• Transactions of the Korean hydrogen and new energy society
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• v.22 no.1
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• pp.51-59
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• 2011

Sulfur-Iodine (SI) cycle, which thermochemically splits water to hydrogen and oxygen through three stages of Bunsen reaction, HI decomposition, and $H_2SO_4$ decomposition, seems a promising process to produce hydrogen massively. Among them, the decomposition of $H_2SO_4$ ($H_2SO_4=H_2O+SO_2+1/2O_2$) requires high temperature heat over $800^{\circ}C$ such as the heat from concentrated solar energy or a very high temperature gas-cooled nuclear reactor. Because of harsh reaction conditions of high temperature and pressure with extremely corrosive reactants and products, there have been scarce and limited number of data reported on the pressurized $H_2SO_4$ decomposition. This work focuses whether the $H_2SO_4$ decomposition can occur at high pressure in a noble-metal reactor, which possibly resists corrosive acidic chemicals and possesses catalytic activity for the reaction. Decomposition reactions were conducted in a Pt-lined tubular reactor without any other catalytic species at conditions of $800^{\circ}C$ to $900^{\circ}C$ and 0 bar (ambient pressure) to 10 bar with 95 wt% $H_2SO_4$. The Pt-lined reactor was found to endure the corrosive pressurized condition, and its inner surface successfully carried out a catalytic role in decomposing $H_2SO_4$ to $SO_2$ and $O_2$. This preliminary result has proposed the availability of noble metal-lined reactors for the high temperature, high pressure sulfuric acid decomposition.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.10b
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• pp.91-97
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• 1996

Bench Scale급 가스화기를 이용하여 중국 대동탄에 대하여 O2/coal 비, 가스화기 운전 압력에 따른 가스화 특성을 조사하였다. 가스화기를 가압하는 방법으로 메탄과 산소의 버너를 이용하여 운전 압력까지 단시간 내에 가압하는 방법을 정립하였다. 가스화기 압력은 상압으로부터 10기압까지 실험을 실시하였으며, 10기압, 반응온도 1350-140$0^{\circ}C$, O2/coal 비(as-fed 기준) 0.9의 운전조건에서 탄소전환률 90%이상, 냉가스효율 60%, 그리고 heating value 1800 Kcal/N㎥ 정도의 생성가스 특성을 얻을 수 있었다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.173-177
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• 2002

두 개의 유동층 사이를 순환하는 금속매체(Metal or Metal oxide)를 이용하여 공기에 의한 금속매체의 산화와 기체연료(H$_2$, CO, CH$_4$등)에 의한 금속산화물의 환원반응이 별개의 반응기에서 일어나게 하는 새로운 개념의 연소기술인 매체순환식 가스연소기술은 공기와 기체연료를 직접 접촉시켜 반응하는 기존의 가스연소기에 비해 많은 장점을 가지고 있다.(중략)

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.4
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• pp.79-93
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• 1984

The dissolved air flotation(DAF) has been shown to be efficient process for the removal of algae ftom water. The efficiency of DAF can be affected by the volume ratio of pressurized liquid to sample, the pressure pressurized liquid, the contact time, the appropriate coagulant and its amount, the water temperature, the turbulence of reactor, the bubble size and rising velocity etc. The purpose of this paper is to compare the practical bubble rising velocity with the theoretical one, to investigate the adhesion phenomenon of bubbles and floc, and the influence of bubble size and velocity upon the process. The results through theoretical review and experimental investigation are as follows: Ives' equation is more suitable than Stokes' equation in computation of the bubble rising velocity. The collection of bubble and algae floc is convective collection type and resulted from absorption than adhesion or collision. The treatment efficiency is excellent when the bubble sizes are smaller than $l00{\mu}m$, and the turbulence of reactor is small. In the optimum condition of continuous type DAF the volume ratio of pressurized liquid to sample is 15%, the contact time in reactor is 15 minutes, the pressure of pressurized liquid is $4kg/cm^2$ and the distance from jet needle to inlet is 30cm.

