고주파 표면경화강의 회전굽힘피로강도에 미치는 영향에 관한 연구

이치우,정상영 경남대학교 신소재연구소 1994 論文集 Vol.4 No.-

기계 구조용강 SM 45C을 고주파 표면 경화처리를 하여 회전 굽힘 피로시험하여 경도 분포, 조직, 피로강도 곡선 및 파괴 관찰을 하여 피로 파단점 N₁=10⁴사이클에서 표면기점파괴와 내부기점파괴가 나타나며 이는 피로 파괴가 시작되는 경계층 경계부에서는 마르텐사이트에 비해 상대적으로 연질 페라이트가 나타나고 이것이 파괴의 기점이 되며 모재의 열처리 영향에 EK라 경화층에서는 입계 파괴에서 연성파괴로 비경화층에서는 벽개 파괴로 파면 형태가 달라짐을 알 수가 있었다. Hardness, microstructure, fatigue strength curve and fracture types are observed by using the rotating-bending fatigue testing with the high frequeney surface hardening treated of structural steel SM 45C, and the results are appeared to the surface and internal fracture origin types at the fatigue life N,=l0⁴cycle. On the separatim parts of boundary layer occurring the fatigue fracture. It is given the soft-ferrite compare to the martensite, and fathermore could be predicted the different fracture types from the grain boundary fracture to ductile fracture on the hardened layer and to cleavage fracture on the non- hardened layer, by affecting the heat treatment of matrix.

Newton-Raphson Method와 Matrix를 이용한 고차방정식의 인수분해 기법

장영우,황치정 충남대학교 기초과학연구소 1995 忠南科學硏究誌 Vol.22 No.1

Application of Newton-Raphson iteration, partial differentiation and linear algebra in factoring both real and complex coefficient polynomials is presented. When factorizating complex polynomials, it is shown that calculations can be performed in real arithmetic only. Complex cases expand the matrix size by a factor of two due to the real-numbers-only computation. For complex cases with large matrices, the method to calculate inverse matrix and factor polynomials using quarter matrices is suggested.

비선형모델의 선형화 변환 기법

장영우,황치정 충남대학교 기초과학연구소 1995 忠南科學硏究誌 Vol.22 No.1

For analyzing systems of multi-variate nonlinear equations, the linearized modelling techniques are expedited. The technique applies Newton-Raphson iteration, partial differentiation and matrix operation providing solvable solutions to complicated problems. Practical application examples are given in; determining the zero point of functions, determining maximum (or minimum) point of functions, nonlinear regression analysis, and solving complex coefficient polynomials. Merits and demerits of linearized modelling techniques are also discussed.

연소진동의 발생과 그 진단 기술에 관한 연구

양영준,이치우 진주산업대학교 산업과학기술연구소 2007 산업과학기술연구소보 Vol.- No.14

Self-excited combustion oscillation has been occurred many industrial facilities, for example, such as boilers, gas turbines and various engines. The generation of self-excited combustion oscillation often leads to system destruction as well as environmental problem like noise. In order to predict the onset of self-excited combustion oscillation, detecting method of self-excited combustion oscillation was experimentally examined. For this purpose, the unique measures, which were based on the careful statistics of fluctuating properties in flames, were performed using pressure transducer and CCD camera.

양극성 장애와 Monocyte Chemoattractant Protein-1 유전자 다형성

배치운,김태석,장우영,김정진,이창욱,이수정,전태연,이철,백인호 大韓神經精神醫學會 2004 신경정신의학 Vol.43 No.5

Objectives : Several studies suggested that cytokines could be involved in the pathogenesis of mood disorders, while data for bipolar disorder is relatively deficient (BD). BD, Knowned to have a inherited tendency, has been considered to be related with T-helper cell system. This study was designed to investigate the association between polymorphism of monocyte chemoattractant protein-1 (MCP1) gene at promoter-2518 and BD. Methods : Patients with BD (n=92) in accordance with DSM-FV criteria and control subjects (n=114) participated in this study. DNA was extracted from whole blood and the MCP-1 gene promoter region was amplified by polymerase chain reaction-based method. Results : Genotype and allele distributions in patients with BD were not different from those of control subjects (p=0.587 ; p=0.384). Genotype and allele distributions in accordance to presence or absence of suicide attempt (p=0.423), family history (p=0.733) and psychotic feature (p=0.436) were not different between the two groups. Conclusion : Present study suggests that the MCP1 promoter -2518 polymorphism may not affect the susceptibility and clinical diversity of the development of BD.

급성 신우신염이 선행된 Escherichia coli 농흉 1예

차치운,조준형,김미진,오윤정,연재우,이성규,오미정,채지영,김수연 대한감염학회 2009 감염과 화학요법 Vol.41 No.5

We experienced a case of acute pyelonephritis which progressed to Escherichia coli bacteremia and later complicated by empyema in a 65-year-old female. She was successfully treated with intravenous antibiotic therapy and percutaneous drainage of empyema.

