가토 외고정 모델을 이용한 치밀체형 세라믹스의 골결합능 평가

이재협,이동호,이재학,공현식,안영준,류현승,서준혁,홍국선,김환,장봉순,이춘기 대한정형외과연구학회 2003 대한정형외과연구학회지 Vol.6 No.2

소아 심장 CT 검사시 Dual Source CT의 High pitch mode를 이용한 선량감소에 관한 연구

이예나(Ya Na Lee),강헌효(Heon Hyo Kang),손성실(Sung Sil Son),박찬혁(Chan Hyuk Park),현진경(Jin Kyung Hyun),신명호(Myung Ho Shin),김준혁(Jun Hyuk Kim),강동원(Dong Won Kang) 대한CT영상기술학회 2012 대한CT영상기술학회지 Vol.14 No.1

I. Purpose This study examines if accurate images can be realized with less dose than sequential mode, one of the existing methods applying DSCT’s high-pitch mode in pediatric cardiography. II. Materials and Methods For 20 patients who came to our hospital from Jan. 1 to Jun. 30, 2011, a test was carried out using MDCT 128 channel dual source; Somatom Definition Flash (Siemens Medical System: Germany). As the test method, the veins of the lower limbs of the patients were secured and contrast medium of 7ml was injected at 0.3ml/s anda CT scan was carried out about 36 s. later. Af first, sequential mode was used, and then high-pitch mode was followed as follow-up examination. The DLP (Dose Length Product) provided by the equipment and effective dose were compared for the assessment of the dose exposed to the patients, after the CT scan. The effective does was calculated by multiplying children’s chest index: 0.021 of the effective dose rate of EUR16262 (European Guide) to DLP value. The images scaned in high-pitch method were compared and assessed quantitatively by a heart decoding specialist and 2 radiologists if the typical diseases of pediatric cardiacs such as coarctation of aorta, atresia of the pulmonary artery and Tetralogy of Fallot can be assessed. III. Results When it was compared to sequential mode, one of the existing cardiography, the effective dose exposed to the patient had decrease by 32% in high-pitch mode. As a result of a comparison with imaging assessment, it was also evaluated as a better imaging than sequential mode IV. Conclusion Pediatric Cardiography using high pitch in Dual source MDCT showed superior effects on the reduction of exposed does than sequential mode, which is considered a useful testing method. 목적 본 연구에서는 소아 심장 검사 시 DSCT의 High-pitch mode를 적용하여 기존의 검사방법 중 하나인 Sequential mode보다 적은 선량으로도 정확한 영상을 구현할 수 있는지 알아본다. 대상 및 방법 2011년 1월 1일부터 6월 30일까지 본원에 내원한 20명의 환자를 대상으로 하여 MDCT 128 channel dual source; Somatom Definition Flash(Siemens medical system: Germany) 장비를 사용하여 검사를 시행하였다. 검사방법은 환자의 하지에 정맥을 확보하고 조영제를 0.3 ml/s로 7ml를 주입한 후 36초 후에 CT검사를 하였다. 처음에는 Sequential mode로 검사한 후 추적 검사할 땐 High-pitch mode로 검사한다. 환자가 받은 피폭선량의 평가는 선량평가는 CT검사 후 장비에서 제공하는 DLP(dose length product)와 유효선량(effective dose)를 비교하였다. 유효선량은 DLP 값에 EUR16262(European Guide) 유효선량비 중 소아 흉부 지수 0,021을 곱하여 계산하였다. 검사한 영상을 심장 판독 전문의 1명과 방사선사 2명이 high-pitch mode로 검사한 영상을 소와 심장의 대표적 질환인 대동맥협착증, 폐동맥 폐쇄증, 팔로씨 사증을 평가할 수 있는지 비교하여 정성적으로 평가하였다. 결과 기존의 심장 검사방법 중 하나인 Sequential mode와 비교했을 때 High pitch mode로 검사했을 때에 32%의 선량 감소 효과가 있었다. 또한 영상 평가 비교 결과 Sequential mode 보다 좋은 영상으로 평가되었다. 결론 Dual source MDCT로 소아심장 검사를 할 때 high pitch mode를 이용하면 sequential mode로 검사했을 때보다 환아가 받는 피폭선량은 낮고 더 우수한 영상을 획득하여 심장질환을 진단하는데 유용한 검사법으로 사료된다.

