Characterisation and analysis of micro-contaminants in industrial polymers

Analysis of very small particles can present problems. This paper describes the application of temperature programmed solid insertion probe mass spectrometry (TP-SIP-MS), scanning electron microscopy and SEM X-ray microanalysis to the identification of foreign particles present in an industrial product. The relative advantages and limitations of the techniques are discussed. It is shown that TP-SIP-MS is a powerful tool for such work and complements the use of more conventional microanalytical methods.     

The complete matter sector in a three-generation compactification

We consider a Calabi-Yau compactification paradigm with three light generations and anR-symmetry. From a special form of the Tian-Yau manifold, we also construct a new three-generation model with markedly different phenomenology. Thecomplete spectrum of all light matter fields is obtained in a universal way and moreover in a physically suitable basis, allowing a straightforward analysis of all their couplings. Here we discuss all the renormalizable Yukawa couplings. This computation can equally well be repeated for all compactification models based on Calabi-Yau complete intersections in products of homogeneous spaces.     

THE REACTIONS OF N3P3CL6 AND RELATED COMPOUNDS WITH DIFUNCTIONAL REAGENTS. COMPARISONS AND CONTRASTS

Abstract

The reactions of N₃P₃Cl₆ with a variety of difunctional reagents are discussed. NMR spectroscopic and X-ray crystallographic investigations are presented.     

AN INVESTIGATION OF THE REACTION PRODUCTS OF N3P3CL4(NH2)2 WITH NUCLEOPHILIC REAGENTS. EXAMPLES OF GEMINAL → NON-GEMINAL REARRANGEMENTS

Abstract

Based on its reactions with various nucleophiles both geminal and non-geminal structures have been earlier proposed for N₃P₃Cl₄(NH₂)₂, although its geminal structure is now considered established. The reactions of this compound with alcohols have been investigated and the products examined by NMR spectroscopy and X-ray crystallography. Evidence for both unrearranged as well as geminal → non-geminal rearranged alcoholysis products is presented.     

A sensitivity comparison of three photoacoustic cells containing a single microphone,a differential dual microphone or a cantilever pressure sensor

Three photoacoustic (PA) cells designed for trace-gas sensing were compared by measuring absorption by the P(15) rotational line of the vibrational combination band of acetylene using a distributed-feedback diode laser. Normalised sensitivities were determined for each cell by analysis of the signal to noise ratios of acquired spectra. The first cell was constructed in-house, and contained a single electret microphone held in a stainless steel tube. The second cell was a differential PA cell that contained two microphones housed in identical flow tubes, with one microphone to detect the PA signal and the other to determine background noise levels. The third cell contained a novel cantilever pressure sensor, movement of which was measured by a compact laser interferometer. Normalised sensitivities (2σ) of 3.1×10^-7, 1.7×10^-7 and 2.2×10^-9 cm^-1 W Hz^-1/2, respectively, were obtained. An erbium-doped fibre amplifier was used to amplify the laser power, and a detection limit of 9.8×10¹⁰ molecule cm^-3 was obtained using the cantilever pressure sensor PA cell, with a laser power of 1.17 W. This detection limit corresponded to a mixing ratio of 14.5 parts per billion by volume at 277 mbar. PACS 82.80.Kq; 42.62.Fi; 82.80.Gk     

Geodesies in the Erez-Rosen space-time

We investigate null and time-like geodesics in the Erez-Rosen space-time, that is, in the exterior gravitational field of a mass with quadrupole moment. By using the weak-field approximation of the Erez-Rosen metric, we find the solution of the equation for equatorial time-like geodesics and determine how they differ from the corresponding Schwarzschild geodesies. For the exact form of the Erez-Rosen metric, we only draw some qualitative conclusions about the influence of the quadrupole moment on the path of test particles and on the motion of photons. We derive the relativistic contribution of the quadrupole moment to the perihelion shift and to the precession of the ascending node.     

Gasanalyse

Ohne Zusammenfassung