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A novel approach for synthesis of hierarchical mesoporous Nd2O3 nanomaterials

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Journal of Rare Earths 2017年第7期35卷 677-682页

作者： Le Huu Trinh Dinh quang Khieu Hoang Thai Long Tran Thai Hoa Duong tuan quang nguyen Duc Cuong College of Sciences Hue University 77 Nguyen Hue Hue City Viet Nam Faculty of Hospitality and Tourism Hue University 22 Lam Hoang Hue CityViet Nam College of Education Hue University 34 Le LoL Hue City Viet Nam

A novel route to the fabrication of hierarchical mesoporous Nd_2O_3 nanostructures including nanospheres and nanoporous network was described. Their structure and morphology evolution of the as-synthesized materials were determined by various techniques such as scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, Fourier transforminfrared spectra, nitrogen adsorption/desorption isotherm, and a formation mechanism was proposed. The results revealed that the Nd_2O_3 nanospheres had the diameter of 300 nm, which were composed of small primary nanoparticles（NPs） with the size of 10 nm. The nanoporous structure also formed the NPs of ca. 10 nm which were connected with each other to form a three-dimensional（3D） texture. This simple and mild approach to fabricate hierarchical mesoporous Nd_2O_3 nanostructures could be easily scaled up and potentially extended to synthesize other oxide hierarchical structures.

关键词： Nd2O3 hierarchical nanostructures nanospheres nanoporous network rare earths

Analysis of Traffic Accidents in Vietnam

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World Journal of Engineering and Technology 2024年第3期12卷 522-528页

作者： Thi Yen nguyen Faculty of Transport Safety and Environment University of Transport and Communications Ha Noi Vietnam

Understanding the causes and solutions of road traffic accidents is important for developing road and action plans in a country. In Vietnam, awareness of traffic participants is the main cause of serious traffic accidents. In recent years, the number of road traffic accidents in Tuyen quang province with deaths has decreased, but the number of accidents has increased significantly. The article uses data on traffic accidents in Tuyen quang over the (2016-2023) has been analytically reviewed. From there, analyze accident characteristics and causes of traffic accidents in Tuyen quang province, and propose solutions to improve traffic safety in Tuyen quang, Vietnam. The findings can be information for managers and researchers interested in studying the province of Tuyen quang, Vietnam road traffic safety. Additionally, the findings have led the government to achieve national targets in reducing the number of accidents and serious injuries.

关键词： Traffic Safety Accident Cause Driver Behavior Human Factor Traffic Safety Policy

Effect of Poly-Alkylene-Glycol Quenchant on the Distortion, Hardness, and Microstructure of 65Mn Steel

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Computers, Materials & Continua 2021年第6期67卷 3249-3264页

作者： Thi Xuan Tran Xuan Phuong nguyen Duong Nam nguyen Dinh Toai Vu Minh quang Chau Osamah Ibrahim Khalaf Anh tuan Hoang Hanoi University of Science and Technology HanoiVietnam Ho Chi Minh City University of Transport Ho Chi Minh CityVietnam Vietnam Maritime University HaiphongVietnam Industrial University of Ho Chi Minh City(IUH) Ho Chi Minh CityVietnam Al-Nahrain Nanorenewable Energy Research Center Al-Nahrain UniversityBaghdadIraq Ho Chi Minh city University of Technology(HUTECH) Ho Chi Minh CityVietnam

Currently,the 65Mn steel is quenched mainly by oil *** though the lower cooling rate of oil compared to water reduces the hardness of steel post quenching,the deforming and cracking of parts are often *** the other hand,the oil media also has the disadvantage of being ammable,creating smoke that adversely affects the *** poly alkylene glycol(PAG)polymer quenchant is commonly used for quenching a variety of steels based on its advantages such as non-ammability and exible cooling rate subjected to varying concentration and stirring *** article examines the effect of PAG polymer quenching solution(with concentrations of 10%and 20%)on deformation,hardness,and microstructure of C-ring samples made of 65Mn ***,the performance of PAG polymer quenchant is also compared with those of two common quenching solutions:Water and *** cooling in water,the C-ring samples had the largest deformation and 2 times higher than the results obtained when a 10%PAG solution was *** particular,similar levels of deformation on the C-ring samples were observed in both cases of 20%PAG solution and oil as the primary quenching ***,the hardness level measured between the sampled parts quenched in the 20%PAG solution appeared to be more uniform than that obtained from the oil-quenched *** study of the microscopic structure of steel by optical microscopy combined with X-ray diffraction showed that the water hardened sample exhibited cracks and comprised of two phases,martensite and retained *** to the results of Electron Back Scattering Diffraction(EBSD)analysis and backscattering electronic image(BSE),the content of austenite residue in the sample when the sample was cooled in PAG 10 and 20%solution was 3.21%and 4.73%,respectively and smaller than the measurements obtained from oil quenching ***,the 65Mn steel is cooled in 20%PAG solution for high hardness and more evenly distributed than when it is q

