2 kW급 브레이튼 냉동기용 열역학 사이클 및 극저온 터보 팽창기 설계

이진우,이창형,양형석,김석호,Lee, Jinwoo,Lee, Changhyeong,Yang, Hyeongseok,Kim, Seokho 한국전력공사 2016 KEPCO Journal on electric power and energy Vol.2 No.2

초전도 전력 케이블의 상용화 노력에 따라 점차 장선화 되면서, 단위 냉각 시스템당 냉각용량이 큰 대용량 냉동기의 필요성이 증가하고 있다. 국내에서는 극저온 냉동기에 대한 기술 부족으로 인해 현재 극저온 냉동기는 해외 선진사로부터 고가의 비용으로 수입되고 있다. 초전도 전력 케이블의 상용화를 위해서는 대용량 브레이튼 냉동기의 국내 개발이 시급하다. 대용량 브레이튼 냉동기의 구성은 복열식 열교환기, 압축기, 극저온 터보 팽창기로 구성되어 있으며, 냉동기 효율과 가장 직접적인 연관이 있는 것은 극저온 터보 팽창기이다. 극저온 터보 팽창기는 극저온에서 고속으로 회전하면서 고압의 헬륨 혹은 네온 가스를 팽창시켜 온도를 낮추는 역할을 한다. 본 논문에서는 역브레이튼 냉동 사이클을 설계하고, 이에 적합한 극저온 터보 팽창기를 설계하였다. The High Temperature Superconducting power cables (HTS power cables) become increasingly longer to commercialize the HTS power cable system. Accordingly, demands on refrigerators of large cooling capacity per a unit system have been increased. In Korea, it is currently imported from abroad with the high price due to insufficient domestic technologies. In order to commercialize the HTS power cables, it is necessary to develop the refrigerators with large cooling capacity. The Brayton refrigerators are composed of recuperative heat exchangers, compressors and cryogenic turbo expanders. The most directly considering the efficiency of the Brayton refrigerator, it depends on performance of the cryogenic turbo expander. Rotating at high speed in cryogenic temperature, the cryogenic turbo expanders lower temperature by expanding high pressure of a helium or neon gas. In this paper, the reverse Brayton cycle is designed and the cryogenic turbo expander is designed in accordance with the thermodynamic cycle.

지역거점 공공병원의 환경적 요인에 따른 생산성 분석

이진우,Lee, Jinwoo 한국병원경영학회 2017 병원경영학회지 Vol.22 No.3

The purpose of this study is to analyze the difference of productivity according to environmental factors among 25 Regional base public hospitals. Also this study is to propose a method to improve the productivity of Regional base public hospitals in the future by improving the public performance and stable management performance by studying the productivity variables affecting profitability. The survey period was based on the last three years, and 25 Regional base public hospitals were selected for the survey. The dependent variable is the total capital medical marginal profitability and the medical profit marginal profitability which are the indicators of profitability. The independent variable, productivity, is classified into three indicators: capital productivity, labor productivity, and value added productivity. The ANOVA analysis method was used to analyze the productivity difference according to the frequency factor and the environmental factors of the Regional base public hospitals. Finally, we conducted a hierarchical regression analysis to examine the productivity variables affecting profitability. The results of this study showed that there were differences in productivity due to environmental factors such as hospital size, competition in the local medical market, and differences in management performance. The difference in productivity and profitability depending on the environmental factors suggests that it is difficult for Regional base public hospitals in each regional base to perform a balanced public service. In order to overcome this, it is necessary to provide balanced medical services such as government financial support expansion, regional medical demand forecasting and facility infrastructure construction.

무인 지상 차량 네트워크에서 GPS 재밍에 강인한 위치기반 라우팅

이진우,정우성,김용주,고영배,함재현,최증원,Lee, Jinwoo,Jung, Woo-Sung,Kim, Yong-joo,Ko, Young-Bae,Ham, Jae-Hyun,Choi, Jeung-Won 한국군사과학기술학회 2015 한국군사과학기술학회지 Vol.18 No.4

UGVs(Unmanned Ground Vehicles) are robots that can substitute humans in reconnaissance operations of potentially dangerous and contaminated sites. Currently, there have been active research on utilizing UGVs in military environments. Much resrach has been focused on exploiting the weakness of topology-based routing and instead utilize location-based routing for the networking of UGVs. It is generally assumed that location-based routing methods can fully utilize the location information gained from GPS. However, this may not be possible in tactical environments due to enemy GPS jamming and LOS(Line of Sight) limitations. To solve this problem, we propose a location-based routing scheme utilizing low control message that can calibrate the location information using GPS information as well as location of neighboring UGV, movement direct and speed information. Also utilizing topology-based routing scheme to solve incorrect location information in GPS jamming region.

인가전압에 따른 피에조 인젝터의 분무 특성

이진우(Jinwoo Lee),배충식(Choongsik Bae) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Piezo actuated injector is known to produce less NOx and PM in comparison with solenoid actuated injector. And it is because piezo actuated injector can be operated with higher injection pressure up to 2000 bar and multiple injection up to 7 times, which are enabled by its greater operating force and faster response time. Needle opening and closing of piezo actuated injector is determined by the movement of piezo stack directly, which is proportional to induced voltage. In this study, spray characteristics of piezo actuated injector with various induced voltage have been investigated by measuring injection rate and macroscopic images. Results showed that the rising slope of injection rate is steeper, spray tip penetration is greater and spray angle is larger with higher induced voltage.

