산화물기반 박막트랜지스터 전극용 ITO박막의 제작시 투입 산소 분압 의존성

김경환,Kim, Kyung Hwan 한국반도체디스플레이기술학회 2021 반도체디스플레이기술학회지 Vol.20 No.2

In this study, we investigated the oxygen partial pressure effect of ITO films for electrodes of oxide-based Thin-Film Transistor (TFT). Firstly, we deposited single ITO films on the glass substrate at room temperature. ITO films were prepared at the various partial pressures of oxygen gas 0-7.4% (O₂/(Ar+O₂)). As increasing oxygen on the process of film deposition, electrical properties were improved and optical transmittance increased in the visible light range (300-800 nm). For the electrode of TFT, we fabricated a TFT device (W/L=1000/200 ㎛) with ITO films as the source and drain electrode on the silicon wafer. Except for the TFT device combined with ITO film prepared at the oxygen partial pressure ratio of 7.4%, We confirmed that TFT devices with ITO films via FTS system operated as a driving device at threshold voltage (V_th) of 4V.

심장판막 치환술을 병행한 관상동맥 질환의 수술

김경환,채헌,노준량,Kim, Kyung-Hwan,Chae, Hurn,Rho, Joon-Ryang 대한흉부심장혈관외과학회 1994 Journal of Chest Surgery (J Chest Surg) Vol.27 No.3

Between March, 1989, and August, 1993, 10 patients underwent aortocoronary bypass surgery concomittant with cardiac valve replacement. They were 6 men and 4 women, the age ranging from 47 to 64. 7 patients underwent single valve replacement and 2 patients underwent double valve replacement, Another one patient underwent only CABG one year after valve replacement and he had no evidence of prosthetic valve failure. Total number of graft vessels were.15,14 were saphenous venous grafts and 1 was internal mammary artery graft. Dyspnea on exertion was frequent symptom and was found in all patients. 8 patients presented stable angina, only 1 patient presented postinfarct angina and another 1 patient presented no angina symptom. The graft was placed prior to valve replacement and periods of myocardial ischemia were kept at a minimum by maintaining coronary perfusion throughout operation. Postoperative course was uneventful and there was no hospital mortality, as was supported by many reports, it is our opinion that simultaneous valve replacement and aortotomy bypass graft does not increase the risk of cardiac valve replacement substantially.

대동맥궁 절제술의 임상적 고찰

김경환,안혁,Kim, Kyung-Hwan,Ahn, Hyuk 대한흉부심장혈관외과학회 1994 Journal of Chest Surgery (J Chest Surg) Vol.27 No.11

From October 1990 to May 1993, 19 patients underwent replacement of the transverse aortic arch. [10 men, 9 women, mean age 52.5 years] Underlying diseases were acute aortic dissection [10 cases], chronic aortic dissection [4 cases],and aortic arch aneurysm [ 5 cases]. In 19 patients, 10 underwent partial replacement and 9 underwent total arch replacement. The cerebral protection was achieved by profound hypothermia [rectal temperature,16$^{\circ}$ to 2$0^{\circ}C$] associated with total circulatory arrest [mean 35.5 minutes]. In one patient, the aortic arch distal to the left common carotid artery was resected with the distal arch being cross-clamped and in another two patients, the selective cerebral perfusion was also applied during the period of total circulatory arrest via innominate artery and left common carotid artery because of longer total circulatory arrest time. Among 14 patients of aortic dissecton, 10 presented hypertension, 1 presented Marfan syndrome, 1 presented pregnancy-induced hypertension and 2 revealed no evidence of hypertension. All of the above 14 patients complained chest pain. Among 5 patients of aortic arch aneurysm, Be het disease was suspected in only one patient and atherosclerotic aneurysm was proved in another 4 patients. The overall hospital mortality was 32% [6/19]. In aortic dissection, the mortality was 43% [Acute aortic dissection 30%, chronic aortic dissection 75%] and in aortic arch aneurysm, the mortality was 0%. Follow-up was done in all survivors for from 7 months to 36 months[mean,17.3%].

