방사선조사에 의한 한국산어류의 품질보존에 관한 연구 : Ⅰ. 민어 , 참조기 및 물가자미의 감마선 조사 후의 보존특성 Ⅰ. Radurization of croaker , yellow corvenia and roundnose flounder

이민철,정종락,김수일 한국수산학회 1976 한국수산과학회지 Vol.9 No.2

민어 (croaker-Nibea imbricata, Matsubara), 참조기 (yellow corvenia-Pseudosciaena manchurica, Jordan and Thompson) 그리고 물가자미(roundnose flounder-Xystrias grigorjewi, Herzenstein) 어육을 0.5 Mrad이하의 감마선량에 조사하여 냉장기간중의 선도 유지기간 연장을 가져오는 최적 조사선량을 구하였다. 조사된 어육을 0˚와 5℃에 35일간 저장하는 동안에 일어나는 관능학적 변화를 미생물학적, 화학적 변화와 비교 검토하였다. 0℃ 저장을 위한 민어와 참조기의 최적선량은 0.1 Mrad였으며 5℃ 저장에서는 0.2 Mrad였다. 물가자미는 방사선 조사에 대단히 민감하여 0˚와 5℃ 다같이 0.1 Mrad였다. 각각의 최적선량에 조사 처리하므로써 민어의 경우 0℃에서는 선도 유지기간이 비 조사구의 2주간에서 5주간(3-4배)으로 연장되었으며 5℃에서는 역시 1주간 이내에서 4주간(4-5배)으로 연장이 가능하였다. 참조기는 0℃에서는 3∼4배로, 5℃에서는 4-5배로 그리고 물가자미는 0℃에서 4-5배, 5℃에서 6-7배로 각각 연장되었다. Optimum doses The optimum dose that may be defined as the dose below the maximum permissible dose, yet would bring about a significant storage life extension at refrigerated temperatures, varied with species of fish as well as with the postirradiation storage temperatures. Thus the dose of 0.1 Mrad was considered to be optimum for the croaker and yellow corvenia at 0℃, while at 5℃ the dose of 0.2 Mrad would be suitable for both species. The roundnose flounder was more radiosensitive and even at the dose of 0.1 Mrad a slight irradiation odor was detected immediately after the radiation treatment. Such degree of irradiation odor disappeared upon stoage, therefore, the dose of 0.1 Mrad was considered to be optimum for the roundnose flounder at both 0˚and 5℃. Storage life extension The croaker meats irradiated at 0.1 Mrad could be held at 0℃ as long as 5 weeks in good acceptable conditions, while the unirradiated control became unacceptable within 2 weeks-3-4 for extension of storage life at 0℃. At the storage temperature of 5℃, the storage life of 0.2 Mrad irradiated samples was extended from less than one week to 4 weeks-4-5 fold extension. The storage life extension of 0.1 Mrad irradiated yellow corvenia at 0℃ was from less than 2 weeks for the unirradiated to 4 weeks-approximately 2-3 folds and that of 0.2 Mrad irradiated samples stored at 5℃ was from 5 days to 3 weeks 4-5 folds. The roundnose flounder meats irradiated at 0.1 Mrad could be held at 0℃ for 3-4 weeks as compared to less than 1 week for the unirradiated and at 5℃ the storage life could be extended from less than 3 days to up to 2 weeks. Thus the storage life extension by 4-5 folds and by 6-7 folds was possible at 0˚and 5℃ storage, respectively. Postirradiation storage microbiology and biochemistry In general 10 fold reduction of initial microflora was realized as a result of irradiating fish samples at 0.1 Mrad. The extent of microflora reduction increased with increasing doses applied, but not proportionately dependent. The microbial growth in the irradiated was severely retarded during the subsequent storage period, lagging far behind that of the unirradiated control samples except in the late storage phase, when the levels of microflora of the irradiated either approached to or rose above the levels of the unirradiated. The microbiological changes caused by irradiation was reflected in the pronounced suppression of TVB and TMA accumulation during the storage period. This suggests that irradiation treatment brought about both quantitative and qualitative changes in microflora initially present and it is reasonable to suggest that the microflora removed by irradiation in fact represent most of the flora capable of producing TVB and TMA in normal fish spoilage process.

