Freezing of a stripe liquid

The existence of a stripe-liquid phase in a layered nickelate, La(1.725)Sr(0.275)NiO(4), is demonstrated through neutron scattering measurements. We show that incommensurate magnetic fluctuations evolve continuously through the charge-ordering temperature, although an abrupt decrease in the effective damping energy is observed on cooling through the transition. The energy and momentum dependence of the magnetic scattering are parametrized with a damped-harmonic-oscillator model describing overdamped spin waves in the antiferromagnetic domains defined instantaneously by charge stripes.     

Morphology of Polystyrene Core–dPoly(ethylene oxide) Shell Arborescent Copolymer Micelles from Small-Angle Neutron Scattering Analysis

Arborescent (dendrigraft) copolymers with a branched polystyrene (PS) core grafted at the chain termini with deuterated poly(ethylene oxide) segments (PS-dPEO) were characterized in benzene and acetone by small-angle neutron scattering measurements using the contrast matching technique. While copolymers incorporating a G1 (twice-grafted) PS core aggregated to some extent, the portion of the scattering curve corresponding to non-aggregated copolymer molecules could still be analyzed to determine the shape and segment radial density profile for core and shell. These were derived from the pair distance distribution function P(r) and the scattering length density contrast profile Δρ(r) = ρ(r) ? ρ(solvent), obtained by the indirect Fourier transformation and deconvolution methods. The profiles obtained for the G1 copolymer are consistent with a well-defined PS core–dPEO shell morphology, only observed previously for upper generation (G4) polymers with deuterated PS (dPS) chains grafted randomly on arborescent PS substrates. Detailed morphological analysis could not be carried out for an analogous G3 arborescent PS copolymer terminally grafted with dPEO segments due to extensive aggregation in both solvents.     

Coherent manipulation of electronic States in a double quantum dot

We investigate coherent time evolution of charge states (pseudospin qubit) in a semiconductor double quantum dot. This fully tunable qubit is manipulated with a high-speed voltage pulse that controls the energy and decoherence of the system. Coherent oscillations of the qubit are observed for several combinations of many-body ground and excited states of the quantum dots. Possible decoherence mechanisms in the present device are also discussed.     

Pattern of the Activity of (0.5–15)%CoO/CeO2 Catalysts in Carbon Monoxide Oxidation with Oxygen in Excess Hydrogen

Kinetics and Catalysis - Samples of (0.5–15)%CoO/CeO2, Co3O4, and CeO2 have been studied in the oxidation of CO to CO2 in a CO+O2+H2 mixture in a range of 40–340°C. The highest...     

Effect of matrix polymerization conditions on the structure and adsorption properties of porous polymers on the basis of divinylbenzene,acrylonitrile, and methyl methacrylate

A comparative study was carried out on the matrix polymerization of divinylbenzene, acrylonitrile, and methyl methacrylate in SBA-15 silica mesoporous molecular sieves. The occupancy of the matrix mesopores by the starting monomer, the medium, the polymerization temperature and time as well as the means of removing the exotemplate were all found to affect the spatial organization and porous structure of the polymer materials. Surplus occupancy of the mesopores by the monomer (1–1.5), polymerization in vacuum, and an alkaline method for matrix removal were found to be optimal. IR spectroscopy was used to find the conversion of the starting polymer by following the relative change in intensity of the vinyl group bands. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 44, No. 6, pp. 371–375, November–December, 2008.     

Heritability and linkage study on heart rates in a Mongolian population

Elevated heart rate has been proposed as an independent risk factor for cardiovascular diseases, but their interrelationships are not well understood. In this study, we performed a genome-wide linkage scan in 1,026 individuals (mean age 30.6 years, 54.5% women) from 73 extended families of Mongolia and determined quantitative trait loci that influence heart rate. The DNA samples were genotyped using deCODE 1,039 microsatellite markers for 3 cM density genome-wide linkage scan. Correlation analysis was carried out to evaluate the correlation of the covariates and the heart rate. T-tests of the heart rate were also performed on sex, smoking and alcohol intake. Consequently, this model was used in a nonparametric genome-wide linkage analysis using variance component model to create a multipoint logarithm of odds (LOD) score and a corresponding P value. In the adjusted model, the heritability of heart rate was estimated as 0.32 (P<.0001) and a maximum multipoint LOD score of 2.03 was observed in 77 cM region at chromosome 18. The second largest LOD score of 1.52 was seen on chromosome 5 at 216 cM. Genes located on the specified locations in chromosomes 5 and 18 may be involved in the regulation of heart rate.     

Cyclic and acyclic S2O2 donor-type ionophores. Ion-pair extraction and transport of Ag(I) picrate, and X-ray confirmation of existence of the ion-pair complex

Extraction and transport behaviors of isomeric oxathia macrocycles (L₂, ortho-; L₃, meta- and L₄, para-isomer) and their structure related open-chain compound (L₁) towards Ag(I) picrate have been examined. From the plot of log (D_Ag(I)/[pic⁻]) vs. log [L]₀ for all of the ionophores were linear with slope near unity, thereby confirming the 1:1:1 complex formations of Ag(I)/ligand/picrate ion to be extracted into the dichloromethane phase. The extractability of an acyclic ionophore was superior to those of the corresponding cyclic ones. In membrane transport experiments, the slow rate of release of Ag(I) from the membrane into the receiving phase seems to be responsible for lower transport efficiency. Upon addition of sodium thiosulfate as a stripping reagent in receiving phase, the efficiency of transport is significantly enhanced in the order of L₁ (acyclic)>L₂ (ortho-)>L₃ (meta-)>L₄ (para-) in accordance with those of log K_ex values. It is hypothesized that the ion-pair complexation of L₁ in extraction step would be more favorable in extraction and transport of Ag(I). Its structure have been confirmed by X-ray diffraction analysis of [Ag(L₁)pic], where L₁=1,10-bis(mercaptobenzylyl)-4,7-dioxadecane.     

Synthesis and spectral characteristics of the combined ligand copper complex with proline and corazole

Synthesis of the combined ligand complex of copper(II) prolinate bis(1,5-pentamethylenetetrazole) [Cu(PMT)₂](Pro)₂ was carried out. The product is interesting as a biologically active compound. It is obtained by reaction of copper carbonate with proline followed by further reaction with corazole. The composition and structure of the complex were confirmed by elemental analysis and data of UV, IR, and ¹H NMR spectroscopy. The complex was characterized in detail by the method of circular optical dichroism.     

Ab initio calculation of structure and transport properties of He…X (X = Zn, Cd, Hg) van der Waals complexes

The ground state ab initio CCSD(T) potential curves using various basis sets (aug-cc-pVXZ-PP (X = D, T, Q, 5)) is obtained for the dimers of helium with IIb group metals. The effect of the position of the (mid) bond-functions on the interaction energy is discussed. A Symmetry Adapted Perturbation Theory decomposition of the interaction energy is provided and the trends in the dimer stabilizing and destabilizing contributions are depicted. The spline fitted potential curves are applied together with rigorous statistical formulae in order to obtain the transport coefficients (viscosity coefficients, diffusion coefficients) and the second virial coefficient both for pure constituents and mixtures. The obtained theoretical results are compared with available experimental data. Molecular dynamics is used to obtain reliable values of the diffusion coefficients for all the systems under study.