理科(18)题别解

试题如图3,在直三棱柱ABC-A1B1C1中,底面是等腰直角三角形,∠ACB=90°,侧棱AA1=2,D、E分别是CC1与A1B的中点,点E在平面ABD上的射影是△ABD的重心G.     

理科(20)题文科(21)题别解

试题在某海滨城市附近海面有一台风,据监测,当前台风中心位于城市O的东偏南θ(θ=arc cos(2)/(10))方向300km的海面P处,并以20km/h的速度向西偏北45°方向移动,台风侵袭的范围为圆形区域,当前半径为60km,并以10km/h的速度不断增大,问几小时后该城市开始受到台风的侵袭?     

非线性方程组的符号矩阵，正则分裂与单调包含（Ⅰ）

As a continuation of part I of the paper under the same title, we developgeneral monotonic enclosure methods for the couple systems of the splitting equations {x=G([x]a,[x]b,[y]c) y=G([y]a,[y]b,[x]c),which models the system of equations associated with hybrid and aaynchronotts monotonicity as well as convexity. The resulting algorithms and convergence theorems generalize and unify various known methods and monotonic enclosure theorents established by other authors.     

溶剂浸渍树脂孔结构的研究

用萃取剂N_(235)浸渍大孔苯乙烯—二乙烯苯(MSD)树脂制得了溶剂浸渍树脂。用压汞仪测定了溶剂浸渍树脂的孔体积、孔表面积和孔径等,用扫描电镜观察了溶剂浸渍树脂的形貌。MSD树脂对N_(235)吸附率随该树脂的交联度和混合致孔剂用量增加而增加。由于N_(235)分布于MSD树脂孔表面,浸渍树脂的孔体积、孔表面和孔径比MSD树脂显著下降。在孔径1～100nm孔表面吸附N_(235)量最大。低交联度MSD树脂对N_(235)吸附量低,且分布不均匀。     

NUCLEAR PORE COMPLEX IN SPERMATOGENESIS OF BEIJING DOMESTIC DUCK——ELECTRON MICROSCOPE OBSERVATION OF FREEZE-ETCHING

The nuclear pore complex in spermatogenesis of Beijing domestic duck has been studiedby means of electron microscopic observation of freeze-etching. The structure of the poreobserved proves to be in accord with the model of the nuclear pore complex proposed respec-tively by Franke (1970) and Roberts et al. (1970). But its central granule may be present(1--3 granules) or absent. The granules are considered to be material in transit. The sizeand frequency of the pore vary with different types of reproductive cells, which is believedto be related to the cells' function. The pores concentrate on the side of nucleus near Golgizone in primary spermatocyte and near the proacrosome of spermatid, and this shows thefunctional variety of parts in the nucleus.     

亚硒酸钠对人胃腺癌细胞中c—Ha—ras和c—erbB2癌基因及其蛋 …

应用细胞原位杂交和免疫胶体金技术，观察亚硒酸钠处理人胃腺癌细胞前后，ｃ－Ｈａ－ｒａｓ和ｃ－ｅｒｂＢ２癌基因转录水平及其产物Ｐ２１和Ｐ１８５癌蛋白表达的变化。结果表明，两种癌基因在ＭＧｃ８０－３细胞中活跃表达，亚硒酸钠能抑制ｃ－Ｈａ－ｒａｓ和ｃ－ｅｒｂＢ２癌基因的转录水平及Ｐ２１和Ｐ１８５癌蛋白的表达，这对于诱导胃癌细胞向下沉细胞方向逆具有重要意义。     

一种对等网络的通信分析与实时应用

讨论了Ｎｏｖｅｌｌ Ｄｏｓ７点对点对等网络的特点，对网络中点通信速率进行了估算，结果表明Ｎｏｖｅｌｌ Ｄｏｓ７特别适合中，小型实时局域网系统。介绍了该对等网络的一个实时应用－－县级中、小型电网调度自动化系统，该系统的设计和开发兼顾了低成本和满足用户基本需求这两个基本因素，使系统具有良好的性能价格比，具有工作可靠，配置灵活，使用方便等特点。     

平面曲柄摇杆机构最佳传力性能的设计

本文分析了平面曲柄摇杆机构工作行程的最佳传力条件，给出了优化工作行程最小传动角γＷｍｉｎ的设计公式和图线。为曲柄摇杆机构传力性能的最佳设计提供了依据。