• Journal of Surface Science and Engineering
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• v.12 no.2
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• pp.75-83
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• 1979

The Rates of formation and heats of activation for the intermatallic Compound Layers between Cold rolled sheet and molten aluminium &ath (adding small amounts of silicon) has been determined by Continous aluminizing method in the temperature range of 680$^{\circ}$ to 760$^{\circ}C$ and with immerssion time. The structure of the intermetallic Compound Layers was the shape of "Tongues" in pure Al-Bath and Al-Bath Containing 1% Si, But in Al-5% Si Bath was "Band" the Composition of the intermetallic Compound Layers were checked by microhardness measurements and X-Ray probe micro analyzer. FeAl intermetallic Compound layer was found to be uniform in pure Al-Bath and Al-5% Si Bath, But Fe Al intermetallic Compound Layer was shown in Al-1% Si Bath. The growth Rates of the intermetallic Compound Layers was most rapidly increased at Temperatures from 720$^{\circ}$ to 760$^{\circ}C$, at the immorsion time above 60 Second in pure Al-Bath, But in Al-1% Si Bath was solwly increased for the same conditions, and then in Al-5% Si Bath was hardly effected by these experimental condition. Heasts of activation of 29, 46 Kcal per mole which calculuted from Layer growth experiments were found in pure Al-Bath, Al-1% Si Bath respectively.

• Korean Journal of Materials Research
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• v.11 no.7
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• pp.615-621
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• 2001

We carried out the kinetic model calculations in order to estimate the nucleation rates for two kinds of half-loop dislocations in highly strained hetero-epitaxial growths; $60^{\circ}$dislocations and twinning dislocations. The surface defects and the stress concentration effects were considered in this model, and the remaining elastic strain of the epilayers with increasing film thickness was taken into account by using the modified Matthews' relation. The calculations showed that the stress concentration effect at surface imperfections is very important for describing the defect generation in highly mismatched epitaxial growth. This work also showed that the stress concentration effect determined the type of dislocation nucleating dominantly at early growth stages in accordance with our XTEM (cross-section transmission electron microscopy) defect observation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.80-104
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• 1996

The development of routine techniques for the isolation and in vitro maintenance of conducting airway epithelial cells in a differentiated state provides an ideal model to study the factors involved in the regulation of the expression of mucocilicary differentiation. Several key factors and conditions have been identified. These factors and conditions include the use of biphasic culture technique to achieve mucociliary differentiation and the use of such stimulators, the thickness of collagen gel substratum, the calcium level, and vitamin A, and such inhibitors, the growth factors EGF and insulin, and steroid hormones, for mucous cell differentiation. Using the defined culture medium, the life cycle of the mucous cell population in vitro was investigated. It was demonstrated that the majority of the mucous cell population in primary cultures is not involved in DNA replication. However, the mucous cell type is capable of self-renewal in culture and this reproduction is vitamin A dependent. furthermore, differentiation from non-mucous cell type to mucous cell type can be demonstrated by adding back a positive regulator such as vitamin A to the “starved” culture. Cell kinetics data suggest that vitamin A-dependent mucous cell differentiation in culture is a DNA replication-independent process and the process is inhibited by TGF-${\beta}$1.

• BMB Reports
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• v.39 no.4
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• pp.394-399
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• 2006

The transport of putrescine into a moderately salt tolerant cyanobacterium Synechocystis sp. PCC 6803 was characterized by measuring the uptake of radioactively-labeled putrescine. Putrescine transport showed saturation kinetics with an apparent $K_m$ of $92{\pm}10\;{\mu}M$ and $V_{max}$ of $0.33{\pm}0.05\;nmol/min/mg$ protein. The transport of putrescine was pH-dependent with highest activity at pH 7.0. Strong inhibition of putrescine transport was caused by spermine and spermidine whereas only slight inhibition was observed by the addition of various amino acids. These results suggest that the transport system in Synechocystis sp. PCC 6803 is highly specific for polyamines. Putrescine transport is energy-dependent as evidenced by the inhibition by various metabolic inhibitors and ionophores. Slow growth was observed in cells grown under salt stress. Addition of low concentration of putrescine could restore growth almost to the level observed in the absence of salt stress. Upshift of the external osmolality generated by either NaCl or sorbitol caused an increased putrescine transport with an optimum 2-fold increase at 20 mosmol/kg. The stimulation of putrescine transport mediated by osmotic upshift was abolished in chloramphenicol-treated cells, suggesting possible involvement of an inducible transport system.

• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.447-454
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• 2009

The transport of spermidine into a cyanobacterium, Synechocystis sp. pec 6803, was characterized by measuring the uptake of $^{14}C$-spermidine. Spermidine transport was shown to be saturable with an apparent affinity constant ($K_m$) value of $67{\mu}M$ and a maximal velocity ($V_{max}$) value of 0.45 nmol/min/mg protein. Spermidine uptake was pH-dependent with the pH optimum being 8.0. The competition experiment showed strong inhibition of spermidine uptake by putrescine and spermine, whereas amino acids were hardly inhibitory. The inhibition kinetics of spermidine transport by putrescine and spermine was found to be noncompetitive with $K_i$ values of 292 and $432{\mu}M$, respectively. The inhibition of spermidine transport by various metabolic inhibitors and ionophores suggests that spermidine uptake is energy-dependent. The diminution of cell growth was observed in cells grown at a high concentration of NaCl. Addition of a low concentration of spermidine at 0.5 mM relieved growth inhibition by salt stress. Upshift of the external osmolality generated by either NaCl or sorbitol caused an increased spermidine transport with about 30-40% increase at 10 mosmol/kg upshift.

• Proceedings of the Membrane Society of Korea Conference
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• 2002.05a
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• pp.81-85
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• 2002

Small angle light scattering and field emission scanning electron microscope have been used to quantify the kinetics of liquid-liquid separation behavior during water vapor(RH52%[$\pm$3%] at 27$^{\circ}C$) quenching (non-solvent induced phase separation, NIPS) of polysulfone/NMP/Alcohol and CPVC/THF/Alcohol, respectively. Time dependence of the position of the light scattering maximum was observed at polysufone dope solutions, confirming spinodal secomposition (SD). while CPVC dope solutions showed a decreased scattered light intensity with a increased q-valuel, indicating nucleation & growth (NG). For the each system, domain growth rate in the intermediate and late stage of phase separation decreased with increasing the number of carbon of alcohol used as additive (non-solvent). Also, in the early stage for SD, the scattering intensity with time was in accordance with Cahns linear theory of spinodal decomposition,[1-3] regardless of types of non-solvent additive.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.463-466
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• 2000

In this study, it was observed to oxygen uptake rate(OUR) on microbes in activated sludge process. OUR was showed to 43, 55, and $64\;mgO_2/L/hr$ when inoculated microbes mass were 3, 5, and 10%(v/v%). In additon to oxygen was consumed to $4{\sim}42\;mgO_2/L/hr$ as changed substrate concentration. Also, we were measured kinetics coefficient in order to know growth tendency. It was concluded to maximum growth rate$(\;{\mu}\;_{max})$, $2.7\;day^{-1}$, yield coefficient, 0.655, and half-velocity coefficient, 36.11 mg/L.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.3
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• pp.99-104
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• 2003

Alumina/zirconia-glass composites prepared by melt-infiltration were investigated to evaluate the influence of zirconia addition on mechanical and optical properties of the composites and glass penetration kinetics. The infiltration distance was parabolic with respect to time as described by the Washburn equation and the penetration rate constant, K, decreased due to the reduction In pore size as the amount of zirconia rose. The zirconia addition increased lightness ($L^*$) but reduced K, transmittance and color sharpness ($C^*$) It can be concluded that the zirconia addition was not effective to the mechanical properties of the composites due to the increase in porosity even though the toughness of the composites increased when zirconia was added up to 15 wt%.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2404-2412
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• 1994

A mathematical model has been developed for predicting kinematic, thermal, and solidification histories of atomized droplets during flight. Liquid droplet convective cooling, recalescence, equilibrium-state solidification, and solid-phase cooling were taken into account in the analysis of the solidification process. The spherical shell model was adopted where the heterogeneous nucleation is initiated from the whole surface of a droplet. The growth rate of the solid-liquid interface was determined from the theory of crystal growth kinetics with undercooling caused by the rapid solidification. The solid fraction after recalescence was obtained by using the integral method. The thermal responses of atomized droplets to gas velocity, particle size variation, and degree of undercooling were investigated through the parametric studies. It is possible to evaluate the solid fraction of the droplet according to flight distance and time in terms of a dimensionless parameter derived from the overall energy balance of the system. It is also found that the solid fraction at the end of recalescence is not dependent on the droplet size and nozzle exit velocity but on the degree of subcooling.

• The Journal of Korean Society of Virology
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• v.28 no.2
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• pp.139-146
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• 1998

Recombinant polioviruses have been developed by many research groups for use as vaccine vector because poliovirus induces mucosal immunity as well as humoral immunity through oral uptake. We assessed the potential use of poliovirus as a T-cell epitope carrier. Recombinant poliovirus V129 5L was constructed to have a substituted T-helper epitope from the core protein of Hepatitis B virus at neutralization antigenic site 1 on its VP1 capsid protein. The recombinant virus replicated less efficiently than type 1 poliovirus Mahoney strain. The V129 5L formed a little smaller plaques than the Mahoney strain and showed some 1.25 log unit lower titer at the peak in the one-step growth kinetics though it had similar growth profile to that of the Mahoney strain. Since V129 5L recombinant virus was genetically stable even after 24 successive passages in HeLa cells, the antigenic site 1 on VP1 capsid protein was confirmed for its ability of carrying T cell epitope. The genetic stability of V129 5L also indicated that recombinant poliovirus can be successfully utilized for the development of the multivalent vaccines.