• The Journal of Korean Physical Therapy
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• v.13 no.3
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• pp.735-749
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• 2001

The purpose of this study was to compare the flexibility and isokinetic differences between normal dancers and dancers with chronically sprained ankle. For the experiment Eversion/Inversion testing was performed by a Cybex 770 isokinetic dynamometer at the a speeds of 30$^{\circ}$ /sec and 120$^{\circ}$ /sec on each 7 subject group. The results were; 1) No differences were found between the two groups in ROM of ankle, but ROM of eversion has 2.8$^{\circ}$ higher in the injury group than the normal group. 2) Differences were found between the two groups in peak torque. average power, total work at the evertor and invertor in injury side.(30$^{\circ}$ /sec) 3) Differences were found between the two groups in peak torque at the evertor and invertor in normal side.(30$^{\circ}$ /sec) 4) Differences were found between the two groups in total work at the evertor in normal side. (30$^{\circ}$ /sec) 5) Differences were found between the two groups in peak torque, total work at the evertor and invertor in injury side. (120$^{\circ}$ /sec)

• Textile Coloration and Finishing
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• v.25 no.2
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• pp.110-117
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• 2013

The purpose of this study is to fabricate the flame retardant polyester fabric by thermal bonding with low melting component of flame retardant bicomponent filament(LMFRPC) and to describe the characteristics of thermal bonded fabrics. The fabrics were prepared with flame retardant polyester filaments(FRP) as warp and blended filaments of FRP and LMFRPC as weft. The LMFRPC have a sheath and a core wherein the core comprises a flame retardant polyester and the sheath comprises a thermoplastic polyester of low-melting point. In this study, we investigated the physical properties, melting behavior of filament, the effect of the component of FRP and LMFRPC on the thermal bonding, mechanical properties. Melting peak of LMFRPC showed the double melting peak. The thermal bonding of the fabric formed at lower melting peak temperature of bicomponent filament of LMFRPC. The optimum thermal bonding conditions for fabrics was applied at about $170^{\circ}C$ for 60 seconds by pin tenter. On the other hand, the tensile strength, elongation, and LOI of the fabric increased with an increasing component of FRP of weft.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.1
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• pp.22-28
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• 2009

This paper presents a fast received signal strength indicator (RSSI) circuit for wireless communication application. The proposed circuit is developed using power detectors and an analog-to-digital converter to achieve a fast settling time. The power detector is consisted of a novel logarithmic variable gain amplifier (VGA), a peak detector, and a comparator in a closed loop. The VGA achieved a wide logarithmic gain range in a closed loop form for stable operation. For the peak detector, a fast settling time and small ripple are obtained using the orthogonal characteristics of quadrature signals. In $0.18-{\mu}m$ CMOS process, the RSSI value settles down in $20{\mu}s$ with power consumption of 20 mW, and the maximum ripple of the RSSI is 30 mV. The proposed RSSI circuit is fabricated with a personal handy-phone system transceiver. The active area is $0.8{\times}0.2\;mm^2$.

• Bulletin of the Korean Chemical Society
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• v.26 no.1
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• pp.136-138
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• 2005

High-performance frontal analysis (HPFA) was used for the determination of the binding constant of Sibuprofen to human serum albumin (HSA). This experiment was based on an Inertsil 100 Diol 5 column and sodium phosphate buffer (pH 7.4 and ionic strength of 0.17) as the mobile phase. The mixture of S-ibuprofen and HSA (70 $\mu$M) solution were directly injected into the HPFA column. An injection volume of 200 $\mu$L and a “estricted injection”method were applied to ensure the drug to be eluted as a zonal peak with a plateau. The unbound drug concentration was calculated from the peak height of the zonal peak. Scatchard analysis was used for evaluation of the binding constant (K) and binding affinity (nK) of S-ibuprofen to HSA, and the results were K = 2.833 ${\times}$ 10$^4$ [L mol$^{-1}$], nK = 4.935 ${\times}$ 10$^4$ [L mol$^{-1}$], respectively.

• Journal of Sensor Science and Technology
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• v.22 no.6
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• pp.379-386
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• 2013

The influences of the load resistance $R_L$ on the magnetoelectric (ME) characteristics of $NiZnFe_2O_4+PZT$ composite were investigated in the non-resonance frequency range. The ME coefficient peak increases with increasing $R_L$, but the frequency indicating the ME coefficient peak decreases with increasing $R_L$. The maximum output power peak is approximately $9.3{\times}10^{-10}mW/Oe$ near $R_L=3.3M{\Omega}$ at f=280 Hz, and the ME coefficient seems to be saturated at $R_L>20M{\Omega}$. This frequency shift effect of $R_L$ shows that the frequency range for an ME sensor application can be modulated with the appropriate value of $R_L$. The ME output voltage has a good linear response to the ac field Hac and shows fair stability over a range of temperatures. The measured non-linearity of this sample is approximately 0.8%. This sample will allow for a low-strength magnetic ac-field sensor. The result from this sample will serve as basic data for a signal-processing circuit system.

