Discontinuous solutions in the theory of plasticity

Translated from Prikladnaya Mekhanika, Vol. 32, No. 7, pp. 65–68, July, 1996.     

Design of Stereogenic-at-Iron Catalysts with a (3+2+1)-Ligand Sphere

A stereogenic-at-iron(II) catalyst scaffold is introduced which contains one coordinated meridional tridentate imidazolidin-2-ylidene-functionalized 2,2′-bipyridine, one bidentate pyrazolylpyridine, and one monodentate acetonitrile ligand. This (3+2+1)-coordination sphere implements a stereogenic iron center. A carbon stereocenter in the N-heterocyclic carbene moiety controls the absolute metal-centered configuration. The bench-stable diamagnetic iron(II) complexes can be synthesized in a highly diastereoselective fashion from iron dibromide in an efficient one-pot coordination reaction. The obtained enantiopure complexes were applied as chiral catalysts in the ring contraction of an isoxazole to a chiral 2H-azirine (quantitative yields, up to 90 : 10 er).     

Relations of the theory of translational perfectly plastic anisotropy in the case of plane deformation

Relations of the theory of translational anisotropy in the case of plane deformation are considered. Some properties of solutions of the original equations are established. The equations for characteristics and some relations along the characteristics are determined.     

Helium diffusion in aqueous sodium chloride solution at high pressures

A molecular dynamic investigation of self-diffusion coefficients of helium and water in aqueous NaCl solution is performed. To understand the nonlinear behavior of the self-diffusion coefficients, a number of structural characteristics (radial distribution functions, hydrogen bond network topology) are calculated. The electrolyte concentration range is discussed in which a local increase in helium self-diffusion coefficient is observed. It is shown that this behavior is caused by a breakdown of the network of hydrogen bonds due to competition between ion positions in the states of solvent-separated and contact pairs.     

Optical-pyrometric diagnostics of the state of silicon during nanopulsed laser irradiation

The dynamics of the reflectivity at ?? = 0.53 ??m and the IR radiation of silicon in the wavelength range 0.9?C1.2 ??m is studied under the action of nanosecond ruby laser radiation pulses. When radiation energy density W is lower than the threshold of laser-induced melting of the surface of a semiconductor crystal, the major contribution to the IR radiation emitted by this crystal is made by edge photoluminescence. As the melting threshold is exceeded, the nanosecond dynamics of the detected IR radiation changes from photoluminescence to the thermal radiation of the forming Si phase melt with a high reflectivity. The results of pyrometric measurements of the peak melt surface temperature as a function of W obtained at an effective wavelength ?? _e = 1.04 ??m of the detected IR radiation agree with the data of analogous measurements performed at ?? _e = 0.53 and 0.86 ??m.     

Solubility of Double Alkali Metal (Na, K) Rare-Earth (La, Ce) Sulfates in Sulfuric-Phosphoric Acid Solutions at 20°C

The dependence of the solubility of NaLa(SO₄)₂·H₂O, NaCe(SO₄)₂·H₂O, KLa(SO₄)₂·H₂O, and KCe(SO₄)₂·H₂O on the concentration of acids in sulfuric, phosphoric, and sulfuric-phosphoric acid solutions containing up to 36 wt % H₂SO₄ and 33.12 g l_-1 H₃PO₄ was studied at 20°C.