ππ\pi\pi scattering S wave from the data on the reaction π−p→π0π0n\pi^-p\to\pi^0\pi^0n

The results of the recent experiments on the reaction $\pi^-p\to\pi^0\pi^0n$ performed at KEK, BNL, IHEP, and CERN are analyzed in detail. For the I=0 $\pi\pi$ S wave phase shift $\delta^0_0$ and inelasticity $\eta^0_0$ a new set of data is obtained. Difficulties emerging when using the physical solutions for the $\pi^0\pi^0$ S and D wave amplitudes extracted with the partial wave analyses are discussed. Attention is drawn to the fact that, for the $\pi^0\pi^0$ invariant mass, m, above 1 GeV, the other solutions, in principle, are found to be more preferred. For clarifying the situation and further studying the $f_0(980)$ resonance thorough experimental investigations of the reaction $\pi^-p\to\pi^0\pi^0n$ in the m region near the $K\bar K$ threshold are required.Comment: 17 pages, 5 figure

Conception of New Phase Dislocation-Based Nucleation at Reconstructive Martensitic Transformations

The role of dislocations and the dynamical mechanism controlling the structural reconstruction in the process of nucleation and wave growth of new phase unit crystals at martensitic transformations in metallic systems are discussed. It has been established that near some rectilinear dislocations with lines and Burgers's vectors typical for the original phase, there are areas where an elastically deformed state is characterized by package of particularities unambiguously corresponding to the well definite morphological attribute set (habit, orientation relationship, macroshear) of the martensite crystal. The distinctiveness of these areas for martensite nucleation is caused by character of strains reducing the magnitude of interphase energetic barrier. The elastic model of the dislocation-based nucleation center of martensitic crystal, allowing to select the dislocations being the most probable for nucleation and to make a martensitic crystal with the morphological attribute specific collection corresponding to each a dislocation, has been proposed. Such dislocations for certain Fe-, Cu- and TiNi-based alloys are indicated. New results for titanium nickel are presented in more detail

Synthesis and thermal transformation of a neodymium(III) complex [Nd(HTBA)₂(C₂H₃O₂)(H₂O)₂]·2H₂O to non-centrosymmetric oxosulfate Nd₂O₂SO₄

<div><p>Neodymium complex [Nd(HTBA)₂(C₂H₃O₂)(H₂O)₂]_n·2nH₂O (<b>1</b>) (H₂TBA = 2-thiobarbituric acid, C₄H₄N₂O₂S) has been synthesized in an aqueous solution at 80–90 °C. The crystal structure of <b>1</b> has been determined by the Rietveld method in space group P2₁/n, <i>a</i> = 8.5939(2), <i>b</i> = 22.9953(5), <i>c</i> = 10.1832(2) Å, <i>β</i> = 112.838(1)°, <i>Z</i> = 4, and <i>R</i> = 0.0181. In <b>1,</b> the Nd(III) is coordinated by four μ₂-HTBA^– ions through O, three oxygens from two μ₂-η² : η¹-bridging CH₃COO^– anions, and two terminal waters with a tri-capped trigonal prism structure. The prisms form an edge-contact pair through two O from two acetates. The pairs are connected by HTBA^– and form a 3-D framework. The principle product of thermal decomposition of <b>1</b> at >750 °C is Nd₂O₂SO₄ (<b>2</b>). The crystal structure of <b>2</b> has been obtained in space group I222, <i>a</i> = 4.1199(4), <i>b</i> = 4.2233(4), <i>c</i> = 13.3490(12) Å, <i>Z</i> = 2, and <i>R</i> = 0.0246. The structure is related to an orthorhombic structure type of M₂O₂SO₄ (M = Ln) compounds. In <b>2</b>, the Nd³⁺ is coordinated by six oxygens in a trigonal prism. Each NdO₆ prism links with two SO₄ tetrahedra by nodes, with four other NdO₆ prisms by edges, and with four other NdO₆ prisms by nodes, and the units form the 3-D frame. In the frame, the layers of SO₄ tetrahedra are alternated by two NdO₆ prism layers.</p></div