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Effect of background electrolytes on the adsorption of nitroaromatic compounds onto bentonite

Journal of Environmental sciences 2009年第8期21卷 1044-1052页

作者： CHEN Baoliang, HUANG Wenhai department of Environmental science, Zhejiang University, Hangzhou 310028, Zhejiang, China. department of Environmental science Zhejiang University Hangzhou 310028 Zhejiang China

To further elucidate interaction of nitroaromatic compounds with mineral surface, the sorption of m-dinitrobenzene （m-DNB） and nitrobenzene to original bentonite in aqueous solution containing different electrolytes （i.e., KCl, NH4Cl, CaCl2 and Tetramethylammonium bromide （TMAB）） was studied. The sorption of m-DNB was greatly enhanced with the presence of KCl and NH4Cl, while little influence was observed with CaCl2 and TMAB, following the order of KCl 〉 NH4Cl 〉〉 TMAB, CaCl2, or DI water. For nitrobenzene, sorption enhancement only occurred at high nitrobenzene concentrations in the presence of KCl, and the solute equilibrium concentration at inflexion point was lowered with increasing KCl concentration. These sorption enhancements were significantly promoted with the increase of electrolyte concentration. The salting-out effect is insufficient to account for the sorption enhancement by original bentonite with increasing KCI or NH4Cl concentration. X-ray diffraction patterns of bentonite suspensions indicated that the sorption enhancement of m-DNB was attributed to the intercalation of K^＋ or NH4^＋ into bentonite interlayer and then dehydration with m-DNB to form inner-sphere complexes, which caused previously expanded bentonite interlayers to collapse in aqueous suspension, thus further enhanced the interaction of phenyl with siloxane surface. In comparison, the sorption enhancement of NB is attributed to the formation of outer-sphere complexes with K^＋ at high solute-loadings （〉 20（0-400 mg/kg）. The sorption of m-DNB to initially modified TMA^＋-bentonite and K^＋-bentonite was almost the same as respective sorption to original bentonite in solution containing TMA^＋ and K^＋.

关键词： sorption nitroaromatic compound bentonite cation type wastewater treatment

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PROPERTIES AND SYNTHESIS OF NEW SUPPORTS FOR IMMOBILIZATION OF ENZYMES BY COPOLYMERIZATION OF VINYLENE CARBONATE AND METHACRYLIC ACID

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Chinese Journal of Polymer science 2000年第4期18卷 343-349页

作者： Lun-han Ding Yue Li Yan Jiang Zhe Cao Jia-xian Huang department of Polymer science and Engineering, University of science and Technology of China, Hefei 230026, China department of Chemistry, Nankai University, Tianjin 300071, China 中国科学技术大学安徽合肥南开大学天津

Methacrylic acid first was neutralized with an aqueous solution of NaOH to pH = 6.0 similar to 7.0, vinylene carbonate (VCA) was added to the solution, then monomers were copolymerized in paraffin oil by means of reverse-phase suspension polymerization and hydrophilic copolymeric supports were prepared. The properties of the supports were determined using trypsin and results show that the amount of enzymes coupled to the supports and the specific activity of immobilized trypsin are related to the content of VCA structure units, reaction time and concentration of enzyme solution, etc.

关键词： vinylene carbonate methacrylic acid fixed enzyme support trypsin

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SUPERCONVERGENCES OF THE ADINI'S ELEMENT FORSECOND ORDER EQUATION

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Journal of Computational Mathematics 1999年第6期17卷 569-574页

作者： Ping Luo(department of Computer science and Technology, Qinghua University, Beijing 100084,China)Qun Lin(Institute of Systems science, Academia Sinica, Beijing, 100080, China) 清华大学计算机系北京 100084 中科院系统科学所北京 100080

n this papers the asymptotic error expansions of Adini's element for the secondorder imhomogeneous Neumann problem are given and the superconvergence estimations are obtained. Moreover, a numerical example to support ... 详细信息

关键词： Adini's element Superconvergence estimation Asymptotic expansion.

