• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 1998년도 한국우주과학회보 제7권1호
• /
• pp.52.1-52
• /
• 1998

No Abstract.See Full-text

• 한국자동차공학회논문집
• /
• 제15권6호
• /
• pp.102-107
• /
• 2007

A fast response $CO_2$ ($fCO_2$) analyzer for real-time measurement of carbon dioxide concentration during transient states of internal combustion engines has been developed. This analyzer uses non-dispersive infrared absorption (NDIR) technique for measuring $CO_2$ concentration and Kalman filter for removing noise components from output signals. The analyzer has good linearity, repeatability and drift with a response time of 11 ms; it is sufficiently fast to detect $CO_2$ concentration during transient states of internal combustion engines. The $fCO_2$ analyzer was used to measure transient $CO_2$ concentration of exhaust gas of the SI engine with a standard gas analyzer, and the signal of the $fCO_2$ analyzer was compared to that of the standard gas analyzer. The two concentrations were well matched during the steady state, and the $fCO_2$ analyzer could measure the variations of $CO_2$ concentration during the transient state.

• 한국근적외분광분석학회:학술대회논문집
• /
• 한국근적외분광분석학회 2001년도 NIR-2001
• /
• pp.1518-1518
• /
• 2001

In the area of the destruction-free NIR analysis of fruit and vegetables development has not yet progressed as far as in grain and similar products. One reason for that is, that in contrast to grains, in fruit and vegetables water appears as the outstanding main-component making up typically 80% by weight of the fruit. Of the M absorption spectrum of pure water the bands at 1450, 970 and 760 nm are the first, second and third overtones respectively of O-H stretch while those at 1940 and 1190 are combination bands involving O-H stretch and O-H bend. The choice of band for spectrometry is governed by considerations of sensitivity and selectivity. The overtone bands are satisfactory for use in moisture measurements from 0 to 4 % depending on path length. Measurements in fruits and vegetables at wavelength areas that are also important for the determination of carbohydrates (sucrose, glucose, fructose) often lead to total absorption in the presence of significant water even if short path lengths are possible. In this work model systems are used containing different carbohydrates in solvents like heavy water (D$_2$O) or dimethylsulfoxide (DMSO) that do not contain O-H functional groups.

• Journal of Astronomy and Space Sciences
• /
• 제15권1호
• /
• pp.151-162
• /
• 1998

Infrared absorption spectra of 9 bulk samples and 3 acid residues of meteorites were obtained in the mid-infrared region ($4000~400cm^{-1}$). From the know composition of meteorites studied, the possible absorption modes were investigated. Most bands of bulk samples occur in the region below $1200cm^{-1}$ and they are due to metallic oxides and silicates. The spectra of each group can be distinguished by its own characteristic bands. Acid residues show very distinct features from their bulk samples, and absorp-tion bands due to organic compounds are not evident in their spectra. Quantiative analyses for two carbonaceous (Allende CV3 and Murchison CM2) and one ordinary (Carraweena L3.9) chondrites were performed for the presence of fullerene ($C_{60}$) in the meteorites. We calculated the concentration of $C_{60}$ in the acid residues by curve-fitting the spectra with Gaussian functions. The upper limit of $C_{60}$ concentration in these meteorites appears to be less than an order of a few hundred ppm.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
• /
• pp.301-304
• /
• 2006

For the purpose of investigating the contributions of various gases to climate change, the thermal radiation associated with greenhouse gases are extracted from AIRS (Atmospheric Infrared Sounder) infrared radiances over the tropical pacific region. AIRS instrument which was launched on the EOS-Aqua satellite in May 2002 covers the spectral range from 650 cm-1 to 2700 cm-1 with a spectral resolution of between 0.4 cm-1 and 1 cm-1. In order to extract the thermal radiation absorbed by individual gases, the interfering background radiances at the top of the atmosphere are simulated using the radiative transfer code MODTRAN (MODerate spectral resolution atmospheric TRANsmittance). The simulations incorporated the temperature and water vapor profiles taken from NCEP (National Centers for Environmental Prediction) reanalyses. The differences between the simulated background radiance and AIRS-measured radiance result in the absorption of upward longwave radiation by atmospheric gases (i.e. greenhouse effect). The extracted absorption bands of individual gases will allow us to quantify the radiative forcing of individual greenhouse gases and thus those data will be useful for climate change studies and for the validation of radiative transfer codes used in general circulation models.

