• 천문학회보
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• 제44권1호
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• pp.42.3-42.3
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• 2019

The high-resolution near-infrared (NIR) spectroscopy can reveal the evidence of the accretion burst (e.g., the broadened absorption features produced by the Keplerian disk motion) although the moment of the outburst was not caught. The embedded protostar IRAS 16316-1540 observed with the Immersion Grating Infrared Spectrograph (IGRINS, $R={\Delta}{\lambda}/{\lambda}{\sim}45000$) shows the broad absorption features in atomic and CO transitions, as seen in FU Orionis objects (FUors), indicative of an outburst event. We examine whether the spectra of IRAS 16316-1540 arise from the rotating inner hot gaseous disk. Using the IGRINS spectral library, we show that the line profiles of IRAS 16316-1540 are more consistent with an M1.5 V template spectrum convolved with a disk rotation profile than the protostellar photosphere absorption features with a high stellar rotation velocity. We also note that the absorption features deviated from the expected line profile of the accretion disk model can be explained by a turbulence motion generated in the disk atmosphere. From previous observations that show the complex environment and the misaligned outflow axes in IRAS 16316-1540, we suggest that an impact of infalling clumpy envelope material against the disk induces the disk precession, causing the accretion burst from the inner disk to the protostar.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3879-3882
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• 2012

• 한국결정학회:학술대회논문집
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• 한국결정학회 2001년도 Korean Crystallographic Association 2001 Fall Meeting:Tutorial Course:Applicantions of Syn
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• pp.105-148
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• 2001

• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 제13회 정기총회 및 2002년도 동계학술발표회
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• pp.78-79
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• 2002

• 한국광학회지
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• 제17권4호
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• pp.305-311
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• 2006

우리는 포화흡수 분광에서 이광자 결맞음 효과를 고려한 7준위 원자 모델을 제안하고 이를 이용하여 Nakayama이론으로 설명할 수 없었던 레이저의 세기에 따른 스펙트럼의 변화와 일부 교차공진선에서 Nakayama이론과의 불일치 현상을 설명하였다. 우리는 Zeeman 부준위에서 펌프광과 조사광의 편광이 $\pi-\pi$일 때를 모두 고려하여 상준위 2개 하준위 5개로 구성된 7준위의 모델을 만들었고, $^{85}$Rb원자의 5S$_{1/2}$ - 5P$_{1/2}$ 전이선에 대하여 4준위 Nakayama이론과 7준위 원자 모델을 비교하였다. 또한 레이저의 세기에 따른 포화흡수 분광 스펙트럼과 7준위 원자모델로 계산한 이론결과가 잘 일치함을 보였다.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3771-3776
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• 2010

The dynamics of the $CN^-$-ligated ferric cytochrome c (CytcCN) in $D_2O$ at 283 K following Q-band photoexcitation at 575 nm was observed using femtosecond time-resolved vibrational spectroscopy. The equilibrium vibrational spectrum of the CN stretching mode of CytcCN shows two overlapping bands: one main band (82%) at $2122\;cm^{-1}$ with $23\;cm^{-1}$ full width at half maximum (fwhm) and the other band (18%) at $2116\;cm^{-1}$ with $7\;cm^{-1}$ fwhm. The time-resolved spectra show bleaching of the CN fundamental mode of CytcCN and two absorption features at lower energies. The bleach signal and both absorption features are all formed within the time resolution of the experiment (< 200 fs) and decay with a life time of 1.9 ps. One transient absorption feature, appearing immediately red to the bleach signal, results from the thermal excitation of low-frequency modes of the heme that anharmonically couple to the CN fundamental mode, thereby shifting the CN mode to lower energies. The shift of the CN mode decays with a lifetime of 2 ps, equivalent to the time scale for vibrational cooling of the low-frequency heme modes. The other transient absorption feature, which is 3.3 times weaker than the bleach signal and shifted $27\;cm^{-1}$ toward lower energies, is attributed to the CN mode in an electronically excited state where the CN bond is weakened with a lowered extinction coefficient. These observations suggest that photoexcited CytcCN mainly undergoes ultrafast radiationless relaxation, causing photo-deligation of $CN^-$ from CytcCN highly inefficient. As also observed in $CN^-$-ligated myoglobin, inefficient ligand photodissociation might be a general property of $CN^-$-ligated ferric hemes.

