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Electron spin resonance spectroscopy has been used to investigate radiation damage in an irradiated single crystal of maleic acid. At least two stable radicals are produced by the radiation. One of these radicals is probably HOOC-H2C-CH-COOH. Another species, possibly of the form HOOC-RCH-CH-COOH, has also been observed. Radical yields have been measured for the isomeric maleic and fumaric acids. The G-values are 0.1 for maleic acid and 0.06 for fumaric acid. 相似文献
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A. Shumelyuk A. Volkov S. Odoulov G. Cook D. R. Evans 《Applied physics. B, Lasers and optics》2010,100(1):101-108
Coupling of two counterpropagating coherent light waves in tin hypothiodiphosphate (Sn2P2S6, SPS) is usually strongly inhibited because of severe space charge limitations. Analysis of two-beam coupling gain is performed
for different orientations of the grating vector in this monoclinic crystal that takes into account the anisotropy of dielectric
permittivity. Gain enhancements are predicted and demonstrated experimentally for several nontraditional orientations of counterpropagating
waves. 相似文献
47.
The liquid crystalline behaviour of methyl-6-O-(n-dodecanoyl)-α-D-glucopyranoside, 1, has been characterised using X-ray diffraction and variable temperature Fourier transform infrared (FTIR spectroscopy). 1 exhibits a monotropic interdigitated smectic A phase consisting of bilayers in which the alkyl chains are overlapped. The crystal–isotropic transition is accompanied by a pronounced decrease in the strength of the hydrogen bonding network involving the sugar groups resulting in a marked change in the environment of the alkyl chains. The isotropic phase consists of disordered smectic-like domains stabilised via hydrogen bonding between the sugar groups. At the transition to the smectic A phase, a subtle change in hydrogen bonding is observed which is manifested by a change in the temperature dependence of the OH stretching peak position in the FTIR spectrum. On crystallisation, the strong hydrogen bonding network is re-established accompanied by a change in the conformational distribution of the alkyl chains. A model is proposed in which a combination of hydrogen bonding (enthalpic effects) and conformational arrangements (entropic effects) promotes initially the formation of smectic-like domains in the isotropic phase and subsequently stabilises the smectic A phase by inhibiting the microphase separation leading to the crystal phase. 相似文献
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Vaman C Andreoiu C Bazin D Becerril A Brown BA Campbell CM Chester A Cook JM Dinca DC Gade A Galaviz D Glasmacher T Hjorth-Jensen M Horoi M Miller D Moeller V Mueller WF Schiller A Starosta K Stolz A Terry JR Volya A Zelevinsky V Zwahlen H 《Physical review letters》2007,99(16):162501
Rare isotope beams of neutron-deficient 106,108,110Sn from the fragmentation of 124Xe were employed in an intermediate-energy Coulomb excitation experiment. The measured B(E2,0(1)(+)-->2(1)(+)) values for 108Sn and 110Sn and the results obtained for the 106Sn show that the transition strengths for these nuclei are larger than predicted by current state-of-the-art shell-model calculations. This discrepancy might be explained by contributions of the protons from within the Z = 50 shell to the structure of low-energy excited states in this region. 相似文献
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Reallocation of input resources (RIR) is a process by which certain decision making units (DMUs) reallocate resources among themselves; a process that occurs frequently in many enterprises. In this paper, a new data envelopment analysis (DEA) approach is developed to select the best cooperative partner DMU. Context-dependent DEA is used to identify the different levels of best-practice frontiers. Two DEA-based models are established for two cooperative scenarios, namely, resources pooling only and best-practice sharing. A cooperative method is applied to determine how to reallocate the input resources, and Shapley value is used to estimate the revenue changes that the various DMUs should expect after RIR. Two different situations with different objectives are considered. One objective is to maximize total revenue for the partnership, while the other is to maximize the Shapley value. The proposed approaches are illustrated with two examples. 相似文献