• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.524-535
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• 2018

In this study, macroporous titania powders were synthesized utilizing the emulsion-assisted self-assembly to apply the removal of B. subtilis under UV irradiation, and the results were compared with the bactericidal effect of commercial titania nanoparticles. By changing the pore size of the porous titania powder, the reduction of B. subtilis by photocatalytic effect was measured, and the bactericidal capacity of the porous particles according to the pore size was compared in order to derive the optimum condition of the sterilization experiment. It was observed that the sterilization effect increased as the pore size became smaller, and it was confirmed that more than 50% of B. subtilis cold be removed for 1 hour of UV irradiation. Also, in order to promote the generation of active chemical species, a diluted solution of hydrogen peroxide was combined with the photocatalytic sterilization method, resulting in the removal of most of the strain after ultraviolet irradiation for 1 hour.

• Membrane Journal
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• v.26 no.6
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• pp.421-431
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• 2016

Novel membrane technologies that harness ordered nanostructures have recently received much attention because they allow for high permeability due to their reduced flow resistance while also maintaining high selectivity due to their isoporous characteristics. In particular, the opaline structure (made from the self-assembly of colloidal particles) and its inverted form (inverse-opal) have shown strong potential for membrane applications on account of several advantages in processing and the resulting membrane properties. These include controllability over the pore size and surface functional moieties, which enable a wide range of applications ranging from size-exclusive separation to catalytically-reactive membranes. Furthermore, when combined with multiscale architecturing strategies, inverse-opal-structured membranes can be designed to have specific pores or channel structures. These materials are anticipated to be utilized for next-generation, high-performance, and high-value-added functional membranes. In this review article, various types of inverse-opal-structured membranes are reviewed and their functionalization through hierarchical structuring will be comprehensively investigated and discussed.

• Journal of Plant Biology
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• v.38 no.1
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• pp.79-86
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• 1995

Visible injury symptoms such as necrosis, chlorosis and premature senscence in the leaves of Ginkgo bloba and Pinus thunbergii treated with acid rain of pH 3.2 or below were observed. The epicuticular wax erosions were observed by SEM after exposure to acid rain of pH 2.4 and 3.2 in G. biloba and pH 4.0 below in P. thunbergii. The adaxial epidennal cells and sponge parenchyma cells were compressed, and those were distorted in the leaves of G. biloba treated with simulated acid rain of pH 3.2 or below. However, vascular tissue was intact. With increase of acidity, mesophyll cells were smaller than those of control while intercellular space in mesophyU was increased. In P. thunbergii, sponge parenchyma cells and vascular tissue except epidennis were distorted after exposure to acid rain of pH 2.4. The size change of stomata in foliar injury was not observed, but the stomatal index and size of stomatal aperture in leaves treated with acid rain increased. The stomata of injured leaf were opened in both species examined.amined.

• Journal of the Society of Disaster Information
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• v.20 no.3
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• pp.593-600
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• 2024

Purpose: In this study, fundamental research was conducted to capture sparks generated during the arc welding process. Method: To this end, a mock-up collection device was developed, consisting of a blower for suction, a nozzle, and a filter and magnet at the suction point. To analyze the correlation between the shape of the filter and its magnetic properties, the porosity and pore size of both carbon filters and Colgate filters were quantified under conditions of a welding machine capacity of 1,800W and a welding time of 70s. The collection efficiency of sparks was calculated for magnetic strengths of 2.6, 3.4, and 4.05kgf. Result and Conclusion: As a result, empirical formulas were derived for the blower's suction capacity, magnetic strength, porosity, and pore diameter for capturing sparks, with experimental results confirming consistency within ± 10%. The findings of this study are expected to provide a quantitative design approach for collection devices that can minimize the risk of fire spread associated with welding operations at construction sites.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.120-125
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• 1998

CO$_{2}$gas중에서 산화된 활성탄소섬유를 77K에서 질소흡착에 의해 흡착등온곡선을 구하였다. 미세공부피와 외부표면적은 t-법으로 구하였으며, 평균기공크기와 기공분포는 Dubinin-Astakhov법으로 구하여 기공발당과정을 고찰하였다. 산화반응 초기(약 40% burn-off까지)에 섬유내부에 발달하는 미세공은 burn-off가 40%를 넘으면 서서히 큰 미세공으로 성장하며, burn-off가 약 60%이상되면 미세기공은 확대 또는 합체되어 점차 중기공으로 성장하는 것으로 관찰되었다. 또한 고온산화반응으로 발달한 기공은 저온에서 생성된 기공보다 크다.

• Journal of the Korean Ceramic Society
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• v.41 no.1
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• pp.62-68
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• 2004

In this study, SHS process has been employed to fabricate porous $MoSi_2$ material with electric-resistive heating capability through the control of pore size. The preform for SHS reaction was consisted of molybdenum powder with different sizes and silicon powder with different contained quantity. The size of the $MoSi_2$ particles thus formed was determined by the generated heat of combustion, not by the size of molybdenum powder. However, the pore size of $MoSi_2$ composite was proportional to the particle size of molybdenum powder. that is the coarser the molybdenum powder used, the larget the formed pore size. Based on these results, the porous $MoSi_2$ composite could be fabricated with a desired pore size. By orienting the porous molybdenum disilicide-based material in the form of pore size gradient, porous materials used for filters with improved dirt-holding capacity can be manufactured.

