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91.
室内设计是现代科技和文化艺术的综合产物,它不仅折射出鲜明的社会时代特征,而且还反映了人与自然的关系,创造一个符合人性诉求、让人的心理和生理都感到自然和谐的居住空间已成为现代家居设计发展的趋势.而利用自然的设计元素,注重以人为本,构建自然、建筑和人三者之间和谐统一是以回归自然为理念的室内设计的根本.  相似文献   
92.
Phenyl methylisopropoxyphosphorylformate was studied by high resolution X-ray diffraction. The chemical bonding in the vicinity of the phosphoryl group was studied by analyzing the deformation electron density, the Laplacian of the electron density, and the electron localization function. A P=O...C=O intermolecular contact was revealed and its nature was analyzed.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 553–558, March, 2005.  相似文献   
93.
Bacterial cellulose (BC) is a natural material produced by Acetobacter xylinum, widely used in wound dressings due to the high water‐holding capacity and great mechanical strength. In this paper, a novel antimicrobial dressing made from BC/methylglyoxal (MGO) composite with a dip‐coating method inspired by naturally antimicrobial Manuka honey is proposed, which to our best knowledge, has not yet to be reported. Characterizations by scanning electron microscope and atomic force microscopy show the interconnected nanostructure of BC and MGO and increase surface roughness of the BC/MGO composite. Thermal analysis indicates high temperature stability of both BC and BC/MGO, while compared with BC, BC/MGO exhibits slightly weaker thermal stability possibly due to reduction of hydrogen bonding and increase of crystallinity. Mechanical test confirms the strong mechanical property of BC and BC/MGO nanocomposite. From the disk diffusion antimicrobial test, the BC/MGO nanocomposite with highest MGO concentration (4%) shows great zone inhibition diameter (around 14.3, 12.3, 17.1, and 15.5 mm against Micrococcus luteus, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli). Compared with other antimicrobial wound dressing composite materials, the proposed BC/MGO nanocomposite has among the greatest antimicrobial property against broad‐spectrum bacteria, making it a promising antimicrobial dressing in chronic wounds care.  相似文献   
94.
科学本质作为国际科学教育的重要目标,受到越来越多的关注。但在实践中,教师缺少对科学本质的内涵和具体方面的深度理解,同时缺少有效的科学本质教学的相关指导。本文探讨了基础教育阶段科学本质的8个方面的具体内涵,阐明了科学本质的有效教学的特征,并以“原子结构”为例,为教师开展科学本质教学提供范例。  相似文献   
95.
不正常航班管理的可拓预警模型   总被引:5,自引:1,他引:4  
本文从危机管理的角度。采用可拓学的思想和方法,分析导致航班计划运行发生不正常的危机信号的发散性、可扩性、相关性及蕴含性,建立预警模型对相关信息进行收集、监控和分析,为防范危机发生和减少危机损失提供形式化的可拓处理方法。  相似文献   
96.
对光波及电磁波衍射本性的认识和判断   总被引:3,自引:0,他引:3  
本文明确指出: 边界衍射波具有 π位相跃变性质 ,它是物理存在. 当目前通用的基耳霍夫衍射积 分公式因限制条件不满足而碰到问题时 ,则以前种观点分析为准 .  相似文献   
97.
Reversible phosphorylation of proteins is a post‐translational modification that regulates diverse biological processes. The molecular mechanism underlying phosphoryl transfer catalyzed by enzymes remains a subject of active debate. In particular, the nature of transition state (TS), whether it has an associative or dissociative character, has been one of the most controversial issues. Structural evidence supports associative TS, whereas physical organic studies point to a dissociative character. Here we perform hybrid quantum mechanics/molecular mechanics simulations for the reversible phosphorylation of phosphoserine phosphatase (PSP) to study the nature of the TS. Both phosphorylation and dephosphorylation reactions are investigated based on the two‐dimensional energy surfaces along phosphoryl and proton transfer coordinates. The structures of the active site at TS in both reactions reveal compact geometries, consistent with crystal structures of PSP with phosphate analogues. However, the electron density of the phosphoryl group in both TS structures slightly decreases compared with that in the reactant states. These findings suggest that the TS of PSP has a geometrically associative yet electronically dissociative character and strongly depends on proton transfer being coupled with phosphoryl transfer. Structure and literature database, which searches on phosphotransferases, suggest that such a hybrid TS is consistent with many structures and physical organic studies and likely holds for most enzymes catalyzing phosphoryl transfer. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011  相似文献   
98.
用格子玻尔兹曼方法对微圆管管束外混合对流的换热情况进行了数值模拟研究。在充分验证程序正确性的基础上,对混合流动绕流时不同壳侧进液角度,不同雷诺数Re以及瑞利数Ra等方面对传热的影响进行模拟研究,对衡量传热效果的Nu数及温度场进行了对比,总结出了换热规律。为高效微管换热器的开发提供了理论指导。  相似文献   
99.
乙烷含量对天然气、煤层气燃烧速率和火焰稳定性的影响   总被引:1,自引:0,他引:1  
本文在定容燃烧弹中,研究了高温高压(0.75 MPa,450 K)下甲烷-乙烷-空气预混合气火焰传播规律,并系统分析了当量比、混合气中乙烷含量对混合气层流燃烧及火焰稳定性的影响.实验结果表明:随着混合气中乙烷含量的增加,不同当量比下无拉伸火焰燃烧速率均增大,马克斯坦长度增大,表明火焰稳定性增强.在实验范围内,无拉伸火焰...  相似文献   
100.
Optical absorption, Electron Paramagnetic Resonance (EPR) studies are carried out on lead zinc phosphate glass systems doped with Cr3+ and VO2+. From optical absorption investigations the crystal-field parameters Dq, B and C are evaluated. EPR measurements on Cr3+ systems indicate that Cr3+ ions are located at sites with low symmetry. EPR spectra of vanadyl doped system revealed the characteristic nature of vanadyl ion. Spin-Hamiltonian and hyperfine values are evaluated for both the systems. Optical absorption spectra of vanadyl doped system revealed three bands that are characteristic of VO(II) ion in tetragonally distorted octahedral site. By correlating both EPR and optical data, the dipolar coupling constant (P) and Fermi-constant coupling parameter (κ) and molecular orbital coefficients β?2, eπ?2 are evaluated. Electron Paramagnetic Resonance and optical absorption studies showed that the chemical bonds of Cr3+ ions and VO2+ ions with the ligands have more covalent nature. From these studies it is also observed that lead spinals are playing major key role in sustaining the covalent nature of bonding.  相似文献   
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