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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 t.an 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 t.an 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

New Results on System of Generalized Quasi-Ky Fan Inequalities with Set-Valued Mappings in topological Semilattice Spaces

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Journal of Systems Science & Complexity 2016年第6期29卷 1585-1595页

作者： NGUYEN the Vinh PHAM thi hoai Department of Mathematics University of Transport and Communications School of Applied Mathematics and Informatics University of Science and Technology

Under new assumptions,this paper obtains some extended versions of Ky Fan type inequality for a family of C-continuous set-valued mappings in the setting of topological *** obtained results are new and different from the corresponding known results in the *** special cases of the main result are also *** examples are given to illustrate the results.

关键词： C△-quasiconvex (quasiconcave) Fan-Browder fixed point theorem set-valued Ky Faninequality topological semilattice upper (lower) C-continuous.

HⅠ emission from the red giant Y CVn with the VLA and FASt

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Research in Astronomy and Astrophysics 2017年第7期17卷 39-46页

作者： Do t.hoai Pham t.Nhung Lynn D.Matthews Eric Grard thibaut Le Bertre Department of Astrophysics Vietnam National Satellite CenterVAST LERMA CNRSObservatoire de Paris/PSLSorbonne Universite's Department of Astrophysics Vietnam National Satellite Center MIt Haystack Observatory GEPI CNRSObservatoire de Paris/PSL

Imaging studies with the Very Large Array（VLA） have revealed H I emission associated with the extended circumstellar shells of red giants. We analyze the spectral map obtained on Y CVn, a J-type carbon star on the Asymptotic Giant Branch. the H I line profiles can be interpreted with a model of a detached shell resulting from the interaction of a stellar outflow with the local interstellar *** reproduce the spectral map by introducing a distortion along a direction corresponding to the star＇s motion in space. We then use this fitting to simulate observations expected from the Five-hundred-meter Aperture Spherical radio telescope（FASt）, and discuss its potential for improving our description of the outer regions of circumstellar shells.

关键词： stars AGB and post-AGB-- stars carbon - stars individual Y CVn - radio lines stars

EP Aquarii:A New Picture of the Circumstellar Envelope

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Research in Astronomy and Astrophysics 2024年第3期24卷 83-105页

作者： Pham t.Nhung Do t.hoai Pierre Darriulat Pham t.an-Anh Pham N.Diep Nguyen B.Ngoc t.an t.thai Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18Hoang Quoc VietNghia DoCau GiayHa Noivietnam

New analyses of earlier ALMA observations of oxygen-rich AGB star EP Aquarii are presented,which complete a previously published analysis and offer a different interpretation of the morpho-kinematics of the circumstellar *** birth of the equatorial density enhancement(EDE)is shown to occur very close to the star where evidence for rotation has been *** to the star and where outflows have been observed:their interaction with the gas of the nascent EDE is seen to play an important role in the development of the wind and the evolution of its radial velocity from 8 to 10 km s^(-1) on the polar symmetry axis to~2 km s^(-1) at the *** implies complex morpho-kinematics:making reliable interpretations with reasonable confidence is *** particular,it questions an earlier interpretation implying the presence of a white dwarf companion orbiting the star at.an angular distance of -0″4 from its *** proposes instead an interpretation in terms of a standard mass ejection associated with a shock wave leaving a void of emission in its *** Doppler velocity wings are seen to consist of two components,the upper velocity end of the global wind,reaching above±12 km s^(-1),and an effective line broadening,confined within 200 mas from the center of the star,reaching above±20 km s^(-1) and interpreted as caused by the pattern of shock waves resulting from the interaction between stellar pulsation and convective cell partition.

关键词： stars AGB and post-AGB-(stars) circumstellar matter-radio lines stars

Suzuki Reaction of Aryl Bromides Using a Phosphine-Free Magnetic Nanoparticle-Supported Palladium Catalyst

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催化学报 2011年第11期32卷 1667-1676页

作者： Nghia t. BUI trung B. DANG Ha V. LE nam t. S. PHAN Department of Chemical Engineering HCMC University of Technology VNU-HCM 268 Ly Thuong Kiet Distriet 10 Ho Chi Minh City Viet Nam

A palladium catalyst immobilized on superparaganetic nanoparticles was prepared with a palladium loading of 0.30 mmol/g. the catalyst was characterized using X-ray diffraction, scanning electron microscopy, t.ansmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, Fourier t.ansform infrared, atomic absorption spectrophotometry, and nitrogen adsorption. the immobilized palladium catalyst was an efficient catalyst without added phosphine ligands for the Suzuki cross-coupling reaction of several aryl bromides with phenylboronic acid. the recovery of catalyst was simply by magnetic decantation in the presence of a magnet. the immobilized palladium catalyst can be reused many times without significant degradation in catalytic activity. No leaching of active palladium species into the reaction solution was detected.

关键词： superparamagnetic nanoparticle Suzuki reaction palladium aryl bromide

Robust exponential stability and stabilization of linear uncertain polytopic time-delay systems

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控制理论与应用（英文版） 2008年第2期6卷 163-170页

作者： nam PHAN t. Phat VU N. Department of Mathematics Quynhon UniversityQuynhonBinhdinhVietnam Institute of Mathematics 18 Hoang Quoc Viet RoadHanoiVietnam

this paper proposes new sufficient conditions for the exponential stability and *** linear uncertain polytopic time-delay systems. the conditions for exponential stability are expressed in terms of Kharitonov-type linear matrix inequalities （LMIs） and we develop control design methods based on LMIs for solving stabilization problem. Our method consists of a combination of the LMI approach and the use of parameter-dependent Lyapunov functionals, which allows to compute simultaneously the two bounds that characterize the exponetial stability rate of the solution. Numerical examples illustrating the conditions are given.

