A solid-phase microextraction fiber coated with diglycidyloxycalix[4]arene yields very high extraction selectivity and sensitivity during the analysis of chlorobenzenes in soil

A novel fiber coated with novel sol-gel (5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-diglycidyloxycalix[4]arene/hydroxy-terminated silicone oil; diglycidyloxy-C[4]/OH-TSO) was prepared for use with headspace solid-phase microextraction (HS-SPME) combined with gas chromatography (GC) and electron capture detection (ECD), which was applied in order to determine nine chlorobenzenes in soil matrices. Due to the improved fiber preparation, which increases the percentage of calixarene in the coating, the new calixarene fiber exhibits very high extraction selectivity and sensitivity to chlorine-substituted compounds. Various parameters affecting the extraction efficiency were optimized in order to maximize the sensitivity during the chlorobenzene analysis. Interferences from different soil matrices with different characteristics were investigated, and the amount extracted was strongly influenced by the matrix. Therefore, a standard addition protocol was performed on the real soil samples. The linear ranges of detection for the chlorobenzenes tested covered three orders of magnitude, and correlation coefficients > 0.9976 and relative standard deviations (RSD) < 8% were observed. The detection limits were found at sub-ng/g of soil levels, which were about an order of magnitude lower than those given by the commercial poly(dimethylsiloxane) (PDMS) coating for most of the compounds. The recoveries ranged from 64 to 109.6% for each analyte in the real kaleyard soil matrix when different concentration levels were determined over the linear range, which confirmed the reliability and feasibility of the HS-SPME/GC-ECD approach using the fiber coated with diglycidyloxy-C[4]/OH-TSO for the ultratrace analysis of chlorobenzenes in complex matrices.

4-ps passively mode-locked Nd : Gd0.5Y0.5VO4 laser with a semiconductor saturable-absorber mirror

We have demonstrated a passively mode-locked diode end-pumped all-solid-state laser, which is composed of a Nd:Gd0.5Y0.5VO4 crystal and a folded cavity with a semiconductor saturable-absorber mirror grown by metal-organic chemical-vapor deposition. Stable cw mode locking with a 3.8-ps pulse duration at a repetition rate of 112 MHz was obtained. At 13.6 W of the incident pump power, a clean mode-locked fundamental-mode average output power of 3.9 W was achieved with an overall optical-to-optical efficiency of 29.0%, and the slope efficiency was 38.1%. (C) 2004 Optical Society of America.

杯[4]芳烃配位和超分子化学的研究

本论文依据主客体作用原理，从分子工程出发，主要利用各式杯芳烃主体与不同客体分子和金属离子进行组装，研究这类超分子的合成条件及规律，探讨主客体之间的相互影响及其自组装原理。 在第二章中，首先研究了银氨离子可诱导杯[4]芳烃(L1)形成超分子胶囊，接下来的工作中，我们对杯[4]芳烃进行修饰，合成了两种杯芳烃羧酸配体25, 26, 27, 28-tetrakis(carboxy methoxy)-calix[4]arene (L2) 和25, 26, 27, 28-tetrakis(carboxy methoxy)-p-t-butylcalix[4]arene (L3)；并分别以六次甲基四胺和三苯基膦为中性配体，构筑了一个由胶囊构筑的三维网络结构和一个四核银的簇合物。 在第三章中，用六次甲基四胺作为中性配体与银离子和对磺酸杯[4]芳烃进行组装，得到了一个纳米孔材料，在该结构中，银与六次甲基四胺形成的配位多聚体作为模板，诱导对磺酸杯芳烃排列形成孔道。由于模板的作用，拉大了杯芳烃之间的距离。 在第四章中，用pnno (pyrazine-N,N’-dioxide)作为客体分子，在稀土离子存在的情况下与杯芳烃进行超分子组装。不同的实验方法分别得到了由超分子胶囊构筑的三维网络结构和A-B-A 的双层结构。稀土Nd与 5,11,17,23- tetrasulfonato- 25,26,27,28-tetra- ethoxycarbonylmethoxyl-calix[4]arene (L4)组装时，得到了一个由氢键连接的层状化合物。 在第五章中，在水溶液条件下，[M(bpdo)22H2O]2+ (M=Zn, Cu; bpdo=2, 2’- bipyridine-N, N’-dioxide )诱导对磺酸基杯[4]芳烃形成超分子胶囊；并且该胶囊通过电荷辅助的π•••π作用与[M(bpdo)3]2+组装成纳米孔材料，气体吸附的测试表明该纳米孔对甲醇有一定气体吸附能力。当用稀土离子代替金属离子时，形成了类似的超分子胶囊和孔状结构。结果表明稀土孔材料比过渡金属孔材料具有更好的热稳定性。进一步研究通过改变配体bpdo为tpdo (tpdo=terpyridine-1, 1’, 1’-trisoxide)得到了一个层状化合物。 在第六章中，将新型的有机配体与丙基焦杯芳烃或甲基间苯二酚杯芳烃进行自组装得到新奇的杯芳烃超分子结构。这些新型的有机配体含有N-O或C=O 官能团的有机分子4,4'-dipyridyl N, N'-dioxide (L5), tetra-2-pyridinyl-N, N', N", N"'-tetraoxide- pyrazine (L6) and 1, 10-phenanthroline-5, 6-dione (L7)。它们是具有特殊的氢键受体和空间构型的有机分子，由于氢键等弱相互作用在形成超分子结构中的重要作用，三种不同的有机配体与杯芳烃自组装得到了三种不同的杯芳烃超分子结构。

Contrastive study of two SESAMs for passive mode-locking in Nd:YVC>4 laser with low pump power

Two semiconductor saturable absorber mirrors (SESAMs), of which one is coated with 50% reflection film on the top and the other is not, were contrastively studied in passively mode-locked solid-state lasers which were pumped by low output power laser diode (LD). Experiments have shown that reducing the modulation depth of SESAM by coating partial reflection film, whose reflectivity is higher than that between SESAM and air interface, is an effective method to get continuous wave (CW) mode-locking instead of Q-switched mode-locking (QML) in low power pumped solid-state lasers. A simple Nd:YVO4 laser pumped by low power LD, in which no water-cooling system was used, could obtain CW mode-locking by the 50% reflector coated SESAM with average output power of ~ 20 mW

4 * 4区域调制多模干涉耦合器SOI光波导开关的设计

根据区域调制多模干涉耦合器光开关的工作原理，以2 * 2区域调制多模干涉光开关为基础，采用级联的方式设计了4 * 4区域调制多模干涉SOI光波导开关。用有限差分二维BPM方法模拟了器件在不同工作状态下的光场传输情况。器件工作波长为1.55 μm，在不计耦合损耗时器件的平均插入损耗小于2.0 dB/cm。

GaAs/Al（0.4）Ga（0.6）As多量子肼红外探测器光吸收计算

于2010-11-23批量导入

一种简易的4.2K低温样品架及其应用

于2010-11-23批量导入