• 멤브레인
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• 제7권4호
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• pp.175-182
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• 1997

혐기-호기의 생물반응조 공정과 막분리 공정을 조합한 막-생물반응조 공정을 이용하여 염색폐수 중의 난분해성 물질들을 제거하였다. 염색폐수 원수를 직접 막분리공정에 적용한 결과 심각한 fouling을 초래하였다. 반면 생물반응조로 1차 처리한 후 막분리공정에 적용한 경우 생물반응조가 막의 오염원을 상당부분 제거하여 fouling현상이 현저리 감소하였으며, 막의 수명도 연장시킬 수 있었다. 염색폐수의 처리효율 및 fouling현상은 막의 기공 크기나 구조보다는 막의 재질에 더욱 의존함을 확인하였다. 중공사막 module의 사용 방법 및 중공사막 내부의 유속에 따라서 제거효율 및 투과유량이 변화하였다. 생물반응조나 막분리 단독공정보다 두공정을 조합한 공정이 보다 효과적으로 염색폐수 처리능력을 보였다.

• 상하수도학회지
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• 제13권1호
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• pp.113-124
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• 1999

We elucidated factors such as membrane pore size, activity of the activated sludge and MLSS. affecting filtering characteristics or filtering resistance in an activated sludge bio-process using tubular type membranes. We used a commercial membrane module with $0.5m^2$ of effective membrane area and a bundle of 7 tubes(13mm of ID and 2m long) in the experiments. As a result, the flux was maintained in the range of $35{\sim}105l/m^2$ hr at 5,000~20,000mg/l of MLSS concentration, and there seemed to be a correlation between the flux and the MLSS. Also the greater the pores were, the higher the flux was in some comparison experiments using UF and MF membranes, but the water permeated through both of the membranes showed almost the same quality. However, the MF membrane showed a great reduction in filtering resistance initially, but went back to a stable stage afterwards. The activity of the activated sludge in the aeration tank was also found to be considered as a factor showing permeation characteristics of the membrane.

• 한국축산식품학회지
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• 제42권3호
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• pp.411-425
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• 2022

Semi-dried restructured sausages are restructured meat products with a high nutritional and economic value. However, excessively long drying times can have negative effects on the energy consumption, texture, and sensory properties of semi-dried restructured sausages. The objective of this study was to investigate the effects of different water contents on the drying and physicochemical characteristics of semi-dried restructured sausages. Sausages were prepared with different initial moisture contents (0%-50%) and drying time (0-580 min). The drying characteristics, including the drying rate, effective moisture diffusivity, and water activity of sausage were significantly improved as the initial moisture content was increased. When the initial moisture content of the sausage was 50%, physicochemical properties, such as color, porosity, shear force, and volatile basic nitrogen, were improved the most along with the decreased drying time. Scanning electron microscopy data showed greater porosity and pore size in sausages with the increase of initial moisture content. Collectively, our data suggest that an increase in the initial moisture content of semi-dried restructured sausages improves their drying characteristics and physicochemical properties.

• 한국초전도ㆍ저온공학회논문지
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• 제8권3호
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• pp.5-8
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• 2006

The effect of annealing time in Metal Organic Deposition(MOD) method was investigated at reduced total pressure. As the total annealing pressure was reduced, the growth rate of YBCO films increased from 0.14nm/sec at atmospheric pressure to 4.2nm/sec at 1 Torr. For the total pres sure of 700, 500, 300, 100, and 1 Torr, the optimal annealing times of 60, 40, 20, 10, 2minutes were found in our experimental conditions. When the an nealing time was short, poor crystallinity or un-reacted phase was obtained. Also, the degradation of YBCO films occurred when exposed longer to the humid ambient at the high annealing temperature. The reduced pressure was found effective to in crease the growth rate and to control the pore size of the YBCO films in MOD method. A fast growth of MOD-YBCO films was realized with high critical current density over $1MA/cm^2$ using reduced pressure annealing. Large pores, usually observed at atmospheric pressure in MOD method, disappeared and also, the number of pores was reduced.

