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Effect of Doppler Shifts on Photon and Particle Flux of Beams 预览
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作者 Samuel Lewis Reich 《高能物理(英文)》 2019年第4期995-998,共4页
Reasons are given for a Doppler shift on the number of observed (sensed) photons in a light beam not just a shift in frequency, also a similar (non-relativistic) effect on the number of observed (sensed) particles (wi... Reasons are given for a Doppler shift on the number of observed (sensed) photons in a light beam not just a shift in frequency, also a similar (non-relativistic) effect on the number of observed (sensed) particles (with non-zero rest mass) in a particle beam. Optics texts have neither effect. 展开更多
关键词 PHOTON FLUX BEAMS INTENSITY IRRADIANCE PARTICLE FLUX
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Predicting the response of continuous RC deep beams under varying levels of differential settlement
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作者 M.Z.NASER R.A.HAWILEH 《结构与土木工程前沿:英文版》 EI CSCD 2019年第3期686-700,共15页
This paper investigates the effect of differential support settlement on shear strength and behavior of continuous reinforced concrete(RC)deep beams.A total of twenty three-dimensional nonlinear finite element models ... This paper investigates the effect of differential support settlement on shear strength and behavior of continuous reinforced concrete(RC)deep beams.A total of twenty three-dimensional nonlinear finite element models were developed taking into account various constitutive laws for concrete material in compression(crushing)and tension(cracking),steel plasticity(i.e.,yielding and strain hardening),bond-slip at the concrete and steel reinforcement interface as well as unique behavior of spring-like support elements.These models are first validated by comparing numerical predictions in terms of load-deflection response,crack propagation,reaction distribution,and failure mode against that of measured experimental data reported in literature.Once the developed models were successfully validated,a parametric study was designed and performed.This parametric study examined number of critical parameters such as ratio and spacing of the longitudinal and vertical reinforcement,compressive and tensile strength of concrete,as well as degree(stiffness)and location of support stiffness to induce varying levels of differential settlement.This study also aims at presenting a numerical approach using finite element simulation,supplemented with coherent assumptions,such that engineers,practitioners,and researchers can carry out simple,but yet effective and realistic analysis of RC structural members undergoing differential settlements due to variety of load actions. 展开更多
关键词 concrete CONTINUOUS BEAMS DEEP BEAMS FINITE element modeling support SETTLEMENT
Testing of a Full-Scale Composite Floor Plate 预览
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作者 Dennis Lam Xianghe Dai Therese Sheehan 《工程(英文)》 2019年第2期223-233,共11页
A full-scale composite floor plate was tested to investigate the flexural behavior and in-plane effects of the floor slab in a grillage of composite beams that reduces the tendency for longitudinal splitting of the co... A full-scale composite floor plate was tested to investigate the flexural behavior and in-plane effects of the floor slab in a grillage of composite beams that reduces the tendency for longitudinal splitting of the concrete slab along the line of the primary beams. This is important in cases where the steel decking is discontinuous when it is orientated parallel to the beams. In this case, it is important to demonstrate that the amount of transverse reinforcement required to transfer local forces from the shear connectors can be reduced relative to the requirements of Eurocode 4. The mechanism under study involved in-plane compression forces being developed in the slab due to the restraining action of the floor plate, which was held in position by the peripheral composite beams;while the secondary beams acted as transverse ties to resist the forces in the floor plate that would otherwise lead to splitting of the slab along the line of the primary beams. The