海红果酒中甲醇比色测定条件优化

针对比色法测定海红果酒中甲醇标准曲线线性差的问题，通过单因素实验，对影响甲醇测定的4个主要因素进行了研究，最佳的测定条件为：草酸一硫酸溶液用量为0．6mL，无甲醇的乙醇溶液浓度为40％，静置时间为13min，显色温度为40℃，在此条件下甲醇标准曲线的R^2值为0．997．     

Scintillation properties of YAG:Yb crystals

We report on measurements of the light yield, emission spectrum, and time response of YAG:Yb crystals. The temperature dependence of light yield was investigated. Data show that YAG:Yb crystals are good scintillators, suitable for applications to neutrino detection and spectroscopy.     

Photocatalytic decomposition of methyl tert-butyl ether in aqueous slurry of titanium dioxide

The photocatalytic degradation of methyl tert-butyl ether (MTBE) was investigated in the aqueous slurry of titanium dioxide (TiO₂) particles irradiated with xenon lamp in a batch reactor. The reaction was found to follow a pseudo-first-order kinetics and the reaction rate increased by raising the TiO₂ loading and the UV light intensity. The reaction rate constant was proportional to the square root of the UV intensity. An upper plateau level was observed for the reaction rate constant, corresponding to a steady photoproduction of hydroxyl radicals at high catalyst concentrations. The experimental data was analyzed using a modified Turchi–Ollis model to account for changes in the catalyst loading. It was found that this model predicted the observed trend in the pseudo-first-order rate constant if the reaction pathway involves the interaction between adsorbed hydroxyl radicals and solvated molecules.     

Micellar Liquid Chromatography and Derivative Spectrophotometry for the Simultaneous Determination of Acemetacin and Chlorzoxazone in their Tablets and Human Plasma

Two accurate analytical methods were developed for the resolution and analysis of a binary mixture of acemetacin (ACE) and chlorzoxazone (CLZ). The first method depends on chromatographic separation of ACE and CLZ using a Shimadzu VP-ODS column. Mobile phase containing 0.075 M sodium dodecyl sulphate, 0.3% triethylamine, 10% n-propanol in 0.02 M orthophosphoric acid of pH 5.5 was pumped at a flow rate of 1 mL/min. with UV detection at 210 nm. The method was further extended to the determination of acemetacin (ACE) and chlorzoxazone (CLZ) in spiked human plasma without prior extraction. For the second method, it depends on measuring the amplitudes of the first derivative spectra at 281.75 nm for ACE and 242.53 nm for CLZ.     

分光光度法测定水产品中二氧化硫残留量

本文建立了测定水产品中二氧化硫残留量的分光光度法,在酸性条件下蒸馏通过盐酸副玫瑰苯胺显色,可以快速、准确检测水产品中的二氧化硫残留量。     

Variation in essential,trace and toxic elemental contents in Murraya koenigii – A spice and medicinal herb from different Indian states

Curry leaves (Murraya koenigii), collected from 19 different Indian states, were analyzed for six minor (Ca, Cl, K, Mg, Na and P) and 20 trace (As, Ba, Br, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mn, Rb, Sb, Sc, Se, Sr, Th, V and Zn) elements by instrumental neutron activation analysis (INAA). In addition, Ni, Cd and Pb were determined by atomic absorption spectrophotometry (AAS). Most elements vary over a wide range, depending on geo-environmental factors and local soil characteristics. Fe, Mn, Na, K, Rb, Se and P vary by a factor of 3–5 whereas Br, Cs, Sc, Th and Zn vary by an order of magnitude. Leaves collected from the southern zone were enriched in K, Mg, Mn, Cl and P but depleted in Se. However, leaves from the northern zone were particularly enriched in Ca whereas those from the western zone were enriched in Zn. Concentrations of most elements from the eastern zone were on par with the mean values. Cr, Fe, Cu, V and Zn are known to play an important role in the maintenance of normoglycemia by activating β-cells of pancreas. Percent contributions of diabetically important elements from curry leaves were 1–2% of daily dietary intake (DDI) but are likely to be in bioavailable form thus making them effective for treatment of diabetes. Rb and Cs are linearly correlated (r = 0.93) as their salts enhance the absorption of insulin in the lower respiratory tract by breakdown of glucose. Inorganic elements may remain complexed with organic ligands.     

Degradation of the N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine by photon irradiation

The increase of operational lifetime for Organic Light-Emitting Diodes has stimulated many studies focused on the mechanisms responsible for their degradation. Degradation studies of the N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine thin films have been performed using synchrotron radiation in order to elucidate the modification of the electronic structure in such organic compound, when non-monochromatized light was used to simulate the degradation caused by intense sunlight. Core level photoabsorption at the N 1s-edge and valence level photoemission measurements suggest stronger structural stability and a minor loss in the hole transporting properties. The degradation leads to the decrease of the injection and charge mobility, associated with the loss of nitrogen and benzene rings, which causes an increase of the impedance in the electroluminescent device.     

克拉霉素和茜素在甲醇中的荷移反应

研究了克拉霉素和茜素在甲醇介质中的电荷转移反应 ,确定了最佳反应条件。研究表明 ,克拉霉素和茜素在甲醇中生成 1∶1型荷移配合物 ,该配合物的λmax=5. 34nm ,表观摩尔吸光系数ε =3 .79× 10 .3 L·mol-1·cm-1,克拉霉素浓度在12 . 8～ 180mg/L范围内符合比尔定律。     

废水中S^2-含量的间接光度法测定

在弱酸性(醋酸-醋酸钠缓冲溶液，pH值4．0)介质中，Cu^2 与废水中的S^2-发生完全定量化学反应，过量的Cu^2 与1-(2-吡啶偶氮)-2-萘酚形成稳定的配合物，用光度法检出，从而实现工业废水中S^2-的间接测定。该配合物在λmax-552m处有最大吸收。用于测定废水中的S^2-含量，回收率为98．7％～101.0％，灵敏度和选择性都能达到要求。     

Methods of selecting a small reflectance set as a transfer standard for correcting spectrophotometers

The present article concerns the use of software and transfer standards of reflectance to correct a fielded spectrophotometer so that it behaves closely like a reference instrument. A method is described to choose from a large set of reflectances the best subset of a few reflectances to act as a transfer standard. A reflectance set is generated from the algorithm using each of two alternative metrics for instrument closeness: CIELAB ΔE* and a weighted sum of absolute differences over wavelength. Both metrics yield transfer standards that conspicuously exclude BCRA reflectances and also show improvement over the BCRA reflectances currently used for this purpose. © 2005 Wiley Periodicals, Inc. Col Res Appl, 31, 13–17, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20169