Electron scattering in CdxHg1−xTe

Experimental studies of the electron mobility in Cdinx,Hgin1?xTe/0x/0.33, 10¹⁵ cm^?3n10¹⁸ cm^?3, 4.2 K ?T ?300 K/and of the thermoelectric power of intrinsic HgTe from 300 K down to 5 K are reported. These results are interpreted in terms of calculations based on the variational solution of the Boltzmann equation. Analysis shows that in pure samples at low temperatures, the electron mobility is limited by ionized donors, heavy holes, and, in some cases, unresolved defect scattering. In the doped samples with x0̆.1, disorder scattering also becomes significant. Polar-optical phonon scattering is dominant at high temperatures. The sharp decrease of mobility in the region 20–40 K, which occurs for pure samples with x0̌.14, is explained by interband optical phonon scattering. The thermoelectric power of intrinsic HgTe is strongly affected by phonon-drag of holes at low temperatures and by electron-electron scattering at high temperatures.     

Onset of deconfinement and critical point: NA49 and NA61/SHINE at the CERN SPS

This paper is dedicated to the memory of József Zimányi one of the founders of the experiment NA49 at the CERN SPS. Firstly, the paper summarizes the main results of NA49 concerning observation of the onset of deconfinement in central Pb+Pb collisions at the low SPS energies. Secondly, it sketches the physics program of NA61 at the CERN SPS, the successor of NA49, which in particular aims to discover the critical point of strongly interacting matter. Finaly, a brief review of the future experimental programs in the CERN SPS energy range is given.     

A Parametric Family of Quintic Thue Equations II

 In this paper we completely solve the family of Thue equations

Minima, pentes et algèbre tensorielle

Slopes of an adelic vector bundle exhibit a behaviour akin to successive minima. Comparisons between the two amount to a Siegel lemma. Here we use Zhang’s version for absolute minima over the algebraic numbers. We prove a Minkowski-Hlawka theorem in this context. We also study the tensor product of two hermitian bundles bounding both its absolute minimum and maximal slope, thus improving an estimate of Chen. We further include similar inequalities for exterior and symmetric powers, in terms of some lcm of multinomial coefficients.     

Quasi-commuting extensions of groups

We prove that every monoid obtained from a group by adding new generators submitted to relations of a certain simple type embeds in a group of fractions. This applies in particular to the singular braid monoid.     

Simul 6: A fast dynamic simulator of electromigration

Simul 6 is a 1D dynamic simulator of electromigration based on the mathematical model of electromigration in free solutions. The model consists of continuity equations for the movement of electrolytes in a separation channel, acid–base equilibria of weak electrolytes, and the electroneutrality condition. It accounts for any number of multivalent electrolytes or ampholytes and provides a complete picture about dynamics of electromigration and diffusion in the separation channel. The equations are solved numerically using software means which allow for parallelization and multithreaded computation. Simul 6 has a user-friendly graphical interface. It is typically used for inspection of system peaks (zones) in electrophoresis, stacking and preconcentrating analytes, optimization of separation conditions, method development in either capillary zone electrophoresis, isotachophoresis, and isoelectric focusing. Simul 6 is the successor of Simul 5, and has been launched as a free software available for download at https://simul6.app/ .     

Efficient synthesis of tricyclic benzobisoxazines by silica gel catalysis

A new method for the synthesis of tricyclic benzobisoxazines, based upon silica gel-catalyzed formation of two 3,1-oxazine rings, is reported. The reversibility of the condensation reaction, forming an oxazine ring, allows for implementation of silica gel catalyzed ketone exchange in benzobisoxazine, thus enabling access to nonsymmetric derivatives of benzobisoxazines.     

Chemical kinetic study of the effect of a biofuel additive on jet-A1 combustion

The kinetics of oxidation of kerosene Jet A-1 and a kerosene/rapeseed oil methyl ester (RME) mixture (80/20, mol/mol) (biokerosene) was studied experimentally in a jet-stirred reactor at 10 atm and constant residence time, over the temperature range 740-1200 K, and for variable equivalence ratios (0.5-1.5). Concentration profiles of the reactants, stable intermediates, and final products were obtained by probe sampling followed by on-line and off-line gas chromatography analyses. The oxidation of these fuels in these conditions was modeled using a detailed kinetic reaction mechanism consisting of 2027 reversible reactions and 263 species. The surrogate biokerosene model fuel used here consisted of a mixture of n-hexadecane, n-propylcyclohexane, n-propylbenzene, and n-decane, where the long-chain methyl ester fraction was simply represented by n-hexadecane. The proposed kinetic reaction mechanism used in the modeling yielded a good representation of the kinetics of oxidation of kerosene and biokerosene under jet-stirred reactor conditions and of kerosene in a premixed flame. The data and the model showed the biokerosene (Jet A-1/RME mixture) has a slightly higher reactivity than Jet A-1, whereas no major modification of the product distribution was observed besides the formation of small unsaturated methyl esters produced from RME's oxidation. The model predicts no difference in the ignition delays of kerosene and biokerosene. Using the proposed kinetic scheme, the formation of potential soot precursors was studied with particular attention.