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Productivity Growth, Technological Progress, and Efficiency Change in Vietnamese Manufacturing Industries: A Stochastic Frontier Approach

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Open Journal of Statistics 2012年第2期2卷 224-235页

作者： nguyen Khac Minh Pham van khanh nguyen Thi Minh nguyen Thi Phuong Anh Faculty of Economics Water Resources University Hanoi Vietnam Hanoi University of Science and Technology Hanoi Vietnam Military Technical Academy Hanoi Vietnam National Economics University Hanoi Vietnam

This study applies a stochastic frontier production approach to decompose the sources of total productivity (TFP) growth into technical progress and changes in technical efficiency of 8057 firms in Vietnamese manufacturing industries during 2003-2007. Using both total manufacturing industry and sub-manufacturing industrial regressions, the analysis focuses on the trend of technological progress (TP) and technical efficiency change (TEC), and the role of productivity change in economic growth. According to the estimated results, the annual technical progress for the manufacturing industry and sub-manufacturing industries are calculated directly from the estimated parameters of the translog stochastic frontier production function by taking a partial derivative of output with respect to time t. The average technical changes in manufacturing industry and sub-manufacturing industries are positive, with an average technical change about 5.2%, 5.8%, 5.4%, 11.8%, 4.6%, 4.1%, 7.3%, 4.8%, 4.8% and 4.8% for total sample, food products & beverages, textile & wearing apparel, footwear, paper & products, industrial chemicals, rubber & plastic products, non- metallic mineral, basic & fabricated metal and other sub-industries, respectively. Total TFP in the manufacturing sector has grown at the annual rate of 0.052, although the rate of growth decreased continuously during the sample period. For the sub-industry estimates during the sample period, TFP grew fastest in the footwear sub-industry, with annual average growth rate of 11.8%, followed by the rubber & plastic products with a rate of 7.3%, and the food products & beverages with a rate of 5.8% per annum.

关键词： Total Factor Productivity Technical Efficiency Change Technological Progress Stochastic Frontier Approach Vietnamese Manufacturing Industry

SIMULATION MODEL OF TECHNOLOGICAL MINERAL DRESSING PROCESSES

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International Journal of Modeling, Simulation, and Scientific Computing 2012年第3期3卷 36-42页

作者： nguyen van CHI A.V.PETROV Department of Automated Systems Irkutsk State Technical University Lermontova 83 Irkutsk664074Russian Federation

The authors worked out a simulation model of technological mineral dressing processes,in which two simulations of technological mineral dressing processes methods are used:transformed structural graph method and method of separation *** first method makes it possible to simulate technological mineral dressing processes at the design stage in conditions of feedstock,equipment and control information *** second method is an effective instrument for operating plant simulation at the reengineering *** and economic efficiency evaluations of the mineral dressing plant are appended to the model.

关键词： Simulation mineral dressing structural graph separation characteristics reengineering efficiency

Antidiabetic and antioxidant activities of red seaweed Laurencia dendroidea

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Asian Pacific Journal of Tropical Biomedicine 2019年第12期9卷 501-509页

作者： The Han nguyen Thi Huyen nguyen van Minh nguyen Thi Lan Phuong nguyen Thi van Anh Tran Anh Duy Do Sang Moo Kim Faculty of Food Technology Nha Trang University02 Nguyen Dinh Chieu StreetNha Trang CityKhanh HoaVietnam Quality Control Department Institute of Vaccines and Medical BiologicalsNha Trang CityKhanh HoaVietnam Faculty of Pharmacy University of Medicine and Pharmacy of Ho Chi Minh City41 Dinh Tien Hoang StreetHo Chi Minh CityVietnam Research Department of Marine Conservation Research Institute for Marine Fisheries224 Le Lai StreetHai Phong CityVietnam Department of Marine Food Science and Technology Gangneung-Wonju National University7 Jukheon-gilGangneung 25457Republic of Korea

