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Improved flood susceptibility mapping using a best first decision tree integrated with ensemble learning techniques

Geoscience Frontiers 2021年第3期12卷 333-342页

作者： Binh Thai Pham Abolfazl Jaafari tran van Phong Hoang Phan Hai Yen tran Thi Tuyen Vu van Luong Huu Duy Nguyen Hiep van Le Loke Kok Foong University of transport Technology Ha Noi 100000Viet Nam Research Institute of Forests and Rangelands Agricultural ResearchEducation and Extension Organization(AREEO)TehranIran Institute of Geological Sciences Vietnam Academy of Sciences and Technology84 Chua Lang StreetDong daHa NoiViet Nam Department of Geography School of Social EducationVinh UniversityViet Nam Department of Resource and Environment Management School of Agriculture and ResourcesVinh UniversityViet Nam Faculty of Geography VNU University of Science334 Nguyen TraiHa NoiViet Nam Institute of Research and Development Duy Tan UniversityDa Nang 550000Viet Nam Department for Management of Science and Technology Development Ton Duc Thang UniversityHo Chi Minh CityViet Nam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh CityViet Nam

Improving the accuracy of flood prediction and mapping is crucial for reducing damage resulting from flood *** this study,we proposed and validated three ensemble models based on the Best First Decision Tree(BFT)and the Bagging(Bagging-BFT),Decorate(Bagging-BFT),and Random Subspace(RSS-BFT)ensemble learning techniques for an improved prediction of flood susceptibility in a spatially-explicit manner.A total number of 126 historical flood events from the Nghe An Province(Vietnam)were connected to a set of 10 flood influencing factors(slope,elevation,aspect,curvature,river density,distance from rivers,flow direction,geology,soil,and land use)for generating the training and validation *** models were validated via several performance metrics that demonstrated the capability of all three ensemble models in elucidating the underlying pattern of flood occurrences within the research area and predicting the probability of future flood *** on the Area Under the receiver operating characteristic Curve(AUC),the ensemble Decorate-BFT model that achieved an AUC value of 0.989 was identified as the superior model over the RSS-BFT(AUC=0.982)and Bagging-BFT(AUC=0.967)models.A comparison between the performance of the models and the models previously reported in the literature confirmed that our ensemble models provided a reliable estimate of flood susceptibilities and their resulting susceptibility maps are trustful for flood early warning systems as well as development of mitigation plans.

关键词： Machine learning Ensemble learners Hybrid modeling

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Static analysis of corrugated panels using homogenization models and a cell-based smoothed mindlin plate element (CS-MIN3)

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 251-272页

作者： Nhan NGUYEN-MINH Nha tran-van Thang BUI-XUAN Trung NGUYEN-THOI Faculty of Applied Science Bach Khoa University (BKU)Ho Chi Minh CityVietnam Faculty of Mathematics and Computer Science Ho Chi Minh City University of Science (HCMUS)Ho Chi Minh CityVietnam Department of Mathematics L ouisiana State UniversityBaton RougeLA 70803USA Division of Computational Mathematics and Engineering Institute of Computational ScienceTon Due Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Due Thang UniversityHo Chi Minh CityVietnam

Homogenization is a promising approach to capture the behavior of complex structures like corrugated panels. It enables us to replace high-cost shell models with stiffness-equivalent orthotropic plate alternatives. Many homogenization models for corrugated panels of different shapes have been proposed. However, there is a lack of investigations for verifying their accuracy and reliability. In addition, in the recent trend of development of smoothed finite element methods, the cell-based smoothed three-node Mindlin plate element (CS-MIN3) based on the first-order shear deformation theory (FSDT) has been proposed and successfully applied to many analyses of plate and shell structures. Thus, this paper further extends the CS-MIN3 by integrating itself with homogenization models to give homogenization methods. In these methods, the equivalent extensional, bending, and transverse shear stiftriess components which constitute the equivalent orthotropic plate models are represented in explicit analytical expressions. Using the results of ANSYS and ABAQUS shell simulations as references, some numerical examples are conducted to verify the accuracy and reliability of the homogenization methods for static analyses of trapezoidally and sinusoidally corrugated panels.

