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991.
It is possible to overcome the Abbe limit of resolution by a factor two. For this one needs the A PRIORI knowledge, that the object is not birefringent or dichroic. That is to say, the object acts identically on both of the independant polarization components of the incident light. Then already one polarization component would be enough to form an image as complete as it is permitted by the lens system and by the aperture. The other polarization component would produce an identical image. Hence the capacity of the other polarization component to carry information from the object plane to the image plane is vasted. This vaste can be avoided by means of a special set up, containing e.g. twoWollaston prism. The result is the doubling in resolution without any increase of the aperture. This has been confirmed experimentally both for coherent and incoherent illumination. 相似文献
992.
A. Bäcklin N.G. Jonsson R. Julin J. Kantele M. Luontama A. Passoja T. Poikolainen 《Nuclear Physics A》1981,351(3):490-508
0+ states and their depopulating E0 and E2 transitions have been studied in 112–124Sn. Several methods of γ-ray and electron spectrometry have been employed, including special coincidence techniques for lifetime, conversion electron and double Coulomb excitation measurements. For 114–118Sn the E2 transition probabilities from the first excited 0+states (02+) are about 20 W.u., which is compatible with a vibrational two-phonon character. Also the E0 transition probabilities from these states are within a factor of two from the vibrational values. For the second excited 0+ states (03+) the corresponding E2 and E0 transition probabilities are considerably smaller. A total of 12 E0 transitions have been observed. The 03+ → 02+ transition is observed in 114–120Sn and has in 116Sn a reduced transition probability 1–2 orders of magnitude larger than those of the groundstate E0 transitions, which indicates that the 03+ and 02+ states are strong mixtures of components with different 〈r2〉. The 0+ states in 116Sn are discussed as possible rotational band heads associated with a deformation β2 ≈ 0.2. The Coulomb excitation cross section of the 02+ state is found to be sensitive to an interference term including matrix elements with the 22+ state. The relative sign of this term has been determined. 相似文献
993.
Kinetic energy spectra, charge and angular distributions have been measured with ΔE-E telescopes for over twenty-five identified elements from the reaction . At all angles and for all observed atomic numbers, the energy spectra indicate the presence of energetically relaxed products in the vicinity of the Coulomb barrier. Elements near the projectile also show a sizable contribution from incompletely damped events at angles close to the grazing angle. The charge distributions are peaked near the projectile Z and demonstrate a strong shape dependence on the angle of observation. The angular distributions show a weakening of the side peaking with increasing proton transfer to or from the projectile. Angular distributions and angle-integrated charge distributions have been calculated with a diffusion model which assumes the formation of a rotating intermediate complex with an l-dependent lifetime. The mass exchange between the two segments of the intermediate complex is treated as a diffusive process which is described by the master equation. Values for the diffusion constant, the overlap of the two density distributions, the mean lifetime of the intermediate complex and the spread in the average lifetime were used which semiquantitatively reproduced data from the 620 MeV 86Kr reaction on 181Ta and 197Au targets. Satisfactory agreement was obtained between these calculations and the data from the 159Tb target. In addition, by increasing the lifetime of the complex by 30 %, the previously measured data for the 107, 109Ag + 620 MeV 86Kr reaction was semiquantitatively reproduced. 相似文献
994.
H. -G. Clerc W. Lang H. Wohlfarth K. -H. Schmidt H. Schrader K. E. Pferdekämper R. Jungmann 《Zeitschrift für Physik A Hadrons and Nuclei》1975,274(3):203-213
The mass separated fission product beam provided by the mass separator “Lohengrin” has been used to determine the nuclear charge distribution for the thermal-neutron-induced fission of235U for all light fission products in the region 80≦A≦107. The measurements were performed at the most probable kinetic energy of the fission products. By using the known fission product mass yields, the independent yields for a total number of 100 nuclides were obtained under the condition of the most probable kinetic energy. The proton pairing effect modulates the average nuclear charge of the fission fragments and the isobaric charge distribution widths in a regular fashion. The probabilities of breaking a pair and of forming fragments with an energetically unfavourable neutron-to-proton ratio are found to compete with each other. Both probabilities depend on the mass split and reach their maximum values in the region of the most probable masses. The odd-even-proton effect is found to vary smoothly between 16% for the most abundant mass splits and 40% for the rare mass splits. The odd-even-neutron effect exhibits maxima nearN=50 andN=60, where it reaches 16%. These maxima and the extremely low Tcyield (0.13±0.05%) are discussed with regard to fragment shell effects. 相似文献
995.
996.
Göran Fäldt 《Annals of Physics》1983,148(2):327-345
Various symmetries of inelastic proton-nucleus scattering within the Glauber model are discussed. They are obtained from symmetries of the corresponding proton-nucleon amplitude. In particular, it is shown that the polarization and analyzing power are in general not equal. 相似文献
997.
We report on the observation of Kαα X-rays of Si, produced in collisions of 15–28 MeV Si projectiles with various target atoms in the range Z = 6 to 29. Energy shifts of X-rays were measured and are compared with theoretical predictions. Cross section ratios for emission of Kαα and Kα radiation are given. 相似文献
998.
999.
Z- as well as E-isomers of 1,2-diarylbutadienes undergo Diels-Alder reactions with nitrosobenzenes regiospecifically, but the adducts have different structures (3 or 4, respectively) in both cases. From kinetic results it is concluded that the somewhat anomalous cycloaddition of the E-isomers is facilitated and directed by the intermediate formation of a CT-complex. 相似文献
1000.
The angular resolved energy distribution of true secondary electrons emitted normal to a clean W(100) surface has been measured with a 180° Spherical Deflector Analyzer. While significant discrepancies are found with earlier secondary emission data, good agreement exists with angular resolved photoemission spectra. Comparison to recent band structure calculations (density of states effects) is made. The fine structure of the secondary emission spectrum is fully explained by numerical results obtained by means of a quantitative theory of angular resolved secondary emission. Further, the fine structure corresponds closely to reflection coefficient data. 相似文献