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排序方式: 共有231条查询结果,搜索用时 15 毫秒
1.
为了有效改善大跨度桥梁中管翼缘焊接箱型截面构件的耐久性的问题,提出采用耐候钢代替普通钢的管翼缘箱型截面梁。同时,为了研究耐候钢管翼缘焊接箱型截面构件填充混凝土后在全熔透和部分熔透条件下的单轴承载力性能,开展了焊接矩形截面在三种不同焊缝熔深下的耐候钢管混凝土截面轴压短柱试验研究。分别测试每个试件在单轴压力作用下的静态应变、动态应变,以及竖向位移和侧向位移。对比构件承载力的试验结果及理论分析结果,得出不同熔深下焊接箱型截面管翼缘组合构件的承载力性能。研究结果表明:1)耐候钢管翼缘焊接箱型截面构件的全熔透焊缝承载力高于部分熔透焊缝承载力。2)全熔透试件开裂时的竖向位移较部分熔透试件的位移值大,而不同熔深下构件的横向位移测点L4随轴压荷载的增大而有增加,L3测点横向位移规律不明显。3)不同耐候钢管翼缘焊接箱型截面构件横向整体受拉,局部在顶部角部位置受压。构件的混凝土内部和钢板表面应变情况复杂,规律不明显。 相似文献
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本法采用乙醇水溶解试样,以经过处理的无钾,钠离子聚醚鸩元醇作为基体,配制标准样品,用火焰光度法检测聚醚多元醇中间品的钾(钠)离子的含量。由于样品处理简单,应用浓度直读取数据,可快速准确地测定试样,适用于聚醚多元醇生产过程中间品的检验。 相似文献
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Rong Yuan Zhujun Jing Luonan Chen 《Automatic Control, IEEE Transactions on》2003,48(2):344-348
We formulate a model for hybrid dynamical systems with delay, which covers a large class of delay systems. Under several mild assumptions, we establish sufficient conditions for uniform asymptotic stability of hybrid dynamical systems with delay via a Lyapunov-Razumikhin technique. To demonstrate the developed theory, we conduct stability analyses for delay sampled-data feedback control systems including a nonlinear continuous-time plant and a linear discrete-time controller. 相似文献
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Chaowei Wen Zhujun Tian Lan Li Tongke Chen Huajian Chen Jichen Dai Zhenzhen Liang Shumei Ma Xiaodong Liu 《International journal of molecular sciences》2022,23(23)
Protein arginine methyltransferase 5 (PRMT5) is an epigenetic regulator which has been proven to be a potential target for cancer therapy. We observed that PRMT5 underwent alternative splicing (AS) and generated a spliced isoform PRMT5-ISO5 in hepatocellular carcinoma (HCC) patients after radiotherapy. However, the regulatory mechanism and the clinical implications of IR-induced PRMT5 AS are unclear. This work revealed that serine and arginine rich splicing factor 3 (SRSF3) silencing increased PRMT5-ISO5 level, whereas heterogeneous nuclear ribonucleoprotein H 1 (HNRNPH1) silencing reduced it. Then, we found that SRSF3 and HNRNPH1 competitively combined with PRMT5 pre-mRNA located at the region around the 3′- splicing site on intron 2 and the alternative 3′- splicing site on exon 4. IR-induced SRSF3 downregulation led to an elevated level of PRMT5-ISO5, and exogenous expression of PRMT5-ISO5 enhanced cell radiosensitivity. Finally, we confirmed in vivo that IR induced the increased level of PRMT5-ISO5 which in turn enhanced tumor killing and regression, and liver-specific Prmt5 depletion reduced hepatic steatosis and delayed tumor progression of spontaneous HCC. In conclusion, our data uncover the competitive antagonistic interaction of SRSF3 and HNRNPH1 in regulating PRMT5 splicing induced by IR, providing potentially effective radiotherapy by modulating PRMT5 splicing against HCC. 相似文献
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文章在分析传统古筝的材料、流派、颜色、形状、装饰、制作等方面的基础上,进行了古筝外观的文化探讨。提出了古筝外观改革需要重点考虑的三个方面即古筝的使用人群、古筝的"流行化"倾向、古筝与周边环境的和谐。进行了古筝外观改革的实践尝试,提出了外观改造的具体方案。 相似文献
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There is no common accepted way for calculating the valve power loss of modular multilevel converter (MMC). The method based on analytical calculation is inaccurate to address the switching power loss while the method based on detailed electro-magnetic simulation is of low speed. To solve this problem, an accurate valve power loss evaluation method of MMC based on the detailed equivalent simulation model of MMC is proposed. A fast power loss evaluation method is then proposed by linking the PSCAD/EMTDC and Matlab files. Detailed valve power loss analysis of a 201-level 500MW MMC operating at 50Hz~1000Hz is then presented. Relationship between the valve power loss, power transfer level and operating frequencies are presented and fitted. Research results of this paper can be used as guidance for the application of medium and high frequency MMC. 相似文献
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Zehong Wang Zhujun Rao Yizhen Zhan Tianqi Hao Wei Wang Dan Yu 《Coloration Technology》2016,132(6):481-487
Polyimide fabric, as a high‐performance fabric, possesses advantageous properties, such as outstanding thermal stability and chemical resistance, but has poor dyeability. In this paper, polyimide fabric was dyed successfully with disperse dyes by high‐temperature and high‐pressure dyeing in the presence of a swelling agent and auxiliaries. Under optimal dyeing conditions, it is pretreated with NaOH 6 g l?1 and dyed with disperse dyes 5% o.w.f., NaCl 1 m , benzyl alcohol 60 ml l?1 at 135 °C for 45 min to obtain a satisfactory colour yield with good washing fastness and dry rubbing fastness with 93.3% strength retention. The experimental results demonstrate that the Nernst adsorption isotherm is a favourable model for polyimide fabric dyeing with disperse dyes. 相似文献
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