• Science of Emotion and Sensibility
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• v.15 no.1
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• pp.9-16
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• 2012

Generally, cosmetic creams have been used to moisturize and smooth human skin. Recently, people concerns about the creams released with natural flavors and its functionality. This study focused to assess the psychophysiological effects of creams with 5 natural flavors such as patchouli oil, frankincense, sandalwood oil, none and newly developed S6. Initially, we have performed subjective evaluation for 100 female subjects aged 20 to 30 from Daejeon, South Korea. The results showed the most preferred flavor was S6 condition. Second, physiological evaluations for 20 female subjects were measured with EEG, ECG and GSR. In EEG analysis, the alpha ratio was confirmed to appear higher in each condition. The statistical analysis shows that significantly largest effect at S6 condition($p$ <0.05). The result from ECG and GSR measurements also shows the same trend. Third, skin conditions were measured when using S6. As a result, the skin temperature, humidity and skin movement speed were increased with S6 condition. The moisturizing and elasticity effects were confirmed.

• Journal of Sericultural and Entomological Science
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• v.53 no.2
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• pp.101-109
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• 2015

To extend shelf life of mulberry fruits, usually expensive freeze drying of freezing process is required. In this study an economic to multipurpose agricultural products dryers with mulberry dryer and technique was developed to reduce postharvest processing cost. Fuel and electricity consumption for drying were lowest when drying temperature was $60^{\circ}C$. And various drying conditions (fuel 3 hrs, heat 1 hr, room temperature air velocity 51 hrs) of the developed dryer were analyzed to improve drying performance. Dried mulberry fruits had dark brown color and marketable high quality explain the semi-dried characteristics.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.131-136
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• 2021

A DC motor is an important driving source used in a wide range along with an induction motor. Although the structure is complex and has disadvantages in terms of maintenance, most of the demands are given to induction motors as a power source in the industry today, but due to its excellent control performance, DC motors are constantly being used as small-sized control motors. In addition, DC motors with a structure capable of high-power and high-efficiency operation are being developed with the development of magnetic materials as a structure capable of using a permanent magnet in a armature. In addition, the configuration of the controller is simpler than that of an induction motor using an inverter, and the demand for a DC motor is still not negligible, so it is still occupied as an important power source. Considering these trends, this paper attempts to investigate the control performance of DC motors through hardware implementation such as modeling through simulation, PWM generation circuit and electric motor circuit using EPLD, and PI control using processor.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.4
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• pp.129-134
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• 2021

A power tool is a tool used to manufacture and process various structures using a motor that is a power source. Using a motor that uses electricity as a power source, a reduction device, power transmission and conversion device functions are built-in to make the tool rotate, reciprocate, and vibrate. It is a work tool designed to assist the user's movement skills. In the case of Korea, the power tool industry has a short history and is lagging behind advanced countries such as Germany, the United States, and Japan in terms of technology level, market share, and recognition. In addition, electric drivers used in Korea are foreign products from the US and European countries, and the domestic market also prefers 100% foreign companies, and multinational companies are investing a lot in the domestic market. Therefore, technological development must follow in order to develop domestic technology and secure a consistently high market share. The purpose of this thesis is to design a motor driver with high output performance of motor performance, miniaturization, and high speed in accordance with the basic performance requirements of power tools, and finally research developments that can be applied to industrial and medical applications.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.677-682
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• 2023

A large number of motors and sensors are used to drive a humanoid robot. In order to solve the wiring problem that occurs when connecting multiple actuators, a controller based on a communication network has been used, and CAN, which is advantageous in terms of cost and a highly reliable communication protocol, was mainly used. In terms of the structure of the controller, a torque control type structure that is easy to implement an advanced algorithm into the upper controller is preferred. In this case, the low communication bandwidth of CAN becomes a problem, and in order to obtain sufficient communication bandwidth, a communication network is configured by separating into a plurality of CAN networks. In this study, a stability analysis on transmission time delay is performed for a multi-motor control system in which high-speed FlexRay and low-speed CAN communication networks are hierarchically connected in order to obtain a high communication bandwidth, and sensor information and driving signals are delivered within the allowed transmission time. The proposed hierarchical network-based control system is expected to improve control performance because it can implement multiple motor control systems with a single network.

• Transactions of Materials Processing
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• v.33 no.3
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• pp.200-207
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• 2024

In this study, we developed a semi-analytical approach for the numerical analysis of residual stress in oxide scales formed on hot-rolled steels. The oxide scale, formed during the hot rolling process, experiences complex interactions due to thermal and mechanical influences, significantly affecting the material's integrity and performance. Our research focuses on integrating various stress components such as thermal stress, growth stress, and creep behavior to predict the residual stress within the oxide layer. The semi-analytical method combines analytical expressions for each stress component with numerical integration to account for their cumulative effects. Validation through instrumented indentation tests confirms the reliability of our model, which considers thermal expansion coefficient (CTE) differences, scale growth, and creep-induced stress relaxation. Our findings indicate that thermal stress resulting from CTE differences significantly impacts the overall residual stress, with growth stress contributing a compressive component during cooling, and creep behavior playing a minor role in stress relaxation. This comprehensive approach enhances the accuracy of residual stress prediction, facilitating the optimization of material design and processing conditions for hot-rolled steel products.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.5
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• pp.398-402
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• 2012

