http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 유동석(Dong-Suk Yoo) (검색결과 6 건)
- 무료
- 기관 내 무료
- 유료
-
-
-
레이저 유도초음파(LBU)를 이용한 고온에서 물성측정에 관한 연구
백영기(Young-Ki Baek),유동석(Dong-Suk Yoo) 산업기술교육훈련학회 2012 산업기술연구논문지 (JITR) Vol.17 No.2
In this research, using laser-guided ultrasonic inspection system to measure the properties at high temperatures was on purpose. One of propose laser-based ultrasonic technology is a non-contacted, remote measurements. It is possible to measure an ultrasound at high temperatures using laser-based ultrasonic because the benefits of laser-based ultrasonic was a remote and non-contact measurement, but convention methods was not possible at high-temperatures. For the detection of ultrasound at high temperatures were a variety of researches in progress. This study is divided into two parts. First, according to the direction of the progress of the ultrasound, properties at normal temperature were detected. Depending on the progress of the ultrasound direction, the velocity of ultrasound was measured and compared respectively. Secondly, the specimen into the high temperature-electric furnace, changes in temperature, and the measurement of the ultrasound signal. Temperature of the furnace was changed 0 ℃ to 1000℃. In conclusion, depending on the temperature rise has reduced the speed of ultrasound. And Young s modulus was also reduced. However, the Poisson s ratio was increased. In particular, the velocity of ultrasound and Young s modulus is the increasing decline in the near a 400℃. Through this research in high-temperature laser-based ultrasonic to prove that the ultrasound was ideal for transmitting and receiving. Additional research is needed to overcome the environmental restrictions.
-
-
이광래,유동석,강석원 강원대학교 석재복합신소재제품연구센터 1997 석재연 논문집 Vol.2 No.-
수산화칼슘 슬러리(aqueous Ca(OH)₂ slurry) 농도가 비교적 높은 1 wt% ∼7 wt% 범위에서 공정변수인 탄산가스 유량과 교반속도에 다른 물질전달계수를 구하고, 수산화칼슘 슬러리의 농도변화에 따른 입자형태 및 입자크기 변화를 관찰하였다. 수산화칼슘 슬러리의 농도에 따른 탄산화반응은 0차반응이었으며, CO₂에 대해서는 1차반응이었다. 따라서 탄산화반응은 0차반응과 1차반응이 혼재된 준1차반응임을 알 수 있었다. 반응종결점은 수산화칼슘 슬러리의 농도가 증가함에 따라 pH 및 전기전도도법에 의한 예측보다 늦어지는 것으로 나타났다. 물질전달속도는 수산화칼슘 슬러리의 농도(0.158∼7wt%)와 교반속도(300∼700rpm)에 무관하게 각각 일정한 값을 나타내었고, CO₂ 유량의 증가에 따라서는 비례적으로 증가하였다. 이러한 물질전달은 탄산화반응으로 인하여 증진되어짐을 알 수 있었으며, 증진인자(enhancement factor, Φ)는 1.394였다. 기체측 경막저항은 다른 물질 전달저항에 비하여 무시할 수 있을 정도로 작았으며, CO₂와 OH(???)간의 반응이 매우 빠른 반응이므로 탄산화반응시의 물질전달속도를 지배하는 물질전달저항은 OH(???)의 해리속도와 관련된 고-액 경막을 통한 물질전달저항임을 알 수 있었다. 본 실험의 수산화칼슘 슬러리의 농도범위(0.158∼7wt%)에서 생성된 탄산칼슘은 서브마이크론(submicron) 크기의 탄산칼슘이었으며, 결정구도는 방해석(calcite) 구조였다. 생성된 탄산칼슘의 입자형태는 Ca(OH)₂의 포화농도(0.158wt%)에서 판상형태였으며, 수산화칼슘[Ca(OH)₂] 슬러리 농도가 비교적 낮은 lwt%∼3wt% 영역에서는 입방체형태였다. 농도가 비교적 높은 4wt%∼7wt%에서는 수산화칼슘 슬러리 농도가 증가함에 따라 입방체 형태가 사라지고, 입자모양은 응집된 형태로서 길게 크졌다. 입자가 길게 크지면서 입방체형태가 없어지는 것은 슬러리 농도가 증가할수록 응집현상이 지배적으로 나타나기 때문으로 판단된다. Since the concentration of hydrated lime is higher than 1wt% in industrial carbonation processes, the carbonation reactions were conducted in relatively high concentration range of aqueous Ca(OH)₂ slurry from 1wt% to 7wt%. Reaction rate, reaction order, and termination time of carbonation reaction as well as mass transfer coefficients which are major variables for reactor design were investigated with concentration of aqueous Ca(OH)₂ slurry, flow rate of carbon dioxide, and agitation