• 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.

• Journal of the Korean Ceramic Society
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• v.32 no.2
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• pp.239-247
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• 1995

Chalcogenide glasses with compositions of Ge10Se90-xTex(X=0~50 at.%) were prepared in order to investigate the effects of Te substitution on the transmission characteristics of Ge-Se glasses in the 8~12 ${\mu}{\textrm}{m}$ wavelength region. Absorption coefficients were observed to decrease with Te addition, indicating the improved transmission capabilities of Ge-Se-Te glasses as compared to binary Ge-Se glasses. XRD analysis of crystallized glasses suggested the formation of weaker Se-Te and/or Te-Te bonds with addition of Te substituting for Se in stronger Se-Se bonds. Incorporation of Te in excess of 20at% resulted in the formation of hexagonal Te phases when crystallized. It is speculated that the presence of Te-Te bonds with highly metallic bond character resulted in the enhanced crystallization tendencies of glasses. Fromation of Te-rich chains through gradual replacement of Se-Se with Se-Te and/or Te-Te bonds was further supported by decreases in glass transition and crystallization temperatures.

• Korean Journal of Materials Research
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• v.22 no.12
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• pp.669-674
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• 2012

Yellow phosphor dispersed color conversion glasses are promising phosphor materials for white LED applications because of their good thermal durability, chemical stability, and anti-ultraviolet property. Six color conversion glasses were prepared with high Tg and low Tg specimens of glass. Luminous efficacy, luminance, CIE (Commission Internationale de l'Eclairage) chromaticity, CCT (Correlated Color Temperature), and CRI (Color Rendering Index) of the color conversion glasses were analyzed according to the PL spectrum. Color conversion glasses with high Tg glass frit, sintered at higher temperature, showed better luminous properties than did color conversion glasses with low Tg glass frit. The characteristics of the color conversion glass depended on the glass composition rather than on the sintering temperature. The XRD peaks of the YAG phosphor disappeared in the color conversion glass with major components of $B_2O_3$-ZnO-$SiO_2$-CaO and, in the XRD results, new crystalline peaks of $BaSi_2O_5$ appeared in the color conversion glass with major components of $Bi_2O_3$-ZnO-$B_2O_3$-MgO. The characteristics of CIE chromaticity, CCT, and the CRI of low Tg color conversion glasses showed worse color properties than those of high Tg color conversion glasses. However, these color characteristics of low Tg glasses were improved by thickness variation. So color conversion glasses with good characteristics of both luminous and color properties were attained.

• 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.40 no.5
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• pp.423-427
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• 2003

Effect of the thermal poling on the 1.55 fm emission spectra in various Er$^{3+}$ -doped glasses was investigated with a special attention on the changes in the values of FWHM(Full Width at Half Maximum) intensity. Tellurite glasses poled at 28$0^{\circ}C$ with an electric voltage of 4 kV resulted in an approximately 6% increase in FWHM values compared with their unpoled counterparts. On the other hand, values for glasses, such as aluminosilicate, sulfide and chalcohalide, either decreased or remained unchanged. The characteristic results from tellurite glasses are most probably due to the presence of lone-pair electrons in the TeO$_4$ hi-pyramidal units that form the main network structure of tellurite glasses.

• Korean Journal of Health Education and Promotion
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• v.10 no.1
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• pp.87-97
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• 1993

