检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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

SOME PRELIMINARY RESULTS FROM STUDY OF CRUSTAL DEFORMATION IN vietNAM

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

大地测量与地球动力学 2003年第B12期23卷 114-118页

作者： Cao Dinh Trieu Le Van Dung Nguyen Huu tuyen Pham Nam Hung Institute of Geophysics Institute of GeophysicsInstitute of GeophysicsInstitute of Geophysics 18 Hoang Quoc Viet Road Cau GiayHanoi18 Hoang Quoc Viet Road Cau GiayHanoi18 Hoang Quoc Viet Road Cau GiayHanoi18 Hoang Quoc Viet Road Cau GiayHanoi

In this work, the authors present some results of strain monitoring within the territory of vietnam from 1984 to 2001. Data analysis shows that (1) the Phu Lien area is tectonically stable with low strain rate, 1×10\+\{-6\} /a; (2) the Hoa Binh area has indication of tectonic instability with relatively high strain rate of the earth crust: absolute value of the strain reaching 100×10\+\{-6\}, usual average strain amplitude of 60×10\+\{-6\}, whereas the monthly average strain intensity varies in a range from 30×10\+\{-6\} to 50×10\+\{-6\}; (3) there are clear indications of the strain state of the earth crust before occurrence of earthquakes of medium or higher magnitude. This is a very important indication in the research and short term prediction of earthquakes, especially for the areas with low seismic stability like the NW of vietnam.

关键词：越南表层变形应变测量系统操作原则应变数据因变与地震相对关系地震活动特性

Calculation of the ex-core neutron noise induced by individual fuel assembly vibrations in two PWR cores

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2016年第4期27卷 67-77页

作者： Kiet A.T.Hoang Van-Chung Cao Van-Khanh Hoang hoai-nam tran Institute of Research and Development Duy Tan University K7/25 Quang Trung Da Nang Vietnam American Polytechnic College Trung Son KDC Binh Chanh HCMC Vietnam Research and Development Center for Radiation Technology VINATOM Thu Duc HCMC Vietnam Faculty of Physics and Engineering Physics VNUHCM University of Science HCMC Vietnam Institute for Nuclear Science and Technology VINATOM 179 Hoang Quoc Viet Hanoi Vietnam

Calculation of the neutron noise induced by fuel assembly vibrations in two pressurized water reactor(PWR) cores has been conducted to investigate the effect of cycle burnup on the properties of the ex-core detector noise. An extension of the method and the computational models of a previous work have been applied to two different PWR cores to examine a hypothesis that fuel assembly vibrations cause the corresponding peak in the auto power spectral density(APSD) increase during the cycle. Stochastic vibrations along a random two-dimensional trajectory of individual fuel assemblies were assumed to occur at different locations in the cores. Two models regarding the displacement amplitude of the vibrating assembly have been considered to determine the noise source. Then, the APSD of the ex-core detector noise was evaluated at three burnup steps. The results show that there is no monotonic tendency of the change in the APSD of ex-core detector; however, the increase in APSD occurs predominantly for peripheral assemblies. When assuming simultaneous vibrations of a number of fuel assemblies uniformly distributed over the core, the effect of the peripheral assemblies dominates the ex-core neutron *** behaviour was found similar in both cores.

关键词：燃料组件随机振动中子噪声计算模型压水堆堆芯功率谱密度压水反应堆

Biomass accumulation of Panax vietnamensis in cell suspension cultures varies with addition of plant growth regulators and organic additives

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2017年第9期10卷 907-915页

作者： Tuan tran Trong Dieu-Hien Truong Hoang Chinh Nguyen Dieu-Thai tran Huyen-trang Nguyen Thi Giap Do Dang Ho Nguyen Huu Plant Cell Technology Department Institute of Tropical BiologyVietnam Academy of Science and Technology9/621 Ha Noi HighwayLinh TrungThu DucHo Chi Minh CityViet Nam Faculty of Applied Sciences Ton Duc Thang University19 Nguyen Huu ThoTan PhongDistrict 7Ho Chi Minh CityViet Nam Genetic Engineering Department Institute of Tropical BiologyVietnam Academy of Science and Technology9/621 Ha Noi HighwayLinh TrungThu DucHo Chi Minh CityViet Nam

