레이저를 이용한 알루미늄 합금과 스테인리스강의 용접

이철구,채병대 한국공작기계학회 2005 한국생산제조학회지 Vol.14 No.2

A feasibility study was performed to see the welding possibility of dissimilar thin-plat materials. These materials were welded for finding the optimum welding condition, and evaluating the soundness of welding zone. The welding was attempted under the condition of laser power 500~600W, pulse width 1.0~2.5ms and frequency 11~18Hz. In this study, the highest tensile-shear strength was observed at laser the low frequency. The suitable welding condition can be obtain at the large pulse width and the low frequency.

PCR을 이용한 국내 및 수입 축산물 유래 Listeria monocytogenes의 유전학적 분석연구

우용구,이수화,이철현,최정수,류재두,김영일,이오수,김봉환 한국수의공중보건학회 2003 예방수의학회지 Vol.27 No.2

One hundred-fifty two of Listeria strains were isolated from domestic chicken carcasses, a slaughter-houses from nationwide from 1996 to 1997 and imported livestock products from a ten foreign countries including the USA, China, France and Thailand. To substitute the laborious and time consuming procedures of clinical laboratory standard diagnostic methods, the rapid and specific multiplex PCR(M-PCR), which was designed to amplify a three kinds of genes simultaneously f3r specific detection and differentiation of L. monocytogenes(LM) by one step procedure, was established. The LM strains confirmed with M-PCR were analysed to their genetic diversities by RAPD using the two primers(D87 & MMTl), and also evaluated on their discriminatory abilities(na) between two primers. our study also conducted the REP-PCR and ERIC-PCR for evaluation of the possibility of REP and ERIC elements for genetic subtyping of LM strains. According to the REP-PCR and ERIC-PCR fingerprinting patterns, LM strains were divided into 7(ERIC-type) and 4(REP-type) major clusters at the relative clone cut off value of 80%. According to the computer analysis of PCR results using the GelCompar Ⅱ software, ERIC-PCR(DI=0.955) had expressed the most high discriminatory ability and followed by REP-PCR(DI=0.952), RAPD(D87; 0.954, MMT1; 0.937), in order. The combined analysis of the present PCR results was also expressed the reliable and useful discriminatory ability(DI=0.916). This study suggested that PCR based methods could be used as an reliable, reproducible, rapid, and highly discriminatory method for the genetic differentiation of genus Listeria.

May-Thurner Syndrome 환자의 좌측 하지 심부정맥혈전증 : Pigtail 카테터 회전을 이용한 치료의 효용성과 안전성 Lower Extremity Deep Vein Thrombosis of May-Thurner Syndrome

정구용,염차경,이주호,강병철 대한혈관외과학회 2004 Vascular Specialist International Vol.20 No.1

합성수지의 접합

정규창,이철구 서울산업대학교 산업대학원 1996 大學院論文集 Vol.4 No.-

The joining of polymer materials can be mechanically fastened or adhesively bonded, but they can also be welding. Mechanical fastening is an expensive multistep operation which creates stress concentrations in the part. It provides good assurance for the quality and strength of the joint. Adhesively bonded joints have more uniform load distributions than bolted joints. Surface preparation for good wetting of the adhesive is very critical to the process. Inspection of the bond is usually required. Welding or fusion bonding is restricted to polymer materials only, and it requires heating and melting of the thermoplastic. Welded joints, like adhesively bonded joints, have more uniform load distribution than bolted joints. At present, inspection of the welded joint is usually required, however closed loop controls should soon eliminate that requirement. The theory and practice behind joint design and the use of mechanical fastening, adhesive bonding, and welding are discussed.

