On numerical asymptotic behavior of finite element solutions for parabolic equations

Summary In this paper, we investigate the numerical asymptotic behavior of the finite element solutions for linear parabolic equations under some appropriate conditions. We also give some results of numerical experiments in the two dimensional problems to indicate the effectiveness of our results.     

Structure of monazomycin,a new ionophohous antibiotic

The structure of monazomycin was determined by degradative study in combination with biosynthetic means using ¹³C-NMR.     

Comparison of luminescent properties of helicene-like bibenzothiophenes with o-carborane and 5,6-dicarba-nidodecaborane

This article describes comparison of the anchoring effect on electronic properties of the helicene-like bibenzothiophene between o-carborane and 5,6-dicarba-nido-decaborane. The o-carborane and nido-decaborane-fused bibenzothiophenes were simultaneously obtained in the same reaction and successfully isolated. Initially, the X-ray single crystal analysis revealed that the helicene-like distorted structure was realized in the nido-decaborane-fused bibenzothiophene. From optical measurements in the solution state, distinct different characteristics depending on the type of anchors were observed. It was summarized that the absorption and luminescent properties originated from weak π-conjugation at the bibenzothiophene moiety in the o-carboranefused compound were obtained, whereas robust π-conjugation and significant emission from the intramolecular charge transfer state were detected from the nido-decaborane-fused compound. These data can be explained by the theoretical results that π-conjugation was restrictedly developed within the bibenzothiophene moiety in frontier orbitals of the o-carborane-fused compound. In contrast, π-conjugation can be constructed even through the distorted bibenzothiophene because of the nido-decaborane unit. Moreover, the intramolecular charge transfer state should be realized because of electronic interaction involving the nido-decaborane unit in the excited state. Furthermore, it was demonstrated that the nido-decaborane-fused compound possessed solid-state emission and mechanochromic luminescent properties. The π-conjugation on the distorted structure supported by the nido-decaborane anchor should play a significant role in suppressing aggregation-caused quenching followed by presenting solid-state emission with stimuli responsiveness.     

Synthesis and conformational analysis of N-aryl-N-(3-thienyl)acetamides

The cis-trans conformational equilibrium of amides is of interest because it can be used to control functional activity. Here, we designed and synthesized a series of N-(3-thienyl)amides in order to study the factors affecting their conformational equilibrium. NMR studies showed that the major conformer of N-methyl-N-(3-thienyl)amide in solution is the E-form (cis form), as is the case for N-methylacetamide. For N-aryl-N-(3-thienyl)amides bearing an N-phenyl moiety, the major conformers differ depending on not only the relative π-electron density of the N-aryl moiety, but also its size. X-ray analysis showed that their solid-state conformational preferences were similar to those in solution.     

Interaction among cluster in chalcogen-rich glasses of Ge1−x(S or Se)x

The composition and pressure dependence of Raman spectra and the optical gap is investigated in order to see interactions among clusters in chalcogen-rich Ge_1?x(S, or Se)_x glasses.     

Large-size β-Ga2O3 single crystals and wafers

Large-size single crystals of β-Ga₂O₃ with 1 inc in diameter have been grown by the floating zone technique. The stable growth conditions have been determined by the examination of the crystal structure. Wafers have been cut and fine polished in the (1 0 0), (0 1 0) and (0 0 1) planes. These were highly transparent in the visible and near UV, as well as electrically conductive, indicating the potential use of β-Ga₂O₃ as a substrate for optoelectic devices operating in the visible/near UV and with vertical current flow.     

Hierarchical decomposition of symmetric discrete systems by matroid and group theories

An algebraic method is proposed for the hierarchical decomposition of large-scale group-symmetric discrete systems into partially ordered subsystems. It aims at extracting substructures and hierarchy for such systems as electrical networks and truss structures.The mathematical problem considered is: given a parametrized family of group invariant structured matricesA, we are to find two constant (=parameter-independent) nonsingular matricesS _r andS _c such thatS _r ^-1 AS _c takes a (common) block-triangular form.The proposed method combines two different decomposition principles developed independently in matroid theory and in group representation theory. The one is the decomposition principle for submodular functions, which has led to the Dulmage—Mendelsohn (DM-) decomposition and further to the combinatorial canonical form (CCF) of layered mixed (LM-) matrices. The other is the full reducibility of group representations, which yields the block-diagonal decomposition of group invariant matrices. The optimality of the proposed method is also discussed.