• Korean journal of food and cookery science
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• v.18 no.2
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• pp.206-210
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• 2002

The bread qualities were analyzed objectively by using CrumbScan software. Samples were prepared at the same conditions of mixing, fermentation, and baking time except the amount of Korean wheat flour (KWF). The bread volume was increased with increasing KWF, and the maximum volume was attained in the product of 20% KWF. Although the products of 20% and 30% KWF showed the same thickness of the crust, the crust was thinner than control when KWF was added. The size (fineness) and shape (elongation) of crumb cells were larger and rounder than control due to the low degree of elasticity of the KWF-added dough. Among the samples, the product with 20% KWF showed the most even distribution of crumb cells around the sliced area. The precise determination of external and internal characteristics of the bread was possible with Crumbscan, suggesting the possibility of developing industrial standards for bread.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.405-406
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• 2003

분진여과시 형성되는 분진 케이크는 궁극적인 여과 성능을 좌우하며, 필터의 구조, 분진 입자의 형태나 크기, 분진농도, 여과속도 등에 의해 영향을 받는다 특히 필터의 표면 구조나 기공 크기는 여과 초기 단계의 케이크 층의 구조를 결정하며, 연속적인 여과시 초기 케이크 층은 다음에 쌓이는 케이크 형성과 비저항에 영향을 주므로 필터 medium 구조 또한 분진여과 과정에서 중요한 영향 요인이 된다. 본 연구에서는 필터 medium의 구조가 서로 다른 고온가스정화용 복합 세라믹 필터, metal fiber mat, 스테인레스 필터를 이용하여 분진농도와 여과속도를 변수로 하여 분진 여과 실험을 함으로써 각각의 필터에 대한 케이크 비저항과 기공율을 실험과 이론식으로부터 추정하였다. (중략)

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.584-587
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• 2008

최근 새로운 천연가스 수송/저장 방법으로 가스 하이드레이트 형성법이 주목받고 있다. 본 연구에서는 천연가스의 저장 매체로 다공성 실리카 젤을 사용하였다. 다공성 매질을 사용할 경우 물이 기체와 접촉하는 면적이 극대화되어 하이드레이트로의 전환율이 높아진다. 기공의 직경이 각각 6.0, 15.0, 30.0 nm의 실리카 젤을 사용하여 270 - 285 K의 온도 범위와 0.5 - 3.0 MPa의 압력 범위에서 기공 크기의 분포를 고려하여 에탄 하이드레이트의 3상 평형점 (하이드레이트 (H) - 물 (LW) - 기상 (V))을 측정하였다. 기공의 크기가 작아질수록 벌크 상태의 에탄 하이드레이트에 비해 하이드레이트 평형 조건이 온도는 낮아지고 압력이 높아지는 저해효과가 커짐을 알 수 있었다. 천연가스 수송/저장으로의 응용을 고려할 경우 저해효과가 적은 30.0 nm 이상의 실리카 젤을 사용하는 것이 유용할 것으로 사료된다. 본 연구의 결과는 심해저 천연가스 개발, 이산화탄소 심해저장 등의 가스 하이드레이트 응용 연구에도 유용한 기초자료가 될 것이다.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.04a
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• pp.58-58
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• 1994

슬립캐스팅법으로 제조한 튜브형 $\alpha$-알루미나 담체 (평균기공크기 = $0.1 \mum$)에 졸-겔 침지코팅(dipcoating) 또는 가압코팅 (pressurized coating) 법에 의하여 극미세입자 $\gamma$-AlOOH, $TiO_2, SiO_2$, 및 aluminosilicate diphasic 졸을 코팅한 후 300 ~ 500$\circ$C 에서 열처리하여 세라믹 복합막을 제조하였다. 복합막 전체에 대한 균열유무는 $N_2$ 기체투과율의 평균압력에 대한 의존성으로부터 평가하였으며, 한외여과 (ultrafiltration)에의 응용성을 규명하기 위하여 막의 재질 및 제조조건에 따른 polyethylene glycol (PEG) 수용액의 분획분자량 변화를 측정하였다. 합성 세라믹 복합막의 분획분자량 측정 결과 $SiO_2$의 경우 2,000 정도로 매우 우수하였으며 $\gamma-Al_2O_3, TiO_2$, 그리고 aluminosilcate 막들은 6,000 ~ 10,000 범위 값을 갖고 있었다. 또한 막의 기공크기 및 분획분자량을 제어하기 위한 방법으로서 $TiO_2$ 복합막을 300 ~ 700$\circ$C 에서 열처리하였으며 이들에 대한 분획분자량 변화를 비교 분석하였다.