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51.
Novel reductive chlorination of 3-aryl-2,1-benzisoxazoles with thionyl chloride is described. The chlorinated aminobenzophenones have been characterised.  相似文献   
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The scattering and absorption differential cross sections for nonlinear QED process such as double photon Compton scattering have been measured as a function of independent final photon energy. The incident gamma photons are of 0.662 MeV in energy as produced by an 8 Ci137Cs radioactive source and thin aluminum foils are used as scatterer. The two simultaneously emitted photons in this process are detected in coincidence using two Nal(T1) scintillation detectors and a slow-fast coincidence set-up of 30 nsec resolving time. The measured values of scattering and absorption differential cross sections agree with theory within experimental estimated error.  相似文献   
54.
We calculate the neutron-evaporation residue cross sections σ 3n , σ 4n , and σ 5n in the hot-fusion reactions 48Ca+242,244Pu →290,292114 ? over a wide range of compound-nucleus excitation energies ( $E_{\text{CN}}^{*}$ = 34–53 MeV). We work with the dynamical cluster-decay model (DCM), with a single parameter, the neck-length parameter ΔR. To calculate neutron-evaporation cross sections, we choose the superheavy proton magic Z = 126 and neutron magic N = 184. Among the 3n, 4n, and 5n production cross sections for 290, 292114?, only the 3n decay cross sections of 292114? correspond to spherical fragmentation. The 4n and 5n cross sections of 292114? and 3n, 4n, and 5n cross sections of 290114? could only be fitted after the inclusion of quadrupole deformations β 2i within the optimum orientation approach. Changes in the angular momentum and N/Z ratio do not significantly influence the fragmentation paths of 290, 292114? superheavy nuclei. Larger barrier modification is required for the lower angular momentum states and lighter neutron clusters. The contribution of the fusion–fission component is also computed for the compound nucleus 292114? in the energy range $E_{\text{CN}}^{*}$ = 27–47 MeV.  相似文献   
55.
The effective atomic numbers of composites and Rayleigh-to-Compton cross-section ratio of elements, in the range 6 ≤ Z ≤ 82 for 145 keV gamma photons, are determined experimentally. An HPGe (high purity germanium) semiconductor detector is placed, at scattering angle of 90°, to record the spectra originating from interactions of incident gamma photons with the target under investigations. The intensity ratio of Rayleigh-to-Compton scattered peaks, corrected for photo-peak efficiency of gamma detector and absorption of photons in the target and air column, is plotted as a function of atomic number and a best fit-curve is constituted. From this fit-curve, the respective effective atomic numbers of the scientific samples are determined. The measured values of cross-section ratio increases non-linearly with increase in atomic number and are found to agree with theoretical predictions based upon non-relativistic form factor, relativistic form factor, modified form factor and S-matrix theory.  相似文献   
56.
We measure the group delay in an on-chip photonic-crystal device with two resonators side coupled to a waveguide. We demonstrate that such a group delay can be controlled by tuning either the propagation phase of the waveguide or the frequency of the resonators.  相似文献   
57.
Benzofuroxan reacts with imines derived from crotonaldehyde and cinnamaldehyde, to form 2-imino-methylquinoxaline 1,4-dioxides.  相似文献   
58.
A series of 5-(2-nitro-l-phenyl)ethyluracils were obtained when β-nitrostyrenes were reacted with 1,3-di-methyl-6-substituted uracil derivatives, instead of cyclic compounds. The structures of the compounds 5, 6 , and 7 were proved by spectroscopic methods and their mass fragmentation patterns are discussed.  相似文献   
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