외부 강선 보강용 정착장치의 비교 분석 연구

학위논문(석사)--아주대학교 대학원 :토목공학과,2003Maste

Anti-phishing relative one-time password systems

Thesis(masters) --서울대학교 대학원 :전기. 컴퓨터공학부,2008.2Maste

The noise reduction technique from the partial discharge signals

Maste

Phase Equilibria and Thermodynamics of the CaO–Al2O3–CaS and the CaO–SiO2–CaS Oxysulfide Systems

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Microbial Conversion of Cholesterol to 4-Androstene-3,17-dione by Intermittent Addition of Substrate

Cholesterol로부터 미생물전환 방법에 의한 4-androstene-3,17-dione(AD)의 생성에 대해 연구를 수행했다. 발효액중에 cholesterol의 용해도를 증가시키기 위해 ethanol을 용매로 사용하였는데, ethanol 농도가 2%(v/v)까지는 세균성장이 크게 저해되지 않았다. 미생물전환은 pH를 7.0으로 조절하고, 초기대수 증식기에 cholesterol을 첨가했을 때 효율적으로 AD가 생성되었다. AD 생성을 높이기 위해 cholesterol 첨가방법을 여러 가지로 변환시켰다. 즉, 최종 cholesterol 농도를 0.1% 하여 ethanol에 녹여 간헐적으로 첨가했을 때 가장 높은 수율을 얻었다. Cholesterol을 세번(전체 3g/ℓ) 첨가했을 때 최종 전환수율이 65%에 도달한 반면, 같은 양의 cholesterol (3g/ℓ)을 한번에 넣었을 때 40%의 생성수율을 얻었다

선도 국가 정보를 이용한 신제품 확산모형

학위논문(석사) - 한국과학기술원 : 경영정책학과, 1995.2, [ iii, 64 p. ]To refine the Bass model, most researchers have implicitly assumed that a sufficiently long time series of data is available. However, managers have not enough time to collect a sufficiently long time series of data for predicting the diffusion rates. Therefore, managers cannot help using their intuitions or simple heuristics that lack logical justifications. We develop a diffusion framework by postulating that the vectors of coefficients representing the impact of country-specific (CS) and product-specific (PS) variables in a leading country are equal to those of a lagging country. The model allows us to predict the diffusion patterns of the new products in lagging countries when few or no data points are available. Furthermore, by relating the parameter estimates to various dimensions of CS and PS variables, this model allows the diffusion parameters to differ systematically across countries as well as along time periods for an innovation in a country.한국과학기술원 : 경영정책학과

Enhancement of Biotransformation Yield in 11α-Hydroxylation of Progesterone by Continuous Addition of the Substrate

Biotransformation of progesterone to 11 α -hydroxyprogesterone by growing cells of Rhizopus nigricans was investigated. As the concentration of progesterone increased, the specific growth rate of R. nigricans decreased linearly, and consequently the conversion yield lowered. The hyphae of the microorganism were observed to become thicker, shorter, and more densely branched at high concentrations of progesterone. In order to improve the process productivity, biotransformation was conducted with continuous addition of progesterone. When the substrate was added continuously at a rate of 0.86 g/hr for 30 hrs, overall conversion yield reached upto 56% while a single addition of the same amount of progesterone yielded about 40% eonversion. When additional feeding of glucose was carried out upon its depletion, an improved broconversion yield upto 68% was obtained

penicillin amidohydrolase for production of 6-anmino-penicillanic acid

학위논문(석사) - 한국과학기술원 : 생물공학과, 1976.2, [ [iii], [69] p. ]Penicillin amidohydrolase, an enzyme which hydrolyzes benzylpenicillin to give 6-Aminopenicillanic acid and phenylacetic acid, was produced by using \mbox{\underline{Bacillus}} \mbox{\underline{megaterium}} culture. Production of the enzyme from the strain was increased 20 fold by modification of culture medium and the fermentation method. Larger amount of phenyl acetic acid than reported by other investigators was added to the actively growing cell to induce the maximum production of the enzyme. When casitone-containing medium was used, the highest enzyme yield was obtained. Optimal temperature and PH for the activity of bentonite-immobilized penicillin amidohydrolase was 40-45℃ and 8-9, respectively. The performance of two-stage continuous stirred tank enzyme reactor (CSTR) system was evaluated from the results of computer simulation study of the system. The productivity of the reactor system using immobilized enzyme was much higher than using soluble enzyme, which was mainly due to the higher value of product inhibition constant of immobillized enzyme than that of soluble enzyme. The productivity obtained with the two-stage CSTR system was found to be 9.5 m mole of 6-APA per liter of reactor working volume per hour and it was 50% higher than that obtained with the single stage system under the given operational condition. The optical feed concentration of substrate that give the maximum productivity was found to be 0.18 M for 95% conversion requirement and corresponding the first and second stage space time were 10 hours and 8 hours, respectively.한국과학기술원 : 생물공학과

Experiment and thermodynamic modeling of CaO-(Al2O3,SiO2)-CaS oxysul랴de system and nozzle clogging prevention in Al-killed steel

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