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排序方式: 共有1163条查询结果,搜索用时 9 毫秒
1.
N. M. Agababyan M. R. Atayan M. Charlet J. Czyżewski E. A. De Wolf K. Dziunikowska A. M. F. Endler Z. Sh. Garutchava H. R. Gulkanyan R. Sh. Hakobyan J. K. Karamyan D. Kisielewska W. Kittel S. S. Mehrabyan Z. V. Metreveli E. C. Oliveira K. Olkiewicz F. K. Rizatdinova E. K. Shabalina L. N. Smirnova M. D. Tabidze L. A. Tikhonova A. V. Tkabladze A. G. Tomaradze F. Verbeure S. A. Zotkin 《Zeitschrift fur Physik C Particles and Fields》1996,71(1):405-414
The NA22 data onπ ? π ? correlations are analyzed in terms of a number of two- and three-dimensional parametrizations (Gaussian space-time, Goldhaber, Bowler string-like, Bertsch hydrodynamical, Kopylov-Podgoretskii, etc.). Contrary to the results obtained for e+e? andµp collisions, the Goldhaber parametrization, as well as string-like models, fail in describing the hadron-hadron data. Better fits are obtained in the framework of surface-emitting fireball-like models, both when including and excluding hydrodynamical expansion of nuclear matter. Our results indicate that pion radiation occurs at earlier stages of matter evolution than in nuclear collisions. 相似文献
2.
M. T. Czyżyk M. Podgórny A. Balzarotti P. Letardi N. Motta A. Kisiel M. Zimnal-Starnawska 《Zeitschrift für Physik B Condensed Matter》1986,62(2):153-161
Using the new information supplied by extended-x-ray-absorption-fine-structure measurements and the results of our structural model, we compute the bond probability of a few ternary semiconducting III–V and II–VI alloys as a function of temperature and composition in the framework of a modified quasi-chemical approximation. We derive the thermodynamic functions of mixing, considering both elastic and chemical contributions to the bond energies. We examine how the deviation from the full randomness affects the ordering of such alloys and we construct the phase diagrams in the region of phase separation. Possible formation of ordered compounds at low temperatures is predicted. 相似文献
3.
Malonate, succinate and glutarate of yttrium were obtained by dissolving Y(OH)3 in a solution of the corresponding acid and crystallization, whereas adipate, pimelate, suberate, azelate and sebacate in the reaction of YCl3 with the ammonium salt of the acid. Yttrium alkanodicarboxylates were prepared as crystalline solids with general formula Y2O3.nH2O, wheren=3, 4, 6, 7. On the basis of IR spectra the way of coordination COO– - Y3+ was established. Yttrium malonate, succinate, glutarate, azelate and sebacate heated lose crystallization water and next anhydrous complexes are transformed to Y2O3, whereas yttrium adipate, pimelate and suberate on heating lose some water molecules and, the mono- or dihydrates formed are decomposed to Y2O3. The properties of the studied complexes change discretely according to odd or even number of carbon atoms in the chain.
Zusammenfassung Durch Auflösen von Y(OH)3 in einer Lösung der entsprechenden Säure und anschliessendem Kristallisieren wurden Yttriummalonat,-succinat und -glutarat dargestellt, das Yttriumadipat, -pimelat-, -suberat und -azelainat und sebacate hingegen in der Reaktion von YCl3 mit dem Ammoniumsalz der Säure. In Form kristalliner Feststoffe wurden Yttriumalkanodicarboxylate der allgemeinen Formel Y2L3,nH2O mitn=3, 4, 6 bzw. 7 hergestellt. Ausgehend von den IR-Spektren konnte die Art der Koordinierung als COO– y3+ festgestellt werden. Beim Erhitzen geben Ytrriummalonat, -succinat, -glutarat, azelainat und -sebazat ihr Kristallwasser ab, aus den anhydratierten Komplexen bildet sich anschliessend Y2O3, während Yttriumadipet, pimelat und -suberat einige Wassermoleküle verlieren und die monooder dihydratierten Formen sich dann zu Y2O3 zersetzen. Die Eigenschaften der untersuchten Komplexe variieren eindeutig in Abhängigkeit davon, ob sich in der Kette eine gerade oder ungerade Anzahl von Kohlenstoffatomen befindet.相似文献
4.