tendency for cracking along the center line of the primary beam and at the peripheral beams was closely monitored. This is the first large floor plate test that has been carried out under laboratory conditions since the Cardington tests in the early 1990s, although those tests were not carried out to failure. This floor plate test was designed so that the longitudinal force transferred by the primary beams was relatively high (i.e., it was designed for full shear connection), but the transverse reinforcement was taken as the minimum of 0.2% of the concrete area. The test confirmed that the primary beams reached their plastic bending resistance despite the discontinuous decking and transverse reinforcement at the minimum percentage given in Eurocode 4. Based on this test, a reduction factor due to shear connectors at edge beams without U-bars is proposed. 展开更多
关键词 Floor plate test COMPOSITE BEAMS Edge BEAMS EUROCODE 4 IN-PLANE effect Column removal ROBUSTNESS
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An R(x)-orthonormal theory for the vibration performance of a non-smooth symmetric composite beam with complex interface 预览
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作者 Chein-Shan Liu Bo-Tong Li 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第1期228-241,I0007共15页
A composite beam is symmetric if both the material property and support are symmetric with respect to the middle point. In order to study the free vibration performance of the symmetric composite beams with different ... A composite beam is symmetric if both the material property and support are symmetric with respect to the middle point. In order to study the free vibration performance of the symmetric composite beams with different complex nonsmooth/discontinuous interfaces, we develop an R(x)-orthonormal theory, where R(x) is an integrable flexural rigidity function. The R(x)-orthonormal bases in the linear space of boundary functions are constructed, of which the second-order derivatives of the boundary functions are asked to be orthonormal with respect to the weight function R(x). When the vibration modes of the symmetric composite beam are expressed in terms of the R(x)-orthonormal bases we can derive an eigenvalue problem endowed with a special structure of the coefficient matrix A :=[aij ],aij= 0 if i + j is odd. Based on the special structure we can prove two new theorems, which indicate that the characteristic equation of A can be decomposed into the product of the characteristic equations of two sub-matrices with dimensions half lower. Hence, we can sequentially solve the natural frequencies in closed-form owing to the specialty of A. We use this powerful new theory to analyze the free vibration performance and the vibration modes of symmetric composite beams with three different interfaces. 展开更多
关键词 SYMMETRIC composite beams R(x)-orthogonality of second-order derivatives of boundary functions R(x)-orthonormal THEORY Non-smooth/discontinuous interface Sequentially closed-from natural frequencies
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Polarized proton beams from laser-induced plasmas
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作者 Anna Hützen Johannes Thomas +7 位作者 Jürgen Boker Ralf Engels Ralf Gebel Andreas Lehrach Alexander Pukhov T.Peter Rakitzis Dimitris Sofikitis Markus Büscher 《高功率激光科学与工程:英文版》 CAS CSCD 2019年第1期114-119,共6页
We report on the concept of an innovative source to produce polarized proton/deuteron beams of a kinetic energy up to several GeV from a laser-driven plasma accelerator. Spin effects have been implemented into the par... We report on the concept of an innovative source to produce polarized proton/deuteron beams of a kinetic energy up to several GeV from a laser-driven plasma accelerator. Spin effects have been implemented into the particle-in-cell(PIC) simulation code VLPL(Virtual Laser Plasma Lab) to make theoretical predictions about the behavior of proton spins in laser-induced plasmas. Simulations of spin-polarized targets show that the polarization is conserved during the acceleration process. For the experimental realization, a polarized HCl gas-jet target is under construction using the fundamental wavelength of a Nd:YAG laser system to align the HCl bonds and simultaneously circularly polarized light of the fifth harmonic to photo-dissociate, yielding nuclear polarized H atoms. Subsequently, their degree of polarization is measured with a Lamb-shift polarimeter. The final experiments, aiming at the first observation of a polarized particle beam from laser-generated plasmas, will be carried out at the 10 PW laser system SULF at SIOM, Shanghai. 展开更多