The purpose of this study is to give practical information about eyesight care-preventing refractive error and actual conditions of wearing glasses(or contact lenses) to help school health education, For this study, 1,216 freshmen were sampled from liberal and vocational high schools in Seoul and the survey was successfully accomplished. Following are the major findings results of this study: 1. The percentage of the freshmen wearing glasses in girls high school were 57.5 percent in liberal high school and 41.7 percent in vocational high school. 2. The percentage of both the students and parents wearing glasses were 49.9 percent in liberal high school and 33.8 percent in vocational high school. 3. From the survey, the majority of the students began to wear glasses during their middle school years. The percentages were 46.6 percent in liberal high school and 62.1 percent in vocational high school. 4. The percentage of the students who got their glasses prescribed from an ophthalmic clinic were 60.6 percent in liberal high school, 31.5 percent in vocational high school and the rest got their glasses from the optician.. 5. The percentage of the students wearing glasses who didn't have optometry check-up for 6 months were 57.2 percent in liberal high school and 38.4 percent in vocational high school. The percentage of the students not wearing glasses in the same situation were 61.9 percent in liberal high school and 41.5 percent in vocational high school. 6. The percentage of the students who believe that the health education in school is necessary for the prevention of amblyopia were 79.2 percent of strdents attending in liberal high school, 82.9 percent in vocational high school, 81.5 percent of students wearing glasses and 80.8 percent of students not wearing glasses.

• Journal of the Korean Ceramic Society
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• v.30 no.4
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• pp.289-298
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• 1993

Properties in terms of the variation of the glass compositions, which were density (p), molar volume(Vm), atom/ion packing density (Dp), refractive index (nD), transformation temperature (Tg), dilatometric softening point (Td), thermal expansion coefficient (α), Young's modulus (E), and knoop hardness (KHN) were investigated in CaO-SiO2 glasses and CaO-P2O5-SiO2 glasses containing less than 10mole% of P2O5. Those properties were measured by density measurement kit, Abbe refractometer, dilatometer, ultrasonic pulse echo equipment, and micro hardness tester. When CaO content was increased in CaO-SiO2 glasses, p, Dp, nD, Tg, Td, α, E and KHN were increased, while Vm was decreased. When P2O5 was added to the CaO-SiO2 glasses with constant CaO/SiO2 ratio as 1.07, p, Dp, nD, Tg, Td, α, E and KHN were decreased, while Vm was increased. When the amount of P2O5 in glasses was kept constant, the changes of the properties with variation of CaO content in the CaO-P2O5-SiO2 glasses were very similar to those of CaO-SiO2 glasses. These phenomena could be explained by the structural role of P2O5 in the CaO-P2O5-SiO2 glasses, which was polymerization of siicate structures and resulted in [PO4] monomer structure in glasses. Due to this structural characteristics, the bond strength and packing density were changed with compositions. Proportional relationships between 1) np and Dp, 2) Tg, Td, α and CaO content, 3) E and Vm-1, and 4) KHN and P2O5 content were evaluated in this investigation.

• 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.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3841-3848
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• 2022

The effect of modifiers on the optical features and radiation defying ability of the Eu³⁺ ions doped multi constituent glasses was examined. XRD has established the amorphous nature of the specimen. The presence of various functional/fundamental groups in the present glasses was analyzed through FTIR spectra. The physical, structural and elastic traits of the glasses were explored. The variation in the structural compactness of the glass structure according to the incorporated modifier was enlightened to describe their suitability for a better shielding media. For the examined glasses, the metallization criterion value varied in the range 0.613-0.692, indicating the non-metallic character of the glasses with possible nonlinear optical applications. The computed elastic moduli expose the Li-containing glass (BTLi:Eu) to be tightly packed and rigid, which is a requirement for a better shielding channel. Furthermore, the optical bandgap and the Urbach energy values are calculated based on the optical absorption spectra. The evaluated bonding parameters revealed the nature of the fabricated glasses covalent. In addition, we investigated the radiation attenuation attributes of the prepared Eu³⁺ ions doped multi constituent glasses using Phy-X software. We determined the linear attenuation coefficient (LAC) and reported the influence of the five oxides Li₂O₃, CaO, BaO, SrO, and ZnO on the LAC values. The LAC varied between 0.433 and 0.549 cm^-1 at 0.284 MeV. The 39B₂O₃-25TeO₂-15Li₂O₃-10Na₂O-10K₂O-1Eu₂O₃ glass has a much smaller LAC than the other glasses.

• 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).