Silica-based 8×8 optical matrix switch module with hybridintegrated driving circuits and its system application

A compact, low-crosstalk 8×8 optical matrix switch module has been developed. A thermooptic switch chip and driving circuits with TTL interfaces are integrated on a 100-mm² ceramic substrate. It achieved a low insertion loss of 10.0 dB, a low crosstalk level of -25.9 dB, and had excellent stability in practical operation. A photonic intermodule connector for electronic switching systems in the near future is also demonstrated through the use of these optical switch modules     

Structure and Function of Retinochrome

Retinochrome is a photo-isomerase of all-trans-retinal to the 11-cis-isomer for rhodopsin synthesis. This protein is probably folded into seven α-helices spanning the membranes. Upon irradiation, it is converted to metaretinochrome, via pre-lumi- and lumiretinochrome, which are stable under 50 and 250 K, respectively. A series of analogue studies revealed that the cyclohexene ring and 6-s-cis-twisted conformation are important for binding. Modification of the 14-position suggests close location of the 14-H to the counterion.     

Bending loss reduction in silica-based waveguides by using lateraloffsets

The excess loss that occurs in waveguide bends can be minimized by offsetting the connecting waveguides so as to reduce the transition loss at the junctions. Such bends were investigated in detail by employing the beam propagation method (BPM) and it was found that they can be optimized with respect to overall loss. In the addition, the S-shaped waveguides and directional couplers with offset junctions were fabricated based on silica-based planar lightwave circuits (PLC) on silicon substrates. The measured insertion losses of these S-shaped waveguides and directional couplers, which are in good agreement with the calculated results, are the lowest thus far reported     

Mechanism of Dense Magnesia Layer Formation near the Surface of Magnesia-Carbon Brick

After operation of a basic oxygen furnace with a MgO-C brick lining, formation of a dense MgO layer is observed near the working surface. It is affected by soak atmosphere gas in the first stage of operation. As operation of the furnace proceeds, the MgO-C brick being submitted to cyclical heating and cooling, internal oxidation-reduction reactions of MgO and C occur. As a result, needlelike crystals of MgO grow at the interface between the dense MgO layer and the original layer, resulting in further growth of the densi MgO layer.     

Effect of crystalline properties on coercive force in iron acicular fine particles

Crystallographic properties and their size dependence in acicular fine particles of iron prepared by reduction from-FeOOH were investigated by transmission electron microscopy and compared with magnetic properties. Although both larger particles with an average needle length of 0.5m and smaller ones of 0.2m length have single domain configuration, the former are crystal lographicaIly polycrystalline while the latter are single crystal with a [100] axial orientation, an easy magnetization direction of iron. The coercive force, principally yielded by external shape anisotropy, is higher in smaller particles in spite of their inferior axial ratio. The intrinsic magnetocrystalline anisotropy is inferred to be the most responsible to give rise to this further increase of coercive force. The experimentally obtained values of magnetic properties are also compared with the theoretical estimation, which results semi-quantitatively in good accordance.     

Synthesis of hexagonal phases of WN and W2.25N3 by high‐pressure metathesis reaction

Hexagonal tungsten nitrides were synthesized by the metathesis reaction between WCl₆ and NaN₃ under high pressure and temperature. As well as tungsten mononitride (WN), which is isostructural with hexagonal tungsten carbide (WC), a nitrogen‐rich hexagonal compound was also confirmed in the product. The ratio of nitrogen to tungsten was determined to be 1.34 by the quantitative combustion method. The composition was estimated to be W_2.25N₃ by considering the crystal structure that is best explained by the X‐ray diffraction profile. Volume compression measurements under hydrostatic pressure revealed that the WC‐type WN has a higher bulk modulus (K₀ = 342 ± 1 GPa) than that of hexagonal W_2.25N₃ (K₀ = 291 ± 2 GPa).     

Direct observation of corrosion fatigue cracks in aluminum alloy using ultra-bright synchrotron radiation

Refraction contrast X-ray imaging using synchrotron source with ultra-bright light and highly directional beam is a unique method to diagnose non-destructively cracks or voids formed in materials, providing us in principle completely different information from conventional methods such as absorption contrast X-ray imaging. The authors have applied this imaging technique in SPring-8 to materials fracture study. We have also introduced home-made, in-situ observation facility system of crack formation and propagation in materials and the originally-designed 3D X-ray imaging systems to the experimental Hutch C of BL24XU (Hyogo BL) of SPring-8. Using these 3D X-ray imaging technique, in-situ observations of initiation and propagation of corrosion fatigue crack of Al-10%Mg alloy were conducted. The absorption contrast X-ray images were also obtained for comparison. It is concluded that the X-ray imaging method using ultra-bright synchrotron radiation is very useful for fracture research of materials and 3D X-ray contrast images are much more distinct than the conventional X-ray images to obtain information of the crack initiation and propagation behavior in the alloy.     

Addressing temporal inconsistency in indirect augmented reality

Multimedia Tools and Applications - Indirect augmented reality (IAR) employs a unique approach to achieve high-quality synthesis of the real world and the virtual world, unlike traditional...