process. The simulation results show that the SR is 4.54 V/s, increased by 8.25 times than that of the conventional design, while the current dissipation is only 87.3%.     

上海市某热电厂三联供系统运行效益研究

本文阐述了上海某热电公司运用热电冷联产系统的系统形式、热电公司供给现状,分析该公司全年用能规律、运行策略及联产系统不同季节下热电比,对比两种不同系统形式(热电冷联产系统与分产系统)下的能耗及环境性能并提出优化系统运行的运行策略。结果表明:该热电公司在产生相同的蒸汽量的条件下,热电冷联产系统用煤量少于分产系统,全年整体节煤率约3.94%。热电冷联产系统环境收益比分产系统显著,运行期间减少污染物NOx0.1 t、SO27.1 t。优化运行策略后,夏季、过渡季相对于改进前系统节煤率分别为23%、11%。     

公交企业运营绩效的信息熵与SE-DEA组合评价方法

提出了基于信息熵与超效率DEA模型(SE-DEA)的公交企业运营绩效组合评价方法,弥补了传统DEA模型无法对多个有效率单元再排序的缺陷,并降低了SE-DEA模型受指标维度影响的风险,进一步提高了其判别能力。以12家公交企业为研究对象,将公交行业监管、公交企业运营服务与乘客出行需求相结合,基于组合评价方法对公交企业运营绩效进行评价,并与SE-DEA模型得到的评价结果进行对比分析。结果表明,公交企业运营绩效值波动较大;组合评价方法所得到的公交企业运营绩效排序结果与SE-DEA模型得到的排序结果在总体趋势上是一致的,但两者测算的运营绩效值相差很大,且前者的判别能力比后者更强。根据评价结果提出可行建议,以便于顺利实施"优先发展公共交通"的战略。     

基于力控组态的立体仓库监控系统设计

介绍了以PLC为控制器的立体仓库监控系统设计方案、系统的硬件组成和软件的设计。上位机采用Force control V6.0组态软件为开发平台,实现系统的实时监控,下位机采用三菱FX系列可编程控制器,完成堆垛机、输送机、提升机构及伸缩电机现场设备的手动与自动运行控制,实现立体仓库的存货、取货、盘货等多种作业及报表查询打印功能。具有操作简单、灵活通用、维护方便等特点。     

新型定子永磁式双转子电机运行模式分析与实验研究

提出一种混合动力汽车(hybrid electric vehicle,HEV)用新型定子永磁式双转子电机(stator-permanent-magnet double-rotor motor,SPM-DRM),采用双凸极式电机结构简化了中间转子,有效提高中间转子的机械强度,并克服了双转子永磁同步电机研究中存在的中间转子永磁体散热难的问题。分析SPM-DRM应用于HEV的能量传递原理,结合有限元分析所得电机电磁参数,建立了 SPM-DRM 的数学模型,仿真分析了 SPM-DRM 的多工况运行模式;研制了实验原理样机并搭建基于 SPM-DRM 的动力混合系统实验平台,完成起动运行、纯电动驱动、混合驱动等多种典型工况的实验与分析。实验结果验证了理论分析的正确性、样机设计和控制策略的合理性。为该类电机实际应用于混合动力汽车的进一步研究提供参考。     

基于FPGA的数据采集系统中20MHz模拟通道设计

数据采集系统就是为了完成数据采集过程,由为了完成某些特定信号或一组信号而由一系列软件和硬件组成的软硬件系统.模拟通道作为数据采集系统中的关键部分组成部分之一,其性能指标直接制约了数据采集系统的发展,如何使模拟通道具有更高的带宽,更好的交直流性能,更低的噪声,成为了数据采集系统中模拟通道设计研究的主要内容和关键内容.     

低功耗轨至轨CMOS运算放大器设计

设计了一个1.5 V低功耗轨至轨CMOS运算放大器。电路设计中为了使输入共模电压范围达到轨至轨性能,采用了NMOS管和PMOS管并联的互补差动对输入结构,并采用成比例的电流镜技术实现了输入级跨导的恒定。在中间增益级设计中,采用了适合在低压工作的低压宽摆幅共源共栅结构;在输出级设计时,为了提高效率,采用了简单的推挽共源级放大器作为输出级,使得输出电压摆幅基本上达到了轨至轨。当接100 pF电容负载和1 kΩ电阻负载时,运放的静态功耗只有290μW,直流开环增益约为76 dB,相位裕度约为69°,单位增益带宽约为1 MHz。     

A field operational test on valve-regulated lead-acid absorbent-glass-mat batteries in micro-hybrid electric vehicles. Part II. Results based on multiple regression analysis and tear-down analysis

In the first part of this work [1] a field operational test (FOT) on micro-HEVs (hybrid electric vehicles) and conventional vehicles was introduced. Valve-regulated lead-acid (VRLA) batteries in absorbent glass mat (AGM) technology and flooded batteries were applied. The FOT data were analyzed by kernel density estimation. In this publication multiple regression analysis is applied to the same data. Square regression models without interdependencies are used. Hereby, capacity loss serves as dependent parameter and several battery-related and vehicle-related parameters as independent variables. Battery temperature is found to be the most critical parameter. It is proven that flooded batteries operated in the conventional power system (CPS) degrade faster than VRLA-AGM batteries in the micro-hybrid power system (MHPS).A smaller number of FOT batteries were applied in a vehicle-assigned test design where the test battery is repeatedly mounted in a unique test vehicle. Thus, vehicle category and specific driving profiles can be taken into account in multiple regression. Both parameters have only secondary influence on battery degradation, instead, extended vehicle rest time linked to low mileage performance is more serious.A tear-down analysis was accomplished for selected VRLA-AGM batteries operated in the MHPS. Clear indications are found that pSoC-operation with periodically fully charging the battery (refresh charging) does not result in sulphation of the negative electrode. Instead, the batteries show corrosion of the positive grids and weak adhesion of the positive active mass.