• Structural Engineering and Mechanics
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• v.91 no.5
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• pp.427-441
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• 2024

Large-scale cantilever reinforced concrete (RC) columns with footing/stub were examined to determine their seismic response under a quasi-static increasing-magnitude cyclic lateral loading. Three-dimensional (3D) numerical models of RC columns with ductile and non-ductile reinforcement arrangements were developed in a Finite Element (FE) software, i.e., ABAQUS, to corroborate them with the experimental study conducted by the author. Both simulated models were validated with the experimental results in all respects, and the theoretical axial capacity of columns under concentric axial load (P₀) was calculated. Subsequently, a detailed parametric study was conducted by adopting the force and reinforcement variables. These variables include axial compression ratios (ACR) varying from 0.35P₀ to 0.7P₀ and the amount of lateral reinforcements taken as 0.33% and 1.31% representing the non-ductile and ductile columns, respectively. This research outcome conclusively quantifies the combined effect of ACR levels and lateral reinforcement spacing on the flexural response and ductility characteristics of RC columns. The comparative analysis reveals that increased ACR levels resulted in a severe reduction in strength, deformability and ductility characteristics of both ductile and non-ductile columns. Structural response of ductile columns at higher ACR levels was comparable to the non-ductile columns, nullifying the beneficial effects of ductile design provisions. Higher ACR levels caused decline in pre-peak and post-peak response trajectories, leading to an earlier attainment of peak response at lower drift levels.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1864-1866
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• 1999

The magnetic nondestructive test can be applied to evaluate the magnetic material characteristics and the fracture properties through the internal defects of SA-508 used in the pressure vessels of the nuclear power plants as the direct and accurate in-situ testing methods. The fracture toughness, yield strength and the stress distribution around the defects in the surface and sub-surface of magnetic materials can be directly estimated by Bark-hausen noise(BN) methods as NDT. The testing process of SA-508 by Barkhausen noise method was advanced by controlling the austenizing peak temperature and the time of maintenance at a constant austenizing peak temperature, therefore causing the variation of fracture toughness. Through above process. we can evaluate the variations of effective grain size and the correlation of effective grain size and FATT at each situation. And the stress distribution around the defects can be quantified nondestructively through Barkhausen method.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.393-400
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• 2003

지오멤브레인(geomembrane)과 다른 토목섬유, 즉 지오텍스타일 또는 GCL, 사이의 interface 전단거동을 특성화하는 strain-softening 모델을 개발하였다. 본 연구에 제안된 모델은 일차적으로 smooth 지오멤브레인과 textured 지오멤브레인을 대상으로 실시한 직접전단 시험결과를 대상으로 구축되었다. 시험을 통해 측정된 변위-전단응력의 관계는 strain-softening 현상를 고려하기 위해서 최대점이 발생하는 위치를 기준으로, pre-peak과 post-peak 영역으로 나누어 분석을 실시하였다. 실험결과를 토대로 구축된 모델식은 원 자료와의 비교를 통해 본 모델의 유효성을 검증하였다. 비교 결과 높은 연직 응력에서 약간의 차이를 보이긴 하지만, 대체적으로 실험 결과와 구축된 모델을 이용한 역계산의 값이 좋은 일치를 보임을 확인할 수 있었다. 특별히 연직응력이 낮은 단계에서는 높은 일치를 보였는데, 이를 통해 제안된 식이 매립지의 최종 cover와 같이 상재 연직하중이 작은 경우에 지오멤브레인이 포함된 interface의 전단 거동에 대한 합리적인 구성 방정식이 될 수 있음을 확인할 수 있었다.

• Bulletin of the Korean Chemical Society
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• v.26 no.5
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• pp.735-739
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• 2005

Presented is a voltammetric study of co-adsorption of irreversibly adsorbing Sb and Te on Pt(111). When a layer of Sb and Te was formed via simultaneous adsorption, the reduction peak of Te was observed at 0.30 V in the initial cathodic scan. In contrast, sequential adsorption of Sb followed by Te adsorption led to a Te reduction peak at 0.50 V in the initial scan. As the voltammetric scan was continued, in addition, the voltammogram of the simultaneously co-adsorbed layer changed, while that of the sequentially co-adsorbed layer did not. These observations are discussed in terms of formation of a homogeneously mixed layer and a layer consisting of heterogeneously separated domains of Sb and Te. Also, the difference in the adsorption strength of Sb and Te was observed.

• Computers and Concrete
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• v.20 no.2
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• pp.129-143
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• 2017

Seismic design of reinforced concrete (RC) structures requires a certain minimum level of flexural ductility. For example, Eurocode EN1998-1 directly specifies a minimum flexural ductility for RC beams, while Chinese code GB50011 limits the equivalent rectangular stress block depth ratio at peak resisting moment to achieve a certain nominal minimum flexural ductility indirectly. Although confinement is effective in improving the ductility of RC beams, most design codes do not provide any guidelines due to the lack of a suitable theory. In this study, the confinement for desirable flexural ductility performance of both normal- and high-strength concrete beams is evaluated based on a rigorous full-range moment-curvature analysis. An effective strategy is proposed for flexural ductility design of RC beams taking into account confinement. The key parameters considered include the maximum difference of tension and compression reinforcement ratios, and maximum neutral axis depth ratio at peak resisting moment. Empirical formulae and tables are then developed to provide guidelines accordingly.