检索结果-南通市图书馆

A deep neural network based surrogate model for damage identification in full-scale structures with incomplete noisy measurements

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2024年第3期18卷 393-410页

作者： tram BUI-NGOC Duy-Khuong LY tam t tRUONG Chanachai tHONGCHOM t.nguyen-tHOI Laboratory for Computational Mechanics Institute for Computational Science and Artificial IntelligenceVan Lang UniversityHo Chi Minh City 70000Vietnam Faculty of Mechanical-Electrical and Computer Engineering School of TechnologyVan Lang UniversityHo Chi Minh City 70000Vietnam Faculty of Civil Engineering School of TechnologyVan Lang UniversityHo Chi Minh City 70000Vietnam Department of Computer Science Aarhus UniversityAarhus 8000Denmark thammasat University research unit in structural and foundation engineering Department of Civil EngineeringThammasat UniversityPathumthani 12120Thailand Laboratory for Applied and Industrial Mathematics Institute for Computational Science and Artificial IntelligenceVan Lang UniversityHo Chi Minh City 70000Vietnam thammasat School of Engineering Thammasat UniversityPathumthani 12120Thailand

the paper introduces a novel approach for detecting structural damage in full-scale structures using surrogate models generated from incomplete modal data and deep neural networks(DNNs).A significant challenge in this field is the limited availability of measurement data for full-scale structures,which is addressed in this paper by generating data sets using a reduced finite element(FE)model constructed by SAP2000 software and the MAtLAB programming *** surrogate models are trained using response data obtained from the monitored structure through a limited number of measurement *** proposed approach involves training a single surrogate model that can quickly predict the location and severity of damage for all potential *** achieve the most generalized surrogate model,the study explores different types of layers and hyperparameters of the training algorithm and employs state-of-the-art techniques to avoid overfitting and to accelerate the training *** approach’s effectiveness,efficiency,and applicability are demonstrated by two numerical *** study also verifies the robustness of the proposed approach on data sets with sparse and noisy measured ***,the proposed approach is a promising alternative to traditional approaches that rely on FE model updating and optimization algorithms,which can be computationally *** approach also shows potential for broader applications in structural damage detection.

关键词： vibration-based damage detection deep neural network full-scale structures finite element model updating noisy incomplete modal data

tuning the crystal structure and optical properties of selective area grown InGaAs nanowires

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2022年第4期15卷 3695-3703页

作者： Zahra Azimi Aswani Gopakumar Amira SAmeruddin Li Li thien truong hieu tnguyen Hark Hoe tan Chennupati Jagadish Jennifer Wong-Leung Department of Electronic Materials Engineering Research School of PhysicsThe Australian National UniversityCanberra ACT 2601Australia Faculty of Applied Science and technology Universiti Tun Hussein Onn MalaysiaBatu Pahat 86400Malaysia Australian National Fabrication Facility ACt Node Research School of PhysicsThe Australian National UniversityCanberra ACT 2601Australia School of Engineering The Australian National UniversityCanberra ACT 2601Australia Australian Research Council Centre of Excellence for transformative Meta-Optical Systems Research School of PhysicsThe Australian National UniversityCanberra ACT 2601Australia

Catalyst-free InGaAs nanowires grown by selective area epitaxy are promising building blocks for future optoelectronic devices in the infrared spectral *** progress,the role of pattern geometry and growth parameters on the composition,microstructure,and optical properties of InGaAs nanowires is still ***,we present an optimised growth parameter window to achieve highly uniform In1-xGaxAs nanowire arrays on GaAs(111)B substrate over an extensive range of Ga concentrations,from 0.1 to 0.91,by selective-area metal-organic vapor-phase *** observe that the Ga content always increases with decreasing In/(Ga+In)precursor ratio and group V flow rate and increasing growth *** increase in Ga content is supported by a blue shift in the photoluminescence peak *** geometry of the nanowire arrays also plays an important role in the resulting ***,increasing the nanowire pitch size from 0.6 to 2μm in a patterned array shifts the photoluminescence peak emission by up to 120 *** of these growth and geometry parameters,the Ga content determines the crystal structure,resulting in a predominantly wurtzite structure for xGa≤0.3 and a predominantly zinc blende phase for xGa≥*** insights on the factors controlling the composition of InGaAs nanowires grown by a scalable catalyst-free approach provide directions for engineering nanowires as functional components of future optoelectronic devices.

