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The Existence Theorems for a Class of Sublinear Elliptic Equations in R^N

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Acta Mathematica Sinica,English Series 1997年第3期13卷 295-304页

作者： wu Shaoping Yang Haitao (department of mathematics,zhejiang university,hangzhou 310027,china)

An existence theorem for the solution to the equation -△u+b(x)u=f(x,u),in R^N is given by means of variational method where b(x)→∞,as丨x丨→∞ and f(x,s)has linear growth in s at infinity and sublinear growth in s ... 详细信息

关键词： Sublinear elliptic equation Critical point theory Compactness

MECHANISM OF DEUTERIUM CRACKING IN PALLADIUM

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Acta Metallurgica Sinica(English Letters) 1993年第2期6卷 136-139页

作者： SUN Dalin LEI Yongquan CHEN Yanglin wu Jing WANG Qidong zhejiang university,hangzhou,china department of Materials Science and Engineering,zhejiang university,hangzhou 310027,china zhejiang Univ Hangzhou China

After 290 h electrochemical charging of deuterium,the density of dislocation in well-annealed Pd was increased from 10~8/cm^2 to over 10~12/cm^2 and a large amount of bubble-like voids or cracks was observed by optical and transmission electron *** mechanism of deuterium cracking is believed due to the formation of molecular De during the segregstion and combination of deuterium atoms around *** results showed that the lattice constant of Pd increased from 0.3890 nm to 0.4034 nm.

关键词： deuterium cracking Pd

Goodness-of-fit tests for vector autoregressive models in time series

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Science china mathematics 2010年第7期53卷 187-202页

作者： wu JianHong 1,& ZHU LiXing 21 College of Statistics and mathematics,zhejiang Gongshang university,hangzhou 310018,china 2 department of mathematics,Hong Kong Baptist university,Hong Kong,china College of Statistics and mathematics Zhejiang Gongshang University Hangzhou China department of mathematics Hong Kong Baptist University Hong Kong China

The paper proposes and studies some diagnostic tools for checking the goodness-of-fit of general parametric vector autoregressive models in time series. The resulted tests are asymptotically chi-squared under the null hypothesis and can detect the alternatives converging to the null at a parametric rate. The tests involve weight functions,which provides us with the flexibility to choose scores for enhancing power performance,especially under directional alternatives. When the alternatives are not directional,we construct asymptotically distribution-free maximin tests for a large class of alternatives. A possibility to construct score-based omnibus tests is discussed when the alternative is saturated. The power performance is also investigated. In addition,when the sample size is small,a nonparametric Monte Carlo test approach for dependent data is proposed to improve the performance of the tests. The algorithm is easy to implement. Simulation studies and real applications are carried out for illustration.

关键词： goodness-of-fit test maximin test nonparametric Monte Carlo test score type test time series vector autoregressive model

ON INDEFINITE SUBLINEAR ELLIPTIC EQUATIONS

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Systems Science and Mathematical Sciences 2000年第1期13卷 48-58页

作者： YANG Hai tao wu Shao ping (department of mathematics, zhejiang university, hangzhou 310027, china) 浙江大学数学系浙江杭州 310027 浙江大学数学系浙江杭州

***,N23,beasmoothboundeddomainandconsiderthesemilinearellipticequationswhereatbELoc(Q),***eaction-diffusionprocessess(seethereferencesof[1]).Bytheresultsof[... 详细信息

***,N23,beasmoothboundeddomainandconsiderthesemilinearellipticequationswhereatbELoc(Q),***eaction-diffusionprocessess(seethereferencesof[1]).Bytheresultsof[...

关键词： Sublinear elliptic equation critical point theory sub-sup-solution.

MEMS-actuated terahertz metamaterials driven by phase-transition materials

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Frontiers of Optoelectronics 2024年第2期17卷 23-32页

作者： zhixiang Huang Weipeng wu Eric Herrmann Ke Ma Zizwe A.Chase Thomas A.Searles M.Benjamin Jungfleisch Xi Wang department of Materials Science and Engineering College of EngineeringUniversity of DelawareNewarkDE 19716USA department of Physics and Astronomy College of Arts and SciencesUniversity of DelawareNewarkDE 19716USA department of Electrical and Computer Engineering College of EngineeringUniversity of Illinois ChicagoChicagoIL 60607USA

The non-ionizing and penetrative characteristics of terahertz(THz)radiation have recently led to its adoption across a variety of *** effectively utilize THz radiation,modulators with precise control are *** most recent THz modulators manipulate the amplitude,frequency,or phase of incident THz radiation,considerably less progress has been made toward THz polarization *** methods for polarization control suffer from high driving voltages,restricted modulation depth,and narrow band capabilities,which hinder device performance and broader ***,an ideal THz modulator that offers high modulation depth along with ease of processing and operation is *** this paper,we propose and realize a THz metamaterial comprised of microelectromechanical systems(MEMS)actuated by the phase-transition material vanadium dioxide(VO_(2)).Simulation and experimental results of the three-dimensional metamaterials show that by leveraging the unique phase-transition attributes of VO_(2),our THz polarization modulator offers notable advancements over existing designs,including broad operation spectrum,high modulation depth,ease of fabrication,ease of operation condition,and continuous modulation *** enhanced features make the system a viable candidate for a range of THz applications,including telecommunications,imaging,and radar systems.

