Quark mixings in a subquark model

Quark mixings and theor momentum dependences are discussed in a subquark model in which the weak current is made of the iso-doublet spinor subquarks. The Cabibbo angle is predicted to become larger as momentum transfer between quarks grows up.     

Time-resolved optical transmission during pulsed-laser annealing of ion-implanted amorphous silicon-on-sapphire

Time-resolved optical transmission of annealing dye laser pulse (wavelength : 590 nm and pulse width : 250 nsec) itself has been measured in thin layers of Si⁺-implanted amorphized silicon-on-sapphire (SOS) with several energy densities in the range of 0.02 to 2.64 J/cm². At the energy densities where the amorphized SOS is recrystallized, the transmission exhibits a sudden drop and subsequently remains at a detectable level. This laser-induced absorption is inconsistent with the presence of ordinary molten silicon but suggests an electronic structural-change from amorphous to crystalline state.     

Single-electron-capture cross sections for 0.4–5.0 keV He+ ions incident on alkali-vapor targets

Total cross sections for single-electron capture by He⁺ ions in vapor targets of Cs, Rb, K and Na have been determined in the energy range 0.4–5.0 keV. The energy dependence of the cross-section curves is very similar for all the targets. The cross sections for all the targets are maximum at about the same energy, 1.5 keV. Comparison is made with other reported experimental and theoretical results.     

The regioselective alkylation of 4,6-dimethyl-1-phenyl-2(1H)-pyrimidinone

4,6-Dimethyl-1-phenyl-2(1H)-pyrimidinone (I) was treated with alkyl halides in the presence of sodium hydride at low temperature to afford only C-6 alkylated products III and IV in good yields. Further, the mono-, IIIa-d, and di-alkylated 2(1H)-pyrimidinones IVa-d were selectively obtained by changing the amount of alkyl halides.     

Spallation of niobium by 12 GeV protons

Cross sections for the production of approximately 50 radionuclides in the interaction of niobium with 12 GeV protons were determined by the activation technique. The results were parametrized in terms of a 6-parameter equation which reproduced the measured charge-dispersion and mass-yield curves.     

Caesium-selective PVC membrane electrodes based on bis(crown ether)s

Caesium-selective PVC membrane electrodes based on bis(crown ether)s containing benzo-18-crown-6 moieties were prepared using two kinds of plasticizers. Selectivity coefficients for various interfering monovalent ions were determined by the mixed solution method, and were found to relfect the complexing property and extractability of the bis-(benzo-18-crown-6)s. The electrochemical selectivity was also compared with that of the corresponding monocyclic analog and valinomycin.     

Remaining noise-induced spatiotemporal dynamics in a free electron laser stabilized by feedback control

We investigate the efficiency of the pulsed regime stabilization by feedback control in a free electron laser (FEL) in oscillator configuration. We show that a hidden dynamics remains in the controlled FEL. Though not visible in the evolution of the pulse envelope, this dynamics affects the internal pulse shape evolution, and thus the FEL spectrum and coherence properties. The experimental results obtained on the UVSOR FEL are interpreted in the framework of a field master equation model. The stochastic nature of spontaneous emission is taken into account, and appears as an essential ingredient since the dynamics of the controlled structures is governed by noise like the other stable regimes of the FEL.     

A steep one-step [HS-HS] to [LS-LS] spin transition in a 4,4'-bipyridine linked one-dimensional coordination polymer constructed from a pyrazolato bridged Fe(II) dimer

The variable temperature magnetic susceptibility, X-ray crystallography, and M?ssbauer and Raman spectra of a new dinuclear complex-based one-dimensional coordination polymer [[Fe(II)2(NCS)2(mu-bpypz)2](micro-4,4'-bpy)].MeOH demonstrated a steep one-step [HS-HS] to [LS-LS] spin transition.