음향방출기술에 의한 밸브누설평가 연구(1)

이상국,이선기,이준신,박종혁 한국비파괴검사학회 2004 학술대회 논문집 Vol.- No.-

The objective of this study is to estimate the feasibility of acoustic emission method for the internal leak from the valves. In this study, valve leak tests using various types of specimen simulated seat damage were performed in order to analyzer acoustic emission properties when leaks arise in valve seat. As a result of leak test for specimens simulated valve seat, we conformed that leak sound level increased in proportion to the increase of hole diameter and leak velocity, and decreased in proportion to the increase of leak depth. And also, leak sound level has hysteresis for leak velocity. From the experimental results, it was suggested that the acoustic emission method for monitoring of leak was feasible.

공정변수의 변동을 고려한 호감도 함수를 통한 다중반응표면 최적화

권준범,이종석,이상호,전치혁,김광재 한국경영과학회 2005 한국경영과학회지 Vol.30 No.1

A desirability function approach to a multiresponse problem is proposed considering process parameter fluctuation which may amplify the variance of response. It is called POE(propagation of error), which is defined as the standard deviation of the transmitted variability in the response as a function of process parameters. In order to obtain more robust process parameter setting, a new desirability function is proposed by considering POE as well as distance-to-target of response and variance. The proposed method is illustrated using a rubber product case in Ribeiro et al. (2000).

관상동맥 스텐트 내 재협착의 발생에 미치는 임상적 관동맥 조영술적 요인들

윤혁준,김기식,박형섭,이영수,현대우,한성욱,허승호,김윤년,김권배,박남희,원경숙 대한순환기학회 2003 Korean Circulation Journal Vol.33 No.12

흰쥐에서 음경발기 평가의 척도로서 음경해면체내압측정술 확립

송윤섭,김용준,이광우,김준모,문기혁,박영호,민영기,유형균,김형건 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.1

Purpose: Because studies about the control of penile erection at the entral nervous system was dependent on the animal experiments, establishment of measuring penile erection is important to evaluate the effects changes at the central nervous system on the penile erection. Intracavernous pressure measurement in rats has been introduced as a suitable index for the evaluation of penile erection but this method is invasive and technically difficult. So, we established the intracavernous pressure measurement in rats as the experimental index for penile erection. Materials and Methods: 42 male adult Sprague-Dawley rats (250-300gm) were divided to saline or papaverine treated group. Rats were placed on a heating table to maintain their body temparature and anesthetized with 50mg/kg of pentobarbital sodium by intraperitoneal injection. A cannula was inserted to the left carotid artery to measure systemic blood pressure. Saline (0.05, 0.1ml), papaverine(0.05, 0.1, 0.25, 0.5, 1.0, 2.0mg) were injected intracavernously via 26 guage needle filled with saline or papaverine which connected to pressure transducer and polygraph was inserted into the corpus cavernosum on one side to inject the drug and to measure intracavernous presure. Results: Properly executed insertion and intracavernous administration produced a instantaneous but transient rise in intracavernous pressure that substantially stabilized and maintained at 5.4±0.4mmHg. Intracavernous pressure and duration of penile blood flow following intracavernous injection of papaverine are increased comared to those of saline. Conclusions: Monitoring intracavernous pressure in rats represents a suitable index for the evaluation of penile erection in small laboratory animals.

