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RELIABILITY ANALYSIS OF FRP LAMINATED PLATES WITh cONSIDERATION OF BOTh INITIAL IMPERFEcTION AND FAILURE SEQUENcE

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Acta Mechanica Solida Sinica 2002年第3期15卷 227-235页

作者： chen, JQ Wang, XY Luo, c huazhong Univ Sci & Technol Dept Mech Wuhan 430074 Peoples R China

A probabilistic progressive failure analyzing method is applied to estimating the reliability of a simply supported laminated composite plate with an initial imperfection under bi-axial compression load. The initial imperfection and the strength parameters are considered as random variables. Ply-level failure probability is evaluated by the first order reliability method (FORM) together with the Tsai-Wu strength criterion and Tan criterion. current stresses in the laminated structure are calculated by the classical lamination theory with the stiffness modified based on the last step ply failure. Probabilistically dominant ply-level failure sequences leading to overall system failure are identified, based on which the system failure probability is estimated. A numerical example is presented to demonstrate the methodology proposed. Through parameter studies it is shown that the deviation of the initial imperfection and some of the strength parameters largely influence the system reliability.

关键词： failure sequences initial imperfection laminated-plates structural reliability first order reliability method (FORM) strength criterion

Research of Neural Network Based on Improved PSO Algorithm for carbonation Depth Prediction of concrete

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武汉理工大学学报 2010年第17期32卷 170-175页

作者： DAI W ShUI Z h School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China School of Economics and Management Huangshi Institution of TechnologyHuangshi 435003China

Firstly,neural network based on improved particle swarm optimization (PSO)algorithm is introduced in this paper. Based on the data collected from projects in typical areas,the concrete carbonation depth is assessed with consideration of various factors such as unit cement consumption (c),unit water consumption (W),binder material content (B),water binder ratio (W/B ),concrete strength (MPa),rapid carbonization days (D),fly ash consumption of unit volume concrete(FA),fly ash percentage of total cementitious materials (FA%),expansion agent consumption of unit volume concrete(EA),expansion agent percentage of total cementitious materials (FA%).Gaining the data from project-experiment,a model is presented to calculate and forecast carbonation depth using neural network based on improved PSO algorithm. The calculation results indicate that this algorithm accord with the prediction carbonation depth of concrete accuracy requirements and has a better convergence and generalization,worth being popularized.

关键词： PSO BP neural network concrete carbonation depth prediction

Particulate Flow Simulation via a Boundary condition-Enforced Immersed Boundary-Lattice Boltzmann Scheme

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communications in computational Physics 2010年第4期7卷 793-812页

作者： J.Wu c.Shu Department of Mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260

A boundary condition-enforced immersed boundary-lattice Boltzmannmethod (IB-LBM) for the simulation of particulate flows is presented in this paper. Ingeneral, the immersed boundary method (IBM) utilizes a discrete set of force densityto represent the effect of boundary. In the conventional IB-LBM, such force density ispre-determined, which cannot guarantee exact satisfaction of non-slip boundary condition. In this study, the force density is transferred to the unknown velocity correctionwhich is determined by enforcing the non-slip boundary condition. For the particulateflows, accurate calculation of hydrodynamic force exerted on the boundary of particlesis of great importance as it controls the motion of particles. The capability of presentmethod for particulate flows is depicted by simulating migration of one particle in asimple shear flow and sedimentation of one particle in a box and two particles in achannel. The expected phenomena and numerical results are achieved. In addition,particle suspension in a 2D symmetric stenotic artery is also simulated.

