• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.274-278
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• 2000

Ball end milling process is widely used in the die and mould manufacturing because of suitableness for the machining of free form surface. But, as ball end mill is long and thin, it is easily deflected by cutting force. In this study, Cutting force, tool deflection and surface precision was measured according to the change of depth and cutting location. Cutting force was acquired with tool dynamometer and a couple of eddy-current sensor measured tool deflection in x-y direction each. After machining, surface precision was measured with roundness tester and coordination measuring machine for sculptured surface angle change and cutting depth.

• International Journal of Oral Biology
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• 제39권4호
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• pp.187-192
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• 2014

Nonthermal atmospheric pressure plasma has attracted great interest for biomedical applications. The plasma consists of charged particles, radicals, and a strong electric field as the fourth state of matter. This study evaluated the change in the surface roughness after tooth bleaching by plasma in combination with a low concentration (15%) of carbamide peroxide, specifically whether the application of plasma produced detriments, such as demineralization and structural change, with the goal of efficient and safe tooth bleaching. After being combined with plasma and 15% carbamide peroxide, the hydroxyapatite surface was significantly smoother with a low roughness average value. Tooth bleaching with 15% carbamide peroxide alone produced an irregular surface and increased the surface roughness with high roughness average value. Tooth bleaching with plasma resulted in no significant variations in hydroxyapatite in terms of change in surface roughness and surface topography. The application of tooth bleaching with plasma is not deleterious to dental hard tissue, implicating it as a safe tooth bleaching technique.

• 대한기계학회논문집
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• 제14권3호
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• pp.617-623
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• 1990

본 연구에서는 표면방향과 깊이 방향으로 표면균열의 피로성장률이 다르게 나 타나고 있는 경우의 표면균열 형상변화를 표면균열의 균열 열림을 고려하여 해석할 수 있는 식이 수정 제안되었으며, 압력용기 소재에서 측정된 표면균열의 형상변화와 본 연구에서 제안된 형상 변화식에 의한 예측과 비교 분석하였다. 또한 균열 성장과 형 상변화를 평균 응력강도계수에 대해 분석하였고 다른 표면균열 형상 변화식들에 의한 표면균열 형상변화해석이 같이 비교 검토되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.486-486
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• 2013

Silicon nanowire devices fabricated by bottom-up methods are attracted due to their electrical, mechanical, and optical properties. Especially, to functionalize the surface of silicon nanowires by molecules has received interests. The changes in the characteristics of the molecules is delivered directly to the surface of the silicon nanowires so that the silicon nanowire can be utilized as an efficient read-out device by using the electronic state change of molecules. The surface treatment of the silicon nanowire with light-sensitive molecules can change its optical characteristics greatly. In this paper, we present the optical response of a SiNW field-effect-transistor (FET) conjugated with porphyrin molecules. We fabricated a SiNW FET and performed porphyrin conjugation on its surface. The characteristic and the optical response of the device shows a large difference after conjugation while there is not much change of the surface in the SEM observation. It attributed to the existence of few layer porphyrin molecules on the SiNW surface and efficient variation of the surface potential of the SiNW due to light irradiation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.979-982
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• 2003

In this study, because of change in electromagnetic force, deformation of the free surface motion of a magnetic fluid is changed. Deformation of the free surface motion of a magnetic fluid for the change in electromagnetic force is discussed and carried out theoretically and experimentally on the basis of Rosensweig Ferrohydrodynamic Bernoulli Equation. Objective of this study explicates free surface motion by electromagnetic force and planes to designed controller. To control free surface of magnetic fluid, it embody designed two-dimensional free surface form of magnetic fluid. By using this characteristics, they applied to oscillator for surface control, flow control, boundary layer control. Strength of magnetic field and height of free surface of magnetic fluid measure as a hall-effect sensor. As performing height control of magnetic fluid, the result will be presented possibility of free surface deformation control.

• 한국의류학회지
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• 제20권3호
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• pp.467-480
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• 1996

Interactions between PET POY and solvents were estimated by the changes in microstructure and surface morphology. Changes in microstructure and surface morphology by the solvent treatments were: an increase in crystallite size, a decrease in interplanar spacing, a change in degree of orientation of crystalline region, a change in surface characteristics.

