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Applied Mathematics and Mechanics(English Edition) 2021年第5期42卷 721-746页

作者： A.T.tran H.LE qUANG q.C.HE D.H.NGUYEN Research and Application Center for Technology in Civil Engineering University of Transport and CommunicationsHanoi 10000Vietnam Laboratoire Modelisation et Simulation Multi-Echelle Unite Mixte de Recherche 8208Centre National de la Recherche ScientifiqueUniversite Gustave EiffelMarne-la-Vallee F-77454France School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China

The present work is concerned with a two-dimensional(2D)Stokes flow through a channel bounded by two parallel solid *** distance between the walls may be arbitrary,and the surface of one of the walls can be arbitrarily *** main objective of this work consists in homogenizing the heterogeneous interface between the rough wall and fluid so as to obtain an equivalent smooth slippery fluid/solid interface characterized by an effective slip *** solve the corresponding problem,two efficient numerical approaches are elaborated on the basis of the method of fundamental solution(MFS)and the boundary element methods(BEMs).They are applied to different cases where the fluid/solid interface is periodically or randomly *** results obtained by the proposed two methods are compared with those given by the finite element method and some relevant ones reported in the *** comparison shows that the two proposed methods are particularly efficient and accurate.

关键词： effective slip length method of fundamental solution(MFS) boundary element method(BEM) Stokeslet micro-channel fluid/solid interface

Radiative decays D*(s)→ D(s)γ in covariant confined quark model

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Chinese Physics C 2024年第2期48卷 45-56页

作者： C.T.tran M.A.Ivanov P.Santorelli q.C.Vo Department of Physics HCMC University of Technology and EducationVo Van Ngan 1700000 Ho Chi Minh CityVietnam Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research141980 DubnaRussia Dipartimento di Fisica"E.Pancini" Universitàdi Napoli Federico ⅡComplesso Universitario di Monte S.AngeloVia CintiaEdificio 680126 NapoliItaly Istituto Nazionale di Fisica Nucleare Sezione di Napoli80126 NapoliItaly University of Science 700000 Ho Chi Minh CityVietnam

Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢ*** radiative couplings gD*Dγencoding nonperturbative qCD effects are calculated in the framework of the covariant confined quark model developed by *** compare our results with other theoretical studies and experimental *** couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice qCD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or qCD sum rules.

关键词： covariant quark model radiative decay charmed meson

An improved CRNN for Vietnamese Identity Card Information Recognition

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Computer Systems Science & Engineering 2022年第2期40卷 539-555页

作者： Trinh Tan dat Le tran Anh Dang Nguyen Nhat Truong Pham Cung Le Thien Vu Vu Ngoc Thanh Sang Pham Thi Vuong Pham The Bao Information Science Faculty Sai Gon UniversityHCM City700000Vietnam Faculty of Electrical&Electronics Engineering University of TechnologyHCM City700000Vietnam

This paper proposes an enhancement of an automatic text recognition system for extracting information from the front side of the Vietnamese citizen identity(CID)***,we apply Mask-RCNN to segment and align the CID card from the ***,we present two approaches to detect the CID card’s text lines using traditional image processing techniques compared to the EAST ***,we introduce a new end-to-end Convolutional Recurrent Neural Network(CRNN)model based on a combination of Connectionist Temporal Classification(CTC)and attention mechanism for Vietnamese text recognition by jointly train the CTC and attention objective functions *** length of the CTC’s output label sequence is applied to the attention-based decoder prediction to make the final label *** process helps to decrease irregular alignments and speed up the label sequence estimation during training and inference,instead of only relying on a data-driven attention-based encoder-decoder to estimate the label sequence in long *** may directly learn the proposed model from a sequence of words without detailed *** evaluate the proposed system using a real collected Vietnamese CID card dataset and find that our method provides a 4.28%in WER and outperforms the common techniques.

关键词： Vietnamese text recognition OCR CRNN BLSTM attention mechanism joint CTC-Attention

Anti-inflammatory effects of alkaloid enriched extract from roots of Eurycoma longifolia Jack

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Asian Pacific Journal of Tropical Biomedicine 2019年第1期9卷 18-23页

作者： Dao Thi Thanh Hien tran Phi Long tran Phuong Thao Jeong-Hyung Lee Duong Thu trang Nguyen Thi Thu Minh Pham Van Cuong Do Thi Ngoc Lan Nguyen Hai Dang Nguyen Tien dat Deparment of Traditional Pharmacy Hanoi University of Pharmacy Department of Biochemistry College of Natural Sciences Kangwon National University Advanced Center for Bio-organic Chemistry Institute of Marine Biochemistry Vietnam Academy of Science and Technology National Institute of Drug quality Control Center for Research and Technology transfers

