Untersuchung der Adsorption einiger polarer und unpolarer Verbindungen auf Kaolinit und Montmorillonit mittels der Chromatographiemethode

Ohne Zusammenfassung     

The relationship between electronic charges and lengths of σ-bonds

Summary A dependence was shown to exist between the electronic charges and the lengths of -bonds of a saturated carbon atom, which permitted us to explain and to correct the existing data on interatomic distances.     

Gamow-Teller resonance in β+ decay of 147mDy and spin-isospin current renormalization

The total absorption spectrum of γ-rays following β⁺ decay of ^147mDy has been investigated. The decay energy Q_ε = 7.18 (10) MeV and an improved value of half-life $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 55.7 (7)}\text{s}$ are determined. The intensity of the transitions from the isomeric state is 31 (3)%, the internal conversion being included. More than 40% of decays populate ¹⁴⁷Tb levels with the excitation energy E_ex ? 4.4 MeV. The β⁺ strength function S_β⁺ exhibits a pronounced narrow maximum at E_ex = 4.84 MeV and some structure at higher energy. The total probability of ^147mDy β⁺ decay corresponds to the value $\text{log}\text{?t = 3.67 (8)}$.The calculation of S_β carried out in the random-phase approximation gives the correct resonance energy. The coefficient of the spin-isospin current renormalization found from the comparison of the calculated β-decay probability with the experimental one is |;G_A/g_v|; = 0.7±0.1.     

Magnetoresistance hysteresis of bulk textured Bi1.8Pb0.3Sr1.9Ca2Cu3Ox + Ag ceramics and its anisotropy

Magnetoresistance of bulk textured Bi_1.8Pb_0.3Sr_1.9Ca₂Cu₃O_x + Ag ceramics has been studied in the magnetic fields applied parallel and perpendicular to a–b planes of Bi2223 crystallites. Besides well known anisotropy of magnetoresistance of textured superconductors (R_H || c > R_H || a–b), anisotropic hysteresis of R(H) dependences was investigated. Parameters characterizing hysteretic R(H) curves differ for the cases H || c and H || a–b. This behavior is explained within the model of a granular superconductor where the total magnetic induction in the intercrystallite boundaries is superposition of the external field and the magnetic field induced by dipole magnetic moments of neighbor crystallites.     

Microwave-induced giant oscillations of the magnetoconductivity in 2D electronic corbino disks with capacitance contacts

Using Corbino disks with capacitance contacts, the microwave photoconductivity of the 2D electron gas in selectively doped GaAs/AlAs heterostructures has been studied at 4.2 K in magnetic fields up to 0.6 T. The giant oscillations of the magnetoconductivity have been revealed in the samples exposed to microwave radiation at high filling factors similar to those earlier discovered in the 2D Corbino disks with ohmic contacts. The results demonstrate that the presence of ohmic contacts is of no importance for the observation of the microwave-induced giant oscillations of the magnetoconductivity in the 2D electron system.