减毒麻疹活疫苗对小鼠的细胞遗传学效应

麻疹疫苗可引起小鼠骨髓微核细胞率、染色体畸变率以及精细胞微核细胞率 明显升高, 与接种剂量和接种后的时间有关; 生殖细胞染色体畸变和对照比无 显著性差异。图版2表3参21

长薄鳅年龄与生长的研究

在长江上游收集长薄鳅标本,对其年龄与生长进行了研究。以鳞片、耳石、脊椎骨和胸鳍鳍条为年龄鉴定材料。透射光下,鳞片的环沟和辐射沟呈现透明的凹沟。长薄鳅的鳞径与体长呈显著的正相关,回归方程为L=0.4326+82.5738R(n=37,r=0.9899);体长与体重的关系方程为W=4.736×10-3L3.3045(n=37,R2=0.9971);生长方程为L=-1.3189+5.2132t(r=0.9892)。

Amplified fragment length polymorphism analysis to identify the genetic structure of the Gymnocypris przewalskii (Kessler, 1876) population from the Qinghai Basin, China

Amplified fragment length polymorphism (AFLP) was used to analyse the genetic structure of 45 individuals of Gymnocypris przewalskii (Kessler, 1876), an endangered and state-protected rare fish species, from three areas [the Heima (HM), Buha (BH) and Shaliu rivers (SL), all draining into Qinghai Lake]. A total of 563 polymorphic loci were detected. The HM, BH and SL populations have 435, 433 and 391 loci, respectively (Zhu and Wu, 1975), which account for 77.26%, 76.91% and 69.45% of the total number of polymorphic loci of each population, respectively. The Nei indices of genetic diversities (H) of the three populations were calculated to be 0.2869 (HM), 0.2884 (BH) and 0.2663 (SL), respectively. Their Shannon informative indices are 0.4244, 0.4251 and 0.3915, respectively. Research results show that the mean genetic distance between HM and BH is the smallest (0.0511), between BH and SL is the second shortest (0.0608), and between HM and SL is the largest (0.0713), with the mean genetic distance among the three populations being over 0.05. Data mentioned above indicate that the three populations have a certain genetic differentiation. The total genetic diversity (H-t = 0.3045) and the mean value of genetic diversity within the population (H-s = 0.2786) indicate that the variations have mainly come from within the population.

高电子迁移率晶体管及其制作方法

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Growth and fabrication of high performance 980nm strained InGaAs quantum well lasers using novel hybrid material system of InGaAsP and AlGaAs

In this paper, we report on the design, growth and fabrication of 980nm strained InGaAs quantum well lasers employing novel material system of Al-free active region and AlGaAs cladding layers. The use of AlGaAs cladding instead of InGaP provides potential advantages in laser structure design, improvement of surface morphology and laser performance. We demonstrate an optimized broad-waveguide structure for obtaining high power 980nm quantum well lasers with low vertical beam divergence. The laser structure was grown by low-pressure metalorganic chemical vapor deposition, which exhibit a high internal quantum efficiency of similar to 90% and a low internal loss of 1.5-2.5 cm(-1). The broad-area and ridge-waveguide laser devices are both fabricated. For 100 mu m wide stripe lasers with cavity length of 800 mu m, a low threshold current of 170mA, a high slope efficiency of 1.0W/A and high output power of more than 3.5W are achieved. The temperature dependences of the threshold current and the emitting spectra demonstrate a very high characteristic temperature coefficient (T-o) of 200-250K and a wavelength shift coefficient of 0.34nm/degrees C. For 4 mu m-width ridge waveguide structure laser devices, a maximum output power of 340mW with GOD-free thermal roll-over characteristics is obtained.

