정체류에서 피막전극에 대한 산소의 전달현상

이창우,장호남 한국화학공학회 1979 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.17 No.2

막을 씌운 전극을 사용하여 산소농도를 측정함에 있어서 외부에 stagnation flow를 형성시켰을 때 전류반응을 고찰하였다. stagnation flow에서 산소의 전달현상을 해석하기 위해 몇가지 가정하에 수학적 모델을 세우고 이 결과를 실험치와 비교하였다. 폴리에칠렌 막과 백금전극을 사용한 수용액에의 실험에서는 계산된 유체역학적 boundary layer의 두께가 전극의 반경보다 작거나 거의 같을 때는 유속의 변화에 대한 실험결과는 이론치와 잘 일치한다. 그러나 이보다 커지게 되면 이론치와 실험결과는 많은 차이가 있었으며 이는 일차원적 모델에서 무시되었던 반경방향의 확산이 점차적으로 중요해지기 때문으로 추측된다. 막의 두께가 두꺼워짐에 따라 수용액에서 유체역학적 상황의 변화에 따른 전류응답이 점차적으로 덜 민감해 지는 것을 알 수 있었다. The current response of a membrane covered-electrode with respect to the fluid motion in stagnation flow was investigated in this study. The mathematical model was set up to analyze oxygen transport in this flow regime. The current predicted by the model was compared with the results of the experiments performed using polyethylene film and platinum cathode. One dimensional model was in good agreement with the experimental results when the thickness of hydrodynamic boundary layer was smaller than or comparable to the radius of the electrode, but it did not agree well when the thickness exceeded the radius of the electrode. This may be due to the reason that the radial diffusion term neglected in one dimensional model becomes important as well as the axial diffusion term. It appeared that the current response became less sensitive to the hydrodynamics of the outside of membrane as the thickness of membrane increased.

좌표자료를 이용한 산사태 위험등급의 검증

이창우,윤호중,김재헌,정용호 한국임학회 2006 한국임학회 정기학술발표논문집 Vol.2006 No.-

화학기상응축 공정을 이용한 중공 나노입자의 합성

이창우,김우병,이재성 한국분말야금학회 2005 한국분말야금학회 학술대회논문집 Vol.2005 No.1

Properdin의 생물학적 역할에 관한 실험 : 수포성 유천포창 환자의 혈청을 이용한 in vitro 보체 면역형광검사 In vitro complement immunofluorescent study using sera of the patients with bullous pemphigoid

이창우,김수남 大韓免疫學會 1981 大韓免疫學會誌 Vol.3 No.1

The human complement system is composed of at least 19 distinct serum proteins, when activated, generate a number of biologically active substances those can contribute in host defence mechanism and also play as mediators of inflammatory reaction. This complement system consist of four functional divisions, the classic and alternate pathways, a single amplification loop that is recruited by each activating pathway and a terminal common pathway of which the activating and amplification sequence are directed. Activation of the classic pathway occurs by immune complex usually composed of immunoglobulin (Ig) G or M, involves activation of Clq with subsequent cleavage of C4 and C2 to form C42, the classic C3 convertase. Activation of the alternate pathway occurs by immune complex usually composed of IgE, or with certain microbial polysaccharide, which interact with Factor D, Factor B and C3 to achieve initial C3 activating pathway. In the amplification loop activation, C3b generated by either pathway, interact further with Factor D and Facto' B to form the amplification C3 convertase, Cb3B. This C3bB complex in amplification loop is labile because of irreversible decay by regulatory proteins, but in the presence of properdin which can bind to C3b then stablize the convertase forming C3bBP and increase its half-life, thereby profoundly augment the amplification of C3 cleavage and to some extent protect against regulatory proteins, C3bINA and 13IH globulin. This complement system has been implicated principally in the pathogenesis of bullous pemphigoid, a subepidermal blistering skin disease characterized immunologically by the presence of autoantibody to the skin basement membrane zone. Many research workers demonstrated the deposition of classic pathway components (Clq and C4) and amplification loop components (Factor B and properdin) along the basement membrane zone in addition to IgG and C3 in the lesional skin of the patients with bullous pemphigoid. It has been believed u aiiu NlvyGi uut occurs via the amplification C3 following generation of C3b by the classic pathway convertase To demonstrate the biologic role of properdin on activation. n amplification examined the amounts of C3 deposit along the basement membrane zone by3buconvertase, lious em author antibody using two different complement sources, p p~goid serum serum devoid of properdin prepared according to Todd's procedure, b and oocom ement immunofluorescence method. Y i n vitro complement In this study four patients with bullous iirimuno this study diagnosed histopathologically and y, were selected. All these patients had anti basement membrane zone antibody titers of 1:160 or greater, and demonstrated heavy deposit of C3 along the basemen membrane zone by direct immunofluorescent test. t The intensities of C3 deposition when using each different complement source were recognized according to the following criteria: weak linear or discontinuous weak linear fluorescence ++ ; easily recognizable, apparent fluorescence ; strong band-like or lumpy fluorescence Control studies were also accomplished in every case and the results were as follows: 1) All four serum samples yielded positive when normal human serum were used as complement source. When the of in intensity properdin was substituted as the complement source, the intensities of C3 f pserum devo of roperdin was sudiminished to + in all cases. 2) All negative control studies showed negative fluorescence reactions and positive control studies showed positive fluorescence reactions in every time of the experiment. This in vitro study confirmed others' experimental studies on the biologic role of properdin as the stabilizer of C3 convertase in the amplification loop.

