• Journal of Mechanical Science and Technology
• /
• v.19 no.6
• /
• pp.1338-1346
• /
• 2005

Effects of thermal contact resistance between heater and susceptor, susceptor and graphite board in a MOCVD reactor on temperature distribution and film growth rate were analyzed. One-dimensional thermal resistance model considering thermal contact resistance and heat transfer area was made up at first to find the temperature drop at the surface of graphite board. This one-dimensional model predicted the temperature drop of 18K at the board surface. Temperature distribution of a reactor wall from the three-dimensional computational fluid dynamics analysis including the gap at the wafer position showed the temperature drop of 20K. Film growth rates of InP and GaAs were predicted using computational fluid dynamics technique with chemical reaction model. Temperature distribution from the three-dimensional heat transfer calculation was used as a thermal boundary condition to the film growth rate simulations. Temperature drop due to the thermal contact resistance affected to the GaAs film growth a little but not to the InP film growth.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.11a
• /
• pp.161-162
• /
• 2020

In this study, as part of securing related data, water droplets were dropped on the upper part of the wooden board for flooring in an environment such as floor heating, and the degree of absorption according to the surface temperature change was tested. The test results showed that the contact angle of the surface was low (25℃→40℃) or the droplet was absorbed into the small plate and disappeared. The contact angle of the OSB and MDF was decreased within 30 minutes, but the surface water droplet was maintained longer than the plywood. This is because the surface is coated with hydrophobicity unlike the plywood, but moisture absorption in the cross section after the second processing will not be prevented and it will lead to defect occurrence problem.

• Korean Journal of Applied Biomechanics
• /
• v.13 no.3
• /
• pp.67-79
• /
• 2003

The purpose of this study is to investigate the effective skill motion through the kinematic analysis of the Yurchenko Streched motion in new horse vaulting. The subjects in this study were 3 male gymnasts who were ranked as national athletes. After the 3D motion analysis, kinematic variables were analyzed to comparison with the difference between this study and the previous study(Yang, D. Y and Lee, C. S, 1999). As a result, the following conclusions was drawn; 1. In the board contact phase, this study showed a shorten contact time to maintain in condition highly extension of hip and hee angle than the previous study. 2. In the pre-flight phase, this study appeared more shortly flight duration time and horizontal flight displacement than the previous study. 3. In the horse contact phase, the contact duration time and horizontal displacement of COG shortened than the previous study, but appeared to the fast horizontal and vertical velocity and highly extension of shoulder an. 4. In the post-flight phase, a stable horse contact appeared to the increase of the flight duration time and the apex height during the post-flight. And it showed that these results have a stable and good landing.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.3 no.2
• /
• pp.18-24
• /
• 2010

On-board spectrophotometer has been widely used as a non-contact and non-destructive measurement system in many fields. In this study, we evaluated the effect with respect to the light of on-board spectrophotometer based on a comparison with the standard spectrophotometer and color information coordinate system. Red, yellow, green and blue color paper, which were the standard reflective color paper and Munsell color paper, were used for experiments. In order to compare between a standard spectrophotometer system and an on-board spectrophotometer system, each color paper was measured 20 times. We concluded that it is possible to develop a system regardless the effect of light if the light was supplied consistently and a calibration was performed exactly while we applied an on-board spectrophotometer to non-contact and non-destructive measurement system.

• Journal of the Semiconductor & Display Technology
• /
• v.19 no.3
• /
• pp.106-111
• /
• 2020

In this paper, we propose the non-contact gesture recognition system and algorithm using proximity-based sensors. The system uses four IR receiving photodiode embedded on a single chip and an IR LED for small area. The goal of this paper is to use the proposed algorithm to solve the problem associated with bringing the four IR receivers close to each other and to implement a gesture sensor capable of recognizing eight directional gestures from a distance of 10cm and above. The proposed system was implemented on a FPGA board using Verilog HDL with Android host board. As a result of the implementation, a 2-D swipe gesture of fingers and palms of 3cm and 15cm width was recognized, and a recognition rate of more than 97% was achieved under various conditions. The proposed system is a low-power and non-contact HMI system that recognizes a simple but accurate motion. It can be used as an auxiliary interface to use simple functions such as calls, music, and games for portable devices using batteries.

