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Studies on the structure and catalytic performance of S and P promoted Na-W-Mn-Zr/SiO_2.catalyst for oxidative coupling of methane

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Journal of Natural Gas Chemistry 2010年第1期19卷 15-20页

作者： Wen Zheng, Dangguo Cheng, Ning Zhu, Fengqiu Chen, Xiaoli Zhan department of Chemical and Biochemical engineering,{2., hangzhou 310027, zhejiang, china [a] department of Chemical and Biochemical engineering Zhejiang University Hangzhou 310027 Zhejiang China

A series of Na-W-Mn-Zr/SiO2.catalysts promoted by different contents of S or/and P were prepared and their catalytic performance for oxidative coupling of methane was investigated to clarify the effect of S and P on the Na-W-Mn-Zr/SiO2.catalyst. The catalysts were characterized by X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）. From the characterization results, it is found that the addition of S and P to the Na-W-Mn-ZffSiO2.catalyst helps the formation of active phases, such as α-cristobalite, Na2.O4, ZrO2. and Na2.O4. Moreover, the addition of S and P increases the concentration of surface-active oxygen species by improving the migration of active components from the bulk phase to the surface of the catalyst. According to the activity test, impressive methane conversion and C2.hydrocarbons yield were obtained at a low temperature of 102. K over the six-component Na-W-Mn-Zr-S-P/SiO2.catalyst, which contained 2.wt% S and 0.4 wt% P simultaneously. The deactivation of Na-W-Mn-Zr-S-P/SiO2.was due to the loss of surface active components.

关键词： oxidative coupling of methane Na-W-Mn-Zr/SiO2 S P

Analytical solution and semi-analytical solution for anisotropic functionally graded beam subject to arbitrary loading

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science china(Physics,Mechanics & Astronomy) 2009年第8期52卷 1244-1256页

作者： HUANG DeJin1,2.DING HaoJiang1 & CHEN WeiQiu3 1 Key Laboratory of Soft Soils and Geoenvironmental engineering,Ministry of Education,zhejiang {2.,hangzhou 310027,china 2.Faculty of engineering,Ningbo {2.,Ningbo 3152.1,china 3 department of engineering Mechanics,zhejiang {2.,hangzhou 310027,china Key Laboratory of Soft Soils and Geoenvironmental engineering Ministry of Education Zhejiang University Hangzhou 310027 China Faculty of engineering Ningbo University Ningbo 315211 China department of engineering Mechanics Zhejiang University Hangzhou 310027 China

Analytical and semi-analytical solutions are presented for anisotropic functionally graded beams subject to an arbitrary load,which can be expanded in terms of sinusoidal *** plane stress problems,the stress function is assumed to consist of two parts,one being a product of a trigonometric function of the longitudinal coordinate(x) and an undetermined function of the thickness coordinate(y),and the other a linear polynomial of x with unknown coefficients depending on *** governing equations satisfied by these y-dependent functions are *** expressions for stresses,resultant forces and displacements are then deduced,with integral constants determinable from the boundary *** the analytical solution is derived for the beam with material coefficients varying exponentially or in a power law along the thickness,the semi-analytical solution is sought by making use of the sub-layer approximation for the beam with an arbitrary variation of material parameters along the *** present analysis is applicable to beams with various boundary conditions at the two *** numerical examples are presented for validation of the theory and illustration of the effects of certain parameters.

关键词： anisotropic material functionally graded arbitrary loading stress function analytical solution semi-analytical solution

STUDY ON THE MORPHOLOGY OF POLYVINYL CHLORIDE/POLYSTYRENE BLENDS BY ELECTRON MICROPROBE ANALYSIS

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Chinese Journal of polymer science 2000年第5期18卷 437-441页

作者： Zheng-ping Fang Gen-lin Wang Guo-ping Cai Cheng-wei Xu Jie Qian Institute of polymer Composites, zhejiang university,{2., china College of Chemical engineering, zhejiang university of Technology, hangzhou 310014, china zhejiang Univ Inst Polymer Composites Hangzhou 310027 Peoples R China zhejiang Univ Technol Coll Chem Engn Hangzhou 310014 Peoples R China

The morphology of polyvinyl chloride/polystyrene (PVC/PS) blend samples with different mass ratios, prepared by means of solution casting and melt mixing, have been successfully examined by electron microprobe analysis (EMP). This experiment was performed in a scanning electron microscope attached to an energy dispersive X-ray analyzer. Differential scanning calorimetry was also used to investigate the phase separation of the blends. The results show that PVC and PS are incompatible and the blends have sea-islands phase structures. Blends prepared via melt mixing have finer phase-dispersion than those prepared via solution casting.

