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소 수정란의 공배양 및 동결이 체외발생에 미치는 영향에 관한 연구
이종진,이명헌,남윤이,이만휘,이봉구,김상근 충남대학교 수의과대학 동물의과학연구소 1996 動物醫科學硏究誌 Vol.4 No.-
The studies on the carried out to investigate the effects of co-culture with cumulus cells and oviduct epithelial cells on the in vitro fertilization and cleavage rate of bovine follicular oocytes, and to determine the optimum thawing temperature and equilibration time of frozen bovine embryos and on survival rate and in vitro developmental rate of bovine embryos. The ovaries were obtained from slaughtered Korean native cows. The follicular oocytes were cultured in TCM-199 medium containing 10 IU/㎖의 PMSG(Sigma, USA), 10 IU/㎖의 hCG, 1 ㎍/㎖의 β-estradiol(Sigma, USA) and 10% FCS(Sigma, USA) for 24-48 hrs in incubator with 5% CO_2 in air at 38.5℃ and then matured oocytes were again cultured for 12-18 hrs with motile capacitated sperm by preincubation of heparin. The bovine embryos following dehydration by cryoprotective agents and a various concentrations of sucrose were directly plunged into liquid nitrogen and thawed in 30℃ water. The results are summarized as followes : 1. The in vitro fertilization and in vitro developmental rates of bovine oocytes co-cultured with cumulus cells in TCM-199 media were 75.0%-76.8% and 17.3%-27.6%, respectively. And in-vitro fertilization rates of cumulus-enclosed oocytes(55.4%) were significantly(p<0.05) higher than cumulus-denuded oocytes(23.1%). 2. The in vitro fertilization and in vitro developmental rates of bovine oocytes co-cultured with 1 ×10^4 cells/㎖, 1 ×10^6 cells/㎖, 1 ×10^8 cells/㎖ and 1 ×10^15 cells/㎖ oviduct epithelial cells in TCM-199 media were 74.5%-77.8% and 15.7%-21.2%, respectively. 3. The in-vitro fertilization and in vitro developmental rates of bovine oocytes co-cultured in TCM-199 media containing PMSG, hCG, PMSG + hCG, PMSG + β-estradiol, hCG + β-estradiol 0 to 40 hrs after insemination were 74.0%-77.4% and 18.9% - 23.1, respectively. 4. The survival rates of bovine embryos thawed after rapid freezing in the media containing various kinds of cryoprotective agents added 0.25M and 0.50M sucrose were 14.7% - 35.1% and 17.6% - 31.6%, respectively. The survival rates of bovine embryos thawed after rapid freezing in the freezing media containing a various concentration of sucrose added 1.5M and 2.0M glycerol, 1.5M and 2.0M DMSO, and 1.5M and 2.0M propanediol were 23.5% -31.4% and 20.6% - 34.1%, respectively. 5. The temperature thawed at 30℃ after rapid freezing of bovine embryos resulted in a significantly higher embryos survival rate than did at 20℃ and 35℃. 6. The equilibration time on the survival rates of bovine embryos was attained after short period of time(2.5-5 min.) in the freezing medium higher than ling period of time(10-20min.).
위성 통신용 6-pole 이중 모드 대역 통과 필터에 관한 연구
이명의,박헌중 한국기술교육대학교 1997 論文集 Vol.4 No.1
A synthesis procedure is presented for dual-mode bandpass waveguide cavity filter. Orthogonal modes in circular waveguide are employed to enable negative coupling elements to be realized. Design information is provided by the realization of a 6-pole elliptic function bandpass filter with TE₁₁₃ mode operating in a 40-MHz bandwidth centered at 12.27 GHz for KOREASAT downlink frequency. To demonstrate the validity of the design procedure, a waveguide bandpass filter has been constructed and measured. Experimental results show good agreement with the designed specifications.
