LETTER: Gauge Choice and Geodetic Deflection in Conformal Gravity

Conformal gravity has been proposed as an alternative theory of gravity which can account for flat galactic rotation curves without recourse to copious quantities of dark matter. However it was shown that for the usual choice of the metric, the result is catastrophic for null or highly relativistic geodesics, the effect is exactly the opposite yielding an effective repulsion and less deflection in this case. It is the point of this paper, that any result for massive geodesics depends on the choice of conformal gauge, in contradistinction to the case of null geodesics. We show how it is possible to choose the gauge so that the theory is attractive for all geodesics.     

Self-Bending of a Laser Beam in Photorefractive Crystals with Variable Nonlinearity Coefficient

The self-bending of a laser beam in photorefractive crystal is considered in the case in which the coefficient of photorefractive diffusion nonlinearity changes along deflection path. The bent trajectory is calculated analytically and the obtained result is compared with those reported before.     

激光抽运极化原子束磁偏转铀浓缩方案

将激光抽运选择性极化原子束磁偏转方案用于铀同位素浓缩,考察了铀原子基态各子能级的磁偏转特性,提出了选择性光轴运极化的实验方案,讨论了可能得到的浓缩结果。     

Reply to the comments of M.E. Golmakani and J. Rezatalab,Comment on “Nonlocal third-order shear deformation plate theory with application to bending and vibration of plates” (by R. Aghababaei and J.N. Reddy,Journal of Sound and Vibration 326 (2009) 277–289), Journal of Sound Vibration, 333 (2014) 3831–3835

Golmakani and Rezatalab [1] suggested in their paper that the deflection of a simply supported nonlocal elastic plate under uniform load is not affected by the small length scale terms. They based their proof on the use of Navier?s method using a sinusoidal-based deflection solution. This insensitivity of the deflection solution of a simply supported nonlocal elastic plate with respect to the small length terms of Eringen?s model is not correct, as already detailed in the literature (for example, see [2] for beam problems). In fact, the deflection of the nonlocal plate (in the Eringen sense) is larger than the one of the local case, as shown in many papers available in the literature. We prove in this reply to the authors that the Navier?s method has to be correctly applied for highlighting the specific sensitivity phenomenon of the deflection solution, as compared to exact analytical solution.     

关于利用激光光束偏转法测量热扩散率的研究

本文介绍了激光光束偏转法测量材料热扩散率的原理,从理论上分析了光的粒子性和光的衍射限制了该方法对热扩散率的测量精度,指出了提高测量精度的关键在于提高信号对光束偏转的灵敏度为此给出了一种带有Ronchi光栅的迈克耳孙干涉仪的探测装置,从而使灵敏度提高了约5.3倍.     

Deflection Angle and R-Charged Black Holes

In this paper we consider R-charged black holes with three electrical charges and study deflection angle. We confirmed result of previous study that the black hole charges increased the deflection angle.     

静态球对称引力场中光线偏折的几何算法

光线的引力偏折和光在介质中的折射有统一的地方,本文采用几何光学的方法讨论星光掠过太阳时的偏折角度,所得结果和经典文献一致.     

Photothermal deflection microscopy for imaging sub-micronic defects in optical materials

Photothermal deflection is widely used to study defects in optical coatings and role of these defects in laser damage. Because defects responsible for laser damage are assumed to be nanometer-sized and lowly absorbing, both high spatial resolution and high sensitivity are required to detect them. In this work we theoretically and experimentally explore the capability of collinear photothermal deflection to give micronic resolution by reduction of the pump beam diameter. Thanks to a model describing temperature distribution and photothermal deflection, we have studied the effects of pump beam focusing on photothermal deflection. Then, we have developed a high resolution, high sensitivity microscope based on the photothermal deflection of a transmitted probe beam. The setup is characterized and the theoretical predictions are checked. We present a test of lateral spatial resolution obtained on specially prepared absorbing resolution targets and show that a lateral spatial resolution of 1 μm is reached on non-isolated defects. In case of single defects, we expect that 10 nm sized defects could be detected.     