용융환원로 배기조성을 이용한 철광석의 예비환원 속도론

이준혁,김성수 嶺南大學校 工業技術硏究所 1995 工業技術硏究所論文集 Vol.23 No.1

Using CO-H₂O and CO-CO₂-H₂O gas mixtures which are a portion of exhaust gas from Bath Smelter, the effect of H₂O partial pressure on the prereduction kinetics of Iron oxide was investigated. H₂O partial pressure in the gas mixture was allowed to change from 0%, 5%, 10% to 15%. Reduction experiments were made at the temperatures of 800, 900, 1000℃ respectively for acid and basic pellets. When the acid pellet was reduced by CO-CO₂-H₂O mixing gas, the incubation period appeared at approximate 27% reduction degree at which Iron oxide was thought to remain as wustite. As the reduction temperature decreased, the incubation period was longer, and because the poisoning effect of H₂O took place at the reduction step of FeO to Fe, it could be said that the total reduction proceeded by the next two steps; Fe₂O₃ to FeO, and FeO to Fe. For the reduction of basic pellet, the poisoning effect of H₂O was remarkable at the reduction stage of Fe₂O₃ to FeO, and reaction rate became faster around 35% reduction degree than that of initial stage. From the experimental result, it was found that the poisoning effect of H₂O for the basic pellet appeared at the reduction step of Fe₂O₃ to FeO, but this effect appeared at the reduction step of FeO to Fe for the acid pellet. The kinetic data were satisfactorily fitted to homogeneous model from which the apparent rate constant(k) was calculated. With the apparent rate constant and following equation, H₂O poisoning effect could be quantified as a term of ???. ???.

대구광역시 소재 대형할인점의 여성고객편의시설에 대한 현황조사 및 분석에 관한 연구

이경희,최영오,박준웅,최무혁 대한건축학회 2004 대한건축학회논문집 Vol.20 No.4

As educational level of women has become strong and various job classifications have been created, social climate has been changed to give important part to women. Only construction, however, seems to be not melting this social climate. In other words, while things are trending toward making of exclusive spaces or The Facility for Female Customers, this Facility has been designed without care for women. So this study is to find out the existing conditions of The Facility for Female Customers through the survey and then analyzes degree of satisfaction of Female Customers and Zoning Types of The Facility for Female Customers by survey. This study focused on Large-scale Discount Stores in Daegu. The result of The Improvement of the Current Facility for Female Customers in Large-scale Discount Stores can be summarized as follows : ① The Attached Parking Space in Large-scale Discount Stores should be more safe for Female Customers through improvement of illuminance of artificial lighting and reasonable arrangement of security. ② The Restroom for Women should be designed that the facility and space are more expanded than the present state. ③ The Nursery Room should be designed to take privacy that the sense of sight and hearing will be guaranteed. ④ The Indoor Playground should be set up and managed installing safety equipment and arranging security focused on free Indoor Playground. ⑤ The Culture Center in Large-scale Discount Stores should be used lively as facility for life-long education of residents. ⑥ The Facilities for Female Customers should be connected closely each other through considering women's behavior.

