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Polymeric Liquid Templating of Hierarchical Porous Films by Nanofibrillar Alginic Acid Assemblies

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Soft Nanoscience Letters 2014年第1期4卷 6-14页

作者： Thai-hoa Tran Sy-thang ho Thanh-Dinh Nguyen Department of Chemical Engineering Laval University Quebec Canada. Department of Chemistry College of Sciences Hue University Hue Vietnam Department of Chemistry Dong Thap University Dong Thap Vietnam

Hierarchical phases of the biomaterials can be used as template to transfer their intricate organization into biomimic inorganic solids. Herein, hierarchical mesoporous silica films with aligned pores have been templated by nanofibrillar alginic acid. An aqueous suspension of the alginic acid nanofibers was prepared by treating the brown seaweeds with sodium carbonate solution and subsequent precipitation in dilute hydrochloric acid. The alginic acid nanofibers of the organize into a hierarchical aligned phase in an acetic acid-sodium acetate buffer that was used to template silica-alginic acid composite films by evaporation induced self-assembly of alkoxysilane with nanofibrillar alginic acid. Calcination of the alginic acid template afforded hierarchical mesoporous silica glasses. Carbonization of the silica-alginic acid composites and subsequent etching the silica recovered mesoporous carbon supercapacitors.

关键词： Nanofibrillar Alginic Acid Hierarchial Organization Mesoporosity Silica Films Carbon Supercapacitors

Compensation of Zn substitution and secondary phase controls effective mass and weighted mobility in In and Ga co-doped ZnO material

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Journal of Materiomics 2021年第4期7卷 742-755页

作者： Oanh Kieu Truong Le Anh Tuan Thanh Pham Ngoc Kim Pham Trang Huyen Cao Pham Truong huu Nguyen Dung Van hoang Hanh Kieu Thi Ta Dai Cao Truong hoa Thi Lai Thuy Dieu Thi Ung Vinh Cao Tran thang Bach Phan aboratory of Advanced Materials University of ScienceHoChiMinh City700000Viet Nam Vietnam National University HoChiMinh City700000Viet Nam Faculty of Physics and Engineering Physics University of ScienceHoChiMinh City700000Viet Nam Faculty of Materials Science and Technology University of ScienceHoChiMinh City700000Viet Nam Center for Innovative Materials and Architectures(INOMAR) HoChiMinh CityViet Nam Institute of Materials Science Vietnam Academy of Science and TechnologyHanoi100000Viet Nam

Conductivity s and thermal conductivity k are directly related to carrier concentration while Seebeck coefficient S is inversely proportional to carrier ***,improving thermoelectric(TE)performance is ***,the first-time analysis of secondary phase-controlled TE performance in terms of density-of-state effective mass m*d,weighted mobility mw and quality factor B is discussed in ZnO *** results show that the secondary spinel phase Ga2O_(3)(ZnO)9 not only impacts on k but also on s and S at high temperature,while the effect of carrier concentration seem to be dominant at low *** the high-spinel-segregation sample,a compensation of dopant atoms from the spinel to substitutional sites in the ZnO matrix at high temperature leads to a low decreased rate of temperaturedependent m**** compensation process also induces a band sharpening,a small mw reduction,and a large B *** a result,In and Ga co-doped ZnO bulk with the highest spinel segregation achieves the greatest PF improvement by 112.8%,owing to enhanced Seebeck coefficient by 110%as compared to the good Zn-substitution sample.

