Cascaded optical field enhancement in composite plasmonic nanostructures

We present composite plasmonic nanostructures designed to achieve cascaded enhancement of electromagnetic fields at optical frequencies. Our structures were made with the help of electron-beam lithography and comprise a set of metallic nanodisks placed one above another. The optical properties of reproducible arrays of these structures were studied by using scanning confocal Raman spectroscopy. We show that our composite nanostructures robustly demonstrate dramatic enhancement of the Raman signals when compared to those measured from constituent elements.     

Kinetic energy of an asymmetric rigid body moving around a fixed point: invariant representation in terms of quaternion matrices

The similarity transform and the properties of quaternion matrices are used to derive invariant expressions for the inertia matrix and kinetic energy of an asymmetric rigid body undergoing spatial motion around a fixed point in body-fixed and inertial frames of reference. The elements of the quaternion matrixes are Rodrigues–Hamilton parameters and quasi-velocities     

Registration temperature effect in polymers: Physico-chemical aspects

Registration temperature effect in two different polymers - poly(ethylene terephthalate) (PET) and polypropylene (PP) films - is investigated. Temperature effects on track formation are considered in terms of molecular mobility and relaxation transitions. The track eth rate is measured as a function of irradiation temperature in the range of 77 to 373 K. The obtained results are compared with the radical yields, radiothermoluminescence curves and thermally stimulated currents measured with the aim of detecting changes in the mobility of macromolecules and radiolysis intermediates. It is found that the change of the track etch rate with changing registration temperature correlates with γ- and glass transitions in PP and with β-and glass transitions in PET.     

On the approximation of solutions of stochastic differential inclusions

A sequence of approximating equations is constructed for stochastic differential inclusions, and the properties of the measures corresponding to solutions of the approximating equations are studied for the class of stochastic differential inclusions.Translated fromTeoriya Sluchaínykh Protsessov, Vol. 14, pp. 43–48, 1986.     

Steroids of the spirostan and furostan series from plants of the genus Allium. XXVI. Structure of anzurogenin and anzuroside from the collective fruits of Allium suvorovii and Allium stipitatum

A new steroid glycoside of the spirostan series, anzuroside, has been isolated from the collective fruits of the cocultivatedAllium suvorovii Rgl. andA. stipitatum Rgl. (family Liliaceae, local name “anzur”). Enzymatic cleavage of the glycoside has given the previously undescribed steroid sapogenin anzurogenic C, which has the structure of (24S, 25S)-2α,3β,5,24-tetrahydroxy-5β-spirostan-6-one. Anzuroside is the 24-O-β-D-glucopyranoside of anzurogenin C. Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 505–510, July–August, 1989.     

Inhibition of highly purified porcine kidney Na,K-ATPase by steroid glycosides of the spirostan and furostan series and a study of structure-activity relationships

A comparative investigation has been made of the action of 14 steroid glycosides of the spirostan and furostan series on highly purified Na,K-ATPase from the medullary layer of porcine kidneys (∼90% purity in terms of protein). It has been shown that alliospirosides A, B, and D, isolated from the collective fruit ofAllium sepa L., are capable of inhibiting the activity of the Na,K-ATPase The inhibition of the activity of the transport enzyme by alliospirosides A and B is of the uncompetitive type and by alliospiroside D of the competitive type. It is desirable to test alliospirosides on the intact organism. Institute of Physiology, Academy of Sciences of the Republic of Uzbekistan. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 558–566, July–August, 1993.     

Formation of composite membranes containing hydrophobic polymer layers by electron-beam sputter deposition

The chemical structure and the contact and morphological properties of composite membranes prepared by electron-beam sputter deposition of a polytetrafluoroethylene layer on the surface of track-etched polypropylene membrane have been studied. It has been found that the application of such layers results in bilayer composite membranes with both the layers having hydrophobic properties. It has been shown that an increase in the thickness of the deposited polytetrafluoroethylene layer leads to development of its roughness, resulting in the formation of a polymer with superhydrophobic properties on the surface of the initial membrane.     

Polypropylene track membranes as a promising material for targets with polarized protons

Polypropylene track membranes made by irradiation of polypropylene films with a beam of high-energy heavy ions followed by chemical etching of latent ion tracks are proposed for being used as a polarized target material. To give membranes paramagnetic properties needed for allowing dynamic polarization of nuclei, the nitroxyl radical 2,2,6,6-tetramethylpiperidine-1-oxyl was introduced in the samples by the thermal diffusion technique. Using the electron paramagnetic resonance method, we obtained information on paramagnetic centers in the polymer matrix of the membranes and determined the nitroxyl radical concentration and rotational mobility of the spin probe in them.     

Exchange-induced phase separation in Ni–Cu films

Magneto-structural properties of films of diluted ferromagnetic alloys Ni_xCu_1−x in the concentration range 0.7<x<1.0$0.7<x<1.0$ are studied experimentally. Films deposited by magnetron sputtering show partial phase separation, as evidenced by structural analysis and ferromagnetic resonance measurements. The phase diagram of the Ni_xCu_1−x bulk system is obtained using numerical theoretical analysis of the electronic structure, taking into account the interatomic exchange interactions. The results confirm the experimentally found partial phase separation, explain it as magnetic in origin, and indicate an additional metastable region connected with the ferromagnetic transition in the system.