• Journal of Institute of Control, Robotics and Systems
• /
• v.5 no.6
• /
• pp.691-697
• /
• 1999

This paper describes the implementation of a high speed image processing board. This image processing board is consist of a image acquisition part and a image processing part. The image acquistion part is digitizing the image input data from CIS and save it to the dual port RAM. By putting on the dual port memory between two parts, during acquistion of image, the image processing part can be effectively processing of large-volume image data. Most of all image preprocessing part are integrated in a large-scaled FPGA. We arwe using ADSP-2181 of the Analog Device Inc., LTD. for a image processing part, and using the available all memory of DSP for the large-volume image data. Especially, using of IDMA exchanges the data with the external microprocessor or the external PC, and can watch the result of image processing and acquired image. Finally, we show that an implemented image processing board used for the simulation of image retreval by the one of the typical application.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.53 no.4
• /
• pp.337-348
• /
• 2017

The tension of warp from trawler and sea-floor contact can generate tilt and wake turbulence around otter boards. Preliminary measurements of otter board tilt and 3-D flow velocity during bottom trawl operations were taken using a vector instrument to investigate the effects of wake turbulence at the trailing edge of the otter board. Tilt data (i.e., yaw, pitch, and roll) at 1 Hz and flow data (velocities in the towing, lateral, and vertical directions) at 16 Hz were analyzed to determine their periods and amplitudes using global wavelet and peak event analyses. The mean period (${\pm}standard$ deviation) of the tilt from the peak event analysis ($5{\pm}2s$) was longer or double than that of flow velocity ($3{\pm}2s$). The two periods also had a significant linear relationship. The turbulence rate of flow was 30-50% at the trailing edge and was closely related to roll deviation. The frequency of phase difference ratios (i.e., peak time differences between tilts and flow periods) was significantly different from random occurrence in two trials, possibly due to side tidal effects. However, in the other trials, flow peaks were random, as shown by the even peak times between tilts and flows. Future studies should focus on reducing tilt variation, wake turbulence, and bottom contact to stabilize otter board motion.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.2
• /
• pp.379-385
• /
• 2017

In general, distribution board, panel board and motor control center can be installed over a wide area such as residence of group, building, schools, factories, ports, airports, water service and sewerage, substation and heavy industries that are used to supply converts the voltages extra high voltage into optimal voltage. There are electrical accidents due to rise of contact temperature, loose contact between busbar, deterioration of the contact resistance, over temperature of the busbars. In this paper, we designed and implemented the busbar joint and temperature measurement system, which can measure the joint resistance of busbar and loose connection between busbar using potentiometer and non-contact infrared sensor. The experimental results show that tightening the bolt and nut is fully engaged, resistance was decreased and maximum error range was 0.1mm. Also, the experimental result showed that the temperature at the contact area is increased from $27.3^{\circ}C$ to $69.3^{\circ}C$by the contact resistance.

• Nuclear Engineering and Technology
• /
• v.53 no.4
• /
• pp.1176-1180
• /
• 2021

The current study relates to RADAR (RAdio Detection and Ranging) application for level measurement of vitrified radioactive liquid nuclear waste. The vitrification of radioactive liquid waste is carried out in special equipment called 'Melters'. The study is directed towards the design and frequency modulation used in the level measurement of vitrified waste. More specifically, the RADAR design and frequency used for level measurement in a melter. This level measurement technique can also be used for dynamic vitrification process and can be used to measure the level variations without using any external medium/material and using only electromagnetic waves. Also, this technique is durable and accurate even under the high radioactive environment present inside the melter.

• Korean Journal of Applied Biomechanics
• /
• v.15 no.4
• /
• pp.1-11
• /
• 2005

The study were to assess technical factors between the high score group and the low score group, from the subjects of 8 male national gymnasts, and to analyze the kinematical characteristic and main technical cause on technique of Kasamatsu movement on Vault. The result of this study is this. In case of horse contact time the high score group was swifter than low score group, and there was significant difference between the high score group and the low score group(<.01). On high score group the time of taking on from horse showed shorter than that of taking off from horse, while of the low score group the time of taking on the horse was similar to that of taking off from horse on the average. And in time of pre-flight the high score group on average the was 0.16sec shorter times than the low score group, and so there was significantly difference between groups(<.05). Also It is a characteristic that the high score group was short in horse contact time and longer in post-flight. In the horizontal distance of post-flight, the high score group was 0.11m longer than the low score group and there was significantly statistic difference between groups(<.05). In the vertical height of the cog in Post-flight's phrase, the high score group was 0.15m higher than the low score group and there was significantly statistic difference between groups(.<01). The horizontal velocity and vertical velocity in the event of taking on and off Beat board and Vault weren't significantly statistic differences between two groups. In the slow-down of average horizontal velocity during keeping contact with the beat board, the high score group was larger than the low score group. And in an increased average vertical velocity during keeping contact with the beat board, the high score group was even larger than the low score group. In the projectile angle of cog in taking off the beat board, 40.2deg., the angle of low score group and 39.5deg., the angle of high score group are nearly alike. In the projectile angle of cog in taking off the beat, the high score group showed 1.6Wt larger on average than the low score group. However the average reaction force on the board and Vault wasn't almost different between two groups, showed 0.3~0.6Wt larger in the high score group.