快速去除硝酸和亚硝酸对氢化物发生原子荧光法测定砷的干扰

为了避免繁琐、耗时的"赶酸"操作, 研究了尿素结合NaOH除去微波消解液中过量的HNO3和HNO2的干扰,继用L-半胱氨酸在低酸度下将As(Ⅴ)还原为As(Ⅲ)的样品消化和预还原方法.用氢化物发生-原子荧光法准确、快速地测定了食品中痕量砷.该方法的检出限为0.03 μg/L;连续11次测定4 μg/L As(Ⅲ)标准溶液的相对标准偏差为1.6%; 测定国家标准物质的结果与标准值非常吻合.     

(R)-乙基-2-吡啶亚砜与(4R,5R)-TADDOL包结晶体 [C7H9NOS·C31H30O4]的晶体结构分析

（Ｒ）－乙基－２－吡啶亚砜与（４Ｒ，５Ｒ）－二（羟基－二苯基－甲基）－２，２－二甲基－１，３－二氧戊环（ＴＡＤ－ＤＯＬ）可以形成物质的量比为１∶１的手性包结晶体，Ｘ射线衍射分析确定该晶体属单钭晶系，Ｐ２１空间群，ａ＝０．９７０１（２）ｎｍ，ｂ＝０．９９５３（２）ｎｍ，ｃ＝１．７３９２（２）ｎｍ；β＝９２．０７９°（１４），Ｖ＝１．６７８１（５）ｎｍ３，Ｚ＝２，Ｄｃ＝１．２３０ｇ／ｃｍ３，分子式Ｃ３８Ｈ３９ＮＯ５Ｓ，Ｍｒ＝６２１．７６，最终偏离因子Ｒ＝０．０３５１，ＲＷ２＝０．０７７２，Ｆｌａｃｋ值为０．１（２）．结构分析表明，主客体存在分子间氢键．光学纯的ＴＡＤＤＯＬ与消旋的乙基吡啶亚砜（１）作用时，ＴＡＤＤＯＬ对１具有很好的手性识别能力，选择性地与１的一个对映体形成氢键，长成晶体．参照晶体结构确定了１的两个对映体的绝对构型     

会理益门煤矿自备发电厂排污现状监测研究

以国标法为检测标准,对会理益门煤矿煤矸石发电厂进行排污现状监测与检测。通过现场监测、室内分析和数据处理表明:会理益门煤矿自备发电厂处理后的废水各项指标均达到国家《污水综合排放标准》(GB8978-1996)一级排放标准要求;处理后的废气(SO_2)、烟尘的排放浓度均符合国家《火电厂大气污染物排放标准》(GB13223-2003)第3时段煤矸石电站排放标准;厂界噪声各测点的昼夜监测值符合国家《工业企业厂界噪声标准》(GB12348-90)Ⅱ类标准要求。     

Prediction of thermal conductivity of polymer-based composites by using support vector regression

Support vector regression (SVR) combined with particle swarm optimization (PSO) for its parameter optimization, was proposed to establish a model to predict the thermal conductivity of polymer-based composites under different mass fractions of fillers (mass fraction of polyethylene (PE) and mass fraction of polystyrene (PS)). The prediction performance of SVR was compared with those of other two theoretical models of spherical packing and flake packing. The result demonstrated that the estimated errors by l...     

非球对称星风中尘埃的形成

通过建立非球对称星风模型,研究了恒星尘埃的生成,发现在非球对称模型中,恒星更早地生成尘埃.对于较低的质量损失率,由非球对称模型给出的尘埃凝结度远远高于由球对称模型给出的尘埃凝结度.因而,非球对称模型可能给出更高的尘埃产量.对于较高的质量损失率,由于尘埃的凝结度已达到饱和,非球对称模型和球对称模型下,尘埃的凝结度基本一致,对尘埃的产量不会产生大的影响.     

工程测量中光波干涉必须满足的几个条件

讨论了两列光波发生干涉现象的理想化条件和在实验中能否观察到干涉现象发生的操作性条件，推导了各种情况下的理论公式。从工程应用的角度出发，研究了检测仪器的响应时间T和光强分辨能力对观察光的干涉现象的影响，提出了观察光的干涉现象的第四个必要条件，对在各种情况下应用光的干涉现象有一定的指导作用。     

BEHAVIOR OF CHO CELLS ON MODIFIED POLYPROPYLENE BY LOW TEMPERATURE AMMONIA PLASMA

1. INTRODUCTION Bioreactors using membranes as substrates of cell cultures have become widely used for hybrid liver support systems [1]. For enhancing and prolonging the metabolism of the bioreactors, cytocompatible membranes are necessary because the cell culture is closely affected by the substrate surface. Surface factors considered to be important in cell culture are the concentration of ionic groups, the nature of polar and non-polar groups and the hydrophilic-hydrophobic balance [2].…     

A method for detecting target echo in reverberation based on fractional Fourier transform

A method for detecting the target echo in reverberation was proposed based on fractional Fourier transform theory when the transmitted signal is linear frequency modulation signal. The slow time-varying envelope of reverberation is computed to process reverberation to be stationary. The stationary reverberation is cut into blocks using a sliding window. A narrow-band filter is applied in FrFT domain for each block and the signal is recovered through inverse FrFT. Output of the system is the energy of the recovered signal. When the target echo is included in one of the blocks, the reverberation noise is reduced, and the output is the energy of the target echo. All the simulation and lake experiment results show that the detection performance of the present method is better than that of the matched filter.