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Random vibration analysis of FGM plates subjected to moving load using a refined stochastic finite element method

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Defence Technology（防务技术） 2024年第4期34卷 42-56页

作者： ngoc-Tu Do Trung Thanh tran Faculty of Mechanical Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiViet Nam

The article introduces a finite element procedure using the bilinear quadrilateral element or four-node rectangular element(namely Q4 element) based on a refined first-order shear deformation theory(rFSDT) and Monte Carlo simulation(MCS), so-called refined stochastic finite element method to investigate the random vibration of functionally graded material(FGM) plates subjected to the moving *** advantage of the proposed method is to use r-FSDT to improve the accuracy of classical FSDT, satisfy the stress-free condition at the plate boundaries, and combine with MCS to analyze the vibration of the FGM plate when the parameter inputs are random quantities following a normal distribution. The obtained results show that the distribution characteristics of the vibration response of the FGM plate depend on the standard deviation of the input parameters and the velocity of the moving ***, the numerical results in this study are expected to contribute to improving the understanding of FGM plates subjected to moving loads with uncertain input parameters.

关键词： FGM Moving load R-FSDT Q4 element Monte Carlo simulation Random vibration

Exploring the Interplay between Job Stress,Work Performance,and Attitudes toward Professional Psychological Help among Employees

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International Journal of Mental Health Promotion 2024年第7期26卷 531-545页

作者： Cong minh Le Son Van Huynh Ky Luu Quynh-Nhi ngoc Ho Van thi Le Nguyen Vinh-Long tran-Chi Center for Mental Health Research and Support University of Social Sciences and HumanitiesVietnam National University Ho Chi Minh CityHo Chi Minh City700000Vietnam Faculty of Psychology Ho Chi Minh City University of EducationHo Chi Minh City700000Vietnam Faculty of Tourism College of BusinessUniversity of Economics Ho Chi Minh CityHo Chi Minh City700000Vietnam Scientific Management Department Dong A UniversityDa Nang500000Vietnam

Objective:this study explores the interplay between job stress,job-related factors,work performance,and attitudes toward seeking professional psychological help among Vietnamese ***:A total of 374 employees in Vietnam were surveyed using random sampling and an online questionnaire from November 07 to November 28,*** data and self-reported from three scales:The New Job Stress Scale(NJSS),Work Performance(WP),and Attitudes Toward Seeking Professional Psychological Help(ATSPPH_SF)were ***:Significant variations were found across several variables,including forms of work,operating hours,education levels,monthly income,numbers of daily working hours,and the presence of a psychological counseling department within the *** analysis has highlighted direct relationships between key latent *** who were more open to seeking professional help tended to report higher levels of job *** negative relationship was found between job stress and attitudes toward seeking professional ***,work effort was positively associated with work *** analyses revealed the influence of co-worker support on role expectation conflict and work effort,role expectation conflict and work-life balance,as well as interactions between role expectation conflict and attitudes needed toward seeking professional *** analyses showed that work effort mediated relationships between openness to seeking professional help,co-worker support,work-life balance,role expectation conflict,and work *** toward seeking professional help also mediated relationships between work-life balance,job stress,and work ***:The study highlights the complex dynamics surrounding job stress,job-related factors,work performance,and attitudes toward seeking professional psychological help among Vietnamese *** highlights the importance of addressing help-seeking barriers,promoting work engagement

关键词： Stress co-worker support work-life balance role expectation conﬂict professional psychological help-seeking

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 Tuan-Anh Pham N.Diep Nguyen B.ngoc tran 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

An Analytical Approach for Nonlinear Buckling Analysis of Torsionally Loaded Sandwich Carbon Nanotube Reinforced Cylindrical Shells with Auxetic Core

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Advances in Applied Mathematics and Mechanics 2023年第2期15卷 468-484页

