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A Sub-Grid Structure Enhanced Discontinuous Galerkin Method for Multiscale Diffusion and Convection-Diffusion Problems

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Communications in Computational Physics 2013年第7期14卷 370-392页

作者： eric t.chung Wing tat Leung Department of Mathematics The Chinese University of Hong KongHong Kong

In this paper,we present an efficient computational methodology for diffusion and convection-diffusion problems in highly heterogeneous media as well as convection-dominated diffusion *** is well known that the numerical computation for these problems requires a significant amount of computermemory and ***,the solutions to these problems typically contain a coarse component,which is usually the quantity of interest and can be represented with a small number of degrees of *** are many methods that aim at the computation of the coarse component without resolving the full details of the *** proposed method falls into the framework of interior penalty discontinuous Galerkin method,which is proved to be an effective and accurate class of methods for numerical solutions of partial differential equations.A distinctive feature of our method is that the solution space contains two components,namely a coarse space that gives a polynomial approximation to the coarse component in the traditional way and a multiscale space which contains sub-grid structures of the solution and is essential to the computation of the coarse *** addition,stability of the method is *** numerical results indicate that the method can accurately capture the coarse behavior of the solution for problems in highly heterogeneous media as well as boundary and internal layers for convection-dominated problems.

关键词： Multiscale problem sub-grid capturing multiscale basis function boundary layer internal layer

Efficient Simulation of Wave Propagation with Implicit Finite Difference Schemes

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Numerical Mathematics(theory,Methods and Applications) 2012年第2期5卷 205-228页

作者： Wensheng Zhang Li tong eric t.chung LSEC Institute of Computational Mathematics and Scientific/Engineering ComputingAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing P.O.Box 2719100190 China Department of Mathematics The Chinese University of Hong KongHong Kong

Finite difference method is an important methodology in the approximation of *** this paper,we will study two implicit finite difference schemes for the simulation of *** are the weighted alternating direction implicit(ADI)scheme and the locally one-dimensional(LOD)*** approximation errors,stability conditions,and dispersion relations for both schemes are *** analysis shows that the LOD implicit scheme has less dispersion error than that of the ADI ***,the unconditional stability for both schemes with arbitrary spatial accuracy is established for the first *** order to improve computational efficiency,numerical algorithms based on message passing interface(MPI)are *** examples of wave propagation in a three-layer model and a standard complex model are *** analysis and comparisons show that both ADI and LOD schemes are able to efficiently and accurately simulate wave propagation in complex media.

关键词： Acoustic wave equation implicit schemes ADI LOD stability condition dispersion curve MPI parallel computations

A tV-Based Iterative Regularization Method for the Solutions of thermal Convection Problems

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Communications in Computational Physics 2013年第9期14卷 1120-1146页

作者： eric t.chung Jeff C.-F.Wong Department of Mathematics Lady Shaw BuildingThe Chinese University of Hong KongShatinHong Kong

Linear/nonlinear and Stokes based-stabilizations for the filter equations for damping out primitive variable(PV)solutions corrupted by uniformly distributed randomnoises are numerically studied through the natural convection(NC)aswell as the mixed convection(MC)*** most recognizable filter-scheme is based on a combination of the negative Laplace equation multiplied with the selection of the spatial scale and a linear function in order to preserve the uniqueness of the filtered solution.A more complicated filter-scheme,based on a Stokes problem which couples a filtered velocity and a filtered(artificial)pressure(or Lagrange multiplier)in order to enforce the incompressibility constraint,is also *** and Stokes basedfilters via nested iterative(NI)filters and the consistent splitting scheme(CSS)are proposed for the NC/MC *** by the total-variation(tV)model of image diffusion,well preserved feature flow patterns from the corrupted NC/MC environment are obtained by tV-Stokes based-filters together with the *** experimental results show that our proposed algorithms are effective and efficient in eliminating the unwanted spurious oscillations and preserving the accuracy of thermal convective fluid flows.

关键词： Linear/nonlinear differential filter Stokes differential filters Leray-alpha model total-variation regularization

Design,simulation,and testing of a tunable MEMS multi-threshold inertial switch

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Microsystems & Nanoengineering 2024年第2期10卷 37-46页

作者： Qiu Xu Rodrigo t.Rocha Yousef Algoos eric Feron Mohammad I.Younis Faculty of Electronic Information Engineering Huaiyin Institute of TechnologyHuai’an223003PR China Computer Electrical and Mathematical Science and Engineering DivisionKing Abdullah University of Science and TechnologyThuwal23955-6900Saudi Arabia Piezoelectric Microsystem technologies Silicon Austria LabsVillach9524Austria Physical Sciences and Engineering Division King Abdullah University of Science and TechnologyThuwal23955Saudi Arabia Mechanical Engineering Department State University of New YorkBinghamtonNY13902USA

this paper presents a tunable multi-threshold micro-electromechanical inertial switch with adjustable threshold *** demonstrated device combines the advantages of accelerometers in providing quantitative acceleration measurements and g-threshold switches in saving power when in the inactive state upon experiencing acceleration below the *** designed proof-of-concept device with two thresholds consists of a cantilever microbeam and two stationary electrodes placed at different positions in the sensing *** adjustable threshold capability and the effect of the shock duration on the threshold acceleration are analytically investigated using a nonlinear beam *** are shown for the relationships among the applied bias voltage,the duration of shock impact,and the tunable *** fabricated prototypes are tested using a shock-table *** analytical results agree with the experimental *** designed device concept is very promising for the classification of the shock and impact loads in transportation and healthcare applications.