关键词： Polyethylene glycol electron backscattering diffraction quenching media cooling rate backscattering electronic image

Thermodynamic Simulation on the Change in Phase for Carburizing Process

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Computers, Materials & Continua 2021年第7期68卷 1129-1145页

作者： Anh tuan Hoang Xuan Phuong nguyen Osamah Ibrahim Khalaf Thi Xuan Tran Minh quang Chau Thi Minh Hao Dong Duong Nam nguyen Ho Chi Minh city University of Technology(HUTECH) HoVietnam Ho Chi Minh city University of Transport Ho Chi Minh cityVietnam Al-Nahrain University Al-Nahrain Nanorenewable Energy Research CenterBaghdadIraq Hanoi University of Science and Technology HanoiVietnam Industrial University of Ho Chi Minh City(IUH) Ho Chi Minh cityVietnam Vietnam Maritime University HaiphongVietnam

The type of technology used to strengthen the surface structure of machine parts,typically by carbon-permeation,has made a great contribution to the mechanical engineering industry because of its outstanding advantages in corrosion resistance and enhanced mechanical and physical ***,carbon permeation is considered as an optimal method of heat treatment through the diffusion of carbon atoms into the surface of alloy *** study presented research results on the thermodynamic calculation and simulation of the carbon permeability *** Fick’s law,the paper calculated the distribution of carbon concentration in the alloy steel after it is absorbed from the surface into the internal of the *** the SYSWELD software,an analysis was performed on the carbon permeability process to determine the distribution of carbon concentrations in 20CrMo steel that was then followed by a detailed analysis of the microstructure of the sample post the carburizing *** to the calculation results,the surface carbon content was 0.9%and steadily decreased into the *** 3 hours,the depth of the absorbent layer was measured at 0.5 mm for both the cylindrical and cubic *** analyzing the phase,the distribution of martensite phases such as ferrite/pearlite and residual austenite was also determined after the carburizing process.

关键词： Carburizing process 20CrMo steel thermodynamic analysis microstructure formation carbon concentration

Hybrid model to optimize object-based land cover classification by meta-heuristic algorithm:an example for supporting urban management in Ha Noi,Viet Nam

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International Journal of Digital Earth 2019年第10期12卷 1118-1132页

作者： quang-Thanh Bui Manh Pham Van nguyen Thi Thuy Hang Quoc-Huy nguyen nguyen Xuan Linh Pham Minh Hai Tran Anh tuan Pham Van Cu Center for Applied Research in Remote sensing and GIS(CARGIS) VNU University of ScienceHa NoiViet Nam VNU University of Science Ha NoiViet Nam Vietnam Institute of Geodesy and Cartography Ha NoiViet Nam Ministry of Education and Training Ha NoiViet Nam

This study proposed a novel object-based hybrid classification model named GMNN that combines Grasshopper Optimization Algorithm(GOA)and the multiple-class Neural network(MNN)for urban pattern detection in Hanoi,*** bands of SPOT 7 image and derivable NDVI,NDWI were used to generate image segments with associated attributes by PCI Geomatics *** segments were classified into four urban surface types(namely water,impervious surface,vegetation and bare soil)by the proposed ***,three training and validation datasets of different sizes were used to verify the robustness of this *** all tests,the overall accuracies of the classification were approximately 87%,and the Area under Receiver Operating Characteristic curves for each land cover type was ***,the performance of this model was examined by comparing several statistical indicators with common benchmark *** results showed that GMNN out-performed established methods in all comparable *** results suggested that our hybrid model was successfully deployed in the study area and could be used as an alternative classification method for urban land cover *** a broader sense,classification methods will be enriched with the active and fast-growing contribution of metaheuristic algorithms.

关键词： Urban remote sensing object-based classification neural network grasshopper optimization algorithm

An electrochemical and microstructural characterization of steel-mortar admixed with corrosion inhibitors

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Science China(Technological Sciences) 2009年第1期52卷 52-66页

作者： tuan Anh nguyen Recep AVCI Corrosion and Sustainable Infrastructure Laboratory Western Transportation InstitutePO Box 174250College of Engineering Montana State University Bozeman Imaging and Chemical Analysis Laboratory Department of Physics Montana State University Bozeman

The present research brings new insights on the role of admixed corrosion inhibitors in the processes of cement hydration and rebar corrosion. The admixing of NaCl and the corrosion inhibitors in fresh mortar was found to alter the morphology and microstructure of the hardened mortar at the steel-mortar interfacial region. The admixing of the inhibitors increased the risk of carbonation of cement hydrates at the steel-mortar interfacial region, but partially displaced chloride ions. Chloride and the admixed inhibitors facilitated the formation of different cement hydrates and affected chloride binding at the steel-mortar interfacial region. The admixing of all three inhibitors was found to increase the polarization resistance of steel, indicating reduced corrosion rate of the steel over 48-day exposures to salt ponding.