关键词： InGaAs nanowires ternary semiconductors selective-area metal-organic vapor-phase epitaxy nanostructure pattern geometry

Chebyshev polynomial-based Ritz method for thermal buckling and free vibration behaviors of metal foam beams

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 891-910页

作者： N.D.nguyen t.N.nguyen Faculty of Civil Engineering Ho Chi Minh City University of Technology and EducationHo Chi Minh City 71309Viet Nam Faculty of Engineering and technology Kien Giang UniversityChau Thanh 92000Viet Nam

this study presents the Chebyshev polynomials-based Ritz method to examine the thermal buckling and free vibration characteristics of metal foam *** analyses include three models for porosity distribution and two scenarios for thermal *** material properties are assessed under two conditions,i.e.,temperature dependence and temperature *** theoretical framework for the beams is based on the higher-order shear deformation theory,which incorporates shear deformations with higher-order *** governing equations are established from the Lagrange equations,and the beam displacement fields are approximated by the Chebyshev *** simulations are performed to evaluate the effects of thermal load,slenderness,boundary condition(BC),and porosity distribution on the buckling and vibration behaviors of metal foam *** findings highlight the significant influence of temperature-dependent(tD)material properties on metal foam beams'buckling and vibration responses.

关键词： Ritz method Chebyshev function buckling vibration metal foam beam higher-order beam theory(HOBt)

Supertransport of excitons in atomically thin organic semiconductors at the 2D quantum limit

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2020年第1期9卷 907-919页

作者： Ankur Sharma Linglong Zhang Jonathan O.tollerud Miheng Dong Yi Zhu Robert Halbich tobias Vogl Kun Liang hieu t.nguyen Fan Wang Shilpa Sanwlani Stuart K.Earl Daniel Macdonald Ping Koy Lam Jeffrey A.Davis Yuerui Lu Research School of Electrical Energy and Materials EngineeringCollege of Engineering and Computer ScienceThe Australian National UniversityCanberraACT 2601Australia Optical Sciences Centre Swinburne University of TechnologyHawthornVIC 3122Australia ARC Centre of Excellence for Future Low-Energy Electronics technology Australia Centre for Quantum Computation and Communication technology Department of Quantum ScienceResearch School of Physics and EngineeringThe Australian National UniversityActonACT 2601Australia School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China Institute for Biomedical Materials and Devices(IBMD) Faculty of ScienceUniversity of Technology SydneySydneyNSW 2007Australia

Long-range and fast transport of coherent excitons is important for the development of high-speed excitonic circuits and quantum computing ***,most of these coherent excitons have only been observed in some low-dimensional semiconductors when coupled with cavities,as there are large inhomogeneous broadening and dephasing effects on the transport of excitons in their native states in ***,by confining coherent excitons at the 2D quantum limit,we first observed molecular aggregation-enabled‘supertransport’of excitons in atomically thin two-dimensional(2D)organic semiconductors between coherent states,with a measured high effective exciton diffusion coefficient of ~346.9 cm^(2)/s at room *** value is one to several orders of magnitude higher than the values reported for other organic molecular aggregates and low-dimensional inorganic *** coupling to any optical cavities,the monolayer pentacene sample,a very clean 2D quantum system(~1.2 nm thick)with high crystallinity(J-type aggregation)and minimal interfacial states,showed superradiant emission from Frenkel excitons,which was experimentally confirmed by the temperature-dependent photoluminescence(PL)emission,highly enhanced radiative decay rate,significantly narrowed PL peak width and strongly directional in-plane *** coherence in monolayer pentacene samples was observed to be delocalised over~135 molecules,which is significantly larger than the values(a few molecules)observed for other organic thin *** addition,the supertransport of excitons in monolayer pentacene samples showed highly anisotropic *** results pave the way for the development of future high-speed excitonic circuits,fast OLEDs,and other optoelectronic devices.

