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Behavior of noncircular tunnels excavated in stratified rock masses-Case of underground coal mines

Journal of Rock Mechanics and Geotechnical Engineering 2019年第1期11卷 99-110页

作者： Ngoc Anh Do Daniel Dias van Diep Dinh Tien Tung tran van Canh Dao Viet Doan Dao Phuc Nhan Nguyen Department of Underground and Mining Construction.Faculty of Civil Engineering Hanoi University of Mining and Ceology School of Automotive and transportation Engineering Hefei University of Technology Laboratory 35R Crenoble Alpes University

The amount of tunnels excavated along stratified/sedimentary rock masses in Quangninh coal mine area,Vietnam, is gradually increasing. Rock mass in Quangninh is characterized by beddings between rock layers. The behavior of stratified rock masses surrounding the tunnels depends on both the intact rock and the beddings between rock layers. The main characteristics of stratified rock masses that need to be considered are their heterogeneity and anisotropy. Depending on the dip angle of rock layers, movements and failure zones developed surrounding the tunnels can be asymmetrical over the vertical axis of tunnel. This asymmetry causes adverse behaviors of the tunnel structures. The objective of this study is to highlight convergences and yielded zones developed in rock masses surrounding noncircular tunnels in Quangninh coal mine area using a finite element method. The presence of bedding joints is explicitly simulated. The numerical results indicated that with the increase in dip angle of bedding joints, the stress asymmetry over the tunnel vertical axis increases. It gradually leads to an asymmetry of the failure zone surrounding the tunnel. An increase of rock mass quality means a decrease of rock mass sensitivity to the discontinuities. In addition,a dip angle of the bedding joints of approximately 45° could be considered as the critical angle at which the rock mass mechanism changes between sliding and bending.

关键词： Tunnel Bedding Stratification Anisotropic Heterogeneity

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Flow Visualization of Rhinoceros Beetle （Trypoxylus dichotomus） in Free Flight

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Journal of Bionic Engineering 2012年第3期9卷 304-314页

作者： Tien van Truong Tuyen Quang Le Hieu Trung tran Hoon Cheol Parka Kwang Joon Yoon Doyoung Byun . Department of Aerospace Information Engineering Konkuk University Seoul 143-70 l Republic of Korea 2.Costal Engineering and Ocean Energy Research Department Korea Ocean Research and Development Institute 454 Haeanro Sangrok-gu Ansan 426-744 Republic of Korea Department of Advanced Technology Fusion Konkuk University Seoul 143-701 Republic of Korea Department of Mechanical Engineering Sungkyunkwan University Suwon 440-746 Republic of Korea

Aerodynamic characteristics of the beetle, Trypoxylus dichotomus, which has a pair of elytra （forewings） and flexible hind wings, are investigated. Visualization experiments were conducted for various flight conditions of a beetle, Trypoxylus di- chotomus： free, tethered, hovering, forward and climbing flights. Leading edge, trailing edge and tip vortices on both wings were observed clearly. The leading edge vortex was stable and remained on the top surface of the elytron for a wide interval during the downstroke of free forward flight. Hence, the elytron may have a considerable role in lift force generation of the beetle. In addition, we reveal a suction phenomenon between the gaps of the hind wing and the elytron in upstroke that may improve the positive lift force on the hind wing. We also found the reverse clap-fling mechanism of the T. dichotomus beetle in hovering flight. The hind wings touch together at the beginning of the upstroke. The vortex generation, shedding and interaction give a better understanding of the detailed aerodynamic mechanism of beetle flight.

