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Journal of Materials Science & Technology 2015年第5期31卷 479-483页

作者： Nguyen Van Chuc Cao Thi Thanh Nguyen Van tu Vuong T.Q phuong Pham viet Thang Ngo Thi Thanh Tam Institute of Materials Science Vietnam Academy of Science and Technology Hanoi University of Science Vietnam National University

In this study,graphene-carbon nanotube（CNT） hybrid films were directly synthesized on polycrystalline copper（Cu） substrates by thermal chemical vapor deposition（CVD） *** films were synthesized on Cu substrate at 1000 ℃ in mixture of gases:argon（Ar）,hydrogen（H2）,and methane（CH4）.Then,carbon nanotubes（CNTs） were grown uniformly on the surface of graphene/Cu films at 750 ℃ in mixture of Ar,*** acetylene（C2H2） *** salt FeCl3solution deposited onto the surface of graphene/Cu substrate by spin coating method was used as precursor for the growth of the *** density and quality of the CNTs on the surface of graphene/Cu films can be controlled by varying the concentration of FeCl3salt catalyst.

关键词： Graphene Carbon nanotube(CNT) Hybrid films Copper

Concentrations of Heavy Metals in Muscle with Relation to the Growth of Two Marine Fish Species

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生态毒理学报 2015年第3期10卷 304-310页

作者： Le Quang Dung Nguyen viet Linh Nguyen Xuan Thanh Nguyen Duc Cu Vu Van tu3 Takaomi Arai Institute of Marine Environment and Resources Vietnam Academic of Science and Technology Haiphong Vietnam Institute of Oceanography and Environment Universiti Malaysia Terengganu Kuala Terengganu Malaysia Institute of Environmental Technology Vietnam Academic of Science and Technology Hanoi Vietnam

Heavy metal concentrations in muscle and their relation to thegrowth of two marine fish species,including tonguefish( Cynoglossus arel) and mullet( Mugil cephalus),were studied. The samples were collected in Bach Dang estuary andconcentrations of heavy metals( As,Cd,Co,Mn,Cu,Zn,Pb,and V) in muscle of the fisheswere determined. The result showed that the accumulated trend of heavy metal is different between fish species. The concentration of As,Zn,Mn,V,Cu,Pb,Co and Cd in tonguefish were 73. 7 ± 30. 6,22. 82 ± 4.87,3. 44 ± 2. 13,1. 61 ± 0. 15,0. 71 ± 0. 13,0. 45 ± 0. 24,0. 03 ± 0. 02 and 0. 02 ± 0. 02 mg·g-1,respectively. Meanwhile the concentration of Zn,As,V,Mn,Cu,Pb,Co and Cd in mullet were 83. 41 ±19. 68,9. 78 ± 1. 92,1. 36 ± 0. 54,1. 29 ± 0. 51,0. 65 ± 0. 12,0. 42 ± 0. 20,0. 06 ± 0. 03 and0. 03 ± 0. 01mg·g-1,respectively. Comparison of metal levels among thesespecies indicated that the concentrations of As and Mn in tonguefish were significantly higher than those in mullet,whereas Zn levels in mullet were found to be higher than that in tonguefish. There is no significant differences of Cd,Co,Cu,Pb and V levels in muscle between two species. Significant inversed relationshipsbetween concentration levels of metals and lengths of tonguefish were found for Mn,Cu and Zn,butnot for As,Cd,Pb,and V. There were no significant relationships between the heavy metal concentrations and the length of mullet. In general,decreasesof the heavy metal concentrations corresponded to the increases of fish body lengths,particularly for As,Co,Cu,Mn and V and the exception for Cd. Terefore reduced risks were associated with consuming biggermullet fish,and increased risks of As and Cd were associated with consuming bigger tonguefish in Bach Dang river mouth.

