• Economic and Environmental Geology
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• v.54 no.1
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• pp.117-126
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• 2021

Satellite magnetic observations reflect the magnetic properties of deep crust about the depth of Curie isotherm that is a boundary where the magnetic nature of the rocks is disappeared, showing long wavelength anomalies that are not easily detected in near-surface data from airborne and shipborne surveys. For this reason, they are important not only in the analyses on such as plate reconstruction of tectonic boundaries and deep crustal structures, but in the studies of geothermal distribution in Antarctic and Greenland crust, related to global warming issue. It is a conventional method to compute the spherical harmonic coefficients from global coverage of satellite magnetic observations but it should be noted that inclusion of erroneous data from the equator and the poles where magnetic observations are highly disturbed might mislead the global model of the coefficients. Otherwise, the reduced anomaly model can be obtained with less corruption by choosing the area of interest with proper data processing to the area. In this study, I produced a satellite crustal magnetic anomaly map over East Asia (20° ~ 55°N, 108° ~ 150°E) centered on Korean Peninsula, from CHAMP satellite magnetic measurements about mean altitude of 280 km during the last year of the mission, and compared with the one from global crustal magnetic model (MF7). Also, a comparison was made with long wavelength anomalies from EMAG2 model compiled from all near-surface data over the globe.

• Journal of Preventive Medicine and Public Health
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• v.44 no.1
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• pp.56-64
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• 2011

Objectives: The purpose of this study was to estimate the prevalence and correlated factors of high myopia in 19 year-old men in Southeast Korea. Methods: This retrospective study was based on the medical checkup data of conscription during 2005. The study subjects were 19 years old men in Busan, Ulsan and Gyeongsangnam-do. The health checkup data of the conscripts consisted of noncycloplegic autorefraction test, the biometric data and social factors. To analyze the social and biometric effects, we classified the biometric factors into 4 or 5 groups and the social factors into 3 groups. High myopia was defined as a spherical equivalent of under -6.0 diopter. Data analysis was performed using the chi square test for trends and multiple logistic regression analysis. The SAS(version 9.1) program was used for all the analyses. Results: The prevalence of high myopia was 12.39% (6256 / 50 508). The factors correlated with high myopia were the residence area (OR, 2.07; 95% CI, 1.77 to 2.4 for small city; OR, 2.01; 95% CI, 1.72 to 2.34 for metropolis; the reference group was rural area), academic achievement (OR, 1.43; 95% CI, 1.34 to 1.53 for students of 4-and 6-year-course university; the reference group was high school graduates & under) and blood pressure (OR, 1.54; 95% CI, 1.10 to 2.16 for hypertension; OR, 1.09; 95% CI, 1.02 to 1.17 for prehypertension; OR, 1.10; 95% CI, 1.01 to 1.20 for hypotension; the reference group was normal blood pressure). Conclusions: More than one tenth of the young men were high myopia as one of the risk factor for visual loss. Further studies on high myopia and its complications are needed to improve eye health in Southeast Korea.

• The Journal of the Convergence on Culture Technology
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• v.1 no.2
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• pp.65-69
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• 2015

Teeth and bones are very resistance to high temperatures and remain recognizable even after prolonged exposures to heat. The effects of heating and burning on teeth have been studied with the aim of discerning a characteristic signature withstanding high temperature, but there have been few studies about a human cremated ash, especially Korea. We are recognizable by elemental composition and can be detected in human cremated ash samples by Scanning electromicroscopy/Energy dispersive X-ray spectrometry analysis(SEM/EDS), cremated, at $800{\sim}900^{\circ}C$ for 1 hour. In this temperature range, different crystals morphologies(spherical, irregular and hexagonal) are observed in SEM. Calcium(Ca) and oxygen(O) increases steadily after cremation in EDS. We suggest that cremated bone have been provided with calcium oxide(CaO) formation at temperature above $900^{\circ}C$. This study offers basic data to assess the structure and elemental compositions of human ash and to determine if these remain identifiable after exposure to extreme temperatures.

