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101.
介绍了近距离深层综采工作面顶板和巷道顶板管理经验,及综采工作面在通过巷道冒项区域时所采取的办法和措施。  相似文献   
102.
Composition Group Vector Space (CGVS) method for estimating melting and boiling point T m , T b of organic compound has been proposed, and the principle of this method has been elucidated. The models for estimating T m , T b have been established and the numerical values of relative parameters have been presented. The average percentage deviations of T m , T b estimation are 7.53 and 1.58, respectively, which show that the present method demonstrates significant improvement in applicability to predict the above properties, compared to conventional group methods.  相似文献   
103.
Hierarchically ordered structures facilitate the incorporation of diverse functions simultaneously. The present report introduces a simple and novel strategy for producing hierarchically ordered polymeric films. Hierarchical ordering of aqueous droplets on a polymer solution is realized by the imposition of physical confinement via various shaped gratings. After drying of the solution, well‐ordered hierarchical structures were fabricated in the remaining polymer film. The size of the grating structure and the lattice size of spontaneous hexagonally packed aqueous pores comprise two different length scales, thereby offering multiscale ordering. Interfacial wetting of the polymer solution to the grating surface was crucial in terms of obtaining a highly ordered structure that can be tuned by dissolving a small amount of surfactant in the polymer solution. The present novel approach provides a new opportunity for lithography‐free fabrication of complex hierarchical structures.  相似文献   
104.
The human follicle-stimulating hormone receptor (FSH-R) consists of two distinct domains of >330 amino acids, the N-terminal extracellular exodomain and membrane-associated endodomain. The exodomain alone binds hormone with high affinity, whereas the endodomain is the site of receptor activation. Coordination of these two domains is essential for successful hormone action but little is known about their functional and structural relationship. In this communication, we report that exoloop 3 of FSH-R constrains follicle-stimulating hormone binding to the exodomain. When the FSH-R exodomain was prepared by truncating its endodomain, the hormone binding affinity of the exodomain was slightly improved, compared with the wild type receptor. The binding affinity was further improved by >3-fold when the exodomain was attached to the membrane-associated domain of CD8. These results suggest that the FSH-R endodomain attenuates hormone binding at the exodomain. As a first step to test this hypothesis, the 11 amino acids except Ala589 of exoloop 3 were individually substituted with Ala. Ala substitution for Leu583 or Ile584 improved the hormone binding affinity by 4-6-fold while totally abolishing cAMP induction, indicating an inverse relationship. The Ala substitution for Lys580 or Pro582 had a similar trend but to a lesser extent. This significant improvement in the binding affinity suggests that the four residues at the N-terminal region of exoloop 3 interact with the exodomain and constrain the hormone binding in the wild type receptor. This effect is specific since substitutions for other than the 4 residues did not improve the hormone binding affinity. Computer modeling shows that the 4 residues can be positioned on one side of exoloop 3. This result and the apparent inverse relationship of hormone binding and cAMP induction suggest that these two essential functions may work against each other. Therefore, hormone binding might be compromised to preserve cAMP inducibility while maintaining a reasonably high, but below maximum, binding affinity.  相似文献   
105.
6-Chloro n-butyl phthalide (CBP) was orally administered to healthy, male Wistar rats pretreated with or without 3-methylcholanthrene (3-MC) by a single dose of 150 mg/kg, and urine samples were collected for 0-24 h. The urine sample was hydrolyzed with beta-glucuronidase, extracted and concentrated for TMS derivatization, and analysed on a GC-MS system for identification of CBP metabolities. Mass spectral analysis suggests that 7 CBP metabolites were present in the urine sample, and similar metabolism patterns were viewed in rats with or without pretreatment with 3-MC. Four main metabolites of CBP in rat urine were identified as alpha-beta oxolate, beta-gamma oxolate, beta-hydroxylate and gamma-hydroxylate, based on their chromatographic and mass spectral properties. Two hydroxylates have been previously identified in CBP metabolism by rat liver microsomes. The other two metabolites with higher polarity were tentatively identified as dihydroxylation products on the n-butyl side chain by the mass spectra of their TMS derivatives. One minor metabolite was found by the isotopic effect of chlorine, but its specific structure was undetermined. The difference between in vivo and in vitro metabolic profiles of CBP is also discussed.  相似文献   
106.
用常规电阻率测井资料确定水淹层的剩余油饱和度   总被引:7,自引:0,他引:7  
韩清忠  率世和 《测井技术》1996,20(5):351-355
油田综合含水越来越高,利用电阻率测井资料确定地层的剩余油饱和度变得非常困难。针对这一问题,提出了确定地层水民阻率和含油饱和度的方法。(1)利用已知的地怪水分析资料,采用井下自然电位刻度,井间对经和双自然电位一方法来示准地层水混合电阻率,然后利用相邻井相同地层的电阻率对比方法求含水饱和度。(2)利用电阻率的横向探测特性,避开阿尔奇公式中m、a选择上的困难,采用横向法计算水淹层目前的含水饱和度。利用以  相似文献   
107.
用偏振灵敏CANS光谱研究尿嘧啶、胸腺嘧啶、胞嘧啶和腺嘌呤四种核苷分子的振动结构。谱的非共振背景被有效地消除,核苷的双键振动模清晰可辨,对每种核苷分子的特征谱线进行了标识,作为在生物分子中识别它们的标志。  相似文献   
108.
应稀土化学发展的需要,我们组建了稀土萃取信息系统。其中包括:数据的来源和数据类型;数据的组织;检索功能;数据间的关联;最优化设计以及萃取剂结构与其物理性质和结构与萃取性能的相关分析研究。  相似文献   
109.
韩寿岭 《辐射防护》1993,13(2):146-147
本文报道了某厂锆(Zr)生产流程中原料(锆英砂,主要成份为 ZrSiO_4)、半成品(ZrC,ZrCl_4)、废渣和成品锆中天然放射性核素~(238)U、~(226)Ra、~(232)Th 和~(40)K 含量测定结果。采用 NaI(Tl)γ能谱法进行测定,结果表明,原料、半成品和废渣中都含有一定的放射性,各生产环节应采取适当的防护措施;成品锆中基本不含放射性,可安全地应用于各个生产和生活领域。  相似文献   
110.
The conceptual study on the accelerator driven system (ADS) that lasted for about five years ended in 1999 in China. As one project of the National Basic Research Program of China (973 Program) in the energy domain, which is sponsored by the China Ministry of Science and Technology (MOST), a five-year-program of fundamental research of ADS physics and related technology was launched in 2000 and passed national review at the end of 2005. The China Institute of Atomic Energy (CIAE), the Institute of High Energy Physics (IHEP), the Institute of Heavy Ion Physics in Peking University (PKU-IHIP) and other institutions jointly carried out the research. The research activities were focused on HPPA physics and technology, reactor physics of external source driven sub-critical assembly, nuclear data base and material study. For HPPA, a high current injector consisting of an ECR ion source, LEBT and an RFQ accelerating structure of 3.5 MeV was built. In reactor physics study, a series of neutron multiplication experimental study has been carried out and still being done. The VENUS facility has been constructed as the basic experimental platform for neutronics study in ADS blanket. It’s a zero power sub-critical neutron multiplying assembly driven by external neutron produced by a pulsed neutron generator. The theoretical, experimental and simulation study on nuclear data, material properties and nuclear fuel circulation related to ADS is carrying on to provide the database for ADS system analysis. The main results on ADS related researches will be reported.  相似文献   
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