대한민국 흉부외과 수술자료수집을 위한 코드

김경환,김광택,노환규,박승일,박영환,선경,성숙환,송현,심영목,원태희,임청,이정렬,정경영,전태국,박수정,Kim, Kyung-Hwan,Kim, Kwang-Taek,Rho, Hwan-Kyu,Park, Seung-Il,Park, Young-Hwan,Sun, Kyung,Sung, Sook-Hwan,Song, Hyun,Shim, Young-Mok,Won, Tae-He 대한흉부심장혈관외과학회 2001 Journal of Chest Surgery (J Chest Surg) Vol.34 No.1

심장내 이물질: 선행 원인이 불분명한 환자에서 발견된 우심실내 봉합침

김경환,장지민,안혁,Kim, Kyung-Hwan,Chang, Ji-Min,Ahn, Hyuk 대한흉부심장혈관외과학회 2000 Journal of Chest Surgery (J Chest Surg) Vol.33 No.8

A 34 year-old woman was hospitalized with anterior chest pain and indigestion. Chest radiograph and computed tomogram revealed a sewing needle in the cardiac cavity. She had no histories of surgical intervention, drug abuse, or acupuncture. We removed the needle from the right ventricle under cardiopulmonary bypass.

흉부 대동맥 질환에서 스텐트-그라프트의 임상적 적용

김경환,이철,장지민,정진욱,안혁,박재형,Kim, Kyung-Hwan,Lee, Cheul,Chang, Ji-Min,Chung, Jin-Wook,Ahn, Hyuk,Park, Jae-Hyung 대한흉부심장혈관외과학회 2001 Journal of Chest Surgery (J Chest Surg) Vol.34 No.9

배경: 하행 흉부대동맥류를 포함한 대동맥 질환을 가진 환자들에서 히생한 대동맥내 스텐트-그라프트 삽입술의 치료효과와 추적성적 및, 대상 환자들의 임상적 특징을 통해 치료방법으로서의 적응과 역할을 알아보았다. 대상 및 방법: 1995년 이후 모두 8명의 환자에서 진단방사선과와 협진으로 스텐트-그라프트 삽입술을 시행하였으며, 시술 전 진단으로는 외상성 대동맥 파열이 3례, 동맥경화증성 대동맥류 3례, 흉부가성대동맥류 파열 1례, 매독성 대동맥염에 의한 흉복무대동맥류가 1례였다. 시술은 혈관조영실에서 혈관조영을 하면서 시행하였고, 전신마취가 3례, 국소마취가 3례였고, 2례에서 경막외 마취하에 시술하였으며, 사용한 스텐트-그라프트는 0.35mm 굵기의 스테인레스 강철사를 지그재그 형태로 구부려 만든 스텐트를 서로 연결하고 인조혈과(Dacton)을 입힌 후 봉합한 것으로 제조회사에 의뢰하여 자체제작 하였다. 결과: 시술받은 환자의 전례에서 스텐트-그라프트 삽입시 기술적 어려움은 없었으며, 스텐트-그라프트 삽입후 4일에서 7일 사이에 시행했던 추적검사(4례)에서 스텐트-그라프트 주위부 누출이나 당초 목표했던 위이에서의 이탈은 없었다. 1례의 외사성 대동맥 파열이 었었던 환자가 시술 후 13일째 급성호흡곤란증후군 및 다장기부전으로 사망하였고, 매독성 대동맥염이 있었던 흉복부 대동맥류 환자가 시술 후 6일째 상행대동맥 및 대동맥궁에 대한 수술을 시행받고 술후 22일째 문합부위 파열로 사망하였다. 결론: 대동맥내 스텐트-그라프트를 이용한 흉복부 대동맥 질환의 치료는 수술에 따른 이환률 및 사망률을 고려할 때 특히 다장기부전으로 수술이 어려운 경우 또는 수술 후 합병증의 발생이 강력히 우려되는 경우에 안전하게 시행할 수 있는 치료의 한 방편으로서 의미를 가진다고 사료된다.행성 이하선염과 파라인플루엔자 바이러스는 외피가 있는 170-180nm 이었다.$\pm$0.10(100분), 0.46$\pm$0.11(120분), 0.52$\pm$0.15(심폐기 재가동 30분), 0.62$\pm$0.15(60분), 0.76$\pm$0.17(심폐기이탈 30분), 0.81$\pm$0.20(60분), 0.84$\pm$0.23(90분) and 0.94$\pm$0.33(120분)를 보였고 이는 역행성 뇌관류 전에 비해 유의하게 증가된 소견이었다(p<0.05). 뇌신피질, 기저핵, 해마에서 전자현미경 조직 소견을 관찰하였으며 마이토콘드리아의 부종을 관찰할 수 있었다. 결론 : 역행성 뇌관류 120분 후에 S100 베타 단백의 유의한 증가를 관찰할 수 있었으며 뇌조직 손상과의 관련성은 좀 더 연구되어야 할 부분으로 생각된다. 장기 생존 모델을 통한 재평가가 필요하다고 사료되며 심폐바이패스 시행 등의 교란 인자도 고려해야 할 것이다.비해 Progenitor II의 형질전환 효율이 현저히 떨어졌다. L. acidophilus HY7008과 HY7001은 두 기기 모두 형질전환이 이루어졌으나, L. acidophilus WEISBY와 NCFM은 Progeni-tor II에서 전이가 일어나지 않았으며, Gene Pulser에서 전이균주를 얻어 두 electroporator간에 형질전환 효율의 차이를 보였다. 11. L. casei 102S에 pLZ12를 electroporation시 낮은 전압에서 형질전환 효율이 비교적 좋았으며, 배양 시기를 달리하여 전이시켰을 때 대수생장 말기의 세포가 형질전환 효율이 좋았다. 12. Background: Endovascular stent-graft insertion in aortic diseases is now generally accepted as an attractive alternative treatment modality. We reviewed our clinical experiences of endovascular stent-graft insertion in thoracic aorta. Material and Method: Since 1995, we performed 8 cases of endovasclar stent-graft insertion. Preoperative diagnoses were aortic aneurysms in 4, traumatic aortic ruptures in 3, and ruptured aortic pseudoaneurysm in 1. All procedures were performed in angiography room with the guidance of fluoroscopy. The stent-graft device is a custom-made 0.35mm thickness Z-shaped stainless steel wires, intertwined with each other using polypropylene suture ligation. It is covered with expanded Dacron vascular graft. Result: All procedures were performed successfully. Follow-up studies revealed 2 minimal perigraft leakages. There was no significant leakage or graft migration. 2 patients expired due to multiple organ failure and fungal sepsis. Other survivors(6) are doing well. Conclusion: Endovascular stent-graft insertion is relatively saft and effective treatment modality in the managment of various types of aortic diseases. In may be an effective alternative in aortic diseases of great surgical risk.