关于声光效应光束偏转角的实验研究

对声光效应中光束偏转角进行了一系列实验研究.基于传统声光效应的基本原理,建立了光束偏转角理论模型并进行了相关计算.在此基础上进行声光效应的布拉格衍射实验.大量实验结果显示,所测量到的光束偏转角和理论值存在一定的差距.     

匹配高斯光束在耗散晶体中的孤波演化及偏转特性

研究了匹配的高斯光束在加外电场的耗散型光伏光折变晶体中的动态演化及其偏转特性.结果表明，对于给定的耗散系统，若该系统能支持某一特定的耗散全息屏蔽光伏明孤子，也可能找到与之相匹配的高斯光束，则该匹配的高斯光束能在此给定的耗散系统中演化成稳定的屏蔽光伏空间孤子.同时，考察了扩散效应对此匹配的高斯光束的影响，结果显示，扩散效应将造成此匹配的高斯光束孤波在演化过程中产生偏转现象，而且其偏转过程与之相对应的明孤子的偏转过程具有极其类似的特征.通过比较研究匹配的高斯光束与耗散全息屏蔽光伏明孤子的偏转特征曲线，我们发现，对于匹配的高斯光束，其空间偏转的数值计算结果与明孤子偏转的解析计算结果非常接近.总之，在耗散系统中，匹配的高斯孤波的动态演化特性(包括偏转过程)与耗散全息屏蔽光伏明孤波的演化特性是相符合的.因此，人们往往可直接用匹配的基模高斯光束代替耗散全息屏蔽光伏明孤波，为理论分析和实验研究提供了便利.     

Critical parameters of nuclear magnon Bose–Einstein condensation in systems with dynamic frequency shift

The critical conditions for the Bose–Einstein condensation of quasi equilibrium nuclear magnons in the easy-plane antiferromagnets CsMnF₃ and MnCO₃ are theoretically derived. Both systems possess the dynamic frequency shift, the dependence of the precession frequency on the magnetization deflection angle and one is able to observe the magnetic resonance signals in very non-equilibrium conditions when the frequency of pumping is higher than precession frequency. The frequency difference in this case can be compensated by increasing the deflection angle.     

Deconvolution of loss features from electron spectra

The problem of deconvoluting loss features from energy spectra of electrons emitted from solids is investigated. A new formula is found for the case of an exponentially decreasing intensity from the solid surface of electron emitters. This as well as a formula for the case of a homogeneous distribution of electron emitters is studied in detail. Central in the formulas is the cross section for inelastic scattering. Under the assumption that angular deflection of electrons can be ignored the formulas are exact, i.e. the effect of all multiple scattering events is included. Through numerical calculations on Al spectra the effect of deconvolution is tested, and it is demonstrated that a small deviation from the exact procedure can result in spurious structure in the deconvoluted spectrum.     

细电子束像差与畸变参量非劣解中的最优解

以电子束偏转磁场的像差和畸变为目标,对参量进行非劣解中找出贴近理想的最优解。以SDS-3电子束曝光机的磁复合偏转系统为基础,分析了像差与电子束主轨迹的关系。并给出了磁聚焦和静电的偏转场相复合情况下竖轴的3级几何像差系数和1级色差系数公式。应用中表明,复合系统结构简单紧凑,像差小而可以不用动态校正。     

Deflection tomographic reconstruction of a complex flow field from incomplete projection data

Tomographic techniques are used for the investigation of complex flow fields by means of deflectometric methods. In this experiment, a modified algebraic reconstruction technique (ART) was applied to moiré deflection tomography. The algorithm was derived from the basic deflection formula and the deflection angles were used directly in iteration, which is completely different from the conventional ARTs with integral calculation that are commonly used in deflection tomography. A smoothing scheme was employed to improve the reconstruction under ill-posed conditions. The reconstruction technique was tested using simulated data for incompleteness conditions similar to those found in the experimental data. The complex density field with an opaque object in a supersonic wind tunnel was reconstructed from limited view angle projections, and the experimental reconstruction was then compared with the result obtained from the computational fluid dynamic analysis. The following paper details the experiment and discusses some measurement errors that occurred in the process.     

