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.

소아(小兒) stress에 관한 문헌적(文獻的) 고찰(考察)

김기봉,김장현,Kim, Ki-Bong,Kim, Jang-Hyun 대한한방소아과학회 2002 대한한방소아과학회지 Vol.16 No.1

With the progress of civilization, the disorders due to the stress, which derived from the social-structural complexity and diversity, are on an increasing trend in our times. Accordingly, the accurate diagnosis and appropriate treatment for them are required. Especially in the current years, children's disorders delivered by the emotional problems keep increasing. In this research, the researcher tried to figure out the cause of the children's stress and its treatment, studied the theories of the stress in the modem medicine and the sever emotions in oriental medicine, and came to the conclusion as follows: 1. The stress can be defined as the combination of the reaction to noxious stimuli and its defense mechanism of the body, In oriental medicine, it is considered as pathological notions which includes seven emotions as the internal factor, six evils as the external factor and other foods, expectoration, ecchymoma as the non-internal/external factors. 2. Children usually get stressed by various reasons in a growth process such as schooling, relationship with friends, the opposite sex of family, or change of surroundings, and these can cause the various disorders. 3. In the study of the children's stress symptoms, it is found that the silent reaction is uncommon. It usually appeared in both reactions: firs, physical reactions such as stomachache, vomiting, headache, neural frequent urination, bronchial asthma or excessive respiration and/or, second, behavioral reactions such as a decline of performance, alimentary disorder, e.g. anorexia nervosa or bulimia, sleep disorder, e.g. nightmare or panic in sleep, anthrophobia, refusal to a school attendance or hyperactiveness. Besides, the peculiar mental disorder such as paroxysm of anger, tic, autism, nocturnal enuresis, lack of attentiveness, impediment in linguistic development, learning difficulty, intellectual decline, etc. can be appeared, and the heavy stress during the babyhood can cause the regression of behavior or the immaturity of formation of character. 4. The appropriate treatments for the children's stress are Osteopathy, Manpulation, Aroma Therapy, Alexander Technique, Autonomic Never Control Treatment, Biofeedback, Chiropractic, Dance Therapy, Feldenkrasis Technique, Gravity Therapy, Homepathy, Aquatherapy, Hypnotherapy, Naturopathy and Meditation.

선천성 Valsalva 동 동맥류의 수술요법

김기봉,서경필,Kim, Gi-Bong,Seo, Gyeong-Pil 대한흉부심장혈관외과학회 1985 Journal of Chest Surgery (J Chest Surg) Vol.18 No.2

Congenital aneurysm of sinus of Valsalva is one of the rare congenital heart disease, which is usually asymptomatic until rupture. The aneurysm usually ruptures into a cardiac chamber and produces an aorto-intracardiac fistula. Ruptured aneurysm is a grave lesion in that it causes heart failure and subsequent death. If, however, it is discovered in its early stages and operated on properly, it can be corrected with considerable success. Form January 1975 through December 1984, 18 consecutive patients with congenital aneurysm of sinus of Valsalva underwent corrective surgery using total cardiopulmonary bypass in our department of Thoracic Surgery. 1. The incidence was about 0.9% of surgical cases of congenital heart disease during that period. 2. 13 were males and 5 females, with ages ranging 12 years to 52 years. 3. Associated anomalies were VSD in 14, infundibular PS in 1, aberrant muscle band in RVOT in 1, and secondary aortic insufficiency in 9. 4. 17 were suggested to arise from right coronary sinus and 1 from noncoronary sinus; Among 17, 12 ruptured into right ventricle, and one from noncoronary sinus into right atrium. 5. Surgical correction was performed by means of direct suture closure with combined pledget or patch graft after aneurysm resection, and associated lesions were also corrected simultaneously. 6. There was only one case of operative mortality, and all the other patients were relatively uneventful in their follow-up studies.

Senning씨 술식에 의해 교정한 완전 대혈관전위증에서의 심전도 변화에 관한 연구

김기봉,노준량,Kim, Gi-Bong,No, Jun-Ryang 대한흉부심장혈관외과학회 1985 Journal of Chest Surgery (J Chest Surg) Vol.18 No.4

