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91.
92.
用保角变换法对共面波导金属厚度效应进行了理论分析,编制了相应的计算机程序,给出了数值解,并对此进行了多元曲线拟合,导出了考虑金属厚度后的形状比k、有效介电常数、特征阻抗、损耗的闭定表达式。用此修正表达式求得特征阻抗及损耗的数值解,并与K.C.格普塔的修正值及实验测量值进行了详细比较,结果表明此修正公式与实验值相符较好。 相似文献
93.
94.
D Sternberg A Peled E Shezen O Abramsky W Jiang F Bertolero D Zipori 《Canadian Metallurgical Quarterly》1996,2(1):29-38
The immunological agglutination reactions of physically absorbed F(ab')2 molecules onto anionic and cationic latex particles have been investigated by means of optical absorbance measurements. These measurements have been conducted under different conditions to determine the most influential factors. Surface F(ab')2 and BSA densities, particle concentration in the reaction medium and polyethylene glycol concentration are some of these factors. Sensitized cationic and anionic latexes differ considerably with respect to their colloidal stability and reactivity. As a general rule, the sensitized cationic latex has a relatively higher colloidal stability and hence, it provides reagents with a better optical response. Less than 0.025 microgram/ml of C-reactive protein has been detected using this particle enhanced optical immunoassay. 相似文献
95.
PJ Oefner SP Hunicke-Smith L Chiang F Dietrich J Mulligan RW Davis 《Canadian Metallurgical Quarterly》1996,24(20):3879-3886
Based on a high-performance liquid chromatographic pump, we have built a device that allows recirculation of DNA through a 63-microm orifice with ensuing fractionation to a minimum fragment size of approximately 300 base pairs. Residence time of the DNA fragments in the converging flow created by a sudden contraction was found to be sufficiently long to allow extension of the DNA molecules into a highly extended conformation and, hence, breakage to occur at midpoint. In most instances, 30 passages sufficed to obtain a narrow size distribution, with >90% of the fragments lying within a 2-fold size distribution. The shear rate required to achieve breakage was found to be inversely proportional to the 1.0 power of the molecular weight. Compared with a restriction digest, up to 40% of all fragments could be cloned directly, with only marginal improvements in cloning efficiency having been observed upon prior end repair with Klenow, T4 polymerase or T4 polynucleotide kinase. Sequencing revealed a fairly random distribution of the fragments. 相似文献
96.
97.
J. Jiang M. D. Olson 《International journal for numerical methods in engineering》1993,36(13):2219-2243
Numerical investigations are carried out to verify the new super element model developed in Reference 1 for non-linear analysis of stiffened box structures. The results presented here are obtained from a variety of examples which are chosen to illustrate the accuracy and convergence of the model in various applications. Good agreement is obtained for most of the problems considered and the present formulation is found to be accurate and economical for preliminary engineering design. 相似文献
98.
SiC(w)/TZP+mullite陶瓷复合材料界面和组成设计与力学性能 总被引:2,自引:1,他引:1
本文从理论上分析了SiC(w)TZP+mullite(p)复合材料界面残余热应力及其在基质内的分布规律。提出在SiC(w)表面涂复Al2O3和在PZT中加入mullite(p)联合作用来降低晶须/基质界面残余热应力的界面设计方案,导出SiC(w)和mullite(p)协同补强PZT的匹配条件。制备了SiC(w)/TZP+mullite(p)复合材料并了SiC(w)表面涂层Al2O3厚度和SiC(w 相似文献
99.
SF Zakharov SH Kwok H Sokoloff HT Chang SP Radko A Chrambach 《Canadian Metallurgical Quarterly》1998,19(10):1625-1630
An automated gel electrophoresis apparatus, recently available commercially, allows one to follow the band during electrophoresis in real time, and lends itself therefore to an evaluation of bandwidth as a function of migration time (the dispersion coefficient), resolution and band shape. These determinations assume the constancy of band area with migration time and at various gel concentrations. The purpose of the present study was to verify these assumptions. Representative proteins and sodium dodecyl sulfate (SDS)-proteins, either natively fluorescent or fluorescein carboxylate labeled, were found to exhibit band areas which approach constancy as a function of migration time in both agarose and polyacrylamide gel electrophoresis, provided that (i) the protein concentration under the band was low enough to obviate self-quenching of fluorescence; (ii) the separation of the protein of interest from contaminants had progressed sufficiently during the time at which band areas were measured; (iii) the baseline under the peak was sufficiently well defined. However, band areas decrease with increasing gel concentration. Protein peaks exhibited leading and trailing tails. The ratio of the combined tail area to total area appeared to be near-constant at varying migration times. However, that ratio increases with increasing gel concentration. The tail area does not appear to be an artifact of fluorometric detection since it is reproduced upon fluorimetric analysis of the protein eluted from gel slices after electrophoresis. However, it may be due to photochemical destruction under the conditions of repetitive fluorometric peak detection. 相似文献
100.
PP-g-AA的制备和表征 总被引:6,自引:0,他引:6
用熔融接枝方法制备了聚丙烯-g-丙烯酸(PP-g-AA)。用光电子能谱,广角X射线衍射,红外光谱和化学滴定方法对接枝物进行了定性和定量表征。讨论了单体和引发剂浓度对接枝率的影响,确定了用红外光谱法测定接枝物含量的经验公式 相似文献