• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.186-192
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• 2022

Flow accelerated corrosion (FAC) is a type of pipe corrosion in which the pipe thickness decreases depending on the fluid flow conditions. In nuclear power plants, FAC mainly occurs in the carbon steel pipes of a secondary system. However, because the temperature of a secondary system pipe is over 150 ℃, in situ monitoring using a conventional ultrasonic non-destructive testing method is difficult. In our previous study, we developed a waveguide ultrasonic thickness measurement system. In this study, we applied a waveguide ultrasonic thickness measurement system to monitor the thinning of the pipe according to the change in pH. The Korea Atomic Energy Research Institute installed FAC-proof facilities, enabling the monitoring of internal fluid flow conditions, which were fixed for ~1000 h to analyze the effect of the pH. The measurement system operated without failure for ~3000 h and the pipe thickness was found to be reduced by ~10% at pH 9 compared to that at pH 7. The thickness of the pipe was measured using a microscope after the experiment, and the reliability of the system was confirmed with less than 1% error. This technology is expected to also be applicable to the thickness-reduction monitoring of other high-temperature materials.

• Journal of radiological science and technology
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• v.45 no.5
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• pp.413-422
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• 2022

In this study, 230 subjects of medical examination were investigated to figure out the relationship with common carotid artery intima-media thickness and cardiac diastolic function. In addition, the change in the carotid artery intima-media thickness according to the presence or absence of metabolic syndrome was examined. As a result of the study the carotid artery intima-media thickness was thick as the age increased and there was a large difference in those in their 60s and over. There was no gender difference. As for metabolic syndrome the carotid artery intima-media thickness was thicker in the study subjects with high blood pressure diabetes and dyslipidemia. The correlation between the carotid artery intima-media thickness and diastolic function indexes was significant. As a result of hierarchical regression analysis the thicker the intima-media thickness in the carotid artery the lower cardiac diastolic function.

• Progress in Superconductivity and Cryogenics
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• v.25 no.4
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• pp.24-27
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• 2023

Until now, many research activities have been conducted to commercialize high-temperature superconducting (HTS) wires for electric applications. Most of all researchers have focused on enhancing the piece length, critical current density, mechanical strength, and throughput of HTS wires. Recently, HTS magnet for generating high magnetic field shows degraded performance due to the deformation of HTS wire by high electro-magnetic force. The deformation can be derived from widthwise thickness non-uniformity of HTS wire mainly caused by wet processes such as electro-polishing of metal substrate and electro-plating of copper. Gradient sputtering process is designed to improve the thickness uniformity of HTS wire along the width direction. Copper stabilizing layer is deposited on HTS wire covered with specially designed mask. In order to evaluate the thickness uniformity of HTS wire after gradient sputtering process, the thickness distribution across the width is measured by using the optical microscope. The results show that the gradient deposition process is an effective method for improving the thickness uniformity of HTS wire.

• Journal of Korean Foot and Ankle Society
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• v.19 no.4
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• pp.188-192
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• 2015

Purpose: The purpose of this study is to provide Korean data on heel pad thickness according to age, gender, underlying disease, occupation, and body mass index (BMI). Materials and Methods: A retrospective study was conducted on 670 patients who underwent foot lateral plain radiography and magnetic resonance imaging (MRI) between January 2010 and July 2014. Through measurements of heel pad thickness, the usefulness and accuracy of foot lateral plain radiography was evaluated, and the mean Korean heel pad thickness in the weight-bearing and non-weight-bearing conditions was also evaluated according to age, gender, underlying disease, occupation, and BMI. Results: The 670 subjects with a mean age of 44 years (range, 12 to 84 years) consisted of 420 males and 250 females. The difference in heel pad thickness between non-weight-bearing foot lateral plain radiography and MRI was 0.69 mm. The heel pad thickness did not show a significant difference with age (p=0.08) and the presence of diabetes (p=0.09). With the increase in the Tegner score, the thickness of the heel pad increased (p=0.035), and subjects with a higher BMI had a thicker heel pad (p=0.03). The compressibility of the heel pad thickness showed no correlation with gender, diabetes, and Tegner score. Compressibility also increased with the increase in age and body weight. Conclusion: The mean Korean heel pad thickness measured through non-weight-bearing foot lateral plain radiography was 18.79 mm. The heel pad thickness increased with increasing BMI; however, age and diabetes did not show significant correlation. The compressibility of heel pad increased with the increase in age.

