The systematics of h112 proton alignment in 157, 158, 159Er

Rotational bands have been observed in ^{157, 158, 159}Er to very high spin ($\text{J ～ 41}\text{h}\text{?}$). Upbends are found, due to the alignment of two h_{$\text{11}\text{2}$} protons at $\text{0.40 ?}\text{h}\text{?}\text{ω ? 0.46}\text{MeV}$ in all bands. A systematic shift with neutron number of the band-crossing frequency is observed and is related to a change in quadrupole deformation ?₂.     

Focusing in a largeF-number optical system

The true focal spot of a focusing system may be defined as either the location of the maximum on-axis intensity or the location of the minimum beam diameter that contains a certain fraction of the power. Diffraction causes this true focus to be shifted from the ideal geometrical optics prediction, the effect being greatest at largeF-numbers. Specifically, a theoretical and experimental study is made of the largeF-number focusing properties of a thin lens in contact with a uniformly illuminated aperture. The results are clarified by a comparison to the focal spot shift for a Gaussian beam.     

Untersuchungen über Kohle und Koks

Analytical and Bioanalytical Chemistry -     

Synthesis of Novel Polyphosphate Analogues of Inositol 1,4,5-Trisphosphate

Abstract

The synthesis of novel polyphosphate mimics of inositol 1,4,5-trisphosphate, including ring-contracted and conformationally restricted analogues is reported.     

Crystal and molecular structure at −35°C of (π-cyclobutadiene)dicobalt hexacarbonyl

The structure of cyclobutadienedicobalt hexacarbonyl, (C₄H₄)Co₂(CO)₆, has been determined by single crystal X-ray diffraction techniques with data gathered at ?35°C by counter methods. Crystals form as red prisms in orthorhombic space group Pnma, with lattice parameters (at ?35°C) a = 12.916(3), b = 10.353(2) and c = 9.118(3) Å for a unit cell with four molecules of (C₄H₄)Co₂(CO)₆. The molecules have rigorous C_s symmetry, with a π-cyclobutadiene ring bound to the Co atom of a Co(CO)₂ moiety which, in turn, is linked to a Co(CO)₄ fragment through the metal atoms. Apparently to decrease repulsion between the cyclobutadiene ring and the bulky Co(CO)₄ group, the four-membered ring is tilted, and as a consequence the CoC₄H₄ interaction is unsymmetrical (CoC(ring) = 1.980(3) to 2.048(4) Å). Full-matrix least-squares refinement of the structure has converged with a R index (on |F|) of 0.027 for 1539 symmetry-independent reflections with I_o > 2.0σ(I_o) within the Mo-K_α shell defined by 4° < 2θ < 60°.     

Photoelectron spectra of V3Si,a high Tc superconductor with a 15 structure

We present a high resolution (0.55 eV FWHM) overview of the valence band of V₃Si by X-ray induced photoelectronspectroscopy. A comparison of the spectrum with band structure calculations allows the determination of band energies at points of high symmetry. A new correlation between the core line asymmetry and the superconducting transition temperature has been established for Ti, V and V₃Si.     

The storage of sea-water samples for the determination of dissolved inorganic phosphate

A study has been made of methods of preservation of sea-water samples to be analysed for inorganic phosphate. It is recommended that the filtered samples be treated with 0.7 ml of chloroform per 100 ml of water and stored in the dark in glass bottles. Polyethylene bottles should not be used for water storage since they strongly adsorb phosphate ion.