城市污水处理过程中有机污染物三维荧光特性的变化规律

采用三维荧光光谱法研究了城市污水处理过程中溶解性有机物的三维荧光特性变化规律。研究结果表明,生活污水中荧光类溶解性有机物主要以类蛋白有机物、UV腐殖质和可见腐殖质为主;污水生物处理前后特征荧光峰中心位置和强度均发生明显的改变,表明污水中有机物的相对组成和含量随生物处理过程而变化。三维特征荧光参数可以反映污水处理过程中污染物的种类、性质和含量变化等丰富信息。其测定迅速简便、灵敏度高,可用于污水处理效果的定性分析、定量评价,易于实现污水处理过程的实时在线监测,指导污水处理工艺的设计、运行、管理和控制。     

MICRO-PHASE SAEPARATION IN EPOXY RESIN WATERBORNE PARTICLES DURING CURING PROCESS

Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature （Tg） and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.     

Investigation on False Peak Phenomena in On-line Sweeping Technique in MEKC

ＩｎｔｒｏｄｕｃｔｉｏｎＭｉｃｅｌｌａｒｅｌｅｃｔｒｏｋｉｎｅｔｉｃｃｈｒｏｍａｔｏｇｒａｐｈｙ (ＭＥＫＣ)ｗａｓｉｎｖｅｎｔｅｄｔｏｅｘｔｅｎｄｔｈｅｕｔｉｌｉｔｙｏｆｃａｐｉｌｌａｒｙｅｌｅｃｔｒｏｐｈｏｒｅｓｉｓ(ＣＥ)ａｎｄｐｅｒｍｉｔｔｅｄｔｈｅｓｅｐａｒａｔｉｏｎａｎｄａｎａｌｙｓｉｓｏｆｎｅｕｔｒａｌｃｏｍｐｏｕｎｄｓ .ＢｕｔｊｕｓｔｌｉｋｅｏｔｈｅｒｍｏｄｅｓｏｆＣＥ ,ＭＥＫＣａｒｅｈａｍｐｅｒｅｄｂｙｔｈｅｌｏｗｃｏｎｃｅｎｔｒａｔｉｏｎｓｅｎｓｉｔｉｖｉｔｙｏｆｔｈｅｕｌｔｒａ …     

The theoretical basis of column chromatography in multicomponent separations. Part 2: Peak capacity. Column systems with good selectivity

The selectivity of a column system, S, defined by equation 28, includes a variation coefficient (β) of plate number with capacity ratio which has a large influence on the peak capacity, as shown in Fig. 18. Some typical chromatograms are given. In order to predict S for a column system from Kovat's Index, equations 40 and 41 are given to calculate the constant of the carbon number rule for squalane at different temperatures or for different stationary phases. The specific retention value of heptane on squalane at different temperatures can be calculated from equation 42. The nonpolarity index, defined by equation 43, was used to calculate the retention value of heptane on various stationary phases. In liquid chromatography, the order of elution may be reversed by changing the composition of the eluent on the same chemically bonded silica (manufactured in China). The linear relations between the log retention values of different kinds of solutes or of a single solute on the silicas of different surface areas when using the same eluent are given.     

校正峰电位漂移偏最小二乘极谱催化波同时测定轻稀土

应用Ｍ２７３．Ａ电化学系统中的线性扫描技术，确定了８．０×１０－５ｍｏｌ／Ｌ二甲酚橙及ｐＨ４．０ＨＡｃ－ＮａＡｃ缓冲体系为偏最小二乘极谱法同时测定Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｓｍ、Ｅｕ的最佳极谱体系。６种稀土元素的线性范围均在１．０× １０－７～１．２ × １０－５ｍｏｌ／Ｌ。并对极谱峰电位随浓度漂移进行了校正，提高了方法的准确度。     

Implementation and efficiency of an automatic peak-purity-control procedure in HPLC-UV-VIS-coupling based on principal component analysis

Summary Based on a thorough knowledge of the actual system precision significance testing of the primary eigen values, resulting from principal component analysis of the two-dimensional data array of HPLC with photodiode-array detection, is a powerful means to uncover unresolved chromatographic peaks. The implementation of this chemometric technique for assuring peak homogeneity and results showing the efficiency for two-component peaks in regard to spectral characteristics, chromatographic resolution and absorbance ratio of the investigated compounds are presented.     

Underpotential deposition studies of copper on glassy carbon

Studies on the deposition and dissolution of copper from 0·5 M sulphuric acid solutions onto glassy carbon (GC) using potential sweep techniques indicated that an additional peak occurs at higher positive potentials than the bulk stripping peak. This peak is identified as due to the stripping of underpotential deposited (UPD) copper. Results of investigations on the effect of sweep rate, deposition potential and time of deposition on the peak characteristics of UPD and bulk deposited copper are also reported.     

Error estimation in peak‐shape analysis of XPS core‐level spectra using UNIFIT 2003: how significant are the results of peak fits?

An error analysis for numerically evaluating random uncertainties in x‐ray photoelectron spectroscopy has been implemented in version 2003 of the spectra treatment and analysis software UNIFIT in order to improve the understanding of the statistical basis and the reliability of the model parameters for photoelectron spectra. The theoretical basis as well as two approaches to obtain error limits of the fit parameters have been considered. Several test spectra have been analysed and discussed. A representative example has been chosen to demonstrate the relevance of the error estimation for practical surface analysis. Suggestions for the minimization of errors in the peak‐fitting procedures are presented. Copyright © 2004 John Wiley & Sons, Ltd.     

DETERMINATION OF DEGREE OF CRYSTALLINITY OF NYLON 1212 BY WIDE-ANGLE X-RAY DIFFRACTION

Based on the X-ray scattering intensity theory and using the approximate expression for the atomic scattering factor, the correction factors for three crystalline peaks and an amorphous peak of Nylon 1212 were calculated and the formula of degree of crystallinity of Nylon 1212 was derived by a graphic multipeak resolution method. The degree of crystallinity calculated from the WAXD method is compatible with those obtained by density and calorimetry methods.     

双峰倍增配平法用于同步、导数-同步荧光法同时测定邻羟基苯甲酸和间羟基苯甲酸

邻羟基苯甲酸（ｏＨＢＡ）和间羟基苯甲酸（ｍＨＢＡ）荧光光谱严重重叠，同步及导数技术虽使选择性有所改善，但仍不能完全分辨开重叠谱。用双峰倍增配平计算法结合同步、一阶导数－同步荧光法对双组分体系（邻羟基苯甲酸／间羟基苯甲酸，ｐＨ１２介质）同时测定。结合计算的两种测定方法精密度、回收率和不同组分间浓度比范围均优于一阶导数－同步荧光法。