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1.
2.
T. Van Cauteren J. Ryckebusch B. Metsch H. -R. Petry 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):613-615
We present some of our results for the electromagnetic properties of excited Σ hyperons, computed within the framework of the Bonn constituent-quark model, which is based on the Bethe-Salpeter approach.
The seven parameters entering the model are fitted against the best-known baryon masses. Accordingly, the results for the
form factors and helicity amplitudes are genuine predictions. We compare with the scarce experimental data available and discuss
the processes in which Σ
*'s may play an important role. 相似文献
3.
The synthesis of 5,8-difluoronaphtho[2,3-c]thiophene-4,9-dione ( 2a ) has been accomplished. Treatment of 2a with 2,2-dimethylaminoethylamine leads to 2-[2-(dimethylamino)ethyl]-5-[2-(dimethylamino)ethylamino]-8-fluoronaphtho[2,3-c]pyrrole-4,9-dione ( 6 ). 相似文献
4.
V. V. Anisovich B. Ch. Metsch H. R. Petry A. V. Sarantsev 《Zeitschrift für Physik A Hadrons and Nuclei》1995,351(4):417-433
We investigate a special concept of quarkhadron duality in meson physics at low and intermediate energies. With a relativistic propagator for confined quarks, we calculated masses and widths of the mesons which areS- andP-wave states ofq¯q (J P=0?, 1?, 0+, 1+c, 2+) as well as meson-meson scattering amplitudes at energies up totrs ≤ 1.3 GeV by including light pseudoscalar and vector mesons into the interaction dynamics. Our investigation shows that the influence of the light meson dynamics resutls in:
- a contribution to the constituent quark mass of approximately 200 MeV.
- the appearance of a new soft confinement force barrier responsible for the formation of the highly excited meson states.
5.
J. Wuttke M. Kiebel E. Bartsch F. Fujara W. Petry H. Sillescu 《Zeitschrift für Physik B Condensed Matter》1993,91(3):357-365
We present an extended set of incoherent neutron scattering measurements on the van der Waals liquido-terphenyl, obtained by time-of-flight and backscattering spectroscopy. In the supercooled liquid regime, data from three instruments are combined and analysed in terms of the selfcorrelationS(Q, t). In the time range 1...100 ps, the crossover from -to -relaxation is well described by the masterfunction of mode coupling theory, and fitted parameters are consistent with the previously established critical temperatureT
c
[Z. Phys. B83, 175 (1991)]. In the glassy regime, vibrations are harmonic and can be described by a density of states. Deviations at lowQ are quantitatively explained by a multiple scattering simulation. Throughout the article, experimental difficulties are discussed in some detail. 相似文献
6.
7.
Franz Petry 《Microscopy and microanalysis》2004,10(5):586-601
Cryptosporidium parvum (Apicomplexa, formerly Sporozoa) is the causative agent of cryptosporidiosis, an enteric disease of substantial medical and veterinary importance. C. parvum shows a number of unique features that differ from the rest of the class of coccidea in which it is currently grouped taxonomically. Differences occur in the overall structure of the transmission form and the invasive stages of the parasite, its intracellular location, the presence of recently described additional extracellular stages, the host range and target cell tropism, the ability to autoinfection, the nonresponsiveness to anticoccidial drugs, the immune response of the host, and immunochemical and genetic characteristics. These differences have an important impact on the infectivity, the epidemiology, the therapy, and the taxonomy of the parasite. The present article describes the structural analysis of the parasite using light and electron microscopy with an emphasis on structural details unique to C. parvum. 相似文献
8.
Ternary Halides of the A3MX6 Type. II. The System Ag3?xNaxYCl6: Synthesis, Structures, Ionic Conductivity . The influence of the substitution of Ag+ by Na+ ions on the crystal structure and the ionic conductivity of Ag3YCl6 (stuffed LiSbF6-type structure) has been investigated. The system Ag3?xNaxYCl6 forms a complete solid solution. The stuffed LiSbF6-type structure is stable for all compositions. For compounds with Na+ contents of x > 1.67, the cryolite-type structure is observed as the high-temperature form. The transition temperature decreases steadily with increasing Na+ content. The “end member” phase Na3YCl6 transforms at 243 K from the monoclinic cryolite-type structure to the stuffed LiSbF6-type structure (trigonal, R3 ; a = 697.3(1), c = 1 868.4(14) pm, Z = 3; R = 0.094; Rw = 0.069). The crystal structures of Ag1.3Na1.7YCl6 (trigonal, R3 ; a = 691.5(2), c = 1 853.7(6) pm, Z = 3; R = 0.099, Rw = 0.081) and AgNa2YCl6 (trigonal, R3 ; a = 691.7(1), c = 1 853.9(5) pm, Z = 3; R = 0.099, Rw = 0.064) have also been determined. Both chlorides crystallize like Ag3YCl6 and Na3YCl6-I in the stuffed LiSbF6-type structure. The monovalent cations, Ag+ and Na+, are distributed over the five octahedral voids that are occupied by the Ag+ ions alone in Ag3YCl6. The ionic conductivity for compounds within the solid solution Ag3?xNaxYCl6 decreases with increasing Na+ content. The values for Na3YCl6 (σ = 1 · 10?6 Ω?1 cm?1 at T = 500 K) are by 2.5 to 3.5 orders of magnitude smaller than those for Ag3YCl6 (σ = 6 · 10?4 Ω?1 cm?1 at T = 500 K). 相似文献
9.
Let k be a field and let Λ be an indecomposable finite dimensional k-algebra such that there is a stable equivalence of Morita type between Λ and a self-injective split basic Nakayama algebra over k. We show that every indecomposable finitely generated Λ-module V has a universal deformation ring and we describe explicitly as a quotient ring of a power series ring over k in finitely many variables. This result applies in particular to Brauer tree algebras, and hence to p-modular blocks of finite groups with cyclic defect groups. 相似文献
10.