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171.
172.
Makoto Kasu Rangaiya Rao Susumu Noda Akio Sasaki 《Journal of Electronic Materials》1991,20(9):691-693
Properties of theDX centers in Al0.5Ga0.5As bulk alloy (b-AL), (AlAs)2 (GaSa)2 ordered superlattice (o-SL) and (AlAs)
m
(GaAs)
n
disordered superlattice (d-SL) (m = 1, 2, 3,n = 1, 2, 3) with the same macroscopic composition were measured and compared. By deconvolution of deep level transient spectroscopy
(DLTS) spectrum due to theDX center, we have found a decrease in the number of separate peaks in DLTS spectrum in an intentionally atomic ordered arrangement.
Visiting Scholar of the Japan Society for the Promotion of Science. On leave from Department of Electrical Engineering, San
Jose State University, San Jose, California 95192-0084, USA. 相似文献
173.
174.
175.
精确定位物方焦面位置的简便方法 总被引:2,自引:0,他引:2
提出一种利用细激光束和全息光栅精确定位光学系统物方焦平面位置的方法,可用于光学傅里叶交换、光学信息处理系统的调整。其优点是所用光学元件少,操作简便。 相似文献
176.
为了精确计算束流在离子光学系统中的传输,用Visual FORTRAN 6.5语言编写了一个计算程序,长约13000行. 此程序可以计算由三圆筒单透镜、三膜片单透镜、双元筒透镜、均匀场静电加速管、磁四极透镜、六极磁铁、静电四极透镜、偏转磁铁、螺线管透镜、ExB~正交电磁场分析器、静电偏转器、漂浮管、QWR(Quarter Wave Resonators)和SLR(Split Loop Resonators)射频加速元件等元件任意组成的离子光学系统. 粒子轨迹的计算可精确到三级近似. 粒子的分布类型也可以有多种选择. 程序具有最优化计算功能,即可以自动调整元件的参数,以实现所需要的光学条件. 各元件之后的横向和纵向相图以及系统的束流包络线以图形方式显示在屏幕上. 相似文献
177.
直线加速器驻波腔中的瞬态束流负载效应 总被引:1,自引:0,他引:1
在高能加速器中, 随着单个束团和束团串中电荷量的提高, 当粒子束穿过加速腔的时候, 感应出的瞬态束流负载电压也越来越高. 但是, 在通常分析束流负载的时候, 往往对稳态束流负载研究的比较多, 而对瞬态束流负载的研究要相对少一些. 本文首先对束流负载的瞬态特性和束团穿过加速腔时高频源所看到谐振腔谐振频率的变化方式进行了分析, 然后又对两种情况下谐振腔的最优失谐条件进行了讨论, 并给出了相应的解析公式. 在第1种情况下, 当粒子束穿过加速腔的时候, 谐振腔的自然谐振频率能够及时地得到调节, 从而使高频源的电流与谐振腔的腔压同相, 以提高高频源的效率; 在第2种情况下, 当粒子束穿过加速腔的时候, 谐振腔的自然谐振频率保持不变, 不能被调节. 最后, 还对BEPCⅡ现有预注入器的预聚束腔、BEPCⅡ未来预注入器的两个次谐波聚束腔中的瞬态束流负载效应进行了分析. 相似文献
178.
After the laser was invented in 1960, a phase conjugation mirror has been respected to be the most fantastic one for the laser
resonator composition because it can compensate any distortions of the laser beams occurred by the many inhomogenuities of
the laser media and optical components. Among the many phase conjugation configurations, the stimulated Brillouin scattering
phase conjugation mirror is the most simple one and many researchers have tried to utilize it to develop high power/energy
laser systems. For realizing a high energy/power laser system the thermal problem is the most difficult to solve, and some
researchers suggested a beam combination technique to reduce the thermal load of the big laser media to many small sized ones.
To accomplish the beam combination using stimulated Brillouin scattering phase conjugation mirrors (SBS-PCMs), it is necessary
to lock/control the phases of the SBS-PCMs. And some researchers have developed several ways for it, but they can lock the
phases of a limited number of beams overlapped at the foci less than 5, or lock the phases by back-seeding technique but it
loses the phase conjugation characteristics. For realization of the laser fusion driver, it is necessary to combine more than
10 or 100 beams. And the authors have developed recently a new phase controlling/locking technique which is isolated and independent
totally from other beams and it can be applied to an unlimited number of beams in principle. 相似文献
179.
The mechanism of the slowly opened Q-switch operation was investigated thoroughly. Maximum energy extraction from the resonator
could be optimized, and the smallest output beam divergence could be achieved. In this article, we present a detailed analysis
that has numerically verified the mode-selection mechanism in the slowly opened Q-switch operation, and the degree of the
smaller output laser beam divergence that has been achieved. The mechanism of the slowly opened Q-switch operation is the
inherent advantage of the passive saturable absorber in this operation. We can use the maximum energy extraction and the smallest
output beam divergence results of the slowly opened Q-switch operation to design and optimize various passive saturable absorbers:
plastic dye sheets, LiF:F2− color center crystals, Cr4+: YAG crystals, RG1000 color glass filters, and the single crystal semiconductor saturable absorber wafers that are in developed
in our microchip laser systems. 相似文献
180.
Rebuilding of metal components with laser cladding forming 总被引:4,自引:0,他引:4
Laser cladding forming (LCF) is a novel powerful tool for the repairing of metal components. Rebuilding of V-grooves on medium carbon steel substrates has been carried out with laser cladding forming technique using stainless steel powder as the cladding material. Microstructure of the deposited layers has been characterized using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDAX), electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Mechanical properties of the rebuilt V-groove samples have been evaluated by tensile and impacting tests and microhardness measurement. Experimental results show that good fusion bonding between the rebuilt layers and the substrate has been formed, and the microstructure of the cladding layers is mainly composed of fine, dense and defect-free epitaxial columnar dendrites. Due to the effect of grain size refinement, the tensile strength, impacting toughness, elongation and microhardness of the rebuilt samples have been greatly enhanced compared to those of the substrate. Microhardness is also very uniform throughout the rebuilt regions. With the growth of the deposited layers, the microhardness increases gradually. The good ductility of the deposited regions is verified by the SEM fracture analysis. 相似文献