• Journal of the Korean Society of Physical Medicine
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• v.10 no.4
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• pp.9-14
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• 2015

PURPOSE: Low-intensity exercise with restriction of blood flow has been proposed as an alternative exercise to secure the disadvantage of a high-intensity resistance exercise. However, studies of how affects the muscle using functional exercise are lacking. Thus, the purpose of this study was to investigate knee extensor muscle strength during stair exercise of functional exercise with leg blood flow restriction. METHODS: Twenty two healthy young adults with no history of musculoskeletal or neurogical disorder were participated in this study. participant were randomized into either non-restriction group(11 subject) or restriction group (11 subject). The restriction blood cuff attached to the proximal end of the leg. Measurement of knee extensor strength was used by cybex dynamometer. Data analyzed in independent t-test and paired t-test. RESULTS: Knee extensor muscle strength was significantly different between groups. Also, there were significant differences in the strength of knee extensor within the group. CONCLUSION: This study found that stair exercise with restriction of blood flow did influence to knee extensor muscle strength. These results will also be able to promote the effect of increasing the muscle power applied to functional exercise. Henceforth, studies will be made in the intervention method that can be applied to health vulnerable person.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.382-387
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• 1999

The processes and the kinetics of the lithium intercalation into the spin coated $V_2O_5$ xerogel prepared by the sol-gel processing have been studied employing impedance analyzer. Homogeneous and quasi-isotropic thin films of the xerogel can be obtained as a result of random distribution of the $V_2O_5$ gels on the substrate by the use of the spin coating. Effective diffusion coefficient and charge transfer resistance vary more than one order of magnitude at high and low lithium composition in $V_2O_5$ xerogel, respectively.

• Analytical Science and Technology
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• v.8 no.4
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• pp.597-601
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• 1995

The transfer of chloride ion across an anion exchange membrane (AEM) was investigated by cyclic voltammetry (CV) and electrochemical impedance spectra. In CV experiment, when the size of the hole in membrane was much smaller than the distance between membrane holes, the Cl anion transfer showed steady state voltammetric behavior. Each hole in membrane can be regarded as a microelectrode and the membrane was equivalent to a microelectrode array in this condition. When the hole in membrane was large or the distance between membrane holes was small, the CV curve of the Cl anion transfer across membrane showed peak shape, which attributed to linear diffusion. In ac impedance measurement, the impedance spectrum of the membrane system was composed of two semicircles at low de bias, corresponding to the bulk characteristics of the membrane and the kinetic process of ion transfer, respectively. The bulk membrane resistance increases with increasing dc bias and only one semicircle was observed at higher dc bias. The parameters related to kinetic and membrane properties were discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.4
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• pp.41-46
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• 2005

In this paper, a new method for suppressing microwelding on the RF MEMS (Radio Frequency Microelectromechanical System) direct contact switches is introduced. Two kinds of refractory metals, tungsten and molybdenum were coated onto the contact point of the switches and the effect of the coating was examined. The changes in insertion loss and isolation at the switch were measured by using network analyzer and power loss was evaluated by power measurement. The results revealed that while tungsten and molybdenum showed higher contact resistance than gold in low input power range, they enhanced the power handling capability and reliability of the switches in high input power region.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.1
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• pp.74-81
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• 2001

The sensorless scheme for Switched Reluctance Motor(SRM) drives must have the robustness and reliability because the noise and error are sensitive. These elements make electrically noisy environments due to the proximity of high current power circuits with small signal electronic circuits when SRM drives. Also, due to the leakage inductances and finite coupling capacitances, these can cause the noise on any low voltage current and voltage measurement circuit. The position estimate error occurs because the current and voltage including the noise are sued as the inputs of sensorless algorithm. In this paper the high robustness and resistance of input noise re described. The fuzzy logic based rotor estimation algorithm and the observer model are used to reduce the tolerance of input data.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.412-413
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• 2007

