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121.
Kihong Son Haijo Jung Sang Hun Shin Hyun-Ho Lee Mi-Sook Kim Young Hoon Ji Kum Bae Kim 《Radiation measurements》2011,46(10):1117-1122
We aimed to evaluate the suitability of a glass dosimeter (GD) for high-energy photon and electron beams in experimental and clinical use, especially for radiation therapy. We examined the expanded dosimetric characteristics of GDs including dose linearity up to 500 Gy, uniformity among GD lots and for individual GDs, the angular dependence, and energy dependence of 4 therapeutic x-ray qualities. In addition, we measured the dosimetric features (dose linearity, uniformity, angular dependence, and energy dependence) of the GD for electron beams of 10 different electron energy qualities. All measurements with the exception of dose linearity for photon beam were performed in a water phantom. For high-energy photon beams, dose linearity has a linear relationship for a dose ranging from 1 to 500 Gy with the coefficient of determination; R2 of 0.998. The uniformity of each GD of dose measurements was within ±0.5% for four GD lots and within ±1.2% for 80 GDs. In terms of the effects of photon beam angle, lower absorbed doses of within 1.0% were observed between 60° and 105° than at 90°. The GD energy dependence of 4 photon beam energy qualities was within ±2.0%. On the other hand, the result of the dose linearity for high-energy electron beams showed well fitted regression line with the coefficient of determination; R2 of 0.999 between 6 and 20 MeV. The uniformity of GDs exposed to the nominal electron energies 6, 9, 12, 16, and 20 MeV was ±1.2%. In terms of the angular dependence to electron beams, absorbed doses were within 2.0% between 60° and 105° than at 90°. In evaluation of the energy dependence of the GD at nominal electron energies between 5 and 20 MeV, we obtained responses between 1.1% and 3.5% lower than that for a cobalt-60 beam. Our results show that GDs can be used as a detector for determining doses when a high-energy photon beam is used, and that it also has considerable potential for dose measurement of high-energy electron beam. 相似文献
122.
I.-H. Bae H. S. Moon S. Zaske C. Becher S. K. Kim S.-N. Park D.-H. Lee 《Applied physics. B, Lasers and optics》2011,103(2):311-319
We present a 532 nm-pumped singly-resonant cw optical parametric oscillator based on MgO-doped PPLN with a minimum threshold
pump power of 0.3 W. The OPO with a two-mirror standing-wave cavity is optimized by using a tunable diode laser on the path
of the resonant signal beam. The maximum output power is 200 mW at an idler wavelength near 1330 nm at a pump power of 2 W.
We report the degradation of the output power and beam characteristics at high pump power indicating a strong thermal lensing
in the crystal. The continuous tuning range of the OPO is measured to be 800 MHz which is close to 90% of the free spectral
range of the OPO cavity. 相似文献
123.
A single-mode fiber (SMF) acousto-optic tunable filter (AOTF) with a tuning range of more than 300 nm is demonstrated. The SMF used in the experiment has a ring of symmetric holes within the cladding, which causes a larger mode-index difference between the first and the second higher-order antisymmetric modes than those of a conventional SMF. As a result, the difference in beatlengths between the core mode and the higher-order modes is highly increased, which makes it possible for the SMF AOTF to exhibit a single resonance peak in the transmission spectrum over the wavelength range of 1.3-1.6 μm for given acoustic frequencies of 3.1-3.8 MHz. 相似文献
124.
M.?FouchierEmail author E.?Pargon L.?Azarnouche K.?Menguelti O.?Joubert T.?Cardolaccia Y.?C.?Bae 《Applied Physics A: Materials Science & Processing》2011,105(2):399-405
193 nm photoresists which are methacrylate-based polymers are very sensitive to vacuum ultra violet (VUV) light (100 nm<λ<200 nm) generated by plasmas used for pattern transfer technologies. Upon plasma treatment the physical properties of the
polymers can be deeply modified. To better understand the chemical changes involved, the absorption coefficient of a commercial
193 nm photoresist has been measured in the 120–280 nm wavelength range using a home built experimental set-up. The different
contributions to the absorption were identified by also measuring the spectra of model polymers and simpler polymer chains.
This knowledge was then used to identify the chemical changes in the photoresist upon heating up to 240°C. 相似文献
125.
Youngjin Bae 《Israel Journal of Mathematics》2014,204(1):417-430
We study the growth rate of a sequence which measures the uniform norm of the differential under the iterates of maps. On symplectically hyperbolic manifolds, we show that this sequence has at least linear growth for every non-identical symplectomorphisms which are symplectically isotopic to the identity. 相似文献
126.
