• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.140-143
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• 1997

It was investigated that space charge characteristics of EPDX/LPE laminates as a function of interfacial condition. There were no effects in charge accumulation characteristics at EPDM/XLPE laminate samples which were pasted with silicone oil and silicone grease. But when the crosslinking coagent (TMPTA) was pasted in laminate samples, there was no space charge in interface of EPDE/XLPE laminate and no effects in the laminate sample pasted with silicone grease dissolved crosslinking coagent. In the coupling agent pasted EPDhyXLPE laminate sample, space charge was accunlulated in XLPE side caused by coupling agent.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.4
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• pp.149-156
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• 2022

Magneto-Rheological Fluid (MRF) is a functional fluid in which flow characteristics change into magnetic force due to its magnetic particles. When the semi-active control device does not use MRF for a long time, precipitation of magnetic particles and abnormal control force occur. Thus, Electro Magneto-Rheological Fluid (EMRF), which improves the precipitation of magnetic particles for MRF and exhibits existing control performance, was developed in this study. First, the optimal mix proportion ratio was selected by conducting a precipitation experiment and a controlled force test by varying the content of grease based on the existing MRF components. Also, EMRF was applied to the shear-type damper to evaluate the control performance when applied to the control device. The cylinder-type damper was developed to apply to the structure, and control performance evaluation was conducted. The result confirmed that the precipitation of the magnetic particles was improved, while the damper using EMRF exhibited excellent control performance.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2005.10a
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• pp.153-170
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.23-24
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• 2012

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.159.2-159.2
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• 2009

• Journal of Korea Multimedia Society
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• v.22 no.11
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• pp.1280-1287
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• 2019

For developing a wireless implantable device to monitoring the artery variation in real-time. The concept of a special vessel variation measurement capacitive sensor is presented in this paper. The sensor consists of two part; main sensor to measuring the arterial variation, and reference sensor is used to improve the accuracy of the capacitance value variation. Before sensor manufacture, a model of the sensor attached on the artery was designed in 3D to conduct in the FEA simulation to validate the validity and feasibility of the idea. The artery model was designed as layered structures and made of collagenous soft tissues with intima inside, followed by the media and the adventitia. Also, a grease layer was designed in the inner of the arterial wall to imitate the clogged arteries. The simulation was divided into two parts; sensor performance test by changing the diameter of the grease layer, and arterial wall tension test by changing the blood pressure. As the simulation results, the capacitance value measured by the proposed sensor is decreased follow the diameter of the grease increased. Also, large elastic deformation of the arterial wall since changing the blood pressure has been observed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.733-737
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• 2007

The object of this paper is to propose a method to solve resulting heat in using numerous modulized watt-class LEDs in MCPCB as lighting device. To use LED for lighting, the chip needs to have a large capacity, resulting in extra heat in P-N connection area. To solve this problem, a Pottier Module, heat-sink panel and a fan was installed to measure variations in the temperature. Additionally, temperature variation characteristics were observed according to the heat conductor panel connecting cooling module and heat-sink panel, insulator and thermal grease. As a result, the type and amount of heat-sink panel was the most important facto. The fan would effect the temperature by max. $18[^{\circ}C]$ while other materials affected the temperature by $2{\sim}3[^{\circ}C]$, showing significant difference.

• Tribology and Lubricants
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• v.38 no.4
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• pp.170-178
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• 2022

Mechanical surface treatment is an excellent approach widely used to modulate and improve the performance and service life of bearings, gears, and frictional joints. The main purpose of this study is to investigate and compare the effect of ultrasonic nanocrystal surface modification (UNSM) and wonder process craft (WPC) on the surface and tribological properties of SUJ2 bearing steel. The surface roughness and hardness of the untreated and treated (UNSM- and WPC-treated) specimens were measured and compared. Their tribological properties were evaluated using a micro-tribometer under grease-lubricated and dry conditions against itself. Surface hardness measurement results revealed that both the UNSM- and WPC-treated specimens had a higher hardness than that of the untreated specimen. The surface roughness of the untreated specimen was reduced after UNSM and WPC treatments. Abrasive wear mode was observed on the surface of the specimens worn under grease-lubricated conditions, while adhesive wear mode was found on the surface of the specimens worn in dry conditions. According to the tribological test results, the friction coefficient and wear rate of the untreated specimens were reduced by the application of both the UNSM and WPC treatments under grease-lubricated and dry conditions.

• Journal of the Korean Chemical Society
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• v.45 no.1
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• pp.14-24
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• 2001

In order to study the long-term change of water quality, water analysis for 9 items was conducted at 13 sites surrounding the Kumho river system for 18 times from September 1993 to August 1999. Analytical items for the study of water quality are as follows; water temperature, pH, BOD, COD, DO, SS, electrical conductivity, oil and grease, ABS and phenol. The six year term was divided into Part I(second study) and Part Ⅱ(third study), which covers the term from September 1993 to August 1996 and the term from September 1996 to August 1999, respectively. The mean values obtained for three years for water temperature, pH, BOD, COD, DO, SS, electrical conductivity, oil and grease, ABS and phenol for the Part I period showed 18.4$^{\circ}C$, 7.9, 4.88 ppm, 9.66 ppm, 9.0 ppm, 618.0 umho/cm, 6.9 ppm, 2.63 ppm, 3.57 ppm and 0.98 ppm, respectively. The mean values obtained for water temperature, pH, BOD, COD, DO, SS, electrical conductivity, oil and grease, ABS and phenol for the Part Ⅱ period showed 18.0$^{\circ}C$, 8.0, 2.86 ppm, 7.40 ppm, 8.94 ppm, 541.0 umho/cm, 6.0 ppm, 5.43 ppm, 0.94 ppm and 0.01 ppm respectively. The values of BOD, COD, SS, electrical conductivity, ABS and phenol in the second period were found to be decreased by 1/1.71, 1/1.31, 1/4.15, 1/3.80 and 1/98, respectively. The values of water temperature, pH and DO were nearly constant. However, the concentrations of oil and grease were found to be increased about 2.06 times in the second period.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1653-1660
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• 2004

This study was conducted to investigate seasonal changes of microbiological counts and sanitation state on the surface of food service facilities and utilities of elementary schools in Busan area. Samples swabbed using sponge were collected from the surface of food service facilities and utilities, that is ceiling, wall, floor, trench, grease trap, hood, pest control net and dumb waiter, and analyzed by measuring the total plate, coliform and Salmonella spp. count. The total plate counts at foodservice facilities and utilities except ceiling and wall were ranged from 10$^4$∼10$^{6}$ CFU/100 $\textrm{cm}^2$. The coliform counts were ranged from 10$^2$∼10$^4$ CFU/100 $\textrm{cm}^2$ at foodservice facilities and utilities except ceiling. The grease trap was the severely contaminated facility. It was indicated that the sanitary condition at the foodservice facilities and utilities except ceiling and wall should be improved promptly. As a result of investigating the seasonal changes of microbiological counts, floor, trench, grease trap and dumb waiter should be carried out disinfection before foodserving everyday in summer season, and the disinfection frequencies of wall, hood and pest control net should not be less than three times per week. In winter season floor, trench, and dumb waiter should be carried out disinfection after foodserving, grease trap should be carried out disinfection before foodserving everyday and the disinfection frequencies of wall, hood and pest control net should not be less than twice per week.