关键词： Thermoelectrics In and Ga co-Doped ZnO Secondary phase Zn substitution DOS effective Mass Weighted mobility

LiMn_2O_4/CNTs and LiNi_(0.5)Mn_(1.5)O_4/CNTs Nanocomposites as High-Performance Cathode Materials for Lithium-Ion Batteries

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Acta Metallurgica Sinica(English Letters) 2015年第1期28卷 122-128页

作者： thang Van Le Ha Tran Nguyen Anh Tuan Luu Man Van Tran Phung Loan My Le Faculty of Materials Technology Ho Chi Minh University of Technology 268 Ly Thuong Kiet Ward 14 District 10 Ho Chi Minh City Vietnam Department of Physical Chemistry University of Science VNUHCM 227 Nguyen Van Cu Street District 5 Ho Chi Minh CityVietnam

The demand of higher energy density and higher power capacity of lithium（Li）-ion secondary batteries has led to the search for electrode materials whose capacities and performance are better than those available today. Carbon nanotubes（CNTs）, with their unique properties such as 1D tubular structure, high electrical and thermal conductivities, and extremely large surface area, have been used as materials to prepare cathodes for Li-ion batteries. The structure and morphology of CNTs were analyzed by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and transmission electron microscopy（TEM）. The functional groups on the purified CNT surface such as –COOH, –OH were characterized by Fourier Transform infrared spectroscopy. The electrode materials were fabricated from LiMn2O4（LMO）, doped spinel LiNi0.5Mn1.5O4, and purified CNTs via solid-state reaction. The structure and morphology of the electrode were characterized using XRD, SEM, and TEM. Finally, the efficiency of the electrode materials using CNTs was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy.

关键词： Nanocomposites Carbon nanotubes(CNTs) Spinel materials Lithium-ion batteries(LIBs)

Test Case Generation from UML-Diagrams Using Genetic Algorithm

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Computers, Materials & Continua 2021年第5期67卷 2321-2336页

作者： Rajesh Kumar Sahoo Morched Derbali houssem Jerbi Doan Van thang P.Pavan Kumar Sipra Sahoo Department of Computer Science&Engineering Ajay Binay Institute of TechnologyCuttack753014India Department of Information Technology Faculty of Computing and ITKing Abdulaziz UniversityJeddah21589Saudi Arabia Department of Industrial Engineering University of Ha’ilCollege of EngineeringHail2440Saudi Arabia Faculty of Information Technology Industrial University of Ho chi Minh City700000Vietnam Department of Computer Science and Engineering FSTIFHEHyderabad501203India Department of Computer Science and Engineering ITERSOA Deemed to be UniversityBhubaneswar751030India

Software testing has been attracting a lot of attention for effective software *** model driven approach,Unified Modelling Language(UML)is a conceptual modelling approach for obligations and other features of the system in a model-driven *** tools interpret these models into other software artifacts such as code,test data and *** generation of test cases permits the appropriate test data to be determined that have the aptitude to ascertain the *** paper focuses on optimizing the test data obtained from UML activity and state chart diagrams by using Basic Genetic Algorithm(BGA).For generating the test cases,both diagrams were converted into their corresponding intermediate graphical forms namely,Activity Diagram Graph(ADG)and State Chart Diagram Graph(SCDG).Then both graphs will be combined to form a single graph called,Activity State Chart Diagram Graph(ASCDG).Both graphs were then joined to create a single graph known as the Activity State Chart Diagram Graph(ASCDG).Next,the ASCDG will be optimized using BGA to generate the test data.A case study involving a withdrawal from the automated teller machine(ATM)of a bank was employed to demonstrate the *** approach successfully identified defects in various ATM functions such as messaging and operation.

关键词： Genetic algorithm generation of test data and optimization state-chart diagram activity diagram model-driven approach

*** human visual cortex responses to flickering light using functional near infrared spectroscopy and constrained ICA

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Journal of Innovative Optical Health Sciences 2014年第6期7卷 77-89页

作者： Nguyen Duc thang Vo Van Toi Le Giang Tran Nguyen Huynh Minh Tam Lan Anh Trinh Biomedical Engineering Department International University Vietnam National Universities HCMCVietnam University of Saskatchewan Canada Electronics Engineering Department Posts and Telecommunications Institute of Technology ho Chi Minh City Vietnam

