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Applied Mathematics and Mechanics(English Edition) 2017年第5期38卷 647-670页

作者： D.V.DUNG N.T.NGA l.k.hoa Faculty of Mathematics Mechanics and InformaticsVietnam National UniversityHanoi 100000Vietnam Faculty of Basic Science Military Logistic AcademyHanoi 100000Vietnam

In this paper, Donnell＇s shell theory and smeared stiffeners technique are improved to analyze the postbuckling and buckling behaviors of circular cylindrical shells of stiffened thin functionally graded material （FGM） sandwich under an axial loading on elastic foundations, and the shells are considered in a thermal environment. The shells are stiffened by FGM rings and stringers. A general sigmoid law and a general power law are proposed. Thermal elements of the shells and reinforcement stiffeners are considered. Explicit expressions to find critical loads and postbuckling load-deflection curves are obtained by applying the Galerkin method and choosing the three-term approximate solution of deflection. Numerical results show various effects of temperature, elastic foundation, stiffeners, material and geometrical properties, and the ratio between face sheet thickness and total thickness on the nonlinear behavior of shells.

关键词： functionally graded material (FGM) stiffened cylindrical shell sandwich,thermal environment

Buckling analysis of functionally graded material(FGM) sandwich truncated conical shells reinforced by FGM stiffeners filled inside by elastic foundations

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Applied Mathematics and Mechanics(English Edition) 2016年第7期37卷 879-902页

作者： D.V.DUNG l.k.hoa B.T.THUYET N.T.NGA Faculty of Mathematics Mechanics and Informatics Vietnam National University Faculty of Basic Science Military Logistic AcademyHanoi Faculty of Mining Hanoi University of Mining and Geology

An analytical solution for buckling of an eccentrically stiffened sandwich truncated conical shell is investigated. The shell consists of two functionally graded material （FGM） coating layers and a core layer which are metal or ceramic subjected to an axial compressive load and an external uniform pressure. Shells are reinforced by stringers and rings, in which the material properties of shells and stiffeners are graded in the thickness direction following a general sigmoid law distribution. Two models of coated shell-stiffener arrangements are investigated. The change of the spacing between stringers in the meridional direction is taken into account. A couple set of three-variable- coefficient partial differential equations in terms of displacement components are solved by the Galerkin method. A closed-form expression for determining the buckling load is obtained. The numerical examples are presented and compared with previous works.

关键词： functionally graded material (FGM) sandwich truncated conical shell,stiffener elastic foundation buckling analysis

High-thermal free vibration analysis of functionally graded microplates using a new finite element formulation based on TSDT and MSCT

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Defence Technology 2025年第2期44卷 131-149页

作者： Huu Trong Dang Nhan Thinh hoang Quoc hoa Pham Trung Thanh Tran Huy Gia luong Faculty of Mechanical Engineering Technology Vinh Long University of Technology Education Institute for Creative Design and Business Nguyen Tat Thanh University Faculty of Engineering and Technology Nguyen Tat Thanh University Faculty of Mechanical Engineering Le Quy Don Technical University Techno Star Vietnam Techno Star Co.Ltd

Recent advancements in additive manufacturing(AM) have revolutionized the design and production of complex engineering microstructures. Despite these advancements, their mathematical modeling and computational analysis remain significant challenges. This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG) microplates under high temperatures while resting on a Pasternak foundation(PF). This formulation leverages a new thirdorder shear deformation theory(new TSDT) for improved accuracy without requiring shear correction factors. Additionally, the modified couple stress theory(MCST) is incorporated to account for sizedependent effects in microplates. The PF is characterized by two parameters including spring stiffness(kw) and shear layer stiffness(ks). To validate the proposed method, the results obtained are compared with those of the existing literature. Furthermore, numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates. These factors include the length scale parameter(l), geometric dimensions, material properties, and the presence of the elastic foundation. The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments. In addition, the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments. In addition, the results of this research will have great potential in military and defense applications such as components of submarines, fighter aircraft, and missiles.

