Effect of component ratio of binary organic solvent on sorption of phenols by silica

Chromatography is employed to measure the adsorption constants of hydroxybenzenes on SiO₂ in a low-concentration region at varied compositions of a binary organic solvent (n-hexane-ethyl acetate). It is shown that the Henry constants vary depending on the polar-to-nonpolar component ratio in the binary solvent and the number and position of hydroxyl groups in phenol molecules. It is found that the absolute values of changes Δ(ΔG) in the free energy considerably increase as the content of ethyl acetate in the mixtures diminishes, with the ratios between the Δ(ΔG) values of ortho-, meta-, and para-isomers remaining practically unchanged. The data obtained can be used to optimize the processes of the adsorption separation of mixed polyphenols and the isolation of natural phenolic compounds on a preparative scale.     

Structures and sorption properties of the coordination polymers built up of 3d metal carboxylate polynuclear complexes

The reaction of trinuclear acetate complexes Fe₂MO(AcO)₆(H₂O)₃ (M = Ni²⁺, Co²⁺) with 4,4′-bipyridine (bpy) results, depending on the reaction conditions, in porous coordination polymers with the composition Fe₂MO(AcO)₆(bpy)_1.5 (with retention of the metal core Fe₂MO(AcO)₆) or nonporous coordination polymers with the composition M₂(AcO)₄(bpy)₂ (with destruction of the metal core Fe₂MO(AcO)₆). The adsorption and desorption properties of the compounds Fe₂MO(AcO)₆(bpy)_1.5 with respect to nitrogen and hydrogen were studied. The reaction of hexanuclear benzoate complex Mn₆O₂(PhCOO)₁₀(MeCN)₄ with bpy or trans-1,2-bis(4-pyridyl)ethylene (bpe) in DMF results in destruction of the metal core Mn₆O₂(PhCOO)₁₀ and formation of nonporous coordination polymers, while the pivalate complex Mn₆O₂(Piv)₁₀(EtOH)₃(HPiv) under the same conditions gives rise to the coordination polymer containing Mn₆O₂(Piv)₁₀ structural blocks.     

Modulation of ultrasonic pulses by a magnetized magnetic colloid

The dependence of the shape of an ultrasonic pulse transmitted through a magnetized magnetic colloid on the angle between the wave vector and the magnetic induction vector is investigated.     

Structural-acoustic analysis of a nanodispersed magnetic fluid

Results of investigations into the dispersed composition of a magnetic fluid based on the measured dependence of the amplitude of the acousto-magnetic effect on the magnetic field strength are considered. The results obtained are compared with the data of atomic force microscopy and magneto-granulometric analysis.     

Viscosity of a Magnetic Fluid in a Strong Magnetic Field

Acoustical Physics - The paper presents an estimate for the viscosity and its increment (“magneto-viscous” effect) in a thin wall layer of a magnetic fluid column oscillating in a tube...     

Elasticity of an Air Cavity in a Magnetic Fluid on an Annular Magnet Segment with Changing Magnetic Field Sign

Russian Physics Journal - The paper discusses the results of experimental research on air cavity capture by magnetic fluid and elasticity of the produced oscillatory system on an annular magnet...     

Tissue and fixative dependent shifts of delta13C and delta15N in preserved ecological material

Carbon and nitrogen stable isotope analyses are routinely used to investigate aquatic food webs, and have potential application in retrospective investigations using archived materials. However, such analyses assume that storage does not alter isotopic signatures of materials preserved, or that changes in isotopic composition during storage are predictable. Here we examine preservation shifts on cod (Gadus morhua) muscle, roe and liver tissue over 21 months following preservation in 80% ethanol, in 4% formaldehyde, and by freezing. Preservation shifts were not consistent among tissues. High protein tissues exhibited greater delta(15)N shifts than low protein tissues in 4% formaldehyde, while greater delta(13)C shifts occurred in relatively higher fat tissues when preserved in alcohol. Freezing did not change isotopic signatures. Responses of delta(15)N and delta(13)C are explained by differences in the preservative's isotopic signature and the reaction properties and biochemical composition of the tissues preserved. The results clarify some of the processes that lead to isotopic change during preservation.     

The e + e −→π0π0γ process below 1.0 GeV

The e ⁺ e ^?→π⁰π⁰ γreaction was studied in the energy range 0.36–0.97 GeV on a VEPP-2M e ⁺ e ^? collider with an SND detector. The decay probabilities were found to be B(ω→ π⁰π⁰γ)= (7.8 ±2.7±2.0)×10^?5 and B(π→ π⁰π⁰γ)= (4.8 _?1.8 ^+3.4 ±0.2)×10^?5.