关键词： beetle smoke wire visualization free flight hovering flight wing interaction elytron effect

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Prediction of falling weight deflectometer parameters using hybrid model of genetic algorithm and adaptive neuro-fuzzy inference system

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Frontiers of Structural and Civil Engineering 2023年第5期17卷 812-826页

作者： Long Hoang NGUYEN Dung Quang VU Duc Dam NGUYEN Fazal E.JALAL Mudassir IQBAL vinh The DANG Hiep van LE Indra PRAKASH Binh Thai PHAM Faculty of Civil Engineering University of Transport TechnologyHanoi 10000Vietnam Department of Civil Engineering State Key Laboratory of Ocean EngineeringShanghai Jiao Tong UniversityShanghai 200025China Department of Civil Engineering University of Engineering and TechnologyPeshawar 25120Pakistan DDG(R)Geological Survey of India Gandhinagar 382010India

A falling weight deflectometer is a testing device used in civil engineering to measure and evaluate the physical properties of pavements,such as the modulus of the subgrade reaction(Y1)and the elastic modulus of the slab(Y2),which are crucial for assessing the structural strength of *** this study,we developed a novel hybrid artificial intelligence model,i.e.,a genetic algorithm(GA)-optimized adaptive neuro-fuzzy inference system(ANFIS-GA),to predict Y1 and Y2 based on easily determined 13 parameters of rigid *** performance of the novel ANFIS-GA model was compared to that of other benchmark models,namely logistic regression(LR)and radial basis function regression(RBFR)*** models were validated using standard statistical measures,namely,the coefficient of correlation(R),mean absolute error(MAE),and root mean square error(RMSE).The results indicated that the ANFIS-GA model was the best at predicting Y1(R=0.945)and Y2(R=0.887)compared to the LR and RBFR ***,the ANFIS-GA model can be used to accurately predict Y1 and Y2 based on easily measured parameters for the appropriate and rapid assessment of the quality and strength of pavements.

关键词： falling weight deflectometer modulus of subgrade reaction elastic modulus metaheuristic algorithms

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DENSITY ESTIMATES FOR SOLUTIONS OF STOCHASTIC FUNCTIONAL DIFFERENTIAL EQUATIONS

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Acta Mathematica Scientia 2019年第4期39卷 955-970页

作者： Nguyen Tien DUNG Ta Cong SON tran Manh CUONG Nguyen van TAN Trinh Nhu QUYNH Department of Mathematics FPT University Hoa Lac High Tech Park Hanoi Vietnam Department of Mathematics VNU Hanoi University of Science 334 Nguyen Trai Thanh Xuan Hanoi Vietnam Department of Foundation Academy of Cryptography Techniques Hl Chien Thang Thanh Tri Hanoi Vietnam Military Information Technology Institute 17 Hoang Sam Cau Giay Hanoi Vietnam

In this article, we investigate the density of the solution to a class of stochastic functional differential equations by means of Malliavin calculus. Our aim is to provide upper and lower Gaussian estimates for the d... 详细信息

关键词： Stochastic functional differential equations density estimates Malliavin calculus

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Assessment of Groundwater Recharge from Rainfall in the Plain of Cai Phan Rang, Vietnam

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Journal of Environmental Science and Engineering(A) 2014年第3期3卷 141-149页

作者： Chau tran vinh Nguyen Minh Khuyen Nguyen Hong Hieu Doan van Long Nguyen Tien Bach Trinh ThiThu van Department of Water Resources Management Ministry of Natural Resources and Environment Hanoi 100000 Vietnam

This paper presents the quantitative assessment results of rainwater supply to groundwater in Cai Phan Rang River basin, Ninh Thuan province, Vietnam. In order to obtain the results, the authors developed two experimental areas with 10 wells which were monitored in one year to assess the infiltration supply of rainwater to groundwater. The results of this research assessed the amount of rainwater infiltrates into groundwater varies from 307.16-314.98 tam·year^-1, average is 311 mm·year^-1. The findings are significant in terms of science which identify sources of groundwater storage from the infiltration supply of rainwater. The findings are also practical in suggesting measures to reserve groundwater for the purpose of socio-economic development in the study area.

关键词： Groundwater recharge rainwater infiltration rainwater infiltration into groundwater.