• Korean Chemical Engineering Research
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• v.47 no.5
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• pp.546-552
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• 2009

Enzymatic ethanolysis of wheat germ oil with immobilized lipase was investigated for enhancing the function of wheat germ oil. Ethanolysis reactions were carried out in two different systems; non-pressurized and pressurized system. In non-pressurized system, the enzymatic ethanolysis was carried out in an erlenmeyer flask(25 ml) containing a mixture of wheat germ oil and 99.90% ethanol using 1~5 wt% immobilized lipase as Lipozyme TL-IM and Lipozyme RM-IM and the reaction mixtures were incubated at $40{\sim}70^{\circ}C$ with 120 rpm shaking. In pressurized system, the enzymatic ethanolysis was carried out at various condition; immobilized lipase concentration(2 wt%), reaction time(24 h), reaction temperature($40{\sim}60^{\circ}C$) and reaction pressure(75, 100, 150, 200 bars). The samples obtained from each fraction were analyzed by HPLC for analysing contents of monoglyceride, diglyceride, and triglyceride. The conversion of wheat germ oil relied on the reaction temperature and the concentration of immobilized lipase. The optimum condition of enzymatic ethanolysis in non-pressurized and pressurized systems was at $50^{\circ}C$ and 100 bar.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.182-183
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• 2019

In this study, the optimization of mixing proportion of press-forming board with blast furnace slag, pearlite and bottom ash was investigated using the response surface methodology. Ten Mixing proportions of specimens were designed by the response surface design, and then flexural failure load, moisture content and water absorption of specimens were measured. As a result of the reaction surface analysis based on the experimental results, it was possible to derive the optimal mixing proportion with the satisfaction of 93%.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.591-602
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• 1995

가압경수로에서는 장기적인 반응도 조절을 위하여 B-10과 B-11을 함유한 천연붕산을 사용한다. 천연붕산의 사용으로 원자로냉각재의 붕소농도가 높기 때문에 pH를 적정한 범위로 유지하기 위하여 많은 양의 수산화리튬이 주입된다. 이로 인한 높은 리튬 농도는 증기발생기 재질의 응력부식균열과 핵연료피복재의 산화를 촉진시키는 등의 부작용을 초래할 수 있다고 보고되었다. 따라서 본 고에서는 천연붕산을 B-10 함량이 높은 농축붕산으로 대체하는 경우에 대한 기술적, 경제적 영향을 조사하고 검토하였다. 조사 결과, 농축붕산은 원전의 일차계통 수질화학, 부식생성물의 방사화에 의한 선량율, 보조계통 설계, 액체폐기물 발생량관점에서 여러가지 이점이 있을 수 있으며, 노심설계, 안전해석, 발전소 인허가 등의 관점에서는 문제가 없다고 밝혀졌다. 현재 천연붕산으로 운전중인 원전에서는 농축붕산의 경제성이 발전소의 주어진 제반여건에 의존하고, 농축붕산의 가격에 따라 크게 차이가 있는 것으로 보고되었다. 국내에 신규 원전이 계속적으로 건설되고 있는 현실에 비추어 볼 때, 발전소의 경제성과 안전성을 향상시키기 위하여 농축붕산 사용에 대한 타당성을 좀 더 면밀히 분석 할 필요가 있다고 판단된다.

• Journal of Life Science
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• v.22 no.4
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• pp.545-551
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• 2012

Pressurization walk training (PWT) with blood flow occlusion has been investigated with regard to muscle hypertrophy and physical fitness function in athletes and healthy people. However, the cardiorespiratory and cardiovascular responses of obese people to PWT are unknown. Thus, we investigated the effects of PWT on body composition (Weight, FM, LBM, %fat, BMI), cardiovascular responses (HR, SV, CO, TVC), and cardiorespiratory responses ($VO_2max$, VEmax, HRmax) in middle-aged obese women. They participated in walk training with (n=15) blood flow occlusion and cross-sectional areas of the quadriceps on both legs. Five sets of 3-min walking (5.5 km/h at 5% grade) and 1-min resting were performed twice a day, 5 days/week for 3 weeks. The results showed that the LBM was significantly increased, and decreased body weight of reducing FM, %bodyfat in PWT ($p$<0.05). For the cardiovascular response, SBP and TPR were significantly decreased ($p$<0.05), and CO increased ($p$<0.05). In addition, the $VO_2max$ and VEmax were improved through PWT. Therefore, this study suggests that the presence of obesity in middle-aged women may result in body composition, cardiorespiratory, and cardiovascular responses caused by PWT.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.11a
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• pp.243-250
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• 2001

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.05a
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• pp.163-163
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• 2001