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HIGH ACCURACY ANALYSIS OF THE WILSON ELEMENT

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Journal of Computational Mathematics 1999年第2期17卷 113-124页

作者： Luo, P Lin, Q chinese acad sci Inst Math Beijing 100080 Peoples R China chinese acad sci Inst Syst Sci Beijing 100080 Peoples R China

In this paper, the Wilson nonconforming finite element is considered for solving a class of second-order elliptic boundary value problems. Based on an asymptotic error expansion for the Wilson finite element, the glob... 详细信息

关键词： finite elements defect correction global superconvergence Wilson element

Characterization of the Songhua River sediments and evaluation of their adsorption behavior for nitrobenzene

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Journal of Environmental sciences 2008年第7期20卷 796-802页

作者： Liu Ruiping Liu Huijuan Wan Dongjin Yang Min chinese acad sci Ecoenvironm Sci Res Ctr Beijing 100085 Peoples R China chinese acad sci Grad Univ Beijing 100049 Peoples R China

The explosion at a plant of the Jilin Petrochemical Corporation on 13 November,2005,and the spill of an estimated 100 t of toxic substances (nitrobenzene as the main component) into the Songhua River received worldwide *** study has focused on the adsorption behavior of nitrobenzene that spilled onto sediments along the Songhua River,which was one of the efforts to evaluate the fate of nitrobenzene after the spillage *** organic carbon contents of these sediments along the Songhua River var...

关键词： nitrobenzene adsorption sediment characteristics organic carbon content particle size distribution

A PRECONDITIONER FOR COUPLING SYSTEM OF NATURAL BOUNDARY ELEMENT AND COMPOSITE GRID FINITE ELEMENT

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Journal of Computational Mathematics 2002年第2期20卷 165-174页

作者： Qi-ya Hu De-hao Yu chinese acad sci Acad Math & Syst Sci ICMSEC LSEC Beijing 100080 Peoples R China

Discusses a coupling boundary element methods with finite element method for the Dirichlet exterior problems. Information on the natural boundary reduction; Discussion on the composite grid discretization; Details on ... 详细信息

关键词： natural boundary reduction composite grid error estimate preconditioner condition number

NONLINEAR BOUNDARY STABILIZATION OF WAVE EQUATIONS WITH VARIABLE COEFFICIENTS

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chinese Annals of Mathematics,Series B 2003年第2期24卷 239-248页

作者： FENG SHAOJI FENG DEXING academy of Mathematics and Systems science, chinese academy of sciences, Beijing 100080, China. E-mail: fengshaoji0164@sina.comacademy of Mathematics and Systems science, chinese academy of sciences, Beijing 100080, China. E-mail: dxfeng@*** chinese acad sci Acad Math & Syst Sci Beijing 100080 Peoples R China

The wave equation with variable coefficients with a nonlinear dissipative boundary feedbackis studied. By the Riemannian geometry method and the multiplier technique, it is shown thatthe closed loop system decays exponentially or asymptotically, and hence the relation betweenthe decay rate of the system energy and the nonlinearity behavior of the feedback function isestablished.

关键词： Wave equations Nonlinear boundary feedback Exponential decay Asymptotic decay Riemannian manifold

Soil fungistasis and its relations to soil microbial composition and diversity:A case study of a series of soils with different fungistasis

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Journal of Environmental sciences 2008年第7期20卷 871-877页

作者： Wu Minna Zhang Huiwen Ll Xinyu Zhang Yan Su Zhencheng Zhang Chenggang chinese acad sci Inst Appl Ecol Shenyang 110016 Peoples R China chinese acad sci Grad Univ Beijing 100039 Peoples R China

Fungistasis is one of the important approaches to control soil-borne plant *** hypotheses about the mechanisms for soil fungistasis had been established,which mainly focused on the soil bacterial community composition,structure,diversity as well as *** this study,the bacterial community composition and diversity of a series of soils treated by autoclaving,which coming from the same original soil sample and showing gradient fungistasis to the target soil-borne pathogen fungi Fusarium grami...

