Decomposition of tricyclohexylidene peroxide

Conclusions In the thermolysis of tricyclohexylidene peroxide in the liquid phase a dilactone is formed, besides the earlier identified macrocyclic compounds (cyclopentadecane and hexadecanolide), which is the cyclic ester of 1,10-decanedicarboxylic acid and 1,5-pentanediol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 141–144, January, 1982.     

Hydrogenation of single-walled carbon nanotubes

Towards the development of a useful mechanism for hydrogen storage, we have studied the hydrogenation of single-walled carbon nanotubes with atomic hydrogen using core-level photoelectron spectroscopy and x-ray absorption spectroscopy. We find that atomic hydrogen creates C-H bonds with the carbon atoms in the nanotube walls, and such C-H bonds can be completely broken by heating to 600 degrees C. We demonstrate approximately 65 +/- 15 at % hydrogenation of carbon atoms in the single-walled carbon nanotubes, which is equivalent to 5.1 +/- 1.2 wt % hydrogen capacity. We also show that the hydrogenation is a reversible process.     

Magnetic and magnetoelastic properties of the TbMnSi and Tb<Subscript>0.5</Subscript>La<Subscript>0.5</Subscript>MnSi compounds

X-ray diffraction studies showed substitution of nonmagnetic lanthanum for terbium in the TbMnSi polycrystalline compound to initiate a structural transition from a TiNiSi-type orthorhombic structure (for TbMnSi) to a CeFeSi-type tetragonal phase (for Tb_0.5La_0.5MnSi). Magnetic measurements (of the magnetization, magnetostriction, thermal expansion) performed on Tb_0.5La_0.5MnSi revealed a change in the character of magnetic ordering, the appearance of a ferromagnetic component in the Mn magnetic moment, a strong increase in magnetization as compared to TbMnSi, and the appearance of a spontaneous magnetic moment. Insertion of the lanthanum ion onto the rare-earth sublattice of TbMnSi brings about a change in the unit cell size and, hence, in the Mn-Mn, Mn-Si, and R-Mn interatomic distances, which causes, in turn, a change in the character of exchange interactions in Tb_0.5La_0.5MnSi and the formation of a complex magnetic structure.     

Concept of “broadening” of a Mössbauer γ photon

The previously found anomalies of radioactive decay of Mössbauer isotopes have been successively interpreted on the basis of the model of a “wave field” in a source saturated with its own decay products.     

New type of biosensor based on magnetic nanoparticle detection

A new type of biosensor has been developed based on detection of nanosized superparamagnetic particles that serve as labels in bioreactions. The method is based on non-linear magnetic material detection by a magnetic field having components at two frequencies f₁ and f₂. The response is measured at the combinatorial frequencies f_i=mf₁+nf₂, where m and n are integers, e.g., f_i=f₁±2f₂. Several highly sensitive readers of superparamagnetic particles have been designed and used for development of various formats of immunoassays, including those compatible with immunoconcentration and magnetic enrichment of antigens.     

Photoluminescence kinetics of wurtzite GaN quantum dots in an AlN matrix

The photoluminescence (PL) of GaN quantum dots in an AlN matrix is studied. It is found that the maximum of the PL line does not shift when the laser excitation power varies. The transient PL spectra indicate that the quenching kinetics is nonexponential and the quenching law depends on the spectral range. The experimental data are explained in the framework of a model taking into account the strong built-in electric field in wurtzite structures and the transport of charge carriers between them.