Improved constraints on D0-D0 mixing in D0 --> K+ pi- decays from the Belle detector

We report the results of a search for D0-D0 mixing in D0 --> K+ pi- decays based on 400 fb(-1) of data accumulated by the Belle detector at KEKB. Both assuming CP conservation and allowing for CP violation, we fit the decay-time distribution for the mixing parameters x and y, as well as for the parameter R(D), the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays. The 95% confidence level region in the (x'2,y') plane is obtained using a frequentist method. Assuming CP conservation, we find x'2 < 0.72 x 10(-3) and -9.9 x 10(-3) < y' < 6.8 x 10(-3) at the 95% confidence level; these are the most stringent constraints on the mixing parameters to date. The no-mixing point (0,0) has a confidence level of 3.9%. Assuming no mixing, we measure R(D) = (0.377 +/- 0.008 +/- 0.005)%.     

Observation of a new DsJ meson in B+-->D0D0K+ decays

We report the observation of a new DsJ meson produced in B+-->D0DsJ-->D0D0K+. This state has a mass of M=2708+/-9(-10)(+11) MeV/c2, a width Gamma=108+/-23(-31)(+36) MeV/c2 and a 1- spin-parity. The statistical significance of this observation is 8.4 sigma. The results are based on an analysis of 449 x 10(6) BB events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.     

Lower closure point of adsorption hysteresis in ordered mesoporous silicas

To examine the nature of the lower closure point of adsorption hysteresis in ordered mesoporous silicas, we measured the temperature dependence of the adsorption-desorption isotherm of nitrogen for three kinds of ordered silicas with cagelike pores and three kinds of ordered silicas with cylindrical pores. The lower closure point pressure of nitrogen in the cagelike pores with sufficiently small necks, that is, the cavitation pressure of a confined liquid, did not depend appreciably on the cage size in the temperature region far away from a hysteresis critical temperature (Tch) but its cage-size dependence was noticeable in the vicinity of Tch. The lower closure point in the cylindrical pores depended on the pore size, and its thermal behavior was totally different from that in the cagelike pores. Nevertheless, the hysteresis critical points of nitrogen in the ordered mesoporous silicas, which are defined as a threshold of temperatures (Tch) and pressure above which reversible capillary condensation takes place in a given size and shape of pores, fell on a common line in a temperature-pressure diagram regardless of the pore geometries. We consider this finding as evidence that capillary evaporation in the cylindrical pores follows a cavitation process in the vicinity of Tch in the same way as that in the cagelike pores and also that the low limit of the hysteresis loop that has been long recognized since 1965 is due to the occurrence of a vapor bubble in a stretched metastable liquid confined to the pores with decreasing pressure (cavitation).     

Excellent Redox Properties of Poly(thienylphenylamine)s

Triphenylamines with thienyl groups are electro‐oxidatively polymerized to yield the corresponding branched polymers on an electrode. The resulting polymers show significantly better redox properties, such as redox activity, catalytic activity, and conductivity when compared with for example the linear polymeric analog. The good properties of the branched polymers are based on the higher electronic conductivity (2–6 S/cm), since the branching provides multiple routes for charge carriers. The redox‐active polymers show high capacity (ca. 40 mC/cm²) and catalytic activity for the electron transfer of ferrocene on the electrode.     

Development of a new software for the X-ray structural analysis of polymer crystals by utilizing the X-ray imaging plate system

A software and some useful tools have been developed for identifying individual x-ray reflectional peaks recorded with an x-ray imaging plate system. These techniques were applied to analyze the crystal structure of uniaxially oriented polymer samples. Characteristic features of the present method may be summarized as follows. (1) The indexing of the observed reflections and the determination of the unit cell parameters can be made easily on the display of the computer. (2) The integrated intensity of the individual component of the overlapped reflections can be evaluated quantitatively through the curve separation technique. The R_merge's for the equivalent reflections were 5–6%, indicating the exact evaluation of the integrated intensities. (3) The thus obtained reflectional data were successfully utilized for the extraction of the initial structural models by the direct method. The actual applications have been made for orthorhombic polyethylene, trigonal polyoxymethylene, and isotactic polybutene-1, giving the refined crystal structures including even the positions of hydrogen atoms in some cases. The reliability factors were 12, 5, and 15%, respectively, for these three polymer cyrstals. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1677–1700, 1997     

3D-CT(Computer Tomography) Measurement of an Instantaneous Density Distribution of Turbulent Flames with a Multi-Directional Quantitative Schlieren Camera (Reconstructions of High-Speed Premixed Burner Flames with Different Flow Velocities)

In order to provide a suitable technique for 3D observation of high speed turbulent flames, non-scanning 3D-CT(Computer Tomography) technique using a multi-directional quantitative schlieren system with flash light source, is proposed for instantaneous density distribution of unsteady premixed flames. This “schlieren 3D-CT” is based on (i)simultaneous acquisition of flash-light schlieren images taken from numerous directions, and (ii) 3D-CT reconstruction of the images by an appropriate CT algorithm. In this paper, first, as a preliminary research, 3D-CT reconstruction of non-axisymmetric steady flame is made with a single-directional quantitative schlieren system. Next, with custom-made 20 directional schlieren camera, instantaneous density distributions of a high-speed turbulent flames of nozzle exit velocities of 8.0 and 10.0 m/s has been CT-reconstructed. The 3D-views of the reconstructed flame front shape clearly give the information of the flame structure with fine scale corrugations. Based on the distributions, area-enlargement rates of the flame front area are derived, and investigated.     

Zinc-metal promoted selective α-haloacylation and gem-bisacylation of alkyl aldehydes in the presence of chlorotrimethylsilane

Treatment of a mixture of alkyl aldehydes (1) with acid chlorides (2) in the presence of zinc metal powder and a catalytic amount of chlorotrimethylsilane (TMSCl) in dichloromethane brought about highly facile and effective coupling to give selectively the corresponding α-haloacylation and gem-bisacylation products, α-haloalkyl carboxylates and 1,1-dicarboxylates (acylals), in good to excellent yields.