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Circuits and Systems 2024年第1期15卷 1-11页

作者： nguyen Quang Tuan Faculty of Information Technology Nha Trang University Khanh Hoa Vietnam

The article synthesizes and presents the results regarding the stability of positive homogeneous systems that have been researched and published in recent years. Next, we provide a sufficient condition for global exponential stability in the case of discrete-time positive homogeneous systems with an order less than one with time-varying delays.

关键词： Exponential Stability Homogeneous Systems Positive Systems Positive Homogeneous Systems

STABILITY ANALYSIS OF A COMPUTER VIRUS PROPAGATION MODEL WITH ANTIDOTE IN VULNERABLE SYSTEM

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Acta Mathematica Scientia 2016年第1期36卷 49-61页

作者： nguyen Huu khanh nguyen Bich HUY Department of Mathematics College of Natural SciencesCan Tho University Departmet of Mathematics Ho Chi Minh University of Education

We study a proposed model describing the propagation of computer virus in the network with antidote in vulnerable system. Mathematical analysis shows that dynamics of the spread of computer viruses is determined by the threshold Ro. If Ro 〈 1, the virusfree equilibrium is globally asymptotically stable, and if R0 〉 1, the endemic equilibrium is globally asymptotically stable. Lyapunov functional method as well as geometric approach are used for proving the global stability of equilibria. A numerical investigation is carried out to confirm the analytical results. Through parameter analysis, some effective strategies for eliminating viruses are suggested.

关键词： computer virus virus-free equilibrium endemic equilibrium global stability antidote

Enhancing compressive strength and durability of self-compacting concrete modified with controlled-burnt sugarcane bagasse ash-blended cements

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Frontiers of Structural and Civil Engineering 2022年第2期16卷 161-174页

作者： Duc-Hien LE Yeong-Nain SHEEN khanh-Hung nguyen Sustainable Developments in Civil Engineering Research Group Faculty of Civil EngineeringTon Duc Thang UniversityHo Chi Minh City700000Vietnam Department of Civil Engineering Kaohsiung University of Science and TechnologyKaohsiung80778China Department of Civil Engineering Lac Hong UniversityBien Hoa810000Vietnam

In sugar industries,the growing amount of sugarcane bagasse ash(SBA),a byproduct released after burning bagasse for producing electricity,is currently causing environmental *** residual ash displays a pozzolanic potential;and hence,it has potential as a cement *** study focuses on enhancing suitability of SBA through incorporating ground blast furnace slag(BFS)in manufacturing self-compacting concretes(SCCs).For this purpose,SBA was processed by burning at 700°C for 1 h,before being ground to the cement fineness of 4010 cm2/*** mixtures were prepared by changing the proportions of SBA and BFS(i.e.,10%,20%,and 30%)in blended systems;and their performance was *** results showed that the presence of amorphous silica was detected for the processed SBA,revealing that the strength activity index was above 80%.The compressive strength of SCC containing SBA(without BFS)could reach 98%–127%of that of the control;combination of SBA and 30%BFS gets a similar strength to the control after 28 *** durability,the 10%SBA+30%BFS mix exhibited the lowest risk of ***,the joint use of SBA and BFS enhanced significantly the SCC’s sulfate ***,a hyperbolic formula for interpolating the compressive strength of the SBA-based SCC was proposed and validated with error range estimated within±10%.

关键词： sugarcane bagasse ash self-compacting concrete compressive strength sulfate resistance water absorption strength formula

Investigating the customer trust in artificial intelligence: The role of anthropomorphism, empathy response, and interaction

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CAAI Transactions on Intelligence Technology 2023年第1期8卷 260-273页

作者： nguyen Thi khanh Chi Nam Hoang Vu Foreign Trade University HanoiVietnam Faculty of International Economics Foreign Trade UniversityHanoiVietnam

Artificial intelligence(AI)applications are observed in different industries including the services,where the impressive changing pace is boosted by the technological advances in *** use of AI in the daily work of individuals and in shaping the relationship between firms and customers has resulted in increased efficiency and a higher degree of fascination in *** are,however,customers'fears related to the use of ***,understanding how AI affects customer trust is worth *** study focuses on the AI applications and their impact on communication quality and customer *** features of AI applications investigated in this study include anthropomorphism,empathy response and interaction.A model was first empirically validated through Confirmatory Factor Analysis and tested using Covariance-Based Structural Equation *** were then collected from a survey of 507 customers of two banks and two big telecommunication firms in *** results indicate that anthropomorphism and interaction do not play critical roles in generating customer trust in AI unless they create communication quality with *** ability of empathy response makes customers trust in various service *** application seems to be a good solution for service firms to enhance their relationship with customers in difficult circumstances,including a pandemic *** study delivers implications for enhancing AI adoption in the service firms that intend to innovate their future operations.