초등 교육 발전에 기여하는 교육대학의 현장지도 역할에 관한 연구

김성회 / 이종철 / 전구호 / 정용팔 / 최동준 / 문낙주 공주교육대학교 초등연구원 1977 公州敎大論叢 Vol.13 No.2

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중증 외상환자에서 염기 결핍수치의 유용성

문준동,김수진,문철규,최성혁,전정민,이성우,홍윤식 대한응급의학회 2001 대한응급의학회지 Vol.12 No.3

Background: This study's objective was to determine the prognostic value of the base deficit measured in the emergency department(ED) and to determine whether base deficit can provide information not provided by advanced injury scoring system. Methods: This study was a retrospective analysis of data collected for two years. Thirty-two severe trauma patients who were admitted to the Emergency Department of Korea University Hospital were included in this study. The patients were divided into two groups: the normal base deficit group(-3 mmol/L to 3 mmol/L) and the elevated base deficit group(>3 mmol/L). The base-deficit value, age, sex, head injury, organ failure rate, and survival were considered, and the also Revised Trauma Score(RTS), Acute Physiology And Chronic Health Evaluation(APACHE II), and Injury Severity Score(ISS) were measured. Result: The elevated base-deficit group showed a lower survival rate and a higher organ failure rate compared to the normal base deficit group. Logistic Regression showed a strong association between base deficit and mortality rate. Among the previous injury scoring Systems(RTS, APACHE II, ISS), base deficit had the strongest correlation with RTS. By using base deficit value and the RTS together, we obtained a higher positive predictive value than that obtained by using base deficit or RTS alone. Conclusion: The admission value of the base deficit in the ED is a useful tool in predicting the outcome in severe trauma patients, and it can be an adjunct to previous injury scoring systems. As an advanced injury scoring System is developed in the future, the base deficit may have some significant role.

쇼트피닝 가공 최적조건 탐색을 위한 실험적 연구

신용승,김태형,윤종학,노승남,이철구 서울産業大學校 2002 논문집 Vol.53 No.1

The shot peening process is most often used to improve fatigue properties of metal parts. In order to achieve optimum, repeatable and reliable fatigue enhancement from the shot peening process, the important shot peening parameters must be controlled. In this paper, the optimum shot peening condition is investigated. Rotary bending fatigue test was accomplished to investigate the effects of shot peening on the fatigue strength. Experimental results show that the fatigue strength was tremendously increased by optimum peening.

피로와 의료이용, 업무상 사고 및 질병결근

장세진,고상백,강동묵,김성아,정진주,이철갑,강명근,현숙정,조정진,차봉석,박종구 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Objectives: This study examined the relationship of fatigue to medical utilization, occupational accident and sickness absence. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project, 2002~2004). A total of 30,146 employees categorized within the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were recruited. A structured-questionnaire was used to assess the participants' sociodemo-graphics, job-related factors, health-related behaviors, personality trait, self=perceived fatigue (MFS) and the frequency of medical utilization, occupational accident and sickness absence. Data on medical utilization and occupational accident were confirmed from company health records. Chi-square test and logistic regression analysis were used to elucidate the relationship of self-perceived fatigue to medical utilization, occupational accident and sickness absence. Results: In logistic regression analyses, self-perceived fatigue was associated with medical utilization (outpatient), occupational accident and sickness absence although the strength of the associations was higher in the blue collar workers except for medical utilization. For medical utilization, the white collar worker's adjusted odds ratios of outpatient utilization for workers scoring in the third quartile and the highest quartile, compared to workers scoring in the lowest quartile were 1.50 (95% CI: 1.20-1.87) and 2.16 (95% CI: 1.69-2.75), respectively. The blue collar workers' adjusted odds ratios of outpatient utilization for workers scoring in the second (OR: 1.23, 95% CI: 1.06-1.43), third (OR: 1.42, 95% CI: 1.22-1.66) and highest quartile (OR:1.83, 95% CI: 1.55-2.17), respectively, compared to workers scoring in the lowest quartile were statistically significant. However, no associations were found between fatigue and inpatient utilization for either the white or blue collar workers. The blue collar workers' adjusted odds ratios of being injured for workers scoring in the second, third and highest quartile were 1.41 (95% CI: 1.00-2.00), 1.57 (95% CI: 1.10-2.22) and 2.41 (95% CI: 1.69-3.44), respectively, compared to those scoring in the lowest quartile, but, those of the white collar workers were not significant. There was more likely to an increased risk of sickness absence in workers scoring in the second, third and highest quartile compared to those scoring in the lowest quartile in both white and blue collar workers, but the magnitudes of risk were higher in the blue collar workers than the white collars workers. Conclusion: This result suggests that fatigue is a determinant predictor of medical utilization, occupational accident and sickness absence, and that the pattern of risks for the three outcomes differs according to the occupational type. Some limitations of this study and considerations for future study were also discussed.

