检索结果-南通市图书馆

Analysis of foundation sliding of an arch dam considering the hydromechanical behavior

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2012年第1期6卷 35-43页

作者： Maria Luísa Braga FARINHA JoséVieira de LEMOS Emanuel MARANHA DAS NEVES LNEC-National Laboratory for Civil Engineering Av.Brasil 101Lisboa 1700-066Portugal ISt-instituto superior técnico Av.Rovisco Pais 1Lisboa 1049-001Portugal

this paper presents the application of a methodology which can be used to assess arch dam foundation stability,using the discrete element method(DEM)and the code 3DEC.A global three-dimensional model of a dam foundation was developed,in which some discontinuities were simulated and both the grout and drainage curtains were *** model,calibrated taking into account recorded data,was used to carry out nonlinear mechanical *** same model was employed to perform a hydraulic analysis,based on equivalent continuum concepts,which allowed the water pressure pattern within the foundation to be *** water pressures were applied on discontinuities involved in the possible sliding mechanism along the dam/foundation interface,and the safety of the dam/foundation system was evaluated using a process of reduction of strength characteristics,with the aim of calculating the minimum safety factors that ensure *** were compared with those obtained with the usual bi-linear uplift pressure distribution at the base of the dam,commonly used in concrete dam *** relevance of carrying out hydraulic analysis in arch dam foundation failure studies is highlighted.

关键词： concrete dams rock foundations hydromechanical behavior failure 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

海上液化天然气行业风险分析研究综述

哈尔滨工程大学学报（英文版） 2023年第4期22卷 693-715页

作者： Mohamed Abdelmalek C.Guedes Soares Centre for Marine technology and Ocean Engineering(CENtEC) Instituto Superior TécnicoUniversidade de Lisboa Portugal

this research presents a review and classification of the published work related to applied risk analysis and risk management in the maritime liquefied natural gas(LNG)sector from 2000 to *** papers are categorised under two primary *** first is the risk analysis theory context which represents the classification with respect to(w.r.t.)the used risk analysis method,the used risk analysis tool,and the objective of risk analysis,whereas the second is the presented case in the risk analysis context which represents the classification *** analysed LNG ship type,the analysed operation,and the inclusion level of human error in risk *** above process has revealed that the interest in this domain of research has increased significantly during the past *** addition,the use of dynamic risk analysis(DRA)tools,and the inclusion of human error in the risk analysis model have been observed significantly in the past five years,in particular,for modelling the risk of external LNG transfer *** is concluded that the inclusion of the effect of human and organisational factors(HOFs)in risk analysis,and the use of DRA methods for modelling the risk of the daily routine operations of the complex maritime LNG systems can improve the management of the operational risk of these systems.

关键词： Maritime LNG sector LNG hazards Risk analysis and management Human and organisational factors

Morphological and biochemical effects of weekend alcohol consumption in rats: Role of concentration and gender

在线全文

学校读者我要写书评

暂无评论

World Journal of Hepatology 2018年第2期10卷 297-307页

作者： José A Morales-González María de Lourdes Sernas-Morales ángel Morales-González Laura Ligía González-López Eduardo Osiris Madrigal-Santillán Nancy Vargas-Mendoza tomás Alejandro Fregoso-Aguilar Liliana Anguiano-Robledo Eduardo Madrigal-Bujaidar Isela álvarez-González Germán Chamorro-Cevallos Laboratorio de Medicina de Conservación Escuela Superior de Medicina Instituto Politécnico Nacional Escuela superior de Cómputo Instituto Politécnico Nacional área Académica de Nutrición ICSa Universidad Autónoma del Estado de Hidalgo Depto. de Fisiología Laboratorio de Hormonas y Conducta ENCB campus Zacatenco Instituto Politécnico Nacional Laboratorio de Farmacología Molecular Sección de Estudios de Posgrado e Investigación Escuela Superior de Medicina-Instituto Politécnico Nacional Laboratorio de Genética Escuela Nacional de Ciencias Biológicas IPN Departamento de Farmacia Escuela Nacional de Ciencias Biológicas Instituto Politécnico Nacional