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INFLUENCES OF ANISOTROPY ON BAND GAPS OF 2D PHONONIC CRYSTAL

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Acta Mechanica Solida Sinica 2010年第2期23卷 181-188页

作者： Zhengqiang Zhan Peijun Wei 1(department of Mathematics and Mechanics,School of Applied science,University of science and Technology Beijing,Beijing 100083,China) department of Mathematics and Mechanics School of Applied Science University of Science and Technology Beijing Beijing China

Band gaps of 2D phononic crystal with orthotropic cylindrical fillers embedded in the isotropic host are studied in this paper. Two kinds of periodic structures, namely, the square lattice and the triangle lattice, are considered. For anisotropic phononic crystal, band gaps not only depend on the periodic lattice but also the angle between the symmetry axis of orthotropic material and that of the periodic structure. Rotating these cylindrical fillers makes the angle changing continuously; as a result, pass bands and forbidden bands of the phononic crystal are changed. The plane wave expansion method is used to reduce the band gap problem to an eigenvalue problem. The numerical example is given for YBCO/Epoxy composites. The location and the width of band gaps are estimated for different rotating angles. The influence of anisotropy on band gaps is discussed based on numerical results.

关键词： phononic crystal orthotropy band gap periodicity plane wave expansion

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Design of policy mechanism to promote cleaner production in China

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Journal of Environmental sciences 2001年第3期13卷 346-350页

作者： ZHANG Tian zhu(department of Environmental science and Engineering, Tsinghua University, Beijing 100084, China. 清华大学北京 100084

In order to promote cleaner production in China, a package of policy options was presented based on the identification of the barriers encountered in the CP demonstration project and the effectiveness and feasibility of policy options for the CP implementation were analyzed. Furthermore, the policy mechanism framework was given, which composes of compulsory, economic incentive, social pressure and supportive function. Finally, the implementation strategy of the policy mechanism, in which the emphasis will be changed from compulsory policy options towards economic and social pressure policy options, was proposed.

关键词： cleaner production barrier identification policy mechanism China

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ON THE FILTRATION OF NON-NEWTONIAN FLUID IN POROUS MEDIA WITH A MULTIPLE PARAMETER MODEL

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Journal of Hydrodynamics 2001年第1期13卷 39-46页

作者： Zhu Zuo-jin department of Thermal science and Energy Engineering. University of science and Technology of China, Hefei 230026, China[WT5”HZ] Dep. of Thermal Sci. Univ. of Sci. and Technol. of China Hefei 230026 China

A multiple parameter model to describe the Non-Newtonian properties of fluid filtration in porous media is presented with regard to the pressure gradient expression in terms of the velocity of filtration, where the multiple parameters should be determined by measurements. Based on such a model, an analysis was furnished to deduce the formula for the rate of production of an oil well, and the governing equations for single phase Non-Newtonian fluid filtration. In order to examine the effects of model parameters, the governing equations were numerically solved with the method of cross-diagonal decomposition ZG method. It is found that, for constant rate of production, the power index n of the model influences the pressure distribution considerably, particularly in the vicinity of a single well. The well-bore pressure of Leibenzonian fluid is lower than that of the power-law fluid in the case of the same parameter B and the power index n=0.5.

关键词： Computer simulation Mathematical models Non Newtonian liquids Oil well production

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Simulation of the diffusion process in composite porous media by random walks

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Progress in Natural science:Materials International 2005年第12期15卷 1117-1125页

作者： ZHANG Yong department of Hydrologic science,Desert Research Institute,Reno,NV 89512,USA department of Hydrologic science Desert Research Institute Reno NV 89512 United States

A new random-walk interpolation scheme was developed to simulate solute transport through composite porous media with different porosities as well as different *** significant influences of the abrupt variations of porosity and diffusivity on solute transport were simulated by tracking random walkers through a linear interpolation domain across the heterogeneity *** displacements of the random walkers within the interpolation region were obtained explicitly by establishing the equivalence between the Fokker-Planck equation and the advection-dispersion *** indicate that the random-walk interpolation method can simulate one- and two-dimensional,2nd-order diffusion processes in composite media without local mass conservation *** addition,both the theoretical derivations and the numerical simulations show that the drift and dispersion of particles depend on the type of Markov process selected to reflect the dynamics of random *** the nonlinear Langevin equation is used,the gradient of porosity and the gradient of diffusivity strongly affect the drift displacement of ***,random-walking particles driven by the gradient of porosity, the gradient of diffusivity,and the random diffusion,can imitate the transport of solute under only pure diffusion in composite porous media containing abrupt variations of porosity and diffusivity.

