检索结果-南通市图书馆

A novel approach for synthesis of hierarchical mesoporous Nd2O3 nanomaterials

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

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

Facile synthesis of FeFe2O4 magnetic nanomaterial for removing methylene blue from aqueous solution

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2019年第6期29卷 648-654页

作者： Van-Phuc dinh Ngoc Quyen Tran Nguyen-Que-Tran Le Quang-Huy Tran trinh Duy Nguyen Gr EEN), Nguyen Tat Thanh University Van Tan Le Future Materials and Devices Laboratory Institute of Fundamental and Applied Sciences Duy Tan University Institute of Applied Materials Science VAST Graduate University of Science and Technology VAST Le Quy Don–LBT Highschool Bien Hoa City Dong Nai province Center of Excellence for Green Energy and Environmental Nanomaterials (CE Industrial University of Ho Chi Minh City

A facile and simple chemical precipitation method was utilized to synthesize FeFe2O4magnetic nanomaterial for removing methylene blue（MB） from aqueous solution. Characterizations of this material were examined by using XRD, SEM, FT-IR, TGA-DTG and BET methods. Factors affecting the uptake of methylene blue, including p H, adsorption time, and MB initial concentration were also studied. The measured data were fitted by using four isotherm models including Langmuir, Freundlich, Sips and Temkin. Results showed that the Sips model offers the best fit to the data. In addition, the monolayer MB adsorption capacity obtained from the Langmuir model was 42.35 mg g-1under the optimal conditions of p H = 10 and adsorption time = 80 min. In particular, the uptake of MB onto FeFe2O4magnetic nanomaterial obtained from the kinetic and mechanism studies of the adsorption was in good agreement with prediction of the pseudo-first-order model, whereas the electrostatic interaction was found to play a primary mechanism.

关键词： FeFe2O4 magnetic nanomaterial Adsorption Methylene blue Adsorption mechanism

不同围岩条件下偏压隧道初期支护优化设计研究——以鹤大高速公路回头沟隧道为例

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

不同围岩条件下偏压隧道初期支护优化设计研究——以鹤大高速公路...

作者： NGUYEN dinh hoan（阮庭环）吉林大学

学位级别：硕士

由于偏压隧道的复杂性,通过工程类比法设计出的初期支护在实际工程的施工和运营期间出现了许多问题,因此对于地形偏压隧道的初期支护结构有必要进行深入的研究、优化设计。本文结合在建隧道的浅埋偏压段,通过资料调研、理论分析和数值... 详细信息

由于偏压隧道的复杂性,通过工程类比法设计出的初期支护在实际工程的施工和运营期间出现了许多问题,因此对于地形偏压隧道的初期支护结构有必要进行深入的研究、优化设计。本文结合在建隧道的浅埋偏压段,通过资料调研、理论分析和数值模拟对偏压隧道的初期支护体系提出锚杆长度、锚杆间距和喷混凝土厚度的优化设计。本文采用MIDAS/GTS/NX有限元数值模拟软件建立二维数值模型,根据原设计方案与《公路隧道设计规范》(JTG D70-2004)设计出锚杆长度、间距以及喷射混凝土层厚度的各个工况,进行模拟分析研究,最终结合工程经济性做出优化设计。通过研究得出以下成果:1.根据回头沟隧道工程地质条件,几何参数和围岩的物理力学特性建立了相应的数值模拟模型,利用数值方法对偏压隧道初期支护进行了模拟分析。给出了各设计工况产生的隧道特征位移、衬砌轴应力与弯矩、围岩塑性区、锚杆轴力等,并对其进行研究分析。最终给出回头沟隧道IV级和V级围岩条件下初期支护的优化设计方案。2.分析比较了埋深为5m,10m,15m,地表倾角为15°,30°,45°各组合条件下,隧道不同初期支护设计的支护效果,通过比较塑性区分布情况以及围岩压力,周围位移,衬砌受力,可知:(1)对于偏压隧道,埋深和地表倾角均会影响到隧道初期支护的受力,因此要综合考虑隧道的埋深和地表倾角。(2对于偏压隧道,采用非对称的支护结构设计较对称设计更为合理。3.依据优化方案,对该隧道的施工进行指导,保障其安全与稳定。