The method of virtual quanta as a probe of the equivalence principle

We consider bremsstrahlung encounters between a test body of massm, chargee, and a large fixed massM with chargeQ. We use the method of virtual quanta, and calculate the total electromagnetic and gravitational energy radiated in such encounters. We consider both the case in which the deflection is principally electromagnetic in nature, and the case in which the deflection is principally gravitational. The results are interpreted by considering the predictions of the equivalence principle, for the behavior of the test particle,and for the behavior of the virtual quanta. As expected from the equivalence principle, the total radiation produced is larger for electromagnetic deflection than for a gravitational deflection through the same angle.Dedicated to the memory of Alfred Schild, born7 September 1921; died 24 May 1977. A good man, a great scholar, the best of friends.Research supported in part by NSF grant no. PHV76-07919 and by NATO Research grant no. 1002.     

A new rectangular beam theory

A new theory for beams of rectangular cross-section which includes warping of the cross-sections is presented in the present work. By satisfying the shear-free conditions on the lateral surfaces of the beam a pair of coupled equations of motion are obtained such that no arbitrary shear coefficient is required. It is shown that the uncoupled equation for the transverse displacement is the same as the corresponding equation in Timoshenko beam theory provided that for the Timoshenko equation the shear coefficient is taken to be $\text{5}\text{6}$; this value lies within the range of values, 0·822–0·870, appearing in the literature for the beam of rectangular cross-section. Results for two typical static examples are given for both the new theory and Timoshenko beam theory. These results are compared with the solutions of the comparable problems in the linear theory of elasticity. For the end loaded cantilever beam the new theory predicts the same result for the neutral surface deflection as does the linear theory of elasticity while Timoshenko beam theory underestimates the shear correction term by 20%. For the uniformly loaded and simply supported case both beam theories provide the same overestimate of the central deflection when compared with the theory of elasticity solution.     

电子束曝光机偏转系统及可动物镜分析

电子束大扫描场偏转系统设计中 ,像差的确定是一个必须解决的实际问题。以SDS 3电子束曝光机的磁复合偏转系统为基础 ,以双通道扫描原理进行扫描 ,分析了像差与电子束主轨迹的关系。给出了可动物镜的条件 ,并利用这一条件分析电子束最佳轨迹的结构和方法。并使用计算机辅助设计研究电子束曝光机聚焦偏转系统的结构。由该电子束曝光机试验结果表明 ,复合系统结构简单紧凑 ,像差小而可以不用动态校正。采用矢量描写电子轨迹 ,以积分式表示像差。以 0 .0 0 5rad半张角 ,5× 10 -5的高压纹波 ,5 0mm的像距 ,10mm× 10mm扫描场的边脚处 ,使动态校正前的总像差为 0 .0 3μm。     

Zum Kontrast an Versetzungen im Röntgenbild

The causes of contrast at dislocations on X-ray topographs taken with different techniques are discussed. It is shown that a variety of mechanisms may be important for the image formation and the type of contrast observed. Particular attention is paid to the role which the deflection of wavefield rays in the long reaching strainfield of a dislocation may play in the formation of the dislocation image. For the case of dislocations imaged by the double crystal method paths of wavefield rays have been calculated numerically. Since in this case Braggcase wavefields are involved, the general theory of wavefield propagation in a weakly deformed lattice²⁴ had to be used. The results confirm the assumption that deflection of wavefield rays can contribute considerably to dislocation images obtained in X-ray topography.     

Numerical Simulation and Analysis on Deflection of Silicon Mirrors Irradiated by High Power Laser

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Spherically Symmetric Wormhole Gravitational Lens Deflection Angle Signifying Braneworld Cosmology

Previously, the gravitational lens of a wormhole was introduced by various researchers. Their treatment was focused basically on the lens signature that describes wormhole geometrical character such as the differences from a black hole or between any various types of wormhole models. The braneworld scenario provides the idea of spacetime with underlying extra-dimensions. The inclusion of extra-dimensional terms in the lens object spacetime line element will result in some variation in the expression for its gravitational lens deflection angle.Thus in this paper we investigate such variation by deriving this deflection angle expression. As such, this paper not only shows the existence of such variation but also suggests the potential utilization of gravitational lensing to prove the existence of extra dimensions by studying the deflection angle characteristic in accordance with the spacetime expansion rate of the universe.