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991.
荷兰建筑师库哈斯设计的央视总部方案,从2002年中标开始,就不断引起争论。2004年库氏出版了《Content》一书,并未引起国人太多注意。2009年元宵节央视配楼大火,公众对央视总部开始重新关注,发现库哈斯在《Content》中表达的设计“理念”竞是赤裸裸的色情,央视“色情门”事件遂成为网上议论热点,库氏被迫发表了自辩声明,争论更加激烈,网文数以百计,影响至于国内外媒体,至8月下旬达到高峰,至今持续未休。本文对整个事件过程作了比较详尽的记述,提出了自己的观点。 相似文献
992.
Garmin GPS手持导航仪地图功能的应用 总被引:1,自引:0,他引:1
Garmin GPS手持导航仪是目前使用最为广泛的手持导航仪,在石油勘探导航定位中发挥了很大的作用,本文主要针对Garmin GPS手持导航仪所存储的航点、地图以及等高线等方面进行了研究分析,使用了多种方法将更多的定位数据存储于导航仪中,更加方便了野外地震采集海量导航数据的需求。 相似文献
993.
Cheng Guan Lim 《Quantum Electronics, IEEE Journal of》2009,45(5):523-530
Injection of transverse-magnetic polarized 1.55- mum pump light pulses having an excessively high intensity into heavily-doped AlAsSb-InGaAs-AlAs coupled-double-quantum-well optical waveguides causes a large amount of electrons in the ground state of the subbands in the conduction band to transit to the excited state and results in bandgap shrinkage as well as a large amount of vacant sites in the ground state. Consequently, the simultaneously injected continuous-wave transverse-electric polarized 1.54- mum probe light is absorbed by the valence-band electrons through two-photon absorption (TPA) and transit to the vacant sites in the ground state of the subbands in the conduction band. As a result, the probe power is reduced instantaneously but recovers at a time constant in the order of 10-10s. A theoretical evaluation of the effect of the above intersubband-pump-assisted TPA of the probe light shows that the pump-induced net refractive-index change in these devices is reduced by 50% when intersubband absorption and ISB-pump-assisted TPA of the probe light are of equal strength. Characterization of the TPA in these devices indicates that these devices have a TPA coefficient of 25 cm/GW. 相似文献
994.
本文分析了电机转子部件保证质量的重要因素.介绍了利用转子动平衡机对转子校平衡所需的重要工装器具:转子动平衡轴套.通过对其改进从而提高工作效率与找正精度. 相似文献
995.
Moon Gi Cho Sung K. Kang Sun-Kyoung Seo Da-Yuan Shih Hyuck Mo Lee 《Journal of Electronic Materials》2009,38(11):2242-2250
The effects of the addition of Zn to Sn-0.7Cu solders are investigated. The study is focused on the interfacial reactions,
microstructures, and mechanical properties after reaction with Ni-P under bump metallurgies (UBMs). The Zn contents in Sn-0.7Cu-xZn are varied as 0.2, 0.4, and 0.8 (in wt.% unless otherwise specified). In the reaction with Ni-P UBM during thermal aging
at 150°C for 1000 h, (Cu,Ni)6Sn5 intermetallic compounds (IMCs) are formed at the Sn-0.7Cu/UBM interface, whereas Zn is incorporated into IMCs to form (Cu,Ni,Zn)6Sn5 in the Zn-doped solders. As the Zn content increases, the interfacial IMC thickness is reduced. A total reduction of about
40% in IMC thickness was observed for the 0.8% Zn-doped Sn-Cu. The same IMC particles are also observed in the matrix of each
solder. In Sn-0.7Cu, (Cu,Ni)6Sn5 particles are coarsened during aging, while (Cu,Ni,Zn)6Sn5 particles in the Zn-added solders are less coarsened and remain much smaller than (Cu,Ni)6Sn5. The growth rate of (Cu,Ni)6Sn5 during thermal aging is significantly suppressed by the addition of Zn. Consequently, after reaction with Ni-P UBM, the Zn-doped
solders exhibit a thermally stable microstructure as measured by hardness and shear strength. 相似文献
996.
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
997.
998.
Xiaoxu Huo Xiangyi Peng Wei Liu Xiaoliang Mo Guorong Chen Shanli Wang Junhao Chu 《Journal of Materials Science: Materials in Electronics》2013,24(7):2479-2484
CdTe films were prepared on Fluorine-doped tin oxide substrate by RF magnetron sputtering and close spaced sublimation (CSS) methods, respectively. These CdTe films were then treated with a wet CdCl2 heat process at different temperatures. The structural and optical properties of CdTe films were investigated by X-ray diffraction, scanning electron microscope and UV–Visible spectrophotometer. The results reveal that both types of CdTe films have a better crystalline and larger grain size after CdCl2 heat treatment. However, the (422) peak has a more preferential orientation than (511) peak after CdCl2 activation for CdTe films prepared by sputtering method, while these two peaks almost have the same intensity for CSS-prepared CdTe films. The transmittance of CdTe films prepared by CSS is apparently lower than sputtered CdTe films. Correspondingly, the efficiency of solar cells with CSS-prepared CdTe is 7.3, 2.6 % of sputtered CdTe films. 相似文献
999.
Tannin fraction from Ampelopsis grossedentata leaves tea (Tengcha) as an antioxidant and α‐glucosidase inhibitory nutraceutical
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Sheng Geng Yongsheng Chen Arshad Mehmood Abbasi Hanjun Ma Haizhen Mo Benguo Liu 《International Journal of Food Science & Technology》2016,51(12):2692-2700
Leaf of Ampelopsis grossedentata is a new resource of functional foods with healthful properties. Antioxidant and α‐glucosidase inhibitory activities of water extract (made in the style of drinking), tannin fraction (TF) and dihydromyricetin (DMY) from A. grossedentata leaves were evaluated. The main component of TF was identified as gallotannins. DPPH and ABTS radical scavenging activities and reducing power of TF were superior to those of water extract, however, inferior to those of DMY. In no PBS wash protocol of cellular antioxidant activity assay, DMY and TF exhibited similarly, while in PBS wash protocol, the value of TF was higher than that of DMY. In addition, TF possessed the highest α‐glucosidase inhibitory activities (IC50 = 1.94 μg mL?1), followed by water extract (IC50 = 23.10 μg mL?1) and DMY (IC50 = 72.21 μg mL?1). The strong α‐glucosidase inhibitory activity of TF may attribute to the binding capacity to enzymes, as confirmed by fluorescence analysis. 相似文献
1000.
We present a discrete time single-server two-level mixed service polling systems with two queue types,one center queue and N normal queues.Two-level means the center queue will be successive served aft... 相似文献