烷类衍生物氟里昂系列替代物的研究

广泛应用于制冷工程等各领域的氟里昂制冷剂因破坏大气臭氧层和温室效应而将被逐步限用和淘汰。文章利用建立的工质选择理论和划分的结构特性图，通过数学模型和几何模型对烷类衍生物氟里昂系列的结构特性进行研究分析，取得了一系列有价值的结论，为CFC禁用和替代问题的研究指出了更广阔的领域。

AlGaInAs-InPMicrocylinder Lasers Connected With an Output Waveguide

AlGaInAs-InPmicrocylinder lasers connected with an output waveguide are fabricated by planar technology. Room-temperature continuous-wave operation with a threshold current of 8 mA is realized for a microcylinder laser with the radius of 10 mu m and the output waveguide width of 2 mu m. The mode Q-factor of 1.2 x 10(4) is measured from the laser spectrum at the threshold. Coupled mode characteristics are analyzed by 2-D finite-difference time-domain simulation and the analytical solution of whispering-gallery modes. The calculated mode Q-factors of coupled modes are in the same order as the measured value.

Lanxide技术合成含烧结助剂的复合AIN粉体

高纯度的氮气中，以Al-Mg-Y合金为母合金，利用Lanxide技术合成了含烧结助剂 Y_2O_3的复合AIN粉体．通过扫描电镜、X射线衍射、粒径分析及化学成分分析等检测手段对氮化产物进行表征．实验结果表明，合金氮化反应完全，氮化产物疏松易于粉化．粉化后获得的复合AIN粉体具有纯度高，氧杂质含量低，粒度细小等优点。

Linear and nonlinear optical properties of the PbSe quantum dots doped germane-silica glass optical fiber

We report development of a new fiber doped with PbSe quantum dots for nonlinear optical applications. PbSe quantum dots related absorption peaks were obtained at 1021, 1093 and 1351 nm. The resonant optical nonlinearity and attenuation at 1500 nm were measured to be 9.4 × 10−16 m2/W and 0.01 dB/m, respectively. The emission around 1540 nm was observed upon near resonant pumping at 1064 nm.

防护林阶段定向经营研究Ⅰ.理论基础

基于多年防护林经营研究与实践 ,在分析防护林经营目的的基础上 ,提出了防护林阶段定向经营理论基础 .以防护林的防护成熟为核心 ,将防护林经营阶段划分为成熟前期 ,即从栽植后形成相对稳定的幼林到初始防护成熟龄 ;防护成熟期 ,防护成熟状态持续的时期 ,即从初始防护成熟龄到终止防护成熟龄 ;更新期 ,林木接近自然成熟开始更新直到更新结束并形成相对稳定的幼林 .防护林经营的定向是指在任何经营阶段内 ,一切经营技术与措施都是为了使防护林向着成熟的状态发展 ,即防护成熟是防护林经营的方向 ,是最终目的 .为尽量维持防护林的成熟状态并使防护效益不间断 ,针对发育正常与低质衰退的林分 ,在各个经营阶段内采取相应的系列经营管理与改造措施 .

半湿润农田杂草及施氮对夏玉米产量及氮素利用的影响

以土垫旱耕人为土为供试土壤,采用大田试验,研究了半湿润农田两种杂草处理方式下(成熟后期清除杂草-A区和苗期开始清除杂草-B区),不同施氮量对夏玉米产量及氮素利用效率的影响。结果表明,当施氮量为0、45、90、1351、80 kg/hm2时,B区玉米子粒产量比A区分别增加了8.7%、12.1%、9.4%、5.0%和12.5%;吸氮量分别增加了1.5、2.9、4.85、.2和4.3 kg/hm2。A区和B区全生育期0—100 cm土层矿质氮(Nmin)累积量变化趋势基本一致,但B区比A区变幅较大。当施氮量为45、90、135和180 kg/hm2时,B区氮肥利用率、氮肥农学利用率、氮肥生理利用率均高于A区。研究还发现,在A区,当施氮量为180 kg/hm2时,杂草干生物量最大,为1518.3 kg/hm2,不施氮时,杂草的生物量最低,为845.7 kg/hm2;杂草的吸氮量随施氮量的增加而增加。可见,清除玉米农田杂草不仅可以提高作物产量和氮肥利用率,而且在减少氮素损失方面具有一定作用。

岷江上游人口特征

通过提取岷江上游5县1986~2003年统计年鉴的人口和经济数据,以研究区行政区划图(1∶250 000)为地理信息基础数据,在ArcGIS平台上,建立人口空间数据库,采用传统人口统计和GIS空间分析相结合的方法,对岷江上游5县的人口空间分布特征与变化以及影响其变化的因素进行了研究。结果表明,研究区是以藏族、羌族、回族等少数民族为主的聚居区,其人口总量规模小、人口增长缓慢、人口密度偏小;人口的空间结构状况趋于不均衡化,人口再分布活力明显下降;人口重心从1950~2003年由北到南移动了6.30 km,反映出研究区经济发展良好的区域在南部(即汶川县)方向;影响人口分布的主要因素有河流、道路、海拔、土地的利用方式和经济吸引力等。

非晶态TiO_2-SiO_2的网络缺陷与紫外吸收机制的研究

分析了非桥氧,E＇心等网络缺陷的能级结构,探讨了含TiO_2熔石英紫外吸收边界向长波移动的物理机制。

Molecular phylogeny of some genera of Pamphagidae (Acridoidea, Orthoptera) from China based on mitochondrial 16S rDNA sequences

Based on the mitochondrial 16S ribosomal DNA partial sequences (473 bp) of 9 species of Pamphagidae (Acridoidea, Orthoptera) from China and of 4 species of Pamphagidae and 2 species of Pyrgomorphidae and Acrididae (as outgroups) retrieved from GenBank, we constructed the molecular phylogeny using the Neighbor Joining (NJ) and Minimum Evolution ( ME) methods based on the nucleotide Kimura 2-parameter model. The results of our study shown that: 1) the ranges of the 16S rDNA nucleotide divergence between two species of a genus were 0.21%, among genera of a subfamily were 0.42-3.38%, and among subfamilies of Pamphagidae were 1.90-8.88%, respectively. The phylogenetic tree shows that: 1) all Pamphagidae taxa form a monophyletic clade, and are well separated from the outgroup; 2) the African taxa Porthetinae (Lobosceliana brevicornis) and Akicerinae (Batrachotetrix sp.) are distinctly separated from the Chinese taxa Prionotropisinae; 3) Haplotropis bruneriana and Glauia terrea of Pamphaginae are nested in the middle of the tree, but their phylogenetic status is uncertain in this study; 4) 8 genera of Asiotmethis, Beybienkia, Mongolotmethis, Sinotmethis, Rhinotmethis, Filchnerella, Eotmethis and Pseudotmethis from China are all grouped into the subfamily Prionotropisinae, but their phylogenetic relationships are not clearly resolved.

PXJ-Ⅱ排险机器人

介绍了一种可在危险环境下作业的遥控机器人──PXJ－Ⅱ排险机器人，分析了其功能指标及结构，简述了以武器系统和传感器为主的机器人辅助系统及其实用意义。