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991.
Antonio Coniglio 《Physica A》1993,200(1-4):165-170
Recent work showing evidence for multiscaling in large two dimensional DLA clusters is reviewed. A connection between multiscaling and multifractality is also shown resulting in a weak localization of the growth sites (δ-sites) in shells around the cluster seed. 相似文献
992.
A convenient route to the daunomycinone precursor 18via a succession of Diels-Alder reactions from 2,7-dichloronaphthazarin (9) is described. In a similar manner, starting from 2,6-dichloronaphthazarin (19) compound 20, a regioisomer of 18,is synthesized. This methodology constitutes a regiospecific approach to (±)-daunomycinone and related anthracyclinones. 相似文献
993.
Alberto Castellón Serrano Antonio Fernández López Amable García Martín Cándido Martín González 《manuscripta mathematica》1996,90(1):479-487
In this paper, we use the known classification of the finite capacity simple alternative pairs and the version of the Litoff
Theorem for Jordan pairs to describe all the strongly prime alternative pairs with nonzero socle. We study the inheritance
of some properties (primeness, nondegenerancy,…) when passing from the original alternative pair to the symmetrized pair.
Thus, we can apply Jordan theoretical results to the alternative case.
This work has been partially supported by 1) the “Plan Andaluz de Investigación y Desarrollo Tecnológico” with project no.
1027 and 2) the DGICYT with project no. PB93-0990 相似文献
994.
Antonio Pasini 《Geometriae Dedicata》1996,60(3):225-236
It is well known that a geometry belonging to a disconnected diagram is the direct sum of geometries corresponding to the connected components of the diagram. On the other hand, chamber systems with a disconnected diagram exist which do not split as direct products of components of smaller rank. Many finite examples of this kind are discussed in Groups of Lie Type and their Geometries (CUP, 1995, pp. 185–214), but none of them is simply connected. In this article, we construct a simply connected finite example. 相似文献
995.
Javier Gamboa Félix Javier Jiménez-Jiménez Alberto Nieto Ignacio Cobeta Alberto Vegas Miguel Ortí-Pareja Teresa Gasalla José Antonio Molina Esteban García-Albea 《Journal of voice》1998,12(4):444-452
To quantify several acoustic features of the voice in patients with essentialtremor (ET), 28 patients and 28 age- and sex-matched controls were studied. ET severity was assessed with the rating scale for tremor of Fahn, Tolosa, and Marín. The Computerized Speech Lab 4300 program (Kay Elemetrics) was used. Two-second samples of a sustained /a/ and a sentence were captured with a microphone and laryngograph equipment. Measures included fundamental frequency (F0), frequency perturbation (fitter, Koike algorithm), intensity perturbation (shimmer, Horii algorithm), and harmonic-to-noise ratio (H/N, Yumoto algorithm) of the vowel /a/, and the frequency and intensity variability of the sentence, phonational range, and dynamic range at the natural frequency, maximum phonational time, and s/z ratio. All subjects underwent indirect laryngoscopy and/or laryngeal fibroscopy. When compared with controls, ET patients showed higher jitter, lower H/N ratio (the last one only with laryngographic signal), of the vowel /a/, lower frequency variability in the microphonc signal, lower intensity variability in the laryngographic signal of the sentence, and significantly lower dynamic range at natural frequency of phonation. ET patients reported higher frequency of the presence of high voice intensity, tremor, and struggle. Several acoustic parameters were influenced by the severity of the disease, including shimmer, jitter, H/N ratio, frequency variability of the sentence, and s/z ratio, although neither of the acoustic analysis values or the phonetometric measurements were affected by the presence of voice tremor or by a successful pharmacological treatment of ET. 相似文献
996.
Antonio Raudino Franco Battaglia 《Journal of Electron Spectroscopy and Related Phenomena》1980,20(3):327-331
The He(II) spectra of the unsubstituted metallocenes {M(η-C5H5)2}, M V, Cr, Mn, Fe, Co, Ni and Ru, and of {Mn(η-C5H4Me)2} are reported; both He(I) and He(II) spectra of some decamethylmetallocenes {M(η-C5Me5)2}, where M Mg, V, Cr, Mn, Fe, Co and Ni, are also given. Intensity changes between the He(I) and He(II) spectra are shown to provide a reliable guide to band assignment. A ligand field treatment of the decamethylmanganocene cation, including limited configuration interaction, gives values for Δ2, B and C; these values are also in good agreement with the photoelectron spectra of {M(η-C5Me5)2} where M V, Cr and Fe. Overlap between the ligand and metal “d” band structures prevents complete assignment in the cases of Co and Ni. 相似文献
997.
María Del Carmen Chacn María Del Carmen Pardot Jos Luis Soto Antonio Lorente Luis Fuentes 《Journal of heterocyclic chemistry》1982,19(2):421-423
Reaction of cinnamonitriles with malononitrile, in methanolmethoxide, yield dihydropyridines, which by aromatisation give pyridines. Pyridine is directly obtained when p-nitrocinnamonitrile is used 相似文献
998.
999.
Pier Luigi Luisi Francis J. Bonner Antonio Pellegrini Peter Wiget Romain Wolf 《Helvetica chimica acta》1979,62(3):740-753
The quaternary ammonium salt methyl-trioctylammonium chloride enables the transfer of α-chymotrypsin, trypsin, pepsin and glucagone from water to cyclohexane. Reversed micelles, whose polar core solubilizes both protein and water, are probably formed in the apolar phase. The influence of various parameters on the phase transfer (concentration, pH, solvent, temperature, etc.) has been investigated. Absorption, fluorescence and circular dichroism studies of the biopolymers in the cyclohexane system have been carried out. For trypsin and chymotrypsin, the CD. signal in the 200 nm region is very similar in water and in cyclohexane, which suggests that the polypeptide folding is not substantially different in the two phases. The fluorescence quantum yield is always much larger in the cyclohexane phase than in water. The longer wavelength region of the UV. absorption spectrum is slightly red-shifted relative to water, and a band at 225 nm, probably arising from the aromatic chromophore, is apparent in the organic phase. Reasons for these spectral perturbations are discussed. The enzymes transferred from water into cyclohexane phases can be continuously retransferred into a second water phase. The possible relevance of this ‘double transfer’ as a model for the vectorial transport of biopolymers or a separation technique is discussed. 相似文献
1000.