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Acta Mathematica Scientia 2021年第4期41卷 1151-1168页

作者： Yongjian LIU Stanisiaw MIGÓRSKI Van Thien nguyen Shengda ZHENG Guangxi Colleges and Universities Key Laboratory of Complex System Optimization and Big Data Processing Yulin Normal UniversityYulin 537000China College of Applied Mathematics Chengdu University of Information TechnologyChengdu 610225China Jagiellonian University in Krakow Chair of Optimization and Controlul.Lojasiewicza 630348 KrakowPoland Departement of Mathematics FPT UniversityEducation ZoneHoa Lac High Tech ParkKm29 Thang Long HighwayThach That WardHanoiVietnam

The goal of this paper is to study a mathematical model of a nonlinear static frictional contact problem in elasticity with the mixed boundary conditions described by a combination of the Signorini unilateral frictionless contact condition,and nonmonotone multivalued contact,and friction laws of subdifferential ***,under suitable assumptions,we deliver the weak formulation of the contact model,which is an elliptic system with Lagrange multipliers,and which consists of a hemivariational inequality and a variational ***,we prove the solvability of the contact ***,employing the notion of H-convergence of nonlinear elasticity tensors,we provide a result on the convergence of solutions under perturbations which appear in the elasticity operator,body forces,and surface tractions.

关键词： Mixed variational-hemi variational inequality H-convergence homogenization Clarke subgradient Lagrange multiplier elasticity operator

Assessment of Radiation Dose Caused by Radioactive Gaseous Effluent Released from Nuclear Power Plant Ninh Thuan 1 under Scenario of Normal Working Conditions

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World Journal of Nuclear Science and Technology 2015年第3期5卷 183-191页

作者： nguyen Tuan Khai Do Xuan Anh Le Dinh Cuong Duong Duc Thang Vuong Thu Bac nguyen Thi Thu Ha nguyen Quang long Trinh Van Giap nguyen Hao Quang Institute for Nuclear Science and Technology (INST) Hanoi Vietnam Vietnam Atomic Energy Institute (VINATOM) Hanoi Vietnam

Based on guides RG 1.109, RG 1.111 published by United States Nuclear Regulatory Commission (USNRC), our research concentrates in assessing radiation doses caused by radioactive substances released from the nuclear power plant (NPP) Ninh Thuan 1 under the scenario of normal operation using software package NRCDose72 provided by the USNRC. The database including the released radioactive nuclides, meteorology, terrain, population and agricultural production activities have been collected and processed to build the input data for the model calculation. The wind rose distribution obtained from the meteorological data in a five-year period from 2009-2013 showed that the radioactive nuclides released to environment spread in two main wind directions which are North East and South West. The X/Q (s/m3) and D/Q (s/m2) qualities which are, respectively, the ratio of activity concentration to release rate and that of deposition density of radioactive nuclides to release rate were calculated within an area of 80 km radius from the NPP site using XOQDOQ. Population doses were calculated using GASPAR. The XOQDOQ and GASPAR are two specific softwares in NRCDose72 package.

关键词： NPP Radioactive Release Radiation Dose Population Dose X/Q and D/Q

Some problems on the research and development of the application of methane draining boring technology to prevent hazards in underground coal mines in Vietnam

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Journal of Coal Science & Engineering(China) 2009年第2期15卷 129-133页

作者： nguyen Xuan-Thao nguyen Tran-Tuan TRAN Dinh-Kien Institute of Mining Science and Technology University of Mining and Geology

Underground coal mining activities in the Quangninh coal basin (in the North ofVietnam) have been carried out at a depth of-130 m to-150 m,and in the near future thismining depth will become-300 m and-500 *** with the increasing coal output,the quantity of methane and other mine gases emitted from coal beds during mining activitieswill grow bigger and *** to the forecast of the coal mining industry,ifmines go deeper downward,all underground coal mines in the Quangninh basin will beclassified into the mine group with the dangerous level of methane *** gascontrol and management operations with conventional ventilation are less effective andentail high *** of the main solutions is to carry out short,medium and longboreholes for controlling and recovering methane and other mine gases from coal bedsbefore mining *** of drilling activities for methane gas recovery from coalseams with horizontal bore holes at underground coal mines depends on many factors includingthe mine gas draining borehole layout at the roadways,gas content in the coalbeds,technologies for mine gas draining boring activities,and so *** gas existsin the coal beds under the adhesive state with stable physical and chemical *** orderto recover these gases,it is necessary to carry out boreholes and create artificial joints(collecting pits) in coal beds with the impulse method (hydraulic separation method).

