• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2366-2372
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• 2023

Are borate and silicate glasses suitable for working as shieling materials against fast neutrons? To correctly answer the above question, some silicate, and borate-based glasses were fabricated and irradiated with various doses of fast neutrons varied between 1.73 and 12.10 MGy. The color and hardness of the fabricated glasses were affected by the fast neutron fluence where the transparent glasses turned colored as well as the hardness of the fabricated glasses was decreased. The gamma-ray spectrometric analysis shows a high activity concentration produced in the barium borate glasses due to the formation of radioisotopes Ba-131 and Ba-133 reaches to 5.92E+05 Bq and 4.25E+03 Bq, respectively for sample Cd-5 Batch 3. Additionally, the gamma-ray spectrometric analysis for the sodium silicate glasses shows low activity concentrations emitted from isotopes formed due to the activation of Y₂O₃-associated impurities. These activities are low compared to that emitted by barium borate-based glasses.

• Journal of the Korean Ceramic Society
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• v.25 no.6
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• pp.665-670
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• 1988

The behavior of mechanical properties of ion exchanged glasses was investigated in this study. The used glasses were soda-lime-silica glasses that were produced by float process. The maximum values of the bending strength and the curvature depth are 45Kg/$\textrm{mm}^2$ and 8.6mm respectively treated at 45$0^{\circ}C$ for 6h, which are 4.4 times and 3.3 times higher than parent glass. In the case, the thermalshock resistance ΔT is 335$^{\circ}C$ that is 205$^{\circ}C$ higher than parent glass, which is the maximum values in this study. The maximum values of the surface microhardness is 490Kg/$\textrm{mm}^2$ in case of 43$0^{\circ}C$ for 4h. It is also found out that annealing points are increased linearly with increasing the amount of K+ ion exchange independent of treatment temperature. Furthermore, the present work shows that the ion exchange strengthened glasses are more effective than the physical tempering glasses ; the bending strength and the curvature depth are 1.8 times and twice higher respectively.

• Korean Journal of Health Education and Promotion
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• v.11 no.2
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• pp.87-106
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• 1994

Owing to the use of many cultural facilities, the elevation of life standards and the high level progress of industry, visual impairment was on increasing trends. Especially due to studying for many hours, the myopia of adolescents became a serious social issue. The purpose of this study was to understand adolescent's wearing glasses and eyesight condition, whether the primary myopia factor and the subjective symptoms were different between the myopia group and the normal group, between the wearing glasses group and the non-wearing glasses group, and the effect on physical, mental and study activity of myopia. The subject of investigation was 627 middle school students in Seoul and the investigation was accomplished from July 7th, 1993 to July 12th, 1993. The data were analyzed by the percentage, x²-test, t-test and ANOVA of SPSS. The results were as followed; 1. The rate of the right and left eyesights higher than 0.8 in the normal group was 47.0%, and those less than 0.7 in the myopia group was 53.0%. In the boy students, the normal group was 54.1%, the myopia group was 45.9%. In the girl students, the normal group was 39.2%, the myopia group was 60.8%. Therefore the girl students' myopia rates were higher than the boy students', and this result was significant(p<0.01). 2. The rate of wearing glasses of the middle school students was 44.6%. The rate of wearing glasses of the girl students was 56.8%. The rate of wearing glasses of the girl students was higher than that of the boy students 43.2%. The rate of necessary glasses of the middle school students was 6.1% and the rate of necessary glasses of the boy students was 7.9%, the rate of necessary glasses of the girl students was 4.1%. 3. In case of a family member of the student wear glasses, the rate of wearing glasses was higher. 4. In the myopia group, the main reason for not wearing glasses was "Uncomfortable"(63.3% in the boy students, 40% in the girl students). In case of the girl students, "Nonpermission of their parents" was 18.7% and remarkably higher than 5.1% in case of the boy students. 5. The factor of myopia was that "The bad attitude of watching TV closely" was 19.9%, that "The dimly-lit room" was 6.6%. 6. In order to protect eyesight, the rate of the students who practiced "Looking at something from afar 3∼4times a day" was 37.3%, the rate of the students who did "Eye exercise" was 17.5%, the rate of the students who took "A medicine for promoting nutrition" was 12.9%. The rate of taking the medicine was higher than 3.5% in the normal eyesight group. 7. After near working, the point of subjective symptoms was higher in the myopia group than in the normal group and in the wearing glasses group than in the unwearing group and in the girl students than in the boy students. 8. The longer time to watch TV, the higher point of subjective symptoms. The longer distance to watch TV, the lower point of subjective symptoms(p<0.05).

