• Journal of Pharmaceutical Investigation
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• v.14 no.4
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• pp.183-188
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• 1984

The interactions of FD & C Red No.3 (erythrosine) in 1 or 2% concentrations with various types of pharmaceutical gelatins were studied. In visible region spectroscopy type A gelatin showed 6 nm bathochromic shift in ${\lambda}_{max}$ of erythrosine, but no shifts were observed in other gelatins. Various results were obtained in the decrease of absorbance from 0.06 to 0.25. In dissolution study, the gelatin that showed the greatest spectral change exhibited the worst profile. From above results, it is concluded that erythrosine interacted to the greatest extent with type A gelatin and in the case of type B gelatin the degree of the interaction in different according to their specifications.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.208-209
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• 2003

We have developed a practical Brillouin active fiber ring sensor of length less than 20m, by employing an optical amplifier to compensate for most of the connection losses in the ring. The loss reduction brings the standard Brillouin threshold from 21 down to 0-0.1 through the enhancement of the finesse of the ring. However, in the course of our experiments, some level of temporal instability and chaotic behavior in the backscattered Stokes intensity and also in its spectral line shift were consistently observed. (omitted)

• Journal of Magnetics
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• v.2 no.4
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• pp.138-142
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• 1997

The magnetic and magneto-optical properties of Ni/Pt multilayers exhibiting square Kerr hysterisis loops at room temperature were studied. Squared polar Kerr hysterisis loops at room temperature in Ni/Pt multilayer thin films were obtained for the samples prepared by sequential dc magnetron sputter deposition of nickel and platinum with tNi=13-21$\AA$ and tPt=3.5-7.5$\AA$. The coercivity of these multilayers was in the range of 400-1100 Oe. The saturation magnetization was found to show an inverse dependence on nickel sublyaer thickness. About a monolayer of Ni at interface was observed to behave less magnetically than the interior Ni atoms. The polar Kerr rotation exhibited an increasing trend with decreasing wavelength in the spectral range of 7000-4000 $\AA$. The maximum of polar Kerr rotation was found to shift to higher wavelengths with increase in nickel sublayer thickness.

• Journal of Magnetics
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• v.14 no.2
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• pp.86-89
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• 2009

Structural and magnetic properties of polycrystalline $CaFe_2O_4$ prepared by the solid state reaction method were studied using powder X-ray diffraction (XRD) and $M{\ddot{o}}ssbauer$ spectroscopy. The structure of $CaFe_2O_4$ belongs to an orthorhombic system (space group: Pnma) with the lattice parameters $a=9.2373\;{\AA}$, $b=3.0237\;{\AA}$, and $c=10.7124\;{\AA}$. Results of structural refinement indicate, however, that there are two slightly different iron sites in the sample. The $M{\ddot{o}}ssbauer$ spectrum at 4.2 K shows a hyperfine sextet with a hyperfine magnetic field and an isomer shift of 47.3 T and 0.36 mm/s, respectively. An examination of the spectrum revealed that the line widths of the spectral lines were not uniform. The degree of asymmetric line broadening decreases with increasing temperature, suggesting that the difference in the degree of crystalline distortions between two $FeO_6$ octahedra is eliminated as the temperature rises.

• Journal of Integrative Natural Science
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• v.3 no.1
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• pp.24-27
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• 2010

Multi-functionalized rugate porous silicon (PSi) for biosensor was developed by hydrosilylation with silole and its further reaction with biotin groups. PSi was generated by an electrochemical etching of silicon wafer in aqueous ethanolic HF solution PSi prepared by using etching conditions showed that many sharp spectral lines can be obtained in the optical reflectivity spectrum. 1,1-hydrovinyl-2,3,4,5-tetraphenylsilole was obtained from the reaction of 1,1-dilithio-2,3,4,5-tetraphenyl-1,3-butadiene with dichlorovinylsilane. Multi-functionalized PSi with silole and biotin groups was characterized by UV-vis absorption spectroscopy, Ocean optics 2000 spectrometer, and fluorescence spectroscopy. Optical characteristics such as reflectivity and photoluminescence (PL) were observed. An increase of the reflection wavelength in the reflectivity spectrum by 20 nm was observed, indicative of a change in refractive indices induced by hydrosilylation of the silole and biotin groups to the rugate PSi. This red-shift was attributed to the replacement of some of the Si-H group of fresh rugate PSi with silole and biotin group.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.113-116
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• 2000