노인외상환자의 예후 인자

문철규,전정민,최성혁,문준동,이성우,홍윤식 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: It has been documented that certain prognostic factors may affect the outcomes of the old aged victims by trauma. Considering that trauma is the sixth most common cause of death in people over the age of 65 years and there is a rapid growth of elderly population, it is paramount to understand the prognostic factors when dealing with geriatric trauma patients. Hypothesis and Goals: It can be hypothesized that the prognostic factors should be determined independently between populations being consisted of different races, countries, socio-economic states, cultures, or so on. Thus, the study was designed to evaluate the factors affecting the outcomes of elderly Korean trauma patients. Methods: One hundred forty six patients aged over 65 years were retrospectively reviewed, who visited the Emergency Center of Korea University from January, 1997 to June, 1998. Of 146 patients, 7 were excluded due to discharge against advice or transfer to the other hospitals. Parameters analyzed were age, sex, mechanism of injuries, body region injured, Injury Severity Score (ISS), previous medical illness, hospital morbidity, duration of hospital stay, and cost. Each patient was classified into improved or not-improved group depending on the outcomes, and young-old or old-old group depending on the age. The factors affecting the hospital stay in improved patients were analyzed in the parameters of previous medical illness, hospital morbidity, multiple injuries, ISS, and age. All statistical tests were conducted with two-tailed levels of 0.05. Results: Of 139 patients, the mean age was 74±7.1 years, mean ISS 9.3±7.26, mean hospital stay 27±27.1 days. Most commonly injured body region was the extremities due to fall from a level surface. Rate of previous illness showed 0.94 medical diseases per person and were aggravated after trauma in 39 patients (60.9%). Hospital morbidity rate was 0.46 incidents per person. There were no differences in age and duration of hospital stay between the improved and the not-improved group. Substantial differences were noted in affected body region, incidence of previous illness, and hospital morbidity between the groups (p=NS). Not-improved group had higher ISS(p<0.05). ISS, previous illness and hospital morbidity affected the duration of hospital stay in the improved group. Hospital stay was 40±25.1 days in patients with ISS over 6 while 6±8.6 days in those with ISS 5(p<0.05). Hospital stay in the improved was 26±26.9 days while 31±24.8 days in the improved old-old group (p=NS). Hospital stay in the young-old minor trauma (ISS5) patients with previous illness and hospital morbidity was 26±10.1 days while 4±7.3 days in those without previous illness and hospital morbidity (p<0.05). Conclusion: Previous medical illness and hospital morbidity, not age, are predictive of outcomes of geriatric trauma patients with respect to hospital stay. As most of the hospital morbidity was a trauma-induced aggravation of previous medical illness and hospital morbidity contributing poor outcomes can be potentially avoidable, routine aggressive care for the geriatric trauma patients with previous medical illnesses is needed.

페니실린 내성 폐렴구균 균혈증의 임상적 특성

정두련,송재훈,김은옥,류지소,이남용,이혁,백경란,김성민,배직현,우준희,김양수 대한감염학회 1997 감염 Vol.29 No.4

목적: 지역사회 획득 감염의 매우 흔한 원인균인 폐렴구균의 페니실린 및 다른 항균제에 대한 내성의 증가는 세계적으로 문제가 될 뿐 아니라 국내에서 더욱 큰 문제로 대두되고 있다. 본 연구는 항균제 내성 여부에 따른 폐렴구균 균혈증의 임상적 특성 및 위험 요인를 분석하여 항균제 내성의 임상적 의미를 조사하고자 시행되었다. 방법:1989년부터 1994년까지의 폐렴구균 균혈증 41례를 대상으로 하여 의무기록지를 조사하였다. 균주의 항균제 감수성 검사는 oxacillin 디스크 확산법으로 페니실린 내성 여부를 거사한 후, 한천 희석법을 이용하여 페니실린을 비롯한 11개의 항균제의 MIC (minimal inhibitory concentration)를 구하고 감수성 여부를 판정하였다. 결과: 41균주 중 68.3%가 페니실린에 대하여 내성(중등도 12.2%, 고도 56.1%)을 보였으며 다제내성률은 61%였다. 특히 소아에서는 100%(고도 88.2%)의 내성률을 보여 성인보다 내성률이 더 높았다. 페니실린 내성 균주는 대부분 다른 β-lactam 항균제에도 내성을 보였으며 특히 페니실린 고도 내성 균주는 cefotaxime, ceftriaxone에 대하여 100% 내성을 보였고 imipenem에 대해서도 95.5%의 중등도 내성률을 보였다. 혈청형은 19와 23이 많았고 그 외에 6이 있었다. 임상적 특성의 분석상 환자들의 연령분포는 3개월부터 82세까지였으며 기저질환을 가지고 있는 환자가 56%이었으며 지역사회 획득 감염이 71%였다. 균혈증의 일차감염원은 폐렴(22례, 54%)과 수막염(5례, 12%)이 가장 많았다. 페니실린 내성의 위험요인으로는 소아 연령만이 유의한 요인으로 분석되었다. 항균요법에 대한 반응을 볼 때 실패한 경우는 고도 내성 군의 20%에서만 있었으며 병원내 총사망률은 페니실린 감수성 군이 30%, 중등도 내성 군이 20%, 고도 내성 군이 13.6%로서 유의한 차이는 없었다. 결론: 페니실린 내성 폐렴구균은 국내에 만연하고 있으며 높은 다제내성률을 보였다. 이들은 대개 지역 사회 획득 감염을 일으키는데 균혈증의 경우 그 사망률은 내성 여부에 따른 차이를 보이지 않았다. 소아연령만이 페니실린 내성의 위험요인으로 분석되었다. Background: The emergence of penicillin-resistant Streptococcus pneumoniae (PRSP) poses serious therapeutic problem in clinical practice, especially in cases with bacteremia or meningitis. Methods: To investigate clinical characteristics of bacteremic pneumococcal diseases due to PRSP, we retrospectively analyzed 41 cases with cocumented bacteremic diseases seen in a tertiary care hospital between 1989 and 1994. Results: Agar dilution test of 41 strains isolated showed that 68.3% of S. pneumoniae were PRSP [high-level resistance(R) 56.1%, intermediate resistance(I) 12.2%]. High-level resistant strains were not susceptible to other β-lactam agents, whereas isolates of penicillin-susceptible S. pneumoniae(PSSP) were uniformly susceptible to all β-lactam agents. Predominant serogroups of PRSP were 19, 23, and 6. Bacteremic diseases caused by PRSP included pneumonia (22), meningitis (5), peritonitis (3), acute otitis media (2), acute tonsillitis (2), endocarditis (1), pyelonephritis(1), and primary bacteremia(5). Children were more likely to be infected with PRSP with high-level or intermediately resistant strains than were adults(P=0.0001), but no differences were seen between PRSP and PSSP regarding sex. previous antibiotic history, previous hospitalization, and underlying immunocompromised conditions. Most cases were community-acquired (R 78.3%, I 60%, S 61.5%). Fatality rates of patients infected with PRSP were not different significantly from PSSP (22.6% vs. 30%). However, most fatal cases had underlying immunocompromised conditions. Conclusion: PRSP is widely prevalent in Korea and shows resistance to most antibiotics. It causes community-acquired bacteremic diseases with poor outcomes, but there was no difference in mortality between patients infected with PRSP and PSSP. Pediatric age was the only risk factor for penicillin resistance.

