Polymeric imidazolium ionic liquids as valuable stationary phases in gas chromatography: Chemical synthesis and full characterization

Seven new functionalized polymerizable ionic liquids were chemically prepared, and later applied for the preparation of polymeric stationary phases in gas chromatography. These coated GC columns, which exhibited good thermal stabilities (240–300 °C) and very high efficiencies (3120–4200 plates/m), have been characterized using the Abraham solvation parameter model. The chromatographic behavior of these polymeric IL columns has been deeply studied observing excellent selectivities in the separation of many organic substances such as alkanes, ketones, alcohols, amines or esters in mixtures of polar and non polar solvents or fragrances. Remarkably, the challenging separation of xylene isomers has been possible using a bis(trifluoromethylsulfonyl)amide based imidazolium IL coated column as a gas chromatography stationary phase.     

Measurement of the neutron F2 structure function via spectator tagging with CLAS

We report on the first measurement of the F(2) structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ?100 MeV/c and their angles to ?100° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F(2)(n) data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65相似文献   

Erratum to “On a Classical Theorem on the Diameter and Minimum Degree of a Graph”

The original version of the article was published in[1]. Unfortunately, the original version of this article contains a mistake:in Theorem 6.2 appears that β(n, Δ)=(n-Δ+5)/4 but the correct statement is β(n, Δ)=(n-Δ+4)/4. In this erratum we correct the theorem and give the correct proof.     

Explicit solutions for one-dimensional two-phase free boundary problems with either shrinkage or expansion

We consider a one-dimensional solidification of a pure substance which is initially in liquid state in a bounded interval $[0,l]$. Initially, the liquid is above the freezing temperature, and cooling is applied at $x=0$ while the other end $x=l$ is kept adiabatic. At the time $t=0$, the temperature of the liquid at $x=0$ comes down to the freezing point and solidification begins, where $x=s\left(t\right)$ is the position of the solid–liquid interface. As the liquid solidifies, it shrinks ($0<r<1$) or expands ($r<0$) and appears a region between $x=0$ and $x=rs\left(t\right)$, with $r<1$. Temperature distributions of the solid and liquid phases and the position of the two free boundaries ($x=rs\left(t\right)$ and $x=s\left(t\right)$) in the solidification process are studied. For three different cases, changing the condition on the free boundary $x=rs\left(t\right)$ (temperature boundary condition, heat flux boundary condition and convective boundary condition) an explicit solution is obtained. Moreover, the solution of each problem is given as a function of a parameter which is the unique solution of a transcendental equation and for two of the three cases a condition on the parameter must be verified by data of the problem in order to have an instantaneous phase-change process. In all the cases, the explicit solution is given by a representation of the similarity type.     

Harmonic mappings of Kähler manifolds to locally symmetric spaces

Research partially supported by the National Science Foundation.     

A new upper limit for the decay μ→eee

A search for the decay μ⁺→e⁺e⁺e⁻, in which no candidate was found, yields a new upper limit for the branching ratio R_μ→3e<1.6×10⁻¹⁰ (90% confidence). A total of 16 decays were observed, in agreement both in number and momentum distribution with V - A theory.     

Catalytic activity of aluminium and copper-doped magnetite in the high temperature shift reaction

Aluminium and copper-doped magnetite was evaluated as high temperature shift catalyst and compared with a hematite-based sample. The first one is less active but can save energy in industrial processes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Diels-Alder reaction between indoles and cyclohexadienes photocatalyzed by pi,pi aromatic ketones

[structure: see text] Diels-Alder reactions between indoles and cyclohexadienes can be photocatalyzed by benzoylthiophenes. Both experimental and theoretical studies show that the reactions occur through ternary excited triplet state complexes (triplet triplexes).