A Relative Filtration Index and Fibers of Normal Primes in Extensions of Finite Type

For an extension R A of commutative Noetherian rings the behavior of the associated morphism of topological spaces Spec A Spec R is often measured by its behavior on each of its fibers. Specifically, one studies the 'splitting' (or 'branching') and the 'ramification' that occurs in each fiber. In the classical constructions of faithfully flat analytic extensions (e.g., completion or Henselization) of excellent local rings the splitting and ramification properties are fairly well understood; see EGA IV [6, 18.10], Nagata [13, Sect. 37] or Raynaud [15, Ch. IX]. The strongest results are usually achieved for fibers over a 'normal point' of Spec R, that is, over p Spec R such that R/p is a normal domain [e.g., the property of a normal prime p in a local ring to be 'unibranched', i.e., the Henselization of R/p is a (normal) domain].     

X-ray structure and thermal analysis of a 1∶1 complex between sulfathiazole andβ-cyclodextrin

An inclusion complex with the formula (-cyclodextrin) (sulfathiazole) 8.3 H₂O has been crystallized and characterized by physicochemical methods including single crystal X-ray analysis. The complex crystallizes in the monoclinic system, space group P2₁, witha=15.264(4),b= 16.500(6),c=15.559(5) Å,=117.29(3)^o andZ=2. The structure was solved using published co-ordinates for-cyclodextrin in an isomorphous complex. Refinement by block-diagonal leastsquares yieldedR=0.061 for 4706 unique observed reflections. Inclusion of sulfathiazole produces a slight ellipticity in the host conformation, but the guest adopts a conformation similar to that observed in its polymorphs. The guest is held in the macrocyclic cavity predominantly by hydrophobic forces, with the phenyl ring near the host primary hydroxyl side and the thiazole ring near the secondary hydroxyl side. The complex packs in layers parallel to theac-plane. Layers are linked by hydrogen bonding to water molecules which are located outside the cyclodextrin cavity. An extensive network of hydrogen bonds mediated chiefly by water molecules stabilizes the crystal structure.     

Studies on transition-metal nitrido and oxo complexes. Part VII(1). Substituted nitrido complexes of osmium and ruthenium

Summary Addition reactions of [MNCl₄]^– (M = Os or Ru) with ligands L or L to give [MNCl₄ · L]^– or [(MNCl₄)₂L]^2– (L = pyridine, pyridine-N-oxide,iso-quinoline or DMSO; L = hexamethylenetetramine, pyrazine or dioxan) are described. With NCO^–, [OsNCl₅]^– gives [OsN(NCO)₅]^2– but NCS^– gives a thionitrosyl complex, [Os(NS)(NCS)₅]^2–. Reactions of OsNCl₃(AsPh₃)₂ with pyridine, 1,10-phenanthroline and tertiary phosphites and phosphinites have been studied, as have reactions of triphenylphosphine with OsOCl₄ andtrans- [MO₂Cl₄]^2– (M = Os or Ru). The nitrido-iodo complexes [OsNI₄]^– and OsNI₃, (SbPh₃)₂ are also reported.     

A simple positron lifetime system suitable for low density gases

A conventional positron lifetime system is described which gives data of high statistical accuracy and is especially suitable for gases at low density. Several factors contribute to the significant improvement in performance. The fraction of positrons annihilating in the gas is greatly enhanced by backscattering, and the small dimensions of the pressure vessel coupled with large plastic scintillators yields about 1200 coincidence events per second. Simple electronics are used with no side channel gating, and very clean spectra are obtained with overall resolution better than 1.5 nsec. The true start and stop pulses are counted, which enables the data to be treated by the authors' signal restoration method. The results of measurements in Ar?CO mixtures and data for H₂ and D₂ are presented and discussed.     

The determination of the Lorenz number at high temperatures

In a conducting system consisting of a short fine wire carrying a current between two larges masses of the same metal, the maximum temperature attained depends only upon the properties of the material and the applied potential difference, provided the heat lost from the surface of the wire is negligible compared with that conducted. Measurement of the maximum temperature as a function of the potential difference allows the ratio of the thermal conductivityλ to the electrical conductivityχ, and hence the Lorenz numberλ/χ T whereT is the absolute temperature, to be determined over a wide range of temperature. Experiments with platinum in various gases at atmospheric pressure and also at low gas pressures to test the effect of heat losses due to the surrounding gas are described. Under the conditions of the experiments, these losses are very small except in the case of hydrogen, the results agreeing among themselves and with those previously published. Values of the Lorenz number for palladium from 1000 to 1550? C are given.