水中矿物元素的ICP-MS分析

用ICP－MS对地下水、地表水和饮用水中的矿物元素进行了分析测定，实验证明用ICP－MS可以同时测定地下水，地表水和饮用水中矿物元素；该法灵敏度、精密度和准确度都能满足有关标准的要求，具有多元素同时分析，样品前处理简单，干扰少，测定快速，省事省力等优点。     

二氧化铈还原表面上水煤气变换反应机理

采用原位红外，程序升温脱附，脉冲表面反应技术研究了ＣｅＯ２还原表面在中温变换反应条件下表面物种的生成及脱附，并根据研究结果归纳出水煤气变换反应机理。     

Aqueous solutions—A new perspective. Amorphous carbohydrates: Science and application technology

At a recent meeting of the International Symposium on Solution Chemistry I presented a paper dealing with aqueous solutions in which water was present not in excess but as one component of a supersaturated solution with polyhydroxy compounds. In response to a request from the Editor of this Journal I have submitted this article in which I outline my general interest in the subject and its importance as a new direction for solution chemists.     

难降解有机废水的催化氧化法处理

催化氧化法可通过多种途径来加强传统的化学法处理效果，目前已成为难降解有机废水处理的一项重要新技术。本文介绍了光催化氧化法、均相氧化法、多相氧化法(包括电催化氧化法)以及超临界水氧化技术的国内外研究现状及特点，并对其在有机废水中的应用情况和发展前景作了扼要评述。     

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Multisticker associative polyelectrolytes of acrylamide (≈86 mol %) and sodium 2‐acrylamido‐2‐methylpropanesulfonate (≈12 mol %), hydrophobically modified with N,N‐dihexylacrylamide groups (≈2 mol %), were prepared with a micellar radical polymerization technique. This process led to multiblock polymers in which the length of the hydrophobic blocks could be controlled through variations in the surfactant‐to‐hydrophobe molar ratio, that is, the number of hydrophobes per micelle (N_H). The rheological behavior of aqueous solutions of polymers with the same molecular weight and the same composition but with two different hydrophobic block lengths (N_H = 7 or 3 monomer units per block) was investigated as a function of the polymer concentration with steady‐flow, creep, and oscillatory experiments. The critical concentration at the onset of the viscosity enhancement decreased as the length of the hydrophobic segments in the polymers increased. Also, an increase in the N_H value significantly enhanced the thickening ability of the polymers and affected the structure of the transient network. In the semidilute unentangled regime, the behavior of the polymer with long hydrophobic segments (N_H = 7) was studied in detail. The results were well explained by the sticky Rouse theory of associative polymer dynamics. Finally, the viscosity decreased with an increase in the temperature, mainly because of a lowering of the sample relaxation time. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1640–1655, 2004     

NaBr对C12-s-C12•2Br/氯仿体系中反胶团增溶水能力的影响

近红外(NIR)光谱技术可用于表征氯仿体系中反胶团增溶水的能力. 对于C12-s-C12•2Br (s=2, 3, 4, 5, 6, 8)系列, 不论体系是否含有NaBr电解质, 由于具有较短联接链的表面活性剂易形成较大的反胶团, 其增溶水的能力随着联接链长度增加而降低. 与未含NaBr电解质的体系相比, 当体系中存在NaBr电解质时所形成的反胶团增溶水能力降低.     

Determination of Labile Iron at Low nmol L−1 Levels in Estuarine and Coastal Waters by Anodic Stripping Voltammetry

A new method is presented for the determination of electrochemically labile iron in estuarine and coastal seawater. The method is based on differential pulse anodic stripping voltammetry (DPASV) at a rotating silver‐alloy disk electrode. The voltammetric parameters include a plating potential of ?1.5 V and an activation potential of ?5 V for 10s; the seawater is at the original sample pH. The main finding is the presence of a peak for low nmol L^?1 levels of iron at ?0.55 V ascribed to elemental iron deposited on the bare silver alloy electrode. The peak increased linearly with the iron concentration between <1 and 14 nmol L^?1 using a 900 s plating time. At higher concentrations an additional iron peak appeared at ?0.7 V which was also found to increase linearly with the iron concentration but at a higher concentration range from ca. 15 to 90 nmol L^?1 using a 300 s plating time. The second peak was ascribed to iron deposited on iron. Additions of chelating agents (EDTA and a siderophore) to seawater caused the iron peak to be masked indicating that this method is suitable for iron speciation as only the electrochemically labile fraction is determined. The detection limit was 0.3 nmol L^?1 using a 900 s plating time. The method was used to determine iron in the range of 5 to 50 nmol L^?1 in samples from the Mersey estuary near Liverpool and its potential use for in situ monitoring was demonstrated by using it to monitor labile iron (at 2–3 nmol L^?1) over a period of 4 days at 1 h intervals in coastal waters in the Trondheim fjord, Norway.     

Fitting complex potential energy surfaces to simple model potentials: application of the simplex-annealing method

A stochastic method of optimization, which combines simulated annealing with simplex, is implemented to fit the parameters of a simple model potential. The main characteristic of the method is that it explores the whole space of the parameters of the model potential, and therefore it is very efficient in locating the global minimum of the cost function, in addition to being independent of the initial guess of the parameters. The method is employed to fit the complex intermolecular potential energy surface of the dimer of water, using as a reference the spectroscopic quality anisotropic site-site potential of Feller et al. The simple model potential chosen for its reparameterization is the MCY model potential of Clementi et al. The quality of the fit is assessed by comparing the geometry of the minimum, the harmonic frequencies, and the second virial coefficients of the parameterized potential with the reference one. Finally, to prove more rigorously the robustness of this method, it is compared with standard nonstochastic methods of optimization.     

有机溶剂性质及其水含量对酶催化合成含D－氨基酸残基的二肽衍生物的影响

有机溶剂性质及其水含量对酶催化合成保护的寡肽及其衍生物有显著影响。系 统地研究了有机溶剂性质及在不同有机溶剂中水含量对α－胰凝乳蛋白酶催化合成 含D－氨基酸残基的二肽衍生物产率的影响。用α－胰凝乳蛋白酶、枯草杆菌蛋白 酶和嗜热杆菌蛋白酶在有机溶剂中催化合成了一系列保护的二肽及其衍生物，并研 究了水含量对反应产率的影响，得到了十分有意义的结果。     

The preparation of a cabbage reference material for environmental monitoring and food analysis

 Cabbage is frequently used in environmental monitoring and food control, and, hence, cabbage reference materials (RMs) are required for ensuring quality assurance. A cabbage RM was prepared in view of certification of specific elements from the "black list" of high toxicological interest and nutritive importance. All tasks of the RM production (production of the plant material, cutting and freeze-drying, determination of the residual water content, preparation of the RM, homogeneity testing, stability testing, certification measurements) are described in detail. Received: 12 November 1999 / Accepted: 29 January 2000