摘要:

AbstractThe Einstein approximation on which the averaging procedure in the recent dualistic approach is based is further elaborated and used to derive important results. This lends further credibility to the consistency of the procedure.

ISSN:0003-3804    

DOI:10.1002/andp.19885000602

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractAn idea to design a new converging collimator for cold neutron time‐of‐flight measurements is presented. Using this new facility in combination with a neutron time‐of‐flight spectrometer, we may have neutron intensity gain factors about three times that obtained using the conventional straight slit collimators. Expressions for calculating the collimators dimensions as well as the intensity gain and the time resolution broading were pr

ISSN:0003-3804    

DOI:10.1002/andp.19885000603

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractBy solving the system of equations for the doubletime Green functions, an expression for the energy spectrum of the spinsystem with the correction due to spin‐phonon interaction is derived. The utilized commutation relations for spin‐operators are more complicated than in the case of the spin‐wave approximation. In the lower temperature region, our expression becomes the one obtained by the spin‐wave approximation. The temperature dependence and the wave‐vector dependence of the broadening of the energy level are

ISSN:0003-3804    

DOI:10.1002/andp.19885000604

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractNuclear reactions between composite particles with rearrangement processes are considered. The cluster model is used in describing the structure of the nuclei. With this structure we have in the initial channel as well as in the final channel, four interacting particles. These reactions are studied as a four‐body problem. The scattering amplitudes are approximated by using a separable expansion for the separable potential model. The four‐body equations are reduced to integral equations in the form of exact effective two‐particle Lippmann‐Schwinger equations. These equations are solved by standard methods in a form suitable for numerical calculations. The present four‐body treatment is applied calculating the differential cross‐sections for different scattering and transfer nuclear reactions. Distorted wave Born approximation calculations are used in calculating the angular distributions. The present theoretical calculations are in good agreement with the experimental angular di

ISSN:0003-3804    

DOI:10.1002/andp.19885000605

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe nonperturbative vacuum structure of Quantum Chromodynamic is studied with the help of a generalization of the formalism of Green functions which corresponds to the method of Gorkov and Nambu in the theory of superconductivity. Taking into account the existence of gluon condensation the selfenergy of the gluon‐quasi‐particles is calculated with the help of modified rules for Feynman diagrams. The resulting integral equations for the effective field parameters contain particular solutions with an energy gap in the spectrum of the quasi‐particles and a phase transition at a critical mom

ISSN:0003-3804    

DOI:10.1002/andp.19885000606

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractMacroscopic matter is considered as a quantum statistical system of electrons and nuclei. After the discussion of several exact bounds and stability theorems, the low and high density structures of the thermodynamic functions (corresponding to ideal gases) are given. The intermediate regions in the density temperature plane are treated by means of thermodynamic Green functions. This requires partial summations corresponding to the effects of screening (chains), bound states (ladders), and chemical equilibria (quasi particle summations). The thermodynamic instabilities corresponding to the first order plasma phase transitions are studied for several examples.

ISSN:0003-3804    

DOI:10.1002/andp.19885000607

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractIn the present work the radial distribution of total gamma doses arising from the interaction of reactor neutrons and gamma radiations inside ilmenite heavy concrete shield are measured. The ilmenite concrete is pierced with neutral beam injector ducts having different diameters and lengths. The results obtained show a relative increase in radial gamma doses at a distance of 10 cm from the neutral beam end. An empirical formula was obtained, fitting the measured gamma doses at the peak position in good agreement within a factor of 1.27. Moreover the variation of the total gamma radiation was measured along straight filled ducted with different diameters and length. The experimental data obtained show a reasonable agreement with calculated ones. The scattered as well as unscattered components of the gamma radiation transmitted through a straight duct were investigated. An empirical formula describing this behaviour was obtained.

ISSN:0003-3804    

DOI:10.1002/andp.19885000608

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0003-3804    

DOI:10.1002/andp.19885000609

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0003-3804    

DOI:10.1002/andp.19885000610

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0003-3804    

DOI:10.1002/andp.19885000601

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY