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991.
考虑横向剪切效应的竹材层合板弯曲变形 总被引:7,自引:0,他引:7
用层梁经典理论,一阶剪切变形理论以及有限单元法分别计算了竹材层合板梁的弯曲变形,为验证理论分析与数值计算结果是否合理,对实际结构变形进行了测定。结果显示,竹材层合板梁在跨高比较小时具有十分显的的横向剪切交 ,一阶剪切变形理论与有限单元法均能足够精确地反映含有剪切效应的梁的弯曲变形,横向剪切效应很小时,经典理论的解与实际情况的符合程序优于一阶剪切变形理论。 相似文献
992.
石油化工信息化战略与组织模式再造 总被引:3,自引:1,他引:2
信息技术迅速发展及其在应用领域的渗透与拓展,使我国国民经济和社会信息化进程加快,石油化工信息化已呈现出必然趋势。基于我国石油化工信息化战略,研究组织模式再造的动因和趋势,并提出一种新型组织模式-核心功能型组织模式。同时,探讨核心功能型组织模式同企业核心能力和竞争优势的形成的关系。 相似文献
993.
The stripe disease-specific protein (SP) encoded by the rice stripe virus (RSV) was successfully used as a localization signal
of the virus in its vector, the small brown lanthopper,Laodelphax striatellus Fallen. Immunogold particles in large numbers were detected in various parts of the viruliferous females: the ovum, surface
of chorion, the midgut lumen, and the columnar cells. Whereas there was none of these particles in the non-viruliferous females
and males, and testis of viruliferous males. Endosymbionts (mycetocytes) were abundant, harboring ovaries of both viruliferous
and non-viruliferous females, but none in the testis of males. The results provided us with the direct proof that RSV is a
ciruculative and propagative plant virus and it was transovarially transmitted alongside with endosymbionts of its vector.
Therefore, we deem it a nice lead for future studies on the mechanism of RSV transmission and functioning of its viral proteins. 相似文献
994.
Tingfang Shen 《科学通报(英文版)》2001,46(21):1842-1845
Based on the analysis of three void damage variety models, this note presents (i) a method that regards the void content as
a damage variation of the grain and (ii) a geometric model for micro-unit of void damage. Equations of the void damage variety
containing void content are analyzed. This work is focused on the measurement of internal damage level and the damage variety
estimation is directly related to the life predication in the practical engineering applications. Nowadays, the critical service
life of the solid grain/polymers is usually presumed at domestic and international level. The strength or strain reduction
of 20% or the stabilizer consumption of 50% is generally regarded as a critical storage life of the solid grain/polymers,
and the service life is predicted by the extrapolation method on Anhenius formula. The applications, however, show that the
above method is unreliable and has significant errors. With the aid of the discontiguous automatic measuring device of real
time volume deformation and void content, the master curve of void damage variety, the storage service life and the surplus
life of a solid rocket grain are obtained. Since the critical storage life has been measured, and the accuracy of the service
life prediction has been greatly increased. It is a novel ideal and a break-through technique. 相似文献
995.
Isotopic composition characteristics and identification of immature and lowmature oils 总被引:1,自引:0,他引:1
Isotopic composition characteristics and the significance of immature and low-mature oils are first systematically discussed.
The carbon isotopes of the whole oil can be divided into two groups, one has δ13C main peak values ranging from -30‰ to -29 and the other from -27‰ to-25‰, they are related to lacustrine and salt-lake facies
or swamp facies, respectively. The carbon isotopic fractionation among different group components is relatively small, usually
less than 2‰ and the biggest difference in fractionation often occurs between saturated and aromatic fractions. Their δD values
vary between -180‰ and -130‰ The main peak of their δD values concentrates between -170‰ and -150‰, suggesting a domination
of lacustrine fades. However, the secondary peak ranges from -160‰ to -150‰, showing a frequent salinization of paleo-water
bodies. The average δ13C values of the methane vary between -50‰ and -52‰, about 10‰ lighter than those of mature oils. There is a relatively good
correlationship between immature and low-mature oils and their source rocks in carbon isotopic compositions of group fractions
and monohydrocarbons; moreover, compared with the source rocks of mature oils, that of immature oils is often relatively depleted
in13C, which is one of the characteristics of immature oils, differing from those of mature oils. 相似文献
996.
硼系表面活性剂复配性能的研究 总被引:6,自引:0,他引:6
以二乙醇胺与硼酸酯化合成硼酸酯(DEAB),再与1-溴十二烷烷基化合成了一类新型含硼两性表面活性剂(RDEAB)。用二元表面活性剂溶液的热力学,研究了RDEAB-AES、RDEAB-AEO9 2种水溶液的混合体系胶束中表面性剂分子间相互作用参数β^m和胶束的组成,2种混合体系的β^m值分别为:-6.47、-3.46。 相似文献
997.
Shen Xianrong Ji Dongmei Hu Youqing Jia Fuxing Deng Xinxian Wang Ling Chu Zhiyong Jiang Dingwen Lei Chengxiang Huang Jiansheng Hu Xinran Ren Daming 《科学通报(英文版)》2001,46(24):2037-2042
Sequences encoding PF4 (58–70) and TSP1 (429–459) were linked to yield a single gene TSF which encodes the fuse-protein of TSF. The gene was cloned into a pGEX-2T expression vector to generate a protein GST-TSF, which was strongly expressed inE. coli. The purified GST-TSF was degraded with thrombin to generate the protein TSF. With the methods of MTT and wound repair assay, the effects of TSF on the proliferation and migration of EC were detected, respectively. The results showed that TSF significantly suppressed BAEC proliferation and migration in a dose-dependent manner. The fuse protein GST-TSF, and the peptides PF4 (58–70) and TSP1 (429–459) also inhibited BAEC proliferation and migration, respectively, but their inhibition rates were not as high as TSF. Using the CAM assay, it was shown that TSF, GST-TSF, PF4 (58–70) and TSP1 (429–459) inhibited angiogenesis in chick CAM potentially, the effect of TSF was the highest.In vivo, the growth of Lewis lung carcinoma was potently inhibited by TSF treatment, and the inhibition rate was 68.75% at a dose of 1.00 μmol/kg · d. These findings suggest that the design on TSF gene was successful, and TSF with its anti-angiogenic and anti-tumor activity, should be a useful source of the inhibitor. 相似文献
998.
The local distribution of preferred orientation and misorientation in TiN whiskers in TiNw-AINp/A1 composite system is investigated using backscattering electron diffraction combined with a scanning electron microscope. These preliminary results demonstrate the utility of this new automated technique for characterizing local textures in composite materials using backscattering electron diffraction. The composite investigated comprises TiN whiskers in a polycrystalline aluminum matrix. The local textures of samples before and after deformation were measured. The misorientation distributions show a breakdown of the monocrystal of TiN whisker in the deformed composite material relative to the starting material and an increase in small angle misorientations. 相似文献
999.
利用自动控制发酵设备,首先进行分批发酵实验摸索恶臭假单胞菌PseudomonasJS-01的生长与代谢的基本规律,然后采用补料分批发酵的方法限制生长基质的浓度,测定了一系列(C 相似文献
1000.
要分析火电机组高压加热器泄漏后,热力系统的变化情况,必须首先知道热力系统流体网络内工质压力和质量流量的变化情况。为了获得以上数据,应用流体网络理论建立了某机组热力系统流网模型,经验证建模方法可行。应用该建模方法,建立了3号高压加热器泄漏后的热力系统流网模型。通过模型求解,得到了3号高压加热器泄漏后工质压力和质量流量分布情况,分析了高压加热器泄漏后,热力系统流体网络的变化。 相似文献