Hongwei Yang

Tsinghua University, Beijing, Beijing Shi, China

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Publications (7)11.88 Total impact

  • Journal of Raman Spectroscopy 09/2009; 40(9):1200-1204. · 2.68 Impact Factor
  • Hongwei Yang, Zhanpeng Jiang, Shaoqi Shi
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    ABSTRACT: Anaerobic biodegradability of 46 kinds of aromatic compounds was tested and assessed in integrate. These aromatic compounds were classified into readily, partially and poorly biodegradable compounds after their integrated assessment indices (IAI) were calculated. Some rules of anaerobic biodegradation of them were drawn. Stepwise regression and backpropagation artificial neural network (BP-ANN) methods were applied to establish quantitative structure biodegradability relationship (QSBR) based on the assessment results. In QSBR models, five molecular structure descriptors, energy of the highest occupied molecular orbital (EHOMO), total energy (TolE), molar refractivity (MR), the logarithm of the partition coefficient for n-octanol/water (LogP), and standard Gibbs free energy (G), were included. After analyzing the sensitivity of variables in QSBR models, it was found that the key molecular structure descriptors affecting anaerobic biodegradability of aromatic compounds were TolE and MR, which were in direct proportion to the anaerobic biodegradability of aromatic compounds.
    Science of The Total Environment 05/2006; 358(1-3):265-76. · 3.26 Impact Factor
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    ABSTRACT: Effects of temperature and some aqueous solutions of electrolytes consisting of ions in natural water on the chemical shifts of NMR of water (17O NMR) have been measured. Combining the cluster model of liquid water structure and the dependence of δ(17OH2) on temperature a relationship deduced of δ(17OH2) to median water cluster size effects of ions on median water cluster and the size are analyzed. The relationships between 17O NMR and concentration of ions are linear. Cations increase the median water cluster size and anions decrease it. The bigger the radius of ions with equal ionic charge, the stronger the effect of the ion. The extent of the ionic charge effect is much bigger than that of the ionic radius. The order of the effect of cations and anions is Na+
    Journal of Molecular Liquids - J MOL LIQ. 01/2006; 126(1):14-18.
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    ABSTRACT: The OH stretching (2500–4000 cm−1) Raman spectra from pure water and sodium halides solutions are obtained. The Raman contours are deconvoluted with five Gaussian components that their center frequencies are 3051, 3233, 3393, 3511 and 3628 cm−1, respectively. From the Raman spectra and their deconvolutions similarities and differences of the effects of temperature and sodium halides on hydrogen bond structure of water are shown clearly. Like temperature, all of sodium halides break tetrahedral structure of water, and the Gaussian component of 3233 cm−1 decreases and the components of 3393 and 3511 cm−1 increase basically. The differences lie in their effects on the component 3051 and 3628 cm−1. All of halogenic ions break tetrahedral structure of water and their breaking actions are in the order of F−1<Cl−1<Br−1<I−1. The reason is relative to the strength of halogenic ion–water and water–water hydrogen bonds.
    Journal of Molecular Structure 01/2004; 707:83-88. · 1.40 Impact Factor
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    ABSTRACT: With various concentrations of CaCl 2 and MgCl 2 aqueous solution below 1.0 mol/l, Raman spectra of water in the OH stretch region of 2500-4000 cm -1 and 17O NMR chemical shift of water are measured and the Raman spectra are deconvoluted. Both Raman spectra and 17O NMR of water show that the effect of Ca 2+ on water structure is stronger than that of Mg 2+. CaCl 2 and MgCl 2 destroy four hydrogen bonded water structure, but promote median water cluster size.
    Journal of Molecular Structure 01/2003; 645(1):69-75. · 1.40 Impact Factor
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    ABSTRACT: In this paper, the amount of oxygen consumption, end products and activities of microorganisms are considered as the three factors which affect the biodegradability of organic substances in water. Two integrated assessment methods for biodegradability of organic substances, fuzzy clustering integrated assessment and weighted integrated assessment, have been developed. Simultaneously, the detail steps for assessing a new organic substance biodegradability with these two integrated assessment methods are proposed.
    Chemosphere 08/2002; 48(1):133-8. · 3.14 Impact Factor
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    ABSTRACT: There are various kinds of trace ions in water supply, such as Na+, K+, Ca2+, Mg2+ and Cl-, SO(4)2-, CO(3)2- etc. 17O-NMR chemical shift and line-width of water were measured under different temperature and different concentrations of various salts in aqueous solutions containing those ions. The relationship of 17O-NMR chemical shift and line-width of water to water association and the effect of ions on water association were analyzed. Cations promoted water association and anions destroyed water association. Generally, the more the ionic charge and the larger the ionic radius, the larger was the effect of those ions on water association. Besides, the effect of ionic charge on water association was more significant than that of ionic radius.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 06/2002; 23(3):44-8.

Publication Stats

24 Citations
142 Views
11.88 Total Impact Points

Institutions

  • 2003–2006
    • Tsinghua University
      • • School of Environment
      • • Department of Environmental Engineering
      Beijing, Beijing Shi, China