• 한국환경보건학회지
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• 제33권3호
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• pp.217-226
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• 2007

The purpose of this study is to estimate the emission factor of $non-CO_2$ global warming gases such as $N_2O$ and $CH_4$ by measuring concentrations from stacks of waste incinerators and cement production plants. Based on the established monitoring methods, $N_2O$ concentration measured from stacks in incinerator were between 0.62 and $40.60\;ppm_v$ (ave. $11.50\;ppm_v$). The concentration of $N_2O$ was dependent on the incinerator types. However, the concentrations of $CH_4$ gas were between 2.65 and $5.68\;ppm_v$ (ave. $4.22\;ppm_v$), and did not show the dependency on the incinerator types. In the cement production plant, the concentration ranges of $N_2O$ from the stack were from 6.90 to $10.80\;ppm_v$ (ave. $8.60\;ppm_v$), and $CH_4$ were between 1.80 and $2.20\;ppm_v$ (ave. $2.60\;ppm_v$). Using measured concentrations, the emission amounts of $N_2O$ and $CH_4$ from stacks per year were calculated. The results were is 4.2 ton $N_2O/yr$ in the incinerators, and 53.7 ton $N_2O/yr$ in the cement facilities. The big difference is from the flow rate of flue gas in the cement facilities compared to the incinerators. By the same reason, the $CH_4$ emission amounts in cement plant and incinerator was found to be 339 ton $CO_2/yr$ and 34.1 ton $CO_2/yr$, respectively. Finally, the emission factor of $N_2O$ in the incinerators were calculated using the measured concentration and the amount of incinerated wastes, and was $42.5\sim799.1\;g/ton$ in kiln and stoker type, $11.9\sim79.9\;g/ton$ in stoker type, 90.1 ton/g in rotary kiln type, 174.9 g/ton in fluidized bed type, and 63.8 g/ton in grate type, respectively. Also, the emission factors of $CH_4$ were found to 65.2-91.3 g/ton in kiln/stoker type, 73.9-122 g/ton in stoker type, 109.5 g/ton rotary kiln, and 26.1 g/ton in fluidized bed type. This result indicates that the emission factor in incinerators is strongly dependent on the incinerator types, and matched with result of IPCC (International Panel on Climate Change) guideline.

• 한국환경과학회지
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• 제16권9호
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• pp.1077-1083
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• 2007

[ $V_2O_5/TiO_2$ ] catalyst impregnated ceramic candle filters are in principle, capable of performing shallow-bed dust filtration plus a catalytic reaction, promoted by a catalytic deposited in their inner structure. Pilot-scale $V_2O_5/TiO_2$ catalyst impregnated ceramic candle filters were prepared, characterized and tested for their activity towards the SCR reaction. The effect on NO conversion of operating temperature, gas hourly space velocity, amount of deposited catalyst, pressure drops and long-term experiment (life of catalytic filter) was determined. The following effects of $V_2O_5/TiO_2$ catalyst impregnated ceramic candle filters in SCR reaction are observed: (1) It increases the activity and widens the temperature window for SCR. (2) When the content of $V_2O_5$ catalyst increases further from 3 to 9wt.%, activity of NO increases. (3) NO conversion at first increases with temperature and then decreases at high temperatures (above $400^{\circ} over), possibly due to the occurrence of the ammonia oxidation reaction.

• 한국미생물·생명공학회지
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• 제21권4호
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• pp.373-380
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• 1993

When the cells of yeast K35 were immobilized in Ca-alginate gel, cell concentration and viability decreased as alginate concentration increased. Considering the results, 2% (w/v) Ca-alginate concentration would be suitable. Among various concentrations of additives and cross-lin-king agent, the addition of 1.67% (w/v) of bentonite together with 0.33% (v/v) of glutaraldehyde (ABG bead) resulted in the highest ethanol production of 1.8%(w/v), using YPD medium containing 2% glucose. ABG bead seemed to be more resistant to phosphate ion than Ca-alginate bead. 0.33%(w/v) of phosphate was a proper concentration for the ethanol production by ABG bead. Scanning electron microscopic observation depicted that the immobilized cells on the bead surface were coated by alginate gel and that the cells in the internal bead were cross-linked with alginate matrix. When repeated-batch culture was performed with ABG bead for 40 days in a packed-bed reactor, ethanol concentration of about 90~110 g/l-gel was maintained. Cell viability was maintained around 70%, and outgrowing cell concentration was below 6.3% of total cell concentration. Consequently, the results showed that ABG head was a potential carrier for continuous production of ethanol compared to conventional Ca-alginate bead.

• 전력전자학회논문지
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• 제25권5호
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• pp.412-419
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• 2020

In this study, a 70 W buck converter using GaN metal-oxide-semiconductor field-effect transistor (MOSFET) is developed. This converter exhibits over 97 % efficiency, high power density, and 48 V-to-12 V/1.2 V/1 V (triple output). Three gate drivers and six GaN MOSFETs are placed in a 1 ㎠ area to enhance power density and heat dissipation capacity. The theoretical switching and conduction losses of the GaN MOSFETs are calculated. Inductances, capacitances, and resistances for the output filters of the three buck converters are determined to achieve the desired current, voltage ripples, and efficiency. An equivalent circuit model for the thermal analysis of the proposed triple-output buck converter is presented. The junction temperatures of the GaN MOSFETs are estimated using the thermal model. Circuit operation and temperature analysis are evaluated using a circuit simulation tool and the finite element analysis results. An experimental test bed is built to evaluate the proposed design. The estimated switch and heat sink temperatures coincide well with the measured results. The designed buck converter has 130 W/in³ power density and 97.6 % efficiency.

