印制电路板工艺涂层防湿热、防霉菌、防盐雾试验标准的对比与分析

本文对现有标准中印制电路板工艺涂层的防湿热、防霉菌、防盐雾试验方法进行了对比，分析了各标准在标准试样制备、试验依据方法及表征参数等方面的要求，对比分析结果可为印制电路板工艺涂层三防性能验证试验方案设计提供指导。     

电路板组件随机振动试验的仿真实现

简述电路板组件随机振动试验仿真实现的原理和方法。通过有限元软件对电路板组件模型进行随机振动仿真分析,结合电路板组件随机振动试验的频率响应特性结果验证了仿真分析的有效性。     

印制电路板项目竣工验收监测工作探讨

以福建省莆田市为例,研究分析了印制电路板项目竣工环境保护验收监测现场踏勘中存在的问题,提出要加强对项目的现场核查,以及对环保设施建设及运行、建设内容变更、环境风险、危险废物处理等的建议与对策。     

实验室环境下PCB-HASL腐蚀损伤行为与机理

印制电路板作为机载雷达等设备的重要组成器件,在高温、高湿、多盐的服役环境下更容易遭受腐蚀,诱发各种问题,严重影响设备的使用性和功能完好性.基于编制加速腐蚀试验环境谱,以典型PCB-HASL为研究对象,在实验室开展湿热、酸性盐雾循环加速试验,以宏微观腐蚀形貌、绝缘电阻等性能参数,分析模拟海洋环境下PCB-HASL的腐蚀损...     

电子电气缓蚀剂在印制电路板上的应用研究

使用电子电气缓蚀剂可以有效防止电接触部位的腐蚀和磨损,本文以接触电阻变化率为考核指标,考核电子电气缓蚀剂在不同使用温度、热老化时间和插拔次数下对印制电路板电性能的影响.结果表明:温度试验、热老化试验和耐久性插拔试验的接触电阻变化率分别为3.04％、2.1％和0.9％,远低于MIL-PRF-81309F相关规定,因此电子...     

多导联心电监护系统电磁兼容的印制电路板设计

本文对多导联心电监护系统从印制电路板(PCB)的器件布局、布线等方面来进行了电磁兼容性研究和设计,设计完成的多导联心电监护系统能够获得实时的性能良好的心电信号。在日常生活环境下,对所设计的心电信号系统进行了实时监护测试,电路板在裸露状态下可以检测到稳定的心电信号。此测试结果表明该系统具有良好的电磁兼容性和实际应用意义。     

印制电路板制造业结构优化调整思路探讨

以某典型城市为例,调查印制电路板制造业的经济技术发展现状和污染防治水平,分析该行业的对经济发展的带动作用、对电子信息业的配套作用和对环境的污染影响。在此基础上,提出产业调整思路和淘汰退出机制建议,以期为类似的重污染行业产业政策制定提供决策参考。     

废旧电子电器产品资源化利用技术

介绍了废印制电路板处理及资源化技术、废旧冰箱无害化处理及资源回收技术、电视电脑拆解处理设备、废线缆资源回收生产线等四项废旧电子电器产品资源化利用技术的原理、工艺流程、技术特点及应用案例、经济和社会效益。     

基于敏感参数的锂离子电池加速寿命试验评价方法

本文以18650锂离子电池为研究对象,提出了一种基于敏感参数Var(ΔQ_(100-10))的锂离子电池加速寿命试验评价方法,给出了锂离子电池循环寿命退化V-Q曲线敏感参数Matlab数据分析和神经网络拟合算法,设计开发了高稳定高精度高频采样的加速寿命试验系统,实现对锂离子电池10_～20年长寿命指标的快速评价。     