• Journal of the Korean Society of Safety
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• v.35 no.3
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• pp.105-115
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• 2020

This study compares the difference of fit factors (FF) and visual acuity according to masks and eyeglasses preferences for 54 participants. We the precautions and behaviors of discomfort when wearing masks of eyewear wearers. Contact lens discomfort and priority action of complaints was investigated Glasses fitting factors is Optical Center Height(OH), Vertex Distance(VD) and Pantoscopic Angle(PA). We measured those factors and expressed by the ratio of standard point and change point. Quantitative fit factor was measured by Portacount Pro+ 8038. Also, we selected to 6 exercises among 8 exercises OSHA QNFT (Quantitative Fit testing) protocol to measure the fit factors. The pass/ fail criterion of FF was set at 100. Visual acuity(VA) test chart is developed by Chunsuk Han was used, Descriptive statistics was performed. Descriptive statistics(SAS ver 9.2), it is used geometric means, Wilcoxon analysis(P=0.05) When wearing the mask preferentially, fit factor(FF) was high according to the step of glasses fitting parameter. on the other hand, when the glasses first choice, the visual acuity(VA) was high. there was no significant difference. In the case of fit factor (FF), mask first choice/ glasses first choice is OH (p=0.671/ p=0.332), VD (p=0.602/ p=0.571) and PA (p=0.549/ p=0.607). Visual acuity (VA), mask first choice/ glasses first choice is OH (p=0.753/ p=0.386), VD (p=0.815/ p=0.557) and PA (p=0.856/ p=0.562). The workers of workplace and office chose glasses but occupational health workers and students chose mask. In case of discomforts, it was suggested to remove the mask and tolerate discomforts. The main discomforts and usual action of lens were dryness, hyperemia, foreign body sensation, ophthalmodynia, decreased vision and glasses wearing. Therefore, it is necessary to develop a mask wearing method education program considering glasses fitting and develop a hybrid model that minimizes inconvenience when wearing glasses and a mask at the same time.

• Journal of the Korean Ceramic Society
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• v.30 no.6
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• pp.433-440
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• 1993

The bioactivity of glasses in the CaO-SiO2 system and CaO-P2O5-SiO2 system with less than 10mol% of P2O5 was investigated by in vitro test in simulated body flood(SBF). The formation of Ca.P film and hydroxyapatite on the surface of glasses after in vitro test was analysed by X-ray photoelectron spectoscopy (XPS), fourier transform infrared reflection spectroscopy (FT-IRRS), energy dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) observation. In the early stage of Ca.P film formation after in vitro test for CaO-SiO2 and CaO-P2O5-SiO2 glasses, the rate of Ca.P film formation on the surface of the glasses was dependent of structural parameter (Y) evaluated from the glass composition. First, in the case of the glasses having Y value below 2, Ca.P film and SiO2-rich layer were formed simultaneously, and there were no differences of the rate of Ca.P film formation in terms of the Y values. Second, in the case of the glasses having Y value above 2, the SiO2-rich layer was formed, and then Ca.P.Si mixed layer was formed in the silica gel structure of the SiO2-rich layer, and finally the Ca.P film on the surface of SiO2-rich layer. The rate of Ca.P film formation delayed as the Y values increased. The rate of hydroxyapatite formation of glasses (the rate of transformation from Ca.P film to hydroxyapatite) seems to be propotional to the rate of Ca.P film formation and Y value. The rate of hydroxyapatite formation of glasses belonging to the second group was delayed as structural parameter increased, and the hydroxyapatite crystal showed spherical growth in the early reaction stage, and then showed silkworm-like linear growth as the reaction time increased.