关键词： problems methane draining bodng technology Vietnam

Effective plant discrimination based on the combination of local binary pattern operators and multiclass support vector machine methods

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Information Processing in Agriculture 2019年第1期6卷 116-131页

作者： Vi nguyen Thanh Le Beniamin Apopei Kamal Alameh Edith Cowan University–Electron Science Research Institute Australia

Accurate crop and weed discrimination plays a critical role in addressing the challenges of weed management in *** use of herbicides is currently the most common approach to weed ***,herbicide resistant plants have long been recognised as a major concern due to the excessive use of *** weed detection techniques can reduce the cost of weed management and improve crop quality and yield.A computationally efficient and robust plant classification algorithm is developed and applied to the classification of three crops:Brassica napus(canola),Zea mays(maize/corn),and *** developed algorithm is based on the combination of Local Binary Pattern(LBP)operators,for the extraction of crop leaf textural features and Support vector machine(SVM)method,for multiclass plant *** paper presents the first investigation of the accuracy of the combined LBP algorithms,trained using a large dataset of canola,radish and barley leaf images captured by a testing facility under simulated field *** dataset has four subclasses,background,canola,corn,and radish,with 24,000 images used for training and 6000 images,for *** dataset is referred herein as "bccr-segset"and published *** each subclass,plant images are collected at four crop growth ***,the algorithm demonstrates plant classification accuracy as high as 91.85%,for the four classes.

关键词： Plant discrimination Classification LBP PCA and SVM

The Continuous Knapsack Problem with Capacities

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Journal of the Operations Research Society of China 2021年第3期9卷 713-721页

作者： Huynh Duc Quoc nguyen Chi Tam Tran Hoai Ngoc Nhan Department of Mathematics College of Natural ScienceCan Tho UniversityCan Tho City 900900Vietnam Faculty of Basic Sciences Vinh Long University of Technology EducationVinh Long 940000Vietnam

We address a variant of the continuous knapsack problem,where capacities regarding costs of items are given into *** prove that the problem is NP-complete although the classical continuous knapsack problem is solvable in linear *** the case that there exists exactly one capacity for all items,we solve the corresponding problem in O(n log n)time,where n is the number of items.

关键词： Knapsack problem Complexity Capacity Polynomially solvabl

Spatio-Temporal Determination of Irrigated Paddy Rice Pixels Using Evapotranspiration and Vegetation Indices: A Case Study for Ca River Basin in Vietnam

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Journal of Geoscience and Environment Protection 2020年第12期8卷 94-107页

作者： Chung N. Luong Lan T. Ha Thanh C. Pham Hung X. Dinh Thanh T. hoang Hoan N. nguyen Tuan V. nguyen Phung X. nguyen Institute of Water Resources Planning Hoan Kiem Hanoi Vietnam Division of Water Resources Planning in Northern Central Region Institute of Water Resources Planning Hoan Kiem Hanoi Vietnam Department of Training and International Cooperation Institute of Water Resources Planning Hoan Kiem Hanoi Vietnam Division of Hydro-Meteorology Institute of Water Resources Planning Hoan Kiem Hanoi Vietnam

Improving irrigation monitoring and efficiency is a current priority of the Government of Vietnam, focusing primarily on the agricultural sector which consumes most of the available surface and groundwater. This paper presents how remote sensing can be used in an integrated manner to achieve better understanding of key eco-hydrological processes including precipitation, evapotran-spiration, irrigation and crop growth. The results indicated that Normalized Difference Vegetation Index derived from Moderate Resolution Imaging Spectroradiometer (MODIS) can be applied to determine irrigated pixels on a spatial and temporal basis. The validation using measured water level showed a Pearson correlation of 0.7 proving the high accuracy of this method. The inclusion of these technologies is deemed necessary to improve water resources monitoring and management and hence, ensure long-term drought resilience and water and food security. Ca River Basin in the central Vietnam was selected as a case study to test this approach.

关键词： Remote Sensing Drought Management Irrigated Paddy

Biventricular pulsus alternans: An echocardiographic finding in patient with pulmonary embolism

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World Journal of Clinical Cases 2013年第5期1卷 162-165页

作者： Tin nguyen long-Bao Cao Minh Tran Assad Movahed Department of Cardiovascular Sciences East Carolina UniversityBrody School of Medicine East Carolina Heart Institute Greenville NC 27834 United States

Pulsus alternans is characterized by regular rhythm with beat-to-beat alternation of systolic pressures. Left ventricular alternans is usually found in severe left ventricular dysfunction due to cardiomyopathy, coronary artery disease, systemic hypertension, and aortic stenosis. Right ventricular alternans is usually associated with left ventricular alternans, right ventricular dysfunction, pulmonary embolism, and pulmonary hypertension. Biventricular alternans is rare and associated with severe left ventricular dysfunction and left anterior descending coronary artery disease. The exact mechanism of pulsus alternans has not been clearly delineated, and it has been remained a subject of investigation and conjecture since the nineteenth century. Two fundamental mechanisms have been proposed to explain ventricular alteration. The first, based on the Frank-Starling mechanism, proposes beat-to-beat alteration in end-diastolic volume accounted for the alternating contractile force. The second proposed mechanism which explains the physiology of pulsus alternans involves the abnormal calcium handling by cardiac myocytes. To the best of our knowledge, biventricular alternans in pulmonaryembolism has not been previously reported in the medical literature. We present and discuss the mechanisms of pulsus alternans and its clinical implications.

