Magnetic structure of the random system near the ferro-antiferromagnetic transition

The magnetic structure of the disordered alloy Fe₆₅Ni₂₈Mn₇ was investigated in the temperature 4.2–300 K by the methods: small angle scattering of neutrons, Mössbauer effect, magnetization, magnetic contribution to the thermal coefficient of the thermal expansion, and resistivity. All measurements show that long-range ferromagnetic order appears below T_c ? 160 K. At the same time for T ? 100 K, a dramatic change of magnetic state takes place which is interpreted as the freezing of “spin glass”. An increase of the magnetic contribution to the resistivity with decreasing temperature was also found. This increase was attributed to the existence of poor-bonded magnetic moments of the Kondo-type. A model of the magnetic ground state is proposed which includes the details of magnetic behavior such as long-range ferromagnetic order, spin glass, finite ferro-and antiferromagnetic clusters, and Kondo-type states. A magnetic phase diagram of the system Fe₆₅(Ni_1?xMn_x)₃₅ is also proposed.     

On the variation of physicochemical properties of starch samples treated by microwave radiation

Acid-base properties of potato starch suspensions, unirradiated and exposed to microwave radiation, and also comparative structural and mechanical properties of their cooked gels were studied by the methods of electronic photography of starch grains, direct potentiometry, and potentiometric titration.     

2,5-Dimethylindolo[3,2-b]pyridines and polymethine dyes based on them

Alkylation at the nitrogen atom of the pyrrole ring of 2-methylindolo[3,2-b]-pyridine was studied, and new 2,5-dimethyl-8-R-indolo[3,2-b]pyridines (R=H, Br) were synthesized. The ethiodides of these compounds and their 2--acetanilinovinyl derivatives, in the condensation of which in DMSO in the presence of potassium tert-butoxide symmetrical carbocyanines were synthesized, were obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 391–395, March, 1990.     

Activities of Rybak’s seminar—Workshop on the acoustics of inhomogeneous media in 2007

Acoustical Physics -     

Electrocatalytic oxidation of glucose in a neutral medium on an electrode modified by carboxylated multi-walled carbon nanotubes and by silver and palladium

Russian Chemical Bulletin - Drop deposition of a carboxylated multi-walled carbon nanotube suspension and layer-by-layer electrochemical deposition of silver and palladium were used to modify...     

Andreĭ Viktorovich Gaponov-Grekhov (On his 80th birthday)

Chronicle

Andreĭ Viktorovich Gaponov-Grekhov (On his 80th birthday)     

Samuil Akivovich Rybak (On his 70th birthday)

Chronicle

Samuil Akivovich Rybak (On his 70th birthday)