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A method for diagnostics of chemical compounds based on their spectra in infrared is presented and a C# programme which analyses and indentifies chemical compounds using the above method is described. The overfitting problem in artificial neural networks is also discussed.
In the present review our interest is focused on the hydrogen bonded complexes of tetramethylpyrazine (TMP) with strong proton donors, in particular with chloranilic (CLA) or squaric (H2SQ) acid. The x-ray diffraction studies show that, depending on the proton donor, various assemblies with the acid are formed, e.g. the infinite O-H…N hydrogen bonded chains without proton transfer in the case of the complex with CLA. On the other hand with H2SQ the assemblies of [HSQ]2 2–-2TMPźH+ composition are created, in which the ionized HSQ–1 molecules are present in the form of dimers. These dimers are bound with the TMPźH+ cations on its both sides via the +N-H…O– hydrogen bonds. Picric acid forms with TMP the complex of the 2:1 composition with a double protonated TMP molecule. In the case of HI3 acid the interesting units of the (TMPźH+)2źTMP composition are formed, in which two TMPźH+ cations are coordinated with one TMP molecule through the +N-H…N bridges. In the infrared spectra of the TMP complexes, both with CLA and H2SQ, the similar absorption continua are observed. They can be interpreted in terms of an asymmetric potential for the proton motion, with either the double minimum or the single broad minimum potential for the CLA and H2SQ complexes, respectively. An analysis of the neutron scattering spectra concerns the phenomena of the tunneling splitting, quasielastic neutron scattering (QNS) and inelastic (INS) scattering. In the case of tunneling splitting neat TMP does not show any tunneling transitions in the ěeV energy region, because they are overlapped by the elastic scattering band. In the case of the TMPźCLA complex four tunneling transitions are seen corresponding to the four crystallographically nonequivalent CH3 groups in the TMP molecule. In the spectrum of the complex with squaric acid the observed two transitions are ascribed to the two different CH3 groups. The two remaining CH3 group tunneling transitions are overlapped by the elastic scattering. The measurements in various low temperature ranges yield information about the shape of the CH3 group rotational potential. The shape of the potential is also reflected in the spectra of quasielastic scattering. In particular the temperature dependence of the quasielastic band allows us to find the activation energy for the CH3 rotations. Finally the inelastic neutron scattering spectra are analyzed in the energy range of the CH3 torsional modes (below 200 cm–1 = 25 meV). The analysis shows that for the complexes the torsional vibration frequencies are markedly lower than those for neat TMP. In the case of the TMPźCLA complex frequencies found are particularly low. They are close to the frequencies calculated for the TMP+ cation. A general conclusion can be drawn that in the complexes the CH3 groups behave more loosely than in neat TMP.
Celem przeprowadzonych badań była charakterystyka właściwości fizykochemicznych oraz składu ilościowego i jakościowego związków próchnicznych gleb występujących w rejonie Kłodzka, a zaliczanych obecnie do czarnych ziem. Warunki fizjograficzne na tym obszarze nie wskazują na możliwość przebiegu procesu bagiennego, który warunkuje powstawanie czarnych ziem. Na podstawie badań terenowych i wyników analiz należy stwierdzić, że gleby te wykazują wiele cech wspólnych z glebami czarnoziemnymi Płaskowyżu Głubczyckiego. Potwierdza to analiza ilościowa składu frakcyjnego związków próchnicznych, jak również przeprowadzone analizy fizykochemiczne kwasów huminowych.
This publication describes physico-hemical properties and the qualitative and quantitative composition of humus from Phaeozems in the Kłodzko district. Physiographic conditions of the area seemed to exclude a possibility of bog-forming processes which determine the black earth development. Based on performed studies one may conclude that the studied soils showed many features common with the soils of the Głubczycki Plateau. Quantitative analysis of fractional composition of humic compounds and physico-chemical properties of humic acids confirmed this conclusion.
Content available remote The IR photoinduced changes in the Y-Ba-Cu-O thin films
The Y-Ba-Cu-O thin films are promising materials because they have not only superconducting properties but also good optical properties, particularly in the IR spectral range. We investigate the photoinduced optical changes in the IR region for oriented Y-Ba-Cu-O thin films deposited on [left angle bracket]110[right angle bracket] surface of ZnSe single crystals, using differential IR spectroscopy Fourier technique in the spectral region between 100 cm/sup -1/ and 450 cm/sup -1/. We have also found the photoinduced photodarkening effect under the influence of the CO/sub 2/ pulse laser ( lambda =10.6 mu m). The possibility of using the above-mentioned materials as promising materials for IR optoelectronics and nonlinear optics is discussed.
Content available remote Rare earth oxide films: their preparation and characterization
Summarises the results of our investigations dealing with preparation of rare earth oxide films and examinations of their physical properties. Different deposition methods have been applied for fabrication of these films and rare-earth-oxide-based thin film coatings. The main results concerning film microstructure and optical properties in the wavelength range from the UV up to the IR are presented. Electrical and dielectric studies have been carried out in the time domain and in the frequency domain (from very low frequencies up to radio frequencies) for selected rare earth oxides. MIM sandwich-type structures have been fabricated for this aim. Trapping levels in these oxides have been investigated. The complex impedance diagnostics was applied to the analysis of the volume of the R/sub 2/O/sub 3/ film and interfacial properties (metal/insulator barriers) of M/R/sub 2/O/sub 3//M thin film structures.
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