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ON BOUNDEDNESS PROPERTY OF SINGULAR INTEGRAL OPERATORS ASSOCIATED TO A SCHRODINGER OPERATOR IN A GENERALIZED MORREY SPACE AND APPLICATIONS

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Acta Mathematica Scientia 2020年第5期40卷 1171-1184页

作者： xuan Truong LE thanh Nhan nguyen Ngoc Trong nguyen Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Due Thang UniversityHo Chi Minh CityVietnam Faculty of Mathematics and Statistics Ton Due Thang UniversityHo Chi Minh CityVietnam Department of Mathematics Ho Chi Minh City University of EducationHo Chi Minh CityVietnam Department of Primary Education Ho Chi Minh City University of EducationHo Chi Minh CityVietnam

In this paper,we provide the boundedness property of the Riesz transforms associated to the Schrodinger operator■=-Δ+V in a new weighted Morrey space which is the generalized version of many previous Morrey type *** additional potential V considered in this paper is a non-negative function satisfying the suitable reverse Holder's *** results are new and general in many cases of *** an application of the boundedness property of these singular integral operators,we obtain some regularity results of solutions to Schrodinger equations in the new Morrey space.

关键词： weighted Morrey spaces Schodinger operator riesz transforms Regularity estima tes

Assessment of Livelihood Vulnerability to Drought: A Case Study in Dak Nong Province, Vietnam

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International Journal of Disaster Risk Science 2019年第4期10卷 604-615页

作者： nguyen Thi thanh Thao Dao nguyen Khoi Tran thanh xuan Bernard Tychon Universite de Liege 6700 ArlonBelgium Institute for Environmental Science Engineeringand ManagementIndustrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Institute of Research and Development Duy Tan UniversityDa NangVietnam Faculty of Environment University of ScienceVietnam National University Ho Chi Minh CityHo Chi Minh CityVietnam NTT Institute of Hi-Technology Nguyen Tat Thanh UniversityHo Chi Minh CityVietnam

In recent years,droughts have strongly affected the Central Highlands of Vietnam and have resulted in crop damage,yield decline,and serious water *** study investigated the livelihood vulnerability of five communities of farmers who are exposed to droughts in one of the more vulnerable regions of Vietnam—Dak Nong Province.A survey of 250 households was conducted in the five communities to collect data on the region’s sociodemographic profile,livelihood systems,social networks,health status,food and water security,drought conditions,and climate *** were aggregated using a livelihood vulnerability index and the IPCC vulnerability *** survey results indicate that Quang Phu community is the most vulnerable of the study’s communities,followed by Nam N’dir,Dak Nang,Duc Xuyen,and Dak D’ro in descending order of *** availability and livelihood strategies are the most important variables in determining the vulnerability of the five surveyed *** order to reduce vulnerability to droughts,water management practices and livelihood diversification in farming and nonfarming activities are recommended for the study area.

关键词： Agricultural drought Livelihood vulnerability Vietnam Vulnerability indicators

Multiparticle^(nat)Sr(γ,xny p)reactions induced with bremsstrahlung end-point energies of 55,60,and 65 MeV

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Chinese Physics C 2022年第9期46卷 185-196页

作者： nguyen Van Do nguyen thanh Luan nguyen Thi xuan Kim Tien thanh nguyen Thi Hien Guinyun Kim Institute of Theoretical and Applied Research Duy Tan UniversityHanoi 100000Vietnam Faculty of Natural Sciences Duy Tan UniversityDa Nang 550000Vietnam Institute of Physics Vietnam Academy of Science and Technology10 Dao TanHanoi 10000Vietnam Department of Physics Kyungpook National UniversityDaegu 415661Republic of Korea Graduate School of Science and Technology Vietnam Academy of Science and Technology18 Hoang Quoc VietHanoiVietnam

This study measured the yields of the radionuclides^(82)Sr,^(83(m+g))Sr,^(85m)Sr,^(85g)Sr,^(87m)Sr,^(81(g+0.976m))Rb,^(82m)Rb,^(83g)Rb,^(84(m+g))Rb,and^(86(m+g))Rb produced in^(nat)Sr(γ,xnyp)multiparticle reactions with bremsstrahlung end-point energies of 55,60,and 65 *** bremsstrahlung radiation was generated using the 100-MeV electron linear accelerator at the Pohang Accelerator Laboratory,Korea,and the reaction yields were derived from the induced activitiesmeasured using off-lineγ-ray *** obtain accurate experimental results,we performed the necessaryγ-ray interference *** experimental results were compared with the theoretical predictions obtained using the TALYS-1.95 statistical nuclear model *** calculations were performed using six different level-density models to ascertain which model best fitted the experimental *** dependence of the reaction yield on the incident bremsstrahlung energy and on the number of nucleons emitted by the photonuclear reactions was also investigated.