Efficacy of sonic-powered toothbrushes for plaque removal in patients with peri-implant mucositis

Lee, Jungwon,Lim, Jong Heun,Lee, Jungeun,Kim, Sungtae,Koo, Ki-Tae,Seol, Yang-Jo,Ku, Young,Lee, Yong-Moo,Rhyu, In-Chul Korean Academy of Periodontology 2015 Journal of Periodontal & Implant Science Vol.45 No.2

Purpose: The aim of this study was to evaluate the effectiveness of powered toothbrushes for plaque control in patients with peri-implant mucositis, in comparison with manual toothbrushes. Methods: This randomized, prospective, controlled, clinical parallel study compared the efficacy of manual and powered toothbrushes for plaque control in implant restorations. Patients with bleeding on probing, no residual pocket depth (as indicated by a pocket probing depth ${\geq}5mm$), and no radiological peri-implant bone loss were eligible for this study. Patients were requested to complete a questionnaire describing their oral hygiene habits. The duration and frequency of tooth brushing were recorded by subjects in order to assess their compliance. Clinical parameters, including the modified plaque index (mPI), the modified sulcus bleeding index (mSBI), and clinical photographs (buccal and lingual views) were recorded at baseline and at one-month and two-month follow-up visits. Results: Statistically significant differences between patients who used manual toothbrushes and those who used powered toothbrushes were found regarding the frequency of tooth brushing per day and the duration of brushing at one-month and two-month follow-up visits, while no statistically significant differences were found relating to other oral hygiene habits. A statistically significant difference in patient compliance for tooth brushing was found at one month, while no difference was found at two months. Statistically significant decreases in the mPI and the mSBI were observed in both groups from baseline to the one- and two-month follow-ups. The overall reduction of these parameters was not significantly different between the two groups, except for mPI reduction between baseline and one month of follow-up. Conclusions: Sonic-powered toothbrushes may be a useful device for plaque control in patients with peri-implant mucositis.

Increased Plasma Nitric Oxide Metabolites in Suicide Attempters

Lee, Bun-Hee,Lee, Sung-Woo,Yoon, Dokyung,Lee, Heon-Jeong,Yang, Jong-Chul,Shim, Se-Hoon,Kim, Do-Hoon,Ryu, Seung-Ho,Han, Changsu,Kim, Yong-Ku S. Karger AG 2006 Neuropsychobiology Vol.53 No.3

<P><I>Objective:</I> To evaluate any correlation between plasma levels of nitric oxide metabolites (NO<SUB>x</SUB>) and suicide attempt. <I>Method:</I> Plasma NO<SUB>x</SUB> levels were measured in 53 patients who had recently attempted suicide, 58 nonsuicidal psychiatric patients, and 75 normal controls. The severity of suicidal behaviors was evaluated using Weisman and Worden’s Risk-Rescue Rating Scale. <I>Results:</I> Plasma NO<SUB>x</SUB> levels were significantly higher in suicidal patients than nonsuicidal psychiatric patients or normal control subjects (F = 11.029, d.f. = 2, 183, p < 0.001). Among the patients with a diagnosis of major depression, suicidal depressive patients had significantly higher plasma NO<SUB>x</SUB> levels than nonsuicidal depressive patients (t = -3.090, d.f. = 84, p = 0.003). <I>Conclusion:</I> Our study suggests that increased NO production in plasma is associated with suicide attempt, especially in depressive patients.</P><P>Copyright © 2006 S. Karger AG, Basel</P>