음향초음파와 음향방출에 의한 복합재료-금속 접착접합부의 피로손상 평가

권오양,이경주 한국비파괴검사학회 2001 한국비파괴검사학회지 Vol.21 No.4

복합재료-금속 접착접합부가 사용 중 반복 하중을 받을 때 발생하는 피로 손상도를 음향초음파(acousto-ultrasonics; AU)법과 음향방출(acoustic emission; AE)법을 이용하여 평가하였다. 피로시험에는 단일겹치기(single-lap) 시험편을 사용하였으며, AU법을 통해 취득한 신호로부터 음향초음파변수(acousto-ultrasonic parameters; AUP)와 피로손상과의 상관관계 곡선을 얻고, AE법에서는 누적 AE events를 통한 피로손상과의 상관관계 곡선을 얻어, AU법과 AE법의 결과를 비교하였다. 이 곡선들은 피로손상에 의한 고분자기지 복합재료의 강성 저하(E/E0)를 나타내는 곡선과 매우 유사하며, 이를 바탕으로 피로 손상도의 예측과 잔여 수명의 예측이 가능하다. 또한 피로 하중의 초기 단계와 피로손상의 누적에 의해 급격한 변화가 나타나는 단계의 파형과 주파수 성분을 비교하여, 피로 파괴의 마지막 단계에서 나타나는 신호 중에는 본격적인 피로손상에 의해 발생하는 AE 신호 성분이 포함되어 있음을 확인할 수 있었다. A correlation between fatigue damage and acousto-ultrasonic (AU) parameters has been obtained from signals acquired during fatigue loading of the single-lap joints of a carbon-fiber reinforced plastic (CFRP) laminates and as A16061 plate. The correlation showed an analogy to those representing the stiffness reduction (E/E0) of polymer matrix composites by the accumulation of fatigue damage. This has been attributed to the transmission characteristics of acoustic wave energy through bonded joints with delamination-type defects and their influence on the change of spectral content of AU signals. Another correlation between fatigue cycles and the spectral magnitude of acoustic emission (AE) signals has also been found during the final stage of fatigue loading. Both AU and AE can be applied almost in real-time to monitor the evolution damage during fatigue loading.

Streptomyces thermocyaneoviolaceus의 Xylanase 생산조건 및 Xylooligo당의 생산

주길재,박희동,최준호,이인구,이오석,권달호 慶北大學校農業科學技術硏究所 1998 慶北大農學誌 Vol.16 No.-

농산폐자원으로부터 기능성물질인 xylooligo당을 생산하기 위해서 내열성 균주인 S.thermocyaneoviolaceus가 생산하는 xylanase의 생산최적조건을 검토한 결과 0.8% 밀기울, 0.06% yeast extract, 0.06% bactopeptone, 0.05% MgSO₄·7H₂O, 0.005% FeSO₄·7H₂O, 0.05% KH₂PO₄및 0.2% K₂HPO₄를 함유한 배지(pH7.0)에서 50℃, 24시간 배양시 최고효소활성(2.47 unit/ml)의 배양상징액을 얻을 수 있었다. 효소의 최적반응조건은 pH5.5, 65℃였다. 또한 pH안정성을 조사한 결과 pH4.5∼9.5사이에서 4℃에서 12시간후에도 80% 이상의 효소활성을 유지하였고, 열 안정성은 60℃에서 1시간 처리후 94%이상의 효소활성을 유지하는 내열성이 있는 효소였다. 생산된 xylanase birchwood xylan 반응생성물을 TLC 및 HPLC로 확인해 본 결과, pH가 낮을수록(pH 5.0∼6.0) xylobiose와 xylotriose및 소량의 xylose의 양이 증가하였고, pH가 높을수록 (pH8.0∼9.0) X₄이상의 각종 xylooligo당의 양이 상대적으로 증가하였다. 또한 24 시간후에는 xylan의 상대량이 25% 이하로 감소하면서 주분해산물로 xylobiose가 생산되었으며 xylotriose와 xylose 및 X₄이상의 각종 xylooligo당이 생산되었다. A thermotolerant bacterium, Streptomyces thermocyaneoviolaceus which produced xylan-degrading enzymes, utilized excellently xylan of wheat bran by producing the enzymes in comparison with that of birchwood or oat spelts. Optimal enzyme production was achieved in WB medium containing 0.8% wheat bran, 0.06% yeast extract, 0.06% bactopeptone, 0.05% MgSO₄·7H₂O, 0.05% FeSO₄·7H₂O, 0.05% KH₂PO₄ and, 0.2% K₂HPO₄(pH 7.0) at 50℃ for 24 hrs. The optimal pH and temperature for the hydrolysis of xylan were pH 5.5 and 65℃, respectively. The enzyme activity was retained more than 80% at the range from pH 4.5 to pH 9.5 at 4℃ for 12 hrs and 94% on the heat-treatment at 65℃ for 1 hr. Xylobiose, xylotriose, xylose, and other xylooligosaccharides were produced as end products from hydrolysis of birchwood xylan by the xylanase of S. thermocyaneoviolceus.

