Multiqubit spin

It is proposed that the state space of quantum objects with a complicated discrete spectrum be used as a basis for multiqubit recording and processing of information in a quantum computer. As an example, nuclear spin 3/2 is considered. The possibilities of writing and reading two quantum bits of information, preparation of the initial state, and the implementation of the operations “rotation” and “controlled negation,” which are sufficient for constructing complex algorithms, are demonstrated. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 1, 59–63 (10 July 1999)     

Reversible structural phase transition in Ni-Mn-Ga alloys in a magnetic field

In Ni_2+x Mn_1?x Ga shape-memory ferromagnetic alloys with coincident magnetic and structural phase transitions, a reversible structural field-induced phase transition was observed at constant temperature and pressure in magnetic fields of about 10 T. Computational results are in qualitative agreement with experiment.     

Microscopic Examination of the Silicon Surface Subjected to High-Dose Silver Implantation

Technical Physics - Low-energy (E = 30 keV) Ag+ ions have been implanted into single-crystalline Si wafers (c-Si) with an implantation dose varying from 1.25 × 1015 to 1.5 × 1017 ions...     

Measurement of the spectrum of neutrons produced in <Emphasis Type="Italic">pd</Emphasis> collisions at an angle of <Emphasis Type="Italic">θ</Emphasis> = 0° at a proton-beam energy of 1 GeV

The energy spectrum of a neutron beam produced in a thin-wall liquid-deuterium target by a proton beam of energy 1 GeV was measured in a hydrogen bubble chamber by detecting events of the reaction np → ppπ ⁻.     

Structural investigation of non-stoichiometric CuInS<Subscript>2</Subscript> by <Superscript>63</Superscript>Cu and <Superscript>115</Superscript>In nuclear magnetic resonance

Results of studies of non-stoichiometric CuInS₂ semiconductor by ⁶³Cu and ¹¹⁵In nuclear magnetic resonance are presented. It was established that deviation of the composition from stoichiometry causes a quadrupolebroadened region of the NMR spectrum to change most. In this case a central peak whose shape is governed by the chemical shift anisotropy remains unaffected. NMR spectra reveal two types of structural distortions in the nearest surroundings of the In atoms.     

Electrochemical dissolution of Co<Subscript>3</Subscript>O<Subscript>4</Subscript> in acidic solutions

The cyclic voltammetry method was used to study the regularities of the electrochemical behavior of cobalt cobaltite in an acidic medium. It is shown that cathodic reduction of Co₃O₄ in the studied range of potentials of +1.0 to −0.8 V is a multistage process occurring according to the scheme:      

Determination of arsenic in aqueous solutions by no-reference inversion voltammetry

Electrochemical method for arsenic determination at concentrations characteristic of inversion voltammetry was suggested. The method does not require calibration of the measuring instrument against standard solutions or application of the standard-additive technique. The method of no-reference inversion-volammetric determination is based on calculating the arsenic concentration in solution with the use of the preliminarily determined coulometric constant of an electrochemical cell.     

Investigation of the Morphology and Structure of Porous Hybrid 3D Scaffolds Based on Polycaprolactone Involving Silicate-Containing Hydroxyapatite

The results of studies into microporous scaffolds based on polycaprolactone, in particular, involving nanoparticles and microparticles of modified (silicon-containing) hydroxyapatite (hybrid scaffolds) are presented. When hydroxyapatite particles are used during the electrospinning of polymer scaffolds, their porosity is found to increase substantially and a structure with nanofibers and microfibers can be created. X-ray phase analysis demonstrates that the characteristic lines of polycaprolactone and hydroxyapatite exist in the 3D hybrid scaffold structure. According to the data of infrared (IR) spectroscopy of the hydroxyapatitepowder precursor, (SiO₄)^4– ions are embedded in its lattice. The results of studies into the surface wettability indicate that the contact angles of wetting with water are smaller for hybrid scaffolds than for pure polycaprolactone scaffolds. Adhesive and proliferative activity tests of human mesenchymal stem cells (MSCs) performed upon hybrid-scaffold cultivation on the surface, as well as histologic investigations, indicate the high biocompatibility of the samples. On the basis of a polymerase chain reaction, it is revealed that the differentiation of MSCs occurs in the osteogenic direction. On account of a porous structure, hybrid scaffolds can be employed to recover bone-tissue defects.     

X-ray study of the structure of phospholipid monolayers on the water surface

The possibility of laboratory X-ray reflectometry study of the structure of dimyristoyl phosphatidylserine (DMPS) phospholipid monolayers on the water surface in various phase states has been demonstrated.     

Investigation of the external-magnetic-field dependence of polarization transfer in a 8Li-6Li disordered nuclear system

Random walks in disorderedmedia are studied by considering the example of the delocalization of nuclear polarization in an ensemble of ⁸Li beta-active nuclei produced in (n, γ) reactions induced by polarized thermal neutrons in LiF single crystals. The process is initiated by magnetic dipole-dipole interactions. It consists in polarization transfer from a primarily polarized ⁸Li nucleus to the closest (stable) ⁶Li nuclei and in subsequent polarizationmigration over 6Li nuclei, the return of the polarization in question to the ⁸Li nucleus being possible. In order to obtain information about the polarization of ⁸Li nuclei, the asymmetry of beta radiation from them was measured with respect to the external magnetic field H ₀. The process was studied until it reached the diffusion asymptotic regime. The concentration of ⁶Li was varied between 3% and 10%, while the field strength H ₀ was changed from 200 to 1200 G. It is shown that microscopic theory is in satisfactory agreement with the experimental results obtained in the way outlined above. A comparison with the investigation of the mathematically allied process of the Förster electricdipole transfer of localized excitons is performed.