关键词： Microplates Functionally graded material Finite element method Modified couple stress theory New TSDT High-thermal free vibration Pasternak foundation

A novel finite element formulation for static bending analysis of functionally graded porous sandwich plates

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Frontiers of Structural and Civil Engineering 2022年第12期16卷 1599-1620页

作者： Van Chinh NGUYEN Trung Thanh TRAN Trung NGUYEN-THOI Quoc-hoa PHAM Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiVietnam laboratory for Applied and Industrial Mathematics Institute for Computational Science and Artificial IntelligenceVan Lang UniversityHo Chi Minh CityVietnam Faculty of Mechanical-Electrical and Computer Engineering Van Lang UniversityHo Chi Minh CityVietnam Faculty of Engineering and Technology Nguyen Tat Thanh UniversityHo Chi Minh CityVietnam

This article aims to propose a finite element formulation based on Quasi-3D theory for the static bending analysis of functionally graded porous(FGP)sandwich *** FGP sandwich plates consist of three layers including the bottom skin of homogeneous metal,the top skin of fully ceramic and the FGP core layer with uneven porosity distribution.A quadrilateral(Q4)element with nine degrees of freedom(DOFs)per node is derived and employed in analyzing the static bending response of the plate under uniform and/or sinusoidally distributed *** accuracy of the present finite element formulation is verified by comparing the obtained numerical results with the published results in the ***,some numerical examples are performed to examine the effects of the parameters including power-law index k and porosity coefficient on the static bending response of rectangular FGP sandwich *** addition,a problem with a complicated l-shape model is conducted to illustrate the superiority of the proposed finite element method.

关键词： sandwich plates functionally graded porous static bending Quasi-3D theory Q4 element

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Photocatalytic degradation of antibiotic sulfamethizole by visible light activated perovskite laZnO_(3)

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Journal of Environmental Sciences 2024年第10期144卷 212-224页

作者： Bui The Huy XCuong Nguyen Vu khac hoang Bui Nguyen Ngoc Tri Iqra Rabani Nhu hoa Thi Tran Quang Viet ly Hai Bang Truong Major of Biomedical Engineering Division of Smart HealthcareCollege of Information Technology and ConvergencePukyong National UniversityBusan 48513Korea Center for Advanced Chemistry Institute of Research and DevelopmentDuy Tan UniversityDa Nang 550000Viet Nam Faculty of Environmental and Chemical Engineering Duy Tan UniversityDa Nang 550000Viet Nam Department of Environment and Energy Sejong UniversitySeoul 05006Korea lab of Computational Chemistry and Modelling Department of ChemistryFaculty of Natural SciencesQuy Nhon UniversityQuy NhonViet Nam Department of Nanotechnology and Advanced Materials Engineering Sejong UniversitySeoul 05006Korea Faculty of Materials Science and Technology University of ScienceHo Chi Minh City 700000Viet Nam Vietnam National University Ho Chi Minh City 700000Viet Nam Department of Environmental Engineering Seoul National University of Science and TechnologySeoul 01811Korea 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

In thiswork,the perovskite laZnO_(3) was synthesized via sol-gel method and applied for photocatalytic treatment of sulfamethizole(SMZ)antibiotics under visible light *** was almost completely degraded(99.2%±0.3%)within 4 hr by photocatalyst laZnO_(3) at the optimal dosage of 1.1 g/l,with amineralization proportion of 58.7%±0.4%.The efficient performance of laZnO_(3) can be attributed to itswide-range light absorption and the appropriate energy band edge levels,which facilitate the formation of active agents such as·O_(2)^(−),h^(+),and·*** integration of RP-HPlC/Q-TOF-MS and DFT-based computational techniques revealed three degradation pathways of SMZ,which were initiated by the deamination reaction at the aniline ring,the breakdown of the sulfonamidemoieties,and a process known as Smile-type rearrangement and SO2 *** toxicity of SMZ and the intermediateswere analyzed by quantitative structure activity relationship(QSAR),indicating the effectiveness of laZnO_(3)-based photocatalysis in preventing secondary pollution of the intermediates to the ecosystem during the degradation *** visible-light-activated photocatalyst laZnO_(3) exhibited efficient performance in the occurrence of inorganic anions and maintained high durability across multiple recycling tests,making it a promising candidate for practical antibiotic treatment.

