구리를 함유하지 않은 친환경 자동차 브레이크 패드의 마모 특성에 관한 연구

김기봉,양상선,이성주,황석훈,김신욱,김용진,Kim, Ki-Bong,Yang, Sangsun,Lee, Seong-Ju,Hwang, Suk-Hun,Kim, Sin-Wook,Kim, Yong-Jin 한국분말야금학회 2018 한국분말재료학회지 (KPMI) Vol.25 No.1

The friction characteristics of Al-Fe alloy powders are investigated in order to develop an eco-friendly friction material to replace Cu fiber, a constituent of brake-pad friction materials. Irregularly shaped Al-Fe alloy powders, prepared by gas atomization, are more uniformly dispersed than conventional Cu fiber on the brake pad matrix. The wear rate of the friction material using Al-8Fe alloy powder is lower than that of the Cu fiber material. The change in friction coefficient according to the friction lap times is 7.2% for the Cu fiber, but within 3.8% for the Al-Fe alloy material, which also shows excellent judder characteristics. The Al-Fe alloy powders are uniformly distributed in the brake pad matrix and oxide films of Al and Fe are homogeneously formed at the friction interface between the disc and pad, thus exhibiting excellent friction and lubrication characteristics. The brake pad containing Al-Fe powders avoids contamination by Cu dust, which is generated during braking, by replacing the Cu fiber while maintaining the friction and lubrication performance.

성별에 따른 청소년의 스마트폰 사용의 문제적 경험 관련 요인

김기봉,문원희,권명진,Kim, Ki-Bong,Moon, Weon-Hee,Kwon, Myoung-Jin 중소기업융합학회 2021 융합정보논문지 Vol.11 No.10

This study was conducted to identify factors related to the problematic experiences of smartphone use among adolescents according to gender. The subjects of this study were 54,603 male and female adolescents. This study data was analyzed using SPSS 25.0 program. As a result of this study, the relevant factors for the problematic experiences of smartphone use among male students were academic performance, economic level, counselors, fast food consumption frequency, depression, suicidal ideation, suicide plan, happiness, subjective body image, stress, and smartphone usage time. Drinking and smoking were found to be significant related factors only for female students. Therefore, in order to reduce the problematic experience of smartphone use, an intervention considering the influence factors according to gender is required. 본 연구는 성별에 따른 청소년의 스마트폰 사용의 문제적 경험과 관련된 요인을 파악하고자 시행되었다. 본 연구 대상자는 제13차(2017년) 청소년건강행태온라인조사에서 스마트폰 사용 문제적 경험 문항에 답한 남녀 청소년 54,603명이었다. 본 연구 자료는 SPSS 25.0 program를 이용하여 분석하였다. 본 연구 결과 남학생의 스마트폰 사용의 문제적 경험의 관련 요인은 학업성적, 경제수준, 고민을 상담해 주는 사람, 패스트푸드 섭취빈도, 우울, 자살사고, 자살계획, 행복, 주관적 신체상, 스트레스, 스마트폰 사용 시간이었다. 음주와 흡연은 여학생에게만 유의한 관련 요인으로 나타났고, 자살계획은 남학생에게서만 유의하게 나타났다. 그러므로 스마트폰 사용의 문제적 경험을 감소시키기 위해서는 성별에 따른 영향요인을 고려한 중재가 요구된다.

마황, 인삼, 택사 복합추출물의 endocannabinoid system 억제를 통한 비알콜성 지방간 유도 인슐린저항성 개선 효과

김기봉,안상현,Kim, Ki Bong,Ahn, Sang Hyun 대한한방소아과학회 2020 대한한방소아과학회지 Vol.34 No.4

Objectives This study aimed to investigate the efficacy of Ephedra sinica (E. sinica), Panax ginseng (P. ginseng), and Alisma orientale (A. orientale) Extract (MIT) on insulin resistance induced by Non-alcoholic fatty liver disease (NAFLD). Methods C57BL /6 male mice (8-week-old, 20 g) were divided into four groups: control group (Ctrl), high-fat diet group (HFDF), high fat diet with metformin administration group (METT), and high fat diet with MIT administration group (MITT). Each 10 mice were allocated to each group (a total of 40 mice). All mice were allowed to eat fat-rich diet freely throughout the experiment. To examine the effect of MIT, we observed Cannabinoid receptor type 1 (CB1), Cannabinoid receptor type 2 (CB2), G protein-coupled receptor 55 (GPR55), and Transforming growth factor-β (TGF-β). Results In the MITT group, positive reactions of the CB1, CB2, and GPR55 were significantly was significantly suppressed compared to the HFDF group. The positive reactions of the CD36 and TGF-β in the liver tissue were significantly suppressed in MITT. Conclusions MIT has the effect of improving NAFLD induced insulin resistance through the regulation of the lipid metabolism.

