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991.
本文介绍一款由通用CMOS集成电路构成的时间继电器。时间设置由数字拨码设定,对其设计要求工作原理图进行了介绍。具体对相应延时时段的实现进行详细的工作分析。 相似文献
992.
L. S. Stoikova 《Cybernetics and Systems Analysis》1999,35(6):965-972
Least upper and greatest lower bounds are obtained for the interval failure rate, when only the first two moments of the time-to-failure
function are known.
Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 141–150, November–December, 1999. 相似文献
993.
Sergio Brando da Motta Enrico Antnio Colosimo 《Reliability Engineering & System Safety》2002,76(2):868
This article presents a statistical approach of analysis and decision that uses reliability techniques to define the best periodicity for preventive maintenance of power system protective relays. Relays are standby devices and may stay in the hidden failure state when they are not working. This state of failure generates difficulties in the determination of preventive maintenance periodicities. A case study presented in this work deals specifically with the reliability of the transmission and distribution system protective relays of CEMIG (the state owned Electrical Power Company of Minas Gerais, Brazil). Preventive maintenance data of protective relays obtained during a 4-year period were used in the proposed method. The choice of the periodicities, distinguished by groups of similar relay and voltage operation levels of the protected systems, is made according to the failure risk level that the company is willing to take. The main result obtained by using this method is a substantial reduction of 62% in the amount of preventive maintenance work load for the relays of the distribution system. 相似文献
994.
995.
996.
Isolation, DNA sequence and regulation of a new cell division cycle gene from the yeast Saccharomyces cerevisiae 总被引:5,自引:0,他引:5
A new complementation group of temperature-sensitive mutants of the yeast Saccharomyces cerevisiae (ts26-1 and ts26-2) has been isolated and characterized. This mutation maps at 40.7 cM from arg8 and 48.9 cM from arg1 on the left arm of chromosome XV of yeast, providing that it is a newly identified gene. The dumbbell-shape terminal morphology of the mutant cells at the restrictive temperatures is a characteristic of mutants defective in DNA replication. To study the defect of macromolecule synthesis in the mutant cells, DNA, RNA, and protein synthesis were measured at both permissive and restrictive temperatures. The data suggest that the primary defect of this mutation is at the initiation step of DNA synthesis. The gene has been cloned from an S. cerevisiae genomic library by rescue of the conditional lethality of the mutants. It is present as a single copy in the haploid genome. DNA-RNA hybridization of the gene has identified 1 kb RNA, which is under cell-division-cycle control. DNA sequence analysis of the gene has identified an open reading frame capable of encoding a protein of molecular weight 25,055 (214 amino acids). 相似文献
997.
东营凹陷南坡异常高压分布与油气运移 总被引:5,自引:1,他引:4
王福勇 《油气地质与采收率》2008,15(3):43-45
东营凹陷南坡异常高压的分布与成藏关系密切,在1500m以下的埋深条件下,可以采用半对数式回归正常趋势线方程求取压实系数,再运用声波时差与地层压力的关系计算剩余压力.研究结果表明,东营凹陷南坡的异常高压在2500m左右开始产生;在平面上,地层剩余压力由洼陷中心向边缘减小,沙三段与沙四段压降特征不同,但主要压降方向均是地下油气运移的主要指向区,其中沙四段存在3个重要油气优势运移指向. 相似文献
998.
波分复用波长路由节点的阻塞特性分析 总被引:4,自引:0,他引:4
利用概率统计理论的方法,从节点层次上定量分析了节点规模、复用波长数目以及波长转换对波分复用(WDM)波长路由网络中波长路由节点的影响。提出了基于概率统计的节点阻塞模型。数值结果突出表明波长转换能力越强的全光节点,其性能越优。为了提高网络资源的使用效率并增强全光网络的灵活性,必须实现全光网络中的虚波长路由波长转换器。通过数值计算找到了阻塞性能和代价的折中,研究中发现配置较低波长转换能力波长转换器的波长路由节点将会具备更强的性价比优势,当前在构建光通信系统时使用弱波长转换能力的光节点更可行。 相似文献
999.
During his long career, Dale B. Harris was at various times a teacher, author, editor, researcher, high school principal, organizational leader, department administrator, and government advisor. He is probably best known for his research on children's drawings, specifically, his extension of the work by Florence Goodenough that resulted in the Goodenough-Harris Draw-A-Person Test. Harris was a participant in the famed Thayer Conference (1954) on school psychology. He was a delegate to the White House Conferences on Children and Youth in 1950 and 1960 and was active in several professional organizations, including the Society for Research in Child Development (SRCD). He served as president of Division 7 (Developmental Psychology) of the American Psychological Association in 1956. He was also active in community organizations, both in Minnesota and Pennsylvania. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
1000.
通过深入研究分析ZXSM-10设备的原理及相关电路,结合故障案例,介绍设备维修的技能,提出检修思路,对相关设备的运行维护具有一定借鉴意义。 相似文献