关键词： AI anthropomorphism empathy response future orientation interaction

Engine performance and combustion characteristics of a direct injection compression ignition engine fueled waste cooking oil synthetic diesel

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International Journal of Coal Science & Technology 2020年第3期7卷 560-570页

作者： Thanh Viet nguyen khanh Duc nguyen Nang Xuan Ho Vinh Duy nguyen Department of Internal Combustion Engine School of Transportation EngineeringHanoi University of Science and TechnologyHanoiViet Nam Faculty of Vehicle and Energy Engineering Phenikaa UniversityYen NghiaHa-Dong DistrictHanoiViet Nam

Biodiesels produced from various feedstocks have been considered as alternative fuels used in internal combustion engines without major *** research focuses on producing biodiesel from waste cooking oil(WCOSD)by the catalytic cracking method using MgO as the catalyst and comparing the engine operating characteristics of the test engine when using WCOSD and traditional diesel(CD)as test *** a result,the brake power of the test engine fueled WCOSD,and traditional diesel is ***,the engine fuel consumption in the case of using WCOSD is slight increases in some operating ***,the nitrogen oxides emissions of the test engine fueled WCOSD are higher than those of CD at all tested *** trend is opposite for hydrocarbon emission as the HC emission of the engine fueled by WCOSD reduces 26.3%on *** smoke emission of the test engine in case of using WCOSD is lower 17%on average than that of ***,the carbon monoxide emissions are lower at the low and medium loads and higher at the full *** results show that the new biodiesel has the same characteristics as those of commercial biodiesel and can be used as fuel for diesel engines.

关键词： Feedstock Waste cooking oil Engine characteristics Exhaust missions Ignition timing Fuel consumption

Theoretical basis of a beneficial role for vitamin D in viral hepatitis

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World Journal of Gastroenterology 2012年第38期18卷 5338-5350页

作者： khanh vinh quoc Luong Lan Thi Hoàng nguyen Vietnamese American Medical Research Foundation WestminsterCA 92683United States

Abnormal bone metabolism and dysfunction of the calcium-parathyroid hormone-vitamin D axis have been reported in patients with viral hepatitis. Some studies suggested a relationship between vitamin D and viral hepatitis. Genetic studies have provided an opportunity to identify the proteins that link vitamin D to the pathology of viral hepatitis (i.e., the major histocompatibility complex class Ⅱ molecules, the vitamin D receptor, cytochrome P 450 , the renin-angiotensin system, apolipoprotein E, liver X receptor, toll-like receptor, and the proteins regulated by the Sp1 promoter gene). Vitamin D also exerts its effects on viral hepatitis via non-genomic factors, i.e., matrix metalloproteinase, endothelial vascular growth factor, prostaglandins, cyclooxygenase-2, and oxidative stress. In conclusion, vitamin D could have a beneficial role in viral hepatitis. Calcitriol is best used for viral hepatitis because it is the active form of the vitamin D 3 metabolite.

关键词： Calcitriol Hepatitis Hepatitis B virus Hepatitis C virus Vitamin D

Electronic Band Structure of Carbon Nanotubes with Kekule Structure

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Chinese Physics Letters 2013年第9期30卷 97-100页

作者： nguyen Ngoc Hieu Le cong Nhan Center of Research and Development Duy Tan UniversityK7/25 Quang TrungDa NangViet Nam Department of Environmental Science Saigon University273 An Duong VuongHo Chi Minh cityViet Nam

Electronic band structure of carbon nanotubes with the Kekule structure is studied by the tight-binding *** give a complete geometrical approach to structural properties of carbon nanotubes with bond alternation,including chiral and achiral *** the Kekule is introduced,all carbon nanotubes become semiconducting with a small band gap at the Fermi *** band gap of the carbon nanotubes depends only on the difference between C–C bond lengths or the resonance integrals.

