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Al첨가에 의한 무수축 Mullite-$ZrO_2$ 요업체의 제조에 관한 연구
김정욱,김일수,Kim, Jeong-Uk,Kim, Il-Su 한국재료학회 1995 한국재료학회지 Vol.5 No.7
Al 금속분말을 zircon sand (ZrSiO$_4$)와 A1$_2$O$_3$혼합체에 첨가하여 반응소결시킴으로써 무수축 Mullite-ZrO$_2$, 요업체를 얻고자 하였다. 반응식, 3(Al+Al$_2$O$_3$)+2ZrSiO$_4$$\longrightarrow$3A1$_2$O$_3$ .2SiO$_2$+2ZrO$_2$에 의하여 ZrO$_2$-강화 Mullite 요업체를 제조하였다. Al 분말은 A1$_2$O$_3$에 대해 0-30 무게 퍼센트까지 대체하였다. 평량한 분말을 볼밀하여 혼합 분쇄한 후, 정수압 성형하여 시편을 제조하고, 온도범위 1450-1$600^{\circ}C$에서 3시간 반응소결시켰다. Al의 충분한 산화를 위해, 한편으로는 125$0^{\circ}C$에서 5시간동안 열처리를 거친후 소성온도로 올리기도 했다. Al을 첨가함으로서 반응은 촉진되었으며, 소성수축도 산화한 Al의 부피팽창에 의해 상쇄되어, 무수축요업체 제조의 가능성을 보였다. 박편모양을 한 비교적 큰 Al분말이 잘 분쇄되지 않음으로 해서, Al이 자리했던 곳에 큰 기공을 남겼다. In this paper the manufacture of shrinkage-free in situ Mullite-ZrO$_2$ceramics through the addition of Al base metal powder to the mixture of ZrSiO$_4$and A1$_2$O$_3$was attempt. The ZrO$_2$-strengthened mullite ceramics was prepared after the following reaction form, 3(Al+Al$_2$O$_3$)+2ZrSiO$_4$longrightarrow3A1$_2$O$_3$.2SiO$_2$+2ZrO$_2$Al metal powder was added from none to 30 weight percent to the A1$_2$O$_3$. The powders were mechanically mixed, isostatically pressed and reaction sintered at 1450-1$600^{\circ}C$ for 3hours. The specimens were sintered with and without intrim soaking time for 5 hours at 125$0^{\circ}C$ for the oxidation of Al-powder The addition of aluminium accelerates the reaction and compensate the shrinkage during the sintering through an increase in volume of oxidized Al. Because coarse flake type Al metal powders were not effectively milled, oxidized Al resulted in the relative large pore in the specimen.
일반적인 체외수정 방법과 세포질내 정자주입술로 얻어진 배아의 동결-융해 후 이식의 결과
김정욱,한미현,변혜경,전진현,손일표,궁미경,백은찬,강인수,이호준,Kim, Jeong-Wook,Han, Mi-Hyun,Byun, Hye-Kyung,Jun, Jin-Hyun,Son, Il-Pyo,Koong, Mi-Kyoung,Paik, Eun-Chan,Kang, Inn-Soo,Lee, Ho-Joon 대한생식의학회 1997 Clinical and Experimental Reproductive Medicine Vol.24 No.1
Intracytoplasmic sperm injection (ICSI) recently has been utilized widely as the most successful technique to overcome the unfertilization problem in cases of severe male infertility in couples who could not be treated by conventional IVF. Recently, indications of ICSI have been extended further and more fertilized oocytes become available. Thus, it is necessary to examine the efficiency of freezing the surplus embryos obtained from ICSI. We compared the survival rate and the future outcome of cryopreserved embryos obtained either after conventional IVF or ICSI during the same period. After ICSI or IVF, five best-quality embryos from each patient were transferred in the stimulation cycle and the surplus pronuclear (PN) stage oocytes or multicellular embryos were cryopreserved by slow freezing protocol with 1,2-propanediol (PROH) as a cryoprotectant. A total of 792 embryos from ICSI trial were thawed and 65.2% (516/792) survived. The survival rates of PN stage oocyte, multicellular embryo and PN + multicellular embryo were 63.5%, 68.2%, 64.0%, respectively. After 111 transfers, 34 pregnancies were achieved, corresponding to a clinical pregnancy rate of 30.6% per transfers. We thawed 1033 embryos from IVF trials and 57.5% (594/1033) survived. In IVF cycle, the survival rates of PN stage oocyte, multicellular embryo and PN + multicellular embryo were 58.2%, 65.2%, 40.2%, respectively. Thirty eight clinical pregnancies were established after 134 transfers, corresponding to a pregnancy rate of 28.4% per transfer. The cleavage rate of thawed PN stage oocytes from ICSI trial (61.3%) was significantly higher than those from conventional IVF (53.4%). The developmental rates of good embryo (${\geqq}$ grade II) in thawed PN stage oocytes obtained from conventional IVF and ICSI were 63% and 65%, respectively. We concluded that PN stage oocytes, multicellular embryos resulting from ICSI procedure can be successfully frozen/thawed with reasonable clinical pregnancy rates comparable to those of IVF.
