• Proceedings of the KSME Conference
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• 2001.06a
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• pp.96-101
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• 2001

The development of a new experimental method is required to easily observe the growth behavior of fatigue cracks. To satisfy the requirement, an image processing technique was introduced to fatigue testing. The length of surface fatigue crack could be successfully measured by the image processing system. At first, the image data of cracks were stored into the computer while the cyclic loading was interrupted. After testing, crack length was determined using image processing software which was developed by ourselves. Block matching method was applied to the detection of surface fatigue cracks. By comparing the data measured by image processing system with the data measured by manual measurement with a microscope, the effectiveness of the image processing system was established. If the proposed method is used to monitor and observe the crack growth behavior automatically, the time and efforts for fatigue test could be dramatically reduced.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.81-88
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• 2005

The Langmuir monolayers of polyamic acid salts with three kinds of alkyl chains have been investigated by means of conventional $\pi$-A isotherms and second harmonic generation measurements proposed in this paper. The surface molecular density dependence of second harmonic intensity clearly shows the region of aggregation while corresponding $\pi$-A isotherm doesn't show any changes in the surface morphology at the same region. The surface morphology analysis based on the second harmonic measurement was consistent with the Brewster angle microscope measurement results.

• Journal of the Korean Applied Science and Technology
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• v.14 no.2
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• pp.35-40
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• 1997

The organization of phospholipid monolayers and their monolayers mixed with fatty acid containing azobenzene on the water surface was investigated by means of the displacement current measurement method. The phase transition from the gaseous phase to the gaseous-fluid phase which accompanies the polar ordering of phospholipid molecules was detected in the range of immeasurably low surface pressure. The molecular area which gives the onset of the transition was determined for phospholipid monolayers. The Maxwell displacement current(MDC) pulses were generated across mixed monolayers due to the photoisomerization of fatty acid containing azobenzene by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipids into the monolayers. The displacement currents generated during light irradiation were also investgated in connection with monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.6
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• pp.60-66
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• 1990

In order to measure the piston surface temperature and heat flux, autors have developed the measuring system with an instantaneous temperature probe. Such the instantaneous temperature probes were embodied into the top of piston for measurement and L-link system, designed to fit the test engine, extracts the thermocouple wires from the piston outside of engine employing a mechanical linkage. Then the instantaneous surface temperature was measured to calculate the heat flux flowing into the top surface of piston in a spark ignition engine. As a result, the following phenomena have been obtained through the study. 1) It is found that the time response and durability of temperature probe with a thin film thickness 10um and mechanical linkage with thermocouple wire extraction is sufficient at this experiment. 2) For the quantitative effect of variation in engine speed, the temperature swing and heat flux on the top of piston increase with increasing the engine speed. 3) It is proved that the temperature swing and heat flux decrease with distance from spark plug.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.141-150
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• 1998

The measurement of strains in stamped sheet metal is essential to the design and manufacture of sound sheet metal products. The measured strains can also be used in verifying the reliability of the computer analysis such as finite element analysis. In most engineering applications, strains are measured from the deformed square grids or deformed circular grids in comparison with the initial undeformed grids. In such a case, however, strains are averaged in each grid and the localized strain in a region smaller than a grid size can not be measured. In the present study, the B-spline surface interpolation technique is introduced in order to measure the strains more exactly and effectively. The strains calculated by using the surface interpolation technique are compared with the strains calculated from the three-noded grids as well as with the finite element analysis.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1516-1521
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• 2004

An inverse boundary analysis of surface radiation in an axisymmetric cylindrical enclosure has been conducted in this study. Net energy exchange method was used to calculate the radiative heat flux on each surface, and a hybrid genetic algorithm was adopted to minimize an objective function, which is expressed by sum of square errors between estimated and measured heat fluxes on the design surface. We have examined the effects of the measurement error as well as the number of measurement points on the estimation accuracy.

• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.309-314
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• 1999

This paper is concerned with the viscous interaction between rotor and stator The viscous interaction is caused by wakes from upstream blades. The cascade was composed with five blades and cylinders were placed to make wakes and their location was about 50 percent of blade chord upstream. The location of cylinders were varied in the cascade axis with 0, 20, 40, 60 and 80 percent of pitch length. The velocity distribution in the cascade passage were measured using single slanted hot-wire and the ones in the boundary layer using boundary probe. As a result, wakes decay more rapidly at suction surface and more slowly at pressure surface. And the measurement of momentum thickness of cascade shows that the momentum thickness is larger near the blade surface. From measurement of blade boundary layer, turbulent intensity is also larger near the blade surface because wakes collide the boundary layer And wakes make boundary layer thickness smaller and delay flow separation.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.2
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• pp.125-133
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• 1993

Electronic Speckle Pattern Interferometry(ESPI) using a CW laser, a video system and image processor was applied to the rotating displacement of rigid body. ESPI require no special surface preparation or attachments and displacements between any two arbitrary points on the surface can be measured. The characteristic speckle pattern formed when imaging a scattering surface illuminated by laser light retains phase information, which can be used for interferometric measurement of surface displacement. The application of this principle to measuring in-plane displacement resolved in one direction is described, together with the novel use of television equipment to detect and process the information contained in the speckle pattern. This is faster, and more convenient and versatile than customary photographic methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.404-405
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• 2007

Tin-doped indium thin film is outstanding material among transparent Conductive Oxide (TCO) materials. ITO thin films show a low electrical resistance(<$10^{-4}\;[{\Omega}{\cdot}m]$) and high transmittance(>80%) in the visible range. ITO thin films usually have been deposited on the glass substrate. In order to apply flexible display, the substrate should have the ability to bend and be deposited without substrate heat. Also properties of ITO thin film depend on what kind of substrate. In this study, we prepared ITO thin film on the polycarbonate (PC) substrate by using Facing Target Sputtering (FTS) system. Before deposition of ITO thin film, PC substrate took plasma surface treatment. The electrical and surface properties of as-deposited thin films were investigated by Hall Effect measurement, UV/VIS spectrometer and the surface property of substrate is investigated by Contact angle measurement.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.379-383
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• 2019

The capability of detecting amyloid beta 42 ($A{\beta}42$), a biomarker of Alzheimer's disease, using a thiolated protein A-functionalized bimetallic surface plasmon resonance (SPR) chip was investigated. An optimized configuration of a bimetallic chip containing gold and silver was obtained through calculations in the intensity measurement mode. The surface of the SPR bimetallic chip was functionalized with thiolated protein A for the immobilization of $A{\beta}42$ antibody. The response of the thiolated protein A-functionalized bimetallic chip to $A{\beta}42$ in the concentration range of 50 to 1,000 pg/mL was linear. Compared to protein A without thiolation, the thiolated protein A resulted in greater sensitivity. Therefore, the thiolated protein A-functionalized bimetallic SPR chip can be used to detect very low concentrations of the biomarker for Alzheimer's disease.