반응표면분석법을 이용한 루테늄 알루미나 메탈모노리스 코팅촉매의 암모니아 분해 최적화

최재형,이성찬,이준혁,김경민,임동하 한국청정기술학회 2022 청정기술 Vol.28 No.3

As a result of the recent social transformation towards a hydrogen economy and carbon-neutrality, the demands for hydrogen energy have been increasing rapidly worldwide. As such, eco-friendly hydrogen production technologies that do not produce carbon dioxide (CO2) emissions are being focused on. Among them, ammonia (NH3) is an economical hydrogen carrier that can easily produce hydrogen (H2). In this study, Ru/Al2O3 catalyst coated onmetallic monolith for hydrogen production from ammonia was prepared by a dip-coating method using a catalyst slurry mixture composed of Ru/Al2O3 catalyst, inorganic binder (alumina sol) and organic binder (methyl cellulose). At the optimized 1:1:0.1 weight ratio of catalyst/inorganic binder/organic binder, the amount of catalyst coated on the metallic monolith after one cycle coating was about 61.6 g L-1. The uniform thickness (about 42 μm) and crystal structure of the catalyst coated on the metallic monolith surface were confirmed through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Also, a numerical optimization regression equation for NH3 conversion according to the independent variables of reaction temperature (400-600 °C) and gas hourly space velocity (1,000-5,000 h-1) was calculated by response surface methodology (RSM). This model indicated a determination coefficient (R2) of 0.991 and had statistically significant predictors. This regression model could contribute to the commercial process design of hydrogen production by ammonia decomposition.

Characteristics of vacuum fractional distillation from pyrolytic macroalgae (Saccharina japonica) bio-oil

최재형,김승수,우희철 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.51 No.-

Crude bio-oil from the brown alga Saccharina japonica was separated into distilled fractions underreduced pressure (40 mmHg). The three bio-oil distillates were depending on temperature (Fraction I;40 C, Fraction II; 40–120 C, Fraction III; 120–160 C, solid residue; b.p. > 160 C). The characteristic ofthe middle distillates showed that aliphatics (including alkanes) and aromatics (including heterocyclics)were mostly distributed in a dark hydrophobic oil (DHO) of Fractions II and III, while anhydrosugars,acids, ketones and ethers were mainly concentrated in a transparent hydrophilic oil (THO) of Fractions IIand III.

XML Parser를 활용한 최신 영화 정보 제공 연구

최재형,구민정 국제문화기술진흥원 2017 The Journal of the Convergence on Culture Technolo Vol.3 No.1

최근 스마트 폰 사용자가 늘어나면서 스마트 폰에 대한 여러 기능이 추가되고 있고 점점 더 발전되고 있으 며, 실제로도 실생활에 편리함을 위해 도움이 되는 많은 Application이 나오고 있다. 본 연구에서는 보고 싶은 영화 에 대한 정보를 뉴스 사이트 RSS로 XML 파서를 이용하여 영화와 관련된 뉴스기사를 호출하여 리스트로 출력하였 다. 본 안드로이드앱 서버는 Ubuntu로 구축하였으며, 구축한 게시판을 통해 최신 영화정보까지 제공하도록 하였으며, 원하는 정보를 클릭하면 상세정보를 제공하는 메뉴로 배치하였다. With the increase in the number of smart phone users, smart phones themselves are seeing progress in terms of available functions. Many applications, too, are being developed to increase convenience in daily life. This study issued a list of information on films that the user wishes to see, by using an XML parser to call news articles related to the films in question to the news site RSS. The Android App server was built using Ubuntu and the latest film information was provided through the board that was built. The menu was consisted in a manner so that when the information interested was clicked on, a more detailed set of information became available.

