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331.
332.
液体—结构—桩基—土体系相互作用动力分析 总被引:4,自引:0,他引:4
将工程中常用的密集桩基体系模拟为正交各向异性弹性体,采用样条函数表征桩基和土的位移,不但满足圆柱体柱坐标的极点条件,且待定系数少、边界条件容易处理,用自编专用程序SXJG在微机上对支承在桩基上的储液罐这一液体-结构-桩基-土体系进行了动力分析,得到了一些规律性的结果。 相似文献
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334.
详细研究了460.7nm锶原子共振滤波器中内部光子转换效率随氩缓冲气压和温度的变化关系,并研究了滤波器的通频带随氩气压的变化关系及响应时间随温度的变化关系. 相似文献
335.
本文以Teflon-FEP薄膜在常温下的空气中,加控制栅极前后进行电晕注极为例,研究了样品膜的注极效果。栅极的引入,不但能控制样品的表面电位值,而且使得样品的表面电荷分布更加均匀. 注极参数的变化将影响注极结果.实验表明:针极电压,注极时间,栅极电压,栅网孔径,针-栅间距和栅-膜间距各注极参数直接影响薄膜的表面电位值和表面电荷的分布.最后导出对Teflon-FEP薄膜的最佳注极参数,这些参数在同样条件下对其它聚合物也是适用的. 相似文献
336.
Ding H Wu X Boström H Kim I Wong N Tsoi B O'Rourke M Koh GY Soriano P Betsholtz C Hart TC Marazita ML Field LL Tam PP Nagy A 《Nature genetics》2004,36(10):1111-1116
PDGF-C is a member of the platelet-derived growth factor (PDGF) family, which signals through PDGF receptor (PDGFR) alphaalpha and alphabeta dimers. Here we show that Pdgfc(-/-) mice die in the perinatal period owing to feeding and respiratory difficulties associated with a complete cleft of the secondary palate. This phenotype was less severe than that of Pdgfra(-/-) embryos. Pdgfc(-/-) Pdgfa(-/-) embryos developed a cleft face, subepidermal blistering, deficiency of renal cortex mesenchyme, spina bifida and skeletal and vascular defects. Complete loss of function of both ligands, therefore, phenocopied the loss of PDGFR-alpha function, suggesting that both PDGF-A and PDGF-C signal through PDGFR-alpha to regulate the development of craniofacial structures, the neural tube and mesodermal organs. Our results also show that PDGF-C signaling is a new pathway in palatogenesis, different from, and independent of, those previously implicated. 相似文献
337.
JiangCong-sheng WangTao DingQing-jun HuangShao-long WangFa-zhou GengJian HuShu-guang 《武汉大学学报:自然科学英文版》2004,9(3):348-352
The influence of polymer addition on microstructure, performance and mechanical properties of lightweight aggregate concrete was investigated. It was found that the addition of polymer improved the performance and mechanical properties of lightweight aggregate concrete. It was ascertained that the modification of microstructural uniformity and densification with the addition of polymer is responsible for the enhancement of mechanical properties.With respect to compressive strength and bending strength, the lightweight aggregate concrete added with 13% ethylene-acetate ethylene interpolymer ( EVA ) exhibits preferred mechanical properties. 相似文献
338.
GU Zhaoyan LIU Qiang XU Bing HAN Jiamao YANG Shiling DING Zhongli & LIU Tungsheng Institute of Geology Geophysics Chinese Academy of Sciences Beijing China Correspondence should be addressed to Gu Zhaoyan 《科学通报(英文版)》2003,48(12):1271-1276
Two modes of photosynthesis predominate in terres-REPORTS trial plants: the C3 and C4 modes[1]. The C3 mode is used by all of trees, bushes, and cold season grasses. The C4 mode is used by the most of tropical and warm season grasses. They are disadvantaged relative to C3 plants at high CO2/O2 ratios because of the additional energy ex-pense needed to concentrate CO2 in the bundle-sheath cells. At low CO2/O2, however, C4 plants can achieve a relatively high quantum yield by suppressin… 相似文献
339.
DING Bin WANG Hongmei YI Long CHENG Peng LI Licun ZHAI Yuping LIAO Daizheng YAN Shiping & JIANG Zonghui Department of Chemistry Nankai University Tianjin China Correspondence should be addressed to Cheng Peng or Liao Daizheng 《科学通报(英文版)》2003,48(22):2446-2449
Spin-crossover complexes are of great interest to the scientists because of their potential application in molecular-based electronic devices. Some octahedral metal compounds with 3dn (4 ≤ n ≤ 7) configuration can induce a spin state conversion through a fine tuning condition (temperature, pressure, light irradiation, etc.). If the conversion occurs reversibly with a hystersis loop and color change, it will make the system possessing memory effect. The memory effect can be magnified and the … 相似文献
340.
DINGJie ZHUTong 《科学通报(英文版)》2003,48(21):2267-2276
Fine particles play an important role in the atmosphere. Research on heterogeneous reactions on the surface of fine particles is one of the frontier areas of atmospheric science. In this paper, physical and chemical characteristics of fine particles in the atmosphere and the interactions between trace gases and fine particles are described, methods used in heterogeneous reactions research are discussed in detail, progress in the study of heterogeneous reactions on the surface of fine particles in the atmosphere is summarized, existing important questions are pointed out and future research directions are suggested. 相似文献