We report on the electrical, optical, and structural properties of indium zinc tin oxide (IZTO) anode films grown at room temperature on glass substrate. The IZTO anode films grown by a RF magnetron sputtering were investigated as functions of RF power, working pressure, and process time in pure Ar ambient. To investigate electrical, optical and structural properties of IZTO anode films, 4-point probe, Hall measurement, UV/Vis spectrometer, Field Emission Scanning Electron Microscopy (FE-SEM), and X-ray diffraction (XRD) were performed, respectively. A sheet resistance of $13.88\;{\Omega}/{\square}$, average transmittance above 80 % in visible range were obtained from optimized IZTO anode films grown on glass substrate. These results shown the amorphous structure regardless of RF power and working pressure due to low substrate temperature.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.253-256
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• 2004

Acoustical noise at low frequency range (below 500Hz) of refrigerator result from fans which are inside of the refrigerator. In generally to evaluate and apply to refrigerator it is recommended that acoustical noise and fluidic performance of the fan were measured simultaneously. To do that twin-room type anechoic wind tunnel was needed. But constructing twin room type anechoic wind tunnel was very expensive and estimation of small refrigerator fan performance was not easy. So in this paper we composed anechoic fan tester. A successful noise and performance measurement was performed using the anechoic fan tester. Existing 22 kinds of refrigerator fan were investigated and mapped into one database. Refrigerator duct pressure resistance were measured and reflected into the fan database to find out appropriate fan. Through the application of fan database, the refrigerator became less noise compared to current one and these data shows what is the best way to reduce fan noise.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.1
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• pp.31-39
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• 2008

The development of next-generation resident registration cards, financial IC cards and administrative agency IC cards based on a smart card is currently coming out in Korea. However, the low-price IC cards without countermeasures against side channel analysis attacks are expected to be used fer cost reduction. This paper has investigated the side channel resistance of financial IC cards that are currently in use and have performed DPA attacks on the financial IC cards. We have been able to perform successful DPA attacks on these cards by using only 100 power measurement traces. From our experiment results, we have been able to extract the master key used for encryption of a count PIN number.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.1
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• pp.15-23
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• 2024

In order to avoid the high observability due to the cavity resonance or electromagnetic wave leakages from the bridge of a battleship or the cockpit of an aircraft, this paper presents a transparent conductive oxide coated structure to prevent the incoming/outgoing electromagnetic waves. Currently, most of the RCS reduction technologies were focused on radar absorbing material such as paints based on conductive or magnetic materials in the fuselage, and there is not much research on countermeasures for achieving the low observability of materials that required optical transparency in actual weapon systems. In this study, the transmission/reflection and absorption performance of the ITO coated structure according to the change of the surface resistance of the transparent conductor were analyzed. Finally, the relationship between the electromagnetic and optical characteristics was established through fabrication and measurement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.5
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• pp.307-312
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• 2018

Liquid phases in ZnO varistors cause more complex phase development and microstructure, which makes the control of electrical properties and reliability more difficult. Therefore, we have investigated 2 mol% $CaCO_3$ doped $ZnO-Co_3O_4-Cr_2O_3-La_2O_3$ (ZCCLCa) bulk ceramics as one of the compositions without liquid phase sintering additive. The results were as follows: when $CaCO_3$ is added to ZCCLCa ($644{\Omega}cm$) acting as a simple ohmic resistor, CaO does not form a secondary phase with ZnO but is mostly distributed in the grain boundary and has excellent varistor characteristics (high nonlinear coefficient ${\alpha}=78$, low leakage current of $0.06{\mu}A/cm^2$, and high insulation resistance of $1{\times}10^{11}{\Omega}cm$). The main defects $Zn_i^{{\cdot}{\cdot}}$ (AS: 0.16 eV, IS & MS: 0.20 eV) and $V_o^{\bullet}$ (AS: 0.29 eV, IS & MS: 0.37 eV) were found, and the grain boundaries had 1.1 eV with electrically single grain boundary. The resistance of each defect and grain boundary decreases exponentially with increasing the measurement temperature. However, the capacitance (0.2 nF) of the grain boundary was ~1/10 lower than that of the two defects (~3.8 nF, ~2.2 nF) and showed a tendency to decrease as the measurement temperature increased. Therefore, ZCCLCa varistors have high sintering temperature of $1,200^{\circ}C$ due to lack of liquid phase additives, but excellent varistor characteristics are exhibited, which means ZCCLCa is a good candidate for realizing chip type or disc type commercial varistor products with excellent performance.