In the semi-classical approach to the Skyrme model, nuclei are approximated by quantum mechanical states on a finite-dimensional space of field configurations; in zero-mode quantization this space is generated by rotations and isorotations. Here, simulated annealing is used to find the axially symmetric Skyrme configuration which extremizes the zero-mode quantized energy for the nucleon. 相似文献
A comprehensive DTA study is reported of ten polyhydroxy-phenols and eight naphthols and of the correspondingp-phenylazo benzoylchloride,p-nitrobenzoylchloride and 3,5-dinitrobenzoylchloride derivatives, prepared in situ by heating intimate mixtures of phenol and acid chloride in a conventional DTA system. The thermal analysis data and, in particular, the derivative formation temperatures, are interpreted in terms of the inductive, mesomeric and steric effects associated with the phenol and acid chloride and the extent of inter- and intramolecular hydrogen-bonding existing in these systems. The DTA data collectively, provide a comprehensive data base for the identification and characterisation of these phenols via DTA.
Zusammenfassung Dies ist eine umfassende DTA-Untersuchung von zehn Polyhydroxyphenolen und acht Naphtholen sowie der entsprechendenp-Phenylazobenzoylchlorid-,p-Nitrobenzoylchlorid- und 3,5-Dinitrobenzoylchlorid-Derivate, die durch Erhitzen inniger Gemische des jeweiligen Phenoles und Säurechlorides in situ in einem herkömmlichen DTA-Gerät hergestellt wurden. Die bei der Thermoanalyse erhaltenen Angaben, insbesondere die Bildungstemperatur der Derivate wurde bezüglich des induktiven, mesomeren und sterischen Effektes bei Phenol und Säurechlorid sowie der Stärke der in diesem System existierenden inter- und intramolekularen Wasserstoffbrückenbindungen interpretiert. Die Gesamtheit der DTA-Daten bietet eine umfassende Datensammlung für Identifizierung und Charakterisierung dieser Phenole mittels DTA.
X-Ray diffraction, infrared, and raman spectroscopic methods were investigated for the detection of K2SO4 in excess of K2S2O7 in solid solutions.The X-ray diffraction lines of K2SO4 were found to be overlapped by the diffraction pattern of K2S2O7 and infrared studies indicated that K2SO4 absorption bands corresponded to regions of strong absorption in K2S2O7. The detection of sulfate could not be carried out by the X-ray diffraction and infrared methods. However, the raman method indicated that a strong and narrow K2SO4 band at 981 cm?1 could unambiguously be used for the detection of sulfate in solid solutions of K2SO4 in K2S2O7, as pyrosulfate showed no absorption around this band. 相似文献
The preparation of two yttrium 8-hydroxyquinolinates, one by conventional means and the other by precipitation from homogeneous solution, was investigated. Analytical data indicated that the complex prepared conventionally corresponds to Y(C9H6NO)3, and the complex prepared by precipitation from homogeneous solution corresponds to Y(C9H6NO)3·C9H7NO. Thermogravimetric analyses, infrared, ultraviolet-visible and diffuse reflectance spectroscopic studies were carried out on both compounds. They were shown to be very similar structurally. 相似文献
The enthalpy change (303 K) for the standard state solid phase complexation reaction is derived using conventional solution calorimetric techniques (ΔH°R=?82.7±2.0 kJ mol?1. Knowlege of ΔH°R is a necessary pre-requisite for the future derivation of the FeS thermochemical bond energy. 相似文献
Six xanthate derivatives of arsenic(III), antimony(III), and bismuth(III) {(ROCS2)3M; R=methyl, ethyl, isopropyl, n-butyl, cyclohexyl and benzyl} have been prepared and the thermal behaviour investigated by thermogravimetry. A thermal decomposition mechanism for the complexes is proposed on the basis of the thermogravimetric data and mass spectral measurements. 相似文献
The nature of coordination in metal monothiocarbamates is shown to depend on the hardness or softness of the metal ton. Thus,
the monothiocarbamate ion acts as a monodentate ligand with metal-sulphur bending when the metal ion is a soft acid while
it acts as a bidentate ligand when the metal ion is a hard acid; it can exhibit either behaviour when the metal ion is a borderline
acid. In dialkyltin and dialkylmonocholorotin complexes, the monothiocarbamate ion acts as a bidentate ligand with strong
Sn-S bonding while in trialkyl-or triaryl-tin complexes it acts essentially as a monodentate ligand. Thus, R3Sn(I) seems to be a soft or borderline acid while R2Sn(II) is a hard acid. 相似文献
The polarographic behaviour of complexes of the noble metals was studied by oscillographic polarography. A method was developed for the polarographic determination of copper, gold and palladium; silver and nickel do not interfere. Applications to the analysis of dental alloys proved successful. 相似文献
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. 相似文献