Computer-aided identification of powdered vegetable materials

The use and limitations of the microcomputer as an aid for the analyst in the identification of powdered vegetable materials is presented and suggestions are given for extending the applicability of the method and the programs described.     

Synthesis and reactions of some dihydro and tetrahydro-4H-imidazo[5,4,1-ij]quinoline derivatives

Reaction of phenyl N-(8-quinolinyl)carbamate with sodium borohydride afforded 1,2-dihydro-4H-imidazo-[5,4,1-ij]quinolin-2-one, 2a . The 5,6-double bond of 2a was functionalized by reaction with nitrosyl chloride to give the nitroolefin 4 and by reaction with hypobromous acid to give the trans-bromohydrin 5 . Reaction of 5 with sodium azide led to the rearranged trans-6-azido-5-ol 7 , the structure of which was determined by ¹H nmr studies.     

Zum Aufbau Schlecht geordneter Calciumhydrogensilicate. II. Über eine aus Poly- und Disilicat bestehende Phase

On the Structure of Ill-crystallized Calcium Hydrogen Silicates. II. A Phase Consisting of Poly and Disilicate Both by condensation reactions of a calcium hydrogen disilicate phase [1] under the mother liquid at 80°C and by hydrothermal reactions of lime and silica at 150°C an ill-crystallized calcium hydrogen silicate phase is formed, being built up by nearly equal parts (referred to Si) of poly-and disilicate anions. The CaO content of the phase synthesized at 80°C varies between 1.1 and 2CaO/SiO₂, depending on the Ca(OH)₂ concentration in the mother liquid. In the phase formed at 150°C is CaO/SiO₂ = l.l–l.5. A proposal for the constitution of this phase is given.     

High-resolution field desorption mass spectrometry: Part VII. Explosives and Explosive Mixtures4

Standard explosives and technical mixtures of explosives have been investigated by field desorption mass spectrometry. The compounds investigated gave intense molecular ions or protonated molecules and structurally significant fragmentation. For comparison, the corresponding electron impact and chemical ionization mass spectrometry data are reported. Emission-controlled field desorption, photographic detection, and accurate mass measurements enabled the components of the technical mixtures to be identified. An example of the determination of an additive in a technical product by field desorption mass spectrometry and stable isotope dilution is given. The use of these techniques for quality control of explosives and for forensic investigations appears to be promising.     

Activated alpha-alkyl-alpha-arylacetic acid enantiomers for stereoselective thin-layer chromatographic and high-performance liquid chromatographic determination of chiral amines

The separation of racemic benoxaprofen into the two benoxaprofen enantiomers by preparative high-performance liquid chromatography and the application of the activated enantiomers as derivatization reagents for the simultaneous stereoselective determination of chiral amines in biological material is described. Activated (+)- and (-)-benoxaprofen are both shown to be very sensitive and stable chiral fluorescence markers, applicable to thin-layer chromatography as well as to high-performance liquid chromatography.     

F?llungschromatographie

Ohne Zusammenfassung     

On the dynamics of a quantum system which is classically chaotic

We investigate the dynamics of one anisotropic spin in an external time-dependent magnetic field. The classical dynamics of the system is nonintegrable (and very similar to the standard map). We present results on this model for a quantum spin (i.e. for finite values of the spin lengthS). In particular we discuss the semiclassical regime,S1, using the concept of Wigner functions to define a suitable probability distribution. In regular regions of phase space the time evolution of the probability distribution shows an algebraic decay of correlations as in quantum mechanics. In chaotic regions of phase space it is characterised by a positive Lyapunov exponent which depends onS. In these regions semiclassical trajectories coincide with classical ones fort <₀ where ₀InS.     

Single and double passage AFP NMR/ON studies of54MnNi

High resolution conventional AFP NMR/ON studies provide evidence for very small efg's of predominantly negative sign at the nucleus of the nominal S-state ion⁵⁴Mn in single crystal nickel when the applied field is paralled to the 111 direction. The form of the mid passage signals for opposing sweep directions indicates a unique efg super-imposed upon a random component of comparable magnitude. The advantages of a second analyzing sweep performed during spin lattice relaxation of a conventional post-passage AFP NMR/ON sweep are demonstrated.