检索结果-南通市图书馆

EXTRAPOLATION AND A-POSTERIORI ERROR ESTIMATORS OF PETROV-GALERKIN METHODS FOR NON-LINEAR VOLTERRA INTEGRO-DIFFERENTIAL EQUATIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2001年第4期19卷 407-422页

作者： Shu-hua Zhang (Department of mathematical sciences, university of Alberta, Edrmonton, Alberta, Canada T6G 2G1) Tao Lin (Department of Mathematics, Virginia Tech, Blacksburg VA 24061) Yan-ping Lin (Department of mathematical sciences, university of Alberta university of Alberta 加拿大 T6G 2G1 Virginia Tech 美国 VA 24061 university of Alberta 加拿大 T6G 2G6

In this paper we will show that the Richardson extrapolation can be used to enhance the numerical solution generated by a Petrov-Galerkin finite element method for the initial value problem for a nonlinear Volterra integro-differential equation. As by-products, we will also show that these enhanced approximations can be used to form a class of posteriori estimators for this Petrov-Galerkin finite element method. Numerical examples are supplied to illustrate the theoretical results.

关键词： Volterra integro-differential equations Petrov-Galerkin finite element methods Asymptotic expansions Interpolation post-processing A-posteriori error estimators.

Modified accumulation of selected heavy metals in Bt transgenic rice

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2009年第11期21卷 1607-1612页

作者： WANG Haiyan, HUANG Jianzhong, YE Qingfu, WU Dianxing, CHEN Ziyuan Institute of Nuclear Agricultural sciences, Key Laboratory of Nuclear Agricultural sciences of Ministry of Agriculture and zhejiang Province, zhejiang university, Hangzhou 310029, China [a]Institute of Nuclear Agricultural sciences Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province Zhejiang University Hangzhou 310029 China

Safety assessment of genetically modified crops generally does not take into account the potential hazard of altered patterns of heavy metal accumulation in plants. A pot experiment was conducted under greenhouse conditions to evaluate the impact of heavy metal amendments on the accumulation of Cd, Cu, Pb and Zn in a Bt transgenic rice Ke-Ming-Dao （KMD） and its wild-type Xiushui 11 （Xs11）. In control soils, significant difference was only found in contents of Cu （p 〈 0.01） and Pb （p 〈 0.05） in straw between KMD and Xs11. At three levels of Cd amendments （5, 10, and 20 mg/kg）, the Cd contents in grain and straw of KMD were significantly higher than those of Xs11, and all grain Cd contents were significantly higher than the International Criteria （0.2-0.4 mg/kg） as specified by the Codex Alimentarius Commission （CAC）. These results implied that it may be unsafe for growing Bt transgenic rice in heavily Cd-polluted areas. No significant difference in Zn was found between the two varieties with the exception of roots at Zn amendment level of 600 mg/kg, while Pb contents in KMD were much higher in the straw at the lead amendment level of 1000 mg/kg and in the root at 250 mg Pb/kg. Data on the heavy metal accumulation patterns for the genetically modified rice may be used for the selection of growing areas as well as for plant residue management for Bt rice.

关键词： Bt transgenic rice heavy metal bioaccumulation trace elements

Hereditary C~*-subalgebras and comparison of positive elements

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2010年第6期53卷 1565-1570页

作者： WEI ChangGuo1,& WANG LiGuang2 1School of mathematical sciences,Ocean university of China,Qingdao 266071,China 2School of mathematical sciences,Qufu Normal university,Qufu 273165,China 1. School of mathematical sciences Ocean University of China Qingdao 266071 China2. School of Mathematical Sciences Qufu Normal University Qufu 273165 China

Characterizations of hereditary subalgebras generated by subsets of a C*-algebra are given through open *** these results,we give some equivalent conditions of comparison of positive elements.

关键词： hereditary subalgebra open projection positive element

2023 Guideline for the management of hypertension in the elderly population in China

在线全文

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2024年第6期21卷 589-630页

作者： Hypertension Branch of Chinese Geriatrics Society,Beijing Hypertension Association,National Clinical Research center of the Geriatric Diseases Qi HUA Li FAN Zeng-Wu WANG Jing LI 不详 Xuanwu Hospital Capital Medical UniversityBeijingChina Chinese PLA General Hospital BeijingChina Fuwai Hospital Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Preamble Hypertension is one of the most common chronic diseases and the primary risk factor for stroke,myocardial infarction and even cardiovascular *** than half of the elderly population has high blood *** people are a unique group,and strategies for the prevention,diagnosis,evaluation,and treatment of hypertension in elderly individuals differ significantly from those in the general population.

