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Estimating Urban Households’ Willingness-to-Pay for Upland Forest Restoration in Vietnam

Open Journal of Forestry 2016年第3期6卷 191-198页

作者： quy van khuc Mustapha Alhassan John B. Loomis Trung Duc Tran Mark W. Paschke Department of Forest and Rangeland Stewardship Colorado State University Fort Collins CO USA Forestry Economics Research Center Vietnam Academy of Forest Science Hanoi Vietnam Department of Agricultural Economics University of Nebraska-Lincoln Lincoln NE USA Department of Agricultural and Resource Economics Colorado State University Fort Collins CO USA Department of Hydrology Meteorology & Oceanography Hanoi University of Science Hanoi Vietnam

Increased urbanization coupled with increased reliance of urban communities on rural areas for ecosystem service provision is a challenge faced by many nations. The ability of urban households to directly support restoration efforts in surrounding rural regions represents an underappreciated funding stream for ecological restoration. This study explored the willingness of urban households to support forest restoration in Vietnam. We surveyed 211 households (HHs) in the capital city Hanoi, Vietnam. A Maximum Likelihood Estimator (MLE) model allowed us to obtain the parameters of our model and quantify mean Willingness-to-Pay (WTP) for a program of forest restoration in addition to identifying factors influencing the decision of WTP. Generally, over forty percent of the households surveyed are willing to pay for forest restoration and the mean value of WTP is 37,830 VND ($1.73) per household per month. WTP depends on endogenous and exogenous factors including level of education, income, female-to-male ratio in the household, attitude toward payment for monthly electricity consumption, and awareness of payment for environmental service. Our results suggest that urban household’s demand for forest restoration is real, and represents an untapped source of restoration funding. Policy-makers should take actions to apply charges on water bills to turn this potential into reality for restoration projects in Vietnam if the benefits from restoration outweigh the costs based on our findings.

关键词： Willingness-to-Pay Households Forest Restoration U Minh Thuong National Park Vietnam

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Simulation of stabilizing process of dielectric nanoparticle in optical trap using counter-propagating pulsed laser beams

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Chinese Optics Letters 2010年第3期8卷 332-334页

作者： Ho Quang quy Mai van Luu Hoang Dinh Hai Donan Zhuang Institute of Applied PhysicsNEWTECHPRO Vietnam Academy of Science and Technology Faculty of PhysicsVinh University Pedagogical College of Nghean Department of PhysicsKing Mingkut's University of Technology Thonburi

The stabilizing process of glass particle in water by optical trap using the pulsed counter-propagating Gaussian beams is investigated. The influence of the optical power and the particle dimension on the rate and tim... 详细信息

关键词： Simulation of stabilizing process of dielectric nanoparticle in optical trap using counter-propagating pulsed laser beams

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Prediction of Shear Bond Strength of Asphalt Concrete Pavement Using Machine Learning Models and Grid Search Optimization Technique

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 691-712页

作者： quynh-Anh Thi Bui Dam Duc Nguyen Hiep van Le Indra Prakash Binh Thai Pham Civil Engineering Department University of Transport Technology54 Trieu KhucThanh XuanHanoi100000Vietnam DDG(R)Geological Survey of India Gandhinagar382010India

Determination of Shear Bond strength(SBS)at interlayer of double-layer asphalt concrete is crucial in flexible pavement *** study used three Machine Learning(ML)models,including K-Nearest Neighbors(KNN),Extra Trees(ET),and Light Gradient Boosting Machine(LGBM),to predict SBS based on easily determinable input ***,the Grid Search technique was employed for hyper-parameter tuning of the ML models,and cross-validation and learning curve analysis were used for training the *** models were built on a database of 240 experimental results and three input variables:temperature,normal pressure,and tack coat *** validation was performed using three statistical criteria:the coefficient of determination(R2),the Root Mean Square Error(RMSE),and the mean absolute error(MAE).Additionally,SHAP analysis was also used to validate the importance of the input variables in the prediction of the *** show that these models accurately predict SBS,with LGBM providing outstanding ***(Shapley Additive explanation)analysis for LGBM indicates that temperature is the most influential factor on ***,the proposed ML models can quickly and accurately predict SBS between two layers of asphalt concrete,serving practical applications in flexible pavement structure design.

关键词： Shear bond asphalt pavement grid search optimization machine learning

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Discrete-time sliding mode control with power rate exponential reaching law of a pneumatic artificial muscle system

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Control Theory and Technology 2022年第4期20卷 514-524页

作者： quy-Thinh Dao Trung-Kien Le Tri van-Anh Nguyen Manh-Linh Nguyen School of Electrical and Electronic Engineering Hanoi University of Science and TechnologyDai Co VietHanoi 11615Vietnam

This paper develops a discrete-time sliding mode controller with a power rate exponential reaching law approach to enhance the performance of a pneumatic artificial muscle system in both reaching time and chattering *** proposed method dynamically adapts to the variation of the switching function,which is based on an exponential term and a power rate term of the sliding ***,the controlled system can achieve high tracking performance while still obtain chattering-free ***,the effectiveness of the proposed method is validated through multiple experimental tests,focused on a dual pneumatic artificial muscle ***,experimental results show the effectiveness of the proposed approach in this paper.