Objective:To investigate antidiabetic and antioxidant activities of the extract and fractions from Vietnamese red seaweed Laurencia ***:The seaweed Laurencia dendroidea was extracted by using microwave-assisted extraction method in 80%*** seaweed extract was then fractionated using different solvents(n-hexane,chloroform,ethyl acetate,butanol and water).These obtained fractions were evaluated forα-glucosidase inhibitory and antioxidant *** activities were tested using DPPH,nitric oxide radical scavenging and metal chelating *** enzyme inhibition mode was determined using Lineweaver-Burk *** acidic and thermal stabilities,the ethyl acetate fraction was treated at pH 2.0 and 100℃,*** residual inhibitory activity of the fraction was calculated based on the initial inhibitory *** in vivo antidiabetic activity,mice were divided into four groups,including normal control,diabetic control,diabetic mice treated with ethyl acetate fraction and diabetic mice treated with *** glucose level of treated mice during acute and prolonged treatments was *** evaluate the toxicity of the ethyl acetate fraction,the body weight changes and activities of liver function enzymes(aspartate transaminase,alanine transaminase and gammaglutamyl transferase)were carried ***:The extract of Laurencia dendroidea showed strongα-glucosidase inhibitory and DPPH radical scavenging *** concentrations affected bothα-glucosidase inhibitory and antioxidant activities.A 80%aqueous methanol was the suitable solvent for extraction of enzyme inhibitors and *** solvent fractions,ethyl acetate fraction had the highest inhibitory activities againstα-glucosidase with a mixed type of inhibition and the strongest antioxidant activities,and was stable under acidic and thermal *** ethyl acetate fraction treated diabetic mice significantly reduced blood glucose level compare

关键词： α-Glucosidase inhibitor Antidiabetic Antioxidant Red seaweeds Vietnam

Tungsten-based nanocatalysts with different structures for visible light responsive photocatalytic degradation of bisphenol A

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Journal of Environmental Sciences 2024年第5期139卷 569-588页

作者： Hai Bang Truong Thi Thu Loan Doan nguyen Tien Hoang nguyen van Tam Minh Kim nguyen Le Gia Trung Jin Seog Gwag nguyen Tien Tran Optical Materials Research Group Science and Technology Advanced InstituteVan Lang UniversityHo Chi Minh CityViet Nam Faculty of Applied Technology School of TechnologyVan Lang UniversityHo Chi Minh CityViet Nam The University of Da Nang University of Science and Technology54 Nguyen Luong BangDa NangViet Nam The University of Da Nang University of Science and Education459 Ton Duc Thang St.Lien ChieuDa Nang 550000Viet Nam Institute of Veterinary Science and Technology 31ha zoneTrau QuyGia LamHa Noi 12400Viet Nam Department of Physics Yeungnam UniversityGyeongsanGyeongbuk 38541Republic of Korea Center for Advanced Chemistry Institute of Research and DevelopmentDuy Tan University03 Quang TrungDa Nang 550000Viet Nam Faculty of Natural Sciences Duy Tan University03 Quang TrungDa Nang 550000Viet Nam

Environmental pollution,such as water contamination,is a critical issue that must be absolutely ***,three different morphologies of tungsten-based photocatalysts(WO_(3)nanorods,WO_(3)/WS_(2)nanobricks,WO_(3)/WS_(2)nanorods)are made using a simple hydrothermal method by changing the solvents(H_(2)O,DMF,aqueous HCl solution).The as-prepared nanocatalysts have excellent thermal stability,large porosity,and high *** results show all materials have good photocatalytic activity in aqueous media,with WO_(3)/WS_(2)nanorods(NRs)having the best activity in the photodegradation of bisphenol A(BPA)under visible-light *** may originate from increased migration of charge carriers and effective prevention of electron–hole recombination in WO_(3)/WS_(2)NRs,whereby this photocatalyst is able to generate more reactive·OH and·O_(2)^(–)species,leading to greater photocatalytic *** 99.6% of BPA is photodegraded within 60 min when using 1.5 g/L WO_(3)/WS_(2)NRs and 5.0 mg/L BPA at pH ***,the optimal conditions(pH,catalyst dosage,initial BPA concentration)for WO_(3)/WS_(2)NRs are also elaborately *** rod-like heterostructures are expressed as potential catalysts with excellent photostability,efficient reusability,and highly active effectivity in different types of *** particular,the removal efficiency of BPA by WO_(3)/WS_(2)NRs reduces by only 1.5% after five recycling runs and even reaches 89.1%in contaminated lake *** study provides promising insights for the nearly complete removal of BPA from wastewater or different water resources,which is advantageous to various applications in environmental remediation.