학습목표 성취를 위한 CAI 프로그램의 개발

주경수,권오석 순천향대학교 1994 논문집 Vol.17 No.1

We planned 5 grade mathematics fraction by CAI program in order to help the accomplishment of learning by the correct knowledge of learning objection. We are embodied by making use of GREAT with authoring tools. This was that heteogeneous students were able to shorten learning period in the circumstances of learning in a class room, to extend remarkably personal ability with individual learning adjust to each student. In addition to, we made a program so as to compensate for high level process for superior student, the supplementation of learning less for inferior students.

Effects of Dietary Fatty Acids on Serum Lipids and Fatty Acid Composition of Serum Phospholipids in Men

Oh,Eun-Joo,Kwon,Jong-Sook,Chang,Yu-Kyung 韓國營養學會 1997 Journal of Nutrition and Health Vol.30 No.4

웨이블릿 변환 노이즈 제거에 의한 AE 위치표정

이경주,권오양,주영찬 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.6

사용하는 탄성파의 파장과 두께가 비슷하거나 보다 얇은 박판 구조에서 음향방출(acoustic emission, AE)신호의 위치표정 정확도의 향상을 위해 새로운 신호처리 방법인 웨이블릿 변환 디노이징(wavelet transform de-noising) 기법을 도입하였다. 탐지된 AE 신호에 대하여 웨이블릿 변환과 역변환을 수행하여 상대적으로 저주파수이고 큰 진폭을 갖는 굽힘과 성분(flexural component)은 활용하고, 고주파수이고 작은 진폭의 팽창파 성분(extensional component)은 필터링하여 제거한 다음 신호를 재구성하는 디노이징 처리를 거침으로써 박판에서의 위치표정 시 발생하는 도달시간차 측정오차를 최소화할 수 있음을 확인하였다. 따라서 웨이블릿 디노이징 처리를 도입함으로써 위치표정의 정확도가 게인(gain)이나 문턱값의 설정, 판의 두께, 센서간거리, 발생원과 센서의 상대적인 위치에 무관하고 전통적인 문턱값 등과 방법에 비하여 월등하게 향상되었다. 또한 상대적으로 매우 큰 진폭을 가지는 굽힘과 성분을 활용하므로 실제적인 박판 구조물에서의 위치표정에 효과적으로 활용될 수 있을 것이다. A new technique for the source location of acoustic emission (AE) in plates whose thichness are close to or thinner than the wavelength has been studied by introducing wavelet transform de-aoising technique. The detected AE signals were pre-prossed using wavelet transform to be decomposed into the low-frenquency, high=amplitude flexural components and the high-frequency, low-amplitude extensional components. If the wavelet transform de-noising was employed, we could successfully filter out the extensional wave component, one of the critical errors of source location in plates by arrival time difference method. The accuracy of source location appeared to be significantly improved and independent of the setting of gain and threshold, plate thickness, sensor-to-sensor distance, and the relative position of source to sensors, Since the method utilizes the flexural component of relatively high amplitude, it could be applied to very large, thin-walled structures in practice.