국방규격 개선사업의 만족도에 영향을 미치는 결정요인 분석 : 기술변경 개선항목을 중심으로

이민철,김영현,안영준 국방기술품질원 2023 국방품질연구논집 Vol.5 No.1

The purpose of this study is to analyze the factors that affect satisfaction with defense standard improvement projects and to derive key policy implications. To analyze the factors, we surveyed 62 stakeholders from configuration control management agencies and military supply manufacturers to investigate overall satisfaction with technical change improvement items and defense standard improvement projects. The analysis methods used were frequency and cross-analysis, t-test and F-test, and multiple regression analysis. Consequently, we found that satisfaction with productivity improvement and resolution of quality assurance obstacles are the major decision factors affecting satisfaction with defense standard improvement projects. In conclusion, we described the significance and limitations of the research results, and future research directions.

음료산업

이민철 한국식품과학회 1988 식품과학과 산업 Vol.21 No.3

국방규격 개선사업의 성과평가모형 개발 및 적용방안 연구

이민철,김영현,안영준,김준수 한국품질경영학회 2023 품질경영학회지 Vol.51 No.2

Purpose: The purpose of this study is to identify key performance evaluation items and factors that are effective and practical for project management of defense standard standard improvement projects, and to develop a quantitative performance evaluation model. Methods: For the development of a performance evaluation model for defense standard improvement projects, we analyzed past major project performance and derived evaluation items and factors. To increase the objectivity and efficiency of project evaluation, we developed an evaluation index that enables relative evaluation of evaluation targets, and calculated the main importance of evaluation items using the Analytic Hierarchy Process (AHP) method based on the main opinions of expert groups. Results: The study resulted in the identification of main performance items for defense standard improvement projects, which were classified into defense standard conformity review performance and defense standard improvement performance items. We also simplified the evaluation model by integrating various evaluation items into similar evaluation factors. Additionally, we developed a quantitative evaluation index that enables relative evaluation of the targets and verified the objectivity and validity of the suggested performance evaluation model by reevaluating it using performance data from past commissioned professional institutions Conclusion: Developing a quantitative evaluation model for defense standard improvement projects is expected to provide a means of measuring the effectiveness of the project, and to be used as a tool to determine the appropriateness and effectiveness of medium and long-term project plans.

국방분야 상용품 조달 확대를 위한 발전방안에 관한 연구

이민철,박일광,서동수,권나연 대한산업공학회 2013 대한산업공학회 추계학술대회논문집 Vol.2013 No.11

IGCC 가스터빈 시스템에서 연료측 희석제가 연소성능에 미치는 영향에 대한 실험적 연구

이민철,서석빈,김미영,김시문,마삼선,주용진 한국에너지공학회 2009 한국에너지공학회 학술발표회 Vol.2009 No.9

Effects of Majorana bound states on dissipation and charging in a quantum resistor-capacitor circuit

이민철 한국물리학회 2019 Current Applied Physics Vol.19 No.3

We investigate the effects of Majorana bound states on the ac response of a quantum resistor-capacitor circuit which is composed of a topological superconducting wire whose two ends are tunnel-coupled to a lead and a spinless quantum dot, respectively. The Majorana states formed at the two ends of the wire are found to suppress completely or enhance greatly the dissipation, depending on the strength of the overlap between two Majorana modes and/or the dot level. We compare the relaxation resistance and the quantum capacitance of the system with those of non-Majorana counterparts to find that the effects of the Majorana state on the ac response are genuine and cannot be reproduced in ordinary fermionic systems.

