• Journal of the Optical Society of Korea
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• 제5권3호
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• pp.110-116
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• 2001

Recently observed dark resonance phenomena is solids are reviewed and discussed for potential applications to high-resolution coherence spectroscopy. in an inhomogeneously broadened system, a new type of high-resolution spectroscopy based on electromagnetically induced transparency is demonstrated.

• Journal of the Optical Society of Korea
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• 제15권1호
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• pp.103-108
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• 2011

Recently reported asynchronous-optical-sampling terahertz (THz) time-domain spectroscopy enables high-resolution spectroscopy due to a long time-delay window. However, a long-lasting tail signal following the main pulse is often measured in a time-domain waveform, resulting in spectral fluctuation above a background noise level on a high-resolution THz amplitude spectrum. Here, we adopt the wavelet power spectrum estimation technique (WPSET) to effectively remove the spectral fluctuation without sacrificing spectral features. Effectiveness of the WPSET is verified by investigating a transmission spectrum of water vapor.

• 천문학회보
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• 제39권2호
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• pp.93.2-93.2
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• 2014

Planetary nebulae (PN) are the last stages of evolution of intermediate mass (1-8 Msolar) stars. Their shapes are thought to result from interactions between the present-day, fast (emerging white dwarf) and previously ejected, slow (red giant) stellar winds. The observation of young, bright PN, NGC7027 and BD+30 3639, was made on July 7, 2014 using the 2.7m Harlan J. Smith telescope at the McDonald Observatory. IGRINS with high spatial (0.27") and high spectral ($7.5km\;s^{-1}$) resolution will provide more nebular lines and excitation/abundances to constrain the morphology and kinematics of the Nebula and the PDRs. Combined with other archival data (X-ray, 2MASS, WISE, Spitzer, Herschel) for PN, high-resolution IR spectroscopy will yield insight into poorly understood aspects of PN morphologies and the late stages of binary star evolution.

• 천문학논총
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• 제19권1호
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• pp.39-46
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• 2004

We have carried out the high-resolution spectroscopic observations of Titan using BOES (Bohyunsan Echelle Spectrometer) to establish a standard spectral atlas of Titan. The observations were made on November 3, 4, 16 and 17, 2003 using a 300 11m fiber optics with a spectral resolving power of 30,000. The spectral atlas will be served as a reference for the future spectroscopic researches of Titan and other planetary objects. We were able to confirm $CH_4$ absorption lines of the Kuiper bands, and find unidentified lines near $7500{\AA}$.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1194-1197
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• 2004

High temporal-resolution and accurate measurement of skin impedance locus provides useful data for the identification of the physiological/psychological changes and also the identification of acupuncture point. An impedance spectroscopy method using digitally constructed current waveform consisting of many frequency components (multiples of 1Hz) was reported3. The time resolution of the method depends on the lowest frequency used in the waveform construction, and therefore, the measurement would be faster if the lowest frequency is the higher. However, it was not clear that how many and how low frequencies must be used for the estimation of the skin impedance parameters from which the impedance locus can be drawn. This study shows the relationship between the estimation error of the impedance parameters and the frequency coverage of the spectroscopy. The results of this study are expected to serve as the reference of the frequency selection in the impedance spectroscopy.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3481-3484
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• 2012

• 천문학회보
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• 제41권1호
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• pp.59.4-60
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• 2016

One important aspect of the late stage stellar evolution is the mass loss processes, where a significant amount of stellar material will be returned to the interstellar space to be used for stars of the next generation. Raman scattered O VI and He II by atomic hydrogen in symbiotic stars and young planetary nebulae are found to be excellent tools to investigate the mass loss processes and estimate the mass loss rate. These features appear near hydrogen Balmer emission lines due to the huge cross section in the vicinity of Lyman resonance transitions. With the capability of high spectral resolution and broad spectral coverage, BOES is an ideal instrument to perform Raman spectroscopy of these objects. In this talk, a cursory overview of our research activities on Raman spectroscopy of symbiotics and PNe using the BOES is presented.

• 한국광학회지
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• 제19권5호
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• pp.370-375
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• 2008

본 논문에서 비동시성 광샘플링(asynchronous optical sampling; AOS) 방식을 이용하는 고속 고분해 테라헤르츠 시간영역 분광(terahertz time domain spectroscopy; THz-TDS)을 시연한다. 모터로 구동되는 선형 스테이지를 사용하지 않고, 약간 다른 반복 주파수를 갖는 두 대의 펨토초 레이저를 각각 테라헤르츠파 발생과 검출에 사용하여 고속으로 10 ns의 시간축 상의 신호를 획득하고 fast Fourier transformation(FFT)을 통하여 100 MHz의 주파수 분해능을 갖는 고분해 분광을 구현한다. Cross-correlation 방법에 의해 시간 분해능은 278 fs으로 측정되었다. 또한, 본 분광기를 이용하여 수증기의 투과 스펙트럼을 측정하고 흡수선들을 분석하였다.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1440-1448
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• 2014

Co(II)-tetrasulfonated phthalocyanine (CoTSP) is known to be aggregated to dimer at high concentration levels in water. A study on the aggregation of CoTSP using multivariate curve resolution analysis of the visible absorbance spectra over a concentration range of 30, 40 and 50 ${\mu}M$ in the presence of dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), acetonitrile (AN) and ethanol (EtOH) in the concentration range of 0 to 3.57 M is conducted. A hard modeling-based multivariate curve resolution method was applied to determine the dissociation constants of the CoTSP aggregates at various temperatures ranging from 25, 45 and $65^{\circ}C$ and in the presence of various co-solvents. Dissociation constant for aggregation was increased and then decrease by temperature and concentration of phthalocyanine, respectively. Utilizing the vant Hoff relation, the enthalpy and entropy of the dissociation equilibriums were calculated. For the dissociation of both aggregates, the enthalpy and entropy changes were positive and negative, respectively. Molecular dynamics simulation of cosolvent effect on CoTSP aggregation was done to confirm spectroscopy results. Results of radial distribution function (RDF), root mean square deviation (RMSD) and distance curves confirmed more effect of polar solvent to decrease monomer formation.

• 천문학회보
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• 제30권2호
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• pp.32.2-32.2
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• 2005