a method is described by which it is possible to determine the high barrier to ring inversion and hindered rotation by neat racemization of optically active compounds when the racemization is caused by ring inversion or hindered rotation. the method is based preparation of sufficiently pure enantiomers, mainly by chromatography on swollen microcrystalline triacetylcellulose (tac). by this techn...

In this paper, the effects of horizontal stress and dimensions of barrier pillars on the stability of drifts hr been investigated. An elastoplastic hybrid finite/boundary element program has been used. A plastic analysis of stresses in barrier pillars above the drifts in one of the underground coal mines with inclined seams is examined. Computed stresses and safety factor controur lines around ...

Background Despite successful cloning of many mammalian species, the cloning efficiency is extremely low compared to that of IVF raising the possibility of the existence of epigenetic barrier preventing successful cloning. MaterialsAndMethods Using comparative transcriptome analysis comparing transcriptomes of IVF and SCNT embryos and that of donor cells, we identified epigenetic barrier and fi...

This brief deals with the impact of spin-transfer torque magnetic random access memory (STT-MRAM) cell based on double-barrier tunnel junction (DMTJ) performance a two-layer multilayer perceptron (MLP) neural network. The DMTJ-based is benchmarked against conventional single-barrier MTJ (SMTJ) counterpart by means comprehensive evaluation carried out through state-of-the-art device-to-algorithm...

the aim of this study was to investigate the barrier properties of cellulose nanocrystals-pvananocomposites. nanocomposite films with different filler loading levels (3, 6, 9 and 12% by wt) weredeveloped by solvent casting method. the effect of cellulose nanocrystals on the barrier properties ofthe nanocomposites was studied. to this end, moisture absorption, water vapor permeability (wvp),oxyg...

Growth and evolution of germanium (Ge) nanocrystals embedded into a silicon oxide (SiO2) system have been studied based on the Ge content of co-sputtered Ge-SiO2 films using transmission electron microscopy (TEM) and Xray photoelectron spectroscopy (XPS). It was found that when the proportion of Ge relative to Ge oxide is 20%, TEM showed that annealing the samples at 800C for 60 min resulted in...

English main-clause wh-questions form complementiser phrases with wh-words preposed to spec-C position. This is because English wh-words, as verb-complements originally, are strong enough to trigger wh-movement and auxiliary inversion. Persian EFL learners encounter an over-differentiation problem regarding the acquisition of auxiliary inversion rule in English standard questions. Once they hav...