检索结果-南通市图书馆

Salinity Effect at Seedling and Flowering Stages of Some Rice Lines and Varieties(Oryza sativa L.)

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 Agricultural Science and Technology(A) 2017年第B10期7卷 32-39页

作者： tran thi Huong Sen Phan thi phuong Nhi Trinh thi Sen Faculty of Agronomy University of Agriculture and ForestryHue University102 Phung Hung StreetHue 530000Vietnam

this study used 10 rice lines and varieties,including the salt tolerant variety(Pokkali)and salt susceptible variety(IR29)as *** for screening rice salinity tolerance at seedling stage was conducted in hydroponic system using five different salinity concentrations(0,4,6,8 and 10 dS/m).Flowering stage was evaluated at the salinity level of 8 dS/*** experiment was designed in randomized completely block(RCBD)with three replications for each line/variety under non-saline and saline *** results showed that the growth of rice lines/varieties was retarded severely with increasing salinity levels,and almost all of leaves were drying and dead completely(score 7 and 9).Plants of IR29 and OM7347 were dead at the electrical conductivity(EC)=10 dS/m,whereas Pokkali(the tolerant variety)and IR93350 were evaluated at score *** stress caused the reduction of overall vigor of rice lines/varieties especially in the pollen germination,fertilization and grain *** lines/varieties were classified to salinity tolerance levels as following:IR5040,IR93350,IR86385-8D-1-2-B and Pokkali(tolerant);OM8104,IR93340 and IR93343(moderate susceptible);OM7347,IR87832-303-1-B and IR29(susceptible).

关键词： Tolerant salinity pollen seedling stage flowering stage screening for salinity tolerance

ALMA observations of the circumstellar envelope around EP Aqr

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2019年第3期19卷 97-110页

作者： Pham thi Tuyet Nhung Do thi Hoai Pham Tuan-Anh thibaut Le Bertre Pierre Darriulat Pham Ngoc Diep Nguyen thi phuong Nguyen thi Thao Jan Martin Winters Department of Astrophysics Vietnam National Space CenterVAST LERMA UMR 8112 CNRS and Observatoire de Paris PSL Research University Graduate University of Science and Technology VAST IRAM 300 rue de la Piscine Domaine Universitaire

Atacama Large Millimetre/sub-millimetre Array(ALMA) observations of CO(1–0) and CO(2–1) emissions from the circumstellar envelope of the asymptotic giant branch(AGB) star EP Aqr have been made with four times better spatial resolution than previously available. They are analysed with emphasis on the de-projection in space of the effective emissivity and flux of matter using as input a prescribed configuration of the velocity field, assumed to be radial. The data are found to display an intrinsic axisymmetry with respect to an axis making a small angle with respect to the line of sight. A broad range of wind configurations, from prolate(bipolar) to oblate(equatorial) has been studied and found to be accompanied by significant equatorial emission. Qualitatively, the effective emissivity is enhanced near the equator to produce the central narrow component observed in the Doppler velocity spectra and its dependence on star latitude generally follows that of the wind velocity with the exception of an omni-present depression near the poles. In particular, large equatorial expansion velocities produce a flared disc or a ring of effective emissivity and mass loss. The effect on the determination of the orientation of the star axis of radial velocity gradients, and possibly competing rotation and expansion in the equatorial disc, is discussed. In general,the flux of matter is found to reach a broad maximum at distances of the order of 500 AU from the *** are given that may be used to favour one wind velocity distribution over another. As a result of the improved quality of the data, a deeper understanding of the constraints imposed on morphology and kinematics has been obtained.

