Mo 함유 오스테나이트계 스테인리스강의 공식특성에 미치는 이온질화의 영향

조용석,최한철,김관휴 ( Yong Seok Cho,Han Cheol Choe,Kwan Hyu Kim ) 한국부식방식학회 1994 Corrosion Science and Technology Vol.23 No.1

백서 두개골에서 이종골 이식 후 치유에 관한 실험적 연구

조용석,김경원,Cho, Yong-Seok,Kim, Kyoung-Won 대한악안면성형재건외과학회 1999 Maxillofacial Plastic Reconstructive Surgery Vol.21 No.1

The purpose of this investigation was to evaluate the acceptability of the collagen-based xenograft ($Laddec^{(R)}$). Full thickness bone defects were prepared in the calvaria of the rats. In the experimental groups the bone defects were filled with a kind of collagen based xenograft. And bone defects, which left without filling, were used as control groups. Sequential sacrifice was performed at the 1st, 2nd, 4th, 8th, and 16th weeks of experiment. 1. At the 1st week of experiment, infiltration of chronic inflammatory cell was observed in all groups. In the experimental group, resorption of the xenograft was initiated. 2. At the 2nd week of experiment, infiltration of chronic inflammatory cells was decreased in all groups. In the experimental group, active resorption of xenograft and new bone formation from the periphery of the xenograft was observed. 3. At the 4th and 8th weeks of experiment, more resorption of the xenograft and new bone formation with calcification was observed in the experimental group. 4. At the 16th week of experiment, small bone trabecula was formed partially in the control group but that couldn't fill the whole bone defect. In the experimental group, more advanced resorption of xenograft and more new bone formation was observed. However mid portion of the xenograft was still remained without resorption. 5. From this experiment, we concluded that the collagen-based xenograft had some osteoconductive but no osteoinductive property. So the xenograft would be used for the bone defect filling material where rapid bone remodeling is not required.

저장신뢰도 유지를 위한 최적 2단계 주기적 검사정책

조용석,이주호,Cho, Yong-Suk,Lee, Joo-Ho 한국통계학회 2008 Communications for statistical applications and me Vol.15 No.3

본 연구에서는 장기간 보관 중인 장비의 신뢰도를 유지하기 위한 2단계 주기적 검사모형을 제안하였다. 제안된 모형은 불완전한 간이검사와 완전한 정밀검사를 단계적으로 사용하여 고장이 발견되거나 검사 후 저장신뢰도가 미리 정해진 값 이하로 떨어질 때 장비에 대한 오버홀을 수행한다. 제안된 모형을 사용하여 오버홀까지의 단위시간당 기대비용을 유도하고 이를 최소화하기 위한 절차를 구하였으며, 고장시간이 지수분포 및 와이블분포를 따를 경우 제안된 모형을 1단계 주기적 검사모형과 비용함수의 다양한 모수값에 대하여 비교하였다. 또한 실제 운용 중인 유도탄 시스템에 제안된 검사정책을 적용하여 현재 사용 중인 검사정책과의 비교를 수행하였다. In this thesis we propose a two-stage periodic inspection model for maintaining the reliability of a system in long-term storage. There are two types of tests available; a fallible test and an error-free test. The system is overhauled at detection of failure or when the storage reliability after inspection becomes less than or equal to the prespecified value. The expected cost per unit time until overhaul is derived and a procedure for minimizing the expected cost is suggested. The two-stage periodic inspection model is compared with the one-stage periodic inspection model for various parameters of the cost function when the failure time follows exponential and Weibull distributions. The proposed model is then applied to an existing missile system for comparison with the current inspection policy.

갑상설관낭종 및 동의 임상적 고찰

조용석(Yong Suk Cho),박성길(Sung Gil Park),전성은(Seong Eun Chon),윤대근(Dae Kun Yoon),정봉화(Bong Wha Chung),허준(Jun Hur),조마해(Ma Hae Cho),조지웅(Ji Woong Cho),박윤규(Yoon Kyu Park),채승완(Seoung Wan Chae),조성진(Seong Jin Cho) 대한외과학회 2003 Annals of Surgical Treatment and Research(ASRT) Vol.64 No.3

가솔린 기관의 냉간시동 조건에서 합성가스 배기분사 기술에 의한 촉매의 활성화 온도 도달시간 단축 및 유해배출물 저감에 관한 연구

조용석(Yong-Seok Cho),이성욱(Seang-Wock Lee),원상연(Sang-Yeon Won),송춘섭(Chun-Sub Song),박영준(Young-Joon Park) 한국자동차공학회 2008 한국 자동차공학회논문집 Vol.16 No.3

