N-(2-吡咯甲基)-1-苯基乙亚胺·二甲基铝的合成、结构及其催化丙交酯的活性

通过席夫碱配体N-（2-吡咯甲基）-1-苯基乙亚胺与三乙基铝按物质的量之比为1：1在无氧无水的条件下反应,合成了席夫碱铝的有机金属化合物N-（2-吡咯甲基）-1-苯基乙亚胺·二甲基铝。其结构分别用核磁氢谱、碳谱,元素分析和X射线单晶衍射技术进行了表征。铝化合物在催化外消旋丙交酯开环聚合反应中表现出了中等的活性并得到了以等规聚合为主的高聚物。     

基于混合固定相色谱柱的SPE-HPLC法检测环境水体中三嗪类除草剂

利用混合固定相色谱柱(Optimix SCX/C8)分析了8种三嗪类化合物,在0.01 mol/L乙酸钠缓冲溶液(pH4.2)-CH3CN(75：25,V/V)等度洗脱的流动相条件下,实现了利用液相色谱方法分离同分异构体敌草净和西草净,并对比了相同色谱条件下8种目标物在C8色谱柱上的分离效果;比较了PEP和C18固相萃...     

Rashba效应和Zeeman效应对各向异性量子点中束缚磁极化子性质的影响

采用Pekar变分法和幺正变换相结合的方法研究了各向异性量子点中束缚磁极化子的Rashba效应和Zeeman效应.通过理论推导,得到束缚磁极化子基态能量的表达式.讨论了极化子基态能量与横向有效受限长度、纵向有效受限长度、磁场回旋共振频率、库仑束缚势的关系.由于晶体结构反演非对称性和时间反演非对称性,极化子能量发生Rashba自旋轨道分裂和Zeeman分裂.在强、弱磁场下,分别讨论了Zeeman效应和Rashba效应在能量分裂中所占的主导地位.由于声子和杂质的存在,极化子比裸电子态更稳定.     

基于喹啉基的噁二唑酮类荧光探针合成及对Fe^(3+)的识别EI北大核心CSCD

以8-氨基喹啉为原料通过重氮化、还原、酰化等反应制备了3种新的喹啉基酰肼化合物1~3,并以其为原料与三光气发生环合反应进一步制备了3种噁二唑酮类化合物4~6。6种新的化合物结构均采用红外光谱、核磁共振谱和质谱等技术以及理论计算进行了深入分析。同时通过热重和荧光光谱等手段对化合物的热学和光学性质进行了测试和分析。结果表明,合成的6种化合物都具有良好的热稳定性,且具有较强的固体荧光发射性能。其中,化合物4~6可作为荧光探针对Fe离子具有高选择性和灵敏性的检测能力,其检出限分别为8.70×10^(-6),1.64×10^(-6),1.01×10^(-6)mol/L。此外,通过理论计算对6种化合物的发光原理也进行了深入分析。     

Hydrogen Sensors Based on AlGaN/AlN/GaN Schottky Diodes

Pt/AlGaN/AlN/GaN Schottky diodes are fabricated and characterized for hydrogen sensing. The Pt Schottky contact and the Ti/Al/Ni/Au ohmic contact are formed by evaporation. Both the forward and reverse currents of the device increase greatly when exposed to hydrogen gas. A shift of 0.3 V at 300 K is obtained at a fixed forward current after switching from N2 to 10%H2＋N2. The sensor responses under different concentrations from 50ppm H2 to 10%H2＋N2 at 373K are investigated. Time dependences of the device forward current at 0.5 V forward bias in N2 and air atmosphere at 300 and 373K are compared. Oxygen in air azcelerates the desorption of the hydrogen and the recovery of the sensor. Finally, the decrease of the Schottky barrier height and sensitivity Of the sensor are calculated.     

Effects of Annealing on Microstructure and Optical Properties of TiO2 Sculptured Thin Films

The evolution of microstructure and optical properties of TiO2 sculptured thin films under thermal annealing is reported. XRD, field emission SEM, UV-Vis-NIR spectra are employed to characterize the microstructural and optical properties. It is found that the optimum annealing temperature for linear birefringence is 500℃. The maximum of transmission difference for linear birefringence is up to 18%, which is more than twice of that in as-deposited thin films. In addition, the sample annealed at 500℃ has a minimum of column angle about 12℃. The competitive process between the microstructural and optical properties is discussed in detail. Post-annealing is a useful method to improve the linear birefringence in sculptured thin films for practical applications.     

迈克尔逊干涉仪上演示杨氏干涉

杨氏于1801年用单强光照射开有小孔S的光阑,在小孔S后面再放置一个开有两个小孔S1和S2的光阑,就完成了具有重大历史意义的杨氏干涉实验．后来,小孔S和S1及S2逐渐在杨氏实验装置中,如图1,S1和S2是两个相干点光源,必须足够小．否则,     

TBP-Pd（Ⅱ）-HCl萃取体系微乳的生成及溶液聚集态的谱学研究

采用动态激光光散射(DLS)、Fourier变换红外光谱(FTIR)、核磁共振波谱(31P-/1H NMR)等谱学技术,研究了TBP-Pd(Ⅱ)-HCl萃取有机相中微乳的形成以及溶液聚集态结构的变化。结果表明:(1)伴随钯的萃取,TBP萃取有机相中形成微乳。(2)萃取有机相中酸含量的变化导致溶液结构发生相应改变:胶团聚集体平均流体力学半径随有机相中酸含量的增加先增大而后又减小。微乳"内核水"的O—H伸缩振动吸收谱带逐渐宽化,与邻近的C—H伸缩振动区形成交迭,且有机相含酸量越高,交迭程度越大。水分子O—H—O弯曲变角振动吸收峰形也发生很大变化。TBP的PO伸缩振动明显向低频移动。核磁共振31P化学位移与活泼氢1H化学位移变化行为相反,说明TBP分子与酸和水分子发生缔合,形成RP=O.H 或RP=O.H3O ,并与PdCl42-存在相互作用。(3)有机相形成微乳水团后,由于大量H 的进入,微乳水团中酸浓度表现出明显的"增浓效应"。微乳水池内部微观环境的改变是导致钯萃取行为变化的主要原因。     

高效液相色谱法测定清肺化痰丸中苦杏仁苷的含量

采用十八烷基硅烷键合硅胶(200mm×4.6mm,5μm)为固定相,以甲醇∶水(14∶86)为流动相,在214nm波长测定苦杏仁苷。苦杏仁苷在0.25—1.50μg范围内线性关系良好(r=0.99997),回收率为100.04%(RSD为1.12%)。该方法简便准确,重复性好,处方中其他成分对测定无干扰,可作为本产品的质量控制方法。     

First light on the 127-element adaptive optical system for 1.8-m telescope

A 127-element adaptive optical system has been developed and integrated into a 1.8-m astronomical telescope in September 2009.In addition,the first light on a high-resolution imaging for stars has been achieved（September 23,2009）.In this letter,a 127-element adaptive optical system for 1.8-m telescope is described briefly.Moreover,star observation results in the first run are reported.Results show that the angular resolution of the system after adaptive optics correction can attain 0.1 arcsec,which approaches the diffraction limit of 1.8-m telescope at 700-900 nm band.