• 지질공학
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• 제24권2호
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• pp.179-189
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• 2014

We analyzed the three-dimensional distribution of micropores and internal structures in both fresh and weathered granite using micro-focus X-ray computed tomography (micro-CT). Results show that the pore radius in fresh granite is mostly in the range of $17-50{\mu}m$, the throat radius is in the range of $5-25{\mu}m$, and the coordination number (CN) of pores is less than 10. In contrast, the pore radius in weathered granite is mostly in the range of $20-80{\mu}m$, the throat radius is in the range of $8-30{\mu}m$, and the CN is less than 12. In general, a positive linear relationship exists between pore radius and CN. In addition, both the size and the density of pores increase with an increasing degree of rock weathering. The size of the throats that connect the pores also increases with an increasing degree of weathering, which induces fracture propagation in rocks. Micro-CT is a powerful and versatile approach for investigating the three-dimensional distributions of pores and fracture structures in rocks, and for quantitatively assessing the degree of pore connectivity.

• 한국연초학회지
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• 제10권1호
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• pp.75-82
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• 1988

Cigarettes were made using a triple filter with several porous materials in its cavity. The removal effect of the adsorbents on carbon monoxide and hydrogen cyanide in cigarette smoke was investigated with the variation of their surface area and pore volume distributions. Several attempts were made to activated coconut shell based char under the fixed steam purging rate. 1. The specific surface area increased in number of micropore. It was found for transitional pore to have a little effect on the total surface area. 2. A Small amount of the particulate matter adsorbed on the adsorbents with transitional pores, Zeolite showed a little effect on the carbon monoxide adsorption though its small pore volume, but there was no significant difference in the adsorption capacity zeolite and the others. 3. In the adsorption for hydrogen cyanide as a vapor phase in cigarette smoke, the adsorption effect of the adsorbents increased remarkably with increasing their surface area and number of micropore. It was considered that the adsorbents with small pore volume like molecular seive 4A, in which the capillary diffusion of adsorbates could not be able, would not be effective for the adsorption of hydrogen cyanide.

• 한국터널지하공간학회 논문집
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• 제6권1호
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• pp.41-50
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• 2004

본 논문에서는 기존댐 인접지에 터널구조물을 건설하기 위한 발파시, 폭괴하중으로 인한 지반진통이 댐 제체와 간극수암에 마치는 영향을 고찰하였다. 댐의 안정성 검토는 발파시 발생하는 코어부의 최대입자속도 (Peak Particle Velocity)를 계산하여 수행하였다. 간극수와 지반진동간의 상호 연계해석을 위하여 댐 제체에 대한 정상상태 흐름해석을 수행하여 간극수압 분포를 파악하고, 유발된 과잉간극수암 및 유효응력분포로 발파하중이 인접지반에 미치는 영향을 분석하였다. 또한 발파와 같은 급속하중 재하 후 과잉간극수압의 증가 및 소산현상 해석을 위하여 Finn & Byrne Model을 적용하여 하중재하 전후의 유효응력 변화양상을 검토하였다.

• 한국재료학회지
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• 제28권1호
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• pp.50-61
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• 2018

Various carbon aerogels (CAs) were prepared from polymerization of resorcinol and formaldehyde and applied as the electrode materials of an electric double layer capacitor (EDLC) with the aim of controlling the textural and electrochemical properties of CAs by the type of base catalyst and the ratio of resorcinol to catalyst (R/C). The CAs from $NaHCO_3$ and $KHCO_3$ with $H^+$ ions had higher specific surface areas but exhibited lower electrochemical properties than those from $K_2CO_3$ and $Na_2CO_3$, which had more uniform pore size distributions. The electrochemical properties of $Na_2CO_3$ were superior to those of $K_2CO_3$ probably because the polarizing power of $Na^+$ ions was higher than $K^+$ ions. With an increasing R/C ratio, the pore sizes of CA showed a tendency to increase but the uniformity of the pore size distribution got worse. For the four base catalysts, the highest electrochemical property was obtained at the R/C ratio of 500.

• 한국세라믹학회지
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• 제23권5호
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• pp.93-101
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• 1986

Microporous glasses were prepared from the 50 $SiO_2-44$ $B_2O_3-6$ $Na_2O$(wt%) parent glass by the phase eparation technique and were characterized by SEM, BET, and Gas Adsorption methods to investigate the possiblity of their use as salt-rejection membranes for reverse osmosis. The conditions of the phase separation for the possible glass membranes were optimized for the given parent glass. The temperature and duration of heat-treatment were desired to be lower(853K) and shorter (1/2~1 hr) respectively. The specific surface areas of porous glasses prepared in this study were about 80~120$m^2$/g and their pore size distribution had a unimodal shape(peak pore radius less than 15$\AA$) It was suggested that the porous glass obtained in this work could be effective for salt-rejection in point of pore size distributions but the way to increase its surface area for the high flux must be studied.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2003년도 춘계학술발표대회 요약집
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• pp.224.2-224.2
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• 2003

• 한국토양비료학회지
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• 제48권5호
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• pp.351-360
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• 2015