关键词： soil fungistasis 16S rDNA clone library microbial diversity bacterial community composition

Global trends and hotspots of type 2 diabetes in children and adolescents:A bibliometric study and visualization analysis

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World Journal of Diabetes 2025年第1期16卷 140-168页

作者： Fang-Shuo Zhang Hai-Jing Li Xue Yu Yi-Ping Song Yan-Feng Ren Xuan-Zhu Qian Jia-Li Liu Wen-Xun Li Yi-Ran Huang Kuo Gao School of Acupuncture-Moxibustion and Tuina Beijing University of Chinese MedicineBeijing 100029China School of Traditional chinese Medicine Beijing University of Chinese MedicineBeijing 100029China

BACKGROUND Epidemiological surveys indicate an increasing incidence of type 2 diabetes mellitus(T2DM)among children and adolescents *** to rapid disease progression,severe long-term cardiorenal complications,a lack of effective treatment strategies,and substantial socioeconomic burdens,it has become an urgent public health issue that requires management and *** T2DM differs from adult *** a significant increase in our understanding of youth-onset T2DM over the past two decades,the related review and evidence-based content remain *** To visualize the hotspots and trends in pediatric and adolescent T2DM research and to forecast their future research *** This study utilized the terms“children”,“adolescents”,and“type 2 diabetes”,retrieving relevant articles published between 1983 and 2023 from three citation databases within the Web of science Core Collection(sci,Ssci,Esci).Utilizing CiteSpace and VoSviewer software,we analyze and visually represent the annual output of literature,countries involved,and participating *** allows us to predict trends in this research *** analysis encompasses co-cited authors,journal overlays,citation overlays,time-zone views,keyword analysis,and reference analysis,*** A total of 9210 articles were included,and the annual publication volume in this field showed a steady growth *** United States had the highest number of publications and the highest *** United States also had the most research institutions and the strongest research *** global hot journals were primarily diabetes professional journals but also included journals related to nutrition,endocrinology,and *** analysis showed that research related to endothelial dysfunction,exposure risk,cardiac metabolic risk,changes in gut microbiota,the impact on comorbidities and outcomes,etc.,were emerging *** have maintained their popularity in this field,sugges

关键词： Child Adolescent Type 2 diabetes mellitus Bibliometrics Knowledge mapping Visualization CiteSpace VOSviewer

Synthesis and Characterization of Nanocrystalline Ni-Ti and Ni-Cr Powders by Mechanical Alloying

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Journal of Materials science & Technology 1997年第2期13卷 86-90页

作者： Chen, SQ Zhou, YC Li, YY He, SH chinese acad sci BEIJING 100864PEOPLES R CHINA

Nanocrystalline powders in the Ni-Ti and Ni-Cr systems were prepared by mechanical alloying (MA) of elemental crystalline powders in an inert atmosphere. The microstructure of the mechanically alloyed powders were characterized by XRD and TEM. The ball-milling process results in a drastic decrease of the crystallite size to the nanometer scale. X-ray diffraction analysis reveals that in the Ni-Cr system, no diffraction peaks from NiCr compound were observed even after 20 h of bail milling; while the lattice parameter of Ni increased with the milling time. In the Ni-Ti system, amorphous alloy was formed. Crystalline intermetallic compounds were obtained by post heat treatment of the amorphous alloy. The crystallization temperature of the amorphous NiTi alloy was obtained by DSC measurement.

关键词： Nanostructured materials

THE CALCULUS OF GENERATING FUNCTIONS AND THE FORMAL ENERGY FOR HAMILTONIAN ALGORITHMS

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Journal of Computational Mathematics 1998年第6期16卷 481-498页

作者： Feng K.(ICMSEC, chinese academy of sciences) chinese acad sci ICMSEC Beijing 100864 Peoples R China

In [2-4], symplectic schemes of arbitrary order are constructed by generating functions. However the construction of generating functions is dependent on the chosen coordinates. One would like to know that under what circumstance the construction of generating functions will be independent of the coordinates. The generating functions are deeply associated with the conservation laws, so it is important to study their properties and computations. This paper will begin with the study of Darboux transformation, then in section 2, a normalization Darboux transformation will be defined naturally. Every symplectic scheme which is constructed from Darboux transformation and compatible with the Hamiltonian equation will satisfy this normalization condition. In section 3, we will study transformation properties of generator maps and generating functions. Section 4 will be devoted to the study of the relationship between the invariance of generating functions and the generator maps. In section 5, formal symplectic erengy of symplectic schemes are presented.

关键词： generating function calculus of generating functions Darboux transformation cotangent bundles Lagrangian submanifold invariance of generating function formal energy

SOME PROPERTIES OF INTEGRATED BISEMIGROUPS

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Acta Mathematica scientia 2001年第1期21卷 50-60页

作者：许跟起冯德兴 chinese acad sci Acad Math & Syst Sci Inst Syst Sci Beijing 100080 Peoples R China

Some properties of integrated bisemigroup S(t) of linear operators on a Banach space X are studied. The structure of the positive and negative subspaces and the operation of integrated bisemigroup on corresponding differentiable subspace C-n are established. respectively. The decomposition of the infinitesimal generator A of S(t) and other interested problems are also considered. As application, an abstract boundary value problem is discussed.

关键词： integrated bisemigroup positive and negative subspace abstract differential equation boundary value problem