Cha J.-R.,Dankook UniversityChungnam |
Lee C.W.,Dankook University |
Lee J.Y.,Sungkyunkwan University |
Gong M.-S.,Dankook UniversityChungnam
Dyes and Pigments | Year: 2016
Blue thermally activated delayed fluorescent (TADF) emitters were developed by linking a donor moiety to a triazine core via the ortho-position of an aromatic moiety. Three phenylcarbazole derivatives with different substituents were incorporated into the 4,6-diphenyltriazine core to prepare the blue TADF emitters. The photophysical properties and device performance of the blue TADF emitters were investigated, and the blue TADF emitters with 3,6-dimethyl-9-phenylcarbazole as the donor moiety showed a high quantum efficiency of 14.7%. © 2016 Elsevier Ltd
Dockko S.,Dankook UniversityChungnam |
Khishigjargal S.,Dankook UniversityChungnam |
Kang I.-M.,Dankook UniversityChungnam |
Oh H.-J.,Dankook UniversityChungnam |
And 2 more authors.
Sustainable Environment Research | Year: 2010
Reverse osmosis (RO) membranes have been widely used for desalination as well as water and wastewater treatment facilities. Cleaning process is important to maintain stable operation as well as prevention of membrane fouling. Purpose of this research is to analyze electrostatistic and chemical characteristics after cleaning of RO membrane. Synthetic water for experiment consists of SiO2, one of major foulants in desalination process. Four RO membranes of polyamide are used and examined about effect of chemical cleaning. Ethylene diamine tetraacetic acid, sodium dodecil sulface and sodium hydroxide pellets are applied for cleaning process after operation in synthetic water. Then, cleaning was performed with chemicals at concentration 0.1-1%. Transmittances of Fourier transform infrared of four membranes are compared at each cleaning concentration to demonstrate difference of chemical composition between new membrane and cleaning membrane. Type B of RO membrane is the most vulnerable to cleaning among four membranes. In terms of zeta potential, new membrane has -16 to +6 mV while scaled membrane has -18 to 2 mV. However, it changed from -23 to 0.9 mV after cleaning. The flux changes are compared with membrane before/after fouling and after cleaning. In comparison with the salt rejection of RO new and cleaned membranes, the rejection of the cleaned membranes only goes down 0.7%. Though, cleaning changes the characteristics of membrane surface and flux, it does not greatly affect salt rejection. © 2010, Chinese Institute of Environmental Engineering. All rights reserved.
Kim K.,Dankook UniversityChungnam |
Shin S.C.,Dankook University |
Shim J.E.,Daejeon University
Nutrition Research and Practice | Year: 2015
BACKGROUNDS/OBJECTIVES: The effects of malnutrition on growth of toddlers and preschoolers by socioeconomic status are not well known. This study aimed to examine the effects of dietary intake on growth outcomes in toddlers and preschoolers by household income level. SUBJECTS/METHODS: The study population was a total of 1,687 children aged 1 to 5 years that participated in the KNHANES from 2009 to 2011. Growth of children was assessed by height for age (HFA) and weight for height (WFH). Children were classified into three groups according to children’s HFA and WFH compared to the 10th and 90th percentiles of the 2007 Korean Children and Adolescent Growth Standard. Average monthly household income was divided into quartile groups. Dietary intake data were obtained by using the one day 24-hr recall method. Risks of inadequate intake of nutrients and unfavorable growth were estimated by using a multiple logistic regression model adjusted for sex, age, region, and energy intake. RESULTS: The low HFA group (< 10th percentile) had significantly lower intakes of energy, carbohydrate, and thiamin as compared with the high group (≥ 90th percentile). For WFH status, vitamin C intake was lower in the low group than in the high group. Household income level was related to WFH status but not HFA. Children from lower income households were more likely to have high WFH than those from higher income households (P for trend = 0.038). Household income status was also significantly related with risk of inadequate intake of micronutrients such as thiamin (P for trend = 0.032) and vitamin C (P for trend = 0.002), showing higher odds of inadequate intakes in children from lower income households. CONCLUSIONS: Children from lower income households were prone to be overweight and to have inadequate intakes of micronutrients such as thiamin and vitamin C. To reduce nutritional and health disparities, collective action in the public sector is required from early life. © 2015 The Korean Nutrition Society and the Korean Society of Community Nutrition.
Kwon O.-J.,Sejong University |
Park J.-H.,Dankook UniversityChungnam
International Journal of Multimedia and Ubiquitous Engineering | Year: 2014
An efficient single-image super-resolution based on the discrete wavelet transform is proposed. The low-resolution image to be enhanced is assumed to be the low-frequency subband of the high-resolution image to be reconstructed. A support vector machine that synthesizes the high-frequency subband based on the inter-subband correlation of the directional edges is designed. Subband coefficients are classified into one of homogeneous region, edge region, and textured region. The support vector machine is adaptively trained for each region. Experimental results of sample images show that the proposed system offers improvements in terms of both measured distortion and subjective appearance. ⓒ 2014 SERSC