• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.123-130
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• 2010

Purpose: The study was conducted to compare the values of auto-refraction, manifest refraction and cycloplegic refraction in school-aged children. Methods: One hundred five myopic school children ranged from 6 to 14 years old (210 eyes, $10.28{\pm}1.59$ years old) were recruited and noncycloplegic auto-refraction (AR) and manifest refraction (MR) were conducted and then underwent cycloplegia and refractive status (CR) again with the auto-refractometer. Results: Refractive powers measured by AR, MR, and CR were highly correlated. However, spherical and cylindrical powers of the subjects measured by AR were measured higher negative power than in CR (p<0.001). From 210 eyes, the discrepancy rate in the spherical and cylindrical powers were 40 eyes (19%) and 19 eyes (9%) of the total subjects, respectively and the differences between noncycloplegic and cycloplegic refractions were higher with the spherical and cylindrical powers increasing. Conclusions: The use of the autorefractometer in children with negative spherical power without cycloplegia may overestimate the actual myopia that subjective refraction is the most important in prescription for the eyeglasses and regression equations would be used to prognose the cycloplegic refraction from the auto-refraction as the basic data for the subjective refraction.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.644-647
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• 2006

The indium zinc oxide (IZO) thin films were deposited using a radio frequency reactive magnetron sputtering method. Among the various processing variables, $O_{2}$ concentration and annealing temperature after deposition were selected and the optical, electrical, and structural properties of IZO thin films were investigated. As the $O_{2}$ concentration increased, the deposition rate of IZO thin films decreased, the resistivity increased and the transmittance slightly increased. According to atomic force microscopy analysis, the IZO films deposited at pure Ar showed rough surface and those deposited with $O_{2}$ addition exhibited relatively smooth surface. The IZO thin films deposited at pure Ar were annealed at 250, 350, and $450^{\circ}C$, respectively. The IZO thin film deposited at pure Ar showed the lowest transmittance and resistivity and resistivity greatly increased at the annealing temperature exceeding $250^{\circ}C$. The higher annealing temperature IZO films were annealed at, the smoother surface the films showed. The x-ray diffraction revealed that IZO films annealed at higher temperature had better crystalline structures.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.141-141
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• 2013

We have generated the needle-typed nonthermal plasma jet by using an Ar gas flow at atmospheric pressure. Diagnostics of electron temperature anddensity is critical factors in optimization of the atmospheric plasma jet source in accordance with the gas flow rate. We have investigated the electron temperature and density of plasma jet by selecting the four metastable Ar emission lines based on the atmospheric collisional radiative model and radial profile characteristics of current density, respectively. The averaged electron temperature and electron density for this plasma jet are found to be ~1.6 eV and ~$3.2{\times}10^{12}cm^{-3}$, respectively, in this experiment. The densities of OH radical species inside the various bio-solutions are found to be higher by about 4~9 times than those on the surface when the argon bioplasma jet has been bombarded onto the bio-solution surface. The densities of the OH radicalspecies inside the DI water, DMEM, and PBS are measured to be about $4.3{\times}10^{16}cm^{-3}$, $2.2{\times}10^{16}cm^{-3}$, and $2.1{\times}10^{16}cm^{-3}$, respectively, at 2 mm downstream from the surface under optimized Ar gas flow 250 sccm.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.29 no.1
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• pp.1-13
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• 2024

