Orientation-dependent tunneling of electrons between planar cyclic molecules

We have investigated the dependence of the efficiency of electron tunneling between planar cyclic molecules on their mutual orientation. An expression has been obtained for the dependence on orientation of the tunneling probability in terms of the cyclic polyene model. The magnitude of the orientation effect has been estimated for a change in the orientation of the molecules from the face-to-face to the edge-to-edge position.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 222–225, March, 1989.     

Thermo-EMF anisotropy in single crystals of the alloy Cu-15 at. % Al-2 at. % Co,aged with precipitation of nonequiaxial particles of a second phase

We investigated the kinetics of aging of single-crystalline samples of the dispersion-hardening alloy Cu-Al-Co by the method of measuring the thermo-emf. The obtained curves of the thermo-emf versus the aging time in two crystallographic directions 100 and 110 are different. We attribute the observed thermo-emf anisotropy to nonequivalence of the distortions of the matrix lattice around the precipitate formed. We estimate the degree of coherent distortions of the matrix.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 57–61, February, 1992.     

Magnetic and magnetoresistive properties of Gd<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Mn<Subscript>1–<Emphasis Type="Italic">x</Emphasis></Subscript>Se selenides

Gd _x Mn_1–x Se (0 ≤ х ≤ 0.15) solid solutions are synthesized on the basis of manganese monoselenide. Their magnetic and electrical properties are studied in the temperature range of 80–900 K in magnetic fields up to 10 kOe. An FCC lattice with the Fm3m space group and antiferromagnetic ordering of the magnetic moments of manganese ions is found. A monotonic reduction in the Néel temperature and an increase in the effective magnetic moment along with the gadolinium concentration are observed. Anomalies in the temperature dependence of electrical resistivity and a shift in the temperatures of anomalies in a magnetic field are found.     

Influence of positions of boron, carbon, and nitrogen atoms in the FCC lattice of iron on the characteristics of interatomic interaction

A semi-empirical model is proposed for calculating the characteristics of interatomic forces for virtualFeB, FeC, andFeN compounds on the basis of their electronic structure as functions of the positions of interstitial atoms. On the example of these compounds the universal character of the dependence of the bulk modulus of elasticity on the electronic density in the interspherical space found previously derived earlier in the literature for pure base and transition metals has been demonstrated. It has been found that the arrangements ofB, C, andN atoms in the octahedral interstices are energetically more favorable in comparison with their arrangements in the tetrahedral interstices. The influence of individual properties of the interstitial elements on the calculated quantities is analyzed. V. D. Kuznetsov Siberian Physical-Technical Institute at the Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 40–44, April, 1999.     

Analysis of Mechanical and Thermogravimetric Properties of Composite Materials Based on PVA/MWCNT and Styrene-Acrylic Copolymer/MWCNT

Russian Physics Journal - Mechanical and thermogravimetric properties of polymer composite materials with various concentrations of multiwalled carbon nanotubes effectively shielding radiation in...     

Synthesis, morphology and specific magnetization of the electrodeposited Zn-Ni-P thin films on copper substrate from non-cyanide electrolyte

Thin films of Zn-Ni-P on a copper substrate were synthesized by electrodeposition from chloride baths. It was found that the diffraction reflections of the crystal structure of Zn-Ni-P thin layers occur at thicknesses d ≥ 5 µm. The X-ray diffraction studies results confirm the formation in the Zn-Ni-P films of ZnNi₁₀P₃ compound. The morphology of the obtained films was analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS). The films are continuous and have a typical topography with many homogeneous globular features. EDS confirmed the formation of Zn-Ni-P coating only in 2 samples with Zn:Ni:P atomic ratios of 1:8:4 and 4:8:3, respectively. X-ray Photoelectron Spectroscopy (XPS) revealed the chemistry and the thickness of the studied thin films. At room temperature and thickness d ≥ 5 µm the investigated thin layers exhibit high values of the specific magnetizations in the range (25–37) A m² kg^?1, leading to the potential use in devices, appliances and electronics. The Curie temperature values of the synthesized Zn-Ni-P films were determined. It was found that by heating Zn-Ni-P thin layers of thicknesses d ≥ 5 µm up to a temperature T=900 K an interaction was detected with the copper substrate leading to a lower specific magnetization.      

Electronic structure and energy ratios of Ni<Subscript>3</Subscript>Al clusters in TiNi nanoparticles with an impurity Al atom

The scattered-wave method is used to calculate electron spectra of central Ni ₈Ti, Ti₈Ni, and Ti ₈Al nanoclusters in nanoparticles of (Ni ₂₆Ti₆₄) Al₁ and (Ti ₂₆Ni₆₄) Al₁ alloys in the B2 structure. The single Al atom is shown to have a better chance for accommodation on the titanium sublattice because of high binding energy. __________ Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Fizika, No. 10, pp. 67–72, October, 2005.     

Well Solvable Cases of the Quadratic Assignment Problem with Monotone and Bimonotone Matrices

Conditions imposed on the matrices of the Quadratic Assignment Problem (QAP) are derived such that an optimum of the QAP is attained on a given permutation. These conditions describe four new sets of matrices, which, in the general case, are not anti-Monge and Toeplitz matrices that were used for most of the known well solvable special cases of the QAP.