关键词 LASER-DRIVEN plasma ACCELERATOR PARTICLE-IN-CELL simulations POLARIZED gas-jet target POLARIZED PROTON BEAMS
Demonstration of high-dimensional free-space data coding/decoding through multi-ring optical vortices
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作者 付时尧 翟焱望 +3 位作者 周恒 张建强 殷慈 高春清 《中国光学快报:英文版》 SCIE EI CAS CSCD 2019年第8期16-20,共5页
Multi-ring optical vortices are a kind of structured beams that carry orbital angular momentum(OAM) and have concentrical doughnut intensity distributions. In this Letter, we present both theoretically and experimenta... Multi-ring optical vortices are a kind of structured beams that carry orbital angular momentum(OAM) and have concentrical doughnut intensity distributions. In this Letter, we present both theoretically and experimentally a scheme that employs the dimensions of both the OAM states and radial index of multi-ring optical vortices simultaneously to accomplish high-dimensional free-space data coding/decoding transmissions. Such a scheme can further improve the coding efficiency when limited OAM states are available. In the proof-ofconcept experiment, 64-ary coding/decoding employing 16 OAM states and four radial indices are present. Also,the coding/decoding performance when facing various atmosphere turbulences is evaluated. Furthermore, a 64 × 64 gray image(totally, 32,768 bits) is also transmitted through multi-ring optical vortices coding in free-space successfully, showing good transmission performance. 展开更多
关键词 optical BEAMS transmissions
40mPC简支T梁横隔板布置对结构受力影响分析 预览
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作者 刘雪君 刘泉 《价值工程》 2019年第28期216-218,共3页
桥梁横向连接刚度的大小直接影响结构的受力状态,本文以桥梁标准图跨径40m桥宽为12m的PC简支T梁为例,建立MidasFea有限元模型,并将横隔板的个数设置为3、5、7片,分析不同的横隔板布置方案对结构受力的影响。结果表明:横梁数目增加,结构... 桥梁横向连接刚度的大小直接影响结构的受力状态,本文以桥梁标准图跨径40m桥宽为12m的PC简支T梁为例,建立MidasFea有限元模型,并将横隔板的个数设置为3、5、7片,分析不同的横隔板布置方案对结构受力的影响。结果表明:横梁数目增加,结构的横向联系加强,使结构的内力在各主梁间分配较均匀,主梁的扭矩、扭转变形减小,避免了“单梁受力”的现象。 展开更多
关键词 T梁桥 MIDAS Fea模型 横隔板布置 受力分析
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Comparison of three kinds of polarized Bessel vortex beams propagating through uniaxial anisotropic media
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作者 刘佳伟 李海英 +3 位作者 丁炜 白璐 吴振森 李正军 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第9期237-248,共12页
A comparison of differently polarized Bessel vortex beams propagating through a uniaxial anisotropic slab is discussed in terms of the vector wave function expansions.The magnitude profiles of electric field component... A comparison of differently polarized Bessel vortex beams propagating through a uniaxial anisotropic slab is discussed in terms of the vector wave function expansions.The magnitude profiles of electric field components, the transformation of polarization modes, and the distributions of orbital angular momentum(OAM) states of the reflected and transmitted beams for different incident angles are numerically simulated.The results indicate that the magnitude profiles of electric field components for different polarization modes are distinct from each other and have a great dependence on the incident angle,thus the transformation of polarization modes which reflects the change of energy can be affected largely.As compared to the x and circular polarization incidences, the reflected and transmitted beams for the radial polarization incidence suffer the fewest transformation of polarization modes, showing a better energy invariance.The distributions of OAM states of the reflected and transmitted beams for different polarization modes are diverse as well, and the derived OAM states of the transmitted beam for radial polarization present a focusing effect, concentrating on the state between two predominant OAM states. 展开更多