가방 착용 방법에 따른 보행 시 다리관절 각도, 콥스 각, 족압 비율의 변화

이민철,이수현,장상훈,Lee, Jonathan,Lee, Su-Hyun,Jang, Sang-Hun 대한물리치료과학회 2018 대한물리치료과학회지 Vol.25 No.2

Purpose: This study was conducted to analyze the effect of bag type on gait kinematic factors. The purpose of this study was to compare the Cobb's angle, leg angle and foot pressure difference according to bag type among 20 university students. Methods: The bag type was applied with two kinds of bags: not wearing a bag, backpack, and an eco bag. The bag weight was 10% of subjects weight in during experiment and only bag weight was 0.5kg. Results: Knee joint angle is increased when wearing backpack or an eco bag than not wearing bag. Cobb's angle increased when wearing backpack and wearing eco back. The difference in right and left foot pressure increased when wearing eco bag than not wearing bag and wearing backpack. Conclusion: Therefore, wearing a heavy backpack or an eco bag when walking for a long time may cause scoliosis and change the walking form.

레이다처리장치 시험장비의 데이터 처리방안

이민철,김용민 한국군사과학기술학회 2018 한국군사과학기술학회지 Vol.21 No.6

To develop and check a Radar Processor Unit, checking the function and performance of the requirement is very important factor in developing Radar. General methods for verifying the Radar is simulation test, environment linkage test and field operation test, firstly, in case of requirement analysis phase, verify Radar algorithm and design by using mathematical method based simulation test method, and secondly, in case of unit test and integrated test phase, Test Equipment is set to simulate radar environment in the lab to verify radar function and performance. Lastly, field operation test phase is carried out to confirm the function and performance after it is mounted on the actual equipment. To successfully develop Radar Processor Unit, using the method of field operation test method after sufficient test cases are tested in radar environmental interlocking method in order to save cost and testing period and because of this reason, development of the Radar Processor Unit Test Equipment is becoming very important factor. In this paper, we introduce the concept of test equipment development and important factors in test equipment, which are target simulation, data processing and device interlocking.

시간지연분석을 이용한 모델 가스터빈 연소기 내에서 H₂/CO/CH₄ 합성가스의 연소불안정 메커니즘에 관한 실험적 연구

이민철,윤지수,주성필,김정진,윤영빈 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11

본 연구는 GE7EA 모델 가스터빈 연소기 내에서 H₂/CO/CH₄로 구성된 합성가스의 연소불안정 메커니즘에 대해 기술하고 있다. 상세한 불안정 메커니즘은 대류, 음향, 화학시간과 같은 특성시간스케일을 이용하여 그들의 지연시간을 계산한 후 불안정 주기가 Rayleigh 기준에 일치하는지 여부에 의해 판단하는 시간지연모델을 이용하여 분석되었다. 화염에서 대류 및 음향 시간스케일을 계산하기 위해서는 OH-PLIF 이미지와 화염 평균온도를 이용한 음향속도가 사용되었다. 수소함량을 증가시킬수록, 화염의 길이는 줄어들었고, 따라서 화염안에서 대류속도가 주로 줄어들어 연소불안정의 크기와 주파수에 영향을 미쳤다. 예를 들어, 고부하 고수소함량의 조건에서는 수소의 빠른 연소속도로 인해 짧은 파장의 동압과 열발생이 결합하기 쉽고, 이에 고주파수의 연소불안정(1000Hz 이상)이 발생하였다. 그 반면에 저부하 저수소함량의 조건에서는 긴 파장의 동압과 열발생이 결합하기 쉽고, 이에 저주파수의 불안정(800Hz 이하)이 발생되었다. This Study describes the combustion instability mechanism of synthetic gas composed mainly of H₂/CO/CH₄ model GE7EA gas turbine combustor. Detailed instability mechanism is analyzed using time lag model which judges whether the time difference between periodic time with sum of lagging time scales such as convective, acoustic, chemical and effective times, coincides with the Rayleigh criterion. To calculate the convective and acoustic time scale in flame, time averaged OH-PLIF images and speed of sound using mean temperature in flame are considered. As increasing hydrogen content, flame is shortened and thus mainly convective time in flame is decreased. For example, in high load and high hydrogen condition, high frequency of instability(over 1000Hz) is generated since dynamic pressure and heat release in flame is easier to be coupled with shorter wave length due to fast burning of hydrogen. On the other hands, in low load and small hydrogen condition, low frequency of instability(under 800Hz) is generated since pressure and heat release in flame is easier to be coupled with longer wave length.