关键词： Pneumatic artificial muscle Discrete-time sliding mode control Exponential reaching law Chattering

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Orange G degradation by heterogeneous peroxymonosulfate activation based on magnetic MnFe_(2)O_(4)/α-MnO_(2) hybrid

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Journal of Environmental Sciences 2023年第2期124卷 379-396页

作者： Le Thi Thao To van Nguyen van quy Nguyen Ngoc Man Phan Ki Jae Kim Nguyen Nhat Huy Nguyen Trung Dung Faculty of Physical and Chemical Engineering Le Quy Don Technical UniversityHanoi 100000Vietnam Department of Energy Engineering Konkuk UniversitySeoul 05029Korea School of Chemical Engineering College of EngineeringSungkyunkwan UniversityJangan-guSuwon 16419Korea Faculty of Environment and Natural Resources Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam Vietnam National University Ho Chi Minh City Linh Trung WardThu Duc CityHo Chi Minh City 700000Vietnam

Wastewater containing an azo dye Orange G(OG)causes massive environmental pollution,thus it is critical to develop a highly effective,environmental-friendly,and reusable catalyst in peroxymonosulfate(PMS)activation for OG *** this work,we successfully applied a magnetic MnFe_(2)O_(4)/α-MnO_(2) hybrid fabricated by a simple hydrothermal method for OG removal in *** characteristics of the hybrid were investigated by Xray diffraction,scanning electron microscopy,energy-dispersive X-ray spectroscopy,Fourier transform infrared spectroscopy,Brunauer–Emmett–Teller method,vibrating sample magnetometry,electron paramagnetic resonance,thermogravimetric analysis,and X-ray photoelectron *** effects of operational parameters(i.e.,catalytic system,catalytic dose,solution pH,and temperature)were *** results exhibited that 96.8% of OG degradation was obtained with MnFe_(2)O_(4)/α-MnO2(1:9)/PMS system in 30 min regardless of solution pH ***,the possible reaction mechanism of the coupling system was proposed,and the degradation intermediates of OG were identified by mass *** radical quenching experiments and EPR tests demonstrated that SO_(4)•̶,O_(2)•̶,and 1O2 were the primary reactive oxygen species responsible for the OG *** hybrid also displayed unusual stability with less than 30%loss in the OG removal after four sequential ***,magnetic MnFe2O4/α-MnO2 hybrid could be used as a high potential activator of PMS to remove orange G and maybe other dyes from wastewater.

关键词： MnFe_(2)O_(4)/α-MnO_(2) Peroxymonosulfate Orange G Catalytic degradation Reusability

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注化学剂驱油数值模拟(应用部分)

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石油学报 1989年第3期 68-76页

作者：袁士义 N. van quy 法国石油研究院石油勘探开发科学研究院

本文利用在上部分(《石油学报》1988第一期)中建立的化学驱组分模型,对多种情况下的化学驱油算例进行了模拟计算。首先与实验结果进行了比较,计算结果与实验结果取得了较好的一致性,表明了模型描述实际问题的能力及正常的工作性能;进而... 详细信息

本文利用在上部分(《石油学报》1988第一期)中建立的化学驱组分模型,对多种情况下的化学驱油算例进行了模拟计算。首先与实验结果进行了比较,计算结果与实验结果取得了较好的一致性,表明了模型描述实际问题的能力及正常的工作性能;进而对现场条件下的驱替试验例子进行了模拟预测,并对各种因素(如表面活性剂段塞组分与尺寸,注入速度,活性剂的扩散、吸附,重力,油藏非均质性,流体压缩性,注采方式等)对驱油特性的影响作用进行了分析研究,给出了各自的影响效应。模型的使用表明,它对于各种机理性研究.现场试验特性预测,方案的可行性研究,各种参数的优化选择,驱替方案的制订等将是一个非常有用的工具。

关键词：段塞聚合物溶液表面活性剂驱替油藏注化学剂高分子溶液非牛顿流体水泥外加剂化学剂注入驱油特性化学驱提高采收率化学驱油原油采收率数值模拟数值方法

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Two Models of Optical Pulse Self-Compressor Combined the Nonlinear Coupler with Backward Raman Fiber Amplifier

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Journal of Electromagnetic Analysis and Applications 2012年第9期4卷 379-385页

作者： Quang quy Ho van Bien Chu NEWTECHPRO Vietnam Academy of Science and Technology Hanoi Vietnam Physical Faculty Hongduc University Than- hhoa Vietam

Based on the nonlinearity of the nonlinear optical coupler (NOC) and the amplifying capacity of the backward Raman fiber amplifier (PBRFA), two new optical systems to compress the optical pulse (Optical Pulse Self-Compressor: OPSC) are proposed. Using the expressions describing relationship between input and output intensities from ports of the NOC and the derived expression describing the amplification of the PBRFA, the compressing process of the optical pulse propagating through the OPSC is simulated. The results show that the peak of the optical pulse will be enhanced and the duration of the optical pulse will be reduced significantly. Consequently, the shape of input pulse is completely compressed with the certain efficiency. It means the optical pulse is self-compressed without the external pump pulse by proposing the OPSC.