关键词： reaction yield activation method ^(nat)Sr(γ xnyp)reactions γ-ray spectrometry 55- 60- and 65-MeV bremsstrahlung.

Spatiotemporal Trend Analysis of Precipitation Extremes in Ho Chi Minh City, Vietnam During 1980–2017

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International Journal of Disaster Risk Science 2021年第1期12卷 131-146页

作者： nguyen Trong Quan Dao nguyen Khoi nguyen xuan Hoan nguyen Ky Phung thanh Duc Dang Faculty of Environmental and Food Engineering Nguyen Tat Thanh UniversityHo Chi Minh City 700000Vietnam Faculty of Environment University of ScienceHo Chi Minh City 700000Vietnam Vietnam National University Ho Chi Minh City 700000Vietnam Ho Chi Minh City University of Food Industry Ho Chi Minh City 700000Vietnam Institute for Computational Science and Technology Ho Chi Minh City 700000Vietnam Engineering Systems and Design Pillar Singapore University of Technology and DesignTampines 487372Singapore

In this study,the spatiotemporal variability of trends in extreme precipitation events in Ho Chi Minh City during the period 1980–2017 was analyzed based on several core extreme precipitation indices(Rx1 day,Rx5 day,CDD,CWD,R20 mm,R25 mm,R95 p,and SDII).The nonparametric Mann–Kendall and Sen’s slope methods were used to compute the statistical strength,stability,and magnitude of trends in annual rainfall,as well as the extreme precipitation *** found that 64%of the stations had statistically significant upward trends in yearly rainfall,with high magnitudes frequently observed in the northern and southern regions of the *** the extreme precipitation indices,only SDII and R25 mm showed dominantly significant ***,there were increasing trends in the frequency and duration at the southern and central regions of the city during the study ***,El Ni?o-Southern Oscillation and Pacific Decadal Oscillation positively correlated with the duration and negatively correlated with the intensity and frequency of extreme ***,water management plans should be adjusted appropriately to reduce the severe impacts of precipitation extremes on communities and ecosystems.

关键词： Spatiotemporal trend Extreme precipitation Extreme precipitation indices Ho Chi Minh City

Designing Software to Analyze Sewing Process of Industrial Knitted Products

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Computer Systems Science & Engineering 2023年第2期44卷 1837-1852页

作者： Phan thanh Thao nguyen thanh Hung Pham Thi Le My nguyen xuan Hiep Duy-Nam Phan Hanoi University of Science and Technology Hanoi10000Vietnam

In the textile industry,garment manufacturing contains four major pro-cesses containing cutting,sewing,ﬁnishing,and *** is the most crucial and intricate section,dealing with a large number of varied operations.A successful sewing process needs to be optimized regarding different factors,including time,sewing equipment,and skilled *** lineﬂow is combined by a set of operations with a particular *** utmost impor-tance of all garment industry is to arrange the workstations to minimize the num-ber of employees in order to produce at the best productive rate with the most reasonable cost,shortest time,and satisfying *** most garment factories,the production lines are balanced using the empirical judgment of the line *** the whole process the data of production time at each step,labor pro-ductivity,proper choices of equipment were always needed to calculate line efﬁ*** far as the issue is concerned,there has not been an academically sewing process analyzing software providing adequate data of sewing motions and sewing time as the credible input for the line balancing *** this goal,this paper presents the results of research on optimizing academically self-built software to analyze the sewing process of knitted products applied to industrial production using Java programming language on Google *** results achieved by the software are not only to analyze sewing products and the technological sewing process,calculate the sewing time on the machine but also analyze the sewing activities of workers into manipulations,movements,and motions to calculate the preparation time for two typical knitted products,namely,Polo-Shirt and T-Shirt with the case studies at General Textile Garment Joint Stock Company Hanoi and Star Fashion Company Limited.

