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Examination of n-T_(9) conditions required by N=50,82,126 waiting points in r-process

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Communications in Theoretical Physics 2021年第10期73卷 147-157页

作者： nguyen duy Ly nguyen Ngoc duy nguyen Kim Uyen Vinh N T Pham Faculty of Fundamental Sciences Vanlang UniversityHo Chi Minh City 700000Vietnam Department of Physics Sungkyunkwan UniversitySuwon 16419Republic of Korea Department of Physics Ho Chi Minh City University of EducationHo Chi Minh City 700000Vietnam

We examined the conditions of neutron density(n) and temperature(T9) required for the N = 50, 82,and 126 isotopes to be waiting points(WP) in the r-process. The nuclear mass based on experimental data presented in the AME2020 database(AME and AME ± Δ) and that predicted using FRDM,WS4, DZ10, and KTUY models were employed in our estimations. We found that the conditions required by the N = 50 WP significantly overlap with those required by the N = 82 ones, except for the WS4 model. In addition, the upper(or lower) bounds of the n-T9 conditions based on the models are different from each other due to the deviations in the two-neutron separation *** standard deviations in the nuclear mass of 108 isotopes in the three N = 50, 82, and 126 groups are about rms = 0.192 and 0.434 Me V for the pairs of KTUY-AME and WS4-KTUY models,respectively. We found that these mass uncertainties result in a large discrepancy in the nn-T_(9) conditions, leading to significant differences in the conditions for simultaneously appearing all the three peaks in the r-process abundance. The newly updated FRDM and WS4 calculations can give the overall conditions for the appearance of all the peaks but vice versa for their old versions in a previous study. The change in the final r-process isotopic abundance due to the mass uncertainty is from a few factors to three orders of magnitude. Therefore, accurate nuclear masses of the r-process key nuclei, especially for 76 Fe,81Cu,127Rh,132Cd,192Dy, and 197Tm, are highly recommended to be measured in radioactive-ion beam facilities for a better understanding of the r-process evolution.

关键词： neutron capture r-process nuclear mass isotopic abundance precise mass measurement

One-loop contributions for h→?■γ and e-e+→hγ in the U（1）B-L extension of the standard model

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Chinese Physics C 2024年第5期 27-53页

作者： Tran Dzung Tri Thanh Huy nguyen Khiem Hong Phan Institute of Fundamental and Applied Sciences Duy Tan University Faculty of Natural Sciences Duy Tan University VNUHCM-University of Science

We present one-loop contributions for h→?■γ with l=ve,μ,τ,e,μ and e-e+→ hγ in the U（1）B-Lextension of the standard *** the phenomenological results,the signal strengths for h→?■γ at the Large Hadron Collider and for e-e+→hγ at future lepton colliders are analyzed in the physical parameter space for both the vector and chiral B-L *** found that the contributions from the neutral gauge boson Z' to the signal strengths are rather ***,the effects will be difficult to probe at future ***,the impacts of charged Higgs and CP-odd Higgs in the chiral B-L model on the signal strengths are significant and can be measured with the help of the initial polarization beams at future lepton colliders.

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

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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

Finsler Trudinger-Moser inequalities on R^(2)

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Science China Mathematics 2022年第9期65卷 1803-1826页

作者： nguyen Tuan duy Le Long Phi Faculty of Economics and Law University of Finance-MarketingHCM City ***Vietnam Institute of Research and Development Duy Tan UniversityDa Nang 550000Vietnam

The first aim of this article is to study the sharp singular(two-weight)Trudinger-Moser inequalities with Finsler norms on R^(2).The second goal is to propose a different approach to study a vanishing-concentration-compactness principle for the Trudinger-Moser inequalities and use this to investigate the existence and the nonexistence of the maximizers for the Trudinger-Moser inequalities in the subcritical ***,by applying our Finsler Trudinger-Moser inequalities to suitable Finsler norms,we derive the sharp affine Trudinger-Moser inequalities which are essentially stronger than the Trudinger-Moser inequalities with standard energy of the gradient.

关键词： Trudinger-Moser inequality Finsler norm sharp constants extremal functions affine energy

Determination of Helmert transformation parameters for continuous GNSS networks:a case study of the Géoazur GNSS network

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Geo-Spatial Information Science 2023年第1期26卷 125-138页

作者： dinh Trong Tran Jean-Mathieu Nocquet Ngoc Dung Luong dinh Huy nguyen Department of Geodesy and Geomatics Engineering Hanoi University of Civil EngineeringHanoiVietnam UniversitéCôte d’Azur CNRSObservatoire de la Côte d’AzurIRDValbonneFrance

In this paper,we propose an approach to determine seven parameters of the Helmert transfor-mation by transforming the coordinates of a continuous GNSS network from the World Geodetic System 1984(WGS84)to the International Terrestrial Reference *** includes(1)convert-ing the coordinates of common points from the global coordinate system to the local coordinate system,(2)identifying and eliminating outliers by the Dikin estimator,and(3)estimating seven parameters of the Helmert transformation by least squares(LS)estimation with the“clean”data(*** removed).Herein,the local coordinate system provides a platform to separate points’horizontal and vertical ***,the Dikin estimator identifies and eliminates outliers in the horizontal or vertical component *** is significant because common points in a continuous GNSS network may contain *** proposed approach is tested with the Géoazur GNSS network with the results showing that the Dikin estimator detects outliers at 6 out of 18 common points,among which three points are found with outliers in the vertical compo-nent ***,instead of eliminating all coordinate components of these six common points,we only eliminate all coordinate components of three common points and only the vertical component of another three common ***,the classical LS estimation is applied to“clean”data to estimate seven parameters of the Helmert transformation with a significant accuracy *** Dikin estimator’s results are compared to those of other robust estimators of Huber and Theil-Sen,which shows that the Dikin estimator performs ***,the weighted total least-squares estimation is implemented to assess the accuracy of the LS estimation with the same *** inter-comparison of the seven estimated parameters and their standard deviations shows a small difference at a few per million levels(E-6).

