승모판막질환에 병발한 동맥색전증의 치험 1례

허용,김병열,이홍섭,김주이,이정호,유회성,Hur, Y.,Kim, B.Y.,Lee, H.S.,Kim, J.E.,Lee, J.H.,Yu, H.S. 대한흉부심장혈관외과학회 1980 Journal of Chest Surgery (J Chest Surg) Vol.13 No.1

We present one case of 26-year-old male having saddle block combined with mitral valvular disease [NYHA Class IV] with auricular fibrillation. The most common cause of emboli is atrial fibrillation. The clinical manifestations of saddle emboli are relatively slow due to development of collateral circulation and large size of lumen of the aorta. The 5month duration of saddle emboli in this case led to severe atrophic changes, coldness, peripheral cyanosis on the both lower extremities, and flexion deformity on the knee and ankle joint of the left lower extremity. We planned staged operation for the saddle block and for mitral stenoinsufficiency and tricuspid insufficiency, because of poor general condition of the patient. The thromboembolectomy of aortic bifurcation was performed through the transabdominal approach without trial of Fogarthy catheter embolectomy, because of expectation of the secondary inflammatory changes of the vessel wall and thrombi which was 3 cm X 1 cm X 0.5 cm in size with irregular surfaced solid in consistency. 1 month later, after thromboembolectomy, mitral valve replacement and tricuspid annuloplasty were performed, with successful early operative result. During operation organized thrombi [1 cm X 0.5 cm] in the left auricle was removed. We wonder if simple management using Fogarthy catheter might be possible to remove the thromboemboli instead of thromboembolectomy by aortotomy in this case.

무선채널의 협대역화에 따른 변조방식 고찰

박상영,이홍섭,Park, S.Y.,Lee, H.S. 한국전자통신연구원 1994 전자통신동향분석 Vol.9 No.4

최근 무선통신의 활성화에 따라, V/UHF(very/ultra high Frequency) 대역에서 한정된 주파수를 효율적으로 이용하기 위한 방법의 하나로서, 점차 점유 주파수 대역의 폭을 축소하여 보다 많은 이용자를 수용하도록 무선 채널의 협대역화가 추진되고 있다. 본 고에서는 먼저 V/UHF 대역 무선 통신에서 채널의 협대역화에 관련된 기술 중에서 현재까지 사용되고 있는 FM(frequency modulation), AM(amplitude modulation) 변조 방식의 장,단점을 살펴본후, 새로운 LM(linear modulation) 변조 방식에 대한 기술적 배경 및 특성을 알아보았다. LM은 SSR(single side band)-AM이 발전한 것으로서, TTIB(transparent tone-in-band), CLT(Cartesian loop transmitter), FFSR(feed-forward signal regeneration), DSP(digital signal processing)등 4가지의 기술이 결합하여 만들어진 것이다. LM 방식에 사용된 4가지 기술을 소개하고, 기존의 변조 방식에 비해 개선된 사항에 대해 서술한다.

인장변형에 따른 그래핀복합 카본블랙전극의 저항변화연구

이태원,이홍섭,박형호,Lee, T.W.,Lee, H.S.,Park, H.H. 한국마이크로전자및패키징학회 2015 마이크로전자 및 패키징학회지 Vol.22 No.1

Stretchable electrode materials are focused to apply to flexible device such as e-skin and wearable computer. Used as a flexible electrode, increase in electrical resistance should be minimalized under physical strain as bend, stretch and twist. Carbon black is one of candidates, for it has many advantages of low cost, simple processing, and especially reduction in resistivity with stretching. However electrical conductivity of carbon black is relatively low to be used for electrodes. Instead graphene is one of the promising electronic materials which have great electrical conductivity and flexibility. So it is expected that graphene added carbon black may be proper to be used for stretchable electrode. In this study, under stretching electrical property of graphene added carbon black composite electrode was investigated. Mechanical stretching induced cracks in electrode which means breakage of conductive path. However stretching induced aligned graphene enhanced connectivity of carbon fillers and maintained conductive network. Above all, electronic structure of carbon electrode was changed to conduct electrons effectively under stretching by adding graphene. In conclusion, an addition of graphene gives potential of carbon black composite as a stretchable electrode. 신축성 전극소재는 웨어러블 밴드나 전자피부와 같은 플렉서블 제품으로의 적용 때문에 주목 받고 있다. 플렉서블 소자로서 사용하기 위해선 구부리거나 비틀거나 늘리는 등 물리적 변형에도 전기저항의 증가가 최소화되어야 한다. 카본블랙은 저가의 간단한 공정, 특히 인장 시 비저항의 감소라는 장점 때문에 후보소재로 고려되고 있다. 하지만 카본블랙의 전도도는 전극으로 사용되기에 상대적으로 낮다. 이에 비해 그래핀은 뛰어난 전기전도도 및 유연성 때문에 촉망받고 있는 전자소재이다. 따라서 그래핀을 첨가한 카본블랙은 신축성 전극으로 적합한 소재로 예상된다. 본 논문을 통해 인장 시 그래핀을 첨가한 카본전극의 전기적 특성을 연구하였다. 기계적인 인장은 전극 내의 균열(crack)을 형성시켜 도전경로의 파괴를 일으켰다. 하지만 인장으로 정렬된 그래핀은 카본필러 간의 연결성을 강화하고 도전구조를 유지하였다. 무엇보다도 그래핀 첨가로 인하여 인장 시 카본전극의 전자구조가 변화하여 전자를 효과적으로 전도하게 하였다. 결론적으로 그래핀 첨가를 통해 카본블랙 복합체에 신축성 전극으로의 가능성을 부여하였다.

