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DCM染料激光激发下的HoP_5O_(14)非晶的上转换发光动力学
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作者 陈晓波 李美仙 +2 位作者 孟超 李晓文 宋增福 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2001年第2期139-141,共3页
本文研究了DCM染料激光激发下的HoP5 O1 4 非晶在 370~ 5 80nm兰绿波段的上转换发光的动力学过程 ,发现离子间能量传递上转换和步进双光子吸收两种机理都共同参与导致了它们的上转换发光 ,而激发光频率的稍微改变会使其上转换动力学发... 本文研究了DCM染料激光激发下的HoP5 O1 4 非晶在 370~ 5 80nm兰绿波段的上转换发光的动力学过程 ,发现离子间能量传递上转换和步进双光子吸收两种机理都共同参与导致了它们的上转换发光 ,而激发光频率的稍微改变会使其上转换动力学发生很大变化。 展开更多
关键词 HoP5O14非晶 转换发光动力学 DCM染料 激光激发 激光器
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铁路隧道十字交叉隔壁后拆式工法施工力学特性及其应用研究
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作者 林本涛 《铁道标准设计》 北大核心 2015年第12期58-63,共6页
厦(门)深(圳)铁路梁山隧道穿越L7富水软弱带使施工严重受阻。为确保隧道顺利通过L7富水软弱带,通过多种经济、技术比选,最终确定通过超前预加固措施改良地层条件后,采用十字交叉隔壁后拆式工法施工。阐述十字交叉隔壁后拆式工法的特点... 厦(门)深(圳)铁路梁山隧道穿越L7富水软弱带使施工严重受阻。为确保隧道顺利通过L7富水软弱带,通过多种经济、技术比选,最终确定通过超前预加固措施改良地层条件后,采用十字交叉隔壁后拆式工法施工。阐述十字交叉隔壁后拆式工法的特点及施工工序,同传统CRD工法相比,该工法的最大特点是:"后拆式"的十字交叉临时支撑体系,确保在临时支撑体系拆除时,初期支护和二次衬砌已经同时承载,避免传统工法中因拆撑时应力释放导致的初期支护结构失稳风险,确保施工过程中的安全可靠性。然后通过数值计算和力学分析方法,对十字交叉隔壁后拆式工法在施工过程中的支护力学转换体系进行详细分析,得出以下结论:初期支护与临时支撑组成的支护体系,在开挖的每一步中,都是承载的主体,尽可能早地闭合成环;二次衬砌的闭合时机就是二次衬砌的支护时间,以初期支护极限位移的60%作为施工二次衬砌的位移指导值较为合理。 展开更多
关键词 铁路隧道 十字交叉隔壁后拆式工法 L7深埋富水软弱带 施工力学体系转换
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聚焦钙钛矿光伏器件中慢速动力学机制研究进展
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作者 于嫚 《材料导报》 EI CAS CSCD 北大核心 2020年第15期15059-15062,共4页
利用光伏效应直接将太阳能转化为电能,是获取可持续清洁能源的重要途径之一。近年来,钙钛矿太阳能电池成为光伏领域的研究热点,随着结构调控和制备工艺的不断发展,目前其光电转换效率已经突破25%。虽然钙钛矿光伏器件具有制备条件温和... 利用光伏效应直接将太阳能转化为电能,是获取可持续清洁能源的重要途径之一。近年来,钙钛矿太阳能电池成为光伏领域的研究热点,随着结构调控和制备工艺的不断发展,目前其光电转换效率已经突破25%。虽然钙钛矿光伏器件具有制备条件温和、成本低、效率高等优点,但该类光伏器件呈现出秒量级甚至分钟量级的慢速动力学现象,这对钙钛矿光伏器件性能以及正确认识光电转换动力学造成较大的影响。迄今对慢速动力学的认识仍处于猜测阶段,尚缺乏系统认识。其中离子迁移和缺陷态属性被当作慢速动力学的主要研究目标。本文从钙钛矿光伏器件原初的电荷分离开始,分析了钙钛矿太阳能电池在多时间跨度内的载流子动力学行为;讨论了可能造成钙钛矿光伏器件慢速动力学的原因,认为可以从关键的钙钛矿活性层切入;揭示了钙钛矿活性层结构对慢速动力学的影响机理;为全新认识钙钛矿太阳能电池光电转换过程提供新思路,从而进一步指导器件设计和制备。 展开更多
关键词 钙钛矿太阳能电池 光电转换力学 载流子传输 载流子复合 慢速动力学
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IMPROVED ALGORITHM FOR CFD/CSD COUPLED SYSTEM DESIGN AND CALCULATION 被引量:4
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作者 安效民 徐敏 陈士橹 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2010年第2期162-169,共8页
The data information transfer and time marching strategies between computational fluid dynamics (CFD) and computational structural dynamics (CSD) play crucial roles on the aeroelastic analysis in a time domain. An... The data information transfer and time marching strategies between computational fluid dynamics (CFD) and computational structural dynamics (CSD) play crucial roles on the aeroelastic analysis in a time domain. An improved CFD/CSD coupled system is designed, including an interpolation method and an improved loosely coupled algorithm. The interpolation method based on boundary element method (BEM) is developed to transfer aerodynamic loads and structural displacements between CFD and CSD grid systems, it can be universally used in fluid structural interaction solution by keeping energy conservation. The improved loosely coupled algo-rithm is designed, thus it improves the computational accuracy and efficiency. The new interface is performed on the two-dimensional (2-D) extrapolation and the aeroelastie response of AGARD445.6 wing. Results show that the improved interface has a superior accuracy. 展开更多
关键词 computational fluid dynamics boundary element method data transfer fluid and structure interaction aeroelasticity
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桥梁深水基础钢板桩围堰设计与施工 被引量:6
