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961.
P. Braun-Munzinger D. Miśkowiec A. Drees C. Lourenço 《The European Physical Journal C - Particles and Fields》1998,1(1-2):123-130
Measurements of open charm hadro-production from CERN and Fermilab experiments are reviewed, with particular emphasis on the absolute cross sections and on their A and √s dependences. Differentialp T andx F cross sections calculated with thePythia event generator are found to be in reasonable agreement with recent data. The calculations are scaled to nucleus-nucleus collisions and the expected lepton pair yield is deduced. The charm contribution to the low mass dilepton continuum observed by the CERES experiment is found to be negligible. In particular, it is shown that the observed low mass dilepton excess in S-Au collisions cannot be explained by charm enhancement. 相似文献
962.
Andrzej Maślankiewicz Mirosław Wyszomirski Tadeusz Głowiak Adolf Gogoll 《Journal of chemical crystallography》1991,21(5):559-565
The title compound (C11H11NS2) is monoclinic:P21/c,a=15.200(4),b=14.644(4),c=10.098(3),Z=8. The structure was solved by direct methods, and refined to anR value of 0.047 with 2886 independent reflections. There are two nonequivalent molecules in the unit cell. BothS-methyl groups have different spatial orientation: the-methyl group side-chain is approximately coplanar with the pyridine ring and turned to the ortho-position, but -methyl group side-chain is turned over this ring. Both1H and13C NMR spectra were assigned using 1D and 2D experiments. The NOE measurements are consistent with inter-proton distances from X-ray data.Part XV in the series of Azinyl sulfides. 相似文献
963.
Andrzej Maślankiewicz Tadeusz Głowiak Stanisław Boryczka Mirosław Wyszomirski 《Journal of chemical crystallography》1996,26(11):763-767
The title compound crystallizes in a monoclinic space groupP21/n witha=9.524(3),b=6.782(2),c=26.217(6) Å, =92.52(4)°. The values of the Cl...S and S...S distances are well below the sum of the van der Waals radii of the heteroatoms. Also, the Cl–C–C(S) and (Cl)C–C–S bond angles are below the standard 120°. This indicates a attractive interaction between both pairs ofortho-situated heteroatoms.Part XXXVIII in the Series of Azinyl Sulfides. 相似文献
964.
Tadeusz Glowiak Andrzej Maślankiewicz Miroslaw Wyszomirski Leszek Skrzypek 《Journal of chemical crystallography》1995,25(4):171-176
The title compound I (C10H7NS2) is orthorhombic: Pbca,a=16.223(6),b=15.065(5),c=7.356(4) Å. The conformation of 1,3-dithiol ring is of an envelope-type. A very short intramolecular sulfur-sulfur distance of 2.94 Å was observed. The compoundII (C11H9NS2) is monoclinic: P21/c,a=5.113(2),b=11.978(4),c=16.444(5) Å, =98.00(5) deg. The conformation of the 1,4-dithiin rings is a half-chair. As compared to other 3,4-quinolinediyl bis-sulfides an elongated intramolecular sulfur-sulfur distance of 3.437(4) Å in dihydrodithiinoquinolineII was observed.Part XXXI in the series of Azinyl Sulfides. 相似文献
965.
Andrzej Maślankiewicz Andrzej Zieba Kinga Suwińska 《Journal of chemical crystallography》1998,28(9):701-704
The title compound 1 crystallizes in the monoclinic space group C2/c with a = 16.720(4), b = 8.577(1), c = 15.855(4) Å, and = 98.37(1)°. The thiocarbonyl group C – S bond (1.697(4) Å) is longer than those of typical carbon–sulfur double bonds in thiones. Bond lengths and bond angles in the pyridine ring of the title compound are close to the values found for pyridinium salts. 相似文献
966.
M. Kubicki T. Borowiak H. Chruścicki W. Z. Antkowiak 《Journal of chemical crystallography》1993,23(2):113-118
The crystal structure of 5-hydroxy-9,10-dihydro-4-azaphenanthrene-4-oxide has been determined. The asymmetric unit contains three molecules which slightly differ in their geometries. The 2-phenylpyridine skeleton has been stiffened by linking in the 3,6-positions with the-CH2-CH2-group and by the intramolecular hydrogen bond O-HO. In consequence, a more planar conformation of the molecule is observed in comparison with the conformation of 2-(2-hydroxyphenyl)pyridine-1-oxide where the only flattening factor is the intramolecular hydrogen bond. NMR results confirm that the conformational rigidity persists in solution. 相似文献
967.
968.
969.
Studies on Oxide Catalysts. XLV. Conversion of Aromatics on Dealuminated Zeolites ZSM-5 The catalytic properties of zeolites ZSM-5 dealuminated by hydrochloric acid are investigated in the isomerization of m-Xylene, the disproportionation of toluene and in the alkylation of toluene with methanol. Besides the increase of the Si/Al ratio, the dealumination leads to an inversion of the Si/Al concentration gradient in crystallites, to a shift of acidity spectrum and consequently to a change in catalytic activity and selectivity. 相似文献
970.
M. Wiśniewska V. Bogatyrov I. Ostolska K. Szewczuk-Karpisz K. Terpiłowski A. Nosal-Wiercińska 《Adsorption》2016,22(4-6):417-423
The poly(vinyl alcohol) (PVA) influence on the adsorption and electrokinetic properties of the mixed oxide Mn x O y –SiO2/polymer solution system was examined. Three oxides differing with the Mn x O y contents were applied (0.2; 1 and 3 mmol/g SiO2, respectively). The PVA with the molecular weight 100 kDa was characterized with the acetate groups content equal to 14 %. Adsorption, solid surface charge and zeta potential measurements were made as a function of solution pH (3–10). The obtained results showed that the PVA adsorption amount strongly depends on not only the solution pH, but also manganese oxide content on the mixed oxide surface. The higher solution pH value (or Mn x O y content) is, the higher polymer adsorption is obtained. The PVA addition to the solid suspension causes minimal changes of the mixed oxide surface charge density, whereas the zeta potential of solid particles increases significantly in the polymer presence. 相似文献