Electron emission from crystal surfaces of condensed aromatics under the impact of metastable rare gas atoms

Energy distributions of electrons ejected from polycrystalline surfaces of naphthacene, perylene and coronene by the impact of metastable He ^*, Ne ^* and Ar ^* atoms have been measured. Two types of peaks, which are similar to the “non-moving” and “moving” structures in photoelectron spectra, are observed in each spectrum. The non-moving structures (ca. 1 eV) for perylene and coronene are similar to those in the photoelectron spectra, whereas the relative intensities of the two non-moving structures for naphthacene (0.6 and 1.7 eV) are remarkably different from the corresponding structures in the photoelectron spectrum. The peak positions (but not necessarily their intensities and widths) for the moving structures for all the samples (> 2 eV) agree with those of the corresponding photoelectron spectra. The origin of these moving structures is ascribed to Penning ionization on the solid surface.     

A generalization of the spherical harmonic addition theorem

A generalization of the spherical harmonic addition theorem is proved. The resulting polynomial with four parameters, which corresponds to the Legendre polynomial for the usual spherical harmonic addition theorem, is expressed as four different but equivalent series. Each of them is a finite series of the Gegenbauer polynomials. Thereby the symmetry properties of this polynomial are clarified.     

Benzenthiolate bridged binuclear group 12 metal complexes with TTF fused dithiolate ligand,a new synthetic approach using cluster-cracking reaction

Novel binuclear dithiolate complexes (Me4N)2[M2-(SPh)2(S2TTF(SMe)2)2] (M = Cd and Zn) have been synthesized by a new cluster-cracking method.     

Density functional theory of liquids, some extensions and applications

The density functional theory(DFT) of nonuniform liquids plays an important role in classical many-body theory because of its (mathematical)simplicity and (physical)clarity. Some extensions and applications of DFT, including a new proposal for an m-body hypernetted-chain(HNC) equation for the static structure of liquids are presented.     

Constraint isomorphism and correction algorithms for violations

When a problem can be characterized by different parameter sets, constraints imposed on one parameter set must be consistent with, or isomorphic to, constraints imposed on other parameter sets. When mapping among the parameter sets is not so visibly obvious, one might overlook consistency violations, which have occurred in the past. This paper examines such violations and possible correction algorithms. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Linear stability of homogeneous elongational flow of the upper convected Maxwell fluid

We prove that planar elongational flow of the upper convected Maxwell fluid is linearly stable and analyze the associated spectral problem.     

An analytical molecular orbital approach in tetrathiafulvalene tetracyanoquinodimethane (TTF-TCNQ)

In low-dimensional molecular crystals exhibiting the Peierls instability, intercolumnar interactions play an important role in electrical conduction. In this work, we propose an efficient method based on molecular orbital theory for studying the Peierls instability in molecular crystals composed of mixed-valence complexes. A perturbational approach to general N-merized systems is incorporated and applied to tetrathiafulvalene tetracyanoquinodimethane (TTF-TCNQ) crystals. From the results of the calculations, a mixed state of several commensurate distortions is proposed as another aspect of the incommensurate distortion in TTF-TCNQ under atmospheric pressure, and TTF^+0.5–TCNQ^?0.5 crystal is found to be expected as an electronic conductor under high pressure.     

Multiple sclerosis: Benefits of q-space imaging in evaluation of normal-appearing and periplaque white matter

Introduction

Diffusion tensor imaging (DTI) reveals white matter pathology in patients with multiple sclerosis (MS). A recent non-Gaussian diffusion imaging technique, q-space imaging (QSI), may provide several advantages over conventional MRI techniques in regard to in vivo evaluation of the disease process in patients with MS. The purpose of this study is to investigate the use of root mean square displacement (RMSD) derived from QSI data to characterize plaques, periplaque white matter (PWM), and normal-appearing white matter (NAWM) in patients with MS.

Methods

We generated apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps by using conventional DTI data from 21 MS patients; we generated RMSD maps by using QSI data from these patients. We used the Steel–Dwass test to compare the diffusion metrics of regions of interest in plaques, PWM, and NAWM.

Results

ADC differed (P < 0.05) between plaques and PWM and between plaques and NAWM. FA differed (P < 0.05) between plaques and NAWM. RMSD differed (P < 0.05) between plaques and PWM, plaques and NAWM, and PWM and NAWM.

Conclusion

RMSD values from QSI may reflect microstructural changes and white-matter damage in patients with MS with higher sensitivity than do conventional ADC and FA values.