检索结果-南通市图书馆

Level Set interface treatment and its application in Euler method

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 227-236页

作者： WU KaiTeng1,2,HAO Li3.WANG Cheng4 & ZHANG Li1,2 1 Numerical Simulation Sichuan Higher School Key Laboratory,Neijiang Normal university,Neijiang 641112,china 2 college of Mathematics and Information {3.,Neijiang Normal university,Neijiang 641112,china 3.college of {3.,Beijing university of Civil Engineering and Architecture,Beijing 100044,china 4 State Key Laboratory of Explosion {3. and Technology,Beijing Institute of Technology,Beijing 100081,china 1. Numerical Simulation Sichuan Higher School Key Laboratory Neijiang Normal University Neijiang 641112 China2. College of Mathematics and Information Science Neijiang Normal University Neijiang 641112 China3. College of Science Beijing University of Civil Engineering and Architecture Beijing 100044 China4. State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China

Level Set interface treatment method is introduced into Euler method,which is employed for interface treatment method for multi-materials. Combined with the ghost fluid method,the moving interface is tracked. Fifth-order WENO spatial discretization and third-order TVD Runge-Kutta time discretization methods are used. Shock-wave action on bubble,implosion and velocity field Shock effect bubbles; implosion and velocity field are simulated by means of LS-MMIC3. programmed by C++. Nu-merical results show that the Level Set interface treatment method is effective and feasible for multi-material interface treatment in comparison with the WENO method.

关键词： Euler method Level Set method shock-wave action on bubble implosion numerical simulation

Effect of lead on survival, locomotion and sperm morphology of Asian earthworm, Pheretima guillelmi

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2009年第5期21卷 691-695页

作者： ZHENG Rongquan, LI Canyang college of Chemistry and Life science, Zhejiang Normal university, Jinhua 3.1004,{3.. [a]college of Chemistry and Life science Zhejiang Normal University Jinhua 321004 China

To provide basic toxicity data for formulating risk characterization benchmarks, the effects of lead on survival, locomotion, and sperm morphology were investigated in the Asian earthworm Pheretima guillelmi. The LC50 of P. guiUelmi for 7 and 14 d were 4285＋3.9 mg/kg and 3.07＋248 mg/kg, which shows P. guillelmi can tolerate a higher concentration of lead nitrate. The average weight of the surviving earthworms decreased at concentration of 2800 mg Pb/kg soil, and the locomotor ability of earthworms exposed to a range of soil Pb concentrations showed a general decrease with increasing Pb concentrations. We also presented data depicting the sperm morphology of earthworms, which shows potential as a sensitive biomarker for measuring the effects of heavy metal on reproduction.

关键词： lead Pheretima guillelmi sperm morphology locomotion

Predictor-corrector interior-point algorithm for linearly constrained convex programming

在线全文

学校读者我要写书评

暂无评论

Journal of Central South university 2001年第3期13卷 208-212页

作者： LIANG Xi-ming (college of Information science & Engineering, Central South university, Changsh a 410083.{3.) 1. college of Information science & Engineering Central South University 410083 Changsha China

Active set method and gradient projection method are curre nt ly the main approaches for linearly constrained convex programming. Interior-po int method is one of the most effective choices for linear programming. In the p aper a predictor-corrector interior-point algorithm for linearly constrained c onvex programming under the predictor-corrector motivation was proposed. In eac h iteration, the algorithm first performs a predictor-step to reduce the dualit y gap and then a corrector-step to keep the points close to the central traject ory. Computations in the algorithm only require that the initial iterate be nonn egative while feasibility or strict feasibility is not required. It is proved th at the algorithm is equivalent to a level-1 perturbed composite Newton method. Numerical experiments on twenty-six standard test problems are made. The result s show that the proposed algorithm is stable and robust.

关键词： linearly constrained convex programming predictor corrector interior point algorithm numerical experiment

Up-conversion emissions of Er^(3.)-Yb^(3.) codoped Al_2O_3.nanoparticles by the arc discharge synthesis method

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 1043-1046页

作者： DONG Bin1, CAO BaoSheng1, FENG ZhiQing1, WANG XingJun2, LI ChengRen3.& HUA RuiNian4 1 School of science, Dalian Nationalities university, Dalian 116600, china 2 School of Electronics Engineering and Computer science, Peking university, Beijing 100871, china 3.college of Physics and Electronic Technology, Liaoning Normal university, Dalian 116029, china 4 college of Life science, Dalian Nationalities university, Dalian 116600, china 1. School of science Dalian Nationalities University Dalian 116600 China 2. School of Electronics Engineering and Computer science Peking University Beijing 100871 China 3. college of Physics and Electronic Technology Liaoning Normal University Dalian 116029 China 4. college of Life science Dalian Nationalities University Dalian 116600 China

The Er3.-Yb3. codoped Al2O3.nanoparticles with an average particle size of about 50 nm have been synthesized by an arc discharge synthesis method. The green and red up-conversion emissions centered at about 526, 547 and 677 nm, corresponding respectively to the 2H11/2→4I15/2, 4S3.2→4I15/2 and 4 F9/2→4I15/2 transitions of Er3., were detected by a 978-nm semiconductor laser diode excitation. The Annealing has evident effect on the up-conversion emissions of the samples: The red up-conversion emission is noticeable before annealing; however, the green up-conversion emission becomes predominant after annealing. The mixture of (Er,Yb)3.l5O12 and α-(Al,Er,Yb)2O3.phases is more favorable for green up-conversion emissions due to an enhancement of the ESA (I) of 4I11/2+a photon→4F7/2 and ET (III) of 2F5/2(Yb3.)+4I11/2(Er3.)→2F7/2(Yb3.)+4F7/2(Er3.) processes. The two-photon absorption up-conversion process is involved in the green and red up-conversion emissions. The results have proved that arc discharge synthesis is a new promising preparation technology for optical materials.

