• Journal of the Korean Chemical Society
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• v.7 no.1
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• pp.47-50
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• 1963

The effect of the pulsation on the particle hold-up in a pulsed wetted column has been studied theoretically for the case of laminar region and experimentally for the cases of transient and turbulent regions. The experiment has been carried out by employing water as fluid medium and solid particles. The pulsation has been given by the reciprocating motion of a piston. The results of the investigation show that the pulsation would not give apparent effect on the particle hold-up but would increase the total travelling length of the particle.

• Interaction and multiscale mechanics
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• v.3 no.1
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• pp.81-94
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• 2010

The steady state response of a rotating generalized thermoelastic solid to a moving point load has been investigated. The transformed components of displacement, force stress and temperature distribution are obtained by using Fourier transformation. These components are then inverted and the results are obtained in the physical domain by applying a numerical inversion method. The numerical results are presented graphically for a particular model. A particular result is also deduced from the present investigation.

• Structural Engineering and Mechanics
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• v.56 no.3
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• pp.341-354
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• 2015

The dual-phase lag heat transfer model is employed to study the problem of isotropic generalized thermoelastic medium with internal heat source. The normal mode analysis is used to obtain the exact expressions for displacement components, force stress and temperature distribution. The variations of the considered variables through the horizontal distance are illustrated graphically. The results are discussed and depicted graphically.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.890-893
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• 2012

Gas hydrates are solid crystal structures formed by enclathration of gaseous guest species into 3-dimensional lattice structure of hydrogen-bonded water molecules. These compounds can be potentially used as an energy storage/transportation medium because they can hold a large amount of gas in a small volume of the solid phase. In addition, huge amount of natural gas, buried in seabeds or permafrost region in the form of the solid hydrate, is regarded as a future energy source. In this study, synthesized natural gas, whose composition is 90.0 mol% of methane, 7.0 mol% of ethane, and 3.0 mol% of propane, was used to identify formation behaviors of natural gas hydrates for the purpose of applying the gas hydrate to a storage/transportation medium of natural gas. According to the experimental results obtained by means of the solid-state NMR and high-resolution powder XRD methods, it is found that formed natural gas hydrates have crystal structure of the structure-II hydrate, and that methane occupies both small and large cages, while the others only occupy large ones. In addition, both the NMR spectroscopy and the gas chromatograph showed that there exists preferential occupation among the natural gas components during the hydrate formation. Compositional changes after the hydrate formation revealed that the preferential occupation is in order of propane, ethane, and methane (propane is the most preferential guest species when forming natural gas hydrates).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.237-241
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• 2006

This experiment was carried out comparison with haploid plants productivity by microspore culture among domestic cultivars of Brassica napus L. Isolated microspore from flower buds were cultured on NLN medium supplemented with 13% sucrose, $0.05mg/{\ell}$ BA and $0.5mg/{\ell}$ NAA. Genotype was important factor in haploid embryo productivity 'Tamlayuchae' showed the highest haploid embryo production frequency (176 embryos formed from 1 flower bud). But, 'Hallayuchae' and 'Youngsanyuchae' were not generated embryo even cell division. When suspension culture on NLN liquid medium at 100 rpm, embryos were developed multilobe abnormal embryo cluster. Multilobe abnormal embryos on MS medium basal solid medium were regenerated multiple shoots. Regenerated haploid plant with well developed shoots and roots on MS basal medium were successfully transferred to pots.

• Tunnel and Underground Space
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• v.13 no.1
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• pp.20-32
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• 2003

To understand the behavior of migration of contaminants in a fractured porous medium is a key to assure the overall safety of a potential radwaste repository. The feasible retention mechanism of contaminant transport in a tinctured medium are sorption of contaminants on solid surface and matrix diffusion of contaminants from a fracture into an adjacent porous medium. The acceleration mechanisms are the migration of contaminants in the form of pseudo-colloids and the limit of a volume f3r matrix diffusion. In this paper, the effects of these two acceleration mechanisms are studied mathematically, then semi-analytically computed by the application of the Talbot theorem and verified. Results indicate that the acceleration processes cannot be neglected in the modeling of contaminant transport in a fractured porous medium.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.86-92
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• 2013