speed. Carbonation was a 0th and a 1st order reaction with respect to the concentration of aqueous Ca(OH)₂ slurry and flow rate of carbon dioxide, respectively. Hence it was found that the carbonation was a pseudo 1st order reaction conjugated with 0th and 1st order. It was exhibited that the termination time of reaction measured by titration technique took longer than that predicted by pH and conductivity method due to the agglomeration effect caused by the high concentration of aqueous Ca(OH)₂ slurry. In the range of the experiments, there was no dependency of mass transfer rates on concentration(0.158∼7wt%) of aqueous Ca(OH)₂ slurry and agitation speed (300∼700rpm). However, mass transfer rates were proportionally increased with increasing flow rate of carbon dioxide. Moreover, mass transfer rates were enhanced by carbonation. The enhancement factor(Φ) was 1.394. Gas-film resistance was negligible because it is so small in comparison with other resistances. The reaction between carbon dioxide and hydroxyl ion was fast enough so that the mass transfer rate was controlled by the diffusion through solid-liquid film due to the dissolution of lime in carbonation. The size of calcium carbonate prepared by carbonation reaction in the concentration range of this experiment(0.158w%∼7wt%) was of submicron. At the saturated concentration (0.158wt%) of aqueous Ca(OH)₂ slurry, particle shape of calcium carbonate was a plate form, and its crystal structure was of calcite. At the relatively low concentration (1∼3wt%) of aqueous Ca(OH)₂ slurry, particle shape of calcium carbonate was a cubic. However, in higher concentration (4wt%∼7wt%) the cubic shape disappeared with increasing concentration of aqueous Ca(OH)₂ slurry. The particles became bigger in size and changed to agglomerate shape. It might be inferred that the change of particle size and shape with increasing concentration of aqueous Ca(OH)₂ slurry is due to the agglomeration effect. The agglomeration effect substantially appeared with increasing concentration(4∼7wt%) of queous Ca(OH)₂ slurry.
-
조정식,이광래,유동석,강석원 강원대학교 석재복합신소재제품연구센터 1996 석재연 논문집 Vol.1 No.-
석회유의 탄산화반응에 의하여 생성되는 탄산칼슘의 결정화공정에 대한 정량적 해석을 위하여 개체군 수지식(population balance)을 이산화(discretization)하는 방법에 의해 반회분식 침전결정화기에서 생성된 탄산칼슘의 입도분포를 수치모사하여 실험치와 비교하였다. 수치모사에 의한 탄산칼슘의 입도분포는 실험치와 잘 일치하였으며, 응집이 입자크기에 의존(size-dependent agglomeration)한다고 가정한 경우가 응집이 입자크기와는 무관(size-independent agglomeration)하다고 가정한 경우보다 실험치에 더 근사한 결과를 보였다. 또한, 응집핵(agglomeration kernel)이 깨어짐핵(rupture kernel)보다 입도분포에 미치는 영향이 더 큰 것을 알 수 있었다. For the quantitative analysis of crystallization of calcium carbonate formed by carbonation of lime milk, PSD(particle size distribution) of the calcium carbonate, which is the carbonation product of lime milk, was numerically simulated by the method of discretization of population balance and compared with the experimental data of semi-batch precipitative crystallizer. The simulated PSD was well correlated with the experimental data. And the simulated results of PSD for size-dependent agglomeration were well-matched to the experimental data than for the size-independent agglomeration. Moreover, it was shown that agglomeration kernel had greater effects on PSD than rupture kernel.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