AIM to examine the association between weekend alcohol consumption and the biochemical and histological alterations at two different concentrations of alcohol in both genders in *** Wistar rats weighing 170-200 g were divided into groups as follows:(1) Control groups; and(2) weekend alcohol-consumption group: 2 d/weekly per 12 wk, at two different concentrations:(1) Group of males or females with a consumption of a solution of alcohol at 40%; and(2) group of males or females with a consumption of a solution of alcohol at 5%. At the end of the experiment, serum and liver samples were obtained. the following enzymes and metabolites were determined in serum: Alanine Aminotransferase(ALt), Aspartate Aminotransferase(ASt), Lactate Dehydrogenase, and Gamma-Glutamyltransferase, and glucose, triglycerides, cholesterol, bilirubin, and albumin. Liver samples from each group were employed to analyze morphological abnormalities by light *** In all of the weekend alcohol-consumption groups, ASt activity presented a significant, 10-fold rise. Regarding ALt activity, the groups with weekend alcohol consumption presented a significant increase that was six times greater. Bilirubin levels increased significantly in both groups of females. We observed a significant increase in the parameters of fatty change and inflammation due to weekend alcohol consumption. Only the group of females that consumed alcohol at 40% presented slight hepatocel ular disorganization CONCLUSION the results obtained herein provide solid evidence that weekend alcohol consumption gives rise to liver damage, demonstrated by biochemical and histological alterations, first manifested acutely, and prolonged weekend alcohol consumption can cause greater, irreversible damage.

关键词： Weekend alcohol consumption Liver morphology transaminases Damage

Quantum teleportation and information splitting via four-qubit cluster state and a Bell state

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2017年第5期12卷 171-179页

作者： Marlon David González Ramirez Babatunde James Falaye Guo-Hua Sun M. Cruz-Irisson Shi-Hai Dong ESIME-Culhuaean Instituto Politécnico Nacional Av. Santa Ana 1000 Mexico CDMX 04430 Mexico Departamento de Fisica Escuela Superior de Fisica y Matemdticas Instituto Politécnico Nacional Edificio 9 UPALM CDMX 07738 Mexico Applied theoretical Physics Division Department of Physics Federal University Lafia P. M. B. 146 LafiaNigeria Catedrdtica CONACyt CIC Instituto Politéenico Nacional UPALM CDMX 07700 Mexico Laboratorio de Información Cudntica CIDETEC Instituto Politécnico Nacional UPALM CDMX 07700Mexico

Quantum teleportation provides a ＂bodiless＂ way of transmitting the quantum state from one object to another, at a distant location, using a classical communication channel and a previously shared entangled state. In this paper, we present a tripartite scheme for probabilistic teleportation of an arbitrary single qubit state, without losing the information of the state being teleported, via a fourqubit cluster state of the form ｜Ф） 1234 = α｜10000）＋β｜1010）＋ γ｜0101） - η｜1111）, as the quantum channel, where the nonzero real numbers α, β, γ, and η satisfy the relation ｜α｜^2 ＋｜β｜^2 ＋｜γ｜^2 ＋｜η｜^2 = 1. With the introduction of an auxiliary qubit with state ｜0}, using a suitable unitary transformation and a positive-operator valued measure （POVM）, the receiver can recreate the state of the original qubit. An important advantage of the teleportation scheme demonstrated here is that, if the teleportation fails, it can be repeated without teleporting copies of the unknown quantum state, if the concerned parties share another pair of entangled qubit. We also present a protocol for quantum information splitting of an arbitrary two-particle system via the aforementioned cluster state and a Bell-state as the quantum channel. Problems related to security attacks were examined for both the cases and it was found that this protocol is secure. this protocol is highly efficient and easy to implement.

