• Elastomers and Composites
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• v.47 no.2
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• pp.141-147
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• 2012

Silicone resin has no water-absorbing function because it is a strong hydrophobic polymer. However, addition of super absorbent polymer gives much better absorbency than that of conventional silicone resin. In this study, we developed novel silicone materials with water-absorbing function by choosing three types of amorphous acrylic super absorbent polymers with different particle sizes, determining the mixing ratio of the three polymers and applying the mixtures into two-component type silicone material for medical purpose. The change in the mechanical properties such as tensile strength, tear strength, compressive strength and hardness was investigated by varying the particle size and content ratio of the added super absorbent polymers while preparing the silicone resins. The absorbency of the silicone resins was measured over time. Additionally, the particle shape of the super absorbent polymers as well as the distribution within the silicone resin was observed using an optical microscope.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.1
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• pp.5-14
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• 2003

Principles of a novel pulse growing method are described. The method realized in the crystal growing on a seed from melts under raw melt feeding provided a more reliable control of the crystallization process when producing large alkali halide crystals. The slow natural convection of the melt in the crucible at a constant melt level is intensified by rotating the crucible, while the crystal rotation favors a more symmetrical distribution of thermal stresses over the crystal cross-section. Optimum rotation parameters for the crucible and crystal have been determined. The spatial position oi the solid/liquid phase interface relatively to the melt surface, heaters and the crucible elements are considered. Basing on that consideration, a novel criterion is stated, that is, the immersion extent of the crystallization front (CF) convex toward the melt. When the crystal grows at a <> CF immersion, the raised CF may tear off from the melt partially or completely due to its weight. This results in avoid formation in the crystal. Experimental data on the radial crystal growth speed are discussed. This speed defines the formation of a gas phase layer at the crystal surface. The layer thickness il a function of time a temperature at specific values of pressure in the furnace and the free melt surface dimensions in the gap between the crystal and crucible wall. Analytical expressions have been derived for the impurity component mass transfer at the steady-state growth stage describing two independent processes, the impurity mass transfer along the <> path and its transit along the <> one. The heater (and thus the melt) temperature variation is inherent in any control system. It has been shown that when random temperature changes occur causing its lowering at a rate exceeding $0.5^{\circ}C/min$, a kind of the CF decoration by foreign impurities or by gas bubbles takes place. Short-term temperature changes at one heater or both result in local (i.e., at the front) redistribution of the preset axial growth speed.

• The Journal of Korean Medicine
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• v.23 no.1
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• pp.100-111
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• 2002

Objectives : In order to obtain the clinical type of facial palsy sequelae and try to make the treatment protocols for each, I observed patients who visited Gunpo-Wonkwang oriental medicine center with Bell’s palsy sequelae that were treated over three months. Methods : I make the value standard of muscle paralysis, contraction, synkinesis and acquired the results as follows. Results and Conclusions : 1. The distribution of age and sex was as follows : females of 41-50 years were the most common demographic, females of 51-60 years and males of 31-40 years were the second, males of 51-60 years were the third, females of 21-30 years and males of over 60 years were the fourth, and males of 41-50 years were the fifth. 2. The distributions of period of disease were as follows : 3-6 months was the most, 12-18 months was the second, 6-12 months and over 24 months was the third, and 18-24 months was the fourth. 3. The sequelae distributions of disease were as follows. In the group of 3-6 months, 12 persons (80%) showed palsy and atrophy, 10 persons (66.6%) showed synkinetics. In the group of over 6 months, all patients showed muscle palsy, muscle atrophy and synkinetics. All groups showed lower sensitivity of muscles, but the group of 18-24 months and the group of over 24 months showed more. Tinnitus was shown by the groups of 12-18 months and 3-6 months. Facial muscle pain was shown by the group of3-6 months only, Crocodile's tear was shown by the groups of 18-24 months and over 24 months. 4. The total palsy rates of sequela patients and palsy rates by muscle for disease period were as follows. The total palsy rate was 27.94%; the palsy rates for the group of 6-12 months and the group of over 24 months was lower than the total palsy rate. The rates of the groups of 3-6, 12-18, 18-24 months were higher than the total palsy rate. The palsy rate of zygomatic minor, levator labii superior muscle was higher than the total palsy rate for all groups. 5. Synkinetics manifestation rates by disease period were as follows. Total synkinetics manifestation rate was 73.81 %; the manifestation rate of the group of 6-12 months was lower than total synkinetics manifestation rate. For the groups of 12-18, 18-24, and over 24 months it was more than the total synkinetics manifestation rate. The group of over 24 months, total synkinetics induced by orbicularis oculi muscle and orbicularis oris muscle. 6. Facial muscle atrophy rates by disease period were as follows. Total atrophy rate was 5.26%; in the groups of 6-12, 18-24, over 24 months, the atrophy rates were higher than the total atrophy rate. The groups of 3-6 and 12-18 months showed lower than the total atrophy rates, while the atrophy of the levator palpebrae superioris muscle and levator palpebrae inferioris muscle was higher than in other groups.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.153-162
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• 2014