沈阳市科普公园总体规划及生态园林设计

随着全球工业化进程的加速以及科学技术日新月异的发展，人类在渴求获得更多知识的同时，更希望能够生活和工作在一个舒适的环境中。沈阳市科普公园总体规划正是本着以普及多学科的科学知识为主题，同时在总体规划中坚持以植物造园为主，贯彻城市绿化规划中的生态园林思想。本文通过对国内外科普主题公园发展历史及现状的分析研究，论述了建立沈阳市科普公园的现实意义；通过对科普公园规划与其它城市绿化规划和园林规划与景观规划关系的分析，提出了科普公园规划的原则；通过对国内外科普主题公园选址情况的分析研究，并结合沈阳市科普公园规划区自然及人文情况的调查，进行了沈阳市科普公园选址的适宜度分析；针对沈阳市科普公园规划建设的具体实际，在提出沈阳市科普公园规划原则和规划构思的基础上，确定了沈阳市科普公园总体规划布局。沈阳市科普公园既是沈阳科普教育基地，同时又是沈阳市园林规划的一个重要组成部分，通过对生态园林概念的提出，生态园林生态系统的生态效益、环境效益和社会效益的综合分析，提出了沈阳市科普公园建设必须坚持走生态园林的道路。结合国内外科普主题公园生态园林的设计方法和沈阳市科普公园生态园林规划构思，确定了沈阳市科普公园生态园林规划的植物配置原则，并就和功能区的具体实际，完成了沈阳市科普公园各功能区包括科学宫、海洋世界、中心科技广场、生态园（含生物循环园、乡土植物生态园、稀有濒危植物园和科普树木园）等园区的生态园林规划。最后，通过对城市园林发展历史的简要回顾，提出了生态园林是城市园林规划的主流和方向，生态园林构思在科普公园规划中有着广阔的发展前景。

微结构疏水表面对界面流动的影响

<正>通过MicroPIV/PTV系统测量带有微结构的PDMS微流道(22μm×6μm,长8mm)内的速度分布。流道侧壁的PDMS微结构是通过软光刻微加工工艺制成,其特征宽度在1～10μm范围。为了研究微结构尺寸的影响,我们测量了3种不同尺度微结构对速度分布的影响。示踪粒子为200nm聚苯乙烯荧光粒子。实验管道Re约0.01。

~(189)W衰变纲图

用14.8 MeV中子同天然锇反应, 取道192O(n, α) 反应产生189W。通过放射化学分离流程, 从反应产物中分出W。用高纯Ge探测器完成放射性W样品γ射线单谱的测量。在189Re激发能级文献值的基础上并依据衰变和能级的关系以及189W衰变的γ射线能量和相对强度的实验数据, 给出了建议的189W衰变纲图。

The synthesis and catalytic activity of poly(bis(imino)pyridyl) iron(II) metallodendrimer

The first and second generation carbosilane dendrimers with silicon hydride terminated were synthesized, and then reacted with bis(imino)pyridyl containing allyl [4-CH2==CHCH2-2,6-(Pr2C6H3N)-Pr-i==CMe(C5H3N)MeC==N(2,6-'Pr2C6H3)], in the presence of H2PtCl6 as a hydrosilylation catalyst, to afford the first and second generation carbosilane supported ligands. Complexation reactions with FeCl(2)(.)4H(2)O give rise to iron-containing carbosilane dendrimers with FeCl2 moieties bound on the periphery. The metallodendrimers were used as catalyst precursors, activated with modified methylaluminoxane, for the polymerization of ethylene. In the case of low Al/Fe molar ratio, the metallodendrimers display much higher catalytic activity towards ethylene polymerization and produce much higher molecule weight polyethylenes than the corresponding single-nuclear complex under the same conditions.

合成均四甲苯的方法

一种合成均四甲苯的方法，其步骤为原料汽化混合、催化烷基化反应、气液分离、常压蒸馏、冷却结晶、离心分离；反应器为径向反应器，采用改性的氢型ＺＳＭ－５分子筛催化剂，使其转化率高达２５－３５％，产品油中目的产品均四甲苯的含量高达６０－８０％，催化剂再生周期增长１－３倍，使用寿命增加１－２倍。