关键词 ORBITAL ANGULAR MOMENTUM BESSEL vortex beams reflection and transmission polarization
基于连廊的隧道照明节能研究 预览
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作者 游峰 刘宜恩 刘易家 《重庆交通大学学报:自然科学版》 CAS CSCD 北大核心 2019年第6期37-41,共5页
通过建立自然光光照模型,得出自然光情况下光线的分布情况,在此基础上,将隧道入口段的加强照明换成连廊下的自然光照明,通过分析在连廊情况下的光照情况,建立连廊下隧道入口段的光照模型。以潮惠高速公路银山隧道段的设计模型为例,对入... 通过建立自然光光照模型,得出自然光情况下光线的分布情况,在此基础上,将隧道入口段的加强照明换成连廊下的自然光照明,通过分析在连廊情况下的光照情况,建立连廊下隧道入口段的光照模型。以潮惠高速公路银山隧道段的设计模型为例,对入口段采用连廊自然光照明的模型进行验证。研究表明:将隧道入口段的加强照明换成连廊下的自然光照明,可以很好的满足隧道入口前半段的照明需求。相比加强照明,大大降低了隧道入口处的照明耗电量,在同等条件下,入口段采用连廊自然光的照明方式较传统照明方式,降低隧道能耗比达16.69%。 展开更多
关键词 隧道工程 横梁 连廊 接近段亮度 入口段亮度 节能
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建筑基础中承受轴向压力的双参数弹性地基梁的稳态振动 预览
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作者 王亚升 郭红兵 王玉 《陕西交通职业技术学院学报》 2019年第3期5-10,共6页
弹性地基梁是土木工程结构中的基本构件,许多工程结构的计算都可以归结为弹性地基梁的计算。目前能够准确反应结构与地基相互作用的计算弹性地基模型较少,双参数弹性地基模型是其中之一。然而双参数地基模型的衰减参数γ难以准确选用,... 弹性地基梁是土木工程结构中的基本构件,许多工程结构的计算都可以归结为弹性地基梁的计算。目前能够准确反应结构与地基相互作用的计算弹性地基模型较少,双参数弹性地基模型是其中之一。然而双参数地基模型的衰减参数γ难以准确选用,一直制约着该计算模型在结构动力分析中的推广运用。以Hamilton原理为基础,从系统能量的计算出发,采用变分法推导出双参数地基上承受轴向力的梁的边界条件及控制微分方程。使用Matlab编写程序,采用迭代法计算得出承受轴向力的双参数弹性地基梁稳态振动时的内力幅值、变形幅值,并将计算结果与工程经验值进行比对。结果表明:该算法能够相对准确地求解结构稳态振动的问题,并准确得出衰减参数γ、剪切刚度与基床系数,为双参数弹性地基模型的推广应用扫除了障碍,具有广阔的应用前景。 展开更多
关键词 基础 双参数地基 最小势能原理 弯曲 稳态振动 固有频率
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Full vectorial feature of second-harmonic generation with full Poincaré beams
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作者 张莉 林飞 +1 位作者 邱晓东 陈理想 《中国光学快报:英文版》 SCIE EI CAS CSCD 2019年第9期78-82,共5页
We demonstrate the full vectorial feature of second-harmonic generation(SHG), i.e., from infrared full Poincaré beams to visible full Poincaré beams, based on two cascading type I phase-matching beta barium ... We demonstrate the full vectorial feature of second-harmonic generation(SHG), i.e., from infrared full Poincaré beams to visible full Poincaré beams, based on two cascading type I phase-matching beta barium borate crystals of orthogonal optical axes. We visualize the structured features of the vectorial SHG wave by using Stokes polarimetry and show the interesting doubling effect of the polarization topological index, i.e., a low-order full Poincaré beam is converted to a high-order one. However, the polarization singularities of both C points and L lines are found to keep invariant during the SHG process. Our scheme could offer a deeper understanding on the interaction of vectorial light fields with media and can be generalized to other nonlinear optical effects. 展开更多
关键词 Full vectorial FEATURE second-harmonic GENERATION full POINCARE BEAMS
Synthetic optical vortex beams from the analogous trajectory change of an artificial satellite
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作者 HAIPING WANG LIQIN TANG +5 位作者 JINA MA XIUYAN ZHENG DAOHONG SONG YI HU YIGANG LI ZHIGANG CHEN 《光子学研究:英文版》 CSCD 2019年第9期1101-1105,共5页
We propose a method to generate specially shaped high-order singular beams of pre-designed intensity distributions. Such a method does not a priori assume a phase formula, but rather relies on the 'cake-cutting an... We propose a method to generate specially shaped high-order singular beams of pre-designed intensity distributions. Such a method does not a priori assume a phase formula, but rather relies on the 'cake-cutting and assembly' approach to achieve the azimuthal phase gradient for beam shaping, inspired by the orbital motion trajectory change of an artificial satellite. Based on our method, several typical vortex beams with desired intensity patterns are experimentally generated. As an example, we realize optical trapping and transportation of microorganisms with a triangle-shaped vortex beam, demonstrating the applicability of such unconventional vortex beams in optical trapping and manipulation. 展开更多
关键词 SOV SLM SYNTHETIC optical vortex BEAMS from the analogous TRAJECTORY CHANGE of AN artificial satellite
Inverse Optimal Control of Evolution Systems and Its Application to Extensible and Shearable Slender Beams 预览
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作者 K.D.Do A.D.Lucey 《自动化学报:英文版》 CSCD 2019年第2期395-409,共15页