심장세동의 수술요법

김기봉,이창하,손대원,Kim, Gi-Bong,Lee, Chang-Ha,Son, Dae-Won 대한흉부심장혈관외과학회 1997 Journal of Chest Surgery (J Chest Surg) Vol.30 No.3

심방세동은 가장 흔한 부정맥 질환으로서,특히 승모판막 질환이 있는 경우에는 60%에 이르는높은 빈도의 유병율을 보이는데,심방세동 환자의 약 113에서 혈전 색전증을 일으키고,혈전 색전증이 생긴 환자의 약 60%에서는 사망에 이르거나 심각한 합병증이 초래되므로 심장질환에 대한 수술시,동반 심 방세동에 대한 적극적 인 치료가 고려되어야 한다. 서울대학교병원 흉부외과학교실에서는 1994년 4월부터 1995년 6월까지 심방세동을 동반한 심장질환 을 가진 20명의 환자에서 Maze 술식을 포함한 개심술을 시행하였다 대상환자들의 남녀 성비는 남 '녀 : 6 : 14 이 었으며, 평균연령은 48$\pm$11세 (31 ~66세) 였다. 1년이상 지 속된 만성 심방세동이 14례(70%)였고, 1년미만인 경우가 6례(30%)였으며,심방세동의 과거력은 평균 36$\pm$42개월(1~132개월)이었다. 수술전 혈전전색증의 과거력이 있었던 경우가 7례(35%), 좌심방내에 혈전이 있었던 경우가 9례(45%)였다. 동반 심장질환으로는 판막질환이 19례,심실중격결손증이 1례였 으며, Maze술식과 더불어 승모판막 및 대동맥판막 치환술이 5례, 승모판막 치환술을 시행한 경우가 4 fl, 승모판막 치환술 및 삼첨판\ulcorner 성형술 4례, 승모판막 성형술 3례, 승모판막 성형술 및 삼첨판막 성형 술이 1례, 승모판막 치환술 및 관상동맥 우회술이 1례, 대동맥판막 치환술 1례, 심실중격결손봉합술이 1례 였다. 대동맥차단시간은 평균 175 :41분(116~270분)이었다. 수술과 관련된 사망은 없었으며, 수술 후 심방세동의 재발이 16명(80%)에서 있었으나, 수술후 평균 41일째 규칙적인 심박동 소견을 보였다. 수술후 합병증으로서는 저심박출증을 보였던 경우가 3례 (15%), 술전 존재하였던 반신불수의 악화가 1 례, 그리고 급성 신부전이 1례씩 관찰되었다. 20명의 외래추적 관찰기간은 평균 16.5개월(10.5~24개월) 이었는데, 외래 추적기간 중 모든 환자에서 규칙적인 심박동의 소견을 보였으며, 정상 동방결절리듬을 보인 경우 17례 (85%)중에서 항부정맥제의 투여가 필요 없는 경우가 13례 (76%)이고 나머지 4례에서는 항부정맥제를 투여중이며, 접합부 율동을 보이는 3례 (15%) 중 2례에서는 항부정맥제를 투.i중이고, 1 례는 접합부 서맥으로 인공심박동기 (DDD-R type : AAI mode)의 삽입이 필요했다. 추적기간 중에 심에 코검사는 19명에서 시행하였는데, 우심방 수축력이 보이는 경우가 1 례 (95%) 이었고, 좌심방 수축력은 12례 (63%)에서 명백히 관찰되 었다. 심장질환에 대한 개심술시 Maze술식을 동반시행할 경우심장허혈시간이 길어지는 단점이 있으나, 최근의 발달된 심근보호법의 적용으로 수술에 따른 위험을 최소화할 수 있으므로 심방세동의 적극적 인 치료를 고려하여야 할 것으로 사료된다. .Itrial fibrillation is one of the most common cardiac arrhythmias requiring treatment. About 60% of patients with mitral valvular disease have atrial fibrillation and one third of patients with atrial fibrillation may have the past history of thromboembolic events. Between April 1994 and June 1995, 20 patients with organic heart diseases combined with atrial fibrillation underwent open heart surgery including Cox-maze 111 procedure. There were 6 men and 14 women with an average age of 48 years (range, 31 to 66 years). Nineteen patients had valvular heart diseases and 1 ventricular septal defEct (VSD). Mean duration of atrial fibrillation was 36 months (:42 months) (range, 1 to 132 months). T e past medical history of thromboembolic events was positive in 7 patients (35%) and left atrial thrombus was detected in 9 patients (45%). The concomitant procedures were mitral valve replacement (MVR) and aortic valve replacement (AVR) in 5 patients, MVR in 4, MVd and tricuspid annuloplasty(TAP) in 4, mitral valvuloplasty(Mln) in 3, Mln and Tln in 1, MIW and coronary artery bypass surgery in 1, AVR in 1, and patch closure of VSD in 1. Mean aortic cross-clamping time was 175 minutes (range, 116 to 270 minutes). Atrial fibrillation recurred in 16 patients (80%) during the early postoperative period, but, recurrent atrial fibrillation was converted to regular rhythm at postoperative forty-first day in average. There was no early or late death in this series of 20 patients and postoperative complications were inappropriate tachycardia in 5 patients (25%), low cardiac output syndrome in 3 (15%), aggravated hemiplegic in 1, and acute renal failure in 1. Mean follow-up interval of patient was 16.5 months (range, 10.5 to 24 months) and all patients are currently in regular rhythm. Seventeen patients (85%) are in sinus rhythm and 3 (15%) in junctional rhythm. Right atrial contraction was detected in 95% of patients and left atrial contraction in 63% on postoperative transthoracic echocardiogram. The surgical treatment of atrial fibrillation concomitant with open heart surgery is warranted in the recent clinical setting of improved myocardial protection technique, considering the untoward side-effects of atrial fibrillation.

