Observations on Solution Crystallization of Poly(vinyl alcohol) in the Presence of Single‐Wall Carbon Nanotubes

PVA/SWNT dispersions yield aloe plant‐like crystals, where the leaves are single crystals templated by PVA coated SWNT. Longer growth times (≈18 months) lead to hexagonal rod‐like crystals. HR‐TEM images show evidence that PVA molecules are aligned parallel to the SWNT axis. WAXD, electron diffraction, and HR‐TEM observations of these aloe plant and hexagonal crystals suggests evidence for possible PVA‐SWNT epitaxy. Wide‐angle and electron diffraction data of these crystals also show that the structure seems to mimic the 2D hexagonal crystal packing of SWNT. PVA lattice images and moiré fringes were also observed in the leaf‐like crystals.

     

The controlled release behavior and pH‐ and thermo‐sensitivity of alginate/poly(vinyl alcohol) blended hydrogels

Poly(vinyl alcohol) (PVA) was blended with sodium alginate (Alg) in various ratios and crosslinked with calcium chloride and made into hydrogel membranes. The dependence of the swelling behavior of these Alg‐Ca/PVA hydrogels on pH was investigated. The temperature‐dependent swelling behavior of the semi‐interpenetrating network (semi‐IPN) hydrogels was examined at temperatures from 2 to 45°C and the enthalpy of mixing (ΔH_mix) was determined at various temperatures. The molecular structure of the hydrogels was studied by infrared spectroscopy and their water structure in the semi‐IPN hydrogels was measured by differential scanning calorimetry (DSC). The influence of Ca²⁺ content on the network structure of Alg‐Ca/PVA hydrogels was investigated in terms of the compressive elastic modulus, effective crosslinking density, and the polymer–solvent interaction parameter based on the Flory theory. The loading of alizarin red S (ARS) followed the Langmuir isotherm mechanism and the release kinetics of ARS from the Alg‐Ca/PVA hydrogels followed the Fickian diffusion mechanism. Copyright © 2008 John Wiley & Sons, Ltd.     

Multi-Walled Carbon Nanotubes as a Novel Promoter of Catalysts for CO/CO2 Hydrogenation to Alcohols

Multi-walled carbon-nanotubes (MWCNTs) are drawing increasing attention in recent years. This material possesses a series of unique features, such as its nanometer-sized channel, highly conductive graphitized tube-wall, sp ²-C-constructed surface, and excellent performance for adsorption and spillover of hydrogen, which make the MWCNTs full of promise to be a novel catalyst support or promoter. This article will review the recent progress in applied research of MWCNTs as a novel promoter in heterogeneous catalysis for active components, including metals and their oxides, with the emphasis on the study and development of MWCNT-promoted catalysts related to CO/CO₂ hydrogenation to alcohols and dimethyl ether based on the recent works carried out in our laboratory.     

Development of enzyme-based bar code-style lateral-flow assay for hydrogen peroxide determination

A unique approach of developing a bar code version of lateral-flow enzymatic-based assay for the semi-quantification of hydrogen peroxide is described. The proposed assay system is mainly composed of a goat anti-mouse IgG-horseradish peroxidase conjugate (Gt anti-M IgG-HRP)-coated nitrocellulose (NC) membrane and a peroxidase substrate pad. Unlike the bar code immunochromatographic assay which depends on the stepwise capture of analyte, the principle of enzyme-based bar code lateral-flow assay is based on the different reaction time on successive lines due to the delay in 3,3′,5,5′-tetramethylbenzidine (TMB) release. Hydrogen peroxide (H₂O₂) acts as a limiting factor which controls the rate of the enzymatic conversion of TMB to blue color complex. The system expresses the concentration of H₂O₂ in micromole range as three distinct ladder bars in 9 min therefore without the need of any reading device. The major advantages of this assay are its easily readable result, and also its simplicity and low-cost in production offers a cheaper alternative for testing those expensive biosensors might not be available to the third world countries. By incorporating with H₂O₂-generating oxidoreductases, the assay can be further extended to detect a variety of analytes with clinical and environmental importance. Glucose was chosen to be the model analyte where the proposed system gave signal response at between 5 μM and 100 μM.     

Σ<Subscript><Emphasis Type="Italic">n</Emphasis>+1</Subscript>-invariant forms of higher degree

In [EGAWA, Y.—SUZUKI, H.: Automorphism groups of Σ _n+1-invariant trilinear forms, Hokkaido Math. J. 11, (1985), 39–47] are explored Σ _n+1-invariant symmetric trilinear forms and their automorphisms. In the paper we generalize their results to d-linear symmetric forms for any d ≥ 3.      

ASYMPTOTIC BEHAVIOR OF SOLUTIONS TO A CLASS OF HIGHER ORDER NONLINEAR INTEGRO-DIFFERENTIAL EQUATIONS WITH DEVIATING ARGUMENTS

In this paper,we study the asymptotic behavior of solutions to a class of higher order nonlinear integro-differential equations with deviating arguments. And some properties of the oscillatory solutions are given. Our results generalize and improve the previous results.     

A Characterization of Higher Rank Symmetric Spaces Via Bounded Cohomology

Let M be complete nonpositively curved Riemannian manifold of finite volume whose fundamental group Γ does not contain a finite index subgroup which is a product of infinite groups. We show that the universal cover is a higher rank symmetric space iff is injective (and otherwise the kernel is infinite dimensional). This is the converse of a theorem of Burger–Monod. The proof uses the celebrated Rank Rigidity Theorem, as well as a new construction of quasi-homomorphisms on groups that act on CAT(0) spaces and contain rank 1 elements. Received: September 2007, Accepted: March 2008     

Two operators related to Marcinkiewicz integrals

In this paper, the authors consider the boundedness of generalized higher commutator of Marcinkiewicz integral μΩ^b, multilinear Marcinkiewicz integral μΩ^A and its variation μΩ^A on Herz-type Hardy spaces, here Ω is homogeneous of degree zero and satisfies a class of L^s-Dini condition. And as a special case, they also get the boundedness of commutators of Marcinkiewicz integrals on Herz-type Hardy spaces.     

高阶Bernoulli数的递推公式及其应用

给出了高阶Bernoulli数的一个递推公式和Nrlund数的一个计算公式,推广了Namias[4],Deeba和Rodriguez[5],Tuenter[6]的结果.