One of the most widely recognized problems in patients with TGA [transposition of the great arteries] after the Senning operation is the occurrence of arrhythmias. From June 1982 through October 1984, 22 patients, 11 with "simple" and 11 with "complex" TGA, underwent correction of TGA by a modification of the Senning operation designed to avoid dysrhythmias. 16 were males and 6 females, with ages ranging from 3 months to 27 months. [mean age 10.8 months] 7 patients [31.8%], 1 with simple TCA and 6 with complex TGA, died in the early post-operative period. The operative mortality was 9.1% in "simple" TGA, and 54.9% in "complex" TGA. There were 4 late deaths but only one of these patients died of a dysrhythmia as a possible factor. The standard ECG [Electrocardiography] checked preoperatively showed sinus rhythm in 17 [77.3%], 1 AV block in 5 [22.7%]. In 22 patients studied postoperative 1st day, the incidence of arrhythmias was 63.6%, with significant incidence compared with preoperative study. [P<0.05]. But, in 15 patients studied postoperatively at intervals from 1 month to 26 months, the incidence of arrhythmias was 26.7%, with no significant incidence compared with preoperative study [P>0.1]. Our results indicate that a modified Senning operation may reduce the frequency of surgically induced arrhythmias. The mean frontal plane P-wave axis also revealed significant deviation to the right side [P<0.05], compared with preoperative study. These findings raise the possibility that what has been called sinus rhythm postoperatively may have a different origin and conduction sequence from normal. But the rhythm seems to be functionally similar.rhythm seems to be functionally similar.

Cox-Maze III 술식의 변형

김기봉,허재학,장지민,이정상,안혁,손대원,Kim, Ki-Bong,Huh, Jae-Hak,Chang, Ji-Min,Lee, Jeong-Sang,Ahn, Hyuk,Sohn, Dae-Won 대한흉부심장혈관외과학회 2000 Journal of Chest Surgery (J Chest Surg) Vol.33 No.11

배경: Cox-Maze III (CM-III) 술식은 복잡한 심방 절개로 인한 긴 수술시간 때문에 다른 개심 수술과 병행하여 시행하기 어려운 단점이 있다. 대상 및 방법: 저자들은 CM-III 술직을 다음과 같이 변형하여 시행하고 그 임상성적을 분석하였다. \circled1 좌심방이를 절제하는 대신 좌심방이를 외부에서 결찰하고, \circled2 폐정맥 분리 절개선과 좌심방이 사이에 냉동절제술을 시행하며, \circled3 우심방이를 절제하는 대신에 우심방 외측 절개선을 우심방이까지 연장하고, \circled4 후종 우심방 절개 하부에서 우심방 외측을 지나 삼첨판막륜으로 향하는 T-자 절개선을 생략하였다. 저자들이 시행한 변형 술식의 용이성과 효율성을 평가하기 위하여, 우리나라에서도 빈도가 높은 류마치스성 승모판막 질환에서, 전통적인 Cox-III 술식(그룹 I)의 임상결과와, 변형된 CM-III 술식(그룹 II)의 임상결과를 비교하였다. 결과: 그룹 I(n=18)에서 동반된 수술은 승모판막 치환술 10례, 승모판막 성형술3례, 승모판막 치환술과 삼첨판막륜 성형술3례, 승모판막 재치환술 2례 등이었다. 그룹II(n=23)에서 동반된 수술은 승모판막 치환술 7례, 승모판막 성형술 5례, 승모판막 치환술과 삼첨판막륜 성형술 1례, 승모판막 재치환술 10례 등이었다. 그룹 I과 그룹 II에서 평균 대동맥 차단 시간(ACC)은 각각 135$\pm$29분과 104$\pm$18 분, 심패바이패스(CPB) 시간은 각각 240$\pm$33분과 185$\pm$42분이었다. 그룹 I과 그룹 II의 평균 추적 관찰 기간은 각각 47$\pm$14 개월과 29$\pm$4 개월이었다. 그룹 I에서는 16례(88.9%)에서 정상 동율동으로 회복되었고 1례에서 심방세동이 남아 있었으며, 다른 1례는 서맥증후군(sick sinus syndrome)으로 인공 심박조율기를 삽입하였다. 그룹 II에서는 21례(91.3%)에서 정상 동율동으로 회복되었고 2례는 심방세동이 지속되었다. 그룹 I에서 정상동율동으로 회복된 16례는 100%(16/16)에서 우심방의 수축을 심장 초음파검사에서 확인할 수 있었으며, 좌심방의 수축은 75%(12/16)에서 확인할 수 있었다. 그룹 II에서는 정상 동율동으로 회복된 21례 중 100%(21/21)에서 우심방의 수축을 확인할 수 있었으며, 좌심방의 수축은 76.2%(16/21)에서 확인할 수 있었다. 결론: 변형 CM-III 술식은 전통 CM-III 술식에 비하여 ACC time(p<0.005)과 CPB time(p<0.001)을 의미있게 줄이면서도 필적할 만 한 정상 동율동 전환율과 심방 수축력의 회복을 보여주었다.

