Pressure effect on the electrical conductivity and superconductivity of beta-(BDA-TTP)2I3

The pressure-induced electrical conductivity properties of beta-(BDA-TTP)2I3 have been investigated; the salt exhibits a dramatic change in the conductivity behaviour above ca. 10 kbar and undergoes a superconducting transition with an onset near 10 K.     

Water-solubilization of nucleotides-coated single-walled carbon nanotubes using a high-speed vibration milling technique

[reaction: see text] Pristine single-walled carbon nanotubes (SWNTs) and nucleotides mixed using a mechanochemical high-speed vibration milling technique (HSVM) are soluble in an aqueous solution, and the solubilities of SWNTs depend significantly on the number of phosphate groups and the kinds of bases employed.     

Compensation of effective field in the field-induced superconductor kappa-(BETS)2FeBr4 observed by 77Se NMR

We report results of 77Se NMR frequency shift in the normal state of the organic charge-transfer salt kappa-(BETS)2FeBr4 which shows magnetic field-induced superconductivity (FISC). From a simple mean-field analysis, we determined the field and the temperature dependences of the magnetization m(pi) of the pi conduction electrons on BETS molecules. We found that the Fe spins are antiferromagnetically coupled to the pi electrons and determined the exchange field to be J = -2.3T/microB. The exchange field from the fully saturated Fe moments (5 microB) is compensated by an external field of 12 T. This is close to the central field of the FISC phase, consistent with the Jaccarino-Peter local field-compensation mechanism for FISC [Phys. Rev. Lett. 9, 290 (1962)].     

The effects of exciton-diffusion blocking layers on pentacene/C60 bulk heterojunction solar cells

Organic thin film solar cells, with structures based on pentacene/C₆₀ bulk heterojunctions, have been fabricated and characterized. The effect of introducing an exciton-diffusion blocking layer (EBL) of 3,4,9,10-perylenetetracarboxylic dianhydride, between the active layer and the metal layer in the solar cell, was investigated. It was shown that optimized structures containing EBLs resulted in an improvement in solar cell conversion efficiencies. The energy levels of the molecules were calculated and are subsequently discussed.     

Fabrication and characterization of C60/tetrathiafulvalene solar cells

Fabrication and characterization of C₆₀/tetrathiafulvalene solar cells was carried out. Photovoltaic properties of bulk-hetero and heterojunciotn solar cells were investigated by light-induced current vs. voltage curves and optical absorption. Transmission electron microscopy (TEM) image, X-ray and electron diffraction showed that the bulk-heterojunction film had the microstructure of C₆₀ crystal structure with TTF phase. Heat treatment of the heterojunction film with tetraethylsilane improved the photovoltaic performance, yielding a slight increase of conversion efficiency. This result would be originated in improvement of microstructure around inner interface between the both crystal phases. Mechanisms of the photovoltaic properties were discussed on the basis of the experimental results.     

New dimeric and monomeric chromanones,gonytolides D–G,isolated from the fungus Gonytrichum sp.

In the course of the screening of innate immune regulators from natural resources, we isolated new dimeric and monomeric chromanones, gonytolides D–G (4–7), from Gonytrichum sp. along with a known innate immune promoter, gonytolide A (1). The structures of these compounds were determined by spectral analysis, chemical conversion, and biogenetic consideration. The compounds 4–7 were evaluated on the innate immune response, indicating that the 8,8′-linked bischromanone rings were crucial for innate immune-promoting activity.     

Bipancyclic properties of Cayley graphs generated by transpositions

Cycle is one of the most fundamental graph classes. For a given graph, it is interesting to find cycles of various lengths as subgraphs in the graph. The Cayley graph on the symmetric group has an important role for the study of Cayley graphs as interconnection networks. In this paper, we show that the Cayley graph generated by a transposition set is vertex-bipancyclic if and only if it is not the star graph. We also provide a necessary and sufficient condition for to be edge-bipancyclic.     

On some inequalities for Doob decompositions in Banach function spaces

Let ${\Phi : \mathbb{R} \to [0, \infty)}Let F: \mathbbR ? [0, ￥){\Phi : \mathbb{R} \to [0, \infty)} be a Young function and let f = (f_n)_n ? \mathbbZ₊{f = (f_n)_n\in\mathbb{Z}_{+}} be a martingale such that F(f_n) ? L₁{\Phi(f_n) \in L_1} for all n ? \mathbbZ₊{n \in \mathbb{Z}_{+}} . Then the process F(f) = (F(f_n))_n ? \mathbbZ₊{\Phi(f) = (\Phi(f_n))_n\in\mathbb{Z}_{+}} can be uniquely decomposed as F(f_n)=g_n+h_n{\Phi(f_n)=g_n+h_n} , where g=(g_n)_n ? \mathbbZ₊{g=(g_n)_n\in\mathbb{Z}_{+}} is a martingale and h=(h_n)_n ? \mathbbZ₊{h=(h_n)_n\in\mathbb{Z}_{+}} is a predictable nondecreasing process such that h ₀ = 0 almost surely. The main results characterize those Banach function spaces X such that the inequality ||h_￥||_X ￡ C ||F(Mf) ||_X{\|{h_{\infty}}\|_{X} \leq C \|{\Phi(Mf)} \|_X} is valid, and those X such that the inequality ||h_￥||_X ￡ C ||F(Sf) ||_X{\|{h_{\infty}}\|_{X} \leq C \|{\Phi(Sf)} \|_X} is valid, where Mf and Sf denote the maximal function and the square function of f, respectively.     

Over-doping of Tl2Ba2CuO6 due to charge transfer Tl-(Cu-O)

Superconductivity was observed in La substituted Tl₂Ba₂CuO₆. Both T_c and unit cell dimension, a, increase with increasing La concentration, indicating that an over-doping state in Tl₂Ba₂CuO₆, which was due to charge transfer Tl^3−t-(Cu-O)^p as supported from XPS measurements, was relieved by La substitution for Ba.