승모판 질환에 동반된 심방세동에 대한 폐정맥 분리술의 중기성적

김경환,김태헌,안혁,Kim, Kyung-Hwan,Kim, Tae-Hun,Ahn, Hyuk 대한흉부심장혈관외과학회 2001 Journal of Chest Surgery (J Chest Surg) Vol.34 No.4

배경: 항부정맥 술식으로서의 메이스 술식은 우수한 동율동 전환율을 보고 있으나, 술식의 복잡성과 상대적으로 긴 수술 시간 등으로 모든 환자들에게 적용할 수는 없기에, 일부 환자군에서 보다 간단한 항부정맥술인 폐정맥 분리술을 시행 받은 환자들을 대상으로 동율동 전환율 등의 수술 성적과 위험 인자 등에 대해 알아보고자한다. 대상 및 방법: 1995년 10월부터 1999년 2월까지, 폐정맥 분리술을 시행받은 96명의 환자들을 대상으로 후향적 연구를 시행하였다. 남자가 37명(38.5%), 여자가 59명(61.5%) 이었고, 평균 연령은 46.9$\pm$11.6세 이었다. 승모판 협착 환자가 50명(52.1%), 폐쇄 부전이 24명(25%), 협착과 폐쇄부전이 같이 있었던 경우가 22명(22.9%)이었다. 판막 술식과 폐정맥 분리술을 시행하고 좌심방이 제거술을 시행하였다. 모든 환자들은 술 후 6개월 내지 1년 이내에 외래에서 심전도와 심초음파를 시행받았다. 평균 추적 관찰 기간은 25.9$\pm$11.5개월 이었다. 술 후 최근 추적일까지 동율동으로 전환된 군과 안된 군으로 나누어 분석을 하였다. 결과: 조기 성적으로는 사망이 3명(3.1%), 술 후 6개월 이내의 추적관찰 유실이 2명(2.1%) 이었다. 조기 합병증으로 재수술이 필요 했던 출혈이 4례, 심폐바이패스 이탈 실패오 심실보조장치 등의 삽입이필요했던 경우가 1례, 뇌혈관질환 1례, 심근경색이 1례 등이 있었다. 만기 합병증으로는 동기능 부전 증후군으로 영구 심박동기를 삽입한 경우가 1례, 일시적인 뇌경색 1례 있었고 다른 판막과 연관된 합병증은 없었다. 동율동 전환 환자 수는 75명(82%)이었다. 동율동으로의 전환이 어려운 위험인자로 50세로 이상의 연령(p=0.03), 65mm 이상의 좌심방 크기(p=0.03), 동반 우심 술식 시행(p=0.02)등이 있었다 결론: 승모판 질환을 동반한 심방 세동 환자에서 폐정맥 분리술을 시행하여 만족할 만한 동율동 전환율을 얻을 수 있었다.