Valsalva형 동뇌류파열의 외과적 치료

김기봉,이영균,Kim, Gi-Bong,Lee, Yeong-Gyun 대한흉부심장혈관외과학회 1986 Journal of Chest Surgery (J Chest Surg) Vol.19 No.1

Over the past 11 years, from Jan. 1975 through Nov. 1985, 27 consecutive patients with congenital aneurysms of sinus of Valsalva underwent corrective surgery in our department of Thoracic Surgery. 26 were suggested to arise from right coronary sinus and 1 from noncoronary sinus: among 26, 18 ruptured into right ventricle, 1 into right atrium, 1 into pulmonary artery. And 1 from noncoronary sinus into right atrium. Among 18 cases of preoperatively diagnosed as ruptured aneurysm, the fistula was repaired through the aorta in 12, although the chamber of termination was also opened in some. Recurrent fistula occurred in 2 cases in which the ruptured aneurysm was repaired through right ventricle. It appears that repair of the fistula itself is best carried out through an aortotomy, after cross-clamping.

심막 낭종의 외과적 수술3례 보고

김기봉,김주현,Kim, Gi-Bong,Kim, Ju-Hyeon 대한흉부심장혈관외과학회 1983 Journal of Chest Surgery (J Chest Surg) Vol.16 No.1

Pericardial cysts are infrequent benign intrathoracic lesions. They rarely cause symptoms, and they are usually discovered on routine X-ray by chance. Over 70% of the cases occur at the right anterior cardiophrenic angle. Surgery is generally not indicated if the diagnosis of pericardial cyst can be made with certainty, and then an operation is performed to rule out other lesions. The authors present 3 cases of pericardial cyst confirmed by surgery. In two Gases Of the three, the pericardial cysts were located at the right anterior cardiophrenic angle, and in one case, at the left superior area of the posterior mediastinum. We managed them successfully by surgery, and they were discharged uneventfully.

승모판막질환에 동반된 심방세동에서 Cox-Maze 술식

김기봉,조광리,안혁,Kim, Ki-Bong,Cho, Kwang-Ree,Ahn, Hyuk 대한흉부심장혈관외과학회 1998 Journal of Chest Surgery (J Chest Surg) Vol.31 No.10