Since regulations of exhaust emissions are continuously reinforced, studies to reduce harmful emissions during the cold start period of SI engines have been carried out very extensively worldwide. During the cold start period, raising the temperature of cold exhaust gas is a key strategy to minimize the light-off time of three way catalysts. In this study, a synthetic gas containing a large amount of hydrogen was injected into the exhaust manifold to raise the exhaust gas temperature and to reduce harmful emissions. The authors tried to evaluate changes in exhaust gas temperature and harmful emissions through controlling the engine operating parameters such as ignition timings and lambda values. Also the authors investigated both combustion stability and reduction of harmful emissions. Experimental results showed that combustion of the synthetic gas in the exhaust manifold is a very effective way for solving the problems of harmful emissions and light-off time. The results also showed that the strategy of retarded ignition timings and increased air/fuel ratios with ESGI is effective in raising exhaust gas temperature and reducing harmful emissions. Futhermore, the results showed that engine operating parameters ought to be controlled to lambda = 1.2 and ignition timing = 0 ~ 3° conditions to reduce harmful emissions effectively under stable combustion conditions.

정적연소기를 이용한 합성가스의 가연한계 및 연소특성에 관한 실험적 연구

조용석(Yong-Seok Cho),이성욱(Seang-Wock Lee),원상연(Sang-Yeon Won),박영준(Young-Joon Park),김득상(Duk-Sang Kim) 한국자동차공학회 2008 한국 자동차공학회논문집 Vol.16 No.1

Synthetic gas is defined as reformed gas from hydrocarbon-based fuel and the major chemical species of the synthetic gas are H₂, CO and N₂. Among them, hydrogen from synthetic gas is very useful species in chemical process such as combustion. It is a main reason that many studies have been performed to develop an effective reforming device. Furthermore, other technologies have been studied for synthetic gas application, such as the ESGI(Exhaust Synthetic Gas Injection) technology. ESGI injects and burns synthetic gas in the exhaust pipe so that heat from hydrogen combustion helps fast warmup of the close-coupled catalyst and reduction of harmful emissions. However, it is very hard to understand combustion characteristic of hydrogen under low oxygen environment and complicated variation in chemical species in exhaust gas. This study focuses on the characteristics of hydrogen combustion under ESGI operating conditions using a CVC(Constant Volume Chamber). Measurements of pressure variation and flame speed have been performed for various oxygen and hydrogen concentrations. Results have been analyzed to understand ignition and combustion characteristics of hydrogen under lower oxygen conditions. The CVC experiments showed that under lower oxygen concentration, amount of active chemicals in the combustion chamber was a crucial factor to influence hydrogen combustion as well as hydrogen/oxygen ratio. It is also found that increase in volume fraction of oxygen is effective for the fast and stable burning of hydrogen by virtue of increase in flame speed.

연료전지 자동차의 주행성능 예측을 위한 전기자동차 및 연료전지의 성능실험과 수학적 모델링

조용석(Yong-Seok Cho),김득상(Duk-Sang Kim),안석종(Seok-jong An) 한국자동차공학회 2006 한국 자동차공학회논문집 Vol.14 No.5

In new generation vehicle technologies, a fuel cell vehicle becomes more important, by virtue of their emission merits. In addition, a fuel cell is considered as a major source to generate the electricity for vehicles in near future. This paper focuses on modeling of not only an electric vehicle and but also a fuel cell vehicle to estimate performances. And an EV cart is manufactured to verify the modeling. Speed, voltage, and current of the vehicle and modeling are compared to estimate them at acceleration test and driving mode test. The estimations are also compared with the data of the Ballard Nexa fuel cell stack. In order to investigate a fuel cell based vehicle, motor and fuel cell models are integrated in a electric vehicle model. The characteristics of individual components are also integrated. Calculated fuel cell equations show good agreements with test results. In the fuel cell vehicle simulation, maximum speed and hydrogen fuel consumption are estimated. Even though there is no experimental data from vehicle tests, the vehicle simulation showed physically-acceptable vehicle characteristics.

배기가스의 온도 및 HC와 O₂의 조성 변화에 따른 DOC­CDPF의 재생 특성에 관한 실험적 연구

조용석(Yong-Seok Cho),이성욱(Seang-Wock Lee),이정섭(Jung-Sub Lee),윤여빈(Yu-Bin Yoon),박영준(Young-Joon Park) 한국자동차공학회 2009 한국 자동차공학회논문집 Vol.17 No.1

A catalyzed diesel particulate filter (CDPF) causes the progressive increase in back pressure of an exhaust system due to the loading of soot particles. To minimize pressure drop which is generated by CDPF, the filter should be regenerated when it collects a certain quantity of soot. It is important to know characteristics of regeneration of CDPF with various of exhaust gas temperatures and compositions. The oxidation of HC in DOC leads to increase gas temperature of DOC downstream. The increased gas temperature by DOC has an positive effect on CDPF regeneration. This study presents characteristics of regeneration of CDPF with DOC according to various gas composition, such as HC and O₂ concentration. The test­rig is used to control each gas composition and temperature during regeneration of CDPF. Experimental results indicate that the increased concentration of O₂ regenerates DPF more actively. With increasing HC concentration, the gas temperature of CDPF upstream increased due to more oxidation of HC. But excessive supply of HC leads to decrease of O₂ concentration in the CDPF, which makes it hard to regenerate CDPF.

