Search for CP violation in the decay B0-->D*+/-D-/+

We report a search for CP-violating asymmetry in B0-->D(*+/-)D-/+ decays. The analysis employs two methods of B0 reconstruction: full and partial. In the full reconstruction method all daughter particles of the B0 are required to be detected; the partial reconstruction technique requires a fully reconstructed D- and only a slow pion from the D(*+)-->D0pi(+)(slow) decay. From a fit to the distribution of the time interval corresponding to the distance between two B meson decay points we calculate the CP-violating parameters and find the significance of nonzero CP asymmetry to be 2.7 standard deviations.     

Observation of radiative B-->phi K gamma decays

The radiative decay B-->phi K gamma is observed for the first time. The branching fraction for the charged B--->phi K- gamma decay mode is measured to be B(B--->phi K- gamma)=(3.4+/-0.9+/-0.4)x10(-6). The photon energy distribution for the B--->phi K- gamma decay is presented. The signal for the neutral B(0)-->phi K(0)gamma decay mode is not statistically significant and an upper limit, B(B(0)-->phi K(0)gamma)<8.3x10(-6) at 90% C.L., is set. The analysis is based on a data set of 90 fb(-1) collected by the Belle experiment at the e(+)e(-) asymmetric collider KEKB.     

Measurement of branching fractions for B-->eta(c)K(*) decays

We report measurements of branching fractions for charged and neutral B-->eta(c)K decays where the eta(c) meson is reconstructed in the K(0)(S)K+/-pi(-/+), K+K-pi(0), K(*0)K-pi(+), and pp; decay channels. The neutral B0 channel is a CP eigenstate and can be used to measure the CP violation parameter sin(2phi(1). We also report the first observation of the B0-->eta(c)K(*0) mode. The results are based on an analysis of 29.1 fb(-1) of data collected by the Belle detector at KEKB.     

Thermomechanical Analysis of Polysaccharide Hydrogels in Water

Application of thermomechanometry to the measurement of hydrogels containing a large amount of water was carried out by static and dynamic methods. A thermomechanical analyzer (TMA) equipped with a quartz compression probe immersed in water was used. Polysaccharide hydrogels containing ca 98% water were measured. Creep of hydrogels in water was analyzed in a stress range from 1.04⋅10³ to 5.2⋅10³ Pa and loading rate from 0.3⋅10³ to 3.0⋅10³ Pa min⁻¹.Stress relaxation was measured in compressed ratio range from 0.02 to 0.45 m m⁻¹ and in compressing rate was 0.09 to 0.15 m m⁻¹ min⁻¹. Dynamic viscoelasticity was measured by TMA when dynamic Young’s modulus which was larger than 1⋅10⁴ Pa in frequencies ranging from 0.02~0.2 Hz. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mössbauer studies of mixed-valence spin-crossover iron complexes with a hexadentate tripod ligand

The spin-crossover behaviors of mixed-valence iron compounds [Fe^IIH₃L][Fe^IIIL](NO₃)₂ (1) and [Fe^IIH₃L^Me][Fe^IIIL^Me](NO₃)₂ (2) have been investigated by ⁵⁷Fe Mössbauer spectroscopy, where H₃L is a hexadentate N₆ tripod ligand containing three imidazole groups and H₃L^Me is its 2-methylimidazole derivative. Deconvolution analyses of the Mössbauer spectra revealed that a two-step SCO (LS Fe^II–LS Fe^III→HS Fe^II–LS Fe^III→HS Fe^II–HS Fe^III) proceeds in each compound on elevating the temperature. Compound 2 exhibited lower spin-transition temperatures than 1. “Frozen-in effect” was observed below 120 and 50 K for 1 and 2, respectively.     

An experimental study on effects of solid concentration and ζ-potential on pseudoplastic flow of suspensions

The pseudoplastic flow of suspensions, alumina or styrene-acrylamide copolymer particles in water or an aqueous solution of glycerin has been studied by the step-shear-rate method. The relation between the shear rate,D, and the shear stress,, in the step-shear-rate measurements, where the state of dispersion was considered to be constant, was expressed as = AD ^1/2 +CD. The effective solid volume fraction,ø _F, andA were dependent on the shear rate and expressed byø _F =aD ^b andA = D . Combining the above relations, the steady flow curve was expressed by = D ^{1/2 +} + ₀ (1 – a D ^b/0.74)^–1.85 D, where ₀ is the viscosity of the medium.With an increase in solid volume fraction and a decreases in the absolute value of the-potential, the flow behavior of the suspensions changed from Newtonian ( = = b = 0), slightly pseudoplastic ( = b = 0), pseudoplastic ( = 0) to a Bingham-like behavior.The change in viscosity of the medium had an effect on the change in the effective volume fraction.     

Impact of cell-voltage on energy and power performance of supercapacitors with single-walled carbon nanotube electrodes

We report the energy and power voltage-dependencies of supercapacitors using single-walled carbon nanotube electrodes. The energy density was dependent on the cell-voltage cubed (up to 4 V: E = 1.43 × V³). The cubic relationship was attributed to the linear increase of the capacitance as a function of voltage, enabled by electrochemical doping. Furthermore, while up to 3.5 V, the maximum power rating of the nanotube electrodes increased as a function of the cell-voltage squared, beyond 3.5 V, a decline in power was observed as a result of depletion of the electrolyte's ions.     

Parallel Implementation of Successive Convex Relaxation Methods for Quadratic Optimization Problems

As computing resources continue to improve, global solutions for larger size quadrically constrained optimization problems become more achievable. In this paper, we focus on larger size problems and get accurate bounds for optimal values of such problems with the successive use of SDP relaxations on a parallel computing system called Ninf (Network-based Information Library for high performance computing).     

Measurement of the tau lepton mass and an upper limit on the mass difference between tau+ and tau-

The mass of the tau lepton has been measured in the decay mode tau-->3pinutau using a pseudomass technique. The result obtained from 414 fb-1 of data collected with the Belle detector is Mtau=[1776.61+/-0.13(stat)+/-0.35(sys)] MeV/c2. The upper limit on the relative mass difference between positive and negative tau leptons is |Mtau+-Mtau-|/Mtau<2.8 x 10-4 at 90% confidence level.     

Photo-switchable spin-crossover iron(III) compound based on intermolecular interactions

Iron(III) spin-crossover compounds, [Fe(qnal)₂]CF₃SO₃·MeOH (1·MeOH) and [Fe(qnal)₂]CF₃SO₃·acetone (1·acetone) were prepared and their spin transition properties were characterized by magnetic susceptibility measurement, Mössbauer spectroscopy and single crystal analysis. Two iron(III) compounds exhibited abrupt spin transition with thermal hysteresis loop (T _1/2?? = 115 K and T _1/2?? = 104 K for 1·MeOH, and T _1/2?? = 133 K and T _1/2?? = 130 K for 1·acetone). Single crystal analysis revealed both of the structures in high-spin (HS) and low-spin (LS) states for 1·acetone. The difference of bond length between the HS and LS states for 1·acetone was ~0.10 Å, which was corresponding to that of typical iron(III) SCO compounds. Specially, it showed strong intermolecular interactions by ???C?? stacking formed between the neighbor complexes leading to 2-D sheet. Both 1·MeOH and 1·acetone exhibited LIESST effect when it was illuminated at 1000 nm. We also confirmed that the introduction of strong intermolecular interactions, such as ???C?? stacking, can play an important role in LIESST effect.