선형레이저로 계측한 모르타르소재기반 적층 비드 형상 안정성평가

박진수(J. S. Park),이상환(S. H. Lee),오지원(J. W. Oh),최한신(H. S. Choi) Korean Society for Precision Engineering 2020 한국정밀공학회 학술발표대회 논문집 Vol.2020 No.9월

스테레오 비전과 가속 및 자기센서를 이용한 수술도구 추적 시스템 연구

김석중(S. J. Kim),장민호(M. H. Chang) 한국정밀공학회 2014 한국정밀공학회 학술발표대회 논문집 Vol.2014 No.10월

SC 전용 보호계전기 개발

정재기(J. K. Jeong),윤시영(S. Y. Yun),김석중(S. J. Kim),김근규(K. G. Kim) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.5

SC(Static Condenser) in KEPCO is used in voltage control and power factor compensation. Currently KEPCO uses SC to 154㎸ 50MVA and 23㎸ 5MVA. It is not important in old days, because a SC bank accident has no effect on power system. But we are interested in the SC bank for power quality in these days. The SC Bank has a reactor and a condenser using series connection. It is operated in critical point for resonance circuit normally. Therefore the SC bank has a small reliability against other power instruments. If a 4th harmonic frequency as a resonance frequency is supplied in system, the condenser is damaged because of a resonance current. And a trip and a closing for CB(Circuit Breaker) in many times will have a big influence of SC bank destruction. General OCR(Over Current Relay) observing SC bank is not useful for this protection. We think that protection relay must be have the SC bank characteristics. A solution for this problem is active power, resonance frequency and impedance.

광 픽업 구동기의 최적설계에 관한 연구

김선모(S.M.Kim),김석중(S.J.Kim),이용훈(Y.H.Lee) 한국소음진동공학회 2001 한국소음진동공학회 학술대회논문집 Vol.2001 No.11

비정상적 정자형성 환자의 정소에서 Heat Shock Protein A2 (hspA2) mRNA 발현의 감소

손원영,황서하,한징택,이재호,김석중,김영찬,Son, W.Y.,Hwang, S.H.,Han, C.T.,Lee, J.H.,Kim, S.J.,Kim, Y.C. 대한생식의학회 1999 Clinical and Experimental Reproductive Medicine Vol.26 No.1

Objective: Heat shock protein 70-2 (Hsp70-2) gene knockout mice are found to have premeiotic arrest at the primary spermatocyte stage with a complete absence of spermatids and spermatozoa. This observation led to the hypothesis that hspA2 may be disrupted in human testes with abnormal spermatogenesis. To test this hypothesis, we studied the mRNA expression of hspA2 in infertile men with azoospermia. Design: The mRNA expression were analyzed by competitive RT-PCR among testes with normal spermatogenesis, pachytene spermatocyte arrest, and sertoli-cell only syndrome. Materials and methods: Testicular biopsy was performed in men with azoospermia (n=15). Specimens were subdivided into three groups: (group 1) normal spermatogenesis (n=5), (group 2) spermatocyte arrest (n=5), (group 3) Sertoli-cell only syndrome (n=5). Total RNA was extracted by Trizol reagent. Total extracted RNA was reverse transcribed into cDNA and amplified by PCR using specific primers for hspA2 target cDNAs. A competitive cDNA fragment was constructed by deleting a defined fragment from the target cDNA sequence, and then coamplified with the target cDNA for competitive PCR. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene was used as an internal control. Results: On Competitive RT-PCR analyses for hspA2 mRNA, significant amount of hspA2 expression was observed in group 1, whereas a constitutively low level of hspA2 was expressed in groups 2 and 3. Conclusion(s): The study demonstrates that the hspA2 gene expression is down-regulated in human testes with abnormal spermatogenesis, which in turn suggests that hspA2 gene may play a specific role during meiosis in human testes.

인간 조직에서 Heat Shock Protein A2 (HspA2) 단백질의 발현

손원영,황서하,한징택,이재호,최윤정,김석중,김영찬,Son, W.Y.,Hwang, S.H.,Han, C.T.,Lee, J.H.,Choi, Y.J.,Kim, S.,Kim, Y.C. 대한생식의학회 1999 Clinical and Experimental Reproductive Medicine Vol.26 No.2