关键词：偏压隧道初期支护不同围岩级别优化设计

High burden of hepatocellular carcinoma and viral hepatitis in Southern and Central Vietnam:Experience of a large tertiary referral center,2010 to 2016

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

World Journal of Hepatology 2018年第1期10卷 116-123页

作者： Song-Huy Nguyen-dinh Albert Do Trang Ngoc Doan Pham Doan Y Dao trinh Nhu Nguy Moon S Chen Jr Liver Tumor DepartmentCho Ray HospitalHo Chi Minh City 700000Vietnam Department of Internal Medicine Yale UniversityNew HavenCT 06510United States School of Public Health University of IllinoisChicagoIL 60302United States Division of Digestive and Liver Diseases UT Southwestern Medical CenterDallasTX 75390United States Vietnam Viral Hepatitis Alliance Ho Chi Minh City 7000Vietnam Davis Comprehensive Cancer Center University of CaliforniaSacramentoCA 95817United States

AIM To examine the largest tertiary referral center in southern and central Vietnam from 2010 to 2016, evaluating epidemiological trends of hepatocellular carcinoma(HCC) and viral hepatitis B-C in this resource-limited *** We extracted data of patients receiving care from Cho Ray Hospital(Ho Chi Minh City), the largest oncology referral center in southern and central Vietnam, from 2010 to 2016. We collected information on patient age, gender, geographic distribution, and disease characteristics including disease stage, tumor biomarker levels [serum alpha-fetoprotein(AFP), AFP-L3 isoform percentage, and prothrombin induced by induced by vitamin K absence-Ⅱ], and serological testing for hepatitis B virus(HBV) and hepatitis C virus(HCV) *** Data from 24091 HCC patients were extracted, with sample demographics comprising mostly male(81.8%) and older age(however with 8.5% younger than 40 years old). This patient sample included a geographic catchment population of 56 million people(60% of the country's total population of 92.7 million), derived from 38 provinces and municipalities in Vietnam. Chronic HBV infection was found in 62.3% of cases, and chronic HCV infection in 26.0%. HBV and HCV co-infection was seen in 2.7%. Cirrhosis was found in an estimated 30% to 40% of cases. Nine percent of patients were not found to have chronic viral hepatitis. Twenty three point two percent of the patients had a normal AFP level. A total of 2199 patients were tested with AFP-L3 and PIVKA Ⅱ over two years, with 57.7% having elevated AFP-L3%, and 88.5% with elevated PIVKA Ⅱ levels. Over this 7-year period, the incidence of HCC increased, with a large proportion of cases(overall 40.8%) presenting initially an advanced stage, not amendable to surgical or locoregional *** HCC contributes significant health care burden in southern and central Vietnam, with increasing case volume over this seven-year period. Viral hepatitis likely explains this high

关键词： Hepatocellular carcinoma Hepatitis B virus Hepatitis C virus Alpha-fetoprotein

20-Hydroxyecdysone from Dacrycarpus imbricatus bark inhibits the proliferation of acute myeloid leukemia cells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2017年第2期10卷 151-153页

作者： trinh Thi Thuy Nguyen Thanh Tam Nguyen Thi hoang Anh Dang Viet Hau dinh Thi Phong Le Quoc Thang Sabrina Adorisio Tran Van Sung Domenico V Delfino Institute of Chemistry Vietnam Academy of Science and Technology Vietnam National Museum of Nature Vietnam Academy of Science and Technology Hue University’s College of Educations Section of Pharmacology Department of MedicineUniversity of Perugia

