Electrochemical Study of Dialcarb “Distillable” Room‐Temperature Ionic Liquids

Electrode‐dependent potential windows (see picture, GC=glassy carbon) are determined for five dialkylammonium carbamate (dialcarb) room‐temperature ionic liquids in a systematic study of their physical and electrochemical properties. The viscosity and conductivity of the dialcarb ionic liquids, which are “distillable” at low temperature, are comparable to those of some conventional room‐temperature ionic liquids.

     

Broadband dielectric response of the ionic liquid N-methyl-N-ethylpyrrolidinium dicyanamide

Dielectric relaxation measurements as a function of temperature, and of concentration in a non-coordinating solvent, the first reported for an ionic liquid, indicate a crossover in the relaxation mechanism due to varying levels of ion aggregation and the interplay of formation kinetics and relaxation dynamics of associates.     

Muonium dynamics in doped Si above room temperature studied by longitudinal field — μSR

We report longitudinal fieldSR 1/T ₁ measurements in Si from room temperature to 850 K. The data in pure Si and SiB (p-type) can be explained in a two-state model where muonium cycles between its positive and neutral charge states. Within this model, the average muon-electron hyperfine parameter in the neutral state is consistent with muonium at the tetrahedral interstitial site, indicating that at the highest temperatures measured, neutral muonium spends a significant amount of time away from the bond centered site, the calculated potential minimum. Although this is also true for SiP (n-type) at high temperatures, the data in the region between 300–450 K indicates that at least one other state is involved in the dynamics.This work is partially supported by the Natural Sciences and Engineering Research Council of Canada, the Welch Foundation (C-1048 [TLE], D-1053 [RLL] and the U.S. National Science Foundation (DMR-8917639 [TLE,BH]).     

The application of homotopy analysis method to solve nonlinear differential equation governing Jeffery–Hamel flow

In this paper Jeffery–Hamel flow has been studied and its nonlinear ordinary differential equation has been solved through homotopy analysis method (HAM). The obtained solution in comparison with the numerical ones represents a remarkable accuracy. The results also indicate that HAM can provide us with a convenient way to control and adjust the convergence region.     

Low temperature spin dynamics of the geometrically frustrated antiferromagnetic garnet Gd3Ga5O12

The low temperature spin dynamics of the geometrically frustrated antiferromagnet Gd 3Ga 5O (12) (GGG) have been investigated using muon spin relaxation. No evidence for static order is seen down to a temperature of 25 mK or a few percent of the Curie-Weiss temperature. Instead there is a linear decrease in the Gd spin fluctuation rate below 1 K which extrapolates to a small but finite value of 2 GHz at zero temperature. In terms of the spin fluctuations the system appears essentially to remain dynamic at low temperatures (T>0.02 K) and magnetic fields up to 1.8 T.     

Generalizations of σ-models and CpN models,and instantons

Generalized σ-models, called U(N,r) σ-models, are constructed. Fields are determined which allow simple discussion of their instanton solutions and symmetry properties, generalizing known results for Cp^N or SU(N,1) σ-models.