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作者 刘媛 《建筑技术开发》 2014年第7期12-15,共4页
针对桥梁基础位于水库深水区,不宜采用双壁钢围堰施工,提出采用拉森钢板桩围堰施工方案。钢板桩围堰方案设计中,充分考虑各个施工阶段的受力特点和作业空间,设置不同形式的围堰内支撑,形成多次力学体系转换的钢围堰结构。钢板桩围堰力... 针对桥梁基础位于水库深水区,不宜采用双壁钢围堰施工,提出采用拉森钢板桩围堰施工方案。钢板桩围堰方案设计中,充分考虑各个施工阶段的受力特点和作业空间,设置不同形式的围堰内支撑,形成多次力学体系转换的钢围堰结构。钢板桩围堰力学分析采用两种途径完成,对钢板桩围堰的施工过程进行了动态仿真模拟。力学分析表明,钢板桩围堰整体稳定性、基底抗隆起稳定性、抗倾覆稳定性均满足规范安全要求,围堰结构的强度、变形满足规范要求。此外,采用多次力学体系变换的钢板桩围堰,符合施工过程的受力特征,应用于桥梁深水基础施工,可缩短工期,降低施工成本。 展开更多
关键词 桥梁工程 深水基础 钢板桩 钢围堰 力学体系转换 施工仿真分析
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Convolution Theorem of Fractional Fourier Transformation Derived by Representation Transformation in Quantum Mechancis 被引量:1
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作者 FAN Hong-Yi HAO Ren LU Hai-Liang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第9期611-614,共4页
Based on our previous paper (Commun.Theor.Phys.39 (2003) 417) we derive the convolution theoremof fractional Fourier transformation in the context of quantum mechanics,which seems a convenient and neat way.Generalizat... Based on our previous paper (Commun.Theor.Phys.39 (2003) 417) we derive the convolution theoremof fractional Fourier transformation in the context of quantum mechanics,which seems a convenient and neat way.Generalization of this method to the complex fractional Fourier transformation case is also possible. 展开更多
关键词 fractional Fourier transformation convolution theorem quantum mechanical representation transform
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Thermodynamic Modeling of Wax Precipitation in Crude Oils 被引量:3
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作者 陈五花 赵宗昌 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2006年第5期685-689,共5页
Most of the crude oils contain waxes which precipitate when temperature drops, resulting in deposition in pipelines and production equipment. It is necessary to set up a model which can predict the wax appearance tem-... Most of the crude oils contain waxes which precipitate when temperature drops, resulting in deposition in pipelines and production equipment. It is necessary to set up a model which can predict the wax appearance tem-perature and the amount of solid precipitated in the different conditions. A modified thermodynamic solid-liquid equilibrium model to calculate wax precipitation in crude oil systems has been developed recently. The assumption that precipitated waxes consist of several solid phases is adopted in this research, and the solid-solid transition is also considered in the modified model. The properties of the pseudo-components are determined by using empirical correlations. New correlations for properties of solid-solid and solid-liquid transitions are also established in this work on the basis of the data from the literature. The results predicted by the proposed model for three crude oil systems are compared with the experimental data and the calculated results from the literature, and good agreement is observed. 展开更多
关键词 waxy crude oil solid-solid transition solid-liquid equilibrium thermodynamic model wax precipitation
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Static corrections for low S/N ratio converted-wave seismic data 被引量:2
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作者 Li Guofa Peng Suping 《Applied Geophysics》 SCIE CSCD 2008年第1期44-49,共6页