An optimal(practical) stabilization problem is formulated in an inverse approach and solved for nonlinear evolution systems in Hilbert spaces. The optimal control design ensures global well-posedness and global practi... An optimal(practical) stabilization problem is formulated in an inverse approach and solved for nonlinear evolution systems in Hilbert spaces. The optimal control design ensures global well-posedness and global practical K∞-exponential stability of the closed-loop system, minimizes a cost functional,which appropriately penalizes both state and control in the sense that it is positive definite(and radially unbounded) in the state and control, without having to solve a Hamilton-Jacobi-Belman equation(HJBE). The Lyapunov functional used in the control design explicitly solves a family of HJBEs. The results are applied to design inverse optimal boundary stabilization control laws for extensible and shearable slender beams governed by fully nonlinear partial differential equations. 展开更多
关键词 BOUNDARY CONTROL evolution system HILBERT space INVERSE optimal CONTROL slender BEAMS
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Comprehensive investigation on producing high-power orbital angular momentum beams by coherent combining technology
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作者 Dong Zhi Tianyue Hou +5 位作者 Pengfei Ma Yanxing Ma Pu Zhou Rumao Tao Xiaolin Wang Lei Si 《高功率激光科学与工程:英文版》 CAS CSCD 2019年第2期88-96,共9页
High-power orbital angular momentum(OAM)beams have distinct advantages in improving capacity and data receiving for free-space optical communication systems at long distances.Utilizing the coherent combination of a be... High-power orbital angular momentum(OAM)beams have distinct advantages in improving capacity and data receiving for free-space optical communication systems at long distances.Utilizing the coherent combination of a beam array technique and helical phase approximation by a piston phase array,we have proposed a generating system for a novel high-power beam carrying OAM,which could overcome the power limitations of a common vortex phase modulator and a single beam.The characteristics of this generating method and the orthogonality of the generated OAM beams with different eigenstates have been theoretically analyzed and verified.Also a high-power OAM beam produced by coherent beam combination(CBC)of a six-element hexagonal fiber amplifier array has been experimentally implemented.Results show that the CBC technique utilized to control the piston phase differences among the array beams has a high efficiency of 96.3%.On the premise of CBC,we have obtained novel vortex beams carrying OAM of±1 by applying an additional piston phase array modulation on the corresponding beam array.The experimental results agree approximately with the theoretical analysis.This work could be beneficial to areas that need high-power OAM beams,such as ultra-long distance free-space optical communications,biomedical treatments,and powerful trapping and manipulation under deep potential wells. 展开更多
关键词 ORBITAL ANGULAR MOMENTUM BEAMS COHERENT beam combination
Bending Solutions of FGM Reddy-Bickford Beams in Terms of Those of the Homogenous Euler-Bernoulli Beams
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作者 You-Ming Xia Shi-Rong Li Ze-Qing Wan 《固体力学学报:英文版》 SCIE EI CSCD 2019年第4期499-516,共18页
In this paper, correspondence relations between the solutions of the static bending of functionally graded material (FGM) Reddy-Bickford beams (RBBs) and those of the corresponding homogenous Euler-Bernoulli beams are... In this paper, correspondence relations between the solutions of the static bending of functionally graded material (FGM) Reddy-Bickford beams (RBBs) and those of the corresponding homogenous Euler-Bernoulli beams are presented. The effective material properties of the FGM beams are assumed to vary continuously in the thickness direction. Governing equations for the titled problem are formulated via the principle of virtual displacements based on the third-order shear deformation beam theory, in which the higher-order shear force and bending moment are included. General solutions of the displacements and the stress resultants of the FGM RBBs are derived analytically in terms of the deflection of the reference homogenous Euler- Bernoulli beam with the same geometry, loadings and end conditions, which realize a classical and homogenized expression of the bending response of the shear deformable non-homogeneous FGM beams. Particular solutions for the FGM RBBs under specified end constraints and load conditions are given to validate the theory and methodology. The key merit of this work is to be capable of obtaining the high-accuracy solutions of thick FGM beams in terms of the classical beam theory solutions without dealing with the solution of the complicated coupling differential equations with boundary conditions of the problem. 展开更多
