• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.4
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• pp.599-607
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• 2000

In this study, experiments have been performed to examine the effects of background gray-level on the depth-of-field and on the in-focus criteria. The normalized value of contrast(VC) and the gradient indicator(GI) were used as the in-focus criteria for the small and the large size-ranges of particles, respectively. The slightly larger number of pixels were detected with the brighter background. The maximum of the normalized value of contrast(VCmax) is decreased with the brighter background and its deviation from that with the background gray-level of 160 turned out to be about $pm$15% when the background gray-level changes from 100 to 200. However, the maximum gradient indicator(GImax) changes with the background gray-level within only $pm$5%. The depth-of-field for the VC-applicable particle-size range is largely dependent on the background gray-level. On the other hand, the depth-of-field for the GI-applicable particle-size range changes only slightly with the background gray-level. To keep the normalized standard deviation of the particle size within 0.1, the background gray-level should be set 160$pm$20 for both the VC-applicable and GI-applicable ranges which cover the particle size between $10{\mu}m$ and $300{\mu}m$.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2505-2511
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• 2014

Indium oxide nanocrystals ($In_2O_3$ NCs) with sizes of 5.5 nm-10 nm were synthesized by hot injection of the mixture precursors, indium acetate and oleic acid, into alcohol solution (1-octadecanol and 1-octadecence mixture). Field emission transmission electron microscopy (FE-TEM), High resolution X-Ray diffraction (X-ray), Nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FT-IR) were employed to investigate the size, surface molecular structure, and crystallinity of the synthesized $In_2O_3$ NCs. When covered by oleic acid as a capping group, the $In_2O_3$ NCs had a high crystallinity with a cubic structure, demonstrating a narrow size distribution. A high mobility of $2.51cm^2/V{\cdot}s$ and an on/off current ratio of about $1.0{\times}10^3$ were observed with an $In_2O_3$ NCs thin film transistor (TFT) device, where the channel layer of $In_2O_3$ NCs thin films were formed by a solution process of spin coating, cured at a relatively low temperature, $350^{\circ}C$. A size-dependent, non-monotonic trend on electron mobility was distinctly observed: the electron mobility increased from $0.43cm^2/V{\cdot}s$ for NCs with a 5.5 nm diameter to $2.51cm^2/V{\cdot}s$ for NCs with a diameter of 7.1 nm, and then decreased for NCs larger than 7.1 nm. This phenomenon is clearly explained by the combination of a smaller number of hops, a decrease in charging energy, and a decrease in electronic coupling with the increasing NC size, where the crossover diameter is estimated to be 7.1 nm. The decrease in electronic coupling proved to be the decisive factor giving rise to the decrease in the mobility associated with increasing size in the larger NCs above the crossover diameter.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.297-303
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• 2010

We report the particle-size distribution and comminution charactersitics of dolomite depending upon crushing equipment (hammer crusher and roll crusher) and crushing circuit (open and closed). The quantity of fine particles (< 100 mesh) produced by hammer crusher was 34 wt.% which is about three times that by roll crusher. The quantity of 14~25 mesh size fraction by roll crusher was 20 wt.% higher than that produced by hammer crusher. 80 wt.% of the crushing products by hammer crushing was under 35 mesh in size, while the particles produced by roll crushing were relatively coarse. The particle size of both the hammer and roll crushers decreased by employing closed crusing circuit in comparison to open circuit. Products of required particle-size were obtained effectively depending on appropriate crushing equipment and crushing circuit.

• Korean Journal of Materials Research
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• v.12 no.9
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• pp.701-705
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• 2002

High temperature tensile test has been performed at $450^{\circ}C$ at different strain rate with various grain size due to different reduction rate of Al-4wt%Mg-0.4wt%Sc alloy which is known to be one of useful superplastic alloys. The grain size of Al-4wt%Mg-0.4wt%Sc alloy is $67~100\mu\textrm{m}$ which is courser than that of the alloy which is commonly used as the superplastic material. The total elongation of the Al-4wt%Mg-0.4wt%Sc alloy is strongly dependent on the average grain size, and is a linear function of the inverse average grain size for the present alloy.