Purpose: This study was assessed to investigate the change of subjective and/or objective symptoms and the light transmittance of lens caused by the use longer than recommended wearing time of daily disposable circle contact lenses (circle lens) in dry eyes. Methods: Three daily disposable circle lenses made of etafilcon A, hilafilcon B, and nelfilcon A were applied on 30 dry eyes with smaller tear volume than normal eyes in their twenties free from any eye diseases by when subjects complained any kind of discomfort. On the first and the last days of lens wearing, subjective discomfort, blinking rate, lens centration on corneal surface and visible light transmittance of lens were recorded at every case and compared. Results: The circle lens wearers complained subjective discomfort and quit the lens wearing when they wore the circle lens longer than 10 hours even though there were some difference according to the lens materials of daily disposable circle lens. However, around 20% of dry eyes could wear the circle lens made of non-ionic materials longer than 40 hours. Dry eyes showed most sensitive feeling of subjective discomfort against the circle lens made of etafilcon A among three different lens materials. On the last day of lens wearing, the representative subjective discomforts were irritation, stiffness, dryness and tiredness. When the subjects wore circle lens more than the recommended time, blinking rate was significantly increased about 20~30% regardless of lens materials when it compared with the values right after lens wearing. On the last day of lens wearing, the vertical direction of lens centration was shifted to pupil center however, its distribution in horizontal direction was wide compared with the distribution right after lens wearing. Especially, the centration of etafilcon A lens was unstable. Furthermore, the visible light transmittance of 3 different circle lenses in dry eyes has significantly been reduced around 15% averaged. Conclusions: From these results, it was known that the increase of dryness and stiffness caused by overusage of daily disposable circle lens induced excess irritation and decreased visible light transmittance and caused significant more blinking, which provoked lens decentration. It was also revealed that dry eyes showed sensitive reaction subjectively and objectively against the overusage of circle lens made of high water content/ionic lens material even there were some difference of the degree depending on the individual and the lens material. Thus, this research can be suggested as the basic reference for the education about some unexpected problems and the side effect caused by the wearing of circle lens in dry eyes.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.91-98
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• 2000

To investigate the distribution of dry eye and to accept diagnosis methods of dry eye in ophthalmic shop, this study was performed on 81 persons(male : 49, female : 32). 1. We divided two group for diagnosing dry eye by dry eye screening questionnaire : one was dry eye symptom group(49.3%) and the other was non-dry eye symptom group(50.7%). 2. Non-invasive break-up time(NIBUT) which was measured by using Tear $scope^{(R)}$ (Killer. co)was longer than invasive break-up time(IBUT). 3. A blink rate in dry eye symptom group(10%) was measured lesser than 10 cycle/min, in non-dry eye symptom group(14.9%). 4. In shirmer test there were lesser than 10mm/5min in dry eye symptom group(67.5%), in non-dry eye symptom group(39%). 5. Cornea and conjunctival staining by rose bengal represented Mild 25%, medium 36.25%, extreme 38.75% in dry eye symptom group. Non-dry eye symptom group was showed Mild 19.51%, medium 14.63%, extreme 12.19%. 6. These results showed that the patient showed dry eye symptom in 3 items of eye examination was 22.5%, 4 items 25%, 5 items 30%, 6 items 15%.