Bo Hyun Kong Hyung Koun Cho Mi Yang Kim Rak Jun Choi Bae Kyun Kim 《Journal of Crystal Growth》2010,312(14):2128-2132
InGaN/GaN multiple quantum well-based blue light emitting diodes (LEDs) with different spacer layer structures were grown by metalorganic chemical vapor deposition. Fast-Fourier-transformed high-resolution transmission electron microscopy was used to determine the influence of the strain status in the spacer layer on Mg distribution and device performance. A comparison of the (1 1¯ 0 0) planar distance showed that the high-temperature grown InGaN layer in the spacer had a high level of stored strain. This led to the formation of a continuous facet contrast induced by Mg segregation in the p-layer, which was responsible for the deterioration of the electroluminescence performance of the LEDs. These results show that the delicate control of stored strain in nitride films is important for improving the device performance. 相似文献
127.
Jung‐Woo Bae Chang‐Ik Choi Choon‐Gon Jang Seok‐Yong Lee 《Biomedical chromatography : BMC》2011,25(11):1181-1188
A simple and sensitive liquid chromatography–electrospray ionization–tandem mass spectrometry (LC‐ESI‐MS/MS) technique was developed and validated for the determination of sibutramine and its N‐desmethyl metabolites (M1 and M2) in human plasma. After extraction with methyl t‐butyl ether, chromatographic separation of analytes in human plasma was performed using a reverse‐phase Luna C18 column with a mobile phase of acetonitrile–10 mm ammonium formate buffer (50:50, v/v) and quantified by ESI‐MS/MS detection in positive ion mode. The flow rate of the mobile phase was 200 μL/min and the retention times of sibutramine, M1, M2 and internal standard (chlorpheniramine) were 1.5, 1.4, 1.3 and 0.9 min, respectively. The calibration curves were linear over the range 0.05–20 ng/mL, for sibutramine, M1 and M2. The lower limit of quantification was 0.05 ng/mL using 500 μL of human plasma. The mean accuracy and the precision in the intra‐ and inter‐day validation for sibutramine, M1 and M2 were acceptable. This LC‐MS/MS method showed improved sensitivity and a short run time for the quantification of sibutramine and its two active metabolites in plasma. The validated method was successfully applied to a pharmacokinetic study in human. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
128.
Suk Yung OhYoung Chan Bae 《Fluid Phase Equilibria》2011,307(2):202-207
In our previous study [S.Y. Oh, Y.C. Bae, J. Phys. Chem. B 114 (2010) 8948-8953], we presented a new method to predict liquid-liquid equilibria in ternary simple liquid mixtures by using a combination of a thermodynamic model and molecular simulations. As a continuation of that effort, we extend our previously developed method to ternary polymer systems. In the simulations, we used the dummy atoms to calculate the pair interaction energy values between the polymer segments and the solvent molecules. Furthermore, a thermodynamic model scaling concept is introduced to consider the chain length dependence of the energy parameters. This method was applied to ternary mixtures incorporating low to high molecular weight polymers. The method presented here well described the experimental observations using one or no adjustable parameters. 相似文献
129.
Janet S. S. Wong Liang Hong Sung Chul Bae Steve Granick 《Journal of Polymer Science.Polymer Physics》2010,48(24):2582-2588
The surface forces apparatus has been combined with fluorescence recovery after photobleaching to measure translational diffusion of polymer confined between mica sheets. This article presents findings using polydimethylsiloxane with number‐average molecular weight Mn = 2200 g mol?1, the chains end‐labeled with soluble fluorescent dye. Melts with thickness 10 nm display a translational diffusion coefficient (D) with a bulk component and a slower component assigned to surface diffusion. Reduction of thickness to 1.8 nm causes mobility to split into two populations—an immobile fraction (immobile on the time scale of 30–60 min) and a mobile fraction who's D slow only weakly with diminishing film thickness. However, when load causes the confining mica sheets to flatten, D of the mobile fraction drops by up to an additional order of magnitude, depending on the local pressure that squeezes on the polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010 相似文献
130.
Jihoon Shin Ying Chang Thi Le Thanh Nguyen Seok Kyun Noh Chulsung Bae 《Journal of polymer science. Part A, Polymer chemistry》2010,48(19):4335-4343
Postfunctionalization of high‐molecular‐weight syndiotactic polystyrene (sPS) was achieved via combination of electrophilic bromination at the para‐position of the polymer aromatic ring and subsequent Suzuki–Miyaura cross‐coupling reactions with functionalized phenylboronic acids. The concentration of brominated styrene repeating unit in sPS was conveniently controlled by changing the ratio of added bromine relative to the polymer repeating unit. Brominated sPS (8.5 mol %) was converted quantitatively to other polar functional groups via Suzuki–Miyaura cross‐coupling reactions with various functional group‐substituted phenylboronic acids. The surface properties of functionalized sPS were studied by measuring water contact angles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4335–4343, 2010 相似文献