• The Journal of Industrial Distribution & Business
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• v.12 no.11
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• pp.17-31
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• 2021

Purpose: Despite the fact that face (i.e. Chemyon) is deeply-rooted in Korean culture and significantly affects the behavior of Korean people, the effect of face on leisure consumers' consumption behavior has only reported mixed findings, that is, significant and/or insignificant face effects have been reported. It is necessary to integrate prior research findings, and comprehensively examine the effect of face on leisure consumers' consumption behavior. The purpose of this study was to investigate the effect (i.e. effect size, and moderating variables) of face on leisure consumers' consumption behavior through meta-analysis. Research design, data and methodology: Among 1,019 face-related academic studies, retrieved from the academic research information services (RISS), 34 studies and 300 cases examining the effect of face on leisure consumers' consumption behavior were finally included for meta-analysis. Face measured as face sensitivity and/or a face sensitivity sub-component (shame-consciousness, formality-consciousness, and other-consciousness) were integrated in the meta-analysis. Leisure consumers' consumption behavior was classified as antecedents of purchase (overall conspicuous consumption tendency, overall symbolic consumption tendency, personality, high price, high quality, brand seeking, fashion seeking, enjoyment, other person (interpersonal) consideration, position, reference group, and attitude), purchase (purchase intention, unplanned purchase, purchase, and expenditure), and post-purchase (satisfaction, repurchase, and post-purchase). The data used in the meta-analysis was comprised of correlation coefficients, and the meta-analysis was performed using the R-program. Results: The overall mean effect size of face on leisure consumers' consumption behavior was .248. It was found that the effect size was the largest in the order of shame-consciousness face, formality-consciousness face, and other-consciousness face. Among the types of leisure consumers' consumption behavior categorized as dependent variables, the effect size was found to be largest in the order of position, attitude, reference group, post-purchase behavior, brand seeking, personality, trend seeking, etc. In addition, it was found that the leisure types moderated the effect size of face on leisure consumers' consumption behavior. The effect size was found to be largest in the order of skin diving, baseball, various leisure participation, dance, gambling, golf, etc. Conclusions: Face moderately or significantly influence leisure consumers' consumption behavior.

• The Journal of the Acoustical Society of Korea
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• v.25 no.4
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• pp.191-196
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• 2006

Human tend to rely their information about the size of a space on vision. However, it might be a common experience to perceive a certain difference in spaces without any visual difference, in such spaces as rooms for music performance, multimedia environments with multiple sound sources, and car cabins, where auditory experiences have a certain importance. In the present work, apparent auditory room size was measured at different positions in a room through a series of listening experiments. Also, measurement of room acoustic parameters was carried out and their relationships with perceived auditory room size were analyzed. The results suggest that apparent auditory room sizes were largely dependent on musical clarity, distance between a source and a receiver, and sound pressure level at the listening position. Also, the results from acoustic preference test suggest that smaller apparent room sizes were preferred for listening to orchestral, cello and flute music. The relationship between apparent auditory room size and vocal music was found to be statistically insignificant.

• Journal of the Korean Society of Radiology
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• v.18 no.4
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• pp.345-353
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• 2024