Objective: To evaluate the impact of plant growth regulators including kinetin(KN),benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of vietnamese ginseng Panax vietnamensis(P. vietnamensis) in cell suspension ***: Cell suspension cultures were established from friable calluses derived from leaves and petioles of 3-year-old in-vitro P. vietnamensis plants. The cell suspension cultures were grown in Murashige and Skoog basal media supplemented with various concentrations of KN, benzyl adenine, naphthalene acetic acid, and yeast extract and casein ***: All tested factors generated an increase in the cell biomass of P. vietnamensis in suspension culture, but the impact of each varies depended on the factor type, concentration, and incubation period. Addition of 2.0 mg/L KN resulted in the largest biomass increase after 24 d,(57.0 ± 0.9) and(3.1 ± 0.1) mg/m L fresh and dry weight, respectively,whereas addition of benzyl adenine or naphthalene acetic acid produced optimum levels of Panax cell biomass at 1.0 and 1.5 mg/L, respectively. Addition of the elicitor yeast extract led to a 1.4–2.4 fold increase in biomass of P. vietnamensis, while addition of casein hydrolyzate enhanced biomass accumulation 1.8–2.6 ***: The addition of each factor causes significant changes in biomass accumulation of P. vietnamensis. The largest biomass accumulation is from cultures grown in MS media containing 2.0 mg/L KN for 24 d. The outcome of the present study provides new insights into the optimal suspension culture conditions for studies on the in vitro cell biomass production of P. vietnamensis.

关键词： Panax vietnamensis Plant cell suspension culture Plant regulators Yeast extract Casein hydrolyzate Biomass

Phytochemical Constituents and Determination of Resveratrol from the Roots of Arachis hypogeaL.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2013年第12期4卷 2351-2358页

作者： tuyen Pham Nguyen Kim Nga Vo Thi Phuong tran Van Phuong Quach Ngo Diem Duong Ngo Thi Thuy Quang Ton That Phung Nguyen Kim Phi Department of Chemical Technology Faculty of Chemical-Food Technology University of Technical Education Ho Chi Minh City Ho Chi Minh City Vietnam Department of Organic Chemistry Faculty of Chemistry University of Science Vietnam National University-Ho Chi Minh City Ho Chi Minh City Vietnam Department of Plant Biotech and Biotransformation Faculty of Biology University of Science Vietnam National University-Ho Chi Minh City Ho Chi Minh City Vietnam Faculty of Environmental Science Sai Gon University Ho Chi Minh City Vietnam

Two triterpenoid saponins, 6, 7, together with five known compounds were isolated from the roots of Arachis hypogea L. collected in vietnam. Their structures were established by spectroscopic analysis (1D, 2D NMR and HRMS) as well as by comparison with those reported in the literature. Furthermore, the high content of resveratrol in the roots opens a new potential resource for pharmaceutical companies to prepare medicines from the wasted peanut roots.

关键词： Arachis hypogea L. Peanut Resveratrol Triterpenoid Glycoside

基于多传感特征信息融合的采煤机截齿失效诊断

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国机械工程 2016年第17期27卷 2334-2340页

作者：张强王海舰李立莹闻学震阮越宣辽宁工程技术大学阜新123000 大连理工大学工业装备结构分析国家重点实验室大连116023 煤矿与机械能源研究院河内越南100000

针对采煤机截割头截割过程中截齿失效状态不易在线识别的难题,提出了一种基于多传感特征信息融合的采煤机截齿失效诊断方法。通过测试采煤机不同磨损程度状态的截齿在截割过程中的振动信号以及声发射信号,建立截齿损耗和失效的信号特征... 详细信息

针对采煤机截割头截割过程中截齿失效状态不易在线识别的难题,提出了一种基于多传感特征信息融合的采煤机截齿失效诊断方法。通过测试采煤机不同磨损程度状态的截齿在截割过程中的振动信号以及声发射信号,建立截齿损耗和失效的信号特征数据库,采用基于最小模糊隶属度优化模型的多传感信息融合方法诊断采煤机截齿的磨损及失效状态。实验结果表明诊断结果的准确率可达95%以上,证明采用此方法可实现对采煤机截齿磨损程度及失效状态的实时精确诊断。研究结果对及时发现和更换失效截齿、提高采煤机截割头的工作效率和使用寿命具有重要意义。

关键词：采煤机截齿失效声发射信息融合模糊隶属度

Study the Changes in Soil Organic Carbon of Rice-Maize Cropping System in the Top Layer of Alluvisol Soil in Dan Phuong: A Study of C-13 Stable Isotope Composition (δ13C)

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Protection 2019年第10期10卷 1361-1372页

作者： Nguyen Thi Hong Thinh Vu Hoai Ha Lan Anh Vo Thi Anh Truong viet Chau Trinh Van Giap tran Minh Tien Isotope Hydrology Laboratory Institute for Nuclear Science and TechnologyHanoiVietnam Soils and Fertilizers Research Institute HanoiVietnam

In this study, the experiments on field were conducted to examine the change in the content of soil organic carbon (SOC), its C-13 stable isotope composition (δ 13C) and some main physical, chemical parameters (soil moisture, pH, soil density, content of humic, fulvic, total N, total P, total K) in alluvial soil of Dan Phuong region—vietnam at a depth of 0 - 30 cm when we changed the regime from 2 maize -1 rice crop to 2 rice - 1 maize crop per 1 year. In addition to analyzing the main parameters in soil, C content and its δ 13C value in parts of rice and maize (root, stem and leaf) were also analyzed to assess the contribution of plant residues on soil organic carbon content after harvest. The experiment was carried out in 2016-2017 on the field with the traditional farming method of local farmers along with the tropical monsoon weather conditions of the North-vietnam. The results showed that SOC had positive correlation with total N, total P parameters and negative correlation with δ 13C values of soil samples at two layers (0 - 15 cm and 15 - 30 cm). The average of total dry biomass (stem, stump + roots and leaf parts) per 1 rice and 1 maize crop was 10.64 Mg/ha and 9.09 Mg/ha, respectively. The average of δ 13C value of rice (C3 plant) was -29.78‰ and its value of maize (C4 plant) was -12.61‰. The new plant (rice) contributes to the total soil organic carbon content from 11.31% to 44.14% at the 0 - 15 cm layer and from 6.55% to 11.31% at the 15 - 30 cm layer in one-year experiment period.

