• Journal of the Korean Chemical Society
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• v.60 no.4
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• pp.261-266
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• 2016

The major physical characteristics of macromolecules used in silicone hydrogel ophthalmic lenses include optical transmittance, oxygen permeability, water content, and refractive index. For the preparation of highly functional silicone hydrogel lens materials, two silicone monomers were used in the presence of 2-hydroxyethyl methacrylate (HEMA) and hydroxypropyl methacrylate (HPMA). The samples containing HEMA and HPMA had oxygen transmissibility (Dk) values in the range of 73.38–50.98 × 10^-11 (cm²/s) (mLO₂/mL×mmHg) and 71.94–42.80 × 10^-11 (cm²/s) (mLO₂/mL×mmHg), respectively. Furthermore, the water contents of samples containing HEMA and HPMA were in the range of 32.73–34.67% and 31.94–33.74%, respectively, and the refractive indices were in the range of 1.4348–1.4364 and 1.4385–1.4407, respectively. Thus, silicone monomers containing HEMA and HPMA are expected to be useful for fabricating high-oxygen-permeability silicon hydrogel ophthalmic lenses.

• Journal of the Korean Chemical Society
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• v.63 no.1
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• pp.12-23
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• 2019

The new experimental data of liquid-liquid equilibrium (LLE) of aqueous two-phase system (ATPS) consisting of poly(ethylene glycol) 3000 + tri-potassium citrate at different pH were presented. It was found that an increase in pH resulted in the expansion of the two-phase region. The TLL and STL increased with increasing the pH values. The Merchuk equation can be appropriately employed to correlate the binodal curves and also the tie-line compositions were adjusted to both the Othmer-Tobias and Bancroft equations. In order to calculate the compositions of the phase and the ends of the tie-lines, density and refractive indices as two physical properties were used. Finally, the extended UNIQUAC, UNIFAC, Virial-(Mobalegholeslam & Bakhshi) and modified UNIQUAC-FV were used to measure the phase equilibria at different pH. The results of the models suggested that it can be used quite well to correlate the LLE in an aqueous solution of polymer-salt.

• Journal of the Korean Geotechnical Society
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• v.25 no.6
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• pp.89-99
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• 2009

In order to clarify the relation between the physical properties and the strength parameters of compaction materials and to develop a method for evaluating the strength parameters required for design from the physical indices including void ratio and dry density, compaction test, one-dimensional compression test, and exhausted-drained triaxial compression test were carried out with decomposed granite soils. The test results showed that the specimens became over-consolidated by compaction and the increase of the strength parameters of the specimens by the increase of the compaction energy could be verified quantitatively. A method for the evaluation of strength parameters from the void ratio of soil after compaction using preconsolidation theory which evaluates over-consolidation of materials was developed and its engineering applicability was tested for verification.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.3
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• pp.13-20
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• 2024

PURPOSE: To determine the effect of four weeks of exercise training on knee circumference and range of motion (ROM), pain perception, wellness, and VO_2max in patients at Osun State University Teaching Hospital, Osogbo, Nigeria. METHODS: Forty subjects who met the inclusion criteria were randomized into control and experimental groups. patients were subjected to four weeks of flexibility and strengthening exercise, which included squatting exercise, ROM exercise, both groups were given some cardiovascular exercise. VO_2max), Wellness score and circumference. RESULTS: Compared to the baseline values (week 1), there was increase in the knee ROM, and decrease in the pain perception in both groups after four weeks. However, the improvements seen in the experimental group, were significantly better relative to the control group after four weeks of intervention. owever, knee ROM and wellness scores of the experimental group, and the VO_2max of both significantly increase, but significantly decrease in the knee circumference and pain perception of both groups following 4 weeks of exercise was recorded. CONCLUSION: he exercise modality in the study promote cardiovascular endurance, knee joint integrity, reduce pain perception in subjects. xercise intervention s beneficia to both groups since both reduction in the pain felt and also in knee swelling.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.529-534
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• 2005

