Angular distribution of muon pairs produced by negative pions on deuterium and tungsten in terms of coherent states

Recently published data on thep _T dependence of the angular distributions of muon pairs produced in collisions of negative pions with deuterium and tungsten nuclei reveal an unexpected tendency. We show that the quantum statistical approach involving expansions in terms of coherent states leads in this case to an exact, non-perturbative result which in the lowest order approximation describes the observed trends with sufficient accuracy. In this procedure, the non-vanishing correlations between the coordinates and momenta of dimuons play a decisive role.     

Restoration of multiplicity scaling in high energy proton-proton and antiproton-proton collisions

The energy dependent parameter characterizing the leading particle effect allows to restore the scaling in proton-proton and antiproton-proton multiplicity distributions from Serpukhov until highest available CERN \(S \bar ppS\) collider energies. The identification of theoretical second dispersions with the experimental ones represents one of the basic ingredients in the quantum statistical bosonic approach applied in the present contribution. The KNO scaling at the ISR energies as well as the Worblewski relation for the second dispersions at the \(S \bar ppS\) collider energies arise quite naturally; similar phenomena might appear at higher energies too. Some predictions for 2 and 10 TeV cms energies are specified.     

Preparation and thermal decomposition of halogenometallates

Five new derivatives of general formula [Ru(dipy)₃]MCl₄, whereM=Cu(II), Zn(II), Mn(II), Fe(II) and Co(II), and [Ru(dipy)₃][FeCl₄]₂ were synthesized, and their compositions and structures were confirmed by chemical analysis and electron absorptionüspectroscopy. The thermal decompositions of the compounds were studied by thermoanalytical methods. All these complexes decompose upon heating up to 1300 K, with simultaneous loss of organic fragments and structures were confirmed by chemical analysis and electron absorption spectroscopy.The exothermic effects. The residues after heating correspond to RuO₂ and the appropriate M oxides, contaminated in some cases by pure metal.

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Zusammenfassung Fünf neue Komplexverbindungen des Typs [Ru(dipy)₃](MCl₄] (dipy=2,2-Dipyridyl;M=Cu, Zn, Mn, Fe, Co) sowie [Ru(dipy₃](FeCl₄]₂ wurden dargestellt und ihre Zusammensetzung und Struktur durch chemische Analyse und Elektronenspektroskopie bestätigt. Ihre thermische Zersetzung wurde durch simultane TG-DTA untersucht. Alle Komplexverbindungen zersetzen sich beim Erhitzen bis auf 1300 K unter gleichzeitigem Verlust der organischen Komponente und des Cl an die Gasphase. Der thermische Abbau ist von starken exothermen Effekten begleitet. Die Rückstände nach dem Erhitzen enthalten RuO₂ und das jeweilige Metalloxid, in einigen Fällen durch Metall verunreinigt.

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[Ru(dipy)₃]MCl₄, M = , , , , [Ru(dipy)₃][FeCl₄]₂. , . 1300 . . , .

     

Composition and morphology of stack emissions from coal and oil fuelled boilers

Instrumental neutron activation analysis (INAA) together with scanning electron microscopy (SEM) have been used in the study of fly ash from large electric power and heating plants. Two basic kinds of fly ash originating either from brown coal or heavy-oil combustion can be characterized both by morphology and trace element composition. INAA technique used consisted of both short (1 min) and long (2 h) activations to ensure the determination of 30–40 elements in each fly ash sample. The average composition and determination limits obtained by INAA for coal fly ash produced in several electric power plants burning two kinds of brown coal have been compared with those obtained for fly ash originating from heating plants burning heavy-oil. Coal fly ash showed much higher concentrations of many elements especially of Sc. La, Th, Cs, Ce, Sm, Rb and Al in comparison with oil fly ash. On the other hand, the latter contained relatively high concentrations of V and Ni. The results of INAA of fly ash samples can be used for the projection of efficient separating devices and for the evaluation and prediction of contamination levels in the vicinity of large emission sources.     

