• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.1
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• pp.25-30
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• 2000

The conditions for callus formation and plant regeneration were confirmed in Italian ryegrass (Lolium mulfiorum Lam.). Among SH (Schenk and Hildebrandt), MS (Murashige and Skoog) and N6 medium (Chu) MS medium was highest degree of efficiencies respectively in callus formation and plant regeneration. In this study, we determined volume of hormones and other compounds appended in media. For callus formation, only $5\;mg/\;{\ell}$ of 2,4-D (2,4-dichlorophenoxy acetic acid) was appended in their media. For plant regeneration, we used MS medium containing $1.0\;mg/\;{\ell}$ of BA and $0.1\;mg/\;{\ell}$ of NAA.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1972.03a
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• pp.17.2-17
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• 1972

The group of tumors now generally termed Neurilemmoma or Schwanno ma was first described by Verocay, in 1908, and in 1910, he termed them "neurinoma". In 1935 Stout proposed the term neurilemmoma, believing that they arise from nerve sheath or Schwann's cells. Neurilemmoma is an encapsulated, solitary tumor arising in any nerves with Schwann's cell sheath. They may occur at any age and have no preponderance of sex and developing site, however, usually occur in the head and neck area in 25% of cases and have not shown metastasis and are radioresistant. Authors report 5 cases of neurilemmoma surgically surgically removed under the local and general anesthesia at ENT department of SNUH during the last 5 years, with review of the literatures.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.21 no.1
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• pp.104-112
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• 2008

Objective : This experimental study was preformed to investigate the effect of ethanol extract of Belamcandae Rhizoma (EBR) on dermal bioactive properties related to cosmeceuticals such as radical scavenging activity and depigmentation. Methods : The free radical scavenging activity of EBR was assayed in cell free systems using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Antibacterial potency was measured by the size of inhibition zone with change of volume. Cell viability was measured by MTT assay and tyrosinase activity was assessed using L-DOPA. Results : EBR showed slightly radical scavenging activity and protected against UVB-induced cell cytotoxicity. Futhermore, EBR showed antibacterial activities on S. epidermidis and S. aureus. Although the proliferation of B16/F10 cells was decreased by EBR, necrosis was not revealed. EBR augmented tyrosinase activity and dendrite outgrowth in B16/F10 cells. Conclusions : These results suggest that EBR has antioxidative ＆ antibacterial activities, and stimulate melanogenesis.

• Journal of Powder Materials
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• v.2 no.1
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• pp.44-52
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• 1995

Effects of the extrusion temperature and die angle on the tensile properties of SiCIyAl composites in powder extrusion have been investigated. SiCP/Al composites were extruded at various extrusion temperatures (450, 500, $550^{\circ}C$) under the extrusion ratio of 25 : 1. The ram speed was maintained at 13 cm/min for all the extrusion conditions. The surface of the extruded rod appeared to be smooth without tearing at 450 and 50$0^{\circ}C$, whereas it was very rough due to tearing at $550^{\circ}C$. It was found that the tensile strength and elongation of the composites extruded at $500^{\circ}C$ are greater than those of composites extruded at $450^{\circ}C$ This is due to the easier plastic deformation of composite extruded at $500^{\circ}C$, compared with the composites extruded at $450^{\circ}C$. The effect of die angle was examined under 20=60, 120, $180^{\circ}$die angles at extrusion temperature of $500^{\circ}C$ under 25:1 extrusion ratio. The tensile strength of the composites extruded with 20=$60^{\circ}$approved to be higher than that of the composties extruded with 28 : 120 and $180^{\circ}$This is attributable to the higher extrusion pressure, which mixed composite powders could be densely consolidated at elevated temperatures, resulting from high friction force between billet and sliding surface of conical die.

