http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Optical Technique to Measure Five-Degree-of-Freedom Error Motions for a High-Speed Microspindle
Hiroshi Murakami1,Norio Kawagoishi,Eiji Kondo,Akira Kodama 한국정밀공학회 2010 International Journal of Precision Engineering and Vol. No.
We present an optical technique to measure five-degree-of-freedom error motions of a high-speed microspindle. The measurement system consists of a rod lens, a ball lens, four divided laser beams, and multiple divided photodiodes. When the spindle rotates with its concomitant rotation errors, the rod and ball lenses, which are mounted to the chuck of the spindle, are displaced, and this displacement is measured using an optical technique. For this study, we decide the design parameters of the optical system using ray tracing, fabricate a prototype of the measurement system, and evaluate it experimentally. The results show that the measurement system has a resolution of 5 nm and can be used to evaluate high-speed microspindle rotation errors.
Surface Damage and Fatigue Strength of Ultrafine Grained Copper Treated by Mild Annealing
Teshima, N.,Goto, M.,Han, Seung Zeon,Euh, Kwang Jun,Yamauchi, K.,Kawagoishi, Norio Trans Tech Publications, Ltd. 2013 Key Engineering Materials Vol.577 No.-
<P>Fatigue tests of ultrafine grained (UFG) copper produced by equal channel angular pressing (ECAP) showed negligible enhancement of fatigue strength in high-cycle fatigue regime. This was attributed to the thermal instability of UFG microstructure; a grain coarsening occurred during a large number of stress repetitions. Aiming at an enhancement of fatigue strength in the long-life field in excess of 10<SUP>7</SUP>cycles, post-ECAP mild-annealing for improving thermal stability was conducted. Grains with sizes up to a few tens of micrometers surrounded by fine grains were formed after the annealing as a result of discontinuous recrystallization. The improved stability of post-ECAP annealed micrstrucvture was related to the 9% increased fatigue strength in long life fields. The effect of bimodal microstructure on surface damage formation and fatigue strength was discussed.</P>
Tensile Properties and Fatigue Strength of Ultrafine Grained Pure Copper
Goto, Masahiro,Han, Seung Zeon,Kim, Sang Shik,Kawagoishi, Norio,Lim, Cha Yong Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.353-358 No.3
<P>Oxygen-free copper was processed by equal channel angular pressing with different numbers of ECAP process cycles, NP. Tensile strength was increased with an increase in NP, but it tended to saturate after NP = 4. Conversely, elongation was dramatically decreased by first pressing, but it tended to saturate up to NP = 3, followed by slight increasing trend after NP = 4. Fatigue tests of specimens processed with NP = 4 and 8 were performed. The change in surface morphologies during fatigue was monitored successively. In addition to this, the change in surface hardness was measured. Significant decrease in surface hardness due to cyclic stresses was measured. The physical basis of fatigue damage of UFG copper was discussed based on the experimental results.</P>