关键词： Photodegradation Bisphenol A Tungsten-based nanocatalyst Structure Nanorod

Teachers＇ Concerns and Solutions Towards The Implementation of Digital Storytelling in Teaching English in ESL Classroom in Asian Countries

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Journalism and Mass Communication 2015年第9期5卷 454-462页

作者： khanh nguyen Bui Ho Chi Minh City University of Education Ho Chi Minh City Vietnam The University of Georgia Georgia USA

We are living in the era of Information Technology where students have a lot exposure to the state-of-the-art devices and softwares. The remarkable revolutions in interactivity and multimedia materials together with countless emerging technologies have also enabled the conception of digital storytelling. However, it has not been widely used in many developing countries such as Vietnam. Therefore, the purpose of this paper is to conduct an investigation into the history of digital storytelling, the necessary facilities and how it is being used educationally in the classroom so that teachers in developing countries can widely apply digital storytelling in teaching. This paper also raises students＇ awareness towards using technology in their study, which will make an important breakthrough in teaching and learning English in Vietnam.

关键词： digital storytelling educationally-used technology Asian countries

A New Approach for Ranking Efficient Units in Data Envelopment Analysis and Application to a Sample of Vietnamese Agricultural Bank Branches

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American Journal of Operations Research 2012年第1期2卷 126-136页

作者： nguyen Khac Minh Pham van khanh Pham Anh Tuan Air Defence-Air Force Academy Hanoi Vietnam Military Technical Academy Hanoi Vietnam Water Resources University Hanoi Vietnam

This paper proposes a new approach for ranking efficiency units in data envelopment analysis as a modification of the super-efficiency models developed by Tone [1]. The new approach based on slacks-based measure of efficiency (SBM) for dealing with objective function used to classify all of the decision-making units allows the ranking of all inefficient DMUs and overcomes the disadvantages of infeasibility. This method also is applied to rank super-efficient scores for the sample of 145 agricultural bank branches in Viet Nam during 2007-2010. We then compare the estimated results from the new SCI model and the exsisting SBM model by using some statistical tests.

关键词： Data Envelopment Analysis (DEA) Slacks-Based Measure of Efficiency (SBM) SCI Super-Efficient

Determination of groundwater solute transport parameters in finite element modelling using tracer injection and withdrawal testing data

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Journal of Groundwater Science and Engineering 2021年第4期9卷 292-303页

作者： van Hoang nguyen Institute of Geological Sciences-Vietnam Academy of Science and Technology HanoiVietnam

The groundwater tracer injection and withdrawal tests are often carried out for the determination of aquifer solute transport ***,the parameter analyses encounter a great difficulty due to the radial flow nature and the variability of the temporal boundary *** adaptive methodology for the determination of groundwater solute transport parameters using tracer injection and withdrawal test data had been developed and illustrated through an actual *** methodology includes the treatment of the tracer boundary condition at the tracer injection well,the normalization of tracer concentration,the groundwater solute transport finite element modelling and the method of least squares to optimize the *** application of this methodology was carried out in a field test in the South of Hanoi *** tested aquifer is Pleistocene aquifer,which is a main aquifer and has been providing domestic water supply to the city since the French *** porosity of 0.31,longitudinal dispersivity of 2.2 m,and hydrodynamic dispersion coefficients from D=220 m^(2)/d right outside the pumping well screen to D=15.8 m^(2)/d right outside the tracer injection well screen have been obtained for the aquifer at the test *** minimal sum of squares of the differences between the observed and model normalized tracer concentration is 0.00119,which is corresponding to the average absolute difference between observed and model normalized concentrations of 0.0355(while 1 is the worst and 0 is the best fit).