关键词： homogenization corrugated panel asymptotic analysis smoothed finite element method (S-FEM) cell-based smoothed three-node Mindlin plate element (CS-MIN3)

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On-shell mediator dark matter models and the Xenon1T excess

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Chinese Physics C 2021年第1期45卷 155-161页

作者： Mingxuan Du Jinhan Liang Zuowei Liu van Que tran Yilun Xue Department of Physics Nanjing UniversityNanjing 210093China Center for High Energy Physics Peking UniversityBeijing 100871China Nanjing Proton Source Research and Design Center Nanjing 210093China CAS Center for Excellence in Particle Physics Beijing 100049China

We present a dark matter model to explain the excess events in the electron recoil data recently reported by the Xenon1 T experiment. In our model, dark matter χ annihilates into a pair of on-shell particles Φ, which subsequently decay into the ψψ final state;ψ interacts with electrons to generate the observed excess events. Because of the mass hierarchy, the velocity of ψ can be rather large and can have an extended distribution, providing a good fit to the electron recoil energy spectrum. We estimate the flux of ψ from dark matter annihilations in the galaxy and further determine the interaction cross section, which is sizable but sufficiently small to allow ψ to penetrate the rocks to reach the underground labs.

关键词： particle dark matter Xenon IT new physics

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Mechanical characteristics of tensile strength ratio method compared to other parameters used for moisture susceptibility evaluation of asphalt mixtures

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Journal of Traffic and transportation Engineering(English Edition) 2019年第6期6卷 621-630页

作者： Thanh Chung Do van Phuc tran van Phuc Le Hyun Jong Lee Won Jae Kim Department of Civil and Environmental Engineering Sejong UniversitySeoul 143-747South Korea Faculty of Civil Engineering University of Transport and CommunicationsHo Chi Minh CityVietnam

In this study,mechanical characteristics of tensile strength ratio(TSR)were evaluated by comparing it to other methods in evaluating moisture sensitivity of asphalt *** types of asphalt mixtures with and without anti-stripping additives were prepared and tested in the *** compressive strength(UCS)and indirect tensile(IDT)testing were conducted to determine the mixture’s tensile strength ratio and cohesion ratio(CR).Determining TSR alone was found to be insufficient when evaluating moisture *** is a need to consider both TSR and wet IDT strength to properly evaluate moisture behavior of asphalt ***,it was found that the cohesion and the IDT strength have a good relation in which the minimum condition of the slope,must be ***,it was observed thatβvalues change depending on material type and ***,there is a need to evaluate theseβvalues for varying material and testing *** addition,it was found that the TSR and CR results are highly correlated with an average difference of 1.5%.Furthermore,other tests such as Marshall stability and dynamic immersion were also *** was found that Marshall stability ratio(MSR)and Marshall stability to flow ratio(MSFR)values are less sensitive to moisture effect when measuring moisture resistance compared to TSR ***,the 48 h testing result of the dynamic immersion test showed better correlation with TSR values.

关键词： Asphalt mixtures Moisture damage Anti-stripping additives Tensile strength ratio Cohesion strength ratio

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Synthesis and characterization of NaYF4:Yb3+,Er3+@silica-N=folic acid nanocomplex for bioimaginable detecting MCF-7 breast cancer cells

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Journal of Rare Earths 2019年第11期37卷 1183-1187页

作者： Ha Thi Phuong tran Thu Huong Le Thi vinh Hoang Thi Khuyen Do Thi Thao Nguyen Thanh Huong Pham Thi Lien Le Quoc Minh Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc VietCau GiayHanoiViet Nam Graduate University of Science and Technology-Vietnam Academy of Science and Technology 18 Hoang Quoc VietCau GiayHanoiViet Nam Department of Chemistry Hanoi Medical University1-Ton That TungDong DaHanoiViet Nam Department of Chemistry Hanoi University of Mining and Geology18-Pho LienBac Tu LiemHanoiViet Nam Institute of Biotechnology Vietnam Academy of Science and Technology18-Hoang Quoc VietCau GiayHanoiViet Nam Duy Tan University K7/25 Quang TrungDa NangViet Nam

Upconversion nanophosphors are new promising nanomaterials to be used as biolabels for detection and imaging of cancer *** nanophosphors absorb long-wavelength excitation radiation in the infrared or near infrared region and emit shorter wavelength,higher energy radiation from ultraviolet to *** this paper,we studied the hydrothermal method and optical properties of the functionalized NaYF4:Yb^3+,Er^3+for biomedical *** synthesis,these NaYF4:Yb^3+,Er^3+nanophosphors were functionalized with aminosilanes and folic *** acid binds to the folate receptor on the surface of MCF-7 breast cancer cells and this binding promotes internalization of the nanophosphors via *** sizes of the functionalized NaYF4:Yb^3+,Er^3+@silica-N=FA(folic acid)nanophosphors can be controlled with length of the rod about 300-800 nm and diameter of the rod about 100-200 *** structure of NaYF4:Yb^3+,Er^3+is in hexagonal crystal *** photo luminescence(PL)spectra of the functionalized NaYF4:Yb^3+,Er^3+@silica-N=FA nanophosphors were *** nanophosphors emit in red color with the strongest band at 650 nm under 980 nm *** result can provide NaYF4:Er^3+,Yb^3+@silica-N=FA complex for developing fluorescence label and image tool in cancer biology and medicine.

