High-spin structure of yrast-band in 78Kr

Lifetime of levels up to 22⁺, have been measured in ⁷⁸Kr and an oblate shape is assigned to the ground state using the CSM and the configuration dependent shell correction calculations. Calculations further show that ⁷⁸Kr is highly γ-soft nucleus. The experimental Q _t values coupled with theoretical calculations indicate an oblate shape for ⁷⁸Kr at low spins and triaxial shape at higher spins     

Infinite-dimensional Lie algebras of generalized Block type

This paper investigates a class of infinite-dimensional Lie algebras over a field of characteristic which are called here Lie algebras of generalized Block type, and which genereralize a class of Lie algebras originally defined by Richard Block. Under certain natural restrictions, this class of Lie algebras is shown to break into five subclasses. One of these subclasses contains all generalized Cartan type Lie algebras and some Lie algebras of generalized Cartan type , and a second one is the class of Lie algebras of type , which were previously defined and studied elsewhere by the authors. The other three types are hybrids of the first two types, and are new.

     

Magnetic properties of Nd3+ in Nd−Ba−Cu−O-compounds

Neutron diffraction, neutron spectroscopy and magnetization measurements have been employed to study the structural, electronic, and magnetic behavior of eleven compounds with the general formula Nd_1+y Ca _v Ba_2–y–v Cu₃O _x (0y0.5; 0v0.25; 6x7). The structure turned out to react to oxygen reduction similar as other 123-compounds, yielding discontinuities close to the metal-insulator-transition and the well-known relations of bond lengths as a function ofT _c. The crystalline electric field (CEF) interaction, splitting the 10-fold degenerate ground-state J-multiplet of the Nd³⁺-ions into five doublet states, was investigated by neutron spectroscopy. The derived CEF parameters have been used to determine changes in the electronic surroundings of the Nd³⁺ ions. In addition, with the help of the CEF parameters the thermodynamic magnetic properties of these compounds were calculated which turn out to be in good agreement with the experimental data.     

Cyclic carbene formation through alkyl migration to molybdenum coordinated isonitrile. Synthesis and X-ray structure of cis-MoI {C(NMe)[CH2]2CH2} (CO)2(η-C5H5). An example of a sterically blocked cis-trans isomerisation for the [Mo(X)(L)(CO)2(η-C5H5)] system

Treatment of Mo(CNMe)(CO)₂(η-C₅H₅)^? with I[CH₂]₃I in tetrahydrofuran affords the carbene complex cis-MoI{C(NMe)[CH₂[CH₂} (CO)₂ (η-C₅H₅), which has been characterised by X-ray crystallography. This complex does not isomerise to the corresponding trans isomer, as might have been expected by analogy with related 2-oxacyclopentylidene systems.     

The determination of zirconium in animal tissues by neutron activation and γ-spectrometry

A neutron activation method has been developed for determining microgram and submicrogram quantities of zirconium in animal tissue. The procedure uses phosphate to aid in the separation of zirconium from interfering radio-isotopes. Tissues are dried, sealed in quartz vials, irradiated at a high flux, and wet-ashed; the zirconium is precipitated as ZrO(H₂PO₄), redissolved, and precipitated as BaZrF₆. This procedure effectively removed interfering radioactive elements. Chemical oxidation and the simple separation procedure were checked by radiotracer experiments, and by processing tissues to which known quantities of zirconium had been added. The detection limit of the method for a 100-h irradiation at 1 × 10¹⁴ n cm^-2 s^-1 followed by radiochemical processing is 10 ng, based on 2 σ counting statistics. The error is estimated to be ± 5–10%.     

Generalized Poisson brackets and lie algebras of type H in characteristic 0

The Lie algebra of Cartan type H which occurs as a subalgebra of the Lie algebra of derivations of the polynomial algebra was generalized by the first author to a class which included a subalgebra of the derivations of the Laurent polynomials . We show in this paper that these generalizations of Cartan type H algebras are isomorphic to certain generalizations of the classical algebra of Poisson brackets, and that it can be generalized further. In turn, these algebras can be recast in a form that is an adaption of a class of Lie algebras of characteristic p that was defined in 1958 be R. Block. A further generalization of these algebras is the main topic of this paper. We show when these algebras are simple, find their derivations, and determine all possible isomorphisms between two of these algebras. Received December 20, 1996; in final form September 15, 1997     

Routine analysis by high precision gas chromatography/mass selective detector/isotope ratio mass spectrometry to 0.1 parts per mil

Stable isotope methods are potentially quite useful for validating natural or enhanced mineral degradation of contaminants. For this reason, a continuous flow gas chromatograph (GC), isotope ratio mass spectrometer (IRMS) has been coupled with a quadrupole mass selective detector (MSD) to allow simultaneous mass spectral and stable carbon isotope ratio data to be obtained from a single chromatographic analysis. This allows the target contaminant and any extra-cellular degradation intermediates to be both qualified and quantified. Previously acceptable limits of precision (0.3 parts per mil) are undesirable given the small fractionation observed during aerobic degradation. To further understand the fate of organic contaminants and to gain information about the metabolic degradative pathway employed by a microorganism, routine isotopic analyses on a range of analytes have been performed. Quantities of sample producing mass-44 ion beam signal (I(44)) of 2 x 10(-10) to 1 x 10(-8) A were analysed. When the IRMS was tuned for high sensitivity, ion source nonlinearities were overcome by peak height correction from an algorithm that was produced using known isotopic standards of varying concentrations. This led to sample accuracy of <0.01 per thousand and sample precision of 0.1 per thousand. Copyright 1999 John Wiley & Sons, Ltd.