The use of Zeeman perturbed 14N nuclear quadrupole resonance (NQR) to determine the nu_+ and nu- 14N lines in polycrystalline samples with several nonequivalent nitrogen atoms was investigated. The ▫14N NQR line shift due to a weak external Zeeman magnetic field was calculated, assuming isotropic distribution of EFG tensor directions. We calculated the broad line distribution of the nu+ and nu- line shifts and experimentally confirmed the calculated Zeeman field dependence of singularities (NQR peaks) in cyclotrimethylenetrinitramine (RDX) and aminotetrazole monohydrate (ATMH). The calculated and measured frequency shifts agreed well. The proposed measurement method enabled determination of which 14N NQR lines in ATMH belong to nu+ and which to nu- transitions.
COBISS.SI-ID: 16000089
By measuring the zero-field-cooled and feld-cooled dc magnetic susceptibilities, the ac susceptibility, the magnetization versus the magnetic feld, and the thermoremanent magnetization time decay, we found studied the magnetic properties of FeAl2 and Fe2Al5. FeAl2 undergoes complex two-step magnetic ordering. At T = 32 K, a magnetic phase transition (not yet specified) takes place in which a small fraction of the Fe spins participate, whereas at Tf2 = 12 K, the majority spin fraction undergoes a spin-freezing transition to a spin glass phase. Fe2Al5 undergoes a transition to a spin glass phase at the spin freezing temperature Tf = 3 K, which was not reported previously. The spin glass phase in Fe2Al5 is “soft” and fragile with respect to the external magnetic field and can only be observed in low magnetic fields below 100 Oe.
COBISS.SI-ID: 24856359
Underwater radar was developed that can observe geological structures below the river or lake bottom. Furthermore, it can measure through several meters of water, and detect objects buried on the bottom as well as geological structures. The reflected radar signal was measured up to 5 meters below the lake bottom at the Lake Podpeč near Ljubljana, Slovenia.
COBISS.SI-ID: 24869671