Mass spectrometric study of aliphatic alpha-carbonyl azides

A series of derivatives of 2-azidoacetic acid and 2-azidoacetone were synthesized and their behaviour under electron ionization conditions was investigated. This paper reports the electron ionization fragmentation mechanisms for five aliphatic alpha-carbonyl azides, which were clarified by accurate mass measurements and B/E linked scans. The substituent influences the abundance and the nature of the ions resulting from the molecular ion fragmentation.     

Bank-Laine functions with sparse zeros

A Bank-Laine function is an entire function satisfying at every zero of . We construct a Bank-Laine function of finite order with arbitrarily sparse zero-sequence. On the other hand, we show that a real sequence of at most order 1, convergence class, cannot be the zero-sequence of a Bank-Laine function of finite order.

     

On differential polynomials, fixpoints and critical values of meromorphic functions

We prove some results concerning functions ? meromorphic of finite lower order in the plane, such that ??″?α(?′)² has few zeros, where α is a constant, using in part new estimates for the multipliers at fixpoints of certain functions. We go on to consider zeros of derivatives and the minimal lower growth of meromorphic functions with finitely many critical values.     

Erkennung des Pikrotoxins

Ohne Zusammenfassung     

Efficient synthesis of (Z)- and (E)-methyl 2-(methoxyimino)-2-phenylacetate

Direct oximation of 2-oxo-2-phenylacetate (3) gave the (Z)-methyl 2-(methoxyimino)-2-phenylacetate (1) in 71% yield, while the E oxime 2 was prepared from 3 in 65% yield via oxime isomerization of 2-(methoxyimino)-2-phenylacetic acid (5). Computational studies suggest that the isomerization of 5 is thermodynamically driven, while the direct oximation of ketoester 3 is kinetically controlled.     

Zero-angle depolarized light scattering of a colloidal polymer

The potential of zero-angle depolarized scattering for measuring the size distributions of optically anisotropic particles is considered. To illustrate the method, an analysis of Fluon, a teflon latex suspension, is presented. Homodyne correlation functions having signal-to-noise characteristics every bit as good as conventional unpolarized finite-angle measurements enabled confident application of a smoothed exponential sampling algorithm to obtain the decay rate distribution, which was converted to a size distribution with certain approximations. The size distribution obtained from light scattering agrees well with that from electron microscopy.     

On the zeros of meromorphic functions of the formf(z)=Σ k=1 ∞ a k/z−z k

We study the zero distribution of meromorphic functions of the formf(z)=Σ _k=1 ^{∞ a} k/z−z _k wherea _k >0. Noting thatf is the complex conjugate of the gradient of a logarithmic potential, our results have application in the study of the equilibrium points of such a potential. Furthermore, answering a question of Hayman, we also show that the derivative of a meromorphic function of order at most one, minimal type has infinitely many zeros. Supported by an NSF grant. Research carried out during a visit to the University of Illinois, funded by an NSF grant. Research carried out at the University of York while serving as a British Science and Engineering Research Council (SERC) fellow. The author gratefully acknowledges the hospitality and support extended to him by the Department of Mathematics.