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Ecoregional variations of aboveground biomass and stand structure in evergreen broadleaved forests

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Journal of Forestry Research 2020年第5期31卷 1713-1722页

作者： tran Van Do Mamoru Yamamoto Osamu Kozan Vo Dai Hai phung Dinh Trung nguyen Toan Thang Lai Thanh Hai Vu Thanh Nam Trieu Thai Hung Hoang Van Thang tran Duc Manh Cao Chi Khiem Vu Tien Lam nguyen Quang Hung tran Hoang Quy Pham Quang Tuyen Trinh ngoc Bon nguyen Thi Thu phuong Ninh Viet Khuong nguyen Van Tuan Dang Thi Hai Ha tran Hai Long Dang Van Thuyet Dang Thinh Trieu nguyen Van Thinh tran Anh Hai Duong Quang Trung nguyen Van Bich Dinh Hai Dang Pham Tien Dung nguyen Huy Hoang Le Thi Hanh Phan Minh Quang nguyen Thi Thuy Huong Hoang Thanh Son nguyen Thanh Son nguyen Thi Van Anh nguyen Thi Hoai Anh Pham Dinh Sam Hoang Thi Nhung Hoang Van Thanh nguyen Huu Thinh tran Hong Van Ho Trung Luong Bui Kieu Hung Research Institute for Sustainable Humanosphere Kyoto UniversityUjiKyotoJapan Silviculture Research Institute Vietnamese Academy of Forest SciencesNorth Tu LiemHanoiVietnam Center for Southeast Asian Studies Kyoto UniversityKyotoJapan Vietnamese Academy of Forest Sciences North Tu LiemHanoiVietnam Vietnam Administration of Forestry No.2 Ngoc HaBa DinhHanoiVietnam

Biotic and abiotic factors control aboveground biomass(AGB)and the structure of forest *** study analyses the variation of AGB and stand structure of evergreen broadleaved forests among six ecoregions of Vietnam.A data set of 1731-ha plots from 52 locations in undisturbed old-growth forests was *** results indicate that basal area and AGB are closely correlated with annual precipitation,but not with annual temperature,evaporation or hours of *** area and AGB are positively correlated with trees>30 cm *** areas surveyed(52.6%)in these old-growth forests had AGB of 100–200 Mg ha^-1;5.2%had AGB of 400–500 Mg ha^-1,and 0.6%had AGB of>800 Mg ha^-*** percent of the areas surveyed had stand densities of 300–600 ***^-1,and 64%had basal areas of 20–40 m^2 ha^-*** is an important factor influencing the AGB of old-growth,evergreen broadleaved forests in *** causing the loss of large-diameter trees(e.g.,>100 cm DBH)affects AGB but may not seriously affect stand density.

关键词： Aboveground biomass Carbon storage Climatic variables Ecoregion Edaphic variables Oldgrowth forest

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

Induction of Anthracnose Disease Resistance on Chili Fruit by Treatment of Oligochitosan—Nanosilica Hybrid Material

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Agricultural Sciences 2017年第10期8卷 1105-1113页

作者： Pham Dinh Dzung Le Thanh Hung Le Si ngoc Hoang Dac Hiet Bui Van Le nguyen Tien Thang Dang Van phu nguyen ngoc Duy nguyen Quoc Hien Research and Development Center for Hi-Tech Agriculture Ho Chi Minh City Vietnam Graduate University of Science and Technology Vietnam Academy of Science and Technology Hanoi Vietnam University of Science Vietnam National University Ho Chi Minh City Vietnam Research and Development Center for Radiation Technology Vietnam Atomic Energy Institute Ho Chi Minh City Vietnam