기본소생술 교육에서 가슴압박 기억에 음악적 리듬이 주는 효과

최재형,임훈,조영순,조규종,안정환 대한응급의학회 2011 대한응급의학회지 Vol.22 No.6

Purpose: An adequate chest compression rate during CPR is associated with improved hemodynamics and primary survival rate. The purpose of this study was to compare performance based measures of chest compression (CC),including compression rate and depth, from two versions of a CPR course: Instructor-led (IL) training, and the same IL training but augmented with rhythmic music. Methods: Ninety-one medical students having completed the BLS provider course, 4 months prior, participated in CPR quality improvement education. Participants performed 2 min of CC on a manikin utilizing an accelerometer-based system that measured both rate (CC/min) and depth (cm) of CC. CC parameters were evaluated three times: prior to the education, immediately after the education,and again after four months. CPR quality was analyzed using the manikin/accelerometer system. The primary outcome measures included: (1) compression rate, (2)compression depth, (3) percentage of compressions performed with adequate rate, (4) percentage of compressions performed with adequate depth, (5) absolute deviation from 100 in terms of compression rate, and (6) each 2 minute test was divided into 4 30 second sections, and any rate differences between the 4 sections were assessed. For the augmented IL study, popular music with a tempo of 100beats per minute was utilized. Results: There were no differences in CC rate and depth between the two IL trainings. However, students offered IL training augmented with musical rhythm performed CC with a higher percentage of adequate rate and depth. They also had less absolute deviation and variation of CC rate difference between the four, 30 second sections, than students instructed without the use of rhythmic music. Conclusion: Students receiving IL training augmented with music performed adequate, standardized CC with a steadier rate than those who received IL training without the benefit of music. This result provides evidence to support the use of rhythmic music in improving BLS education results.

병렬 기계를 사용하는 반도체 FAB 공정에서의 최적 배치 크기 결정에 관한 연구

최재형,성진모,노가연,정봉주 한국경영과학회 2010 한국경영과학회 학술대회논문집 Vol.2010 No.6

본 연구에서는 전체 반도체 생산 공정 중 병목공정으로 지적되는 FAB공정의 사이클타임을 최소로 하는 최적 배치크기를 제안한다. FAB공정은 동일한 공정을 여러 번 반복하여 방문하는 특징을 가진 re-entrant공정으로서 이로 인한 공정의 복잡성이 매우 높다. 또한 FAB공정을 구성하는 설비의 작동시간 및 설비수의 상이함 등으로 인해 FAB공정 관리에 많은 어려움이 지적되어 왔고, 이를 해결 하기 위한 FAB공정 배치 크기, 투입률, 스케쥴링과 같은 많은연구가 진행되어 왔다. 이에 본 연구에서는 배치크기를 통한 FAB공정 사이클타임 산출모델을 제안하고, 이를 통해 사이클타임을 최소로 하는 최적 배치 크기산정 방법을 제안한다. 또한 산출된 모델을 검증하기 위한 수리실험을 진행하였다.

Segmental Arterial Mediolysis으로 인한 신경색과 혈복강

최재형,조영순,김재우,이정원,문형준 대한응급의학회 2012 大韓應急醫學會誌 Vol.23 No.6

This article reports a patient with both a renal infarction and acute intra-abdominal hemorrhage secondary to a rare vascular disease, segmental arterial mediolysis. The patient was a 37-year-old male who presented with acute right flank pain. Abdominal and pelvic computerized tomography (CT) showed a right renal infarction. After three days, the right flank pain had diminished but left flank pain began. Visceral angiography revealed a wedge shape perfusion defect at the mid pole of the left kidney, suggesting a left renal infarction but there were no definite perfusion defects at the right kidney. After ten days, the patient complained of abdominal pain and 2 episodes of syncope. Abdominal CT revealed active bleeding from the splenic artery and a large amount of hemoperitoneum. After emergency embolization,the patient’s were stabilized. After 28 days, his condition was improved and discharged without complications. The angiographic and laboratory findings were consistent with a diagnosis of segmental arterial mediolysis involving the renal and splenic artery. This is the first case report of clinical progression related to segmental arterial mediolysis requiring emergent coil embolization.

소아에서 결핵에 의한 흉수와 마이코플라즈마 폐렴에 의한 흉수 감별을 위한 흉수 Adenosine Deaminase의 유용성

최재형,허원경,백혜성,오재원,이하백 대한 소아알레르기 호흡기학회 2012 Allergy Asthma & Respiratory Disease Vol.22 No.4

