激光熔铸纳米碳管/铝基复合材料的工艺参数

采用激光熔铸工艺制备多壁纳米碳管（MWNTs）增强纯铝复合材料，研究不同铸模条件和激光工艺参数对复合材料熔铸缺陷和组织结构的影响。结果表明：在相同的激光工艺条件下，石墨铸模中激光熔铸的复合材料熔铸缺陷少，组织均匀细小；在相同的激光功率和铸模条件下，扫描速度为60mm/min时，熔铸的复合材料的熔铸缺陷最少，组织最均匀细小。     

混合式光电电流互感器高压侧的电源方案研究

混合式光电电流互感器(HOCT)高压侧供电方案一直是HOCT技术实用化、产业化的一个关键和难点。该文介绍了HOCT的基本原理、结构并给出了几种HOCT高压侧的供电方案,对各种方案进行了比较评价,指出了各种方案在使用中的优劣,为高压侧供电方案实用化、产业化进行了有益的探讨。     

Microstructure and abrasion wear behavior of Ni-based laser cladding alloy layer at high temperature

Ni-based alloy coating on 21-4-N heat-resistant steel was prepared using CO2 laser, and the high-temperature abrasion wear was tested. The microstructure of this cladding layer and its abrasion wear behavior at high temperature by changing compositions and temperatures were investigated by means of optical microscope and scanning electron microscope. Among the three compositions of cladding layer, i.e. Ni21 ＋20% WC＋0. 5 % CeO2, Ni25＋20 % WC＋0. 5 % CeO2 and Ni60 ＋ 20 % WC ＋ 0. 5 % CeO2, the experimental results show that Ni21 ＋ 20 % WC ＋ 0.5?O2 cladding layer is made up of finer grains, and presents the best abrasion wear behavior at high temperature. The wear pattern of laser cladding layer is mainly grain abrasion at lower temperature, and it would be changed to adhesive abrasion and oxide abrasion at higher temperature.     

高测速双频激光干涉仪及其性能检测

新型驱动电机和高速传动器件的发展使得数控机床和三坐标测量机等的运行速度已经达到1000mm/s，而目前商用外差干涉仪的测量速度不能完全满足这一要求。为此，研制了一种基于5MHz频差双频激光器的高测速干涉仪，理论上的最高测量速度可达1580mm／s。通过实验对测量速度和计数频率进行了检测，结果证明，这种干涉仪可以达到的最高测量速度为980mm／s，外触发计数频率达11kHz。     

PTB所建激光干涉振动一次绝对校准标准简析

按照ISO/16063-11：1999《激光干涉绝对法振动校准》所述,激光干涉振动一次绝对校准方法主要有条纹计数法、最小点法与正弦逼近法三种,其复现频率范围为1Hz～10kHz.而德国联邦物理技术研究院（PTB）现已建立和保存的低频、中频、高频振动激光干涉一次绝对校准标准的复现频率范围则达0.1Hz～20kHz.此外,PTB还实现了旋转运动物理量值--角加速度的复现;其复现频率范围也达到0.3Hz～1kHz.作为曾在PTB1.22实验室进行过研究工作的访问学者,作者旨在通过对PTB所建激光干涉振动一次绝对校准标准的     

Preparation of Neodymium-Doped Yttrium Aluminum Garnet Transparent Ceramics by Homogeneous Precipitation Method

Neodymium-doped yttriumaluminumgarnet(Nd∶YAG)transparent polycrystalline ceramics,laser ce-ramic matrix materials,are gradually becomingsubsti-tutes for single crystals because they are provided withpredominantly chemical stability,highly doped ionconcentration,excellent optical performance and hightemperature stability[1,2].Presently,the conventionallyused methods to produce Nd∶YAG powders are solid-state processes[3],chemical precipitation methods[4,5]andlowtemperature combustiontechniqu…     

Antibacterial Characteristics of ZnO-CeO2 Nano-Powder Prepared by Laser Vapor Condensation

Microbialpollutionandcontaminationbymicroor ganismshaveproducedvarioustroublesinindustryandothervitalfields ,suchasdegradationandinfec tion .Thenewpasteurizationandantibacterialtech niqueshavebeendemandedandstudied[1] .Inrecentyears ,therareearthmetaloxid…     

空区立体测量方法初探

对 3种井下空区立体测量方法进行分析对比,结合本公司实际情况推荐一种可行而有效的测量方法,即井下空区激光测量系统。     

可调焦激光水准仪的研制和应用

研制了可调焦激光水准仪,介绍了其结构和性能。利用自行研制的多台可调焦激光水准仪,完成了KrF激光MOPA光学角多路系统中的多项调整测试工作。同时介绍了该仪器在其它光学设备调试中的应用。     

Stimulus Selectivity of Figural Aftereffects for Faces.

Viewing a distorted face induces large aftereffects in the appearance of an undistorted face. The authors examined the processes underlying this adaptation by comparing how selective the aftereffects are for different dimensions of the images including size, spatial frequency content, contrast, and color. Face aftereffects had weaker selectivity for changes in the size, contrast, or color of the images and stronger selectivity for changes in contrast polarity or spatial frequency. This pattern could arise if the adaptation is contingent on the perceived similarity of the stimuli as faces. Consistent with this, changing contrast polarity or spatial frequency had larger effects on the perceived identity of a face, and aftereffects were also selective for different individual faces. These results suggest that part of the sensitivity changes underlying the adaptation may arise at visual levels closely associated with the representation of faces. (PsycINFO Database Record (c) 2010 APA, all rights reserved)