Oligochitosan (OC) with molecular weight Mw of 5000 g/mol was prepared by gamma Co-60 ray irradiation of chitosan solution. Nanosilica (nSiO2) with the size of 10 - 30 nm was synthesized by calcination of acid treated rice husk. The mixture of 1% OC - 1% nSiO2 was prepared by dispersion of nSiO2 in OC solution. The morphology of nSiO2 in the mixture of OC-nSiO2 was measured from images of transmission electron microscopy (TEM). The effect of foliar application of the mixture of OC-nSiO2 on the induction of resistance against anthracnose disease caused by Colletotrichum gloeosporioides fungus on chili fruits was investigated. Results indicated that foliar application of OC-nSiO2 with the concentration of 60 mg/l - 60 mg/l was found to be as the optimal treatment that reduced the disease severity on chili fruits to 22.2% compared with 90.0% of the control. Thus, OC-nSiO2 hybrid material could be considered as an effective biotic elicitor to prevent anthracnose disease infection for chili fruits. Furthermore, the prepared OC-nSiO2 hybrid material can also be used as an environmentally friendly agrochemical product for sustainable development of agriculture.

关键词： Oligochitosan Nanosilica Chili Fruit Colletotrichum gloeosporioides Anthracnose

Preparation and Characterization of Silver Doped ZnO Nanostructures

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Open Journal of Synthesis Theory and Applications 2012年第2期1卷 18-22页

作者： nguyen Van Nghia tran Nam Trung nguyen ngoc Khoa Truong Doan Minh Thuy Department of Physics Quy Nhon University Quy Nhon Vietnam

ZnO was prepared by hydrothermal method. The result of scanning electron microscopy showed that the materials had nano rod structures. Ag-doped ZnO was prepared by UV-photoreduction. Crystalline phases and optical absorption of the prepared Ag-doped ZnO samples were determined by X-ray diffraction, Raman spectrum, UV-visible, and UV- photoreduction spectrophotometer. X-ray analyses revealed that Ag was doped ZnO crystallizes in hexagonal wurtzite structure. The incorporation of Ag+ in the site of Zn2+ provoked an increase in the size of nanocrystals as compared to pure ZnO. The photocatalytic and photoluminescence properties of materials were considered.

关键词： Nanostructures Photocatalysis Hydrothermal ZnO Silver Doping

Green Synthesis of Carvenone by Montmorillonite-Catalyzed Isomerization of 1,2-Limonene Oxide

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International Journal of Organic Chemistry 2013年第3期3卷 206-209页

作者： Thao-tran Thi nguyen Duy-Khiem nguyen Chau Fritz Duus Thach ngoc Le Department of Organic Chemistry Hochiminh University of Science Hochiminh City Vietnam Department of Science Systems and Models Roskilde University Roskilde Denmark

Montmorillonite was considered as a good heterogeneous catalyst for the isomerization of 1,2-limonene oxide into car-venone under solvent-free condition. Both conventional heating and green activations were tested in ... 详细信息

关键词： Carvenone Isomerization Green Chemistry Montmorillonite Solvent-Free Synthesis

Influence of Chitosan Binder on the Adhesion of Silver Nanoparticles on Cotton Fabric and Evaluation of Antibacterial Activity

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Advances in Nanoparticles 2015年第4期4卷 98-106页

作者： nguyen Quoc Hien Dang Van phu nguyen ngoc Duy Le Anh Quoc nguyen T. Kim Lan Hoang T. Dong Quy Huynh T. Hong Van Phan Ha Nu Diem tran Thai Hoa Research and Development Center for Radiation Technology Vietnam Atomic Energy Institute Ho Chi Minh City Vietnam University of Science Vietnam National University in Ho Chi Minh City Ho Chi Minh City Vietnam College of Science Hue University Hue City Vietnam

Colloidal silver nanoparticles (AgNPs) with particle size less than 10 nm and concentration of 2 mM/L (~200 mg/L) were synthesized by gamma Co-60 ray irradiation of Ag+/chitosan solutions with different chitosan concentration of 0.5%, 1% and 2% (w/v). Incorporation of AgNPs onto cotton fabric was carried out by padding method with 100% wet pick-up. The content of AgNPs deposited on cotton fabric and released from cotton fabric after repeated washing was determined by inductively couple plasma-atomic emission spectroscopy (ICP-AES). The results indicated that cotton/AgNPs fabric made from padding into AgNPs solution with 0.5% - 1% chitosan was the best one of AgNPs adhesion ability on cotton fabric. Results on antibacterial activity against S. aureus showed that cotton/AgNPs fabric with AgNPs content more than 100 mg/kg exhibited highly antibacterial activity (η > 98%). The mechanical property (tensile strength and elongation) of cotton/AgNPs fabrics was almost unchanged in comparison with untreated cotton fabric. Thus, the resultant cotton/AgNPs fabric with highly antibacterial activity can be potentially used as bed drapes and/or patient uniforms in hospitals, etc.

