Advances in rapid and effective break-in/conditioning/recovery of automotive PEMFC stacks

Automotive proton exchange membrane fuel cell stacks need to meet manufacturer specified rated beginning-of-life (BOL) performance before being assembled into vehicles and shipped off to customers. The process of “breaking-in” of a freshly assembled stack is often referred to as “conditioning.” It has become an intensely researched area especially in automotive companies, where imminent commercialization of fuel cell electric vehicles (FCEVs) demands a short, energy- and cost-efficient, and practical conditioning protocol. Significant advances in reducing the conditioning time from 1 to 2 days to as low as 4h or less, in some cases without the use of additional inert gases such as nitrogen, and with minimal use of hydrogen, and specialized test stations will be discussed.     

微型热驱动热声热机热端换热器的优化设计

该文基于热声环境,采用厘米级扁管和deltaE数值计算对微型热声换热器进行了优化设计。     

Fast-cycle trace analysis of dioxin in flue gas. Monitoring of the incineration of dioxin-containing waste from seveso

The fast trace analysis method used to monitor 2,3,7,8-TCDD in stack gas during the incineration of the waste from Seveso is described. The sampling of volatile organic compounds from flue gases, distributed between all three aggregation states, is based on a micromethod developed for the trace analysis of water using a specially dimensioned adsorptive charcoal filter (1.5 mg charcoal). In conjunction with subsequent GC/MS measurements the rapid “fast cycle trace analysis” ensured specific 2,3,7,8-TCDD detection down to 100 pg per m³ flue gas in cycle times of about 1–2 hours.     

Turbo Pascal的并发程序单元

对用Turbo Pascal3.0实现的并发设施作了修改,修改后的子程序收入两个外部程序单元。它们可供Turbo Pascal 4.0及以上版本成功地调用。     

VB与Fortran的混合编程

在一个大型应用软件的实现过程中 ,有时需要混合使用多种语言工具 ,以满足系统综合任务要求。本文详细介绍了VisualBasic与Fortran两种语言混合编程中的几个基础技术问题 ,并就两种语言之间调用约定的协调 ,包括标示符命名、参数传递方式等 ,以及动态链接库的导出和导入 ,给出了具体的实施方法。     

Tuning Garwick's algorithm for repacking sequential storage

Garwick's algorithm, for repacking LIFO lists stored in a contiguous block of memory, bases the allocation of remaining space upon both sharing and previous stack growth. A system whereby the weight applied to each method can be adjusted according to the current behavior of the stacks is discussed.We also investigate the problem of determining during memory repacking that the memory is used to saturation and the driving program should therefore be aborted. The tuning parameters studied here seem to offer no new grasp on this problem.     

Reducing power losses caused by ionic shortcut currents in reverse electrodialysis stacks by a validated model

Both in electrodialysis and in reverse electrodialysis ionic shortcut currents through feed and drain channels cause a considerable loss in efficiency. Model calculations based on an equivalent electric system of a reverse electrodialysis stack reveal that the effect of these salt bridges could be reduced via a proper stack design. The critical parameters which are to be optimized are ρ/r and R/r, where ρ is the lateral resistance along the spacers, R is the resistance of the feed and drain channels between two adjacent cells, and r is the internal resistance of a cell. Because these two parameters are dimensionless, different stacks can be easily compared. The model is validated with two experimental stacks differing in membrane type and spacer thickness, one with large ionic shortcut currents and one where this effect is less. The loss in efficiency decreased from 25 to 5% for a well-designed stack. The loss of efficiency in reverse electrodialysis and in electrodialysis can be reduced with the aid of the design parameters presented in this paper.     

广西电子政务外网IPv6网络平台设计

【目的】设计一套适合于广西电子政务外网国际互联网协议第4版(Internet Protocol version 4,IPv4)网络向国际互联网协议第6版(Internet Protocol version 6,IPv6)网络过渡的平滑演进方案,以此为据指导建设广西电子政务外网IPv6网络平台。【方法】在广西电子政务外网基于多协议标签交换虚拟专用网络(MultiProtocol Label Switching Virtual Private Network,MPLS VPN)技术设计建设的IPv4网络平台基础上,采用IPv4/IPv6双栈技术建设IPv6平面,IPv6提供商边缘路由器技术(IPv6Provider Edge,6PE)和IPv6VPN提供商边缘路由器技术(IPv6VPN Provider Edge,6VPE),实现在IPv6平面建设完成前的政务外网IPv6用户接入,分阶段实施IPv4网络平滑过渡升级到纯IPv6网络。【结果】完成广西电子政务外网IPv6网络平台总体架构、演进路径设计,最终将政务外网建设成为纯粹的IPv6网络。【结论】平滑演进方案提供了一种持续性的业务迁移方式来实现广西电子政务外网网络平台支持IPv6的能力,并逐步演进为IPv6网络。     

Emissions of polycyclic aromatic hydrocarbons from coking industries in China

This study set out to assess the characteristics of polycyclic aromatic hydrocarbon（PAH） emission from coking industries,with field samplings conducted at four typical coke plants.For each selected plant,stack flue gas samples were collected during processes that included charging coal into the ovens（CC）,pushing coke（PC） and the combustion of coke-oven gas（CG）.Sixteen individual PAHs on the US EPA priority list were analyzed by gas chromatography/mass spectrometry（GC/MS）.Results showed that the total PAH concentrations in the flue gas ranged from 45.776 to 414.874μg/m³,with the highest emission level for CC（359.545μg/m³）.The concentration of PAH emitted from the CC process in CP1（stamp charging） was lower than that from CP3 and CP4（top charging）.Low-molecular-weight PAHs（i.e.,two- to three-ring PAHs） were predominant contributors to the total PAH contents,and Nap,AcPy,Flu,PhA,and AnT were found to be the most abundant ones.Total BaP_eq concentrations for CC（2.248μg/m³） were higher than those for PC（1.838μg/m³） and CG（1.082μg/m³）,and DbA was an important contributor to carcinogenic risk as BaP in emissions from coking processes.Particulate PAH accounted for more than 20%of the total BaP_ec| concentrations,which were significantly higher than the corresponding contributions to the total PAH mass concentration（5%）.Both particulate and gaseous PAH should be taken into consideration when the potential toxicity risk of PAH pollution during coking processes is assessed.The mean total-PAH emission factors were 346.132 and 93.173μg/kg for CC and PC,respectively.     

1kW熔融碳酸盐燃料电池组研制

1kW熔融碳酸盐燃料电池 (MCFC)组由有效电极面积为 2 4 0mm× 140mm的 30个单电池组成 .系统采用内部分配方式供给气体 ,通过设在电池组底部和四个侧面的电炉丝进行加热 .在常压和 65 0℃条件下 ,分别以氢气和空气作燃料和氧化剂 ,放电电流密度为 15 0mA/cm2 时 ,平均每电池的输出电压达到 0 .7V .在运行的 30 0h内 ,电池组峰值输出功率达到 1.0 6kW .