Development of an amphiphilic resin‐dispersion of nanopalladium and nanoplatinum catalysts: Design,preparation, and their use in green organic transformations

An amphiphilic polymer resin‐dispersion of nanoparticles of palladium was designed and prepared with a view toward use for catalysis in water. The amphiphilic polystyrene‐poly(ethylene glycol) (PS‐PEG) resin‐dispersion of nanoparticles of palladium exhibited high catalytic performance in the hydrodechlorination of chloroarenes under aqueous conditions. The amphiphilic resin‐supported nanopalladium and nanoplatinum particles also catalyzed aerobic oxidation of various alcohols including nonactivated aliphatic and alicyclic alcohols, which is one of the most fundamental and important yet immature processes in organic chemistry, in water under an atmospheric pressure of oxygen gas to form aldehydes, ketones, and carboxylic acids to meet green chemical requirements. Viologen polymer‐supported nanopalladium catalyst realized α‐alkylation of ketones with primary alcohols as the alkylating agents. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 51–65; 2009: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20165     

A Unifying Explanation for the Damping of Turbulence by Additives or External Forces

Recent calculations for the turbulent flow of a suspension of solid spheres in a gas were carried out by solving a Navier Stokes equation for the fluid that recognizes the presence of particles as external point forces. These show that a strong damping of the fluid turbulence can be realized at remarkably small volume fractions. The suggestion is made that the presence of point forces, pseudo-point forces, or added point shear stresses could provide a general explanation for turbulence suppression caused by additives or by the acceleration of a turbulent boundary-layer.     

Associative desorption of adsorbed oxygen promoted by translational energy of incident O2 molecules

Effects of the translational energy of incident oxygen molecules on surface processes from dissociative adsorption to subsequent associative desorption on Pt(1 1 1) have been investigated by means of supersonic molecular beam scattering. The reaction rate of associative desorption increases with the incident translational energy. The enhanced associative desorption can be attributed to nonthermal diffusion of dissociated oxygen, promoted by the translational energy of incoming molecules.     

Stress relaxation under large step equibiaxial elongation for low‐density polyethylene

The stress relaxation under large step equibiaxial elongation for low‐density polyethylene with long‐chain branches revealed that the time‐strain separability holds in relaxation modulus G_B(t, ε_B), and damping function h_B(ε_B) exhibits weaker equibiaxial elongational strain ε_B dependence than that predicted by the Doi–Edwards theory without the independent alignment approximation. Dependencies of damping function h(γ) for step shear deformation and h_B(ε_B) on stretch ratio α of polymer contour length and orientation of a polymer chain in direction of the maximum orientation were evaluated, and it was found that the α dependencies of h(γ) and h_B(ε_B) are different, whereas dependencies of h(γ) and h_B(ε_B) on the orientation coincide fairly well. These results indicate that the damping is dominated by the chain orientation rather than α. This implies that withdrawal of long‐chain branches into tube of a backbone chain occurs when the orientation of the long‐chain branches is large and friction force against the branch point withdrawal is small. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1275–1284, 2009     

Effects of imaging properties on dynamic speckles produced by a set of moving phase screens

Space-time correlation functions have been derived for the time-varying intensities of speckle patterns in image space produced by a series of moving random-phase screens. The time-correlation length, which measures the changing rate of intensity fluctuations, is evaluated from the correlation functions to examine the effects of the imaging properties on the temporal behaviour of the speckles resulting from the multiple scattering. It is shown that the average velocity and velocity dispersion of the phase screens can be measured from the time-correlation length by using imaging systems which have a small and a large point spread at the front focal plane of the systems, respectively. Theoretical results for the relationship between the focal position of the imaging lens and the time-correlation length are also presented.     

Independent Component Analysis of Spectral Absorbance Image in Human Skin

The image of spectral absorbance in human skin is analyzed by independent component analysis. The spectral absorbance image is estimated from an image with red, green, and blue channels. The qualitative information and spatial distribution of the pigments can be extracted by the independent component analysis. It is shown that the extracted absorption characteristics of the pigments are corresponding to those of hemoglobin and melanin.