• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.292-295
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• 2005

본 연구는 지하유류저장공동 굴착 시 비교적 정밀하게 해석된 단열체계 및 수리인자를 토대로 투수성구조영역과 수리암반영역으로 세분화하여 연구지역의 불규칙하고 복잡한 지하수유동체계를 해석해 보고자 하였다. FZ-2 구조대와 인접한 수리암반영역 Domain-A와 B는 Domain-C와 D에 비해 수평수벽공의 초기압이 최대 약 $15kg/cm^2$정도 높으며, 상 하부의 수리적 연결성이 양호하여 지하공동굴착 시 상 하부의 수위차가 크지 않고 지하수 함양량은 약 $35{\sim}50mm/year$의 범위를 보인다. 또한 공동굴착 시 투수성 단열과의 교차에 의한 수위강하에 민감한 반응을 보이며 상 하부의 수위강하양상이 유사한 특성을 나타낸다. 반면, FZ-1 구조대와 인접한 Domain-C와 D는 지하공동 부근의 수리전도도가 각각 $7{\times}10^{-10},\;2{\times}10^{-9}m/sec$로 Domain-A와 B에 비해 최대 약 6배정도 낮고, 상 하부의 수리적 연결성이 양호하지 않기 때문에 공동굴착 전 이중수위측정시설 설치 시 계측된 상 하부의 수위차는 최대 약 120 m로 매우 크다. 그리고 상부의 지하수는 하부의 낮은 수리전도도로 인하여 수직방향보다 수평방향으로의 유동이 우세하며 공동굴착 시 수위변화는 크지 않고 함양량은 $10{\sim}15mm/year$의 범위를 나타낸다.

• Korean Journal of Acupuncture
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• v.20 no.3
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• pp.9-27
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• 2003

Objectives : The aim of this study was to examine the effects of electro-acupuncture(EA) at the SP6(Sameumgyo)-GB39(Hyeonjong) on normal human EEG using power spectral analysis. Methods : EEG power spectrum exhibit site-specific and state-related differences in specific frequency bands. In this study, power spectrum was used as a measure of complexity(LAXTHA Co., KOREA). 30 channel EEG study was carried out in 20 subjects $(20\;males;\;age=21.4{\pm}0.5\;years)$. Results : In $\alpha$(alpha) band, the power values at F4 channels(p<0.05) during the SP6-GB39 acupoints treatment was significantly increased. But, the power values at Fz channel during the non-acupoint treatment was significantly decreased . In $\beta$(beta) band, the power values at Fz, FTC1, T3 channels(p<0.05) was significantly increased during the SP6-GB39 acupoints treatment. In $\delta$(delta) band, the power values at F4, C3, Cz, CP1, Pz channels(p<0.05) during SP6-GB39 acupoints treatment were significantly decreased.

• Journal of Welding and Joining
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• v.32 no.2
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• pp.14-17
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• 2014

Ferritic stainless steels are widely used in the construction industry and in exhaust manifolds due to their low cost and relatively superior stress corrosion cracking resistance and pitting corrosion resistance compared to austenite stainless steels. Ferritic stainless steels are currently welded by various welding process including gas tungsten arc welding (GTAW), electron resistance welding (ERW) and laser beam welding. However, when these stainless steels are welded by fusion welding, some problems occur in the fusion zone (FZ) and heat affected zone (HAZ). First, the ductility of the weld is reduced due to the grain growth in the FZ and HAZ. Second, as its HAZ is frequently sensitized during welding, corrosion resistance deteriorates in this region due to the Cr depletion zone. To prevent these problems, it is recommended that ferritic stainless steels be welded with a low heat input. In this study, recent researches in the view of friction stir welded ferritic stainless steels are briefly reviewed.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.1
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• pp.31-39
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• 2016

This paper describes the design of an ankle rehabilitation robot for the force measurement of a severe stroke patient staying in a bed ward. The developed ankle rehabilitation robot was attached to a three-axis force/torque sensor that could detect force Fx, Fz, and torque Tz and measure the ankle rotation force (Fx) exerted on the ankle and the signal force Fz and torque Tz to be used as a safety device. The robot was designed and manufactured for bedridden stroke patients, and the robot program was manufactured to perform the flexibility rehabilitation exercise for ankle bending and to measure the ankle force to judge the degree of rehabilitation. According to the result of the characteristics test of the developed rehabilitation robot, it was safely operated while the ankle-bending flexibility rehabilitation exercise and the emergency situation were performed. Therefore, it is thought that the developed rehabilitation robot can be used for severe stroke patients.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.2 no.2
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• pp.77-82
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• 1992

When a crystal is grown by FZ process, the melt zone is located at between the solid of upper and lower side and is kept by the solid-liquid interface tension. On the surface of the melt zone, a surface tension gradient is occured by the difference of temperature and solute concentration, it is the driving force of marangoni flow. The crystal even in the steady state growth can become imperfect for the dislocation distribution and the solute concentration in the peripheral region of the crystal are higher than those in the inner part and the probability of the formation of the defects such as voids, bubble penetration, secondary phase creation and crack is high near the solid-liquid interface. This is because the solid -liquid interface becomes irregular because of the local variation of temperature in that region due to marangoni convection.

