• 천문학회보
• /
• 제42권1호
• /
• pp.58.4-59
• /
• 2017

Sanduleak's star is a suspected symbiotic binary located in the Large Magellanic Cloud. It is known that it has a giant jet with physical size ~ 14pc. Its spectrum shows two strong emission bands at $6825{\AA}$ and $7082{\AA}$, which are originated from Raman-scattering of O VI by neutral hydrogen atoms. We present the high-resolution spectrum of Sanudleak's star obtained with MIKE at the Magellan-Caly telescope to investigate the O VI emission region based on the profiles of the two Raman features. In this spectrum, it is noted that the Raman $6825{\AA}$ feature exhibits a single broad peak profile, which is in high contrast with a clear triple peak profile of the Raman $7082{\AA}$ feature. In our analysis we suggest that the O VI emission region consist of three main emission parts: an accretion disk, a bipolar outflow and an optically thick, compact component surrounding the white dwarf. By performing Monte Carlo simulation we constrain the representative column density of the H I scattering region N_HI ~1${\times}$10^23 cm^-2, which is in accordance with the observed flux ratio in the two Raman features F(6825)/F(7082) ~ 4.5.

• Nuclear Engineering and Technology
• /
• 제4권2호
• /
• pp.116-131
• /
• 1972

Li$^{7}$ (p, n) Be$^{7}$ 원자핵반응에서 Li target의 두께와 입사양자의 에너지를 적절히 선정하므로써 1-n sec 파동 Van de Graaff 가속도로부터 keV 영역에서의 연속중성자spectrum을 발생시키고 92% 농축된 5mm 두께의 $B^{10}$ 판과 4개의 4＂$\times$3＂ NaI (T1) 발광체로 이루어진 속중성자검출기를 이용 속중성자 비행시간법에 의한 중성자spectrometer 를 제작하였다. 장치의 에너지 분해능은 50 keV에서 0.3%보다 양호하며 신호대잡음비도 개량되었다. 이를 이용하여 몇가지 분석된 단일동위원소의 전단면적을 측정하고 R-matrix 전자계산 code로 분석하였다. 각 공명에 따르는 스핀식와 공명인수들을 찾아내었다.

• Nuclear Engineering and Technology
• /
• 제55권12호
• /
• pp.4350-4356
• /
• 2023

Radiation detection systems working at high count rates suffer from the overlapping of their output electric pulses, known as pulse pile-up phenomenon, resulting in spectrum distortion and degradation of the energy resolution. Pulse tail extrapolation is a pile-up correction method which tries to restore the shifted baseline of a piled-up pulse by extrapolating the overlapped part of its preceding pulse. This needs a mathematical model which is almost always nonlinear, fitted usually by a nonlinear least squares (NLS) technique. NLS is an iterative, potentially time-consuming method. The main idea of the present study is to replace the NLS technique by an integration-based non-iterative method (NIM) for pulse tail extrapolation by an exponential model. The idea of linear extrapolation, as another non-iterative method, is also investigated. Analysis of experimental data of a NaI(Tl) radiation detector shows that the proposed non-iterative method is able to provide a corrected spectrum quite similar with the NLS method, with a dramatically reduced computation time and complexity of the algorithm. The linear extrapolation approach suffers from a poor energy resolution and throughput rate in comparison with NIM and NLS techniques, but provides the shortest computation time.

• Journal of Radiation Protection and Research
• /
• 제35권2호
• /
• pp.77-80
• /
• 2010

The spectroscopy toolkit has been developed and tested. The toolkit consists of a CsI(Tl)/PIN diode detector, integrated electronics, and a multi.channel.analyzer and its size was 40 cm(width) by 20 cm(length) by 6 cm(high). It is compact, very portable and simpler and cheaper compared to the conventional spectroscopy system. The gamma energy resolutions of the toolkit were 7.9% for the 660 keV of $^{137}Cs$ and 4.9% for 1,332 keV of $^{60}Co$ respectively. The linearity for gamma energies was good. When the energy spectrum of a ceramic sample containing $^{232}Th$ was measured with the spectroscopy toolkit for 20 minutes, there were significant peaks of the heavy metal. These results show that the resolution of the spectroscopy toolkit is sufficient to accumulate a quality spectrum in a few minutes by using weak, encapsulated commercial sources. Furthermore a toolkit experiment that how to measure energy spectra using the toolkit, and how to identify specific isotopes in a pottery piece, could be widely adopted for education and even for more sophisticated and higher level experiments.