Converted waves have slow velocity and low signal-to-noise ratio. It is also difficult to pick first-breaks and bin the common-conversion-points (CCP). Some statics methods, which work well for P-wave data, can't b... Converted waves have slow velocity and low signal-to-noise ratio. It is also difficult to pick first-breaks and bin the common-conversion-points (CCP). Some statics methods, which work well for P-wave data, can't be effectively used for solving convertedwave statics problems. This has become the main obstacle to breakthroughs in convertedwave data processing. To improve converted-wave static corrections, first, a statics method based on the common-receiver-point (CRP) stack is used for the initial receiver static correction to enhance the coherency of the CRP stack. Second, a stack-power-maximization static correction which improves the continuity of the CCP stack is used for detailed receiver statics. Finally, a non-surface-consistent residual moveout correction of the CCP gathers is used to enhance the stack power of reflection signals from different depths. Converted-wave statics are solved by the joint use of the three correction methods. 展开更多
关键词 converted-wave STATICS common-receiver-point stack stack-power-maximization non-surface-consistent.
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Parseval Theory of Complex Wavelet Transform for Wavelet Family Including Rotational Parameters 被引量:1
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作者 ZHOU Nan-Run JIA Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第9期598-602,共5页
A rotational parameter Rθ has been introduced to complex wavelet transform (CWT). The rotational CWT (RCWT) corresponds to a matrix element 〈φ|U2(θ;μ;κ)[F〉 in the context of quantum mechanics, where U2(... A rotational parameter Rθ has been introduced to complex wavelet transform (CWT). The rotational CWT (RCWT) corresponds to a matrix element 〈φ|U2(θ;μ;κ)[F〉 in the context of quantum mechanics, where U2(θ;μ;κ) is a two-mode rotational displacing-squeezing operator in the 〈η| representation. Based on this, the Parseval theorem and the inversion formula of RCWT have been proved. The concise proof not only manifestly shows the merit of Dirac's representation theory but also leads to a new orthogonal property of complex mother wavelets in parameter space. 展开更多
关键词 complex wavelet transform representation theory quantum mechanics
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Theoretical Studies of Electron Paramagnetic Resonance Parameters for Cr^4+ Ions in Ca2GeO4 Crystals
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作者 WUXiao-Xuan ZHENGWen-Chen MEIYang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期337-340,共4页
The electron paramagnetic resonance (EPR) parameters (zero-Geld splitting Dand g factors g_‖, g_⊥) of Cr~(4+) ions in Ca_2 GeO_4 crystals have been calculated from thecomplete high-order perturbation formulas of EPR... The electron paramagnetic resonance (EPR) parameters (zero-Geld splitting Dand g factors g_‖, g_⊥) of Cr~(4+) ions in Ca_2 GeO_4 crystals have been calculated from thecomplete high-order perturbation formulas of EPR parameters for a 3d~2 ion in trigonal MX_4clusters. In these formulas, in addition to the contributions to EPR parameters from the widely usedcrystal-field (CF) mechanism, the contributions from the charge-transfer (CT) mechanism (which areoften neglected) are included. From the calculations, it is found that for the high valence state3d~n ions in crystals, the reasonable explanation of EPR parameters (in particular, the g factors)should take both the CF and CT mechanisms into account. 展开更多
关键词 crystal- and ligand-field theory electron paramagnetic resonance charge-transfer mechanism optical spectroscopy tunable laser crystal