The southwestern part of the East Sea is known to have a high primary productivity compared to those in the northern and eastern parts, which is attributed to nutrients supplies either by Tsushima Warm Current or by coastal upwelling. However, research on the biological pump in this area is limited. We developed machine learning models to estimate net community production (NCP), a measure of biological pump, with high spatial and time scales of 4 km and 8 days, respectively. The models were fed with the input parameters of sea surface temperature, chlorophyll-a, mixed layer depths, and photosynthetically active radiation and trained with observed NCP derived from high resolution measurements of surface O₂/Ar. The root mean square error between the predicted values by the best performing machine model and the observed NCP was 6 mmol O₂ m^-2 d^-1, corresponding to 15% of the average of observed NCP. The NCP in the central part of the Ulleung Basin was highest in March at 49 mmol O₂ m^-2 d^-1 and lowest in June and July at 18 mmol O₂ m^-2 d^-1. These seasonal variations were similar to the vertical nitrate flux based on the ³He gas exchange rate and to the particulate organic carbon flux estimated by the ²³⁴Th disequilibrium method. To expand this method, which produces NCP estimate for spring and summer, to autumn and winter, it is necessary to devise a way to correct bias in NCP by the entrainment of subsurface waters during the seasons.

• Journal of the Korean Society of Child Welfare
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• no.56
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• pp.253-281
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• 2016

The purpose of this study was to verify the clinical utility of th Korea Child Behavior Checklist 16-18(K-CBCL 6-18) in diagnosing ADHD among children with psychological disorders in child welfare institutions. The participants were 509 elementary school children(309 boys and 200 girls) who lived in child welfare institutions. They were assessed using the Korean ADHD Rating Scale(K-ARS) and K-CBCL 6-18. Only five scales of the K-CBCL 6-18 related with attention were used for analysis: syndrom total, externalizing total, aggressive behavior, attention problems and DSM-oriented ADHD scales. The results were as follows. First, K-ARS and K-CBCL 6-18 had significantly positive correlations with all five scales. Second, as a result of a t-test on the ADHD and the non-ADHD groups, which were divided using K-ARS, the mean scores of ADHD group were significantly higher than the non-ADHD group for all five scales of the K-CBCL 6-18. The hit rate of all five scales of the K-CBCL 6-18 was 60 to 70 percent. The syndrom total and externalizing total scales had high sensitivity, whereas the aggressive behavior, attention problems, and the DSM-oriented ADHD scales had high specificity. In addition, all scales had high positive predictive values. Third, as the result of a t-test on the ADHD group and the emotional disorder group, there were significant difference in the mean scores of the attention problems and the DSM-oriented ADHD scales. The attention problems and the DSM-oriented ADHD scales had a similar percentage of hit rate, high specificity and low sensitivity. Especially, the DSM-oriented ADHD scale revealed higher specificity than the attention problems scale. The results of this study suggested that the five scales related to attention of the K-CBCL 6-18 are useful in diagnosing ADHD in child welfare institutions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.4
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• pp.110-115
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• 2010

Transparent conducting gallium-doped zinc oxide (GZO) thin films which were deposited on Corning glass substrate using an Gun-type rf magnetron sputtering deposition technology. The GZO thin films were fabricated with an GZO ceramic target (Zn : 97[wt%], $Ga_2O_3$ : 3[wt%]). The GZO thin films were deposited by varying the growth conditions such as the substrate temperature, oxygen pressure. Among the GZO thin films fabricated in this study, the one formed at conditions of the substrate temperature of 200[$^{\circ}C$], Ar flow rate of 50[sccm], $O_2$ flow rate of 5[sccm], rf power of 80[W] and working pressure of 5[mtorr] showed the best properties of an electrical resistivity of $2.536{\times}10^{-4}[{\Omega}{\cdot}cm]$, a carrier concentration of $7.746{\times}10^{20}[cm^{-3}]$, and a carrier mobility of 31.77[$cm^2/V{\cdot}S$], which indicates that it could be used as a transparent electrode for thin film transistor and flat panel display applications.

