• Journal of Astronomy and Space Sciences
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• v.35 no.1
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• pp.7-18
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• 2018

We have investigated the intensities and full width at half maximum (FWHM) of the high dispersion spectroscopic N III emission lines of AG Peg, observed with the Hamilton Echelle Spectrograph (HES) in three different epochs at Mt. Hamilton's Lick Observatory. The earlier theoretical Bowen line study assumed the continuum fluorescence effect, presenting a large discrepancy with the present data. Hence, we analyzed the observed N III lines assuming line fluorescence as the only suitable source: (1) The O III and N III resonance line profiles near ${\lambda}$ 374 were decomposed, using the Gaussian function, and the contributions from various O III line components were determined. (2) Based on the theoretical resonant N III intensities, the expected N III Bowen intensities were obtained to fit the observed values. Our study shows that the incoming line photon number ratio must be considered to balance at each N III Bowen line level in the ultraviolet radiation according to the observed lines in the optical zone. We also found that the average FWHM of the N III Bowen lines was about $5km{\cdot}s^{-1}$ greater than that of the O III Bowen lines, perhaps due to the inherently different kinematic characteristics of their emission zones.

• Current Photovoltaic Research
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• v.7 no.3
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• pp.65-70
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• 2019

As a demand of higher power photovoltaic modules, shingled, multi-busbar, half-cell, and bifacial techniques are developed. Multi-busbar module has advantage for large amount of light havesting. And, half-cell is high power module for reducing resistive losses and higher shade tolerance. Recently, researches on multi-busbar is focused on reliability according to adhesion and intermetallic compound between Sn-Pb solder and Ag electrode. And half-cell module is researched to comparing with full-sized cell module for structure difference. In this study, we investigated the factors affecting to efficiency and adhesion of multi-wires half-cell module according to wire thickness, solder thickness, and flux. The results of solar simulator and peel test was that peel strength and efficiency of soldered cell is not related. But samples with flux including high solid material showed high efficiency. The results of FE-SEM and EDX line scan on cross-section between wire and Ag electrode for different flux showed thickness of solder joint between wire and Ag electrode is increasing through solid material increasing. Flux including high solid material would affect to solder behavior on Ag electrode. Higher solid material occurred lower growth of IMC layer because solder permeate to sider of wire ribbon than Ag electrode. And it increased fill factor for high efficiency. In soldering process, amount of solid material in flux and solder thickness are the factor related with characteristic of soldered photovoltaic cell.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2293-2298
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• 2011

In this paper, A tag antenna structure for RFID application with resonant frequency of 920MHz is proposed using the meander line technique and Evolution Strategy. Miniaturization structure design for a tag antenna is performed by structure combining the half-wave dipole with a meander line. To achieve this, an interface program between a commercial EM analysis tool and the optimal design program is made for implementing the evolution strategy technique that seeks a global optimum of the objective function through the iterative design process consisting of variation and reproduction. The optimized tag antenna size is 63mm ${\times}$ 15mm ${\times}$ 1mm. And the proposed antenna is realized on FR-4 substrate (${\epsilon}_r=4.4$, $tna{\delta}=0.02$).

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.707-711
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• 1989

This system exchange half-duplex serial data at 1200 baud by FSK modulating a carrier frequency at 200KHz over the 110V A.C. power line. Transmitter output voltage to A.C. line is 4V p-p and line sensitivity is selected 2.54mV because CISPR Noise limitation is $66dB{\mu}V$ at 150 ${\sim}$ 500KHz. The designed and realized system has abtained system margin of 58 dB and probability of error, Pe = $1.78{\times}10^{-7}$ was obtained

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.968-969
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• 2015

This paper proposes a novel analysis method for calculating inverter DC bus capacitance and line reactor parameters. In the realization process, DC bus capacitance parameter, and ripple current, life of DC bus capacitor, interaction between DC bus capacitance can be calculated by using Newton-Raphson procedure. The design scheme of DC bus capacitor and line reactor, specific parameters such as capacitance, loss, ripple current, central average temperature, life, ripple current, loss, size, central temperature of the reactor were given. Simulation results show that this scheme can accurately calculate the DC bus capacitance and line reactor parameters. Compared with calculation result of references, cost and volume are half. The indicators meet the demand of practical engineering. It had affirmed precision of the analytical method and verified correctness and feasibility of this method.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.86-88
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• 1999

We investigated the current limiting characteristics of resistive and inductive SFCLs with $100{\Omega}$ of quench impedance for a line-to-line fault in the 154 kV transmission system. The fault simulation at the phase angles $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$ showed that the resistive SFCL limited the fault current less than 15 kA without any DC component after one half cycle from the instant of the fault. On the other hand, the inductive SFCL suppressed the current below 13 kA, but with $2{\sim}3\;kA$ of DC component which decreased to zero in 6 cycles. We concluded that the inductive SFCL had higher performance in current limiting but the resistive SFCL was better from the view point of DC components.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1441-1446
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• 2008

