The lifetime and magnetic moment of43Ti (Iπ-7/2−, T1/2=0.50 sec), one of the mirror beta-radioactive nuclei in the f7/2-shell, have been measured with a fragment separator built at the Bevalac of the LBL. By means of the beta-NMR method on43Ti, a preliminary value of the magnetic moment of43Ti was determined to be μ=(0.70±0.07) μπ. 相似文献
Deeply bound hole states in the odd tin isotopes 115, 117, 119, 123Sn were investigated by using 81 MeV (3He, α) and 52 MeV (p, d) reactions. Excitation of low-spin states was largely suppressed in (3He, α) reactions due to the angular-momentum mismatch so that the excitation energies and widths of the states have been clearly determined. DWBA analyses showed that the deeply bound hole states have spectroscopic factors less than 20% of the sum-rule limit. Isobaric analog states corresponding to the ground and two lowest excited states of In isotopes were investigated in 115, 117, 119, 121, 123Sn isotopes. Coulomb displacement energies were deduced. DWBA analyses of these states were used to check the calculations for the deeply bound states. The spectroscopic factors of the analog states are in good agreement with the sum-rule prediction. 相似文献
Low-lying excited states of 124,126Xe and 132Ba have been studied by means of in-beam γ-ray spectroscopy in (p, xny) reactions. Excitation functions, angular distributions and γ-γ coincidence spectra were obtained. The 22+ , 3+, 42+ and 5+ levels were observed at the following excitation energies in keV: 846.4(22+), 1247.5(3+), 1437.3 (42+), 1836.6(5+) in 124Xe, 879.7(22+), 1317.3(3 +), 1488.2(42+), 1903.1(5 +) in 126Xe and 1032.1(22+), 1511.3(3+), 1729.9(42+) in 132Ba. The 2214.3 and 2561.7 keV levels in 126Xe were tentatively assigned as the 62+ and 7+ levels, respectively. These 22+, 3 +, 42+, 5+, 62+and 7+ levels are interpreted as members of a quasi-γ band. The E2/M1 mixing ratios of the 22+ → 21+ transitions in 124,126Xe and 132Ba were obtained as + 6.3+5.3?2.0 + 10.87.8?3.2 and + 8.3+4.9?2.2, respectively. 相似文献
The steady-state viscosity η, the dynamic viscosity η′, and the storage modulus G′ of several high-density and low-density polyethylene melts were investigated by using the Instron rheometer and the Weissenberg rheogoniometer. The theoretical relation between the two viscosities as proposed earlier is:\documentclass{article}\pagestyle{empty}\begin{document}$ \eta \left( {\dot \gamma } \right){\rm } = {\rm }\int {H\left( {\ln {\rm }\tau } \right)} {\rm }h\left( \theta \right)g\left( \theta \right)^{{\raise0.7ex\hbox{$3$} \!\mathord{\left/ {\vphantom {3 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}} \tau {\rm }d{\rm }\ln {\rm }\tau $\end{document}, where \documentclass{article}\pagestyle{empty}\begin{document}$ \theta {\rm } = {\rm }{{\dot \gamma \tau } \mathord{\left/ {\vphantom {{\dot \gamma \tau } 2}} \right. \kern-\nulldelimiterspace} 2} $\end{document}; \documentclass{article}\pagestyle{empty}\begin{document}$ {\dot \gamma } $\end{document} is the shear rate, H is the relaxation spectrum, τ is the relaxation time, \documentclass{article}\pagestyle{empty}\begin{document}$ g\left( \theta \right){\rm } = {\rm }\left( {{2 \mathord{\left/ {\vphantom {2 \pi }} \right. \kern-\nulldelimiterspace} \pi }} \right)\left[ {\cot ^{ - 1} \theta {\rm } + {\rm }{\theta \mathord{\left/ {\vphantom {\theta {\left( {1 + \theta ^2 } \right)}}} \right. \kern-\nulldelimiterspace} {\left( {1 + \theta ^2 } \right)}}} \right] $\end{document}, and \documentclass{article}\pagestyle{empty}\begin{document}$ h\left( \theta \right){\rm } = {\rm }\left( {{2 \mathord{\left/ {\vphantom {2 \pi }} \right. \kern-\nulldelimiterspace} \pi }} \right)\left[ {\cot ^{ - 1} \theta {\rm } + {\rm }{{\theta \left( {1{\rm } - {\rm }\theta ^2 } \right)} \mathord{\left/ {\vphantom {{\theta \left( {1{\rm } - {\rm }\theta ^2 } \right)} {\left( {1{\rm } + {\rm }\theta ^2 } \right)^2 }}} \right. \kern-\nulldelimiterspace} {\left( {1{\rm } + {\rm }\theta ^2 } \right)^2 }}} \right] $\end{document}. Good agreement between the experimental and calculated values was obtained, without any coordinate shift, for high-density polyethylenes as well as for a low density sample with low nw, the weight-average number of branch points per molecule. The correlation, however, was poor with low-density samples with large values of the long-chain branching index nw. This lack of coordination can be related to nw. The empirical relation of Cox and Merz failed in a similar way. 相似文献
