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FINITE ELEMENT ANALYSIS OF A LOCAL EXPONENTIALLYFITTED SCHEME FOR TIME-DEPENDENTCONVECTION-DIFFUSION PROBLEMS

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Journal of Computational Mathematics 1999年第3期17卷 225-232页

作者： Yue, XY Jiang, ls Shih, TM Suzhou Univ Dept Math Suzhou 215006 Peoples R China Tongji Univ Inst Math Shanghai 200092 Peoples R China Hong Kong Polytech Univ Dept Appl Math Hong Kong Hong Kong

In [16], Stynes and O' Riordan(91) introduced a local exponentially fitted finite element (FE) scheme for a singularly perturbed two-point boundary value problem without turning-point. An E-uniform h(1/2)-order accuracy was obtain for the epsilon-weighted energy norm. And this uniform order is known as an optimal one for global exponentially fitted FE schemes (see [6, 7, 12]). In present paper, this scheme is used to a parabolic singularly perturbed problem. After some subtle analysis, a uniformly in epsilon convergent order h\ln h\(1/2) + tau is achieved (h is the space step and tau is the time step), which sharpens the results in present literature. Furthermore, it implies that the accuracy order in [16] is actuallay h\ln h\(1/2) rather than h(1/2).

关键词： singularly perturbed exponentially fitted uniformly in epsilon convergent Petrov-Galerkin finite element method

Irritable bowel syndrome:A clinical review

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World Journal of Gastroenterology 2014年第34期20卷 12144-12160页

作者： Rosa ls Soares Internal Medicine Department Faculty of MedicineFederal Fluminense UniversityRio de Janeiro 24030-210Brazil

Irritable bowel syndrome (IBS) remains a clinical challenge in the 21st century. It’s the most commonly diagnosed gastrointestinal condition and also the most common reason for referral to gastroenterology clinics. Its can affect up to one in five people at some point in their lives, and has a significantly impact of life quality and health care utilization. The prevalence varies according to country and criteria used to define IBS. Various mechanisms and theories have been proposed about its etiology, but the biopsychosocial model is the most currently accepted for IBS. The complex of symptoms would be the result of the interaction between psychological, behavioral, psychosocial and environmental factors. The diagnosis of IBS is not confirmed by a specific test or structural abnormality. It is made using criteria based on clinical symptoms such as Rome criteria, unless the symptoms are thought to be atypical. Today the Rome Criteria III is the current gold-standard for the diagnoses of IBS. Secure positive evidence of IBS by means of specific disease marker is currently not possible and cannot be currently recommended for routine diagnosis. There is still no clinical evidence to recommend the use of biomarkers in blood to diagnose IBS. However, a number of different changes in IBS patients were demonstrated in recent years, some of which can be used in the future as a diagnostic support. IBS has no definitive treatment but could be controlled by non-pharmacologic management eliminating of some exacerbating factors such certain drugs, stressor conditions and changes in dietary *** traditional pharmacologic management of IBS has been symptom based and several drugs have been used. However, the cornerstone of its therapy is a solid patient physician relationship. This review will provide a summary of pathophysiology, diagnostic criteria and current and emerging therapies for IBS.

关键词： Irritable bowel syndrome Clinical review Pathogenesis Diagnostic Treatment Biopsychosocial model

Low Temperature Deposition of Titanium Nitride

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Journal of Materials Science & Technology 1998年第4期14卷 289-293页

作者： Wen, ls Huang, RF Chinese Acad Sci Inst Met Res Shenyang 110015 Peoples R China

