• 식물조직배양학회지
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• 제28권2호
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• pp.109-112
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• 2001

사부에서 사부영역 또는 사공은 원형질 연락사로부터 형성된다. 사공의 형성은 원형질 연락사에 작은 소포체의 융합 또는 새로 형성된 세포벽의 특정한 장소가 먼저 분해된 후 소포체와 세포벽의 융합으로 형성되었거나, 또는 세포질에서 여러개의 작은 소포체들이 원형으로 모여 서로 융합되면서 형성되었다. 소포체들은 세포 내에 산재해 있는 인이나 이질염 색질에서 합성되었다. 조직배양 세포로부터 유도된 사부나 사공은 일반 식물에 존재하는 사부와 마찬가지로 원통모양이었다. 사공이 다양한 방법으로 형성되며, 사공형성에 필요한 재료는 소포체에서 유래되는 것으로 추정된다.

• Journal of Plant Biotechnology
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• 제29권1호
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• pp.41-44
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• 2002

Streptanthus 조직배양 세포에서 유조직 세포로부터 사부 세포의 발달 동안 설탕 운반자는 유도되었고, 단당류인 포도당의 운반자는 사라졌다 (Cho 1998). Streptanthus 조직배양 세포에서 유도된 사부영역과 사공은 sieve endoplasmic reticulum (SER)과 p-protein 합성이 거의 완성되는 시기에 형성되며, SER이 새로 합성된 세포벽을 에워싼 후에 세포벽이 분해되기 시작하였다. 세포벽의 분해와 사공의 형성은 비교적 규칙적으로 진행되었다. 사공의 모양은 계란형이었고, 사공의 외부크기는 세로 1.2 $\mu\textrm{m}$~l.6 $\mu\textrm{m}$, 가로 0.8 $\mu\textrm{m}$~l.3 $\mu\textrm{m}$, 다양하고 사공의 내부크기는 별모양과 유사한 불규칙한 형태였다. 두 사부세포 사이에서 사공의 수는 $\mu\textrm{m}$$^2$당 2개~7개였고, 육상체를 포함한 사공벽에 두께는 0.05 $\mu\textrm{m}$~0.07 $\mu\textrm{m}$,의 두꺼운 벽으로 구성되었다. 사공영역과 사공의 형성에 필요한 에너지는 세포벽 가까이에 위치하고 있는 미토콘드리아에서 얻을 것으로 추측하며, 사공 형성에 대한 SER의 역할은 아직까지 설명할 수 없었다.

• 한국재료학회지
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• 제14권2호
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• pp.157-162
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• 2004

The object of this research is to develop a carbon molecular sieve(below CMS) which can separate selectively to convert mixture gases spout at waste landfill into fuel. And this research is meaningful from the viewpoint of a quality improvement of CH$_4$ gas and an utilization of by-product. CMS was prepared using coconut shell powder as starting material and the effects of activators, temperature and modifier on the reaction were investigated in this research. Also, pore diameter, surface area of CMS and adsorption rate were measured and studied by cahn balance and ASAP2010. Its specific surface area and pore distribution were controlled easily at 800^{\circ}C and adsorption rate was very good. The CMS prepared in this research is shown to be able to separate landfill gases very effectively.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 추계 학술발표회
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• pp.481-489
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• 2006

Two dimensional diffusion model test was conducted to investigate the sedimentation properties and consolidation process of reclaimed ground using dredging coarse soil which is composed of passing amount 20 percentage and 45 percentage of #200 sieve size respectively. The passing amount of #200 sieve size affected on sedimentation properties. The coarse soil which is passing amount of 20 percent showed that the sedimentation structure was layered type and passing amount of 45 percentage was wall-partition type according diffusion distance. Furthermore, the water content of surface and section, and distribution of fine soil were changed according to diffusion distance. and the change amount of pore water pressure and strength property when soil is diffused, segregated and accumulated can be applied efficiently in design of dredging and reclamation.

• 한국해양공학회지
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• 제21권3호
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• pp.26-32
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• 2007

A series of large-scale experiments were carried out in order to examine wave-induced liquefaction in a loosely packed sandbed, its afterward high densification and liquefaction by oscillatory pore pressure. The experiments were conducted in a Large Hydro-Geo Flume that can nearly solve the problems of scale effects of the sandbed, and the 50% sieve diameter of sand was 0.2 mm. The generation of residual pore pressure and its afterward high densification which had observed by Takahashi et al. (1999) in a wave flume experiment using fine sand with the size of 0.08 mm. As a result, the relative density of the sandbed after high densification was increased up to 79% and liquefaction by oscillatory pore pressure was not observed.

