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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)

Comparative Study of Light Manipulation in Three-Level Systems Via Spontaneously Generated Coherence and Relative Phase of Laser Fields

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Communications in Theoretical Physics 2019年第8期71卷 947-954页

作者： Nguyen Huy Bang Le Nguyen mai anh Nguyen Tien Dung Le Van Doai Vinh University 182 Le Duan Street Vinh City Vietnam Nong Lam University Ho Chi Minh City Vietnam (Received March 21 2019revised manuscript

We present a comparative study of the control of group velocity in three-level atomic systems including Λ-, Ladder-, and V-types via spontaneously generated coherence(SGC) and relative phase of laser *** the steady regime, expressions of group index are derived as an analytical function of controllable parameters related to SGC and relative *** is shown that the group velocity can be further slowed down or speeded up under SGC in which modifications of group velocity due to the SGC in Λ-and V-systems are stronger than that in *** particular, when interference strength of SGC p increases from 0.7 to 1.0, the light propagation is switched from superluminal to subluminal modes(for Λ-and Ladder-systems) or from subluminal to superluminal modes(for Vsystem).In the presence of relative phase, the group velocity changes between subluminal and superluminal modes with a period of 2π.In resonant region, the largest positive value of group index reaches at the relative phase φ=π while the largest negative value of group index reaches at φ= 0 and 2π for the Λ-and Ladder-systems, otherwise, for the V-system the largest positive group index occurs at φ= 0 and 2π, and the largest negative group index occurs at φ=π.

关键词： electromagnetically induced transparency spontaneously generated coherence group velocity

Adaptive data fusion framework for modeling of non-uniform aerodynamic data

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Chinese Journal of Aeronautics 2023年第7期36卷 316-336页

作者： Vinh PHAM Maxim TYAN tuan anh NGUYEN Chi-Ho LEE L.V.Thang NGUYEN Jae-Woo LEE Department of Aerospace Information Engineering Konkuk UniversitySeoul 05029Republic of Korea Konkuk Aerospace Design-Airworthiness Institute Konkuk UniversitySeoul 05029Republic of Korea

Multi-fidelity Data Fusion(MDF)frameworks have emerged as a prominent approach to producing economical but accurate surrogate models for aerodynamic data modeling by integrating data with different fidelity ***,most existing MDF frameworks assume a uniform data structure between sampling data sources;thus,producing an accurate solution at the required level,for cases of non-uniform data structures is *** address this challenge,an Adaptive Multi-fidelity Data Fusion(AMDF)framework is proposed to produce a composite surrogate model which can efficiently model multi-fidelity data featuring non-uniform ***,the design space of the input data with non-uniform data structures is decomposed into subdomains containing simplified ***,different MDF frameworks and a rule-based selection process are adopted to construct multiple local models for the subdomain *** the other hand,the Enhanced Local Fidelity Modeling(ELFM)method is proposed to combine the generated local models into a unique and continuous global ***,the resulting model inherits the features of local models and approximates a complete database for the whole design *** validation of the proposed framework is performed to demonstrate its approximation capabilities in(A)four multi-dimensional analytical problems and(B)a practical engineering case study of constructing an F16C fighter aircraft’s aerodynamic *** comparisons of the generated models using the proposed AMDF framework and conventional MDF approaches using a single global modeling algorithm are performed to reveal the adaptability of the proposed approach for fusing multi-fidelity data featuring non-uniform ***,the results indicated that the proposed framework outperforms the state-of-the-art MDF approach in the cases of non-uniform data.

关键词： Aerodynamic modeling Data fusion Diverse data structure Multi-fidelity data Multi-fidelity surrogate modeling

A Neural-network-based Approach to Study the Energy-optimal Hovering Wing Kinematics of a Bionic Hawkmoth Model

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Journal of Bionic Engineering 2019年第5期16卷 904-915页

作者： anh tuan Nguyen Ngoc Doan Tran Thanh Trung Vu Thanh Dong Pham Quoc Tru Vu Jae-Hung Han Faculty of Aerospace Engineering Le Quy Don Technical University236 Hoang Quoc VietVietnam Office of International Cooperation Le Quy Don Technical University236 Hoang Quoc VietVietnam Department ofAerospace Engineerings Korea Advanced Institute of Science and Technology Daejeon 34141Republic ofKorea

This paper presents the application of an artificial neural network to develop an approach to determine and study the energy-optimal wing kinematics of a hovering bionic hawkmoth model.A three-layered artificial neural network is used for the rapid prediction of the unsteady aerodynamic force acting on the wings and the required *** this artificial network is integrated into genetic and simplex algorithms,the running time of the optimization process is reduced *** validity of this new approach is confirmed in a comparison with a conventional method using an aerodynamic model based on an extended unsteady vortex-lattice method for a sinu soidal wing kinematics *** studying the obtained results,it is found that actual hawkmoths do not hover under an energy-optimal ***,by tilting the stroke plane and lowering the wing positions,they can compromise and expend some energy to enhance their maneuverability and the stability of their flight.