Low temperature deposition (LTD) is an actual frontier in materials sicence and engineering, especially for thin film technology. In this paper the fundamentals and processing of low temperature deposition of TiN coating are reviewed. The prerequisites of a low temperature deposition process are enough good densification, hardness and adhesion of the deposited coating. The fundamentals of low temperature deposition are structure zone model and nonequilibrium plasma vapor growth in a combined DC and pulsed electromagnetic fields, namely a combination of a DC bias voltage superimposed by a DC pulsed bias voltage with variable frequency and peak voltage height. Low temperature deposition processing can be realized simply with only stationary electric fields. However, sensitivity of the product quality to the process parameters is the main barrier of this processing in the way to mass production. Low temperature deposition processing using the effects of a combined DC and pulsed electromagnetic fields has attained some promising results for the future commercialization. But they need still further systematic and deep study. The application of low temperature deposition processing is not limited in range of low melting substrate materials. It is also important for internal stress control, defect minimization, microstructure densification and performance improvement for coatings on broad spectrum of substrate materials as well as for different types of applications.

关键词： PUlsE BIAS VOLTAGE RESIDUAL-STRESS ION-BOMBARDMENT HARD COATINGS PVD COATINGS FILM GROWTH TIN ARC RESISTANCE SUBSTRATE

A Safe and Brief Way for Preparing Anhydrous LnCl_3 (Ln=Sc, Y, La to Lu)

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Rare Metals 2000年第2期19卷 157-161,152页

作者： Li, Y Wang, ls Wang, YH Department of Chemistry Northeastern University Shenyang 110006 China

Anhydrous lanthanide chlorides LnCl 3 (Ln=Sc, Y, La to Lu except for Pm), which are difficult to prepare in other ways, were prepared by chemical vapor transport (CVT) process. Rare earth oxide reacted with Al 2Cl 6 at 300℃ to produce LnCl 3, which was then separated from other solids by means of CVT at a temperature gradient from 400 to 180℃. Residual Al 2Cl 6 (g) was removed by carrier of dry N 2 gas at 200℃. The yielding rates were >90%, and the purity of products was >99.5%.

关键词： Anhydrous lanthanide chlorides AlCl 3 Chemical vapor transport

A Calculation Method for Incidence and Reflection of Irregular Waves Along Seawalls

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China Ocean Engineering 1997年第3期12卷 305-314页

作者： Zhu, ls Sui, SF Chinese Acad Sci S China Sea Inst Oceanol Guangzhou 510301 Peoples R China

Some researches have been made in this aspect. In the method by Walton Jr.(1992), incident waves are supposed to be the overlapping result of M component waves with different frequencies which may take different directions, the direction of incident waves should be available in advance, but in fact the direction of incident waves is not available. In our study, incident waves are supposed to be composed of M overlapping component waves with different frequencies, and different frequencies have different directions. Based on the irregular wave reflection theory, the calculation formulas of wave direction, complex amplitude of incident waves, and complex amplitude of reflected waves in surface which are composed of component waves are derived by means of discrete Fourier transform. Then, the frequency spectra of incident waves and reflected waves and the reflection coefficient of waves with corresponding frequencies are obtained. Verification of the method and the calculation results from in-situ measured data indicate that the method is reliable and highly accurate.

关键词： irregular wave seawall incidence and reflection calculation method

Cellular and molecular mechanisms in the pathogenesis of liver fibrosis:An update

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World Journal of Gastroenterology 2014年第23期20卷 7260-7276页

作者： Gülsüm ?zlem Elpek Department of Pathology Akdeniz University Medical School07070 AntalyaTurkey

There have been considerable recent advances towards a better understanding of the complex cellular and molecular network underlying liver *** data indicate that the termination of fibrogenic processes and the restoration of deficient fibrolytic pathways may allow the reversal of advanced fibrosis and even ***,efforts have been made to better clarify the cellular and molecular mechanisms that are involved in liver *** of hepatic stellate cells(HSCs)remains a central event in fibrosis,complemented by other sources of matrix-producing cells,including portal fibroblasts,fibrocytes and bone marrow-derived *** cells converge in a complex interaction with neighboring cells to provoke scarring in response to persistent *** the interaction of different cell types,revealing the effects of cytokines on these cells and characterizing the regulatory mechanisms that control gene expression in activated HSCs will enable the discovery of new therapeutic ***,the characterization of different pathways associated with different etiologies aid in the development of disease-specific *** article outlines recent advances regarding the cellular and molecular mechanisms involved in liver fibrosis that may be translated into future *** pathogenesis of liver fibrosis associated with alcoholic liver disease,non-alcoholic fatty liver disease and viral hepatitis are also discussed to emphasize the various mechanisms involved in liver fibrosis.