Seoul Metro Line 9 (SML9) is the first subway line that private capital invests in Korea. SML9 will cross Seoul, linking the Gimpo Airport to the Gangnam district (25.5km) opening in the first half of 2009. SML9 has a new model in Korea constructed by metropolitan government and private company and operated by specialized public transportation service provider. SML9 is confronted with tough environment of stagnated public transportation and strong competitor, Olympic city expressway. And SML9 is under pressure for showing high efficiency as non-governmental organization from both customers and government. Consequently SML9 must lead the maximum efficiency by using its material and human resource. It is necessary that SML9 raise a competitive power and display its ability in active collaboration with relative organization and company. Hereupon, I propose renovation plans from viewpoint of operation field of SML9, (1) efficient train scheduling regime focusing on the combination of express and local train (2) close connection of other mean of transportation and (3) effective connection convention with Airport Railroad (AREX) as the line connected directly.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2345-2347
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• 2005

In this paper, impedance characteristics of overhead medium-voltage (MV) power lines is reported for power line communication (PLC) over an MV power line network. For analysis, a two-port equivalent network model of MV power lines is derived. By applying the transmission line theory, reflection behavior and impedance of power lines are investigated. For verification, impedance of power lines is measured at a test field for an MV PLC. The results show that impedance of MV power lines is between $200{\Omega}$ and $300{\Omega}$ and converges to a half of their characteristic impedance.

• Journal of The Korean Astronomical Society
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• v.40 no.3
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• pp.67-82
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• 2007

The basic building block of solar filaments/prominences is thin threads of cool plasma. We have studied the spectral properties of velocity threads, clusters of thinner density threads moving together, by analyzing a sequence of $H{\alpha}$ images of a quiescent filament. The images were taken at Big Bear Solar Observatory with the Lyot filter being successively tuned to wavelengths of -0.6, -0.3, 0.0, +0.3, and +0.6 ${\AA}$ from the centerline. The spectra of contrast constructed from the image data at each spatial point were analyzed using cloud models with a single velocity component, or three velocity components. As a result, we have identified a couple of velocity threads that are characterized by a narrow Doppler width($\Delta\lambda_D=0.27{\AA}$), a moderate value of optical thickness at the $H{\alpha}$ absorption peak($\tau_0=0.3$), and a spatial width(FWHM) of about 1". It has also been inferred that there exist 4-6 velocity threads along the line of sight at each spatial resolution element inside the filament. In about half of the threads, matter moves fast with a line-of-sight speed of $15{\pm}3km\;s^{-1}$, but in the other half it is either at rest or slowly moving with a line-of-sight velocity of $0{\pm}3km\;s^{-1}$. It is found that a statistical balance approximately holds between the numbers of blue-shifted threads and red-shifted threads, and any imbalance between the two numbers is responsible for the non-zero line-of-sight velocity determined using a single-component model fit. Our results support the existence not only of high speed counter-streaming flows, but also of a significant amount of cool matter either being at rest or moving slowly inside the filament.

• The International Journal of Costume Culture
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• v.2 no.2
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• pp.80-96
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• 1999

This research focused on pattern adjustments of the stable knit garment for women. Fourteen different types of the knitted fabrics by 12 gauge, computerized flat bed machines were cut in as one half of the torso front, one half of the torso back, and one side of the sleeves for each of them. Guidelines such as the center front, the center back, the armhole, the bust-line, the waistline, the hip-line the hemline were basted on the torso patterns in the knitted fabrics. Also the grain-line, the elbow-line, and the hemline were basted on the one side of the sleeves in the same as above knitted fabrics. The torso patterns in the knitted fabrics were exhibited on the dress-forms on top of the torso patterns in Muslin, which also have the same guidelines drawn on. The distances between the guidelines on Muslin and those on the knitted fabrics for each set of the sample fabrics were measured every three days for two weeks. The fabric properties of the fourteen knitted fabrics such as fiber contents, stitch density both in the wale and course directions, weight, thickness, stretch & recovery, residual shrinkage, relaxation and drapability were laboratory tested for how these were related to finished appearance of 12 gauge, computerized flat knit garments and also in order to prove the fourteen knitted fabrics fall to a category of such as the stable knit. The results from the investigation revealed that six fabric properties such as stitch density, thickness, stretch recovery, residual shrinkage and relaxation were not so much significant factors as weight and drapability. In conclusion, fabric weight, and drapability of the fabric resulting from fiber contents were the cause of final appearance distortion of garment. When adapting patterns for stabilized, 12 gauge, computerized flat knitted fabrics, the fiber contents of the fabrics should be taken into consideration to reduce the production cost and produce better-fit garments.