Synthesis of carbon nanotube fibers using the direct spinning process based on Design of Experiment (DOE)

Lee, Sung-Hyun,Park, Junbeom,Kim, Hye-Rim,Lee, Taeseon,Lee, Jaegeun,Im, Yong-O.,Lee, Cheol-Hun,Cho, Hyunjung,Lee, Hyeseon,Jun, Chi-Hyuck,Ahn, Yu-Chan,Lee, In-Beum,Lee, Kun-Hong Elsevier 2016 Carbon Vol.100 No.-

<P>The optimum synthesis conditions for carbon nanotube (CNT) fibers were investigated using the Design of Experiment (DOE) technique. Direct spinning processes are governed by a variety of experimental factors: the methane flow rate, ferrocene flow rate, sulfur flow rate, hydrogen flow rate, water flow rate, and reaction temperature. The process was optimized in two stages that addressed first the Fractional Factorial Design (FFD) and then the Response Surface Methodology (RSM). Results from each experiment were classified according to a 6-step rating system: nothing(1), black gas(2), dust(3), ribbon or film(4), fiber(5), or continuous fiber(6). In the first step, three major factors (methane, sulfur, temperature) were identified as important among the six experimental factors tested using FFD. The effects of the major factors and the interactions were analyzed through the main effect plot and the interaction plot. In the second step, the experimental conditions were optimized using a model equation derived from Box-Behnken design experiments. Finally, the CNT fibers were continuously synthesized under the optimum conditions. The synthesized CNT fibers mainly consisted of single-walled CNTs (SWCNTs) 1.2 -3.8 nm in diameter. The I-G/I-D ratio of the CNT fibers was 48. This work provides a useful methodology for synthesizing the CNT fibers. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Effects of antifreeze proteins on the vitrification of mouse oocytes: comparison of three different antifreeze proteins

Lee, Hyang Heun,Lee, Hee Jun,Kim, Hak Jun,Lee, Jun Hyuck,Ko, Yong,Kim, Sun Mie,Lee, Jung Ryeol,Suh, Chang Suk,Kim, Seok Hyun Oxford University Press 2015 Human reproduction Vol.30 No.9

Comparative Genomic Study of Polar Lichen-Associated Hymenobacter sp. PAMC 26554 and Hymenobacter sp. PAMC 26628 Reveals the Presence of Polysaccharide-Degrading Ability Based on Habitat

Lee, Jun Hyuck 극지연구소 2021 극지연구소 초록집 Vol.- No.-

Inhibitory Effect of RANKL-Induced Osteoclast Differentiation and ROS Generation by Sphaerotylus antarcticus Extract

Lee, Jun Hyuck,Ko, Young Wook,Kim, Sanghee 극지연구소 2023 극지연구소 초록집 Vol.- No.-