• Journal of Adhesion and Interface
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• v.2 no.1
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• pp.31-43
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• 2001

• Proceedings of the Korean Society of Rheology Conference
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• 2001.06a
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• pp.77-80
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• 2001

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3
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• pp.447-451
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• 2013

In this study, a shock absorber whose orifice area changes according to the oil pressure inside the absorber is developed. The orifice widens and narrows when the oil pressure is high and low, respectively; thus, the orifice area changes according to the oil pressure, in other words, according to the extension/compression velocity. It is well known that the damping force can be expressed as $C{\cdot}v^{\alpha}$. For fluid film damping, the force is proportional to velocity, i.e., ${\alpha}=1$, and for orifice damping, it is proportional to the square of velocity, i.e., ${\alpha}=2$. The shock absorber proposed in this paper can exhibit different relationships between the damping force and velocity because the orifice area changes according to the induced oil pressure. The motivation of this study is to develop a method for designing a shock absorber with desired values of C and ${\alpha}$ which is not just 1 or 2. Theoretical and experimental studies have been conducted to verify the damping characteristics of the shock absorber. The effect of some major design parameters on damping characteristics has been also examined to relate the design parameters to the damping characteristics.

• Journal of Wellbeing Management and Applied Psychology
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• v.2 no.2
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• pp.13-19
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• 2019

This study is about pressure-accepting behavior of consumers attached to brands. Previous studies of the situation focused on time pressure and scarcity pressure, focusing on scarcity. The results of the study are as follows. First, consumers attached to brands were found to be relatively blunt in time pressures. This indicates that brands of consumers are attached to do not buy on impulse because of time pressure. Second, consumers attached to brands were found to be relatively under social pressure. This indicates that consumers who are attached to the brand do not buy with social pressures such as quasi-family groups. Third, consumers attached to brands were found to be relatively sensitive to scarcity pressures. Thus, a quantity-limited marketing strategy is generally more effective for consumers with high marketing effectiveness but high brand attachment. Fourth, unlike the one presented, consumers attached to the brand were found to be relatively insensitive to place pressure.

• Journal of Sensor Science and Technology
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• v.10 no.3
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• pp.173-179
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• 2001

The currently used semiconductor pressure sensors are piezoresistive and capacitive type. Especially, semiconductor micro pressure sensors have a great deal of attention because of their small size. However, its fabrication processes are difficult, so that its yield is poor. For the purpose of resolving the drawbacks of the existing silicon pressure sensors, we demonstrate a new type of pressure sensor using PSFET(pressure sensitive field effect transistor) and investigate its operational characteristics. We used PZT(Pb(Zr,Ti)$O_3$) as a pressure sensing material. PZT thin films were deposited on a gate oxide of MOSFET by an rf-magnetron sputtering method. To abtain the stable phase, perovskite structure, furnace annealing technique have been employed in PbO ambient. The sensitivity of the PSFET was 0.38 mV/mmHg.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.3
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• pp.578-597
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• 2014

Understanding of 'spatial' pressure distribution is required to determine design loads on local structures, such as plating and framing. However, obtaining a practical 'spatial' pressure distribution is a hard task due to the sensitivity of the data acquisition frequency and resolution. High-resolution Pessure-Idicating Flm (PIF) was applied to obtain pressure distribution and pressure magnitude using stepped crushing method. Different types of PIF were stacked at each test to creating a pressure distribution plot at specific time steps. Two different concepts of plotting 'spatial' pressure-area curve was introduced and evaluated. Diverse unit pixel size was chosen to investigate the effect of the resolution in data analysis. Activated area was not significantly affected by unit pixel size; however, total force was highly sensitive.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1314-1317
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• 1997

For realizing artificial skin sensing as a final goal, a mono-material pressure-conductive rubber sensor which is also sensitive for temperature is described. Firstly, discimination of the hardness and the thermal property of material using a proposed sensor is presented. Furthermore, a tactile sensor constints of four pressure-conductive rubber sensor to discriminate surface model which imitaties the surface roughness of material is proposed.

• Journal of the Korean Society of Visualization
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• v.9 no.1
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• pp.36-41
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• 2011

It is highly needed to measure the dissolved oxygen (DO) concentration field in water for a variety of purposes such as biological, industrial, environmental monitoring and medical application. Application of PSP (Pressure Sensitive Paint) which is sensitive to oxygen concentration has been carried out to measure DO concentration field using PtOEP/PS film and intensity based method under the UV-LEDs illumination. A micro round water jet having 100% of DO was obliquely impinged on to a PtOEP/PS film coated plate placed in a 0% of DO water container. DO concentration fields on the impinging plate were quantitatively visualized with a $2.94\;{\mu}m$ of spatial resolution. Through pixel-by-pixel calibration, uncertainty of each pixel by different sensitivity, different dye concentration and non-uniformity of illumination was removed. It is demonstrated that the high DO concentration region was coincided with the impingement area. The DO concentration gradient due to DO diffusion was affected by Reynolds number.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.409-410
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• 2002

In order to measure the oil-film pressure in sliding surface of machinery, we have developed a piezo-resistive type thin-film pressure sensor. To reduce the measurement error due to temperature and strain, the constituent of the pressure sensitive alloy was optimized and a new sensor shape was devised. In this study, we present the measurement results of the oil-film pressure distribution in engine connecting rod big-end bearing and piston pin- bosses with 3 different pin-boss shapes using the newly developed thin-film pressure sensor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.929-933
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• 2003

Internal defects of thin pressure vessel used in the power plants or the chemical plants may be created and grow due to corrosion or creep fatigue to reduce the strength and cause critical failure during operation. Therefore it is very important to detect this defect at the early stage. For this purpose, non-destructive, non-contact and highly sensitive method should be considered for on-line application. In this paper, a laser shearographic interferometer is applied to inspect circular defects and notch defects existed inside of thin pressure vessel under the presence of pressure up to 3 times of atmospheric pressure. The influences of the defect shape and size as well as the internal pressure to the characteristic pattern in the shearography fringe are investigated, and the quantitative evaluation of the defect size is tried. Also the experimental results are compared with the destructive test results to show the applicability of this method to the quantitative evaluation of internal defects in the thin pressure vessel.