Optimal Sampling Plans of Reliability Using the Co - mplex Number Function in the Complex System .

오충환,이종철,조남호 ( Chung Hwan Oh,Jong Chul Lee,Nam Ho Cho ) 한국품질경영학회 1992 품질경영학회지 Vol.20 No.1

포스터 전시회 : HCCI엔진의 과급 조건에서 EGR영향에 대한 수치해석

오충환 ( Chung Hwan Oh ),임옥택 ( Ock Taek Lim ) 한국액체미립화학회 2013 한국액체미립화학회 학술강연회 논문집 Vol.2013 No.-

This study investigates the EGR effect under the condition of intake boost pressure on homogeneous charge compression ignition (HCCI) combustion engine using numerical methods. The calculations were carried out using a single-zone model included in CHEMIKN-PRO. The detailed chemical-kinetic mechanisms and thermodynamic parameters for n-heptane and iso-octane from Lawrence Livermore National Laboratory (LLNL) were used for this study. Because changes in combustion phasing can significantly affect thermal efficiency, CA50 was maintained at 365°CA(5°CAaTDC). The results show that the EGR increase, the heat release was reduced. So the maximum pressure rise rate and IMEP were reduced. The EGR addition under the condition of intake boost pressure was maintain the IMEP higher than only add EGR.

胸痛의 形象醫學的 치료

오충환(Chung Hwan Oh),강경화(Kyung Hwa Kang),이용태(Yong Tae Lee) 한의병리학회 2006 동의생리병리학회지 Vol.20 No.5

HCCI엔진의 과급조건에서 EGR영향에 대한 수치해석적 연구

오충환(Chung Hwan Oh),나랑후 잠스란(Narankhuu Jamsran),임옥택(Ock Tack Lim) 대한기계학회 2014 大韓機械學會論文集B Vol.38 No.6

본 연구에서는 HCCI엔진의 과급조건에서 EGR의 영향에 대하여 수치해석적인 방법으로 연구하였다. 수치해석은 CHEMKIN-PRO에 있는 single-zone model을 사용하였고 연료로는 N-heptnae, Iso-octane 그리고 PRF50을 사용하였다. 사용된 연료의 화학반응 매커니즘과 열역학적 변수들은 Lawrence Livermore National Laboratory(LLNL)의 모델을 사용하였다. 연소상의 변화는 열효율에 큰 영향을 미치게 되므로 이영향을 배제하기 위해 본 연구에서는 CA50을 365oCA(5oCA aTDC)로 일정하게 고정하였다. 연구결과 EGR의 영향으로 줄어든 산소의 영향에 의해 저온산화반응과 NTC, 고온산화반응이 모두 약화되고 열발생률이 감소하는 것을 확인할 수 있었다. 과급과 EGR을 함께 사용하게 되면 과급에 의해 증가한 산소량과 연료의 영향으로 인해 연소가 강화되어 저온산화반응, NTC, 고온산화반응이 강화되고 열발생률이 증가하는 것을 확인할 수 있었다. EGR만을 사용하는 경우 IMEP가 감소하는 경향을 나타내지만 과급과 EGR을 함께 사용하는 경우 과급의 영향으로 인해 IMEP가 크게 증가하여 낮은 압력상승률과 높은 출력을 함께 얻을 수 있는 것을 확인하였다. This study used numerical methods to investigates investigate the exhaust gas recirculation (EGR) effect under the condition of boost pressure condition on a homogeneous charge compression ignition (HCCI) combustion engine using numerical methods. The detailed chemical-?kinetic mechanisms and thermodynamic parameters for n-heptane, iso-octane, and PRF50 from the Lawrence Livermore National Laboratory (LLNL) are were used for this study. The combustion phase affects the efficiency and power. To exclude these effects, this study decided to maintain a 50 burn point (CA50) at 5 CA after top dead center aTDC. The results showed that the EGR increased, but the low temperature heat release (LTHR), negative temperature coefficient (NTC), and high temperature heat release (HTHR) were weakened due by theto effect of the O2 reduction. The combined EGR and boost pressure enhanced the autoignition reactivity, . Hhence, the LTHR, NTC, and HTHR were enhanced, and the heat-release rate was increased. also In addition, EGR decraeased the indicated mean effective pressure ( IMEP), but the combined EGR and boost pressure increased the IMEP. As a results, combining the ed EGR and boost pressure was effective to at increase increasing the IMEP and maintaining the a low PRR .