关键词： tunable acceleration testing

Identification of the 2l2l′nl ″^(2)P^(0) Hollow Lithium Systems

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Chinese Physics Letters 1998年第5期15卷 332-334页

作者： Kwong t.chung GOU Bing-cong Department of Physics North Carolina State UniversityRaleighNC 27695-8202U.S.A Department of Applied Physics Beijing Institute of TechnologyBeijing 100081

In a recent letter[*** et al.,***.76,30(1996)],first experimental determination of the partial photoionization cross sections of lithium near the hollow atomic states was *** extensive R-matrix calculation has also been carried out for the 2l2l′nl ″^(2)P^(0) hollow states and assignments for the excited states have been ***,these assignments are substantially different from those of other theoretical *** points out the need for more information and discussion which are necessary for a meaningful comparison.

关键词： methods. assignment states

Commentaryon"Relationship between dietary niacin intake and erectile dysfunction:a population-based study"

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Asian Journal of Andrology 2024年第4期26卷 439-439页

作者： eric chung Department of Urology The University of QueenslandPrincess Alexandra HospitalBrisbaneQLD 4000Australia AndroUrology Centre BrisbaneQLD 4000Australia

the real benefits of vitamins and dietary supplementation on health outcomes have always been mired in controversy,and to date,contradictory studies continue to be published to highlight their benefits when downplaying possible adverse effects.!this recently published National Health and Nutrition Examination Survey(NHANES)database study population investigating the role of niacin on erectile function reported that higher niacin intake,specifically in the highest tertile,was associated with a decreased risk of erectile dysfunction(ED)compared to the lowest tertile,showing an odds ratio(OR)of 0.56(95%confidence interval[CI]:0.37-0.85)based on 863 participants with ED from a pool of 3184 adults.2 Further analysis of dose-response curves and interaction analyses found a negative correlation between dietary niacin intake and the risk of ED,suggesting that a higher dietary niacin intake is associated with areducedriskof ED.

关键词： benefits intake erectile

Applying Source Parameter Imaging (SPI) to Aeromagnetic Data to Estimate Depth to Magnetic Sources in the Mamfe Sedimentary Basin

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International Journal of Geosciences 2024年第1期15卷 1-11页

作者： eric N. Ndikum Charles t. tabod Department of Physics HTTC Bambili The University of Bamenda Bamenda Cameroon Department of Fundamental Sciences Higher Technical Teacher Training College (HTTTC) Bamenda Cameroon Department of Physics University of Yaoundé 1 Yaoundé Cameroon Department of Physics Faculty of Science The University of Bamenda Bamenda Cameroon

Aeromagnetic data over the Mamfe Basin have been processed. A regional magnetic gridded dataset was obtained from the total Magnetic Intensity (tMI) data grid using a 3 × 3 convolution (Hanning) filter to remove regional trends. Major similarities in magnetic field orientation and intensities were observed at identical locations on both the regional and tMI data grids. From the regional and tMI gridded datasets, the residual dataset was generated which represents the very shallow geological features of the basin. Processing this residual data grid using the Source Parameter Imaging (SPI) for magnetic depth suggests that the estimated depths to magnetic sources in the basin range from about 271 m to 3552 m. the highest depths are located in two main locations somewhere around the central portion of the study area which correspond to the area with positive magnetic susceptibilities, as well as the areas extending outwards across the eastern boundary of the study area. Shallow magnetic depths are prominent towards the NW portion of the basin and also correspond to areas of negative magnetic susceptibilities. the basin generally exhibits a variation in depth of magnetic sources with high, average and shallow depths. the presence of intrusive igneous rocks was also observed in this basin. this characteristic is a pointer to the existence of geologic resources of interest for exploration in the basin.