어머니가 지각한 아버지의 양육참여도 및 어머니의 양육효능감과 유아의 또래놀이행동의 관계

이충량, 문혁준 가톨릭대학교 생활과학연구소 2011 생활과학연구논집 Vol.31 No.1

적외선 영상 획득을 위한 직육면체형 지상 표적에 대한 열해석 연구

이상엽,최준혁,박원희,김태국 중앙대학교 기술과학연구소 2003 기술과학연구소 논문집 Vol.33 No.-

육면체형 지상 표적의 적외선 영상을 획득하기 위하여 표적을 등성질의 사각형 격자로 세분하여 열해석을 수행하였다. 열해석을 위하여 전도, 대류 및 복사를 고려하였으며, 태양복사에 의한 입사량은 LOWTRAN 7을 이용하여 산출하였다. 다양한 조건에서 열해석을 수행하여서 물리적 온도를 산출하였으며, 이는 열상장비에서의 적외선 화상을 시뮬레이션을 하는데 기본 도구로 사용될 수 있다. The thermal modeling of a 3D ground target by considering the solar radiation through various atmospheric conditions and the eonvection by the atmospheric air is studied. Since the heat is dissipated by the conduction within the target, the target is subdivided into small rectangular elements to determine the local temperature distribution on the target which is the most important information in generating the infrared images from the target. For the thermal modeling, simple experimental models are applied for the conduction within the target and the convection by the atmospheric air and a realistic model called as the LOWTRAN 7 in used to determine the solar incidence on the target after passing through the atmospheric layer. The physical temperature distribution on the target is determined for various atmospheric conditions from the thermal modeling, and these data can be utilized for various purposes such as the infrared image generation of the target considered.

음주 외상 환자

이성우,문준동,최성혁,문철규,홍윤식 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: We studied the incidence of trauma caused by alcohol related accidents, and the effects that alcohol has on the occurrence, the extent, and the outcome to the patient. Methods: In our study we studied trauma patients excluding pediatric patients(15 years old and under) who came to the Emergency department of Korea University Medical School Anam Hospital from the 1st of January 1996 to 30th of June 1996, looked into their medical records, and studied the records in a retrospective manner. The trauma patients were devided into two groups, a) alcohol-related and b) alcohol-non-related. The two groups were then subdivided according to their sex, age, the time they came in, the anatomical part of the trauma, the mechanism of their injury, the extent of the injury, the length of their hospital stay, the length of their ED stay and were seperately compared and analyzed. Statistically, ANOVA and logistic regression analysis using SAS were used in the study and then was assessed in Chi-square analysis methods. Results: The total of the trauma patients, added up to 832 people, 577:male and 255:female. Among this sum, 163 trauma patients were alcohol related(male:127 & female:36). 115 people were in the age group of 21-40. Compared to the non-alcohol related trauma group, the alcohol-related group had more facial & scalp injuries and tended to come in the hours between 0-6 AM. The cause of the injuries were mostly by fist-fighting and suicide, compared to mostly accidental-slipping injuries in the non alcohol-related group. There were no difference in the degree of the injury(ISS) and the length of hospital stay between the two groups, whereas the length of the stay at the ED was longer to the alcohol-related trauma patients. Conclusion: Alcohol related trauma patients were mostly in their 20s and 30s, came to the hospital at a late time and the reason for their visit were mostly because of fist fighting. In the Emergency department, because prompt and correct diagnosis is quite difficult to make in this group, their ED stay tended to be longer. We can conclude that measuring the blood alcohol level of these patients, continuing the psychological therapy and educating people is needed.

ADSL망에서 가입자 수에 따른 지연 시간 분석

이준혁,홍석원 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

Asymmetric Digital Subscriber Line(ADLS) is considered as one of the promising technologies to provide high-speed Internet access to subscribers. The speed that subscribers can achieve in the ADSL access network varies depending on the various factors. One of the factors is the dimensioning of the access network which is determined by how many users are connected to one DSLAM. In this paper we describe the architecture of ADSL access network and network constituents, and explain two connection models and related protocols for Internet service provisioning. Then we establishes the simulation model where each subscriber connects to a remote server by HTTP connection and download a page on each request. In this paper we analyze the delay and link utilization depending on the number of subscribers, download file sizes, and server capacities. We use OPNET for simulation.

