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Methylphosphonicdifluoride의 가수분해 및 가수분해 생성물로부터 HF의 회수 연구
이종철,이용한,박훈,최승주 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.4
Methylphosphonicdifluoride(DF)의 최적 가수분해 조건을 찾기 위하여 염기성 및 중성 수용액에서 가수분해하고 가수분해 생성물로부터 F 화합물을 분리, 회수하였다. DF는 NaOH 수용액의 농도 6 mole, [OH]/[DF]의 비율 4 이상에서 5분 내에 80%가 분해된 반면, 중성 수용액에서는 H₂O/DF의 부피 비 1.5 이상에서 93-97%의 분해율을 보였다. 가수분해 후 생성물중의 HF를 분리하기 위하여 수산화칼슘을 사용하였으나 생성입자의 크기가 매우 작고 겔 상태로 존재하여 HF의 완전분리가 곤란하였다. 반면, 중성 수용액에서 가수분해한 DF의 생성물은 MPA, HF 및 미량의 methylphosphonofluoridic acid(MF)가 존재하였다. MPA는 휘발성이 없는 흡습성 고체이고 HF는 물과 공비점을 형성 하므로 물을 주기적으로 반응기에 공급하면서 반복 증류하여 HF를 용이하게 분리 할 수 있었다. 가수분해 생성물을 증류 한 결과 최대 99.7%의 F 이온을 분리하였으며 증류 후 회수된 불산의 최종 농도는 20% 이었다. The hydrolysis of methylphosphonicdifluoride(DF) both in NaOH solutions and neutral waters was studied to find optimum reaction conditions. Separation of F ions from the reaction products was also conducted. The destruction efficiency of DF in NaOH solutions was above 80% in five minutes at the mole ratio of [OH]/[DF]3-6, while the efficiency of 93-97% was obtained in water when the volume ratio of the H₂O/MPD was above 1.5. Ca(OH)₂ was added to to remove HF in the product solutions after DF hydrolysis in alkaline solutions but it was not easy to remove due to coagulation of the products. On the other hand, HF was easily separated by repeated distilation adding water periodically to the reactor from the reaction products of DF hydrolysis in water, 99.7% of the total fluoride ions were removed from the products by repeated distillation. The final concentration of HF solution recovered was 20wt%.
박종태,최영곤,한남익,박철용,표내숙,조춘호 釜山大學校 附設 體育科學硏究所 1998 體育科學硏究所 論文集 Vol.14 No.-
In the early decades of this century, Charisma which originally means endowment with the gift of grace, has been introduced to social sciences by German sociologist, Max Weber. It quickly became interested in the field of sociology and politics. But, into the 1970s, charismatic leadership still had not became a subject for empirical or experimental research related to organizational theory. Recently, much attention has been paid to charismatic leadership as the prototype of leadership that people have in mind when they describe their ideal leader and is more likely to provide a role model with which subordinates want to identify. As a result, in will perform further study related to Charisma leadership which developing various kind of measurement and instrument. Finally, it should identify lost of possibility and phenomenon through the study of charisma leadership.
사람폐암세포주 (PC-14)에서 Cyclosporin A에 의한 Adriamycin 내성의 극복
김영환,홍원선,송재관,강윤구,이진오,강태웅,김건열,한용철 대한내과학회 1990 대한내과학회지 Vol.38 No.3
Cyclosporin A and verapamil were tested using MTT assay to evalute the modification effect on the resistance to adriamycin in a human lung cancer cell line(PC-14) and its resistant subline(PC-14/A). PC-14/A was derived by the continuous exposure of PC-14 to incremental concentrations of adriamycin. PC-14/A was 2.5 times more resistant to adriamycin in terms of ICso than PC-14. Cyclosporin A alone, at a concentration of 2.5㎍/㎖, inhibited the growth of PC-14 to 68.3%. 2.5㎍/ ㎖ and 5.0㎍/㎖ of cyclosporin A showed an increase in the cytotoxicity of adriamycin (p<0.01) with 5.0㎍/㎖ being greater than 2.5㎍/㎖(p<0.01). Excluding the direct cytotoxic effect, however, cyclosporin A did not increase in the sensitivity of PC-14 to adriamycin but only showed an additional cytotoxic effect with adriamycin. Verapamil (up to 6.0㎍/㎖) did not inhibit the growth of PC-14. 3.0㎍/㎖ of verapamil did not increase the cytotoxic effect of adriamycin. The combination of cyclosporin A and verapamil with adriamycin enhanced the cytotoxicity of adriamycin, but the result was similar to that of cyclosporin A with adriamycin. 5.0㎍/㎖ of cyclosporin A modified the adriamycin resistance of PC-14/A(SR, 3.2). However, 3.0㎍/㎖ of verapamil did not significantly reverse the adriamycin resistance of PC-14/A. The modified effect of the combination of 5.0㎍/㎖ of cyclosporin A and 3.0㎍/㎖ of verapamil was similar to that of 5.0㎍/㎖ of cyclosporin A alone in PC-14/A. These results demonstrate that cyclosporin A has an additional cytotoxic effect with adriamycin in PC-14 and PC-14/A and has overcome the acquired resistance to adriamycin in PC-14/A. They also suggest that cyclospoin A may have the therapeutic potential in the treatment of human lung cancer.