• 한국자동차공학회논문집
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• 제8권6호
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• pp.130-141
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• 2000

The virbration characteristics of a passenger car steering column are studied by using a modal test and a finite element (FE) analysis. To verify the FE model and the results, an experiment using the impact exciting method is performed. Two types of the steering column in this study are considered as follows; (ⅰ) the non-tilt type steering column and (ⅱ) the upper-tilt type steering column. The experimental results are compared with those o the FE analysis, and it ti shown that the results agree with each other. The effects of various design parameters such as the bracket thickness, the column diameter on the natural frequencies are also investigated by FE analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.912-918
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• 2004

Main vibration problems of a transaxle type forklift truck are caused by the resonance of engine excitation force and natural mode shade of major components such as engine-mount system, mast, and main frame. But, it is well known that the reduction of vibration is very difficult because of the limitation of structural modifications. In this paper, the vibration characteristics of engine-mast system including engine mount were firstly identified by the experimental and simplified numerical methods. And also, the free and forced vibration characteristics of a whole forklift truck were surveyed with modal test and ODS(operation deflection shape) measurement. Based on these results, the reliable finite element model was developed. Finally, various countermeasures were considered and applied to a real forklift truck and then its effects were confirmed.

• Journal of Welding and Joining
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• 제12권4호
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• pp.151-161
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• 1994

FCAW has wide application in ship fabrication, maintenance and field erection. It has many advantages over SMAW.SAW and GMAW process. In many applications, the FCAW provides highquality weld metal. This method can reduce weld defects especially porosity and spatter. But the fatigue characteristics of those deposited metal have been rarely investigated. The purpose of this study is to investigate the cyclic stress-strain behavior and fatigue tests by the constant strain control were carried out on the rounded smooth specimen with deposited metal using the metal type flux cored wire. As the results of this study for the deposited metal welded by the metal type flux cored wire, the hardening or softening characteristics under cyclic load were investigated and cyclic stress-strain curve, strain-fatigue life curve, stress-strain function and fatigue life relation which are useful to estimate the fatigue life under the stress concentration condition were obtained.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.364-369
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• 1987

It has recently shown that a solenoid valve can be utilized in a hydraulic position-control system by discontinuous control methods. The objective of this study is to investigate the effects of solenoid valves on the response characteristics of a hydraulic position-control system by applying two kinds of discontinued control methods i.e., Simple On-Off (SOF) and Pusating On-Off(POF) controls. Three types of solenoid valves i.e. low-frequency, closed-center type (LF/C), high-frequency, closed-center type (HF/C), low-frequency, tandem-center type(LF/T) were used in this study. Effects of loading conditions and control parameters on the response characteristics were experimentally examined and compared each other. Pressure transients within the actuator were also studied.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2008년도 춘계학술발표대회 논문집
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• pp.315-318
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• 2008

The purpose of this study is to examine residential cultural attributes by analysing typological and living characteristics while focusing on various types of houses located in Gyeongju city, based on the historical and cultural background of the city. In this study, it is important to suggest methods for planning residential construction which satisfies requirements of Gyeongju citizens for living environment and considers its cultural and historical contexts. This study was performed using housing type-related questionnaires with 203 residents to find out their current living types, as well as their preferable living types in the future, during the period from the 16th to 18th day of August 2007. Analysis was performed using the SPSS 14, a statistical program, and statistically significant results were drawn from the analysis.

• 한국전기전자재료학회논문지
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• 제22권5호
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• pp.405-410
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• 2009

The conventional ultrasonic nozzle produces a mist by applying an ultrasonic vibration into a non-flowering liquid. In this paper, we first present a novel designed nozzle type sprayer that is able to apply an ultrasonic vibration directly to the moving liquid and generate a mist instantly. For the novel nozzle, a ring-type actuator of the novel nozzle was designed and built using the PZW-PMN-PZT ceramics. This paper will describe a variety of physical, mechanical, and electrical characteristics of the ultrasonic nozzle. The characteristics of the mist particles was also measured as the amount of the outflow liquid was varied.

• 한국전기전자재료학회논문지
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• 제22권1호
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• pp.93-97
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• 2009

We analyzed voltage characteristics of toner particle type display according to particle layers and cell gap between two electrodes and ascertained the aging effects by measuring the response time of particles with and without aging process. The threshold/driving/breakdown voltage is proportional to layers of toner particles and cell gap and the response time at driving voltage is faster than that of threshold and breakdown voltage because of different q/m of color and black particles. The analysis of response time is a method of estimation of optical characteristics, driving voltage and particle lumping and these results are promoted by aging process. We use the laser and photodiode to measure response time and optical properties. It has not been studied and reported to analyze the relationship of response time, threshold/driving/breakdown voltage, lumping phenomena, cell gap, and aging process for toner particle type display.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.704-706
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• 1993

This paper, introduces a Current-fed type High-Frequency Inverter with self turning devices. By replacing Thyrisors used for power source of heat treatment with high speed switching element, MOSFET in current type Inverter, the proposed Inverter makes high speed performance with several 100kHz. This paper also depicts some operating principles of the proposed circuits and general operating characteristics. Steady state solution on state variables in analysis of the proposed circuit is described generally by using normalized parameter and its characteristics depending on separate ratio(n) is also shown.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.633-635
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• 2004

The current limiting characteristics of the flux-lock type superconducting fault current limiters(SFCLs) were investigated. The flux-lock type SFCL consists of a flux-lock reactor and high-T_c superconducting (HTSC) element. In this SFCL the initial limiting current level can be controlled by adjusting the inductances of two coils. In this paper, the operational characteristics of the flux-lock type SPCL were analyzed and the current Limiting characteristics of it were investigated through the experiments.

• 전기학회논문지
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• 제61권6호
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• pp.817-820
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• 2012

We studied p-type capacitance characteristics of ZnO thin-film transistors (TFT's), grown by metal organic chemical vapor deposition (MOCVD). We compared two ZnO TFT's: one grown at $450^{\circ}C$ and the other grown at $350^{\circ}C$. ZnO grown at $450^{\circ}C$ showed smooth capacitance profile with electron density of $1.5{\times}10^{20}cm^{-3}$. In contrast, ZnO grown at $350^{\circ}C$ showed a capacitance jump when gate voltage was changed to negative voltages. Current-voltage characteristics measured in the two samples did not show much difference. We explain that the capacitance jump is related to p-type ZnO layer formed at the $SiO_2$ interface. Current-voltage and capacitance-voltage data support that p-type characteristics are observed only when background electron density is very low.