关键词： electron microprobe analysis polyvinyl chloride/polystyrene blends morphology

Ordinal scheduling problem and its asymptotically optimal algorithms on parallel machine system

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science in china(Series F) 2004年第2期47卷 161-169页

作者： TAN Zhiyi1,2.& HE Yong1 1. department of Mathematics, zhejiang university,{2., china (email: tanzy@math.zju. *** heyong@math.zju.***) 2. State Key Laboratory of CAD & CG, zhejiang university,{2., china 1. department of Mathematics Zhejiang University 310027 Hangzhou China 2. State Key Laboratory of CAD & CG Zhejiang University 310027 Hangzhou China

Focusing on the ordinal scheduling problem on a parallel machine system, we discuss the background of ordinal scheduling and the motivation of ordinal algorithms. In addition, for the ordinal scheduling problem on identical parallel machines with the objective to maximize the minimum machine load, we then give two asymptotically optimal algorithm classes which have worst-case ratios very close to the upper bound of the problem for any given m. These results greatly improve the results proposed by He Yong and Tan Zhiyi in 2.02.

关键词： scheduling design and analysis of algorithm worst-case ratio.

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

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

作者： CHEN Baoliang, HUANG Wenhai department of Environmental science,{2., hangzhou 31002., zhejiang, china. [a]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 （〉 2.（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

EXACT SOLUTION TO THE PROBLEM OF A HALF-PLANE CRACK IN A TRANSVERSELY ISOTROPIC PIEZOELECTRIC BODY SUBJECTED TO ANTISYMMETRIC TANGENTIAL POINT FORCES

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Acta Mechanica Solida Sinica 2001年第2期14卷 176-182页

作者： Hou Pengfei Ding Haojiang Guan Fuling (department of Civil engineering,{2., hangzhou 310027, china) ***

An exact and complete solution of the problem of a half-planecrack in an infinite transversely isotropic piezoelectric body ispresented. The upper and lower crack faces are assumed to be loadedantisym- metrically by a couple of tangential point forces inopposite directions. The solution is derived through a lim- itingprocedure from that of a penny-shaped crack. The expressions for theelectroelastic field are given in terms of elementary ***, the numerical results of the second and third mode stressintensity factors k_2.and k_3 of piezoelectric materials and elasticmaterials are compared in figures.

关键词： half-plane crack transversely isotropic piezoelectric body antisymmetrictangential forces

Dynamics and control designs for internal thermally coupled distillation columns with different purities,Part 1:Open loop dynamic behaviors

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Progress in Natural science:Materials International 2006年第5期16卷 346-351页

作者： ZHU Yu, LIU Xinggao and CHU Jian National Laboratory of Industrial Control Technology, department of Control science and {2., zhejiang university, hangzhou 310027, china [a]National Laboratory of Industrial Control Technology department of Control science and {2. Zhejiang University Hangzhou China

The open loop dynamic behaviors of internal thermally coupled distillation column with four different purities (low-, moderate-, high- and very high-purity) are studied. These dynamic behaviors are characterized by strong asymmetric non-linearity, high sensitivity to operation conditions change and distinct inverse response. With the increase of purity, these dynamic behaviors are intensified and become more complex, which easily lead to the mismatch between linear model and plant and also change the relationship between manipulated and controlled variables.

关键词： thermal coupling inverse response non-linearity high purity asymmetric behavior.

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GLOBAL EXISTENCE AND ASYMPTOTICS BEHAVIOR OF SOLUTIONS FOR A RESONANT KLEIN-GORDON SYSTEM IN TWO SPACE DIMENSIONS

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Chinese Annals of Mathematics,Series B 2005年第1期26卷 89-104页

作者： XUERUYING FANGDAOYUAN departmentofMathematics ZhejiangUniversityHangzhou310027China departmentofMathematics ZhejiangUniversityHangzhou310027China

The authors study a resonant Klein-Gordon system with convenient nonlinearities in two space dimensions, prove that such a system has global solutions for small, smooth,compactly supported Cauchy data, and find that t... 详细信息

关键词： Klein-Gordon equation Asymptotic behavior Global existence

LOCAL WELL-POSEDNESS AND ILL-POSEDNESS ON THE EQUATION OF TYPE □u= u^k(u)~α

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Chinese Annals of Mathematics,Series B 2005年第3期26卷 361-378页

作者： FANGDAOYUAN WANGCHENGBO departmentofMathematics ZhejiangUniversityHangzhou310027China

This paper undertakes a systematic treatment of the low regularity local well-posedness and ill-posedness theory in H3 and Hs for semilinear wave equations with polynomial nonlinearity in u and (?)u. This ill-posed re... 详细信息

关键词： Semilinear wave equation Low regularity Local well-posedness Ill-posedness