• Korean Journal of Crystallography
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• v.13 no.1
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• pp.41-47
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• 2002

La/sub 1-x/Ca/sub x/MnO₃ manganese oxide were grown using the floating zone image furnace with halogen lamps as heat source. The growth condition was 4∼6 mm/hr growth rate in air atmosphere, 45∼50 rpm and 20∼25 rpm of rotation rate of feedrod and growing crystal, respectively. Characterization analyses of the crystal were carried out using XRD, SEM, and EPMA. Orientation of crystal was determined using EBSD. The electromagnetic properties were measured with Quantum Design PPMS by 4 point probe method and resulted MR value of 462% at 215 K.

• Journal of Sensor Science and Technology
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• v.24 no.2
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• pp.137-143
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• 2015

This paper describes the design of a two-axis force sensor with two step plate beams for measuring forces in an upper-limb rehabilitation robot. The two-axis force sensor is composed of a Fz force sensor and a Ty torque sensor. The Fz force sensor measures the force applied to a patient's arm pushed by a rehabilitation robot and the force of patient's arm. The Ty torque sensor measures the torque generated by a patient's arm motion in an emergency. The structure of sensor is composed of a force transmitting block, two step plate beams and two fixture blocks. The two-axis force sensor was designed using FEM (Finite Element Method), and manufactured using strain-gages. The characteristics test of the two-axis force sensor was carried out. as a test results, the interference error of the two-axis force sensor was less than 1.24%, the repeatability error of each sensor was less than 0.03%, and the non-linearity was less than 0.02%.

• 한국체육학회지인문사회과학편
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• v.54 no.5
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• pp.829-840
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• 2015

The purpose of this study was to investigated into the kinematics and ground reaction force for gait on induced stereoacuity in normal subjects with normal sight. Eighteen subjects who passed the stereoacuity testing were participated in the experiment(age: 22.1±2.7 years, height: 176.8±4.4 cm, weight: 67.6±5.8 kg). The study method adopted 3D analysis with six cameras and ground reaction force with two force-plates. The results were as follows; In gait velocity, obstacle crossing gait was slower than flat gait. In angular displacement of hip joint, mostly obstacle crossing gait was more flexed than flat gait. In angular displacement of knee joint, obstacle crossing gait was more flexed than flat gait, and stereoacuity reduction gait in TO and FC2 were more flexed than normal vision gait. In angular displacement of ankle joint, obstacle crossing gait in FC2 was more flexed than flat gait. In trunk tilt, obstacle crossing gait in MSt, TO and MSw were more extended than flat gait. In GRF, there was no significant in Fx, obstacle crossing gait in right and left foot were bigger propulsion force than flat gait, obstacle crossing gait in right and left foot were bigger braking force than normal vision gait in Fy, and obstacle crossing gait in right and left foot were bigger than flat gait in peak F1 and peak F2 of Fz, and stereoacuity reduction gait in right foot was lower than normal vision gait in valley force of Fz.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.10a
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• pp.111-115
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• 1997

Iron-doped LiNbO$_3$ crystals were grown by floating zone(FZ) method with different [Li]/[Nb] ratio in order to investigate doping effects of transition metal impurity in LiNbO$_3$ crystal. The grown crystals were analyized edge in UV/VIS/IR spectrometry and EPMA(electron probe micro-analysis). The absorption edge in UV-VIS region and OH-absorption peak in IR region were investigated. The change of Fe concentration along the solidification direction was also investigated

• Journal of the Korean Ceramic Society
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• v.27 no.8
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• pp.1050-1054
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• 1990

Rutile(TiO2) single crystals were grown by FZ method. Feed rod was sintered in the longitudinal tube-shaped furnace at 135$0^{\circ}C$ and optimum growth condition was growth rate 5-8mm/hr, rotation rate 30-40rpm. When crystal was growing, atomosphere was oxidized condition, and grown single crystal was annealed at 110$0^{\circ}C$. The rutile single crystals were oriented to [001] direction and color change of single crystals were related to atmosphere, and difference of electric conductivity and resistance was due to the fact above.