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초전도 케이블용의 냉매인 극저온 액체 기체의 전기적 성질
김상현,마대영,김현희 국립경상대학교 공과대학 부설 첨단소재연구소 1992 尖端素材 Vol.2 No.-
Recently, Superconducting cable has attracted a great deal of interest from the viewpoint of energy saving. One of the most important and difficult problems to be solved to assure the high reliability and long life of cable is breakdown at cryogenic temperatures. In this paper, we will report on the breakdown characteristics of cryogenic liguid and gas for superconducting cable. In cryogenic gas N₂(300K-93K), the breakdown voltage depends on gas density and temperature. And it is obeyed by Paschen's law. But low breakdown voltage of cryogenic gas N₂requires caution in the design. in cryogenic liquid N₂(77K), the breakdown voltage depends on gas bubble.
Dae Sung Ma,Tae-Hyun Kim,Min Ae Keum,Dong Kwan Kim,Suk-Kyung Hong 대한중환자의학회 2015 Acute and Critical Care Vol.30 No.1
Anaphylactic reaction during the perioperative period typically exhibits rapid onset, varying clinical manifestations, and an expected mortality rate of 1.5-9%. Neuromuscular blocking agents are the leading cause of perioperative anaphylaxis. Here, we report a severe case of anaphylaxis that developed in a 66-year-old man due to cisatracurium administration. And he was successfully managed by extracorporeal membrane oxygenation. Cardiopulmonary resuscitation was performed by extracorporeal membrane oxygenation, and the patient was successfully weaned off 24 hours later.
Delayed Surgical Management of Traumatic Pseudoaneurysm of the Ascending Aorta in Multiple Trauma
( Dae Sung Ma ),( Sung Jin Kim ),( Seok Joo ),( Sung Youl Hyun ),( Yang Bin Jeon ) 대한외상학회 2018 大韓外傷學會誌 Vol.31 No.1
Traumatic blunt aortic injury especially on proximal ascending aorta is a rare injury with a few reports. Generally emergency surgical management was performed. In this case, however, in multiple trauma with brain injury, emergency surgical management of aortic injury might result in unexpected secondary injury of the brain. Herein, we report a case of a 33-year-old man who was driving a truck was injured in a head-on collision. Evaluation revealed a pseudoaneurysm on his ascending aorta concomitant with epidural hemorrhage. He was treated by surgical management of his ascending aorta after 3 days from accident. There were no postoperative and neurologic complications and the patient was discharged after 18 days.
Upper Extremity Deep Vein Thrombosis after Clavicle Fracture and Immobilization
( Sung Jin Kim ),( Dae Sung Ma ),( Sung Youl Hyun ),( Yang Bin Jeon ),( Seok Joo ),( Ahram Han ) 대한외상학회 2018 大韓外傷學會誌 Vol.31 No.1
Upper extremity deep vein thrombosis (DVT) is an unusual condition compared to lower extremity DVT, and it represents about 10% of all DVTs. We report a case of upper extremity DVT after clavicle fracture and immobilization.
( Dae Sung Ma ),( Gil Jae Lee ) 대한외상학회 2021 大韓外傷學會誌 Vol.34 No.1
Purpose: Nutritional therapy in the intensive care unit is an essential factor for patient progress. The purpose of this study was to compare resting energy expenditure (REE) calculated by prediction equations (PEs) to the REE measured by indirect calorimetry (IC) in trauma patients. Methods: Patients admitted to the trauma intensive care unit who received mechanical ventilation between January and December 2015 were enrolled. REE was measured by IC (CCM Express, MGC Diagnostics) and calculated by the following PEs: Harris-Benedict, Fleisch, Robertson and Reid, Ireton-Jones, and the maximum value (25 kcal/kg/ day) of the European Society for Clinical Nutrition and Metabolism (ESPEN). All patients were ventilated at a fraction of inspired oxygen (FiO<sub>2</sub>) below 60%. Results: Of the 31 patients included in this study, 24 (77.4%) were men and seven (22.6%) were women. The mean age of the patients was 49.7±13.2 years, their mean weight was 68.1±9.6 kg, and their mean Injury Severity Score was 26.1±11.3. The mean respiratory quotient on IC was 0.93±0.19, and their mean FiO<sub>2</sub> was 38.72%±6.97%. The mean REE measured by IC was 2,146±444.36 kcal/day, and the mean REE values calculated by the PEs were 1,509.39±205.34 kcal/day by the Harris and Benedict equation, 1,509.39±154.33 kcal/day by the Fleisch equation, and 1,443.39±159.61 kcal/day by the Robertson and Reid equation. The Ireton-Jones equation yielded a higher value (2,278.90±202.35 kcal/ day), which was not significantly different from the value measured using IC (p=0.53). The ESPEN maximum value (1,704.03±449.36 kcal/day) was lower, but this difference was likewise not significant (p=0.127). Conclusions: The REE measured by IC was somewhat higher than that calculated using PEs. Further studies are needed to determine the proper nutritional support for trauma patients.
