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Environmental and External Costs of Yali Hydropower Plant and Policy Recommendations in Vietnam

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Journal of Environmental Protection 2020年第4期11卷 344-358页

作者： nguyen Van Song Vu Ngoc Huyen nguyen Van Hanh nguyen xuan diep nguyen xuan Huu Pham Thanh Lan Ho Ngoc Cuong Do Thi diep Tran Thi Thu Trang nguyen Thi Minh Phuong Faculty of Economics and Rural Development (FERD) Vietnam National University of Agriculture (VNUA) Trauquy Gialam Hanoi Vietnam Viet Nam Institute of Energy (IEN) Hanoi Vietnam Thainguyen University of Economics & Business Administration (TNUEBA) Thainguyen Vietnam Vietnamese Academy of Forest Sciences (VAFS) Hanoi Vietnam Vinh University Vinh Vietnam

The purpose of this study is to estimate the monetary value of the main environmental and external costs of Yali Hydropower Plant (YHPP) and to incorporate them into the financial viability indices of the plant, namely its net present value and electricity price. The results were found that if the electricity price is kept at its original level of 5.2 US cents/kWh to cover direct costs only, the net present value of the plant would be reduced to about 27% by incorporating environmental and external costs. Alternatively, the electricity price would have to be increased to 5.68 US cents/kWh in order to cover the full costs of YHPP and to maintain the original net present value. The main policy recommendations are: Government regulations should require that the financial analysis and appraisal of all future electricity sources include the full cost of these schemes, including not only direct costs but also environmental and external costs related to preventing or mitigating the environmental impact caused by them. An appropriate financial mechanism should be established to allocate the revenue from full cost electricity pricing to a fund to cover the environmental protection and compensation costs.

关键词： Environmental and External Costs Hydro-Electricity Electricity Price Yali Hydropower

Landslide Susceptibility Mapping Using RBFN-Based Ensemble Machine Learning Models

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 467-500页

作者： Landslide Susceptibility Mapping Using RBFN-Based Ensemble Machine Learning Models Duc-Dam nguyen nguyen Viet Tiep Quynh-Anh Thi Bui Hiep Van Le Indra Prakash Romulus Costache Manish Pandey Binh Thai Pham Faculty of Civil Engineering University of Transport TechnologyThanh XuanHa Noi100000Vietnam Faculty of Hydraulic Engineering Hanoi University of Civil EngineeringHa Noi100000Vietnam DDG(R)Geological Survey of India Gandhinagar382010India Research Institute of the University of Bucharest Bucharest050663Romania National Institute of Hydrology and Water Management Bucharest013686Romania Department of Civil Engineering Transilvania University of BrasovBrasov500152Romania Danube Delta National Institute for Research and Development Tulcea820112Romania Marwadi University Research Center(MURC) Marwadi UniversityRajkotGujaratBharat360003India Department of Civil Engineering Faculty of Engineering&TechnologyMarwadi UniversityRajkotGujaratBharat360003India

This study was aimed to prepare landslide susceptibility maps for the Pithoragarh district in Uttarakhand,India,using advanced ensemble models that combined Radial Basis Function Networks(RBFN)with three ensemble learning techniques:DAGGING(DG),MULTIBOOST(MB),and ADABOOST(AB).This combination resulted in three distinct ensemble models:DG-RBFN,MB-RBFN,and ***,a traditional weighted method,Information Value(IV),and a benchmark machine learning(ML)model,Multilayer Perceptron Neural Network(MLP),were employed for comparison and *** models were developed using ten landslide conditioning factors,which included slope,aspect,elevation,curvature,land cover,geomorphology,overburden depth,lithology,distance to rivers and distance to *** factors were instrumental in predicting the output variable,which was the probability of landslide *** analysis of the models’performance indicated that the DG-RBFN model,with an Area Under ROC Curve(AUC)of 0.931,outperformed the other *** AB-RBFN model achieved an AUC of 0.929,the MB-RBFN model had an AUC of 0.913,and the MLP model recorded an AUC of *** results suggest that the advanced ensemble ML model DG-RBFN was more accurate than traditional statistical model,single MLP model,and other ensemble models in preparing trustworthy landslide susceptibility maps,thereby enhancing land use planning and decision-making.

