Seed polymerization of tetraethyl orthosilicate in the presence of anionic and cationic polystyrene colloidal spheres

Kinetic analyses are made for the seed polymerization of tetraethyl orthosilicate (TEOS) in the presence of anionic and cationic polystyrene colloidal sphere seeds by turbidity and dynamic light-scattering measurements. Transmission-electron microscopy pictures of the spheres formed are also used. The seed polymerization of TEOS is difficult to take place on the surface of anionic polystyrene spheres (44–212 nm in diameter). On the other hand, the reaction proceeds easily on the cationic polystyrene spheres. Hairy and soft surfaces of polystyrene spheres will disturb the seed polymerization. Furthermore, the electrostatic attraction between the anionic hydrolytic products of TEOS molecules and cationic polystyrene spheres plays an important role for the seed polymerization.     

Mechanism of characteristic shape of resistive transition in Bi2Sr2CaCu2O8 films made by laser evaporation

We measured the temperature dependence of resistivity, (T, H), of Bi₂Sr₂CaCu₂O₈ thin films in magnetic fields. These films have a preferential orientation of the c-axis perpendicular to a surface of the substrate. We could not observe any meaningful anisotropy of the characteristic shape of the resistive transition between two cases of the current flow parallel and perpendicular to the magnetic field in the basal plane. Therefore, it is very difficult to ascribe the broadness to any origin due to the Lorentz force produced by an external current.     

Some considerations on fuzzy conditional inference

In much of human reasoning, the form of reasoning is approximate rather than exact as in ‘A red apple is ripe and this apple is more or less red. Then this apple is more or less ripe.’L.A. Zadeh and E.H. Mamdani suggested methods for such a fuzzy reasoning as an application of fuzzy set theory. The method involves an inference rule and a conditional proposition which contains fuzzy concepts.In this paper we point out that the consequence inferred by their methods does not always fit our intuitions and we suggest the improved methods which fit our intuitions under several criteria.     

Catalytic Reduction of Dinitrogen Monoxide with Methane Over Metal Zeolite Catalysts

Pronounced activities on the reduction of N₂O with CH₄ were observed over Fe-ZSM-5, Pd-ZSM-5, and Pt-ZSM-5 catalysts, respectively. No significant deactivation has been detected over Fe-ZSM-5 in the presence of oxygen.     

New flavonoid glycosides from the leaves of Solidago altissima

Two new flavonoid glycosides kaempferol 3-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (1), and quercetin 3-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (2), together with six known flavonoid glycosides were isolated from the leaves of Solidago altissima L. grown in Kochi of Japan. The structure elucidation of the isolated compounds was performed by acid hydrolysis and spectroscopic methods including UV, IR, ESI-MS, 1D- and 2D-NMR experiments.     

Reversible photopadlocking on double-stranded DNA

We describe a highly efficient method for reversible photocircularization of oligonucleotide (ODN) on a double-stranded DNA template: 5-carboxyvinyl-2'-deoxyuridine-containing ODN was reversibly circularized around the target sequence of the double-stranded plasmid DNA resulting in formation of a catenated plasmid.     

Exploring dynamical electron theory beyond the Born-Oppenheimer framework: from chemical reactivity to non-adiabatically coupled electronic and nuclear wavepackets on-the-fly under laser field

Chemical theory and its application to dynamical electrons in molecules under intense electromagnetic fields is explored, in which we take an explicit account of nuclear nonadiabatic (kinematic) interactions along with simultaneous coupling with intense optical interactions. All the electronic wavefunctions studied here are necessarily time-dependent, and thereby beyond stationary state quantum chemistry based on the Born-Oppenheimer framework. As a general and tractable alternative framework with which to track the electronic and nuclear simultaneous dynamics, we propose an on-the-fly method to calculate the electron and nuclear wavepackets coupled along the branching non-Born-Oppenheimer paths, through which their bifurcations, strong quantum entanglement between nuclear electronic motions, and coherence and decoherence among the phases associated with them are properly represented. Some illustrative numerical examples are also reported, which are aimed at our final goals; real time tracking of nonadiabatic electronic states, chemical dynamics in densely degenerate electronic states coupled with nuclear motions and manipulation and/or creation of new electronic states in terms of intense lasers, and so on. Other examples are also presented as to how the electron wavepacket dynamics can be used to analyze chemical reactions, shedding a new light on some typical and conventional chemical reactions such as proton transfer followed by tautomerization.     

Preparation and utilization of poly(methacryloylsilatrane) as a salt‐dissociation enhancer in PEO‐based polymer electrolytes

Polymers containing silatrane units were prepared by the free radical polymerization of methacryloylsilatrane (MPS), and their conductivities were evaluated. We confirmed that MPS can be polymerized without excessive decomposition of the silatrane units by the radical polymerization initiated by azobisisobutyronitrile. The chemical structure of the polymerized MPS (pMPS) was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopy. The pMPS formed a homogeneous complex with lithium trifluoromethyl sulfonate (LiOTf), although the obtained pMPS/LiOTf complex did not show conductivity. The negligible conductivity was caused by the high glass transition temperature (T_g) of the pMPS matrix, which exceeded 70°C. The pMPS was subsequently utilized as a salt‐dissociation enhancer for the poly(ethylene oxide)‐based polymer electrolyte. MPS was copolymerized with poly[methacryloyl oligo(ethylene oxide)] (pMEO) by free radical polymerization. When the pMEO incorporated a small amount of MPS units (i.e. lower than 15 mol%), the elevation in T_g was not observed, and the conductivity markedly improved. Among the series of copolymers and when compared with pristine pMEO, the copolymer containing 6.3% of MPS units had the maximum conductivity (3.1 × 10^?4 S cm^?1 at 80°C). The Vogel–Fulcher–Tammann fitting parameters showed that the conductivity was improved by the increase in the number of carrier ions. The enhancement in salt dissociation was presumably due to the homogeneous incorporation of polar MPS units. However, when the MPS unit content exceeded 15 mol%, the conductivity was lowered because of the increase in T_g. Copyright © 2013 John Wiley & Sons, Ltd.