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Effect of Land Use Change on Runoff and Sediment Yield in Da River Basin of Hoa Binh province, Northwest Vietnam

Journal of Mountain Science 2015年第4期12卷 1051-1064页

作者： NGO Thanh Son NGUYEN duy Binh Rajendra Prasad SHRESTHA Asian Institute of Technology Faculty of Land Resources Management Vietnam National University of Agriculture Faculty of Information Technology Vietnam National University of Agriculture

The objective of this study was to assess runoff discharge and sediment yield from Da River Basin in the Northwest of Vietnam using Soil and Water Assessment Tools(SWAT) *** SWAT model was calibrated and validated using the observed monthly stream flows and sediment yield at selected gauging *** results indicated that SWAT generally performs well in simulating runoff and sediment yield according to Nash-Sutcliffe efficiency(NSE), Observation's standard deviation ratio(RSR), and percent bias(PBIAS) *** runoff, the values of NSE, RSR, and PBIAS were 0.98,0.02, and 3.69 during calibration period and 0.99,0.01, and 1.56 during validation period, *** sediment yield, the efficiency was lower than the value of NSE, RSR, and PBIAS during calibration period were 0.81, 0.19, and-4.14 and 0.84, 0.16, and-2.56 during validation period, *** results of the study indicated that the vegetation status has a significant impact on runoff and sediment *** in land use type between 1995 and2005 from forest to field crop and urban strongly contributed to increasing the average annual runoff from 182.5 to 342.7 mm and sediment yield from101.3 to 148.1 ton-1 *** 2005 and 2010, adecrease of both runoff(from 342.7 to 167.6 mm) and sediment yield(from 148.1 to 74.0 ton-1 ha) was due to the expansion of forested area and application of soil conservation *** results of this study are important for developing soil and water conservation programs, extending future SWAT modelling studies and disseminating these results to other regions in Vietnam.

关键词： Land use change Hydrology Soil erosion Soil and Water Assessment Tools(SWAT) Da River Basin

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Constructing Collective Signature Schemes Using Problem of Finding Roots Modulo

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Computers, Materials & Continua 2022年第7期72卷 1105-1122页

作者： Tuan Nguyen Kim duy Ho Ngoc Nikolay A.Moldovyan School of Computer Science Duy Tan UniversityDa NangVietnam Department of Information Technology Ha NoiVietnam ITMO University St.PetersburgRussia

Digital signature schemes are often built based on the difficulty of the discrete logarithm problems,of the problem of factor analysis,of the problem of finding the roots modulo of large primes or a combination of the difficult problems mentioned *** this paper,we use the new difficult problem,which is to find the wth root in the finite ground field GF(p)to build representative collective signature schemes,but the chosen modulo p has a special structure distinct p=Nt_(0)t_(1)t_(2)+1,where N is an even number and t_(0),t_(1),t_(2) are prime numbers of equal magnitude,about 80 *** characteristics of the proposed scheme are:i)The private key of each signer consists of 2 components(K_(1),K_(2)),randomly selected,but the public key has only one component(Y)calculated by the formula Y=K_(w)^(1)_(1) K^(w)_(2)^(2);w_(1)=t_(0)t_(1) and w_(2)=t_(0)t_(2);and ii)The generated signature consists of a set of 3 components(e,S_(1),S_(2)).We use the technique of hiding the signer’s public key Y,which is the coefficientλgenerated by the group nanager,in the process of forming the group signature and representative collective signature to enhance the privacy of all members of the signing collective.

关键词： Computing roots finding roots modulo collective signature signing collective signing group

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Complementary doping of van der Waals materials through controlled intercalation for monolithically integrated electronics

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Nano Research 2020年第5期13卷 1369-1375页

作者： Ming Ke Huu duy Nguyen Hang Fan Man Li Huan Wu Yongjie Hu School of Engineering and Applied Science University of CaliforniaLos AngelesCalifornia 90095USA

Doping control has been a key challenge for electronic applications of van der Waals ***,we demonstrate complementary doping of black phosphorus using controlled ionic intercalation to achieve monolithic building *** characterize the anisotropic electrical transport as a function of ion concentrations and report a widely tunable resistivity up to three orders of magnitude with characteristic concentration dependence corresponding to phase transitions during *** a further step,we develop both p-type and n-type field effect transistors as well as electrical diodes with high device stability and *** addition,enhanced charge mobility from 380 to 820 cm^2/(V·s)with the intercalation process is observed and explained as the suppressed neutral impurity scattering based on our ab initio *** study provides a unique approach to atomically control the electrical properties of van der Waals materials,and may open up new opportunities in developing advanced electronics and physics platforms.

