Natural specimen of triple solid solution ettringite–thaumasite–chromate-ettringite

Three natural minerals of ettringite group were investigated by TG to refine their chemical composition. Two samples are ettringite Ca_5.97Mg_0.01Sr_0.02Al_1.99Cr_0.01(SO₄)₃(OH)₁₂·23.7H₂O and bentorite Ca_5.99Mg_0.01Cr_1.95Al_0.01Si_0.03(SO₄)_2.82·(CO₃)_0.20(OH)₁₂·19.4H₂O, but the third one Ca_5.99Na_0.01Al_1.38Si_0.62(SO₄)_2.49·(CrO₄)_0.36·(CO₃)_0.46(OH)₁₂·15.8H₂O has found to be a solid solution among ettringite, thaumasite, and chromate-ettringite, not registered yet as a new mineral species. Similar phase is well known in concrete formed with Cr⁶⁺ admixture, but is found for the first time as a natural compound. X-ray single-crystal investigation allowed us to refine the structure and support substitution (SO₄)^2? ? (CrO₄)^2? in natural minerals of ettringite group.     

Synthesis of H (type 4) trisaccharide,key structural fragment of globo-H and fucosyl-GM1 cancer-associated antigens

A convenient synthesis of Fucα1-2Galβ1-3GalNAcβ-OCH₂CH₂CH₂NH₂ (trisaccharide H type 4) is described. This glycan is the terminal part of glycosphingolipids globo-H and fucosyl-GM1 known as cancer-associated carbohydrate antigens.     

Sterically Hindered o‐Quinone Annulated with Dithiete: A Molecule Comprising Diolate and Dithiolate Coordination Sites

A new stable sterically hindered o‐quinone annelated with a 1,2‐dithiete ring was prepared by using mild conditions. The skeleton of the compound comprises diolate and dithiolate functions that have the potential to bind metals leading to the corresponding complexes. The reactivity of this compound as a ligand with respect to both coordination sites was studied. Reactions with metals indicate that the o‐quinone function is reduced in the first stage to give semiquinonate and catecholate complexes. The dithiolate coordination site was involved in the reaction in a few cases only after diolate was bound. A trinuclear manganese complex with coordination on both sites was obtained and characterized by EPR spectroscopy. The electrochemical study of this quinone fused with dithiete is reported.     

Lattice Boltzmann simulation of two-sided lid-driven flow in a staggered cavity

In this article, the lattice Boltzmann method is employed in order to explore incompressible fluid flow inside a two-sided lid-driven staggered cavity. Results of the lattice Boltzmann simulation for antiparallel motion of lids are compared with the data from existing literature. For parallel motion of lids, the characteristics of flow pattern for a variety of Re numbers (50–3200) are presented. An asymmetric steady-state flow pattern for parallel motion of lids is obtained.     

Reaction of Red Phosphorus and Phosphine with Aryl(Hetaryl)Ethenes and -Ethynes

Abstract

Nucleophilic addition of phosphide anions generated from phosphorus red or phosphine to ethenes and ethynes in the presence of super bases to afford organylphosphines and -oxides has been performed.     

Electrochemical performance of lithium titanate anode fabricated using a water-based binder

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Stable blow-up dynamics in the -critical and -supercritical generalized Hartree equation

We study stable blow-up dynamics in the generalized Hartree equation with radial symmetry, which is a Schrödinger-type equation with a nonlocal, convolution-type nonlinearity: First, we consider the -critical case in dimensions and obtain that a generic blow-up has a self-similar structure and exhibits not only the square root blowup rate , but also the log-log correction (via asymptotic analysis and functional fitting), thus, behaving similarly to the stable blow-up regime in the -critical nonlinear Schrödinger equation. In this setting, we also study blow-up profiles and show that generic blow-up solutions converge to the rescaled , a ground state solution of the elliptic equation . We also consider the -supercritical case in dimensions . We derive the profile equation for the self-similar blow-up and establish the existence and local uniqueness of its solutions. As in the NLS -supercritical regime, the profile equation exhibits branches of nonoscillating, polynomially decaying (multi-bump) solutions. A numerical scheme of putting constraints into solving the corresponding ordinary differential equation is applied during the process of finding the multi-bump solutions. Direct numerical simulation of solutions to the generalized Hartree equation by the dynamic rescaling method indicates that the is the profile for the stable blow-up. In this supercritical case, we obtain the blow-up rate without any correction. This blow-up happens at the focusing level , and thus, numerically observable (unlike the -critical case). In summary, we find that the results are similar to the behavior of stable self-similar blowup solutions in the corresponding settings for the nonlinear Schrödinger equation. Consequently, one may expect that the form of the nonlinearity in the Schrödinger-type equations is not essential in the stable formation of singularities.