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Development of a PARCS/Serpent model for neutronics analysis of the Dalat nuclear research reactor

Nuclear Science and Techniques 2021年第2期32卷 32-44页

作者： Viet-Phu tran Kien-Cuong Nguyen Donny Hartanto hoai-nam tran Vinh Thanh tran Van-Khanh Hoang Pham Nhu Viet Ha Institute for Nuclear Science and Technology(INST) Vietnam Atomic Energy Institute(VINATOM)179 Hoang Quoc Viet str.Cau Giay DistrictHanoi 100000Vietnam Nuclear Research Institute(NRI) Vietnam Atomic Energy Institute(VINATOM)01 Nguyen Tu LucDalatLamdong 670000Vietnam Department of Mechanical and Nuclear Engineering University of SharjahPO.BOX 27272SharjahUnited Arab Emirates Institute of Fundamental and Applied Sciences Duy Tan UniversityHo Chi Minh city 700000Vietnam Faculty of Natural Science Duy Tan UniversityDanang 550000Vietnam Nuclear Safety Division Technical Support Center for Radiation and Nuclear Safety and Emergency ResponseVietnam Agency for Radiation and Nuclear Safety(VARANS)113 Tran Duy Hung str.Cau Giay DistrictHanoi 100000Vietnam

Cross-sectional homogenization for full-core calculations of small and complex reactor configurations,such as research reactors,has been recently recognized as an interesting and challenging *** paper presents the development of a PARCS/Serpent model for the neutronics analysis of a research reactor type TRIGA Mark-II loaded with Russian VVR-M2 fuel(known as the Dalat Nuclear Research Reactor or DNRR).The full-scale DNRR model and a supercell model for a shim/safety rod and its surrounding fuel bundles with the Monte Carlo code Serpent 2 were proposed to generate homogenized fewgroup cross sections for full-core diffusion calculations with *** full-scale DNRR model with Serpent 2 was also utilized as a reference to verify the PARCS/Serpent *** of the effective neutron multiplication factors,radial and axial core power distributions,and control rod worths showed a generally good agreement between PARCS and Serpent *** addition,the discrepancies between the PARCS and Serpent 2 results are also ***,the results indicate the applicability of the PARCS/Serpent model for further steady state and transient analyses of the DNRR.

关键词： PARCS Serpent 2 Group constant DNRR

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

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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

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

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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

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Determination of fuel burnup distribution of a research reactor based on measurements at subcritical conditions

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Nuclear Science and Techniques 2018年第12期29卷 30-38页

作者： Quang Binh Do hoai-nam tran Quang Huy Ngo Giang T. T. Phan Ho Chi Minh City University of Technology and Education 1 Vo Van Ngan Thu Duc HCMC Vietnam Institute of Fundamental and Applied Sciences Duy Tan University Ho Chi Minh city Vietnam

This paper presents the determination of the fuel burnup distribution of the Dalat nuclear research reactor(DNRR) using a method of measurements at subcritical conditions. The method is based on the assumption of linear dependence of the reactivity on the burnup of fuel bundles and the measurements at subcritical *** measurements were taken for seven selected fuel bundles in two different measuring sequences. The measured burnup values have also been compared with the calculations for verifying the method and the measurement procedure. The results obtained with the three detectors have a good agreement with each other with a discrepancy less than 1.0%. The errors of the measured burnup values are within 6%. Comparison between the calculated and measured burnup values shows that the discrepancy of the C/E ratio is within 9% compared to unity. The results indicate that the method of measurements at subcritical conditions could be well applied to determine the relative burnup distribution of the DNRR.

