• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.7
• /
• pp.457-463
• /
• 2013

The removal of sulfonamide antibiotics (SAs) by activated carbon was investigated by using granular activated carbon (GAC) tests and density functional theory (DFT) simulations. The GAC absorption tests show the removal efficiency of 68.4~90.7% and 99.0~99.9% in 1 and 24 hours, respectively. In both GAC tests, the removal efficiency of sulfamethazine (SMZ) was the highest followed by those of sulfathiazole (STZ) and sulfamethoxazole (SMTZ): SMZ > STZ > SMTZ. In DFT adsorption simulations, we found that the 4-aminobenzenesulfonamide parts of SMZ and STZ and the 3-methyl-1,2-oxazol-5-amine part of SMTZ are preferentially adsorbed on the edges of graphene model, provided that the adsorbates keep their structures without dissociation upon adsorption process. The adsorption energies of SMZ, STZ, and SMTZ are -4.91, -4.64, and -4.62 eV, respectively. This adsorption strength (SMZ > STZ > STMZ) agrees with the trend of the removal efficiency of SAs by GAC. In addition, dissociative adsorption configurations of SAs are discussed.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2015.11a
• /
• pp.42-42
• /
• 2015

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2019.05a
• /
• pp.391-392
• /
• 2019

• Journal of the korean academy of Pediatric Dentistry
• /
• v.29 no.3
• /
• pp.318-327
• /
• 2002

The purpose of this study was to make a comprehensive study and to provide information about the dental caries and plaque index of cerebral person, and to aid improvement of their oral health. The author examined intraorally 1180 deciduous teeth, 5626 permanent teeth of 264 (male:153 female:111) cerebral palsy person and 1526 deciduous teeth, 4140 permanent teeth of 220 (male:125 female:95) non cerebral palsy person as the control group. The results were as follows : 1. Cerebral palsy persons Had higher dft rate than non-cerebral palsy persons. 2. Dental caries incidence between males and females in cerebral palsy persons showed no difference, and dental caries incidence of types in cerebral palsy person showed no difference, either. 3. Mental, motor, speech handicap degrees were negatively related to DMFT rate and DMFT index, and institutionalized cerebral palsy persons and cerebral palsy persons of which parent's occupation is private business were found low DMFT rate and DMFT index. 4. Cerebral palsy persons were found to have higher plaque index than non-cerebral palsy persons, and non institutionalized cerebral palsy persons and self-supported cerebral palsy persons were found high plaque index. 5. Plaque index of male and female in cerebral palsy person showed no difference, and Plaque index of types in cerebral palsy person showed no difference, either Plaque index of handicap degrees(mental, motor, speech) showed no difference.

• Journal of Korean Public Health Nursing
• /
• v.16 no.1
• /
• pp.123-134
• /
• 2002

In order to investigate dental caries and oral health status of Kindergarten children, a study was conducted from 1st December, 2000 to 21st January 2001. The subjects were consisted of 117 toddler and pre-school children who were enrolled in 4 kindergartens in a county of Kangwondo. A structured questionnaire was used for dental health behavior and dental examination was given by dentist for detecting dental caries The result were as follows: 1. As for the oral health behavior, 71.8% of subjects brushed their tooth twice a day, 18.8% of them once a day, 8.5% of them 3 times a day and 0.9% of them do not brushed. 68.6% of children brushed their teeth in the morning and evening, 20.7% of them before go to bed, 7.4%, and 2.5% of them after meal and before brak first. 71.7% of children used combined with scrubbing and vertical method, 28.3% of them used scrubbing method. 61.5% of their mother answered they observed oral status of children regularly. 2. Prevalence rate of dental caries (dft) was 68.4%. The prevalence rate of dft were significantly higher in the old age children, mother's lower educational level. nourishing with breast feeding, using bottle, irregular eating of snacks 3. Mean dft was 2.95 ; decayed and filled teeth was 1.97 and 0.98, respectively. The mean dft were significantly higher in the old age children, mother's lower educational level

• The Journal of the Korean dental association
• /
• v.16 no.10 s.113
• /
• pp.791-794
• /
• 1978

