Stochastic heating of ions in a modulated electron beam-plasma system

A modulation of an electron beam density at frequencies lower than an ion cyclotron frequency enhanced the low frequency instability of broad band and heated plasma ions in a beam-plasma system. The heating of ions is explained by the stochastic process of a weakly turbulent plasma.     

Treatment of ion exchange membranes to decrease divalent ion permeability

In the electrodialysis process for concentrating sea water, the addition of a small amount of the polycationic reagent Nonisold into the sea water feed results in a reduction of divalent cation permeability relative to that of monovalent cations. This is due to the formation of a reagent layer on the surface of the cation-exchange membrane. Divalent cations require greater energy to pass over the potential barrier at the reagent layer than do monovalent cations. The relationship between the height of the potential barrier and the ratio of ionic fluxes or the permselectivity coefficient is deduced on the basis of a kinetic-controlled mechanism of uptake of ions from the solution, and the height of the potential barrier is estimated from the experimental results. The difference between the potential barrier for divalent cations and that for monovalent cations may reach up to about 10 kJ/mol.     

Acyclic stereocontrol via asymmetric [2,3]-Wittig rearrangement with high enantio- and erythro-selectivity and its use in the chiral synthesis of insect pheromones

Such an asymmetric [2,3]-Wittig variant that is both highly enantio- and erythro-selective is described within the context of the chiral synthesis of the insect pheromones, (3$\text{S}$, 4$\text{S}$)-4-methyl-3-heptanol and ($\text{S}$)-4-methyl-3-heptanone.     

Selective cleavage of polycyclic cyclopropanes by electrochemical oxidation

Anodic oxidation in acetic acid of polycyclic cyclopropanes, namely tricyclene, cyclofenchene, and longicyclene, followed by hydrolysis brought about stereo- and regioselective formation of the corresponding homoallylic alcohols as the main product in good yields.     

Λc5He and Λc9Be charmed nuclei versus Λ5He and Λ9Be hypernuclei

A comparative study is made for _Λc⁵He and _Λc⁹Be charmed nuclei versus _Λ⁵He and _Λ⁹Be hypernuclei. The Λ_c(Λ)+α and Λ_c(Λ)+α+α systems are treated in a microscopic way. Within certain range of the Λ_cN interaction strength, the energy properties of Λ_c+α and Λ_c+α+α are calculated and discussed. Similarity between the energy spectra of the noted charmed nuclei and hypernuclei is suggested.     

Escape rate of two-dimensional electrons on liquid helium surface

Escape rate of two-dimensional electrons on liquid helium surface is measured. A strong dependence of the escape rate on the surface electron density suggests that the surface electron system is in a “liquid” state.     

On finsler spaces with kropina metric

The curvature tensors and other important tensors of a Finsler space with Kropina metric are studied. We find conditions for such a space to be affinely connected in Berwald's sense.     

Vanadium-catalyzed pinacol coupling reaction in water

A catalytic pinacol coupling using water as a solvent was performed by a catalytic amount of vanadium(III) chloride and metallic Al as a co-reductant. A combination forms a binary catalytic system, being in sharp contrast to the reaction in organic solvent, which requires a chlorosilane as an additive. Various aromatic aldehydes underwent the reductive coupling to give the corresponding 1,2-diols in moderate to good yields.