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161.
Experimental measurements of the electric form factor of the neutron indicate a spatially inhomogeneous distribution of charge. The quark model, with a spatially dependent spin-spin interaction, can accurately describe this inhomogeneity. We relate the neutron's charge radius to the nucleon-delta mass difference and discuss other experimental consequences of the inhomogeneity. 相似文献
162.
The influence of crystallinity and crosslinking on the depression of the glass transition temperature in nylon 6 by water has been investigated by dynamic mechanical methods. Radiation crosslinking by high-energy electrons was effective in preventing morphological changes during the measurement of the incremental change in heat capacity (ΔCp) at Tg, which was performed by differential scanning calorimetry. The experimentally determined value of ΔCp, when normalized to account for the crystalline phase, was found to deviate from a linear two-phase relation and was reduced further than would be expected based on this model. It is proposed that nylon 6 is best described by a three-phase model which consists of a crystalline domain, a wholly amorphous domain, and an “intercrystalline” region. The importance of this in explaining the relatively large depression of Tg by small quantities of water is illustrated by applying equations derived to account for the compositional dependence of Tg in polymerdiluent mixtures, based on a classical thermodynamic interpretation of the glass transition phenomenon. 相似文献
163.
M.A. Firestone J. Jänecke A. Dudek-Ellis P.J. Ellis T. Engeland 《Nuclear Physics A》1976,258(2):317-340
The reaction 16O(d, 3He)15N has been investigated using 29 MeV deuterons, and angular distributions were obtained for levels in 15N up to 10 MeV excitation energy. The measured distributions were subjected to distorted-wave (DWBA), compound nucleus (Hauser-Feshbach) and coupled-channel (CCBA) analyses. Only the strong transitions to the ? ground state and the ? state at 6324 keV exhibit distributions which are well described by DWBA. The spectroscopic factors are in agreement with shell-model estimates. The weak transitions generally show little structure and the spectroscopic factors extracted for these transitions tend to be unreasonably large. Contributions from compound nucleus formation were estimated and found to vary between about 10 % and 100 % of the observed cross sections with an average of the order of 30 %. The CCBA analysis for the transitions to the , + and + states at 5271, 7155 and 7566 keV, respectively, was performed using the spectroscopic amplitudes from weak coupling shell-model wave functions. Inelastic excitations to one-phonon states in the target and residual nuclei were included. The agreement between calculated and experimental distributions is good for both shape and magnitude, a conclusion which is not disturbed by the addition of small compound nucleus contributions. It is evident that spectroscopic factors extracted for the weak transitions on the basis of a direct one-step reaction mechanism alone are unreliable. 相似文献
164.
Graham Ellis 《Archiv der Mathematik》1996,66(6):467-469
165.
The generalized Curie-Weiss model is an extension of the classical Curie-Weiss model in which the quadratic interaction function of the mean spin value is replaced by a more general interaction function. It is shown that the generalized Curie-Weiss model can have a sequence of phase transitions at different critical temperatures. Both first-order and second-order phase transitions can occur, and explicit criteria for the two types are given. Three examples of generalized Curie-Weiss models are worked out in detail, including one example with infinitely many phase transitions. A number of results are derived using large-deviation techniques. 相似文献
166.
Results obtained from the photolysis of ketene with acetylene strongly support the formation of C3H3 radicals in the title reaction. Stationary state studies are interpreted in terms of the reaction with a rate constant (109.8 s?1) which is compared to RRKM predictions. In pulsed laser induced decomposition experiments, recombination products involving C3H3 have been detected (some for the first time) and their formation modeled using step (3) with the same rate constant. 相似文献
167.
Titanium Auger electron spectra undergo radical changes similar to oxidation in forming the U2Ti intermetallic compound, whereas uranium spectra are relatively unmodified. These results indicate that Ti is an electron donor species in U2Ti compound formation. 相似文献
168.
The application of Hadamard transform spectroscopy (HTS) to analytical atomic spectroscopy has been investigated. A theoretical examination of the signal to noise ratio indicates that HTS offers a slight multiplex advantage over single slit scanning of the spectrum for the measurement of intense lines, as in atomic absorption, but is disadvantageous for measuring small signals in atomic emission and fluorescence. Using a simple HT spectrometer Mg and Pb were determined simultaneously by flame atomic absorption spectrometry. Sensitivities similar to those of conventional systems were obtained but, owing to instrumental imperfections and a short data collection time, detection limits were worse. Optimum system performance was obtained when the mask interval width was equal to the width of the image of the spectrometer entrance slit. Greater spectral detail was revealed by superposition of a set of computed spectra in which the starting point of each spectrum was displaced from the others by a distance less than the interval width of the Hadamard mask. This approach gave improved spectra without increased instrumental complexity. 相似文献
169.
R. Webb G. Trilling V. Telegdi P. Strolin A. Staude B. Shen P. Schlein J. Rander B. Naroska F. Muller T. Meyer W. Marsh W. Lockman J. Layter A. Kernan H. Foeth R. Ellis A. Böhm L. Baksay 《Physics letters. [Part B]》1975,55(3):336-340
We report the observation of double diffraction dissociation in the process p + p → (pπ+π?) + X at √s of 45 GeV and momentum transfer in the ?t range 0.15?0.53 GeV2 at the CERN ISR. The relative rates for elastic, single and double dissociation reactions measured here are found to agree with the prediction of Pomeron factorization. 相似文献
170.
We have employed a fast field reversal technique to demonstrate the existence of inertial effects in the motion of negative ions through isotopically pure He II at 70 mK. 相似文献