• Korean Membrane Journal
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• 제5권1호
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• pp.43-53
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• 2003

The selectivity of a gas in the carbon molecular sieve membrane (CMSM) can be expressed as the ratio of the product of the diffusivity and the solubility of two different gases. The diffusivity is also expressed as the product of the entropy and the total energy (kinetic and potential energy) in the nano-sized pore of the membrane. The present study calculates the entropic-energy and selectivity of penetrant gases such as H$_2$, O$_2$, N$_2$, and CO$_2$ from the gas-in-a box theory to physically analyze the diffusivity of penetrant gas in slit-shaped pore of CMSM focusing on the restriction of gas motion based on the size difference between penetrant gas pairs. The contribution of each energy term is converted to entropic term separately. By the conjugated calculation for each entropic-energy, the entropic effects on diffusivity-selectivity for gas pairs such as H$_2$/N$_2$, CO$_2$/N$_2$, and O$_2$/N$_2$ were analyzed within active pore of CMSM. In the activated diffusion domain, the calculated value of entropic-selectivity lies between 9.25 and 111.6 for H$_2$/N$_2$, between 3.36 and 6.0 for CO$_2$/N$_2$, and between 1.25 and 16.94 for O$_2$/N$_2$, respectively. The size decrement of active pore in CMSM had the direct effect on the reduction of translational entropic-energy and the contribution of vibrational entropic-energy for N$_2$, O$_2$, and H$_2$ was almost negligible. However, the vibrational entropic term of CO$_2$ might extravagantly affect on the entropic-selectivity.

• Parasites, Hosts and Diseases
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• 제27권4호
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• pp.249-252
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• 1989

Fibricola cratera is a strigeoid trematode indigenous to North America that, heretofore, was known only to infect wild mammals. Herein, it is reported that an experimental inoculation of a human volunteer produced a patellt infection that lasted 40 months. Symptoms of epigastric discomfort, loose stools and flatulence occurred over the first year of infection and ameliorated thereafter. Eggs per gram of stool were low (${\leq}2$) throughout the course of infection and were not detected by the standard technique of formalin-ether concentration. To monitor infection, the entire stool sample was examined each month after sieving through No. 10 (pore size 2 mm) and 100 (pore size $145{\;}{\mu\textrm{m}}$) sieves and collecting eggs on a No. 325 (pore size $45{\;}{\mu\textrm{m}}$) sieve. This is the first report of a North American strigeoid trematode capable of maturing in a human and is only the second species of strigeoid known to do so. The other species is F. seoulensis which has been implicated in 26 human infections in Korea.

• Bulletin of the Korean Chemical Society
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• 제26권7호
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• pp.1075-1078
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• 2005

Hydrogen adsorption on various porous materials have been studied with a volumetric method at low temperature in the pressure of 0-760 torr. Their hydrogen uptakes depend at least partly on microporosity rather than total porosity. However, it is also necessary to consider other parameters such as pore size and pore architecture to explain the adsorption capacity. The heat of adsorption and adsorption-desorption-readsorption experiments show that the hydrogen adsorption over the porous materials are composed of physisorption with negligible contribution of chemisorption. Among the porous materials studied in this work, SAPO-34 has the highest adsorption capacity of 160 mL/g at 77 K and 1 atm probably due to high micropore surface area, micropore volume and narrow pore diameter.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3829-3834
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• 2013

$H{\beta}$ (core)/SAPO-11 (shell) composite molecular sieve was synthesized by the hydrothermal method in order to combine the advantages of $H{\beta}$ and SAPO-11 for the methylation of naphthalene with methanol. For comparison, the mechanical mixture was prepared through the blending of $H{\beta}$ and SAPO-11. The physicochemical properties of $H{\beta}$, SAPO-11, the composite and the mechanical mixture were characterized by various characterization methods. The characterization results indicated that $H{\beta}$/SAPO-11 composite molecular sieve exhibited a core-shell structure, with the $H{\beta}$ phase as the core and the SAPO-11 phase as the shell. The pore diameter of the composite was between that of $H{\beta}$ and SAPO-11. The composite had fewer acid sites than $H{\beta}$ and mechanical mixture while more acid sites than SAPO-11. The experimental results indicated that the composite exhibited high catalytic performances for the methylation of naphthalene with methanol.

• 한국물환경학회지
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• 제34권1호
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• pp.84-95
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• 2018

The community structure of benthic macroinvertebrates in the fine sediments of freshwater was analyzed according to various sampling tools and methods. The sediment core with the inner diameter of 7.5 cm was more effective in cost and labor in comparison to that of ${\Phi}5cm$ or ${\Phi}10cm$. The number of species increased with the increase in sample size (replicates). When it was collected five times with the ${\Phi}7.5cm$ sediment core, Shannon-Weaver's diversity and McNaughton's dominance of the sample reached about the 80 % level of the community estimates. Most species appeared in the sediment layer of 0-4 cm, and there were no newly recruited species below the depth of 4 cm. Individual abundance of benthic macroinvertebrates decreased exponentially along with the increase in sediment depth. Compared with the individual abundance of the 0-15 cm sediment layer, the abundance was 60 % in the 0-2 cm layer, 25 % in the 2-4 cm layer, 10 % in the 4-6 cm layer and 95 % in the 0-6 cm layer. Compared with organisms collected with the sieve of 0.2 mm pore, the number of species and the individual abundance sifted through the sieve with pore of 1 mm were 36 % and 88 %, and those with pore of 0.5 mm were 5 % and 55 %, respectively.