Phase noise of oscillator gives the performance degradation significantly when a high carrier frequency and low transmission rate are used. The BER(Bit Error Rates) degradation of QPSK(Quadrature Phase Shift Keying) transmission is analyzed with the oscillator phase noise level specified in downstream physical interface of LMDS(Local Multipoint Distribution Services) which is described in DAVIC(Digital Audio Visual Council). The model used for the phase noise is a power-law model. We also investigated the effects of the various transmission rates on system performance. For the transmission rate below 0.5 Mbps, the BER performance is severely degraded and we verified that the transmission rate, 20 Mbps, is adequate for the downstream of LMDS systems.

• Bulletin of the Korean Chemical Society
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• v.23 no.8
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• pp.1111-1115
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• 2002

The photoluminescence of calixarene crystals has been studied as functions of temperature, time, and concentration. The vibronic bands shift to longer wavelength and become significantly sharper as temperature decreases. The experimental results r eveal that the structural transformation occur during the annealing process. Time-resolved spectra of calixarene at 12 K are monitored. Spectral features, which demonstrate characteristic of energy transfer processes, are not observed. The depopulation of excited state density is mainly controlled by unimolecular decay process dominating other decay processes. The lifetime was found to be 2.6 $\pm$ 0.1 ns. For the case of calixarene mixed with naphthalene, the fluorescence spectrum shows that the band centered at 340 nm lies 2840 $cm^{-1}$ below the relatively broad 310 nm band found for calixarene crystals. The spectra also exhibit that the emission intensity increases with increasing calixarene concentration. The results are evident that the calixarene emission is quenched by the naphthalene. Phosphorescence of calixarene mixed with naphthalene crystals is observed to determine whether the emission is due to naphthalene. The phosphorescence peaks were compared with the ground-state vibrational frequencies of naphthalene and found to be in good agreement. The results indicate that inter-molecular energy transfer occurs between calixarene and naphthalene.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.27-27
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• 2013

Development of bolometer array and camera at millimeter and submillimeter wavelengths plays an important role for detecting submillimeter galaxies (SMGs) which appear to be very bright at the submillimeter and millimeter wavelengths. These SMGs, luminous infrared galaxies detected at mm/submm wavelengths seem to be progenitors of present-day massive galaxies and account for their considerable contributions to the light from the early universe and their expected high star formation rates (SFRs) if there is a close link between the SMG phenomena and the star formation activities and the interstellar dust in galaxies is mainly heated by the star light. In this talk, we review assembly of SMGs compiled with observations using the bolometer arrays and cameras and investigate their spectral energy distribution fits including the data at other wavelengths which trace the photometric properties and the red-shift distribution of galaxies. We find that these bright SMGs significantly contribute to the cosmic star formation rate density at red-shifts of 2-3 (about 8 %) for the spatial distribution of these galaxies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.9
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• pp.833-837
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• 2003

The spectral and temporal characteristics of a V-groove AIGaAs-GaAs quantum wire (QWR) laser were investigated with varying the cavity length. At cavity lengths shorter than 300 ${\mu}{\textrm}{m}$, a discrete shift in tile wavelength occurred from the n=1 to the n=2 subband due to the increased cavity losses. Utilizing this characteristic, ultrafast lasing characteristics at each subband were investigated by tile gain switching method.

• ETRI Journal
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• v.26 no.1
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• pp.13-20
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• 2004

We propose a new optical code division multiple access (OCDMA) scheme for reducing multiple access interference (MAI) and enhancing performance for optical subscriber access networks using modified pseudorandom noise (PN)-coded fiber Bragg gratings with bipolar OCDMA decoders. Through the bipolar OCDMA decoder and the modified PN codes, MAI among users is effectively depressed. As the data are encoded either by a unipolar signature sequence of the modified PN code or its complement according to whether the data bit is 1 or 0, the bit error ratio (BER) can be more improved with the same signal to interference plus noise ratio over the conventional on-off shift keying-based OCDMA system. We prove by numerical analysis that the BER of the proposed bipolar OCDMA system is better than the conventional unipolar OCDMA system. We also analyze the spectral power distortion effects of the broadband light source.