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Journal of Civil Engineering and Architecture 2012年第10期6卷 1392-1398页

作者： tran tuan anh School of Architecture and Design RMIT University Melbourne 3001 Australia Faculty of Architecture College of Sciences Hue University Hue 8454 Vietnam

Disaster mitigation for marginal communities has become one of the most significant development goals of the 21st century. Vietnam has been reported one of the five most vulnerable nations in the world to climate change and so serves as a useful case study in developing appropriate housing solutions after disasters. In addition, some local communities in remote mountainous areas of Vietnam still keep strong vernacular traditions in their housing, especially the typical timber house-on-stilt, which need intense consideration before employing any new techniques of disaster mitigation on them. Perceptions on how to develop a sustainable housing solution for such communities, therefore, is still controversial with very few useful options developed to date. The paper investigates the existing unsafe conditions of traditional houses of a local community in the central highland of Vietnam, exposed to natural disasters, together with an identification of several traditional features of this housing that would be needed to preserve in future construction. Some important gaps of these traditional houses in terms of disaster risk reduction are then displayed to show opportunities where new construction techniques have a high possibility to perform against extreme climate events.

关键词： Disaster vernacular housing housing design housing reconstruction

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

Development of 24 and 59 keV Filtered Neutron Beams for Neutron Capture Experiments at Dalat Research Reactor

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World Journal of Nuclear Science and Technology 2014年第2期4卷 59-64页

作者： Pham Ngoc Son Vuong Huu Tan Phu Chi Hoa tran tuan anh Nuclear Research Institute Dalat Vietnam The University of Dalat Dalat Vietnam Vietnam Agency for Radiation and Nuclear Safety Hanoi Vietnam

External filtered neutron beams have been developed at the horizontal radial channels No. 4 of Dalat research reactor. In the material composition of the neutron filters, the primary material components of Iron, Aluminum, Nickel and Vanadium are used to obtain the mono-energetic neutron beams of 24 and 59 keV, with low level of Gamma and slow neutron background. A computer code and Monte-Carlo simulation technique were applied to optimize the filter configurations and to deduce the neutron energy distributions in the filtered beams. A hydrogen-filled proton recoil detector and the activation method with Gold foils were used to measure the neutron energy spectrum and flux of each beam at sample position. The results of experimental neutron fluxes are 6.1 × 105 and 5.3 × 105 n/cm2/s for 24 and 59 keV beams, respectively.

关键词： Research Reactor Filtered Neutron 24 keV 59 keV

Effect of Temperature Dependence on Electrical Characterization of <i>p-n</i>GaN Diode Fabricated by RF Magnetron Sputtering

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Materials Sciences and Applications 2015年第9期6卷 809-817页

作者： Thi tran anh tuan Dong-Hau Kuo Cheng-Che Li Guan-Zhang Li Department of Materials Science and Engineering National Taiwan University of Science and Technology Taiwan School of Basic Sciences Tra Vinh University Tra Vinh Vietnam

The p-n junction GaN diodes were all fabricated by sputtering technique with cermet targets for p- and n-type GaN and metal targets for electrodes. The interface of these p-n junction GaN diodes examined by high-resolution transition electron microscopy was clear and distinguishable. Lattice images identified the complete dissolution of Mg into the Ga site. At the room temperature, the diode had the turn-on voltage of 2.2 V, the leakage current of 2.2 × 10–7 A, the breakdown voltage of –6 V, the barrier height of 0.56 eV, ideality factor of 5.0 by I (current)-V (voltage) test and 5.2 derived from the Cheungs’ method, and series resistance of 560 Ω. These electrical properties were investigated at different testing temperatures from room temperature to 200°C. The temperature dependence in the I-V characteristics of the p-n diodes can be successfully explained on the basis of thermionic-emission mode.