• 대한영상의학회지
• /
• 제84권5호
• /
• pp.1031-1046
• /
• 2023

손가락은 일상생활과 스포츠 활동 중에 가장 흔하게 손상될 수 있는 구조물이다. 손가락 손상은 손가락의 뼈와 인대, 연골을 포함한 연부조직까지 다양한 구조물의 손상을 포함한다. 특수 표면코일을 이용한 고해상도 3 테슬라 자기공명영상을 이용하여 복잡한 연부조직 구조물들을 평가할 수 있다. 손가락과 손의 기본 해부학과 흔한 병변의 자기공명영상 소견들에 대한 기존의 보고들이 있다. 손가락의 인대, 건, 도르래 등 여러 구조물의 기본 해부학과 흔한 외상성 병변의 영상학적 소견의 이해는 다양한 손의 외상성 병변에 대한 정확한 평가를 가능하게 한다. 본 눈문에서는 손가락의 기본 해부학적 구조 및 흔한 외상의 자기공명영상 소견을 복습하고, 실제 수술장 소견과 연관 지어 이해를 돕고자 한다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
• /
• pp.86-89
• /
• 2006

Ocean color remote sensing community currently uses the different solar irradiance spectra covering the visible and near-infrared in the calibration/validation and deriving products of ocean color instruments. These spectra derived from single and / or multiple measurements sets or models have significant discrepancies, primarily due to variation of the solar activity and uncertainties in the measurements from various instruments and their different calibration standards. Thus, it is prudent to examine model-to-model differences and select a standard reference spectrum that can be adopted in the future calibration and validation processes, particularly of the first Geostationary Ocean Color Imager (GOCI) onboard its Communication Ocean and Meterological Satellite (COMS) planned to be launched in 2008. From an exhaustive survey that reveals a variety of solar spectra in the literature, only eight spectra are considered here seeing as reference in many remote sensing applications. Several criteria are designed to define the reference spectrum: i.e., minimum spectral range of 350-1200nm, based completely or mostly on direct measurements, possible update of data and less errors. A careful analysis of these spectra reveals that the Thuillier 2004 spectrum seems to be very identical compared to other spectra, primarily because it represents very high spectral resolution and the current state of the art in solar irradiance spectra of exceptionally low uncertainty ${\sim}0.1%.$ This study also suggests use of the Gueymard 2004 spectrum as an alternative for applications of multispectral/multipurpose satellite sensors covering the terrestrial regions of interest, where it provides spectral converge beyond 2400nm of the Thuillier 2004 spectrum. Since the solar-activity induced spectral variation is about less than 0.1% and a large portion of this variability occurs particularly in the ultraviolet portion of the electromagnetic spectrum that is the region of less interest for the ocean color community, we disregard considering this variability in the analysis of solar irradiance spectra, although determine the solar constant 1366.1 $Wm^{-2}$ to be proposed for an improved approximation of the extraterrestrial solar spectrum in the visible and NIR region.

• 한국지구물리탐사학회:학술대회논문집
• /
• 한국지구물리탐사학회 2005년도 공동학술대회 논문집
• /
• pp.261-266
• /
• 2005

인공위성 측지학의 발달로 최근 들어 정밀도와 해상도가 높아진 중력포텐셜 모델들이 공개되었다. 근래에 가장 많이 사용되는 EGM96과 CHAMP, GRACE 등의 저고도 위성자료를 기반으로 하는 가장 최근의 EIGEN-CG01C 모델을 이용하여 한반도와 인근지역을 포함하는 $123^{\circ}{\sim}132^{\circ}$ E, $33^{\circ}{\sim}43^{\circ}$ N의 연구지역에서 지오이드와 중력이상을 계산하고, 비교 검토하였다. 두 모델은 지오이드와 중력이상에서 0.90이상의 매우 높은 상관관계를 가지고 있으나, Amplitude 분석에서 EIGEN-CG01C 모델이 고주파영역이 우세한 것으로 나타났다. 두 모델을 통해 계산된 중력이상에서 북한지역 및 황해 연안 일부에서 다소 차이를 보인다. Power spectrum 분석을 통하여 대규모 지구조나 지하자원 탐사에 유용하게 활용될 수 있는 잔여이상을 계산하였다.

• 천문학회지
• /
• 제29권spc1호
• /
• pp.341-342
• /
• 1996

We present here the solar LOG GF values obtained using the Liege solar at las and the standard solar photospheric models for the spectral lines in the wavelength range ${\lambda}{\lambda}$ 6209 - 6273 ${\AA}$. These log gf values shall be used to interpret a high resolution spectra of the star $\gamma$ Draconics.

• 한국통신학회논문지
• /
• 제28권3A호
• /
• pp.151-156
• /
• 2003

Millimeter waves are potentially useful for high resolution ranging and imaging in low optical visibility conditions such as fog and smoke. Also, They can be used for wide band communications since the currently used spectrum bands are already crowded. However, it is necessary to develop a theoretical and experimental understanding of millimeter wave propagation to assess the performance of millimeter wave systems. The intensity fluctuations and mutual coherence function (MCF) describe atmospheric effects on the millimeter wave propagation. Using the quasi-optical method (QOM), a practical and efficient method is suggested to obtain MCF from the flux measurement in the antenna focal plane.

• 한국광학회:학술대회논문집
• /
• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
• /
• pp.59-64
• /
• 1989

Raman vibrational Q0branch spectra of pure CO are measured by using the technique of quasicw inverse Raman spectroscopy utilizing a pulsed single-frequency laser source. This approach gives enhanced sensitivity compared to earlier work which employed CW lasers, allowing extension of that work to higher accuracy, higher J states, and higher pressure. Fitting laws with pertubation theory and modified energy gap(MEG) theory are described, and the line broadening and shifting coefficients of J=0 to 24 are determined with both fitting laws.