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General Formalism for Setting Up Unitary Transform Operators from Classical Transforms via IWOP Technique
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作者 FAN Hong-Yi HU Shan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第1X期55-57,共3页
We present a general formalism for setting up unitary transform operators from classical transforms via the technique of integration within an ordered product of operators, their normally ordered form can be obtained ... We present a general formalism for setting up unitary transform operators from classical transforms via the technique of integration within an ordered product of operators, their normally ordered form can be obtained too. 展开更多
关键词 IWOP technique correspondence between classic and quantum mechanical version
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Quantum Optical Squeezing Transform for Generalizing Fractional Fourier Transform
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作者 HU Li-Yun FAN Hong-Yi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第10期951-954,共4页
By establishing the relation between the optical scaled fractional Fourier transform (FFT) and quantum mechanical squeezing-rotating operator transform, we employ the bipartite entangled state representation of two-... By establishing the relation between the optical scaled fractional Fourier transform (FFT) and quantum mechanical squeezing-rotating operator transform, we employ the bipartite entangled state representation of two-mode squeezing operator to extend the scaled FFT to more general cases, such as scaled complex FFT and entangled scaled FFT. The additiyity and eigenmodes are presented in quantum version. The relation between the scaled FFT and squeezing-rotating Wigner operator is studied. 展开更多
关键词 squeezing transform scaled fractional Fourier transform IOWP technique
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Reaction pathway and kinetics of CdO nanoparticles prepared from CdCO_3 precursor using thermal decomposition method
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作者 Gholam Reza KHAYATI Seyed Hadi SHAHCHERAGHI +1 位作者 Vahid LOTFI Esmael DAREZARESHKI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第4期1138-1145,共8页
The non-isothermal kinetics of CdO nanoparticles prepared from CdCO3 precursor using thermal decomposition method was investigated. A model-fitting Malek approach and a model-free advanced isoconversional method of Vy... The non-isothermal kinetics of CdO nanoparticles prepared from CdCO3 precursor using thermal decomposition method was investigated. A model-fitting Malek approach and a model-free advanced isoconversional method of Vyazovkin were applied to the analysis of the DSC and TGA data. The results showed that CdO nanoparticles prepared from CdCO3 followed an autocatalytic reaction. Sestak–Berggren model could favorably describe the studied reaction process. Moreover, the apparent activation energy of CdCO3 decomposition was calculated to be (119.19±9.97) kJ/mol and the explicit rate equation form of CdCO3 decomposition was established. 展开更多
关键词 CdCO_3 CdO nanoparticle kinetic modeling thermal decomposition advanced isoconversional method
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How the Orbital System of Particles Consolidates Gravity and Electromagnetism
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作者 William Day 《Journal of Philosophy Study》 2012年第9期619-630,共12页