• 한국초전도ㆍ저온공학회논문지
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• 제8권1호
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• pp.5-8
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• 2006

The growth properties of MOD-YBCO films were investigated. To enhance the growth rate of YBCO layer and inhibit the build-up of HF gas during the annealing process in TFA-MOD for YBCO coated conductors the method of low pressure annealing was employed. Total pressure was changed from 700Torr to 1Torr and its effect on growth of YBCO films was compared with atmospheric one. The lower Pressure was effective to control of the pore size in MOD method . Surface morphology of YBCO films processed at low total pres sure was rough and composed of random YBCO (103) grains. But large pores, usually observed at atmospheric process in MOD disappeared and also the number of pores was reduced at low pressure annealing. Also discussed ate the effects of Fluorine-free Y and Cu precursor solution on the development of microstructure. Dense surface me phology and with less and small pores can be provided through controlling Fluorine content.

• 대한한의학회지
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• 제44권2호
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• pp.34-44
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• 2023

Objectives: The purpose of this research was to find out the efficacy of Castanea crenata Inner Shell (CCIS) distilled herbal medicine on the skin by comparing the difference effect between only simple distilled water and the CCIS distilled herbal medicine application after MTS (microneedle therapy system) treatment. Methods: The present author performed once a week and total 4 times of MTS treatment. The treatment time took about 5~10 minutes and the depth of the needle was adjusted according to the participant's skin condition. In the control group, simple distilled water was applied after MTS and in the experimental group, CCIS distilled herbal medicine was applied. One week after each treatment, the change of skin condition was measured. Two weeks after the end of the clinical trial, the skin condition was checked again. Results: In the case of the test group, there was a significant decrease in pore size and there was a significant increase in U-zone oil, skin tone and elasticity. The test group using distilled herbal medicine showed a significant effect on facial skin compared to the control group using only simple distilled water. Conclusion: Distilled herbal medicine showed an effective action on facial skin. In the case of CCIS distilled herbal medicine, it was found to have a significant effect on U-zone oil content, skin tone, pores, and skin elasticity.

• 새물리
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• 제68권12호
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• pp.1315-1323
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• 2018

본 연구에서는 폐 커피분말을 열처리 조건에 따른 탄화과정을 거쳐 리튬 이온 이차전지의 음극 활물질 재료로 응용하기 위한 실험을 진행하였다. 이차전지의 음극 활물질로 사용한 커피분말은 커피 껍질이 아닌 커피 알맹이로부터 얻은 것으로, 커피를 내리고 남은 커피분말을 공기 중에서 건조하고 $Ar/H_2$ 분위기에서 열처리하여 기공(pore)이 있는 활성 탄소 분말 형태로 얻을 수 있었다. 전기화학적인 특성을 조사한 결과 약 0.2 V에서 Li의 삽입, 0.01 V에서 Li의 탈리가 관찰되었다. $700^{\circ}C$에서 열처리된 시료에 대해 1000 mA/g의 전류밀도로 1000 사이클 충방전 후 측정된 비용량은 303 mAh/g 이었으며 99.5% 이상의 쿨롱(Coulomb) 효율을 나타내었다. 폐 커피분말을 이용한 리튬이온이차전지는 기공으로 인한 표면적 증가와 이온 및 전자전도 특성 개선으로 전기화학적인 성능 향상을 보였으며, 또한 재활용을 통한 전지 제조 가격을 낮출 수 있는 이점이 있다.

• 구강회복응용과학지
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• 제22권4호
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• pp.349-365
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• 2006

State of problem : A number of investigation about increase of surface area via various surface treatments and modification of surface constituent have been carried out. Purpose : The surface characteristics and stability of implants treated with anodic oxidation, fluoride ion incorporation, and groups treated with both methods were evaluated. Material and method : Specimens were divided into six groups, group 1 was the control group with machined surface implants, groups 2 and 3 were anodic oxidized implants (group 2 was treated with 1M $H_2SO_4$ and 185V, group 3 was treated with 0.25M $H_2SO_4$ and $H_3PO_4$ and 300V). Groups 4, 5 and 6 were treated with fluoride. Group 4 was machined implants treated with 0.1% HF, and groups 5 and 6 were groups 2 and 3 treated with 10% NaF respectively. Using variable methods, implant surface characteristics were observed, and the implant stability was evaluated on rabbit tibia at 0, 4, 8 and 12 weeks. Result : 1. In comparison of the surface characteristics of anodic oxidized groups, group 2 displayed delicate and uniform oxidation layer with small pore size containing Ti, C, O and showed mainly rutile, but group 3 displayed large pore size and irregular oxidation layer with many crators. 2. In comparison of the surface characteristics of fluoride treated groups 4, 5, 6 and non-fluoride treated groups 1, 2, 3, the configurations were similar but the fluoride treated groups displayed rougher surfaces and composition analysis revealed fluoride in groups 4, 5, 6. 3. The fluoride incorporated anodic oxidized groups showed the highest resonance frequency values and removal torque values, and the values decreased in the order of anodic oxidized groups, fluoride treated group, control group. 4. According to implant stability tests, group 2 and 3 showed significantly higher values than the control group (P<.05). The fluoride treated groups showed relatively higher values than the non fluoride treated groups and there were significant difference between group 4 and group 1 (P<.05). Conclusion : From the results above, it can be considered that the anodic oxidation method is an effective method to increase initial bone stability and osseointegration and fluoride containing implant surfaces enhance new bone formation. Implants containing both of these methods should increase osseointegration, and reduce the healing period.

