A monopole mass filter with a hyperbolic V-shaped electrode

In this article we compare the classical monopole mass filter of von Zahn and the monopole mass filter with a hyperbolic V-shaped electrode. The experimental results and those of computer simulation for both mass spectrometers are presented. We show that the replacement of a conventional 90 degrees V-shaped electrode by an electrode with a hyperbolic profile substantially improves the peak shape of any given mass, and increases the mass resolution by a factor of 3-4 and the abundance sensitivity by a factor of 100. The potential of high analytical performance combined with electroforming techniques for electrode manufacture indicate future practical uses of such instruments. Copyright 1999 John Wiley & Sons, Ltd.     

Regioselective [6π+2π] cycloaddition of 1,2-dienes to 7-substituted 1,3,5-cycloheptatrienes catalyzed by Ti(acac)2Cl2—Et2AlCl

A reaction of 7-alkyl-, 7-allyl-, 7-phenyl-1,3,5-cycloheptatrienes with 1,2-dienes in the presence of the two-component catalytic system Ti(acac)₂Cl₂—Et₂AlCl, which led to the formation of practically important substituted endo-bicyclo[4.2.1]nona-2,4-dienes in up to 90% yields, was accomplished for the first time.     

Optical characterization of thermal-stress induced by spin waves in thin-film ferrimagnetic structures

It is shown that intense spin-dipole waves (SDWs) excited in thin yttrium iron garnet (YIG) films induce an in-plane thermal stress (σ) of 1-2 MPa in a YIG/GGG structure (where GGG is gadolinium gallium garnet). In YIG/GGG with normal magnetization, σ shifts its ferromagnetic resonance frequency by ≈1 MHz, which is comparable to the linewidth of the absorption curve of YIG/GGG resonators. The effect was characterized by an optical technique that detects σ in the GGG substrate. It was also demonstrated that this effect can be used for the optical-microwave spectroscopy of spin waves in thin ferromagnetic films, by using thermal mapping of SDWs in the substrate. We have shown that this opens up the possibility of determining the contribution of the two-particle magneto-elastic interaction to the microwave heating of the sample.     

Justification of the Kirchhoff hypotheses and error estimation for two-dimensional models of anisotropic and inhomogeneous plates, including laminated plates

Asymptotic analysis of the problem describing deformation ofa thin cylindrical plate with clamped lateral side is performed.The problem is considered under the most general statement withthe plate being laminated and consisting of an arbitrary numberof nonhomogeneous and anisotropic (21 elastic moduli) layers.Explicit integral representations of the differential operatorswhich form the two-dimensional model of the plate are derived.In the case when the elastic moduli of each of the layers areconstant, these integral representations turn into algebraicones. The asymptotic procedure is justified with the help ofa weighted inequality of Korn's type. The error estimates obtainedgive a rigorous mathematical proof of both of Kirchhoff's hypotheses(kinematic and static) and shed light on the well-known intrinsicinconsistency of two of the hypotheses.     

Influence of europium nanostructure size on the emission of KBr:Eu^{2 + }

The shape and size of nanostructures formed by the precipitation of europium ions in KBr single crystal has been analyzed using optical absorption (OA), luminescence (LM) and atomic force microscopy (AFM). This work reports a relationship between the emission band peak (EBP) and the nanostructure size. The shift of the t_2g absorption band towards longer wavelengths and a larger 10 Dq value reveals the growth of the nanostructures (NS). The AFM images show that the precipitates have circular shape and ～ 20 to 400 nm diameter according to the position of EBP at around 428–433 nm. The AFM technique allowed us to relate the shape and size of the nanostructures with our previous research by OA and LM. To our knowledge, the topography of europium ions forming NS of different diameter is observed for first time.     

Determination of the element distribution in films deposited using the plasma focus facility by Rutherford backscattering

The C, Cu and W element profiles in films deposited using a plasma focus facility are studied by the Rutherford backscattering of 2-MeV He⁺ ions. The films are deposited onto glass substrates in Ar plasmaforming gas. The element profiles are found to depend significantly on the kinetic energy of particles. The penetration depth of particles with the velocity ~10⁵ m/s is about 1.5 μm. The corresponding element profiles showing the distribution of elements over the thickness of the glass are non-linear. For each element, the maximum layer depth is observed under the glass surface. The formation of Cu, W and C layers under the glass surface and their overlapping is a feature of films deposited using the plasma focus facility. Such an arrangement of layers evidences the significant difference between this method of film deposition and conventional techniques at low rates of atom deposition, as well as diffusion-based methods. The obtained films are found to have dielectric properties.     

Observation of indirect parallel pumping of magneto-elastic modes in layered YIG/GGG structures

In this work we report new experimental results on nonlinear excitation of magnetoelastic (ME) modes in layered YIG/GGG waveguide structures at GHz frequencies, obtained by a guided-wave light scattering technique. It is shown that the fundamental spin-dipole wave (SDW) mode induces a secondary microwave field at double frequency that can efficiently excite shear elastic modes of the structure. The distinctive feature of a mechanism for ME coupling proposed is that it is free from the selection rules and provides continuous excitation of elastic modes within a wide frequency range by means of the standard microstripe line excitation system.     

On the relation of periodic acoustic emission pulses to slow solitary elastic waves (SSEW): Experiments with radiation-damaged glass in liquids

The periodicity (to 20 hours) of acoustic emission signals from radiation-damaged glass placed into liquid is detected. It is assumed that this periodicity is caused by slow solitary elastic waves (SSEW) with discrete velocities, which arise under experimental conditions. (SSEW were discovered and studied at the Lebedev Physical Institute since 1992.)