• 천문학회지
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• 제52권1호
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• pp.1-9
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• 2019

We present the results of the spectral and temporal analysis of eight X-ray point sources in five nearby (distance < 20 Mpc) galaxies observed with Chandra. For spectral analysis, an absorbed powerlaw and an absorbed diskblackbody were used as empirical models. Six sources were found to be equally fitted by both the models while two sources were better fitted by the powerlaw model. Based on model parameters, we estimate the X-ray luminosity of these sources in the energy range 0.3 - 10.0 keV, to be of the order of ${\sim}10^{39}ergs\;s^{-1}$ except for one source (X-8) with $L_X>10^{40}ergs\;s^{-1}$. Five of these maybe classified as Ultraluminous X-ray sources (ULXs) with powerlaw photon index within the range, ${\Gamma}{\sim}1.63-2.63$ while the inner disk temperature, kT ~ 0.68 - 1.93 keV, when fitted with the disk blackbody model. The black hole masses harboured by the X-ray point sources were estimated using the disk blackbody model to be in the stellar mass range, however, the black hole mass of one source (X-6) lies within the range $68.37M_{\odot}{\leq}M_{BH}{\leq}176.32M_{\odot}$, which at the upper limit comes under the Intermediate mass black hole range. But if the emission is considered to be beamed by a factor ~ 5, the black hole mass reduces to ${\sim}75M_{\odot}$. The timing analysis of these sources does not show the presence of any short term variations in the kiloseconds timescales.

• 한국군사과학기술학회지
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• 제16권2호
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• pp.207-213
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• 2013

An infrared image synthetic method is proposed for infrared system simulation. The synthesis image uses a background IR image captured from real scene and a target IR modeling image. The radiances related with maximum and minimum temperatures of the background and target images are calculated from the Planck's blackbody equation. Based on them, the background and target images are compensated and synthesized. The proposed method is simulated and the IR target images are generated by RadThermIR software.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1282-1287
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• 2004

The bubble behavior and the radiation mechanism from a laser-induced collapsing bubble were investigated theoretically using the Keller-Miksis equation for the bubble wall motion and analytical solutions for the vapor inside bubble. The calculated time dependent bubble radius is in good agreement with observed ones. The half-width of the luminescence pulse at the collapse point, which was calculated under assumption that the light emission mechanism is black body radiation from the vapor bubble agreed well with observed value of several nanoseconds. The gas content inside the vapor bubble was too small to produce the light emission due to bremsstrahlung.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.462-465
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• 2005

The ITT Industry's Commercial Advanced Geo-Imager (CAGI) which is a recurrent version of imagers used in the GOES series was selected as the COMS Meteorological Imager (MI). The ITT Imager can conduct some special observation such as the space look, blackbody observation, and star sensing regularly or irregularly for its radiometric quality control. Because the GOES-9 which uses an ITT Imager has become operational over the Western Pacific and Eastern Asia positioned at 155 degrees East, the reception of the GOES-9 data is available in Korea. As a step of preparing the COMS MI operation, we conduct the analysis of the GOES-9 imager raw data and operation procedures and compare them with contents of the ITT Imager's manual.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.71-74
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• 2006

Communication Ocean Meteorological Satellite (COMS) is planned to be launched onto Geostationary Earth Orbit in 2008. The meteorological imager (MI) is one of COMS payloads and has 5 spectral channels to monitor meteorological phenomenon around the Korean peninsular intensively and of Asian-side full Earth disk periodically. The MI has on-board radiometric calibration capabilities called 'blackbody calibration' for infrared channels and 'space look' for infrared/visible channels, and radiometric response stability monitoring device called 'albedo monitor' for visible channel. Additionally the MI has on-board function called 'electrical calibration' for the check of imaging path electronics of both infrared and visible channels. The characterization of MI performance is performed to provide the pre-launch radiometric calibration data which will be used for in-orbit radiometric calibration with the on-board calibration outputs. The radiometric calibration of the COMS MI is introduced in the view point of instrument side in terms of in-orbit calibration devices and capabilities as well as the pre-launch calibration activities and expected outputs.

• 한국군사과학기술학회지
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• 제14권2호
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• pp.161-166
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• 2011

The passive open-path Fourier-Transform-Infrared system was implemented for the toxic gas monitoring. Noise Equivalent Differential Temperature(NEDT) was investigated as a system performance evaluation figure and analyzed numerically with the designed parameters. Calculated NEDT was compared with the experimental value in the wavelength region of $700{\sim}1400cm^{-1}^$. The minimum detectable gas concentration was estimated from the obtained NEDT at the absorption wavelength of $SF_6$.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.27-27
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• 2003

Conformations of the +5 to +13 charge state of ubiquitin ions have been studied in the gas phase by an Electron Capture Dissociation (ECD) mass spectrometry (MS) technique. This approach has showed that the conformations of the gaseous ions change from the compact to extended structures as the number of protons on the protein ions increases, consistent with previous collisional cross-section measurements by an ion-mobility MS. However, this observation is in contrast to that of the solution-phase where the unique native structure is usually found. The (un)folding stability and kinetics of these gaseous ions were further investigated experimentally using gradual blackbody-radiation or sudden laser-induced thermal heating, respectively. These studies have provided the evidence that the thermodynamics and kinetics of protein (un)folding in the gas phase are quite different from those of the native aqueous proteins.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.186-189
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• 2002

Real-time thermal image is obtained by thermal imaging systems measuring radiant emittence according to law of Plank's blackbody radiation. The histogram of thermal image is not uniform. The signal bands of background and target are separated and grouped in narrow bands. In such a system, contrast enhancement indispensible to distinguish target from background. In this study, plateau histogram equalization using local histogram is proposed for contrast enhancement.

• Current Optics and Photonics
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• 제5권2호
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• pp.129-133
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• 2021

This study observed the performance of an InAs/GaSb type-II superlattice photodiode with a p-i-n structure for mid-wavelength infrared detection. The 10 ML InAs/10 ML GaSb type-II superlattice photodiode was grown using molecular beam epitaxy. The cutoff wavelength of the manufactured photodiode with Si3N4 passivation on the mesa sidewall was determined to be approximately 5.4 and 5.5 ㎛ at 30 K and 77 K, respectively. At a bias of -50 mV, the dark-current density for the Si3N4-passivated diode was measured to be 7.9 × 10-5 and 1.1 × 10-4 A/㎠ at 77 K and 100 K, respectively. The differential resistance-area product RdA at a bias of -0.15 V was 1481 and 1056 Ω ㎠ at 77 K and 100 K, respectively. The measured detectivity from a blackbody source at 800 K was calculated to be 1.1 × 1010 cm Hz1/2/W at zero bias and 77 K.

• 천문학회지
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• 제56권1호
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• pp.41-57
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• 2023

We measured temporal and emission properties of quiescent magnetars using archival Chandra and XMM-Newton data, produced a list of the properties for 17 magnetars, and revisited previously suggested correlations between the properties. Our studies carried out with a larger sample, better spectral characterizations, and more thorough analyses not only confirmed previously-suggested correlations but also found new ones. The observed correlations differ from those seen in other neutron-star populations but generally accord with magnetar models. Specifically, the trends of the intriguing correlations of blackbody luminosity (L_BB) with the spin-inferred dipole magnetic field strength (B_S) and characteristic age (τ_c) were measured to be L_BB ∝ B^1.5_S and L_BB ∝ τ^-0.6_c, supporting the twisted magnetosphere and magnetothermal evolution models for magnetars. We report the analysis results and discuss our findings in the context of magnetar models.