There is an actual reality that underlies the relative reality of physics. The orbital system is shown to be the principle by which motion transforms space into matter. The support of the universe is the absolute thre... There is an actual reality that underlies the relative reality of physics. The orbital system is shown to be the principle by which motion transforms space into matter. The support of the universe is the absolute three-stage hierarchy of particles, atoms, and gravitational systems. Below 1/c waves are dissociated into strands and neutrinos are separated as points of charge. The electron and positron are single strands with opposed helical turns. Protons and neutrons have a nucleus of positrinos and negatrinos surrounded by concentric shells of strands in 2"~ resonance. The orbital strands reverberate into space creating a field with gravitational and electromagnetic aspects. The orbital system defines matter, energy, motion, and time based on composition. The three stages have a constant field content but differ by field density and components. 展开更多
关键词 orbital systems GRAVITY electromagnetism STRANDS NEUTRINOS positrino negatrino proton compositionspace matrix
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Numerical Study of Thermoelectric Generation within a Reciprocal Flow Porous Media Burner
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作者 Luis Henrlquez-Vargas Pablo Donoso 《Journal of Mechanics Engineering and Automation》 2013年第6期367-377,共11页
A numerical study based on direct thermal to electric energy conversion was performed in a reciprocal flow porous media burner embedded with two layers of thermoelements. The burner lean combustibility limit was sough... A numerical study based on direct thermal to electric energy conversion was performed in a reciprocal flow porous media burner embedded with two layers of thermoelements. The burner lean combustibility limit was sought in order to maximize global efficiency of thermal to electrical energy conversion by minimizing fuel consumption. Once the pairs of operational variables, composition and filtrational velocity of gas inlet mixture were found, the optimal length and placement of thermoelectric elements within the reactor high thermal gradients were sought to maximize the electric current, thermoelements and system overall efficiency. A two temperature-resistance model for finite time thermodynamics was developed for the thermoelectric elements energy fluxes. Results indicate a distribution of current and efficiencies that presents a maximum at different themoelements length. Maximum values for current and system efficiency obtained were 44.3 m A and 2.5%, respectively. 展开更多
关键词 COMBUSTION Porous media thermoelectric generation.
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Exact Solution to (1+1)-Dimensional Higher-Order Schrodinger Equation via an Extended Mapping Approach
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作者 ZHU Hai-Ping ZHENG Chun-Long FANG Jian-Ping 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第1期127-130,共4页
Starting from a special variable transformation and with the help of an extended mapping approach, the high-order Schrodinger equation (n = 3, 4) is solved. A new family of variable separation solutions with arbitra... Starting from a special variable transformation and with the help of an extended mapping approach, the high-order Schrodinger equation (n = 3, 4) is solved. A new family of variable separation solutions with arbitrary functions is derived. 展开更多