Objective: To examine the in vitro and in vivo anti-inflammatory effects of the alkaloid enriched extract(ELA) from the roots of Eurycoma longifolia. Methods: The in vitro antiinflammatory effects of ELA were evaluated by examining its inhibitory activities against nitric oxide(NO) production and inducible nitric oxide synthase(iN OS) and cyclooxygenase2(COX-2) expressions in lipopolysaccharide(LPS)-stimulated RAW264.7 cells. The level of NO produced in the culture media was determined by Griess method. The i NOS and COX-2 protein expressions were analyzed by Western blot. The in vivo effect of ELA was evaluated on LPS-induced septic shock in mice model. Mice mortality was monitored for5 days after injection of LPS. The chemical contents of the ELA were determined by using various chromatographic and spectroscopic techniques. Results: The ELA was found to exhibit a significant anti-inflammatory effect in both in vitro and in vivo models. The results demonstrated that ELA dose-dependently inhibited LPS-induced NO production as well as the protein iN OS and COX-2 expressions. In the septic shock model, ELA dose-dependently protected mice from LPS-induced mortality. Further study on the isolated components of ELA indicated that 9,10-dimethoxycanthin-6-one may contribute significantly to the antiinflammatory effects of the extract. Conclusions: These results suggest that ELA exhibits the anti-inflammatory activity via suppression of pro-inflammatory mediators such as NO, iN OS,and COX-2 and protects mice from LPS-induced mortality in septic shock model.

关键词： Eurycoma longifolia Anti-inflammation Alkaloid 9,10-dimethoxycanthin-6-one

APPLICATIONS OF NUMERICAL MODELLING FOR THE STUDY ON STORM SURGE IN TYPHOON XANGSANE IN THE CENTRAL COAST OF VIETNAM

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Tropical Cyclone Research and Review 2018年第3期7卷 179-192页

作者： THO dat tran DUC TRUONG DINH qUANG TRI DOAN qUANG TIEN tran The National Economics University Vietnam Sustainable Management of Natural Resources and Environment Research Group Faculty of Environment and Labour SafetyTon Duc Thang University National Center for Hydrometeorological Forecasting

Understanding impacts of typhoons due to storm surge plays an important role in reducing damage in coastal *** study used the SWAN wave model to simulate the typhoon waves and the SuWAT model to simulate storm surge and inundation caused by Typhoon Xangsane in 2006 which landed in the Central Coast of Vietnam from Nghe An to Phu Yen *** wind-pressure f ield was calculated by the Fujita’s model and reanalysis data were inputted to the SWAN and SuWAT *** simulated results of the typhoon wave showed that Typhoon Xangsane caused 5-7 m height waves in the coastal areas with a radius of 600 *** results of the storm surge combined with the simulations of wind,pressure,wave,and tide in the coastal areas were estimated at 2 *** simulated and calculated results of storm surge and inundation maps will help the decision makers in the Committee for Natural Disaster Prevention and Control to reduce the impacts of natural disasters induced to storm surge in the near future.

关键词： Typhoon Xangsane storm surge SWAN SuWAT

Vibration characteristics of piezoelectric functionally graded carbon nanotube-reinforced composite doubly-curved shells

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Applied Mathematics and Mechanics(English Edition) 2021年第6期42卷 819-840页

作者： V.V.THAM H.q.tranT T.M.TU National Univensity of Ciwil Engineering Giai Phong Road 55Hai Ba Trung DistrictHanoi 100000 Vietnam

This paper presents an analytical solution for the free vibration behavior of functionally graded carbon nanotube-reinforced composite(FG-CNTRC) doubly curved shallow shells with integrated piezoelectric layers. Here, the linear distribution of electric potential across the thickness of the piezoelectric layer and five different types of carbon nanotube(CNT) distributions through the thickness direction are considered. Based on the four-variable shear deformation refined shell theory, governing equations are obtained by applying Hamilton's principle. Navier's solution for the shell panels with the simply supported boundary condition at all four edges is derived. Several numerical examples validate the accuracy of the presented solution. New parametric studies regarding the effects of different material properties, shell geometric parameters, and electrical boundary conditions on the free vibration responses of the hybrid panels are investigated and discussed in detail.

关键词： free vibration four-variable shear deformation refined theory functionally graded carbon nanotube-reinforced composite(FG-CNTRC) piezoelectric material

GLOBAL BOUND ON THE GRADIENT OF SOLUTIONS TO p-LAPLACE TYPE EqUATIONS WITH MIXED datA

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Acta Mathematica Scientia 2024年第4期44卷 1394-1414页

作者： Minh-Phuong tran The-quang tran Thanh-Nhan NGUYEN Applied Analysis Research Group Faculty of Mathematics and StatisticsTon Duc Thang UniversityHo Chi Minh CityVietnam Nguyen Huu Huan High School Thu Duc CityVietnam Group of Analysis and Applied Mathematics Department of MathematicsHo Chi Minh City University of EducationVietnam

In this paper,the study of gradient regularity for solutions of a class of elliptic problems of p-Laplace type is *** particular,we prove a global result concerning Lorentz-Morrey regularity of the non-homogeneous boundary data problem:-div((s^(2)+|▽u|^(2)p-2/2)▽u)=-div(|f|^(p-2)f)+g inΩ,u=h in■Ω,with the(sub-elliptic)degeneracy condition s∈[0,1]and with mixed data f∈L^(p)(q;R^(n)),g∈Lp/(p-1)(Ω;R^(n))for p∈(1,n).This problem naturally arises in various applications such as dynamics of non-Newtonian fluid theory,electro-rheology,radiation of heat,plastic moulding and many *** on the idea of level-set inequality on fractional maximal distribution functions,it enables us to carry out a global regularity result of the solution via fractional maximal *** to the significance of M_(α)and its relation with Riesz potential,estimates via fractional maximal functions allow us to bound oscillations not only for solution but also its fractional derivatives of orderα.Our approach therefore has its own interest.