关键词： hypertension prevention diagnosis

Every Banach space with a w*-separable dual hasa 1+ε-equivalent norm with the ball covering property

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2009年第9期52卷 1869-1874页

作者： CHENG LiXin, SHI HuiHua & ZHANG Wen School of mathematical sciences, Xiamen university, Xiamen 361005, China School of mathematical sciences Xiamen University Xiamen China

A normed space is said to have ball-covering property if its unit sphere can be contained in the union of countably many open balls off the origin. This paper shows that for every ε>0 every Banach space with a w*-sep... 详细信息

关键词： ball-covering property renorming Banach space

On consensus protocols for high-order multiagent systems

在线全文

学校读者我要写书评

暂无评论

控制理论与应用（英文版） 2010年第4期8卷 406-412页

作者： Jing KUANG,Jiandong ZHU (School of mathematical sciences,Nanjing Normal university,Nanjing Jiangsu 210097,China) School of mathematical sciences Nanjing Normal University Nanjing Jiangsu China

In this paper,the static consensus problem and the dynamic consensus problem are considered for a class of high-order multiagent *** the proposed consensus protocols,necessary and sufficient conditions for the consensus problems are *** the static consensus protocol,the desired consensus speed can be achieved by adjusting feedback *** show the effectiveness of the proposed consensus protocols.

关键词： Consensus Multiagent systems Graph theory

THE REGULARITY OF THE FREE BOUNDARY FOR STRIKE RESET OPTION

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2010年第5期30卷 1721-1729页

作者：杨舟 School of mathematical sciences South China Normal University

A strike reset option is an option that allows its holder to reset the strike price to the prevailing underlying asset price at a moment chosen by the holder. The pricing model of the option can be formulated as a parabolic variational inequality and the optimal reset strategy is the free boundary. The smoothness of the free boundary in some cases was showed in our article published in JDE. We would prove its smoothness in the other case in this paper by a generalized comparison principle for the variational inequality.

关键词： strike reset option free boundary variational inequality the comparison principle

Global Existence of Classical Solutions for Some Oldroyd-B Model via the Incompressible Limit

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2006年第5期27卷 565-580页

作者： Zhen LEI School of mathematical sciences, Fudan university, Shanghai 200433, China School of Mathematics and Statistics, Northeast Normal university, Changchun 130024, China. School of mathematical sciences Fudan University Shanghai 200433 China School of Mathematics Statistics Northeast Normal University Changchun 130024 China

In this paper, we prove local and global existence of classical solutions for a system of equations concerning an incompressible viscoelastic fluid of Oldroyd-B type via the incompressible limit when the initial data ... 详细信息

关键词： Incompressible limit Global existence Oldroyd model

Raising approximation order of refinable vector by increasing multiplicity

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2006年第1期49卷 86-97页

作者： YANG Shouzhi & PENG Lizhong Department of Mathematics, Shantou university, Shantou 515063, China LMAM, School of mathematical sciences, Peking university, Beijing 100871, China Department of Mathematics Shantou University Shantou 515063 China LMAM School of Mathematical Sciences Peking University Beijing 100871 China

An algorithm is presented for raising an approximation order of any given orthogonal multiscaling function with the dilation factor a. Let φ(x) = [φ1(x),φ2(x),…,φr(x)]T be an orthogonal multiscaling function with the dilation factor a and the approximation order m. We can construct a new orthogonal multiscaling function φnew(x) = [ φT(x). f3r+1(x),φr+2(x),…,φr+s(x)}T with the approximation order m + L(L ∈ Z+). In other words, we raise the approximation order of multiscaling function φ(x) by increasing its multiplicity. In addition, we discuss an especial setting. That is, if given an orthogonal multiscaling function φ(x) = [φ1 (x), φ2(x), …, φr(x)]T is symmetric, then the new orthogonal multiscaling function φnew(x) not only raise the approximation order but also preserve symmetry. Finally, some examples are given.

关键词： orthogonal, multiscaling functions, approximation order, symmetry.