关键词： Intelligent Transportation System Microstrip Phased Array Antenna Tchebyscheff Polynomial Electromagnetic Interference

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Optical Trap 2D Array by Acoustic Modulation

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Journal of Physical Science and Application 2014年第7期4卷 420-425页

作者： van Thinh Nguyen Quang quy Ho Physics Faculty Bac Lieu University Bac Lieu Vietnam Institute of Applied Physics NEWTECHPRO VAST 8 Hoang Quoc Viet Hanoi Vietnam

In this artilce a new optical trap 2D array by the acoustic modulation is proposed. Based on the ＂called＂ acoustic-elasticity of the fluid embedding trapped microparticle, the expression describing the refractive index induced by cross-interference of two perpendicular ultrasonic waves is approximately derived. By simulation, the 2D array of the Graded-refractive index lenses appeared in the fluid layer with certain strain-acoustic constant and thickness. The trapping capability of the plane-wave laser beam propagating through those lenses is shown out, and the appearance of the optical trap 2D array has been affirmed.

关键词： Optical trap array acoustic modulation microlens.

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Influence of the Kerr Effect on the Optical Force Acting on the Dielectric Particle

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Journal of Physical Science and Application 2012年第10期2卷 414-419页

作者： Quang quy Ho van Nam Hoang NEWTECHPRO Vietnam Academy of Science and Technology Hanoi Vietnam Council of Science and Technology Hatinh Vietnam

Basing on the necessary condition for the trapping dielectric particle by the Gaussian beam, the Kerr effect in the tweezers with the nonlinear particle or the nonlinear medium is proposed to concern. The expressions of the optical forces concerned with the Kerr effect, which affects the refractive index of the medium, are presented. The distribution of the optical forces in the trapping region is simulated and discussed. The results show that the stability of the tweezers depends on the nonlinear coefficient of refractive index, and the optical tweezers could be broken down with a critical value of the nonlinear coefficient of refractive index of the surrounding medium, or with a critical value of the laser intensity, duration of laser pulse, and radius of beam waist. Moreover, these results give us the explanation the stability of the optical tweezers used for the trapped object as biological molecule embedded in the fluid, which is sensitive with Kerr effect.

关键词： Optical tweezers optical force Kerr effect nonlinear medium.

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Upconversion luminescence of Gd2O3:Er3+and Gd2O3:Er3+/silica nanophosphors fabricated by EDTA combustion method

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Journal of Rare Earths 2019年第11期37卷 1126-1131页

作者： Le Quoc Minh Tran Kim Anh Nguyen Duy Hung Pham Thi Minh Chau Nguyen Thi quy Hai Ho van Tuyen Vu Thi Thai Ha Vu Duc Tu Wieslaw Strek Institute of Theoretical and Applied Research Duy Tan UniversityDa Nang 55000Viet Nam Advanced Institute for Science and Technology Hanoi University of Science and Technology1 Dai Co VietHai Ba TrungHanoiViet Nam Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadCau Giay DistrictHanoiViet Nam Institute of Low Temperature and Structure Research Polish Academy of Science 2 OkolnaWroclawPoland

Gd2O3:Er^3+nanophosphors were fabricated by the combustion method in presence of Na2 ethylene diamine tetra acetic acid(EDTA-Na2)as fuel at not high temperature(≤350℃)within a very short time of 5 *** added concentration of Er^3+ions in Gd2O3 matrix was changed from 0.5 mol%to 5.0 mol%.The X-ray diffraction pattern of samples indicates the monoclinic structure of Gd2O3:Er^3+.The morphology and chemical composition analysis of the Gd2O3:Er^3+samples are characterized by a field emission scanning electron microscope(FESEM)and a Fourier-transform infrared spectrometer(FTIR).The photoluminescence(PL),photo luminescence excitation(PLE)and upconversion(UC)at room temperature of the prepared materials with different concentrations of Er^3+were *** PL of Gd2O3:Er^3+nanomaterials are shown in visible at 545,594,623,648,688 nm under excitation at 275 *** emission bands from transitions of Er^3+from 2P3/2 to 4F9/2 are observed,UC luminescent spectra of the Gd2O3:Er^3+/silica nanocomposites under 976 nm excitation show the bands at 548 and 670 *** influence of excitation power at 980 nm for transitions were measured and *** results indicate that the upconversion process of Gd2O3:Er^3+/silica is two photons absorption *** low temperature dependence of UC luminescent intensities of the main bands of Gd2O3:Er^3+was investigated towards development of a nanotemperature sensor in the range of 10-300 K.

关键词： Upconversion luminescence Gd2O3:Er3+ Gd2O3:Er3+/silica Nanophosphors EDTA combustion Rare earths

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