The human visual sensitivity to the flickering light has been under investigation for *** finding of research in this area can contribute to the understanding of human visual system mechanism and visual disorders,and establishing diagnosis and treatment of *** aim of this study is to investigate the ffects of the flickering light to the visual cortex by monitoring the hemodynamic responses of the brain with the functional near infrared spectrosoopy(ENIRS)*** the acquired fNIRS signals are afected by physiological factors and measurement artifacts,constrained independent component analysis(eICA)was applied to extract the actual fNIRS responses from the obtained *** experimental results revealed significant changes(p<0.0001)of the hemodynamic responses of the visual *** the baseline when the flickering stimulation was *** the uses of cICA,the contrast to noise ratio(CNR),reflecting the contrast of hemodynamic concentration between rest and task,became *** indicated the improvement of the NIRS signals when the noise was *** subsequent studies,statistical analysis was used to infer the correlation between the NIRS signals and the visual *** found that there was a slight decrease of the oxygenated hemoglobin con-centration(about 5.69%)over four frequencies when the modulation ***,the variations of oxy and deoxy-hemoglobin were not statistically significant.

关键词： Papillometre visual stimulation functional near infrared spectroscopy constrained independent component analysis

Polygonal Finite Element for Two-Dimensional Lid-Driven Cavity Flow

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Computers, Materials & Continua 2022年第3期70卷 4217-4239页

作者： T.Vu-huu C.Le-Thanh H.Nguyen-Xuan M.Abdel-Wahab Faculty of Civil Engineering Vietnam Maritime University484 Lach Tray Str.Hai PhongVietnam Faculty of Civil Engineering and Electricity Ho Chi Minh City Open UniversityVietnam CIRTech Institute Ho ChiMinh City University of Technology(HUTECH)Ho Chi Minh CityVietnam Department of Architectural Engineering Sejong University209 NeungdongroGwangjinguSeoul05006Republic of Korea Soete Laboratory Faculty of Engineering and ArchitectureGhent UniversityTechnologiepark Zwijnaarde903B-9052ZwijnaardeBelgium

This paper investigates a polygonal finite element(PFE)to solve a two-dimensional(2D)incompressible steady fluid problem in a cavity *** is a well-known standard benchmark(i.e.,lid-driven cavity flow)-to evaluate the numerical methods in solving fluid problems controlled by the Navier-Stokes(N-S)equation *** approximation solutions provided in this research are based on our developed equal-order mixed PFE,called *** is an exciting development based on constructing the mixed scheme method of two equal-order discretisation spaces for both fluid pressure and velocity fields of flows and our proposed stabilisation *** this research,to handle the nonlinear problem of N-S,the Picard iteration scheme is *** proposed method’s performance and convergence are validated by several simulations coded by commercial software,i.e.,*** this research,the benchmark is executed with variousReynolds numbers up to the maximum Re=*** results then numerously compared to available sources in the literature.

关键词： Lid-driven cavity incompressible steady Navier-Stokes equations polygonal finite element method

Fabrication and Characterization of Multi-layer Heat Mirror with Photocatalytic Properties

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Chinese Physics Letters 2009年第11期26卷 152-155页

作者： Tran Le Tuan Tran huu Chi Nguyen Dac Ngoc Son Luu Minh Nam hoang Dinh Quan Nguyen Department of Applied Physics College of Natural Science National University of He Chi Mirth City 227 Nguyen Van Cu District 5 Ward 4 He Chi Minh City Vietnam Department of Chemical Engineering College of Technology National University of He Chi Minh City 168 Ly Thuong Kiet District 10 Ho chi Minh City Vietnam