关键词： corrosion inhibitor rebar corrosion steel-mortar interface FESEM EDX XPS EIS

Marketing Strategies Evaluation and Selection for Supply Chain Management Under Uncertainty

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Computers, Materials & Continua 2022年第12期73卷 6535-6546页

作者： Ngo quang Trung nguyen Van Thanh Faculty of Commerce Van Lang UniversityHo Chi Minh City70000Vietnam

Sustainable marketing,often known as green marketing,has grown in popularity over the last two *** is currently putting pressure to encourage firms to become environmentally aware in multiple aspects like human and financial utilization,advertisement,and product *** types of companies are including many environmental campaigns into their own products to take advantage of the *** many scholars have addressed the relevance of green marketing as well as theory development,this study is unique in that it examines both techniques in a fuzzy *** integrated Fuzzy Multicriteria Decision Making Model(MCDM)of the analytical hierarchy process(AHP)and a Portuguese-acronymous MCDM method(TODIM)are used to select the best marketing strategy from five alternatives:(i)Green Design,(ii)Green Positioning,(iii)Green Pricing,(v)Green Packaging,and(iv)Green *** on criteria such as the scale of the green market,price parity,and the commitment of top *** for evaluating green marketing strategies was established in the study as contributions for decisionmakers in this field under unclarified *** research also a useful guideline for ranking alternatives in others industry.

关键词： Green marketing MCDM model sustainable marketing strategy

Thrust Analysis of a Fish Robot Actuated by Piezoceramic Composite Actuators

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Journal of Bionic Engineering 2011年第2期8卷 158-164页

作者： quang Sang nguyen Hoon Cheol Park Doyoung Byun Biomimetics and bltelligent Microsystems Laboratory Department of Advanced Technology Fusion Konkuk University Seoul 143-701 South Korea Department of Advanced Technology Fusion Konkuk University Seoul 143-701 South Korea Department of Aerospace Engineering Konkuk University Seoul 143-701 South Korea

In this work, a three-dimensional （3D） Computational Fluid Dynamics （CFD） model was built to simulate the tail fin motion of a fish robot actuated by a piezoceramic composite actuator, and to determine the maximum thrust tail-beat frequency. A simulation of the tail fin at a tail-beat frequency was performed to confirm measured thrust data from a previous study. The computed and measured thrusts were in good agreement. A series of thrust simulations were conducted for various tail-beat frequencies to confirm the maximum thrust frequency that was obtained from thrust measurements in the previous study. The largest thrust was calculated at a tail-beat frequency of 3.7 Hz and vortices around the tail were fully separated. The calculated maximum thrust tail-beat frequency was in good agreement with the measured frequency. Flow characteristics during tail fin motion were examined to explain why the largest thrust occurred at this particular tail-beat frequency.

关键词： fish robot CFD LIPCA thrust measurement thrust analysis composite actuator vortex shedding

An Efficient Differential Evolution for Truss Sizing Optimization Using AdaBoost Classifier

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Computer Modeling in Engineering & Sciences 2023年第1期134卷 429-458页

作者： Tran-Hieu nguyen Anh-tuan Vu Hanoi University of Civil Engineering Hanoi100000Vietnam

Design constraints verification is the most computationally expensive task in evolutionary structural optimization due to a large number of structural analyses thatmust be *** a surrogatemodel to approximate the behavior of structures instead of the exact structural analyses is a possible solution to tackle this ***,most existing surrogate models have been designed based on regression *** paper proposes a novel method,called CaDE,which adopts a machine learning classification technique for enhancing the performance of the Differential Evolution(DE)*** proposed method is separated into two *** the first optimization stage,the original DE is implemented as usual,but all individuals produced in this phase are stored as inputs of the training *** on design constraints verification,these individuals are labeled as“safe”or“unsafe”and their labels are saved as outputs of the training *** collecting enough data,an AdaBoost model is trained to evaluate the safety state of *** model is then used in the second stage to preliminarily assess new individuals,and unpromising ones are rejected without checking design *** method reduces unnecessary structural analyses,thereby shortens the optimization *** benchmark truss sizing optimization problems are solved using the proposed method to demonstrate its *** obtained results show that the CaDE finds good optimal designs with less structural analyses in comparison with the original DE and four other DE *** reduction rate of five examples ranges from 18 to over 50%.Moreover,the proposed method is applied to a real-size transmission tower design problem to exhibit its applicability in practice.

关键词： Structural optimization machine learning surrogate model differential evolution AdaBoost classifier