查询词典 beams

Concretely, firstly with Timoshenko beams, the fundamental formulae of solutions of dynamical equations, boundary conditions and initial conditions have been transformed by Laplace transformation. Secondly, in the Laplace regions , we gain the analytical solutions of impact forces at the impact contact points, shear and maximum inverse stress of beams. Then, by using Durbin numerical inverse method, we gain the numerical solutions of Timoshenko beams under various restriction conditions. Moreover, the graphs about impact forces at the impact contact points, shear and maximum inverse stress of beams can be obtained too.

把Timoshenko梁力学模型动力学方程的基本解形式、边界条件以及初始条件进行Laplace变换，在Laplace区域得到了冲击接触处的冲击力、整个梁的最大弯曲应力和剪力的解析解，然后利用Durbin数值反演的方法得到了各种约束条件下的Timoshenko梁模型时间-空间的数值解，得到了冲击接触处的冲击力、梁各处的最大弯曲应力和剪力的曲线图。

By using Zernike polynomials to describe the wavefront distortion of beams, the propagation properties of the flattened Gaussian beams, super Gaussian beams, Gaussian beams and plane waves passing through an aberrated lens or an aberrated annular lens are studied based on the generalized Huygens-Fresnel diffraction integral.

以广义惠更斯—菲涅尔衍射理论为基础，采用Zernike多项式描述像差光束畸变波前相位，研究了平顶高斯光束、超高斯光束、高斯光束以及平面波通过像差透镜和环状像差透镜的传输。

Secondly, three kinds of mathematics model of optical vortex beams were introduced here. Then the propagation dynamics of optical vortex beams through the non-axis symmetry system is studied, this chapter includes the introduction of the symmetry vortex beam and the non- symmetry vortex beam, the deduction of the Collins diffract integral formula for the non-axis symmetry system, and the transformation of the vortex beam passing through the non-axis symmetry system has been described by using the numerical simulation. Then the general calculation for the orbit momentum of vortex beams, the matrix form for the orbit momentum of vortex beams, and the photon method to describe the orbit momentum of vortex beams are also introduced here. Finally, the interference about optical vortex beams was studied.

本文对涡旋光束进行了较为全面的介绍和研究，主要内容包括：（1）光学涡旋光束的基本理论，主要是介绍了单个光学涡旋光束在柱坐标中的一些表征，涡旋光束的奇异相位和光学涡旋的相位结构；（2）光学涡旋光束的三种数学模型；（3）光学涡旋光束在非轴对称光学系统中的传播动力学，其中介绍了对称涡旋光束与非对称涡旋光束，推导了非轴对称光学系统的 Collins 衍射积分公式，并利用计算机模拟图描述了对称涡旋光束经过非轴对称光学系统后涡旋形态的改变；（4）涡旋光束轨道角动量的一般计算，涡旋光束轨道角动量的矩阵形式，光子法描述涡旋的轨道角动量；（5）涡旋光束的干涉。

Combining with the National Natural Science Foundation ofChina(No.50478032), following researches were done in this thesis: 1 The variation regularity of the ultimate anti-bending capacity of therectangular-sectioned beam with different corrosion has been obtained through thequalitative analysis of 48 beams (32 corroded beams and 12 comparing beams) withaccelerated corrosion; 2 The conclusion has been obtained that the strain of corroded steel bar andconcrete no longer fit in with the assumption of plane section through the analysis ofthe strain data, the strain relation of steel bar and concrete in the mid-span section ofvariously corroded beams at ultimate has been obtained. Through the building of newgeometric relation, the expression of the height of compressive area in the corrodedbeam with rectangular section has been deduced, and the formula with corrosion rateas the main variable for the anti-bending capacity of the corroded concrete beam hasbeen suggested and verified by experiment.; 3 The influence of steel bar corrosion and the concrete regression to the flexureductility coefficient of the corroded structure component has been analyzed. Based onthe relation of steel bar and concrete at yield and ultimate, the expression for theflexure at yield and ultimate of corroded reinforced concrete beam, and the model forthe calculation of the flexure ductility has been built.