A novel TiO2（5）/TiO2（buffer）/Ti（4）/Ag（3）/Ti（2）/TiO2（1） multi-layer film coating with corning glass is designed and fabricated by a dc magnetron sputtering method as a renovation of the well-known TiO2/Ti/Ag/Ti/TiO2 system in order to obtain a heat mirror system with photocatalytic properties due to sufficient thickness of the Ti02 layer. The outer TiO2 layer is fabricated in two steps, possibly claimed as two layers TiO2（5） and TiO2（buuer）, among which TiO2（buffer） the 70-nm-thick layer deposited in poor oxygen effectively minimizes the oxidation toward its neighbor Ti（4） layer. The optimal total thickness of the TiO2（5） and TiO（buffer） di-layer is found to be 300nm to yield a highly photo-catalytic property of the film without affecting the optical properties considerably. This multi-layer film can transmit light of above 75-85% in the visible spectrum （380 ≤ λ≤ 760 nm） and reflect radiation of above 90% in the infrared spectrum （ λ≥760 nm）. Such multi-layer coatings are strongly recommended not only as promising transparent heat mirrors but also as photo-catalytic films for architectural window coatings.

关键词： Condensed matter: electrical magnetic and optical Surfaces interfaces and thin films Chemical physics and physical chemistry

Optical properties and dynamic process in metal ions doped on CdSe quantum dots sensitized solar cells

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Chinese Optics Letters 2018年第7期16卷 71-77页

作者： Ha Thanh Tung Dang huu Phuc Institute of Research and Development Duy Tan University Theoretical Physics Research Group Advanced Institute of Materials Science Ton Duc Thang University Faculty of Applied Sciences Ton Duc Thang University

In recent years, the nanostructure for solar cells have attracted considerable attention from scientists as a result of a promising candidate for low cost devices. In this work, quantum dots sensitized solar cells with effective performance based on a co-sensitized Cd S∕Cd Se：Mn2＋（or Cu2＋） nanocrystal, which was made by successive ionic layer absorption and reaction, are discussed. The optical, physical, chemical, and photovoltaic properties of quantum dots sensitized solar cells were sensitized to Mn2＋and Cu2＋dopants. Therefore, the short current（JSC）of the quantum dot sensitized solar cells is boosted dramatically from 12.351 mA∕cm2 for pure Cd Se nanoparticles to 18.990 mA∕cm2 for Mn2＋ions and 19.915 mA∕cm2 for Cu2＋ions. Actually, metal dopant extended the band gap of pure Cd Se nanoparticles, reduced recombination, enhanced the efficiency of devices, and improved the charge transfer and collection. In addition, Mn2＋and Cu2＋dopants rose to the level of the conduction band of pure Cd Se nanoparticles, which leads to the reduction of the charge recombination, enhances the lightharvesting efficiency, and improves the charge diffusion and collection. The results also were confirmed by the obtained experimental data of photoluminescence decay and electrochemical impedance spectroscopy.

关键词： CdS Cu Mn FTO Optical properties and dynamic process in metal ions doped on CdSe quantum dots sensitized solar cells

Stabilization for Equal-Order Polygonal Finite Element Method for High Fluid Velocity and Pressure Gradient

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Computers, Materials & Continua 2020年第3期62卷 1109-1123页

作者： T.Vu-huu C.Le-Thanh H.Nguyen-Xuan M.Abdel-Wahab Department of Electrical energy MetalsMechanical Constructions and SystemsFaculty of Engineering and ArchitectureGhent UniversityGhentBelgium Faculty of Civil Engineering Vietnam Maritime UniversityHai PhongVietnam Faculty of Civil Engineering and Electricity Ho Chi Minh City Open UniversityHo Chi MinhVietnam CIRTech Institute Ho Chi Minh City University of Technology(HUTECH)Ho Chi MinhVietnam Division of Computational Mechanics Ton Duc Thang UniversityHo Chi MinhVietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi MinhVietnam

This paper presents an adapted stabilisation method for the equal-order mixed scheme of finite elements on convex polygonal meshes to analyse the high velocity and pressure gradient of incompressible fluid flows that are governed by Stokes equations *** technique is constructed by a local pressure projection which is extremely simple,yet effective,to eliminate the poor or even non-convergence as well as the instability of equal-order mixed polygonal *** this research,some numerical examples of incompressible Stokes fluid flow that is coded and programmed by MATLAB will be presented to examine the effectiveness of the proposed stabilised method.

关键词： Polygonal finite element method fluid computation stokes equation mixed method local projection