This study performed an physical analysis on the characteristics of urban environmental sound divided into three parts depending on their features. Object sounds were classified into traffic sound, waster sound and spatial sound. Traffice sound was selected because it is dominant sound in urban environment, and water sound is selected because it generally supplies pleasantness in contrast to traffic sound, Finally spatial sound was considered because it represents sound in various places of city having lots of behaviors and types of sound due to them. Physcal analysis was carried out using sound quality indices based on Zwicker's loudness, $L_{Aeq}$(equivalent noise level), Ln(percentile noise level) and other acoutical attributes applied to previous study. Through the analysis, this study aims to compare the acoustical characteristics of urban environmental sound and to provide fundamental data for the evaluation of urban environmental sound.

• Journal of Korean Society of Rural Planning
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• v.17 no.3
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• pp.1-13
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• 2011

This study aims to analyse the landscape ecological characteristics of 39 rural villages in Korea and classify them according to their characteristics. After producing a land-use map of rural villages, this study quantified the landscape ecological characteristics of the subject sites as 18 landscape indexes using Fragstats. By applying the landscape index as a variable, selecting 4 factor through principal component analysis and conducting a cluster analysis, it classified them into 3 groups. Rural villages of Korea have their unique types of land-use due to the influence of physical environment such as geography, climate and ecology as well as the social and cultural influence, and the characteristics of land-use can be analysed and classified using the landscape index, the quantified landscape ecological characteristics.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2434-2441
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• 2015

This paper proposes an exercise recommendation system for treating obesity that provides systematic recommendations for exercise and diet. Five body indices are considered as indicators for recommend exercise and diet. The system also informs users of prohibited foods using health data including blood pressure, blood sugar, and total cholesterol. To maximize the utility of the system, it displays recommendations for both indoor and outdoor activities. The system is equipped with multimode sensors, including a three-axis accelerometer, a laser, a pressure sensor, and a wrist-mounted sensor. To demonstrate the effectiveness of the system, field tests are carried out with three participants over 20 days, which show that the proposed system is effective in treating obesity.

• Journal of The Korean Astronomical Society
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• v.24 no.1
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• pp.107-116
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• 1991

With a modern microdensitometer and POSS glass copies, we have performed an automated star counting in two colors, blue and red, over the region containing Bok globule B361. Distribution of the measured extinction values over the projected angular distance from the cloud center was approximated by a power-law, and the resulting power-law indices for the blue and red are shown to be distinctly different from each other. The difference in the power-law index indicates that the mean dust size increases towards the cloud center. Possible physical causes for such size variation are briefly discussed.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.101-105
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• 2006

The computational fluid dynamic analysis has been conducted for the thermo-chemical flow field in an arcjet thruster with mono-propellant Hydrazine (N2H4) as a working fluid. The Reynolds Averaged Navier-Stokes (RANS) equations are modified to analyze compressible flows with the thermal radiation and electric field. The Maxwell equation, which is loosely coupled with the fluid dynamic equations through the Ohm heating and Lorentz forces, is adopted to analyze the electric field induced by the electric arc. The chemical reactions of Hydrazine were assumed to be infinitely fast due to the high temperature field inside the arcjet thruster. The chemical and the thermal radiation models for the nitrogen-hydrogen mixture and optically thick media respectively, were incorporated with the fluid dynamic equations. The results show that performance indices of the arcjet thruster with 1kW arc heating are improved by amount of 180% in thrust and 200% in specific impulse more than frozen flow. In addition to thermo-physical process inside the arcjet thruster is understood from the flow field results.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.209-212
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• 2001

High quality Taros thin films have been obtained from anodizing. The as-deposited amorphous films have excellent physical and electrical properties: refractive indices ~2.15, dielectric constants ~25, and leakage currents <10$^{-8}$ Ac $m^{-2}$ at 1MV $cm^{-1}$ , 700$\AA$ thickness. We fabricated a MIM element with theses T $a_2$ $O_{5}$ films which had perfect current-voltage symmetry characteristics using a new process technology which was post annealing of whole MIM element instead of conventional annealing conditions (top-electrode metals, annealing conditions) on the capacitor performances were extensively discussed throughout this work.k.