루터와 오스만 투르크

조용석(Yong-Seuck Cho) 장로회신학대학교 기독교사상과 문화연구원 2017 장신논단 Vol.49 No.4

본 연구는 16세기 종교개혁시기 오스만 투르크의 유럽침공과 관련된 루터의 신학적 대응을 탐구하고자 한다. 루터는 오스만 투르크의 군사적 위협을 독일민족 혹은 타락한 로마-가톨릭 교회를 위한 하나님의 징계라고 해석한다. 루터는 그의 문건 “투르크 전쟁에 대하여”에서 투르크 보다 적그리스도로서 묘사되는 교황에 대해 좀 더 비판적인 입장을 피력하고 있다. 그러나 이는 세속정부가 외부의 공격을 방어하지 않아도 된다는 사실을 의미하지 않는다. 이와 같은 신학적 신념에 근거하여, 루터는 그리스도인들에게 회개와 기도를 통하여 오스만 투르크에 대항해야 한다고 영적인 차원에서 권면한다. 여기서 회개는 오스만 투르크와의 영적인 전쟁의 수행을 위한 출발점이 된다. 요약하자면, 루터는 소위 그의 두 왕국론에 근거하여 영적 정부와 세속 정부의 통치영역을 구분했다. 즉 황제는 전쟁과 같은 세속적인 사안을 다루어야 하며, 성직자는 그리스도인들에게 경건한 행위를 통하여 싸워야 한다고 주장했던 것이다. 1529년 오스만 투르크가 비엔나를 침공했을 때, 루터는 오스만 투르크의 군사적 위협을 종말론적 전망 속에서 고찰했다. 그는 묵시적 종말론의 전망 속에서 오스만 투르크의 침공이 다니엘서 7장에 이미 예언되었다고 확신했다. 그는 성서에 근거하여 오스만 투르크가 결코 유럽의 기독교를 파멸시킬 수 없을 것이라고 생각했다. 더 나아가 그는 (이슬람 교도들을 위한) 올바른 기독교 변증을 위하여 코란을 연구함으로써, 이슬람 종교를 객관적으로 파악할 수 있는 기회를 확보했다. 이를 통하여 그는 독일 그리스도인들이 신앙을 강화할 수 있으며, 기독교의 진리의 명백한 증거를 제시할 수 있을 것이라고 확신했다. This study aims to investigate Luther’s theological reaction to the Ottoman invasion of Europe at the time of the Protestant reformation. Luther made it clear that sinful Germans or the corrupt Roman Catholic church had earned God’s punishment and that the Turks could be a divine means to carry it out, even if the Turks were demonic pawns. In On War against the Turk, Luther is actually less critical of the Turks than he is of the Pope, whom he calls an anti-Christ. However, this did not mean that the earthly authority should not defend their land from an aggressive attack and had the obligation to do so. From this conviction, Luther gave spiritual counsel to European Christians, providing the exhortation that they must fight against the Turk with repentance and prayer. Repentance must be the starting point. To sum up, Luther explained that the spiritual and earthly authorities act for their divinely-ordained purpose on the basis of the so-called Luther’s two kingdoms doctrine. It should be noted that the emperor must deal with secular matters like war and clergy must exhort Christians to fight as acts of piety. About the time of the siege of Vienna in 1529, Luther also began to view the Turkish threat in apocalyptic perspective. He was convinced that the rise of the Turks was foretold in the eschatological prophecies in scripture, especially Daniel 7. From the prophecy of Daniel 7, Luther concluded this determined reality that shaped his entire perspective on the Turks: The Turks would never conquer European Christianity. Furthermore, The study Quran afforded him the opportunity finally to engage Islam at its source. By exposing the errors of the Quran, Luther was convinced that German Christians would find their faith strengthened and could begin to offer the obvious evidence for the truth of the Christian religion. It is this correct purpose of Luther’s apologetic.

RFID 시스템과 웹으로의 확장

조용석(Cho, Yong-Seok),홍진근(Hong Jin Keun),한군희(Han Kun-Hee) 한국산학기술학회 2008 한국산학기술학회 학술대회 Vol.- No.-

최근 RFID 기술의 발달과 편의성으로 인하여 RFID 활용 시스템의 사용이 증가하고 있다. 본 논문에 서는 RFID와 더불어 전 세계적으로 많은 사용자를 확보하고 있는 Web과의 연동을 통하여 시스템 구 축 비용의 감소와 사용 편의성의 증대 그리고 활용의 확장성을 목표로 하였다.