연구배경 : 심장의 구조적 이상을 동반하지 않는 만성 심방세동에 대한 Cox-Maze 술식의 성적은 매우 좋은 것으로 보고되고 있으나 승모판막 질환과 같은 기질적 심장질환에 동반된 심방세동에서의 성적은 다소 떨어지는 것으로 보고되고 있다. 대상 및 방법 : 본 서울대학교병원 흉부외과학 교실에서는 승모판막 질환에 대한 수술과 함깨 시행한 Cox-Maze 술식의 효과와 안전성을 평가하기위해 1994년 4월부터 1997년 10월까지 경험한 70례(남;23, 여;47)를 대상으로 임상 연구를 하였다. 결과 : 70례중 67례가 류마티스성 승모판막 질환이었으며 3례가 퇴행성 질환이었다. 술전 심방세동의 평균 유병기간은 66$\pm$70개월이었다. 15명의 환자에서 과거력상 혈전색전증의 병력이 있었으며 24명의 환자에서 수술중 좌심방내의 혈전이 존재하였다. 과거에 조직판막을 이용한 판막치환술의 병력이 있었던 재수술례가 12례였다. 수술시 대동맥차단시간은 평균 151$\pm$44분이었으며 심폐우회시간은 평균 246$\pm$65분이었다. Cox-Maze 술식과 함께 시행한 수술로는 승모판막 치환술이 19례,승모판막과 대동맥판막 치환술이 14례, 승모판막 치환술과 삼첨판막륜 성형술이 8례, 승모판막 치환술 및 대동맥판막 성형술이 3례있었으며 11례에서는 승모판막 성형술이 가능하였다. 판막치환술과 관상동맥우회술을 같이 시행한 례가 3례있었으며 승모판막 재치환술이 10례, 승모판막 및 대동맥 판막 재치환술이 2례 있었다. 수술사망률은 1.4%(1/70)였다. 수술후 합병증으로는 술후 일시적 심방세동의 재발을 보인 례가 44례였으며 상심실성 빈맥이 10례, 저심박출증후군이 4례, 출혈에 의한 재수술이 4례있었다. 그 밖의 합병증으로는 급성 신부전이 1례, 수술전의 일측 편마비가 악화된 경우가 1례, 그리고 일시적 섬망이 1례 있었다. 생존한 모든 환자를 평균 16.4개월간 외래를 통한 추적관찰하였는데 동기능부전 증후군과 빈맥-서맥 증후군을 보인 2명의 환자에서 영구형 심박동기의 삽입이 필요하였고, 2례만이 현재 심방세동을 보이고 있어서 동율동으로의 전환율은 94.2%였다. 수술만으로 심방세동이 조절되었던 경우가 73.9% 이었고, 수술후 항부정맥제의 병행 투약이 필요했던 경우가 20.3% 이었다. 술후 심방수축력과 기타 심기능의 평가를 위하여 시행한 경흉부 심초음파 검사 소견상 우심방 수축력은 92%에서, 좌심방 수축력의 회복은 53%에서 관찰되었다. 판막재치환술을 시행한 환자들을 첫 수술인 환자들과 비교하였을 때, 심방세동의 유병기간은 재수술한 례에서 통계적으로 유의하게 길었으나 대동맥차단시간, 심폐우회시간, 수술당일의 출혈량, 동율동으로의 전환율등에서는 차이가 없었다. 결론 : 결론적으로 승모판막 질환에 대한 수술과 함께 시행한 Cox-Maze 술식은 비교적 낮은 수술위험도 하에서 높은 동율동 전환률을 보였으며 특히 재수술시에도 비교적 안전하며 매우 효과적이었다. Background: The sugical results of the Cox-Maze procedure (CMP) for lone atrial fibrillation(AF) have proven to be exellent. However, those for AF associated with mitral valve(MV) disease have been reported to be a little inferior. Materials and methods: To assess the efficacy and safety of the CMP as a combined procedure with MV operation, we studied retrospectively our experiences. Between April 1994 and October 1997, we experienced 70 (23 males, 47 females) cases of CMP concomitantly with MV operation. Results: The etiologies of MV disease were rheumatic in 67 and degenerative in 3 cases. The mean duration of AF before sugery was 66$\pm$70 months. Fifteen patients had the past medical history of thromboembolic complications, and left atrial thrombi were identified at operation in 24 patients. Twelve cases were reoperations. Aortic cross clamp (ACC) time was mean 151$\pm$44 minutes, and cardiopulmonary bypass (CPB) time was mean 246$\pm$65 minutes. Concomitant procedures were mitral valve replacement (MVR) in 19, MVR and aortic valve replacement (AVR) in 14, MVR and tricupid annuloplasty (TAP) in 8, MVR with AV repair in 3, MV repair in 11, MVR and coronary artery bypass grafting (CABG) in 2, MVR and AVR and CABG in 1, redo-MVR in 10, redo-MVR and redo-AVR in 2 patients. The rate of hospital mortality was 1.4%(1/70). Perioperative recurrence of AF was seen in 44(62.9%), and atrial tachyarrhythmias in 10(14.3%), low cardiac output syndrome in 4(5.7%), postoperative bleeding that required mediastinal exploration in 4(5.7%) patients. Other complications were acute renal failure in 2, aggravation of preoperative hemiplegia in 1, and transient delirium in 1 patient. We followed up all the survivors for 16.4 months(3-44months) on an average. Sinus rhythm has been restored in 65(94.2%) patients. AF has been controlled by operation alone in 73.9% and operation plus medication in 20.3%. Two patients needed permanent pacemaker implantation; one with sick sinus syndrome, and the other with tachycardia- bradycardia syndrome. Only two patients remained in AF. We followed up our patients with transthoracic echocardiography to assess the atrial contractilities and other cardiac functions. Right atrial contractility could be demonstrated in 92% and left atrial contractility in 53%.We compared our non-redo cases with redo cases. Although the duration of AF was significantly longer in redo cases, there was no differences in ACC time, CPB time, postoperative bleeding amount and sinus conversion rate. Conclusions: In conclusion, the CMP concomitant with MV operation demonstrated a high sinus conversion rate under the acceptable operative risk even in case of reoperation.

흉곽내로 전위시킨 골격근을 이용한 농흉의 외과적 치료

김기봉,박종호,Kim, Gi-Bong,Park, Jong-Ho 대한흉부심장혈관외과학회 1992 Journal of Chest Surgery (J Chest Surg) Vol.25 No.6

