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961.
Tong Wang Earl G. Hammond Walter R. Fehr 《Journal of the American Oil Chemists' Society》2001,78(11):1139-1144
Soybeans with modified saturated fatty acid compositions sometimes have lower seed germination rate or other undesirable agronomic
traits. To determine if seed germination could be related to the melting transitions of their lipids, triacylglycerols (TAG)
and phospholipids (PL) from soybeans with a wide range of saturated fatty acid compositions were examined by differential
scanning calorimetry. The melting transition temperatures of both TAG and PL increased with increasing palmitate and stearate
percentages. The mean melting points of the various lipids calculated on the basis of the melting points of their fatty acids
correlated with the observed transition temperatures. Increased lipid saturation and elevated phase transition temperatures
may have contributed to the reduced germination and seedling growth rates of these modified seeds. 相似文献
962.
一种简易实用的开口剪切腹板有限元建模方法 总被引:1,自引:0,他引:1
研究含开口剪切腹板结构简易的有限元建模技术,提出当量厚度的有限元建模方法,给出内含椭圆形开口以及长方形和弧形组合开口腹板的当量厚度计算式.该计算式考虑腹板形心与开口中心不重合及开口边缘有加强件.为了验证文中提出的当量厚度有限元建模方法的正确性,采用MSC.Nastran分别对含两种开口墙腹板的盒段进行有限元建模分析,并分别与常规的网格细化的有限元建模分析结果进行比较.结果表明,所给出的当量厚度建模方法与常规网格细化的建模方法吻合很好,相对误差不大于2.0%,验证了所提出建模方法的正确性和有效性. 相似文献
963.
964.
WeiLi Jian-Guo Guan Wei Wang Guo-Xiu Tong Xi-An Fan 《Materials Chemistry and Physics》2009,118(2-3):496-500
Hollow microspheres of hematite (α-Fe2O3) were prepared by a simple hydrothermal treatment of ferrous ammonium sulphate hexahydrate ((NH4)2Fe(SO4)2·6H2O) aqueous solution without any surfactants and additives at 180–200 °C. The products were characterized by XRD, FE-SEM and TEM. The results show that α-Fe2O3 hollow microspheres are about 1 μm in diameters and are composed of α-Fe2O3 nanoparticles with a diameter range from 50 nm to 150 nm. The effects of reaction parameters such as reaction time, temperature and [(NH4)2Fe(SO4)2·6H2O] on the morphology of the final product were investigated. A potential formation mechanism of α-Fe2O3 hollow microspheres was also proposed, where the intermediate, urchin-like goethite, served as a sacrificial template for the formation of hollow structure. The reaction parameters-depended morphologies of the final products consisted well with the proposed formation mechanism. 相似文献
965.
随着计算机技术的发展,数字技术被广泛地应用到影视制作当中,增强并完善了影视后期制作的功能,尤其满足了大规模制作的需求。数字技术已经开始对影视制作的流程本身进行改造,如媒体资产管理系统。本文重点分析了不同时期影视后期制作的自身特征,并根据目前影视制作的需求趋势讨论了影视后期制作系统的发展趋势。 相似文献
966.
Yu-Ting Wang Tien-Chen Hu Chi-Jia Tong Ming-Tzer Lin 《Microsystem Technologies》2012,18(11):1903-1908
This paper reports a novel full-range vacuum pressure sensing device, capable of exceeding the sensing range of most gauges and reducing the volume by a factor of 10. The proposed device gauges the free decay rate of a micro-cantilever beam deflected using electrostatic force and measurements of capacitance are used to determine the free decay rate of the sensing beam with respect to deflection force and vacuum pressure. This novel design enables the full-range measurement of vacuum pressure from 0.2 to 1?×?10?8?torr. The trapezoidal micro-cantilever beam provides uniform in-plane stress across the surface of the beam, while a thick square plate connected to the trapezoid beam serves as a proof mass and receiver of electrostatic force. Results demonstrate that the free decay rate of the deflected beam is linearly proportional to vacuum pressure. The decay time constant was 0.69?s under low vacuum and 42.56?s under high vacuum. In addition, a change in vacuum pressure of one torr resulted in a change of 47.6 (1/s) in the decay rate. This rapid response to changes in pressure demonstrates the high degree of sensitivity demonstrated by the device. The proposed device represents a considerable advancement in the development of miniature full-range pressure gauges as well as the applicability of micro-electromechanical systems. 相似文献
967.
968.
In this work, electrospray technique combined sol-gel method was used to prepare porous TiO2 film. X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD), and Scanning Electron Microscope (SEM) analyses were conducted to examine the chemical composition, phase structure, and surface morphology of the sprayed TiO2 film. After calcined at 450℃ in air atmosphere for 2 h, mesoporous TiO2 nano-spheres clusters were formed on the surface of silicon wafer and the average size of nano-spheres was 250 nm. Ti presented as Ti 4+ oxidation state in TiO2 film, and the TiO2 film exhibited the anatase phase. The sprayed porous TiO2 films were employed as photocatalyst to degrade organic phosphorus in water samples. Compared with the TiO2 film prepared by Sol-Gel spin-coating method, the porous TiO2 film deposited by electrospray combined sol-gel method showed higher photocatalytic activity. 相似文献
969.
The mechanical behavior of graphene under various indentation depths, velocities, and temperatures is studied using molecular dynamics analysis. The results show that the load, elastic and plastic energies, and relaxation force increased with increasing indentation depth and velocity. Nanoindentation induced pile ups and corrugations of the graphene. Resistance to deformation decreased at higher temperature. Strong adhesion caused topological defects and vacancies during the unloading process. 相似文献
970.
Blends of a commercial atactic poly(vinyl alcohol) (a‐PVA) derived from vinyl acetate and κ‐carrageenan were prepared by mixing the aqueous solutions of both samples. Blend films prepared by casting were transparent. In the DSC curves of the blend films, the endothermic peaks shifted to lower temperature with an increase of the content of κ‐carrageenan. The Young's modulus and the strength at break increased with an increase of the content of a‐PVA. As the standing temperature of the blend solutions decreased, the gelation region increased also at high content of carrageenan. In the amorphous regions of blend films, a‐PVA and κ‐carrageenan were miscible. © 2001 Society of Chemical Industry 相似文献