Synthesis and Ritter Reaction of 2-Ethynyladamantan-2-ol

The reaction of adamantan-2-one with lithium acetylide gave 2-ethynyladamantan-2-ol. The latter reacted with acetonitrile in the presence of sulfuric acid through formation of an intermediate classical carbocation, leading to 2-acetylamino-2-ethynyladamantane and 1-acetylamino-2-acetyladamantane at a ratio of 20:1.     

Yurii Pavlovich Popov February 13, 1928–February 24, 2005 (On the 80th anniversary of his birth)

The scientific biography of the distinguished physicist experimentalist and prominent expert in the field of neutron nuclear physics Yurii Pavlovich Popov (13.02.1928–24.02.2005) is presented, including his work at Lebedev Physical Institute, AS USSR and the Joint Institute for Nuclear Research. Yu.P. Popov was a member of the editorial board of the journal Physics of Particles and Nuclei from 1971 to the end of his life.     

Magnetization and specific heat of DyFe3(BO3)4 single crystal

We present thermodynamic and magnetic studies of single crystalline DyFe₃(BO₃)₄. The data indicate an easy axis antiferromagnetic order below T_N~ 38 K which we attribute to the Fe subsystem. The Dy subsystem remains paramagnetic down to the lowest investigated temperatures of 2 K, but it is polarized by the Fe spins due to a f-d interaction. External magnetic field leads to a spin-flop transition in the iron subsystem as well as to superposed magnetization in the Dy subsystem. The repopulation of two low-lying Kramers doublets in Dy³⁺ ions results in well defined Schottky anomalies in specific heat and magnetization.     

Inverse problem for Euler-Poisson-Darboux abstract differential equation

For the nonhomogeneous Euler-Poisson-Darboux equation in a Banach space, we consider the problem of determination of a parameter on the right-hand side of the equation by the excessive final condition. This problem can be reduced to the inversion of some operator represented in a suitable form and related to the operator solving the Cauchy problem for the homogeneous Euler-Poisson-Darboux equation. As the final result, we show that the solvability of the problem considered depends on the distribution of zeroes of some analytic function. In addition, we give a simple sufficient condition ensuring the unique solvability of the problem. __________ Translated from Sovremennaya Matematika. Fundamental’nye Napravleniya (Contemporary Mathematics. Fundamental Directions), Vol. 15, Differential and Functional Differential Equations. Part 1, 2006.     

Transformation of the Phase Composition and the Mechanism of Transition Region Structuring in a Ferrite-Pearlite Steel Subjected to Thermal-Cycling Borating

The structure and diffusion borating processes of 10-grade ferrite-pearlite steel subjected to thermal cycling are examined. Investigations are carried out by the methods of optical and electron diffraction microscopy and x-ray structural analysis. The actual pattern of the borated material surface structure is shown to be more complicated than that described in previous investigations. It is established that the transition region must be called carboboride.     

Determining electronic-band moments for complex molecular spectra

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 50, No. 4, pp. 631–639, April, 1989.     

High-pressure phases in the GaSb-Mn system

The effect of high pressure (6 GPa) on the formation of new phases in a polycrystalline mixture GaSb: Mn = 1: 1 upon heating was studied. Sphalerite-type solid solutions with a small amount of Mn form at temperatures below 520–600 K. At higher temperatures, new crystalline GaSbMn phases are synthesized: a phase with a simple cubic structure with a lattice parameter a = 2.946 ± 0.001 Å (at 620–670 K) and a phase with a tetragonal CuAl₂-type structure (space group I4/mcm) with lattice parameters a = 6.426 ± 0.004 Å and c = 5.349 ± 0.004 Å (at 690–870 K). These new phases are metastable under normal conditions and have magnetic properties. The structure, conductivity, and thermal stability of the synthesized phases are investigated, and the products of decomposition of these new phases upon annealing are analyzed.     

Influence of the diameter of monolithic capillary columns on their gas chromatography characteristics

Divinylbenzene polymer monolithic capillary columns were prepared on the basis of capillaries 0.01 to 0.53 mm in diameter. Separation properties of the columns were investigated with the use of a test mixture of light hydrocarbons. The permeability and C parameter in the Van Deemter equation were determined for all the columns. For the most part, the columns had similar characteristics: permeability was in the range (2.2 ± 0.2) × 10^?9 cm², with parameter C in the range (0.7 ± 0.2) × 10^?3 s (with n-butane as a sorbate). It was thus established that capillary diameter has only a slight effect on the efficiency of monolithic capillary columns (unlike packed capillary columns and microcolumns, whose properties, according to the literature data, depend strongly on the column diameter). The difference in properties between the narrowest monolithic column (capillary diameter 0.01 mm) and the others is explained by column overloading.