심근내 총상 파편 환자의 치험 1 례

오중환,원준호,박승일,서재정,황정주 대한외상학회 2000 大韓外傷學會誌 Vol.13 No.2

Gunshot injuries to the heart, lung and great vessels are rare, but gunshot injuries are increasing with increased use of guns in hunting. We experienced a patient whose heart had been injured in a hunting accident and report with literature reviews. A 43-year-old man was admitted to our hospital with gunshot wounds to the scalp, face, upper extremity, and anterior chest. Computed tomography and echocardiography revealed several pellets in the chest wall, epicardium, and myocardium of the right ventricle. The pellets in the chest wall and epicardium were removed by a left thoracotomy, but the pellet in the myocardium of the right ventricle was not removed. The patient was discharged from the hospital without any significant residual complications and has been followed up for 9 months after discharge.

계기비행 시뮬레이터에서 비행 임무의 평가 및 구현

황수찬(Soo Chan Hwang),백중환(Joong Hwan Baek) 한국항행학회 2000 韓國航行學會論文誌 Vol.4 No.1

Instrument flight simulators are used for training the interpretation and operation techniques for all kinds of aircraft instruments, cockpit procedures, etc., in order that pilots cope with the situations which can be occurred in actual flight. However, the simulators developed so far are concerned about operating in same environment to actual aircraft. And little researches concentrate on developing systematic training system for basic tasks and takeoff-landing procedures, and automatic evaluation methods on the training results. Therefore, in this paper, we propose implementation and evaluation methods for flight tasks such as tasks in flight, takeoff-landing procedures and course flight.

보이스 코일 모터의 정밀위치 제어를 위한 수학 모델링 및 검증

황진동(J. D. Hwang),김주현(J. H. Kim),곽용길(Y. K. Kwak),김선호(S. H. Kim),안중환(J. H. Ahan) 한국정밀공학회 2005 한국정밀공학회 학술발표대회 논문집 Vol.2005 No.10월

Voice Coil Motor is used linear motion actuator system that require precision positioning control. In order to control precision positioning of voice coil motor, Mathematical model of voice coil motor is needed. Mathematical model is obtained by combining voice coil motor"s equation of motion with the equation of circuit and characteristic of voice coil motor. The induced model can predict output displacement according to duty ratio and amplitude. The model is verified by experimental test. Simulated results have tracking errors of less than 10 percent of experimental results.

양돈 슬러리에 첨가된 발효탄수화물의 종류별 악취물질 농도 비교

황옥화,양승학,전중환,곽정훈,최동윤,양승봉,김두환,조성백,Hwang, Ok Hwa,Yang, Seung Hak,Jeon, Jung Hwan,Kwag, Jeong Hoon,Choi, Dong Yun,Yang, Seung Bong,Kim, Doo Hwan,Cho, Sung Back 한국축산환경학회 2013 한국축산시설환경학회지 Vol.19 No.1

Slurry treatments included peanut shell, palm golden fiber, almond hull, which was added 2% of the amount of slurry, and non-treatment control (n=4 each group). Levels of odorous compounds were measured from the liquid slurry incubated in $20^{\circ}C$ for 2 wk in chamber whose structure is similar to slurry pit. Concentration of phenols and indoles was higher (p<0.05) in control (48.4, 4.0 ppm) compared to almond hull (31.5, 1.4 ppm) or palm golden fiber (29.1, 1.6 ppm) group. Short chain fatty acid (SCFA) level was lowest (p<0.05) in control (2,121 ppm) but highest in peanut shell group (3,640 ppm). Branched chain fatty acid (BCFA) concentration was highest (p<0.05) in peanut shell (296 ppm), but lowest in almond hull (90 ppm). Taken together, concentration of odorous compounds was decreased by addition of almond hull in pig slurry by which crude fiber and non-digestible fiber (NDF) may act as a carbon source.

