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991.
通过理论分析和实际工程数值计算研究了高层建筑地下室楼板模型及地下室外回填土约束作用对核心筒剪力墙计算结果的影响。研究表明,地下室楼板采用刚性假定不能真实地反映结构的受力状况,无论地下室外回填土的约束作用是否考虑,都会得出地下1层墙肢剪力突增的计算结果;而地下室楼板采用弹性壳元模拟,即便地下室外回填土的约束设定为无约束和水平刚性约束两种极端情况,地下1层核心筒剪力墙依然不会出现显著的剪力突变。  相似文献   
992.
总结了玻璃幕墙用硅酮结构密封胶常见的安全隐患,并以硅酮结构密封胶原材料性能安全指标出发,分析了国标、美标、欧标三大标准体系对硅酮结构密封胶性能指标要求的差异,着重介绍了欧标中六类环境老化因素对硅酮结构密封胶性能影响的试验方法,最后给出了关于国内硅酮结构密封胶标准未来发展方向的建议。  相似文献   
993.
对风荷载的特性进行了介绍,着重分析了其对桥梁结构的静力及动力作用效应,介绍了进行风荷载模拟所采用的方法,并分别计算了静风荷载及脉动风荷载对桥梁结构的影响,充分验证了风荷载对桥梁结构的动力作用不容忽视。  相似文献   
994.
指出在单层厂房柱下独立基础的设计中存在忽略基础上部受拉的问题,提出了可以按照素混凝土结构进行基础设计。按照规范及对基础的受力分析推导出了简单的判断公式。用该公式可以容易地判断出基础上部是否需要配置抗弯钢筋。  相似文献   
995.
A new high‐ultraviolet (UV)‐transmission silicone‐resin polymeric material was prepared via curing during hydrosilylation of tetramethyltetravinylcyclotetrasiloxane with tetramethylcyclotetrasiloxane by a liquid‐surface supernatant method, using a stepwise heating program to avoid spontaneous combustion of the reaction mixture. The relationships were investigated in detail between reactive groups, cross‐linking density, mechanical and UV‐transmission properties. For this purpose, UV transmittance and dynamic mechanical properties, respectively, of the silicone resin were measured with UV–visible spectrophotometry and dynamic mechanical thermal analysis. In addition, surface roughness was evaluated with an atomic force microscope as well as an interferometer. The curing process was monitored by Fourier transform infrared spectroscopy and rotational rheometry. The cyclic silicone oils were compared with linear ones in structure and product properties. The results indicated that stepwise temperature control during curing process was particularly indispensible due to the presence of active Si? H bonds, and that the silicone resin of high modulus, high UV transmittance (92.7%) and low surface‐roughness was largely homogeneous in cross‐linking points distribution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43308.  相似文献   
996.
Glucose‐sensitive and fluorescence copolymer micelles were designed and prepared via a combination of photoinitiated polymerization and enzymatic transesterification. The water‐soluble photoinitiator and emulsifier 2‐oxooctanoic acid self‐polymerized dimer molecules under UV irradiation were characterized by mass spectrometry. The fluorescence dye (9‐anthracene alcohol) and biocompatible hydrophilic chains [poly(ethylene glycol)] were introduced to the polymer chains during the photopolymerization and enzymatic transesterification processes. The as‐prepared copolymers were confirmed by 1H‐NMR spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and dynamic light scattering. The resulting copolymers exhibited excellent glucose sensitivity and stability against protein. The optical fluorescence properties of the copolymer micelles were investigated with fluorescence spectrophotometry, fluorescence microscopy, and confocal laser scanning microscopy. Because of the amphiphilic feature, the micelles could be self‐assembled and used to load insulin. The controlled release of insulin was evaluated and was triggered by glucose in vitro. This study provided a new strategy for fabricating functional carriers as self‐regulated insulin‐release systems. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43026.  相似文献   
997.
Thomsen–Friedenreich (TF) antigen is an important tumor‐associated carbohydrate antigen. Its low immunogenicity, however, limits its application in the development of anticancer vaccines. To solve this problem, several N‐acyl‐modified TF derivatives were synthesized and conjugated with carrier protein CRM197 (a mutated diphtheria toxoid cross‐reactive material). The immunological results in BALB/c mice demonstrated that these modified TF antigen conjugates could stimulate the production of higher titers of IgG antibodies that cross‐reacted with native TF antigen. These glycoconjugates showed strong lymphocyte proliferative response, suggesting that they can induce cellular immunity. Furthermore, the elicited antisera reacted strongly with TF‐positive tumor cells (4T1). In particular, the N‐monofluoroacetyl‐modified TF conjugate 4 ‐CRM197 showed the strongest complement‐dependent cytotoxicity effect against 4T1 cells, implying the potential of this glycoconjugate as an anticancer vaccine.  相似文献   
998.
999.
Emerging studies show that long noncoding RNAs (lncRNAs) have important roles in carcinogenesis. lncRNA ZEB1 antisense 1 (ZEB1-AS1) is a novel lncRNA, whose clinical significance, biological function, and underlying mechanism remains unclear in glioma. Here, we found that ZEB1-AS1 was highly expressed in glioma tissues, being closely related to clinical stage of glioma. Moreover, patients with high ZEB1-AS1 levels had poor prognoses, with the evidence provided by multivariate Cox regression analysis indicating that ZEB1-AS1 expression could serve as an independent prognostic factor in glioma patients. Functionally, silencing of ZEB1-AS1 could significantly inhibit cell proliferation, migration, and invasion, as well as promote apoptosis. Knockdown of ZEB1-AS1 significantly induced the G0/G1 phase arrest and correspondingly decreased the percentage of S phase cells. Further analysis indicated that ZEB1-AS1 could regulate the cell cycle by inhibiting the expression of G1/S transition key regulators, such as Cyclin D1 and CDK2. Furthermore, ZEB1-AS1 functioned as an important regulator of migration and invasion via activating epithelial to mesenchymal transition (EMT) through up-regulating the expression of ZEB1, MMP2, MMP9, N-cadherin, and Integrin-β1 as well as decreasing E-cadherin levels in the metastatic progression of glioma. Additionally, forced down-regulation of ZEB1-AS1 could dramatically promote apoptosis by increasing the expression level of Bax and reducing Bcl-2 expression in glioma. Taken together, our data suggest that ZEB1-AS1 may serve as a new prognostic biomarker and therapeutic target of glioma.  相似文献   
1000.
多尾鳍仿生推进器多推进模式运动仿真研究   总被引:1,自引:0,他引:1  
谢鸥  颜钦 《机床与液压》2016,44(5):158-161
提出了一种新型水下仿生推进器,采用多尾鳍协调驱动方式实现了鱼类波动推进模式和水母射流推进模式的有机复合,建立了多尾鳍波动-射流推进的运动学模型,着重利用计算流体动力学方法对多尾鳍波动-射流推进运动进行了仿真分析。研究结果表明:在特定运动参数下,多尾鳍波动推进模式能提供持续均匀的推进力,游动稳定性好;而射流推进模式,能产生瞬间的大推进力,加速性能好。研究内容为进一步探索多模式推进理论提供了依据。  相似文献   
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