A neuro-fuzzy system for X-ray spectra interpretation

A decision scheme for the interpretation of spectra from wavelength dispersive X-ray fluorescence spectrometry is described that encompasses elements from three areas of artificial intelligence: fuzzy logic, rule based expert systems and neural net technology.After transforming the recorded spectra to line spectra by appropriate background correction a reasoning scheme is applied that takes into account not only the observed spectra, but also the recording conditions and prior spectroscopic information regarding the relative emission probabilities and the usefulness of the different lines for the purpose of element identification. The latter is done on the basis of a previously described scheme to compute conditional a posteriori Bayes probabilities for a mean matrix. These different pieces of information are then assembled into a battery of fuzzy rules. The importance of the rules as well as the importance of the X-ray lines is determined in a training process, similar to the one in a feedforward back-propagation network.To further stabilize the results this network is pruned in a second training cycle. This, however, had little effect on the quality of interpretation.The advantages of this approach to the interpretation of X-ray spectra over older ones are numerous: the system adapts itself to better interpret spectra that are of greater importance to a laboratory as these are better represented in the training set; the fuzzy logic is capable of working with incomplete and uncertain knowledge, and the neural network results based on these fuzzy rules is readily interpretable by the X-ray spectroscopist as every rule can be expressed also in natural language as in any classical rule based system.On leave from Silesian University, Katowice, Poland     

Comparison of the Dynamics of Water Molecules in Crystals of Proton-Ordered Ice IX and Its Proton-Disordered Analog III

A computer simulation of proton-ordered ice IX and its proton-disordered analog III (768 molecules, 90 K) was carried out by the molecular dynamics method using Poltev–Malenkov's potential. For ice IX, the differences in the dynamic characteristics of molecules with O(1) and O(2) are much wider than those in the case of ice III. The libration spectrum of ice IX has a number of distinct acute peaks, and the spectrum of ice III is strongly smoothed. These peculiarities are explained by the proton ordering of ice IX and disordering of ice III. The latter is responsible for the great differences in the short- and especially long-range environment of water molecules in ice crystals and hence for the presence of many molecules with different dynamic characteristics. Thus averaging over a large number of different vibrational spectra of molecules leads to a smoothed total spectrum in the case of the proton-disordered crystal modification of ice.     

Reexamination of the thermolytic rearrangement of 4-halophenyl azides to 2-aminophenols and other products

Summary The halogenation of derivatives of 2-aminophenol with N-chloro- and N-bromosuccinimides at ambient temperatures in acetic acid was studied. With the necessary compounds available, a reexamination of the thermolytic rearrangement of 2-halophenyl azides to 2-aminophenols and other products was undertaken. It is certain that the rearrangement of 4-halophenyl azides to 2-aminophenols occurs but the products identified in this study differ significantly from those reported previously by Suschitzky et al. (1963, 1966).

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Neuuntersuchung der thermolytischen Umlagerung von 4-Halogenphenylaziden zu 2-Aminophenolen und anderen Produkten

Zusammenfassung Es wurde die Halogenierung von 2-Aminophenol-Derivaten mit N-Chlor- und N-Bromsuccinimid bei Raumtemperatur in Essigsäure untersucht. Mit den zur Verfügung stehenden Verbindungen konnte eine Neuuntersuchung der thermolytischen Umlagerung von 4-Halogenphenylaziden zu 2-Aminophenolen und anderen Produkten unternommen werden. Diese Umlagerung findet sicherlich statt, allerdings differieren die dabei beobachteten Produkte signifikant von denen, die Suschitzky et al. 1963 und 1966 beschrieben.

     

AM1 studies of photoelectron spectra

Five ionization potentials for thesp,ac andsp, sp conformers of (acetylthiomethyl)trifluorosilane MeC(O)SCH₂SiE₃ and six ionization potentials for the same conformers of (benzoylthiomethyl)trifluorosilane PhC(O)CH₂SiF₃ were calculated by the semiempirical AM1 method. The resulting values are in good agreement with the data of photoelectron spectroscopy only for thesp.ac conformers. The structure of the preferred conformer of (acetylthiomethyl)trifluorosilane was confirmed by measurement of its dipole moment in the gas phase. The influence of the long-range inductive effect (field effect) on the energy of nonbonding electrons of the carbonyl oxygen atom in the series of acetic acid derivatives was observed. For Part 9, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 236–241, February, 1998.     

FT-IR and Raman spectroscopic study of hydrated rubidium (cesium) borates and alkali double borates

FT-IR and Raman spectra of five hydrated alkali borates and five hydrated alkali double borates have been recorded at room temperature in the range 400 to 4000 cm⁻¹, and analyzed. Fundamental vibrational modes have been identified and assignments tentatively made in comparison with the work of Janda and Heller, and Li Jun. The text was submitted by the authors in English.     

四种新的水杨醛缩氨基酞菁Schiff碱的合成及光学性质

以四氨基金属酞菁为原料，合成了四种新的Schiff碱C60H36N12O4M(M=Cu，Ni，Zn，Co)，并用质谱、元素分析、红外、紫外对其结构进行了分析和表征．通过荧光光谱对其光学性质进行了研究，四个Schiff碱官能团及中心金属对其光学性质及稳定性有一定的影响．     

Enhancement of electronic excitation energy transfer in the colloidal crystals of colloidal silica suspensions doped with fluorescent dyes

The efficiency of electronic excitation energy transfer from photo-excited rhodamine 110 (Rh110, energy donor) to rhodamine B (RhB, energy acceptor) in an exhaustively deionized colloidal silica suspension has been studied. This colloidal suspension shows Bragg reflection due to the formation of colloidal crystals and the Bragg-peak wavelength is controllable by the volume fraction of the silica spheres. When the Bragg-peak wavelength matches with the fluorescence band of Rh110, a depletion was observed in the Rh110 fluorescence spectrum. This means the fluorescence of Rh110 is partially trapped due to the Bragg reflection inside the crystal lattice. In the coexistence of RhB, the enhancement of RhB fluorescence intensity was observed. These facts clearly indicate the trapped photon energy of Rh110 is efficiently transferred to RhB within the colloidal crystals. The quantitative measurements showed that the enhancement of the transfer efficiency is 20% (or slightly more) in the present experimental conditions.     

唑环取代的俘精酸酐的合成及其光致变色性能的研究

合成了含     

冠醚化二苯甲酮的合成及其光物理行为

本文报道采用在多聚磷酸中酰化的方法,合成了冠醚化二苯甲酮1～8。它们与叔胺类共用可能被用作光引发剂。为此,用紫外光谱详细研究了这些化合物及其络合后的光物理行为。还提及化合物3和4作为紫外吸收剂的可能性。     

Synthetic diamond electrodes: Photoelectrochemical behavior of vacuum-annealed undoped polycrystalline diamond films

The photocurrent and photopotential for undoped polycrystalline diamond film electrodes prepared by chemical vapor deposition and annealed in vacuum at 1500–1640°C are measured. The metal-like samples (annealed at 1630°C) have a negligible photosensitivity. Judging from the positive sign of the photopotential and the cathodic direction of the photocurrent, the material under study formally behaves as a p-type semiconductor. The photoeffects are presumably caused by structure defects, in particular, the dislocations in diamond crystallites formed close to intercrystalline boundaries during the high-temperature annealing.Translated from Elektrokhimiya, Vol. 41, No. 3, 2005, pp. 343–349.Original Russian Text Copyright © 2005 by Pleskov, Krotova, Ralchenko, Khomich, Khmelnitskii.