• 대한기계학회논문집B
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• 제28권3호
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• pp.265-270
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• 2004

Experiment study on a down scaled two-phase catalytic reactor is presented. As a preliminary step for the development of catalytic reactor, nano-particulate catalyst was prepared. Perovskite La$\_$0.8/Sr$\_$0.2/CoO$_3$is chosen and synthesized as a catalyst considering superior catalytic performance in reduction and oxidation process where oxygen is involved among the reagent. Reactor that has a scale of 2${\times}$10${\times}$25mm was made by machining of A1 block as a layered structure considering further extension to micro-machining. Hydrogen peroxide of 70wt% was adopted as reactant and was provided to the reactor loaded with 1.5 g of catalyst. Reactant flow rate was varied by precision pump with a range of 0.15cc/min to 17.2cc/min. Temperature distribution within reactor was recorded by 3 thermocouples and total amount of liquid product was measured. Temperature distribution and factors that affect temperature were observed and relation between temperature distribution and production rate was also analyzed. Relative time scale plays a significant role in the performance of the reactor. To obtain steady state operation, appropriate ratio of flow rate, catalyst mass and reactor geometry is required and furthermore to get more efficient production rate temperature distribution should be evenly distributed. The database obtained by the experiment will be used as a design parameter for micro reactor.

• 환경위생공학
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• 제14권4호
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• pp.117-123
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• 1999

The analytical instrument method was applied to analyze malodorous sulfur compounds emitted from industrial fields. Six factories and two sites which release malodorous substances into ambient air were selected to determine the level of hydrogen sulfide($H_2S$), methylmercaptan(MeSH), dimethyl sulfide($Me_2S$), and dimethyl disulfide($Me_2S_2$) using automated thermal desorption system (STD400) and GC-FPD in summer and fall seasons of 1999. The Air sampler for ATD400 uses a small pump to draw sample and a mass flow controller to adjust sample amount without using a dilution apparatus. The trap temperature of ATD400 reached to $-80^{\circ}$ by supplying liquid nitrogen and $H_2S$ can be analyzed under this condition. The recovery rates of $H_2S$, MeSH, $Me_2S$, and $Me_2S_2$ of odorous sulfur compounds standard were shown 98.2%, 93.6%, 98.2%, 99.4% respectively. The concentrations of $Me_2S$ at outside boundary of G market, L factory, and J factory were 0.018ppm, 0.021ppm, 0.032ppm in summer, respectively. The concentration of $H_2S$ at Nanjido landfill was 1.167ppm in summer, but that of $H_2S$ was not detected in fall because of soil covering. The concentration of H2S and $Me_2S_2$ at inside of Chonggye stream were 0.564ppm and 1.045ppm in summer, while those of H2S and Me2S2 were 0.285ppm and 0.465ppm in fall, respectively.

• 분석과학
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• 제28권5호
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• pp.353-360
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• 2015

지하수 중 라돈은 끓임으로서 쉽게 제거할 수 있다. 다양한 라돈 농도를 가진 13 개 지하수 시료를 이용하여 가열 시간과 온도를 변경시키며 라돈의 제거효율을 평가하였다. 지하수 시료는 Bladder 펌프를 이용하여 채수하였고 용존산소, 수소이온농도 등의 현장수질은 Flow cell을 이용하여 측정 하였다. 경과시간 및 수온 별로 분취한 시료의 라돈 농도는 액체섬광계수기(LSC)로 분석하였다. 실험결과, 온도가 높을수록 경과시간에 따른 지하수 중 라돈의 제거율도 높아지며 지하수 중 라돈의 초기농도가 높을수록 경과시간에 따른 지하수 중 라돈의 제거율은 낮아진다. 즉, 지하수 중 라돈의 농도가 높을수록 가열에 의한 라돈 제거 시 더 많은 시간과 에너지를 필요로 한다. 따라서 지하수 중 라돈 제거율은 주로 라돈초기농도, 가열온도, 그리고 가열시간에 의해 결정된다.