Level Statistics for One-Dimensional Schrödinger Operators and Gaussian Beta Ensemble

We study the level statistics for two classes of 1-dimensional random Schrödinger operators: (1) for operators whose coupling constants decay as the system size becomes large, and (2) for operators with critically decaying random potential. As a byproduct of (2) with our previous result (Kotani and Nakano in Festschrift Masatoshi Fukushima, 2013) imply the coincidence of the limits of circular and Gaussian beta ensembles.     

New molecular compound precursor for aluminum chemical vapor deposition

A new type of precursor for aluminum chemical vapor deposition (Al‐CVD) has been developed by mixing dimethylaluminum hydride (DMAH) and trimethylaluminum (TMA). The new precursor has proven itself to be effective for Al‐CVD, where a good selectivity between the Si and the SiO₂ mask, a 3.0 μΩ cm resistivity and a pure Al film with low C and O contamination levels (under 100 ppm) were achieved. Quadrupole mass and infrared absorption analysis have shown that the precursor contains a new molecular compound, consisting of a DMAH monomer and a TMA monomer. The mixture has lower viscosity than DMAH and can be easily bubbled for a stable precursor vapor supply. Copyright © 2000 John Wiley & Sons, Ltd.     

Insertion of Polypyrrole Chains into Montmorillonite Galleries by a Solvent‐Free Mechanochemical Route

Summary: Non‐ionic pyrrole was directly intercalated into unmodified montmorillonite (MMT) and organically modified MMT galleries by adsorption, and subsequently polymerized within the interlamellar spaces by a mechanochemical route under solvent‐free conditions. XRD analysis revealed the successful intercalation of pyrrole into unmodified MMT and organically modified MMT clay galleries by mechanochemical grinding. After in situ polymerization, the XRD and FT‐IR analyses confirmed the insertion of polypyrrole chains between both MMT galleries.

X‐ray powder diffraction patterns of (A) pyrrole‐intercalated MMT and (B) pyrrole‐intercalated C18‐MMT.     

Theory of Shear‐Thickening in Transient Networks of Associating Polymers

Summary: Shear‐thickening phenomena observed in thermo‐reversible gels of telechelic associating polymers are theoretically studied on the basis of the transient network model. Non‐linear tension due to over‐stretching of the middle chain leads to thickening, if the coupling constant g of the end‐chain dissociation rate to the middle chain tension fulfills a certain condition. We give the condition for thickening in terms of the molecular parameters.

The thickening phase diagram: The region below each curve leads to thickening, whereas the region above the curve causes thinning for each molecular weight.