便携式远程医疗的ZIGBEE系统设计与电磁兼容分析

本文对远程医疗的ZIGBEE系统从印制电路板(PCB)的器件布局、布线等方面来进行了电磁兼容性研究和设计,完成的ZIGBEE监护系统能够实时传输性能良好的心电信号和血氧信号。同时该系统可以实现多节点网络的监控,能够通过ZIGBEE mesh网络实现数据的传输。同时该系统还可以通过协调器发送指令使终端设备休眠或唤醒,实现低功耗便携带的目的。该系统传输的数据误码率低,时延短,冲突少,通过本系统的设计,可以较好地通过网络观察人体的部分生理参数实现便携式远程医疗监护的目的。     

云桌面终端电源端传导骚扰和辐射骚扰整改案例

某云桌面终端在进行中国强制性认证(CCC)时,电磁兼容试验项目电源端传导骚扰、辐射骚扰测试均出现超标现象。将重点从PCB板级电路EMC设计方面剖析其测试不合格原因,并给出相应的整改措施,最后对此案例进行总结,给出类似电子产品在PCB设计时的注意事项,以期能给PCB设计工程师提供一些参考意见。     

Phytoremediation of polychlorinated biphenyl (PCB)-contaminated sediment: a greenhouse feasibility study

Contaminated sediments dredged from navigable waterways often are placed in confined disposal facilities to prevent further spread of the pollutants. Reducing contaminants to acceptable levels would allow for disposal of the sediments and further dredging activity. A greenhouse study was conducted to evaluate plant treatments and the addition of an organic amendment to decrease the concentration of PCB congeners found in Arochlor 1260. Sediment treated with the amendment and either low transpiring plants or no plants had the greatest removal of the PCB congeners. High-transpiring plants apparently prevented the highly reducing conditions required for reductive dechlorination of highly chlorinated PCBs. Most likely, the amendment provided labile carbon that initiated the reducing conditions needed for dechlorination. The sediment moisture content and moisture-related plant parameters were significant predictors of the PCB loss. Carex aquatalis and Spartina pectinata are predicted to be the most effective plant treatments for phytoremediation of PCBs.     

Spatial and temporal distribution of polychlorinated biphenyl (PCB) concentrations in soils of an industrialized city in Turkey

Surface soil (0-5 cm) samples from 43 sampling sites covering the entire urban territory of Bursa, an industrialized city in Turkey, were collected in each season and analyzed for 83 polychlorinated biphenyls (PCBs). The mean concentration of total PCBs (Σ83 PCBs) among all sites over the four seasons was 2121.51 pg/g dry weight (dw), with a range of 207.61-5461.95 pg/g dw. Total PCB concentrations in the soil samples collected near an industrial region were the highest in all seasons. In general, PCB patterns were dominated by low-chlorinated homologue groups (≤ 5 Cl groups at a 79% level). The predominant homologue group found in Bursa city soils was the penta-CBs (29.1%) followed by the tetra-CBs (25.5%) and tri-CBs (17.6%). A total of seven dioxin-like PCB congeners (CB-77, 81, 105, 114, 118, 123, and 126) were found in every sampling location and their mean total concentration for all locations and seasons was 259.27 pg/g dw, with a range of 7.02-1581.13 pg/g dw. A significant relationship (r = 0.77, p < 0.01) was found between the concentrations of dioxin-like PCBs and the seasonal average sum of PCB concentrations. A correlation between light congeners (相似文献   

“混凝沉淀+纳米零价铁”处理印刷电路板生产废水中试研究

提出一种新纳米零价铁反应器(Nanoscale Zero-Valent Iron Reactor,简称NIR)及"混凝沉淀+纳米零价铁"处理工艺,通过实际生产废水进行中试,考察和研究该工艺和NIR技术处理江苏省某市印刷电路板(Printed Circuit Board,简称PCB)工业园区废水的效果。结果表明,此工艺对PCB生产废水中Cu、TP及COD Cr去除率分别可达到97.3%、73.7%、26%,其中Cu处理效果最佳;XRD结果表明,纳米零价铁(Nanoscale Zero-Valent Iron,nZVI)与PCB生产废水反应后含有γ-Fe2O3、Fe3O4、γ-FeOOH、CuO、Cu2O、Cu0等产物。"混凝沉淀+纳米零价铁"工艺处理废水时具有处理效果好、工艺耐冲击性能好、产泥量小、不易造成二次污染等优点。     