A.1 : 국방품질(1) : A.1.3 ; 방산업체 품질수준 평가

이창우,김정호 한국품질경영학회 2011 한국품질경영학회 학술대회 Vol.2011 No.1

In this paper, we introduce the Quality Performance Index in defense industry. It is the enhanced plan to achieve the continuous inspection and improvement of process for the purpose of process efficiency in production. The index is evaluated by a quality assurance agent, Defense agency for Technology and Quality once a year. To compute the QPI which is defined as the rating system based on the objective data of defense industry that can be obtained through quality management activities of DTAQ, we consider four indices about defense quality management system. We derive the rating system using distribution function for each quantitative/qualitative index. We propose the construction of QPI, details of activities, rating system, indicators calculation to perform this research.

집단 정서지능의 측정도구 타당성 연구

이창우,윤혜영 한국항공경영학회 2011 한국항공경영학회 춘계학술대회 Vol.2011 No.-

Efficient Conversion of DCT Coefficients to H.264 Transform Coefficients Using Lapped Transforms

이창우,Lee, Chang-Woo The Korea Institute of Information and Commucation 2007 韓國通信學會論文誌 Vol.32 No.7c

In order to convert MPEG-2 into H.264 format in ubiquitous communication environments, the efficient conversion of the discrete cosine transform (DCT) coefficients to H.264 transform coefficients is essential. In this paper, two efficient conversion systems are proposed. The proposed systems are composed of two parts. In the first part, the DCT coefficients are denoised using the lapped transform (LT) to reduce the quantization noises and blocking effects. In the second part, the denoised DCT coefficients are converted into the integer transform (IT) coefficients of H.264. Simulation results show that the proposed methods provide visually fine images. Moreover, the computational complexity of the proposed method is reduced compared with the conventional method, since the number of the DCT coefficients, which should be converted, is reduced in the first part.

Low Complexity Decoder for Space-Time Turbo Codes

이창우,Lee Chang-Woo The Korea Institute of Information and Commucation 2006 韓國通信學會論文誌 Vol.31 No.4c

By combining the space-time diversity technique and iterative turbo codes, space-time turbo codes(STTCS) are able to provide powerful error correction capability. However, the multi-path transmission and iterative decoding structure of STTCS make the decoder very complex. In this paper, we propose a low complexity decoder, which can be used to decode STTCS as well as general iterative codes such as turbo codes. The efficient implementation of the backward recursion and the log-likelihood ratio(LLR) update in the proposed algorithm improves the computational efficiency. In addition, if we approximate the calculation of the joint LLR by using the approximate ratio(AR) algorithm, the computational complexity can be reduced even further. A complexity analysis and computer simulations over the Rayleigh fading channel show that the proposed algorithm necessitates less than 40% of the additions required by the conventional Max-Log-MAP algorithm, while providing the same overall performance.