关键词： p-n GaN Diode I-V Measurement Barrier Height Leakage Current Cheungs’ Method

EP Aquarii:A New Picture of the Circumstellar Envelope

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Research in Astronomy and Astrophysics 2024年第3期24卷 83-105页

作者： Pham T.Nhung Do T.Hoai Pierre Darriulat Pham tuan-anh Pham N.Diep Nguyen B.Ngoc tran T.Thai Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18Hoang Quoc VietNghia DoCau GiayHa Noivietnam

New analyses of earlier ALMA observations of oxygen-rich AGB star EP Aquarii are presented,which complete a previously published analysis and offer a different interpretation of the morpho-kinematics of the circumstellar *** birth of the equatorial density enhancement(EDE)is shown to occur very close to the star where evidence for rotation has been *** to the star and where outflows have been observed:their interaction with the gas of the nascent EDE is seen to play an important role in the development of the wind and the evolution of its radial velocity from 8 to 10 km s^(-1) on the polar symmetry axis to~2 km s^(-1) at the *** implies complex morpho-kinematics:making reliable interpretations with reasonable confidence is *** particular,it questions an earlier interpretation implying the presence of a white dwarf companion orbiting the star at an angular distance of -0″4 from its *** proposes instead an interpretation in terms of a standard mass ejection associated with a shock wave leaving a void of emission in its *** Doppler velocity wings are seen to consist of two components,the upper velocity end of the global wind,reaching above±12 km s^(-1),and an effective line broadening,confined within 200 mas from the center of the star,reaching above±20 km s^(-1) and interpreted as caused by the pattern of shock waves resulting from the interaction between stellar pulsation and convective cell partition.

关键词： stars AGB and post-AGB-(stars) circumstellar matter-radio lines stars

Characteristics of Filtered Neutron Beam Energy Spectra at Dalat Reactor

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World Journal of Nuclear Science and Technology 2014年第2期4卷 96-102页

作者： tran tuan anh Pham Ngoc Son Vuong Huu Tan Pham Dinh Khang Phu Chi Hoa Nuclear Research Institute Dalat Vietnam The University of Dalat Dalat Vietnam Vietnam Agency for Radiation and Nuclear Safety Hanoi Vietnam

Filtered neutron technique was applied for producing quasi-monoenergetic neutron beams of 24 keV, 54 keV, 133 keV and 148 keV at the horizontal neutron channel No. 4 of the Dalat Nuclear Research Reactor. The study on physical characteristics of these beam lines has been carried out for efficient applications in neutron capture experiments. The filtered neutron spectrum of each beam has been simulated by Monte-Carlo method and experimentally measured by a gas-filled protonrecoil spectrometer. The neutron fluxes of these filtered beams were measured by the activation technique with standard foils of 197Au, using a high efficient HPGe digital gamma-ray spectrometer.

关键词： Neutron Filter Proton-Recoil

transient response of doubly-curved bio-inspired composite shells resting on viscoelastic foundation subject to blast load using improved first-order shear theory and isogeometric approach

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Defence Technology（防务技术） 2024年第8期38卷 171-193页

作者： Thuy tran Thi Thu Tu Nguyen anh Hue Nguyen Thi Hong Nguyen Thi School of Mechanical and Automotive Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Technical Fundamental University of Transport TechnologyHanoiViet Nam Faculty of Mechanical Engineering Thuyloi University175 Tay SonDong DaHanoiViet Nam

Investigating natural-inspired applications is a perennially appealing subject for scientists. The current increase in the speed of natural-origin structure growth may be linked to their superior mechanical properties and environmental resilience. Biological composite structures with helicoidal schemes and designs have remarkable capacities to absorb impact energy and withstand damage. However, there is a dearth of extensive study on the influence of fiber redirection and reorientation inside the matrix of a helicoid structure on its mechanical performance and reactivity. The present study aimed to explore the static and transient responses of a bio-inspired helicoid laminated composite(B-iHLC) shell under the influence of an explosive load using an isomorphic method. The structural integrity of the shell is maintained by a viscoelastic basis known as the Pasternak foundation, which encompasses two coefficients of stiffness and one coefficient of damping. The equilibrium equations governing shell dynamics are obtained by using Hamilton's principle and including the modified first-order shear theory,therefore obviating the need to employ a shear correction factor. The paper's model and approach are validated by doing numerical comparisons with respected publications. The findings of this study may be used in the construction of military and civilian infrastructure in situations when the structure is subjected to severe stresses that might potentially result in catastrophic collapse. The findings of this paper serve as the foundation for several other issues, including geometric optimization and the dynamic response of similar mechanical structures.