关键词： Upconversion luminescence NaYF4:Yb^3+,Er^3+ Nanophosphors Bioimaging Cancer cell Rare earths

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Effects of Foods on Maturity and Spawning Induction Methods on Ovulation of Rice Field Eel Monopterus albus(Zuiew,1793)in Thua Thien Hue Province,Vietnam

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Journal of Agricultural Science and Technology(A) 2017年第B10期7卷 85-92页

作者： tran vinh Phuong Nguyen van Khanh Pham Thi Hai Yen Vo Dieu Nguyen van Huy Institute of Biotechnology Hue UniversityPhu ThuongPhu VangThua Thien Hue 530000Vietnam Faculty of Fisheries University of Agriculture and ForestryHue University102 Phung Hung StreetHue 530000Vietnam

Adult rice field eels with 125.52±27.99 g body weight corresponding to 44.79±5.93 cm in length were maturity cultured in a 5 m^2 cement tank without mud for three months with density 30 eels/m^*** broodstocks were fed with three types of food including:sea fish(T1),commercial pellet food(T2)and mixed food—50%sea fish and 50%commercial pellet food(T3).Result showed that the maximum gonadosomatic index(GSI)of female eels fed by sea fish(2.89%±0.67%)was higher than both commercial pellet food(1.62%±0.62%)and mixed food(2.03%±0.82%)(P0.05).Maturity rate of female fed by sea fish(88.91%±9.64%)was higher than commercial pellet food(61.12%±9.64%)(P0.05).*** eels were induced for spawning with two kinds of hormones,including T1:human chorionic ganadotropin(HCG)at 1,500 IU/kg,T2:luteinzing hormone-releasing hormone(LHRH-a)at 150μg/kg and domperidon 10 mg/kg,and T3:control without *** results of spawning induction methods showed that the reproduction rate of female eels induced by LHRH-a and HCG hormones were higher than that by natural reproduction method(P<0.05).Others,the survival rate of fry eels after 5 d using natural reproduction method(92.65%±2.54%)was higher than both using LHRH-a(67.77%±1.91%)and HCG(68.65%±1.23%)hormones(P<0.05).The average diameter of eggs was 3.40-3.41 mm and the length of newly hatched eels was 1.72±0.19 cm.

关键词： Food maturity culture ovulation spawing induction method rice field eel

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Introduction to the China-Vietnam Cooperation Project: A Comparative Study of the Holocene Sedimentary Evolution of the Yangtze and Red River Deltas

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Journal of Ocean University of China 2018年第6期17卷 1269-1271页

作者： YIN Ping PHUNG van Phach tran Dinh Lan DO Huy Cuong BUI van Vuong DUAN Xiaoyong Key Laboratory of Marine Environmental Geology Ministry of Natural Resources Qingdao Institute of Marine Geology Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology Institute of Marine Geology and Geophysics Vietnam Academy of Science and Technology Institute of Marine Environment and Resources Vietnam Academy of Science and Technology

Both China and Vietnam confront the challenges of natural geohazards and environmental changes in their deltas and coastal zones due to rapid urbanization, economic development, and the impacts of global climate change. China and Vietnam initiated a comparative study of the Holocene sedimentary evolution of the Yangtze River Delta(YRD) and Red River Delta(RRD) for the period 2015–2018 in order to improve the understanding of the two delta evolution histories in the Holocene. Previous investigative data of the two rivers, onshore delta plains, and offshore subaqueous deltas have been explored and reinterpreted. New data gleaned from boreholes, piston cores, shallow seismic and hydrodynamic sources have been collected from the offshore YRD and the East China Sea inner shelf, and surface sediments and short cores have been collected from the RRD near-shore areas. Six focal areas of the joint project have been defined for comparative studies of the two deltas, including morphological development, sequential stratigraphy, coastline shifting, sedimentary characteristics, sedimentary dynamics, and correlation with anthropogenic global climate change. The results of these study areas are presented herein. The joint project also includes cooperative capacity building; exchanges of young scientists have been organized during the project period, and hands-on training in laboratory geochemical analysis, numerical modeling, and seismic data processing and interpretation have been provided by China and its Vietnamese geoscientist partners. Joint field excursions were organized to the upstream of the Yangtze and Red Rivers in Yunan Province, China, all the way downstream along the Vietnamese portion of the Red River. These joint studies have, over the past three years, improved understanding of the evolutionary history of these two major rivers and their mechanisms of source to sink. Joint project results of these two major deltas are not limited to the geosciences; the cooperativ

关键词： Yangtze River Delta Red River Delta Holocene sedimentary environment

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Study of vertically ascending flight of a hawkmoth model