Human influence on soil formation has dramatically increased with human civilization and industry development. Increase of anthropogenic soils induced researches on the anthropogenic soils; classification, chemical and physical characteristics of anthropogenic soils and plant growth from anthropogenic soils. However there have been no comprehensive analyses on soil pore or physical properties of anthropogenic soils from 3 dimensional images in Korea. The objectives of this study were to characterize physical properties of anthropogenic paddy field soils by depth and to find differences between natural and anthropogenic paddy field soils. Soil samples were taken from two anthropogenic and natural paddy field soils; anthropogenic (A_c) and natural (N_c) paddy soils with topsoil of coarse texture and anthropogenic (A_f) and natural (N_f) paddy soils with topsoil of fine texture. The anthropogenic paddy fields were reestablished during the Arable Land Remodeling Project from 2011 to 2012 and continued rice farming after the project. Natural paddy fields had no artificial changes or disturbance in soil layers up to 1m depth. Samples were taken at three different depths and analyzed for routine physical properties (texture, bulk density, etc.) and pore properties with computer tomography (CT) scans. The CT scan provided 3 dimensional images at resolution of 0.01 mm to calculate pore radius size, length, and tortuosity of soil pores. Fractal and configuration entropy analyses were applied to quantify pore structure and analyze spatial distribution of pores within soil images. The results of measured physical properties showed no clear trend or significant differences across depths or sites from all samples, except the properties from topsoils. The results of pore morphology and spatial distribution analyses provided detailed information of pores affected by human influences. Pore length and size showed significant decrease in anthropogenic soils. Especially, pores of A_c had great decrease in length compared to N_c. Fractal and entropy analyses showed clear changes of pore distributions across sites. The topsoil layer of A_c showed more degradation of pore structure than that of N_c, while pores of A_f topsoil did not show significant degradation compared with those of N_f. These results concluded that anthropogenic soils with coarse texture may have more effects on pore properties than ones with fine texture. The reestablished paddy fields may need more fundamental remediation to improve physical conditions.

• 대한화학회지
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• 제16권6호
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• pp.341-348
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• 1972

질소의 흡착 등온곡선을 이용하여 흡착체의 동공부피 분포를 계산하는 과정에서 표면장력의 곡률 의존도 고려 효과를 조사하였다. 즉, 장세헌 등에 의한 표면장력의 곡률 의존도식과 캘빈 식으로부터 주어진 압력에서의 캘빈반경을 구하고, 이것으로부터 흡착체의 동공부피 분포를 계산하였다. 이와 같이하여 얻은 계산 결과를 표면장력의 곡률 의존도를 고려하지 아니한 종래방법에 의한 계산 결과와 비교하였다. 일반적으로 곡률 의존도를 고려해주면 동공부피 분포 곡선의 극대부분이 큰 동공 쪽으로 이동한다. 또한 모세관 응축이 일어나는 상대압력이 종래까지 생각했던 것보다 훨씬 낮아지고 있다. 이러한 효과들은 흡착체의 동공들이 미세해 질수록 더욱 현저하게 일어난다.

• 공업화학
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• 제9권5호
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• pp.615-618
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• 1998

수성 교질법에 의한 제올라이트 합성 과정에서 활성탄을 부가함으로써 제올라이트 결정화 과정에 미치는 영향과 활성탄 기공 내에서의 제올라이트 결정의 담지현상을 조사하였다. A형 제올라이트를 합성하기 위한 몰 조성비로 조절된 알루미노 실리케이트 겔상에 5 wt % 정도의 활성탄을 첨가할 경우에는 그대로 A형 제올라이트가 생성되었으나 15 wt % 정도 첨가할 경우에는 대부분이 X형이고 일부 A형과 P형 제올라이트가 혼재된 상태로 결정화가 일어났으며, 20 wt %이상 첨가할 경우에는 순수한 X형 제올라이트가 생성되었다. 활성탄의 기공 입구와 내부에는 $1{\mu}m$ 이하의 미세한 제올라이트 결정들이 서로 엉겨붙어 있는 형태로 관찰되었으며, 기공분포 및 입도분포 결과로부터 단순히 제올라이트와 활성탄의 혼합물 형태가 아니라 활성탄 기공 내에 미세한 제올라이트 결정들이 담지되어 있는 복합 소재임을 확인하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.427-434
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• 2000

Hydraulic conductivity of soil-cement was measured as a function of some selected construction variables that are often encountered in practice. They are initial (or compaction) water content, delayed compaction after mixing, and repeated freezing and thawing. Sandy and clayey soils were used. The hardening agent used was a cement based soil stabilizer consisting of 80% of ordinary Portland cement and 20% of a combination of supplementary materials. Hydraulic conductivity of soil-cement with varying initial water content was, in trend, similar to that of compacted clay. Hydraulic conductivity of soil-cement decreased with increasing initial water content and reached its minimum when compacted wet of optimum water content. Pore size distributions of soil cement at different initial water contents were analyzed using mercury intrusion porosimetry. The analysis showed that dryer condition led to the formation of larger pores with lesser total pore volume; smaller pores with larger total pore volume at wetter condition. Hydraulic conductivity of soil-cement increased by orders in magnitude when specimen underwent delayed compaction of longer than 4 hours after mixing and repeated freezing and thawing.