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991.
从N-S方程出发,考虑稀薄气体效应,推导出长微圆管道中压力驱动的可压缩气体流动的简化控制方程组;采用迭代方法求解此方程组,得到了流动的速度分布、密度分布、质量流量;并分析了影响流量的因素。 相似文献
992.
在我国现行的低电压配电网络中一般采用TT、TN配电方式,即三相四线制配电,为了使分布式发电机组与四线制低压电网相连接,需要选择一个合适的变流器拓扑结构。同时为了提高电网中的电能质量,分布式发电机组需要添加有源电力滤波器(APF)后再接入四线制低压电网中。本篇论文主要进行两种四线制拓扑结构——非分裂链路式四桥臂变流器和分裂链路式三桥臂变流器拓扑结构的性能进行对比分析。主要在控制的难易程度、电磁兼容性(EMC)、中点控制、直流侧母线电压利用率和电路复杂性等方面进行对比分析。本篇论文总结出分裂链路式三桥臂拓扑结构变流器主要性能要优于非分裂链路式四桥臂变流器,主要体现于在相同电路复杂性和直流母线利用率的参照标准下,分裂链路式三桥臂拓扑结构的变流器在电流控制方面更加简单,同时有较小的电磁兼容性问题。 相似文献
993.
Chong Xu Jun Liao Wen Xie Yang Cheng Guoping Zhu Yonghui Yang Chenglu Chen Limei Tao Liwen Niu Yuzhen Wang 《科学通报(英文版)》2000,45(1):64-70
After the establishment of the transformation conditions ofStreptomyces diastaticus No.7 Strain M1033, the integration plasmid pXW for homologous recombination, which contains a 600 bp fragment of incompleteGI (G138P. G247D) gene, has been constructed in order to realize the stable overexpression of theGI (G138P. G247D) which is valuable for large-scale industrial production. The Gigene’s disruption has been realized by pXW’s
integration into M1033 chromosomes via homologous recombination andGI deficient strain ofStreptomyces M1033 has been obtained. The reliability of introduction of mutation has been proved by analysis of recombinant fragment
and affirmance of existence of the mutation, as well as detection of the stability of the deficient strain. 相似文献
994.
Mechanism for chronic pain generation 总被引:4,自引:0,他引:4
Yikuan Xie 《科学通报(英文版)》2000,45(9):775-783
Neuropathic pain and the other abnormalities of sensation induced by axon injury or by peripheral nerve inflammation should
result from functional compensations of the injured neurons during their regeneration. Ectopic distribution of proteins related
to Na+, K+ and Ca2+ channels as well as of receptors on both membranes of injured axon and its cell body becomes a main pacemaker from which
spontaneous ectopic afferent of primary sensatory neurons and crosstalk between neurons occur. Abnormal ectopic afferent activities
lead to disorders of the sensation, such as hyperalgesia, allodynia, spontaneous pain and paraesthesia. Administration of
some ion channel agents and/or α2-adrenergic blockers has shown efficiency in preventing neuropathic pain development and
in relieving neuropathic pain. 相似文献
995.
Six kinds of chemokines including SDF-1α, IP-10, KC, RANTES, MCP-1 and Lymphotactin have been amplified using the primers
designed by ourselves with RT-PCR from the total RNA of a medullary-type murine thymic epithelial cell line MTEC1 cells. The
amplified cDNA fragments of the chemokines have been identified by nucleotide sequencing and Northern blot analysis. The results
demonstrate that there are two different splicing forms of SDF-1 mRNA existing in MTEC1. The concentrated culture supernatant
of MTEC1 shows an intermediate level of chemotaxis to CD4−CD8− thymocytes, which conforms to the biological function of SDF-1. 相似文献
996.
Suping Zhang Side Yao Wenfeng Wang Jie Xie Jianping Zhang Jingquan Zhao Lijin Jiang 《科学通报(英文版)》2000,45(10):899-902
Scavenging of hydroxyl radical (· OH) by phycobiliproteins (C-phycocyanin, Allophycocyanin and R-phycoerythrin) was studied
by competitive kinetics methods. Hydroxyl radicals were generated from pulse radiolysis of aqueous systems saturated with
nitrous oxide (N2O). The experimental results indicated that the three types of phycobiliproteins are all strong scavengers of · OH, the rate
constants are around (2.8-5.6)×109 L · mol-1 · s-1. 相似文献
997.
Sheng Zhang Jianqi Wang Yangbing Ding Shaoli Wu Liqing Xie Chenlin Wen 《科学通报(英文版)》2000,45(4):322-325
Radiation techniques (electron-beam, γ-ray, etc.) are usually used for improving the compatibility between polymer and ingredients
in composite materials. Electron-beam pre-irradiation has been used for the first time to enhance the flame retardance of
EVA copolymer. Efforts are being made to decline the flammability for EPDM copolymer by EB technique and remarkable reduction
has been attained through a series of treatments: pre-irradiation, grafting and saponification. 相似文献
998.
结合工程实例设计出一种基于单片机的电力系统通信规约转换器, 它能够实现主站、RTU以及IEDs设备之间不同通信规约的转换,其工程化应用可为中小型变电所综合自动化系统的改造减少一大笔资金投入. 相似文献
999.
高浓度甲基橙低压湿式催化氧化及动力学研究 总被引:8,自引:0,他引:8
采用低压湿式催化氧化法(LPWCO)处理高浓度模拟偶氮染料甲基橙溶液,考察了温度、H2O2浓度、Fe^2+浓度等因素对去除效果的影响,结果表明,LPWCO法能有效云除废水颜色,同时用一级反应模型拟合了甲基橙溶液脱色的LPWCO反应,由实验数据确定了反应速率方程。 相似文献
1000.