A new organic superconductor, (DODHT)2BF4 x H2O

In addition to two organic superconductors (DODHT)2X [DODHT = (1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene; X = PF6 and AsF6] previously reported by us, the BF4 salt of DODHT containing one water molecule [(DODHT)2BF4 x H2O] has been found to undergo a superconducting transition at 3.2 K under a hydrostatic pressure of 15.5 kbar.     

Incorporating historical information in testing for a trend in Poisson means

An exact conditional test is developed for testing a trend in Poisson means when the historical control information is incorporated into the concurrent control data. An asymptotic conditional test is also developed as an alternative to the Tarone test. Asymptotic gains by the incorporation of the historical information is evaluated.     

On finite element methods for convection dominated phenomena

The aim of this work is to give theoretical justification of several types of finite element approximations to the initial-boundary value problems of first order linear hyperbolic equations. Our approximate scheme is obtained by the piecewise linear continuous finite element method for space variable, x, and the Euler type step by step integration method for time variable, t. An artificial viscosity technique, up-stream type methods are considered within the frame work of L²-theory. The convergence and the error estimate of the approximate solutions to the true one are discussed.     

Polarized (letter ‘8’) memory effects in hetero-systems and non hetero-systems

In order to clarify whether or not the existence of the heterojunction is a necessary condition for the observation of polarized memory effect, experimental observation has been performed on heterosystems which have evaporated thin film on single crystal. The experiments on the reversal of switching polarity have also been carried out. The results suggest that heteojunctions are not essentially related to the polarized memory effect.     

Synthesis of a halogenated clavulone analog

A halogenated clavulone analog 1 which has remarkable antitumor activity was synthesized in a stereoselective and enantioselective manner.     

Low temperature physical properties of the organic conductor, (Dimet)2i3 after thermal treatment

The effect of thermal treatment on the electrical conductivity was studied for a quasi-one-dimensional organic conductor, (DIMET)₂I₃ (DIMET=dimethyl(ethylenedithio)tetrathiafulvalene). After heating the samples up to a temperature between 340 and 370 K, the electric resistivity was measured at low temperature down to 2 K and under pressure up to 1.6 Gpa. (DIMET)₂I₃ shows irreversible decrease in the electric resistivity between 350 and 356 K on heating. It was found that the heating above 350 K suppresses the spin-density-wave transition at 40 K and another metal-insulator transition appears at 18 K. This revised version was published online in August 2006 with corrections to the Cover Date.     

Dopant effect on threshold electric field of antiferroelectric liquid crystal switching

The influence of dopants on the threshold electric field for switching anti-ferroelectric liquid crystals was determined from the optical response curve obtained by using a triangular wave. The effect of dopant concentration on the transition temperatures of the mixtures with a host material was also investigated. The threshold electric field was diminished depending on (i) the chemical structure of the additive and (ii) increasing amounts of the additive. The upper limits of the temperature region of the S*_CA phases also decreased with increasing amount of additive, and these phases disappeared at 40 mol% of additive in all cases. Compound (C) is the most effective with respect to the threshold electric field. It is a two ring compound and has a chiral part similar to that of the host antiferroelectric liquid crystal compound.