Purpose:Determination of adenosine deaminase (ADA) in pleural fluid has been suggested as another tool to establish early diagnosis of tuberculous pleural effusion. However, there are few studies concerning its usefulness in children. The objective of this study was to evaluate the utility of the determination of ADA level in pleural fluid for the differential diagnosis between tuberculous pleural effusion (TPE) and Mycoplasma pneumonia with pleural effusion (MP) in children. Methods:We retrospectively reviewed the clinical records of 13 TPE patients and 21 MP patients with pleural effusion. Also, we analyzed ADA levels, and clinical, biochemical, microbiologic and cytologic findings in the pleural fluid. Results:The pleural fluid of all the subjects revealed exudative rather than transudate characteristics. The mean ADA level in the TPE group was significantly higher than that in the MP group (106.27±43.71 IU/L vs. 65.28±26.27 IU/L, P=0.003). The area under the curve in receiver operating characteristic analysis was 0.810. With a cut-off level for ADA of 60 U/L, the sensitivity, specificity, positive predictive value, and negative predictive value were 92.3%, 61.9%, 60.0%, and 92.9%, respectively. As many as 38.9% of patients with MP were false-positive with this ADA cut-off setting. Conclusion:Although the measurement of ADA activity in pleural fluid can help TPE diagnosis, we should consider that some cases of MP with pleural effusion showed high ADA activities. Accordingly, the utility of the ADA level in pleural fluid for the differentiation of TPE from MP declines and additional relevant studies are required. 목 적:흉막 액에서 adenosine deaminase (ADA) 활성도 측정은 결핵성 흉수의 진단에 유용한 검사로 제시되어왔다. 하지만 소아에서 ADA의 유용성에 대한 연구는 많지 않은 실정이다. 본 연구는 소아 부폐렴성 흉수에서 결핵성 흉수와 Mycoplasma pneumoniae 폐렴에 의한 흉수의 감별 진단을 위한 ADA 측정의 유용성을 알아보기 위해 본 연구를 시행하였다. 방 법:결핵성 흉수 환자 13례, 흉수를 동반한 M. pneumoniae 폐렴 환자 21례를 대상으로 임상 소견, 흉수의 생화학적, 미생물학적 및 혈액학적 검사, ADA치 등을 후향적으로 비교 분석하였다. 결 과:결핵성 흉수 환자 군의 ADA는 흉수를 동반한 M. pneumoniae 폐렴 환자 군의 ADA에 비해 통계적으로 유의하게 증가되어 있었다(106.27±43.71 IU/L vs. 65.28± 26.27 IU/L; P=0.003). 이들 측정값에 대한 receiver operating characteristic (ROC) 곡선 분석을 시행하였고 흉수 ADA 60 IU/L 이상일 때, 민감도, 특이도, 양성 예측도, 음성 예측도는 각각 92.3%, 61.9 %, 60.0%와 92.9%였다(ROC 곡선하 면적, 0.810; P=0.003). 흉수를 동반한 M. pneumoniae 폐렴 환자 군에서 ADA 60 IU/L 이상인 환자는 8명(38.1%)이었다. 결 론:흉수 내 ADA 증가는 결핵성 흉수의 진단에 도움이 될 수 있지만, 흉수를 동반한 마이코프라즈마 폐렴 환자에서도 ADA가 증가할 수 있으므로 두 질환을 감별하는데 유용성이 떨어진다 따라서 합당한 추가적인 검사가 더 필요하다.

경부 추간관절차단 후 발생한 경추 경막외 혈종

최재형,조영순,김호중 대한응급의학회 2013 대한응급의학회지 Vol.24 No.4

Facet joint nerve blocks is the most commonly utilized interventions in managing chronic spinal pain. A fluoroscopically directed facet joint nerve block for pain management may result in a rare complication of spinal epidural hematoma causing acute myelopathy. Although this complication is well-known with epidural anesthesia (where it is usually seen with impaired hemostasis), there are surprisingly few case reports of epidural hematoma after a facet joint nerve block. We report here a case of a 58-year-old man, with no evidence of coagulopathy and not taking antiplatelet medication,having a sudden onset of acute cervical myelopathy from a large cervical epidural hematoma one hour after a facet joint nerve block. Following prompt surgical evacuation of the clot, the patient made a nearly complete recovery. Spinal epidural hematoma after spinal puncture is usually associated with impaired hemostasis. However, this case illustrates that it may occur in the absence of known risk factors. The delayed onset and the absence of risk factors have implications for the use of this procedure in chronic pain management.

1P-310 팔라듐 촉매계를 이용한 다시마 유래 바이오-오일의 수소첨가 탈산소화 반응연구

최재형,서동진,김승수,허광선,우희철 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.0

전도냉각형 고온초전도 SMES의 냉동기와 마그네트 간의 절연 특성

최재형,곽동순,천현권,김해종,성기철,김상현 한국초전도저온학회 (구 한국초전도저온공학회) 2006 한국초전도저온공학회논문지 Vol.8 No.3