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101.
A simple expression of the α-nucleus optical potential has been derived from the Feshbach formula by using a closure approximation for summing over the excited states of the target nucleus. It has been shown that the correction to the real folding model potential is small. The imaginary local potential equivalent to the non-local Feshbach potential has been studied in detail for Ca nuclei and shown to reproduce quite well the gross properties of empirical potentials above 100 MeV with, however, a lack of absorption in the surface region. The A-dependence of the imaginary potential volume integral has also been investigated. 相似文献
102.
The perfluorinated polymer Nafion and porous PTFE/Nafion composite membranes have been employed as supports for nickel complexes or for platinum and palladium metal particles. The resultant materials have been employed as catalysts in various olefin conversion processes. Supported platinum and palladium metal systems were evaluated as catalysts for the hydrogenation of cyclohexene. Rates of reaction are better than those of commercially available catalysts; turnover numbers in excess of 6000 have been obtained with no poisoning apparent. Catalysts may be regenerated many times. The reduction rate approaches a limit at high pressures of hydrogen and has an activation energy of 13 kJ mol?1 in neat cyclohexene. Nafion was employed as a strong acid cocatalyst to activate and then support a nickel complex catalyst. The resultant catalyst was active for double-bond-shift isomerization. 相似文献
103.
104.
An antisymmetrized microscopic calculation of the optical potential for nucleon-40Ca elastic scattering is derived. RPA correlations taken into account in the one-particle mass operator are shown to bring a correction to the first-order real potential at low energies and to lead to an imaginary potential. Both are calculated for incident nucleon energies between 10 and 50 MeV. Their general properties are studied in great detail and, after comparison with empirical imaginary potentials, the reliability of such an approach is discussed according to the value of the incident energy. 相似文献
105.
106.
The aim of this Note is to give a sufficient condition in order for a function in the global domain of definition of the Monge–Ampère operator not to belong to the local domain of the former in the sense of Cegrell, when one looks at the n-dimensional complex projective space. Using this result, we show that the subsolution theorem is false for functions in the local domain of definition of the Monge–Ampère operator on such a projective space. 相似文献
107.
108.
Shien-Kuei Liaw Cheng-Kai Huang Yuan–Lung Hsiao Li-Chuan Mau Hong-Xi Cao Ji-Bin Horng Keang-Po Ho 《Optical and Quantum Electronics》2006,38(7):625-631
A miniature-size erbium doped fibre amplifier (MS-EDFA) is constructed with a saturation power of 17.0 dBm and low noise figure
of 5.2 dB using an uncooled pump laser. The MS-EDFA has achieved low polarization dependent gain, large signal gain and small
signal gain of 0.05 dB, 15 dB (at Pin = +2 dBm) and 42 dB (at Pin = −30 dBm), respectively, with negligible temperature dependent
gain. The dimension of MS-EDFA is only twice than a typical credit card. 相似文献
109.
Spatial periodic forcing of pattern-forming systems is an important, but lightly studied, method of controlling patterns. It can be used to control the amplitude and wave number of one-dimensional periodic patterns, to stabilize unstable patterns, and to induce them below instability onset. We show that, although in one spatial dimension the forcing acts to reinforce the patterns, in two dimensions it acts to destabilize or displace them by inducing two-dimensional rectangular and oblique patterns. 相似文献
110.