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Singular perturbation analysis of dynamic fields in a thermoelastic solid with a small surface-breaking crack

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acta Mechanica Sinica 2006年第5期22卷 449-454页

作者： E. Zhelezina liv.ac.uk A. B. Movchan I. S. Jones ljmu.ac.uk Department of Mathematical Sciences University of Liverpool Liverpool L69 3BX UK e-mail: ezzh School of Engineering John Moores University Liverpool L3 3AF UK e-mail: i.s.jones

An asymptotic analysis is presented for a dynamic problem of a semi-infinite isotropic thermoelastic solid with a small surface breaking crack. The exterior surface of the solid is subjected to a series of short thermal pulses. The crack surface is traction free and an ideal thermal contact is assumed across the crack. The stress intensity factor is asymptotically evaluated as a function of the crack depth and time. The effect of a boundary layer associated with the diffusive term is identified. The theoretical model is supplied with numerical simulations.

关键词： Thermoelasticity Surface breakingcrack Weight function method Stress intensity factor Thermal shock

Barrett's metaplasia:clinical implications

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World Journal of Gastroenterology 2001年第4期7卷 563-565页

作者： SauidIshaq bham ac.uk JanuszAJankowski Epithelial Laboratory Division of Medical SciencesUniversity of BirminghamEdgbastonB15 2 THUK This study is supported by the Cancer Research CampaignImperial Cancer Research Fund and Medical Research Council.Correspondence to:Dr.Janusz A Jankowski MD PhD FRCPEpithelial LaboratoryDivision of Medical SciencesUniversity of BirminghamEdgbastonB15 2THUK.j.jankowski

The incidence of Barretts metaplasia (BM) as well as Barrett' s adenocarcinoma (BA) has been increasing in western populations. The prognosis of BA is worse because individuals present at a late stage. Attempts have been made to intervene at early stage using surveillance programmes, although proof of efficacy of endoscopic surveillance is lacking, particularly outside the specialist centres. The management of BM needs to be evidencebased as there is a lack clarity about how best to treat this condition. The role of proton pump inhibitors and antireflux surgery to control reflux symptoms is *** adequate control of gastroesophageal reflux early in the disease alters the natural history of Barrett' s change once it has developed and or prevents it in patients with gastroesophageal reflux disease but with no Barrett' s change remains unanswered. There is much to be learned about BM. Thus there is great need for carefully designed large randomised controlled trials to address these issues in order to determine how best to manage patients with BM.

关键词： Barrett Esophagus Humans Incidence Mass Screening Metaplasia Prevalence Research Support, Non-U.S. Gov't

Simply-typed Underdeterminism

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Journal of Computer Science & Technology 1998年第6期13卷 491-508页

作者： Ewen Denney(LFCS, Department of Computer Science, Universitg of EdinburphKings Buildings, Edinburph EH9 3JZ, Scotland)E-mail: ewd@dcs.ed.ac.uk LFCS Department of Computer Science University of Edinburgh Edinburgh Scotland

An extension of the simply-typed lambda calculus with constructs for expressing a notion calledunderdeterminism is studied. This allows us to interpret notions of stub and skeleton used in top-down program development. We axiomatise a simple notion of program refinement, and give a semantics, for which the calculus is proved sound and complete.

关键词： Refinement lambda-calculus Henkin models

The Kinematic Theory of Solar Dynamo

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Chinese Journal of Astronomy and Astrophysics 2003年第1期3卷 12-32,i001页

作者： Ke-Ke Zhang and Xin-Hao LiaoSchool of Mathematical Sciences, University of Exeter, EX4 4QE, uk kzhang@ex.ac.ukShanghai Astronomical Observatory, Shanghai 200030 xhliao@*** School of Mathematical Sciences University of Exeter EX4 4QE UK Shanghai Astronomical Observatory Shanghai 200030 China

Generation of the Sun's magnetic fields by self-inductive processes in the solar electrically conducting interior, the solar dynamo theory, is a fundamentally important subject in astrophysics. The kinematic dynamo theory concerns how the magnetic fields are produced by kinematically possible flows without being constrained by the dynamic equation. We review a number of basic aspects of the kinematic dynamo theory, including the magnetohydrodynamic approximation for the dynamo equation, the impossibility of dynamo action with the solar differential rotation, the Cowling's anti-dynamo theorem in the solar context, the turbulent alpha effect and recently constructed three-dimensional interface dynamos controlled by the solar tachocline at the base of the convection zone.

关键词： Solar magnetic fields - kinematic dynamos - magnetohydrody- namics

Counting Function Asymptotics and the Weak Weyl-Berry Conjecture for Connected Domains with Fractal Boundaries

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acta Mathematica Sinica,English Series 1998年第2期14卷 261-276页

作者： Chen Hua (Department of Mathematics,Wuhan University,Wuhan 430072,China)(Email:chenhua@whu,***)Brian D.Sleeman (School of Mathematics,University of Leeds,Leeds LS2 9JT,England,uk)(Email:bds@amsta.leeds,ac.uk) Department of Mathematics Wuhan University Wuhan China School of Mathematics University of Leeds Leeds England UK

In this paper,we study the spectral asymptotics for connected fractal domains and Weyl-Berry *** prove,for some special connected fractal domains,the sharp estimate for second term of counting function asymptotics,which implies that the weak form of the Weyl- Berry conjecture holds for the ***,we also study a naturally connected fractal domain,and we prove,in this case,the weak Weyl-Berry conjecture holds as well.