关键词： Gamma Co-60 Ray Silver Nanoparticles Chitosan Cotton Fabric Antibacterial

Assessment of Growth and Productivity on Four Black Pepper Varieties (<i>Piper nigrum</i>L.) in Three Target Provinces of Vietnam

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Engineering（科研） 2021年第12期13卷 647-655页

作者： Duong Thi Oanh nguyen Van Long nguyen Quang ngoc tran Thi Dieu Hien Pham Thi Hoai nguyen Ba Huy Pepper Research and Development Centre Pleiku City Viet Nam

Black pepper varieties, namely “Vinh Linh”, “Lada”, “An Do” and “Loc Ninh” were planted in three different ecological regions: Dak Lak, Gia Lai and Dong Nai in order to compare the growth ability, productivity, and quality of peppercorn. The experiments were designed in the Randomized Complete Block Design (RCBD) with four replications. The results of study have been indicated that “Vinh Linh” and “Lada” both varieties performed better crucial parameters of growth, productivity and yield, after 36 months planted. Although having greater growth parameter in the location of Dong Nai province, four varieties showed lower yield than other regions. By contrast, the four pepper types achieved the highest yield in Gia Lai, followed by Dak Lak. With respect to peppercorn quality, “Vinh Linh”, “Loc Ninh” and “Lada” achieved requirements of Vietnamese Standard (TCVN 7036:2008) including bulk density: 535.69 - 612.72 g/l;piperine: 4.06 - 4.31 g/100g and volatile oil at 2.72 - 3.16 ml/100g. In contrast, “An Do” variety presented the poorest level of piperine (3.78 g/100g), and unachieved requirements.

关键词： Pepper Varieties Growth Yield Ecology Vietnam

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

Enhancement of Performance of Organic Light Emitting Diodes by Using Ti- and Mo-Oxide Nano Hybrid Layers

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Materials Sciences and Applications 2013年第4期4卷 275-280页

作者： nguyen Nang Dinh Do ngoc Chung tran Thi Thao tran Thi Chung Thuy Le Ha Chi Vo-Van Truong Department of Physics Concordia University Montreal Canada Institute of Materials Science Vietnamese Academy of Science and Technology Hanoi Vietnam University of Engineering and Technology Vietnam National University Hanoi Hanoi Vietnam Water Resources University Hanoi Vietnam

Nanorod-like TiO2 (nc-TiO2) and MoO3 (nc-MoO3) films were thermally grown from Ti- and Mo-metallic wafers. Nanohybrid films of N,N’-diphenyl-N,N’-bis(1-naphthyl)(1,1’-biphenyl)-4,4’diamine (NPB)/TiO2 and NPB/MoO3 used as anode/hole transport layer (HTL) heterojunctions in blue organic light emission diodes (OLEDs) were prepared by coating NPB onto the nc-TiO2 and nc-MoO3 and TiO2. Characterization of the nanostructured hybrid layers showed that both the photoluminescent property and current-voltage (I-V) characteristics of the hybrid materials were significantly enhanced in comparison with the standard NPB polymer. The electroluminous efficiency of the hybrid devices was considerably enhanced in comparison with the standard device. This suggests a useful application for fabricating “reverse” OLEDs, where the emission light goes-out through the semitransparent cathode, instead of the indium tin oxide (ITO) anode. For this, the ohmic contacts of conducting wires to metallic electrodes can be made much better than to ITO anodes.

关键词： Organic Light Emitting Diodes (OLED) Hybrid Heterojunctions Curent-Voltage (I-V) Characteristic Luminous Efficiency