• 대한기계학회논문집A
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• 제20권4호
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• pp.1202-1215
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• 1996

In this study, in order to achieve the uniformity of mechanical properties and microstructures of a hot-rolled coil in the transversal direction, the edge mask device is newly device is newly developed and installed at the upper laminar-flow cooling head in the run out table, which controls the transversal temperature of strip with enco panel and bar edge heater. The device that is transversally movable prevents the temperature drop of strip edge by blocking the cooling water into the strip edge. So, the pattern of edge mask set-up condition of the device was derived by analyzing the characteristics of strip temperature and mechanical properties according to the on-line application of edge mask.

• 천문학회보
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• 제45권1호
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• pp.61.1-61.1
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• 2020

We examine the HI gas kinematics and distribution of galaxy pairs in group or cluster environment from high-resolution Australian Square Kilometre Array Pathfinder (ASKAP) WALLABY pilot observations. We use 22 well-resolved galaxies in the Hydra cluster of which 4 galaxies are visually identified as pairs and others are isolated ones. We perform profile decomposition of HI velocity profiles of the galaxies using a new tool, BAYGAUD which enables us to separate a line-of-sight velocity profile into an optimal number of Gaussian components based on Bayesian MCMC techniques. All the HI velocity profiles of the galaxies are decomposed into kinematically cold or warm gas components with their velocity dispersion, 4~8 km/s or > 8 km/s, respectively. We derive the mass fraction of the kinematically cold gas with respect to the total HI gas mass, f = log10(M_cold / M_HI), of the galaxies and correlate them with their dynamical mass. The cold gas reservoir of the paired galaxies in the Hydra cluster is found to be relatively higher than that of the isolated ones which show a negative correlation with the dynamical mass in general.

• 설비공학논문집
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• 제24권1호
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• pp.37-44
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• 2012

This paper describes energy loss in a pipe line of refuse collecting system. Analysis of energy loss in a pipe line is the decisive factor in a design of refuse collecting system. Using the results of energy loss analysis, we can determine the power of turbo-blower. The flow characteristics of the pipe line with refuse bags were analyzed by three-dimensional CFD. The refuse bag is modeled by using the shape obtained from profile measurement. Friction factors were calculated with changing the refuse bag size, mixing ratio and Reynolds number. And drag coefficients were calculated using the CFD results. From the results we can calculate energy loss in a pipe line of refuse collecting system and predict the capacity of turbo-blower.

• 대한전자공학회논문지SP
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• 제41권3호
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• pp.129-137
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• 2004

이 논문은 Gabor 필터를 이용하여 두 서명 사이의 유사도를 계산하는 온라인 서명 검증 방법을 제안한다. 온라인 서명들의 유사도를 계산하기 위해서는 두 입력 서명의 각 위치 사이의 시간적인 대응 관계를 정확하게 구하는 것이 중요하다. 그러나 DP(dynamic programming) 매칭을 이용하는 기존의 포인트 매칭 방법은 시간이 많이 소요되는 단점이 있었다. 이 논문에서는 Gabor 필터의 위상 출력을 이용하여 두 서명 사이의 시간적인 대응 관계를 빠르게 추정하는 방법을 제안한다. 제안된 방법에서는 서명의 상이도로서 두 가지 척도를 정의한다. 첫째, 추정된 지역적 시간 변이로부터 두 서명사이의 시간적 상이도를 구하고, 둘째, 두 서명 특징 프로파일의 시간적 대응 관계를 이용하여 시간 정보가 보정된 특징 프로파일 상이도를 구한다. 제안된 방법은 고정된 길이의 코드로 코드화되어 기존의 DP 매칭을 사용하는 시간적 변이 추정 방법보다 30배 이상 빠른 속도로 서명을 비교할 수 있다.

• 천문학회지
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• 제27권1호
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• pp.1-11
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• 1994

We have observed the emission of $HC_3N$ J=4-3, 5-4,10-9 and 12-11 transitions toward the Sgr B2 central region in an area of $150'\times150'$ with resolutions of 16'-48'. The intensities and central velocities of line profiles show significant variations with positions. In contrast to the intensities of the low J-level transitions which gradually increase from the central source toward the outside region, the $HC_3N$ emission of the high J-level transition become stronger toward 'the central radio continuum source MD5. Systematic change in the radial velocity of each line profile occurs along north-south direction. There are a few peaks in most line profiles, and these indicate that there are multiple velocity components along the line of sight. Distributions of excitation temperature and column density which were estimated from the excitation calculations show the existence of a small $(1\times2pc),\;hot\;(T_{ex}>50K)$ core which contains two temperature peaks at-15' east and north of MD5. The column density of $HC_3N\;is\;(1-3)\times10^{14}cm^{-2}$ Column density at distant position from MD5 is larger than that in the central region. We have deduced that this 'hot-core' has a mass of 105M 0, which is about an order of magnitude larger than those obtained by previous studies.

