• 제목/요약/키워드: growth process

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신경망과 유전 알고리즘을 이용한 광소자용 ZnO 박막 특성 공정 모델링 및 최적화 (Process Modeling and Optimization for Characteristics of ZnO Thin Films using Neural Networks and Genetic Algorithms)

  • 고영돈;강홍성;정민창;이상렬;명재민;윤일구
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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    • pp.33-36
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    • 2004
  • The process modeling for the growth rate in pulsed laser deposition(PLD)-grown ZnO thin films is investigated using neural networks(NNets) and the process recipes is optimized via genetic algorithms(GAs). D-optimal design is carried out and the growth rate is characterized by NNets based on the back-propagation(BP) algorithm. GAs is then used to search the desired recipes for the desired growth rate. The statistical analysis is used to verify the fitness of the nonlinear process model. This process modeling and optimization algorithms can explain the characteristics of the desired responses varying with process conditions.

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ZnO 세라믹스 거대입성장 (Abnormal grain growth of ZnO ceramics)

  • 김영정
    • 한국결정성장학회지
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    • 제29권6호
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    • pp.251-256
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    • 2019
  • ZnO를 통상적인 소결온도 이상의 온도 1385℃에서 소결하는 과정에서 mm 크기로 거대 성장된 입자를 갖는 세라믹스를 제조하였다. 1400℃에서 8시간 소결하는 경우 성장에 참여하지 않은 입자의 크기는 30~40 ㎛이고 거대 성장된 입자는 1,000 ㎛에 달하여 부피비 최소 10,000배 이상의 급속한 성장이 이루어졌다. 이러한 급속한 성장의 원인으로 일차 입자 크기분포, 성형압 불균일 또는 불순물의 합입등을 고려하였으며, 이들 중 일차입자 크기 분포일 것으로 추정되나 확실한 증거를 확보하지 못하였다. 미세구조 관찰을 통해 거대입자 성장은 주변의 입자를 통째로 합치는 과정을 통해 성장하는 것으로 추정된다.

Milk-Derived Growth factors as Neutraceuticals

  • Kang, Shin-Ho
    • Journal of Dairy Science and Biotechnology
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    • 제25권1호
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    • pp.27-31
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    • 2007
  • Colostrum has lots of bioactive components and many growth factors including insulin-like growth factors, transforming growth factors and epidermal growth factor. Colostrum and milk derived growth factors widely mediate the growth of overall development and could be used as treatment of gastrointestinal disorder, wound repair process, bioacrivity in the neonatal GI tract and induction of oral tolerance. It is possible that milk derived growth factors as potential neutraceuticals for the specific consumers may have a great role in future food industry.

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Transprt Phenomena in Bulk Crystal Growth Processes

  • Lan, C.W.
    • 한국결정성장학회:학술대회논문집
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    • 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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    • pp.29-33
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    • 1998
  • Transport phenomena paly an inmportant role in bulk crystal growth processes. During crystal growth, the control of the growth front and the dopant concentration is crucial to crystal quality. The growth feasibility in thus determined by the heat transfer controlling the interface convexity and by the mass transfer controlling the constitutional supercooling. Through numerical modeling, a thorough understanding of the growth processes is possible, which in turn is a key to process improvenment. In this paper, we will summarize some work dine in my laboratory, both numerical and experimental, to illustrate the importance of understanding the transport phenomena during crystal growth processes.

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The Effect of Light on Champagne Yeast Cell Growth and Ethanol Production Under Variable pH Conditions

  • Collins, Paul C.;Schnelle, Karl B.;Malaney, Jr.George W.;Tanner, Robert D.
    • KSBB Journal
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    • 제6권2호
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    • pp.189-194
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    • 1991
  • The effect of wtlitc light on unaeraten growth of Baker's yeast and the accompanying ethanol production has been studied in a batch process at 27$^{\circ}C$. Over the 80-hour period of the Champagne yeast process without pH control, the cull growth was inhibited by the fluorescent light. Another observed difference between the runs is that the drop and subsequent rise in redox potential occurred much sooner in the fermentation with light than in the fermentation without light. This preliminary study indicated that ethanol production could be enhanced by light as the cell concentration is repressed. The possible pathway, shift of the sugar substrate toward ethanol and away from cells was manifested by another difference as well. As observed under the microscope, many of the yeast cells grown under light budded without dividing by the normal fission process as they did in the dark. Furthermore, the undivided and branched (light grown) cell did not agglutinate at the end of the fermentation process as did the distinct spherical (dark grown) cells.