The designed and Simplified Markov Models for Systems Based on Kronecker Algebra

오충환 ( Chung Hwan Oh ) 한국품질경영학회 1992 품질경영학회지 Vol.20 No.1

대중 매체시대, 대중예술의 미학적 가능성을 위한 연구

오충환(Chung-Hwan, Oh) 한국외국어대학교 철학문화연구소 2010 철학과 문화 Vol.21 No.-

본 글의 목적은 대중 매체 시대 대중예술을 위한 미학적 가능성을 검토해보는데 있다. 이를 위해 우선 문화와 예술의 관계를 검토해보고, 19세기 부르주아의 주요한 예술론이었던 개인의 창조와 예술의 자율성에 대해 비판하고 나섰던 역사적 아방가르드 예술관을 살펴보기로 하겠다. 아방가르드 예술가들의 핵심적인 슬로건은 “예술과 실제적 삶의 재통합”이었다. 하지만 이러한 재통합 전략은 사실상 실패로 끝나고 마는데, 이러한 전략이 실패한 결정적 이유는 해체하려고 했던 자율적 예술의 이념에 오히려 그들의 주장이 편입되었다는 것이다. 하지만 부르주아의 입장을 대변하여 삶과 예술을 분리하고 ‘예술을 위한 예술’ 혹은 자율적 예술을 주장한 낭만주의 예술관은, 현대 대중매체의 시대에 새로운 매체환경 속에서 일상생활과 예술 그리고 테크놀로지의 결합에 의해 나타나는 다양하고 새로운 예술장르와 작품들을 설명하기에는 많은 문제점이 있다. 현대의 예술은 그만큼 상호 영향을 미치며 발전하고 있으며 이러한 움직임에 보다 잘 부합되는 예술의 정의를 마련할 필요가 있을 것 같다. 이를 위해 전자매체 등장이후 우리의 지각방식이 어떻게 변했는지, 특히 디지털 시대에서의 지각방식은 어떤 특징이 있는지를 벤야민의 아이디어와 연관하여 살펴보려한다. 그리고 아방가르드의 슬로건이었던 “삶과 예술의 재통합”이 대중들의 일상적 지각과 관련하여 어떻게 발전할 수 있는지를 검토함으로써 오늘날 대중예술의 가능성을 모색해 보려한다. In this paper, I shall examine the claim that popular art is possible even in this age of mass media. First, I argue that 'arts' has to be given a new understanding. Advent of mass-media seems to require this. Older understandings of 'arts' cannot accommodate various forms of arts that are practiced in contemporary world, the mass media age where the daily life, arts and the new technologies are to be intertwined. Second, Walt Benjamin's approach is introduced. According to him, our perceptions about beautiful things have changed partly because of the technical reproduction. This notions of Benjamin's permit various art forms to be reproduced. I shall thus focus on his approach in this paper. I shall extend his approach to the perceptual mode of digital media technology. Third and finally, I examine the relation between actual life and arts. This investigation shall reveal that aesthetics about popular arts is possible after all. This should also shed light about which aesthetics shall be possible.

가시오가피가 흰쥐의 Collagen 유발 관절염 발생 및 치료에 미치는 영향

오충환 ( Chung Hwan Oh ),김순중 ( Sun Jung Kim ),서일복 ( Il Bok Seo ) 한방재활의학과학회 2005 한방재활의학과학회지 Vol.15 No.3

Objectives : This study was carried out to investigated the anti-pathogenetic and curative effects of Radix Cortex Acanthopanacis Senticosis (CAS) on collagen-induced arthritis in rats. Methods : In experiment Ⅰ, rats(n=30) were divided into normal group, porcine type II collagen immunized control group which taken with normal saline, and collagen immunized treated group which taken with extract of CAS. Body weight, paw edema volume, and thickness of ankle joint were measured at 0, 10, 15 days after immunization. At 15 days after immunization, serum TNF-α, IL-1β and anti-collagen IgG level were analysed, and histopathological examination was performed on the ankle joint. In experiment Ⅱ, rats(n=13) that were shown the gross lesions of collagen-induced arthritis, were divided into control group and treated group which taken with extract of CAS for 15 days after onset of arthritis. Items and methods of measurement were the same as experiment Ⅰ. Results : In experiment I, the results were as follows ; Arthritic score, paw edema volume, thickness of ankle joint, TNF-α, anti-collagen IgG of treated group were significantly decreased. In experiment Ⅱ, the results were as follows ; Paw edema volume, TNF-α, IL-1β, anti-collagen IgG of treated group were significantly decreased. Conclusions : These results indicated that CAS has the inhibitory effects on the incidence and progression of collagen-induced arthritis in rats.