关键词： Sewing motion sewing time GSD MTM polo-shirt T-shirt sewing process sewing operation analyzing software

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

A Chemical Reactor Network for Oxides of Nitrogen Emission Prediction in Gas Turbine Combustor

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Journal of Thermal Science 2014年第3期23卷 279-284页

作者： nguyen thanh Hao Industrial University of HoChiMinh City

This study presents the use of a new chemical reactor network(CRN) model and non-uniform injectors to predict the NOx emission pollutant in gas turbine combustor. The CRN uses information from Computational Fluid Dynamics(CFD) combustion analysis with two injectors of CH4-air mixture. The injectors of CH4-air mixture have different lean equivalence ratio, and they control fuel flow to stabilize combustion and adjust combustor's equivalence ratio. Non-uniform injector is applied to improve the burning process of the turbine combustor. The results of the new CRN for NOx prediction in the gas turbine combustor show very good agreement with the experimental data from Korea Electric Power Research Institute.

关键词： Chemical Reactor Networks (CRN) Computational Fluid Dynamics (CFD) Perfectly Stirred Reactor (PSR) Plug Flow Reactor (PFR) Gas Turbine Combustor Oxides of Nitrogen Emission (NOx).

Data-driven approach to solve vertical drain under time-dependent loading

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Frontiers of Structural and Civil Engineering 2021年第3期15卷 696-711页

作者： Trong NGHIA-nguyen Mamoru KIKUMOTO Samir KHATIR Salisa CHAIYAPUT Hnguyen-xuan thanh CUONG-LE Department of Civil Engineering Yokohama National UniversityYokohama 240-8501Japan Faculty of Civil Engineering Ho Chi Minh City Open UniversityHo Chi Minh City 70000Vietnam Department of Electrical Energy MetalsMechanical Constructions and SystemsFaculty of Engineering and ArchitectureGhent UniversityGhent 9000Belgium Department of Civil Engineering School of EngineeringKing Mongkut’s Institute of Technology LadkrabangBangkok 10520Thailand CIRTECH Institute Ho Chi Minh City University of Technology(HUTECH)Ho Chi Minh City 708300Vietnam

Currently,the vertical drain consolidation problem is solved by numerous analytical solutions,such as time-dependent solutions and linear or parabolic radial drainage in the smear zone,and no artificial intelligence(AI)approach has been ***,in this study,a new hybrid model based on deep neural networks(DNNs),particle swarm optimization(PSO),and genetic algorithms(GAs)is proposed to solve this *** DNN can effectively simulate any sophisticated equation,and the PSO and GA can optimize the selected DNN and improve the performance of the prediction *** the present study,analytical solutions to vertical drains in the literature are incorporated into the DNN–PSO and DNN–GA prediction models with three different radial drainage patterns in the smear zone under timedependent *** verification performed with analytical solutions and measurements from three full-scale embankment tests revealed promising applications of the proposed approach.

关键词： vertical drain artificial neural network time-dependent loading deep learning network genetic algorithm particle swarm optimization

A Correlation Coefficient Approach for Evaluation of Stiffness Degradation of Beams Under Moving Load

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Computers, Materials & Continua 2019年第7期61卷 27-53页

作者： thanh Q.nguyen Thao T.D.nguyen H.nguyen-xuan Nhi K.Ngo Laboratory of Applied Mechanics(LAM) Ho Chi Minh City University of TechnologyHo Chi Minh City740030Vietnam Saigon Hi-Tech Park Training Center Ho Chi Minh City715650Vietnam Ho Chi Minh City Department of Transportation and Communication Ho Chi Minh City710100Vietnam CIRTECH Institute Ho Chi Minh City University of Technology(HUTECH)Ho Chi Minh City717349Vietnam Department of Physical Therapy Graduate Institute of Rehabilitation ScienceChina Medical UniversityTaichung40402Taiwan

This paper presents a new approach using correlation and cross-correlation coefficients to evaluate the stiffness degradation of beams under moving *** theoretical study of identifying defects by vibration methods showed that the traditional methods derived from the vibration measurement data have not met the needs of the actual *** show that the correlation coefficients allow us to evaluate the degree and the effectiveness of the defects on *** the same time,the cross-correlation model is the basis for determining the relative position of *** results of this study are experimentally conducted to confirm the relationship between the correlation coefficients and the existence of the *** particular,the manuscript shows that the sensitivity of the correlation coefficients and cross-correlation is much higher than the parameters such as changes in stiffness(EJ)and natural frequency values(Δf).This study suggests using the above parameters to evaluate the stiffness degradation of beams by vibration measurement data in practice.

关键词： Correlation coefficient cross-correlation vibration signal vibration amplitude frequency