• 천문학회보
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• 제42권1호
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• pp.38.2-38.2
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• 2017

We present the observational study toward the multiple outflows around $LkH{\alpha}$ 234 star formation region. The high-resolution, near-IR spectral mapping using the Immersion Grating Infrared Spectrograph (IGRINS) allowed us to distinguish at least four separate outflows with the molecular hydrogen ($H_2$) and forbidden iron ([Fe II]) emission lines. The outflow associated with the radio continuum source VLA 3B is detected in both H2 and [Fe II] emission, while the outflows driven by MM 1, VLA 2 sources were only detected in $H_2$, indicating the different physical conditions of outflows. We confirm the axis of VLA 3B jet, the position angle of ${\sim}240^{\circ}$. We firstly identified the redshifted, near-IR H2 outflow associated with VLA 2, which is coincident with the previous detections of $H_2O$ masers. From the $H_2$ line ratios, we interpret the gas properties of the shock excited blue- and redshifted components, and UV excited surrounding photodissociation region. We also discuss the origin of the high-velocity (|VLSR| > $150km\;s^{-1}$) $H_2$ emission.

• 천문학회보
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• 제44권1호
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• pp.71.1-71.1
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• 2019

We report the first high-resolution (sub-arcminute) large-scale mapping $^{12}CO$ and $^{13}CO$ observations of the molecular clouds associated with the giant outer Galaxy H II region CTB 102 (KR 1). These observations were made using a newly commissioned receiver on the 13.7-m radio telescope at the Taeduk Radio astronomy Observatory (TRAO). Our observations show that the molecular clouds have a spatial extent of $60{\times}35pc$ and a total mass of $10^{4.8}-10^{5.0}$ solar mass, Infrared data from WISE and 2MASS were used to identify and classify the YSO population associated with ongoing star formation activity within the molecular clouds. Moving away from the H II region, there is an age/class gradient consistent with sequential star formation. The infrared and molecular line data were combined to estimate the star formation efficiency (SFE) of the entire cloud as well as the SFE for various sub regions of the cloud.

• 천문학회보
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• 제45권1호
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• pp.50.4-51
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• 2020

We report our discovery of Raman-scattered He II λ6545 feature in young planetary nebulae NGC 6886 and NGC 6881 which indicates the existence of atomic hydrogen components. Considering sharply increasing cross-section of hydrogen atom near the resonance, Raman-scattered He II features are a useful diagnostic tool to investigate the distribution and kinematics of H I region in planetary nebulae. The high-resolution spectroscopic observation was carried out using BOES installed on the 1.8 m telescope of BOAO. We estimate the column density of H I region and its expansion velocity using our grid-based Monte-Carlo radiative transfer code. We assume that the H I region is uniformly distributed in spherical shell geometry with an opening angle and expands with constant speed. Our best-fit model is shown with the column density NHI = 3 × 1020 cm-2 and expansion speed vexp = 25 km s-1 with the opening angle ~ 25° for NGC 6886, and NHI = 4 × 1020 cm-2 and vexp = 30 km s-1 with the opening angle ~ 35° for NGC 6881. We present brief discussions on the late-stage of evolution of stars with mass > 3 M⊙.

• 대한화학회지
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• 제30권5호
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• pp.456-464
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• 1986

branched poly(ethylene imine) (BPEI)와 2가 전이금속인 Fe(II), Co(II), Ni(II) 및 Cu(II)간의 착물생성을 가시선 흡수 및 30${\circ}$, 0.1M KCl수용액 중에서 pH적정법으로 연구하였다. M(II)-BPEI착물의 안정도 상수는 M(II)-BPEI착물의 안정도 상수는 Gergor등에 의해 수정된 Bjerrum법으로 계산하였다. M(II)-BPEI착물의 생성 곡선으로 부터 ethylene imine group이 Fe(II)이온에 네자리, Co(II), Ni(II) 및 Cu(II) 이온에 각각 두 자리 배위된 착물이 생성됨을 알 수 있었다. Cu(II)-BPEI착물의 경우 pH 3.4~3.8을 기준으로 산성도가 감소 또는 증가함에 따라 최대 흡광도(${\lambda}_{max}$)는 장파장 쪽으로 이동하고, 흡광도는 pH증가에 따라 감소하였다. 총괄 안정도 상수(log $K_2$)는 Co(II) < Cu(II) < Ni(II) < Fe(II)순으로 증가하였다.

• 천문학회보
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• 제41권2호
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• pp.56.1-56.1
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• 2016

A low-mass star-forming region, L1251B, is an excellent example of a small and nearby group of protostellar objects. L1251B has been mapped spectroscopically with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. IRS has provided mid-IR emission lines (e.g., [Fe II], [Ne II], and ro-vibrational H2) and absorption features of CO2 and H2O ice in studying the physical state of the ionized gas and the material residing in the circumstellar environments. We will present the distribution of outflows and ice components in L1251B.

• 대한기계학회논문집B
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• 제30권9호
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• pp.882-890
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• 2006

The present study investigates the pressure drop characteristics in rotating two-pass ducts. The duct has an aspect ratio (W/H) of 0.5 and a hydraulic diameter $(D_h)$ of 26.67mm. Rib turbulators are attached parallel in the four different arrangements on the leading and trailing surfaces of the test ducts. The ribs have a rectangular cross section of $2m(e){\times}3mm(w)$ and an attack angle of $70^{\circ}C$. The pitch-to-rib height ratio (p/e) is 7.5, and the rib height-to-hydraulic diameter ratio $(e/D_h)$ is 0.075. The results show that the highest pressure drop among each region appears in the turning region for the stationary case, but appears in the upstream region of the second pass for the rotating case. Effects of parallel rib arrangements are almost the same in the first pass for the stationary and rotating cases. In the second pass, however, heat transfer and pressure drop are high for the cases with parallel NN or PP type ribs in the stationary ducts. In the rotating ducts, they are high for the cases with parallel NN or PN type ribs.