From August 1990 through December 1991, 14 patients[all males] underwent int-rathoracic muscle transposition of extrathoracic skeletal muscles to treat empyemas, 6 patients had tuberculous empyemas, 4 had chronic empyemas of unknown etiology, 3 had pos-tpneumonectomy empyemas, and 1 had postlobectomy empyema. 9 patients had associated bronchopleural fistulas, Their ages ranged from 22 to 67 years, with mean age of 45.1$\pm$17. 6[$\pm$S.D] years. The serratus anterior was transposed in 13 patients, the latissimus dorsi in 12. In 11 patients, both the serratus anterior and the latissimus dorsi were transposed. The omental flap also transposed in 3 patients. To reduce the dead space in the thoracic cavity, thr-oacoplasty was also carried out in 10 patients. The number of the partially resected ribs was 3.0$\pm$0.8[$\pm$S.D.]. All operations were single stage procedures, and all wounds were closed primarily, with no permanent tubes or chest wall openings. There was no hospital mortality, and so no subsequent operation has been required. Follow-up of the patients ranged from 5 to 16 months with a mean of 9.2$\pm$3.1[$\pm$S.D] months, All the patints had no further signs or symptoms of the original infection after discharge. We conclude that intrathoracic transposition of extrathoracic skeletal muscle is an excellent method of treatment for persistent, life-threatening intrathoracic infections.

관상동맥우회술 후 1년 개존성에 관한 연구

김기봉,김현조,성기익,Kim, Gi-Bong,Kim, Hyeon-Jo,Seong, Gi-Ik 대한흉부심장혈관외과학회 1997 Journal of Chest Surgery (J Chest Surg) Vol.30 No.12

1994년 7월부터 1995년 8월까지 서울대학교병원 흉부외과에서 시행한 관상동맥 우회술 78례 중 49례 (62,8%)에서 수술 1년 후 관상동맥 조영술을 시행하여 이식 혈관의 개존성을 조사하였으며, 수술 전,후 및 수술과 관련된 여러 위험 요소들이 개존성에 미치는 영향에 대하여 분석하였다. 관상동맥 우회술 후 평균 13.4$\pm$2.1개월 째에 관상동맥 조영술을 시행하였다. 내유동맥으로 문함을 시행한 60개소 중 3개소에서 string sign을 보였으나, 폐쇄 없이 전례에서 개존성이 유지되었으며, 요골동맥으로 문합을 시행한 4개소는 모두 개존성이 유지되었다. 복제정맥으로 문합을 시행한 81개소 중 69개소(85.2%)에서 개존성이 유지되었으며, 12개 소(14.8%)에서 폐쇄되었다. 개존성에 미치는 위험요소로 수술 전,수술 중 그리고 합병증 등의 수술 후 요소로 나누어 일원적 및 다원적으로 분석하였으며, 내유동맥의 협착 과 복재정맥의 개존성, 폐쇄에 미치는 요소들을 분석하였다. 내유동맥은 환자의 연령(60세 이상),수술 후 대동맥 내 풍선펌프의 삽입,수술 후 출혈, 및 급성신부전 등 합병증이 이식 혈관의 협착과 관련된 위험 인자였으며, 복제정맥은 우회술을 시\ulcorner 받은 관상동맥의 직경이 1.5mm 이하인 경우가 이식 혈관의 폐쇄 위험성과 관련된 위험 인자로 분석되었다(p<0.05). 관상동맥 우회술 1년 후 이식 혈관의 개존성은 내유동맥이 복재정맥보다 우수함을 보였으며 환자 연령 수술 후 대동맥 내 풍선펌프의 삽입여부, 출혈, 급성 신부전 등의 합병증 및 문합된 관상 동맥의 직경 등이 개존에 관련된 요소로 분석되었다. 이러한 결과를 토대로 수술 후 이식혈관의 폐쇄 여부에 대한 11측과 수술 방법이나 수술 후 환자의 추적 관찰에 도움을 줄 수 있으리라 생각된다. Between July 1994 and August 1995, 78 patients underwent coronary artery bypass graft at Seoul National University Hospital. Coronary angiogram was performed one year after coronary artery bypass graft in 49 patients(62.8%) for evaluation of the graft patency and analysis of the risk factors for graft occlusion. The patency rates of both the internal mammary artery and the radial artery grafts were 100% , although three internal mammary artery grafts(5.0%) were narrowed(string sign). And that of the saphenous vein grafts were 85.2%. Multivariate analysis for the preoperative, operative, and postoperative factors was done between the widely patent and the narrowed internal mammary artery graft groups, and between the patent and the occluded saphenous vein graft groups by the general linear models procedure. Patient's age($\geq$60 years), postoperative intraaortic balloon pump insertion, bleeding, and acute renal failure were found to be the significant risk factors for internal mammary artery graft narrowing, and coronary artery size(< 1.5 mm) was the significant risk factor for the saphenous vein graft occlusion (p<0.05) . This study confirms that the arterial graft is superior to the vein graft at one-year patency rate, and suggests the risk factors for graft occlusion during the first postoperative year. Knowledge of this study may provide a basis for estimating the risk factors for graft occlusion, and thereby modifying surgical strategy and postoperative surveillance.