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Waspaloy의 열간 단조 공정중 재결정 거동과 결정립 성장에 대한 유한요소해석 (Computer Simulation of Recrystallization and Grain Growth during Hot Forging Process of Waspaloy)

  • 강경필;이경훈;이승욱
    • 소성∙가공
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    • 제17권2호
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    • pp.113-116
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    • 2008
  • Computer simulation of microstructure evolution during hot forging process is of great interest in recent years. Recrystallization model and grain growth model which use a phenomenological approach were summarized. The upsetting and cogging processes of waspaloy were simulated using $DEFORM^{TM}$ and the change in grain size were investigated in each deformation procedure.

동시 스퍼터법으로 제작한 Bi 초전도 박막의 성장 모델 (Growth Model of Bi-Superconducting Thin Film Fabricated by Co-sputtering Method)

  • Chun, Min-Woo;Park, Yong-Pil
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2002년도 추계종합학술대회
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    • pp.796-799
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    • 2002
  • BSCCO thin films are fabricated via a co-deposition process at an ultra-low growth rate using ion beam sputtering. The sticking coefficient of Bi element exhibits a characteristic temperature dependence. This temperature dependence of the sticking coefficient was explained consistently on the basis of the evaporation and sublimation processes of Bi$_2$O$_3$.

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경립종 옥수수의 성장과정중 비극성 지질의 지방산 변화 (Change of Fatty Acid of Non-Polar Lipid in Flint Corn During the Growth Process)

  • 박창일;김덕진;김용수
    • 한국식품영양과학회지
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    • 제23권5호
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    • pp.811-815
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    • 1994
  • In this study the quantity and the ratio of saturated and unsaturated fatty acids were investigated with using gas chromatography after non-polar lipid of the flint corn in the growing period was extracted with the solution of chloroform : methanol (2 : 1) and then separated by the SACC method. Neutral lipid was separated into monoglyceride(MG), 1, 3-diglyceride (1, 3-DG) , free fatty acid (FFA) , triglyceride (TG), cholesteryl ester (CE). Fatty acid of each spot was mainly composed of linoleic , oleic and palmitic acids. Lonolieic acid decreased in MG(54.5-51.4%), CE(31.3-28.9%) but increased ini TG(57.2-63.8%) during growth process. Olec acid increased in MG(25.7-29.3%), 1, 3-DG(24.7-28.9%), CE(16.7-19.9%) but decreased in TG28.6-23.1%). Palmitic acid decreased in MG(12.8-11.5%), FFA(25.7-24.1%), TG(10.4-9.3%) but increased in CE(26.4-31.5%) during a growth process. The ratio of unsaturated to saturated fatty acid in TG(7.01-7.84%) was higher in five spots of neutral lipid and in 1, 3-DG(4.61-4.16%) decreased growth process but increased in MG(5.06-5.60%), TG(7.01-7.84%).

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Comparison of OECD Nations through a Comprehensive Evaluation Index for Low-Carbon Green Growth

  • Yoo, Eui Sun;Park, Sung Hyun;Lee, Min Hyung
    • STI Policy Review
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    • 제1권2호
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    • pp.51-68
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    • 2010
  • This paper compares OECD nations by developing a comprehensive evaluation index that examines the efforts and achievements of countries toward Low-Carbon Green Growth. The input-process-output of a Low-Carbon Society system is in dynamic competition with that of a High-Carbon Society system. The model used in this study of the comprehensive evaluation index for Low-Carbon Green Growth was comprised of Large indices such as Input, Process, and Output. The Input and Output consisted of 'Social-economic' and 'Physical-ecological' Middle indices while the Process was made up of 'Stimulation mechanisms' and 'Participation of stakeholders and Knowledge flow' Middle indices. In order to calculate the comprehensive evaluation index, our model gave a weight to each indicator/index and applied a weighted arithmetic mean. Korea ranked $15^{th}$ out of 30 OECD nations in the comprehensive evaluation that analyzed Input ($14^{th}$), Process ($18^{th}$), and Output ($17^{th}$). The top five nations were Switzerland, Sweden, Denmark, Germany, and France; while Japan was $8^{th}$ and the USA $26^{th}$.

Al6061 합금의 열간 압출공정에서 금형 냉각시스템에 의한 압출재의 결정립 성장 제어 (Reduction of Grain Growth for Al6061 Alloy by the Die Cooling System in Hot Extrusion Process)

  • 고대훈;이상호;고대철;김호관;김병민
    • 대한기계학회논문집A
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    • 제33권7호
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    • pp.673-680
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    • 2009
  • In this study, die cooling system using the nitrogen gas has been applied to hot aluminum extrusion process for refining grains and reducing of grain growth. Computational fluid dynamics(CFD) has been carried out to evaluate die cooling effect by nitrogen gas, and the results of CFD have been used to FE-simulation for the prediction of the extrudate temperature in hot extrusion process. Experimental hot extrusion has been performed to observe microstructure and to measure temperature of extrudate. The results of FE-Simulation have been good agreement with those of experiment. Finally, process condition of hot extrusion can be established to reduce grain growth of Al6061 through the experiment.