The purpose of this study was to suggest an appropriate collimation size and central X-ray incidence point by analyzing the correlation between the collimation size used in lumbar lateral examination and factors affecting the collimation size. the lumbar lateral examination results of 148 patients suitable for the purpose of this study were analyzed. The measurement method was to set the total horizontal width shown in the image to the size of the irradiation field(collimation) used during the examination. The distance connected vertically from the end of the dorsal field to the apophyseal joint of the third lumbar vertebra(AJD), the distance from the dorsal end of the image field to the center of the body of the third lumbar vertebra(BD), and the distance from the end of the dorsal field of the image to the center of the pedicle of the third lumbar vertebra(PD). The distance was measured. For comparative analysis of the mean values of dependent variables according to gender, age, height, weight, and body mass index, the mean values were compared using the independent samples t test and one-way ANOVA. For post hoc analysis, duncan was used. The correlation between independent and dependent variables was analyzed using Pearson correlation analysis. In this study, statistical significance was set at a p value of 0.05 or lower. The average value of the collimation size during the lumbar spine lateral examination was 252.45 mm, AJD was 102.11 mm, BD was 141.17 mm, and PD was 119.73 mm. The mean values of collimation size, AJD, BD, and PD were larger in men than in women, but statistical significance for the difference in mean values by gender was found only in BD (p<0.05). There was a slight difference in the mean value of each group according to age, but there was no statistical significance (p>0.05). The collimation size and mean values of AJD, BD, and PD according to height, weight, and body mass index differed depending on the independent variables, and the differences were all statistically significant (p<0.05). As a result of the correlation analysis, field size and AJD, BD, and PD showed no correlation with gender and age, a weak positive correlation with height, and a medium positive correlation with weight and body mass index. The results of this study showed that CS was correlated with height, weight, and BMI during lumbar lateral examination. If the entrance point of the central X-ray is moved to the appophyseal joint by considering weight and BMI when adjusting the collimation size in clinical practice, it is expected that the collimation size can be reduced bu about 5%.

• Journal of Radiation Protection and Research
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• v.9 no.1
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• pp.19-25
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• 1984

There is not yet an universal method of electron dosimetry. The Authors measured dose distributions of the electron beams from Clinac-18 by means of silicon detector connected to X-Y recorder, and compared them in water phantom with dose distributions measured by film and ion chamber, both inserted in polystyrene phantom. The results are as followings, 1. Dose in build-up region increased with the field size for all energy, and depth dose profiles of $6{\sim}12MeV$ beam under the depth of maximum dose were independent of field size, but those of 15 and 18 MeV beam were dependent on the field size. 2. The widths of penumbra by semiconductor detector were narrower than those by film for same energy beam. 3. Depth dose profiles by three different dosimeter did not coincide each other. In the build-up region, dose by semiconductor detector was lower than that by any other dosimeter.

• Journal of Hydrogen and New Energy
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• v.2 no.1
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• pp.57-67
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• 1990

This study is proposed to investigate the effect of electrode preparation method for Alkaline Fuel Cell using NaOH as an electrolyte on the Fuel Cell performance. The materials used for the preparation of electrode are Pt and Ag on Vulcan XC-72. Surface area of Vulcan XC-72 have different values according to the pretreatment conditions and the dispersion of Pt is dependent on the impregnation Particle size of Pt impregnated on unpretreated carbon was observed to be $20{\sim}40{\AA}$ and that on pretreated carbon in $N_2$ stream at $950^{\circ}C$ was found to be finely dispersed less then $15{\AA}$. The electrode performance was affected by the particle size of metals and operating temperature. It was revealed from this study that the optimum particle size about $30{\AA}$ and optimum temperature range is between $90{\sim}100^{\circ}C$.

• Journal of Environmental Impact Assessment
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• v.17 no.6
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• pp.321-333
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• 2008

Considering risks and artificial enrichments of metals in the soils of the study area, the study aims to analyze geology, grain size and geochemistry. Geology is mainly composed of gneisses and phyllites of metamorphic rocks, sandstones, siltstones, shales, tuffs of sedimentary ones and granites and andesites of igneous ones in the area. In the area, mean contents of metals are not meaningful in accordance with petrogenesis. The soil textures of the area are of S, lS and sL of sandy soil, L, scL, cL of loam and C, zC and sC of clayey soil. Mean contents of Ni, Cr, Co and Cu are meaningfully high in loam and clayey soil relative to sandy soil, whereas Ni, Zn, Cd contents are higher in clayey soil than in loam. Those differences imply the metallic contents are dependent to grain size. Based on the metal contents in the soils of the study area, Cu and Zn in loams and Pb in sandy soils are corresponded to soil contamination warning standards, and As showing 75mg/kg of maximum content in loams is assigned to soil contamination countermeasure standards, respectively. Artificial enrichment factor minimized wall rock and grain size relations is over 1 in Cr, Ni and Cu, but the factor is below 1 in average of other metals.