关键词： Connected fractal domain Counting function Weyl-Berry conjecture

A Force-Based Grid Manipulator for ALE Calculations in a Lobe Pump

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Journal of Thermal Science 2003年第4期12卷 318-322,370页

作者： John Vande Voorde rug.ac.be Jan Vierendeels rug.ac.be Erik Dick rug.ac.be Department of Flow Heat and Combustion Mechanics Ghent University Belgium E-mail: John.VandevoordeDepartment of Flow Heat and Combustion Mechanics Ghent University Belgium E-mail: John.VandevoordeDepartment of Flow Heat and Combustion Mechanics Ghent University Belgium E-mail: John.Vandevoorde

In this paper, a time-dependant calculation of flow in a lobe pump is presented. Calculations are performed using the arbitrary Lagrangean Eulerean (ALE) method. A grid manipulator is needed to move the nodes between time steps. The used grid manipulator is based on the pseudo-force idea. This means that each node is fictitiously connected with its 8 neighbours via fictitious springs. The equilibrium of the resulting pseudo spring forces defines the altered position of the nodes. The grid manipulator was coupled with a commercial flow solver and the whole was tested on the flow through a three-lobe lobe pump. Results were obtained for a rotational speed of 460 rpm and incompressible silicon oil as fluid.

关键词： ALE arbitrary Lagrangean Eulerean moving grids lobe pump.

Near-infrared fluorescence imaging guided surgery in colorectal surgery

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World Journal of Gastroenterology 2022年第12期28卷 1284-1287页

作者： Sung uk Bae Department of Surgery School of MedicineDongsan Medical CenterKeimyung UniversityDaegu 700-712South Korea

Near infrared fluorescence using indocyanine green is beneficial for visual assessment of blood vessels,blood flow,and tissue perfusion,sentinel lymph node biopsy,lymph node road mapping,identification of the vascular system round the major vessels,and the detection of ureters in order to reduce the risk of iatrogenic ureteral lesions in colorectal surgery.

关键词： Fluorescence Enhanced reality Anastomotic leak Lymph node Anastomosis

Natural maternal transmission of H pylori in Mongolian gerbils

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World Journal of Gastroenterology 2006年第35期12卷 5663-5667页

作者： Jin-uk Lee Okjin Kim Department of Laboratory Animal Sciences College of Medicine Seoul National University Seoul 110-799 South Korea Animal Disease Research Unit College of Life Science and Natural Resources Wonkwang University Iksan 570-749 South Korea

AIM: To investigate maternal H pylori infection status to determine the potential of maternal transmission. METHODS: In the present study, we examined these issues in an experimental murine model, which is a Mongolian gerbil model that has been reported as an optimal laboratory animal model to study H pylori . Pregnant Mongolian gerbils, infected experimentally with H pylori, were divided into as four groups. Following the experimental design, the stomachs of the mother and litters were isolated and assessed for transmission of H pylori at the prenatal period, parturition day, 1-wk old and 3-wk old respectively. Bacterial culture and polymerase chain reaction (PCR) were used to examine the presence of transmitted H pylori. RESULTS: All litters showed no transmission of H pylori during pregnancy and at parturition day. However, they revealed 33.3% and 69.6% at 1-wk and 3-wk of age respectively by PCR. CONCLUSION: These results suggested that vertical infection during the prenatal period or delivery procedure is unlikely as a route of mother-to-child H pylori infection. It may be that H pylori is acquired through breast- feeding, contaminated saliva and fecal-oral transmission during co-habitation.

关键词： H pylori Vertical Maternal Transmission

VLES Modelling with the Renormalization Group

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Journal of Thermal Science 2003年第4期12卷 328-331页

作者： Chris De Langhe rug.ac.be Bart Merci rug.ac.be Koen Lodefier rug.ac.be Erik Dick rug.ac.be Ghent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent Belgium

In a Very-Large-Eddy Simulation (VLES), the filterwidth-wavenumber can be outside the inertial range, and simple subgrid models have to be replaced by more complicated (''RANS-like'') models which can describe the transport of the biggest eddies. One could approach this by using a RANS model in these regions, and modify the lengthscale in the model for the LES-regions. The problem with these approaches is that these models are specifically calibrated for RANS computations, and therefore not suitable to describe inertial range quantities. We investigated the construction of subgfid viscosity and transport equations without any calibrated constants, but these are calculated directly form the Navier-Stokes equation by means of a Renormalization Group (RG) procedure. This leads to filterwidth dependent transport equations and effective viscosity with the right limiting behaviour (DNS and RANS limits).

关键词： very-large-eddy simulation subgrid modellig k-εmodel.