Exchange interactions in copper(II) complexes with tridentate Schiff bases: EPR and magnetic studies
Bogusława Jeżowska-Trzebiatowska Julia Jezierska Jerzy Baranowski 《Chemical physics letters》1977,52(3):590-594
The influence of the nature of ligands upon the magnetic and EPR properties was investigated for the series of polynuclear Cu(II) complexes with tridentate Schiff bases. A similar tendency of changes in the |J| and D parameters was found for binuclear Cu(II) complexes with ligands derived from condensation of 3-amino-1-propanol with 2-hydroxyaldehydes and acetylacetone as well as for Cu(II) complexes with condensation products of o-aminophenol and β-diketones. The Cu(II) complex with Schiff base of 1-amino-2-propanol and acetylacetone exhibits ferromagnetic behaviour suggesting tetrameric structure. 相似文献
5.
Infrared spectra of K3[ReO2(CN)4] have been recorded using polarized radiation and oriented single crystals. The dichroic behaviour of the bands is analyzed and discussed on the basis of molecular geometry and the oriented molecular model. Experimentally determined dichroic ratios are used to obtain a full set of vibrational frequencies. By combining these data with those obtained from Raman spectra, the fundamental internal and lattice vibrations are assigned. 相似文献
6.
J. Dabrowski J. Rożynek G.S. Anagnostatos 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):125-131
It is shown that among four models of the Nijmegen baryon-baryon interaction only model F --which leads to a repulsive potential
felt by the Σ hyperon inside the nucleus-- is consistent both with the analysis of Σ- atoms and of the (K
-,π) reactions. The Nijmegen models are used to determine the strong complex single-particle (s.p.) potential of Σ-, and to calculate the strong-interaction shifts and widths of the lowest observed levels of Σ- atoms. The results obtained with model F are in best agreement with the experimental data.
Received: 15 January 2002 / Accepted: 14 March 2002 相似文献
7.
Agnieszka Mikolajczuk Elżbieta Perez Przyk Michael Berglund Philip Taylor 《Isotopes in environmental and health studies》2013,49(1):2-12
Compound specific isotopic analysis (CSIA) can provide information about the origin of analysed compounds – in this case, polycyclic aromatic hydrocarbons (PAHs). In the study, PAHs were extracted from three dust samples: winter and summer filter dust and tunnel dust. The measurement was performed using the method validated in our laboratory using pure, solid compounds and EPA 610 reference assortment. CSIA required an appropriate clean-up method to avoid an unresolved complex in the gas chromatographic analysis usually found in the chromatography of PAHs. Extensive sample clean-up for this particular matrix was found to be necessary to obtain good gas chromatography–combustion–isotope ratio mass spectrometry analysis results. The sample purification method included two steps in which the sample is cleaned up and the aliphatic and aromatic hydrocarbons are separated. The concentration of PAHs in the measured samples was low; so a large volume injection technique (100 μl) was applied. The δVPDB 13C was measured with a final uncertainty smaller than 1 ‰. Comparison of the δVPDB 13C signatures of PAHs extracted from different dust samples was feasible with this method and, doing so, significant differences were observed. 相似文献
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10.
A. Huczko H. Lange M. Sioda Z. Rżanek-Boroch M. Morvová 《Czechoslovak Journal of Physics》2000,50(5):615-622
The decomposition of benzene and acetylene in electric carbon arc and non-equilibrium discharge plasmas was studied in order to produce carbon gas. The composition of various gaseous and condensed products (fullerenes, amorphous carbon and graphite, amino acids, aliphatic and aromatic hydrocarbons) were analysed and discussed in relation to the operating parameters. 相似文献