[가솔린엔진] 초음파 연료 공급장치가 가솔린 엔진의 연비 및 배기가스에 미치는 영향

윤면근(M.K. Yoon),방효민(H.M. Bang),김진구(J.G. Kim),이홍섭(H.S. Lee),류정인(J.I. Ryu) 한국자동차공학회 1999 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

This study investigated engine performance and exhaust gas by comparing ultrasonic energy added gasoline fuel used ultrasonic energy fuel feeding system with the conventional gasoline fuel<br/> This results are obtained as follow<br/> 1. In engine performance, it was found that specific fuel consumption, brake power, and brake thermal efficiency was improved more 3.5%, 4.73%, 3.63% respectively in case of ultrasonic energy added gasoline fuel than in case of conventional gasoline fuel.<br/> 2. We knew that ultrasonic energy decreases HC and CO, decreases NOx at low load but increases at high load

혈관조영제의 신독성에 관한 연구

이성만,박용원,이종국,오상준,이홍섭,김창호 인제대학교 1993 仁濟醫學 Vol.14 No.3

600mOsm/kg의 저삼투질 농도를 가진 ioxaglate(Hexabrix 320)의 신독성 여부를 관찰한 결과 탈수 상태에서 2.0 ml/kg 이상을 사용하게 되면 신세뇨관 손상이 야기되는 것을 관찰할 수 있다. This study was aimed at checking whether tri-iodinated compounds with greater solubility and low osmolality, Na or meglumine ioxaglate(Hexabrix 320, Guerbet Lab., France) has nephrotoxicity. Subjects were 21 children admitted to our hospital for the evaluation of their congenital heart diseases. None of them had any evidence of renal dysfunction before the study. They were deviled into 2 groups, one was low-dose group(Hexabrix given, < 2.0ml/kg) and the other one was high-dose group(≥ 2.0ml/kg). Renal function studios including serum creatinine(Scr), fractional excretion of sodium(FENa) and urinary β2-microglobulin excretion(UBME, mg of β2-microglobulin per gm creatinine) were done before and after Hexabrix administration. Statistical analyses were done using paired t-test and Wilcoxon signed rank test. Results were as follows ; 1.There were no significant differences of Scr and FENa between before-and after-Hexabrix study. 2.There were significant differences of UBME before - and after- Hexabrix study. 3.Comparing 2 groups, high-dose and low-dose group, with regard to UBME, there was significant increase of UBM in high-dose group after Hexabrix study but not in low-dose group. 4.Uric acid and/or calcium oxalate crystaluria appeared after Hexabrix administration. In conclusion, we confirmed that Hexabrix 320 could induce renal injury, particularly proximal tubular dysfunction, in recommended dosages for cardiac evaluations and that was dose dependent.

라디칼 억제 물질의 재관류 손상 예방에 관한 연구

이홍섭,김형묵 고려대학교 의과대학 1989 고려대 의대 잡지 Vol.26 No.3

Oxygen derived free redicals are thought to cause myocardial damage during reperfusion of ischemic myocardium. We have used the isolated working heart model and 60 minutes of hypothermic cardioplegic arrest to evaluate whether Allopurinol (xanthine oxidase inhibitor) or tocopherol (antioxidant) can improve postischemic myocardial recovery. Thirty rabbit hearts were divided into three groups (control, allopurinol and tocopherol group). Allopurinol(100㎎/㎏) or tocopherol (200IU/㎏) was administered orally 24 hour before experiment. Rabbits heart were subjected to one hour of global ischemia dunng which myocardial protection was provided by hypothermia (10℃) along with multidose St. Thomas cardioplegic solution cardioplegia. Both drugs significantly improved postischemic recovery of cardiac function, oxygen consumption and oxygen extraction. Leakage of creatine kinase was low in tocopherol and allopurinol groups. We conclude that pretreatment of allopurinol and tocopherol prevents myocardial injury in reperfused hypothermic ischemic heart.