• Journal of Korean Academy of Nursing Administration
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• v.21 no.5
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• pp.552-560
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• 2015

Purpose: This study was performed to identify the mediating effect of empowerment in the relationship between head nurses' servant leadership and organizational commitment among clinical nurses. Methods: A cross-sectional survey design was used. A convenience sample of 249 nurses was recruited from three hospitals located in J province, South Korea. Data were collected by self-report questionnaires, including general characteristics, servant leadership, empowerment, and organizational commitment. Data were analyzed with descriptive statistics, Pearson correlation coefficients, independent t-test, One-way ANOVA, and linear regression using the SPSS 22.0 program. Results: Head nurses' servant leadership perceived by clinical nurses significantly influenced their organization commitment. Empowerment partly mediated the effect of servant leadership on organizational commitment. Conclusion: The findings suggest the importance of improving nurse managers' servant leadership and empowering nurses to increase their organizational commitment.

• Journal of computational fluids engineering
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• v.16 no.3
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• pp.75-81
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• 2011

The turbo blowers having large power capacity are generally composed of the variable inlet guide vane, the impeller and the variable diffuser. In the present study, the effect of the stagger angles on the aerodynamic performances has been investigated by CFD methods. The design specifications of the reference model having 400kW power were given as 7.43kg/s of mass flow rate, 1.66 of pressure ratio with 12000rpm of impeller rotating speed. As the first simulation parameter, the diffuser vane angle was varied in the range of ${\pm}$20 degree from the initial-design point. The inlet guide vane angles, as the second one, was changed in the range of ${\pm}$40 degree from the initial-design point. The commercial Navier-Stokes solver, ANSYS-CFX, was applied to solve the three-dimensional unsteady flow fields inside the turbo blower. Through the numerical results, the desirable setting angles were proposed to fit the best performance to the variation of the operating conditions.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2357-2362
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• 2008

LHP is different from a conventional heat pipes in design and heat and fluid flow passages. The situations of the former is much complex than the latter. In LHPs, evaporation occurs at the contact interface between the heating plate and the porous wick, so some micro channels machined at the contact interface serve to let the vapor flow out of the evaporator. This complexity of contact geometry was known to cause a high resistance to heat flow. The present work was to study the problem of heat passage across the contact surface for LHPs and determine those values contact resistance. For two cases of contact structures, the thermal contact resistances were examined experimentally, one being obtained through mechanical contact under pressure and the other through sintered bonding. Nickel powder wick and copper plate were used for specimens. The result showed that a substantial reduction of contact resistance of an order of degree could be obtainable by sintered bonding.

• Journal of the Korean Magnetics Society
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• v.8 no.3
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• pp.161-168
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• 1998

In this paper, a algorithm is proposed, which is applicable to the transient analysis of diffusion equations by combined use of the Laplace transform and the finite element method. The proposed method removes the time terms using the Laplace transform and then solves the associated equation with the finite element method. The solution which is solved at frequency domain is transformed into time domain by use of the Laplace inversion. To verify the proposed algorithm, a heat conduction problem is analysed. And the solution showed a good agreement with analytic solution. Because the time-step method is not needed, the proposed method is very useful in solving various kinds of diffusion equations.

• The Korean Journal of Applied Statistics
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• v.30 no.1
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• pp.181-193
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• 2017

The paper introduces bottom-up and optimal combination methods that can analyze and forecast hierarchical time series. These methods allow forecasts at lower levels to be summed consistently to upper levels without any ad-hoc adjustment. They can also potentially improve forecast performance in comparison to independent forecasts. We forecast regional traffic accident counts as time series data in order to identify efficiency gains from hierarchical forecasting. We observe that bottom-up or optimal combination methods are superior to independent methods in terms of forecast accuracy.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1710-1716
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• 2008

The Loop Heat Pipe (LHP) operates to pump the working fluid by means of the capillary force in a wick structure. Particularly, it is difficult to design and manufacture the evaporator consisted of a grooved container and a compensation chamber as well as the wick structure. This study is related to design and manufacture the grooved container coupled with wick structure, the properties of the wick structure such as the permeability, the porosity, and the maximum capillary pressure were measured to apply the cooling technology for Insulated Gate Bipolar Transistor (IGBT). The container of the LHP was manufactured by the electrical discharge process and the wick structure was sintered with the nickel particle by an axial-press apparatus with the pulse electronic discharge. As results, the properties of the wick were experimentally obtained about 60% of the porosity, 35kPa of the maximum capillary force and $1.53{\times}10-13m2$ of the permeability.