关键词： Liver Liver fibrosis Cirrhosis Fibrogenesis Hepatic stellate cells Myofibroblast Extracellular matrix

Polymerization of Methyl Methacrylate by Diisopropylamido bis(methylcyclopentadienyl) ytterbium Complex

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Chinese Chemical Letters 1997年第7期8卷 637-638页

作者： Mao, ls Xue, MQ Shen, Q SUZHOU UNIV DEPT CHEMSUZHOU 215006PEOPLES R CHINA

It was first found that diisopropylamido bis(methylcyclopentadienyl) ytterbium complex (MeCp)(2)YbN(i-Pr)(2)(THF) exhibits extremely high catalytic activity in the polymerization of methyl methacrylate. The reactions can be carried out over a quite broad range of polymerization temperatures from -78 degrees C to 40 degrees C. The results of GPC (gel permeation chromatography) indicate that the molecular weight distribution (Mw/Mn) becomes broad with the increase of temperature.

关键词： THF Polymerization of Methyl Methacrylate by Diisopropylamido bis methylcyclopentadienyl ytterbium Complex

Microstructure and Properties of WC-Co/NiCrBSi Brazing Coating

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Journal of Materials Science & Technology 1999年第3期15卷 283-285页

作者： Lu, SP Guo, Y Chen, ls Acad Sinica Inst Met Res Shenyang 110015 Peoples R China

Through rolling technology, a flexible metal cloth consisting of metal powder (NiCrBSi powder or WC-Co powder) and organism in a certain ratio were made, which could be used as brazing coating raw materials. WC-Co/NiCrBSi wear coating was fabricated through high temperature vacuum brazing after the flexible metal clothes were assembled on 42CrMo steel surface. The tensile strengths of coating self and coating/matrix approached to 100 similar to 140 MPa and 300 similar to 360 MPa, respectively, at different brazing parameters. Effect of Co on the wear property of the coating was analyzed. The abrasive wear property of WC-Co/NiCrBSi brazing coating is better than WC-17Co/NiCrBSi flame overlaying and CoCrW overlaying.

关键词： WC Co Microstructure and Properties of WC-Co/NiCrBSi Brazing Coating

Defect aggregates in the Sr_2MgSi_2O_7 persistent luminescence material

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Journal of Rare Earths 2011年第12期29卷 1130-1136页

作者： Jorma Hls Taneli Laamanen Mika Lastusaari Pavel Novák Department of Chemistry University of Turku Turku University Centre for Materials and Surfaces(MatSurf) Graduate School of Materials Research(GSMR) Institute of Physics Academy of Sciences of the Czech Republic

The crystal and electronic structure of the Eu^2＋ doped and defect containing Sr2MgSi2O7 persistent luminescence material were studied using the density functional theory （DFT）. The defects may act as energy storage or even luminescence quenching centres in these materials, however their role is very difficult to confirm experimentally. The probability of vacancy formation was studied using the total energy of the defect containing host. Significant structural modifications in the environment of the isolated defects, especially the strontium vacancy, as well as defect aggregates were found. The experimental band gap energy of Sr2MgSi2O7 was well reproduced by the calculations. The defect induced electron traps close to the host＇s conduction band were found to act as energy storage sites contributing to its efficient persistent luminescence. The interactions between the defects were found to modify both the Eu^2＋ 4f^7 ground state energy as well as the trap structure. The effect of charge compensation induced by the rare earth co-doping on the defect structure and energy storage properties of the persistent luminescence materials was discussed.

关键词： strontium magnesium disilicate vacancy defect aggregate persistent luminescence density functional theory calculations rare earths