关键词： Metamaterials MEMS THz VO_(2) Phase-transition material

Preliminary studies on the chemical characterization and antioxidant properties of acidic polysaccharides from Sargassum fusiforme

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Journal of zhejiang university-Science B(Biomedicine & Biotechnology) 2008年第9期9卷 721-727页

作者： Jing ZHOU, Nan HU, Ya-lin wu, Yuan-jiang PAN, Cui-rong SUN (department of Chemistry, zhejiang university, hangzhou 310027, china) department of Chemistry Zhejiang University Hangzhou 310027 China.

In order to investigate the antioxidant properties of the polysaccharides from the brown alga Sargassum fusiforme, the crude polysaccharides from S. fusiforme (SFPS) were extracted in hot water, and the lipid peroxidation inhibition assay exhibited that SFPS possessed a potential antioxidant activity. Hence, two purely polymeric fractions, SFPS-1 and SFPS-2 were isolated by the column of DEAE (2-diethylaminoethanol)-Sepharose Fast Flow, with their molecular weights of 51.4 and 30.3 kDa determined by high performance gel permeation chromatography (HPGPC). They were preliminarily characterized using chemical analysis in combination of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies and found to contain large amounts of uronic acids and β-glycosidical linkages. The antioxidant activities of these two SFPS fractions were evaluated using superoxide and hydroxyl radical-scavenging assays. The results show that the antioxidant ability of SFPS-2 was higher than that of SFPS-1, probably correlating with the molecular weight and uronic acid content.

关键词： Sargassum fusiforme Polysaccharide Antioxidant activity Uronic acid Molecular weight

THE ELECTROCHEMICAL PERFORMANCES OF Zr-BASED HYDROGEN STORAGE ALLOYS

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中国有色金属学会会刊：英文版 1995年第3期5卷 61-65页

作者： Yang, Xiaoguang Lei, Yongquan wu, Jing Wang, Qidong(department of Materials Science and Engineering, zhejiang university, hangzhou 310027) zhejiang Univ Hangzhou China

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ＴＨＥＥＬＥＣＴＲＯＣＨＥＭＩＣＡＬＰＥＲＦＯＲＭＡＮＣＥＳＯＦＺｒ－ＢＡＳＥＤＨＹＤＲＯＧＥＮＳＴＯＲＡＧＥＡＬＬＯＹＳ￥Ｙａｎｇ，Ｘｉａｏｇｕａｎｇ；Ｌｅｉ，Ｙｏｎｇｑｕａｎ；Ｗｕ，Ｊｉｎｇ；Ｗａｎｇ，Ｑｉｄｏｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔ...

关键词： Zr-based Laves phase crystal structure electrode performances

One-step Synthesis of n-Butanol from Ethanol Condensation over Alumina-supported Metal Catalysts

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Chinese Chemical Letters 2004年第12期15卷 1497-1500页

作者： Ke wu YANG Xuan Zhen JIANG Wei Chao ZHANGD department of Chemistry, zhejiang university, hangzhou 310027 department of Chemistry Zhejiang University Hangzhou 310027 China

One-step synthesis of n-butanol from bimolecular condensation of ethanol was firstlyachieved over nickel supported gamma alumina catalyst. A mechanism of dehydration path for thegrowth of carbon chain by eliminating a hydroxy group from one ethanol molecule with a α-H ofother ethanol molecule rather than aldol condensation was verified.

关键词： Ethanol condensation n-butanol nickel supported on gamma alumina dehydration

BIFURCATIONS FROM HOMOCLINIC ORBITS FOR SECOND ORDER HAMILTONIAN SYSTEM

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Systems Science and Mathematical Sciences 1998年第1期11卷 47-52页

作者： wu Shaoping YANG Haitao(department of mathematics, zhejiang university, Hangchou 310027, china)

An existence theorem of homoclinic orbit is given for second order Hamiltoniansystem-x(t) + a(t)x(t) - Wx(t, x(t)) = x(t)when = 1, where 1 is the first eigenvalue of operator Lx = x - a(t)x, and Wx(t, x) issublinear growth in x Rn. When Wx(t, x) is odd in x,. infinitely many distinct pairs ofhomoclinic orbits are obtained and the bifurcations occur for each 1.

关键词： Bifurcations homoclinic orbit Hamiltonian system variational method.