作者： Dang Thuy Dong Nguyen thi Phuong Vu Hoai Nam Le ngoc Ly Nguyen Van Tien Vu minh Duc tran Quang minh Vu Tho Hung Nguyen thi Huong Giang Faculty of Civil Engineering University of Transport TechnologyHanoi 100000Vietnam Graduate School of Advanced Science and Engineering Hiroshima University1-4-1 KagamiyamaHigashi-HiroshimaHiroshima 739-8527Japan Faculty of Fundamental Science for Engineering University of Transport TechnologyHanoi 100000Vietnam

The main aim of this paper is to present an analytical approach on the postbuckling for torsionally loaded sandwich carbon nanotube(CNT)reinforced cylindrical shells with the auxetic *** considered shells consist of three layers,external and internal CNT reinforced layers,and the auxetic lattice core made by isotropic *** homogenization model for honeycomb auxetic lattice core is utilized,and the equilibrium equations are formulated based on the nonlinear Donnell’s thin shell theory with von Karman geometrical *** three terms of deflection are considered,the Airy’s stress function and Galerkin’s method are utilized,the explicit expression of critical buckling of torsionally loaded shells and load-deflection expression of postbuckling states are *** effects of two carbon nanotube reinforced layers,the auxetic core layer,the volume fraction of carbon nanotube on the torsional buckling behavior are examined and remarked.

关键词： Nonlinear postbuckling carbon nanotube reinforced composite cylindrical shell torsion auxetic core

BTEX pollution caused by motorcycles in the megacity of HoChiminh

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Journal of Environmental Sciences 2013年第2期25卷 348-356页

作者： tran thi ngoc Lan Pham Anh minh University of Science Vietnam National University227 Nguyen Van CuHoChiMinh 70000Vietnam

Monitoring of benzene, toluene and xylenes （BTEX） was conducted along with traffic counts at 17 roadside sites in urban areas of HoChiminh. Toluene was the most abundant substance, followed by p,m-xylenes, benzene, o-xylene and ethylbenzene. The maximum observed hour-average benzene concentration was 254 μg/m3 . Motorcycles contributed to 91% of the traffic fleet. High correlations among BTEX species, between BTEX concentrations and the volume of on-road motorcycles, and between inter-species ratios in air and in gasoline indicate the motorcycle-exhaust origin of BTEX species. Daily concentrations of benzene, toluene, ethylbenzene, p,m-xylenes and o-xylene were 56, 121, 21, 64 and 23 μg/m 3 , respectively. p,m-xylenes possess the highest ozone formation potential among the BTEX family.

关键词： air pollution benzene BTEX HoChiminh motorcycle exhaust

Effects of parental age on offspring growth and survival in both wild and domesticated strains of bighead catfish(Clarias macrocephalus Günther,1864)

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Aquaculture and Fisheries 2023年第2期8卷 141-147页

作者： Thuy Yen Duong Thet Su Win thi ngoc tran Nguyen College of Aquaculture and Fisheries Can Tho UniversityCan Tho920000Viet Nam International Master Program in Aquaculture Course 4Can Tho UniversityCan Tho920000Viet Nam

Understanding the relationship between fish parental age and offspring performance over their life cycle is crucial for *** study investigates the effect of parental age for both 1-and 2-year-old fish on the growth and survival rates of their larval to grow-out stages for two wild and domesticated strains of bighead catfish(Clarias macrocephalus).Fish were sampled from the Vietnamese Mekong Delta where wild adult fish were collected from a conservation area in Ca Mau Province and domesticated fish were taken from a hatchery in Can *** offspring treatments of 1-and 2-year-old broodstock strains were reared for 3 successive periods:40 days for fingerling rearing in static tanks with water exchange,60 days for juveniles,and 90 days for grow-out in recirculating *** final weight of fish at 190 days varied from 96.7 to 144.7 *** growth of offspring was not affected by parental age(P>0.05),over the 3 rearing ***,the domesticated fish strain showed significantly better growth rates than the wild fish strain(P<0.05).Feed conversion ratios were comparable across fish *** rates did not differ at the fingerling(21.8%-36.4%)and juvenile(69.0%-73.3%)***,significant differences were found at the grow-out stage(69.3%-84.0%),with offspring from 2-year-old parents of both strains having greater survival ***,1-and 2-year-old fish appear to be suitable for bighead catfish breeders.

