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121.
以Mossbauer谱为手段,研究了用于F-T合成的Fe/Zn催化剂的物相结构,并考察了组成及制备方法的影响,同时还对其还原、碳化行为进行了探讨.发现锌对铁的还原有抑制作用,它能够稳定二价铁不被进一步还原.研究还表明,我们所研制的Fe/Zn催化剂是一种高分散度的铁锌化合物,室温下具有超顺磁特性. 相似文献
122.
A. Hazra K. Alexander D. Dollimore A. Riga 《Journal of Thermal Analysis and Calorimetry》2004,75(1):317-330
The present study was aimed at determining the kinetics of evaporation and establishing vapor pressure curves for both single and multi-component systems by thermogravimetry (TG) and differential scanning calorimetry (DSC). Essential oils (e.g. lavender oil, orange oil, clove oil and eucalyptus oil, etc.) are typically multi-component systems consisting of various volatile pure components (e.g. linalyl acetate, limonene, cinnamaldehyde, etc.) which resemble single component systems. In this study linalyl acetate was taken as the calibration compound for TG. The vapor pressure curves for the pure substances were plotted using TG and vapor pressure plots for clove oil and eucalyptus oil were constructed using DSC. The thermodynamic and kinetic parameters of the pure compounds were compared to that of the multi-component systems to quantitatively and qualitatively measure the influence of different compounds on each other. The k-value from the vapor pressure data for linalyl acetate was calculated as 112006 Pa kg0.5mol0.5s-1 m-2 K-0.5. The vapor pressure values were used to determine the Antoine constants using the SPSS 10.0 software.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
123.
124.
Ziya Kantarci Celal Batyak Ergün Kasap 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(1-2):103-108
Infrared spectra of Mn(NH3)2Zn(CN)4.2C6H6 andMn(ethylenediamine)Zn(CN)4.2C6H6 are reported. The spectral data suggest that these compounds are similar in structure toHofmann-Td-type and the en-Td-type clathrates,respectively. There is good evidence for H-bonding from ammoniaN–H to benzene as a to H-bond. 相似文献
125.
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 相似文献
126.
E. A. Zheligovskaya 《Journal of Structural Chemistry》2003,44(5):827-835
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. 相似文献
127.
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).
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.相似文献
128.
V. K. Turchaninov N. N. Chipanina T. N. Aksamentova M. S. Sorokin V. A. Pestunovich 《Russian Chemical Bulletin》1998,47(2):231-236
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. 相似文献
129.
FT-IR and Raman spectroscopic study of hydrated rubidium (cesium) borates and alkali double borates 总被引:1,自引:0,他引:1
Zhu Lixia Yue Tao Wang Jiang Gao Shiyang 《Russian Journal of Inorganic Chemistry》2007,52(11):1786-1792
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. 相似文献
130.