Synthesis of $Li_2MnSiO_4$ was attempted by the conventional solid-state reaction method, and the phase formation behavior according to the change of the calcination condition was investigated. When the mixture of the three source materials, $Li_2O$, MnO and $SiO_2$ powders, were used for calcination in air, it was difficult to develop the $Li_2MnSiO_4$ phase because the oxidation number of $Mn^{2+}$ could not be maintained. Therefore, two-step calcination was applied: $Li_2SiO_3$ was made from $Li_2O$ and $SiO_2$ at the first step, and $Li_2MnSiO_4$ was synthesized from $Li_2SiO_3$ and MnO at the second step. It was easy to make $Li_2MnSiO_3$ from $Li_2O$ and $SiO_2$. $Li_2MnSiO_4$ single phase was developed by the calcination at $900^{\circ}C$ for 24 hr in Ar atmosphere as the oxidation of $Mn^{2+}$ was prevented. However, the $Li_2MnSiO_4$ was ${\gamma}-Li_2MnSiO_4$, one of the polymorph of $Li_2MnSiO_4$, which could not be used as the cathode materials in Li-ion batteries. By applying the additional low temperature annealing at $400^{\circ}C$, the single phase ${\beta}-Li_2MnSiO_4$ powder was synthesized successfully through the phase transition from ${\gamma}$ to ${\beta}$ phase.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1116-1122
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• 2009

ATS(Automatic Train Stop) system makes train stop when it runs over the speed limit and ensure the safe operation of train. Seoul Metro line 2 in Korea, which started its passenger service in 1982, has adopted ATS system for its signaling system. The ATS system has only a train stop function at the time of emergency, and Seoul Metro is planning to replaced them with ATC(Automatic Train Control)/ATO(Automatic Train Operation) system which can provide the dedicated speed control for headway reduction and automatic operation of train. Until all the ATS system is replaced with the new ATC system, both systems are to operate simultaneously at the same metro line. In this situation, ATS system sometimes reveals improper operation: train stops suddenly without any obstacles in front of it. These emergency stops cause interruption of passenger service, and abnormal abrasion of wheels and rail. This paper makes it clear that these interruptions are caused by EMI phenomena between ATS on-board device and ATC wayside device : Signal current flowing in AF track circuit of ATC is turn out to be a EMI source that prevent normal operation of the ATS on-board device. Although the two systems have different frequency-ranges (ATS system has frequency range between $78{\sim}130$[kHz] and ATC system has frequency range between $9.5{\sim}16.5$[kHz]), it turned out that EMI phenomena appears between the both systems. This is investigated by measuring the output signal from ATS on-board device passing over ATC wayside device. The FFT(Fast Fourier Transform) analysis of the signal reveals that AF track circuit signal is transmitted to the ATS on-board device and induce noise causing improper operation. The countermeasures to the EMI phenomena are examined in three ways; blocking EMI transmission, enforcement of EMS (Electromagnetic Susceptibility) of ATS on-board device, and blocking the EMI source. It is suggested that the practical solution be blocking EMI source temporarily, that is breaking AF track circuit signal when the trains with ATS on-board device pass over it. To this purpose, TODS(Train Occupation Detection System) is developed, and has made a success in preventing the EMI problem of Seoul Metro line 2.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.699-704
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• 2018

One-dimensional nanostructures have attracted increasing attention because of their unique electronic, optical, optoelectrical, and electrochemical properties on account of their large surface-to-volume ratio and quantum confinement effect. Vertically grown nanowires have a large surface-to-volume ratio. The vapor-liquid-solid (VLS) process has attracted considerable attention for its self-alignment capability during the growth of nanostructures. In this study, vertically aligned silicon oxide nano-pillars were grown on Si\$SiO_2$(300 nm)\Pt substrates using two-zone thermal chemical vapor deposition system via the VLS process. The morphology and crystallographic properties of the grown silicon oxide nano-pillars were investigated by field emission scanning electron microscopy and transmission electron microscopy. The diameter and length of the grown silicon oxide nano-pillars were found to be dependent on the catalyst films. The body of the silicon oxide nano-pillars exhibited an amorphous phase, which is consisted with Si and O. The head of the silicon oxide nano-pillars was a crystalline phase, which is consisted with Si, O, Pt, and Ti. The vertical alignment of the silicon oxide nano-pillars was attributed to the preferred crystalline orientation of the catalyst Pt/Ti alloy. The vertically aligned silicon oxide nano-pillars are expected to be applied as a functional nano-material.

• Resources Recycling
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• v.19 no.5
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• pp.68-74
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• 2010

The aim of this study is to investigate the behaviors of synthesis of Calcium Chloroaluminte($11CaO{\cdot}7Al_2O_3{\cdot}CaCl_2$) under the melting temperature of municipal solid waste incineration fly ash(MSWI fly ash); $900^{\circ}C-1300^{\circ}C$ of sintering temperature. A sludge generated from a water purification plant (SW) was also used to fill up $Al_2O_3$ source, which might be deficient in MSWI fly ash. MF and SW were mixed at mixing ratio of 10 to 7, which is the mole ratio of CaO to $Al_2O_3$ of calcium Chloroaluminte. Mixed samples were sintered in the opened sintering reactor and the closed sintering reactor, respectively. The results showed that calcium chloroaluminte was formed at $1,000^{\circ}C$ in both reactors, but the temperature of decomposition of calcium chloroaluminte depended upon sintering reactor type; an opened sintering reactor and a closed sintering reactor, owing to the vaporization velocity of Cl.