关键词： stars: AGB and post-AGB (stars:) circumstellar matter stars: individual: EP Aqr stars:mass-loss radio lines: stars

Xanthine oxidase inhibitors from Archidendron clypearia(Jack.) I.C. Nielsen: Results from systematic screening of Vietnamese medicinal plants

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6期10卷 619-626页

作者： Nguyen Thuy Duong Pham Duc Vinh phuong thien Thuong Nguyen thi Hoai Le Nguyen Thanh tran The Bach Nguyen Hai Nam Nguyen Hoang Anh Department of Pharmacology Hanoi University of Pharmacy Department of Pharmaceutical Analysis and Standardization National Institute of Medicinal Materials Department of Pharmacognosy Hue University of Medicine and Pharmacy Institute of Marine Biochemistry Vietnam Academy of Science and Technology Institute of Ecology and Biological Resources Vietnam Academy of Science and Technology Department of Medicinal Chemistry Hanoi University of Pharmacy

Objective: To screen Vietnamese medicinal plants for xanthine oxidase(XO) inhibitory activity and to isolate XO inhibitor(s) from the most active plant. Methods: The plants materials were extracted by methanol. The active plant materials were fractionated using different organic solvents, including n-hexane, ethyl acetate, and n-butanol. Bioassay-guided fractionation and column chromatography were used to isolate compounds. The compounds structures were elucidated by analysis of spectroscopic data, including IR, MS, and NMR. Results: Three hundreds and eleven methanol extracts(CME) belonging to 301 Vietnamese herbs were screened for XO inhibitory activity. Among these plants, 57 extracts displayed XO inhibitory activity at 100 μg/m L with inhibition rates of over 50%. The extracts of Archidendron clypearia, Smilax poilanei, Linociera ramiflora and Passiflora foetida exhibited the greatest potency with IC_(50) values below 30 μg/m L. Chemical study performed on the extract of Archidendron clypearia resulted in the isolation of six compounds, including 1-octacosanol, docosenoic acid, daucosterol, methyl gallate, quercitrin and(-)-7-O-galloyltricetiflavan. The compound(-)-7-O-galloyltricetiflavan showed the most potent XO inhibitory activity with an IC_(50) value of 25.5 μmol/L. Conclusions: From this investigation, four Vietnamese medicinal plants were identified to have XO inhibitory effects with IC_(50) values of the methanol extracts below 30 μg/m L. Compound(-)-7-O-galloyltricetiflavan was identified as an XO inhibitor from Archidendron clypearia with IC_(50) value of 25.5 μmol/L.

关键词： Xanthine oxidase Inhibitor Medicinal plants Vietnam

Efficient Real-Time Devices Based on Accelerometer Using Machine Learning for HAR on Low-Performance Microcontrollers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第10期81卷 1729-1756页

作者： Manh-Tuyen Vi Duc-Nghia tran Vu thi Thuong Nguyen Ngoc Linh Duc-Tan tran Faculty of Electrical and Electronic Engineering Phenikaa UniversityHanoi City100000Vietnam Institute of Information Technology Vietnam Academy of Science and TechnologyHanoi City100000Vietnam Faculty of Information Technology and Communication Phuong Dong UniversityHanoi City100000Vietnam Graduate University of Sciences and Technology Vietnam Academy of Science and TechnologyHanoi City100000Vietnam International School–Vietnam National University Hanoi City100000Vietnam

Analyzing physical activities through wearable devices is a promising research area for improving health *** research focuses on the development of an affordable and real-time Human Activity Recognition(HAR)system designed to operate on low-performance *** system utilizes data from a bodyworn accelerometer to recognize and classify human activities,providing a cost-effective,easy-to-use,and highly accurate solution.A key challenge addressed in this study is the execution of efficient motion recognition within a resource-constrained *** system employs a Random Forest(RF)classifier,which outperforms Gradient Boosting Decision Trees(GBDT),Support Vector Machines(SVM),and K-Nearest Neighbors(KNN)in terms of accuracy and computational *** proposed features Average absolute deviation(AAD),Standard deviation(STD),Interquartile range(IQR),Range,and Root mean square(RMS).The research has conducted numerous experiments and comparisons to establish optimal parameters for ensuring system effectiveness,including setting a sampling frequency of 50 Hz and selecting an 8-s window size with a 40%overlap between *** was conducted on both the WISDM public dataset and a self-collected dataset,focusing on five fundamental daily activities:Standing,Sitting,Jogging,Walking,and Walking the *** results demonstrated high recognition accuracy,with the system achieving 96.7%on the WISDM dataset and 97.13%on the collected *** research confirms the feasibility of deploying HAR systems on low-performance microcontrollers and highlights the system’s potential applications in patient support,rehabilitation,and elderly care.

