Monolithically integrated 780-nm-band high-power and 650-nm-bandlaser diodes with real refractive index guided self-aligned structure

780-nm-band high-power and 650-nm-band laser diodes (LDs) with real refractive index guided self-aligned (RISA) structures are monolithically integrated for the first time. High-power and fundamental transverse mode operation at an output power of 100-mW continuous wave (CW) up to 80°C is attained for the 780-nm-band LD. For the 650-nm-band LD, high temperature and fundamental transverse mode operation at an output power of 10-mW CW up to 80°C is obtained     

Porous Titania Ceramic Prepared by Mimicking Silicified Wood

A porous titania ceramic with a woodlike microstructure that was analogous to silicified wood was prepared. The production of "titanified wood" was performed using the following process: (i) introduction of titanium tetraisopropoxide into wood materials via vacuum infiltration, (ii) hydrolysis of the titanium tetraisopropoxide in the cell structure to form a titania gel, and (iii) firing at a temperature of 600°–1400°C in air. The resulting titania ceramic had the same external and internal forms of the original wood.     

Quasi-velocity-matched LiTaO3 guided-wave optical phasemodulator for integrated ultrashort optical pulse generators

A quasi-velocity-matched guided-wave optical phase modulator using periodically domain inverted LiTaO₃ is fabricated and demonstrated for the first time to the best of the authors' knowledge. Band modulation characteristics and the generation of optical side-bands of ~100 GHz are confirmed successfully. This modulator can be used to construct an integrated ultrashort optical pulse generator     

Computer Simulation of Axis-Encircling Beams Generated by an Electron Gun with a Permanent Magnet System

Results from computer aided design of a novel electron gun generating axis-encircling beams are presented and discussed. Numerical experiments were performed by the new version of the software package GUN-MIG named GUN-MIG/CUSP. It is based on a self-consistent relativistic model and is developed as a problem oriented tool for analysis of electron-optical systems with magnetron injection guns (MIG) and electron guns with field reversal (cusp guns), forming axis-encircling beams. As a result of the simulations an electron-optical design of a novel electron gun with permanent magnet system was accomplished. The gun is expected to form high quality beams with small velocity spread and beam ripple. Parameters of the generated beams are appropriate for a prospective weakly relativistic high harmonic large orbit gyrotron (LOG). The development of such device is in progress now at the Research Center for Development of Far-Infrared Region (FIR Center) at Fukui University.     

Multipoint cure monitoring of CFRP laminates using a flexible matrix sensor

Since a carbon fiber reinforced plastic (CFRP) structure is complicated in the adoption of integral molding, local molding faults such as under curing and dry spots are liable to occur. To solve this problem, the distribution of the degree of curing for the entire composite structure must be measured. In the present study, we propose a patch-type flexible matrix sensor based on permittivity measurements. Multiple electrodes and wirings are readily fabricated simultaneously using a photolithographic process. Moreover, the sensor has only m + n wirings for m × n sensors, and is thereby suitable for multipoint cure monitoring. We also constructed a method for estimating the degree of curing considering the effect of frequency dependence of the permittivity of resin and viscosity variation due to temperature change. Experiments of multipoint cure monitoring are carried out using a CFRP plate and an actual aircraft structure. As a result, we confirmed the effectiveness of this method by comparing with results using a conventional differential scanning calorimeter.     

Simultaneous determination of intraparticle diffusivity and liquid film mass transfer coefficient from a single-component adsorption uptake curve

In general, the rate of adsorption involves both rates of liquid film mass transfer and intraparticle diffusion. Many researchers tried to minimize the effect of liquid film resistance when determining the effective intraparticle diffusivity. However, in some cases (for example, small adsorbent particle size), the liquid film resistance may not be easily eliminated in a fixed bed process. Therefore, this research proposed using the shallow bed technique to determine both intraparticle diffusivity (D(S)) and liquid film mass transfer coefficient (k(F)) simultaneously from a single-component adsorption uptake curve (AUC). The task was accomplished by the determination of the Biot number (Bi) from experimental adsorption uptake curve (EAUC). The Bi represents the ratio of the rate of transport across the liquid film to the rate of intraparticle mass transfer. The detailed calculation method is addressed in this paper. The method proposed in this research can be applied in the range of Bi between 0.5 and 200 where both liquid film resistance and intraparticle diffusion are significant.     

Influence of Diffused Boron Into MgO Barrier on Pinhole Creation in CoFeB/MgO/CoFeB Magnetic Tunnel Junctions

A relationship between boron (B) diffusion into the MgO barrier and pinhole creation in CoFeB/MgO/CoFeB-magnetic tunnel junctions (MTJs) was investigated. The diffused B in the MgO layer was identified by secondary ion mass spectrometry for the MTJs annealed at 350degC , which provide the giant magnetoresistance (TMR) ratio. The pinhole density, estimated from the statistic distribution of breakdown voltage of the TMR properties, increased as either the thickness or the B content of the CoFeB layer became thicker or higher. These experimental findings imply that the diffused B into the MgO barrier creates pinholes to short-circuit the tunnel conduction, since the amount of diffused B into the MgO barrier might be related to the total amount of the B content in the CoFeB layer. Three different techniques were found to be useful for the reduction of diffused B into the MgO barrier layer; usage of materials having boron affinity for capping layer, decrease of the total amount of B-content in CoFeB layer, and reduction of grain boundaries in the MgO barrier layer.     

The structures and gas-sorption properties of l-tyrosine films prepared by the Knudsen effusion method

l-tyrosine (L-Tyr) films with an oblique columnar structure were prepared by the Knudsen cell effusion method. The L-Tyr films were formed at a Knudsen cell temperature that was sufficiently lower than the decomposition temperature of L-Tyr. As the heating rate controlled by DC current is increased, the molecular network constructed of hydrogen bonds tends to collapse, and the film density and surface hydrophobicity tend to decrease. Higher DC currents are likely to induce a decarboxylation reaction. L-Tyr films prepared at a higher heating rate have enhanced gas sorption capabilities for a wide range of volatile organic compounds (VOCs). The sorption capabilities are particularly enhanced for linear hydrocarbons. The gas sorption characteristics for VOCs suggest that the adsorption in the vicinity of the film surface is dominant rather than diffusion into the film, which corresponds with the densified surface morphology.     

A creep life assessment method for boiler pipes using small punch creep test

The small punch creep (SPC) test is considered as a highly useful method for creep life assessment for high temperature plant components. SPC uses miniature-sized specimens and does not cause any serious sampling damages, and its assessment accuracy is at a high level. However, in applying the SPC test to the residual creep life assessment of the boiler in service, there are some issues to be studied. In order to apply SPC test to the residual creep life assessment of the 2.25Cr–1Mo steel boiler pipe, the relationship between uniaxial creep stress and the SPC test load has been studied.     

All solid-state sheet battery using lithium inorganic solid electrolyte, thio-LISICON

All solid-state sheet lithium battery was developed using inorganic solid electrolyte, thio-LISICON (Li_3.25Ge_0.25P_0.75S₄), Li–Al anode, and Mo₆S₈ cathode materials, and the sheet manufacturing process was established. The new sheet-configuration was consisted of the cathode with the grid of current collector, electrolyte sheet with or without mechanical support, and aluminum/lithium composite sheet anode. A sheet battery with a dimension of 30 mm × 30 mm showed good charge–discharge characteristics without any capacity fading at a current of 0.1 mA.