Simultaneous amplification of wavelength-division-multiplexed signals by a highly efficient fibre Raman amplifier pumped by high-power semiconductor lasers

We describe the first operation of a high-power semiconductor-laser pumped fibre Raman amplifier (FRA) using high-Raman-gain optical fibre in the 1.5?m region. A high optical gain of 5 dB for 60mW of pump power is obtained. We have also achieved simultaneous amplification of wavelength-division-multiplexed signals by the FRA.     

Femoral condyle geometry in the normal and varus knee

Femoral condyle geometry was evaluated in 30 normal and 30 varus knees using magnetic resonance imaging. In the sagittal view, the distal part of the medial condyle was deformed in the varus knees, but there was no significant difference in the posterior part of the medial condyle between the normal and varus knees. In the transverse view, the transepicondylar axis (a reliable rotational landmark) showed approximately 6 degrees external rotation relative to the posterior condylar axis in the varus knees and the normal knees. The results of this study suggest that no hypoplasia exists at the posterior part of the medial condyle in varus knees. In addition, the posterior condylar axis may be a reliable rotational landmark but is in relative internal rotation in varus knees when total knee arthroplasty is performed.     

Mobile robot with transformable crawler and intelligent guidance

Recently, great advances have been made in intelligent mobile robot technology, advances which will provide autonomous travelling ability to robots, allowing them to surmount stairs and other obstacles. In this paper, we present an active adaptive crawler mechanism and a visual navigating system, developed to achieve practical speed for industrial use of the mobile robot. By using a crawler-type mechanism, the active adaptive suspension mechanism maintains vehicle stability and achieves good climbing capability without increasing weight. Further, we have developed technology for an intelligent navigating mechanism, to guide the robot as it passes through a building. Once the robot is provided with an inner layout plan of the respective building, it can achieve practical mobile speed for industrial use.     

Near-infrared combination and overtone bands of CH in CHX3, CHX(2)-CHX2, and CHX(2)-CX(2)-CHX2

In the present report we studied spectral characteristics of the near-infrared combination and overtone bands of CH vibrations of a CH sequence. The near-infrared bands of the CH in CHX3 (X, halogen), which were interpreted in terms of the CH stretching and CH deformation fundamentals without any ambiguity, typically showed how the frequency and intensity of a combination or an overtone depend on the vibrational excited state. In the CH-C-CH of CHX2CX2CHX2, the vibrations of one CH are isolated from those of the other CH, and the combination and overtone bands were similarly interpreted as those of the CH, although each of the combination bands was split into two because of non-degeneracy of the CH deformation. In the CH-CH of CHX2CHX2, the CH deformations only have coupled modes. The first combination showed four narrowly separate bands, which were reasonably interpreted on the basis of the CH stretching and the coupled CH deformation modes. We demonstrated that the first combination of coupled modes as well as the combination of up to, at least, the third order of isolated modes have the nature of the characteristic bands.     

Inorganic-organic hybrid molecular architectures of cyanometalate host and organic guest systems: specific behavior of the guests

Molecular architectures built of inorganic cyanometalate building blocks provide variegated host structures with several organic guest molecules. The strategies to derive novel structures are presented briefly. The formation of a charge-transfer (CT) complex as the guest inside the cavity and the photochemistry of the CT complexes are discussed. The chemical pressure that the guest experiences inside the cavity is also discussed based on the vibrational spectroscopic results.     

Preparation and gas permeability of polymer blend membranes of polystyrene and poly[1,1,1-tris(trimethylsiloxy)methacrylate propylsilane]

The gas permeability of O₂ and CO₂ was sutidied for various polymer blend membranes of polystyrene (PSt) and poly[1,1,1-tris(trimethylsiloxy)methacrylate propylsilane (PTMPS). In order to improve the compatibility of these polymer blends, the effect of addition of the graft copolymer was also investigated. The gas permeability of various composition polymer-blend membranes increases rapidly with an increasing content of PTMPS in the polymer blend. In the polymer blend membranes containing the graft copolymer, the gas permeability decreases with an increase in the graft copolymer content and then reaches a nearly constant value, when the PTMPS content remains constant. This result is attributed to a decrease in interstices at phase boundaries, owing to improvement in compatibility of the component polymers. This method of membrane preparation is very useful for making membranes with required properties.