• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.2
• /
• pp.70-77
• /
• 2007

The application of focused ion beam(FIB) technology has been broadened in the fabrication of nanoscale regime. The extended application of FIB is dependent on complicated reciprocal relation of operating parameters. It is necessary for successful and efficient modifications on the surface of silicon substrate. The primary effect by Gaussian beam intensity is significantly shown from various aperture size, accelerating voltage, and beam current. Also, the secondary effect of other process factors - dwell time, pixel interval, scan mode, and pattern size has affected to etching results. For the process analysis, influence of the secondary factors on FIB micromilling process is examined with respect to sputtering depth during the milling process in silicon material. The results are analyzed by the ratio of signal to noise obtained using design of experiment in each parameter.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.3 no.5
• /
• pp.365-375
• /
• 1991

Confined natural convection due to lateral temperature difference in rectangular enclosures was studied numerically and experimentally for the insulated and the constant temperature enclosures. In the case of insulated enclosure, the flow pattern and heat transfer modes are rather simple depending mainly upon Rayleigh number. In the case of isothermal enclosure, however, the phenomena of flow and heat transfer are somewhat complex and interesting due to the stable thermal gradients and various circumstances resulted from four wall temperature conditions. As a dimensionless variable, to describe properly the flow and heat transfer phenomena in the isothermal enclosure, temperature difference ratio ${\Delta}T_v/{\Delta}T_H$ is newly introduced and this parameter seems to be appropriate in the analysis of results on the effect of stabilizing thermal gradient.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.1
• /
• pp.87-92
• /
• 2016

Van der Pol's oscillators is non-conservative oscillator that having nonlinear damping phenomena. The energy of its system is dissipative at a high amplitude whereas its system creates the energy at low amplitude. In order to identify another behaviors in the Van der Pol oscillator, the periodic external force applied in the Van der Pol oscillator. This paper confirms the pattern of variation for the limit cycle according to parameter variation in order to identify another behaviors in the Van der Pol oscillator.

• Journal of the Korean Ceramic Society
• /
• v.26 no.1
• /
• pp.43-50
• /
• 1989

This experiment was conducted to investigate correlation between microstructure and electrical properties according to Zr/Ti mole ratio in Rhombohedral Phase PZT. Domain behavoir was investigated by the change of thermal expansion coefficient. Piezoelectric properties, the temperature dependence of dielectric constant and the change of dielectric constant before and after poling were measured. Crystal structure, the measurement of lattice parameter were carried by X-ray analysis. Domain pattern before and after poling was examined by SEM.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.717-722
• /
• 2003

The aspect ratio is the main parameter which governs the outer flow pattern and nozzle performance. And in this study, some flow characteristics with the variation of nozzle aspect ratios such as mean pressure distributions along the center line of the outer flow, flow coefficients and the diffusion angles have been experimentally investigated. Through the experimental analysis, the higher aspect ratio was known to decrease the jet kinetic energy because of the friction losses at the outer of nozzle. As the result, it is found that the nozzle performance depends mainly on the aspect ratio of nozzle.

• Journal of Biomedical Engineering Research
• /
• v.11 no.2
• /
• pp.227-232
• /
• 1990

As a part of the study on ultrasonic tissue characterization, conventional ultrasonic imaging system is interfaced to the personal computer to acquire raw ultrasonic signal. One approach for tissue charaterization is performed using the attenuation map to the conventional images and the resulting attenuation map images are compared and inspected inside the region of interest from the viewpoint of pattern analysis. Currently, these methods are applied and modified to effectively find out the differences between the normal control and the patients with liver cirrhosis.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.3
• /
• pp.122-129
• /
• 2001

Exact simulation of conducted EMI in switched mode power supplies is proposed. In order to achieve exact simulation, PSPICE active component ABM model and modified transformer model are proposed. Each model parameter is extracted from measurements and data-books. PSPICE simulation results with high frequency PCB pattern model are accordant with EMI measurements for a 50[W] isolated flyback converter. EMI relations of each component and EMI patterns are analyzed.

• Journal of the Optical Society of Korea
• /
• v.19 no.6
• /
• pp.555-559
• /
• 2015

Coherence length (time) is a key parameter in many classical and quantum optical applications. Two interferometers – Michelson and Young’s double-slit – are used to characterize the temporal coherence of single photons emitted from single terrylene molecules. For quantitative analysis, a dispersion-related distortion in the interference pattern of a Michelson interferometer is carefully corrected by a simple dispersion compensation. Additionally, it has been demonstrated that Young’s interferometer can be used in temporal coherence studies at the single photon level with high accuracy. The pros and cons of the two systems are discussed. The measured coherence lengths in the two systems are consistent with one another under the self-interference interpretations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.415-421
• /
• 1999

This paper indicate that phase resolved partial discharge patterns are investigated on PET films containing artificial void of varing dimensions. In this study, we measured phase-resolved PD patterns and statistical parameter from PET specimens with IGT(insulation/airgap/insulation) structure by IEC 270 standard. Measurement system is the conventional PD detector using digital signal processing technique. The relationship of diameter and location of artificial void was discussed through the difference of $\pi$-q-n distribution and statistical analysis.

• Journal of Environmental Science International
• /
• v.30 no.1
• /
• pp.1-10
• /
• 2021

The purpose of this study is to verify the physiological and psychological benefits of indoor garden to humans and to analyze the comparison according to Type A behavior pattern. The subjects included 18 male university students. Heart rate variation was used as a parameter of physiological assessment, and Semantic Differential (SD), Profile of Mood States-Brief (POMS), and State-Trait Anxiety Inventory (STAI) were used as tools for psychological evaluation. The participants were subjected to a psychological evaluation when they were present in a garden. As a result, the parasympathetic nervous activity was increased in the indoor garden. In the analysis of psychological evaluation, indoor garden improved the positive mood states and decreased negative feelings with significant changes only in Type A group. This study supported that indoor garden can have physiological and psychological relaxing effects, which could be more significant in Type A group than Type B.