关键词： optimal hovering wing kinematics artificial neural network insect flight genetic algorithm unsteady vortex-lattice method bionics

Antibiofilm activity of a-mangostin extracted from Garcinia mangostana L. against Staphylococcus aureus

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Asian Pacific Journal of Tropical Medicine 2017年第12期10卷 1154-1160页

作者： Nguyen Thi mai Phuong Ngo Van Quang Ta Thu mai Nguyen Vu anh Chutima Kuhakarn Vichai Reutrakul Albert Bolhuis Institute of Biotechnology Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadHanoiViet Nam Graduate University of Science and Technology Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadHanoiViet Nam Institute of Chemistry Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadHanoiViet Nam Center of Excellence for Innovation in Chemistry and Department of Chemistry Faculty of ScienceMahidol UniversityRama 6 RoadBangkok 10400Thailand Department of Pharmacy and Pharmacology University of BathClaverton Down BathBA2 7AYBathUK

Objective: To isolate a-mangostin(AMG) from the peels of mangosteen(Garcinia mangostana L.), grown in Vietnam, and to investigate antibiofilm activity of this compound against three Staphylococcus aureus(S. aureus) strains, one of which was methicillin-resistant S. aureus(MRSA) and the other two strains were methicillinsensitive S. aureus(MSSA).Methods: AMG in n-hexane fraction was isolated on a silica gel column and chemically analyzed by HPLC and NMR. The antibiofilm activity of this compound was investigated by using a 96-well plate model for the formation of biofilms. Biofilm biomass was quantified using crystal violet. The viability of cells was observed under confocal microscopy using LIVE/DEAD Bac Light stains. Biofilm composition was determined using specific chemical and enzyme tests for polysaccharide, protein and DNA. Membranedamaging activity was assayed by measuring the hemolysis of human red blood cells in presence of ***: The results indicated that the isolated AMG, with a purity that exceeded 98%,had minimal inhibitory concentrations in the range of 4.6–9.2 mmol/L for the three strains tested. Interestingly, the MSSA strains were more sensitive to AMG than the MRSA strain. Minimal bactericidal concentrations were 2-fold higher than the minimal inhibitory concentration values for the three strains, indicating that AMG was a bactericidal compound. AMG also prevented biofilm formation effectively, albeit that again the MRSA strain was the most resistant. Interestingly, biofilms of the MRSA strain contained protein as a main component of the extracellular matrix, whereas this was polysaccharide in the MSSA strains. This might relate to the resistance of the MRSA 252 strain to *** using human red blood cells indicated that AMG caused significant membrane damage with 50% of cell lysis occurred at concentration of about 36 mmol/***: Our results provide evidence that the isolated AMG has inhibitory activity against biofilm formation

关键词： α-Mangostin Garcinia mangostana Biofilms Methicillin resistance Staphylococcus aureus

Examining unobserved factors associated with red light running in Vietnam:A latent class model analysis

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Transportation Safety and Environment 2022年第1期4卷 110-122页

作者： Tien Dung Chu Tomio Miwa tuan anh Bui Quang Phuc Nguyen Quang Huy Vu Department of Highway and Traffic Engineering University of Transport and CommunicationsNo.3 Cau Giay StreetLang Thuong WardDong Da DistrictHanoi 10001Vietnam Institute of Materials and Systems for Sustainability Nagoya UniversityFuro-choChikusa-kuNagoya cityAichi Prefecture464-8603Japan

Red-light running(RLR)is a crucial violation that causes traffic accidents and *** factors that affect RLR is very significant to reduce the potential of this *** studies have paid considerable attention to the observable factors,but not to unobservable *** study aims to examine the effects of observable and unobservable factors on *** study uses a latent class model(LCM)to assign individuals into two classes—red-light-respectful and red-light-disrespectful road users—by surveying 751 respondents who use private transportation *** study incorporates psychological determinants into the LCM to account for unobservable *** contribution of this study is the in-depth investigation into law-respectful and law-disrespectful behaviours and intentional and unintentional *** a study has not yet been conducted in the existing *** addition,a comprehensive comparison of the LCM and a traditional ordered probit model was ***,the results suggest that the LCM is superior to the model that does not consider latent *** estimation results are in alignment with previous studies on RLR:males,younger drivers/riders,less educated road users and motorcyclists are more likely to run red *** analysis of the latent variables shows that surrounding conditions—the behaviour of other violators,the absence of traffic police,and long waiting times—increase the possibility of *** on these results,we provide suggestions to policymakers and traffic engineers:the implementation of enforcement cameras and penalties for violators are critical countermeasures to minimize the potential of RLR.

