激光反射镜与诱导透射滤光片工艺分析

随着光通信和光信息技术的迅速发展,介质高反射镜和窄带滤光片倍受人们关注,有机光学薄膜滤波器材料及器件将日益受到重视.采用一个低通滤波器和高通滤波器在其通带叠合处便可产生一个优良的窄带滤波器.详细介绍了几种光学薄膜器件激光反射镜、诱导透射滤光片(ITF)和微片式激光器的混合材料及制备工艺,并给出其设计方法,对批量生产将有极大的促进作用.     

加速器噪声对远红外FEL振荡器影响的模拟研究

采用FEL一维脉冲模型，针对中国原子能研究院的远红外FEL振荡器，模拟研究了加速器噪声对FEL的影响。对电子束微脉冲的时间晃动和能量波动所引起的光功率波动及光谱中心晃动进行了模拟计算，在计算中还分别考虑了噪声频率、振幅的大小产生的直接影响以及腔失谐的间接影响。     

Stability regime study of a nonlinear mirror mode-locked laser

A diode array pumped nonlinear mirror mode-locked (ML) laser is developed and the regime of the stable operation for such a system is found to occur for a little detuning of intra-cavity second harmonic phase-matching. The existing theory of mode-locking using a fast saturable absorber (FSA) is used to derive corresponding equivalent parameters for a fast nonlinear mirror saturable absorber. The condition for stable single pulse ML operation is evaluated in terms of small signal gain of the laser medium and small signal nonlinear loss. The analysis explains the experimental observations and differentiates the regime of operation in ML, Q-switching and cw mode-locking.     

Conditions for balancing a rotating body in an isolated system with automatic balancers

Conditions are established for automatic balancers with rigid bodies to balance a rotating body that undergoes spatial motion and is a component of an isolated system. It is discovered that a rotating oblate body can be statically balanced when the balance plane is rather close to the center of mass of the system. It is also established that if the rotating body is prolate, the nutation angle can be initially decreased by balancing the body; however, it will then increase because of the dissipation of energy in the system __________ Translated from Prikladnaya Mekhanika, Vol. 43, No. 11, pp. 113–120, November 2007.     

Bound Motion of Bodies and Paticles in the Rotating Systems

The Lagrange theory of particle motion in the noninertial systems is applied to the Foucault pendulum, isosceles triangle pendulum and the general triangle pendulum swinging on the rotating Earth. As an analogue, planet orbiting in the rotating galaxy is considered as the giant galactic gyroscope. The Lorentz equation and the Bargmann-Michel-Telegdi equations are generalized for the rotation system. The knowledge of these equations is inevitable for the construction of LHC where each orbital proton “feels” the Coriolis force caused by the rotation of the Earth.     

Solution to causality paradox upon total reflection

A dispute about the existence of an additional time (named as the Goos-H?nchen time) associated with the Goos-H?nchen shift in total reflection has recently arisen. At the same time, an inconsistency between the optical ray model and the electromagnetic theory also appears in the optical planar waveguide. By analyzing light propagation in an optical planar waveguide with both the zigzag-ray model and the electromagnetic theory, this paper shows that the Goos-H?nchen time really exists, and the total time delay upon total reflection upon an ideal nonabsorbing plasma mirror is the sum of the group-delay time and the Goos-H?nchen time. The causality paradox of total reflection of a TM wave upon an ideal nonabsorbing plasma mirror is also solved taking into consideration the negative Goos-H?nchen shift. Finally, the expression of the group velocity of the guided mode in optical planar waveguide was obtained, which clearly shows that the time delay upon total reflection is the sum of the group-delay time and the Goos-H?nchen time at given any time.     

Exposure of First Mirror and Protection Simulation in HL-2A Tokamak

First mirrors are the facing components of plasma optical diagnostics system for superconductivity and other fusion devices. Due to high level of neutron and gamma radiation, the lifetime and optical state of first mirror will face an enormous challenge. The degradation of the optical character on the mirror surface mainly comes from the two opposite processes, one is erosion, the other is re-deposition. Which proces plays more important role need testing in present machines. Before 2001 the experimental studies mainly put on material character simulation in a laboratory. Recently, the sample of the first mirror has been investigated in actual fusion device and modification of mirror optical properties was made. But how to protect mirror and make the lifetime longer will be an issue need solving urgently.     

On the Chiral Ring of Calabi–Yau Hypersurfaces in Toric Varieties

This paper is devoted to the calculation of the B-model chiral ring, used in physics, for semiample Calabi–Yau hypersurfaces. We also study the cohomology of semiample hypersurfaces.     

环形腔处理机匣对低速风扇性能和失速裕度的影响

本文从实验角度探讨一种新型带有环形腔的槽式处理机匣对风扇性能和失速裕度的影响。结果表明:处理机匣的槽向和槽与转子轴向重合度是影响风扇性能的两个主要参数,应用于本实验的低速风扇中,圆弧槽槽向与转子叶型方向相错,槽与转子轴向重合度为1/3的环形腔处理机匣对风扇失速裕度有明显提高,但效率略有下降。同时随环形腔腔体体积增大风扇裕度有明显振荡变化,进一步的规律值得深入探讨。     

Viscous Interaction Between a Vortex Tube and a Rotating Spherical Particle

The transient advection of a cylindrical vortex tube in a viscous incompressible flow field and its interaction with a rotating/spinning spherical particle has been investigated numerically at Reynolds numbers in the range of 20≤ Re≤200 for angular velocities of 0≤Ω≤0.5. The effects of vortex parameters such as size, circulation strength and initial position relative to the particle, on the temporal behavior of the lift and drag forces are studied. Vortex‐sphere interactions bring about major changes in the flow field particularly when coupled with particle rotation. It is observed that the forces acting on the particle are significantly influenced during the time that the vortex core is in the vicinity of the particle. The extent of these local changes are about ±30% in the drag coefficient and about ±200% in the lift coefficient as compared to flow over a rotating solid sphere with no vortex interaction. It is also found that a vortex with core radius between one and two particle diameters creates the strongest temporal variations in the lift and drag coefficients. Furthermore, maximum lift variations occur for the vortex‐particle head on collision, while a vortex with an offset distance of about one diameter from the principal flow axis generates the maximum drag variations.