关键词： Landslide susceptibility map spatial analysis ensemble modelling information values(IV)

Spectral properties of the surface reflectance of the northern polar region of Mercury

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Research in Astronomy and Astrophysics 2020年第3期20卷 92-107页

作者： nguyen Bich Ngoc Nicolas Bott Pham Ngoc diep Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18 Hoang Quoc VietCau GiayHanoiVietnam Laboratoire d'Etudes Spatiales et d' Instrumentation en Astrophysique l'Observatoire de Paris5 place Jules Janssen 92195 MeudonFrance

We analyze MESSENGER reflectance measurements covering the northern polar region of Mercury,the least studied region of the northern mercurian *** use observations from the Mercury Dual Imaging System Wide-Angle Camera(MDIS/WAC)and the Mercury Atmospheric and Surface Composition Spectrometer(MASCS/VIRS)to study the spectral dependence of the surface *** results obtained from the observations made by both instruments are remarkably *** find that a second degree polynomial description of the measured reflectance spectra gives very good fits to the data and that the information that they carry can best be characterized by two parameters,the mean reflectance and the mean relative spectral slope,averaged over the explored range of *** properties of the four main types of terrains known to form Mercury’s regolith in the northern region,smooth plains(SPs),heavily cratered terrain(HCT),fresh ejecta/materials and red pitted ground(RPG),are examined in terms of these two *** results are compared,and found consistent with those obtained by earlier studies in spite of difficulties met in obtaining accurate reflectance measurements under the large incidence angle condition characteristic of polar *** results will help with the preparation of the BepiColombo mission and with supporting its observational strategy.

关键词： planets and satellites terrestrial planets-planets and satellites surfaces-techniques spectroscopic

Liouvillian Solutions of Algebraic Ordinary Differential Equations of Order One of Genus Zero

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Journal of Systems Science & Complexity 2023年第2期36卷 884-893页

作者： nguyen Tri Dat NGO Lam xuan Chau Faculty of Basic Science Ho Chi Minh City University of TransportHo Chi Minh CityVietnam Department of Mathematics and Statistics Quy Nhon UniversityQuy Nhon CityVietnam

This paper considers the class of autonomous algebraic ordinary differential equations(AODEs)of order one,and studies their Liouvillian general *** particular,let F(y,w)=0 be a rational algebraic curve over *** authors give necessary and sufficient conditions for the autonomous first-order AODE F(y,y′)=0 to have a Liouvillian solution over ***,the authors show that a Liouvillian solutionαof this equation is either an algebraic function over C(x)or an algebraic function over C(exp(ax)).As a byproduct,these results lead to an algorithm for determining a Liouvillian general solution of an autonomous AODE of order one of genus *** parametrizations of rational algebraic curves play an important role on this method.

关键词： Algebraic ordinary differential equation autonomous differential equation Liouvillian solution rational algebraic curve rational parametrizations

Assessment by microsatellite analysis of genetic diversity and population structure of Enhalus acoroides from the coast of Khanh Hoa Province, Vietnam

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Acta Oceanologica Sinica 2019年第1期38卷 144-150页

作者： xuan-Vy nguyen Papenbrock Jutta Department of Marine Botany Institute of Oceanography Vietnam Academy of Science and Technology Graduate University of Science and Technology Institute of Botany Leibniz University Hannover

Seagrass beds degraded significantly since the last century on both, global and local scale. The seagrass species Enhalus acoroides(Linnaeus f.) Royle is a common species found in almost all marine ecosystems including bays,lagoons and around offshore islands in tropical regions of the West Pacific. It was shown that genetic diversity is an essential indicator of the conditions of ecosystems. In the present study, microsatellite markers were used to assess the genetic diversity and population structure of six distinct seagrass beds along the coast of the Khanh Hoa Province, Vietnam. The results indicate that the genetic diversity of the populations in the open sea is higher than in the lagoon. Seagrass beds occurring in disturbed sites show reduced genetic diversity. The fixing index value(FST) depicts a relatively high genetic structure among populations. Structure analysis clusters the populations into open sea and lagoon populations and cluster analysis and AMOVA indicate a significant difference between the two groups. There are low but non-significant positive correlations between geographic and genetic *** different habitats of the open sea and the lagoon are probably responsible for forming two groups.

