Experimental results on a search for narrow resonances in e+e- annihilation into hadrons in the mass region 2520–2990 MeV

A search for possible new resonances produced in e⁺e^- annihilation at Adone has been performed in the mass region 2520–2990 MeV. No evidence has been found for new resonances. We obtain an upper limit on the energy integrated resonant cross section of about 6% of the J/ψ (3100) corresponding value.     

States of 74Ge via the (p,p') inelastic scattering at 22 MeV

The ⁷⁴Ge(p, p') inelastic scattering has been studied at 22 MeV with an overall resolution of 10 keV using a tandem Van de Graaff and a split-pole magnetic spectrometer. Angular distributions have been obtained for about 40 levels in ⁷⁴Ge and comparisons with DWBA and CCBA calculations have allowed spin and parity assignments. The presence of an important collective component in the wave functions of many levels is required in order to explain the data. Possible unnatural-parity levels are populated.     

Solution 1h NMR characterization of equilibrium heme orientational disorder with functional consequences in mouse neuroglobin

The solution 1H NMR spectrum of oxidized (met) mouse neuroglobin, metNgb, demonstrates that it is low-spin and hexacoordinate with strong spectral similarities to ferricytochrome b5. The axial ligands are identified as His(F8) and His(E7), with the latter exhibiting an unstrained Fe-His bond. The presence of two sets of resonances is shown to arise from equilibrium heme orientational isomers ( approximately 2:1). The ligation of cyanide is shown to be extraordinarily slow with a factor approximately 2 difference in rate for the two heme orientations. Not only is Ngb the first mamalian globin with equilibrium heme disorder, but the disorder also has additional functional consequences.     

Effect of the Al/Si atomic ratio on surface and structural properties of sol-gel prepared aluminosilicates

A series of aluminosilicates with an Al/Si ratio ranging from 0 to ∞ (0 for pure silica and ∞ for pure alumina) was prepared by sol-gel process and characterized by surface and structure techniques. Aluminum trisecbutoxide and tetramethylorthosilicate were used as precursors for the sol-gel synthesis. The acidic properties of the oxides were studied by determination of the zero point charges, through mass titration method, and, for selected samples, by FT-IR spectroscopy of adsorbed pyridine used as a probe for both Brønsted and Lewis acidity. A dependence of the acidity on the Al/Si atomic ratio was found. According to the X-ray diffraction patterns, all the oxides have an amorphous structure except pure alumina exhibiting a γ-alumina pattern. The surface areas of the mixed oxides increase with increasing amount of alumina and are higher as compared to the individual oxides. The surface elemental distribution and electronic properties were investigated by X-ray photoelectron spectroscopy. According to the results, good agreement between the surface Al/Si atomic ratio and the analytical ratio is obtained.     

A Characterization of the ω-Limit Sets of Interval Maps

Given a continuous interval map f we obtain a characterization of those closed nowhere dense and strongly invariant sets by f that can be -limit sets for such a map.     

Experimental and Theoretical Studies of Two New Trinuclear Ni(II) Asymmetric Salamo-Based Complexes

Russian Journal of General Chemistry - Two new trinuclear Ni(II) complexes, [{Ni(L)(DMF)(μ-OAc)}2Ni] (1) and [{Ni(L)(EtOH)(μ-OAc)}2Ni]·2CH2Cl2 (2), have been successfully synthesized...     

A comprehensive experimental study of the rheological behaviour of HDPE

Die-swell data have been obtained for six high-density-polyethylene (HDPE) samples. The data are presented in the form of generalized relationships taking into account both molecular and operational parameters. Data obtained from annealed samples have been used to calculate the first normal-stress difference by using Tanner's approach. An analytical expression has been found correlating the normal-stress difference with the shear-stress taking into account the molecular characteristics.     

An experimental investigation of the shear behaviour of polyethylenes with different structures

Rheological properties in shear flow are presented for four different polyethylene samples: a high density, a linear low density and two low density polyethylenes manufactured using different techniques. Tests have been performed with the aid of capillary types of instrument equipped with capillaries of various lengths at three different temperatures. End correction factors have been determined and true flow curves obtained. Swelling ratios for both unannealed and annealed samples have been determined as well as the shear rate and shear stress at which irregularities begin. In some cases generalized plots have been prepared and in all cases the rheological response is discussed in terms of molecular characteristics, in particular the average molecular weight, molecular weight distribution and degree of branching.