양돈 슬러리에 첨가된 악취저감물질 수준별 휘발성 지방산과 휘발성 유기화합물 농도 비교

황옥화,양승학,전중환,김중곤,최동윤,조성백,Hwang, Ok-Hwa,Yang, Seung-Hak,Jeon, Jung-Hwan,Kim, Jung-Kon,Choi, Dong-Yun,Cho, Sung-Back 한국축산환경학회 2013 한국축산시설환경학회지 Vol.19 No.2

This study was to investigate the effect of addition levels of odor reducing contents on reducing the concentration of odorous compounds. Slurry treatments included three levels mixture of horseradish powder (HP), mushroom waste (MW) and probiotics powder (PP), and non-treatment control (n=4 each group). Levels of odorous compounds were measured from the liquid slurry incubated in room temperature ($20{\sim}25^{\circ}C$) for 2 wk in chamber whose structure is similar to slurry pit. Concentration of phenols and indoles was lower (p<0.05) in level 1, which was mixed HP 0.01%, MW 0.4% and PP 0.004% (98.69, 1.87 ppm) compared to control. Short chain fatty acid (SCFA) and branched chain fatty acid (BCFA) was lowest (p<0.05) level 1 (6,557, 1675 ppm). Taken together, lower level are effective in reducing odorous compounds in pig slurry.

비행 운동 시뮬레이션을 위한 좌표계 변환

백중환,황수찬,김칠영 한국항행학회 1999 韓國航行學會論文誌 Vol.3 No.2

비행 시뮬레이터는 엔진 모듈, 항법장치 모듈, 계기 모들로 구성된다. 여기에는 두 가지의 문제점을 가지고 있다. 첫째는, 각 모듈별로 사용하는 좌표계가 서로 다르다는 점이다. 이를 해결하기 위해 본 논문에서는 각기 독자적인 좌표계를 일치시키기 위한 방법을 고안하였다. 둘째는, 지구 형태가 완전한 구 모양을 따르고 있다고 가정하고 구삼각공식을 이용하여 거리와 방위각을 계산하게 되면 많은 연산량이 요구된다. 본 논문에서는 근거리 비행시 구 삼각공식 대신 평면 근사화 방식을 사용함으로써 우수한 결과를 얻음을 확인하였따. 연산 속도는 구 삼각공식 사용시 4.95 × 10^-4초에서 평면 근사화 방식을 사용시 1.648 × 10^-4초로 향상됨을 확인하였다. A flight simulator is composed of engine, navigation systems and instrument modules. However, two problems exist here. First, the coordinate of each independent module is not same. To solve this problem, we design a method that mutual coordinates are capable of transformation each other. Second, the distance and bearing between two points on the earth are computed in a sphere shape using the spherical trigonometry. However, the computing time is very sever. In this paper, we project the sphere into the planar to reduce the computing time. An experimental result shows that the performance of the proposed method is excellent to both distance and bearing calculations in close region. Also, the computing time is reduced from 4.95 × 10^-4 seconds to 1.648 × 10^-4 seconds.

임상 ; 선택적 제왕절개술로 출생한 재태연령 35주 이상신생아의 재태연령에 따른 호흡기 이환율

황진솔 ( Jin Sol Hwang ),김세연 ( Sae Yun Kim ),신승한 ( Seung Han Shin ),이주영 ( Ju Young Lee ),김이경 ( Ee Kyung Kim ),김한석 ( Han Suk Kim ),최중환 ( Jung Hwan Choi ) 대한주산의학회 2013 Perinatology Vol.24 No.4

