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김진환,김형준,유복상 충북대학교 농업과학기술연구소 2001 農業科學硏究 Vol.18 No.-
Labor saving, simple and fast instration of hawse band is necessary for house management. Therefore, this study was conducted to evaluate the cord materials(rice transplsnting string, pack sack band and drip irrigation nozzle and house band) and installation methods(string exchange, both side throwing, ball throwing and and both side throwing) of house band. Both side throwing + Ball throwing) of house band. Both side throwing of drip irrigation nozzle appeared to be the fatest method for house band installation. Attachment of tennis ball of 160∼ 180g at the both end of drip irrigation nozzle enabled fast band installation in both side throwing and only one man is able to install the house band
Hyoung Jin Lee,Bok Jin Lee,In-Seuck Jeung,Seoung-Lyoung Kim,Insun Kim 한국항공우주학회 2010 International Journal of Aeronautical and Space Sc Vol.11 No.3
Through experimental investigations utilizing hypersonic shock tunnel-coaxial thermocouples as well as blow down hypersonic wind tunnel-temperature sensitive paints, the heat flux and the temperature over a protuberance were measured and analyzed. The experimental data were subsequently compared to heat flux data that was obtained by using blow down hypersonic wind tunnel and heat flux gauges. According to the comparison, both sets of data illustrated correlation with one another. The measured heat flux was large when the height of the protuberance was large. Experimental results show that heat flux measurements taken at higher locations were greater than those taken at lower locations. For high protuberances, a severe jump in the heat flux was observed, ranging in values within 0.6-0.7 of the height of the protuberances. However, when the protuberance was sufficiently short, a rise in the heat flux was rarely observed as the protuberance was totally submerged under the separation region.
Lee, Hyoung-Jin,Lee, Bok-Jin,Jeung, In-Seuck,Kim, Seoung-Lyoung,Kim, In-Sun The Korean Society for Aeronautical and Space Scie 2010 International Journal of Aeronautical and Space Sc Vol.11 No.3
Through experimental investigations utilizing hypersonic shock tunnel-coaxial thermocouples as well as blow down hypersonic wind tunnel-temperature sensitive paints, the heat flux and the temperature over a protuberance were measured and analyzed. The experimental data were subsequently compared to heat flux data that was obtained by using blow down hypersonic wind tunnel and heat flux gauges. According to the comparison, both sets of data illustrated correlation with one another. The measured heat flux was large when the height of the protuberance was large. Experimental results show that heat flux measurements taken at higher locations were greater than those taken at lower locations. For high protuberances, a severe jump in the heat flux was observed, ranging in values within 0.6-0.7 of the height of the protuberances. However, when the protuberance was sufficiently short, a rise in the heat flux was rarely observed as the protuberance was totally submerged under the separation region.
Self-Ignition of Hydrogen in a Pipe by Rupture of Pressure Boundaries
Bok Jik Lee(이복직),Hyoung Jin Lee(이형진),In-Seuck Jeung(정인석) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.39
Direct numerical simulations with detailed reaction kinetics are conducted to investigate the mechanism of spontaneous ignition of hydrogen within a certain length of downstream pipe released by the failure of pressure boundaries of various geometric assumption to see their effect on the formation of flammable mixture volumes and the development of ignition sources. Numerical simulations are conducted using the unsteady, compressible two-dimensional axisymmetric Navier-Stokes equations for a chemically reactive multi-species mixture of ideal gases. And total number of cells is used about 4 millions. Only local ignition is developed in limited area such as boundary layer and the mixing of hydrogen and air is weak at the planar pressure boundary conditions, whereas the flame fronts at the contact region of hydrogen and air are developed at the pressure boundaries of the spherical shape. It is found that the initial formation of multi-dimensional shock wave and sufficient length of downstream pipe which allows the sufficient time of mixing by shock interactions are necessary for the spontaneous ignition kernel that is developed within the pipe length.