The authors selected socio-geographically different sample areas. The dental caries on the deciduous teeth was observed and evaluated in each sample area. And then, dft rate, dft index, dt rate and ft rate were calculated and compared. The obtained results were as follows; 1. The dft rate of the deciduous teeth was 33.28% in the metropolitan area, 19.78% in city area, 18.21% in town area, 13.48% in field area, 15.26% in coastal area, 22.11% in mountain area, and 20.37% in hot spring area. 2. The dft index of the deciduous teeth was 4.51 in metropolitan area, 2.78 in city area, 2.59 in town area, 1.95 in field area, 2.30 in coastal area, 3.03 in mountain area, and 2.85 in hot spring area. 3. The dt rate of the deciduous teeth was 66.51% in metropolitan area, 95.38% in field area, 98.94% in hot spring area, and 100% in the other areas. 4. The ft rate of the deciduous teeth was 33.48% in metropolitan area, 4.61% in field area, 10.50% in hot spring area, and 0.00% in the other areas. 6. We could not find that the some dental cares for the dental caries on the deciduous teeth of Korean children were supplied in metropolitan area, and the track of dental cares was appreciated in the field area, but no trace was indentified in the coastal, mountain, city, and town areas.

• Journal of Electrical Engineering and Technology
• /
• v.6 no.4
• /
• pp.439-446
• /
• 2011

Frequency is an important operating parameter for the protection, control, and stability of a power system. Thus, it must be maintained very close to its nominal frequency. Due to the sudden change in generation and loads or faults in a power system, however, frequency deviates from its nominal value. An accurate monitoring of the power frequency is essential for optimum operation and prevention of wide area blackout. Most conventional frequency estimation schemes are based on the DFT filter. In these schemes, the gain error could cause defects when the frequency deviates from the nominal value. We present an advanced frequency estimation technique using gain compensation to enhance the DFT filter-based technique. The proposed technique can reduce the gain error caused when the frequency deviates from the nominal value. Simulation studies are performed using both the data from EMTP-RV software and the user-defined arbitrary signals to demonstrate the effectiveness of the proposed algorithm. Results show that the proposed algorithm achieves good performance under both steady state tests and dynamic conditions.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.4
• /
• pp.542-548
• /
• 2012

This study presents a new method of system modeling by using the Discrete Fourier Transform for the position control system of DC Motor. And the proposed method is similar to the method of System Identification by analysis of correlation of the measured input-output data. The measured output signals are transformed to the frequency domain using DFT. The Fourier Spectrum of the transformed signals is used for knowing to the feature of having an important effect on the system. And transfer function of the second order system is estimated by the dominant parameter which is computed in the magnitude and the phase of Fourier spectrum of the transformed signals. In addition, the output signal includes the unique feature of system. So, although the basic parameter of the system is unknown for us, the proposed method has an advantage to system modeling. And the controller is easily designed by the estimated transfer function. Thus, in this paper, the proposed method is applied to the system modeling for the position control system of DC Motor and the PD-controller is designed by the estimated model. And the efficiency and the reliability of the proposed method are verified by the experimental result.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.169-169
• /
• 2014

Interfacial electronic structure of bathocuproine and Al was investigated using in-situ photoemission spectroscopy and density functional theory (DFT) calculations. Bathocuproine is used for exciton blocking and electron transport material in organic photovoltaics and Al is typical cathode material. When thin thickness of Al was thermally evaporated on BCP, gap states were observed by ultraviolet photoemission spectroscopy. The closest gap state yielded below 0.3 eV from Fermi level. By x-ray photoemission spectroscopy, interaction of Al with nitrogen of BCP was observed. To understand the origin of gap states, DFT calculation was carried out and gap states was verified with successive calculation of interaction of Al and nitrogen of BCP. Furthermore, emergency of another state above Fermi level was observed. Remarkable reduction of electron injection barrier between Al and BCP, therefore, is possible.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.7
• /
• pp.1374-1378
• /
• 2008

Using DFT B3LYP/6-31+G(d,p)//B3LYP/6-31G(d,p) calculation method, stable molecular structures were optimized for the p-tert-butylcalix[4]arene functionalized at lower rim by cage-annulated crown ether (1) in two different conformers and their potassium-ion complexes. Cone conformer of free host 1 was slightly more stable than partial-cone conformer. For two different kinds of complexation mode, the potassium ion in benzene-rings (bz) pocket showed comparable complexation efficiency with the cation in cage-annulated crown-ether (cr) for the cone and partial-cone conformers of 1. The complex (1${\bullet}K^+$) in the cr-binding mode for the partial-cone conformer was more stable than the cone conformer for B3LYP/6-31G(d,p) geometry optimization. However, $1_{(cone)}{\bullet}K^+$(cr) showed lower single-point energy than the $1_{(pc)}{\bullet}K^+$(cr) for B3LYP/6- 31+G(d,p) calculation method.