Observation of B0-->pi0pi0

We report the observation of the decay B0-->pi(0)pi(0), using a 253 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) collider. The measured branching fraction is B(B0-->pi(0)pi(0))=(2.3(+0.4+0.2)(-0.5-0.3))x10(-6), with a significance of 5.8 standard deviations including systematic uncertainties. We also make a measurement of the direct CP violating asymmetry in this mode.     

Novel efficient routes to heparin monosaccharides and disaccharides achieved via regio- and stereoselective glycosidation

A new methodology for the synthesis of heparin building blocks has been developed. We describe novel efficient routes to both L-iduronic acid and D-glucuronic acid acceptors. Glycosylation with thioglycosides donors gave corresponding disaccharides in a regio- and stereoselective fashion. An improved approach to synthesizing azido-glucose thioglycoside donor to render azido-sugar from mannose via nucleophilic substitution is described. [reaction: see text]     

Rationality, regularity, and -cofiniteness

We demonstrate that, for vertex operator algebras of CFT type, -cofiniteness and rationality is equivalent to regularity. For -cofinite vertex operator algebras, we show that irreducible weak modules are ordinary modules and -cofinite, is -cofinite, and the fusion rules are finite.

     

Competing orders and disorder-induced insulator to metal transition in manganites

Effects of disorder on the two competing phases, i.e., the ferromagnetic metal and the commensurate charge/lattice ordered insulator, are studied by Monte Carlo simulation. The disorder suppresses the charge/lattice ordering more strongly than the ferromagnetic order, driving the commensurate insulator to the ferromagnetic metal near the phase boundary in the pure case. Above the ferromagnetic transition temperature, on the contrary, the disorder makes the system more insulating, which might cause an enhanced colossal magnetoresistance as observed in the half-doped or Cr-substituted manganites. No indication of the percolation or the cluster formation is found, and there remains the charge/lattice fluctuations instead which are enhanced toward the transition temperature.     

Nearest-neighbor configuration in (GaIn)(NAs) probed by x-ray absorption spectroscopy

Ga(1-x)In(x)N(y)As(1-y) is a promising material system for the fabrication of inexpensive "last-mile" optoelectronic components. However, details of its atomic arrangement and the relationship to observed optical properties is not fully known. Particularly, a blueshift of emission wavelength is observed after annealing. In this work, we use x-ray absorption fine structure to study the chemical environment around N atoms in the material before and after annealing. We find that as-grown molecular beam epitaxy material consists of a nearly random distribution of atoms, while postannealed material shows segregation of In toward N. Ab initio simulations show that this short-range ordering creates a more thermodynamically stable alloy and is responsible for blueshifting the emission.     

Synthesis of (--)-Muricatacin via alpha- and alpha'-C-H bond functionalization of tetrahydrofuran

(--)-Muricatacin, a potent cytotoxic (4R,5R)-5-hydroxyheptadecan-4-olide, has been synthesized through alpha-C--H hydroxyalkylation and alpha'-C--H oxidation of tetrahydrofuran. This study presents a novel method for C--H bond functionalization as a means for preparing gamma-(hydroxyalkyl)-gamma-butyrolactones.     

Electrolytic synthesis of ammonia in molten salts under atmospheric pressure

Ammonia was successfully synthesized by using a new electrochemical reaction with high current efficiency at atmospheric pressure and at lower temperatures than the Haber-Bosch process. In this method, nitride ion (N3-), which is produced by the reduction from nitrogen gas at the cathode, is anodically oxidized and reacts with hydrogen to produce ammonia at the anode.     

Spinodal decomposition of two-dimensional fluid mixtures: A spectral analysis of droplet growth

The spinodal decomposition of two-dimensional fluid mixture is studied by numerical simulation. For the high viscous fluid mixture it has not been evident whether the interfacial tension is relevant to the droplet growth or not. A length scale R defined by the structure function extracting the effect of the long wavelength mode justifies a rapid growth close to R approximately t, but the length scale energetically defined reveals a much slower growth R approximately t(0.5), where t is time. This discrepancy represents the violation of the dynamical scaling with single length scale. The slow gowth of the length scale is attributed to the accumulation of the number of isolated droplets in phase separating state, whereas the rapid growth represents the relevance of the surface tension as the driving force in two dimensions. For a low viscous fluid mixture the dynamical scaling is a good assumption with the growth law R approximately t(2/3) up to a very large Reynolds number Re approximately 1500, which is the limit in the present simulation.     

Two types of diffusions at the cathode/electrolyte interface in IT-SOFCs

Analytical transmission electron microscopy, in particular with the combination of energy dispersive X-ray spectroscopy (EDX) and electron energy-loss spectroscopy (EELS), has been performed to investigate the microstructure and microchemistry of the interfacial region between the cathode (La_0.6Sr_0.4Co_0.8Fe_0.2O₃, LSCF) and the electrolyte (Gd-doped ceria, GDC). Two types of diffusions, mutual diffusion between cathode and electrolyte as well as the diffusion along grain boundaries, have been clarified. These diffusions suggest that the chemical stability of LSCF and GDC are not as good as previously reported. The results are more noteworthy if we take into consideration the fact that such interdiffusions occur even during the sintering process of cell preparation.