关键词： gradient estimates p-Laplace quasilinear elliptic equation fractional maximal operators Lorentz-Morrey spaces

Random vibration analysis of FGM plates subjected to moving load using a refined stochastic finite element method

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Defence Technology（防务技术） 2024年第4期34卷 42-56页

作者： Ngoc-Tu Do Trung Thanh tran Faculty of Mechanical Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiViet Nam

The article introduces a finite element procedure using the bilinear quadrilateral element or four-node rectangular element(namely q4 element) based on a refined first-order shear deformation theory(rFSDT) and Monte Carlo simulation(MCS), so-called refined stochastic finite element method to investigate the random vibration of functionally graded material(FGM) plates subjected to the moving *** advantage of the proposed method is to use r-FSDT to improve the accuracy of classical FSDT, satisfy the stress-free condition at the plate boundaries, and combine with MCS to analyze the vibration of the FGM plate when the parameter inputs are random quantities following a normal distribution. The obtained results show that the distribution characteristics of the vibration response of the FGM plate depend on the standard deviation of the input parameters and the velocity of the moving ***, the numerical results in this study are expected to contribute to improving the understanding of FGM plates subjected to moving loads with uncertain input parameters.

关键词： FGM Moving load R-FSDT q4 element Monte Carlo simulation Random vibration

Intermediary RRT*-PSO:A Multi-Directional Hybrid Fast Convergence Sampling-Based Path Planning Algorithm

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Computers, Materials & Continua 2023年第8期76卷 2281-2300页

作者： Loc q.Huynh Ly V.tran Phuc N.K.Phan Zhiqiu Yu Son V.T.Dao School of Industrial Engineering and Management International UniversityVietnam National University HCMCHo Chi Minh City700000Vietnam Department of Industrial Management National Taiwan University of Science and TechnologyTaipei City106335Taiwan

Path planning is a prevalent process that helps mobile robots find the most efficient pathway from the starting position to the goal position to avoid collisions with *** this paper,we propose a novel path planning algorithm-Intermediary RRT*-PSO-by utilizing the exploring speed advantages of Rapidly exploring Random Trees and using its solution to feed to a metaheuristic-based optimizer,Particle swarm optimization(PSO),for fine-tuning and *** Phase 1,the start and goal trees are initialized at the starting and goal positions,respectively,and the intermediary tree is initialized at a random unexplored region of the search *** trees were grown until one met the other and then merged and re-initialized in other unexplored *** the start and goal trees merge,the first solution is found and passed through a minimization process to reduce unnecessary *** 2 begins by feeding the minimized solution from Phase 1 as the global best particle of PSO to optimize the *** simulating two special benchmark configurations and six practice configurations with special cases,the results of the study concluded that the proposed method is capable of handling small to large,simple to complex continuous environments,whereas it was very tedious for the previous method to achieve.

关键词： Motion planning global path planning rapidly exploring random trees particle swarm optimization

Nonlinear dynamic analysis of functionally graded carbon nanotube-reinforced composite plates using MISq20 element

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Frontiers of Structural and Civil Engineering 2023年第7期17卷 1072-1085页

作者： quoc-Hoa PHAM Trung Thanh tran Phu-Cuong NGUYEN Advanced Structural Engineering Laboratory Department of Structural EngineeringFaculty of Civil EngineeringHo Chi Minh City Open UniversityHo Chi Minh City 700000Vietnam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoi 100000Vietnam

The main objective of this study is to further extend the mixed integration smoothed quadrilateral element with 20 unknowns of displacement(MISq20)to investigate the nonlinear dynamic responses of functionally graded carbon nanotube-reinforced composite(FG-CNTRC)plates with four types of carbon nanotube *** smooth finite element method is used to enhance the accuracy of the q4 element and avoid shear locking without using any shear correction *** method yields accurate results even if the element exhibits a concave quadrilateral shape and reduces the error when the element meshing is ***,the element stiffness matrix is established by integrating the boundary of the smoothing *** motion equation of the FG-CNTRC plates is solved by adapting the Newmark method combined with the Newton–Raphson ***,the calculation program is coded in the MATLAB software and verified by comparing it with other published ***,the effects of the input parameters on the nonlinear vibration of the plates are investigated.

关键词： carbon nanotube MISq20 FG-CNTRC plate nonlinear vibration nonlinear dynamic analysis SFEM