关键词： heavy metals concentration levels marine fish health risk vietnam

Isogeometric analysis for free vibration of bidirectional functionally graded plates in the fluid medium

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Defence Technology（防务技术） 2022年第8期18卷 1311-1329页

作者： Quoc-Hoa Pham phu-Cuong Nguyen Van Ke Tran Trung Nguyen-Thoi Faculty of Civil Engineering Ho Chi Minh City Open UniversityHo Chi Minh CityViet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiViet Nam Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh CityViet Nam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh CityViet Nam

This paper for first time proposes an isogeometric analysis (IGA) for free vibration response of bi-directional functionally graded (BDFG) rectangular plates in the fluid medium. Material properties of the BDFG plate change in both the thickness and length directions via power-law distributions and Mori-Tanaka model. The governing equation of motion of BDFG plate in the fluid-plate system is formulated basing on Hamilton's principle and the refined quasi three-dimensional (3D) plate theory with improved function f(z). The fluid velocity potential is derived from the boundary conditions of the fluid-plate system and is used to determine the added mass. The discrete system of equations is derived from the Galerkin weak form and numerically analyzed by IGA. The accuracy and reliability of the proposed solutions are verified by comparing the obtained results with those published in the literature. Moreover, the effects of the various parameters such as the interaction boundary condition, geometric parameter, submerged depth of plate, fluid density, fluid level, and the material volume control coefficients on the free vibration behavior of BDFG plate in the fluid medium are investigated in detail. Some major findings regarding the numerical results are withdrawn in conclusions.

关键词： Contact plate-fluid Refined quasi 3D plate theory Mori-Tanaka model Isogeometric analysis Bidirectional functionally graded plate

Forest Change and Its Effect on Biomass in Yok Don National Park in Central Highlands of vietnam Using Ground Data and Geospatial Techniques

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Advances in Remote Sensing 2015年第2期4卷 108-118页

作者： Nguyen viet Luong Ryutaro Tateishi Nguyen Thanh Hoan To Trong tu Space Technology Institute Vietnam Academy of Science and Technology Hanoi Vietnam Center for Environmental Remote Sensing Chiba University Chiba Japan Institute of Geography Vietnam Academy of Science and Technology Hanoi Vietnam

This paper assesses the changes in forest cover in Yok Don National Park of vietnam between 2004 and 2010, and the implications of such changes on the biomass stocks of this national park. Remote sensing and GIS tools along with the ground truth data collected from the field were employed for classifying the forest types of the study area from SPOT HRV satellite imagery for years 2004 and 2010. The total area considered in this study is 115.5 thousand ha. Five different categories of forests were identified. The results demonstrated that between 2004 and 2010, the Evergreen broad leaved rich quality forest decreased by 11.2 thousand ha (3.5 Mega tons of biomass) and the Dry open dipterocarps medium quality forest decreased by 15.3 thousand ha (2.5 Mega tons of biomass). In that time period, the Evergreen broad leaved medium quality forest increased by 3.2 thousand ha (0.8 Mega tons of biomass), the Evergreen broad leaved poor quality forest increased by 2.5 thousand ha (0.24 Mega tons of biomass), and the Dry open dipterocarps poor quality forest increased by 3.2 thousand ha (0.69 Mega tons of biomass). Total biomass of the study area decreased by 4.3 Mega tons.

关键词： Satellite Data SPOT HRV Land Cover Change Tropical Forest Biomass

Dynamic analysis of bio-inspired helicoid laminated composite plates resting on Pasternak foundation excited by explosive loading

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Defence Technology（防务技术） 2023年第12期30卷 126-140页

作者： Ngoc-tu Do Quoc-Hoa Pham Faculty of Mechanical Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Engineering and Technology Nguyen Tat Thanh UniversityHo Chi Minh CityViet Nam

This paper uses isogeometric analysis(IGA)based on higher-order shear deformation theory(HSDT)to study the dynamic response of bio-inspired helicoid laminated composite(B-iHLC)plates resting on Pasternak foundation(PF)excited by explosive *** takes advantage of non-uniform rational Bspline(NURBS)basic functions to exactly represent the structure geometry models and the attainment of higher-order approximation *** method also ensures a C1 continuous function in the analysis of transverse shear deformation via ***,IGA eliminates the requirement for correction factors and delivers accurate *** foundation with two stiffness parameters:springer stiffness(k_(1))and shear stiffness(k_(2)).The derivation of the governing equations is based on Hamilton's *** proposed method is validated through numerical examples.A comprehensive analysis of the impact of geometrical parameters,material properties,boundary conditions(BCs),and foundation stiffness on dynamic response of B-i HLC plates is carried out.