• Transactions on Electrical and Electronic Materials
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• v.13 no.5
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• pp.252-255
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• 2012

In order to characterize insulation properties of epoxy/micro-silica/nano-silicate composite (EMNC), long-term and short-term AC treeing tests were carried out undr non-uniform electric field generated between needle-plate electrodes. In a long-term test, a 10 kV (60 Hz) electrical field was applied to the specimen positioned between the electrodes with a distance of 2.7 mm in an insulating oil bath at $30^{\circ}C$, and a typical branch type electrical tree was observed in the neat epoxy resin and breakdown took place at 1,042 min after applying the 10 kVelectrical field. Meanwhile, the spherical tree with the tree length of $237{\mu}m$ was seen in EMNC-65-0.3 at 52,380 min (36.4 day) and then the test was stopped because the tree propagation rate was too low. In the short-term test, an electrial field was applied to a 3.5 mm-thick specimen at an increasing voltage rate of 0.5 kV/s until breakdown in insulating oil bath at $30^{\circ}C$ and $130^{\circ}C$, and the data was estimated by Weibull statistical analysis. The electrical insulation breakdown strength for neat epoxy resin was 1,763 kV/mm at $30^{\circ}C$, while that for EMNC-65-0.3 was 2,604 kV/mm, which was a modified value of 47%. As was expected, the breakdown strength decreased at higher test temperatures.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.1 no.1
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• pp.92-99
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• 1991

The reaction obtaining $SiO_2$ fine particle from $ Si(OC_2H_5)_4$consists of two steps, that is, hydrolysis and polycondensation. Polycondensation is the first order with respect to the concentration of $Si(OC_2H_5)_4$As the concentration of water, ammonia reaction temperature are increased, the reaction rate constant of polycondensation is increased.Silica particles formed are spherical and very uniformly dispersed. The diameters of them are be-tween 0.06 and $0.27\mu\textrm{m}$. As the initial concentration of $Si(OC_2H_5)_4$is decreased and the reaction temper-ature is increased, the diameters of silica particles are reduced. The rate of particles growth derived from time vs, conversion data, is represented as follows; d=a.ln(Xa)+b, where d is the diameter of silica and a, b are constant. The final diameter of silica approaches to the value of b.

• Journal of the Korea Fashion and Costume Design Association
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• v.17 no.1
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• pp.141-154
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• 2015

The purpose of this study is to look for a development plan for strategic brand logo by a means of scrutinizing general characteristics and trend in the visual properties of outdoor logo brands. In this study, data research and analysis were conducted over the 68 outdoor brands in circulation in the domestic market based on the information on the website of each brand in order to examine the visual characteristics of an outdoor brand logo. For this, it was performed to examine the desired brand concept of each brand and to analyze the visual characteristics of typeface, color, and type of logo. The results of this research are the followings: First, it was found that the most popular typeface in outdoor brand logos is a capitalized Gothic type. It seems that the logo type is designed to symbolize power, toughness, and masculinity and to express the concept of sportswear brand. Second, when it comes to color, black color tone appeared most frequently, and also reddish colors among chromatic colors were prevailing over others like green, blue, or yellow. It is believed that reddish colors were used to express passion, power, youthfulness, and energy; black color tone for tough, masculine power. Third, the logo symbol of outdoor brands mostly contains mountain, the heads of powerful animals, spherical shape/abstract image that embodies outdoor sports activities. It was analyzed that these resulting symbols were chosen to convey the images of nature, conquest, challenge, future, and passion that are the brand concept of most outdoor brands. Today, in our country, the logo of an outdoor brand is the important factor that symbolizes the brand concept, function, or characteristics. Therefore, the necessity of constant follow-up researches is required to devise the way of designing the brand logo that can build brand power and enhance brand image.

