太阳CO 4.6微米红外成像观测

太阳红外光谱中蕴含着丰富的物理信息,其中CO 4.6μm波段是具有代表性的分子谱带,其形成于温度极小区附近,对研究太阳物理具有极其重要的意义。为获得CO 4.6μm波段太阳单色像,本文建立了一套全反射太阳红外成像观测系统。该系统采用定天镜跟踪引光,通过成像反射镜将太阳成像于3~5μm波段红外相机的焦平面上,该相机采用的是国产HgCdTe焦平面阵列器件。同时,为提高信噪比,提出了一种有效计算平场提取观测目标的方法,并利用该方法获得了CO 4.6μm波段的太阳单色像。     

多巴胺和5-羟色胺的毛细管电泳测定

建立了高效毛细管电泳结合柱上紫外检测测定单胺类神经递质多巴胺(dopamine,DA)和5_羟色胺(5_hydroxytryptamine,5_HT)的毛细管电泳方法 ,优化了缓冲液 pH值、浓度、电压等实验参数 ;结果表明 ,在优化的实验条件下 ,多巴胺、3,4_二羟苄胺 (3,4_dihydroxybenzylamine)和5_羟色胺在10min内得到很好的分离 ,检出限分别为2.02×10 -5mol/L,1.01×10 -5mol/L,1.20×10 -5mol/L ;该法简便、快速 ,样品用量少 ,结果准确 ,重现性好     

Millimeter and submillimeter detection using Ga1?xAlxAs/GaAs heterostructures

We have shown that a Ga_1–xAl_xAs/GaAs heterostructure can be used as a sensitive tunable detector of mm-wave/sub-mm-wave radiation. The mechanism for detection requires the application of a magnetic field varying from approximately 0.2T at 94GHz (3.2mm wavelength) to 6.2T at 2500GHz (119m wavelength). The responsivity and N.E.P. at 3.2mm have been roughly estimated at 200V/W and 5×10^–11W/Hz respectively. The speed of such a detector could be several orders of magnitude greater than comparable InSb detectors.     

Rapid analysis of triterpenic acids by liquid chromatography using porous graphitic carbon and evaporative light scattering detection

An original system which uses Porous Graphitic Carbon as support and a mixture of organic solvents as mobile phase is proposed for the analysis of triterpenic acids by liquid chromatography. The separation of betulinic acid, ursolic acid, oleanolic acid, and 18alpha- and 18beta-glycyrrhetinic acids was carried out within a short time and monitored by evaporative light scattering detection as universal detection method. Molecular modelling studies show that the main contribution to the selectivity comes from the electrostatic interaction characterised by the dipole moment of the products.     

Volatile phase profiling of mainstream smoke by glass capillary gas-chromatographic techniques

A heated injection system for a microprocessor-controlled GC has been developed for the (GC)² analysis of the volatile phase of whole smoke of a cigarette. Effects of injection port temperature and the presence of a Cambridge filter pad are demonstrated. Chromatograms are shown for smoke samples with and without a Cambridge Filter with the sample valve oven at 25°, 165° and 205°C. The use of a flame ionization and a nitrogen-phosphorous detector is illustrated.     

A photometric detector driven by beta radiation

It was recently found that typical Chromatographic carrier gases such as argon or nitrogen could be used in a modified flame photometric detector for general or selective determination of eluted molecules. The detector was powered not by a flame but by a radioactively stimulated, mild discharge. The luminescence arose from the second positive system of nitrogen (in argon), and various emissions from aroyl-containing molecules (in nitrogen).This study describes experiments that take away not only the flame but also the discharge: The energy that produces the luminescence is derived solely from the beta decay of⁶³Ni. Because of this low power input, the sensitivity of the present beta-driven photometric detector (-PD) is limited to about 25 ppm of nitrogen (in argon), and to about 5 pg/s for benzaldehyde and other well-responding aroyl compounds (in nitrogen). In accordance with mechanisms postulated earlier, other types of molecules do not produce significant responses in the absence of an electrical field.Material taken from doctoral thesis     

利用压电频移法测定水中的痕量亚硝酸盐

提出了利用压电频移法测定亚硝酸盐的方法。方法以碘离子与亚硝酸根之间的氧化还原反应为依据，通过测定由反应生成的碘所引起的压电晶体频率的变化，在被萃取水相中亚硝酸盐浓度为０．００９￣２．３ｍｇ／Ｌ范围内，频移值与浓度成正比：ΔＦ＝５．８＋２．５×１０＾３Ｃ（ｍｇ／Ｌ），ｒ＝０．９９０１。方法简便，用于天然水中亚硝酸盐的测定，结果令人满意。     

Hypercoulometric effect in an electron capture detector polarized with an additional voltage

Summary This paper reports measurements of the current characteristics and of the signal corresponding to a constant concentration of Freon F-11 for an electron-capture detector, supplied with a pulse voltage with a changeable pulse duration, amplitude and repetition time. It was found that an additional voltage applied to the detector cathode increased the detector signal by about 50% and that the maximal signal was observed at 5 V. The influence of the polarized voltage on the electron caputure efficiency coefficient (p) measured with two detectors in series was demonstrated and the reliability of the sample mass calculation by means of (p) is discussed.     

Partial least-squares regression and fuzzy clustering — A joint approach

Chemical and physical analyses of malt, the main ingredient of beer, have been used to predict the concentration of certain volatile compounds in the finished beer.The prediction was done by means of the partial least squares regression (PLS2) in SIMCA. The total data set as well as individual malt clusters were submitted to PLS analysis. Best prediction was obtained by separating the total object matrix in classes according to similarity found by fuzzy pattern recognition (FCV). FCV was also used to separate the beer variables in classes and to select the subset of variables to be predicted.A joint approach of fuzzy pattern recognition to identify groups of samples and SIMCA-PLS2 to predict several dependent variables is suggested as a powerful tool in process-analytical chemistry.     

Voltammetric Detector for Liquid Chromatography: Determination of Triclosan in Rabbit Urine and Serum

A flow-electrolytic cell containing a strand of carbon fibers has been designed and characterized for use in a voltammetric detector for high-performance liquid chromatography. The detector was used for determination of triclosan (2,4,4-trichloro-2-hydroxydiphenyl ether) in rabbit serum and urine. Analysis of rabbit serum and urine 1 day and 1 to 5 days, respectively, after ingestion of oral triclosan revealed that the concentration of triclosan was higher than for control serum and urine. The concentration reached maximum levels after 6 h and 34 h or 44 h in serum and urine, respectively. When triclosan was determined in rabbit samples with the method proposed the results obtained were comparable with those obtained by high-performance liquid chromatography with ultraviolet detection.