THE TRANSFER BEHAVIOUR OF SOME CATIONS AT WATER／NITROBENZENE INTERFACE BY SEMIDIFFERENTIAL CYCLIC VOLTAMMETRY

The transfer of Sr~(2+) and Ba~(2+) ion, facilitated by 18-Crown-6 present in the aqueous phase, and of succinylcholine ion at w/nb interface were investigated by semi-differential cyclic voltammetry. A good polarographic curve of succinylcholine ion dissolved in water was obtained in the system of 0.01 mol/l LiCl (w)——0.01 mol/l TBATPB (nb). The peak current is directly proportional to the concentration of SC~(2+) ion. It can be used for the determination of SC and the detection limit is 1.05×10~(-5) mol/l.The apparent D~w and D~(nb) have been estimated. The transfer of Sr~(2+) and of Ba~(2+) at the interface are facilitated by 18-Crown-6 present in the aqueous phase and the peak current is directly proportional to the concentration of 18-Crown-6 in water. This method can be used for the determination of the complexing agent and for the stability constant of the complex formed in the aqueous phase.All the experimental results are in keeping with the theoretical.     

智能温度传感器在测控领域的应用

从智能传感器的发展现状出发,重点介绍了DS18B20、TMP101的性能和典型应用电路,并就其应用特点进行了比较,分析了智能温度传感器在测控领域的应用前景。     

W_(18)Cr_4V钢真空油淬白亮层、熔化层形成原因的试验研究

W_(18)Cr_4V钢真空加热油淬后,表面出现白亮层和熔化层等异常现象。本文利用金相显微镜,显微硬度计、扫描电子显微镜和电子探针等手段对白亮层和熔化层进行了分析研究。试验表明,白亮层、熔化层均是真空油淬增碳的结果。本文对白亮层、溶化层形成原因进行了比较深入的分析探讨提出了产生白亮层必须同时具备的三个条件。     

取代[14]轮烯,[18]轮烯和卟吩的异构体计数

用图论方法对取代〔１４〕轮烯、〔１８〕轮烯和卟吩的构造异构和构型异构体数进行计算。计算结果列表表示。     

Quantitative genetic models of sexual selection

Summary Quantitative genetic models of sexual selection have disporven some of the central tenets of both the handicap mechanism and the sexy son hypothesis. These results suggest that the good genes approach to sexual selection may generally lead to erroneous results.Runaway sexual selection seems possible under a wide variety of circumstances. Quantittive genetic models have revealed runaway processes for sexually selected attributes expressed in both sexes and for attributes of parental care. Furthermore, the runaway could occur simultaneously in a series of populations that straddle an environmental gradient. While the models support the feasibility of runaway processes, empirical studies are needed to evaluate whether runaways actually happen. Estimates of critical genetic parameters are particularly needed, as well as measures of natural and sexual selection acting on the same population.The models also show that sexual selection has tremendous potential to produce population differentiation, particularly in epigamic traits. Differentiation is promoted by indeterminancy of evolutionary outcome, transient differences among populations during the final slow approach to equilibrium, sampling drift among equilibrium populations, and the tendency of sexual selection to amplify geographic variation arising from spatial differences in natural selection. Recent work with two- and three-locus models of sexual selection has produced results that parallel the results of the polygenic models^36–38,58. Thus the feature of indeterminate equilibria (outcome dependent on initial conditions) is common to both types of model.     

七月诗派与九叶诗派之比较

七月诗派与九叶诗派作为四十年代两峰对峙的诗歌流派,共同扎根于动荡的社会现实中,或侧重于乡村和对光明的歌颂,或侧重于城市和对黑暗的诅咒;在艺术上表现为心灵“突入”生活、抒情的张扬、自由诗体与心灵“溶解”生活、玄学的沉思、格律体的对立。     

基于DS18B20的矿用温度传感器

为了满足矿井测温的实际需要，应用数字式温度传感器DS18820和AT89C51单片机，开发了一种矿用实时温度检测系统。该系统采用红外线遥控调校技术，可实现仪器自动校零、报警值界限设定等的遥控操作，提高了整机的密封性和安全性。实践表明，该系统测量数据精确、简单实用、维护方便，满足矿井温度检测的实际要求。     

基于CAN总线的超声波安防系统

智能化安防技术随着科学技术的发展，已迈入了一个全新的领域．安防技术正在朝数字化、网络化、智能化、民用化大步迈进．该文介绍了一种利用80c51单片机、SJA1000CAN总线控制器和超声波探测模块实现对楼宇的网络化安防监控的系统．该系统通过对多个监控点进行实际测试，对非法入侵能进行实时、可靠和正确无误的报警，而且系统成本较为低廉。     

Cr-Fe-Mn粉末混合物的机械合金化及其磁交换作用

对主要成分为Cr72Fe18Mn10的粉末混合物进行机械球磨。采用扫描电子显微镜、X射线衍射仪和Mǒssbauer谱仪对球磨不同时间的样品的结构进行研究。研究结果表明：在球磨过程中，存在铁磁性的a—Fe及Fe基的超精细场分布组元和顺磁性的Cr基固溶体，球磨30h能形成顺磁性的纳米晶Cr-Fe-Mn合金；样品的矫顽力随球磨时间的延长先增加后减小，球磨12h时样品的矫顽力最大，为17．313kA／m；球磨样品在高于Cr的奈尔温度退火后场冷却时的矫顽力大于相应的零场冷却时的矫顽力，主要由体系中的铁磁-反铁磁交换作用所引起，其强弱随球磨时间的不同而不同。     

Ba6-3xNd8+2xTi18O54(x=2/3)的聚合物前驱体法合成研究

以EDTA为络合剂，EG为酯化剂，利用聚合物前驱体法合成了Ba6-3xNd8 2xTi18O54陶瓷，研究了不同的EDTA与金属离子摩尔比对粉末结晶特性的影响，利用DTA，TG和XRD等技术分析了Ba6-3xNd8 2xTi18O54前驱体和得到的氧化物粉末，测试了由x(EDTA)/x(M)=1．00的前驱体得到的Ba6-3xNd8 2xTi18O54(x=2／3)陶瓷的微波介电性能。在900℃预烧x(EDTA)/x(M)=1．00的前驱体3h，单相的Ba6-3xNd8 2xTi^18O54(x=2／3)直接形成，没有出现中间相。1000℃预烧，1340℃烧结的Ba6-3xNd8 2xTi18O54(x=2／3)陶瓷具有最佳的微波介电性能：ε=87．1，Qf=8710GHz。