• The Korean Journal of Ecology
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• v.26 no.6
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• pp.307-312
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• 2003

To study the diversity of heterotrophic bacteria isolated from intestine of starfish, Asterias amurensis, we collected starfishes from the coastal area near Jangheung-Gun, Jeollanam-Do, Korea during July, 2000. Population density and bacterial diversity in the intestine of starfish were measured. The results were as follows; The population densities of heterotrophic bacteria in the intestine of starfish were 8.65${\pm}$0.65${\times}10^3\;dfu\;g^{-1}$. Gram positive bacteria occupied 59% among 29 isolates. The community structure of dominant heterotrophic bacteria in the intestine of starfish consisted of Bacillaceae in the low G+C gram positive bacteria subphylum, Microbacteriaceae in the high G+C gram positive bacteria subphylum, and Alteromonadaceae in ${\gamma}$-Proteobacteria subphylum. Among eight strains of Bacillus spp., three strains showed more than 97% identity, but five strains showed about 90% identity with type strain on the basis of partial 16S rDNA sequence.

• IMMUNE NETWORK
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• v.3 no.2
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• pp.156-163
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• 2003

Background: $\beta$-1,3-glucans are well known to enhance the immune reactions, resulting in antitumor, antibacterial, antiviral, anticoagulatory and wound healing activities. $\beta$-1, 3-glucans have various activities depending on molecular weight, degree of branching, conformation, water-solubility and intermolecular association. However, the $\beta$-1,3-glucan linked backbone structure is essential and $\beta$-D-glucopyranosyl units are required for immuno-potentiating activities. Result: In this study, we tested the immunophamacological activities of soluble $\beta$-1,3-glucans and confirmed the following activities: (1) $IFN-{\gamma}$ production in PBMCs in the presence or the absence of PHA, LPS, or IL-18; (2) induction of various cytokines in the spleen and thymus; (3) adjuvant effect on the antibody production; (4) nitrogen oxide synthesis in macrophages; (5) the cytotoxic and antitumor effects on cell lines and ICR mice. Conclusion: These results strongly suggested that $\beta$-1,3-glucans possessed various immuno-pharmacological activities.

• Journal of Korean Academy of Nursing
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• v.24 no.4
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• pp.666-677
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• 1994

In comparison with the long and continuous his-tory of research in the general area of stress and coping, theoretical and clinical interest in family stress and adaptation is a recent phenomenon. To understand the phenomena of family behavior, a comprehensive theoretical framework is needed to us provide an adequate background to for research. This study was designed to develop and test a hypothetical model for family stress and adaptation in families with handicapped children. A hypothetical model was constructed on the basis of the family stress theory developed by McCubbin etc. The model included six paths. For the purpose of model testing, empirical data was collected from May to August, 1992. The subjects of the study were 190 parents of chidren in five special schools and one private institute in Seoul and Choong Nam. An SPSS P $C^{+}$ and PC-LISREL 7.13 computer programs were used for descriptive and covariance structure analysis. The results of the study are as follows. (1) Family Stress(${\gamma}$$_{3l}$=-.288, T=-4.942) had a direct effect on Family Adaptation. (2) Family Functioning ($\beta$$_{21}$=-.373, T=5.595) had a direct effect on Situational Definition. (3) Family Functioning ($\beta$$_{31}$ =.334, T=5.375) had a direct effect on Family Adaptation. (4) Situational Definition( a2=.270, T=4.285) had a direct effect on Family Adaptation The model was supported by the empirical data. Thus it is suggested that the model could be adequately applied to family nursing care of families with a mentally handicapped child. In particular, the nursing interventions that enhance family functioning and the situational definition would improve family adaptation in families with mentally handicapped children.n.n.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.5
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• pp.229-234
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• 2017

In this study, TiAl alloy was fabricated by a centrifugal casting method for turbo charge of automotive. Optimum conditions for defectless morphology using various ceramic mold were investigated. The crystal structure, microstructure, and chemical composition of the TiAl prepared by centrifugal casting were studied by X-ray diffractometer (XRD), optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS), microvickers hardness analyzer (HV). Two kinds of dendrite structures were observed with 4-fold and 6-fold symmetries. The FE-SEM, EDS and HV examinations of the as-cast TiAl showed that the thickness of the oxide layer (${\alpha}$-case) was typically less than $50{\mu}m$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.226-229
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• 2004

A stoichiometric mixture of evaporating materials for $CuAlSe_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CuAlSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $680^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuAlSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.24{\times}10^{16}\;cm^{-3}$ and $295\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuAlSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;=\;2.8382\;eV\;-\;(8.68{\times}10^{-4}\;eV/K)T^2/(T+155K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $CuAlSe_2$ have been estimated to be 0.2026 eV and 0.2165 eV at 10K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $CuAlSe_2$. The three photocurrent peaks observed at 10K are ascribed to the $A_1-$, $B_1-$, and $C_1$-exciton peaks for n = 1.

