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991.
State-of-the-art compact recirculating electron accelerators operating at intermediate energies (tens of MeV) are reviewed. The acceleration schemes implemented in the rhodotron, ridgetron, fantron, and cylindertron machines are discussed. Major accelerator components such as the electron guns, accelerating cavities, and bending magnets are described. The parameters of currently operating recirculating accelerators are tabulated, and applications of these accelerators in different processes of irradiation are exemplified. 相似文献
992.
The present study used differential scanning calorimetry, thermogravimetric analysis, and UV spectrometry to examine: i) the encapsulation of an organic UV filter 1-(4-methoxyphenyl)-3-(4- tert-butylphenyl)propane-1,3-dione (avobenzone) within modified dextrin and ii) the characteristics of these inclusion complexes (MDA). The properties of avobenzone emulsions with and without encapsulation in modified dextrin, the in vitro UV protection factor, dissolution and release, and the skin penetrability of avobenzone were also examined. The presence of inclusion complexes significantly decreased the tendency of the UV filter to penetrate the skin. In addition, such inclusion complexes should effectively prevent skin damage from radiation extending from the UVA to the UVC. 相似文献
993.
994.
Ching-Yang Cheng 《Transport in Porous Media》2012,91(3):877-888
This work studies the Soret and Dufour effects on the double-diffusive free convection over a downward-pointing vertical truncated
cone with variable wall heat and mass fluxes in fluid-saturated porous media. A coordinate transformation is used to derive
the nondimensional boundary-layer governing equations, and the obtained nonsimilar equations are then solved by the cubic
spline collocation method. Results for local surface temperature and the local surface concentration are presented as functions
of Soret parameters, Dufour parameters, power-law exponents, buoyancy ratios, and Lewis numbers. Results show that increasing
the Dufour parameter tends to increase the local surface temperature, while it tends to decrease the local surface concentration.
An increase in the Soret number leads to a decrease in the local surface temperature for buoyancy assisting flows, while it
leads to an increase in the local surface temperature for buoyancy opposing flows. Increasing the Soret number tends to increase
the local surface concentration. Moreover, the local surface temperature and the local surface concentration of the truncated
cones with higher power-law exponents are lower than those with lower exponents. 相似文献
995.
The paper presents a short review on the synthesis, characterisation and selected medical applications of poly(styrene/α-tert-butoxy-ω-vinylbenzyl-polyglycidol) (P(S/PGL)) microspheres. The soap-free emulsion-polymerisation of styrene and α-tert-butoxy-ω-vinylbenzyl-polyglycidol macromonomer (PGL) in water yielded core-shell microspheres with a low particle-diameter dispersity
(ratio of the weight average particle diameter and the number average particle diameter). The interfacial fraction of PGL
units, estimated by XPS, was in the range of 0–42 mole % depending on the concentration of the macromonomer in the polymerisation
feed. The studies of adsorption of model proteins showed that the surface fraction of adsorbed protein was significantly reduced
when the PGL interfacial fraction was higher than 40 mole %. The P(S/PGL) particles with covalently immobilised proteins were
used for the preparation of photonic crystal assemblies suitable for applications in optical biosensors and the medical diagnostic
test for the detection of Helicobacter pylori antibodies in the blood serum. 相似文献
996.
This paper reports the fabrication and nanofiltration properties of a sol–gel derived microporous zirconia membrane. Effects
of synthesis parameters, including hydrolysis time, hydrolysis temperature, hydrolysis ratio and chelating agent dopant, on
the state and size of polymeric zirconia sol, were investigated. Highly reproducible and stable zirconia sol after refluxing
at 40 °C for 180 min, with an average particle size of approximately 8.6 nm, was synthesized with a recipe of [Zirconium n-propoxide]:
[Diethanolamine]: [1-propanol]: [H2O] being 1: 2.2: 28.7: 9.4 (in molar ratio). The sol was subsequently used for the fabrication of microporous ZrO2 membranes onto alumina supported mesoporous γ-Al2O3 layers. ZrO2 membranes with molecular weight cut-off (MWCO) of 354, 1,195, corresponding to the pore size of 0.94 and 1.75 nm, were successfully
fabricated. Ionic retention properties of such ZrO2 membranes with respect to electrolyte solutions, like MgCl2, CaCl2, NaCl and Na2SO4, were also determined. Effects of parameters such as concentration of salt solutions and trans-membrane pressure on retention
rates of microporous ZrO2 membranes were studied in detail. Results showed that zirconium n-propoxide derived microporous ZrO2 membranes exhibited comparatively high retention rates towards divalent ions like Mg2+ and Ca2+, while much lower retention rates were observed for mono-valent ion (Na+) in the present study, which are the characteristics of nanofiltration membranes. 相似文献
997.
998.
Monte Carlo study of impact ionization in n-type InAs induced by intense ultrashort terahertz pulses
Electron impact ionization induced in n-type InAs by single-cycle pulses of picosecond and subpicosecond duration has been investigated by Monte Carlo method. It is established that the rate of generation of electron–hole pairs decreases with the decrease of the pulse duration. The impact ionization threshold field is found to depend linearly on frequency for the fields oscillating at frequencies much higher than reciprocal momentum relaxation time. Good agreement between calculations and available experimental data has been obtained. 相似文献
999.
1000.