• 천문학회지
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• 제44권2호
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• pp.59-65
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• 2011

A small number of active galactic nuclei are known to exhibit prominent double peak emission profiles that are well-fitted by a relativistic accretion disk model. We develop a Monte Carlo code to compute the linear polarization of a double peaked broad emission line arising from Thomson scattering. A Keplerian accretion disk is adopted for the double peak emission line region and the geometry is assumed to be Schwarzschild. Far from the accretion disk where flat Minkowski geometry is appropriate, we place an azimuthally symmetric scattering region in the shape of a spherical shell sliced with ${\Delta}{\mu}=0.1$. Adopting a Monte Carlo method we generate line photons in the accretion disk in arbitrary directions in the local rest frame and follow the geodesic paths of the photons until they hit the scattering region. The profile of the polarized flux is mainly determined by the relative location of the scattering region with respect to the emission source. When the scattering region is in the polar direction, the degree of linear polarization also shows a double peak structure. Under favorable conditions we show that up to 0.6% linear polarization may be obtained. We conclude that spectropolarimetry can be a powerful probe to reveal much information regarding the accretion disk geometry of these active galactic nuclei.

• Journal of Power Electronics
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• 제10권3호
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• pp.285-292
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• 2010

This paper presents a current mode integrated control technique (CM-ICT) using a modified voltage space vector modulation (MSVM) for Z-source inverter (ZSI) fed induction motor drives. MSVM provides a better DC voltage boost in the dc-link, a wide range of AC output voltage controllability and a better line harmonic profile. In a voltage mode ICT (VM-ICT), the outer voltage feedback loop alone is designed and it enforces the desired line voltage to the motor drive. An integrated control technique (ICT), with an inner current feedback loop is proposed in this paper for the purpose of line current limiting and soft operation of the drive. The current command generated by the PI controller and limiter in the outer voltage feedback loop, is compared with the actual line current, and the error is processed through the PI controller and a limiter. This limiter ensures that, the voltage control signal to the Z-source inverter is constrained to a safe level. The rise and fall of the control signal voltage are made to be gradual, so as to protect the induction motor drive and the Z-source inverter from transients. The single stage controller arrangement of the proposed CM-ICT offers easier compensation. Analysis, Matlab/Simulink simulations, and experimental results have been presented to validate the proposed technique.

• 대한전자공학회논문지SD
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• 제40권4호
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• pp.27-33
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• 2003

최근, 원통형 DFB전송 구조들은 다양한 광 소자들과 결합하여 광통신용 필터로 널리 사용되고 있다. 이 원통형 Bragg 격자 구조들의 광 필터특성을 분석하기 위하여 본 논문에서는 Floquet-Babinet의 원리에 의존한 새롭고 쉬운 모드 전송선로 이론 (Modal Transmission-Line Theory)을 제시하였다. 수치해석 결과, 제안한 해석법은 원통형 DFB전송 구조들의 필터특성을 분석하기 위한 유용한 프로그래밍 알고리즘을 제공하고, 다층 원통형 주기 구조들의 전송특성을 분석하기 위하여 쉽게 발전시킬 수 있음을 보였다.

• 한국지구과학회지
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• 제30권5호
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• pp.611-621
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• 2009

Using the spectroscopic data secured with the Hamilton Echelle Spectrograph at Lick Observatory, we found the physical condition of the planetary Nebula NGC 6210. The spectral line profiles of the permitted and forbidden lines have been analyzed using IRAF and StarLink/Dipso. The hydrogen number densities ($N_H$) are 2,000-20,000 $cm^{-3}$, and the electron temperatures are 8,100-10,300 K based on the forbidden lines. The expansion velocities, derived from the Full Width at Half Maximum (FWHM) and the double peak of the line profiles, are in the range of 10 to $45\;kms^{-1}$. The expansion velocities imply a shell structure with an accelerated nebular gas. We also derived abundances from the permitted lines of CII, CIII, NII, NIII, OII, and OIII, which may have been formed through the fluorescence mechanism. NGC 6210 is likely to be evolved from a progenitor of more than $3M_{\bullet}$, which had been born near the Galactic plane.

• 한국자기학회지
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• 제22권3호
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• pp.73-78
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• 2012

본 연구에서는 Argyres-Sigel의 투영 연산자 방법을 단일 벽 탄소 나노튜브(SWNT)의 zigzag(10,0)에 직접 적용하여 이를 운동방정식의 형태로 만들어 선모양 함수를 구하는 방법을 사용하였다. 선모양 함수의 실수 부분인 선 너비는 저온 영역(T < 200K)에서 온도의 영향에 거의 무관한 것으로 조사되었다. 이는 온도에 관여하는 페르미-디랙 분포함수가 선모양 함수에 거의 영향을 작용하지 않기 때문인 것으로 생각된다. 고온 영역(T > 200K)에서는 선 너비가 다소 단조롭게 증가하는 것으로 나타났으며, 이는 음향 포논의 영향에 기인하는 것으로 보인다. 그리고 SWNT의 전자스핀이완 시간은 $1.4{\times}10^{-6}\;s$으로 계산되었다.