关键词： transport quantum coherent

Beta-lactam antibiotic resistance among Escherichia coli isolates from patients with urinary tract infections in Vietnam:A systematic review and meta-analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of tropical Medicine 2024年第6期17卷 243-255,I0001-I0003页

作者： Dat t.nguyen Princess Margaret Cancer Centre University Health NetworkTorontoOntarioCanada

Objective:to investigate the evolving patterns of antimicrobial resistance against beta-lactam antibiotics in Escherichia coli isolates from urinary tract infection patients in Vietnam,covering the period from 2005 to ***:29 Descriptive studies published between 2010 and 2022 in English and Vietnamese were included in the *** on resistance rates to beta-lactam antibiotics,including cephalosporins and carbapenems,were extracted and *** pooled resistance rates were calculated using random-effects *** trends in resistance were assessed using linear regression ***:Among the beta-lactam antibiotics studied,Escherichia coli exhibited varying levels of resistance,with cephalosporins showing higher resistance rates compared to *** pooled resistance rates were 66%for cefotaxime,65%for ceftriaxone,54%for ceftazidime,and 56%for *** contrast,carbapenems demonstrated lower resistance rates,with weighted pooled resistance rates ranging from 3%to 4%for meropenem,ertapenem,and *** rates were also observed for amoxicillin/clavulanate(35%),ticarcillin/clavulanate(26%),and piperacillin/tazobactam(12%).Significant annual increases in resistance were noted for imipenem(0.56%,Pthis study highlights the critical issue of antimicrobial resistance in urinary tract infections in Vietnam and emphasizes the importance of prudent antibiotic use and the regular monitoring of resistance *** insights are useful for guiding healthcare professionals in optimizing treatment strategies and for policymakers in formulating evidence-based clinical guidelines to combat antibiotic resistance effectively.

关键词： Antimicrobial resistance Urinary tract infection Vietnam

循环三轴试验加载频率和压实度对重塑砂土液化行为的影响

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

岩土力学 2024年第6期45卷 1813-1823页

作者： tHUY Do Van tIEP Pham Duc hieu nguyen Van tHANG Pham Cao 勒奎东技术大学特殊工程技术研究所越南河内越南航空科技协会越南河内

通过对各向同性固结不排水试样进行循环三轴试验,研究了饱和重塑砂土的液化行为。试验采用恒幅正弦载荷,通过测量剪切模量、阻尼比、轴向应变和超孔隙水压力比的变化,评估了加载频率(分别为0.1、0.5、1.0 Hz)和压实度(分别为0.95、0.90... 详细信息

通过对各向同性固结不排水试样进行循环三轴试验,研究了饱和重塑砂土的液化行为。试验采用恒幅正弦载荷,通过测量剪切模量、阻尼比、轴向应变和超孔隙水压力比的变化,评估了加载频率(分别为0.1、0.5、1.0 Hz)和压实度(分别为0.95、0.90和0.80)对砂土液化行为的影响。试验结果表明,对于压实度为0.95的砂样,在5000次加载循环中,0.1 Hz的加载频率对液化过程影响甚微;而对于压实度为0.90和0.80的砂样,此频率的影响显著。对于压实度为0.80的砂样,当频率增加到0.5 Hz时几乎一加载就直接发生液化。这表明增加加载频率会加快液化速度,而增加压实度则会减慢液化速度。因此,通过一系列的试验可以模拟现场砂土在不同频率下的动荷载条件。试验结果表明,饱和砂土的液化行为由以下因素决定:(1)试样的压实度越低,液化越容易发生;(2)加载频率越高,液化越容易发生;(3)循环轴向应变越大,发生液化所需的循环次数越少;(4)超孔隙水压力随加载循环次数增加,直至试样完全液化。

关键词：液化行为加载频率循环三轴试验饱和固结不排水条件重塑砂土压实度

Advancing Wound Filling Extraction on 3D Faces:An Auto-Segmentation and Wound Face Regeneration Approach

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第5期139卷 2197-2214页

作者： Duong Q.nguyen thinh D.Le Phuong D.nguyen Nga t.K.Le H.nguyen-Xuan Department of Mathematics and Statistics Quy Nhon UniversityQuy Nhon City55100Viet Nam Applied Research Institute for Science and technology Quy Nhon UniversityQuy Nhon City55100Viet Nam CIRtECH Institute HUTECH UniversityHo Chi Minh City72308Viet Nam