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Microwave absorption of magnesium/hydrogen-treated titanium dioxide nanoparticles

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Nano Materials Science 2019年第1期1卷 48-59页

作者： Michael Green Anh Thi van tran Russell Smedley Adam Roach James Murowchick Xiaobo Chen Department of Chemistry University of Missouri-Kansas City Kansas City MO 64110 USA Department of Geosciences University of Missouri-Kansas City Kansas City MO 64110 USA

Interactions between materials and electromagnetic irradiations in the microwave frequency are critical for many civil and military applications, such as radar detection, communications, information processing and transport et al. Dipole rotations or magnetic domain resonance are the mainly traditional mechanisms for microwave absorption. The recent finding of the excellent microwave absorption from hydrogenated TiO2 nanoparticles provides us an alternative approach for achieving such absorption, by manipulating the structural defects inside nanoparticles through hydrogenation. In this study, we demonstrate that the microwave absorption can be not only achieved but fine-tuned with TiO2 nanoparticles thermally treated in a Mg/H2 environment. Their position and efficiency can be effectively controlled by the treating temperature. Specifically, the microwave absorption position shifts to the lower frequency region as the treating temperature increases, and there seems to exist an optimal treating temperature to obtain the maximum efficiency, as the absorbing efficiency first increases, and then decreases, with the increase in treatment temperature. Therefore, this study enriches our knowledge and understanding microwave absorption from TiO2-based nanomaterials which may inspire new ideas on other systems to enhance their performance as well.

关键词： Hydrogenation Reflection loss Permittivity Permeability Microwave absorption

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Characteristics of Suspended Particulate Matter and the Coastal Turbidity Maximum Areas of the Mekong River

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Journal of Environmental Science and Engineering(A) 2015年第2期4卷 67-78页

作者： Vu Duy vinh tran Anh Tu tran Dinh Lan Nguyen Ngoc Tien Institute of Marine Environment and Resources Vietnam Academy of Science and Technology Haiphong 35999 Vietnam Institute of Marine Geology and Geophysics Vietnam Academy of Science and Technology Hanoi 10999 Vietnam

This paper presents the results of application of a 3D （three-dimensional） numerical model to study on MTZ （maximum turbidity zone） in the coastal zone of Mekong River Delta. In this study, a 3D system model with combination of hydrodynamics--wave and suspended sediment transport was set up and validated with measured data in the study area. Based on calculated scenarios for the flood and the dry season, the results have shown appearance of MTZs in the coastal zone of Mekong River with suspended sediment concentration prevalent of 0.04-0.07 kg·m^3 （the dry season） and 0.05-0.1kg·m^3 （the flood season）. The position and MTZs scale change with the interaction between fresh water and tidal oscillations. The MTZ occur more in the dry seasons compared to the wet season. The MTZs are prevalent located far away from estuaries about in 12-22 km （in the dry season）, and 5-15 km in the flood season.

关键词： Modelling maximum turbidity zone suspended sediment transport Me Kong river coastal area.

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Optimization, equilibrium, adsorption behavior and role of surface functional groups on graphene oxide-based nanocomposite towards diclofenac drug

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Journal of Environmental Sciences 2020年第7期32卷 137-150页

作者： Thuan van tran Duyen Thi Cam Nguyen Hanh TNLe Dai-Viet NVo Sonil Nanda Trinh Duy Nguyen Nguyen Tat Thanh Hi-Tech Institute Nguyen Tat Thanh UniversityHo Chi Minh City 755414Viet Nam Center of Excellence for Green Energy and Environmental Nanomaterials(CE@GrEEN) Nguyen Tat Thanh UniversityHo Chi Minh City 755414Viet Nam Institute of Hygiene and Public Health Ho Chi Minh City 700000Viet Nam Department of Chemical and Biochemical Engineering University of Western OntarioLondonOntarioCanada

Aquatic contamination of diclofenac(DCF),an emergent non-steroidal anti-inflammatory drug(NSAIDs),can result in adverse effects to many ecosystems through ***,introducing effective remediation techniques to sequester the pharmaceutical wastes is highly fundamental to prevent their accumulation in the ***,adsorption has been presented as a green and efficient ***,we report the characterization and application of the novel magnetic nanocomposite(GO@CoFe2O4)derived from cobalt-based ferrite(CoFe2O4)and graphene oxide(GO)for DCF *** the optimization procedure,the response surface methodology(RSM)was adopted to investigate the impacts of DCF concentration(1.6-18.4 mg/L),DCF dosage(0.08-0.92 g/L),and solution pH(2.6-9.4)to find the optimum conditions for DCF removal,at 10.5 mg/L,0.74 g/L,and pH 4,*** the adsorption experiments,the kinetic,isotherm,thermodynamic,and intraparticle diffusion models were systematically ***,we have elucidated the role of functional groups on the surface of GO@CoFe2O4 in enhancing the adsorption of DCF *** good removal efficiency(up to 86.1%),high maximum adsorption capacity(32.4 mg/g),GO@CoFe2O4 can be a potential candidate to eliminate DCF drug from water.