경사 터널내 화재시 임계속도에 관한 실험적 연구

이성룡,김충익,유홍선,김혁순,전명배 한국화재소방학회 2004 한국화재소방학회논문지 Vol.18 No.1

본 연구에서는 터널 화재시 임계속도에 대한 터널 경사의 영향을 파악하기 위하여 축소모형 실험을 실시하였다. Froude 상사를 사용하여 1/20로 축소된 모형터널에서 실험을 실시하였으며, 가연물질로는 에탄올 사용하였다. 정사각형 풀을 사용하였으며 발열량은 2.47~12.30 kW이다. 임계속도가 발열량의 1/4승에 비례하여 증가하였다. 터널 경사가 증가할수록 굴뚝효과로 인해 연기의 유동속도가 증가하여 임계속도가 증가하였다. In this study, reduced-scale experiments were conducted to analyze an effect of tunnel slope on critical velocity. The 1/20 scale experiments were carried out under the Froude scaling using ethanol pool fire. Square pools ranging from 2.47 to 12.30 kW were used experiments. Critical velocity varied with one-fourth power of the heat release rate. As the slope of the tunnel increases the critical velocity comes to be fast due to the increase of the chimney effect.

두부외상환자에서의 예후인자

최성혁,문준동,김수진,문철규,이성우,홍윤식 대한응급의학회 2001 대한응급의학회지 Vol.12 No.2

Background: Predicting outcome after head trauma is of great interest for clinicians, especially in the early stage. It may provide a basis for therapeutic strategies and may be helpful to select different approaches. But, reliable outcome prediction from head trauma is still unresolved. The purpose of this study is to determine which clinical parameters can be used effectively after an event of head trauma. Methods: In our study we studied head trauma patients who came to the Emergency department of Korea University Medical School Anam Hospital from the 1st of June 1998 to 31th of January 2000, looked into medical records, and studied the records in a retrospective manner. The head trauma patients were divied into two group, a) favourable outcome-related and b) unfavourable outcome-related. The two groups were then subdivided according to their sex, age, the mechanism of their injury, the time they came in, alcohol drinking, loss of consciousness, vomiting, pupil change, previous medical illness, associated injuries and were seperately compared and analyzed. And the factors affecting Glasgow Outcome Scale(GOS) were analyzed in the parameters of Injury Severity Score(ISS), Revised Trauma Score(RTS), Glasgow Coma Scale(GCS), motor score of GCS(mGCS), Marshall Computed Tomographic Classification(MCTC). Statistically, t-test and Mann-Whistney rank sum test using Jandel-sigma were used in the study and then were assessed in Chi-square analysis methods. The statistical significance was determined at a level of p less than 0.05. Results: The total of the head trauma patients, added up to 129 people, 99:males and 30:females. Among this sum, 99 patients showed a favourable outcome and 30 patients showed an unfavourable outcome at discharge. The causes of injury included: automobile accident in 42 cases; fallss in 26; assaults in 6; and accidental-slipping injury etc in 55 cases. 12 patients had bilateral unreactive pupils on admission, 2 had unilateral reactive pupils, and 113 had bilateral reactive pupils. Compared to the favourable outcome-related head trauma group, the unfavourable outcome-relared head trauma group had more history of loss of consciousness, unreactive pupils and tended to have previous medical illness. There were no difference in alcohol related, vomiting and associated injuries between two groups(favourable outcome-related head trauma group: unfavourable outcome-related head trauma group). Substantial difference were observed in GCS, mGCS, ISS, RTS, MCTC between two groups. Patients with unfavourable outcome had a significantly higher ISS, lower RTS, lower mGCS. After MCTC, patients with mass lesion had unfavourable outcome than patients with diffuse injury. Conclusion: Age, history of loss of consciousness, previous medical illness and unreactive pupil change are predictives of outcomes of head trauma patients with respect to Glasgow outcome scale. The lower GCS, lower RTS, lower mGCS, higher ISS, mass lesion based on CT scan provide poorer prognostic outcome in patients with head trauma. Use of prognostic factors thorough complete history taking and physical examination would provide useful prognostic information and facilitate improved therapeutic decision-malting in head-injuried patients.