关键词： red light running(RLR) developing country latent class model(LCM) multiple indicator multiple cause(MIMIC)model latent variables(LVs) motorcycles(MCs) traffic violation

Examining Modal Shift to Public Transport in Developing Asian Cities:A Case Study in Hanoi City,Vietnam

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Journal of Traffic and Transportation Engineering 2023年第4期11卷 179-191页

作者： Vu anh tuan Vietnamese-German Transport Research Centre Vietnamese-German UniversityBình Dương 75000Vietnam

Quite many Asian cities are facing the issues of motorcycle dominance,and to solve it these cities are developing urban mass rapid transit systems(i.e.,BRT and MRT)with an intention to attract a large number of motorcycle and car ***,there might be uncertainties in shifting private transport users to new public transport systems,thereby risking the effectiveness of the investment in public *** study aims to examine the possibilities of modal shift to public transport by exploring current patterns of people’s travel behavior and anticipating their mode choice changes under policy intervention *** City,a typical motorcycle-dominated city in Asia,is selected for a case study.A stated preference survey is conducted and SP/RP mode choice models are estimated for different segments of urban transport *** is revealed that a significant number of private transport users might still stick to motorcycle and car use despite aggressive improvements of public transport in the *** chaining behavior and presence of school kid(s)in the family may prevent family members from shifting to public transport.A longer travel distance may not necessarily lead to a higher modal shift away from *** findings would be helpful to guide policy making towards sustainable development of public transport systems and effective management of private transport in developing cities,especially whose motorcycles are rapidly increasing and being dominant.

关键词： Public transport BRT transportation management

Urban Accessibility in Motorcycle Dependent Cities - Case Study in Ho Chi Minh City, Vietnam

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Journal of Traffic and Transportation Engineering 2023年第2期11卷 74-94页

作者： Vu anh tuan Vietnamese-German Transport Research Centre Vietnamese-German UniversityBình Dương 75000Vietnam

Motorcycle dependent cities have specific characteristics in terms of urban accessibility.A rapid increase in the number of motorcycles and other private motorized modes make transport problems more serious and cause severe capacity problems for the infrastructure systems in these ***,it is necessary to optimize the development of different modes to meet travel demand and to ensure accessibility in all urban *** paper aims to explore accessibility conditions in Ho Chi Minh City,a typical motorcycle dependent city in *** of accessibility could be the key element for urban planning in Ho Chi Minh City in particular and motorcycle dependent cities in ***,management measures for motorcycles and competitive modes will be proposed to improve the accessibility conditions and thus support sustainable urban transport development for motorcycle dependent cities.

关键词： Motorcycle dependent cities accessibility traffic management measures

Likelihood of Innovative Construction Techniques to Build Disaster Resilience for Vernacular Housing in the Highland of Central Vietnam

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Journal of Civil Engineering and Architecture 2012年第10期6卷 1392-1398页

作者： Tran tuan anh School of Architecture and Design RMIT University Melbourne 3001 Australia Faculty of Architecture College of Sciences Hue University Hue 8454 Vietnam

Disaster mitigation for marginal communities has become one of the most significant development goals of the 21st century. Vietnam has been reported one of the five most vulnerable nations in the world to climate change and so serves as a useful case study in developing appropriate housing solutions after disasters. In addition, some local communities in remote mountainous areas of Vietnam still keep strong vernacular traditions in their housing, especially the typical timber house-on-stilt, which need intense consideration before employing any new techniques of disaster mitigation on them. Perceptions on how to develop a sustainable housing solution for such communities, therefore, is still controversial with very few useful options developed to date. The paper investigates the existing unsafe conditions of traditional houses of a local community in the central highland of Vietnam, exposed to natural disasters, together with an identification of several traditional features of this housing that would be needed to preserve in future construction. Some important gaps of these traditional houses in terms of disaster risk reduction are then displayed to show opportunities where new construction techniques have a high possibility to perform against extreme climate events.

关键词： Disaster vernacular housing housing design housing reconstruction

Study on Using Biological Sludge from Vinh Loc Industrial Park to Produce Composting Product

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Journal of Environmental Science and Engineering(A) 2018年第5期7卷 201-206页

作者： Ton That Lang Nguyen Thi mai Thao Pham Vu Nhat Uyen Dang anh tuan Environmental Department University of Natural Resources and EnvironmentHo Chi Minh City 00848Vietnam Microbiology Department University of TechnologyHo Chi Minh City 00848Vietnam

In order to examine the optimal design and operating parameters in composting of waste activated sludge,a series of experiments were conducted to discuss the optimal operating parameters for aerobic composting of waste activated sludge obtained from Vinh Loc Industrial Park that is located in Ho Chi Minh *** study was done by optimizing the ratios of sludge/inactive fillers and sludge/microbial products to improve the composting *** 50 days of composting,the composts of all experiment batches met the microorganism-organic fertilizer standards of 10 TCN 526:*** study indicated that the highest efficiency decomposition was obtained at the ratio of a sludge/inactive fillers of 1/0.1 and sludge/microbial products of 1/0.05:TOC(Total Organic Carbon)reduced by 20.2%,loss of Nitrogen was trivial(0.53%),the highest temperature reached at 55.5 oC and lasting for 5 days which ensures elimination of ***,the addition of nitrogen compounds during the composting is necessary to ensure the compost product can meet the nitrogen standard of microorganism-organic fertilizer.

关键词： Biological sludge microorganism-organic fertilizer aerobic composting reuse of sludge inactive fillers