Jecheon, South Korea
Jecheon, South Korea

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Kang J.W.,Korea University | Kwon O.K.,Semyung University
Applied Surface Science | Year: 2012

We investigated tunable gigahertz-resonators, which is based on the application of a telescoped double-walled carbon-nanotube that can be used repeatedly and operate at a single frequency or have a relatively narrow frequency range, via classical molecular dynamics simulations of a double-walled carbon-nanotube. Two types of telescoped double-walled carbon-nanotube resonators were compared with each other; one was bridge-type and another was cantilever-type, and one side was connected to a position controller in order to achieve a telescoped carbon-nanotube. The frequency bandwidth of our cantilevered type design can exceed that of the bridged type. Our simulations showed that such a system can tune it up its resonance frequency by controlling the length of oscillating carbon-nanotube resonator. © 2011 Elsevier B.V. All rights reserved.

Park S.,Semyung University | Shin W.-S.,Hanyang University
Physiology and Behavior | Year: 2015

This study aimed to determine whether there might be differences in masticatory performance and eating behaviors by gender and obesity status. Forty eight (24 males; 24 females) non-obese and pre-obese young adults were matched for age, gender, and dental health. Eating behaviors were assessed using the Three-Factor Eating Questionnaire (TFEQ), and chewing performance while eating 152. g of boiled rice was measured using electromyography (EMG). Compared with non-obese participants, pre-obese participants had significantly higher levels of disinhibition according to the TFEQ (P < 0.05 for males; P. < 0.01 for females). Microstructures of chewing performance were significantly different by gender but not by obesity status. Males had a greater bite size (P < 0.05), greater chewing power (P < 0.001) and a faster eating rate (P < 0.05) than females. Females habitually chewed more (P < 0.05) and had a longer meal duration (P < 0.01) than males. Eating rate was positively associated with disinhibition (r=0.490, P. < 0.05) score in males. Bite size (r=- 0.449, P. < 0.05 for non-obese) and chewing power (r=- 0.581, P. < 0.01 for non-obese and r=- 0.446, P. < 0.05 for pre-obese) were negatively associated with disinhibition score. Results suggest that the effects of gender and, in part, obesity on eating responses may be explained as chewing performance. Therefore, gender-specific interventions and counseling aimed at slowing the rate of ingestion could be promising behavioral treatments for obese persons. © 2014 Elsevier Inc.

Kim Y.J.,Korea Institute of Construction Technology | Choi Y.W.,Semyung University
Construction and Building Materials | Year: 2012

This study is conducted to utilize waste concrete powder (WCP) made as a by-product manufacturing high quality recycled aggregate. The Blaine fineness of the WCP used was 928 and 1360 cm 2/g. As the main characteristic of WCP, it is particle were angular similar to cement, and hydrated products were attached on the surface of particles. In addition, the particle size of WCP was larger than Ordinary Portland Cement (OPC) and in terms of chemical components it had higher SiO 2 content. The viscosity of pastes that contained WCP decreased by up to 62% compared to paste that only used OPC, and the final set time was delayed about 2 h. As substitution rates of WCP increased, the flow value decreased by 30% at the most according to the comparison with mortar that only used OPC. The compressive strength of mortar decreased by up to 73% as level of WCP increased and sorptivity coefficients increased by 70%. According to the test results, it is desirable to keep WCP replacement OPC to below 15%. © 2011 Elsevier Ltd. All rights reserved.

Lee K.M.,Semyung University
Lecture Notes in Engineering and Computer Science | Year: 2013

A home network system with some electric devices was constructed with a power line communication method. The system had two kinds of modems, a central-side and a receive-side. The central-side modem was connected to a controller computer, and the receive-side modem was connected to the electric devices, which were operated by the computer. The devices' setup statuses were manipulated by an external voice recognition controller which was used as a user interface, and connected via Bluetooth communication to the serial port of the computer's COM6. The Bluetooth and the power line communication data rates were 9600 bps and 2400 bps, each. The Polling Process Technique was used for the computer to read the voice recognition result, and to send home-electric-device controlling data to the receive-side modems. The command-recognizing time of the controller was depended on the number of commands. For five commands, the responding time of the communication between the computer and the voice board, was less than 110 milliseconds. Also, the response time of the communication between the computer and the receive-side modem, was less than 100 milliseconds. The home electric device statuses were shown graphically on the computer screen according to the device's setup conditions. It was much more convenient to use a voice command than a key board or a mouse.

The aim of this study was to provide accurate anatomical descriptions of the overall anatomy of the superior thyroid artery (STA), its relationship to other structures, and its driving patterns. Detailed dissection was performed on thirty specimens of adult's cadaveric neck specimens and each dissected specimen was carefully measured the following patterns and distances using digital and ruler. The superior thyroid, lingual, and facial arteries arise independently from the external carotid artery (ECA), but can also arise together, as the thyrolingual or linguofacial trunk. We observed that 83.3% of STAs arose independently from the major artery, while 16.7% of the cases arose from thyrolingual or linguofacial trunk. We also measured the distance of STA from its major artery. The origin of the STA from the ECA was 0.9±0.4 mm below the hyoid bone. The STA was 4.4±0.5 mm distal to the midline at the level of the laryngeal prominence and 3.1±0.6 mm distal to the midline at the level of the inferior border of thyroid cartilage. The distance between STA and the midline was similar at the level of the hyoid bone and the thyroid cartilage. Also, when the STA is near the inferior border of the thyroid cartilage, it travels at a steep angle to the midline. This latter point may be particularly important in thyroidectomies. We hope that anatomical information provided here will enhance the success of, and minimize complications in, surgeries that involve STA. © 2016. Anatomy & Cell Biology.

