检索结果-南通市图书馆

ON MULTIPLE POSITIVE SOLUTIONS FOR A NONLINEAR ELLIPTIC PROBLEM IN R^N

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 2000年第3期21卷 351-358页

作者： YANG HAITAO(department of mathematics, zhejiang university, hangzhou 310027, china.) wu SHAOPING(department of mathematics, zhejiang university, hangzhou 310027, china.) department of mathematics Zhejiang University Hangzhou 310027 China

By making use of Variational method, the authors obtain some results about existence of multiple positive solutions and their asymptotic behavior as the parameter →＋∞ for a semilinear elliptic problem in RN.

关键词： Critical point Asymptotic behavior Concentration

On Holomorphic Automorphisms of a Class of Non-homogeneous Rigid Hypersurfaces in C^(N+1)

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 2010年第2期31卷 201-210页

作者： Qingyan wu department of mathematics,Linyi Normal university,Linyi 276005,Shandong,china department of mathematics,zhejiang university,hangzhou 310027,china department of mathematics Linyi Normal University Linyi China department of mathematics Zhejiang University Hangzhou China

The author determines the real-analytic infinitesimal CR automorphisms of a class of non-homogeneous rigid hypersurfaces in CN+1 near the origin,and the connected component containing the identity transformation of al... 详细信息

关键词： Real-analytic infinitesimal CR automorphisms Rigid hypersurfaces Holomorphic automorphisms

Rotationally symmetric translating soliton of H^k-flow

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2010年第4期53卷 1011-1016页

作者： SHENG WeiMin & wu Chao department of mathematics,zhejiang university,hangzhou 310027,china department of mathematics Zhejiang University Hangzhou China

This paper mainly considers the translating soliton of H k-flow for k > *** give the asymptotic expression of the entire rotationally symmetric translating soliton,and obtain non-convex 'Wing-like' solution as well as... 详细信息

关键词： H k-flow translating soliton 'Wing-like' solution

Preparation and characterization of bis(dimolybdo-nonatungstogermanate)lanthanates of potassium

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2003年第1期22卷 6-9页

作者： wu Qingyindepartment of Chemistry, zhejiang university, hangzhou 310027, china department of Chemistry Zhejiang University Hangzhou 310027 China

The heteropoly complexes K_(13)[Ln(GeW_9Mo_2O_(39))_2] centre dot nH_2O (Ln =La, Ce, Pr, Nd, and Sm) were prepared for the first time and characterized by chemical analysis,infrared (IR) spectrum, ultraviolet (UV) spectrum, X-ray powder diffraction, and thermal ***, UV spectra, and X-ray powder diffraction studies show that the structure of the heteropolycomplexes is a square antiprism consisting of eight oxygen atoms of two GeW_9Mo_2O_(39)^(8-)heteropolyanions and a lanthanide ion. The thermostability of heteropoly complexes is lower thanthat of saturated Keggin structure dodecatungstogermanate.

关键词： inorganic chemistry heteropoly complex chemical synthesis lanthanates germanium

Preparation and Conductivity of Triheteropoly Tungstozincoaluminic Acid

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2001年第4期20卷 221-223页

作者： Qingyin wu department of Chemistry, zhejiang university, hangzhou 310027, china 浙江大学浙江杭州 310027

The ternary undecatungstozincoaluminic heteropoly acid H-7[Al(H2O)ZnW11O39](.)12H(2)O was prepared by the ion exchanging-cooling method. The optimal proportion of solutions of the component elements and the pH of the synthesis reaction were given. The product was characterized by chemical analysis, potentiometric titration, IR, UV, XRD and TG-DTA. AC impedance measurement results show that its proton conductivity is 1.37x10(-4) S/cm at 18 degreesC.

关键词： heteropoly acid tungstozincoaluminic acid protonic conductivity

POLYMERIZATION OF γ-STEARYL-α,l-GLUTAMATE N-CARBOXYANHYDRIDE USING RARE EARTH COORDINATION CATALYSTS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2000年第4期18卷 369-372页

作者： Xiao-ping Hu Jian wu Zhi-kang Xu Lin-xian Feng Institute of Polymer Science, zhejiang university, hangzhou 310027, china department of Chemistry, zhejiang university, hangzhou 310027, china 浙江大学浙江杭州

A rare earth coordination system was first investigated as a new type of catalyst for the ring-openingpolymerization of α-amino acid N-carboxyanhydrides (NCAs). The results for the polymerization of γ-stearyl-α,L-glutamate(SLG) NCA using neodymium acetylacetonate (Nd(acac)_3)- or neodymium tris(2-ethylhexylphosphonate) (Nd(P_(204))_3)-triethylaluminum-water as catalysts were compared with those using conventional catalysts. It was found that the helicalpoly(γ-stearyl-L-glutamate) with high molecular weight as well as narrow molecular weight distribution can be obtained inthe presence of Nd(acac)_3/AlEt_3-1/2H_2O. The polymer obtained was characterized by IR and NMR spectroscopy.

