Optical emission measurement of high-uniformity and high-density O2 supermagnetron plasma

The density and spatial distribution of O₂ supermagnetron plasma generated in between two parallel cathodes were measured by optical emission spectroscopy. Uniform plasma could be generated for the cathode spacing of 20–30 mm and a gas pressure of 2–10 mTorr on a magnetic field application of 130 G. The highest optical emission intensity (OEI) was observed at the cathode spacing of about 20 mm. OEIs of O-ions (464.9 nm) and O-radicals (777.1 nm) showed a strong RF-voltage-phase-difference dependencies of two supplied RF powers, and the OEIs at about 150°, i.e. around 180°, were about 2 times stronger than those of a conventional magnetron plasma generated at a gas pressure of 3–80 mTorr. In the spatial distribution measurements of OEIs, high-uniform plasmas were observed at a wide range of the RF phase difference, e.g. 0 and 120°.     

Angular magnetoresistance oscillations and magnetic breakdown in θ-(BEDT-TTF)2I3

We have conducted a systematic investigation of the angular dependent magnetoresistance oscillations (ADMRO) and Shubnikov-de Haas oscillations (SdH) in the quasi-two dimensional organic superconductor θ(BEDT-TTF)₂I₃. The Fermi surface derived from the AMDRO is found to correspond in size to the SdH oscillation orbit β, which is due to magnetic breakdown. The identification of this orbit highlights the sensitivity of the ADMRO. The ADMRO anisotropy is interpreted in terms of magnetic breakdown probability.     

Polymer-immobilized manganese(III)-Schiff base complexes for catalytic epoxidation of olefins

Polymer-linked manganese(III)-salen-type Schiff base complexes were prepared by the copolymerization of functionalized Schiff base, styrene, and divinylbenzene at various mixing ratios (1:10:0–1:12:4), followed by introduction of Mn(III) ion. The materials catalyzed epoxidation of cyclohexene with iodosylbenzene in CH₂Cl₂ as rapidly as the monomer complexes. The maximum total turnover reached 170, which is about 13 times higher than that of the monomer. The lifetime of polymer catalysts is discussed in terms of cross-linking and solvent effects.     

Uniaxial stress study of the magnetotransport properties of the quasi-two dimensional organic conductor α-(BEDT-TTF)2KHg(SCN)4

Measurements of the low temperature magnetoresistance of α-(BEDT-TTF)₂KHg(SCN)₄ under uniaxial stress perpendicular to the BEDT-TTF molecular layers indicate that the density wave ground state is suppressed by 1.5 Kbar. The fundamental Shubnikov-de Haas frequency decreases at an approximate rate of −20 tesla/Kbar and a slow, stress dependent oscillation appears for stresses above 0.9 Kbar. These enhanced stress effects are discussed in light of the high sensitivity of the Fermi surface to small changes in the crystal structure.     

Selective ion permeation through fluorocarbon polymer membrane

Hydrophobic polymers have rarely been used for membrane materials, but ions permeated selectively through a very thin hydrophobic membrane under a pressure gradient. The membrane was prepared by coating fluorocarbon polymer on a Teflon membrane filter. The permeabilities of strongly hydrated hydrophilic ions and hydrophobic ions are high through the membrane, but those of weakly hydrated ions are low. The selectivities were enlarged in the mixed salts solution of a low concentration at a high pressure. For example, the permeability of KCl was 0.077 and that of LiCl was 0.80 at 1 × 10^?4 mol/dm³ and 40 kg/cm². The coupling between volume flux and ion flux was high for strongly hydrated ions, while the diffusion flux derived by a concentration gradient was high for weakly hydrated ions.     

High-quality 1.3 ?m GaInAsP/InP BH-DFB lasers with first-order gratings

High-quality 1.3 ?m GaInAsP/InP BH-DFB lasers have been demonstrated. The threshold current was 16 mA and the differential quantum efficiency was 25% per facet. A stable single-longitudinal-mode oscillation was obtained, both up to four times the threshold current and up to 85°C. These results are comparable or superior to reported results of Fabry-Perot BH lasers.     

Analysis of TE/TM mode selectivity in DFB lasers with a phase-shift region

In phase-shift distributed feedback (DFB) lasers, there is limited suppression of the TM mode despite extremely large submode suppressibility. The TE/TM mode selectivity of a DFB laser structure with a nonuniform waveguide region as the phase shifter is analyzed. Calculations of the threshold gain difference between the TE and TM modes are performed using the effective index method and the coupled-wave theory. It is found that the TM mode suppressibility can be doubled by optimizing the dimensions of the phase-shift region. This structure overcomes the TM mode problem.<>     

Robotic range sensor with projection of bright ring pattern

A new type of optical range sensor is being proposed as a robotic sensor. The range sensor consists of the projection subsystem of an axially symmetrical light sheet and the detection subsystem for monitoring the focussing process of a lens. The projection subsystem produces a bright ring pattern through an objective lens on the surface of an object. Next, the distance from the range sensor to the surface of an object is calculated from the position of the lens. The prototype range sensor is able to measure the distance in the range of 430 to 570 mm with an accuracy of 0.3 mm. As the position of the objective lens is controlled so that the ring pattern projected on the surface of an object becomes a fine spot, the detection subsystem finds the position of the objective lens on which the output of photodiode comes to be maximum.