저압 초음파 분무 공정을 이용한 γ-Fe₂O₃ 나노입자의 합성

이창우,김순길,좌용호,이재성,Lee, Chang-Woo,Kim, Soon-Gil,Choa, Yong-Ho,Lee, Jai-Sung 한국분말야금학회 2007 한국분말재료학회지 (KPMI) Vol.14 No.1

This study was focused on the optimization of low-pressure ultrasonic spraying process for synthesis of pure ${\gamma}-Fe_2O_3$ nanoparticles. As process variables, pressure in the reactor, precursor concentration, and reaction temperature were changed in order to control the chemical and microstructural properties of iron oxide nanoparticles including crystal phase, mean particle size and particle size distribution. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies revealed that pure ${\gamma}-Fe_2O_3$ nanoparticles with narrow particle size distribution of 5-15 nm were successfully synthesized from iron pentacarbonyl ($Fe(CO)_{5}$) in hexane under 30 mbar with precursor concentrations of 0.1M and 0.2M, at temperatures over $800^{\circ}C$. Also magnetic properties, coercivity ($H_c$) and saturation magnetization ($M_s$) were reported in terms of the microstructure of particles based on the results from vibration sampling magnetometer (VSM).

Proteomic analysis of human serum from patients with temporal lobe epilepsy

이창우,유승택,최하영,고은정,곽용근 대한소아청소년과학회 2009 Clinical and Experimental Pediatrics (CEP) Vol.52 No.5

Purpose : Epilepsy affects more than 0.5% of the world's population. It has a large genetic component and is caused by electrical hyperexcitability in the central nervous system. Despite its prevalence, the disease lacks definitive diagnostic serological biomarkers. To identify potential biomarkers for epilepsy by a convenient method, we analyzed the expression of serum proteins, reflecting alterations in the patient's proteomes. Methods : We compared two-dimensional electrophoretic band patterns of human sera from eight patients with temporal lobe epilepsy (TLE) with those of eight control subjects. The differentially expressed bands were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and electrospray ionization quadrupole time-of-flight mass spectrometry. Results : Twelve proteins were differentially expressed in the TLE group, of which 6 were identified. Expression of haptoglobin Hp2, PRO2675, immunoglobulin heavy chain constant region gamma 2, an unnamed protein, and three unidentified proteins were upregulated in serum from the patients with TLE, whereas those of major histocompatibility complex (MHC) class I antigen, plasma retinol-binding protein precursor, and three unidentified proteins were downregulated in these patients. After resection of the epileptogenic zone, the expressions of MHC class I antigen, immunoglobulin heavy chain constant region gamma 2, two of the downregulated unidentified proteins, and one of the upregulated unidentified proteins returned to the normal range. Conclusion : The 12 serum proteins in this study are potentially useful biomarkers for the diagnosis and monitoring of TLE. Purpose : Epilepsy affects more than 0.5% of the world's population. It has a large genetic component and is caused by electrical hyperexcitability in the central nervous system. Despite its prevalence, the disease lacks definitive diagnostic serological biomarkers. To identify potential biomarkers for epilepsy by a convenient method, we analyzed the expression of serum proteins, reflecting alterations in the patient's proteomes. Methods : We compared two-dimensional electrophoretic band patterns of human sera from eight patients with temporal lobe epilepsy (TLE) with those of eight control subjects. The differentially expressed bands were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and electrospray ionization quadrupole time-of-flight mass spectrometry. Results : Twelve proteins were differentially expressed in the TLE group, of which 6 were identified. Expression of haptoglobin Hp2, PRO2675, immunoglobulin heavy chain constant region gamma 2, an unnamed protein, and three unidentified proteins were upregulated in serum from the patients with TLE, whereas those of major histocompatibility complex (MHC) class I antigen, plasma retinol-binding protein precursor, and three unidentified proteins were downregulated in these patients. After resection of the epileptogenic zone, the expressions of MHC class I antigen, immunoglobulin heavy chain constant region gamma 2, two of the downregulated unidentified proteins, and one of the upregulated unidentified proteins returned to the normal range. Conclusion : The 12 serum proteins in this study are potentially useful biomarkers for the diagnosis and monitoring of TLE.