• 청정기술
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• 제24권1호
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• pp.27-34
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• 2018

분진과 질소 산화물을 동시에 처리할 수 있는 이원적 기능을 가진 촉매 필터는 산업체 적용에 많은 장점을 갖고 있다. 통기성이 높은 시트 형 세라믹 필터를 촉매 필터 소재로 활용하면 배기가스 처리 공정의 타당성을 더욱 높일 것이다. 그러나 시트 필터는 두께가 얇아서 촉매 지지층에 촉매를 부착할 수 있는 공간이 부족하므로 효과적인 촉매필터를 제조하기가 쉽지 않다. 본 연구에서는 국산 시트 필터를 사용하여 촉매 필터를 제조하고 실험실 장치에서 제조된 촉매 필터의 NO 환원 성능이 평가되었다. 현재 시판되고 있는 시트 필터로 촉매 필터를 제조할 경우 여과속도 $2m\;s^{-1}$에서 700 ppm NO 농도에 대한 NO 전환율이 92% 이하로써 촉매 필터 재료로써 좋은 특성을 나타내지 못했다. 이와 같이 저조한 특성을 보이는 이유는 시트 필터의 촉매 지지층의 기공이 균일하지 못하여 필요 이상의 큰 기공이 존재하기 대문으로 해석되었다. 필터에 존재하는 큰 기공의 사이즈를 줄이기 위하여 필터를 제조하는 원재료에 작은 입자를 혼합하여 시트 필터의 기공을 줄이는 효과를 통하여 NO 전환율 96% 이상을 달성하였다. 또한 촉매 지지체로써 큰 입자의 $TiO_2$를 혼합하여 촉매층의 기공을 팽창시켜서 개선된 촉매 필터는 상용 요구에 충족되는 98% 이상의 NO 전환율을 보였다. 위 두 경우 모두 촉매층 내에 존재할 수 있는 큰 기공을 효과적으로 메워서 적절한 촉매층이 형성되면 촉매 필터의 성능이 향상되는 결과를 보인 것이다. 따라서 이와 같이 통기도가 우수한 장점을 가진 시트 필터가 촉매 필터의 소재로 잘 활용될 수 있음을 보였다.

• 한국분말재료학회지
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• 제18권1호
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• pp.41-48
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• 2011

As a pore precursor, carbon black with different content of 0 to 60 vol% were added to (Ba,Sr)$TiO_3$ powder. Porous (Ba,Sr)$TiO_3$ ceramics were prepared by pressureless sintering at $1350^{\circ}C$ for 1h under air. Effects of carbon black content on the microstructure and PTCR characteristics of porous (Ba,Sr)$TiO_3$ ceramics were investigated. The porosity of porous (Ba,Sr)$TiO_3$ ceramics increased from 6.97% to 18.22% and the grain size slightly decreased from $7.51\;{\mu}m$ to $5.96\;{\mu}m$ with increasing carbon black contents. PTCR jump of the (Ba,Sr)$TiO_3$ ceramics prepared by adding carbon black was more than $10^5$, and slightly increased with increasing carbon black. The PTCR jump in the (Ba,Sr)$TiO_3$ ceramics prepared by adding 40 vol% carbon black showed an excellent value of $9.68{\times}10^5$, which was above two times higher than that in (Ba,Sr)$TiO_3$ ceramics. These results correspond with Heywang model for the explanation of PTCR effect in (Ba,Sr)$TiO_3$ ceramics. It was considered that carbon black is an effective additive for preparing porous $BaTiO_3$ based ceramics. It is believed that newly prepared (Ba,Sr)$TiO_3$ cermics can be used for PTC thermistor.