关键词： Perovskite Antibiotics Photocatalysis Density functional theory Toxicity

MEMS inductor fabrication and emerging applications in power electronics and neurotechnologies

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Microsystems & Nanoengineering 2021年第4期7卷 1-22页

作者： hoa Thanh le Rubaiyet I.Haque Ziwei Ouyang Seung Woo lee Shelley I.Fried Ding Zhao Min Qiu Anpan Han The Rowland Institute at Harvard Harvard UniversityCambridgeMAUSA Department of Mechanical Engineering Technical University of DenmarkLyngbyDenmark Department of Electrical Engineering Technical University of DenmarkLyngbyDenmark Department of Neurosurgery Massachusetts General HospitalHarvard Medical SchoolBostonMAUSA Boston VA Healthcare System BostonMAUSA key laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province School of EngineeringWestlake UniversityHangzhouChina Institute of Advanced Technology Westlake Institute for Advanced StudyHangzhouChina

MEMS inductors are used in a wide range of applications in micro-and nanotechnology,including RF MEMS,sensors,power electronics,and *** technologies set the boundary conditions for inductor design and their electrical and mechanical *** review provides a comprehensive overview of state-of-the-art MEMS technologies for inductor fabrication,presents recent advances in 3D additive fabrication technologies,and discusses the challenges and opportunities of MEMS inductors for two emerging applications,namely,integrated power electronics and *** the four top-down MEMS fabrication approaches,3D surface micromachining and through-substrate-via(TSV)fabrication technology have been intensively studied to fabricate 3D inductors such as solenoid and toroid in-substrate TSV *** 3D inductors are preferred for their high-quality factor,high power density,and low parasitic capacitance,in-substrate TSV inductors offer an additional unique advantage for 3D system integration and efficient thermal *** features make in-substrate TSV inductors promising to achieve the ultimate goal of monolithically integrated power *** another perspective,3D bottom-up additive techniques such as ice lithography have great potential for fabricating inductors with geometries and specifications that are very challenging to achieve with established MEMS ***,we discuss inspiring and emerging research opportunities for MEMS inductors.

关键词： inductor power lithography

Radiologic anatomy of the round window relevant to cochlear implantation and inner ear drug delivery

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World Journal of Otorhinolaryngology-Head and Neck Surgery 2021年第1期7卷 9-16页

作者： Nguy Peter l. Saidha Sheela Jay Ann kim H.Jeffrey hoa Michael Department of Otolaryngology-Head and Neck Surgery Georgetown University Medical CenterWashington DCUSA Department of Otolaryngology University of Rochester Medical CenterRochesterNYUSA Department of Radiology Georgetown University Medical CenterWashington DCUSA

Objective:To determine anatomic relationships and variation of the round window membrane to bony surgical landmarks on computed *** design:Retrospective imaging ***:100 temporal bone images were *** measurements were obtained for membrane *** distances and angulation from umbo and bony annulus were calculated from image viewer software ***:The angle of round window membrane at junction with cochlear basal turn was(42.1±8.6)°.The membrane’s position relative to plane of the facial nerve through facial recess was(14.7±5.2)°posterior from a reference line drawn through facial recess to carotid *** transtympanic drug delivery,the round window membrane was directed 4.1 mm superiorly from the inferior annulus and 5.4 mm anteriorly from the posterior *** round window membrane on average was angled superiorly from the inferior annulus(77.1±27.9)°and slightly anteriorly from the posterior annulus(19.1±11.1°).The mean distance of round window membrane from umbo was 4 mm and posteriorly rotated 30°clockwise from a perpendicular drawn from umbo to inferior annulus towards posterior ***,these measurements approximate the round window membrane in the tympanic membrane’s posteroinferior ***:These radiologic measurements demonstrate normal variations seen in round window anatomy relative to facial recess approach and bony tympanic annulus,providing a baseline to assess round window insertion for cochlear implantation and outlines anatomic factors affecting transtympanic drug delivery.

关键词： Round window Cochlear implantation Transtympanic drug delivery Computed tomography

ON CONCRETE EXAMPlES AND THE ABSTRACT THEORY OF THE GENERAlIZED ANAlYTIC FUNCTIONS

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Science in China,Ser.A 1963年第9期 1269-1283页

作者：闵嗣鹤 Peking University

I. INTRODUCTION Unlike the theory of analytic functions, the theory of generalized analytic functions or pseudo-analytic functions as developed by H. H. Bekya and l. Bers independently, consists of a great number of existence theorems without concrete examples. An objective of this paper is to treat some typical special cases with the aim of obtaining very concrete results. On the other hand we shall make the first attempt of building up an abstract theory of certain operators on some Banach spaces, which will include the theory of generalized analytic functions as a special case.