비선형방정식을 이용한 이방성판의 음향방출 위치표정

이경주,권오양 한국비파괴검사학회 2001 한국비파괴검사학회지 Vol.21 No.3

2차원 음양방출 위치표정에서 전통적인 방법으로 문턱 전압값을 설정하여 도달시간차를 측정함으로써 2개의 쌍곡선을 형성하는 데는 해당 구조물에서 직접 측정한 속도를 이용하게 된다. 복합재료 적층판과 같은 이방성 재료에서는 섬유의 배열방향에 따라 탄성계수 변하므로 속도가 섬유의 방향성에 의존하게 된다. 따라서 임의의 위치에서 발생한 탄성파의 도달시간차 측장에 의한 위치표정의 오차가 커지며, 위치표정의 과정이 복잡해지는 것을 피할 수 없다. 본 연구에서는 전통적인 음향방출 위치표정에서 쌍곡선의 2중 교점의 오차를 정정하기 위해 사용되어야 하는 제 4의 센서를 사용하지만 속도변화에 기인하는 위치표정의 오차를 줄일 수 있는 방법으로 수치해석에 의해 비선형방정식을 풀어내는 위치표정 알고리즘을 제안하였다. 또한 제안된 방법이 전총적인 방법에 비해 이방성 판에서의 2차원 위치표정을 보다 간단하게 수행하고, 정확도를 향상할 수 있는 방법임을 실험적으로 입증하였다. For the conventional two-dimensional source location of acoustic emission (AE) based on the threshold crossing, wave velocity has to measured in the actual structure to calculate the arrival-time difference and thus to form the two hyperbolae. Velocity is dependent on the fiber orientation, however, due to the dependence of elastic modulus on fiber orientation in anisotropic materials such as composite plates. This can affect the accuracy of AE source location and make the source location procedure complicated. In this study, we propose a method to reduce the location error in anisotropoic plates by using the numerical solution of nonlinear equations, where the velocity term has been removed by employing the fourth sensor. The efficiency and validity of the proposed method has also been experimentally verified.

