Morphological Stability of Epitaxial Thin Elastic Films by Van Der Waals Force

The morphological stability of epitaxial thin elastic films on a substrate by van der Waals force is discussed. It is found that only van der Waals force with negative Hamaker constant (A < 0) tends to stabilize the film, and the lower bound for the Hamaker constant is also obtained for the stability of thin film. The critical value of the undulation wavelength is found to be a function of both film thickness and external stress. The charateristic time-scale for surface mass diffusion scales to the fourth power to the wavelength of the perturbation.

水位变化引起分层边坡滑坡的实验研究

通过对分层的边坡在水位变化时滑坡的模拟实验,考察了分层坡体的滑坡模式、坡体变形、破坏和渗流引起的滑坡,重点考察了水位涨落速度对坡体稳定的影响,以及坡面从产生张拉裂缝直到形成滑面的整个过程,并对这类滑坡中的现象给出了定性解释.最后用有限元对实验坡体进行了应力和位移的静力场分析,计算结果与实验结果基本一致.

关于国家自然科学基金生物力学学科优先资助领域的思考

国家自然科学基金项目L0922118

光纤光栅在金属锈蚀传感中的应用

介绍了一种基于光纤布拉格光栅（FBG）应变敏感特性的金属锈蚀传感器。该器件由光纤光栅、有预应力的钢弹簧和一些机械部件组合而成。组合后的弹簧处于压缩状态。在弹簧弹力的作用下，光纤光栅的峰值波长增长了3．213m。对该器件进行了加速腐蚀实验：将其放入盐酸环境中，逐日监测光纤光栅峰值波长的变化，发现峰值波长逐渐缩短，说明弹簧的弹性系数随着弹簧的锈蚀而逐渐减小。到弹簧锈蚀断裂，整个锈蚀过程持续了1315h，平均锈蚀速率约5μm／d。实验表明了该传感器在实际应用中的可能性。同时讨论了光纤光栅的温度效应及其他影响其实

星载激光测距仪的高精度时间间隔测量单元

高精度时间间隔测量单元(TIU)是星载激光测距仪的关键部件。基于现场可编程门阵列(FPGA)研制出了满足星载要求的高精度、高集成度时间间隔测量单元。该单元采用数字计数法结合数字延迟线插入法的技术,在0.5～10 km的测量距离范围内,时间分辨率为500 ps。通过地面检测,在全程范围内保持了良好的线性度,标准偏差小于270 ps。该单元同时具备测量脉冲回波宽度的能力,可以获取目标的脉冲展宽信息。由于单元选用的元器件都具有航天产品性能,因此其设计和技术指标可满足星载激光测距仪的应用。

毛乌素沙地油蒿与籽蒿种子萌发对光照的反应

油蒿(Artemisia ordosica)与籽蒿(Artemisia sphaerocephala)为毛乌素沙地的优势物种，广泛用于我国北方干旱、半干旱区的生态恢复。油蒿与籽蒿种子萌发对温度、水分等环境条件的反应已有较为明确的研究结果，但关于这两种蒿属植物种子萌发对光照反应的研究目前存在两种不同的结论，对飞播技术的改善造成一定影响。 影响油蒿与籽蒿种子萌发对光照反应的因素较多。如种源地、结实部位、种子颜色、种子保存方式与时间、实验条件、温度等。考虑种源地、种子保存时间与方式、结实部位及温度，从多方面系统研究油蒿与籽蒿种子萌发对光照的反应。结果表明当温度较低时(10:20C)，萌发率和萌发速率在黑暗条件下显著高于在光照条件下。采自榆林地区的种子萌发状况相对较差，萌发率和萌发速率在大多数情况下显著低于其他两地;各种源地上下部种子萌发率有一定差异，大多数结实部位为上部的种子最终萌发率和萌发速率高于下部的种子;保存几周的种子萌发率变化不大，但在温度较高和较低时，随着种子保存时间的延长，萌发率下降较快，而在适宜温度下种子萌发率变化不明显;种子保存方式的不同造成种子萌发情况的差异，但差异不明显;黑暗条件下比近似黑暗条件下的种子萌发率略低。上述因素对种子萌发均具有一定影响，但总体特征是种子萌发对光照的反应表现为强光抑制种子的萌发，黑暗促进种子萌发。当温度较高时(15:25C)，光照与黑暗条件下种子萌发率差异不大，但黑暗条件下种子的萌发速率显著高于光照条件下;当其它条件相同时，种子萌发率和萌发速率显著高于温度较低时(10:20C)。因而，适宜的温度和黑暗条件有利于油蒿与籽蒿种子的萌发。在飞播实践时应为种子创造一定的沙埋条件，创造有利于种子萌发的黑暗环境，促进种子的萌发，提高飞播工作的成效。

