Freeze-out conditions in ultrarelativistic heavy-ion collisions

We present recent results on single particle transverse momentum distributions of pions, kaons and protons, measured in CERN Experiment NA44, of 200 AGeV/c S+S and 158 AGeV/c Pb+Pb central collisions. By comparing these data with thermal and transport models, freeze-out parameters like the temperatureT _fo and the chemical potentials (μ _q ,μ _s ) are extracted and discussed.     

MartingaleBMO spaces with continuous time

ВВОДьтсь ДВА НОВых кл АссА пРОстРАНстВBMO, ИМ ЕУЩИх БОльшОЕ жНАЧЕНИЕ В тЕОРИИ ИНтЕРпОлИРО ВАНИь, И ДОкАжыВАУтсь НЕкОтОРыЕ сООтНОшЕНИь ЁкВИВАл ЕНтНОстИ Их И ОБыЧНых пРОстРАН стВBMO. ИжУЧАУтсь сООтВЕтстВУУЩИЕ “sharp”Ф УНкцИИ И ОБОБЩАУтсь НЕкОтОР ыЕ тЕОРЕМы гАРсИИ, И ФЕ ФФЕРМАНА И стЕИНА.     

Synthesis of single- and multi-wall carbon nanotubes over supported catalysts

The quantities of deposited carbon were measured and the quality of the nanotubes was characterized by means of transmission electron microscopy and scanning tunneling microscopy. The inner and outer diameters of the nanotubes were also measured and the diameter distribution histograms were established. The multi-wall straight and coiled nanotubes were found to be quite regular with an average inner (outer) diameter of 4–7 nm (15–25 nm) and with lengths up to 50 μm. The walls contain concentric cylindrical graphene sheets separated by the graphitic interlayer distance. The single-wall nanotubes were found as bundles of hundreds of aligned straight 1-nm-diameter nanotubes with lengths up to 1-μm. The influence of various parameters such as the method of catalyst preparation, the nature and the pore size of the support, the nature of the metal, the quantity of catalyst active particles, and the reaction conditions on the nanotubes formation were studied. The numbers and dimensions of the catalyst active particles dispersed on the support were found to be of importance in regulating the shape of the produced nanotubes. Following these results, a model of growth mechanism was suggested for the nanotubes obtained by this method. Received: 5 January 1998     

Bridged Ferrocenes VIII. Correlation of redox potentials with structure

The redox potentials for oxidation of ferrocenes with hydrocarbon bridges and of corresponding ketoferrocenes were measured. For the reduced compound correlations were observed between the potentials and the iron to ring distances. For the ketoferrocenes, the importance of proper alignment of the carbonyl with the cyclopentadienyl rings is noted. Other possible relationships are discussed.     

Adsorption von fl:ussigen Gemischen an Bentonit und organophilen Bentonit

Ohne Zusammenfassung     

A study of transverse and longitudinal momentum correlations in proton diffraction dissociation at 14 GeV/c

We present data on momentum correlations both in and out of the production plane for the reactions π⁺p→π_f⁺(π⁺n) and π^?p→π_f^?(π^?Δ⁺⁺). The dissociation products show strikingly similar transverse momentum distributions which in terms of exchange models suggest an equal amount of pion and baryon exchange. For both reactions, we find an approximate factorization in the projectile frame between the transverse momentum of π_f and the longitudinal momenta of the dissociation products. Exchange models predict this result equally in both reactions, but it appears much more clearly in the Δ reaction. Finally, we relate the observed longitudinal and transverse momentum distributions in a way suggested by an isotropic decay model.     

Experimental results on diffractive one-pion production at the CERN ISR

New experimental results are reported on diffractive dissociation of protons into (nπ⁺) in proton-proton collisions at a centre-of-mass energy of $\text{s}\text{= 45}\text{GeV}$. The data were obtained using the Split-Field-Magnet detector at the CERN Intersecting Storage Rings. We have searched for resonance contributions and found peaks at mass values of 1.5 GeV, 1.65 GeV, and 2.1 GeV. A dip in $\text{d}\text{σ}\text{d}\text{t}$ is observed at low t and low mass; it is most pronounced for events with neutrons emitted at 90° in the Gottfried-Jackson frame. The correlation between mass and slope depends strongly on θ_J. The cross section of the channel pp → pnπ⁺ is 400 ± 110 μb at $\text{s}\text{= 45}\text{GeV}$, giving an energy dependence of s^?0.30±0.07 for isospin exchange zero in this channel.     

Herstellung einiger verzweigter Paraffine im oligomeren Bereich

Synthesis of some branched paraffins of high molecular weight Synthesis and properties of two series of branched paraffins of high molecular weight are described. In the course of the preparation of one of the starting materials the Wolff-Kishner reduction of a sterically hindered ketone, unstable in basic medium, has been elaborated.     

Investigations in the field of radiation-induced solid state polymerization-XXXI

Binary systems of N-vinyl succinimide and endomethylene tetrahydrophtalic acid monoallyl ester with some additives were studied. It was established that the amount and nature of the quasi-eutectic structure could be regulated to the desired extent only when crystallization was performed under nearly isothermal conditions. In the present conditions for heat transfer, one component of the binary system should have a maximum linear crystallization rate low enough to produce a maximum linear crystallization rate of the quasi-eutectic structure less than 1 × 10^?2 mm/sec. In many cases, kinetic results could definitely be connected with qualitative and quantitative changes in the quasi-eutectic structure. Some phenomena suggested the roles of certain structural features and the phase conditions of the ternary system formed by the polymer produced.     

Experience with mixed-salt ion-selective sulphate electrodes

Sulphate ion-selective electrodes with mixed-salt, pressed-pellet membranes have been manufactured and tested for response, stability and selectivity. Acceptable performance was obtained only with selected specimens. The addition of small amounts of cuprous sulphide to the membrane had no significant effect.