연속주조내 용융금속 유동장의 수학적 모델링(Ⅰ)

이치우,이성우,정상영 경남대학교 신소재연구소 1992 論文集 Vol.2 No.-

연속주조 턴디쉬 및 신주조기술인 쌍롤박판 주조기내의 응용금속장을 예측하는 수학적 모델링을 개발하였다. 그 응용금속유동장을 위한 수학적 구성식은 난류성분을 표현하는 난류 Navier-Stock식을 근거하고 K-ε난류방정식과 함께 유동장예측 및 난류성분의 결과를 제시하였다. A mathematical modelling has been developed for describing the flowfilds of molten metal in the tundish and the twin-roller procss of continuous casting. The formulation of the tundish and the twin-roll process were dased on the turbulent Navies-Stokes equation in which allowance was made for the spatially distributed turbulent velocity field of molten metal. The calculation of turbulent properites using the two equation K-E turbulence model have been applied, and predicted results are presented.

Lidocaine, Thrombin, Epinephrine 의 항균효과

김진우,이동건,전혜선,김승준,김석찬,안중현,김치홍,권순석,김영균,김관형,문화식,신완식,송정섭,박성학 대한감염학회 2005 감염과 화학요법 Vol.37 No.6

목적 : 기관지내시경 검사에서 흔히 사용되는 국소마취제인 lidocaine과 내시경시 지혈목적으로 사용되는 thrombin과 epinephrine이 각종 균주에 미치는 항균효과에 대해 알아보고자 하였다. 재료 및 방법 : 균주는 가톨릭대학교 성모병원에서 2004년 3월부터 2004년 9월까지 임상검체 에서 동정된 S. aureus, S. pneumoniae, K. pneumoniae, P. aeruginosa 각각 42, 42, 42, 43주를 대상으로 하였다. Lidocaine, thrombin, epinephrine 감수성 검사는 National Committee for Clinical Laboratory Standards (NCCLS, 2002)의 기준에 따랐다. 결과 : Lidocaine은 S. aureus, S. pneumoniae, P. aeruginosa에서 MIC_(50), MIC_(90) 모두 20,000 ㎍/mL 이었다. K. pneumoniae는 각각 10,000 ㎍/mL이었다. Thrombin은 S. aureus와 P. aeruginosa에서 MIC50 500 lU/mL 과 MIC_(90) 500 IU/mL 이상이었고, K. pneumoniae에서는 MIC_(50)과 MIC_(90)이 모두 500 lU/mL이상이었으나 S. pneumoniae에서는 MIC_(50)과 MIC_(90)은 125 IU/mL이었다. Epinephrine은 K. pneumoniae, S. pneumoniae에 대한 MIC_(50), MIC_(90)가 모두 >500 ㎍/mL이었고, S. aureus와 P. aeruginosa에 대한 MIC_(50), MIC_(90)가 모두 500 ㎍/mL이었다. 결론 : 기관지 내시경 검사에서 흔히 쓰이는 lidocaine, thrombin, epinephrine 등의 약제들이 호흡기 질환의 흔한 병원균인 S. aureus, S. pneumoniae, K. pneumoniae, P. aeruginosa 균주들에 대해 항균 효과가 있을 수 있어 세균배양검사에 영향을 미칠 수 있겠다. Background : We performed this stody to find out about antimicrobial effect of lidocaine which is commonly used local anesthetic, and thrombin and epinephrine used for hemostasis during bronchoscopic procedures. Materials and Methods : The microorganisms that were cultured from specimens obtained during bronchoscopy were Staphylococcus aureus (n=42), Streptococcus pneumoniae (n=42), Klebsiella pneumoniae (n=42), and Pseudomonas aeruginosa (n=43) collected from St. Mary's Hospital, from March to Sep 2004 were used for susceptibity testing. Susceptibility to lidocaine, thrombin, and epinephrine were tested according to the National Committee for Clinical Laboratory Standards. Result : MIC_(50) and MIC_(90) of lidocaine for S. aureus, S. pneumoniae, P. aeruginosa were all 20,000 ㎍/mL and that for K. pneumoniae were 10,000 ㎍/mL. MIC_(50) and MIC_(90) of thrombin for both S. aureus and P. aeruginosa was 500 IU/mL and above 500 IU/mL, respectively; that for K. pneumoniae were all above 500 IU/mL and for S. pneumoniae they were 125 IU/mL, MIC_(50) and MIC_(90) of epinephrine for K. pneumoniae and S. pneumoniae were above 500 ㎍/mL; that for S. aureus and P. aeruginosa were 500 ㎍/mL. Conclusion : We observed possible antimicrobial effect of lidocaine, thrombin, and epinephrine in vitro against pathogens such as S. aureus, S. pneumoniae, K. pneumoniae, P. aeruginosa, which are common respiratory microorganisms. The use of these agants could affect the result of bacterial culture.

Aromatic hydrocabon 분해세균의 검출과 그 plasmid 유전자의 특성

김치경, 김종우, 김영창, 민태익 忠北大學校 遺傳工學硏究所 1987 遺傳工學硏究 Vol.1 No.1

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Gauss-Seidel 계의 수렴조건및 해석에 관한 고찰

장영우,황치정 충남대학교 기초과학연구소 1995 忠南科學硏究誌 Vol.22 No.1

Gauss-Seidel iteration method can be used in analyzing multi-variate linear systems of equations. This method provides fast algorithm when convergence conditions are satisfied. But, normally it is tricky and difficult to have satisfactory convergence conditions. This paper researches possibilities of applying Gauss-Seidel method to nonlinear cases as well as linear cases. Simple criteria for finding convergence conditions are presented. Given the difficulty of meeting convergence conditions, a linearized approach is suggested for solving most nonlinear systems derived from Gauss-Seidel forms.