Thermo-XRD-analysis of Co-, Ni- and Cu-montmorillonite treated with anionic alizarinate

Co- and Ni-montmorillonites adsorb in aqueous suspensions up to 13 mmol alizarinate per 100 g clay, onto the broken-bonds whereas Cu-clay adsorbs up to 25 mmol dye per 100 g clay into the interlayer space. Unloaded Co-, Ni- and Cu-clays and samples loaded with increasing amounts of alizarinate, were gradually heated in air to 360°C and analyzed by X-ray diffraction. All diffractograms were curve-fitted. Fitted diffractograms of non-heated samples, showed two peak components labeled C and D, at<span lang=EN-US style='font-size:10.0pt;font-family:Symbol;mso-bidi-font-family: Symbol;mso-ansi-language:EN-US'>?1.22 and<span lang=EN-US style='font-size:10.0pt;font-family:Symbol;mso-bidi-font-family: Symbol;mso-ansi-language:EN-US'>?1.32 nm, characterizing tactoids with mono- and non-complete bilayers of water, respectively. After heating at 120°C component D decreased or disappeared and two new components A and B appeared at<span lang=EN-US style='font-size:10.0pt;font-family:Symbol;mso-bidi-font-family:Symbol; mso-ansi-language:EN-US'>?0.99 and<span lang=EN-US style='font-size:10.0pt;font-family:Symbol;mso-bidi-font-family: Symbol;mso-ansi-language:EN-US'>?1.08 nm, representing collapsed tactoids and tactoids with interlamellar oxy-cations, respectively. At 250°C, C and D decreased or disappeared but A and B appeared in all fitted diffractograms. Co- and Ni-clay after heating at 360°C did not show C and D. Components A and B proved that these clays collapsed indicating that initially there was no alizarinate in the interlayers. At 360°C, C and D persisted in the fitted-diffractograms of Cu-clay, representing tactoids with interlamellar charcoal formed from the partial oxidation of adsorbed dye initially located in the interlayers.     

Regularity and intersections of bracket powers

Czechoslovak Mathematical Journal - Among reduced Noetherian prime characteristic commutative rings, we prove that a regular ring is precisely that where the finite intersection of ideals commutes...     

The set of mapsF_{a,b} :x \mapsto x + a + \tfrac{b}{{2\pi }} sin(2πx) with any given rotation interval is contractiblewith any given rotation interval is contractible

Consider the two-parameter family of real analytic maps $F_{a,b} :x \mapsto x + a + \tfrac{b}{{2\pi }}$ sin(2πx) which are lifts of degree one endomorphisms of the circle. The purpose of this paper is to provide a proof that for any closed intervalI, the set of mapsF _a,b whose rotation interval isI, form a contractible set.     

Resonant generation of even-order harmonics in metal vapors

Generation of the second- and fourth-order harmonics of laser radiation is reported in Mg vapor at the forbidden 3s ²¹ S _o–4s ¹ S _o transition. The conversion efficiency for the second-order harmonics has been measured to be 10^–2% and for the fourth one 10^–8%.     

Dynamic mechanism of photochemical induction of turing superlattices in the chlorine dioxide-iodine-malonic acid reaction-diffusion system

We study the mechanism of development of superlattice Turing structures from photochemically generated hexagonal patterns of spots with wavelengths several times larger than the characteristic wavelength of the Turing patterns that spontaneously develop in the nonilluminated system. Comparison of the experiment with numerical simulations shows that interaction of the photochemical periodic forcing with the Turing instability results in generation of multiple resonant triplets of wave vectors, which are harmonics of the external forcing. Some of these harmonics are situated within the Turing instability band and are therefore able to maintain their amplitude as the system evolves and after illumination ceases, while photochemically generated harmonics outside the Turing band tend to decay.     

The structure ofO-arylmercury derivatives of dihydroxy-9,10-anthraquinones and their reactions with anions

The structure of mono- and di-O-arylmercury-derivatives of quinizarin (1,4-dihydroxy-9, 10-anthraquinone) and anthrarufin (1,5-dihydroxy-9, 10-anthraquinone) and their reactions with Br^–, Cl^–, OH^–, and^tBuO^– anions in the solid state and in aprotic solvents were examined by vibrational and electron spectroscopy. These reactions result in cleavage of the O-Hg bond. The formation of ions or contact ion pairs depends on the size and nature of the counterion; quinizarin dianions give very strong ion pairs with K⁺ cations, which do not cleave in DMSO. The electronic structure of mono- and dianions of the compounds studied is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2933–2940, December, 1996.