Concentration du virus de l'hepatite a sur des membranes de celluloseHepatitis a virus concentration on cellulose membranes

Viral hepatitis type A is the most prevalent waterborne disease in U.S.A. and the number of cases has been increasing in recent years (Melnick et al., 1978). Till now, few works were performed on Hepatitis A Virus (HAV) concentration in water (Hejkal et al., 1982, Elkana et al., 1983). In this paper the filter adsorption-elution method, widely used with other viruses (Wallis and Melnick, 1967; Fields et Metcalf, 1975; Smith and Gerba, 1982), was selected to concentrate HAV from experimentally-contaminated distilled water. Filtration was performed through two cellulose membranes (RAWP 04700 and HAWP 04700 Millipore). Eluate or filtrate viruses were precipitated by polyethylene glycol 6000. HAV is detected by solid phase radioimmunoassay according to a previously described method (Deloince et al., 1982). Figure 1 shows the results of adsorbing HAV at different pH levels. Analysis of variance pointed out that, for the pH levels between 3 and 4, the differences were not significant (P = 0.05). Table 1 shows the effects of pH and number of passages of 3% beef extract or 0.2 M glycin buffer on HAV elution. For both eluents the differences in function of pH levels and number of passages of eluent through the membrane were not significant (variance analysis P = 0.05). On the other hand, the comparison between the two eluents pointed out the higher efficiency of beef extract (t-test, P = 0.001). After this procedure, HAV replication occurred in human hepatocarcinoma cells PLC/PRF/5 (Fig. 2) inoculated according to a previously described method (Crance et al., 1983). As poliovirus (Sobsey et al., 1973), HAV adsorption is the most efficient at acid pH levels. Between pH 4.5 and 5, the remarkable adsorption decrease might be related to the inversion of the HAV electrostatic charges sign, i.e. to the occurrence of an isoelectric point. The HAV elution is different from the poliovirus one, the efficiency of which increased with pH (Wallis et al., 1972) and eluent passage numbers (Farrah et al., 1976). That might suggest that from pH 7.5, both the HAV particles and membranes have negative charges which give enough repulsive forces to allow a good elution efficiency. Improvement of HAV elution efficiency by beef extract is similar to a result obtained with poliovirus by Landry et al. (1978). This effect might be explained by the proteinous material presence in beef extract. HAV replication in cell cultures shows the biological properties preservation after this procedure.     

NT6000控制系统在电厂制粉系统中的应用

介绍了目前火力发电中较为广泛应用的NT6000集散控制系统。叙述火力发力制粉系统的工艺流程、控制系统主要控制器、相关卡件、卡件排列等硬件系统。该项目在集散控制系统接近和达到国外同类产品的可靠性指标,对解决国内节能减排领域的控制难题、提高当今火力发电制粉系统的自动化水平、节能减排、提高能源利用率的先进控制算法研究有一定的借鉴。     

SM6000型空压机的故障分析与维护

介绍了4300 mm 宽厚板 SM6000型空压机的结构和组成,论述了空压机常见的故障和解决方法.经过改进后,SM6000型空压机运行平稳,故障明显减少,保证了生产的顺利进行     

Tobacco Sorter和Tobacco Scan 6000烟草异物剔除系统的比较

对TobaccoSorter和TobaccoScan 60 0 0系列的烟草异物剔除系统进行了对比 ,从系统组成、烟叶单层化及稳定传送装置、图像获取方式及识别算法、异物的剔除方法、照明光源等方面进行了详细的比较和分析 ,由此看出 :随着相关技术的快速发展 ,应用线性CCD摄像机作为检测装置的异物剔除系统将具有越来越明显的优势。     

6000型包装机主电机制动系统的改进

对6000型包装机主电机电磁制动中存在问题进行了分析,并给出了解决方法:采用2台变频器分别驱动6000型主电机和封签电机;采用英国CD公司的GPD-2402变频器和24Ω/1500kW的制动能耗电阻,使主电机电磁制动改为变频能耗制动。改进后不仅满足了生产工艺要求,而且主电机可用同规格的国产电机代替,大大降低了维修费用。     

油田污水处理系统中人机接口电路的设计与实现

介绍一种基于80C196KC型单片机和可编程键盘显示接口芯片8279接口的设计方法，提供了接口电路的结构图和键盘、显示的程序清单。通过Wave 6000仿真器对所设计的电路和程序进行了验证，实验结果表明接口电路的硬件设计合理，软件可靠，能满足油田污水处理控制系统对人机接口的要求。     

TI TMS320C6000 DSPs的FLASH引导设计与实现

TMS320C6000 DSPs是德州仪器公司近年来着重推广的高性能数字信号处理器芯片系列，不但运算速度快，还内置了一些常用算法的硬件加速器。在通信争信号处理领域，该芯片系列得到了广泛的应用。根据实际使用经验归纳总结了在TMS320C6000 DSPs环境下，FLASH芯片的缟程(包括编程器编程各种在线编程方法)争上电后DSPs的FLASH自举引导过程的多种方法，描述了二次引导程序的编写争配置，并分析了各种方法的优缺点。该文一方面填补了德州仪器公司在这方面文档的欠缺，对通信争信号处理工作者利用该系列芯片搭建独立完整的DSPs评估环境，乃至基于此系列DSP的产品化过程也有较大的推动作用争借鉴意义。     

如何对MAX6000进行实时监控

本讲述了如何利用Syslog日志机制对MAX交换机的运行状况进行实时监控的过程，并提供了相应的监控程序开发思路。     

浅谈TMS320C6000中断程序的实现方法

主要讨论中断服务程序在TMS320C6000 DSP中的几种用C语言来实现的方法。     

液相化学还原法制备不同形貌的多晶纳米镍

采用液相化学还原法,在1,2-丙二醇体系中,分别使用吐温-80（Tween-80）、聚乙二醇-6000（PEG-6000）和十二烷基硫酸钠（SDS）与聚乙二醇-6000（PEG-6000）的混合物作为修饰剂,利用1,2-丙二醇还原相同母体醋酸镍,制备形貌分别为海绵体、纤维状、雪花状的多晶纳米镍;在水体系中,使用SDS为修饰剂,利用水合肼还原相同母体醋酸镍,制备球形多晶纳米镍。通过X射线衍射（XRD）、透射电子显微镜（TEM）、选区电子衍射（SAED）对纳米镍进行表征。利用傅立叶红外（FTIR）分析初步解释不同形貌纳米镍的形成机理。