关键词： Lattice Boltzmann method immersed boundary method non-slip boundary condition particulate flow two-dimensional

Evaluation of the diagnostic performance of a commercial molecular assay for the screening of suspected monkeypox cases in Sri Lanka

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Infectious Medicine 2023年第2期2卷 136-142页

作者： h.B.c.harshani G.A.Liyanage D.V.R.G.Ruwan U.K.I.U.Samaraweera J.I.Abeynayake Medical Research Institute Colombo 08Sri Lanka

Background:The main objective of the present study was to compare the diagnostic performance of the commercial LightMix Modular Monkeypox Virus(MPXV)qPcR(TIB Molbiol,Germany)assay with the in-house non-variola orthopox/monkeypox generic real-time PcR assay(IcMR-NIV,Pune)for the screening of(MPXV)cases at Medical Research Institute(MRI)in Sri ***,clinical and sociodemographic data of suspected/confirmed cases received at MRI for the MPXV screening were also ***:The diagnostic performance of the commercial LightMix Modular MPXV qPcR assay with the in-house nonvariola orthopox/monkeypox generic real-time PcR assay for the screening of suspected MXPV cases was evaluated using standard methods with minor ***-demographic and clinical profiles of suspected and confirmed MPXV cases were also ***:The commercial LightMix Modular MPXV assay was able to detect MPXV with 100%sensitivity and specificity with non-variola orthopox/monkeypox generic rtPcR *** the period of study,from the total of 25 samples tested,only 2 were MPXV-positive(males).The most common symptoms of suspected MPXV cases were lesions or rashes(92%).conclusions:With the continually increasing number of cases,access to MPXV testing should be made more widely *** commercial LightMix Modular MPXV(TIB Molbiol)qPcR assay offers comparable performance to the non-variola orthopox/monkeypox generic real time PcR assay for MPXV detection during the present outbreak.

关键词： Orthopoxvirus Monkeypox virus Real-time PcR assays Patient screening

Endoscopic ultrasound-guided techniques for diagnosing pancreatic mass lesions: can we do better?

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World Journal of Gastroenterology 2016年第39期22卷 8658-8669页

作者： Andrew c Storm Linda S Lee Division of Gastroenterology Hepatology and Endoscopy Brigham and Women’s Hospital Harvard Medical School

The diagnostic approach to a possible pancreatic mass lesion relies first upon various non-invasive imaging modalities, including computed tomography, ultrasound, and magnetic resonance imaging techniques. Once a suspect lesion has been identified, tissue acquisition for characterization of the lesion is often paramount in developing an individualized therapeutic approach. Given the high prevalence and mortality associated with pancreatic cancer, an ideal approach to diagnosing pancreatic mass lesions would be safe, highly sensitive, and reproducible across various practice settings. Tools, in addition to radiologic imaging, currently employed in the initial evaluation of a patient with a pancreatic mass lesion include serum tumor markers, endoscopic retrograde cholangiopancreatography, and endoscopic ultrasound-guided fine needle aspiration(EUS-FNA). EUS-FNA has grown to become the gold standard in tissue diagnosis of pancreatic lesions.

关键词： Endoscopic ultrasound Fine needle aspiration Pancreatic cancer Pancreatic mass Endoscopy

Suppression of a spontaneous dust density wave by modulation of ion streaming

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Plasma Science and Technology 2020年第4期22卷 40-47页

作者： Tonuj DEKA Bidyut chUTIA Y BAILUNG S K ShARMA h BAILUNG Physical Sciences Division Institute of Advanced Study in Science and Technology(IASST)Paschim BoragaonGarchukGuwahatiAssam 781035India

Synchronization of a self-excited dust density wave has been experimentally investigated in a strongly coupled dusty plasma.A dust density wave of frequency^78 hz is spontaneously generated from the dust void boundary due to the ion streaming *** electric field in the dust void region is measured,and the electric field force and ion drag force on the dust particles at the void boundary are estimated to explain the mechanism of spontaneous dust density wave *** occurring through the suppression mechanism is observed by modulating the ion streaming by applying an external sinusoidal signal to the dust *** sufficiently high modulation amplitude,the onset of period-doubling bifurcation is *** Fourier transform spectral analysis is done using time-series data obtained from high-speed video *** van der Pol equation with a force term is used to correlate the observed suppression phenomena.