空调器印剧电路板(PCB)无铅焊点寿命评估研究

由于无铅焊料的应用,无铅焊点的可靠性问题得到了关注.本文针对无铅焊点的空调器印刷电路板(PCB),结合实际使用条件,采用加速寿命的方式,测试了焊点的寿命.并针对温度循环条件下的焊点,使用有限元模拟技术计算测定了其寿命,并与实验的结果进行了比较,取得了较吻合的结果.     

Distribution of polychlorinated biphenyls and chlorinated pesticide residues in trout in the Sierra Nevada

Organochlorine compounds are known to be atmospherically transported to long distances from their original sources. To understand the influence of California's Sierra Nevada range on the air transport and subsequent distribution pattern of some of these residues within the range, we have chosen salmonid fish as an indicator species. Fish were collected from 10 locations throughout the northern and central Sierra Nevada and polychlorinated biphenyl (PCB), toxaphene, chlordane, and DDT [1,1,1-trichloro, 2,2'-bis (p-chlorophenyl) ethane] residues in muscle tissue were analyzed. Rainbow trout (Oncorhynchus mykiss) were found in all sampling locations, and therefore analyses mainly focused on this species. When similar-sized rainbow trout samples from several similar oligotrophic, high-altitude lakes and streams were compared, it became apparent that altitude is one of the factors affecting the residual levels of PCB (r(2) = 0.882), but not for total DDT, toxaphene, or chlordane in trout. Analysis of correlations among these four organochlorine compound residue groups indicated that there are modest correlations in patterns of distribution between chlordane vs. toxaphene (r(2) = 0.345), and chlordane vs. total DDT (r(2) = 0.239), but toxaphene residues are not correlated with PCB or total DDT. In view of significant correlation to the altitude it is concluded that PCB residue in rainbow trout is a good monitoring tool for studying the effect of high-altitude mountain ranges on the long-range transport and distribution of those persistent pollutants.     

某社保(终端/便民/访客)服务器终端EMC整改案例分析

介绍了某社保(终端/便民/访客)服务器终端在电子产品电磁兼容认证中经常遇见的辐射骚扰和传导骚扰测试项目,重点从PCB板级电路EMC设计方面进行测试不合格原因分析,并给出整改对策。并由此案例引出电子产品电磁兼容设计时的注意事项,以图能给电子产品设计工程师提供参考,使其能以较高概率一次性通过EMC认证。     

印刷线路板在复合环境下的腐蚀

印刷线路板几乎会出现在每一种电子设备当中,它是以绝缘材料辅以导体配线所形成的结构元件。印刷线路板的腐蚀形式符合大气腐蚀的基本规律,但又有自己的特点。本文概述了印刷线路板在气体污染物、灰尘、潮湿、高温等多因素复合环境条件下的失效形式及腐蚀机理,其主要的腐蚀形式是:电偶腐蚀、电解腐蚀和缝隙腐蚀;文中还简单总结了印刷线路板腐蚀的主要影响因素,其主要的影响因素是:湿度、温度、腐蚀性气体和固态污染物等。     

自然通风热老化试验箱换气量不确定度评定

自然通风热老化试验箱(以下简称老化试验箱)主要用于电线电缆的热老化性能测试试验。而需要对箱体性能进行评估的多为老化试验箱的生产厂、电线电缆生产厂的产品检验实验室和开展相关项目的检测机构等公司和部门。温度参数和换气量参数是老化试验箱计量的主要项目,其测量结果的准确程度将直接影响对箱体性能的评估,分析并计算出了换气量测量结果扩展不确定度,对换气量参数的测量结果的可信赖程度具有参考意义。