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71.
A Saccharomyces cerevisiae sequence cloned by serendipity was found to encode a protein that is a new member of the Ypt/Rab monomeric G-protein family. This sequence shows high homology to the yeast genes SEC4 and YPT1 and, like SEC4 and YPT1, is essential for viability. The sequence was localized to chromosome V based upon hybridization to pulse-field gel-separated yeast chromosomes. The sequence has been deposited in the GenBank data library under Accession Number L17070.  相似文献   
72.
叶绿素衍生物4号(CPD4)是一种新型中药光敏剂,本文研究了不同浓度的CPD4分别在含10%不同血型人血清的生理盐水中以及纯生理盐水中的激发和发射荧光光谱,并对结果进行了分析,结论对CPD4在光动力诊断恶性肿瘤的临床应用具有一定的指导意义.  相似文献   
73.
An analytical expression for both band-to-band and band-trap-band indirect tunnelings is used to study the gate-induced drain leakage (GIDL) current of MOSFETs measured before and after hot-carrier stress. The voltage and temperature dependence of GIDL are characterized. Both results show that interface traps situated near the midgap participate in the conduction of GIDL, and band-trap-band indirect tunneling could be the major mechanism. This is further supported by the fact that the percentage increase in GIDL induced by hot-carrier stress is about the same as the corresponding increase in interface-trap density. On the other hand, under low-field conditions, trap-assisted Poole–Frenkle emission dominates over tunneling for temperatures even well below room temperature.  相似文献   
74.
Tests of univariate and bivariate stochastic ageing   总被引:1,自引:0,他引:1  
Concepts of ageing describe how a population of units or systems improves or deteriorates with age. Many classes of life distributions are categorized and defined in the literature according to their ageing properties. An important aspect of such classifications is that the exponential distribution is nearly always a member of each class. The notion of stochastic ageing is important in any reliability analysis, and many test statistics have been developed for testing exponentiality against various ageing alternatives. This paper is an overview of these developments. The author begins with a table of ageing classes together with key references, followed by a brief discussion on the characterization of exponentiality. Test procedures are summarized, and followed by the main review. Tests of exponentiality against other alternatives are explained for randomly censored data. Finally, tests of multivariate ageing properties are listed. Some of the life classes have been derived more recently and, as far as is known, no test statistics have been proposed. On the other hand, several tests are available for some classes. Relative efficiency of a test is discussed whenever appropriate  相似文献   
75.
76.
Negative resistance field-effect transistor (NERFET) devices using either strained InGaAs or unstrained GaAs channel layers have been fabricated. The strained InGaAs channel NERFET's show strong negative differential resistance and large drain current peak-to-valley ratio. The peak-to-valley ratio of the InGaAs channel NERFET is more than 3000 at room temperature and larger than one million (106) at 77 K. The peak-to-valley ratio is controllable by adjusting the collector voltage  相似文献   
77.
不锈钢网架(壳)技术及其应用   总被引:1,自引:0,他引:1  
本文总结了多年来不锈钢网架的研究成果 ,并介绍了部分不锈钢网架的工程应用  相似文献   
78.
卫来贵 《山西建筑》2004,30(3):83-84
结合新版建筑工程施工质量验收规范的学习和施工实践 ,介绍了新版标准与旧标准的差异和特点 ,并就如何贯彻实施新标准、准确掌握检验批等问题作了分析 ,提出了执行中的相关注意事项。  相似文献   
79.
赖祯俊 《四川水利》2006,27(2):53-54
树立和落实科学发展观,除不断深化对科学发展观的科学性、必然性和战略性、指导性的认识,不断增强坚持和落实科学发展观的自觉性和坚定性外,更重要的是要将科学发展观付诸实践,见诸行动,贯穿到促进经济社会发展和推动改革开放的各项工作中去,在实践中将科学发展观转化为强大的物质力量。水利行业贯彻和落实科学发展观,关键在于认清形势,立足实际,把握重点,明确方向,在扎实推进“十个转变”上下功夫。  相似文献   
80.
Dynamic characteristics of piezoelectric bending actuators under low and high electric fields are studied using the asymptotic theory of nonstationary vibrations. The proposed nonlinear model predicts the changes in fundamental resonant frequencies of the piezoelectric cantilever. The predicted resonance amplitude of the tip deflections of the piezoelectric actuators, which increases with the increase in the magnitude of the electric field, well agrees with the experimental results. Additionally, the decrease in the mechanical quality factor with the increase in the electric field, the tip deflection of piezoelectric actuators near resonance frequency,and the amplitude of the tip deflection at the fundamental vibration tone under an applied electric field varying with time have also been obtained using the present model.  相似文献   
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