• 천문학회보
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• 제40권1호
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• pp.83.4-84
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• 2015

We report that a strong downflow event caused three-minute oscillations in the solar atmosphere. Our observations were carried out by using the Fast Imaging Solar Spectrograph (FISS) of the 1.6 meter New Solar Telescope (NST) and the Interface Region Imaging Spectrograph (IRIS). Our main findings are as follows: (1) The strong downflow was seen at the $H{\alpha}$ absorption line at first, and then appeared at the Si IV and C II emission lines. It seems that the characteristics of the downflow are consistent with a coronal rain event. (2) After the event, oscillations of velocity were identified in the chromospheric lines and transition region lines. (3) The amplitudes of oscillations were 2km/s at Mg II line and 3km/s at C II and Si IV lines and decreased with time. (4) The period of the oscillation was 2.67 minutes at first, but gradually increased with time. Our findings are in agreement with Chae & Goode (2015)'s theory that of acoustic waves generated by a disturbance in a gravitationally-stratified medium.

• 복식문화연구
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• 제13권2호
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• pp.248-254
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• 2005

In this study, wool fabric specimens were pre-mordanted using Sn, Al, Cu, Cr, and Fe, and subsequently dyed using cochineal, maintaining the pH of the dye bath constant using pH buffer solutions of 4, 5, 6, 7, and 8. In the case of wool fabric specimen, regardless of the type of mordanting agents, peak dye-uptake amount was obtained at the acidic region, pH 4, and above pH 6, the dye-uptake amount decreased remarkably. Differing from the cotton fabric case, the dyed wool fabric specimen exhibited red shade even in the case of non-mordanting, at the region of pH values of 4 and 5. It is presumed that in the acidic dye bath the effect of cationic amine group present in the structure of wool fiber molecules took place. The amount of color difference, among the mordanting agents, due to the increase of pH value, was highest for the Fe mordanting case. It seems, therefore, that the Fe mordanting is affected most by the pH value.

• 천문학회지
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• 제34권3호
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• pp.167-179
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• 2001

A molecular line survey towards the UC H II region G34.3+0.15 from 155.3 to 165.3GHz has been conducted with the TRAO 14-m radio telescope. Combined with our previous observations from 84.7 to 115.6GHz and 123.5 to 155.3GHz (Paper I), the spectral coverage of this survey in G34.3+0.15 now runs from 85 to 165 GHz. From these latest observations, a total of 18 lines from 6 species were detected. These include four new lines corresponding to ${\Delta}$J = 0, ${\Delta}$K = 1 transitions of the $CH_3OH$ E-type species, and two new lines corresponding to transitions from $SO_2$ and $HC_3N$. These 6 new lines are $CH_3OH$[1(1) - 1(0)E], $CH_3OH$[2(1) - 2(0)E], $CH_3OH$[3(1) - 3(0)E], $CH_3OH$[4(1) - 4(0)E], $SO_2$[14(1, 13) -14(0, 14)] and $HC_3N$[18 -17]. We applied a rotation diagram analysis to derive rotation temperatures and column densities from the methanol transitions detected, and combined with NRAO 12-m data from Slysh et al. 1999. Applying a two-component fit, we find a cold component with temperature 13-16K and column density $3.3-3.4 {\times} 10^{14} cm^{-2}$, and a hot component with temperature 64 - 83K and column density $9.3{\times}10^{14} - 9.7 {\times} 10^{14} cm^{-2}$. On the other hand, applying just a one-component fit yields temperatures in the 47 -62 K range and column densities from $7.5-1.1 {\times} 10^{15} cm^{-2}$.

• Journal of Astronomy and Space Sciences
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• 제18권1호
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• pp.33-42
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• 2001

이 논문에서는 Cerro Tololo Inter-American Observatory의 1.5미터 망원경에 설치된 에셸 분광기로부터 얻은 나비형 행성상 성운 M2-9의 분광 자료에 나타나는 6545 ${\AA}$의 방출선이 He II n = 6 -> n = 2 천이의 방출선이 수소 원자에 라만 산란되어 형성됨을 제안한다. 또한, 이 천체에서 He II의 방출선인 6560 ${\AA}$ (n = 6 -> n = 4)와 6527 ${\AA}$( n = 12 -> n = 5)이 분광 자료에 나타나지 않는다는 사실을 He II 방출선 지역이 뜨거운 백색 왜성 근처에서 형성되며, 광학적으로 두꺼운 성분에 쉽게 가려질 수 있지만, 증성 수소에 의한 라만 산란은 더 넓은 지역에서 형성되어 관측자 시선에 들어올 수 있음을 의미한다. 우리는 과이온화 모델을 사용하여, He II방출선 지역의 크기를 계한하였다. 이 계산의 결과로부터 우리는 중심별의 온도가 적어도 $10^5K$보다 더 뜨겁고, He II방출선 지역을 가리는 불투명한 성분의 크기가 $10^{16}cm$보다 크다고 추정한다. 이 크기는 M2-9까지 거리를 1 kpc으로 잡았을 때에 각거리로 1"로서, 허블 우주 망원경으로부터 알려진 적도면의 큰 소광을 일으키는 지역의 크기와 대체적으로 일치한다.