Objective:To investigate the anti-proliferative effects of 20-hydroxyecdysone isolated from the bark of Dacrycarpus imbricatus(Blume) de ***:Column chromatography was used for isolation of compounds from plant *** structure of the isolated compound was identified by mass spectrometry and nuclear magnetic resonance techniques,including HSQC,HMBC,NOE-difference *** isolated compound was tested for its anti-proliferative activity in acute myeloid leukemia(AML) and OCI-AML ***:Compound 1 was isolated from the ethyl acetate fraction of Dacrycarpus imbricatus barks by column *** chemical structure was identified as 20-hydroxyecdysone(20HE),a cholestane-type ecdysteroid,by a combination of mass spectrometry and nuclear magnetic resonance spectrometric *** goal was to test the anti-proliferative activity of 20 HE using the OCI-AML cell line.20 HE significantly decreased OCI cell number at a concentration of 1 mg/mL,whereas lower concentrations were ***,this decrease was due to partial blockage of the G_1/S phase of the cell cycle,with a reduction of cells in the G_2M phase,not due to increased ***:This indicates that 20 HE significantly decreases the number of cells in the G_1/S phase of the cell cycle in human AML *** is the first time that the anti-proliferative activity of 20 HE against a human tumor cell line has been reported.

关键词： Dacrycarpus imbricatus Ecdysteroid 20-hydroxyecdysone Proliferation Acute myeloid leukemia

Novel Time Series Bagging Based Hybrid Models for Predicting Historical Water Levels in the Mekong Delta Region, 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

Computer Modeling in Engineering & Sciences 2022年第6期131卷 1431-1449页

作者： Nguyen Thanh hoan Nguyen Van Dung Ho Le Thu Hoa Thuy Quynh Nadhir Al-Ansari Tran Van Phong Phan Trong trinh Dam Duc Nguyen Hiep Van Le Hanh Bich Thi Nguyen Mahdis Amiri Indra Prakash Binh Thai Pham Institute of Geography Vietnam Academy of Science and TechnologyHanoi10000Viet Nam Department of Civil Environmental and Natural Resources EngineeringLulea University of TechnologyLulea97187Sweden Institute of Geological Sciences Vietnam Academy of Science and Technology(VAST)Dong DaHanoi10000Viet Nam University of Transport Technology Thanh XuanHa Noi10000Viet Nam Department of Watershed&Arid Zone Management Gorgan University of Agricultural Sciences&Natural ResourcesGorgan***Iran DDG(R)Geological Survey of India Gandhinagar382010India

Water level predictions in the river,lake and delta play an important role in flood *** year Mekong River delta of Vietnam is experiencing flood due to heavy monsoon rains and high *** subsidence may also aggravate flooding problems in this ***,accurate predictions of water levels in this region are very important to forewarn the people and authorities for taking timely adequate remedial measures to prevent losses of life and *** are so many methods available to predict the water levels based on historical data but nowadays Machine Learning(ML)methods are considered the best tool for accurate *** this study,we have used surface water level data of 18 water level measurement stations of the Mekong River delta from 2000 to 2018 to build novel time-series Bagging based hybrid ML models namely:Bagging(RF),Bagging(SOM)and Bagging(M5P)to predict historical water levels in the study *** of the Bagging-based hybrid models were compared with Reduced Error Pruning Trees(REPT),which is a benchmark ML *** data of 19 years period was divided into 70:30 ratio for the *** data of the period 1/2000 to 5/2013(which is about 70%of total data)was used for the training and for the period 5/2013 to 12/2018(which is about 30%of total data)was used for testing(validating)the *** of the models was evaluated using standard statistical measures:Coefficient of Determination(R2),Root Mean Square Error(RMSE)and Mean Absolute Error(MAE).Results show that the performance of all the developed models is good(R2>0.9)for the prediction of water levels in the study ***,the Bagging-based hybrid models are slightly better than another model such as ***,these Bagging-based hybrid time series models can be used for predicting water levels at Mekong data.

关键词： Computational techniques bagging water level time series algorithms

Assessing the Vulnerability of Agricultural Production Activities in the Coastal Area of Thua Thien Hue Province, Vietnam by GIS Analysis Tools

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geoscience and Environment Protection 2019年第5期7卷 116-130页

作者： Nguyen hoang Son Dao dinh Cham Phan Anh Hang Nguyen Trong Quan Nguyen Thanh hoan University of Education Hue University Hue Vietnam Institute of Geography Vietnam Academy of Science and Technology Hanoi Vietnam Graduate University of Science and Technology Vietnam Academy of Science and Technology Hanoi Vietnam University of Science Hue University Hue Vietnam