• The Journal of Pediatrics of Korean Medicine
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• v.29 no.4
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• pp.12-22
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• 2015

Objectives Myopia has a higher prevalence rate in eastern countries, which also have a higher rate of educational fever compared to western countries. Considering this, social costs paid for myopia will increase rapidly in Korea. Although the development of myopia treatment is necessary, there has been a lack of relevant studies. Thus, this study aims to produce data to prevent unnecessary treatments and medical expenses. Methods The objective is to evaluate the effect of periocular acupressure exerted by a medical massager for myopia. This is an open-label, prospective, single-arm, and pre and post superiority study. The subjects are 7~12-year-old myopia patients with under 5 D (diopter) of spherical equivalent. A total of 56 subjects were enrolled. The selected subjects will wear the massager for 15 minutes twice a day for 24 weeks. The primary endpoint is the refraction change. The secondary endpoint is the axial length change. Statistical analysis was performed at a significant level of 0.05, using a two-tailed test. The criterion for significantly improved refraction was $-0.17{\pm}0.50$ D/6 months and that of axial length change was 0.126 mm. Results and Conclusions This study did not include a control group because children represent a vulnerable group. This objective study will bring some impact on Korean medical myopia treatment. A long-term confirmatory clinical study may be necessary in future.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.149-155
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• 2015

Purpose : Recently, many researchers and golf coachers demonstrated that X-factor and X-factor stretch had a co-relationship with driving distance. However, its relationship is still controversial and ambiguous. Thus, the aim of this study was to examine the relationship among X-factor, X-factor stretch and swing-related factors, including driving distance in elite golfers. Method : Seventeen male elite golfers (handicap: ${\leq}4$) with no history of musculo-skeletal injuries participated in the study. Thirty spherical retro-reflective markers were placed on including the middle point of PSIS, the right/left ASIS, the right/left lateral acromion of the scapula, driver head and shaft grip. All motion capture data was collected at 100Hz using 6 infrared cameras. Carry distance, club speed, ball speed, smash factor, launch angle, and spin rate were collected from radar-based device, TrackMan. Results : Pearson's correlation coefficient method was used to find the correlations among X-factor, X-factor stretch and swing-related factors. Positive correlations between driving distance and other swing-related factors which include club speed(r=.798, p<.001), and ball speed(r=.948, p<.001) were observed. In contrast to the swing-related factors, X-factor and X-factor stretch had no relationship to driving distance. Conclusion : These results indicate that X-factor and X-factor stretch are not key regulators in driving distance.

• Journal of the Korean earth science society
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• v.25 no.7
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• pp.604-614
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• 2004

Using three-components geomagnetic data from a permanent geomagnetic observatory in Icheon, we have computed the power spectrum of each geomagnetic component, amplitude, phase and estimation error of transfer function for each day in the 6 months period July 2002${\sim}$December 2002. The temporal variation of power spectrum have random appearances with repeating relative strong and weak magnitude, which is considered as solar activities. However, there is no clear long-term trend. In the case of amplitude, phase and error of transfer function, even though there are some random patterns over the periods of 1000 s and under 100 s, they seem to be comparatively stable without manifest temporal changes. Futhermore, we have estimated electrical field by assuming P$_{1}\;^{0}$ spherical harmonics and then calculated the approximated apparent resistivity for each day. As a result, the variations of resistivity depend on the temporal magnitude of spectral power in horizontal magnetic fields rather than hydrological changes in near surface.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.319-324
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• 1984

Spatial variability of sand, silt, and clay contents on Hwadong SiCL and Jungdong SL was studied by using geostatistical concept. The measurements were made within a $33{\times}14m^2$ area at the nodes of 2 by 2m grids. The validity of all assumptions (stationarity, variogram models, etc.) was proved by Jack-knifing procedure and frequency distribution performed on the original data grids. The variogram of sand content on Hwadong SiCL was different from the linear model and that of clay content of Jungdong SL the linear and the spherical model in calculation of both kriged values and kriged variances in identification of its choice for simplicity.