A shock wave focusing initiation engine was assembled and tested in an experimental program. The effective pyrolysis rate of the pre-combustor was evaluated over a range of supplementary fuel ratio in this paper. Results highlight two operational modes of the resonant cavity: (1) pulsating combustion mode, (2) stable combustion mode. The appearance of the two combustion modes is jointly affected by the flow and the structural characteristic value of the combustion chamber. This paper uses images, time-frequency analysis, and nonlinear time series analysis methods to identify and distinguish these two combustion modes. It is believed that the interaction between the combustion chamber and the supply plenum is the probable reason for different combustion modes. The experiment has found that structural parameters and import flow parameters have an impact on the initiation of the combustion chamber. Increasing the injection pressure can appropriately broaden the fuel-rich boundary of initiation. Low equivalence ratio and high injection pressure can also appropriately increase the combustion working frequency in a small range. From the perspective of pressure utilization, under the premise of ensuring successful initiation, injection pressure should not be too high. 相似文献
Plasma cracking of n-decane is carried out in a new type of gliding arc flow reactor in the atmosphere of nitrogen and air, at a flow range of 25–45 L/min with an interval of 5 L/min. The relationship between arc evolution and discharge voltage and current signals is established by synchronous recording with high-speed camera and oscilloscope. It is recorded that the rotating frequency of the gliding arc is in the range of 81–176 Hz, which increases with the rise of the flow rate and has no direct relationship with the type of gas. When air is used as the discharge medium, although the luminous intensity of the arc is weak, arc rotation is relatively stable, and the specific input energy is higher, which is 58% higher than that of nitrogen. In addition, the partial oxidation of n-decane provides extra heat for cracking, which is helpful to improve the efficiency of plasma cracking. The cracking products mainly include hydrogen, ethylene, acetylene, methane, propylene and ethane. The concentration of each component is higher, reaching the maximum value at the flow rate of 40 L/min, with the hydrogen selectivity of 23.1%. However, when nitrogen plasma is selected, the kinds of products are reduced, containing only hydrogen, ethylene and acetylene, and the concentrations are lower than 0.5%. Two parameters, energy conversion efficiency and carbon based characterization effective cracking rate, were proposed to evaluate the cracking effect of flow reactor.
Electronic ground and excited states of anion radicals of cyanobenzene derivatives: 1,3,5-tricyanobenzene, 1,2,4,5-tetracyanobenzene, and tetracyanoquinodimethane (TCNQ) and nitrobenzene derivatives: nitrobenzene, p-nitroaniline, m-nitroaniline, and o-nitroaniline were theoretically investigated by the symmetry adapted cluster-configuration interaction (SAC-CI) method, which is able to produce accurate theoretical electronic excitation spectra even for radical doublet states. For all the target molecules, the present calculations reproduced the positive electron affinities, which were mostly in good agreement with the experimental values, and their features, especially for TCNQ, were characterised by singly occupied molecular orbitals as well as the number of the electron-withdrawing terminal groups. The excitation energies and their oscillator strengths by the SAC-CI method were also in good agreement with the corresponding experimental UV/VIS/NIR spectra observed by one of the authors and other experimental evidences. Except for TCNQ, the present theoretical calculations were successful to first predict the existences of the forbidden (or very low intense) pure valence excited states in near-infrared region. The physical natures of the observed intense spectral bands were clarified and some new assignments to their electronic states were provided. By extending the present work, photo-related molecular designs of new functional electron acceptors may be challenged. 相似文献