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11.
Some surface aspects of the thermal and X-ray induced degradation of a cellulose nitrate have been studied by FAB/SIMS.The pristine material gives peaks at 30 and 46 amu, indicative of NO+ and NO2+ originating from the nitrate ester groups. The thermally degraded material indicates these peaks at slightly lower intensities, whereas the X-ray degraded material shows little evidence for their appearance. These data complement recent ESCA data on the same systems.1The conclusion is that electromagnetic degradation is predominantly a surface effect, whereas thermal degradation is a bulk oriented phenomenon. 13C nmr has been used to add further evidence for this last point. 相似文献
12.
Neil Burford Jack Passmore Xiaoping Sun 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):487-488
13.
Patricio V Poblete J.Ian Munro 《Journal of Algorithms in Cognition, Informatics and Logic》1985,6(3):336-350
A detailed analysis is presented for the behaviour of binary search trees built by using a heuristic that performs only local reorganizations at the bottom of the tree. 相似文献
14.
The carbon-13 NMR spectra have been recorded for representatives of three previously unexamined classes of pentacyclic triterpenes—lupanes, fernanes and arboranes. In addition to the spectra of lupeol methyl ether, cylindrin and arundoin, the spectra of a number of other triterpene methyl ethers are also recorded. The effect of methyl ether formation on the shilding values for carbons in the 3β-hydroxy-4,4-dimethyl- ring A system is defined. 相似文献
15.
Total luminescence yield of toluene and mesitylene, isolated in rare-gas matrices, has been measured as a function of excitation energy in the energy range covering the absorption region of both host and guest. Energy transfer from the host to the dopant is apparent. An increase in the luminescence yield is observed at the host exciton state. Luminescence excitation spectrum of pure mesitylene is presented. 相似文献
16.
An oxidoditerpene, isolated from the heartwood of Dacrydium colensoi, has been shown to be 18-hydroxy-2-ketomanoyl oxide (V). 相似文献
17.
Photoemission yield spectra of solid argon using synchrotron radiation for excitation in the photon energy range 11.7–16 eV show peaks closely following the known excitonic transitions, further peaks at 11.96 and 13.1 eV and also give an indication for band-gap photoconductivity. 相似文献
18.
Dewald EL Suter LJ Landen OL Holder JP Schein J Lee FD Campbell KM Weber FA Pellinen DG Schneider MB Celeste JR McDonald JW Foster JM Niemann C Mackinnon AJ Glenzer SH Young BK Haynam CA Shaw MJ Turner RE Froula D Kauffman RL Thomas BR Atherton LJ Bonanno RE Dixit SN Eder DC Holtmeier G Kalantar DH Koniges AE Macgowan BJ Manes KR Munro DH Murray JR Parham TG Piston K Van Wonterghem BM Wallace RJ Wegner PJ Whitman PK Hammel BA Moses EI 《Physical review letters》2005,95(21):215004
The first hohlraum experiments on the National Ignition Facility (NIF) using the initial four laser beams tested radiation temperature limits imposed by plasma filling. For a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with an analytical model that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits with full NIF (1.8 MJ), greater, and of longer duration than required for ignition hohlraums. 相似文献
19.
Grant DM Elson DS Schimpf D Dunsby C Requejo-Isidro J Auksorius E Munro I Neil MA French PM Nye E Stamp G Courtney P 《Optics letters》2005,30(24):3353-3355
We demonstrate an optically sectioned fluorescence lifetime imaging microscope with a wide-field detector, using a convenient, continuously tunable (435-1150 nm) ultrafast source for fluorescence imaging applications that is derived from a visible supercontinuum generated in a microstructured fiber. 相似文献
20.
Requejo-Isidro J McGinty J Munro I Elson DS Galletly NP Lever MJ Neil MA Stamp GW French PM Kellett PA Hares JD Dymoke-Bradshaw AK 《Optics letters》2004,29(19):2249-2251
We report the development of a high-speed wide-field fluorescence-lifetime imaging (FLIM) system that provides fluorescence-lifetime images at rates of as many as 29 frames/s. A FLIM multiwell plate reader and a potentially portable FLIM endoscopic system operating at 355-nm excitation have been demonstrated. 相似文献