Weak descartes systems in generalized spline spaces

A class of generalized spline spaces is introduced for which a basis of functions with local support is constructed by using a recursion relation. It is shown that this basis forms a weak Descartes system. Moreover, an interpolation property is given.     

An investigation into the role of metastable argon atoms in the afterglow plasma of a low pressure discharge

An investigation into the behaviour of metastable argon atoms in a low pressure (250 Pa) pulsed electrical discharge was undertaken in an effort to find the cause of the persisting emission from sputtered metal atoms in the afterglow of an atomic fluorimeter. Results obtained by time-resolved emission and absorption measurements of several argon and copper spectral lines indicate that low energy electrons in the afterglow are converted to high energy electrons via the recombination of electrons with argon ions and the subsequent collisions of pairs of metastable argon atoms. The high energy electrons excite the sputtered metal atoms to give rise to a slow decaying emission tail in the afterglow. A probable change in the electron energy distribution in the afterglow may also have an effect on the observed emission. This phenomenon may be reduced by the use of a suitable quenching gas.     

Displacement-cyclization reactions of mono-substituted hydrazines with chloronitrobenzenes and chloronitropyrimidines. New routes to 8-azapurine and benzopyrazole derivatives

Reactions of different chloronitrobenzenes and chloronitropyrimidines with monosubstituted hydrazines, R-NHNH₂, where R is methyl, carbomethoxy and phenyl, are described. The reactivity of these hydrazines in displacement-ortho substituent cyclizations varies substantially, depending on the nature of the aromatic substrate and the hydrazine R group. New routes to 8-azapurine and benzopyrazole derivatives are decribed.     

The total synthesis of (−)-mesembranone

Elaboration of the novel chiral amide acetal (S)-$\text{4}$, constitutes the first total synthesis of natural (?)-mesembranone.     

A study of the second excited state of8Be by the10B(d,α2)8Be-reaction

The second excited state of⁸Be has been studied by analysis of the coincidence spectra of the reaction¹⁰B(d, α)2α forE _d =1.0-2.0 MeV. The excitation energy was found to be 12.0±0.4 MeV, and the reduced width 0.85±0.12 MeV. Differential crosssections of the (d, α ₂)-reaction were deduced.     

Large transverse momentum jets in high-energy proton-proton collisions

We present a study of pp collisions producing large transverse momentum π⁰'s. The data collected at c.m. energies √s=52.4 and 62.7 GeV, give evidence for a two-jet structure. The fragmentation of the jets is studied and correlations between the two jets are investigated. Results are compared with e⁺e^? and νp data.     

A study of excited states of5He by the7Li (d, α)5He-reaction

The interactions of deuterons with⁷Li, in which two α-particles and a neutron are produced in the final state are studied atE _d =1.2 MeV. The dual parameter α-α coincidence spectrum was analyzed with a search program. The results indicate two excited states of⁵He: One at excitation energy 2.9±0.1 MeV and with a reduced width of γ²=1.1±0.4 MeV, and the other at 4.8±0.4 MeV, with γ²=0.9±0.4 MeV. No contributions of sequential decay through the 4⁺ state in⁸Be or direct three body decay was observed.     

X-ray laser gain from Bragg reflection in relativistic electronbeam channel radiation systems

The application of distributed feedback by Bragg reflections in electron-beam channeling X-ray lasers is investigated. Expressions for low-threshold gain are derived for this cavity mirror structure in single crystals and are shown to have possible application in reducing beam high-current requirements by many orders of magnitude