关键词： dust density wave suppression phenomena strongly coupled dusty plasma forced van der Pol equation

TIME-INDEPENDENT ANISOTROPIc PLASTIc BEhAVIOR BY MEchANIcAL SUBELEMENT MODELS

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Applied Mathematics and Mechanics(English Edition) 1984年第4期5卷 1425-1435页

作者： Theodore h. h. Pian (Massachusetts Institute of Technology) Massachusetts Institute of Technology USA

The paper describes a procedure for modelling the anisotropic elastic-plastic behavior of metals in plane stress state by the mechanical sub-layer model. In this model the stress-strain curves along the longitudinal and transverse directions are represented by short smooth segments which are considered as piecewise linear for simplicity. The model is incorporated in a finite element analysis program which is based on the assumed stress hybrid element and the viscoplasticity theory.

关键词： TIME-INDEPENDENT ANISOTROPIc PLASTIc BEhAVIOR BY MEchANIcAL SUBELEMENT MODELS

The evolution of the atmosphere in the Archaean and early Proterozoic

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chinese Science Bulletin 2011年第1期56卷 4-13页

作者： NISBET Euan FOWLER c Mary R Deptartment of Earth Sciences Royal HollowayUniversity of London

Key steps in atmospheric evolution occurred in the *** hadean atmosphere was created by the inorganic processes of volatile accretion from space and degassing from the interior,and then modified by chemical and photochemical *** air was probably initially anoxic,though there may have been a supply of oxidation power as a consequence of hydrodynamic escape to space of hydrogen from *** subduction may have removed cO2 and the hadean planet may have been *** the Archaean,as anoxygenic and then oxygenic photosynthesis evolved,biological activity remade the *** evidence implies there were liquid oceans despite the faint young *** oceans may have been sustained by the greenhouse warming effect of biologically-made *** in the late Archaean would have released free O2 into the *** would have created oxic surface waters,challenging the methane *** the Great Oxidation Event around 2.3 to 2.4 billion years ago,the atmosphere itself became oxic,perhaps triggering a glacial crisis by cutting methane-caused greenhouse *** the early Proterozoic,all the key biochemical processes that maintain the modern atmosphere were probably present in the microbial community.

关键词：晚太古代大气演化早元古代二氧化碳温室效应光化学过程微生物群落调制解调器

Field-resolved high-order sub-cycle nonlinearities in a terahertz semiconductor laser

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Light(Science & Applications) 2021年第12期10卷 2531-2540页

作者： J.Riepl J.Raab P.Abajyan h.Nong J.R.Freeman L.h.Li E.h.Linfield A.G.Davies A.Wacker T.Albes c.Jirauschek c.Lange S.S.Dhillon R.huber Department of Physics University of RegensburgRegensburgGermany Laboratoire de Physique de l’Ecole Normale Supérieure ENSUniversitéPSLCNRSSorbonne UniversitéUniversitéde ParisParisFrance School of Electronic and Electrical Engineering University of LeedsWoodhouse LaneLeedsUK Mathematical Physics and NanoLund Lund UniversityLundSweden Department of Electrical and computer Engineering Technical University of MunichMunichGermany Department of Physics TU Dortmund UniversityDortmundGermany

The exploitation of ultrafast electron dynamics in quantum cascade lasers(QcLs)holds enormous potential for intense,compact mode-locked terahertz(Thz)sources,squeezed Thz light,frequency mixers,and comb-based metrology *** the important sub-cycle dynamics have been notoriously difficult to access in operational Thz ***,we employ high-field Thz pulses to perform the first ultrafast two-dimensional spectroscopy of a free-running Thz *** incoherent and coherent nonlinearities up to eight-wave mixing are detected below and above the laser *** data not only reveal extremely short gain recovery times of 2 ps at the laser threshold,they also reflect the nonlinear polarization dynamics of the QcL laser transition for the first time,where we quantify the corresponding dephasing times between 0.9 and 1.5 ps with increasing bias currents.A density-matrix approach reproducing the emergence of all nonlinearities and their ultrafast evolution,simultaneously,allows us to map the coherently induced trajectory of the Bloch *** observed high-order multi-wave mixing nonlinearities benefit from resonant enhancement in the absence of absorption losses and bear potential for a number of future applications,ranging from efficient intracavity frequency conversion,mode proliferation to passive mode locking.

关键词： polarization mixer cycle