In studies on an alternative insulating gas of $SF_6$ gas, the section of the alternative gas and an insulation technique to improve its low dielectric strength have been reported, but very few attempts have been made at the dependence of a gas pressure and a gap as well as the medium effect in the alternative gas. The purpose of this paper is to analyze the dependence of the gas pressure and the gap at surface flashover voltage in dry air. The dependence is analyzed based on the medium effect. The medium effect by the gas pressure and the gap can be explained by surface roughness of a solid dielectric and an electrode as well as an electric field which decreases due to the correlation between the collision ionization coefficient and the gap, respectively. In addition, an insulation technique which can fabricate a compact eco-friendly gas insulated switchgear is proposed by the results of this paper.

• Biomedical Science Letters
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• v.19 no.1
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• pp.41-47
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• 2013

Pluripotent stem cells (PSCs) have lots of potential in biomedical sciences owing to its potential to differentiate into any kind of cells in the body. However, it is still a challenge to culture PSCs on a large scale for application to regenerative medicine. Herein, we introduce a synthetic polymer that enables large-scale suspension culture of human PSCs. By employing suspension culture, it became unnecessary to use conventional substrata such as mouse embryonic fibroblast (MEF) or Matrigel$^{TM}$, which are believed to be main causative sources of xenogeneic contamination in cultured human PSCs in vitro. Human PSCs were cultured in the medium in which elastin-like polypeptide (ELP) dissolved. The ELP in the medium became harden as temperature increases by transforming the medium into a semi-solid gel that supported growth of human PSCs in suspension. Gel-sol transition temperature of ELP can be adjusted by modifying the peptide sequence in which 5 amino acids, Val-Pro-Gly-Xaa-Gly, repeated sequentially. We constructed 3D suspension media having transition temperature around $33{\sim}35^{\circ}C$ using an ELP consisted of 40, 60, or 80 repeats of a monomer, which was Val-Pro-Gly-Val-Gly. Among the ELPs, ELP80 was chosen as the best ELP to support growth of human PSCs in suspension culture. This result suggests that the ELP80 can be a medium component for culturing human PSCs in large-scale.

• Korean Journal of Plant Tissue Culture
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• v.27 no.6
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• pp.447-451
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• 2000

This study was conducted to establish a regeneration system of plantlets through callus culture induced from bulb scales of Lillium‘Gelria’. Friable callus was induced very easily from bulb scales, and grew vigorously on medium lacking growth regulators. In media with 0.5∼ 1.0 mg/L kinetin and 0.1 ∼ 1.0 mg/L NAA, 100% of explants produced callus. Proliferation of callus was actively occurred on media containing 0.1 ∼ 1.0 mg/L kinetin and 0.1 ∼ 1.0 mg/L NAA. Callus proliferation and regeneration of bulblets from callus were occurred simultaneously. Light condition was more effective for the callus proliferation and solid medium was better than liquid medium. Althrough callus was proliferated vigorously on media containing 0.1 ∼ 1.0 mg/L BA and NAA, the frequncy of plantlet regeneration was better on medium without growth regulators, then on medium with 0.1 mg/L BA and NAA.

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.719-725
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• 2009

This study was conducted to establish the optimal condition for acclimatization from somatic embryos of Eleutherococcus seoulensis. Torpedo-shaped embryos of Eleutherococcus seoulensis were cultured on 1/3 MS and WPM media supplemented with $GA_3$ (3.0, 5.0 mg/L) for 4 weeks. Plentlets were transferred to 1/2 SH solid medium with 1.0 mg/L $GA_3$ and 0.2% activated charcoal for shoot and root elongation and them elongated plantlets further developed on 1/2 SH medium for 4 weeks. Developed plantlets further elongated into well-shaped leaf and root system on 1/3 SH medium under ventilation condition for 4 weeks. Plantlets grew normally on 1/3 SH basal medium, were acclimated on various soil. Survival frequency of plantlets was influenced by soil type(peatmoss+perlite, perlite, soil on Nam mountain). The highest survival rate to soil was more than 70% when plantlets were 1/3 SH medium under ventilation condition in Nam mountain soil. These results indicate that the systematic procedure of plant production in Eleutherococcus seoulensis could be practically applicable for mass propagation.