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821.
通过外加Zeeman磁场在d波超导中,在平均场近似下,自洽求解d波超导能隙和Zeeman能量的方程,研究了Zeeman效应对d波超导序参数和热力学势的影响,阐述了磁性与超导共存条件. 相似文献
822.
A. V. Champakamalini R. Appaswami Rao 《Cellular and molecular life sciences : CMLS》1977,33(4):499-500
Summary The effect of administering barbital sodium, phenobarbitone or butobartitone during pregnancy was investigated in rats. The study shows that these bartiturates affect the litter-size and retard the foetal growth markedly. The embryos produced are significantly undersized.Acknowledgments. The authors wish to express their gratitude to Prof. M. R. Rajasekar Setty for the encouragement received and CSIR, India, for the award of a Research Fellowship to A. V. Champakamalini. 相似文献
823.
Summary Both aspartate and alanine aminotransferase levels increased in digestive gland, foot and mantle on aestivation. The free amino acids and pyruvic acid also increased in all tissues. The significance of these changes is discussed in relation to gluconeogenesis.Acknowledgment. The authors thank Professor K.S. Swami, Head, Department of Zoology, for encouragement and Mr I. Kabeer Ahamed for his help. 相似文献
824.
Free energy perturbation calculations on binding and catalysis after mutating Asn 155 in subtilisin 总被引:1,自引:0,他引:1
Site-directed mutagenesis is a very powerful approach to altering the biological functions of proteins, the structural stability of proteins and the interactions of proteins with other molecules. Several experimental studies in recent years have been directed at estimating the changes in catalytic properties, (rates of binding and catalysis) in site-directed mutants of enzymes compared to the native enzymes. Simulation approaches to the study of complex molecules have also become more powerful, in no small measure owing to the increase in computer power. These simulations have often allowed results of experiments to be rationalized and understood mechanistically. A new approach called the free-energy pertubation method, which uses statistical mechanics and molecular dynamics can often be used for quantitative calculation of free energy differences. We have applied such a technique to calculate the differential free energy of binding and free energy of activation for catalysis of a tripeptide substrate by native subtilisin and a subtilisin mutant (Asn 155----Ala 155). Our studies lead to a calculated difference in free energy of binding which is relatively small, but a calculated change in free energy of catalysis which is substantial. These energies are very close to those determined experimentally (J. A. Wells and D. A. Estell, personal communication), which were not known to us until the simulations were completed. This demonstrates the predictive power and utility of theoretical simulation methods in studies of the effects of site-specific mutagenesis on both enzyme binding and catalysis. 相似文献
825.
V. H. Rao I. V. Mongha M. R. Ansari N. K. Bhattacharyya 《Cellular and molecular life sciences : CMLS》1984,40(8):821-822
Summary Frozen storage of rabbit embryos at the 16-cell stage in 2.0 M dimethylsulfoxide (DMSO) in phosphate-buffered saline (PBS) was achieved by a 2-step procedure. After storage for 10 days at–196°C they were revived by rapidly thawing at 500°C/min. On transfer of these embryos to pseudopregnant foster mothers, 50% survived to term. The difference in in vivo survival between frozen-thawed and frozen-thawed-cultured embryos was not significant.Acknowledgment. The authors thank the Director for the facilities. VHR is supported by Council of Scientific and Industrial Research (India). 相似文献
826.
Y-TZP和氮气压力对GPSSi_3N_4性能的影响 总被引:1,自引:0,他引:1
本文研究了Y-TZP(3mol%Y2O3)和氮气压力对GPSSi3N4陶瓷材料的烧结性能和力学性能、相组成及微观结构的影响,添加5wt%、10wt%、15wt%、20wt%Y-TZP的氨化硅复合材料在1770~1800℃,氮气压力分别为1MPa、2MPa、3MPa下烧成,获得相对密度>95%的烧结体。实验结果表明:添加<10wt%的Y-TZP及增大氮气压力有利于改善氰化硅陶瓷材料的烧结性能;Y-TZP可提高Si3N4基体的断裂韧性,添加15wt%TZP的Si3N4材料断裂韧性可达8.33MPam1/2,与基体相比提高30%,微裂纹增韧和第二相粒子增韧为主要增韧机理. 相似文献
827.
828.
829.
SUN Yuhao WANG Zhe & FU Xiaolan . State Key Laboratory of Brain Cognitive Science Institute of Psychology Chinese Academy of Sciences Beijing China . Graduate University of the Chinese Academy of Sciences Beijing China . Department of Psychology Zhejiang Sci-Tech University Hangzhou China 《科学通报(英文版)》2006,(23)
Gelman and Bloom found that adults and children's object naming was sensitive to how an object was created (man-made or not), but they did not reveal on which specific level of conceptual system this effect was. Using a free-naming task and a force-choice task, two experiments were conducted to test a hypothesis that this effect was specifically on domain level ("artifact/non-artifact" distinction). In Experiment 1, participants were asked to name shortly-depicted objects, rate their confidence, and report their reasons for each naming response. Results showed that most of the naming responses in "man-made" condition were in artifact domain, and most in "natural" condition were in non-artifact domain, although in both conditions names were very divergent on basic level. In Experiment 2, another group of participants were asked to choose one from two names (one in artifact domain and the other in non-artifact domain) to match the same shortly-depicted objects presented in the first experiment. Re-sults of Experiment 1 on domain level were replicated in Experiment 2. These convergent findings supported the hypothesis that the effect of object's origin is specifically on domain level of conceptual system of objects. Reasons explicitly reported for naming responses in Experiment 1 suggested that participants might automatically infer objects' functions in "man-made" condition but not in "natural" condition. Here the function-based hypothesis of artifacts classification is discussed. 相似文献
830.
基于委托代理理论的企业层级结构分析 总被引:1,自引:0,他引:1
付春晖 《科技情报开发与经济》2006,16(12):175-177
运用委托代理理论对层级结构进行了分析,针对层级组织中存在的问题,指出层级结构的扁平化和网络型组织是层级结构组织的高级代替。 相似文献