END MILL 가공시 표면거칠기를 고려한 최적 절삭조건에 관한 연구

김성청(Sung Chung Kim),최재록(Jae Rok Chol),오충환(Chung Hwan Oh) 충북대학교 산업과학기술연구소 1992 산업과학기술연구 논문집 Vol.6 No.1

N/A

척수손상 환자에 대한 전기자극 인공사정의 초기 경험

강일규,조명관,오충환,문영태,김세철,최종한,Kang, Il-Gyu,Cho, Myoung-Kwan,Oh, Chung-Hwan,Moon, Young-Tae,Kim, Sae-Chul,Choi, Jong-Han 대한생식의학회 1992 Clinical and Experimental Reproductive Medicine Vol.19 No.1

From December 1991 to March 1992, 34 anejacuratory patients with spinal cord injury underwent 90 of electric stimulations with Seager NRH model 12. The average patient age was 43.5 years with a range of 23 to 48 years. The level of cord injury was cervical in 7, thoracic in 6, lumbar in 11, lumbosacral in 7 and conus medullaris in 3. The average number of electric stimulation per a patient was 2.65 with a range of 1 to 4. The average voltage and amplitude per a stimulation were 17.72 volts and 309. 89 mAmp with ranges of 5 to 25 volts and 50 to 500 mAmp. The total and motile sperm number were evaluated microscopically and analyzed statistically by paired t-test according to the frequency of electroejaculation, level of cord injury and voiding pattern. The results were obtained as follows. 1. An overall success rate of electroejaculation was 85.3% among 34 patients and 82.2% among 90 electric stimulations. 2. The total and motile sperm number per a stimulation were not correlated the frequency of electric stimulation, level of cord injury and voiding pattern. 3. Complications occured in 10 cases; severe low abdominal pain in 5, hypertension in 2, sweating in 1, headache in 1 and neck stiffness in 1. All the copmlications subsided spontaneously within 5 to 10 minutes after transient interruption of the electric stimulation. In summary, rectal probe electroejaculation is an accepted safe means of procuring sperm from spinal cord injury patients with ejaculatory incompetence. However very poor sperm motility was found and it was not related with the frequency of electroejaculation, level of cord injury and voiding pattern. Further investigation would be needed to conclude and to identify the reasons for impaired sperm motility.

포스터 전시회 : 분사압력 변화에 따른 디젤-DME연료의 다단분사 특성에 관한연구

정연호 ( Yun Ho Jeong ),양지웅 ( Ji Woong Yang ),오충환 ( Chung Hwan Oh ),임옥택 ( Ock Taeck Lim ),정수진 ( Soo Jin Jeong ),오세두 ( Se Doo Oh ) 한국액체미립화학회 2013 한국액체미립화학회 학술강연회 논문집 Vol.2013 No.-

An investigation on spray characteristics of fuels which diesel and di-methyl ether(DME) with change of injection pressure used the multi-injection in constant volume combustion chamber(CVCC). Diesel was already used famous fuel which we could use. DME showed similar features with diesel like as cetane number, auto-ignition temperature. High cetane number of diesel and DME could make possible to compression ignition. DME showed different atomization from diesel due to evaporating pressures and boiling points. Experiments were carried out in CVCC equipped with Delphi solenoid 6-hole type injector and the spray characteristics of diesel and DME were tested the various pre and pilot injection. Terms of injections and a number of injections in multi-injection has been controlled. Experiments were performed in 2 types that 1500rpm , 2000rpm and under the condition of injection ranging from 100bar to 500bar. From the results of this experiment diesel showed longer spray penetration than DME. That result showed different of atomization speed DME and diesel. Result of high injection pressure condition showed similar spray characteristics diesel and DME. After this investigation, possibilities of the using the DME in fuel business would be expected.