关键词： Soil Organic Carbon (SOC) C-13 Stable Isotope Maize and Rice Crop Soil Properties

Evaluation of the calibration factors of neutron dose rate meters in a 241Am–Be neutron field

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2019年第9期30卷 18-23页

作者： Thiem Ngoc Le Sy Minh Tuan Hoang Quynh Ngoc Nguyen Hoai-Nam tran Institute for Nuclear Science and Technology VINATOM 179 Hoang Quoc Viet Hanoi Vietnam Institute of Fundamental and Applied Sciences Duy Tan University Ho Chi Minh City Vietnam

Calibrations were performed for three types of neutron ambient dose equivalent rate meters, i.e., Aloka TPS-451C (Hitachi), KSAR1U.06 (Baltic Scientific Instruments), and Model 12-4 (Ludlum), using a standard field of a 241Am–Be source. The measured total neutron ambient dose equivalent rates, H*(10)' tot, were analyzed to obtain the direct neutron ambient dose equivalent rates, H*(10)' dir, using the ISO 8529-2-recommended generalized- fit method, semiempirical fit method, and reducedfitting method (RFM) fit methods. The calibration factor (CF), defined as the ratio between the conventional true value of the neutron ambient dose equivalent rates in a free field, H*(10)' FF, and H*(10)' dir, was evaluated as one of the important characteristics of the neutron meters in the present work. The fitting results show that the H*(10)' dir values of the meters are in good agreement within the theoretical data within 4%. The averaged CFs of the three neutron meters were evaluated as 0:99 ± 0:01, 1:00 ± 0.03;and 0:99 ± 0:08, respectively. The largest standard uncertainty of these values was determined to be approximately 18.47%(k =1). The standard uncertainty of the CFs obtained using the RFM method was less than 4.23%(k=1), which is the smallest uncertainty among the three methods.

关键词： Neutron meter Calibration factor ^241 Am–Be source

Applied Biofloc Technology for Target Species in the Mekong Delta in vietnam： A Review

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Science and Engineering(B) 2017年第4期6卷 165-175页

作者： Nguyen Van Hoa Ta Van Phuong tran Ngoc Hai Chau Tai Tao Le Quoc viet Nguyen Thi Hong Van Huynh Thanh Toi tran Huu Le Vo Nam Son Pham Quoc Anh Duy College of Aquaculture and Fisheries (CAF) Cantho University Cantho 270000-910000 Vietnam College of Applied Biology Tay Do University Cantho 270000-910000 Vietnam

BFT （Biofloc Technology） has been currently applied in Cantho University to a number of targeted species from fresh-to marine and saline water species in the Mekong Delta, e.g. striped catfish （Pangasianodon hypophthalmus）, white leg shrimp （Litopenaeus vannamei）, tiger shrimp （Penaeus monodon） and Artemia Vinhchau strain （Artemia franciscana） for both in the lab-scales or production scales. The best growth and survival rate of striped catfish was obtained in 6%o. For white leg shrimp, the results indicated：（1） C （Carbon） source e.g. rice-flour or molasses supplementary based on the feed provided to promote survival, growth and shrimp biomass harvested; （2） it was fed less than 20% as usual but showed similar to those in the control; （3） combination of rice-flour and molasses at a ratio of 70：30 by weight of C and N （Nitrogen） in a ration of 15：1 enhanced shrimp survival and growth; （4） in intensive culture, shrimp could be against the infection of disease and end up with higher survival, growth in earthen ponds. For tiger shrimp, a set up for larvae till post larvae at different ratios of C and N and C：N of 30 PLI5 displayed with better survival rate （49.73 ± 7.07%） and production （74,596 ± 10.608 PL/m3）. Artemiafranciscana was set up at C：N = 10：1 and salinities from 35, 60, 80 and 100 ppt. After two weeks, there were no significant difference among treatment and the control （without biofloc） in term of survival and growth. Moreover, total embryos per female was not significant different with the control and even the number of embryos as cysts tended to be higher. BFT displayed its advantages when applied on culture system of different targeted species and there is no doubt that it could help to sustain aquaculture and save environment in the Mekong Delta in near future.

关键词： Biofloc techology striped catfish white leg shrimp tiger shrimp Artemia Vinhchau strain.