• 대한치과보철학회지
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• 제37권3호
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• pp.343-357
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• 1999

The color change of maxillofacial silicone has been attributed to certain environmental factors such as exposure to the UV component of natural sunlight, wetting and drying of the elastomer and surface abrasion resulting from the application and removal of cosmetics. The purpose of this study was to evaluate the color change of maxillofacial silicone (Silastic MDX4-4210) according to type of pigment (cadmium yellow, titanium white, cosmetic red), and UV absorber application method after 200, 400, and 600 hours of 350nm UV light irradiation. The results were as follows. 1. According to type of pigments, after 200 hours cosmetic red showed significantly larger color change than cadmium yellow and titanium white, and after 400 and 600 hours color change significantly decreased in the order of cosmetic red, cadmium yellow, and titanium white (p<0.05). 2. In the cadmium yellow group, after 200 hours, the non-treatment group showed significantly larger color change, but after 400 and 600 hours, color change significantly decreased in the order of non-treatment, surface application and mixed group (p<0.05). 3. In the titanium white group, there was no significant color change difference between the three groups after 200 and 400 hours, but after 600 hours, the mixed group showed significantly smalt or color change than the non-treatment and surface application groups (p<0.05). 4. In the cosmetic red group, there was significant decrease in color change in the order of non-treatment, surface application and mixed group (p<0.05). From the results above, the effect of UV light absorber differed according to the type of pigment, but mixing UV light absorber with maxillofacial silicone is thought to give superior resistance against UV light irradiation in the long run.

• 한국대기환경학회지
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• 제28권3호
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• pp.249-260
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• 2012

Monitoring of climate change and atmospheric environment by satellite measurements has been increased in recent years. In this study, nitrogen dioxide ($NO_2$) measurements from Ozone Monitoring Instrument (OMI) were compared with surface measurements over the Korean peninsula. $NO_2$ from OMI measurements showed high values and also showed seasonal variations such as high concentration in winter and low in summer over metropolitan areas while $NO_2$ concentration at national background station was low and did not clearly show seasonal variations. Surface measurements showed similar temporal and spatial variations to those of satellite measurement. The comparison between satellite measurements and surface measurements showed that the correlation between them was higher in urban area (r=0.64 at Seoul and r=0.63 at Daegu) than in national background stations (r=0.37 at Jeju) because the concentration in urban area was relatively high so that the variation of $NO_2$ concentration could be detected better than at national background stations by satellite. Satellite can effectively measure the emission and transport of pollutants with no limitations in spatial coverage.

• Ocean and Polar Research
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• 제24권3호
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• pp.207-213
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• 2002

We have analyzed sea surface temperature and salinity data collected in the western Pacific Ocean by using an automated Thermosalinograph (TSG) installed on the RV Onnuri during May - June of 2001. The TSG data exhibit characteristics of water masses distributed in the near surface layer of the cruise area very well. Especially, they reveal the diurnal surface temperature cycle and the effect of rainfall on temperature and salinity in the equatorial region, showing the effectiveness of the use of TSG. Problems to be improved for the better TSG operation are the method of water sampling and calibration of TSG sensors. Installation of a pressure gauge in the TSG system and periodical sensor calibration are strongly recommended to ensure reliability of data.

• 한국의류학회지
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• 제14권4호
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• pp.292-304
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• 1990

The surface change of upperarm and shoulder blade area are caused by the extensive upper limb movement, thus it is necessary to measure the amount of change for constructing the clothing. Moire photography was taken after plastic casters of upperarm and shoulder blade area was prepared. 1. For the shoulder blade area, subjects showed the same change of surface area for the various limb positions, wherease, for the upperarm only at the $0^{\circ}\;and\;180^{\circ}$ limb position, same change was observed. 2. As the movement of the upperarm was increased, surface area of axillary part was increased and that of shoulder part was decreased. 3. To make a bodice pattern, the minimum size of the back with the ease were $\frac{B}{4}$+3.13 cm R for normal wear and $\frac{B}{4}$+5.75 cm for active wear. 4. As the movement of the arm was increased, the cross section for the upperarm were changed to elliptical shape. 5. For each horizontal basic line, there was a positive correlation between the amount of change of shoulder blad area and that of upperarm area.