关键词： Groundwater solute transport Tracer injection Effective porosity Longitudinal dispersivity Flow distortion coefficient Normalized concentration

On the Laws of Large Numbers for Double Arrays of Independent Random Elements in Banach Spaces

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Acta Mathematica Sinica,English Series 2014年第8期30卷 1353-1364页

作者： Andrew ROSALSKY Le van THANH nguyen Thi THUY Department of Statistics University of FloridaGainesville Department of Mathematics Vinh University

For a double array of independent random elements {Vmn,m ≥ 1,n ≥ 1} in a real separable Banach space,conditions are provided under which the weak and strong laws of large numbers for the double sums mi=1 nj=1Vij,m ≥ 1,n ≥ 1 are *** the identically distributed and the nonidentically distributed cases are *** the main theorems,no assumptions are made concerning the geometry of the underlying Banach *** theorems are applied to obtain Kolmogorov,Brunk–Chung,and Marcinkiewicz–Zygmund type strong laws of large numbers for double sums in Rademacher type p（1 ≤ p ≤ 2） Banach spaces.

关键词： Real separable Banach space double array of independent random elements strong and weak laws of large numbers almost sure convergence convergence in probability Rademacher type p Banach space

Sulphur vacancy defects engineered metal sulfides for amended photo(electro)catalytic water splitting: A review

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Journal of Materials Science & Technology 2023年第21期152卷 50-64页

作者： Kusum Sharma Abhinandan Kumar Tansir Ahamad Quyet van Le Pankaj Raizada Archana Singh Lan Huong nguyen Sourbh Thakur van-Huy nguyen Pardeep Singh School of Advanced Chemical Sciences Shoolini UniversitySolanHimachal Pradesh 173212India Department of Chemistry College of ScienceKing Saud UniversitySaudi Arabia Department of Materials Science and Engineering Korea University145AnamroSeongbuk-guSeoul 02841Republic of Korea Advanced Materials and Processes Research Institute Hoshangabad RoadBhopalMP 462026India Faculty of Biology and Environment Ho Chi Minh City University of Food Industry(HUFI)140 Le Trong Tan StreetTay Thanh WardTan Phu DistrictHo Chi Minh CityVietnam Department of Organic Chemistry Bioorganic Chemistry and BiotechnologySilesian University of TechnologyB.Krzywoustego 444-100 GliwicePoland Faculty of Allied Health Sciences Chettinad Hospital and Research InstituteChettinad Academy of Research and EducationKelambakkam-603103Tamil NaduIndia

Vacancy engineering in metal sulfides has garnered enormous attention from researchers because of their outstanding ability to modulate the optical and physiochemical properties of ***,in the case of sulfides,the catalytic activity is drastically hindered by the quick reassembly of excitons and the photocorrosion *** designing and generating S-vacancies in metal sulfides has emerged as a potential strategy for attaining adequate water splitting to generate H_(2) and O_(2) because of the simulta-neous improvement in the optoelectronic ***,developing efficient catalysts that manifest optimal photo(electro)catalytic performance for large-scale applicability remains ***,it is of utmost interest to explore the insightful features of creating S-vacancy and study their impact on catalytic *** review article aims to comprehensively highlight the roles of S-vacancy in sulfides for amended overall water-splitting *** photocatalytic features of S-vacancies modulated metal sulfides are deliberated,followed by various advanced synthetic and characterization techniques for effectual generation and identification of vacancy *** specific aspects of S-vacancies in refin-ing the optical absorption range charge carrier dynamics,and photoinduced surface chemical reactions are critically examined for overall water splitting ***,the vouchsafing outlooks and op-portunities confronting the defect-engineered(S-vacancy)metal sulfides-based photocatalysts have been summarized.

关键词： S-vacancy Photo(electro)catalysis Metal sulfides Water splitting Engineering Identification of S-vacancies