Optical cascade star network--A new configuration for a passive distribution system with optical collision detection capability

A new fiber-optic passive network configuration with novel star couplers is reported. The new optical network configuration, an Optical Cascade Star Network, optimizes contradictory requirements for network system size and cable cost, and matches the actual layout in offices or factories. The star coupler is novel in that the optical signal does not return to the source terminals. This feature enables cascade connection of star networks, the use of simple repeaters for system extension, and the easy support of carrier sense multiple access with collision detection (CSMA/CD) bus access procedure. Experimental results obtained from novel star couplers, optical transceivers with (CSMA/CD) bus compatibility, and a total network system are also discussed.     

Polarized target asymmetry in π° photoproduction between 0.4 and 1.0 GeV around 100°

The polarized target asymmetry in the reaction γp→π°p has been measured at c.m. angles around 100° for photon energies between 0.4 and 1.0 GeV by detecting both the recoil proton and the π°. The result is compared with recent analyses.     

Spectral width of saturated absorption spectra of Cs with a laser diode

The saturated absorption spectra and line widths of the Cs-D2line were observed as a function of the incident power. A minimum spectral width of 20 MHz was obtained when the incident power was under 0.1 mW and all of the hyperfine spectral lines and the cross-over resonance lines were resolved.     

Small loss-deviation tapered fibre star coupler with mixer rod

A large-scale biconical tapered fibre star coupler with mixer rod was developed. It shows considerable improvement in regard to power distribution uniformity. The loss deviation and average excess loss for a 100 × 100 star coupler were 0.37 and 3.2 dB, respectively.     

Liquid phase hydrogenation of naphthalene in the presence of CO over supported Ni catalyst

The liquid phase hydrogenation of naphthalene was performed in the presence of CO over a commercial Ni/SiO₂-Al₂O₃ catalyst. Naphthalene was hydrogenated even in the presence of CO at elevated temperatures, accompanying the hydrogenation of CO. Two activation energy values were obtained for the naphthalene hydrogenation depending on the reaction temperature. FT-IR measurement of the adsorbed CO was also carried out. Hydrogenation of the adsorbed CO created sites active for naphthalene hydrogenation.     

Donnan potential and surface potential of a spherical soft particle in an electrolyte solution

A simple numerical method, which does not involve numerical integration of the Poisson-Boltzmann equations, is presented for obtaining the relationship between the Donnan potential and surface potential of a spherical soft particle (i.e., a polyelectrolyte-coated particle) in a symmetrical electrolyte solution. We assume that a soft particle consists of the particle core of radius a covered with an ion-penetrable surface layer of polyelectrolytes of thickness d and that ionized groups of valence Z are distributed at a uniform density of N in the polyelectrolyte layer and the relative permittivity takes the same value in the regions outside and inside the polyelectrolyte layer. The Donnan potential and surface potential are determined by the values of a, d, Z, N, and the Debye-Hückel parameter kappa of the electrolyte solution. Numerical results obtained by the present method are in excellent agreement with exact results obtained by solving the nonlinear spherical Poisson-Boltzmann equations for the both regions inside and outside the polyelectrolyte layer.     

Transesterification of various methyl esters under mild conditions catalyzed by tetranuclear zinc cluster

A new catalytic transesterification promoted by a tetranuclear zinc cluster was developed. The mild reaction conditions enabled the reactions of various functionalized substrates to proceed in good to high yield. A large-scale reaction under solvent-free conditions proceeded with a low E-factor value (0.66), indicating the high environmental and economical advantage of the present catalysis.     

Periodic porous stripe patterning in a polymer blend film induced by phase separation during spin-casting

A periodic striping pattern with microscale pore size is observed on the surface of thin films prepared by spin-casting from a polystyrene (PS) and polyethylene glycol (PEG) blend solution. The pattern is created by the convection generated by thermal gradients in the solution between the substrate and film solution during solvent evaporation, the radial flow of the spin-coated solution, and the primary and secondary phase separation of the PS and PEG solutions. The formation mechanism of the periodic porous stripe pattern is discussed, wherein the effects of the polymer blend weight ratio, polymer concentration, and drying rate on the formation of the periodic porous striping pattern are investigated using scanning electron and atomic force microscopy.     

Effect of core charge density on the electrophoresis of a soft particle coated with polyelectrolyte layer

The electrophoresis of a charged soft particle with charged rigid core is considered under a weak imposed field condition. The rigid core of the soft particle is considered to have a finite dielectric permittivity and a fixed volume charge density. The electric potential distribution is determined by solving the Poisson-Boltzman equation out side the rigid core and a Poisson equation within the core along with continuity conditions on the core-shell interface. We have extended the analytic expression of Ohshima (Electrophoresis 27:526–533, 2006) for the electrophoretic mobility of a soft particle with a charged shell to include the effect of the volume charge density of the rigid core. Mobility based on the present expression matches exactly with the existing analytical solutions for a soft particle with an uncharged core. We have also made a comparison of our solution for mobility with an uncharged rigid core with the existing experimental results. The impact of the core charge density on the soft particle mobility is analyzed.