• Journal of Mechanical Science and Technology
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• v.19 no.11
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• pp.2032-2039
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• 2005

The lattice Boltzman method (LBM) and the finite difference-based lattice Boltzmann method (FDLBM) are quite recent approaches for simulating fluid flow, which have been proven as valid and efficient tools in a variety of complex flow problems. They are considered attractive alternatives to conventional finite-difference schemes because they recover the Navier-Stokes equations and are computationally more stable, and easily parallelizable. However, most models of the LBM or FDLBM are for incompressible fluids because of the simplicity of the structure of the model. Although some models for compressible thermal fluids have been introduced, these models are for monatomic gases, and suffer from the instability in calculations. A lattice BGK model based on a finite difference scheme with an internal degree of freedom is employed and it is shown that a diatomic gas such as air is successfully simulated. In this research we present a 2-dimensional edge tone to predict the frequency characteristics of discrete oscillations of a jet-edge feedback cycle by the FDLBM in which any specific heat ratio $\gamma$ can be chosen freely. The jet is chosen long enough in order to guarantee the parabolic velocity profile of a jet at the outlet, and the edge is of an angle of $\alpha$=23$^{o}$. At a stand-off distance w, the edge is inserted along the centerline of the jet, and a sinuous instability wave with real frequency is assumed to be created in the vicinity of the nozzle exit and to propagate towards the downstream. We have succeeded in capturing very small pressure fluctuations resulting from periodic oscillation of the jet around the edge.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.235-243
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• 2020

Lumbar Lordosis Angle (LLA) is an index that can be used to evaluate the curvature of the lumbar vertebrae. It can measure the structural stability of the lumbar spine and the stability of each segment of the vertebral column at the intervertebral disc angle (IDA). Especially, our data shows it is found to be a strong positive correlation between obesity and the angle of lordosis for lumbar vertebrae. Also, the reason for the large IDA in the case of obesity seems to be the result of the weakening of anatomical structure as well as the gravity effect. And, the obesity interferes with normal sagittal balance and fails to maintain a straight posture with minimal energy. Therefore, the obesity can be an important factor in causing back pain by changing the lumbar lordosis.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.6
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• pp.761-769
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• 1999

In this paper the effect of aging heat treatment to the Corrosion behavior for the Nimonic 80A superalloy was studied by AC Impedance methods. Tested solution was 3.5% with tempera-ture $25^{\circ}C$ Electro-chemical corrosion test were carried out for the Nimonic 80A super-alloy which solution heat treated at $1080^{\circ}C$ for 8 hours followed by aging heat treated at $650^{\circ}C,\;700^{\circ}C,\;750^{\circ}C\;800^{\circ}C$ and $850^{\circ}C$ with 16hours under vacuum environment. The obtained results were as follows; 1. Base metal and solution-treated materials were exhibited similar corrosion tendency as Ran-dle equivalent cell. The value of passive film resistance was 579 ohms for the base metal and 124,770 ohms for the solutionized metal such a difference was arose by the ${{\gamma}_^'}$ precipitate on the metal surface during heat treatment. 2. The measure value of $R_p$ for heat-treated at $650^{\circ}C,\;700^{\circ}C,\;800^{\circ}C$and $850^{\circ}C$ were 97,943, 93, 111, 26,961, 15,798 and 11,780ohm respectively. Which indicated that the passive film resistance Rp was reduced as aging temperature increased due to the growth of grain size and sensitization at the grain boundary. 3. The similar tendency was exhibited for corrosion behavior of the electro-chemical corrosion polarization method and AC impedance method and confirmed that AC impedance method was useful tool for corrosion research.

• Korean Journal of Poultry Science
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• v.35 no.1
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• pp.39-55
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• 2008

Like the other herpesviruses, the virion of MDV consists of an envelope, which surrounds an amorphous tegument. Within the tegument, and icosahedral capsid encloses a linear double-stranded DNA core. Although the genome structure of MDV indicates that it is an ${\alpha}-herpesvirus$ like herpes simplex and varicella-zoster viruses, biological properties indicate MDV is more akin to the ${\gamma}-herpesvirus$ group, which includes Epstein-Barr and Kaposi's sarcoma herpesviruses. These herpesviruses replicate lytically in lymphocytes, epithelial and fibroblastic cells, and persist in lymphoblastoid cells. MDV has a complex life cycle and uses two means of replication, productive and non-productive, to exist and propagate. The method of reproduction changes according to a defined pattern depending on changes in virus-cell interactions at different stages of the disease, and in different tissues. Productive (lytic) interactions involve active invasion and take-over of the host cell, resulting in the production of infectious progeny virions. However, some herpesviruses, including MDV, can also establish a non-productive (abortive) infection in certain cell types, resulting in production of cell-associated progeny virus. Non-productive interactions represent persistent infection, in which the viral genome is present but gene expression is limited, there is no structural or regulatory gene translation, no replication, no release of progeny virions and no cell death. Reactivation of the virus is rare, and usually the infectious virus can be re-isolated only after cultivation in vitro. MDV establishes latency in lymphoid cells, some of which are subsequently transformed. In this review article, recent knowledges of the pathogenesis mechanisms followed by MDV infection to sensitive cells and chickens are discussed precisely.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.687-693
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• 2004

Composite membranes with a titania layer were prepared by soaking-rolling method with the titania sol of nanoparticles formed in the sol-gel process and investigated regarding the vapor permeation of various organic mixtures. The support modification was conducted by pressing $SiO_2$ xerogel of 500 nm in particle size under 10 MPa on the surface of a porous stainless steel (SUS) substrate and designed the multi-layered structure by coating the intermediate layer of ${\gamma}-Al_2O_3$. Microstructure of titania membrane was affected by heat-treatment and synthesis conditions of precursor sol, and titania formed at calcination temperature of 300$^{\circ}C$ with sol of [$H^+$]/[TIP]=0.3 possessed surface area of 210 $m^2$/g, average pore size of 1.25 nm. The titania composite membrane showed high $H_2/N_2$ selectivity and water/ethanol selectivity as 25-30 and 50-100, respectively. As a result of vapor permeation for water-alcohol and alcohol-alcohol mixture, titania composite membrane showed water-permselective and molecular-sieve permeation behavior. However, water/methanol selectivity of the membrane was very low because of chemical affinity of permeants for the membrane by similar physicochemical properties of water and methanol.