关键词： random-walk diffusion process composite porous media solute transport

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SOME THERMODYNAMIC PROPERTIES OF Pd-In ALLOYS

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Acta Metallurgica Sinica(English Letters) 1997年第4期10卷 311-317页

作者： YL. Chen(department of Materials science and Engineering, Zhejiang University, Hangzhou 310027, China) Zhejiang Univ Hangzhou China

Some thermodynamic parnmeters of Pd-In alloys with 2 to 70 at. H indium have been determined in the temperuture range 800 to 1000℃ from e.m.f measurements ongalvanic cells with an onsen-cotzducting solid electrolyte. Heats of tnising calculated hem the activities are in excellent agreement with calorimetric data. The relative partial excess hee enengy of indiurn assumes unnsually larpe negative values ap to-174kJ/mol for Pd-rich alloys. Two efficts are discussed to account for the non-idealproperties: The rise Of Fermi enerpy as the valence electron8 of indium enter the 4dand 5sP bands of the alloy and the lattice distortion brought about by the differentmolar volumes of the cofnponents. The rise of the Fermi enerpy, as determlned fromthe activity data, indicates a strict adherence of the alloys to the rigid band model.

关键词： galvanic cell activity data Fermi energy,lattice distortion rigid band model

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Phase Separation and Theta-compositions of PPES/NMP/non-solvent Systems

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Journal of Materials science & Technology 2005年第3期21卷 430-432页

作者： Yi SU and Xigao JIAN department of Polymer science, Dalian University of Technology, Dalian 116012, China department of Polymer science Dalian University of Technology Dalian 116012 China

Poly (phthalazinone ether sulfone) (PPES) with 1:1 and 1:3 ratios of bisphenol A (BPA) unit to phthalazinone unit were selected as samples. Polymer precipitation curves for the ternary systems PPES (1:1)/NMP/ non-solvent and PPES (1:3)/NMP/non-solvent were determined by a titration method. Comparison between two sets of data is made. Non-solvents used were H2O, ethyl ether (EE), diethylene glycol (DEGC), ethyleneglycol methylether (EGME) and butanone (BO). NMP/non-solvent theta-compositions for PPES (1:1) and PPES (1:3) were also estimated. It was found that the volume ratio of non-solvent to NMP at the property mutation or worsening of PPES membrane is close to the theta-composition.

关键词： Polymer precipitation curve Poly (phthalazinone ether sulfone) Theta-composition

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Glacial-Interglacial Atmospheric CO_2 Change——The Glacial Burial Hypothesis

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Advances in Atmospheric sciences 2003年第5期20卷 677-693页

作者： Ning ZENG department of Meteorology and Earth System science Interdisciplinary Center, University of Maryland, USA department of Meteorology and Earth System science Interdisciplinary Center University of Maryland USA

Organic carbon buried under the great ice sheets of the Northern Hemisphere is suggested to be the missing link in the atmospheric CO2 change over the glacial-interglacial cycles. At glaciation, the advancement of continental ice sheets buries vegetation and soil carbon accumulated during warmer periods. At deglaciation, this burial carbon is released back into the atmosphere. In a simulation over two glacial-interglacial cycles using a synchronously coupled atmosphere-land-ocean carbon model forced by reconstructed climate change, it is found that there is a 547-Gt terrestrial carbon release from glacial maximum to interglacial, resulting in a 60-Gt (about 30-ppmv) increase in the atmospheric CO2, with the remainder absorbed by the ocean in a scenario in which ocean acts as a passive buffer. This is in contrast to previous estimates of a land uptake at deglaciation. This carbon source originates from glacial burial, continental shelf, and other land areas in response to changes in ice cover, sea level, and climate. The input of light isotope enriched terrestrial carbon causes atmospheric δ13C to drop by about 0.3‰ at deglaciation, followed by a rapid rise towards a high interglacial value in response to oceanic warming and regrowth on land. Together with other ocean based mechanisms such as change in ocean temperature, the glacial burial hypothesis may offer a full explanation of the observed 80–100-ppmv atmospheric CO2 change.

关键词： atmospheric CO2 ice age glacial burial hypothesis climate

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