关键词： Parental age Clarias catfish Fish growth Strain evaluation Wild broodstock

The future of COVID-19 vaccination rates for children

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Asian Pacific Journal of Tropical Medicine 2022年第9期15卷 381-382页

作者： Giao Huynh Kimberly H.Nguyen Han thi ngoc Nguyen Tuan Diep tran Pham Le An Faculty of Public Health University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam Department of Public Health and Community Medicine Tufts University School of MedicineBostonMAUSA Infection Control Department University Medical Center Ho Chi Minh CityHo Chi Minh CityVietnam Faculty of Medicine University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam Family Medicine Training Center University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam

The COVID-19 pandemic has been ongoing for over two years since the first case was reported in the end of January *** has successfully controlled the pandemic through its vaccination campaign,targeted messages and applications of various public health interventions including social distancing,quarantining,masking,and hand washing,which have made some significant achievements in reducing hospitalizations and deaths[1].

关键词： vaccination targeted COV

“Nanospace engineering”by the growth of nano metal-organic framework on dendritic fibrous nanosilica(DFNS)and DFNS/gold hybrids

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Nano Research 2020年第3期13卷 775-784页

作者： ngoc minh tran Soeun Jung Hyojong Yoo Department of Materials Science and Chemical Engineering Hanyang UniversityAnsanGyeonggi-do15588Republic of Korea

Advanced hybrid nanomaterials(nanohybrids)with unique tailored morphologies and compositions have been used for the target-oriented catalysts due to the structural or supportive properties of each moiety and the synergistic properties of the individual *** rational design and development of nanohybrids by integrating highly porous silica into a nano metal-organic framework(NMOF)are expected to enable unique nanospace engineering in the resulting systems to optimize their utility in the target ***,we report the design and fabrication of advanced nanohybrids composed of dendritic fibrous nanosilica(DFNS)and DFNS/gold(DFNS/Au)hybrids as the core and zinc-based NMOF(Zn-NMOF)as the shell(DFNS@Zn-NMOF)through a solution-based *** combined fibrous morphology of DFNS and micropores of NMOF can be directly employed for nanospace engineering in the resulting multi-compositional and hierarchical systems in a controllable *** DFNS/Au dots@Zn-NMOF nanohybrid shows improved catalytic performance in the Knoevenagel condensation reaction,attributed mainly to the cooperative effect stemming from the suitably organized configurations of each component.

关键词： nanohybrids nanospace engineering dendritic fibrous nanosilica nano metal-organic framework cooperative catalytic performance

Fabrication of zinc-based coordination polymer nano-cubes and post-modification through copper decoration

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Nano Research 2018年第11期11卷 5890-5901页

作者： ngoc minh tran Hien Duy Mai Hyojong Yoo Department of Chemistry Hallym University Chuncheon Gangwon-do 24252 Republic of Korea

Coordination polymer particles (CPPs) with a high degree of porosity and multi-functional reaction sites are promising for diverse applications. The integration of open sites favorable for the post-modification of CPPs presents a unique opportunity for the rational design of inorganic materials with target-oriented functions. Herein, we report a shape-controllable synthetic protocol for zinc-based coordination polymer nanocubes (Zn-CPNs). In the synthesis, 2,6-bis[(4-carboxyanilino)carbonyl] pyridine ([N3]) ligand is employed as an efficient shape-directing modulator to control the size and shape of Zn-CPNs. More importantly, the [N3] ligand provides metal binding sites suitable for the decoration of other functional metals such as copper ions. The copper-modified Zn-CPNs (Cu_Zn-CPNs) show good activities in a heterogeneous catalytic reaction.

关键词： zinc-based coordination polymer nanocubes shape-directing modulator size and shape controls post-modification heterogeneous catalytic reaction