关键词： nanoelectronics two-dimensional(2D)materials and heterostructures FET diode tunable properties black phosphorus

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Free vibration analysis of laminated FG-CNT reinforced composite beams using finite element method

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 324-336页

作者： T.VO-duy V.HO-HUU T.NGUYEN-THOI Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Due Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Due Thang UniversityHo Chi Minh CityVietnam

In the present study, the free vibration of laminated functionally graded carbon nanotube reinforced composite beams is analyzed. The laminated beam is made of perfectly bonded carbon nanotubes reinforced composite (CNTRC) layers. In each layer, single-walled carbon nanotubes are assumed to be unifonnly distributed (UD) or functionally graded (FG) distributed along the thickness direction. Effective material properties of the two-phase composites, a mixture of carbon nanotubes (CNTs) and an isotropic polymer, are calculated using the extended nile of mixture. The first-order shear deformation theory is used to formulate a governing equation for predicting free vibration of laminated functionally graded carbon nanotubes reinforced composite (FG?CNTRC) beams. The governing equation is solved by the finite element method with various boundary conditions. Several numerical tests are perfbnned to investigate the influence of the CNTs volume fractions, CNTs distributions, CNTs orientation angles, boundary conditions, length-to-thickness ratios and the numbers of layers on the frequencies of the laminated FG-CNTRC beams. Moreover, a laminated composite beam combined by various distribution types of CNTs is also studied.

关键词： free vibration analysis laminated FG-CNTRC beam finite element method first-order shear deformation theory composite material

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Tail dependence in emerging ASEAN-6 equity markets: empirical evidence from quantitative approaches

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Financial Innovation 2020年第1期6卷 69-94页

作者： duy Duong Toan Luu Duc Huynh University of Economics Ho Chi Minh CityVietnam School of Banking University of Economics Ho Chi Minh City59C Nguyen Dinh Chieu StreetDistrict 3Ho Chi Minh CityVietnam

This study contributes a rich set of quantitative methodologies including a nonparametric approach(Chi-plots and K-plots)as well as copulas(traditional and timevarying with Student’s t-copulas)to the existing literature in terms of determining the dependence structure in ASEAN stock *** on the emerging ASEAN equity returns of six countries from January 2001 to December 2017,we found that Student’s t-copulas under time-varying approach is the most appropriate approach to explain these *** all research return pairs,the dependence between Vietnam and other ASEAN equity indices has the lowest ***,all couples show left-and right-tail dependence by each pair for pre-and postfinancial ***,diversification across these pairs of equity markets from ASEAN is still adequate for international investors,though it might trigger contagion risks.

关键词： ASEAN Stock indexes Chi-plots K-plots T-copulas Time-varying copulas

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Spatial prediction of rainfall-induced shallow landslides using hybrid integration approach of least-Squares Support Vector Machines and differential evolution optimization:a case study in Central Vietnam

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International Journal of Digital Earth 2016年第11期9卷 1077-1097页

作者： Dieu Tien Bui Binh thai Pham Quoc Phi Nguyen Nhat-Duc Hoang Geographic Information System Group Department of Business Administration and Computer ScienceUniversity College of Southeast NorwayBøi TelemarkNorway Faculty of Geomatics and Land Administration Hanoi University of Mining and GeologyHanoiVietnam Department of Civil Engineering Gujarat Technological UniversityAhmedabadGujaratIndia Department of Geotechnical Engineering University of Transport TechnologyHa NoiVietNam Department of Environmental Sciences Hanoi University of Mining and GeologyHanoiVietnam Faculty of Civil Engineering Institute of Research and DevelopmentDuy Tan UniversityDanangVietnam

This study represents a hybrid intelligence approach based on the differential evolution optimization and least-Squares Support Vector Machines for shallow landslide prediction,named as *** LSSVM is used to establish a landslide prediction model whereas the DE is adopted to search the optimal tuning parameters of the LSSVM *** this research,a GIS database with 129 historical landslide records in the Quy Hop area(Central Vietnam)has been collected to establish the hybrid *** receiver operating characteristic(ROC)curve and area under the curve(AUC)were used to assess the performance of the newly constructed *** results show that the proposed model has high performances with approximately 82%of AUCs on both training and validating *** model’s results were compared with those obtained from other methods,Support Vector Machines,Multilayer Perceptron Neural Networks,and J48 Decision *** result comparison demonstrates that the DE-LSSVMSLP deems best suited for the dataset at hand;therefore,the proposed model can be a promising tool for spatial prediction of rainfall-induced shallow landslides for the study area.

关键词： Shallow landslide least-Squares Support Vector Machines differential evolution GIS Vietnam

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Inorganic p-type semiconductors and carbon materials based hole transport materials for perovskite solar cells

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Chinese Chemical letters 2018年第8期29卷 1242-1250页

作者： Yang Yang Ngoc duy Pham Disheng Yao Huaiyong Zhu Prasad Yarlagadda Hongxia Wang School of Chemistry Physics and Mechanical Engineering Queensland University of Technology

Organic-inorganic lead halide based perovskite solar cells（PSCs） have presented a promising prospective in photovoltaic field with current record power conversion efficiency of 22.7%, which is comparable to commercial crystalline silicon cells and even higher than traditional thin film solar cells of CIGS. However,the pressure to enhance device stability under operational condition has driven researches towards development of stable hole transport materials（HTMs） for PSCs. Compared to traditional expensive organic HTMs such as spiro-OMeTAD, there is no doubt that inorganic p-type semiconductors and carbon materials are attractive alternatives that not only possess better stability but also are much cheaper. This review summarized the most recent progress of inorganic hole-transporting materials and carbon materials that have been developed for PSCs. The most recent advancement of device performance using these HTMs was demonstrated. In addition, the research of using various types of carbon materials as additives in HTMs to enhance device performance and stability or as electrical contact in HTM-free PSC was also demonstrated. The effectiveness of each type of materials on mitigating ion migration and degradation of PSC induced by humidity, illumination light intensity and high temperature is *** timely review sheds light on the approaches to tackle the stability issue of PSCs to push the technology towards commercialization through material engineering of HTM.

