• 천문학논총
• /
• 제15권spc1호
• /
• pp.113-118
• /
• 2000

A magnetic cataclysmic variable has a rotating magnetic white dwarf which accretes matter from its late type companion. Kim & Beuermann (1995) presented a phenomenological model of the accretion from its surrounding structure e.g., a disk into the magnetosphere of the white dwarf, and presented results for the spin modulated X-ray spectrum and light curves. Using this model, we calculate the optical continuum and line emission which result from reprocessing of X-rays in the accretion stream within the magnetosphere. Penning (1985) suggested the observed spin-modulated radial-velocity variations might result from reprocession of X-rays in the disk. We, however, find the radiation can be originated from the magnetosphere accretion stream. We use the same geometrical model to calculate the optical and the X-ray behaviour. The results from the two wavelength bands are internally consistent. We conclude that this approach will increase the diagnostic accuracies of the results.

• 천문학회보
• /
• 제39권2호
• /
• pp.87.2-87.2
• /
• 2014

Symbiotic stars and quasars exhibit prominent $H{\alpha}$ emission lines often accompanied with broad wings. $H{\alpha}$ emission nebulae in these objects are proposed to be optically thick to resonance scattering. The transfer of $H{\alpha}$ line photons are further complicated by the existence of another scattering channel leading to re-emission of $Ly{\beta}$. In this work are develop a Monte Carlo code to simulate the transfer of $H{\alpha}$ line photons incorporating the scattering channel into $Ly{\beta}$. We show various line profiles of $H{\alpha}$ and $Ly{\beta}$ emergent from our model nebulae. It is shown that temperature is a critical parameter which controls the ratio of emergent $Ly{\beta}$ flux to that of $H{\alpha}$.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 추계학술대회논문집
• /
• pp.986-989
• /
• 2004

The method of measurement for laboratory tests on noise emission from appliances and equipment used in water supply installations is specified in ISO 3822-1 This part of standard gives detailed descriptions for mounting and operating in-line valves and appliances, which control the flow, pressure or temperature of the water in water supply installations in such laboratory tests.

• 방사선산업학회지
• /
• 제8권1호
• /
• pp.59-63
• /
• 2014

Proton Induced X-ray Emission (PIXE) is a MeV ion beam analysis method for use with particle accelerators. PIXE uses low-energy charged particles as an excitation mechanism to generate characteristic x-ray emission from each element in a target. In PIXE analysis, the beam current used is from a few nA to several tens of nA. Chosun University (Cyclotron Research Center) designed a $50{\mu}A$ beam line from the 13 MeV cyclotron for use with a PIXE analysis system, as well as performing beam transport line optimization research. In this study, the beam line operation conditions for the optimization process of beam transport and beam characteristics are shown.

• 천문학논총
• /
• 제15권spc1호
• /
• pp.133-145
• /
• 2000

Symbiotic stars are known as binary systems with both cool and hot components with enshrounding nebulous gas. The cool component, M-type giant, is presumably loosing its mass into a hot white or main sequence companion star through the inner Lagrangian point. The lines emit from the ionized nebulous region around the hot star while the mass loss or accretion activity is believed to be the main cause of sudden variation of the continuum and line fluxes. We selected 17 symbiotics for which the emission line fluxes were measured from the IUE SWP, LWR data, to find variability of spectrum. We also investigated the periodic variation of emissions or eclipsing effect from the IUE lines. All of our symbiotics show very high electron densities in the emission regions. For other optical symbiotics, the observations had been carried in 1999 with BOAO mid-resolution spectrometer. We classified symbiotics based on their outburst activities, or emission line characteristics, i.e., $OVI{\lambda}6830.\;The\;OVI{\lambda}6830$ emission lines are also found in S-type symbiotics, which have been known as charateristics of D-types.

• 천문학회보
• /
• 제35권2호
• /
• pp.40.2-40.2
• /
• 2010

Polycyclic aromatic hydrocarbon (PAH) features have emerged as one of the most important infrared (IR) features since these PAH features dominate mid-IR spectra of galaxies and are ubiquitous within galactic and extragalactic objects. These PAH features have the potentials to become reliable star formation rate (SFR) proxies and diagnostics of physical conditions of interstellar medium, such as ionization states of dust grains and grain sizes. While constructing an unbiased library of 44 sample galaxies selected from 5MUSES sample, AKARI mJY Unbiased Survey of Extragalactic Sources in 5MUSES (AMUSES) intends to measure and to calibrate the PAH 3.3 mm emission feature which has not been studied extensively due to its weak strength and dearth of capable instruments. Out of 20 target galaxies, we detected the 3.3mm feature from eight galaxies and measured their line strengths, line widths and line ratios with other PAH emission features. Sample galaxies whose spectral energy distributions (SEDs) are classified as starburst-type have clearly stronger 3.3mm emission features than ones with AGN-type SEDs. We also found that there is a correlation between the PAH 3.3mm luminosity and total IR luminosity within our sample galaxies, albeit a large scatter. We further discuss implications of our results.