( Dae Sung Ma ),( Yang Bin Jeon ) 대한외상학회 2021 大韓外傷學會誌 Vol.34 No.2
Purpose: This study investigated the clinical outcomes of trauma patients with blunt thoracic aortic injuries at a single institution. Methods: During the study period, 9,501 patients with traumatic aortic injuries presented to Trauma Center of Gil Medical Center. Among them, 1,594 patients had severe trauma, with an Injury Severity Score (ISS) of >15. Demographics, physiological data, injury mechanism, hemodynamic parameters associated with the thoracic injury according to chest computed tomography (CT) findings, the timing of the intervention, and clinical outcomes were reviewed. Results: Twenty-eight patients had blunt aortic injuries (75% male, mean age, 45.9±16.3 years). The majority (82.1%, n=23/28) of these patients were involved in traffic accidents. The median ISS was 35.0 (interquartile range 21.0-41.0). The injuries were found in the ascending aorta (n=1, 3.6%) aortic arch (n=8, 28.6%) aortic isthmus (n=18, 64.3%), and descending aorta (n=1, 3.6%). The severity of aortic injuries on chest CT was categorized as intramural hematoma (n=1, 3.6%), dissection (n=3, 10.7%), transection (n=9, 32.2%), pseudoaneurysm (n=12, 42.8%), and rupture (n=3, 10.7%). Endovascular repair was performed in 71.4% of patients (45% within 24 hours), and two patients received surgical management. The mortality rate was 25% (n=7). Conclusions: Traumatic thoracic aortic injuries are life-threatening. In our experience, however, if there is no rupture and extravasation from an aortic injury, resuscitation and stabilization of vital signs are more important than an intervention for an aortic injury in patients with multiple traumas. Further study is required to optimize the timing of the intervention and explore management strategies for blunt thoracic aortic injuries in severe trauma patients needing resuscitation.
( Dae Sung Ma ) 대한외상학회 2021 大韓外傷學會誌 Vol.34 No.2
Purpose: The present study aimed to analyze the effect of trauma-related shock on myocardial function in the early stages of trauma through transthoracic echocardiography (TTE) findings. Methods: We performed a retrospective review and analysis of the medical records of patients aged ≥18 years who were evaluated by TTE within 2 days of admission for trauma-related shock (n=72). Patients were selected from a group of 739 patients admitted with trauma-related shock between January 2014 and December 2016. Results: The incidence rate of myocardial dysfunction in the left ventricle (LV) was 6.8% (5/72), with rates of 7.7% (4/52) in the thoracic injury group and 5.0% (1/20) in the non-thoracic injury group. In the diastolic function of LV, relaxation abnormality was present in 55.8% (29/52) of patients in the thoracic injury group and 50% (10/20) of patients in the non-thoracic injury group. Conclusions: This study may suggest that traumatic shock without thoracic injury may influence myocardial function in the early stages after trauma. Therefore, evaluation of myocardial function may be needed for patients experiencing shock after trauma, regardless of the presence of thoracic injury.
마대성(Dae-Sung Ma),유진호(Jin-Ho You),김병기(Byung-Gi Kim) 한국정보과학회 1998 한국정보과학회 학술발표논문집 Vol.25 No.2Ⅲ
본 논문은 병렬 프로그램의 성능 분석을 위한 성능 감시기에서 가시화층의 일반화된 뷰를 설계하고 구현하였다. 대부분의 성능 감시기는 하드웨어에 의존적인 특성화된 뷰를 제공함으로서 이식성이나 확장성이 부족하다. 일반화된 뷰를 제공하는 성능 감시기는 데이터 필터층에서 필터링된 성능 분석 데이터를 이용하여 프로그래머가 정의한 데이터의 범의에 따라 뷰를 스스로 확장할 수 있다. 또한, CallBack 기능을 제공하여 관심 있는 데이터를 쉽게 볼 수 있다. 프로그래머는 성능 감시기의 일반화된 뷰를 이용하여 다양한 형태의 성능 분석결과를 볼 수 있다.
흡수기 형상과 반사경 배치에 따른 접시형 집열기 성능평가
마대성(Ma Dae-Sung),김용(Kim Yong),서태범(Seo Tae-Beom),강용혁(Kang Yong-heack) 한국태양에너지학회 2006 한국태양에너지학회 학술대회논문집 Vol.- No.-
This article presents an analysis of a dish solar collector. This project investigates a perfect mirror(1.5 m diameter) and 5 arrays of 12 identical spherical mirror facets(0.4 m diameter). Five equal area(1.5 ㎡) with spherical reflector array configurations are designed and compared; Perfect mirror and 2AND4 INLINE, 2TOP, INLINE, STAGGERED. The surface reflectivity of each mirror varies from 0.75 to 0.95 and a focal length of the mirrors is 1.5 m. Also, this project has three different receivers(dome type, conical type, cylindrical type). The surface absorptivity and aperture diameter of the receivers is 0.9 and 0.15m, respectively. The incident solar flux is predicted using TracePro. Based on the ray tracing analysis, the performance of the dish solar collectors are estimated with different mirror arrays and receiver shapes. The results show that the dome type has the best performance in receiver shapes and the 2AND4 INLINE has the best performance in mirror arrays except perfect mirror.