소아(小兒) 기억(記憶)에 관한 한의학적(韓醫學的) 고찰(考察)

김기봉,김장현,Kim Ki-Bong,Kim Jang-Hyun 대한한방소아과학회 2000 대한한방소아과학회지 Vol.14 No.1

In children, the poor intelligence and failing of study from it raise problems in mentality, character and society. The poor intelligence and failing of study are closely connected with brain, Xin(心), Shen(神), Jing(精), Qi(氣). In this paper, studying causes of the poor intelligence and failing of study, through documents, I can obstain such conclusions. 1. Xin(心) takes charge of brain and manages life, mind and mentality. 2. Shen(神) controls mind and Jing(精) is the origin of life. So Shen and Jing must be built up for increase of memory and study. 3. For increase of intelligence and study, Qi(氣) must go round smoothly. 4. Causes of the poor intelligence and failing of study are the lack of blood, damage of Shen(腎), huo(火), phlegm etc.

총폐정맥 이상환류증의 수술요

김기봉,노준량,Kim, Gi-Bong,No, Jun-Ryang 대한흉부심장혈관외과학회 1984 Journal of Chest Surgery (J Chest Surg) Vol.17 No.1

Total anomalous pulmonary venous connection [TAPVC] defines a group of congenital heart disease which have in common the entire pulmonary venous drainage returning directly or indirectly to the right atrium instead of to the left atrium. Although this disorder represents only 1.3% of cases of congenital heart disease, if untreated the resultant mortality is greater than 80% in the 1st year of life. And since there is no satisfactory palliative treatment, correction of TAPVC Is high on the list of indications for open heart surgery in the 1st year of life. This paper describes 10 patients who underwent surgical correction of this disorder at SNUH between 1978 and 1983. 1. 7 were males and 3 females, with ages ranging from 5 months to 24 years. 2. 7 were supracardiac type, 2 cardiac type, and 1 mixed type TAPVC. We didnt experience infracardiac type. 3. All showed some degree of pulmonary hypertension preoperatively. 4. In 4 cases of supracardiac type, total circulatory arrest was used in brief period during anastomosis between common pulmonary venous trunk and left atrium. In the other cases, usual cardiopulmonary bypass with moderate to deep hyperthermia was used. 5. There were 2 cases of mortality; 1 died at operation, and the other at 4 months due to congestive heart failure. 6. Mortality seemed not closely related to age, body weight, or severity of pulmonary hypertension.