关键词 Functionally graded material BEAMS Reddy-Bickford BEAM THEORY Euler- Bernoulli BEAM THEORY BENDING solution Shear deformation
Spectral measurement of coherence Stokes parameters of random broadband light beams
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作者 HENRI PARTANEN ARI T.FRIBERG +1 位作者 TERO SETALA JARI TURUNEN 《光子学研究:英文版》 CSCD 2019年第6期669-677,共9页
We introduce a spectrally resolved Young’s interferometer based on a digital micromirror device, a grating spectrometer, and a set of polarization-modulation elements to measure the spectral coherence(two-point) Stok... We introduce a spectrally resolved Young’s interferometer based on a digital micromirror device, a grating spectrometer, and a set of polarization-modulation elements to measure the spectral coherence(two-point) Stokes parameters of random light beams. An experimental demonstration is provided with a spatially partially coherent superluminescent diode amounting to a complex structure of spatio-spectral coherence induced by a quartzwedge depolarizer. We also show that the polarization and spatial coherence of light can vary with wavelength on a subnanometer scale. The technique is simple and robust and applies to light beams with any spectral bandwidth. 展开更多
关键词 SPECTRAL measurement light BEAMS
Terahertz wave generation from ring-Airy beam induced plasmas and remote detection by terahertz-radiation- enhanced-emission-of-fluorescence: a review
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作者 Kang LIU Pingjie HUANG Xi-Cheng ZHANG 《中国光电子学前沿:英文版》 EI CSCD 2019年第2期117-147,共31页
With the increasing demands for remote spectroscopy in many fields ranging from homeland security to environmental monitoring, terahertz (THz) spectroscopy has drawn a significant amount of attention because of its ca... With the increasing demands for remote spectroscopy in many fields ranging from homeland security to environmental monitoring, terahertz (THz) spectroscopy has drawn a significant amount of attention because of its capability to acquire chemical spectral signatures non-invasively. However, advanced THz remote sensing techniques are obstructed by quite a few factors, such as THz waves being strongly absorbed by water vapor in the ambient air, difficulty to generate intense broadband coherent THz source remotely, and hard to transmit THz waveform information remotely without losing the signal to noise ratio, etc. In this review, after introducing different THz air-photonics techniques to overcome the difficulties of THz remote sensing, we focus mainly on theoretical and experimental methods to improve THz generation and detection performance for the purpose of remote sensing through tailoring the generation and detection media, air-plasma. For the THz generation part, auto-focusing ring-Airy beam was introduced to enhance the THz wave generation yield from two-color laser induced air plasma. By artificially modulated exotic wave packets, it is exhibited that abruptly auto-focusing beam induced air-plasma can give an up to 5.3-time-enhanced THz wave pulse energy compared to normal Gaussian beam induced plasma under the same conditions. At the same time, a red shift on the THz emission spectrum is also observed. A simulation using an interference model to qualitatively describe these behaviors has be developed. For the THz detection part, the results of THz remote sensing at 30 m using THz-radiation-enhanced-emission- of-fluorescence (THz-REEF) technique are demonstrated, which greatly improved from the 10 m demonstration last reported. The THz-REEF technique in the counter-propagation geometry was explored, which is proved to be more practical for stand-off detections than co-propagation geometry. We found that in the counter- propagating geometry the maximum amplitude of the REEF signal is comparable to that in the 展开更多