关键词： Continuous GNSS tectonic geodesy Dikin estimation Helmert transformation

High Temperature Corrosion of Fe-C-S Cast Irons in Oxidizing and Sulfidizing Atmospheres

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Journal of Materials Science & Technology 2008年第3期24卷 327-329页

作者： Thuan-dinh nguyen Dong-Bok LEE School of Advanced Materials Science and Engineering Sungkyunkwan University

The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Fe0.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.

关键词： Cast iron Oxidation Sulfidation

Thermal Performance Prediction in the Air Gap of a Rotor-Stator Configuration: Effects of Numerical Models

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Journal of Thermal Science 2020年第1期29卷 206-218页

作者： DANG dinh-Dong PHAM Xuan-Tan nguyen Chi-Cong Department of Mechanical Engineering École de technologie supérieureMontrealQCCanada Hydro-Québec’s research institute VarennesQCCanada

This study is dedicated to a numerical investigation of convective heat transfer on the rotor surfaces of a rotor-stator configuration that is typically found in large *** computational fluid dynamics calculations with two turbulence modelling approaches are used to predict the flow structure and heat transfer in the air gap of the rotor-stator *** steady state mixing plane approach is employed at the interface to couple the rotor and stator *** show that the location of mixing plane interface in the air gap plays an important role in the prediction of heat transfer on the pole ***,it is indicated that the prediction of temperature distribution on the pole face is greatly affected by the turbulence models ***,through a comparison between the pure convective and conjugate heat transfer methodologies,it is shown that the inclusion of solid domain into the numerical model significantly improves the thermal prediction of the solid components of the machine.

关键词： hydro-generators electrical cooling mixing plane windage loss conjugate heat transfer

Long-Term Improvement in Precautions for Flood Risk Mitigation:A Case Study in the Low-Lying Area of Central Vietnam

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International Journal of Disaster Risk Science 2021年第2期12卷 250-266页

作者： Cong dinh nguyen Funiikazu Ubukata Quang Tan nguyen Hoang Ha Vo Graduate School of Environmental and Life Science Okayama UniversityOkayama 700-8530Japan Faculty of Economics and Development Studies University of EconomicsHue UniversityHue City 49000Vietnam International School Hue UniversityHue City 49000Vietnam

Local actors appear as inseparable components of the integrated flood risk mitigation strategy in *** this fact,this study examined the long-term improvement in precautions taken by commune authorities and households between two major floods in 1999 and 2017 by applying both quantitative and qualitative *** flood-prone villages were selected for a survey;one in a rural area and the other in a suburban area of Thua Thien Hue Province,central *** findings indicate that most villagers doubted the structural works’efficacy and were dissatisfied with the current efforts of local ***’self-preparation thus became the decisive factor in mitigating *** most households have paid greater attention to flood precautions in 2017,others seem to be ***-related barriers were the root causes restraining households in both rural and suburban *** suburban riverine residents were further identified as vulnerable by their limitations in upgrading structural measures,which was ascribed to the inconsistency in the ancient town’s preservation *** multidimensional comparison,in terms of vulnerability,emphasized the importance of space-function links in the suburb and the contradictions of different policy initiatives,such as landscape rehabilitation,disaster prevention,and livelihood maintenance.

关键词： Central Vietnam Flood risk mitigation Long-term improvement Natural hazards Precautionary measures

Regularization of the Inverse Problem for Time Fractional Pseudo-parabolic Equation with Non-local in Time Conditions

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Acta Mathematica Sinica,English Series 2022年第12期38卷 2199-2219页

作者： nguyen Duc PHUONG Le dinh LONG Anh Tuan nguyen Dumitru BALEANU Faculty of Fundamental Science Industrial University of Ho Chi Minh CityVietnam Division of Applied Mathematics Science and Technology Advanced InstituteVanLang UniversityHoChi Minh CityVietnam Faculty of Technology Van Lang UniversityHo Chi Minh CityVietnam Department of Mathematics Cankaya UniversityAnkaraTurkey Lebanese AmericanUniversity BeirutLebanon Institute of Space Sciences Magurele-BucharestRomania

This paper is devoted to identifying an unknown source for a time-fractional diffusion equation in a general bounded ***,we prove the problem is non-well posed and the stability of the source ***,by using the Modified Fractional Landweber method,we present regularization solutions and show the convergence rate between regularization solutions and sought solution are given under a priori and a posteriori choice rules of the regularization parameter,***,we present an illustrative numerical example to test the results of our theory.

关键词： Source problem fractional pseudo-parabolic problem ill-posed problem convergence estimates regularization