关键词： Blast load Modified first-order shear theory Biological composite structures

Material and Device Developments of p/n Ⅲ-Nitrde Thin Films made by Low-Temperature Sputtering

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Material and Device Developments of p/n Ⅲ-Nitrde Thin Films...

Generating highly active oxide-phosphide heterostructure through interfacial engineering to break the energy scaling relation toward urea-assisted natural seawater electrolysis

第二届海峡两岸功能材料科技与产业峰会（2015）

作者： Dong-Hau Kuo Thi tran anh tuan Cheng-Che Li Wei-Chun Yen Department of Materials Science and Engineering "National Taiwan University of Science and Technology"

GaN and In GaN layers have been deposited by metal-organic vapor deposition(MOCVD)and molecular beam *** MOCVD,In GaN films grown at 550-900 oC use trimethylindium(TMIn),trimethylgallium(TMGa),and NH as reaction precursors and N as carrier *** high capital cost and process temperature and the utilization of dangerous precursors are the major concerns of MOCVD process.p-Ga N films grown at 1000

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Journal of Energy Chemistry 2024年第10期97卷 687-699,I0014页

作者： Ngoc Quang tran Nam Hoang Vu Jianmin Yu Khanh Vy Pham Nguyen Thuy Tien Nguyen tran Thuy-Kieu Truong Lishan Peng Thi anh Le Yoshiyuki Kawazoe Center for Innovative Materials and Architectures Ho Chi Minh City 700000Vietnam Vietnam National University Ho Chi Minh City 700000Vietnam Faculty of Materials Science and Technology University of ScienceHo Chi Minh City 700000Vietnam Department of Mechanical Engineering Hanbat National University(HBNU)Daejeon 34158Republic of Korea Key Laboratory of Rare Earths Ganjiang Innovation AcademyChinese Academy of SciencesGanzhou 341119JiangxiChina School of Chemical Engineering-Hanoi University of Science and Technology Hanoi 10000Vietnam New Industry Creation Hatchery Center Tohoku UniversitySendai 980-8579Japan

Urea-assisted natural seawater electrolysis is an emerging technology that is effective for grid-scale carbon-neutral hydrogen mass production yet *** scaling relations is an effective strategy to break through the bottleneck of natural seawater ***,by DFT calculation,we demonstrated that the interface boundaries between Ni_(2)P and MoO_(2) play an essential role in the selfrelaxation of the Ni-O interfacial bond,effectively modulating a coordination number of intermediates to control independently their adsorption-free energy,thus circumventing the adsorption-energy scaling *** this conceptual model,a well-defined 3D F-doped Ni_(2)P-MoO_(2) heterostructure microrod array was rationally designed via an interfacial engineering strategy toward urea-assisted natural seawater *** a result,the F-Ni_(2)P-MoO_(2) exhibits eminently active and durable bifunctional catalysts for both HER and OER in acid,alkaline,and alkaline sea water-based *** in-situ analysis,we found that a thin amorphous layer of NiOOH,which is evolved from the Ni_(2)P during anodic reaction,is real catalytic active sites for the OER and UOR ***,such electrode-assembled urea-assisted natural seawater electrolyzer requires low voltages of 1.29 and 1.75 V to drive 10 and600 mA cm^(-2)and demonstrates superior durability by operating continuously for 100 h at 100 mA cm^(-2),beyond commercial Pt/C||RuO_(2) and most previous reports.

关键词： Interfacial engineering Break scaling relationships Doping Natural seawater splitting Urea electrolysis

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