测量介同波吸收的实验研究

利用微波分光仪测量介质板的微波吸收系数,考虑了接收器和介抽板对微波的反射影响,沿波传播方向移动介质板的位置来测量同波强度的极大值和极小值,以它们的平均值作为透射波的强度。还考虑了介质板两个界面的反射对入射波强度的影响。     

金属材料的激光吸收率研究

针对菲涅耳公式计算金属材料激光吸收率所得的结果与实际测得的吸收率值存在一定的误差这一问题,在详细分析了激光热处理中金属材料吸收率影响因素的基础上,通过数值模拟,改进了金属材料激光吸收率的计算模型,并利用此激光吸收率计算模型(以铝、铜、铂、铁4种金属材料为例)进行激光吸收率的计算和分析,进而计算了3Cr13不锈钢激光吸收率的理论值,该值与用集总参数法测得的3Cr13不锈钢材料激光吸收率结果相吻合,从而验证了该改进的金属材料激光吸收率计算公式的正确性。     

EPR and electronic spectral properties of aryl-substituted bis(dithiophosphato)copper(II) complexes

The spectral properties of bis(diaryl-dithiophosphato)copper(II) complexes, [Cu(S(2)P(OR)(2))(2)], with R = o-cresyl (complex I) and 2,6-dimethylphenyl (complex II) are studied by EPR- and vis spectroscopy. In solid (powder) state both complexes exhibit dark brown colour and are paramagnetic. Room temperature EPR spectra of the complexes dissolved in non-coordinating (C(6)H(5)CH(3), C(5)H(12), C(6)H(14)), acceptor (CHCl(3), CCl(4)) or donor (DMFA, DMSO) solvents have typical features of the chromophore CuS(4). In non-coordinating and acceptor solvents their isotropic EPR parameters are: g(iso)=2.047+/-0.003, (Cu)A(iso) = 7.2+/-0.1 mT and (P)A = 0.95+/-0.1 mT. An absorption band characterizes the vis spectra in these solvents with a maximum at 427 nm, due to a ligand-to-metal charge-transfer transition. One hour after dissolution the absorbance at 427 nm follows Beer's law with molar absorptivity (epsilon) about 11000, which does not change significantly after 24 h staying at room temperature or after 30 min heating at 50 degrees C. Both DMFA and DMSO exhibit specific solute-solvent interaction with the acceptor centre of copper complex yielding an axial adduct, with increased g-factor and decreased (hf)A compared to the initial complex. An additional EPR signal with unresolved hyperfine structure is also detected in DMSO. EPR and vis intensities of both bis(diaryl-dtp)Cu(II) complexes decrease after dissolution in both solvents. Moreover, they are EPR silent in pyridine and do not show any absorption in the vis spectra.     

Quantitative Characterization of the Molecular Absorption Spectra in the Ultraviolet Region by Gas Chromatography

The aim of this study was to obtain quantitative characteristics of the ultraviolet absorption spectra as the molecular absorptivity at the wavelength of maximum absorbance. Organic as well as inorganic compounds were explored. A gas chromatography—ultraviolet absorption instrument has been used in the quantitative study of molecular ultraviolet absorption spectra in the vapour phase. The wavelength range studied was between 168 and 330?nm. The absorbance of 170 compounds was determined relative to perchloroethylene and their molecular absorptivities were calculated. For various groups of compounds, these relative absorptivities varied within two to three orders of magnitude. Standard curves were linear within four orders of magnitude from limit of quantification up to an absorption value of 1.5 absorbance units. The noise level was 3?×?10^?5 absorbance units peak to peak at a bandwidth of 1.7?nm and a wavelength range from 180 to 330?nm was preferred. The detection limit for mesitylene was calculated to be 2 pg/s and for naphthalene 1 pg/s with 4?s store cycle time.     

Laser assisted decontamination of metal surface: Evidence of increased surface absorptivity due to field enhancement caused by transparent/semi-transparent contaminant particulates

Small signal absorption measurements of the incident coherent radiation by the metal surface have revealed an increase in the absorption by the surface in presence of transparent/semi-transparent particulates on it. This effect, identified as field enhanced surface absorption, has been found to increase with reduction in the average particulate size. Consequently higher laser assisted removal efficiency of contamination from a metal surface has been observed for smaller contaminant particulates. These measurements have been carried out utilizing coherent radiations of two different wavelengths so chosen that for one the particulates are totally transparent while for the other they are partially transparent.     

Calibration of Circular Dichrometers in the Visible Region

Abstract

The cesium salt of R, R-(-)-trans-l, 2-cyclohexane-diaminetetraacetatocobaltate(III), Δ-(+)₅₄₆-Cs[Co(R, R(-)-CDTA)], Δ-Cs[Co(R, R(-)CDTA)]), provides a compound which can be used for calibration of circular dichrometers in the visible region. Δ-Cs[Co(R, R(-)CDTA)] has three major circular dichroism (CD) maxima at 593 nm, 527 nm, and 240 nm. The molecular ellipticities, [θ], at 593 nm, 527 nm, and 240 nm are -4490 ± 40, 5720 ± 40, and -47, 900 ± 300 deg cm² dmol^?1, respectively. The CD maxima in terms of Δε at 593, 527, and 240 nm are -1.36 ± 0.01, 1.73 ± 0.01, and -14.5 ± 0.1 l cm^?1 mol^?1, respectively. Optical rotatory dispersion (ORD) and ultraviolet-visible absorption data has also been obtained for this compound.     

紫外-可见分光光度计的应用与维修

主要介绍了TU1221型紫外-可见分光光度计的原理、应用及维修,对错误代码NG1、NG2、NG8、NG9等常见故障现象进行了原因分析与排除.     

Calculation of the molar absorptivity of polyphenols by using liquid chromatography with diode array detection: the case of carnosic acid

Antioxidant activity of vegetable extracts is related to the nature and the amount of active components, mainly polyphenols; therefore, a correct quantification of these molecules should be required to define their concentration in such kind of vegetable extracts. A fast and accurate method to calculate molar absorption coefficients (epsilon), by using HPLC, has been tested on standard polyphenols and caffeine, and should be widely adapted for standardless quantitative analysis. Molar absorptivity (epsilon) of carnosic acid (CA) was determined from 200 to 300 nm, by the proposed method and those values were compared to tert-butyl-hydroxytoluene (BHT) ones for further comparative quantification.     

Determination of the Molar Decadic Absorptivities of the Stretching Vibrations of the Hydride and Phenyl Groups on Aerosil® 300

 The hydride and phenyl groups on the silica surface were determined qualitatively and quantitatively. The calculation of the molar decadic absorptivities of the Si*H-stretching vibration band at 2293 cm⁻¹ and of the C*H-stretching vibration band at 3068 cm⁻¹ was carried out according to Lambert-Beer’s law.     

在CPB 存在下偶氮氯膦一间磺酸基苯与稀土元素显色反应的研究

本文报道了新显色剂偶氮氯膦-间磺酸基苯在表面活性剂(CPB)存在下与稀土元素的显色反应具有较高的灵敏度和选择性。通过实验研究了多元络合物的吸收光谱、络合物的组成以及反应的最佳条件。用本方法测定了实际样品中的稀土总量,获得了满意的结果。