关键词： Accelerometer classification wearable computing activity recognition HAR

Luminescent and magnetic properties of multifunctional europium(Ⅲ) complex based nanocomposite

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 Rare Earths 2019年第11期37卷 1237-1241页

作者： Hoang thi Khuyen Nguyen Thanh Huong tran Thu Huong Pham thi Lien Do thi Anh Thu Nguyen thi Anh Huong Wieslaw Strek Le Quoc Minh Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc VietCau CiayHanoiViet Nam Graduate University of Science and Technology Vietnam Academy of Science and Technology18 Hoang Quoc VietCau GiayHanoiViet Nam Department of Chemistry University of Natural SciencesHanoi National University19 Le Thanh TongHoan KiemHanoiViet Nam Institute of Low Temperature and Structure Research PASOkolna 2Wroclaw 50-422Poland Duy Tan University K7/25 Quang TrungDa DangViet Nam

The luminescent rare earth(RE)complex based multifunctional nanocomposites offer new potential applications of multimodal imaging(magnetic resonance imaging(MRI),fluorescent bioimaging,etc.)that can be associated with therapeutic *** this study,we report some results obtained with novel multifunctional Fe3O4/Si-amine/Eu(NTA)3 nanocomposites that are composed of europium(Ⅲ)complex with 1-(2-naphthoyl)-3,3,3-trifluoroacetone ligands(NTA)(Eu(NTA)3)and superparamagnetic Fe3O4 *** nanocomposites were functionalized with an amine group for biomedicine *** multifunctional Fe3O4/Si-amine/Eu(NTA)3 nanocomposites exhibit both good magnetic behavior of Fe3O4 nanoparticles as a core and strong fluorescent property of europium(Ⅲ)*** characterizations were analyzed by XRD,SEM,EDX and FTIR *** optical properties were studied in detail by UV-VIS spectra and luminescent emission *** magnetic property was estimated by *** effect of concentrations of luminescent Eu(NTA)3 complex on luminescent and magnetic properties is discussed.

关键词： Multifunctional nanocomposite Luminescence Magnetic Europium(Ⅲ)complex Fe3O4 Rare earths

Synthesis and characterization of core/shell structured nanophosphors CePO_4:Tb@LaPO_4 by solvothermal method

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2011年第12期29卷 1147-1151页

作者： Dinh Xuan Loc tran thi Kim Chi tran Thu Huong Nguyen Vu tran Kim Anh Wieslaw Strek Le Quoc Minh Institute of Materials Science Vietnam Academy of Science and Technology Institute of Low Temperature and Structure Research Polish Academy of Sciences(PAN) University of Engineering and Technology

Core/shell structured CePO4：Tb（Ⅲ）@LaPO4 and CePOa：Tb（Ⅲ） were successfully synthesized in tris（2-ethylhexyl） phosphate （TEHP） and diethylene glycol （DEG） solvents for comparison of the two techniques in open air and closed reaction vessel. Morphology and crystal structure of the core/shell nanophosphors were determined by using X-ray diffraction （XRD） and transmission electron microscopy （TEM）, which showed that nanophosphors had diameter of about 5-10 nm with the monoclinic monazite phase. The nanophosphors obtained by close vessel procedure showed smaller size, more homogeneity and pure crystallite. The luminescent measurements were done upon the different excitation wavelengths in ultraviolet region and at room temperatm＇e to elucidate the influences of the used solvents and the reaction temperatures. It was found that CePO4：Tb@LaPO4 preparedby the close vessel synthesis showed the intensity of green band of the transfer from 5D4 to 7F5 energy level, which was strongly increased, and the luminescent decay time was 3.2 ms, which was longer than that of naked CePO4：Tb phosphor.

