Analysis of ochratoxin A and ochratoxin B in traditional Chinese medicines by ultra-high-performance liquid chromatography–tandem mass spectrometry using [C20]-ochratoxin A as an internal standard

The paper reported a reliable analytical method for simultaneous determination of ochratoxin A (OTA) and ochratoxin B (OTB) in traditional Chinese medicines (TCMs) by ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS). The development of the method and investigations on the matrix influence were described in particular. The matrix effects were thereby minimized by using a reliable internal standard and a simple sample pretreatment. The established method was further validated by determining the linearity (R² ≥ 0.9990), average recovery (86.3–114.2%), sensitivity (limit of quantitation 0.03–0.19 ng mL⁻¹) and precision (relative standard deviation ≤ 13.1%). It was shown to be a suitable method for simultaneous determination of OTA and OTB in various TCMs. Finally, a total of 51 TCMs widely used in China were screened for OTA and OTB with the proposed method. The results showed that only 4 samples were contaminated with ochratoxins at low levels, indicating that it was low risk of ochratoxins to consumers who occasionally used TCMs.     

全自动食品甲醛分析仪的研制及应用

将超声提取、过滤和流动注射装置耦合,由自行设计的集成电路和软件控制,研制了一种全自动食品甲醛分析仪,实现了样品中甲醛提取—过滤—检测的连续自动化。利用在强碱性条件下,甲醛与间苯三酚快速发生显色反应,建立了测定食品中甲醛含量的测定方法,方法线性范围为0.5～20.0μg/mL,检出限为0.04μg/mL。用该法对水发海参、水发鸡爪、鹅肠和牛百叶样品进行了测定,测定结果在0.28～0.76μg/g之间(u=2,95%置信水平),样品加标回收率为88.7%～104%。该法适用于现场样品的快速测定。     

Application of quantitative structure-activity relationship to the determination of binding constant based on fluorescence quenching

Quantitative structure-activity relationship (QSAR) model was used to predict and explain binding constant (log K) determined by fluorescence quenching. This method allowed us to predict binding constants of a variety of compounds with human serum albumin (HSA) based on their structures alone. Stepwise multiple linear regression (MLR) and nonlinear radial basis function neural network (RBFNN) were performed to build the models. The statistical parameters provided by the MLR model (R²=0.8521, RMS=0.2678) indicated satisfactory stability and predictive ability while the RBFNN predictive ability is somewhat superior (R²=0.9245, RMS=0.1736). The proposed models were used to predict the binding constants of two bioactive components in traditional Chinese medicines (isoimperatorin and chrysophanol) whose experimental results were obtained in our laboratory and the predicted results were in good agreement with the experimental results. This QSAR approach can contribute to a better understanding of structural factors of the compounds responsible for drug-protein interactions, and can be useful in predicting the binding constants of other compounds.     

Cs(6D5/2)+H2→CsH[ X1Σ+(v,J)]+H转动分辨总截面的测量

利用泵浦-检测方法,在样品池条件下,研究了Cs(6D5/2)与H2反应碰撞传能过程。利用激光感应荧光（LIF）光谱技术,确定了CsH[X1Σ+(v,J)]振转能级上的布居分布,转动态分布与热统计分布基本一致.Cs激发态原子密度由激光能量吸收得到.记录A1Σ+(v',J+1)→X1Σ+(v,J)的时间分辨荧光,从荧光强度的对数值给出的直线斜率确定(v',J+1)→(v,J)的自然辐射率,结合(v,J)→(v',J+1)吸收系数的测量,得到反应生成物CsH[X1Σ+(v,J)]态的分子密度.由速率方程分析,给出反应截面(v,J),对J求和,得到(v)[10-16cm2单位]分别为（0.64±0.19）（v=0）和（0.58±0.17）（v=1）.     