关键词： up-conversion Er3.-Yb3. codoped Al2O3 arc discharge synthesis

Phototoxic effect of UVR on wild type, ebony and yellow mutants of Drosophila melanogaster: Life Span, fertility, courtship and biochemical aspects

在线全文

学校读者我要写书评

暂无评论

science china(Life sciences) 2008年第10期51卷 885-893页

作者： WANG ZhePeng1,2, LIU RuiFang2, WANG AnRu3. DU LiLi1 & DENG XueMei1 1 college of Animal science and Technology, china Agricultural {3., Beijing 100094, china 2 Vocational and Technologic college, Inner Mongolia Agriculture {3., Baotou 014109, china 3.college of Veterinary Medicine, china Agricultural {3., Beijing 100094, china 1. college of Animal science and Technology China Agricultural University Beijing 100094 China 2. Vocational and Technologic college Inner Mongolia Agriculture University Baotou 014109 China 3. college of Veterinary Medicine China Agricultural University Beijing 100094 China

Melanin plays an important role in protecting organisms from ultraviolet radiation (UVR). Therefore, it is possible that differently colored strains can show different sensitivities to UVR. In the present work, life span, fertility and courtship behavior of wild type (w), ebony (e) and yellow (y) strains of Drosophila melanogaster were studied to evaluate their sensitivity to ultraviolet (UV). Because a range of photo- toxic effects of UVR are mediated through generation of free radicals, levels of free radicals, lipid per- oxide (malondialdehyde, MDA) and superoxide dismutase (SOD) activity of three strains were examined to indicate their antioxidant defending ability and oxidative status. It was shown that w always had the highest lifespan and fertility not only in the control but also in UV-exposed groups. Moreover, lifespan and fertility of e were significantly higher (P0.05). MDA levels were increased in the UV dose-dependent manner (P=0.0495). In con- clusion, our results suggested that UVR can decrease life span and fertility of flies and do harm to courtship, which may be due to oxidative damage to flies tissues (e.g. central nervous system) induced by free radicals. w had the highest tolerance to UVR, which may be ascribed to its advantage of survival under the natural condition and at high level of SOD activity. Then differences of pigment between e and y in absorbing UV, shielding agai

关键词： ultraviolet radiation Drosophila melanogaste free radicals pigment

A new DNA algorithm to solve graph coloring problem

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2, Meng Ya3.and Meng Dazhi2(1. National Laboratory of Pattern Recognition,Institute of Automation, Chinese Academy of sciences, Beijing 100080, china 2. college of Applied sciences, Beijing university of Technology, Beijing 100022, china 3. School of science, Beijing Institute of Technology, Beijing 100081, china) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China college of Applied sciences Beijing University of Technology Beijing 100022 China School of science Beijing Institute of Technology Beijing 100081 China

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.

Zero asymptotic Lipschitz distance and finite Gromov-Hausdorff distance

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china Mathematics 2007年第3期50卷 345-350页

作者： Luo-fei LIU college of Mathematics and Computer science, Jishou university, Jishou 416000,{3. college of Mathematics and Computer science Jishou University Jishou416000 China

We give an example which shows that the Burago’s bounded distance theorem does not hold in a non-intrinsic metric case. The argument is based on the classical answer to the densest circle packing problem in ?2.

关键词： asymptotic Lipschitz distance Gromov-Hausdorff distance densest circle packing 51K05 05B40

Preparation and Enhanced Daylight-Induced Photo-Catalytic Activity of Transparent C-Doped TiO_2 Thin Films

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(Materials science) 2010年第5期25卷 738-742页

作者：白爱英 college of Materials science and Engineering Taiyuan University of Technology Xin Zhou Vocational Technical college

The transparent C-doped TiO2 nanostructure films were fabricated on the silicate glass substrates by sol-gel spin-coated method. The as-prepared films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, UV-visible absorption spectra （UV-vis） and X-ray photoelectron spectroscopy （XPS）. The photocatalytic activity was evaluated via the photocatalytic oxidation of methylene blue in aqueous under daylight irradiation at room temperature. The results show that the daylight-induced photocatalytic activities of the as-prepared films are improved by the C-doping. The calcination temperatures significantly affect the morphology, microstructure and photocatalytic activity of the as-prepared samples. At 723.K, the C-doped TiO2 films exhibit the highest photocatalytic activity due to the synergetic effects of good crystallization, appropriate oxygen vacancies and strong absorption in the near UV and visible-light region.

关键词： C-doped TiO2 films daylight-induced photocatalytic activity spin-coated

Optimal error bound of restricted Monte Carlo integration on anisotropic Sobolev classes

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2006年第6期16卷 588-593页

作者： GAO Wenhua, YE Peixin and WANG Hui (college of Mathematics and System sciences, Xinjiang university, Urumqi 83.046,{3. School of Mathematical sciences and LPMC, Nankai university, Tianjin 3.0071,{3. Department of Mathematics, Ily Teachers' college, Yining 83.000,{3. college of science, Hehai university, Nanjing 210098,{3.) [a]college of Mathematics and System sciences Xinjiang University Urumqi China [b]School of Mathematical sciences and LPMC Nankai University Tianjin China [c]Department of Mathematics Ily Teachers College Yining China [d]college of science Hehai University Nanjing China

We study the restricted Monte Carlo integration error for anisotropic Sobolev classes. Results prove that with O(log2 n) random bits we have the optimal order for the n-th minimal Monte Carlo integration error with ar... 详细信息

关键词： Monte Carlo integration random bits anisotropic Sobolev classes.