일개 병원에서의 일산화탄소 중독증으로 내원한 환자에 대한 분석

김경환,김아진,신동운,노준영,Kim Kyung Hwan,Kim Ah Jin,Shin Dong Wun,Rho Jun Young 대한임상독성학회 2005 대한임상독성학회지 Vol.3 No.1

Purpose: The frequency of carbon monoxide poisoning has been decreased in the interior of the Korea. But occasionally it is occurred and the risk of exposure is high in working place so far. Because of the characteristics of gas, the detection of exposure and poisoning could be delayed and fatality is high. We should apprehend of carbon monoxide poisoning. So we would report analysis of patients with carbon monoxide poisoning. Methods: A retrospective review of CO poisoned patients visited emergency department from January 2000 to December 2004 was conducted. Results: 24 patients were enrolled. Their average of age was $37.6\pm20.9$ years old and COHb was $19.4\pm13.32\%$. The blood level of initial COHb and mental status on arrival were not correlated each other. The blood level of initial COHb and loss of consciousness were not correlated, too. Initial electrocardiography (EKG) was not correlated with cardiac enzymes such as CK-MB and troponin I. But base excess was correlated with mental status on arrival and complication such as rhabdomyolysis. Hyperbaric oxygen therapy was correlated with base excess and mental status on arrival. Conclusion: The clinical features of carbon monoxide poisoning are nonspecific. For proper diagnosis, it is important that we should consider patient's environment and take patient's history carefully. The blood level of initial COHb does not reflect severity of poisoning accurately. So We should determine the treatment of choice depending on patient's status.

안드로이드 플랫폼 상에서 동기화가 고려된 통합 커서의 설계 및 구현

김경환,하주호,원종필,이의성,김주민,손진호,Kim, Kyung-Hwan,Ha, Jo-Ho,Won, Jong-Pil,Lee, Uee-Song,Kim, Joo-Min,Son, Jin-Ho 대한임베디드공학회 2011 대한임베디드공학회논문지 Vol.6 No.3

Android platform provides a content provider and a cursor mechanism to access the internal SQLite engine. Content providers not only store and retrieve data but also make it accessible to applications. Applications can only share data through content provider, since there's no common storage area that Android packages can access. Cursor is an interface that provides random read-write access to the result set returned by a database query. However, this cursor possesses two major limitations. First, a cursor does not support a join clause among cursors, since the cursor can only access a single table in the content provider. Second, the cursor is not capable of creating user-customized field in the predefined content providers. In this paper, we propose the unified cursor architecture that merges several cursors into a single virtual cursor. Cursor translation look-aside buffer (TLB), column windowing mechanism and virtual data management are the three major techniques we have adopted to implement our structure. And we also propose a delayed synchronization method between an application and a proposed unified cursor. An application can create a user-customized field and sort multiple tables using a unified cursor on Android platform.

펀측 상지에 적용된 고유수용성 신경근 촉진법이 반대측 하지의 근 활성도에 미치는 영향

김경환,박지원,배성수,Kim, Kyung-Hwan,Park, Ji-Won,Bae, Sung-Soo 대한고유수용성신경근촉진법학회 2006 PNF and Movement Vol.4 No.1

Purpose: The purpose of this study was to investigate the effect of Proprioceptive Neuromuscular Facilitation (PNF) applied to the unilateral upper extremity on the muscle activation of contralateral lower extremity. Twenty-two healthy subjects (mean age of 23.7 years) participated in this study. Method : PNF patterns applied on the unilateral upper extremity in all subjects were the flexion/abduction/external rotation and lifting pattern. The hold and appoximation techniques for the irradiation were applied to end range of both patterns. Muscle activations in four patterns were measured in vastus medialis, tibialis anterior, rectus femoris, and gastrocnemius medial muscles of contralateral lower extremity using surface EMG system. Each EMG value in individual muscle was normalized for maximal voluntary contraction. The data were analyzed by one factor analysis of variance with repeated measure test. Result : There were significant differences in the between-subject effect (muscles) and within-subject effect (patterns) in comparison of muscle activation by application of PNF patterns (p<.05). The irradiation led to higher activation in the flexion/abduction/external rotation pattern than that of lifting pattern in all muscles (p<.05). The approximation techniques revealed more activations than these of hold technique in all muscles (p<.05). Conclusion : These results suggest that the application of PNF patterns to the unilateral upper extremity affect on the muscle activation of contralateral lower extremity and increase according to the intensity of resistance. This mechanism of contralateral effect might provide a help to the development of treatment method for the affected side and functional improvement for the patients who have damages of central nervous system or musculoskeletal problems by orthopedic injury.