Cho S.,Semyung University
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2016

Conics and Cartesian ovals are extremely important curves in various fields of science. In addition, aspheric curves based on conics are useful in optical design. Superconic curves, recently suggested by Greynolds, are extensions of both conics and Cartesian ovals and have been applied to optical design. However, they are not extensions of aspheric curves based on conics. In this work, we investigate another type of superconic curves. These superconic curves are extensions of not only conics and Cartesian ovals but also aspheric curves based on conics. Moreover, these are represented in explicit form, while Greynolds's superconic curves are in implicit form. © 2016 Optical Society of America.

Jung J.-S.,Semyung University
International Journal of Bio-Science and Bio-Technology | Year: 2014

Volatile components in the root peels, stem peels, and fruit peels of pomegranate (Punica granatum) were analyzed by thermal desorption gas chromatography/mass spectrometry (TD GC/MS). Twenty-four compounds including 17 hydrocarbons, 1 aldehyde, 1 ketone, 2 heterocyclics, and 3 others were identified in the root peels. Thirty compounds including 5 hydrocarbons, 8 alcohols, 3 aldehydes, 2 ketones, 11 esters, and 1 other were identified in the stem peels. Sixty-two compounds including 10 hydrocarbons, 18 alcohols, 6 aldehydes, 4 ketones, 1 carboxylic acid, 17 esters, 1 heterocyclic, and 5 others were identified in the fruit peels. Monoterpene hydrocarbons such as α-pinene (13.49%), 2-β-pinene (16.31%), δ-3-carene (22.94%), and dl-limonene (17.33%) were found to be the major volatile compounds in the root peels. The main volatile compound in the stem peels and fruit peels was ethanol of alcohol, which represented 40.76% and 42.12% of the total concentration of volatiles, respectively. Other compounds dominating the stem peels and fruit peels were all acetic acids and ethyl ester of ester, which represented 21.29% and 19.59% of the total concentration of volatiles, respectively. © 2014 SERSC.

In this study, Li 0.02(Na 0.55K 0.45) 0.98[(Nb 0.77Ta 0.18Sb 0.05) 1-2x/5Cu x]O 3 (LNKNTS-x Cu) piezoelectric ceramics with x = 0-0.015 were fabricated by conventional solid-state reaction method. The temperature stability of k p was investigated. At the sintering temperature of 1120°C and 0.6 mol% Cu content, the optimum values of density = 4.808 g/cm 3, k p = 0.446, Q m = 109, ε r = 1359 and d 33 = 254 pC/N, were obtained, respectively. Taking into consideration above physical properties, it is considered that this composition is applicable to lead-free haptic piezoelectric actuators with good temperature stability in the temperature range of-20 to 80°C. © 2012 Elsevier B.V. All rights reserved.

Lee K.S.,Semyung University | Yoo J.H.,Semyung University
Current Applied Physics | Year: 2012

In the study, in order to develop the lead-free piezoelectric ceramics for actuator, transformer and other electronic-devices application, (K 0.5Na 0.5)(Nb 0.9+xTa 0.1)O 3 + 0.5 mol% CuO + 0.2 mol% MnO 2 ceramics were prepared by conventional mixed oxide method. The effects of B-site non-stoichiometry in [(K 0.5Na 0.5)] [(Nb 0.9+xTa 0.1)O 3] ceramics on microstructure and piezoelectric properties were investigated. The density, electromechanical coupling factor (k p), mechanical quality factor (Q m), piezoelectric constant (d 33), T C and T O-T of NKNT ceramics with x = 0.0065 showed the optimum values of 4.58 g/cm 3, 0.427, 1554, 109 pC/N, 373°C and 226°C, respectively, suitable for piezoelectric motor, and transformer applications. © 2011 Elsevier B.V. All rights reserved.

The alkaline niobate-based perovskite ceramics (Li,Na,K)(Nb,Ta,Sb)O 3 has been regarded as a new candidate of lead-free piezoelectric materials due to its excellent piezoelectric properties. In this study, Li 0.02(Na0.55K0.45)0.98(Nb 0.77Ta 0.18 Sb0.05)O3 (abbreviated as LNKNTS) piezoelectric ceramics were fabricated by a conventional solidstate reaction method at various calcinations temperature and then, their dielectric and piezoelectric properties were investigated. At the calcinations temperature of 870°C and sintering temperature of 1140°C, the optimum values of density = 4.736g/cm3, kp = 0.423, Qm = 65, εr = 1545 and d33 = 256 pC/N, were obtained, respectively. Taking into consideration above physical properties, it is considered that this composition is applicable to lead-free haptic piezoelectric actuators. Copyright © Taylor & Francis Group, LLC.

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