• Journal of Periodontal and Implant Science
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• v.41 no.2
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• pp.60-66
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• 2011

Purpose: The aim of this study is to evaluate the buccal and lingual bone thickness in the anterior teeth and the relationship between bone thickness and the tissue biotype. Methods: Three male and two female human cadaver heads (mean age, 55.4 years) were used in this study. First, the biotype of periodontium was evaluated and categorized into a thick or a thin group. Next, full thickness reflections of the mandible and the maxilla to expose the underlying bone for accurate measurements in the anterior regions were performed. After the removal of the half of the alveolar bone, the probe with a stopper was used to measure the thickness of bone plate at the alveolar crest (AC), 3 mm apical to the alveolar crest (AC-3), 6 mm apical to the alveolar crest (AC-6), and 9 mm apical to the alveolar crest (AC-9). The thickness of the buccal plates at the alveolar crest were $0.97{\pm}0.18\;mm$,$0.78{\pm}0.21\;mm$, and $0.95{\pm}0.35\;mm$ in the maxillary central incisors, lateral incisors, and canines, respectively. The thickness of the labial plates at the alveolar crest were $0.86{\pm}0.59\;mm$, $0.88{\pm}0.70\;mm$, and $1.17{\pm}0.70\;mm$ in the mandibular central incisors, lateral incisors and canines, respectively. Conclusions: The thickness of the labial plate in the maxillary anteriors is very thin that great caution is needed for placing an implant. The present study showed the bone thickness of maxillary and mandibular anteriors at different positions. Therefore, these data can be useful for the understanding of the bone thickness of the anteriors and a successful implant placement.

• The Korean Journal of Physiology
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• v.2 no.1
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• pp.89-93
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• 1968

Total body fat measurements were performed in 342 housewives. In 44 of them(age 38.4 yr.) both the densitometry and skinfold thickness methods were made and regression equations between skinfold and total body fat were derived. In the 298 housewives(age 35.0 yr.) skinfold thickness at four sites (arm, back, waist, abdomen) were measured and total body fat was calculated. The following results were obtained. 1. The data in 44 subjects by means of densitometry and skinfold thickness were: body weight: 51.8 kg, body length: 153.4 cm, body surface area: $1.47\;m^2$, body volume: 50.2 l, body density: 1.0334 kg/l, total body fat: 25.2% body weight, mean skinfold thickness at four sites 14.9 mm. 2. There were correlations of high degree between skinfold thickness and fat (%), fat (kg), and body density. The correlation coefficients were r=0.767, r=0.846, r= -0.765, respectively. Subsequently, the following regression equations were obtained. %fat=$0.39{\times}Mean$ skinfold thickness(mm)+19.36 Fat(kg)=$0.414{\times}Mean$ skinfold thickness(mm)+7.01 Body density=$-0.00099{\times}Mean$ skinfold thickness(mm)+1.0489 3. In 298 subjects mean skinfold thickness of four sites was 20.6mm and total body fat was calculated as 27.4% body weight from the above equation.

• The Korean Journal of Physiology
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• v.8 no.1
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• pp.31-37
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• 1974