• 천문학논총
• /
• 제22권4호
• /
• pp.89-95
• /
• 2007

The warm ionized medium (WIM) outside classical H II regions is a fundamental gas-phase constituent of the Milky Way and other late-type spiral galaxies, and is traced by faint emission lines at optical wavelengths. We calculate the photoionization models of the WIM in the Galaxy by a stellar UV radiation with the effective temperature 35,000 K assuming not only spherical geometry but also plane parallel geometry, and compare the results with the observed emission line ratios. We also show the dependence of the emission line ratios on various gas-phase abundances. The emergent emission-line ratios are in agreement with the average-values of observed ratios of [S II] ${\lambda}6716/H{\alpha}$, [N II] ${\lambda}6583/H{\alpha}$, [O I] ${\lambda}6300/H{\alpha}$, [O III] ${\lambda}5007/H{\alpha}$, He I ${\lambda}5876/H{\alpha}$. However, their extreme values could not be explained with the photoionization models. It is also shown that the addition of all stellar radiation from the OB stars in the Hipparcos stellar catalog resembles that of an O7-O8 type star.

• 전력전자학회논문지
• /
• 제2권2호
• /
• pp.41-48
• /
• 1997

최근 고품질 전원공급에 관한 요구가 증대되면서 장치에서 발생되는 고차 고조파에 의하여 다른 기기의 오동작을 방지하기 위한 EMI(Electro Magnetic Interferencfe)에 관한 연구가 전력전자분야를 중심으로 활발하게 진행되고 있다. 따라서 본 논문에서는 3상 전력변환 장치인 다이오드 정류기와 PWM 컨버터에서 PI 전류제어방식과 히스테리시스 전류제어방식을 대상으로 LISN(Line Impedance Stabilization Network)을 사용하여 제어방식의 변화와 스위칭 주파수 변동에 따른 전도성 EMI 방출량을 측정하여 비교하였다.

• 천문학회보
• /
• 제38권1호
• /
• pp.53-53
• /
• 2013

We present preliminary results of far-infrared(FIR) study of the supernova remnant(SNR)s in the Large Magellanic Cloud using the Herschel HERITAGE (HERschel Inventory of The Agents of Galaxy Evolution) data set. HERITAGE provides FIR data covering the entire LMC at 100,160, 250, 350, and 500 um. In order to confirm FIR emission associated with SNRs, we refer to Magellanic Cloud Emission-Line Survey (MCELS) H-alpha & SII data, Spitzer surveying the Agents of a Galaxy's Evolution (SAGE) Multiband Imaging Photometer (MIPS) 24um & 70um data, Chandra Supernova Remnants Catalog, and ATCA 4.8GHz continuum images of Dickel et al. (2005). Among 47 SNRs in the LMC, 7 SNRs show associated FIR emission. We present multi-wavelength view of 5 SNRs; DEM L249, N49, N63A, N132D, and the SNR in N4. N49 and N132D show morphological correlation in FIR and X-ray, suggesting that the FIR emission is from dust grains collisionally heated by X-ray emitting plasma. The FIR emission of N63A resembles H-alpha emission, which implies that the FIR line radiation could be dominant. The FIR images of the rest two objects, DEM L249 and SNR in N4, show no correlation to the other-waveband images.

• 한국대기환경학회지
• /
• 제20권4호
• /
• pp.539-553
• /
• 2004

Up to the present time, many methods to estimate emissions from a particular diesel engines have wholly depended on the quantity of diesel fuel consumed. Then, the recommended emission factors were normalized by fuel consumption, and further total activity was estimated by the total fuel consumed. One of main purposes in the study is newly to develop emission factors for the railroad diesel rolling stock (RDRS) and to estimate a total amount of major gaseous pollutants from the RDRS in Korea. Prior to develop a Korean mode emission factor. the emission factor from the USEPA was simply applied for comparative studies. When applying the USEPA emission factors, total exhaust emissions from the RDRS in Korea were estimated by 28,117tons of NOx, 2,832.3tons of CO, and 1,237.5tons of HC, etc in 2001. In this study, a emission factor for the RDRS, so called the KoRail mode (the Korean Railroad mode) has been developed on the basis of analyzing the driving pattern of the Gyeongbu-Line especially for the line-haul mode. Explicitly to make the site specific emission factors, many uncertainty problems concerning weighting factors for each power mode, limited emission test, incomplete data for RDRS, and other important input parameters were extensively examined. Total exhaust emissions by KoRail mode in Korea were estimated by 10,960tons of NOx, and 4,622tons of CO, and so on in the year of 2001. The emissions estimated by the USEPA mode were 2.6 times higher for NOx, and 1.6 times lower for CO than those by the KoRail mode. As a conclusion, based on the emission calculated from both the USEPA mode and the KoRail mode, the RDRS is considered as one of the significant mobile sources for major gaseous pollutants and thus management plans an(1 control strategies for the RDRS must be established to improve air quality near future in Korea.