• 한국재료학회지
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• 제15권7호
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• pp.465-472
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• 2005

Preparation of copper film on PET substrate was carried out by cyclic operation of RF-magnetron­sputtering under continuous operation of ECR-CVD. The purpose of this study is aimed to an increase in deposition rate with keeping excellent adhesion between copper film and PET. In order to optimize the sputtering time under continuous ECR-CVD, cyclic operation concept is employed. By changing parameters of cyclic operation such as split of e and cycle time of A, the characteristics and thickness of the deposited copper film are controlled. As $\theta$ value increase, film thickness could confirm to increase and its surface resistivity value decreases. The highest adhesive strength appears at $\theta=0.33$ and cycle time of 30 min. The uniformity of copper film shows $5\%$ in our experimental range.

• Journal of Mechanical Science and Technology
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• 제15권1호
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• pp.81-87
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• 2001

Cyclic variability limits the range of operating conditions of spark ignition engines, especially under lean and highly diluted operation conditions. The cyclic combustion variations can be characterized by pressure parameters, combustion related parameters, and flame-front related parameters. The coefficient of variation (COV) in indicated mean effective pressure (IMEP) defines the cyclic variability in indicated work per cycle.

• Nuclear Engineering and Technology
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• 제51권4호
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• pp.1109-1116
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• 2019

It is essential to predict the radioactivity distribution around the reactor cooling system (RCS) during obligatory cyclic operation of AP-1000. A home-developed program CPA-AP1000 is upgraded to predict the response of activated corrosion products (ACPs) in the RCS. The program is written in MATLAB and it uses state of the art MCNP as a subroutine for flux calculations. A pair of cyclic power profiles were superimposed after initial full power operation. The effect of cyclic operation is noticed to be more prominent for in-core surfaces, followed by the primary coolant and out-of-core structures. The results have shown that specific activity trends of $^{56}Mn$ and $^{24}Na$ promptly follow the power variations, whereas, $^{59}Fe$, $^{58}Co$, $^{99}Mo$ and $^{60}Co$ exhibit a sluggish power-following response. The investigations pointed out that promptly power-following response of ACPs in the coolant is vital as an instant radioactivity source during leakage incidents. However, the ACPs with delayed power-following response in the out-of-core components are perceived to cause a long-term activity. The present results are found in good agreement with those for a reference PWR. The results are useful for source term monitoring and optimization of work procedures for an innovative reactor design.

• Asian-Australasian Journal of Animal Sciences
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• 제1권3호
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• pp.143-147
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• 1988

In order to investigate the mechanism of regulation of progesterone production, quail were hypophysectomized at various times during the ovulation cycle, and granulose cells were isolated from follicles 4 hr after the operation. They were incubated in vitro at $40^{\circ}C$ with or without LH or dibutyryl cyclic AMP, and the amounts of progesterone produced during 3 hr of incubation were measured by radioimmunoassay. Hypophysectomy at 8 hr or 20 hr before the predicted time of ovulation caused a reduced responsiveness of F1 granulosa cells to exogenous LH or dibutyrul cyclic AMP. Although hypophysectomy at 24 hr before ovulation caused a slight reduction of responsiveness of F1 granulosa cells, the reduction of the progesterone production during the incubation without any stimuli was prominent by the sham operation. These results suggest that the presence of pituitary gland influences the ability of the granulose cells to produce progesterone in response to LH or dibutyryl cyclic AMP.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년도 춘계 학술대회 개요집
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• pp.45-47
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• 2006

The rotating components in the hot sections of land-based gas turbine are exposed to severe environments during several tens thousand operation hours at above $1100^{\circ}C$ operation temperature. To protect such components from high temperature oxidation, an intermediate bond coat is applied, typical of a MCrAlY-type metal alloy. This study is concerned with the thermal cyclic behavior of thermal barrier coatings. The MCrAlY bond coatings are deposited by HVOF (High Velocity Oxygen Fuel) method on a nickel-based superalloy (GTD-111). Thermal cyclic tests at $1100^{\circ}C$ in ambient air for various periods of time were used to evaluate the thermal cyclic resistance of the TBC coating. The microstructure and morphology of as-sprayed and of thermal cycled coatings were characterized by scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1578-1581
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• 2009

This work describes a power and area efficient switched-capacitor cyclic DAC for mobile display drivers. The proposed DAC can be simply implemented with one opamp two capacitors and several switches. Furthermore, the op-amp input referred offset is attenuated at the DAC output without additional offset cancellation circuitry. The operation of the cyclic DAC is verified through circuit level simulations.

• 대한기계학회논문집B
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• 제24권5호
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• pp.709-717
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• 2000

Cyclic variability has long been recognized as limiting the range of operating conditions of spark ignition engines, in particular, under lean and highly diluted operation conditions. The cyclic combustion variations can be characterized by the pressure parameters, combustion parameters, and flame front parameters. The coefficient of variation in indicated mean effective pressure ($COV_{IMEP}$) defines the cyclic variability in indicated work per cycle, and it has been found that vehicle driveability problems usually result when $COV_{IMEP}$ exceeds about 10%. For analysis of the cyclic variability in SI engines at idling, the results show that cyclic variability by the $COV_{IMEP}$ or the coefficient of variation in maximum pressure can be explained and may be consequently reduced by the help of the optimum spark timings.

• 한국자동차공학회논문집
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• 제4권2호
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• pp.221-229
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• 1996

The engine speed fluctuation at idle operation mainly comes from cyclic variation of combustion in SI engine. In the present study, engineering model that is representing the cyclic variation of combustion was proposed for the sub-model of the engine cycle simulation. From the observed behaviors of the mass burn rates, probability density functions for the parameters of Wiebe function were defined. The mass burn rate of each cycle is obtained by Monte Cralo perturbation method with the probability function. The simulation results shows that trends of cylinder pressure variation and imep distribution follow up with those of experimental results at idle condition.

• 한국세라믹학회지
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• 제43권12호
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• pp.775-780
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• 2006

Mechanical and electrical performance of anode-supported SOFC single cells were analyzed after thermal cyclic operation. The experiments of thermal cyclic cell-operation were carried out four times and performance of each cell was measured at different temperatures of 650, 700, and $750^{\circ}C$, respectively. As increasing the number of thermal cycle test, single cells showed poor I-V characteristics and lower 4-point bending strength. The anode polarization was also measured by AC-impedance analysis. The observation of the microstructure of the anodes in single cells proved that the average particle size of Ni decreased and the porosity of anode increased. It is thought that the thermal cycle caused the degradation of performance of single cells by reducing the density of three-phase boundary region.

• 오토저널
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• 제14권3호
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• pp.90-101
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• 1992

An experimental study was carried out to investigate the characteristics of cyclic variability of combustion in a single cylinder spark ignition engine. Cylinder pressure of 240 consecutive cycles were measured for various engine operating conditions. From these data, a thermody-n amic analysis was performed for the typical cases in order to identify the cause and effect re -lation of the cyclic variation. In determining the number of cycles required for estimating the coefficient of variation of IMEP and so on, the oprating conditions must be cosidered to fit the objective of the analysis. It is thought that the variation in early flame stage is amplified through the flame propagation and results in the phase change between pressure and volume, which can be the major reason of cyclic variation of IMEP in case of lean operation.