The development of machining technology has coincided with the recent development of a diverse amount of materials and tools. The developed materials largely consist of hardened steel for vehicle and the mechanical industry. The machining of the hardened steel is performed in a lathe and many kind of machining centers, but it is difficult to machine because its hardness is the most difficult-to-cut materials. Hard-turning is a kind of machining process which omits the final grinding process and replaces it with a single accurate cutting process. In this paper, the turning of SKD 11(HRC 58) was performed using the CBN tool in order to recognize the optimum process conditions. The cutting force, tool life and wear, surface roughness were measured. Examining the machining characteristics when cutting of high hardened steel, low cutting speed and high conveying speed were identified to be effective in cutting conditions of SKD 11. Tool life was most effective in the conditions with 65m/min of cutting speed and 0.193mm/rev of feedrate and approximately 0.5um of very good surface profile was acquired at 0.079mm/rev of feedrate. Therefore, when cutting with Low CBN tool, it could be considered to be sufficient in reducing the steps of precision machining or replacing the polishing

As a pore precursor, carbon black with different content of 0 to 60 vol% were added to (Ba,Sr) powder. Porous (Ba,Sr) ceramics were prepared by pressureless sintering at for 1h under air. Effects of carbon black content on the microstructure and PTCR characteristics of porous (Ba,Sr) ceramics were investigated. The porosity of porous (Ba,Sr) ceramics increased from 6.97% to 18.22% and the grain size slightly decreased from to with increasing carbon black contents. PTCR jump of the (Ba,Sr) ceramics prepared by adding carbon black was more than , and slightly increased with increasing carbon black. The PTCR jump in the (Ba,Sr) ceramics prepared by adding 40 vol% carbon black showed an excellent value of , which was above two times higher than that in (Ba,Sr) ceramics. These results correspond with Heywang model for the explanation of PTCR effect in (Ba,Sr) ceramics. It was considered that carbon black is an effective additive for preparing porous based ceramics. It is believed that newly prepared (Ba,Sr) cermics can be used for PTC thermistor.

1. Background and Purpose For many years, Sibimikwanjungtang, Yangkyeoksanhwatang and Hyeongbangsabaeksan have been used as a therapeutic agent in constitutional disease. The effects of three prescriptions on the vascular system is not well-known. The purpose of this study is to determine the effects of these prescriptions on blood pressure(BP) and regional cerebral blood flow(rCBF). 2. Methods I injected a vein of rat with extracts of Sibimikwanjungtang, Yangkyeoksanhwatang and Hyeongbangsabaeksan with five kinds of dose and measured BP and rCBF. 3. Results After injected Sibimikwanjungtang, BP was not changed but rCBF was increased in a dose-dependent manner. After injected Yangkyeoksanhwatang, BP was elevated and rCBF was increased in a dose-dependent manner. After injected Hyeongbangsabaeksan, BP was not changed but rCBF was increased in a dose-dependent manner.