3-三苯基锗基-1,1-二苯基-1-丁醇类化合物的拉曼光谱和红外光谱研究

我们合成３－三苯基锗基－１,１－二苯基－１－丙醇及同系物３－三苯基锗基－１,１－二苯基－１－丁醇;３－三苯基锗基－２－甲基－１,１－二苯基－１－丙醇,这些化合物都是有机锗类化合物,是具有抗肿瘤活性的化合物３－三苯基锗基－１－二苯基－１－丙醇的类似物,它们可能具有生物活性。我们测量了它们的拉曼光谱及红外光谱。经光谱分析,指认了主要波数所对应的分子振动。在这三种化合物中,Ｇｅ－Ｐｈ的伸缩振动出现在１０     

无机溶致液晶研究进展

目前发现的液晶多数为有机液晶,无机液晶非常少见。非球形无机胶体(棒状或盘状)体系在排斥体积熵的作用下可形成液晶相,即无机溶致液晶。由于其具有的理论意义和潜在的应用价值,无机液晶近年来引起了人们的关注。本文综述了无机溶致液晶的研究历史和最新进展。     

沙枣花油成份的研究

沙枣(Elaeagnus.angustifalia.L,胡颓子科胡颓子属)。是我国西北地区特有的野生耐旱植物。生长面积很大,是防风固沙的优良树种。每年4—5月开花,6—7月结果,果实即为沙枣。沙枣花能散发出持久的清香,这种独特的香味深为人们所喜爱。我们为了开辟一种新的天然香源,对沙枣花香气成份进行了研究。先后采用了吸附、     

Realization of Low Threshold of InGaAs／InA1As Quantum Cascade Laser

By optimizing the molecule beam epitaxy growth condition, the quality of quantum cascade (QC) material has greatly been improved. The spectrum of double x-ray diffraction indicates that the interface between the constituent layers is very smooth, the lattice mismatch between the epilayer and the substrate is less than 0.1%,and the periodicity fluctuation of the active region is not more than 4.2%. The QC laser with the emission wavelength of about 5.1μm is operated at the threshold of 0.73 kA/cm^2 at liquid nitrogen temperature with the repetition rate of lOkHz and at a duty cycle of 1%. Meanwhile, the performance of the laser can be improved with suitable post process techniques such as the metallic ohmic contact technology.     

同步加速器Barrier Bucket高频电压的研究

同步加速器Barrier Bucket高频系统用于克服空间电荷效应的影响,并对束团进行预压缩从而实现束团的多次累积来提高束流的流强。实现Barrier Bucket束流多次累积,要求在同步环高频加速腔上产生一个单正弦电压信号。针对单正弦波形的特点,讨论在同轴加载腔上产生该电压波形的方法和条件。通过对单正弦信号的频谱分析得出信号对加速腔高频系统的带宽要求,运用等效并联电路的方法并将同轴加载腔作线性时不变近似,求出输出的腔体电压与输入的激励电流间的关系。Barrier Bucket电压信号对加速腔整个高频系统的带宽要求至少应为单正弦频率的两倍。输入的激励电流为单正弦信号的基础上叠加上一个直流脉冲偏置,偏置大小为腔体Q值。最后,根据分析的结果在兰州重离子加速器冷却储存实验环（CSRe）高频系统的铁氧体加载腔和新研制的磁合金加载腔系统上进行测试,并对测试结果作相关讨论。     

基于插层化学的单晶氧化钨纳米片的制备、表征与形成机制

结合插层化学与湿化学方法的优点, 建立了一种高比表面积、大径厚比、易分散的二维氧化钨(WO3)纳米片单晶的制备新方法. 微米级WO3与Bi2O3在800 ℃通过固相反应生成层状化合物Bi2W2O9; 所得到的Bi2W2O9经盐酸选择性溶出[Bi2O2]层后得到质子化形式的H2W2O7·xH2O相. 以H2W2O7·xH2O为钨源, 以辛胺插层所得无机-有机混杂纳米带为前驱物, 经硝酸氧化除去前驱物中的有机组分后得到正交相WO3·H2O纳米片; 将所得到的WO3·H2O纳米片在250~ 450 ℃和空气气氛中热处理2~5 h(升温速率为2 ℃/min), 得到单斜相WO3单晶纳米片. TEM与SEM分析结果表明, 单晶WO3·H2O与WO3纳米片的形貌相似, 其大小为(200~500) nm×(200~500) nm, 厚度为10~30 nm; 所得WO3·H2O与WO3纳米片单晶的厚度方向分别为[010]和[001]. N2吸附结果表明, WO3·H2O与WO3纳米片的比表面积分别可达到250与180 m2/g.     

中空纤维液相微萃取-气相色谱/质谱联用检测水中的氯化苄

建立了一种以中空纤维液相微萃取(HF-LPME)前处理样品,利用气相色谱/质谱(GC/MS)对水中痕量氯化苄进行检测的方法。优化的实验条件为:3.0μL甲苯为萃取溶剂,在中等搅拌速率下室温萃取15 min。方法的线性范围为1~100μg/L,线性相关系数r=0.9995;检出限为0.5μg/L(S/N=3);相对标准偏差为5.37%(n=5)。用于水库水和被污染河水的测定,加标回收率分别为95.7%和93.6%,结果满意。     

中空纤维液相微萃取技术及其应用进展

中空纤维液相微萃取(HF-LPME)是一种新近发展起来的样品预处理技术.具有使用溶剂少,可集采样、萃取、浓缩于一体等优点,是一种环境友好的样品预处理技术.综述了中空纤维液相微萃取的操作模式、影响因素及其应用进展.     

Interference Phase of Neutrino Oscillation in Schwarzschild-de Sitter Space-Time

We study the mass neutrino interference phase in Schwarzschild-de Sitter space time along the null trajectory and the geodesic line and obtain the effects of cosmological constant A on the neutrino oscillation. Firstly, in the high energy limit, we find that the phase along the geodesic keeps the double of that along the null. Secondly, we calculate the phase on the condition that the cosmological constant, A, is a small quantity. The correction of the phase due to A is given. Finally, we calculate the proper oscillation length in Schwarzschild-de Sitter space-time, which increases because of the existence of A, compared with the result in Schwarzschild space-time. All of our results can be reduced to those in Schwarzschild space-time as A approaches to zero.     

Modified GIT model for predicting wind-speed behavior of low-grazing-angle radar sea clutter

A modified GIT model for describing the variational trend of mean clutter reflectivity as a function of wind speed is proposed. It uses two slope adjustment factors and two critical wind-speed factors to define and adjust the increasing slope of reflectivity with respect to wind speed. In addition, it uses a constant factor to compensate the overall amplitude of clutter reflectivity. The performance of the modified GIT model has been verified on the basis of the L-band low-grazing-angle radar sea clutter data. The results are in good agreement with the experimental data, indicating that the model is more effective in predicting the wind-speed behavior of clutter reflectivity than the conventional GIT model, especially for lower and higher wind speeds. We believe that the proposed model can provide deeper insights into the relationship between radar sea clutter reflectivity and sea state conditions.