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Acta Mechanica Sinica 2020年第5期36卷 1031-1045,I0002页

作者： Anh Tuan Nguyen Vu Dan Thanh Le The Hung tran V.N.Due van Binh Phung Faculty of Aerospace Engineering Le Quy Don Technical UniversityHanoiVietnam Institute of Theoretical and Applied Research.Duy Tan University HanoiVietnam Division of Construction Computation Institute for Computational ScienceTon Due Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Due Thang UniversityHo Chi Minh CityVietnam

This paper provides insight into the wing kinematics,the power requirement and the dynamic stability characteristics of a hawkmoth model in vertically ascending *** wing kinematics of the hawkmoth model is obtained based on the minimum required power *** optimization process is conducted using genetic and simplex algorithms that are coupled with an artificial neural network to rapidly predict the aerodynamic force and required *** training data for the neural network are generated from an unsteady vortex-lattice *** to hover,the results in this study show the larger flapping frequency and the smaller rotation amplitude of the hawkmoth wing kinematics in ascending ***,more power is required when the ascending speed *** conducting a dynamic modal analysis based on a cycle-average approach,the certain effect of the ascending speed on the modal structures of the hawkmoth model was observed.

关键词： Hawkmoth Ascending flapping flight-Genetic algorithm Artificial neural network Flight dynamic stability

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Ni Single Atoms and Ni Phosphate Clusters Synergistically Triggered Surface-Functionalized MoS_(2)Nanosheets for High-performance Freshwater and Seawater Electrolysis

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Energy & Environmental Materials 2022年第4期5卷 1340-1349页

作者： Min Sung Kim Duy Thanh tran Thanh Hai Nguyen van An Dinh Nam Hoon Kim Joong Hee Lee Department of Nano Convergence Engineering Jeonbuk National UniversityJeonju 54896Republic of Korea Department of Precision Engineering Graduate School of EngineeringOsaka University2-1Yamada-okaSuita 565-0871Japan Carbon Composite Research Center Department of Polymer-Nanoscience and TechnologyJeonbuk National UniversityJeonju 54896Republic of Korea

Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active *** this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and *** Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M *** results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption *** evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,*** present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.

关键词： bifunctional electrocatalyst freshwater and seawater electrolysis nickel phosphate clusters nickel single atoms surface-functionalized-MoS_(2)nanosheets

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Knowledge and attitude toward COVID-19 among healthcare workers at District 2 Hospital, Ho Chi Minh City

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Asian Pacific Journal of Tropical Medicine 2020年第6期13卷 260-265页

作者： Huynh Giao Nguyen Thi Ngoc Han tran van Khanh Vo Kim Ngan Vo van Tam Pham Le An Faculty of Public Health University of Medicine and Pharmacy at Ho Chi Minh CityVietnam Department of Infectious Diseases University Medical Center Ho Chi Minh CityVietnam Department of Scientific Research District 2 HospitalHo Chi Minh CityVietnam Department of Nursing District 2 HospitalHo Chi Minh CityVietnam Faculty of Nursing and Medical Technology University of Medicine Pham Ngoc Thach at Ho Chi Minh CityVietnam Center for the Training of Family Medicine Faculty of MedicineUniversity of Medicine and Pharmacy at Ho Chi Minh CityVietnam

Objective:To assess the knowledge and attitude toward coronavirus disease-2019(COVID-19)among healthcare workers at District 2 Hospital in Ho Chi Minh City(HCMC).Methods:A cross-sectional study was performed between January 2020 and February 2020 at District 2 Hospital.A systematic random sampling strategy was carried out and the data was collected through a self-administered questionnaire of the knowledge and attitude of healthcare workers regarding *** analysis was reported to describe the demographic,mean knowledge and attitude score of healthcare *** statistics including t-test,ANOVA and Spearman’s correlation were used to evaluate the relationship between study ***:A total of 327 eligible healthcare workers had a mean score of knowledge and attitude of 8.17±1.3(range 4-10)and 1.86±0.43(range 1-5),*** showed good knowledge and a positive ***,approximately two thirds of the participants knew the mode of transmission,the isolation period and treatment(67.0%,65.8%,and 58.4%,respectively),and 82.3%and 79.8%,respectively,held positive attitude regarding the risk of personal and family members getting *** was a negative correlation between knowledge scores and attitude scores(r=-0.21,P<0.001).Additionally,healthcare workerspredominately used social media to inform themselves about COVID-19(91.1%).Conclusions:The majority of healthcare workers had good knowledge and positive attitude toward ***,the level of some knowledge and attitude lower than that expected for their position level towards the *** education interventions and campaigns are required for healthcare workers.

关键词： Knowledge Attitude COVID-19 Healthcare worker District 2 Hospital

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