Artificial Neural Network Based Failure Diagnosis of Temperature Sensor Embedded in Hot Plate

Jinwoo Lee(이진우),Daeil Kwon(권대일),Yoonki Sa(사윤기) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12

수소충전소 디지털 전환을 통한 설비 건전성 관리 및 안전성 사전진단 방법

이진우(Jinwoo Lee),최진혁(Jinhyuk Choi),신상봉(Sangbong Shin),한종일(Jongil Han) 한국가스학회 2022 한국가스학회 학술대회논문집 Vol.2022 No.11

직접분사식 디젤엔진에서 디젤과 JP-8의 성능비교

이진우(Jinwoo Lee),박정서(Jungseo Park),배충식(Choongsik Bae) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2007 No.11

차기 TMMR을 위한 개선된 무선랜 QoS 기법

이진우(Jinwoo Lee),이홍로(Hongro Lee),고영배(Young-Bae Ko) 한국통신학회 2014 한국통신학회 학술대회논문집 Vol.2014 No.1

기후부정의(不正義)의 구조와 개선방안 : 국내 국회 법제 논의를 중심으로

이진우 ( Lee Jinwoo ) 서울대학교 공익인권법센터 2022 공익과 인권 Vol.22 No.-

기후위기가 가속화되면서 기후위기의 원인과 결과에 있어 사회적 불평등도 심화되는 양상을 보이고 있다. 특히 결과적 불평등을 넘어 절차적 불평등까지 나타나며, 기후위기를 ‘정의’의 관점에서 이해하고 해결하기 위한 노력이 나타났다. 1992년 체결된 유엔기후변화협약에서 ‘공동의 차별화된 책임’을 명시한 이후 2015년 ‘기후정의’ 원칙을 수용한 파리협정까지 불평등을 해소하기 위한 국제적 노력은 단계적으로 구체화됐다. 우리나라 역시 파리협정 체결 이후 관련 법ㆍ제도를 강화하며 본격적으로 기후정의에 접근하기 시작했다. 2020~2021년에 발의된 기후위기 관련 대응법안들은 모두 ‘기후정의’와 ‘정의로운 전환’ 개념을 포함하고 있다. 그러나 상당수의 법률안이 기본법적 위상으로 인해 개념을 정의하는 조항만 포함하고 있어 구속력 있는 후속체계를 만들어야 한다. 본 논문에서는 국내 기후 관련 법ㆍ제도에 포함되어야 할 기후정의의 원칙을 검토하고 제안한다. 또한 기후부정의에 대응할 수 있는 입법 보완 방향과 개선방안을 분석한다. 이를 통해 온실가스 총량을 감축하는 자연과학적 대응과 더불어 대상 간 불평등을 저감하는 사회과학적 대응방식을 연계하여 대응의 효과성을 높이고자 한다. With the acceleration of the climate crisis, the problem of social inequality also rises as the cause and result of the climate crisis. In particular, procedural inequality appeared beyond consequential inequality, and efforts to understand and solve the climate crisis from the perspective of “justice” were made. International efforts to address inequality have been phased out from the 1992 United Nations Framework Convention on Climate Change, which stated the concept of “Common but Differentiated responsibilities (CBDR)”, to the Paris Agreement in 2015, which accepted the principle of “climate justice”. The Republic of Korea also began to approach climate justice in earnest by strengthening related laws and systems after the signing of the Paris Agreement. All of the climate crisis-related countermeasures proposed in 2020-2021 include the concepts of “climate justice” and “just transition”. However, a binding follow-up system should be created, as a significant number of legislation bills contain provisions that only define concepts due to their fundamental legal status. This paper reviews and proposes the principles of climate justice that must be included in domestic climate-related laws and systems. It also analyzes the direction of supplementary legislation and improvement measures that can respond to climate injustice. Through this, it proposes the method to increase the overall effectiveness of the response by linking the natural science response to reduce the total amount of greenhouse gas to the social science response method to reduce inequality between targets.

대형 디젤 엔진에서 연소 가시화를 통한 항공유와 디젤의 배기 특성 분석

이진우(Jinwoo Lee),배충식(Choongsik Bae) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

Combustion process with JP-8 and diesel was analyzed in an optically-accessible single-cylinder heavy-duty diesel engine equipped with a high pressure common-rail injection system. Direct imaging and two-color thermometry were applied to verify the emission trend for both fuels. The combustion process was characterized by means of image analysis focusing on the luminosity. The results from the two-color thermometry were analyzed by flame temperature and KL factor distribution. From the combustion process analysis of direct imaging, it was verified that JP-8 had a longer ignition delay compared to diesel, while flame was vanished more rapidly. Analysis of flame luminosity intensity showed that diesel combustion had higher intensity and lasted for longer duration. Two-color thermometry results showed that higher temperature region was distributed more with JP-8 combustion, which means that more NOx was formed with JP-8 combustion. Also, relatively homogeneous and low level of KL factor distribution was shown with JP-8 combustion, which implied that JP-8 combustion produced less smoke emission.