关键词：研究反应堆燃料分发测量过程验证方法方法论价值计算

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Calibration of a neutron dose rate meter in various neutron standard fields

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Nuclear Science and Techniques 2020年第6期31卷 75-82页

作者： Tuan Khai Nguyen hoai-nam tran Quynh Ngoc Nguyen Thi My Linh Dang Van Loat Bui Thiansin Liamsuwan Ngoc-Thiem Le Vietnam Agency for Radiation and Nuclear Safety 113 Tran Duy HungHanoi 100000Vietnam Institute of Fundamental and Applied Sciences Duy Tan UniversityHo Chi Minh 700000Vietnam Faculty of Natural Sciences Duy Tan University3 Quang TrungDa Nang 550000Vietnam Institute for Nuclear Science and Technology VINATOM179 Hoang Quoc VietHanoi 100000Vietnam Faculty of Physics VNU University of Science334 Nguyen TraiHanoi 100000Vietnam Nuclear Research and Development Division Thailand Institute of Nuclear TechnologyOngkharakNakorn NayokThailand 7 Faculty of Medicine and Public HealthHRH Princess Chulabhorn College of Medical ScienceChulabhorn Royal AcademyBangkokThailand

This paper presents the calibration of a neutron dose rate meter and the evaluation of its calibration factors(CFs)in several neutron standard fields(i.e.,two standard fields with bare sources of252Cf and241Am-Be,and five simulated workplace fields with241Am-Be moderated sources).The calibration in standard fields with bare sources was conducted by following the recommendations of the ISO 8529 *** measured total neutron ambient dose equivalent rates,denoted as H*(10)tot,were analyzed to obtain direct components,denoted as H*(10)dir,using a reduced fitting *** CF was then calculated as the ratio between the conventional true value of the neutron ambient dose equivalent rate in a free field,denoted as H*(10)FF,and the value of H*(10)*** contrast,in the simulated workplace neutron fields,the calibration of the neutron dose rate meter was conducted by following the ISO 12789 *** CF was calculated as the ratio between the values of H*(10)totmeasured by a standard instrument(i.e.,Bonner sphere spectrometer)and the neutron dose rate *** CF values were obtained in the range of 0.88–*** standard uncertainties(k=1)of the CFs were determined to be in the range of approximately 6.6–13.1%.

关键词： Neutron standard fields Neutron dose rate meter Calibration factor 252Cf source 241AmBe source

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An isogeometric analysis approach for dynamic response of doubly-curved magneto electro elastic composite shallow shell subjected to blast loading

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Defence Technology（防务技术） 2024年第11期41卷 159-180页

作者： Pham Hoang Tu tran Van Ke Vu Khac Trai Le hoai Faculty of Automotive Engineering School of TechnologyVan Lang UniversityHo Chi Minh City 700000Viet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoi 100000Viet Nam Faculty of Engineering and Technology Nguyen Tat Thanh UniversityHo Chi Minh City 700000Viet Nam HUTECH Institute of Engineering HUTECH UniversityHo Chi Minh City 700000Viet Nam

For the first time, the isogeometric analysis(IGA) approach is used to model and analyze free and forced vibrations of doubly-curved magneto-electro-elastic(MEE) composite shallow shell resting on the visco-Pasternak foundation in a hygro-temperature environment. The doubly-curved MEE shallow shell types include spherical shallow shell, cylindrical shallow shell, saddle shallow shell, and elliptical shallow shell subjected to blast load are investigated. The Maxwell equation and electromagnetic boundary conditions are used to determine the vary of the electric and magnetic potentials. The MEE shallow shell's equations of motion are derived from Hamilton's principle and refined higher-order shear theory. Then, the IGA method is used to derive the laws of natural frequencies and dynamic responses of the shell under various boundary conditions. The accuracy of the model and method is verified through reliable numerical comparisons. Aside from this, the impact of the input parameters on the free and forced vibration of the doubly-curved MEE shallow shell is examined in detail. These results may be useful in the design and manufacture of military structures such as warships, fighter aircraft, drones and missiles.