雄性生殖道局部免疫

：雄性生殖道局部免疫在性传播疾病的防治、免疫不育的防治和免疫避孕方面都具有十分重要的作用。本文 结合作者的研究工作，介绍了雄性泌尿生殖道的结构特征、天然和获得性的抗感染因子、抗精子免疫反应、性激素 对雄性生殖道免疫力的调控作用以及雄性生殖道的获得性免疫应答的激活等方面的研究动态，提出了今后的研究 方向，认为除了深入研究获得性免疫之外，雄性生殖道内天然免疫力的研究，应是十分值得关注的新方向。 39600016) ,云南省应用基础基金(96C097Q ,97C092M) 等资助。

抚仙湖外来黄颡鱼种群的年龄和生长特征

黄颡鱼(Pelteobagrusfulvidraco)是近年被无意引入到抚仙湖的外来鱼类,自2002年以来在渔获物中已形成了较为稳定的产量。根据2002年9月至2005年5月采集的708尾标本对抚仙湖黄颡鱼种群的年龄和生长特征进行了研究。以脊椎骨作为年龄鉴定的材料,表明种群的年龄分别为雌性0+-5+龄6个龄组和雄性0+-7+龄8个龄组组成;拟合的VonBertalanffy生长参数为雄性L∞=294·68mm,k=0·2476/y,t0=-0·0298y,W∞=209·93g;雌性L∞=257·13mm,

Elongation Factor ELL (Eleven-Nineteen Lysine-rich Leukemia) Acts as a Transcription Factor for Direct Thrombospondin-1 Regulation

The eleven-nineteen lysine-rich leukemia (ELL) gene undergoes translocation and fuses in-frame to the multiple lineage leukemia gene in a substantial proportion of patients suffering from acute forms of leukemia. Studies show that ELL indirectly modulates transcription by serving as a regulator for transcriptional elongation as well as for p53, U19/Eaf2, and steroid receptor activities. Our in vitro and in vivo data demonstrate that ELL could also serve as a transcriptional factor to directly induce transcription of the thrombospondin-1 (TSP-1) gene. Experiments using ELL deletion mutants established that full-length ELL is required for the TSP-1 up-regulation and that the trans-activation domain likely resides in the carboxyl terminus. Moreover, the DNA binding domain may localize to the first 45 amino acids of ELL. Not surprisingly, multiple lineage leukemia-ELL, which lacks these amino acids, did not induce expression from the TSP-1 promoter. In addition, the ELL core-response element appears to localize in the -1426 to -1418 region of the TSP-1 promoter. Finally, studies using zebrafish confirmed that ELL regulates TSP-1 mRNA expression in vivo, and ELL could inhibit zebrafish vasculogenesis, at least in part, through up-regulating TSP-1. Given the importance of TSP-1 as an anti-angiogenic protein, our findings may have important ramifications for better understanding cancer.

The field emission properties of nonpolar a-plane n-type GaN films grown on nano-patterned sapphire substrates

Si-doped nonpolar a-plane GaN films were grown on nanopatterned sapphire substrates by a low-pressure metal organic chemical vapor deposition (MOCVD) system. The structure, morphology and field emission properties of the sample were studied by means of high-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), and field emission measurement. The XRD analysis shows that the sample is a nonpolar a-plane (11 (2) over bar0) GaN film. The field emission measurement shows that the nonpolar GaN films exhibit excellent field emission properties with a threshold emission field of as low as 10 V/mu m at a current density of 0.63 mu A/cm(2), and a high field emission current density of 74 mA/cm(2) at an applied field of 24 V/mu m. Moreover, the Fowler-Nordheirn plot of the sample fits a near linear relation. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

An algorithm of analysis tools on points distribution in high dimension space: The distance of a point and an infinite sub-space

This paper discusses the algorithm on the distance from a point and an infinite sub-space in high dimensional space With the development of Information Geometry([1]), the analysis tools of points distribution in high dimension space, as a measure of calculability, draw more attention of experts of pattern recognition. By the assistance of these tools, Geometrical properties of sets of samples in high-dimensional structures are studied, under guidance of the established properties and theorems in high-dimensional geometry.