关键词： Mamfe Basin Aeromagnetic Data Source Parameter Imaging (SPI) Depth to Magnetic Sources

Immunoregulatory and Anti-cancer Activities of Combination treatment of Novel Four-Herb Formula and Doxorubicin in 4t1-Breast Cancer Bearing Mice

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Chinese Journal of Integrative Medicine 2024年第4期30卷 311-321页

作者： Lea Ling-Yu Kan Ben chung-Lap Chan Grace Gar-Lee Yue LI Pei-ting Sharon Sze-Man Hon HUANG Dan-qi Miranda Sin-Man tsang Clara Bik-San Lau Ping-chung Leung Chun-Kwok Wong Institute of Chinese Medicine The Chinese University of Hong KongHong Kong SARChina State Key Laboratory of Research on Bioactivities and Clinical Applications of Medicinal Plants The Chinese University of Hong KongHong KongChina Department of Chemical Pathology The Chinese University of Hong KongHong Kong SARChina China-Australia International Research Centre for Chinese Medicine School of Health and Biomedical SciencesSTEM CollegeRMIT UniversityBundooraVictoriaAustralia Li Dak Sum Yip Yio Chin R&D Centre for Chinese Medicine The Chinese University of Hong Kong SARHong KongChina

Objective to investigate the in vivo immunomodulatory and anti-tumor mechanisms of the combined treatment of novel Four-Herb formula(4HF)and doxorubicin in triple-negative breast cancer(tNBC).Methods Murine-derived triple-negative mammary carcinoma cell line,4t1 cells,was cultured and inoculated into mouse mammary ***-six mice were randomly assigned into 6 groups(n=11 in ench):naive,control,LD 4HF(low dose 4HF),HD 4HF(high dose 4HF),LD 4HF+D(low dose and doxorubicin),and D(doxorubicin).Apart from the naive group,each mouse received subcutaneous inoculation with 5×10^(5)4t1 cells resuspended in 100µL of normal saline in the mammary fat *** from the day of tumor cell inoculation,tumors were grown for 6 *** LD and HD groups received daily oral gavage of 658 and 2,630 mg/kg 4HF,*** LD 4HF+D group received daily oral gavage of 658 mg/kg 4HF and weekly intraperitoneal injection of doxorubicin(5 mg/kg).the D group received weekly intraperitoneal injections of doxorubicin(5 mg/kg).the treatment naive mice received daily oral gavage of 0.2 mL double distilled water and 0.1 mL normal saline via intraperitoneal injection once a *** control group received daily oral gavage of 0.2 mL double-distilled *** treatment period was 30 *** the end of treatment,mice organs were harvested to analyze immunological activities via immunophenotyping,gene and multiplex analysis,histological staining,and gut microbiota *** Mice treated with the combination of 4HF and doxorubicin resulted in significantly reduced tumor and spleen burdens(Ptered the hypoxia and overall immune lymphocyte landscape,and manipulated gut microbiota to favor the anti-tumor immunological ***,immunosuppressive genes,cytokines,and chemokines such as C-C motif chemokine 2 and interleukin-10 of tumors were significantly downregulated(Ption treatment demonstrated synergetic activities and was most effective

关键词： adjunctivetherapy breast cancer cytokines Chinese medicine tumor microenvironment

Identification of Secondary Metabolites in tunisian tilia platyphyllos *** MALDI-tOF and GC-MS

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Journal of Renewable Materials 2024年第4期12卷 827-842页

作者： Ayda Khadhri Mohamed Mendili Marwa Bannour-Scharinger eric Masson Antonio Pizzi University of El-Manar II Faculty of SciencesPlantSoilEnvironment Interactions LaboratoryCampus AcademiaTunis2092Tunisia LERMAB University of Lorraine27 Rue Philippe SeguinEpinal88000France

this study is the first to evaluate the phytochemical content and biological properties of tunisian *** Scop.A total of 23 compounds of essential oils were identified by gas chromatography-mass spectrometry(GC-MS)analysis of bracts and fruit *** results show that oxygenated monoterpenes were the dominant class of essential *** phenolic composition was investigated by matrix-assisted laser desorption/ionizationtime of flight(MALDI-tOF).the analysis showed that the chemical profiles of the ethanolic extracts of bracts and fruits are substantially *** highest polyphenol content was found in the ethanolic extracts of the fruits(7.65 mg gallic acid equivalents(GAE).g−1 on dry weight(DW).As for the antioxidant capacity,it was recorded in the essential oils of the fruits(IC_(50)=0.91 ***^(−1)).the results obtained showed that the antioxidant activity of the fruit essential oil was higher than that of the ethanol *** fruit essential oil was also found to have the highest reducing power(IC_(50)=0.67 ***^(−1)).In terms of iron-chelating power,fruit essential oil has the highest chelating power(IC_(50)=2.03 ***^(−1)).Compared to the ethanolic extract,the essential oil had the maximum antioxidant *** enzymatic activity of acetylcholinesterase(AChE)inhibition of the essential oil from *** bracts had the most potent inhibitory effect(IC_(50)=0.77 ***^(−1)),followed by the essential oil from the fruits(IC_(50)=0.95 ***^(−1)).the results suggest that *** can be used as a potential source of naturally occurring bioactive compounds and antioxidants.

关键词： t.platyphyllos antioxidant activity acetylcholinesterase inhibition essential oil MALDI-tOF GC-MS