Facial wound segmentation plays a crucial role in preoperative planning and optimizing patient outcomes in various medical *** this paper,we propose an efficient approach for automating 3D facial wound segmentation using a two-stream graph convolutional *** method leverages the Cir3D-FaIR dataset and addresses the challenge of data imbalance through extensive experimentation with different loss *** achieve accurate segmentation,we conducted thorough experiments and selected a high-performing model from the *** selectedmodel demonstrates exceptional segmentation performance for complex 3D facial ***,based on the segmentation model,we propose an improved approach for extracting 3D facial wound fillers and compare it to the results of the previous *** method achieved a remarkable accuracy of 0.9999993% on the test suite,surpassing the performance of the previous *** this result,we use 3D printing technology to illustrate the shape of the wound *** outcomes of this study have significant implications for physicians involved in preoperative planning and intervention *** automating facial wound segmentation and improving the accuracy ofwound-filling extraction,our approach can assist in carefully assessing and optimizing interventions,leading to enhanced patient ***,it contributes to advancing facial reconstruction techniques by utilizing machine learning and 3D bioprinting for printing skin tissue *** source code is available at https://***/SIMOGroup/WoundFilling3D.

关键词： 3D printing technology face reconstruction 3D segmentation 3D printed model

traveling wave solutions of the nonlinear Gilson-Pickering equation in crystal lattice theory

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Ocean Engineering and Science 2024年第1期9卷 40-49页

作者： A.t.nguyen O.Nikan Z.Avazzadeh Division of Applied Mathematics Science and Technology Advanced InstituteVan Lang UniversityHo Chi Minh CityVietnam Faculty of technology Van Lang UniversityHo Chi Minh CityVietnam School of Mathematics Iran University of Science and TechnologyNarmakTehranIran Department of Applied Mathematics Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China

this paper focuses on obtaining the traveling wave solutions of the nonlinear Gilson-Pickering equa-tion(GPE),which describes the prorogation of waves in crystal lattice theory and plasma *** solution of the GPE is approximated via the finite difference technique and the localized meshless radial basis function generated finite *** association of the technique results in a meshless approach that does not require linearizing the nonlinear *** the first step,the PDE is converted to a system of nonlinear ODEs with the help of the radial *** the second step,a high-order ODE solver is adopted to discretize the nonlinear ODE *** global collocation techniques pose a considerable computationl burden due to the calculation of the dense algebraic *** proposed method approx-imates differential operators over the local support domain,leading to sparse differentiation matrices and decreasing the computational *** results and comparisons are provided to confirm the efficiency and accuracy of the method.

关键词： Nonlinear Gilson–Pickering equation Soliton wave solutions Meshless technique RBF LRBF-FD Optimal shape parameter

transient responses of double-curved sandwich two-layer shells resting on Kerr's foundations with laminated three-phase polymer/GNP/fiber surface and auxetic honeycomb core subjected to the blast load

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence technology（防务技术） 2024年第5期35卷 222-247页

作者： nguyen thi Hai Van thi Hong nguyen Researcher&Lecturer Faculty of Industrial EducationThe University of Danang-University of Technology and Education48 Cao ThangDanang550000Viet Nam Researcher&Lecturer Faculty of Mechanical EngineeringThuyloi University175 Tay SonDong DaHanoi100000Viet Nam

this work uses refined first-order shear theory to analyze the free vibration and transient responses of double-curved sandwich two-layer shells made of auxetic honeycomb core and laminated three-phase polymer/GNP/fiber surface subjected to the blast *** of the two layers that make up the double-curved shell structure is made up of an auxetic honeycomb core and two laminated sheets of three-phase polymer/GNP/*** exterior is supported by a Kerr elastic foundation with three *** key innovation of the proposed theory is that the transverse shear stresses are zero at two free surfaces of each *** contrast to previous first-order shear deformation theories,no shear correction factor is ***'s exact solution was used to treat the double-curved shell problem with a single title boundary,while the finite element technique and an eight-node quadrilateral were used to address the other boundary *** ensure the accuracy of these results,a thorough comparison technique is employed in conjunction with credible *** problem model's edge cases allow for this kind of *** study's findings may be used in the post-construction evaluation of military and civil works structures for their ability to sustain explosive *** addition,this is also an important basis for the calculation and design of shell structures made of smart materials when subjected to shock waves or explosive loads.

关键词： Blast load two-layer shell Polymer/GNP/Fiber surface Auxetic honeycomb Shear connectors