关键词 ultrafast TERAHERTZ (THz) techniques THZ air- photonics ring-Airy beams THz-radiation-enhanced-emis- sion-of-fluorescence (THz-REEF) of air-plasma in co- propagation geometry THz-REEF of air-plasma in coun-ter-propagation geometry
Soliton guidance and nonlinear coupling for polarized vector spiraling elliptic Hermite–Gaussian beams in nonlocal nonlinear media
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作者 孙春志 梁果 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第7期252-258,共7页
We investigate the incoherent beams with two orthogonal polarizations in nonlocal nonlinear media, one of which is a fundamental Gaussian beam and the other is spiraling elliptic Hermite–Gaussian beam carrying the or... We investigate the incoherent beams with two orthogonal polarizations in nonlocal nonlinear media, one of which is a fundamental Gaussian beam and the other is spiraling elliptic Hermite–Gaussian beam carrying the orbital angular momentum(OAM).Using the variational approach, we obtain the critical power and the critical OAM required for the vector spiraling elliptic Hermite–Gaussian solitons.In the strong nonlocality region, two components of the vector beam contribute to the nonlinear refractive index in a linear manner by the sum of their respective power.The nonlinear refractive index exhibits a circularly symmetrical profile in despite of the elliptic shapes for spiraling Hermite–Gaussian beams.We find that in the strong nonlocality region, the critical power and the rotational velocity are the same regardless of the relative ratio of the constituent powers.The nonlinear refractive index loses its circular symmetry in weak nonlocality region, and the nonlinear coupling effect is observed.Due to the radiation of the OAM, the damping of the rotation is predicted, and can be suppressed by decreasing the proportion of the spiraling elliptic component of the vector beam. 展开更多
关键词 VECTOR SOLITONS Hermite–Gaussian beams orbital angular momentum VARIATIONAL approach
Stresses of orthotropic laminated beams subjected to high temperature and mechanical load 预览
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作者 Zhong Zhang Ding Zhou +1 位作者 Xiuli Xu Xuehong Li 《力学快报:英文版》 CAS CSCD 2019年第5期279-284,I0003共7页
Thermo-elastic analysis of simply-supported orthotropic laminated beams subjected to high temperature and mechanical load is presented on the basis of the exact two-dimensional thermoelasticity theory.The beam is comp... Thermo-elastic analysis of simply-supported orthotropic laminated beams subjected to high temperature and mechanical load is presented on the basis of the exact two-dimensional thermoelasticity theory.The beam is composed of several orthotropic layers,each with temperaturedependent material properties.The governing equation for each layer is analytically solved using the state space method.The displacement and stress solutions of the beam are obtained using the transfer-matrix method.A numerical example is included to study the effects of temperature on the mechanical responses of a sandwich beam.The results reveal two main effects of temperature:(i)inducing deformations and stresses by itself;(ii)affecting the deformations and stresses induced by the mechanical load. 展开更多
关键词 ORTHOTROPIC laminated BEAMS TEMPERATURE-DEPENDENT material properties THERMO-ELASTICITY theory State space METHOD TRANSFER-MATRIX METHOD
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成都京东方洁净厂房大跨度屋面钢结构施工技术 预览
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作者 张笑冬 丛辉 +2 位作者 邓文瑶 张鑫 龚小英 《施工技术》 CAS 2019年第10期25-29,81共6页
针对成都京东方洁净厂房屋面超大超长,屋面钢梁大跨度、超重大截面导致施工难度极大的特点,对超重大截面屋面钢梁吊装关键施工技术:双机抬吊,滑移、分段安装,履带式起重机上楼、筏板预留通道;大跨度屋面桁架钢结构关键施工技术:液压整... 针对成都京东方洁净厂房屋面超大超长,屋面钢梁大跨度、超重大截面导致施工难度极大的特点,对超重大截面屋面钢梁吊装关键施工技术:双机抬吊,滑移、分段安装,履带式起重机上楼、筏板预留通道;大跨度屋面桁架钢结构关键施工技术:液压整体提升,滑移,分段拼装、整榀吊装等进行了介绍。工程实践表明,针对不同施工部位及施工环境采用合理的施工方式,取得了良好的经济效益和社会效益。 展开更多
关键词 钢结构 工业厂房 屋面 大跨度 桁架 施工技术
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