关键词： IGA approach Free and forced vibration Doubly-curved MEE shallow shell Blast load

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The Continuous Knapsack Problem with Capacities

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Journal of the Operations Research Society of China 2021年第3期9卷 713-721页

作者： Huynh Duc Quoc Nguyen Chi Tam tran hoai Ngoc Nhan Department of Mathematics College of Natural ScienceCan Tho UniversityCan Tho City 900900Vietnam Faculty of Basic Sciences Vinh Long University of Technology EducationVinh Long 940000Vietnam

We address a variant of the continuous knapsack problem,where capacities regarding costs of items are given into *** prove that the problem is NP-complete although the classical continuous knapsack problem is solvable in linear *** the case that there exists exactly one capacity for all items,we solve the corresponding problem in O(n log n)time,where n is the number of items.

关键词： Knapsack problem Complexity Capacity Polynomially solvabl

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Novel Soft ComputingModel for Predicting Blast-Induced Ground Vibration in Open-Pit Mines Based on the Bagging and Sibling of Extra Trees Models

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Computer Modeling in Engineering & Sciences 2023年第3期134卷 2227-2246页

作者： Quang-Hieu tran Hoang Nguyen Xuan-nam Bui Department of Surface Mining Mining FacultyHanoi University of Mining and GeologyHanoi100000Vietnam Innovations for Sustainable and Responsible Mining(ISRM)Research Group Hanoi University of Mining and GeologyHanoi100000Vietnam

This study considered and predicted blast-induced ground vibration(PPV)in open-pit mines using bagging and sibling techniques under the rigorous combination of machine learning ***,four machine learning algorithms,including support vector regression(SVR),extra trees(ExTree),K-nearest neighbors(KNN),and decision tree regression(DTR),were used as the base models for the purposes of combination and PPV initial *** bagging regressor(BA)was then applied to combine these base models with the efforts of variance reduction,overfitting elimination,and generating more robust predictive models,abbreviated as BA-ExTree,BAKNN,BA-SVR,and *** is emphasized that the ExTree model has not been considered for predicting blastinduced ground vibration before,and the bagging of ExTree is an innovation aiming to improve the accuracy of the inherently ExTree model,as *** addition,two empirical models(i.e.,USBM and Ambraseys)were also treated and compared with the bagging models to gain a comprehensive *** this aim,we collected 300 blasting events with different parameters at the Sin Quyen copper mine(Vietnam),and the produced PPV values were also *** were then compiled as the dataset to develop the PPV predictive *** results revealed that the bagging models provided better performance than the empirical models,except for the BA-DTR *** those,the BA-ExTree is the best model with the highest accuracy(i.e.,88.8%).Whereas,the empirical models only provided the accuracy from 73.6%–76%.The details of comparisons and assessments were also presented in this study.

关键词： Mine blasting blast-induced ground vibration environmentally friendly blasting peak particle velocity bagging extra trees

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

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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

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Performance evaluation of a two-way relay network with energy harvesting^and hardware noises

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Digital Communications and Networks 2021年第1期7卷 45-54页

作者： Nguyen Tien Tung Pham Minh nam Phu tran Tin Faculty of Electronics Technology Industrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Wireless Communcations Research Group Faculy of Electrical and Electronics EngineeringTon Duc Thang UniversityHo Chi Minh CityVietnam

In this paper,we propose a Two-Way Cognitive Relay Network(TWCRN)where the secondary users operate on an underlay mode to access the licensed *** the proposed protocols,two secondary sources transmit their data to a relay in the first time slot,and then the relay would forward the received information to both sources in the remaining ***,the relay is self-powered by harvesting energy from ambient Radio Frequency(RF)signals,using the Time Switching(TS)and the Power Switching(PS)*** paper concentrates on eval-uating the performance of the secondary networks under the impact of hardware impairments and co-channel interference from the primary *** particular,based on the secondary transmitters'constraint power,we derive the closed-form expressions of the outage probability and the throughput over Rayleigh fading channels in two cases:TS and *** also investigate the energy efficiency issue and the locally optimal position of the relay to maximize the system throughput,which provides much information to install the relay ***,our derivations are verified by Monte Carlo simulation.

关键词： Energy harvesting Two-way relay Energy efficiency Hardware impairments Cognitive network

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