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141.
Ferrini V Forte C Geppi M Pizzanelli S Veracini CA 《Solid state nuclear magnetic resonance》2005,27(4):215-222
Wideline 1H FID and relaxation measurements of a relatively simple motionally heterogeneous system, the triblock copolymer styrene–butadiene–styrene, have been performed in a temperature range between the polystyrene and polybutadiene glass transition temperatures. The two FID and the two spin lattice relaxation time in the rotating frame (T1ρ) components found at each temperature have been correlated by means of a two-dimensional approach. It is shown that this approach allows dynamic information, not accessible simply by interpreting proton T1 and T1ρ data, to be revealed. In the case examined, the correlation found could be confirmed by high-resolution 1H T1ρ-selective 13C Cross Polarization experiments. 相似文献
142.
We construct a relativistic quantum field theory in 2 + 1 dimensions whose Fock states provide a multivalued representation of the Poincaré group. We add a topological term to the action of a scalar field theory and we show that this endows the path integral of the theory with an operator-valued cocycle which modifies the transformation properties of physical states. We demonstrate that one-particle states carry (in general) fractional spin. We determine the spin of many-particle states and we prove a generalized spin-statistics relation. We propose an equation of motion for on-shell states which generalizes naturally the Dirac equation. 相似文献
143.
Sommaire On formule et démontre un principe d'équipartition de l'énergie dans la thèorie statistique des milieux continus, considérés
comme milieux possédant une infinité dénombrable de degrés de liberté.
Un tel principe s'accorde avec le principe classique d'é1uipartition de l'énergie, relatif aux milieux à un nombre fini de degrés de liberté, et il en est une extension naturelle.
Travaux exécutés pour la réalisation du programme du Groupe de recherche no 7 du C. N. R. (1962–1963).
Le principe de l'équipartition de l'énergie, traité dans le § 3 a été établi parB. Forte. Les liaisons entre ce principe et le principe classique ont été developpées par M.lleBraccini, auteur aussi de l'introduction de cet ouvrage. 相似文献
144.
The equilibrium I2(g) + 2NO(g) = 2INO(g) has been studied at room temperature by ultraviolet absorption spectroscopy. The equilibrium constant has been measured as Kp = (2.7 ± 0.3) × 10?6 atm?1 at 298 K. Third-law calculations lead to ΔH°f,298 (INO) = 120.0 ± 0.3 kJ/mol. The relative absorption spectrum of INO has been measured between 225 and 300 nm. Quantitative measurements gave ?(λmax = 238 nm) = (1.79 ± 0.5) × 104 L/mol·cm and ?(410 nm) = 234.7 ± 21 L/mol·cm. 相似文献
145.
The basic intention of this note is to characterize a global condition as the starshapedness of a set S by means of the existence of points of maximal visibility in S, that is a local property. 相似文献
146.
Bocca B Lamazza A Pino A De Masi E Iacomino M Mattei D Rahimi S Fiori E Schillaci A Alimonti A Forte G 《Rapid communications in mass spectrometry : RCM》2007,21(11):1776-1782
An analytical procedure applicable to restricted sample sizes was developed and applied to the analysis of 30 chemical elements in colorectal biopsies of healthy patients. Acidic microwave digestion processed =10 mg of tissue at 80 degrees C in 15-mL polystyrene liners. The digests were diluted to a volume of 2 mL with high-purity water and directly analyzed by sector field inductively coupled plasma mass spectrometry without further specimen handling. A careful selection of isotopes and instrumental resolution permitted the quantification in a single analytical sequence both of the elements present at parts per trillion and of those at parts per million. The accuracy calculated on BCR 184 ranged from 93.3-110%, the recoveries of the biopsy material was in the range 95.2-105%, the precision was <10%, and the blank levels were much below those expected in biopsy samples. The metal concentrations (on a dry-weight basis) in colorectal normal tissue showed a large range of variation: Ag, Au, Be, Bi, Co, Li, Sb, Tl, V, W and Zr were below 50 ng g(-1); As, Ba, Cd, Cr, Cs, Hg, Mo, Ni, Pb, Se and Sn were distributed from 100 to 500 ng g(-1); Al, Cu, Fe, Mn, Sr and Zn were from a few microg g(-1) to 100 microg g(-1); and Ca and Mg were at a level of 1000 microg g(-1). These data represent the first attempt to achieve an elemental profile in the colorectal mucosa of healthy patients as baseline level measurements for studies focused on the imbalance of chemical elements in diseased mucosa. 相似文献
147.
Cliciane Guadalupe de Jesus Cristiane Maria Sampaio Forte Karen Wohnrath Christiana Andrade Pessôa Janete Elisa de Sá Soares Sérgio Toshio Fujiwara Pedro de Lima‐Neto Adriana Nunes Correia 《Electroanalysis》2011,23(8):1814-1820
A (SiPy+Cl?/CuTsPc)5 layer‐by‐layer film was employed for the electroanalytical determination of promethazine hydrochloride in BR buffer pH 5.0 with peaks at 0.48 and 0.79 V. After optimisation of the square‐wave parameters (f=100 s?1, a=40 mV and ΔEs=2 mV), the peak at 0.79 V was used for quantification and a detection limit of 8.71×10?9 mol L?1 and a quantification limit of 9.31×10?8 were calculated. The applicability of this procedure was tested on commercial formulations of promethazine hydrochloride by observing the stability, specificity, recovery and precision of the procedure in complex samples, without any preliminary treatment. 相似文献
148.
149.
A hydrofluoric acid (HF)-treated soil sample was studied by 13C NMR spectroscopy. Cross polarization (CP) Magic Angle Spinning (MAS) 13C spectral editing and relative CP peak quantitation, obtained through variable-contact-time experiments, were used to aid the interpretation of the spectrum. The combination of these two types of experiment allowed to obtain a higher degree of detail on the composition of the sample with respect to a standard CP MAS experiment. 相似文献