관상동맥 질환에서 CD14 유전자형에 따른 세균 및 Heat Shock Protein에 대한 반응의 차이

한주용,최수연,조현주,김화평,강현재,구본권,김남중,김효수,손대원,오병희,박영배,최윤식 대한감염학회 2007 감염과 화학요법 Vol.39 No.1

Background : CD14 is the receptor for lipopolysaccharides and heat shock protein (HSP), which has been suggested being associated with increased risk of coronary artery disease (CAD). We investigated whether the response to infectious agents or HSP is different according to CD14 polymorphism in Koreans. Materials and Methods : Antibody titers to Helicobacter pylori, Chlamydia pneumoniae, and human HSP60 (hHSP60) were measured in 48 patients with stable CAD and in 41 healthy controls by ELISA. CD14 genotype was determined by PCR and high-sensitivity C-reactive protein (hs-CRP) was measured. Results : Seropositivity to C. pneumoniae and H. pylori, and antibody titer to hHSP60 were not significantly associated with the presence of CAD. CD14 genotype distribution was 31 TT (35%), 43 CT (48%), and 15 CC (17%). To compare the response to the infectious organism and hHSP60, we divided study population into 3 groups; CAD patients with non-TT genotype (group I, n=30), CAD patients with TT genotype (group II, n=18), and normal controls (group III, n=41). Seropositivity to C. pneumoniae and H. pylori, and antibody titer to hHSP60 were not significantly different among 3 groups. Though hs-CRP level was significantly different among 3 groups, post-Hoc analysis showed that hs-CRP level was not significantly different between group I and group II (group I: 1.6[1.1-3.5] mg/L and group II: 0.35[0.1-2.0] mg/L). Conclusions : This study suggests that the inflammatory responses to infectious organisms and HSP do not differ according to the CD14 genotype in Koreans. 목적 : 만성적인 세균 감염이나 자가 면역 반응이 동맥경화와 연관되어 있다는 주장이 제기되어 왔다. CD14은 lipopolysaccharides (LPS)와 heat shock protein(HSP)의 수용체로 C(-260)→T 다형성이 관상동맥 질환의 위험과 관련되어 있다고 제안되어 왔다. 본 연구에서는 한국인에서 CD14 다형성에 따른 LPS와 HSP에 대한 반응성을 염증표지자를 측정하여 살펴보고자 하였다. 재료 및 방법 : 안정형 관상동맥 환자 48명과 정상 대조군 41명을 대상으로 Chlamydia pneumoniae, Helicobacter pylori 항체 및 인체 HSP60 (hHSP60) 항체 역가를 enzyme-linked immunosorbent assay (ELISA) 방법으로 측정하였다. CD14 유전자형은 중합효소연쇄반응을 이용하여 결정하였고 hs-CRP를 측정하였다. 결과 : C. pneumonias 및 H. pylori 항체 양성 여부 및 항체 역가, 그리고 hHSP60에 대한 항체 역가는 안정형 관상동맥 질환의 유무와 유의한 상관관계는 없었다. CD14 유전자형의 분포는 TT 30명(39%), CT 31명(40%), 그리고 CC 16명(21%)이었다. 관상동맥 질환 군에서 TT 유전자형은 38%, 대조군에서는 32%로 TT 유전자형과 관상동맥 질환의 유무와는 유의한 상관관계가 발견되지 않았다(P>0.05). CD14 유전자형에 따라 C. pneumonias와 H.pylori 감염 및 hHSP60에 따른 반응에 차이가 있는지 여 부를 알아보기 위해, 관상동맥 질환 군을 다시 TT 유전자형 군과 non-TT 유전자형 군으로 나누어, 전체적으로 세군에서 항체 양성률과 역가를 비교하였다(I군: CD14 TT 유전자형을 가진 안정형 관상동맥 환자, II군: CD14 TT 유전자형을 가진 안정형 관상동맥 환자, III군: 정상 대조군). 세 군에서 C. pneumonias와 H. pylori 항체 양성률 및 hHSP60 항체 역가에는 유의한 차이가 없었다. 세 군사이에 hs-CRP 값에 유의한 차이가 있었지만, post-Hoc분석에서 II군의 hs-CRP 값이 I군에 비해 유의하게 높지는 않았다(0.35 [0.1-2.0] mg/L in group II vs. 1.6 [1.1-3.5]mg/L in group I, P>0.05). 결론 : 본 연구는 한국인에서 CD14 유전자형에 따라 LPS나 HSP에 대한 반응이 유의하게 다르지 않음을 시사한다.