• Korean Journal of Materials Research
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• v.10 no.6
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• pp.385-391
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• 2000

A kinetic study on the preparation of iron powder by hydrogen reduction of ferrous chloride vapor has been carried out both experimentally and theoretically. For the preparation of iron powder, ferrous chloride was vaporized and transported to a reaction zone by Ar gas used as carrier. Ferrous chloride vapor and hydrogen were mixed and subject to a reduction reaction at high temperature to produce iron powder and HCI gas. Iron powder was collected with organic solvent at the end of reaction zone and HCI gas was also absorbed in a caustic soda solution to determine the conversion ratio of ferrous chloride. For the development of rate equations, a 1st-order reaction and equilibration of ferrous chloride vapor with Ar gas were assumed. According to the results, the rate constant, k could be expressed as $k=7,879exp(-53,840/RT)\textrm{dm}^3/mole.sec$ and the activation energy was found to be 53.84kJ/mole. From TEM observation, the particle size distribution of iron powder produced was found to be in the range of $0.1~1.0{\mu\textrm{m}}$ which was not significantly influenced by reaction temperature or gas flow rates.

• Journal of Adhesion and Interface
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• v.6 no.3
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• pp.1-9
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• 2005

This study investigated the influence of atmospheric plasma factors such as RF power, treatment time, the gap distance between discharge and sample, and the gas flow rate of Ar on the surface property by using the design of experiment (DOE) method. The plasma treatment time (s), plasma power (W), gap distance (mm) between discharge and sample, and flow rate of Ar gas were in order of important factors for changing the surface free energy of PMMA plates. As a result, the most effective factor for improving the surface free energy of PMMA plates is the distance (mm) from discharge glow to sample plate. Because of the interaction between plasma power (W) and treatment time (s), the power dose (J) factor which multiply plasma power (W) by treatment time (s) should be significantly considered. The optimum condition for maximizing the surface free energy of PMMA plate was found at 1500J of power dose. Through XPS and AFM analysis, we also observed the change of chemical composition, surface morphology and roughness before and after plasma treatment. It is considered that the change of surface free energy of PMMA plate with plasma treatment is influenced by the introduction of polar functional group as well as the increase of surface roughness.

• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.9-14
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• 2011

A set of test was conducted on a SA-372 steel for CNG storage tank to study the effect of hydrogen embrittlement. Tensile tests were carried out several conditions such as CNG, HCNG and H2 gas environment including air and Ar under the 35 MPa. Also, the test speed was set at 4*10^-4/s and 4*10^-5/s respectively. To maintain the high pressure for environmental gas during test process, we chose MTS which was installed autoclave. Test results showed that tensile stress, elongation rate and cross sectional contraction under Ar and CNG charging condition were similar to that of reference of air. And there was little bit change with test speed variations. However, hydrogen added conditions such as HCNG and H2 were revealed noticeable change in elongation rate and cross sectional contraction. Tensile stress was still uniform for all conditions. From the results, the effect of hydrogen embrittlement was confirmed on the hydrogen enriched conditions. Also its effect was showed more strong with much hydrogen concentration and slower test speed.

• Journal of Internet Computing and Services
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• v.20 no.5
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• pp.113-119
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• 2019

The key features of 5G mobile communications recently commercialized can be represented by High Data Rate, Connection Density and Low Latency, of which the features most distinct from the existing 4G will be low Latency, which will be the foundation for various new service offerings. AR and self-driving technologies are being considered as services that utilize these features, and 5G Network Latency is also being discussed in related standards. However, it is true that the discussion of E2E Latency from a service perspective is much lacking. The final goal to achieve low Latency at 5G is to achieve 1ms of air interface based on RTD, which can be done through Ultra-reliable Low Latency Communications (URLLC) through Rel-16 in early 20 years, and further network parity through Mobile Edge Computing (MEC) is also being studied. In addition to 5G network-related factors, the overall 5G E2E Latency also includes link/equipment Latency on the path between the 5G network and the IDC server for service delivery, and the Processing Latency for service processing within the mobile app and server. Meanwhile, it is also necessary to study detailed service requirements by separating Latency for initial setup of service and Latency for continuous service. In this paper, the following three factors were reviewed for initial setup of service. First, the experiment and analysis presented the impact on Latency on the Latency in the case of 1 Data Lake Setup, 2 CRDX On/Off for efficient power, and finally 3H/O on Latency. Through this, we expect Low Latency to contribute to the service requirements and planning associated with Latency in the initial setup of the required services.