关键词： ON CONCRETE EXAMPlES AND THE ABSTRACT THEORY OF THE GENERAlIZED ANAlYTIC FUNCTIONS

Spatio-Temporal Analysis of Drought in the North-Eastern Coastal Region of Vietnam Using the Standardized Precipitation Index (SPI)

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Atmospheric and Climate Sciences 2023年第2期13卷 175-200页

作者： Nguyen Van Tuan Nguyen Van Hieu Nguyen khac Bang Pham hoang Hai Nguyen khanh Van le Vinh Ha Tran Thi hoa lê Trọng Hiếu Institute of Water Resources Planning Hanoi Vietnam Institute of Environment and Public Health Vietnam Union of Science and Technology Associations Hanoi Vietnam Thai Binh University Thai Binh Vietnam Faculty of Electronics and Telecommunications Electric Power University Hanoi Vietnam

Spatio-temporal analysis of drought provides valuable information for drought management and damage mitigation. In this study, the Standardized Precipitation Index at the time scale of 6 months (SPI-6) is selected to reflect drought conditions in the North-Eastern coastal region of Vietnam. The drought events and their characteristics from 1981 to 2019 are detected at 9 meteorological stations and 10 Chirps rainfall stations. The spatio-temporal variation of drought in the study region is analyzed on the basis of the number, duration, severity, intensity, and peak of the detected drought events at the 19 stations. The results show that from 1981 to 2019 the drought events mainly occurred with 1-season duration and moderate intensity and peak. The number, duration, severity, and peak of the drought events were the greatest in the period 2001-2010 and were the smallest in the period 2011-2019. Among the 19 stations, the drought duration tends to decrease at 11 stations, increase at 7 stations, and has a slight variant at 1 station;the drought severity tends to decrease at 14 stations, increase at 4 stations, and has not a significant trend at 1 station;the drought intensity tends to decrease at 17 stations, increase at 1 station, and has a slight variant at 1 station;and the drought peak tends to decrease at 18 stations and increase at 1 station.

关键词： Spatio-Temporal Analysis of Drought Standardized Precipitation Index (SPI) Drought Characteristics

Evaluation of the Pathogenicity and Immune Response of Nervous Necrosis Virus Isolated in Vietnam

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Journal of Agricultural Science and Technology(A) 2014年第4期4卷 315-322页

作者： Pham Thi Tam Pham Cong hoat Bui Thi Hai hoa Nguyen Thi Thu Hien Faculty of Biotechnology Hanoi Open University Hanoi 101 Vietnam Department of Science and Technology for Economic Technical Branches Min&try of Science and Technology Hanoi 113 Vietnam

Eight strains of nervous necrosis virus （NNV） isolated in Vietnam were used to detect the pathogenicity and immune response in sea bass （SB）. All strains induced cytopathic effect in SB cell line, complete destruction of monolayer of cells appeared after seven days post infection （dpi）. Virus titer was different for each strain, TCIDso ranged from 102.7 to 1069, and lDs0 from 1015 to 1075. Five NNV strains named QN 02, QN 05, QN 07, ND 11 and kH 05 had higher virulence than the other three, the first causing 100% mortality in experimental fish 3-5 dpi. NNV kH 05 had the highest antigenic similarity, and it was inactivated completely by 0.2% formalin, 0.002 mol/l binary ethylenimine （BEI） and 0.1% beta-propiolactone. The neutralization antibody titer obtained in fish of groups immunized by BEI 0.002 M and beta-propiolactone 0.1% inactivated virus was four to eight times higher than that of the group treated with the formalin inactivated virus. The antibody titer in fish immunized with beta-propiolactone inactivated virus was more persistent. The efficacy of vaccines developed from beta-propiolactone inactivated virus and aluminium hydroxide （AH） or aluminum phosphate （AP） was observed by intramuscularly immunizing Epinephelusfuscoguttatus size 1.5 cm. Neutralizing antibodies appeared in vaccinated fish on 10th day post-immunization （dpi） at a dilution of 1：16; 1：32 and highest levels were reached on 30-45 dpi, at dilutions of 1：256 and 1：512, after treatment with AH and AP vaccine, respectively. The relative percent of survival （RPS） of vaccine at 30 dpi was highest with challenge doses 0.2-1 × 10^6.8 TCIDs0, the RPS varied from 80%-83.3% in both groups of AH and AP immunization. This result provides the basis for developing a vaccine against NNA disease.

关键词： Grouper NNV TCID50 lD50 neutralization antibody RPS