• Journal of the Korean Ceramic Society
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• v.34 no.8
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• pp.886-896
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• 1997

To investigate an effect of phase separation on precipitation characteristics of CuCl nanocrystals in CuCl doped nonlinear optical glasses, borosilicate glass systems with 9 different compositions with ~2wt% of CuCl were selected and CuCl doped glasses were prepared by melting and precipitation method. Microstructural properties of the CuCl doped glasses were analyzed by optical absorption spectroscopy, acid elution test, TEM, and EDXS. While phase separation did not occur in Glass A~D, interconnected and droplet microstructures due to phase separation were found in Glass E, F and Glass G~I, respectively. In the particular composition of the matrix glasses in this study, the precipitation of the CuCl particles was observed in the phase separable glasses, not in phase non-separable glasses. The CuCl particles were precipitated in both silica-rich phase region and boronrich phase region of the glass matrix. In the case of 7.7Na2O-36.6B2O3-52.7SiO2(mole%) glass, the larger CuCl particles than those in the silica-rich phase region were observed in the boron-rich phase region.

• Journal of the Korean Society of Costume
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• v.58 no.4
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• pp.35-46
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• 2008

The purpose of this study was to closely examine the history of glasses and their cases used in the middle and late of Joseon Dynasty and identify inherent quality of our traditional glasses cases through color analyses of glasses cases' material and shape. While theoretical examination was conducted based on the literatures of glasses and their cases that firstly appeared in around Japanese Invasion (Imjin war) of Korea in 1592, practical analyses were demonstrated on photos of glasses cases used in the middle and late of Joseon Dynasty collected from both museum pieces and the internet which were grouped into wood, fabric, paper, sharkskin, hawksbill and cow's horn in accordance with their materials. 623 color samples were abstracted from collected 159 glasses cases and quantity analyses on each material were performed respectively. Abstracted representative colors based on the result of color analyses were classified into the main materials and accessories' color scheme. The result of this study are as follow: firstly, both Yellow and Yellow Red were mostly used in main materials. In Fabric case's colors were widely used in embroidery and in animal matter material cases such as sharkskin, hawksbill and cow's horn, which can be used as itself or dyed, Green Yellow shown in high frequency. Secondly, accessories were analyzed into similarity coloration with main materials. From this finding, it turns out that our traditional cases have characteristic of similarity coloration between main materials and accessories. Red Purple and Purple Blue in high frequency in accessories used as an accent color. Finally, based on the analysis of hue and tone, while the middle and low value colors shown in very high frequency, the high-chroma colors hardly shown.

• Journal of the Korea society of information convergence
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• v.7 no.1
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• pp.47-53
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• 2014

This study was carried out recognition and status changes of optician for glasses fitting. It based on a survey results of twice in relation to the glasses fitting. The results are as follows. The ratio of glasses fitting about optician operation appeared to increase gradually. The positive awareness change appeared from the customer and optician about the cost charging about the glasses fitting. In the case of a plastic glasses, the burden for the inconvenience feeling and fitting frequency showed an increase with relation to the temple fitting. To reduce the burden of glasses fitting, The continuous education for the correct glasses usage need.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.96-98
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• 2004

At the previous papers, we showed that K2O-CaO-P2O5 glasses had a solubility in air so that they could be used for glass fertilizer. In this work, we fabricated the Eco-glass fertilizer containing trace elements such as B, Mg, Zn, Fe, Cu, Co, and Mo by a melt-quenching process and the dissolution properties of these glasses were investigated with pH meter and ICP analyzer. In case of the glasses containing the trace elements, effect of trace elements on the dissolutions is not obvious and ignorant the stability of mother glass. Also, the dissolution amounts of each trace elements depend on the mother glass composition and the quantity of each trace element, and mother glasses determined the dissolving velocity of chemical elements.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.105-109
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• 2003

This study surveyed the family relations of glasses wearer who were 80 primary student among 1321 students. They live in Iksan city, Jeon buk Province. The questionnaire of this study were the first wearing time, relations with parents, relations with brother and sister, and changing visual acuity. The question about when they were the first wearing glasses was answered 26% of all answerer at first grade, each 20% at second grade and third grade, 16.2% at preschool, 15% at fourth grade, and each 1.2% fifth and sixth grade. The Question was the relations between students' wearer and their parents about wearing glasses, 37.5% of wearer answered their parents didn't wearing glasses, 32.5% for mother was glasses wearer, 20% for mother and father were wearer, and 10% for father was wearer. In case of the relations between students' wearer and sister or brother about wearing glasses, 33.7% of wearer answered their brother or sister wearing glasses but the others only wearing glasses oneself. Visual acuity of the students' wearer was checked during wearing glasses. 58.7% of wearer answered their visual acuity didn't change, 35% for worse and 6.2% better visual acuity.