Bioisosterism between Sulfonyl Group and Phosphoryl Group-The Synthesis of New ALS Inhibitors N-(Arylamino Hydroxyl Phosphoryl)-N'-(4,6-Dimethoxypyrimidine-2-yl)ureas

Sulfonylureaherbicidesisanewclassofherbicidesdiscoveredinthemid-l97O's',whosemodeofactionhasbeenestablishedastheinhibitionofacetolactatesynthase(ALS,alsoreferredasacetohydroxyacidsynthase)'-Muchattentionhasbeenfocussedonthiskindofcompound,sincetheyhaveunprecedenteduserates,ahighdegreeofselectivity,andexcellentenvironmentalsafety'.NumerousmodificationsofthestrUctureofthisclassofherbicideshavebeenreported'.Wehavetakenattentiontothesimi1alltybetweenthesulfonylgroup(-SO2-)andphosphoryIgroup[-P…     

单个波长到多个波长的变换实验

报道一种波长变换的新方法.采用此方法不需要任何泵浦光便能够直接将信号光变换成在特定谱宽内的任意多个任意波长的变换光,这对于将来的波分复用光网络提供了较大的方便.此波长变换的原理是利用色散位移光纤的非线性效应产生超连续光谱(SC)信号,由于这种SC信号携带有变换光信号,对这种连续谱进行滤波便能够得到所需要的任意频率的变换信号.此变换方式具有变换频带宽,偏振不敏感的优点。     

Atomic coherence effects in the ion-trap laser

The influence of atomic coherence effects on the statistical and spectral properties of the ion-trap laser is investigated. Various pump configurations are considered for a realistic level scheme using a Ca ion. Compared to previous suggestions, 50% more output is obtained.     

线圈型全光纤偏振器的研究

本文采用等效电流法对线圈型全光纤偏振器进行了分析计算.对应于保偏光纤中两正交传输基模的消光比,提出了一种分析保偏光纤弯曲损耗的新方法,这种方法基于将保偏光纤两个不同偏振模式分别等效为两个普通圆光纤的基模,等效参数通过测量不同偏振模式的模场半径来确定.实验证明这种理论计算方法与实验结果一致.最终,我们研制出的线圈型光纤偏振器在1.31μm工作波长下,实测消光比达30dB以上,工作偏振模式插入损耗≤3dB.     

突体剖面线型的流噪声机理分析和试验研究

本文在分析突体马蹄涡和湍流脉动压力特性的基础上，在中国船舶科学研究中心０３Ｂ水筒，试验比较了不同剖面线型的突体模型流动噪声，降噪效果３－５ｄＢ，提出了突体部面低噪声设计的实验依据和具体方法。     

纳米晶Y_2SiO_5∶Eu的浓度猝灭研究

报道了分别用溶胶－凝胶法合成的Ｙ２ＳｉＯ５∶Ｅｕ纳米晶和用高温固相法合成常规尺度的Ｙ２ＳｉＯ５∶Ｅｕ材料的光致发光光谱和猝灭浓度的实验研究．结果表明：纳米Ｙ２－ｘＥｕｘＳｉＯ５比常规尺度的Ｙ２－ｘＥｕｘＳｉＯ５有更高的猝灭浓度和更高的发光亮度．理论分析认为这是由于在纳米材料中能量共振传递被阻断和猝灭中心在各个纳米晶内分布的涨落造成的．这个结果为高亮度的Ｙ２ＳｉＯ５∶Ｅｕ纳米材料的实际开发应用展示了广阔前景．     

The practice for eight-year operation of the cobalt-60 irradiation facility at Beijing Radiation Application Research Center

The radiation facility was made by Sulzer Company in Switzerland. The designed capacity is 3.7 × 10¹⁶Bq( 1MCi) and 12.21 × 10¹⁵Bq(330kCi)of Cobalt -60 source was loaded at the first phase. Current cobalt -60 source-loading is 2.4 × 10¹⁶Bq(650kCi). The equipment assembling and installation regulating and testing were completed at the end of 1988. The facility was put into commissioning in 1989. It operates 7000–8000 hours per year. The facility has been utilized to carry out many research work and irradiate many kinds of items. Lots of economical benefits have been gained since then. Now it is becoming a radiation processing model base in China. This paper summarized the strong and weak points of the design of the facility through in eight years' practice and analysed the economical benefits.     

Dimeric stilbenes of the wood of Maackia amurensis

Dimeric stilbenes have been isolated from the wood of Amur maackia for the first time. Two of them have been identified as the known scirpusins A and B. The structure of a new dimeric stilbene with a dioxane linkage, which has been called maackinin, has been established. The PMR and¹³C NMR spectra of the substances isolated have been studied in detail.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 468–476, September–October, 1992.     

Monitoring of ionic concentrations in airborne particles and rain water in an urban area of central Germany

The primary objective of this investigation was to document fluctuations of levels of ions in airborne particles and in rain water with the help of ion chromatography. The environmental emission situation in the investigated geographic area is characterized by a widespread use of domestic coal-burning furnaces. The use of a parallel impactor for particulate sampling permits the results to be interpreted additionally in terms of particle size. The anions and cations were extracted from the filters in the sampling devices into ethanol-water mixtures by sonication. Rain water samples were analysed after a simple dilution step. The data obtained on ionic fluctuations are compared with similar data sets published by other laboratories.     

美国热煤气脱硫吸附剂的发展现状

概述了美国几种较成熟的热煤气脱硫吸附剂的配方、制备技术及吸附剂在若干试验条件下强度、活性、寿命等宏观特性的测试结果。