关键词： Enhalus acoroides genetic diversity lagoon open sea population structure

Analysis and control of vibration of ropes in a high-rise elevator under earthquake excitation

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 447-460页

作者： Thuan xuan nguyen Nanako Miura Akira Sone Faculty of Mechanical Engineering Kyoto Institute Technology Matsugasaki

In this research, the vibration of elevator ropes, including the main rope and compensation rope are investigated simultaneously in a high-rise elevator system under earthquake excitation. Moreover, the paper presents a new control method to restrain the sway of both ropes. This study considers varying rope lengths during elevator operation which cause other system parameters such as natural frequency, and damping ratio to be time-variant variables. The dynamics of the ropes are analyzed by solving the governing non-stationary, nonlinear equation numerically. In order to mitigate the vibration of ropes in several motion conditions, particularly upwards movement, downward movement, stopped at the lowest position, and stopped at the highest position, an active equipment is installed at the compensation sheave. The stability of the system using the controller is analyzed at four states: without disturbance and static car, without disturbance and mobile car, including disturbance and static car, and including disturbance and mobile car. The efficiency of the controller used for dampening the vibration of elevator ropes is validated by numerical simulation results.

关键词： elevator ropes high-rise elevator vibration controller stability

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

EFFECT OF COMPOSITION AND PROCESSING CONDITION ON MICROSTRUCTURAL PROPERTIES AND DURABILITY OF FLUOROPOLYMER/ACRYLIC BLENDS

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Chinese Journal of Polymer Science 2009年第1期27卷 59-69页

作者： Derek L.Ho Forrest.A.Landis diep nguyen National Institute of Standards and Technology (NIST) GaithersburgMDUSA Pennsylvania State University YorkPAUSA Illinois Institute of Technology ChicagoILUSA

Fluoropolymer blends have been widely used as binders for exterior coatings because of their excellent resistance to ultra-violet (UV) radiation as well as to many corrosive chemical *** is known that the fluorinated component usually has a lower glass transition temperature and easily crystallizes in the final structure depending upon the blend composition and sample annealing *** investigated the effect of blend composition and annealing process (slow and fast cooling) on the surface morpho...

关键词： AFM Confocal microscopy Crystallinity Surface morphology Small angle scattering UV exposure

An analytical model for cross-Kerr nonlinearity in a four-level N-type atomic system with Doppler broadening

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Chinese Physics B 2022年第2期31卷 314-319页

作者： Dinh xuan Khoa nguyen Huy Bang nguyen Le Thuy An nguyen Van Phu Le Van Doai Vinh University 182 Le Duan StreetVinh CityVietna

We present an analytical model for cross-Kerr nonlinear coefficient in a four-level N-type atomic medium under Doppler *** model is applied to87 Rb atoms to analyze the dependence of the cross-Kerr nonlinear coefficient on the external light field and the temperature of atomic *** analysis shows that in the absence of electromagnetically induced transparency(EIT)the cross-Kerr nonlinear coefficient is zero,but it is significantly enhanced when the EIT is *** means that the cross-Kerr effect can be turned on/off when the external light field is on or ***,the amplitude and the sign of the cross-Kerr nonlinear coefficient are easily changed according to the intensity and frequency of the external light *** amplitude of the cross-Kerr nonlinear coefficient remarkably decreases when the temperature of atomic medium *** analytical model can be convenient to fit experimental observations and applied to photonic devices.

关键词： electromagnetically induced transparency Kerr nonlinear effect Doppler effect