Investigation of the physico-chemical structure of oxycellulose after storage for two years and determined by derivatograph

The effect of ageing for a period of two years upon chemically pre-oxidized and irradiated cellulose was investigated. Changes in the chemical structure and energy excitation of atomic groups of oxycellulose skeleton were evaluated from the qualitative and quantitative points of view. The numerical interpretation and complex comparison of the quantities (activation energy, energy quantity EW, values of the thermal effect (areas of DTA peaks) and weight losses) of four degradation phases of pyrolysis were employed, when applying the oxidation pyrolysis method with derivatograph.

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Zusammenfassung Die Wirkung einer zweijährigen Alterung von chemisch voroxydierter und bestrahlter Zellulose wurde untersucht. Veränderungen der chemischen Struktur und die energetische Anregung von Atomgruppen des Oxyzellulosegerüsts wurden unter qualitativen und quantitativen Gesichtspunkten studiert. Eine numerische Interpretation und ein komplexer Vergleich der Größen (Aktivierungsenergie, EnergiemengeEW, Werte der thermischen Effekte — DTA-Peakflächen, Gewichtsverluste) von 4 pyrolytischen Abbauphasen wurden vorgenommen, wobei für die oxydative Pyrolyse ein Derivatograph verwendet wurde.

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, , . . , , EW, ( ) .

     

The luminescence efficiency of YAG: Ce phosphors

The luminescence intensity of Yttrium aluminium garnet activated by the Ce³⁺ (YAGCe³⁺) under cathode-ray excitation depends on the preparation method and content of some dopants. Samples containing Fe, Pt, Ir or some colour centre, respectively, show relatively low luminescence. The maximum luminescence intensity was obtained with the Czochralski method grown single crystals in 98% Ar+2% H₂ atmosphere which were sensitized by oxygen annealing followed by treatment at 1500 °C in molybdenum container using a wet hydrogen atmosphere.     

Design and construction of an quasi-adiabatic dissolution calorimeter with a novel dosing apparatus and a low heat capacity

A quasi-adiabatic calorimeter for determining the molar solution enthalpies (Δ_sol H) of non-volatile solids was constructed. The design of the instrument was adjusted to allow the determination of solution enthalpies of small amounts of solids. For that purpose, the novel apparatus for sample dosage with virtually negligible “blank heat” was built. The rather low heat capacity of the calorimeter was achieved by reducing the volume of the reaction cell (20 mL), the dosing unit, and electric elements (the thermistor and the heater). Good thermal isolation of the reaction cell from the surroundings was accomplished by placing the cell into an evacuated polypropylene vessel. A computer program for processing the calorimetric data according to modified Regnault–Pfaundler method was written. The performance of the calorimeter was tested by determining the heats of the reactions serving as thermochemical standards at 25 °C (the dissolution of KCl and NaCl in water and the dissolution of tris(hydroxymethyl)-aminomethane in 0.1 mol dm^?3 HCl(aq)). The obtained data were in very good agreement with the literature values.     

Nanofibers prepared by electrospinning from solutions of biobased polyamide 4

A successful preparation of polyamide 4 nanofibers via electrostatic spinning with diameters close to 100 nm is described. Polyamide 4 was prepared by the anionic ring‐opening polymerization of 2‐pyrrolidone and characterized. The effect of the system parameters (i.e., molar mass of the polymer, the solvent system) and the process parameters (i.e., the electrode‐to‐collector distance) during the electrostatic spinning have been studied. The morphology of the polyamide 4 fiber layers is given except molar mass of the polymer and the concentration of its solution primarily by the conformation of polyamide chains due to polyelectrolyte effect which was confirmed by viscosity measurements. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2203–2210     

SYNTHESIS AND DESULFURATION OF THIANAPHTHEN-3-CARBOXYLIC ACID DERIVATIVES

Abstract

Bis(trimethylsilyl)peroxide (BSPO) can be used for chemo- and stereoselective generation of P=O group by oxygenation of P(III) centre and transformation of P=S and P=Se groups.