关键词： teleportation positive-operator valued measure tripartite scheme security attacks

^(222)Rn calibration procedure for water analyses by liquid scintillation counting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

辐射探测技术与方法(英文) 2023年第2期7卷 311-319页

作者： Ana Rita Gomes Sérgio Dias Anabela Mourato Joao Abrantes Mário Reis Laboratório de Protecao e Seguranca Radiológica Instituto Superior TécnicoUniversidade de LisboaEstrada Nacional 10km 13972695‑066 Bobadela LRSPortugal Laboratórios de Massa e Massa Volúmica de Sólidos Instituto Portugues da QualidadeRua António Giao22829‑513 CaparicaPortugal Centro de Ciências e tecnologias Nucleares Instituto Superior TécnicoUniversidade de LisboaEstrada Nacional 10km 13972695‑066 Bobadela LRSPortugal

Purpose Among the several methods to measure ^(222)Rn in water,the liquid scintillation counting(LSC)technique is one of the most sensitive and widely used when analysing non-saline waters by liquid extraction,providing excellent accuracy,precision and low-level detection *** using the liquid scintillation counter tri-Carb 3170 tR/SL(Perkin-Elmer)it is not possible to make an automatic determination of the alpha/beta discrimination parameter,being necessary to evaluate the pulse decay discriminator(PDD)value manually to the ^(222)Rn *** this work,we describe the steps to perform the calibration of that type of *** the method consists in the preparation of standard samples from a ^(226)Ra certified standard solution and the adjustment of the PDD value by hand until the percentage of alpha events reaches a plateau of a near-constant fraction of total *** process consists in taking several measures between PDD 80 and 200 with 15 min counting time *** the plateau,the alpha/beta ratio was used to determine the plateau final range as well as the optimum PDD *** that,the calibration standards and blanks were measured and the region of interest(ROI)was established by finding the maximum value for the figure of merit(FOM)in the upper and lower *** the optimal PDD value of 148 was established by the alpha/beta ratio,and after that,it was possible to measure ^(226)Ra standards to perform the *** efficiency of(9.758±0.035)×1^(0-1) was *** routine measurements,a detection limit of about 0.50 Bq L^(-1) is achieved for a 120 min counting *** evaluate the uncertainty budget,the uncertainties of the net count rate,the efficiency,the sample amount and the decay correction factor were *** A method was developed for the calibration of LSC tri-Carb 3170 tR/SL with the optimization of the PDD using a ^(226)Ra standard *** acquisition to obtain the plot of the variation

关键词： Radon Waters Pulse decay discriminator Liquid scintillation counting Calibration

Photonics of time-varying media

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advanced Photonics 2022年第1期4卷 30-61页

作者： Emanuele Galiffi Romain tirole Shixiong Yin Huanan Li Stefano Vezzoli Paloma A.Huidobro Mário G.Silveirinha Riccardo Sapienza Andrea Alù J.B.Pendry City University of New York Photonics InitiativeAdvanced Science Research CenterNew YorkUnited States Imperial College London Blackett LaboratoryDepartment of PhysicsLondonUnited Kingdom Nankai University School of PhysicsTianjinChina instituto de telecomunicações Instituto Superior Técnico-University of LisbonLisboaPortugal City University of New York Physics ProgramGraduate CenterNew YorkUnited States

time-varying media have recently emerged as a new paradigm for wave manipulation,due to the synergy between the discovery of highly nonlinear materials,such as epsilon-near-zero materials,and the quest for wave applications,such as magnet-free nonreciprocity,multimode light shaping,and ultrafast *** this review,we provide a comprehensive discussion of the recent progress achieved with photonic metamaterials whose properties stem from their modulation in *** review the basic concepts underpinning temporal switching and its relation with spatial scattering and deploy the resulting insight to review photonic time-crystals and their emergent research avenues,such as topological and non-Hermitian *** then extend our discussion to account for spatiotemporal modulation and its applications to nonreciprocity,synthetic motion,giant anisotropy,amplification,and many other ***,we conclude with a review of the most attractive experimental avenues recently demonstrated and provide a few perspectives on emerging trends for future implementations of time-modulation in photonics.