氧分压对Mg掺杂ZnO薄膜结晶质量和光学特性的影响

利用脉冲激光沉积技术,通过改变沉积过程中的氧气压力,在蓝宝石(0001)基片上制备了一系列ZnMgO合金.通过X射线衍射、反射和透射光谱以及室温和变温荧光光谱,对薄膜的结构和光学性能进行了系统地表征,分析了工作气压对ZnMgO合金薄膜的结晶质量及光学特性的影响.研究结果表明:随着沉积环境中氧气压力的增大,ZnMgO薄膜的结晶质量下降,富氧环境下,与蓝宝石晶格平行的ZnO晶粒的出现是导致薄膜结晶质量下降的主要原因;相对于本征ZnO,不同氧气环境下沉积的ZnMgO薄膜的紫外荧光峰均出现了不同程度的蓝移.随着工 关键词： ZnO Mg掺杂 脉冲激光沉积 薄膜生长 光学特性     

Domain structure and optical property of epitaxial indium oxide film deposited on MgO(100) substrate

Indium oxide (In₂O₃) film has been deposited on MgO(100) substrate at 600 °C by metalorganic chemical vapor deposition (MOCVD). The crystal structure and epitaxial relationship of the sample were examined by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The results showed a clear epitaxial relationship of In₂O₃(111)||MgO(100) with In₂O₃[011?]||MgO<072> or In₂O₃[01$\overline{1}$]||MgO<011>. A multiple domain structure was found inside the In₂O₃ film and a theoretical model clarifying the geometrical relationships between each domain and the substrate has been proposed. Scanning electron microscopy (SEM) micrograph showed that the main surface features were triangle-shaped grains on the film. The absolute average transmittance of the obtained film in the visible range was over 93%.     

新疆天山北坡常见盐生植物端元尺度光谱特征及识别

通过野外定点光谱采样,从端元尺度对天山北坡四种常见的盐生植物芨芨草、苦豆子、樟味藜、骆驼刺进行了光谱特征分析和种类识别。结果表明:从CARI和SIPI两个常用的叶绿素高光谱指数来看,骆驼刺的叶绿素含量和类胡萝卜素含量均较高,苦豆子虽然生长旺盛,由于受到光谱中花的因素影响,这两个指数值较低。苦豆子株冠郁闭度较高,其NDVI值高于其他三种植物。苦豆子和樟味藜的光谱位置参数较稳定,而芨芨草和骆驼刺则既存在BEP红移,也存在REP蓝移,红边和蓝边变化幅度较大。生长旺季中不同植物端元光谱曲线之间差异较小,存在明显的混合光谱现象,利用遥感常用的红/近红外特征空间难以准确区分樟味藜和骆驼刺。采用逐步多元判别分析,筛选出Rn,REP,Rg,MSAVI和CARI作为判别指标构建判别方程,芨芨草和樟味藜可以100%被识别,四种植物的判别总精度达92%以上。     

ERROR ESTIMATION FOR NUMERICAL METHODS USING THE ULTRA WEAK VARIATIONAL FORMULATION IN MODEL OF NEAR FIELD SCATTERING PROBLEM

In this paper, we investigate the use of ultra weak variational formulation to solve a wave scattering problem in near field optics. In order to capture the sub-scale features of waves, we utilize evanescent wave functions together with plane wave functions to approximate the local properties of the field. We analyze the global convergence and give an error estimation of the method. Numerical examples are also presented to demonstrate the effectiveness of the strategy.     

Large-aperture double-focus laser collimator for PAT performance testing of inter-satellite laser communication terminal

A laser collimator is necessary for testing and verification of the pointing, acquisition and tracking (PAT) performance of inter-satellite laser communication terminals on the ground. The laser collimator must have a large clear aperture to fit the PAT performance testing system. The PAT subsystem has a large field of view for the acquisition and a high angular accuracy for the fine tracking. To resolve the conflict between large field of view and fine angular resolution, a large-aperture double-focus laser collimator is proposed and its optical design and mechanical structure are described. The collimator mainly consists of a primary lens, a reflector, a beam-splitting plate, a secondary lens, two compensating lenses, two imaging sensors and a laser. The primary lens directly forms the long focal length arm of the collimator. The combination of the primary lens and the secondary lens form the short focal length arm of the collimator. The collimator has an angular resolution <0.75 μrad and a 10 mrad field of view. For the collimator, the incident beam is focused on the two imaging sensors by its two arms, and the beam emitted from the laser is collimated and transmitted. The collimator is combined with an optical scanner and a fine beam deflector to test and verify the PAT performance of the inter-satellite laser communication terminal in a full physical manner.     

侧面预电离氟化氪激光器研制

采用侧面紫外火花隙自动预电离代替小极上小孔预电离，使放电泵浦氟化氪激光器的主放电均匀性大为改善。输出激光能量由１４０ｍＪ提高到２５０ｍＪ，增益区光能密度为２．３Ｊ／１，同时电极寿命和气体寿命也大为提高。