The nature of the intermediate compound formed in the ZnO + H<Subscript>2</Subscript>O<Subscript>2</Subscript> reaction

The properties of the intermediate compound formed on the surface of zinc oxide and partially transferred into the gas phase in the reaction between zinc oxide and hydrogen peroxide vapor were studied. An analysis of the experimental data showed that intermediate compounds could be zinc peroxide and zinc peroxide peroxosolvate.     

The effect of the conditions of the photocatalytic carbonylation of pentane catalyzed by the Rh2Cl2(CO)4-PMe3 system on the yield of C6-aldehyde

The yield of C₆-aldehyde in the photocatalytic system Rh₂Cl₂(CO)₄-PMe₃ passes through a maximum as the CO pressure and PMe₃ concentration increase. The increase in the yield of aldehydes with increasing CO pressure is related to the increase in the carbonylation rate and to the retardation of the photodecomposition of the aldehydes. The rate of the photocatalytic carbonylation of pentane in this system is 20 times higher than in the presence of RhCl(PMe₃)₂(CO).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1013–1015, June, 1994.     

Condensed pyridopyrimidines. 1. Synthesis of new derivatives of pyrano[3′,4′∶5,6]pyrido[2,3-d]pyrimidines

New derivatives of pyrano[3,45,6]pyrido[2,3-d]pyrimidines were synthesized from ethyl 2-amino-7,7-dimethyl-7,8-dihydro-5H-pyrano[4,3-b]pyridine-3-carboxylate.A. L. Mndzhoyan Institute of Fine Organic Chemistry, National Academy of Sciences of the Republic of Armenia, Erevan. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1239–1241, September, 1999.     

Observation of meson central production in baryon exchange processes

The central production of ⁰,f ₂ and ₃ ⁰ mesons is observed for the first time in processes which are originated by ⁺ p reactions proceeding via baryon exchange mechanism. The data come from the CERN WA56 experiment designed to separate the baryon exchange reactions in ⁺ p-collisions at 20 GeV/c. We report on the measured integral and differential cross sections and also give the density matrix elements of the meson resonances observed.     

Synthesis of acetylenic derivatives of 1,4-dioxane

Cyclic ketals — 2,5-dimethyl-2,5-bis(4-penten-2-ynyloxy)-1,4-dioxane and 2,5-dimethyl-2,5-bis(3-phenyl-2-propynyloxy)-1,4-dioxane — were isolated in the reaction of propargyl alcohol with vinyl- and phenylethynylcarbinols in the presence of HgO-BF₃.O(C₂H₅)₂ catalytic system.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1029–1030, August, 1986.     

Generation of urinary steroid profiles in patients with adrenal incidentaloma using gas chromatography–mass spectrometry

A method is developed for the determination of steroid hormones in urine using gas chromatography with mass-spectrometric detection. Sample preparation procedure and the conditions of chromatographic analysis were optimized, and characteristic urinary steroid profiles of patients with adrenocortical cancer were obtained. Criteria for the evaluation of the deficiency of 21-hydroxylase and 11β-hydroxylase in patients with adrenal incidentaloma are proposed.     

Some properties of solutions of a scalar Riccati equation with complex coefficients

We give the definition of normal and limit solutions of the Riccati equation with complex coefficients and study some properties of these solutions. We prove the minimality property of a solution of a system of two linear first-order ordinary differential equations.     

On existence of a universal function for <Emphasis Type="Italic">L</Emphasis> <Superscript> <Emphasis Type="Italic">p</Emphasis> </Superscript>[0, 1] with <Emphasis Type="Italic">p</Emphasis>∈(0, 1)

We show that, for every number p ∈ (0, 1), there is g ∈ L¹[0, 1] (a universal function) that has monotone coefficients c_k(g) and the Fourier–Walsh series convergent to g (in the norm of L¹[0, 1]) such that, for every f ∈ L^p[0, 1], there are numbers δ_k = ±1, 0 and an increasing sequence of positive integers N_q such that the series ∑ _k=0^+∞δ_kc_k(g)W_k (with {W_k} theWalsh system) and the subsequence \(\sigma _{{N_q}}^{\left( \alpha \right)}\), α ∈ (?1, 0), of its Cesáro means converge to f in the metric of L^p[0, 1].     

Structure and energetics of equiatomic K-Cs and Rb-Cs binary clusters

The basin-hopping algorithm combined with the Gupta many-body potential is used to study the structural and energetic properties of (KCs)(n) and (RbCs)(n) bimetallic clusters with N=2n up to 50 atoms. Each binary structure is compared to those of the pure clusters of the same size. For the cluster size N=28 and for the size range of N=34-50, the introduction of K and Rb atoms in the Cs alkali metal cluster results in new ground state structures different from those of the pure elements. In the size range N>/=38 the binary and pure clusters show not only structural differences, but they also display different magic numbers. Most of the magic Rb-Cs and K-Cs clusters possess highly symmetric structures. They belong to a family of pIh structures, where a fivefold pancake is a dominant structural motif. Such geometries have not been reported for alkali binary clusters so far, but have been found for series of binary transition metal clusters with large size mismatch. Moreover, tendency to phase separation (shell-like segregation) is predicted for both K-Cs and Rb-Cs clusters with up to 1000 atoms. Our finding of a surface segregation in Rb-Cs clusters is different from that of theoretical and experimental studies on bulk Rb-Cs alloys where phase separation does not occur.     

10-GHz dispersion-managed soliton fiber-optical parametric oscillator using regenerative mode locking

We demonstrate a regeneratively mode-locked fiber-optical parametric oscillator that utilizes intracavity dispersion compensation to generate pulses at a 10-GHz repetition rate in both soliton and nonsoliton regimes. At the threshold pump power the generated pulses are close to fundamental solitons. At higher pump powers we found a significant deviation of the pulses from the sech2 shape. In addition, the use of an ultralow-jitter self-starting pump-pulse source in a regenerative feedback loop allows for a significant reduction of the signal's timing jitter and amplitude noise.