• Journal of Microbiology and Biotechnology
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• 제1권3호
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• pp.182-187
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• 1991

The effects of acrylonitrile and acrylamide on the enzyme action of nitrile hydratase of Brevibacterium sp. CH1 and CH2 strains used for the biotransformations of nitriles were studied. The excessive substrate (acrylonitrile) and product (acrylamide) inhibited the enzyme activity competitively. In comparison with 0.2 mol/l of CH1 strain, the substrate inhibition of CH2 strain began to appear only at a high acrylonitrile concentration of 0.91 mol/l. In a packed bed reactor, dispersed plug flow model was proposed and this model was proved to be valid by the experiment. Also acrylamide productivity decreased sharply when acrylamide concentration in the substrate solution exceeded 20％ (wt/v).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.217-220
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• 2002

The assessment of PIV to measure the mean velocity and turbulence was carried out over a train of fixed two-dimensional dunes. The agreement between the PIV and LDV is good enough even in regions of flow reversals and high shear. Though limited in the wall normal direction field-of-view, PIV provides instantaneous flow fields, which reveal the complex nature of flow over dunes, as well as more sophisticated analyses such as two-point space correlation and quadrant analysis with a reasonable accuracy.

• 한국환경과학회지
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• 제11권4호
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• pp.355-360
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• 2002

This study was to analyze the right of wrong of gray-water treatment by applying BPBE electrode cell to the effluence water in the terminal disposal plant of sewage. The results were as follows : The best result was obtained with applied voltage 40V and detention time 6 minutes for the BPBE electrode cell which has the graphite-plate in main electro-de, packing coconut activated carbon. The elimination rate of COD of Al-plate was higher than that of graphite-plate in main electrode. The result of electrolysis for 3 hour in parallel circuit showed the using possibility of gray-water according to each elimination rate : COD 59%, T-N 69 %, T-P 69%. The BPBE electrode cell with the Al-plate in main electrode made the best effect for the elimination of algae in lake water and algae were not occurred in electrolytic water.

• 공업화학
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• 제5권2호
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• pp.295-304
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• 1994

담지촉매인 $Mo-V-O/SnO_2$(VM/Sn)와 $SnO_2/Mo-V-O$(Sn/VM) 촉매를 제조하여 XRD, BET, SEM, $NH_3$, TPD 등으로 특성분석을 실시하였다. 고정층 연속 반응기에서 아크롤레인의 산화반응을 수행한 결과 이들 촉매의 아크롤레인 전화율과 아크릴산 수율이 Mo-V-O 자체보다 높았다. 이와 같은 상승효과의 원인을 TPD, TPR, TPO 등의 방법으로 고찰한 결과 Mo-V-O와 $SnO_2$의 접촉면에서 Mo-V-O가 $SnO_2$ 상으로 전자를 전달하고 $SnO_2$는 spill-over oxygen을 Mo-V-O 상으로 전달함으로써 반응에 의하여 부분환원된 Mo-V-O의 재산화를 촉진시키는 상간협동 현상이 존재하기 때문으로 판단되었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권3호
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• pp.174-180
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• 2000

Cyclodextrin glucanotransferase (CGTasa) from Thermoanaerobacter sp. was adsorbed on the ion exchange resin Amberlite IRA-900. The optimum conditions for the immobilization of the CGTase were pH6.0 and 600 U CGTase/g resin, and the maximum yield of immobilization was around 63% on the basis of amount ratio of the adsorbed enzyme to intial amount in the solution. Immobilixation of CGTase shifted the optimum temperature for the enzyme to peoduce transglycosylated xylitol from 7$0^{\circ}C$ to 9$0^{\circ}C$ and improved the thermal stability of immobilized CGTase, especially after the addition of soluble starch and calcium ions. Transglycosylated xylitol was continuoncly produced using immobilized CGTase in the column type packed bed reactor, and the operating conditions for maximum yield were 10%(w/v) dextrin (13 of the dextrose equivalent) as the glycosyl donor, 10%(w/v) dextrin (13 of the dextrose equivalent) as the glycosyl donor, 10%(w/v) xylitor as the glycosyl acceptor, 20mL/h of medium fiow rate, and 6$0^{\circ}C$. The maximum yield of transglycosylated xylitol and productivity were 25% and 7.82 g.L-1.h-1, respectively. The half-life of the immobilized CGTase in a column type packed bed reactor was longer than 30 days.

• 복식문화연구
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• 제18권1호
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• pp.109-117
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• 2010

편성물은 여러 가지 형태의 편성 조직을 얻기 위해서 횡편기나 환편기 등의 다양한 니트 편기를 이용하여 다양한 형태의 니트 편환과 조건에 의해서 편성을 하게 된다. 입체적인 형태의 니트 편지는 각기 다른 니트 편환 조직의 병용, 다양한 편사의 이용, 또는 여러 가지 가공공정 등을 거쳐서 얻을 수 있다. 본 연구는 컴퓨터화된 자동 횡편기를 이용하여 편성에 있어서 기본이 되는 조직인 리브편과 펄편의 편성조직을 효과적으로 혼합 편성하여 새로운 형태의 입체 니트구조를 갖는 편지를 개발하는데 그 목적이 있다. 이러한 입체 니트조직을 바탕으로 하여 몇 가지 다른 형태의 입체구조를 갖는 편성물을 개발하고, 새로운 형태의 니트 패션 의복을 제작한다. 또한 리브편과 펄편에 의한 입체 편성조직의 원리와 특성 등에 대하여 논한다.