( Bok Hee Jin ),( Jae Hyoung Lee ),( Onishi Hideaki ) 대한임상검사과학회 2000 대한임상검사과학회지(KJCLS) Vol.32 No.3
The estimation of electrically induced muscle contraction forces is important for thereduce of muscle fatigue during neuromuscular electrical stimulation. The electromyographic signal has potential as an indicator of muscle fatigue. The purpose of this study was toassess muscle fatigue using electromyographic spectral analysis with median power frequency and mean frequency during muscle contraction. Twelve healthy male subjects were divided into the neuromuscular electrical stimulation and control group. Fatigue was induced by having neuromuscular electrical stimulation subjects perform 50 second isometric contractions followed by 10 second rests for 10 minutes using Russian current electrical stimulation with 80 Hz. All subjects lies comfortably on a table to perform sustained contraction in the vastus medialis muscle for 30 seconds with maximal voluntary isometric contraction. The electromyogram was recorded using MP 100 System from vastus medialis muscle in both neuromuscular electrical stimulation and control group. The time serial data of the electromyographic signals were transformed into frequency serial data by Fast Fourier Transformation. The frequency changes ratio of median frequency was significantly lower in neuromuscular electrical stimulation group compared with control group (p<0.001) and the frequency changes ratio of mean frequency was significantly lesser in neuromuscular electrical stimulation group compared with control group (p<0.05). These results showed that the median frequency and mean frequency were declined by muscle fatigue. These results suggest that in neuromuscular electrical stimulation there is a trend for more fatigue to occur than in control group. This would seem to suggest that the analysis of median frequency and mean frequency of surface electromyographic spectra can use for indicator of muscle fatigue. Also, in treatment programs for muscle strengthen using neuromuscular electrical stimulation, some parameters such as on-off ratio, frequency should be considered.
A Study of Hygrothermal Behavior of ACF Flip Chip Packages With Moiré Interferometry
Jin-Hyoung Park,Kyung-Woon Jang,Kyung-Wook Paik,Soon-Bok Lee IEEE 2010 IEEE transactions on components and packaging tech Vol.33 No.1
<P>A primary factor of anisotropic conductive film (ACF) package failure is delamination between the chip and the adhesive at the edge of the chip. This delamination is mainly affected by the thermal shear strain at the edge of the chip. This shear strain was measured on various electronic ACF package specimens by micro-Moire interferometry with a phase shifting method. In order to find the effect of moisture, the reliability performance of an adhesive flip-chip in the moisture environment was investigated. The failure modes were found to be interfacial delamination and bump/pad opening which may eventually lead to total loss of electrical contact. Different geometric size specimens in terms of interconnections were discussed in the context of the significance of mismatch in coefficient of moisture expansion (CME) between the adhesive and other components in the package, which induces hygroscopic swelling stress. The effect of moisture diffusion in the package and the CME mismatch were also evaluated by using the Moire interferometry. From Moire measurement results, we could also obtain the stress intensity factor <I>K</I>. Through an analysis of deformations induced by thermal and moisture environments, a damage model for an adhesive flip-chip package is proposed.</P>
동축열전대 및 TSP를 이용한 극초음속 유동 내 돌출물 주위 공력가열 계측
이형진(Hyoung Jin Lee),이복직(Bok Jik Lee),정인석(In-Seuck Jeung),김성룡(Seong-Lyong Kim),김인선(Insun Kim) 한국항공우주학회 2009 韓國航空宇宙學會誌 Vol.37 No.10
임펄스식 극초음속 충격파 풍동과 동축열전대, 불어내기식 극초음속 풍동과 온도감응페인트(TSP)를 이용하여 돌출물 전면 및 주위에서의 온도 및 열유속 계측 실험을 수행하였다. 측정된 실험 결과를 기 수행된 불어내기식 풍동과 열유속 게이지를 이용한 열유속 측정 결과와 비교하였다. 각각의 세 가지 기법의 결과가 서로 잘 일치함을 확인하였으며, 실험 결과로부터 돌출물 전면에서의 열전달 특성을 보다 명확하게 관찰할 수 있었다. 측정된 열유속 데이터로부터 공력가열 현상은 돌출물 전면 상부에서 크게 발생하며 돌출물의 크기가 작을수록 매우 미비해짐을 관찰할 수 있다. 돌출물의 크기가 큰 경우, 돌출물 높이 0.6~0.7지점부터 열유속이 크게 증가한 반면, 돌출물의 높이가 충분히 작은 경우는 돌출물 자체가 전방의 박리 영역에 완전히 잠기면서 열유속이 크게 증가하는 지점이 관찰되지 않았다. Experiments were conducted to measure the heat flux and temperature over a protuberance, using an impulse hypersonic shock tunnel-coaxial thermocouples and a blowdown hypersonic wind tunnel-temperature sensitive paints(TSP). Experimental data were compared with the heat flux data using a blowdown hypersonic wind tunnel-heat flux gauges and it was confirmed data sets agreed well. The measured heat flux is large when the height of the protuberance is large. Also, the heat flux measurements at the upper positions are larger than at the lower positions. For high protuberances, a severe jump in the heat flux is observed, from about 0.6~0.7 of the height of the protuberances. However, when the protuberance is sufficiently short, a rise in the heat flux is rarely observed as the protuberance is submerged totally under the separation region.