Al-Sn 합금의 마찰 특성에 미치는 Sn 형상의 영향
李定根,朱大憲,金文鉉,金明鎬 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.10
Effects of Sn morphology on the friction and wear characteristics of Al-Sn alloys were investigated by using the tribology tester, optical microscope and scanning electron microscope. Three different types of Sn morphologies named elongated, small network and large network structure were obtained by cladding and heat treatment. Wear resistance of the specimen having large network structure exhibited better anti-friction characteristics compare to that of the elongated structure. Also specific wear rate and friction coefficient decreased markedly with change of Sn morphology from elongated to large network structure. Abrasive and adhesive wear occurred for the elongated structure, while oxidation wear was observed for the network structure.
한명철,김정관,최명욱,이왕근,김헌주 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-
The dental high-speed handpiece is one of the most popular and important devices that has been widely used as the main means of cutting tooth structure and restorative materials in dentistry, In consideration of usage and marketability of the dental handpiece, it is obviously worthy of investigating it. In this paper, a high speed dendal handpiece is developed through reverse engineering with 3D X-Ray CT equipment and wire cutter for the Mark II model in NSK. The demension of the handpiece parts is obtained through this process, and 3D modeling is performed with CATIA V5. The interference between parts can be examined through the part assembly in CATIA, and the performance is finally compared with Mark II model in NSK.
오염된 토양으로부터 분리된 세균에 이한 2,4-Dinitrotoluene과 2,6-Dinitrotoluene의 생물학적 제거
오계현,조윤석,이명석 순천향대학교 기초과학연구소 1999 순천향자연과학연구 논문집 Vol.5 No.2
Dinitrotoluenes (e.g., 2.,4-Dinitrotoluene and 2,6-Dinitrotoluene) are the major impurity resulting from the manufacture of 2,4,6-trinitrotoluene(TNT) and are primary starting materials for the synthesis of toluenediisocyanate which are used in the production of polyurethane foam. Both 2,4-DNT(2,4-dinitro- toluene) and 2,6-DNT(2,6-dinitrotoluene) are recalcitrant and have been shown to be toxic to aquatic and terrestrial organisms in the environment. Because little information is available for the biological degradation of DNTs, they have has not been evaluated for the possible treatment processes of industrial waste streams where DNTs may represent a serious disposal problem. In the present work, we explored the feasibility using a bacterium for DNTs degradation, with the ultimate aim of application for the industrial treatment. A DNTs-degrading bacterium was isolated from soil samples collected from an explosive contaminated area. Complete degradation of 2,4-DNT at the initial concentration of 50 ㎎ 2,4-DNT per liter was achieved within 10 days of incubation in bench-scale bioreactors, whereas 2,6-DNT degraded completely within 14 days under the same conditions, respectively. The bacterium was able to utilize DNTs as the sole nitrogen source. Co-substrate was essential for the bacterial growth and DNTs degradation in the medium. Neither bacterial growth nor DNTs degradation were observed in the absence of co-substrate. The detection of the parent substrates and their intermediates were based on HPLC and GC-MS methodology.
TNT-분해세균인 Stenotrophomonas maltophilia에 의한 s-Triazine계 제초제인 Atrazine의 미생물학적 분해
오계헌,조윤석,이명석 순천향대학교 기초과학연구소 1999 순천향자연과학연구 논문집 Vol.5 No.2
The agricultural use and relative persistence of s-triazine herbicide such as atrazine have led to increasing concern about environmental contamination. Stenotrophomonas maltophilia capable of utilizing TNT as sole nitrogen source has been isolated from contaminated soils and the bacterium showed excellent degradability for several-triazine herbicides including atrazine. Complete depletion of atrazine was achieved within 30 hours of incubation. Atrazine was catabolized in the presence of different supplemented carbons. Among the co-substrates used in this experiment (e.g., glucose, fructose, starch, succinate, acetate), fructose was the best co-substrate. However, no atrazine degradation was monitored without the supplemented co-substrates in the cultures. The relationships between atrazine degradation by S. maltophilia and several relevant physicochemical parameters (e.g., N-sources, yeast extract) were examined. High performance liquid chromatographic methodology was used to measure this substrate and it also resolved unknown intermediates.