Formulas for the prediction of total body fat from skinfold thickness in middle aged men were presented. Hydrostatic weighing was made on 35 middle-aged men $(age:\;40{\sim}50\;years)$ sad corrected for residual volume in lung. Skinfold thickness at four sites, namely, arm, back, waist and abdomen were compared with total fat calculated from the formula given by Keys and Brozek and regression equations were derived. In middle-aged men the observed values were: Body density, 1.07478 ; total body fat, 10.51% body weight; lean body mass, 89.49% body weight; arm skinfold thickness, 4.85mm; back, 10.4 ; waist, 7.72; abdomen, 7.62 and mean skinfold thickness of the four sites, 7.59 mm. The correlations between skinfold thickness and body density were high. The correlations between skinfold thickness and total body fat were also high. The coefficient of correlation between total body fat and arm skinfold, mean skinfold thickness were r=0.839 and r=0.862, respectively. Arm and mean skinfold thicknesses (x, mm) could be used as the representative value for the prediction of total body fat (y, % body weight). The regression equations were: On arm y=2.00x+0.99, With mean skinfold y=1.20x+1.41 The coefficient of correlation between body weight (kg) and mean skinfold thickness was r=0.733. The ratio of mean skinfold thickness (mm) to body weight (kg) in middle-aged men was 0.132.

• Korean Journal of Materials Research
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• v.21 no.1
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• pp.56-66
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• 2011

Multi-source evaporation is one of the methods to improve the thickness uniformity of thin films deposited by evaporation. In this study, a simulator for the relative thickness profile of a thin film deposited by a multi-source evaporation system was developed. Using this simulator, the relative thickness profiles of the evaporated thin films were simulated under various conditions, such as the number and arrangements of sources and source-to-substrate distance. The optimum conditions, in which the thickness uniformity is minimized, and the corresponding efficiency, were obtained. The substrate was a 5th generation substrate (dimensions of 1300 mm ${\times}$ 1100 mm). The number of sources and source-to-substrate distance were varied from 1 to 6 and 0 to the length of the major axis of the substrate (1300 mm), respectively. When the source plane, the area on which sources can be located, is limited to the substrate dimension, the minimum thickness uniformity, obtained when the number of sources is 6, was 3.3%; the corresponding efficiency was 16.6%. When the dimension of the source plane is enlarged two times, the thickness uniformity is remarkably improved while the efficiency is decreased. The minimum thickness uniformity, obtained when the number of sources is 6, was 0.5%; the corresponding efficiency was decreased to 9.1%. The expansion of the source plane brings about not only the improvement of the thickness uniformity, but also a decrement of the efficiency and an enlargement of equipment.

• Korean Journal of Optics and Photonics
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• v.15 no.4
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• pp.293-298
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• 2004

We investigate the effect of the wing width and thickness of a Double-Sided Deep-Ridge(DSDR) vertical directional coupler on the coupling length dependent on the polarization, We have found that the DSDR vertical directional coupler without a wing does not have polarization independent coupling lengths. The variation of the coupling length of TE and TM modes and the difference between the coupling lengths of the two modes are negligible as the wing width increases beyond the specific wing width for the same wing thickness. Thus, we can see that a DSDR vertical directional coupler has a wing width larger than the minimum wing width to obtain the polarization independent coupling length. The minimum wing width increases as the wing thickness increases for the same core thickness and as the core thickness decreases for the same wing width. Also, we have found that the minimum wing thickness is determined by the core thickness and the minimum wing thickness decreases as the core thickness increases.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.1
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• pp.67-76
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• 2020

Purpose : The purpose of this study was to provide more effective interventions for elderly men with weak core muscles by measuring the thickness of the muscles according to the five core stabilization exercise and comparing the thickness differences in muscles in each posture. Methods : The study selected 29 elderly men aged 65 to 80 years old among outpatient patients at S Medical Center in B city, and measured the muscle thickness by exercise posture once. In order to find out the thickness of the external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) muscles were measured by using rehabilitative ultrasound imaging (RUSI) in five exercise conditions. Results : A significant change in the thickness of the EO muscles in each group was measured by the method of motion, followed by the abdominal crunches (1.67±0.15), the lower body rotations (1.54±0.07). As a result of measuring the thickness of the IO muscles of each group according to the exercise method, the bridge group (1.14±0.22) was the highest, followed by the abdominal drawing group (1.05±0.03). As a result of measuring the thickness of the TrA muscles of each group according to the exercise method, the abdominal crunches (0.98±1.00) were the highest, and the bridge group (0.57±0.05) were higher in order of magnitude. Conclusion : Consequently, the five core stabilization exercises all affect changes in abdominal thickness and are expected to continue to require training studies on muscle posture.