关键词 extended mapping approach Schrodinger equation exact solution
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Super-exchange and Exchange-Enhanced Reactivity in Fe_(4)S_(4)-Mediated Activation of SAM by Radical SAM Enzymes
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作者 Jian-qiang Feng Bin-ju Wang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2021年第5期532-540,I0002,共10页
[4Fe-4S]-dependent radical S-adenosylmethionine(SAM)proteins are a superfamily of oxidoreductases that can catalyze a series of challenging transformations using the common 5-d Ado radical intermediate.Although the st... [4Fe-4S]-dependent radical S-adenosylmethionine(SAM)proteins are a superfamily of oxidoreductases that can catalyze a series of challenging transformations using the common 5-d Ado radical intermediate.Although the structures and functions of radical SAM enzymes have been extensively studied,the electronic state-dependent reactions of the[4Fe-4S]clusters in these enzymes are still elusive.Herein we performed QM/MM calculations to elucidate the electronic state-dependent reactivity of the[4Fe-4S]cluster in pyruvate-formate lyase activating enzyme.Our calculations show that the electronic statedependent SAM activation by the[4Fe-4S]clusters in radical SAM enzyme is determined by both the super-exchange and exchange-enhanced reactivities.The super-exchange coupling in the[4Fe-4S]cluster favors the antiferromagnetic coupling between two neighbouring pairs,which results in theα-electron rather than theβ-electron donation from the[4Fe-4S]^(1+)cluster toward the SAM activation.Meanwhile,in the most favorable electronic state for the reductive cleavage of S-C5′,Fe4 would donate itsα-electron to gain the maximum exchange interactions in the Fe4-block.Such super-exchange and exchange-enhanced reactivity could be the general principles for reactivities of[4Fe-4S]cluster in RS enzymes. 展开更多
关键词 QM/MM Iron-sulfur protein Electron transfer Super-exchange Exchange-enhanced reactivity Radical SAM enzyme
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基于结构概念分析法的洞桩法密贴下穿既有地铁站施工力学研究 被引量:6
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作者 赵伟 《铁道建筑技术》 2021年第11期9-12,17,共5页
根据基础力学理论与工程实际相结合的思想,采用结构概念分析的方法,研究了洞桩法密贴下穿既有地铁车站施工过程的力学特性及其关键控制环节。结果表明:结构概念分析法将土层简化为梁、柱或桁架的杆系模型,可以对下穿过程力学转换进行定... 根据基础力学理论与工程实际相结合的思想,采用结构概念分析的方法,研究了洞桩法密贴下穿既有地铁车站施工过程的力学特性及其关键控制环节。结果表明:结构概念分析法将土层简化为梁、柱或桁架的杆系模型,可以对下穿过程力学转换进行定性分析,用于指导地下工程施工;土层和支护结构的刚度设计是调整应力分配方向、降低群洞效应和控制变形的决定性因素;隧道下穿施工风险主要是开挖和支护过程的转换阶段,而非最终状态,应重视对施工过程中力学状态的判断。 展开更多
关键词 地下结构 洞桩法 密贴下穿 力学转换
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斜拉桥施工仿真 被引量:6
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作者 张海龙 刘昌国 +2 位作者 段凯 王丽新 苏砺锋 《公路》 北大核心 2003年第8期72-75,共4页
斜拉桥的施工是一项极其复杂的力学体系转换过程 ,必须进行施工监控。目前的施工监控是采用平面杆系的有限元法。针对仙桃汉江大桥 ,利用块体等空间单元 ,按照施工的真实步骤 ,逼真地建立了该斜拉桥一系列的空间计算模型。使得设计和监... 斜拉桥的施工是一项极其复杂的力学体系转换过程 ,必须进行施工监控。目前的施工监控是采用平面杆系的有限元法。针对仙桃汉江大桥 ,利用块体等空间单元 ,按照施工的真实步骤 ,逼真地建立了该斜拉桥一系列的空间计算模型。使得设计和监控更加逼近真实状态 。 展开更多
关键词 斜拉桥 施工监控 施工仿真 力学体系转换 空间计算模型 计算机技术
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锚索假定失效状态下的悬索桥岩锚安全储备研究
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作者 汤庆超 张隆顺 +1 位作者 廖贵彩 余波 《公路》 北大核心 2022年第10期175-178,共4页
岩锚是悬索桥锚碇的一种结构形式。受制于地形、地质及结构耐久性等影响因素,岩锚相对于重力式锚碇及隧道式锚碇,其应用范围较小。为克服锚索受制因素,以实际工程为案例,采用定性与定量相结合的方式,研究岩锚在假定部分锚索失效情况下... 岩锚是悬索桥锚碇的一种结构形式。受制于地形、地质及结构耐久性等影响因素,岩锚相对于重力式锚碇及隧道式锚碇,其应用范围较小。为克服锚索受制因素,以实际工程为案例,采用定性与定量相结合的方式,研究岩锚在假定部分锚索失效情况下的安全补偿机制,通过利用岩锚在特定状态下的力学转换系统,弥补部分锚索因失效而损失的抗力,从而提高桥梁结构的安全储备。 展开更多
关键词 悬索桥 锚碇 岩锚 安全储备 失效机理 力学转换系统
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