외과계 감염증에 대한 Sulperazon(Sulbactam/cefoperazone) 및 Cefoperazone의 임상효과 비교연구

박규주,노동영,김상준,권오중,정중기,홍인규 대한화학요법학회 1990 대한화학요법학회지 Vol.8 No.2

Despite recent advances in development of antibiotics and antiseptic techniques, infection still remains to be one of the major problems in the surgical field. Due to development of bacterial resistance to commonly used antibiotics, there is always a need to develop a new antimicrobial agent which would overcome such resistance. Sulperazon (Sulbactam/Cefoperazone) is a combination drug of potent β-lactamase inhigitor, sulbactam, and cefoperazone which has broad antibacterial spectrum, which was developed to combat against β-lactamase producing microorganisms. In an effort to evaluate the efficacy and safety of sulperazone, we have randomly divided 40 patients (12 with perforated appendicitis, 10 with peritionitis, 6 with GB empyema, 6 with periproctal abscess, 3 with wound infection, 1 liver abscess, 1 pancreatic abscess, and 1 acute cholangitis) into 2 groups (20 patients in each group). One group received daily dose of 2 to 3 grams of sulperazon and the other group received daily dose of 2 to 3 grams of cefoperazone. Following results were obtained : 1. Clinical effect of sulperazon was cure in 16 patients (80%), improvement in 3 patients (15%), compaired to cure in 14 patients (70%), improvement in 4 patients (20%) for the cefoperazone group. 2. Using disc diffusion method, sulperazon was sensitive to all of the isolated microorganisms except β-hemolytic streptococci, which was moderately sensitive. Cefoperazone was sensitive to only E. coli, Pseudomonas aeruginosa and Serratia. 3. Microbiological effect of sulperazon was eradication of offending microorganisms in 16 patients (80%), compared to 14 patients (70%) in Cefoperazone group. 4. Overall clinical efficacy of sulperazon was 95%, compared to 80% for cefoperazone. 5. Adverse effects due to sulperazon was nausea and diarrhea which occurred in 1 patient respectively. 2 patients receiving cefoperazone experienced diarrhea. It can be concluded that sulperazon is a safe and effective antibiotic agent which can be used in surgical infection patients.

工業敎育大學 敎育改善에 관한 硏究(Ⅲ)

宋周鎬,李昌岬,洪元杓,孟琦錫,任洪彬,李廷玟,李載元,李來烈,權五憲,金振淳,李文洙 충남대학교 공업교육연구소 1982 論文集 Vol.5 No.1

This paper aims at providing a concrete plan to improve technical and vocational teacher education in the College of Industrial Education of Chungnam National University. It is intended to propose a practical four-year regular and short-term course. Also, the estimated required facilities is included in this study as well as their management. The main conclusions and recommendations are summarized as follows; 1) The numbers of students enrollment should be reduced to 220 students which is the approximate number of future demand. 2) In order to offer to the students a broader education and to cope with the increase/decrease in demand of technical and vocational teacher within a specific field, the 8 department existing at the present (Department of Architecture Engineering Education, Civil Eng. Educ., Metallurgical Eng. Educ., Mechanical Eng. .Educ., Electrical Eng. Educ., Electronic Eng. Educ., Industrial Chemistry Educ. and Industrial Technology Educ.) would be combined into 5 (Department of Construction Engineering Education, Mechanical Eng. Educ., Electrical Eng. Educ., Industrial Chemistry Educ. and Industrial Technology Educ.). 3) The short-term course program is recommened to provide additional training and education to those candidates who already have experience in technical fields to meet an occasional demand. 4) It is necessary to add the Teaching Profession Section in the administrative organization of the College.

소금 종류 및 농도에 따른 김치 효모균의 생육특성

한영숙,권민경,현영희,송주은,오지영 동아시아식생활학회 2001 동아시아식생활학회지 Vol.11 No.5

Effects of various types of salts (commercial low salt, sea salt, refined salt, and bamboo salt) and concentrations (0, 3.0 and 5.0%) on the growth of yeasts isolated from Kimchi were investigated. The isolated yeasts used in the study are as follows: Saccharomyces cerevisiae. Sporobolomyces albo-rubescens, Issatchenkia orientalis, Cryptococcus luteolous, Ustilago maydis. Candida humilis, Pichia onychis, Cadida nitratophila, and Pichia jadinii. The growths of the yeasts were inhibited against each salt concentration. The growths of Candida sp. isolated from the later stage of fermentation was strongly inhibited against 5% concentration of salt. On the other hand the induction phase of Issatchenkia orientalis isolated at the early stage of fermentation was the quickest among all the tested yeasts. Among the salts. bamoo salt was found to be strongest inhibitor of, the growth of yeasts.