关键词： Perovskite Hole transport materials Inorganic p-type semiconductors Carbon materials Stability

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Hepatitis C virus genotype 6:Virology,epidemiology,genetic variation and clinical implication

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World Journal of Gastroenterology 2014年第11期20卷 2927-2940,1812页

作者： Vo duy Thong Srunthron Akkarathamrongsin Kittiyod Poovorawan Pisit Tangkijvanich Yong Poovorawan Center of Excellence in Clinical Virology Faculty of MedicineChulalongkorn UniversityBangkok 10330Thailand Department of Medicine Faculty of MedicineChulalongkorn UniversityBangkok 10330Thailand Department of Biochemistry Faculty of MedicineChulalongkorn UniversityBangkok 10330Thailand

Hepatitis C virus (HCV) is a serious public health problem affecting 170 million carriers worldwide. It is a leading cause of chronic hepatitis, cirrhosis, and liver cancer and is the primary cause for liver transplantation worldwide. HCV genotype 6 (HCV-6) is restricted to South China, South-East Asia, and it is also occasionally found in migrant patients from endemic countries. HCV-6 has considerable genetic diversity with 23 subtypes (a to w). Although direct sequencing followed by phylogenetic analysis is the gold standard for HCV-6 genotyping and subtyping, there are also now rapid genotyping tests available such as the reverse hybridization line probe assay (INNO-LiPA II; Innogenetics, Zwijnaarde, Belgium). HCV-6 patients present with similar clinical manifestations as patients infected with other genotypes. Based on current evidence, the optimal treatment duration of HCV-6 with pegylated interferon/ribavirin should be 48 wk, although a shortened treatment duration of 24 wk could be sufficient in patients with low pretreatment viral load who achieve rapid virological response. In addition, the development of direct-acting antiviral agents is ongoing, and they give high response rate when combined with standard therapy. Herein, we review the epidemiology, classification, diagnosis and treatment as it pertain to HCV-6.

关键词： Hepatitis C virus Genotype 6 Epidemiology Clinical Treatment

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Optimization method to suppress background for imaging multiple planes

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Journal of Innovative Optical Health Sciences 2019年第2期12卷 24-34页

作者： Vannhu le Department of Optical Engineering le Quy Don Technical University 236 Hoang Quoc Viet Street Tu Liem DistrictHanoiVietnam State Key Laboratory of Modern Optical Instrumentation College of Optical Science and Engineering Zhejiang University Hangzhou 310027P.R.China Institute of Research and Development duy Tan University Da Nang 550000Vietnam

3D live imaging is important for better understanding of biological *** obtain biological dynamic process,high imaging speed is *** order to improve speed in 3D live imaging,simultaneous imaging of multiple planes throughout a 3D volume has been ***,a main disadvantage of this method is the cross-talk from neighboring imaging *** this paper,we propose an optimization method to suppress background from neighboring imaging planes.A D-aperture is used to generate multiple light *** optimization method to suppress background is *** simulation results demonstrated that the proposed method can be used to suppress the effectiveness of background from neighboring light sheets.

关键词： Fluorescence microscopy imaging systems supper-resolution

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Improving the Dispersion and Integration of Multi-Walled Carbon Nanotubes in PolyvinyI-Alcohol Composite Thin Film through Surface Modification

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Journal of Chemistry and Chemical Engineering 2013年第1期7卷 18-25页

作者： Van Thang le T. Mirth Nguyet NGUYEN duy Vinh CAO Key Laboratory of Materials Technology Vietnam National University Ho Chi Minh City 70000 Vietnam Faculty of Materials Technology University of Technology Ho Chi Minh City 70000 Vietnam

The article investigated the influence of modification process parameters on dispersity of MWNTs DI （in deionized） water and PVA/MWNT composite＇s electrical conductivity. Experimental results obtained by SEM （scanning electron microscope）, TEM （transmission electron microscope）, transform Fourier infrared spectroscopy, pH meter confirmed the most effective conditions in modifying the MWNT surface at the 1：3 mixture of nitric and sulfuric acid at 60 ℃. The extinction coefficient value of functionalized MWNTs at 500 nm wavelength was determined to be 41.24 cm^2·mg^-1, while their dispersibility in DI water was about 12.85 mg/mL and stable in more than 3 weeks via UV-vis spectroscopy. The other important result is the decrease of volume resistivity from 7.98 × 10^6 MΩ·m ofPVA （polyvinyl alcohol） to 4.15 × 10^4 MΩ·m of PVA/1 wt% modified MWNT thin film.

关键词： MWNT modification composite

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