关键词： solvothermal synthesis luminescence CePOn:Tb CePOa:Tb@LaPO4 rare earths

A Simple Approach to the Fabrication of Graphene-Carbon Nanotube Hybrid Films on Copper Substrate by Chemical Vapor Deposition

在线全文

学校读者我要写书评

暂无评论

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

Assessment of different machine learning techniques in predicting the compressive strength of self-compacting concrete

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2022年第7期16卷 928-945页

作者： Van Quan tran Hai-Van thi MAI Thuy-Anh NGUYEN Hai-Bang LY Faculty of Civil Engineering University of Transport TechnologyHanoi 100000Vietnam

The compressive strength of self-compacting concrete(SCC)needs to be determined during the construction design *** paper shows that the compressive strength of SCC(CS of SCC)can be successfully predicted from mix design and curing age by a machine learning(ML)technique named the Extreme Gradient Boosting(XGB)algorithm,including non-hybrid and hybrid *** ML techniques,such as Linear regression(LR),K-Nearest Neighbors(KNN),Support Vector Machine(SVM),Decision Trees(DTR),Random Forest(RF),Gradient Boosting(GB),and Artificial Neural Network using two training algorithms LBFGS and SGD(denoted as ANN_LBFGS and ANN_SGD),are also compared with the XGB ***,the hybrid models of eight ML techniques and Particle Swarm Optimization(PSO)are constructed to highlight the reliability and accuracy of SCC compressive strength prediction by the XGB_PSO hybrid *** highest number of SCC samples available in the literature is collected for building the ML *** with previously published works’performance,the proposed XGB method,both hybrid and non-hybrid models,is the most reliable and robust of the examined techniques,and is more accurate than existing ML methods(R2=0.9644,RMSE=4.7801,and MAE=3.4832).Therefore,the XGB model can be used as a practical tool for engineers in predicting the CS of SCC.

关键词： compressive strength self-compacting concrete machine learning techniques particle swarm optimization extreme gradient boosting

Influence of different land-use types on selected soil properties related to soil fertility in A Luoi District,Thua thien Hue,Vietnam

在线全文

学校读者我要写书评

暂无评论

Soil Ecology Letters 2024年第1期6卷 131-140页

作者： Khoa Phuc Nguyen Tan Trong tran Huy Dinh Le phuong Thuy Nguyen Hien Thao thi Pham Dien Thanh Nguyen Ngu Huu Nguyen University of Agriculture and Forestry Hue UniversityHue CityThua Thien Hue 52000Vietnam School of Biotechnology Tan Tao UniversityTan Duc ECityDuc HoaLong An850000Vietnam

Land use type affects the physicochemical properties of *** value of OM and TN is high in acacia *** acidity of soil is considered a serious constraint for *** cash crops are acacia,cassava,banana,rice and *** fertility is affected by land-use types and land management,which exacerbates soil erosion and various other forms of soil degradation in the mountainous regions of *** study was conducted in A Luoi District,Thua thien Hue,Vietnam to identify the effects of land-use types on specific soil physicochemical characteristics related to soil *** physicochemical properties,such as organic matter(OM),total nitrogen(TN),total phosphorous(TP),and K+were significantly affected by land-use *** results showed that the soils were sandy in rice but clay loam for acacia and *** mean bulk density value of acacia soil was significantly greater than that of other *** were higher in the acacia soils than those in the rice,maize,and banana *** OM content was significantly higher in the acacia,cassava,and banana soils than those in the rice and maize *** mean of exchangeable K+in the rice soil was higher compared to those in other soils and was affected by land-use *** high exchangeable acidity content in the soils was probably due to intensive ***,both land use type and management did not affect the CEC ***,the inappropriate land use caused the disturbance of soil physicochemical properties,indicating that the conditions of rice and maize soils are becoming worse than acacia ***,lowering the intensity of cultivation,adopting incorporated soil fertility management,and applying organic fertilizer should preserve the existing conditions and enhance soil properties.

关键词： Land-use types soil characteristics soil frility suitable crop Vietnam