关键词： Polytopic time-delay system Exponential stability Stabilization Parameter-dependent Lyapunov function Linear matrix inequalities

A New Inertial Self-adaptive Gradient Algorithm for the Split Feasibility Problem and an Application to the Sparse Recovery Problem

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Acta Mathematica Sinica,English Series 2023年第12期39卷 2489-2506页

作者： Nguyen the VINH Pham thi hoai Le Anh DUNG Yeol Je CHO Department of Mathematical Analysis University of Transport and Communications3 Cau Giay StreetHanoiVietnam Department of Applied Mathematics School of Applied Mathematics and InformaticsHano University of Science and Technology1 Dai Co Viet RoadHanoiVietnam Department of Mathematics and Informatics Hanoi University of Education136 Xuan ThuyCau GiayHanoiVietnam Department of Mathematics Education Gyeongsang National UniversityJinju52828Republicof Korea

In this paper,by combining the inertial technique and the gradient descent method with Polyak's stepsizes,we propose a novel inertial self-adaptive gradient algorithm to solve the split feasi-bility problem in Hilbert spaces and prove some strong and weak convergence theorems of our method under standard *** examine the performance of our method on the sparse recovery prob-lem beside an example in an infinite dimensional Hilbert space with synthetic data and give some numerical results to show the potential applicability of the proposed method and comparisons with related methods emphasize it further.

关键词： Split feasibility problem CQ algorithm Hilbert space sparse recovery problem

t.ansport mechanism in chemically reactive hybrid nanofluid flow containing gyrotactic micro-organisms over a curved oscillatory surface

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 177-192页

作者： M.NAVEED M.IMRAN t.ASGHAR Z.ABBAS Department of Mathematics Division of Science and TechnologyUniversity of Education Department of Mathematics The Islamia University of Bahawalpur

this paper examines the t.ansport.analysis, including both heat t.ansfer and mass t.ansfer, in hybrid nanofluid flow containing gyrotactic microorganisms towards a curved oscillatory surface. the influence of magnetic fields is also inspected in terms of their physical characteristics. to depict the phenomena of t.ansport, modified versions of both Fick's and Fourier's laws are used. Additionally, the characteristics of both heterogeneous and homogeneous chemical reactions are also incorporated. Utilizing a curvilinear coordinate system, the flow problem is formulated as partial differential equations(PDEs)for momentum, concentration, microorganism field, and energy. An analytical solution to the obtained flow equations is achieved utilizing the homotopy analysis method(HAM).the effects of significant flow parameters on the pressure and microorganism fields, velocity, oscillation velocity, concentration, and temperature distributions are shown via graphs. Furthermore, the variations in skin friction, mass t.ansfer rate, heat t.ansfer rate, and local motile number due to different involved parameters are presented in tables and are analyzed in detail. Graphical results indicate that the curves of velocity and temperature fields are enhanced as the values of the solid volume fraction variables *** is also verified that the concentration rate field decreases as the values of the homogeneous reaction strength parameter and the radius of curvature parameter increase, and it increases with the Schmidt number and the heterogeneous reaction strength *** outcomes show a favorable response of the motile number to advanced values of the Peclet number, the Schmidt number, the microorganism difference parameter, and the bio-convective Lewis number.

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Liquid-liquid extraction and separation of total rare earth(RE) metals from polymetallic manganese nodule leaching solution

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Journal of Rare Earths 2015年第2期33卷 207-213页

作者： P.K.Parhi K.H.Park C.W.nam J.t.Park Mineral Resources Research Division Korea Institute of Geoscience & Mineral Resources (KIGAM)Daejeon 305-350 Republic of Korea School of Applied Science and Center of Industrial technology KIIT UniversityBhubaneswar 751024 Odisha India

the study on the solvent extraction for quantitative and selective separation of total rare earth metals from the polymetallic nodule leach liquor was investigated. the typical leach liquor bearing 0. 094 g/L total rare earth, 0. 23 g/L Mn, 0.697 g/L Cu, 0.2 g/L Fe, 0.01 g/L Co and 0.735 g/L Ni was subjected to the removal iron content by precipitation method using Ca（OH）2 at pH 3.95, prior to solvent extraction of rare earth metals. three different organo-phosphoric acid reagents（D2EHPA, PC88 A, Cyanex 272） were used to ascertain their performances and selectivity towards the loading of rare earth metals in presence of other base metals. Based on the results of eq. pH effect, the performances of above three extractants followed the order as： D2EHPA〉PC88A〉Cyanex 272. to ensure the absence of extraction of base metals（Cu, Co, Ni）, the eq. pH of the solution was optimized at the level of 2.21, though higher rare earth metal extraction efficiency was observed at higher eq. pH with either of the extractants. the complete process flow diagram for substantial recovery of total rare earth was developed using D2 EHPA. Extraction isotherm plot was constructed at A：O=12：1, 3-stages and pHe=2.21, using 0.8 mol/L D2 EHPA and the predicted condition of this study was further confirmed by 6-Cycles Counter Current Simulation（CCS） study. the stripping of total rare earth from loaded organic phase（LO） was conducted using HCl solution. Mc-Cabe thiele diagram study carried out at A：O=1：5 using 4 mol/L HCl showed that three theoretical stages were needed for quantitative stripping of total rare earth. the subsequent stripped solution resulted thus led to contain total rare earth of 5.6 g/L indicating a very high enrichment of total metals by solvent extraction（SX） process.

关键词： total rare earth (RE) metals SX D2EHPA HCl deep sea nodule