Molecular and conformational properties of comb-like polymers with ionically bound side chains studied in organic solvent

Conformational and dynamo-optical properties of a homologous series of poly(cetyltrimethylammonium 2-acrylamido-2-methylpropane sulfonates) with molecular masses ranging from 80 to 700?kDa were studied in chloroform solutions by viscometry, dynamic light scattering, sedimentation, and flow birefringence. The Mark–Kuhn–Houwink Equations for this polymer in chloroform were obtained; the values of hydrodynamic diameter and the Kuhn segment length as well as the value of intrinsic anisotropy of polarizability of the monomer unit were defined.     

Laser vibrometry based on analysis of the speckle pattern from a remote object

A novel technique is represented that allows one to measure vibrations from a distant object with micron and sub-micron amplitudes in real time.     

A question about pro-p-groups of cohomological dimension 2

The following assertion is proved: if the pro-p-group G has cohomological dimension 2 and contains an open subgroup different from G with zero Schur multipliers, then the quotient group by the commutator subgroup G/(G,G) is infinite. In particular, a pro-p-group of strict cohomological dimension 2 is infinite modulo its commutator-group.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 57, p. 170, 1976.     

Electron spin echo envelope modulation of trapped radicals in disordered systems: nitrogen modulation from isotopically substituted chlorophyll a cations

The electron spin echo envelope modulation of the chlorophyll a radical cation has been examined for radicals containing ¹⁴N and ¹⁵N. The modulation is found to be due primarily to the nitrogen nuclei in the heterocycle and the nuclear quadrupole interaction plays a large part in determining the modulation from ¹⁴N. The modulation from ¹⁵N allows limits to be set on the isotropic and anisotropic hyperfine interactions.     

Observation of the transverse optical plasmon in SmLa0.8Sr0.2CuO4-delta

We present microwave and infrared measurements on SmLa0.8Sr0.2CuO4-delta, which are direct evidence for the existence of a transverse optical plasma mode, observed as a peak in the c-axis optical conductivity. This mode appears as a consequence of the existence of two different intrinsic Josephson couplings between the CuO2 layers, one with a Sm2O2 block layer, and the other one with a (La,Sr)2O2-delta block layer. From the frequencies and the intensities of the collective modes we determine the value of the compressibility of the two dimensional electron fluid in the copper oxygen planes.