关键词： Pulsus alternans Biventricular alternans Pulmonary embolism

Profit Optimization of External Cylindrical Grinding

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Journal of Environmental Science and Engineering(B) 2014年第5期3卷 227-231页

作者： Vu Ngoc Pi Banh Tien long Vu Hong Khiem nguyen Hong Quan Faculty of Mechanical Engineering Thai Nguyen University of Technology Thai Nguyen 23000 Vietnam School of Mechanical Engineering Hanoi University of Technology Hanoi 10000 Vietnam

This article presents a study on profit optimization of external cylindrical grinding. In the optimization problem, the influences of several grinding process parameters such as the initial grinding wheel diameter, the wheel life, the total dressing depth as well as the effect of many cost components were investigated. A model for determination of optimum exchanged grinding wheel diameter was proposed. With this optimum diameter, a new and effective way of using the grinding wheel was proposed.

关键词： Grinding process external cylindrical grinding profit optimization.

Remote Sensing-Based Accounting of Reservoir’s Water Storage for Water Scarcity Mitigation: A Case Study for Small and Medium Irrigation Dams in Vietnam

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Journal of Geoscience and Environment Protection 2021年第11期9卷 89-97页

作者： Hung X. Dinh Thanh T. hoang Lan T. Ha Tuan V. nguyen Thanh C. Pham Minh C. nguyen Hiep T. Luong Institute of Water Resources Planning Hanoi Vietnam

Integrated water resources management requires consistent and accurate data on available water storage in reservoirs as well as water stress level. Vietnam is enduring a significant deficit in collecting necessary information to manage its water resources in that manner. While reservoirs are abundant, the majority of them were constructed a long ago and often lack of regular and adequate measurement on storage volume. Furthermore, the condition of water stress is often missing or remains bias leading to certain risks in reservoir operation, e.g. during water scarcity period. This paper presents how remote sensing data can be used to acquire needed information that is fundamental to understand water resources conditions. The results indicated that Sentinel-1 and Moderate Resolution Imaging Spectroradiometer (MODIS) can be applied to determine water surface area and water stress, through vegetation health index (VHI). This information is deemed necessary to improve water resources monitoring and management and hence, ensure long-term drought resilience and water and food security.

关键词： Remote Sensing Water Scarcity Management Reservoir Volume

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不锈钢基板表面粗糙度对水膜吸附夹持的影响

表面技术 2019年第9期48卷 97-103页

作者：黄晟杭伟陈芝向袁巨龙赵萍 Duc-Nam nguyen 浙江工业大学特种装备制造与先进加工技术教育部重点实验室杭州310014 胡志明市工业大学越南胡志明市800010

目的从水膜吸附的功能研究出发,对不锈钢基板表面进行不同粗糙度处理,并测量不同基板对蓝宝石晶片的吸附力以及切向摩擦力的影响,从而得出粗糙度对水膜吸附效果的影响规律。方法通过砂纸打磨、研磨、抛光等方法,得到不同平均粗糙度(Sa=6... 详细信息

目的从水膜吸附的功能研究出发,对不锈钢基板表面进行不同粗糙度处理,并测量不同基板对蓝宝石晶片的吸附力以及切向摩擦力的影响,从而得出粗糙度对水膜吸附效果的影响规律。方法通过砂纸打磨、研磨、抛光等方法,得到不同平均粗糙度(Sa=633.4、332.6、116.2、64.5、41.4nm)的不锈钢基板。利用接触角计对液滴在基板表面形成的静态接触角进行拍摄,得出不同粗糙度不锈钢表面的润湿性能。开发设计高精度的多维力测量平台,测量蓝宝石晶片在不同粗糙度不锈钢基板上润湿后的吸附力和切向摩擦力,并与未润湿的基板得到的测量结果进行对比研究,得出粗糙度对吸附力和摩擦系数的影响规律。结果5种粗糙度的不锈钢基板的静态接触角均小于90°,属于亲水性材料。水膜吸附条件下,吸附力大小随粗糙度的增加而减小;接触角大小随粗糙度的增加而增大,且吸附力的减小率和接触角的增大率趋势相似;摩擦系数随粗糙度的增大而增大。基板表面粗糙度较大时,水膜提供一定的粘滞力,使水膜吸附条件下比无水膜时的切向摩擦力更大;当粗糙度较小时,水膜更多的是润滑作用,此时比无水膜时的切向摩擦力要小得多。结论基板表面粗糙度较小时,基板能提供较大的吸附力,而摩擦力不如无水膜时的大;基板粗糙度较大时,吸附力相对较弱,但是摩擦力比无水膜的更大。在选择不锈钢基板作为水膜吸附夹持基板时,在保证足够吸附力的条件下,可以适当提高基板的表面粗糙度,抵抗晶片抛光过程中受到抛光垫的摩擦力。

关键词：不锈钢水膜吸附亲疏水性粗糙度摩擦系数