二甲氧基蒽－蒽醌体系分子内激发态复合物形成的结构条件与溶剂效应

本文报道了电子给体二甲氧基蒽（ＤＭＡ）和电子受体蒽醌（ＡＱ）以双酚Ａ（ＢＡ）和对苯二酚（ＯＰ）连接起来的双发色团分子的合成和光谱性质研究，并根据光谱数据和荧光光谱，讨论了激发态复合物形成的结构因素和溶剂效应．     

芳香分子的发光

芳香分子具有属于整个分子的π电子,它决定了芳香分子一般都具有很强的荧光。研究芳香分子的π电子光谱是量子化学的专门课题。常见的理论方法有;Hückel分子轨道理论,Platt环自由电子轨道模型和PPP近似。芳香分子的发光特性决定于分子的结构,例如,分子的刚性、平面性、取代基及其空间特性等等。芳香分子处于蒸汽和单晶状态或溶解在溶剂和固溶体(例如塑料)中,必然发生分子之间的相互作用和能量传递。分子之间的能量传递有多种方式,例如辐射传递、扩散控制过程、激子扩散、共振传递、交换传递和激光的形成与分解等等。     

不同链长二元分子卟啉酞菁(TTP－O－(CH2)n－O－Pc的三阶光学非线

利用简并四波混频(DFWM)方法测量二元分子卟啉酞菁的三阶非线性极化系数X(3)值。得到二元分子卟啉酞菁的X(3)值比它们单元分子卟啉、酞菁的X(3)值大,二元分子卟啉酞菁的X(3)值起初是随链长的增加而增加(Xn=3(3) >Xn=2(3)),链长增至n=3时,X(3)值达到最大值。当链长进一步增加时,二元分子卟啉酞菁的(X(3)值反而下降(Xn=3(3)>Xn=4(3) >Xn=5(3))。这同二元分子中卟啉、酞菁分子由柔性链连接有关。本文对结果给出可能的解释。     

Fluorescence upconversion properties of a class of improved pyridinium dyes induced by two-photon absorption

We report the fluorescence upconversion properties of a class of improved pyridinium toluene-p-sulfonates having donor–π–acceptor (D–π–A) structure under two-photon excitation at 1064 nm. The experimental results show that both the two-photon excited (TPE) fluorescence lifetime and the two-photon pumped (TPP) energy upconversion efficiency were increased with the enhancement of electron-donating capability of the donor in the molecule. It is also indicated that an overlong alkyl group tends to result in a weakened molecular conjugation, leading to a decreased two-photon absorption (TPA) cross section. By choosing the donor, we can obtain a longest fluorescence lifetime of 837 ps, a highest energy upconversion efficiency of 6.1%, and a maximum TPA cross-section of 8.74×10⁻⁴⁸ cm⁴ s/photon in these dyes.     

基于香豆素的比率型荧光探针对溶液及气相中三氟化硼的检测

合成了一种以香豆素为主体的具有高选择性及灵敏性的比率型荧光探针3-对甲基苯基-7-二乙氨基香豆素(TDC), 并将其用于溶液及气相中三氟化硼(BF₃)的即时可视化检测, 检出限为5.5×10^-7 mol/L. 通过荧光光谱、 紫外-可见吸收光谱和核磁共振波谱(¹⁹F NMR)等方法证实, 该探针与BF₃之间发生的路易斯酸碱反应会对TDC分子内电荷转移(ICT)过程产生影响, 从而引起光谱和溶液颜色的明显变化. 基于TDC分子制成的试纸能够实现裸眼检测溶液和气相中的BF₃.     

Output performance of thermally-insensitive passively Q-switched Nd:YAG laser

We study a Cr⁴⁺:YAG Q-switched Nd:YAG laser with a thermally-insensitive corner-cube-prism cavity where the corner cube prism is the key element. The corner cube prism is insensitive to misalignment in any direction. We demonstrate experimentally that a laser cavity with such a prism provides stable laser performance under violent changes of ambient temperature and the effect of the laser crystal thermal lens. The laser mode properties are analyzed by numerical simulations. We show that the numerically simulated results agree well with the experimental ones.     