Using Geography Information System (GIS) tools and remote sensing data in assessing the level of vulnerability of agricultural production activities in the coastal area has become more efficient in the recent years. This research has identified the sensitivity index (S) (including the traffic access index;the impact of residential areas;the impacts of industrial zones;the community dependence level), exposure index (E) (the sea level rises to 2100;the temperature change to 2100), the adaptable capacity index (AC) (slope;morphology), thereby synthesizing the vulnerability index (V). Based on the indexes to calculate vulnerability, the high to very high vulnerability area is 37,081.44 ha, accounting for 68.09%;the average vulnerability level is 15,286.49 ha, accounting for 28.07%;the low to very low vulnerability level with an area is 2087.82 ha, accounting for 3.84% of the total area. With a high and very high vulnerability accounting for 68.09%, there will be great influences on the lives of resident in the area, especially agricultural production.

关键词： Vulnerability Indexes GIS Tools Agricultural Production Activity Coastal Areas

Assessment of Radiation Dose Caused by Radioactive Gaseous Effluent Released from Nuclear Power Plant Ninh Thuan 1 under Scenario of Normal Working Conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Nuclear Science and Technology 2015年第3期5卷 183-191页

作者： Nguyen Tuan Khai Do Xuan Anh Le dinh Cuong Duong Duc Thang Vuong Thu Bac Nguyen Thi Thu Ha Nguyen Quang Long trinh Van Giap Nguyen Hao Quang Institute for Nuclear Science and Technology (INST) Hanoi Vietnam Vietnam Atomic Energy Institute (VINATOM) Hanoi Vietnam

Based on guides RG 1.109, RG 1.111 published by United States Nuclear Regulatory Commission (USNRC), our research concentrates in assessing radiation doses caused by radioactive substances released from the nuclear power plant (NPP) Ninh Thuan 1 under the scenario of normal operation using software package NRCDose72 provided by the USNRC. The database including the released radioactive nuclides, meteorology, terrain, population and agricultural production activities have been collected and processed to build the input data for the model calculation. The wind rose distribution obtained from the meteorological data in a five-year period from 2009-2013 showed that the radioactive nuclides released to environment spread in two main wind directions which are North East and South West. The X/Q (s/m3) and D/Q (s/m2) qualities which are, respectively, the ratio of activity concentration to release rate and that of deposition density of radioactive nuclides to release rate were calculated within an area of 80 km radius from the NPP site using XOQDOQ. Population doses were calculated using GASPAR. The XOQDOQ and GASPAR are two specific softwares in NRCDose72 package.

关键词： NPP Radioactive Release Radiation Dose Population Dose X/Q and D/Q

Spatio-Temporal Determination of Irrigated Paddy Rice Pixels Using Evapotranspiration and Vegetation Indices: A Case Study for Ca River Basin 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

Journal of Geoscience and Environment Protection 2020年第12期8卷 94-107页

作者： Chung N. Luong Lan T. Ha Thanh C. Pham Hung X. dinh Thanh T. hoang hoan N. Nguyen Tuan V. Nguyen Phung X. Nguyen Institute of Water Resources Planning Hoan Kiem Hanoi Vietnam Division of Water Resources Planning in Northern Central Region Institute of Water Resources Planning Hoan Kiem Hanoi Vietnam Department of Training and International Cooperation Institute of Water Resources Planning Hoan Kiem Hanoi Vietnam Division of Hydro-Meteorology Institute of Water Resources Planning Hoan Kiem Hanoi Vietnam

Improving irrigation monitoring and efficiency is a current priority of the Government of Vietnam, focusing primarily on the agricultural sector which consumes most of the available surface and groundwater. This paper presents how remote sensing can be used in an integrated manner to achieve better understanding of key eco-hydrological processes including precipitation, evapotran-spiration, irrigation and crop growth. The results indicated that Normalized Difference Vegetation Index derived from Moderate Resolution Imaging Spectroradiometer (MODIS) can be applied to determine irrigated pixels on a spatial and temporal basis. The validation using measured water level showed a Pearson correlation of 0.7 proving the high accuracy of this method. The inclusion of these technologies is deemed necessary to improve water resources monitoring and management and hence, ensure long-term drought resilience and water and food security. Ca River Basin in the central Vietnam was selected as a case study to test this approach.

关键词： Remote Sensing Drought Management Irrigated Paddy