关键词： Isogeometric analysis Pasternak foundation Dynamic response Laminated composite

Combining SnO_(2-x)and g-C_(3)N_(4)nanosheets toward S-scheme heterojunction for high selectivity into green products of NO degradation reaction under visible light

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Journal of Materiomics 2022年第1期8卷 1-8页

作者： Pham Van viet Thanh-Dat Nguyen Dai-Phat Bui Cao Minh Thi Faculty of Materials Science and Technology University of ScienceVNU-HCM227 Nguyen Van Cu StreetDistrict 5Ho Chi Minh City700000Viet Nam vietnam National University-Ho Chi Minh City Thu Duc DistrictHo Chi Minh City700000Viet Nam Ho Chi Minh City University of Technology(HUTECH) 475A Dien Bien Phu StreetBinh Thanh DistrictHo Chi Minh City700000Viet Nam

NOx emissions cause many negative impacts on the living *** photocatalysis of semiconductors is superior for nitric oxide(NO)degradation due to their low redox *** this report,we combine SnO_(2-x)/g-C_(3)N_(4)heterojunction photocatalyst toward the high selectivity into green products under visible light *** show that SnO_(2-x)/g-C_(3)N_(4)heterojunction degraded 40.8%of NO,which is 1.6 times higher than that of g-C_(3)N_(4).In addition,the selectivity coefficient of SnO_(2-x)/g-C_(3)N_(4)is higher 3 times than both pure SnO_(2-x)and g-C_(3)N_(4).Furthermore,SnO_(2-x)/g-C_(3)N_(4)expresses a superior stability for NO photocatalytic-degradation after five *** scavenger trapping test results,and electron spin resonance(ESR)analysis also provide more understanding of the charge transfer mechanism of ***_(2-x)/g-C_(3)N_(4)heterojunction shows a high removal efficiency of NO gas,making it an up-and-coming environmental treatment candidate.

关键词： G-C_(3)N_(4) NO removal Oxygen vacancies Photocatalysis S-scheme

Comparative study on water-soluble inorganic ions in PM2.5 from two distinct climate regions and air quality

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Journal of Environmental Sciences 2020年第2期32卷 349-360页

作者： Duong Huu Huy Le tu Thanh To Thi Hien Norimichi Takenaka Faculty of Food Science and Technology Ho Chi Minh City University of Food Industry140 Le Trong Tan StreetTan Phu DistrictHo Chi Minh CityViet Nam Faculty of Environment University of ScienceVietnam National University–Ho Chi Minh City227 Nguyen Van Cu StreetDistrict 5Ho Chi Minh CityViet Nam Graduate School of Humanities and Sustainable System Sciences Osaka Prefecture University1-1 Gakuen-choNaka-kuSakai-shiOsaka 599-8531Japan

Recently, air quality has significantly improved in developed country, but that issue is of concern in emerging megacity in developing *** this study, aerosols and their precursor gas were collected by NILU filter pack at two distinct urban sites during the winter and summer in Osaka, Japan and dry and rainy seasons in Ho Chi Minh City(HCMC),*** aims are to investigate the contribution of water-soluble inorganic ions(WSIIs) to PM2.5, thermodynamic characterization and possible formation pathway of secondary inorganic aerosol(SIA).The PM2.5 concentration in Osaka(15.8 μg/m^3) is lower than that in HCMC(23.0 μg/m^3), but the concentration of WSIIs in Osaka(9.0 μg/m^3) is two times higher than that in HCMC(4.1 μg/m^3).Moreover, SIA including NH4^+, NO3^-and SO4^2-are major components in WSIIs accounting for 90% and 76%(in molar) in Osaka and HCMC,*** models were used to understand the thermodynamic characterization of urban ***, statistical analysis results indicate that very good agreement(R2> 0.8) was found for all species, except for nitrate aerosol in *** found that when the crustal species present at high amount, those compositions should be included in model calculation(*** the HCMC situation).Finally, we analyzed the characteristics of NH4^+– NO3^-– SO4^2-system.A possible pathway to produce fine nitrate aerosol in Osaka is via the homogeneous reaction between NH3 and HNO3, while nonvolatile nitrate aerosols can be formed by the heterogeneous reactions in HCMC.

