• Korean Journal of Plant Tissue Culture
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• v.28 no.2
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• pp.109-112
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• 2001

Sieve element area and sieve pore formed generally from plasmodesmata. Sieve pore formed by the fusion of several tiny vesicles with plasmodesmata, or those with cell wall after the destruction of special region of newly formed cell wall or those finally with circular arranged form from tissure culture of Streptanthus. The tiny vesicles were produced from dispersed nucleolus or heterochromatin. The sieve area and sieve pore formed from tissue cultured cells were shown round tube form similar to those of natural plants. Sieve area and sieve pore were produced by various methods, and it suggested that the basic materials of the construction of sieve pore originated from the vesicles.

• Journal of Plant Biotechnology
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• v.29 no.1
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• pp.41-44
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• 2002

During the phloem development from parenchyma cells in a suspension culture of Streptanthus induced sucrose carrier and glucose carrier disappeared. Sieve element area and sieve pore induced suspension culture of Streptanthus were formed almost at the last period of the synthesis of sieve endoplasmic reticulum (SER) and p-protein. The new synthesized cell wall begann to digeste only after the new cell wall was surrounded by SER. The digested region of the cell wall and the formed region of sieve pore were regular comparatively. The completed sieve pore was an oval form, and the outer portion of sieve pore varied, ca 1.2 ${\mu}{\textrm}{m}$~1.6 ${\mu}{\textrm}{m}$ in longitudinal, 0.8 ${\mu}{\textrm}{m}$~1.3 ${\mu}{\textrm}{m}$ in tangential, and the inner size of sieve pore was irregular form of a star-like shape. The number of sieve pore between sieve cells was ca 2~7 per ${\mu}{\textrm}{m}$$^2$ and the sieve pore wall with callose was 0.05 ${\mu}{\textrm}{m}$~0.07 ${\mu}{\textrm}{m}$ in thickness. The energy for the formation of sieve element area and sieve pore might be supplied by mitochondria near the new cell wall and the role of SER remains to be illucidated.

• Korean Journal of Materials Research
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• v.14 no.2
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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.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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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.

• Journal of Ocean Engineering and Technology
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• v.21 no.3 s.76
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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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• v.5 no.1
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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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• v.27 no.4
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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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• v.26 no.7
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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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• v.34 no.12
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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.

• Journal of Korean Society on Water Environment
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• v.34 no.1
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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.