High-Power Continuous-Wave Diode-End-Pumped Intracavity Frequency Doubled Nd：YVO4 Laser at 671 nm with a Compact Three-Element Cavity

We report a high-power high-efficient continuous-wave （cw） diode-end-pumped Nd：YVO4 1342-nm laser with a short plane-parallel cavity and an efficient cw intracavity frequency-doubled red laser at 671 nm with a compact three-element cavity. At incident pump power of 20.6 W, a maximum output power of 7 W at 1342 nm is obtained with a slope effciency of 37.3%. By inserting a type-Ⅰ critical phase-matched LBO crystal as intracavity frequencydoubler, a cw red output as much as 2.85-W is achieved with an incident pump power of 16.9 W, inducing an optical-to-optical conversion efficiency of 16.9%. To the best of our knowledge, this is the highest output of diodepumped solid-state Nd：YVO4 red laser. During half an hour, the red output is very stable, and the instability of output power is less than 1%.     

电感耦合等离子体质谱法测定土壤中可溶态稀土元素

采用电感耦合等离子体质谱法(简称ICP-MS)测定土壤中可溶态稀土元素.可溶态稀土中由于引入NaAc,使得主要基体元素Na、Mg、Ca对稀土元素的信号强度均表现出抑制效应.我们引入In内标元素可有效地抑制分析信号的动态飘移,比较了分离基体与直接测定两种方法,结果表明,两种方法可得到一致的结果.稀土元素的检出限为0.001～0.011 ng/mL.标准加入回收率为93.2%～111.5%.不经分离可直接测定土壤中可溶态稀土元素.     

Theoretical Analysis of Structures of Ga4N4 Clusters

The structures and energies of a Ga4N4 cluster have been calculated using a full-potential linear-muffin-tin-orbital molecular-dynamics (FP-LMTO MD) method. We obtained twenty-four structures for a Ga4N4 cluster. The most stable structure we obtained is a C8 three-dimensional structure, the energy of which is lower than that of the C2v symmetry structure proposed by Kandalam et al. [J. Phys. Chem. B106 (2002) 1945] The calculated results show that the isomer with an N3 subunit is preferred, supporting the previous result made by Kandalam et al,We found that the most stable structure of Ga4N4 clusters presented semiconductor-like properties through the calculation of the density of states.     

ICP—AES法同时测定麦饭石中的多种元素

本文阐述了用ＨＣｌ，、ＨＣｌＯ４及ＨＦ在高压溶样哭喊 内消化麦饭石，应用ＩＣＰ－ＡＥＳ法同时测定麦饭石中的１４种元素。本法的准确度及精密度均达到满意结果。方法简便，快速。     

ICP—AES法测定玩具材料和涂料中的可溶性有害元素

本文报道用ＩＣＰ－ＡＥＳ法对玩具材料和涂料被吞咽在消化系统内停留４小时的模拟条件下溶出的Ｓｂ，Ａｓ，Ｂａ，Ｃｄ，Ｃｒ，Ｐｂ，Ｈｇ和Ｓｅ八种有害元素的量进行测定，以确保儿童玩具的安全性和促进玩具商品的顺利出口。     

表面单层组装多环芳烃荧光行为的Monte Carlo模拟

用MonteCarlo方法模拟了惰性基片表面单层组装多环芳烃 (传感元素 )的荧光行为 ,考察了基片表面传感元素固定化百分率、传感元素激发百分率 (光吸收效率 )以及传感元素分子在介质中相互缔合形成激基缔合物趋势大小 (用P表示 ,P值介于 0到 1)等因素对传感元素激基缔合物荧光发射强度与单体荧光发射强度之比所产生的影响 .结果表明 ,具有中等光吸收效率的多环芳烃适宜于作为传感元素 ,中等固定化密度的基片可能具有比较理想的传感性能     

稀土—氮复合孕育剂对灰铸铁石墨组织的影响

采用主碳当量灰铸铁作为试验材料，以孕育处理的方式加入稀土和氮，研究了稀土，氮及二者复合能对石墨数量和石墨表面形貌的影响。试验结果表明，稀土和氮，特别是它们复合加入，使石墨百分含量减少；氮和氮与稀土复合孕育使灰铸铁的石墨表面变粗糙，且端部有钝化现象。     

苯酚在Ln—ZrO2催化剂上直接氧化制取邻苯二酚地研究

以Ｌｎ－ＺｒＯ２作为苯酚选择氧化催化剂，用过氧化氢氧化，得到邻苯二酚选择性高达８５．７％的良好结果，添加稀土元素镧，钕的氧化锆催化剂的单纯的二氧化钛催化剂相比，邻苯二酚选择性分别提高了７３．５％和６７．８％。     

关于群图的{Cni∈I}—因子

设Cn是长度为n(n≥3)的圈，如果图G的生成子图F的每个分支都同构于圈集{Cni∈I}的一个元素，列F称为G的一外{Cni∈I}—因子，若G是其边不重{Cni∈I}—因子之并，则G称为可—{Cni∈I}因子化，1988年，M．-J．P．Ruiz在[1]中给出了有限简单连通无向群图，有Cn—因子的充分条件及可{Ca,…Cp}—因子他的充分条件，然而，Ruiz的结果是本相应结果的特例。