위팔두갈래근의 긴갈래와 짧은갈래의 팔굽관절 굽힘 각도에 따른 근활성도 분석
김정욱,박민철,Kim, Jeong-Wook,Park, Min-Chull 대한고유수용성신경근촉진법학회 2020 PNF and Movement Vol.18 No.1
Purpose: This study aimed to investigate the impact of resistance on the muscle activities of the long and short heads of the biceps brachii, according to the elbow angle in supination, and the difference in muscle activity between the long and the short heads. Methods: This study was conducted with 22 men in their 20s who voluntarily agreed to participate. With the glenohumeral joint neutral in a position of supination, the elbow angle was randomly moved to 0°, 30°, 60°, and 90°. Using an 8-channel surface EMG while the participants held a 2-kg. dumbbell, the muscle activities of the long and the short heads of the biceps brachii were measured. The measured data were statistically processed using SPSS for Windows 12.0. For the activities of the short and the long heads according to the angle, a one-way ANOVA was conducted, and subsequently, to check the results of an analysis of the difference between groups, an LSD post-hoc test was conducted. An independent t-test was used to compare the activities of the long head and the short head according to the angles. Results: The analysis of the impact of the load of the dumbbell at each elbow angle on the muscle activities of the long and short heads of the biceps brachii revealed significant differences in both heads (p < 0.05). The result of the post-hoc analysis showed significant differences in both heads at angles between 0° and 30°, between 0° and 60°, and between 0° and 90°. Analysis of the impact of the load of the dumbbell in supination on the muscle activities of the long and short heads showed a significant difference at the angle between 0° and 30° (p < 0.05). Conclusion: The long head of the biceps brachii mainly acts in supination; however, in supination at elbow-bending angles of 60° and 90°, there was no difference in muscle activity between the short head and the long head.
동결수정란 이식주기에서 수정란 융해 후 생존율과 임신율에 영향을 미치는 요인
김정욱,변혜경,염혜원,전진현,박용석,송인옥,송지홍,최범채,궁미경,전종영,강인수,Kim, Jeong-Wook,Byun, Hye-Kyung,Youm, Hye-Won,Jun, Jin-Hyun,Park, Yong-Seog,Song, In-Ok,Song, Ji-Hong,Choi, Bum-Chae,Koong, Mi-Kyoung,Jun, Jong-Young,Kang, 대한생식의학회 2000 Clinical and Experimental Reproductive Medicine Vol.27 No.1
Objective: The purpose of this study was to determine the important factors affecting survival and pregnancy rate in frozen-thawed embryo transfer cycles. Methods: we performed retrospective analysis in 738 cycles of frozen-thawed embryo transfers, in relation to the insemination methods, the freezing stage of embryo, patient's age, infertility factors and the origin of injected sperm in ICSI cycles. After conventional IVF or ICSI, the supernumerary PN stage zygotes or multicellular embryos were cryopreserved by slow freezing protocol with 1,2-propanediol (PROH) as a cryoprotectant. Results: The survival rates of thawed embryos were 69.3% (1585/2287) in conventional IVF group and 71.7% (1645/2295) in ICSI group. After frozen-thawed embryo transfers, 27.0% (92/341) and 32.0% (109/341) of pregnancy rates were achieved in conventional IVF and ICSI group, respectively. There were no significant difference in the survival and pregnancy rates according to the insemination methods, the freezing stage and patient's age. However, the pregnancy rate (36.2%) of male factor infertility was significantly higher than the tubal (27.2%) and other female factor infertility (22.9%). In ICSI group, the origin of injected sperm did not affect the outcome of frozen-thawed embryo transfer cycles. Conclusion: The present study demonstrates that acceptable clinical outcomes can be achieved after the transfer of frozen-thawed embryos regardless of the stage of embryos for freezing, the patient's age and the origin of injected sperm.