关键词： carbon structure Fermi

Heat Transfer and Fluid Flow of Nanofluids in Laminar Radial Flow Cooling Systems

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Journal of Thermal Science 2005年第4期14卷 362-367页

作者： Gilles ROY Samy Joseph PALM cong Tam nguyen Faculty of Engineering Universite de MonctonMonctonNBCanadaElA 3E9

Nanofluids are considered as interesting alternatives to conventional coolants. It is well known that traditional fluids have limited heat transfer capabilities when compared to common metals. It is therefore quite conceivable that a small amount of extremely fine metallic particles placed in suspension in traditional fluids will considerably increase their heat transfer performances. A numerical investigation into the heat transfer enhancement capabilities of coolants with suspended metallic nanoparticles inside a radial, laminar flow cooling configuration is presented. Temperature dependant nanofluid properties are evaluated from experimental data available in recent literature. Results indicate that considerable heat transfer increases are possible with the use of relatively small volume fractions of nanoparticles. Generally, however, these are accompanied by considerable increases in wall shear-stress. Results also show that predictions obtained with temperature variable nanofluid properties yield greater heat transfer capabilities and lower wall shear stresses when compared to predictions using constant properties.

关键词： nanofluids nanoparticles heat transfer laminar flow confined radial flow.

Thermal Performance Prediction in the Air Gap of a Rotor-Stator Configuration: Effects of Numerical Models

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Journal of Thermal Science 2020年第1期29卷 206-218页

作者： DANG Dinh-Dong PHAM Xuan-Tan nguyen Chi-cong Department of Mechanical Engineering École de technologie supérieureMontrealQCCanada Hydro-Québec’s research institute VarennesQCCanada

This study is dedicated to a numerical investigation of convective heat transfer on the rotor surfaces of a rotor-stator configuration that is typically found in large *** computational fluid dynamics calculations with two turbulence modelling approaches are used to predict the flow structure and heat transfer in the air gap of the rotor-stator *** steady state mixing plane approach is employed at the interface to couple the rotor and stator *** show that the location of mixing plane interface in the air gap plays an important role in the prediction of heat transfer on the pole ***,it is indicated that the prediction of temperature distribution on the pole face is greatly affected by the turbulence models ***,through a comparison between the pure convective and conjugate heat transfer methodologies,it is shown that the inclusion of solid domain into the numerical model significantly improves the thermal prediction of the solid components of the machine.

关键词： hydro-generators electrical cooling mixing plane windage loss conjugate heat transfer

Uncertainty analysis of hydrological modeling in a tropicalarea using different algorithms

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Frontiers of Earth Science 2018年第4期12卷 661-671页

作者： Ammar RAFIEI EMAM Martin KAPPAS Steven FASSNACHT nguyen Hoang khanh LINH Department of Cartography GIS and Remote SensingUniversity of Goettingen37077GoettingenGermany Colorado State University Fort CollinsCO 80523-1476USA Faculty of Land Resources and Agricultural Environment (FLRAE) Flue University of Agriculture and Forestry (F1UAF)Hue UniversityHue City 0084Vietnam

Hydrological modeling outputs are subject to uncertainty resulting from different sources of errors (e.g., error in input data, model structure, and model parameters), making quantification of uncertainty in hydrological modeling imperative and meant to improve reliability of modeling results. The uncertainty analysis must solve difficulties in calibration of hydrological models, which further increase in areas with data scarcity. The purpose of this study is to apply four uncertainty analysis algorithms to a semi-distributed hydrological model, quantifying different source of uncertainties (especially parameter uncertainty) and evaluate their performance. In this study, the Soil and Water Assessment Tools (SWAT) eco-hydrological model was implemented for the watershed in the center of Vietnam. The sensitivity of parameters was analyzed, and the model was calibrated. The uncertainty analysis for the hydrological model was conducted based on four algorithms: Generalized Likelihood Uncertainty Estimation (GLUE), Sequential Uncertainty Fitting (SUFI), Parameter Solution method (ParaSol) and Particle Swarm Optimization (PSO). The performance of the algorithms was compared using P-factor and Rfactor, coefficient of determination (R2), the Nash Sutcliffe coefficient of efficiency (NSE) and Percent Bias (PBIAS). The results showed the high performance of SUFI and PSO with P-factor>0.83, R-factor 0.91, NSE>0.89, and 0.18<0.32. Hence, we would suggest to use SUFI-2 initially to set the parameter ranges, and further use PSO for final analysis. Indeed, the uncertainty analysis must be accounted when the outcomes of the model use for policy or management decisions.

关键词： SWAT-CUP GLUE SUFI2 ParaSol PSO Vietnam