关键词： Water-soluble inorganic ions Thermodynamic model PM2.5

Estimation of Tropical Forest Structural Characteristics Using ALOS-2 SAR Data

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Advances in Remote Sensing 2016年第2期5卷 131-144页

作者： Luong viet Nguyen Ryutaro Tateishi Hoan Thanh Nguyen Ram C. Sharma tu Trong To Son Mai Le Center for Environmental Remote Sensing Chiba University Chiba Japan Space Technology Institute Vietnam Academy of Science and Technology Hanoi Vietnam Institute of Geography Vietnam Academy of Science and Technology Hanoi Vietnam

The potential of ALOS-2 SAR data for the estimation of tropical forest structural characteristics was assessed in vietnam by collecting forest inventory data. The effect of polarization and seasonality of the SAR data on the estimation of forest biomass was analyzed. The combination of HH, HV, and HH/HV polarizations using multiple linear regression did not improve the estimation of biomass compared to using the HV channel independently, as the HH and HH/HV variables were not statistically significant. The dry season HV backscattering intensity was highly sensitive to the biomass compared to the rainy season backscattering intensity. The SAR data acquired in the rainy season with humid and wet canopies was not very sensitive to the biomass. The strong dependence of the biomass estimates with the season of SAR data acquisition confirmed that the choice of right season SAR data is very important for improving the satellite based estimates of the biomass. The validation results showed that the dry season HV polarization could explain 54% variation of the biomass.

关键词： Forest Structure Forest Biomass SAR ALOS-2 Backscattering Intensity Sensitivity Analysis

NOTES SUR LE PHOTOSTADE DE QUELQUES VARIETES DE RIZ AU viet-NAM DEMOCRATIQUE

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植物生理学报 1959年第3期 11-22页

作者： BUI HUY DAP NGHIEM phu CHUAN Directeur de l'Institut d'Agriculture et de Sylviculture de Hanoi Chef du Laboratoire de Physiologie végétale

En raison du climat tropical du pays,au viet-Nam on peut faire plusieurs campagnes de riz paran,dont les principales sont les suivantes pour la région du Nord:—Campagne du cinquième mois,avec semis en Novembre,Déc... 详细信息

关键词： der FL 植物生理学 NOTES SUR LE PHOTOSTADE DE QUELQUES VARIETES DE RIZ AU viet-NAM DEMOCRATIQUE IV DE NAM

Seasonal Effects of Backscattering Intensity of ALOS-2 PALSAR-2 (L-Band) on Retrieval Forest Biomass in the Tropics

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Journal of Geoscience and Environment Protection 2020年第11期8卷 26-40页

作者： Luong viet Nguyen Hieu Van Nguyen Lap Quoc Kieu tu Trong To Thanh Kim Thi Phan tuan Anh Pham Chi Kim Tran Space Technology Institute Vietnam Academy of Science and Technology Hanoi Vietnam Thai Nguyen University of Sciences Thai Nguyen City Vietnam

This research has used the L-band radar from ALOS-2 PALSAR-2 and field work data for evaluation of seasonal effects of backscattering intensity on retrieval forest biomass in the tropics. The effects of seasonality and HH, and HV polarizations of the SAR data on the biomass were analyzed. The dry season HV polarization could explain 61% of the biomass in this study region. The dry season HV backscattering intensity was highly sensitive to the biomass compared to the rainy season backscattering intensity. The SAR data acquired in the rainy season with humid and wet canopies were not very sensitive to the in situ biomass. Strong dependence of the biomass estimates with season of SAR data acquisition confirmed that the choice of right season SAR data is very important for improving the satellite based estimates of the biomass. This research expects that the results obtained in this research will contribute to monitoring of the quantity and quality of forest biomass in vietnam and other tropical countries.

关键词： L-Band SAR ALOS-2 PALSAR-2 Backscattering Intensity Tropical Forest Biomass vietnam