• 한국항공우주학회지
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• 제49권11호
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• pp.893-900
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• 2021

본 연구에서는 산소의 흡수선을 검출하는 레이저 흡수 분광 시스템을 사용하여 좁은 시험 구간 내의 공기 밀도가 측정되었다. 13156.28과 13156.62 cm^-1에 존재하는 산소의 흡수선 한 쌍이 측정되었다. 높이 40 mm를 가지는 기체 챔버가 좁은 시험 구간으로 사용되었다. 레이저 진행 경로를 확장하여 흡수 세기를 증폭시키기 위해 삼각 나선 형태의 레이저 광경로가 기체 챔버 내에 구성되었다. 잘 알려진 로그 증폭기와 2차 증폭기를 사용하여 흡수선 신호를 전기적으로 증폭하였다. 로그 증폭기 이후 신호 포화 방지 및 노이즈 억제를 위해 AC 커플링이 적용되었다. 로그 증폭기 회로구성을 고려하여 출력 신호로부터 파수별 흡광도를 계산하는 과정이 소개되었다. 이론적으로 계산된 파수별 흡광도를 실험적으로 측정된 파수별 흡광도에 선 맞춤하여 공기의 밀도가 측정되었다. 부르돈 압력계를 사용하여 기체 챔버 내에 상온과 10~100 kPa 범위 내에서 다양한 압력을 가지는 시험 조건들이 만들어졌다. 삼각 나선 형태의 광경로 및 로그 증폭기를 사용한 흡수 신호 증폭을 통해, 16 %의 오차 이내에서 좁은 시험 구간의 공기 밀도가 측정될 수 있음이 확인되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.283-283
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• 2011

The n-doping effect by doping metal carbonate into an electron-injecting organic layer can improve the device performance by the balanced carrier injection because an electron ohmic contact between cathode and an electron-transporting layer, for example, a high current density, a high efficiency, a high luminance, and a low power consumption. In the study, first, we investigated an electron-ohmic property of electron-only device, which has a ITO/$Rb_2CO_3$-doped $C_{60}$/Al structure. Second, we examined the I-V-L characteristics of all-ohmic OLEDs, which are glass/ITO/$MoO_x$-doped NPB (25%, 5 nm)/NPB (63 nm)/$Alq_3$ (32 nm)/$Rb_2CO_3$-doped $C_{60}$(y%, 10 nm)/Al. The $MoO_x$doped NPB and $Rb_2CO_3$-doped fullerene layer were used as the hole-ohmic contact and electron-ohmic contact layer in all-ohmic OLEDs, respectively, Third, the electronic structure of the $Rb_2CO_3$-doped $C_{60}$-doped interfaces were investigated by analyzing photoemission properties, such as x-ray photoemission spectroscopy (XPS), Ultraviolet Photoemission spectroscopy (UPS), and Near-edge x-ray absorption fine structure (NEXAFS) spectroscopy, as a doping concentration at the interfaces of $Rb_2CO_3$-doped fullerene are changed. Finally, the correlation between the device performance in all ohmic devices and the interfacial property of the $Rb_2CO_3$-doped $C_{60}$ thin film was discussed with an energy band diagram.

• Journal of Photoscience
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• 제9권2호
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• pp.460-462
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• 2002

Absorption spectra of biological specimens in the soft X-ray region have been presented with special reference to the XANES (X-ray absorption Near Edge Structure) of constituent elements. Absorption spectrum in this wavelength region is characterized by the absorption edges from which elemental content could be derived. In addition, XANES has a characteristic profile for chemical environment around the element such as chemical bond. Using the specific absorption peak we can assign not only the chemical bond but also molecules having such a chemical bond. In the present paper, absorption spectrum of DNA was measured in the wavelength range from 1.5nm to 5nm. Spectrum of Chinese Hamster Ovary (CHO) cells was compared with the DNA spectrum. XANES were distinct at the K absorption edges of major elements, C, N and O. In the spectrum of the cells prominent peaks at the L absorption edge of minor element Ca were also detectable. XANES profiles in small local areas in a cell could also be measured in combination with X-ray microscopy. These give information about local chemical environment in a cell. XANES at the phosphorus K absorption edge in a human HeLa cell was successfully obtained corresponding to a sharp and intensive XANES peak of DNA.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.335-341
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• 2018

We report the catalytic effects of metal oxides on the $CO_2$ absorption rate in an aqueous potassium salt of ${\text\tiny{L}}-lysine-HCl$ using the vapor liquid equilibrium method. The best $CO_2$ absorption rate obtained through testing metal oxides in a highly concentrated potassium salt of amino acids (2.0 M) was identified using CuO. The recyclability of the metal oxides was tested over three cycles. The catalyst CuO was found to enhance the absorption rate of $CO_2$ by 61%. A possible mechanism was proposed based on NMR spectroscopy studies. Further, the effect of change in liquid absorbent viscosity on $CO_2$ absorption is discussed.