基于漏波波导X波段高功率微波天线的实验

在确定天线数值模型的基础上,结合高功率微波天线的真空需要与实验装置情况,设计并加工了X波段基于漏波波导的高功率微波天线,对该天线分别进行低功率和高功率条件下的性能指标测试。在低功率条件下天线测试结果表明:在9.6 GHz下天线增益为26.3 dBi,天线方向图与数值模拟结果一致。在SINUS881加速器上利用返波管进行了天线高功率测试,实验结果表明:天线功率容量大于200 MW,高功率测试方向图、低功率测试方向图和数值模拟取得较为一致的结果。     

Rapid and Selective LC�CMS�CMS Method for the Determination of cyclo-trans-4-l-Hydroxyprolyl-l-serine (JBP485) in Rat Plasma

A rapid and selective liquid chromatographic/tandem mass spectrometric method for the determination of JBP485 was developed and validated. Following protein precipitation, the analyte and internal standard (JBP923) were separated from human plasma using an isocratic mobile phase on an Elite Kromasil C18 column. An API 3200 tandem mass spectrometer equipped with a Turbo ionSpray ionization source was used as the detector and operated in the positive ion mode. Multiple reaction monitoring using the precursor to product ion combinations of m/z 201.2 ?? 86.2 and m/z 219.2 ?? 86.2 was performed to quantify JBP485 and JBP923, respectively. The method was linear in the concentration range of 0.10?C50.00 ??g mL^?1 using 100 ??L of plasma. The lower limit of quantification was 0.10 ??g mL^?1. The intra- and inter-day relative standard deviations over the entire concentration range were less than 6.65%. Accuracy determined at three concentrations (0.25, 4.00 and 25.00 ??g mL^?1 for JBP485) ranged from ?0.78 to 2.74% in terms of relative error. Each plasma sample was chromatographed within 2.0 min. The method was successfully applied to characterize the pharmacokinetic profiles of JBP485 in rats after an intravenous injection of 6.25 mg kg^?1 JBP485.     

Study of interaction of butyl p-hydroxybenzoate with human serum albumin by molecular modeling and multi-spectroscopic method

Study of the interaction between butyl p-hydroxybenzoate (butoben) and human serum albumin (HSA) has been performed by molecular modeling and multi-spectroscopic method. The interaction mechanism was predicted through molecular modeling first, then the binding parameters were confirmed using a series of spectroscopic methods, including fluorescence spectroscopy, UV-visible absorbance spectroscopy, circular dichroism (CD) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. The thermodynamic parameters of the reaction, standard enthalpy ΔH⁰ and entropy ΔS⁰, have been calculated to be −29.52 kJ mol⁻¹ and −24.23 J mol⁻¹ K⁻¹, respectively, according to the Van’t Hoff equation, which suggests the van der Waals force and hydrogen bonds are the predominant intermolecular forces in stabilizing the butoben-HSA complex. Results obtained by spectroscopic methods are consistent with that of the molecular modeling study. In addition, alteration of secondary structure of HSA in the presence of butoben was evaluated using the data obtained from UV-visible absorbance, CD and FT-IR spectroscopies.     

Extracts of Punica granatum Linne husk as green and eco-friendly corrosion inhibitors for mild steel in oil fields

Extracts of pomegranate have been investigated, by use of weight loss and potentiodynamic polarization techniques, as green and eco-friendly inhibitors of corrosion of Q235A steel in 1 M hydrochloric acid solution at 60 °C. The efficiency of inhibition by the extracts varied with extract concentration from 10 to 1,000 mg/L; the highest efficiency was 95.0 %. The extracts inhibit corrosion mainly by an adsorption mechanism. In addition, the hydroxyl and ether groups of polyphenols can capture the H⁺ to reduce the corrosion, and the polyphenols can eliminate dissolved O₂ to inhibit oxygen-adsorption corrosion. Potentiodynamic polarization studies show that extracts are mixed-type inhibitors.