In mouse, the heat shock protein 70-2 (hsp70-2) is found to have special function in spermatogenesis. Based on the observation, the hypothesis that human hspA2 (human gene; 98.2% amino acid homology with hsp70-2) might have important function in spermatogenesis in human testes was proposed. To test the hypothesis, we examined the expression of hspA2 in human tissues. Expression vector pDMC4 for expression of the human hspA2 protein using pTricHisB (invitrogen, USA) was constructed and the expressed hspA2 protein was cross-reacted with antiserum 2A raised against mouse hsp70-2 protein. Based on the cross-reactivity, we determined the expression level of hspA2 protein in human tissues by western blot analysis using the antiserum 2A. We demonstrated that antiserum 2A antibodies detected human hspA2 protein with specificity which was produced in the E.coli expression system. On Western blot analyses, significant hspA2 expression was observed in testes with normal spermatogenesis, whereas a low level of hspA2 was expressed in testis with Sertoli-cell only syndrome. Also, a small amount of hspA2 was detected in breast, stomach, prostate, colon, liver, ovary, and epididymis. These results demonstrate that the hspA2 protein is highly expressed in male specific germ cells, which in turn suggests that hspA2 protein might playa specific role during meiosis in human testes as suggested in the murine model. However, further studies should be attempted to determine the function of hspA2 protein in human spermatogenesis.

초음파 측정에 의한 한우의 도체육량 예측

이용준,전기준,최성복,석홍기,김석중,이성기,송영한 한국동물자원과학회 2003 한국축산학회지 Vol.45 No.2

본 시험은 초음파를 이용한 한우의 도체육량등급 예측율을 향상시키기 위하여 24개월령 거세한우 573두를 대상으로 출하직전에 체중측정과 함께 실시간 초음파 진단기를 이용하여 도형체질을 측정하였다. 초음파 측정치와 도체실측치와의 비교분석에서 도출된 다양한 육량예측 기법을 이용하여 도체육량등급을 예측하였고, 그 결과를 요약하면 다음과 같다. 등지방 두께와 배최장근 단면적의 도체 실측치와 초음파 측정치간의 차이는 각각 0.6±1.65mm와 0.7±5.56㎡로 나타났다. 등지방 두께 및 배최장근 단면적의 초음파 측정치와 도체 실측치간의 상관계수는 각각 0.86 및 0.82로 높게 나타났다(p<0.001). 도체육량등급 예측율은 육량지수 산식, 등지방 보정식, 중회귀 분석 및 의사결정나무 분석에서 각각 80.3%, 81.3%, 80.1% 및 81.8%를 보여, 의사결정나무 분석이 예측율과 활용성이 가장 높은 것으로 나타났다. This study was conducted to predict the carcass yield traits using ultrasound before slaughter and to enhance the prediction accuracy of carcass yield grade by applying various strategies. For this experiment, five hundred seventy three Hanwoo steers of 24 months of age were used. Difference between ultrasound results and carcass measure of BFT and LMA was 0.6±1.65㎜ and 0.7±5.56㎤, respectively. Correlation coefficient between ultrasound result and carcass measure of BFT and LMA was 0.86 and 0.82 respectively (p<0.001). Results for improving predictions of yield grade by four methods0the Korean yield grade index equation, fat depth alone, regression and decision tree methods were 80.3%, 81.3% 80.1% and 81.8%, respectively. We conclude that the decision tree method can easily predict yield grade and is also useful for increasing prediction accuracy rate.

초음파를 이용한 한우 육량등급의 조기예측

이용준,석홍기,김석중,송영한 한국동물자원과학회 2003 한국축산학회지 Vol.45 No.2

본 시험은 초음파를 이용하여 한우의 도체형질을 조기에 예측하기 위하여 거세한우 66두를 대상으로 18, 21 및 24개월령에 도체형질을 측정하고, 중회귀 분석 및 의사결정나무 분석을 이용하여 24개월령 출하시 도체형질을 예측하였다. 그 결과를 요약하면 다음과 같다. 도체육량등급에 따라 군을 분류하고 성장에 따른 도체형질의 변화를 관찰한 결과, 등지방 두께는 전기간에 걸쳐 각 도체육량등급간에 유의적 (p<0.05)인 차이를 보이며 A, B, C등급 순으로 얇게 나타났다. 중회귀 분석에 의한 도체육량등급의 예측율은 18, 21 및 24개월령에서 각각 78.8%, 86.4%, 및 90.9%를 나타냈으며, 의사결정 나무 분석에 의한 도체육량등급 예측율은 각 개월령에 따라 78.8%, 89.4% 및 89.4%를 나타냈다. This study was carried out to make early prediction of carcass yield grade. Sixty six Hanwoo steers were measured for back thickness, longissimus muscle area and body weight at 18, 21 and 24 months of age by ultrasound. Carcass evaluation was done after ultrasound measurement at 24 month of age. Ultrasonic yield grade at 18, 21 and 24 month of age were predicted by regression and decision tree methods. Classifying by carcass yield grade, ultrasonic back fat thickness at 18, 21 and 24 months of age was significantly different in each carcass yield grade (p<0.05). The prediction accuracy of carcass yield grade by regression method was 78.8% at 18 months, 86.4% at 21 months and 90.9% at 24 months of age. By using the decision tree method for carcass yields grade, 78.8%, 89.4% and 89.4% of prediction accuracy were obtained at 18, 21 and 24 months of age, respectively.