목적: 선택적 제왕절개술로 태어난 재태연령 35주 이상의 신생아에서 재태연령에 따라 호흡기 이환율의 차이가 있는지 알아보고자 하였다. 방법: 2011년 1월부터 2012년 12월까지 서울대학교병원에서 선택적 제왕절개술로 태어난 재태연령 35주 이상의 신생아 443명을 대상으로 후향적 고찰을 통해 조사하였다. 대상 신생아들을 재태연령에 따라 네 군(35+0-36+6주, 37+0-37+6주, 38+0-38+6주, 39+0-40+6주)으로 나누어 호흡기 이환율을 비교하였다. 결과: 1분, 5분 아프가 점수는 후기 조산아(35-36주)군이 만삭아군에 비하여 낮았고, 전자간증 산모의 비율은 재태연령이 증가함에 따라 감소하는 경향을 보였다. 재태연령에 따라 네 군으로 나누어 비교하였을 때, 산소 투여 여부, 24시간 이상 산소 투여, 흉부방사선 촬영, 신생아 일과성 빈호흡, 신생아 중환자실 전동, 기관내 삽관, 기계적 환기요법 적용등 모든 항목에서 유의한 차이가 있었다(P<0.05). 재태연령간 호흡기 이환율을 비교하였을 때, 재태연령 35-36주인 군은 38주인 군보다 신생아 일과성 빈호흡(122.5배), 신생아 중환자실 전동(54.0배), 기계적 환기요법 적용(99.5배) 의 위험도가 높았으며, 재태연령 37주인 군도 38주인 군보다 신생아 일과성 빈호흡(8.8배), 신생아 중환자실 전동(5.3배), 기계적 환기요법 적용(8.4배) 의 위험도가 높았다(P<0.05). 재태연령 38주인 군과 39-40주인 군 사이에는 호흡기 이환율의 유의한 차이가 없었다. 결론: 선택적 제왕절개술의 시기를 재태연령 38주 이후로 늦추는 것이 신생아 호흡기 이환율을 줄이는데 도움이 될 수 있을 것으로 생각된다. Purpose: We evaluate respiratory morbidities in infants beyond 35 weeks of gestation born via elective cesarean section by gestational age. Methods: This is a retrospective study of 443 infants who were born at Seoul National University Hospital by elective cesarean section beyond 35 weeks of gestation from January 2011 to December 2012. We compared respiratory morbidities in four groups classified by gestational age (35+0-36+6 weeks, 37+0-37+6 weeks, 38+0-38+6weeks, 39+0-40+6 weeks). Results : There were significantly lower Apgar scores in the late-preterm infant group (35-36 weeks) compared to other term infant groups and the proportion of infants born from mothers with preeclampsia gradually decreased as gestational age increased. There were significant differences in O2 supplement, duration of O2 (>24hours), checked chest radiography, transient tachypnea of newborn (TTN), transfer to neonatal intensive careunit (NICU), end otracheal intubation, and ventilator uses including nasal continuous positive airway pressurein four groups (P <0.05). By logistic regression analysis, compared to births at 38 weeks, births at 35-36 weeks and at 37 weeks were associated with an increased risk of respiratory morbidities [odds ratios (OR) and 95%confidence intervals (CI) for births at 35-36 weeks, 122.5 (17.4-863.4) for TTN; 54.0 (10.1-289.4) for transfer to NICU; 99.5 (14.9-666.2) for ventilator apply; OR and 95% CI for births at 37 weeks, 8.8 (1.6-50.1) for TTN;5.3 (1.1-24.7) for transfer to NICU; 8.4 (1.5-47.7) for ventilator apply; P <0.05]. There were no significant differences in respiratory morbidities between births at 38 weeks and births at 39-40 weeks. Conclusion: Postponing the timing of elective cesarean section to beyond 38 weeks of gestation would be helpful in reducing the neonatal respiratory morbidities.

보이스 코일 액츄에이터의 PWM 제어에서 듀티비-변위 모델 연구

황진동(Jin-Dong Hwang),곽용길(Yong-Kil Kwak),김주현(Ju-Hyun Kim),김선호(Sun-Ho Kim),안중환(Jung-Hwan Ahn) 한국기계가공학회 2007 한국기계가공학회지 Vol.6 No.2

Voice coil actuator is used linear motion system that requires precision positioning control. In order to control precision positioning of voice coil actuator, relation model between duty ratio and moving displacement of voice coil actuator is needed. This paper present a duty ratio - displacement model in PWM control of voice coil actuator. Transfer function of voice coil actuator is obtained by combining voice coil motor's equation of motion with the equation of circuit and characteristic of voice coil motor. Consider to initial condition of velocity and current, transfer function is transformed mathematical model. The induced model can predict output displacement, velocity and current according to duty ratio and amplitude. The model is verified by experimental tests such as velocity and displacement response of voice coil motor. Simulated results have tracking errors of less than 10 percent of experimental results.

자기변형재료를 이용한 초정밀 액추에이터개발

황진동,김선호,안중환 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.5월

VCM을 이용한 비원형 형상 가공의 궤적 오차 시뮬레이션

황진동(J. D. Hwang),곽용길(Y. K. Kwak),김선호(S. H. Kim),안중환(J. H. Ahan) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월

A Simulation model is developed to minimize the path tracking errors when the non-circular cutting is done by a VCM(voice coil motor) driven tool. The relationship between PWM(Pulse Width Modulation) duty ratio and velocity of voice coil motor is theoretically derived from combining the circuit equation for the coils and the motion equation for the magnetic rod of the voice coil motor. The path tracking errors are showed differently according to the rotational speed, the number of segments and the control period in digital control. Given a required accuracy in the non-circular cutting, the optimal values for those parameters are determined based on the developed simulation model.