교정형 대혈관전위증동반된 심혈관기형의 수술요

김기봉,노준량,서경필,Kim, Gi-Bong,No, Jun-Ryang,Seo, Gyeong-Pil 대한흉부심장혈관외과학회 1984 Journal of Chest Surgery (J Chest Surg) Vol.17 No.3

Corrected transposition of the great arteries [C-TGA] is one of the rare congenital heart disease in which there is both a discordant atrioventricular relationship and transposition of the great vessels. With this arrangement, systemic venous blood passes through the right atrium into the morphologic left ventricle and out the pulmonary artery. Pulmonary venous blood returns to the left atrium, flows into the morphologic right ventricle and out the aorta. Thus, in the rare case when no additional cardiac anomaly is present, a hemodynamically normal heart exists. But more often they are symptomatic as a result of one or several of the commonly associated defects. This paper describes 13 patients who underwent repair of one or more cardiac anomalies associated with corrected transposition at SN UH, from June 1976 through June 1984. 1.8 were males and 5 females, with ages ranging from 3 years to 27 years. 2. Segmental anatomy was {S,L,L} in 12, or {I,D,D} in 1. 3.Associated anomalies were ventricular septal defect in 10, pulmonary outflow tract obstruction in 6, tricuspid insufficiency in. 4, atrial septal defect in 3, subaortic stenosis in 1, mitral insufficiency in 1, and patent ductus arteriosus in 1. 4.None had complete heart block preoperatively, and 3 developed complete heart block intraoperatively. But one of them recovered sinus rhythm on the postoperative 7th day spontaneously. 5.There were 3 cases of hospital morality. But there was no morality since Dec. 1980. 6.Patients with single ventricle, hypoplastic ventricle or those who had palliative surgery alone are not included in this review.

프로모터 영역의 전사인자 결합부위 Consensus 패턴 탐색 방법

김기봉,Kim, Gi-Bong 한국유전체학회 2007 유전체소식 Vol.7 No.4

전소엽의 열구에 의한 승모판막부전치험 1례

김기봉,조대윤,서경필,Kim, Gi-Bong,Jo, Dae-Yun,Seo, Gyeong-Pil 대한흉부심장혈관외과학회 1985 Journal of Chest Surgery (J Chest Surg) Vol.18 No.1

A cleft in the anterior mitral valve leaflet is commonly associated with atrioventricular septal defects, but may occur as an isolated phenomenon. The cleft mitral valve can cause regurgitation, and surgical treatment of the cleft leaflet should conserve the existing valve if possible. But if satisfactory hemodynamic security cannot be obtained with a reconstructive procedure, the valve should be replaced. We present one case of an isolated cleft in the anterior mitral valve leaflet. The patient showed marked mitral regurgitation in the preoperative left ventriculogram. We managed him successfully by interrupted suture repair of the cleft, and he was discharged uneventfully.

고폐동맥압을 동반한 선천성 심기형 환자에서 술후 폐동맥압과 혼합정맥혈 산소분압의 변화에 관한 분석

김기봉,김용진,Kim, Gi-Bong,Kim, Yong-Jin 대한흉부심장혈관외과학회 1989 The Korean Journal of Thoracic and Cardiovascular Vol.22 No.6

It has been suggested that mixed venous $O_{2}$ tension is a predicor of cardiac output especially in a critically ill patient after an open heart surgery. From April 1988 through September 1989, we monitored mixed venous $O_{2}$ tension and pulmonary arterial pressure in 48 patients with acyanotic congenital heart disease at postoperative 1 hour, 6 hour, 12 hour, 24 hour, and 48 hour respectively. They were divided into Group I, with severe pulmoary hypertension, and Group II, without severe pulmonary hypertension. In Group I, mixed venous $O_{2}$ tension and cardiac index showed significant increase with time (p<0.05), but the ratio of pulmonary-aortic systolic pressure didn't show significant change. The increase was significant only 24 hour after operation, and so this low cardiac performance in early postoperative period should be considered when postoperative management is being planned in the risky patient. In Group II, all of the three variables didn't show any significant change with time. The correlation coefficient between mixed venous $O_{2}$ tension and cardiac index was significantly different from zero in both Group I (p<0.001) and group II (p<0.05) at each imeperiod, but the ratio of pulmonary-aortic systolic pressure didn't correlated well with the other 2 variables. Our study showed that serial determination of mixed venous $O_{2}$ tension in acyanotic congenital heart disease could be used as a guide in estimating the cardiac index postoperatively.