关键词： time-varying media temporal modulation metamaterials switching optics photonics light

Improvement of the Mass Spectrometry Process on an Ion Implantation

在线全文

学校读者我要写书评

暂无评论

Open Journal of Optimization 2016年第1期5卷 31-34页

作者： José Lopes Jorge Rocha Luís Redondo Francisco Alegria instituto superior de Engenharia de Lisboa Rua Conselheiro Emídio Navarro Lisbon Portugal instituto de Plasmas e Fusão Nuclear Instituto Superior Técnico Universidade de Lisboa Lisbon Portugal instituto superior técnico and instituto de telecomunicações Lisbon Portugal

Mass spectrometry is an essential part of ion implantation. therefore, in order to guarantee beam purity avoiding contamination of the implanted samples, a system was developed for the high current implanter at the Laboratory of Accelerators and Radiation technologies (LAtR) at the instituto superior técnico. the system presented and discussed in this paper was developed using a LabVIEW code and uses a PC to control and display the mass spectrum. It also permits to save all data acquired for posterior analysis. In order to show some capabilities of this system, some experimental results are presented.

关键词： Ion Implanter LabVIEW Mass Spectrum

海上自主水面船舶(MASS)路径跟踪控制系统综述

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

哈尔滨工程大学学报（英文版） 2023年第2期22卷 153-171页

作者： Haitong Xu C.Guedes Soares Centre for Marine technology and Ocean Engineering(CENtEC) Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal

A review presents the state-of-the-art path-following control systems for maritime autonomous surface ships,where the special focus is placed on the guidance subsystem and control *** path following control system is one of the basic requirements for autonomous ships since it guarantees that the ship can track the predefined path with small crosstrack *** path following problem is firstly defined,and the cross-track error dynamics are derived from the kinematic equations of marine surface *** classical guidance laws are introduced,and the governing equations are also presented in this paper.A review of the guidance laws and controllers for the maritime autonomous surface ships has been carried out based on relevant journal and conference *** important properties and characteristics,such as control structure,guidance law,control method,stability,environmental disturbance and vessel dynamics,are defined for the comparative ***,the summary and a discussion on the most used technologies for the path following control of marine autonomous surface ships are presented and highlighted.

关键词： Maritime autonomous surface ship Path following Guidance law Control method Stability

Influence of Support Conditions on the Hydroelastic Behaviour of Floating thick Elastic Plate

在线全文

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2019年第3期18卷 295-313页

作者： K.M.Praveen D.Karmakar C.Guedes Soares Department of Applied Mechanics and Hydraulics National Institute of Technology KarnatakaSurathkalMangalore 575025India Centre for Marine technology and Ocean Engineering (CENtEC) Instituto Superior TécnicoUniversidade de LisboaAv. Rovisco Pais1049 001 LisbonPortugal

the hydroelastic response of very large floating structures (VLFS) under the action of ocean waves is analysed considering the small amplitude wave theory. the very large floating structure is modelled as a floating thick elastic plate based on timoshenko- Mindlin plate theory, and the analysis for the hydroelastic response is performed considering different edge boundary conditions. the numerical study is performed to analyse the wave reflection and transmission characteristics of the floating plate under the influence of different support conditions using eigenfunction expansion method along with the orthogonal mode-coupling relation in the case of finite water depth. Further, the analysis is extended for shallow water depth, and the continuity of energy and mass flux is applied along the edges of the plate to obtain the solution for the problem. the hydroelastic behaviour in terms of reflection and transmission coefficients, plate deflection, strain, bending moment and shear force of the floating thick elastic plate with support conditions is analysed and compared for finite and shallow water depth. the study reveals an interesting aspect in the analysis of thick floating elastic plate with support condition due to the presence of the rotary inertia and transverse shear deformation. the present study will be helpful for the design and analysis of the VLFS in the case of finite and shallow water depth.

关键词： timoshenko-Mindlin plate theory Very large floating structure Support condition Rotary inertia transverse shear deformation