• 한국세라믹학회지
• /
• 제40권8호
• /
• pp.746-750
• /
• 2003

Czochralski법을 이용하여 Er$_2$O$_3$가 첨가된 near stoichiometric조성의 LiNbO$_3$ 단결정을 Z-축의 방향으로 직경 15~20mm, 길이 25-30 mm의 크기로 성장시켰다. X-Ray Diffractometer (XRD)을 이용하여 격자상수를 조사하였고, Fourier Transform-Infrared Spectrophotometer (FT-IR)을 통하여 흡수밴드를 관찰하였다. 또한 Electron Probe Micro Analysis (EPMA)를 이용하여 결정 내에 Er의 분포를 확인하였다.

• 대한기계학회논문집B
• /
• 제22권3호
• /
• pp.399-407
• /
• 1998

The infrared reflection coatings with pigment can be used to protect the surfaces of combustible materials exposed to fire. To obtain high reflectivities in the infrared range (0.5-10.mu.m) important to fire, several dielectric pigments, such as titanium dioxide, iron oxide, and silicon, can be synthesized to polymer coatings. The theoretical analysis shows that the coating design with particles diameter in the 1.5 to 2.5.mu.m range and volume fraction in the 0.1 to 0.2 range is estimated to be optimal. In the analysis of the radiation, the dependent scattering, absorption by polymeric binder, and the internal interface reflection are considered. In addition, the temperature distribution in the semi-transparent coating layer and an opaque substrate (PMMA) is also presented.

• 약학회지
• /
• 제49권2호
• /
• pp.115-121
• /
• 2005

In this study, the performance of a portable NIR system and a FT NIR spectrometer were compared to determine water content of hairless mouse skin. The stratum corneum parts wer e separated from the epidermal tissues by trypsin solution. NIR diffuse reflectance spectra of hairless mouse skin were acquired using a fiber optic probe. In the near infrared, water molecules show two clear absorption bands at 1450 nm from first overtone of O-H stretching and 1940 nm from the combination involving O-H stretching and O-H deformation. It was found that the variations of O-H absorption band according to water content. Partial least squares regression (PLSR) was applied to develop a calibration model. The PLS model showed a good correlation between NIR predicted value and the absolute water content of separated hairless mouse skin, in vitro. For both the portable and the FT NIR spectrometer, These studies showed the possibility of a rapid and nondestructive skin moisture measurement using NIR spectroscopy. The portable NIR spectrometer with a photodiode arrays-microsensor could be more rapidly applied for the determination of water content with comparable accuracy with the performance of a FT spectrometer .

• 세라미스트
• /
• 제10권3호
• /
• pp.86-90
• /
• 2007

Novel photochromic oxide glasses are presented in this section. These glasses are based on phosphate formers containing both tungsten and antimony atoms. Exposure to visible continuous or pulsed laser beam results in an intense photochromic effect witch is shown to occur in the volume of the glass and results in a broad absorption band in the visible and near infrared. This effect was not identified to be related with a structural change and is assumed to be entirely electronic. A change in the absorption coefficient is observed in function of tungsten content, exposure time and increases with beam power. These glasses have been investigated regarding the possibility of holographic data storage using visible lasers sources. Changes in both refractive index and the absorption coefficient were measured using a holographic setup. The modulation of the optical constants is reversible by heat treatment.

• Bulletin of the Korean Chemical Society
• /
• 제35권3호
• /
• pp.851-857
• /
• 2014

Carotenoids, natural antenna pigments in photosynthesis share a symmetric backbone of conjugated polyenes. Contrary to the symmetric and almost planar geometries of carotenoids, excited state structure and dynamics of carotenoids are exceedingly complex. In this paper, recent infrared and visible transient absorption measurements and excitation dependent dynamics of 8'-apo-${\beta}$-caroten-8'-al and 7',7'-dicyano-7'-apo-${\beta}$-carotene will be reviewed. The recent visible transient absorption measurements of 8'-apo-${\beta}$-caroten-8'-al in polar and nonpolar solvents will also be introduced to emphasize the complex excited-state dynamics and unsolved problems in the $S_2$ and $S_1$ excited states.