论法国行政法的基本特征

法国是大陆法系的典型国家,其行政法在法律机构、法律体系、法律渊源、法律观念等诸多方面具有鲜明的特征,这些特征的形成有着深厚的思想基础与深刻的社会历史原因。     

Reactivite de carbanions β cetophosphorothiolate: Réarrangement phosphorothiolate-phosphate d'énol

The stabilization of S-alkanoate O,O-dialkyl phosphates carbanions has been tried. A enol phosphate-phosphorothiolate rearrangement is observed and the mechanism is described. This new transposition has been applied to the synthesis on various enol phosphates with thioether of enol function of phytosanitaire interest.     

Synthese de la cyclo-5'-8 desoxy-5' adenosine: stereochimie et mecanisme de la cyclisation d'un derive de l'iodo-5' adenosine par le zinc

N,N'-Dibenzoyl 2', 3'-O-isopropylidene 5'-deoxy 5'-iodo adenosine can efficiently transformed into the corresponding 5',8-cyclo-7,8-dihydronucleoside by zinc in pyridine. Only one diastereoisomer is obtained. By spin decoupling and NOE techniques at 250 MHz, the R-configuration at C-8 was established. This compound showed typical dihedral angles of about 90° for the vicinal protons H-1', H-2' and H-3', H-4'. Using adenosine derivatives stereospecifically labelled at C-5', it was demonstrated that the cyclisation occurs with racemisation at that position.     

Kinetics and mechanistic aspects of the reduction of chromium dioxide

Thermogravimetric experiments on very small, single-crystalline, acicular particles of CrO₂, of homogeneous size and shape, indicate that the reduction of CrO₂ by hydrogen to produce CrOOH, can be explained by means of a unidimensional diffusion mechanism. Hydrogen diffuses along the empty tunnels that exist parallel to the c axis in the rutile-like unit cell. The corresponding diffusion equation is D = 10^?6(?19.3 ± 2.3)/RT cm²/sec, and is valid for 490 < T < 519 K and 30 < P_H2 < 110 Torr.     

法国西北部古生代地层及相

简要介绍了法国西北部波罗乃和布勒塔尼两地区的古生界。以泥盆系为重点,列举了4个重要剖面,就地层划分、重要化石的分布和沉积相特征作了讨论。     

Electrochemistry in molten NaAlCl4 (at 210°C): Identification of dissolved oxide-containing species,solubility of alumina in terms of pCl− and properties related to H2O in this melt

It has been shown that a nickel electrode is an indicator of the presence of oxide ions dissolved in chloroaluminate melts. From quantitative interpretation of electrochemical results (voltammograms and potentiometric measurements), O^2? has appeared to behave, in terms of the chloro-acidobasicity concept, as a strong dibase, through a solvolytic reaction giving AlOCl₂^? as solvated form. AlOCl₂^? itself is a weak base, according to the system:AlOCl₂^?AlOCl+Cl^?, pK_B/mol kg^1-=4.35 (at210°C) Thus O^2? behaves cumulatively as a tribase. AlOCl is the solvated form of O^?II in very acidic melts.A saturation effect by Al₂O₃ appeared when the concentration of O^?II was increased. The solubility of Al₂O₃ in chloroaluminate melts (one third of total O^?II solubility) was determined from the electrochemical results obtained. A minimum of 0.13% in weight (solubility of O^?II=4×10^?2 mol kg^?1), is observed for pCl^?=4.5 that is in a mixture containing 51.4 moles per cent of AlCl₃. The solubility is increased by adding either more AlCl₃ (formation of AlOCl) or NaCl (formation of AlOCl₂^?). Its variation versus pCl^? has been expressed quantitatively.Through a study of the system HCl/H₂O, it was pointed out that hydrolysis of chloroaluminate melt does not occur to a great extent in basic media. On the contrary, elimination of oxide ions through H₂O formation by reaction with HCl was shown to be possible. A quantitative relation, which binds the total concentration of O^?II, pCl^? and the respective partial pressures of gaseous HCl and H₂O in equilibrium with the melt, is given.A treatment in order to carry out this purification in these melts appears necessary in order to prevent many dissolved metallic ions from precipitating under the form of oxides.     

Intramolecular cyclization of cycloalkene carboxylic acid chlorides

Thermal cyclization of cyclooctene-4-yl-carboxylic acid chloride (5) and cycloheptene-4-yl-carboxylic acid chloride (10) yielded mixtures of mainly endo and exo 2-chlorobicyclo[3.3.1]nonane-9-one (7 and 8), and mixtures of endo and exo 2-chlorobicyclo[3.2.1]octane-8-one (12 and 13), respectively. AlCl₃-catalyzed cyclization of 10 gave the same product composition as the uncatalyzed reaction. In the AlCl₃-catalyzed cyclization of 5 considerable amounts of bicyclo[3.3.1]non-2-en-9-one (6) and exo 3-chlorobicyclo[3.3.1]nonane-9-one (9) were obtained in addition to 7 and 8.     

Limits of structures and the example of tree semi-lattices

The notion of left convergent sequences of graphs introduced by Lovász et al. (in relation with homomorphism densities for fixed patterns and Szemerédi’s regularity lemma) got increasingly studied over the past $10$ years. Recently, Ne?et?il and Ossona de Mendez introduced a general framework for convergence of sequences of structures. In particular, the authors introduced the notion of $QF$-convergence, which is a natural generalization of left-convergence. In this paper, we initiate study of $QF$-convergence for structures with functional symbols by focusing on the particular case of tree semi-lattices. We fully characterize the limit objects and give an application to the study of left convergence of $m$-partite cographs, a generalization of cographs.