In this study, ultrasonic spray pyrolysis combined with salt-assisted decomposition, a process that adds sodium nitrate (NaNO3) into a titanium precursor solution, is used to synthesize nanosized titanium dioxide (TiO2) particles. The added NaNO3 prevents the agglomeration of the primary nanoparticles in the pyrolysis process. The nanoparticles are obtained after a washing process, removing NaNO3 and NaF from the secondary particles, which consist of the salts and TiO2 nanoparticles. The effects of pyrolysis temperature on the size, crystallographic characteristics, and bandgap energy of the synthesized nanoparticles are systematically investigated. The synthesized TiO2 nanoparticles have a size of approximately 2–10 nm a bandgap energy of 3.1–3.25 eV, depending on the synthetic temperature. These differences in properties affect the photocatalytic activities of the synthesized TiO2 nanoparticles.

A heterogeneous photocatalytic system is attracting much interest for water and air purification because of its reusability and economical advantage. Electrospun nanofibers are also receiving immense attention for efficient photocatalysts due to their ultra-high specific surface areas and aspect ratios. In this study, ZnO nanofibers with average diameters of 71, 151 and 168 nm are successfully synthesized by facile electrospinning and a subsequent calcination process at 500 ℃ for 3 h. Their crystal structures, morphology features and optical properties are systematically characterized by X-ray diffraction, scanning electron microscopy, UV-Vis and photoluminescence spectroscopies. The photocatalytic activities of the ZnO nanofibers are evaluated by the photodegradation of a rhodamine B aqueous solution. The results reveal that the diameter of the nanofiber, controlled by changing the polymer content in the precursor solution, plays an important role in the photocatalytic activities of the synthesized ZnO nanofibers.

Current synthesis processes for titanium dioxide (TiO2) nanoparticles require expensive precursors or templates as well as complex steps and long reaction times. In addition, these processes produce highly agglomerated nanoparticles. In this study, we demonstrate a simple and continuous approach to synthesize TiO2 nanoparticles by a salt-assisted ultrasonic spray pyrolysis method. We also investigate the effect of salt content in a precursor solution on the morphology and size of synthesized products. The synthesized TiO2 nanoparticles are systematically characterized by X-ray diffraction, transmission electron micrograph, and UV-Vis spectroscopy. These nanoparticles appear to have a single anatase phase and a uniform particle-size distribution with an average particle size of approximately 10 nm. By extrapolating the plots of the transformed Kubelka-Munk function versus the absorbed light energy, we determine that the energy band gap of the synthesized TiO2 nanoparticles is 3.25 eV

Despite numerous advances in the preparation and use of GaN, and many leading-edge applications in lighting technologies, the preparation of high-quality GaN powder remains a challenge. Ammonolytic preparations of polycrystalline GaN have been studied using various precursors, but all were time-consuming and required high temperatures. In this study, an efficient and low-temperature method to synthesize high-purity hexagonal GaN powder is developed using sub-micron Ga2O3 powder as a starting material. The sub-micron Ga2O3 powder was prepared by an ultrasonic spray pyrolysis process. The GaN powder is synthesized from the sub-micron Ga2O3 powder through a nitridation treatment in an NH3 flow at 800℃. The characteristics of the synthesized powder are systematically examined by X-ray diffraction, scanning and transmission electron microscopy, and UV-vis spectrophotometer.

This study is conducted to compare the problems affecting dietary habits and health status between a long-term exercise group and non-exercise group of males older than 50 years. Most subjects of the two groups consider regular exercise to be the most important factor for maintaining health, and recognize hypertension as the number one concern. The most common nutritional supplement among subjects is multiple vitamins, and sleeping time range from 6~8 hours. Breakfast fasting rate was 15.9% among non-exercise group (NEG), where overeating and eating out rates were higher among exercise group (EG) when comparing to NEG. Fasting rates of breakfast, and consumption rates of milk and dairy products, vegetables such as kimchi, and fruits and fruit juices are higher among the EG. Overeating and eating out rates are lower among NEG, whereas eating rates of proteins like meat, fish, eggs, beans, fried foods, high-fat meats carbonated drinks, ice cream, and salt intakes are higher. Rates of health, dietary habits, and nutrient intakes are higher among EG. Energy intakes among the two groups were below the standard level, Vitamin B2 intake is low in EG, and folic acid and calcium intakes were higher in NEG. The exercising group care more about health, eating habits and nutrient intakes, and low smoking rates are being observed. Thus, specific dietary improvement programs for adult men, are required, and it is necessary to consider the practice of nutrition education.

목적: 본 연구는 리더선수의 행동을 탐색하여 선수 리더십의 구성요인을 결정하고, 리더선수의 역할과 영향력 그 리고 행동에 따른 팀의 기여도와 선수들의 선호도를 파악하는데 목적이 있다. 방법: 연구대상은 서울 지역 11개 종목의 대학교 운동선수 110명을 대상으로 연구를 진행하였고, 개방형 설문지를 활용하여 리더선수 행동 탐색에 따른 선수 리더십의 구성요인을 귀납적 내용분석을 통해 결정하였으며, 빈도분석과 기술통계를 활용하여 리더선 수의 역할, 영향력, 팀의 기여도와 선수들의 선호도를 파악하였다. 결과: 훈련과 시합상황에서 리더선수의 주요 긍정⋅부정 행동은 파이팅을 외치며 격려하는 행동과 팀원에게 화를 내는 행동이며, 일상생활에선 생활규칙을 엄 수하는 행동과 생활규칙 준수를 강압적으로 지시하는 행동으로 나타났다. 둘째, 선수 리더십의 구성요인은 솔선수 범, 격려와 분위기 형성, 지도와 조언 제공, 단합과 의사소통, 부정적 영향력의 5요인으로 결정하였다. 셋째, 선수 들이 인식하고 선호하는 리더선수는 주장으로 나타났으며, 리더선수의 영향력에 대해 10개 팀은 긍정적으로, 나 머지 2개 팀은 부정적으로 나타났다. 넷째, 가장 높은 팀의 기여도와 선수들의 선호도는 훈련상황에서 팀원의 부 족한 부분에 대한 피드백을 제공해주는 행동, 시합상황에서 박수를 치거나 엄지를 치켜세우는 행동으로 나타났으 며, 일상생활에선 팀원을 나서서 도와주는 행동과 생활규칙을 엄수하는 행동이 가장 높은 팀의 기여도와 선수들 의 선호도를 보였다. 결론: 선수 리더십을 발휘하는 리더선수의 상황별 주요 행동과 선수 리더십의 구성요인을 도출하였으며, 이러한 리더선수의 역할과 영향력 그리고 행동에 따른 팀의 기여도와 선수들의 선호도를 파악하였다.