• 한국대기환경학회지
• /
• 제23권1호
• /
• pp.97-109
• /
• 2007

Vertical distribution and optical properties of atmospheric aerosols above the Korean peninsula are quite important to estimate effects of aerosol on atmospheric environment and regional radiative forcing. For the first time in Korea, vertical microphysical properties of atmospheric aerosol obtained by inversion algorithm were analyzed based on optical data of multi-wavelength Raman lidar system developed by the Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST). Data collected on 14 June 2004 at Gwangju ($35.10^{\circ}N,\;126.53^{\circ}E$) and 27 May 2005 at Anmyeon island ($36.32^{\circ}N,\;126.19^{\circ}E$) were used as raw optical data for inversion algorithm. Siberian forest fire smoke and local originated haze were observed above and within the height of PBL, respectively on 14 June 2004 according to NOAA/Hysplit backstrajectory analysis. The inversion of lidar optical data resulted in particle effective radii around $0.31{\sim}0.33{\mu}m$, single scattering albedo between $0.964{\sim}0.977$ at 532 nm in PBL and effective radii of $0.27{\mu}m$ and single scattering albedo between $0.923{\sim}0.924$ above PBL. In the case on 27 May 2005, biomass burning from east China was a main source of aerosol plume. The inversion results of the data on 27 May 2005 were found to be particle effective radii between $0.23{\sim}0.24{\mu}m$, single scattering albedo around $0.924{\sim}0.929$ at 532 nm. Additionally, the inversion values were well matched with those of Sun/sky radiometer in measurement period.

• 한국고분자학회:학술대회논문집
• /
• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
• /
• pp.300-300
• /
• 2006

Nondestructive nanostructural analysis is indispensable in the development of nano-materials and nano-fabrication processes for use in nanotechnology applications. In this paper, we demonstrate for the first time a quantitative, nondestructive analysis of nanostructured thin films supported on substrates and their templated nanopores by using grazing incidence X-ray scattering and data analysis with a derived scattering theory. Our analysis disclosed that vertically oriented nanodomain cylinders had formed in 20-100 nm thick films supported on substrates consisting of a mixture of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) and PMMA homopolymer, and that the PMMA nanodomains were selectively etched out by ultraviolet light exposure and a subsequent rinse with acetic acid, resulting in a structure consisting of hexagonally packed cylindrical nanopores.

• 한국수산과학회지
• /
• 제43권4호
• /
• pp.380-385
• /
• 2010

Several theoretical acoustic scattering models were applied to estimate the target strength (TS) for assessing the biomass of zooplankton, to overcome the difficulty of direct measurements. Acoustical scattering characteristics of copepods were estimated using three theoretical models, and the application of the models was evaluated for four frequencies of a scientific echo sounder. The scattering directivity by the body shapes of copepods at 200 kHz and 420 kHz was significantly affected by TS patterns. Averaged TS, however, were similar at higher frequencies. Consequently, a low frequency model, such as a truncated fluid sphere model, provides a good acoustical biomass estimation. The regressions of TS and 30 logL were < $TS_{200\;kHz}$ >= 30logL-118.4 ($R^2=0.716$) and < $TS_{420 kHz}$ > =30 logL-108.8 ($R^2=0.758$), respectively.

• 대한전자공학회논문지TC
• /
• 제40권8호
• /
• pp.301-306
• /
• 2003

본 논문에서는 RBF Network를 이용한 새로운 수신기법을 MIMO 환경에서 제안한다. 그리고, 제안된 수신기의 성능을 Rich-scattering 페이딩 채널에서의 모의 실험을 통해 검증한다. 모의 실험 결과를 통해 제안된 수신기가 MLD와 유사한 성능을 나타내고, VBLAST-ZF와 VBLAST-MMSE보다 우수한 성능을 나타냄을 확인하였다. 그리고, 다양한 송수신 안테나의 개수 및 변조 기법에 따른 RBF 개수가 성능에 미치는 영향을 조사하였으며, 제안된 수신기의 성능을 RBF 중심값의 초기화 율에 따라 확인하였다.

• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 2008년도 High Temperature Superconductivity Vol.XVIII
• /
• pp.41-41
• /
• 2008

• Macromolecular Research
• /
• 제14권1호
• /
• pp.45-51
• /
• 2006

We conducted simultaneous, small-angle, X-ray scattering/differential scanning calorimetry (SAXS/DSC) and simultaneous, wide-angle, X-ray scattering (WAXS)/DSC measurements for a polymer blend of poly($\varepsilon$-caprolactone)/poly(ethylene glycol)(PCL/PEG). The time-dependent SAXS/DSC and WAXS/DSC results, measured while the system was quenched below the melting temperature of PCL from a melting state, revealed the competitive behavior between liquid-liquid phase separation and crystallization in the polymer blend. The time-dependent structural evolution extracted from the SAXS/WAXS/DSC results can be characterized by the following four stages in the PCL crystallization process: the induction (I), nucleation (II), growth (III), and late (IV) stages. The influence of the liquid-liquid phase separation on the crystallization of PCL was also observed by phase-contrast microscope and polarized microscope with 1/4$\lambda$ compensator.

• E2M - 전기 전자와 첨단 소재
• /
• 제16권9호
• /
• pp.62.3-63
• /
• 2003

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2005년도 제28회 학술발표회 초록집
• /
• pp.39-39
• /
• 2005

• Biomedical Engineering Letters
• /
• 제8권4호
• /
• pp.383-392
• /
• 2018

For prompt gamma ray imaging for biomedical applications and environmental radiation monitoring, we propose herein a multiple-scattering Compton camera (MSCC). MSCC consists of three or more semiconductor layers with good energy resolution, and has potential for simultaneous detection and differentiation of multiple radio-isotopes based on the measured energies, as well as three-dimensional (3D) imaging of the radio-isotope distribution. In this study, we developed an analytic simulator and a 3D image generator for a MSCC, including the physical models of the radiation source emission and detection processes that can be utilized for geometry and performance prediction prior to the construction of a real system. The analytic simulator for a MSCC records coincidence detections of successive interactions in multiple detector layers. In the successive interaction processes, the emission direction of the incident gamma ray, the scattering angle, and the changed traveling path after the Compton scattering interaction in each detector, were determined by a conical surface uniform random number generator (RNG), and by a Klein-Nishina RNG. The 3D image generator has two functions: the recovery of the initial source energy spectrum and the 3D spatial distribution of the source. We evaluated the analytic simulator and image generator with two different energetic point radiation sources (Cs-137 and Co-60) and with an MSCC comprising three detector layers. The recovered initial energies of the incident radiations were well differentiated from the generated MSCC events. Correspondingly, we could obtain a multi-tracer image that combined the two differentiated images. The developed analytic simulator in this study emulated the randomness of the detection process of a multiple-scattering Compton camera, including the inherent degradation factors of the detectors, such as the limited spatial and energy resolutions. The Doppler-broadening effect owing to the momentum distribution of electrons in Compton scattering was not considered in the detection process because most interested isotopes for biomedical and environmental applications have high energies that are less sensitive to Doppler broadening. The analytic simulator and image generator for MSCC can be utilized to determine the optimal geometrical parameters, such as the distances between detectors and detector size, thus affecting the imaging performance of the Compton camera prior to the development of a real system.

• 한국고분자학회:학술대회논문집
• /
• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
• /
• pp.301-301
• /
• 2006

The physical properties of well-defined star-shape polystyrenes with high number of arms (6 to 57 arms) in good and theta solvents were studied using synchrotron X-ray scattering. The scattering profiles for multi-armed polystyrenes shown the molecular shape is changed according to increasing of number of arm. From various parameters which were obtained from scattering profiles, the molecular shape was determined more detail. As results, the molecular shape was changed from a fuzzy-ellipsoid for 6-armed PS to a fuzzy-sphere sphere for 57-armed PS according to increasing of number of arm.