关键词： Rare earth coordination catalyst Ring-opening polymerization Polypeptide Poly(γ-stearyl-α,L-glutamate)

CHEMOENZYMATIC SYNTHESIS OF BIODEGRADABLE POLY(1’-O-VINYLADIPOYL-SUCROSE)

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2002年第6期20卷 579-584页

作者： De-shui Lu Qi wu Xian-fu Lin department of Chemistry zhejiang university hangzhou 310027, china department of Chemistry Zhejiang University Hangzhou 310027

A novel polymer containing the sucrose group was synthesized by radical polymerization from an enzymatically prepared monomer, 1'-O-vinyladipoyl-sucrose (VAS). Transesterification reaction of sucrose with divinyl adipate in anhydrous pyridine catalyzed by an alkaline protease from Bacillus subtilis at 60degreesC for 7 days gave VAS (yield 55%) without any blocking/deblocking steps. The vinyl sucrose ester could be polymerized with potassium persulfate and H2O2 as initiator to give poly(1'-O-vinyladipoyl-sucrose) with M-n = 33,000 and M-w = 53,200, M-w/M-n = 1.61. The polymer was biodegradable. After 6 days in aqueous buffer (pH 7), this alkaline protease could degrade poly(1'-O-vinyladipoyl-sucrose) to M. of ca. 1080, M-w/M-n = 3.30 (37degreesC), and M-n of ca. 5200, M-w/M-n = 2.44 (4degreesC). The polymer containing the sucrose branch would be a functional material in various application fields.

关键词： divinyladipate sucrose alkaline protease polymerization biodegradation

A HOMOCLINIC ORBIT FOR LAGRANGIAN SYSTEMS

在线全文

学校读者我要写书评

暂无评论

Systems Science and Mathematical Sciences 1995年第1期8卷 75-81页

作者： wu Shaoping (department of mathematics, zhejiang university, hangzhou 310027, china) 浙江大学数学系浙江杭州

ＡＨＯＭＯＣＬＩＮＩＣＯＲＢＩＴＦＯＲＬＡＧＲＡＮＧＩＡＮＳＹＳＴＥＭＳＷＵＳｈａｏｐｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ，Ｈａｎｇｚｈｏｕ３１００２７，Ｃｈｉ... 详细信息

ＡＨＯＭＯＣＬＩＮＩＣＯＲＢＩＴＦＯＲＬＡＧＲＡＮＧＩＡＮＳＹＳＴＥＭＳＷＵＳｈａｏｐｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ，Ｈａｎｇｚｈｏｕ３１００２７，Ｃｈｉｎａ）Ａｂｓｔｒａｃｔ：Ｗｅｐｒｏ...

关键词： Homoclinic orbit Lagrangian system Mountain Pass Lemma.

Immobilized chitosan as a selective absorbent for the nickel removal in water sample

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2003年第5期15卷 633-638页

作者： wu Jian min, WANG Yong yao (department of Chemistry, College of Science, zhejiang university, hangzhou 310027, china. ) department of Chemistry College of Science Zhejiang University Hangzhou 310027 Chin

Method for preparation of chitosan immobilized on silica gel(CTS silica) was described. The CTS silica was used as absorbent for the absorption of nickel in water. The results showed that this absorbent had relatively high selectivity and strong affinity to nickel. The maximum absorption capacity for nickel can reach 667 mg/g of chitosan. Factors that affect the absorption capacity, such as pH, ion strength and the presence of calcium, EDTA and the mechanism of absorption were discussed in detail. The absorbent can be regenerated with acid and reused for several times. The recovery rate for nickel can reach 99 99%. This absorbent filled in a column can be used in nickel removal from wastewater and drinking water.

关键词： immobilized chitosan nickel wastewater treatment