太阳活动22周峰年日地系统整体行为研究计划

<正> 在1985年,中国科学院计划局成立天文、空间科学和地球科学综合发展战略研究组。经过一年多的工作,该组的专家们提出进行日地系统整体行为研究的建议,该建议得到了太阳物理、空间物理及地球科学领域广大科技工作者的支持,中科院机关的许多管理专家也表示赞成。中科院院长周光召教授建议加强在太阳峰年期间的跨学科相关研究。太阳活动22周日地系统整体行为研究被列为中国科学院“七•五”重点项目之一,

板壳断裂力学

本书阐明了板壳断裂理论的基础。论证了Reissner型板壳断裂理论的科学性、经典板壳断裂理论的缺陷及在一定范围内仍具有的实用价值；介绍了作者所创意的研究Reissner型板壳断裂纹尖端场的方法等。

目录

Experimental study of nonlinear switching characteristics of conventional 2×2 fused tapered couplers

The nonlinear switching characteristics of fused fiber directional couplers were studied experimentally. By using femtosecond laser pulses with pulse width of 100 fs and wavelength of about 1550 nm from a system of Ti:sapphire laser and optical parametric amplifier (OPA), the nonlinear switching properties of a null coupler and a 100% coupler were measured. The experimental results were coincident with the simulations based on nonlinear propagation equations in fiber by using super-mode theory. Nonlinear loss in fiber was also measured to get the injected power at the coupler. After deducting the nonlinear loss and input efficiency, the nonlinear switching critical peak powers for a 100% and a null fused couplers were calculated to be 9410 and 9440 W, respectively. The nonlinear loss parameter P_(N) in an expression of α_(NL)=αP/P_(N) was obtained to be P_(N)=0.23 W.

大蹼铃蟾抗菌肽22 对膀胱癌细胞株HLA-ABC以及DR表达影响的对照实验研究

　目的　探讨大蹼铃蟾抗菌肽22 (Maximin22) 对膀胱癌 细胞株HLA2DR 及HLA2ABC 表达的影响, 并与TNF2α、 IFN2α进行比较。方法　采用肿瘤细胞培养方法,流式细胞 仪检测各实验样品对膀胱癌细胞株T24 、BIU287 、SCaBER 的HLA2DR 及HLA2ABC 表达的影响。结果　Maximin22 对 不同的膀胱癌细胞株在小剂量下即有抑制作用,并呈剂量相 关性,各实验样品未见对各膀胱癌细胞株的HLA2DR 表达 有影响,Maximin22 、TNF2α对HLA2ABC 的表达均无影响; IFN2α则对HLA2ABC 的表达有上调作用。结论　Maximin2 2 、TNF2α抗癌机制与提高肿瘤细胞HLA2DR、ABC 的表达无 关, IFN2α可通过提高肿瘤细胞HLA2ABC 的表达提高T 细 胞对膀胱肿瘤的识别杀伤能力。

Isolation and preliminary characterization of a 22-kDa protein with trypsin inhibitory activity from toad Bufo andrewsi skin

A novel trypsin inhibitor termed BATI was purified to homogeneity from the skin extracts of toad Bufo andrewsi by successive ion-exchange, gel-filtration and reverse-phase chromatography. BATI is basic single chain glycoprotein, with apparent molecular weight of 22 kDa in SDS-PAGE. BATI is a thermal stable competitive inhibitor and effectively inhibits trypsin's catalytic activity on peptide substrate with the inhibitor constant (K-i) value of 14 nM and shows no inhibitory effect on chymotrypsin, thrombin and elastase. The N-terminal sequence of BATI is EKDSITD, which shows no similarity with other known trypsin inhibitors. (c) 2005 Elsevier Ltd. All rights reserved.

基于光纤阵列的2×2机械式光开关

于AD批量导入至AEzhangdi

High-performance 2 mm gate width GaNHEMTs on 6H-SiC with output power of 22.4 W @ 8 GHz

Optimized AlGaN/AlN/GaN high electron mobility transistors (HEMTs) structures were grown on 2-in semi-insulating (SI) 6H-SiC substrate by metal-organic chemical vapor deposition (MOCVD). The 2-in. HEMT wafer exhibited a low average sheet resistance of 305.3 Omega/sq with a uniformity of 3.85%. The fabricated large periphery device with a dimension of 0.35 pm x 2 nun demonstrated high performance, with a maximum DC current density of 1360 mA/mm, a transconductance of 460 mS/mm, a breakdown voltage larger than 80 V, a current gain cut-off frequency of 24 GHz and a maximum oscillation frequency of 34 GHz. Under the condition of continuous-wave (CW) at 9 GHz, the device achieved 18.1 W output power with a power density of 9.05 W/mm and power-added-efficiency (PAE) of 36.4%. While the corresponding results of pulse condition at 8 GHz are 22.4 W output power with 11.2 W/mm power density and 45.3% PAE. These are the state-of-the-art power performance ever reported for this physical dimension of GaN HEMTs based on SiC substrate at 8 GHz. (c) 2008 Elsevier Ltd. All rights reserved.