关键词： Diclofenac sodium Graphene oxide Magnetic nanocomposite Response surface methodology Pharmaceuticals adsorption

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胡志明市—中梁高速公路某路桥过渡段动态响应及坡稳定性分析

胡志明市—中梁高速公路某路桥过渡段动态响应及坡稳定性分析

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作者： tran HUU vinh（陈友永）北京交通大学

学位级别：硕士

随着科技的不断发展,越南高速公路也得到前所未有的发展,方便、舒适、快捷已经成为目前高速公路的最大优点。唯一美中不足的是高速公路路桥过渡段不均匀沉降得不到很好的处理,时常出现跳车现象,从而影响行车速度和乘客的舒适程度,也为... 详细信息

随着科技的不断发展,越南高速公路也得到前所未有的发展,方便、舒适、快捷已经成为目前高速公路的最大优点。唯一美中不足的是高速公路路桥过渡段不均匀沉降得不到很好的处理,时常出现跳车现象,从而影响行车速度和乘客的舒适程度,也为行车安全带来很大隐患。路桥过渡段是设计和施工中的薄弱环节,但长期以来,对采用哪种过渡段设置方法较为合理,至今仍未达成完全的共识。本论文通过讨论了越南公路交通系统和路基以及公路路桥过渡段的现状与缺点,针对越南胡志明市-中梁高速公路位于KM27+260的过渡段,分析桥头跳车的现象和原因,并使用ABAQUS/CAE为工作平台建立了数值模型,进行静态模拟分析与动态模拟分析,主要研究分析影响路桥过渡段平顺性的主要因素,并己取得了一些有价值的结论。通过比较和分析不同过渡段填土的弹性模量参数的弯沉结果,总结了过渡段沉降的发展规律,分析了如何设计最优的倒梯形形式的过渡段,从而减小差异沉降,消除桥头跳车现象。最后,对该路桥过渡段在越南特有的强降雨条件下进行降雨入渗对路基边坡的稳定性分析。这些研究结果将对越南高速公路过渡段设计有借鉴的意义。

关键词：高速公路路桥过渡段差异沉降降雨安全系数 ABAQUS数值计算

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Detection and localization of the hemoglobin and collagen distribution of the uterine cervix

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Journal of Innovative Optical Health Sciences 2019年第4期12卷 116-126页

作者： tran van Tien Nguyen Ngoc Quynh Le Huynh Duc Phan Ngoc Khuong Cat Huynh Quang Linh Department of Applied Physics Faculty of Applied Science Ho Chi Minh City University of Technology700000 Vietnam DCSELAB—National key Laboratory of Digital Control and System Engineering 700000 Vietnam Department of Biomedical Engineering Faculty of Medicine Nguyen Tat Thanh University700000 Vietnam Department of Engineering Physics Faculty of Applied Science Ho Chi Minh City University of Technology700000 Vietnam

Changes of the blood vessels and collagen are associated with the development of abnormal cervical ***,optical coberence tomography and Mueller polarization images were 1used to provide information regarding the presence of collagen fibers in the cervical ***,most of these methods need a lot of time for image recording and are *** addition,the general survey on the absorption and distribution characteristics of collagen and blood in the cervical is still *** this study,we developed a colposcopy combining cross-polarized inage and image procssing algorithm with an fficient analytical model to map the distribution of blood and collagen in the *** this system's proof of concept,we captured and processed the case of cervical ectopy and Nabothian *** results show that the distribution of blood and collagen maps matched with anatomical and physiological when compared with Lugol's iodline *** technology has some advantages,such as low cost,real time,and can replace the 11se of acetic acid or Lugol's iodine in the future.

关键词： Hemoglobin collagen cross polarized image uterine cervix

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