本文结合国家自然科学基金项目(50478032)"既有钢筋混凝土桥梁时变可靠度研究"，主要进行了以下研究工作： 1通过对48根快速锈蚀钢筋混凝土矩形截面梁(32根锈蚀梁和12根对比试验梁)数据的定性分析，得到了不同锈蚀率下，锈蚀钢筋混凝土矩形截面梁极限抗弯承载力的变化规律； 2通过对应变数据的分析，论证了锈蚀构件钢筋和混凝土的应变不再符合平截面假定的结论，并通过回归分析得出了不同锈蚀率的螺纹钢筋梁和光圆钢筋梁在极限弯矩作用下，跨中截面处钢筋应变和钢筋处混凝土应变的关系，通过构造新的几何关系，得出了锈蚀钢筋混凝土矩形截面梁计算受压区高度的表达式，既而得出了以锈蚀率为主要变量的锈蚀钢筋混凝土矩形截面梁的正截面抗弯计算建议公式，并通过试验数据加以验证； 3分析了钢筋锈蚀和混凝土劣化对锈蚀构件曲率延性系数的影响，结合钢筋屈服和极限弯矩两种状态下钢筋和混凝土的应变关系，分别得到了锈蚀钢筋混凝土矩形截面梁屈服曲率和极限曲率的计算表达式；既而推导出曲率延性系数的计算模型。

We take sech form ansatz and solve the CNLS equations through variational approach. We obtain the analytical expression of nonlinear coupling term, which is in the lagrangian of CNLS. We apply a potential well model to analyze the interaction properties of self-trapping beams in detail, the results show that the interaction do not change the profile of the beams, two beams keep oscillating around their collective center periodically. The amplitude and period of this oscillation are both determined by initial separation of two beams.

我们采用Sech函数为试探函数，用变分法求解CNLS方程，（1）给出了CNLS方程所对应的拉格朗日中的非线性耦合项的解析表达，（2）利用势阱模型详细分析两自陷光束之间相互作用的特性，结果表明，相互作用没有改变孤子的形态，它们分别在与传播方向垂直的方向上绕它们的公共中心做往复振动，振动幅度及周期都取决于两光束的初始分隔。

Holographic lithography method is one of them, which means that fabrication of 1D, 2D and 3D periodical microstructures by interference of two beams, three or four noncoplanar beams, multiple mutually coherent laser beams are made to intersect and interfere, producing period patterns of light and dark areas repeated on a scale proportional to the wavelength of the beams used.

全息光子晶体的实验制备及缺陷引入在光子晶体的实验制备中我们主要研究两个方面，一是激光全息干涉法一步成型制备大规模无缺陷的光子晶体，二是用单光子和双光子聚合相结合的办法，在光子晶体中引入缺陷。

Seventeen simply supported beams with the dimensions of 150 × 250 × 2600mm include nine secondary-load reinforced concrete beams reinforced by CFRP, six RC beams strengthened with CFRP directly and two unstrengthened control beams were experimentally investigated.

本次试验共设计了17根截面尺寸为150mm×250mm，梁长为2600mm的试验梁，其中9根为碳纤维布加固的具有不同初始荷载的钢筋混凝土梁，6根为碳纤维布直接加固的钢筋混凝土梁，2根为对比钢筋混凝土梁。

The result indicates that three groups of concrete beams strengthened by anchor-bolted steel plate can be loaded as far as they were destroyed; compared with unstrengthened beams ,these beams strengthened by steel plate using adhesive or anchor all can achieve a seventy percent higher loading capacity and thirty percent higher stiffness. On the condition that with the same steel plate ,concrete beams strengthened by bolting steel plate can work as good as those beams strengthened by using adhesive.

试验结果表明：三种锚固布置方式加固梁都能保证钢板与混凝土联合工作直至梁破坏；与未加固梁比较，锚固钢板加固梁和外粘钢板加固梁一样，都能有效提高梁的承载力和刚度，其中承载力提高幅度约为70%；刚度提高约为30%，这说明在钢板量相同的情况下，锚固钢板加固梁能够达到与粘结加固基本相同的加固效果。

The elastic supporting forces are regarded as loads and act reversely on longitudinal beams, then the forces acting on longitudinal beams are calculated. Through structure selection, the large rectangular aqueduct bridge with high side beams should be adopted firstly. Because the side beams may reduce the middle beam loads, the span of aqueduct bridge can be increased.

通过结构形式的比较，指出具有大边梁的多纵梁矩形渡槽其侧墙兼做纵梁用，充分利用侧墙刚度大的特点，使横向挡水和纵向承重结合在一起，可以有效地减小水荷载对中纵梁的作用，从而增加渡槽的跨越能力，在大型渡槽的设计中应优先采用。

Carved beams and painted ridgepoles have a history of over 2000 years.

雕梁画栋(carved beams and painted ridgepoles)有着2000多年的历史。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。