• Journal of the Korean Vacuum Society
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• v.21 no.2
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• pp.93-98
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• 2012

$Gd_{1-x}VO_4:{Eu_x}^{3+}$ phosphor powders were synthesized with changing the concentration of $Sm^{3+}$ ion by using a solid-state reaction method. The crystal structures of all the phosphors were found to be a tetragonal system, composed of (200) diffraction peak centered at $24.76^{\circ}$, and the morphology of grains approached the spherical form with homeogenous size distribution when the concentration of $Sm^{3+}$ ion was 0.05 mol. As for the photoluminescence properties, all of the phosphor powders, irrespective of $Sm^{3+}$ ion concentration, indicated the yellow, orange, and red emission peaked at 565, 603, and 645 nm respectively. As the concentration of $Sm^{3+}$ ion increases, the intensity of excitation spectrum showed a decreasing tendency on the increase of Sm3+ ion concentration. The maximum excitation and emission spectra were observed and the symmetry ratio was 1.19 at 0.05 mol of $Sm^{3+}$ ion.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.1
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• pp.54-64
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• 2021

Purpose: Nonalcoholic fatty liver disease (NAFLD) is the most frequent cause of chronic liver diseases in both adults and children with obesity. The aim of this study was to compare the changes in liver enzymes and metabolic profile in adolescents with fatty liver following selected school-based exercise (SBE) and high-intensity interval training (HIIT) interventions. Methods: In a semi-experimental study, 34 obese male adolescents with clinically defined NAFLD were divided into the HIIT (n=11, age=12.81±1.02 years, body mass index [BMI]=26.68±2.32 kg/㎡), selected SBE (n=11, age=13.39±0.95 years, BMI=26.47±1.74 kg/㎡), and control (n=12, age=13.14±1.49 years, BMI=26.45±2.21 kg/㎡) groups. The ultrasonography NAFLD grade, peak oxygen uptake (VO2peak), lipid profile, insulin resistance, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels of the participants were measured before and after the exercise interventions. Results: The BMI, waist-to-hip ratio, and body fat percentage of the participants decreased, and a significant increase in VO2peak was observed after the intervention; however, the HIIT group showed a significant improvement compared with the SBE group (p<0.01). Significant reductions were observed in the levels of insulin resistance, triglyceride, total cholesterol, ALT, and AST in both groups, although high-density lipoprotein levels decreased only in the HIIT group (p<0.01). Further, a significant reduction in low-density lipoprotein level was observed in the training groups (p<0.01), but this decrease was not significant compared with the control group (p>0.01). Conclusion: HIIT and SBE are equally effective in improving health parameters in obese children and adolescents.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.19-24
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• 2020

In this work, the electrical property of Si-doped β-Ga2O3 was investigated via a post-growth annealing process. The Ga2O3 samples were annealed under air (O-rich) or N2 (O-deficient) ambient at 800~1,200℃ for 30 mins. There was no correlation between the crystalline quality and the electrical conductivity of the films within the experimental conditions explored in this work. However, it was observed the air ambient led to severe degradation of the film's electrical conductivity while N2-annealed samples exhibited improvement in both the carrier concentration and Hall mobility measured at room temperature. Interestingly, the x-ray photoemission spectroscopy (XPS) revealed that both annealing conditions resulted in higher concentration of oxygen vacancy (VO). Although it was a slight increase for the air-annealed sample, high resistivity of the film strongly suggests that VO cannot be a shallow donor in β-Ga2O3. Therefore, the enhancement of the electrical conductivity of N2-annealed samples must be originated from something other than VO. One possibility is the activation of Si. The XPS analysis of N2-annealed samples showed increasing relative peak area of Si 2p associated with SiOx with increasing annealing temperature from 800 to 1,200℃. However, it was unclear whether or not this SiOx was responsible for the improvement as the electrical conductivity quickly degraded above 1,000℃ even under N2 ambient. Furthermore, XPS suggested the concentration of Si actually increased near the surface as opposed to the shift of the binding energy of Si from its initial chemical state to SiOx state. This study illustrates the electrical changes induced by a post-growth thermal annealing process can be utilized to probe the chemical and electrical states of vacancies and dopants for better understanding of the electrical property of Si-doped β-Ga2O3.

• Journal of muscle and joint health
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• v.26 no.2
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• pp.141-154
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• 2019

Purpose: This study aimed to analyze the effects of exercise on pulmonary function in patients with ankylosing spondylitis (AS). Methods: Randomized controlled trials (RCTs) were identified by searching MEDLINE, EMBASE, CENTRAL, and CINAHL (through Jan 2019). Three reviewers independently retrieved articles, extracted data, and assessed methodological quality using the Cochrane's Risk of Bias for randomized studies. Results: Fourteen studies met the inclusion criteria with a total of 729 participants. CE (SMD 0.58, 95% CI 0.41~0.75, p<.001) and $VO_2peak$ (SMD 0.56, 95% CI 0.24~0.88, p=.001) had a significant effect on the most exercise interventions. As a secondary variable, BASFI (SMD -0.53, 95% CI -0.70~-0.37, p<.001), BASMI (SMD -0.75, 95% CI -0.92~-0.58, p<.001) showed an effect size of more than medium. However, PFT and QoL did not produce a significant results. Conclusion: Pulmonary involvement is common in patients with AS and might have disturbed functionality and exercise modality. Exercise can be an effective intervention to improve pulmonary function in patients with AS. More attention is needed to improve the chest and spinal mobility to maintain the appropriate pulmonary function. It is also necessary to consider how to construct a patient-tailored exercise program to increase performance, accuracy and safety of exercise.