Ion Beam Driven Ion Cyclotron Double Layers

We present here a self consistent theory of small amplitude double layers associated with electrostatic ion cyclotron waves in a plasma containing hot electrons, cold ions and traversed by an ion beam. It has been shown that compressive type of double layers solution exists when θ_b (beam temperature) < α_b (beam concentration) < 1.     

Ion Product of Pure Water Characterized by Physics-Based Water Model

Pure water has been characterized for nearly a century, by its dissociation into hydronium (H₃O)¹⁺ and hydroxide (HO)^1- ions. As a chemical equilibrium reaction, the equilibrium constant, known as the ion product or the product of the equilibrium concentration of the two ion species, has been extensively measured by chemists over the liquid water temper-ature and pressure range. The experimental data have been nonlinear least-squares fitted to chemical thermodynamic-based equilibrium equations, which have been accepted as the industrial standard for 35 years. In this study, a new and statistical-physics-based water ion product equation is presented, in which, the ions are the positively charged protons and the negatively charged proton-holes or prohols. Nonlinear least squares fits of our equation to the experimental data in the 0-100 ℃ pure liquid water range, give a factor of two better precision than the 35-year industrial standard.     

Reagenzien zar Identifizierung von Aldehyden und Ketonen.

Ohne Zusammenfassung     

Adsorption of water on JSC‐1A (simulated moon dust samples)—a surface science study

JSC‐1a (a simulated lunar dust sample) supported on a silica wafer (SiO₂/Si(111)) has been characterized by scanning electron microscopy (SEM), energy dispersive x‐ray (EDX) spectroscopy, and Auger electron spectroscopy (AES). The adsorption kinetics of water has been studied primarily by thermal desorption spectroscopy (TDS) and in addition by collecting isothermal adsorption transients. Blind experiments on the silica support have been performed as well. JSC‐1a consists mostly of aluminosilicate glass and other minerals containing Fe, Na, Ca, and Mg, as characterized in detail in prior studies, for example, at NASA. The particle sizes span the range from a few micrometers up to 100 µm. At small exposures, H₂O TDS is characterized by broad (100–450) K structures; at large exposures, distinct TDS peaks emerge, which are assigned to amorphous solid water (ASW) (145 K) and crystalline ice (CI) (165 K). Water dissociates on JSC‐1a at small exposures but not on the bare silica support. Coadsorption TDS data (alkane–water mixtures) indicate that rather porous condensed ice layers form at large exposures, with the mineral particles acting most likely as nucleation sites. At thermal impact energies, the initial adsorption probability amounts to 0.92 ± 0.05. It is evident that the drop‐and‐dry technique, developed in studies about nanoparticles/tubes, can be extended to obtain samples for surface science studies based on powders consisting of particles with rather large diameters. Copyright © 2008 John Wiley & Sons, Ltd.     

Aldehyde

Ohne Zusammenfassung     

Unbounded sequences of stable limit cycles in the delayed Duffing equation: an exact analysis

Nonlinear Dynamics - The delayed Duffing equation $${\ddot{x}}(t)+x(t-T)+x^3(t)=0$$ is shown to possess an infinite and unbounded sequence of rapidly oscillating, asymptotically stable periodic...     

Amine mediated proton transfer reaction and C-Cl bond activation of solvent chloroform by a trinuclear copper(II) complex of a glucopyranosylamine derived ligand

An amine mediated C-Cl bond activation process of the solvent chloroform has been explored by a coordinatively labile trinuclear Cu(II) complex, [Cu3(L1)2(MeOH)(H2O)] (1), derived from N-(3-tert-butyl-2-hydroxybenzylidene)-4,6-O-ethylidene--D-glucopyranosylamine (H3L1). The effect of activation is extremely high with methylamine, resulting in the formation of [Cu(MeNH2)5]Cl2 (2) and [Cu(L2)2] (3; HL2 = 2-tert-butyl-6-[(methylimino)methyl]phenol), however, under identical conditions it is moderate with ethylamine resulting in the isolation of crystals of the intermediate amine bound trinuclear copper(II) complex, [Cu3(L1)2(EtNH2)2(MeOH)2] (5), which was further converted into the mononuclear complex, [Cu(HL1)(EtNH2)] (6), in a novel crystal-to-crystal transformation. The successive isolation of the ethylamine-bound tri- and mononuclear complexes, 5 and 6, supported the occurrence of proton transfer reactions, which might be a key step in C-Cl bond activation. The primary and secondary amines, 2-aminomethylpyridine, N,N-dimethylethylenediamine, and 1,4,7-triazacyclononane, also having chelating features further enhance the rate of activation. No activation has been noted in the case of triethylamine and N,N,N,N-tetramethylethylenediamine. Formation of a carbene-trapped compound, 2,6-xylyl isocyanide, was confirmed in the reaction of complex 1 with 1,4,7-triazacyclononane and 2,6-xylidine in CHCl3, suggesting that the C-Cl bond cleavage led to the generation of dichlorocarbene. In addition, the mononuclear complex 6 has been transformed into a homotrinuclear complex [Cu3(L1)2(MeOH)2] by treatment with Cu(II) ions in MeOH/CHCl3, suggesting the possibility that the former could be regarded as a suitable metalloligand for heterotrimetallic complex synthesis.