Re-evaluation and reconstruction of water purification system using soil. I. Assessment of soil as a sorbent of humic substances and phosphate ion.

The purpose of our study is to develop a treatment procedure for humic substances (HS hereafter) and phosphate ion in wastewater and environmental water by percolation of the water through a constructed soil layer at the hydraulic loading of a few metres per day. In the present work, batch sorption tests were conducted for more than 80 samples of soil, sludge, mineral and organic materials in order to find good sorbents for fulvic acid (FA hereafter) and phosphate ion. The results showed that the sorption of FA was high for some charcoal, and apatite and goethite minerals. Comparatively high sorption of FA was found for some Andosols and volcanic ash soil. Significant sorption of phosphate ion, on the other hand, was found for various types of soil, sludge from water treatment plants and some waste materials. The linear isotherm was obtained for the sorption of FA to a charcoal, apatite and goethite minerals, and Andosols.     

A brushless self-exciting three-phase synchronous generatorutilizing the 5th-space harmonic component of magneto motive forcethrough armature currents

A novel brushless self-exciting three-phase synchronous generator is proposed. It consists of three-phase armature windings on the stator, one field winding and one exciting winding with five times as many poles as that of the armature winding on the rotor, and a three-phase reactor connected to the terminal of the armature windings. By utilizing the 5th-space harmonic component of armature electromotive force, small voltage regulation for various loads and no oscillatory tension occurring at the rotor shaft were realized. The basic constitution, principle of operations, and exciting characteristics are described. The experimental results obtained from using a trial generator demonstrated its practical usefulness     

Optical study on opaline thin films grown by vertical deposition

We have studied optical properties of opaline thin films grown by the vertical deposition method. The opaline films under study were three-dimensional close-packed arrangements of a-SiO₂ spheres. The fcc domains, which are of 10–50 μm in size and separated by cracks, were seen in FE-SEM images. Analysis of angle-resolved transmissivity of opaline films shows that they act as three-dimensional photonic crystals. Photonic stop-bands were observed and attributed to the {111} family of crystallographic planes. Crystallographic structure of the films was characterized as twinned fcc, in which twins are spatially separated by cracks.     

Optical study on opaline thin films grown by vertical deposition

We have studied optical properties of opaline thin films grown by the vertical deposition method. The opaline films under study were three-dimensional close-packed arrangements of a-SiO₂ spheres. The fcc domains, which are of 10–50 μm in size and separated by cracks, were seen in FE-SEM images. Analysis of angle-resolved transmissivity of opaline films shows that they act as three-dimensional photonic crystals. Photonic stop-bands were observed and attributed to the {111} family of crystallographic planes. Crystallographic structure of the films was characterized as twinned fcc, in which twins are spatially separated by cracks.     

InGaAsP/InP buried crescent laser diode emitting at 1.3 µm wavelength

The fabrication procedure, designing of an active region and a p-n-p-n current blocking structure, characteristics and the aging results of an InGaAsP/InP buried crescent (BC) laser diode are described. The BC laser diodes exhibit high laser performances, such as a low-threshold current, a fundamental transverse mode oscillation with linear light output-current characteristics. CW operation at as high as 100°C is achieved with a junction up configuration as a result of the improvement in the current blocking structure. A stable CW operation at 80°C has been realized with a constant optical output power of 5 mW.     

Low-energy x-ray interaction coefficients: Photoabsorption,scattering, and reflection: E = 100–2000 eV Z = 1–94

The primary low-energy x-ray interactions within matter are photoabsorption and coherent scattering, which can be efficiently described for photon energies outside the threshold regions by using atomic scattering factors. These may be uniquely determined through quantum dispersion relations from photoabsorption data. With the available fittings of the photoabsorption cross sections and with a new compilation of such data for the region 30–300 eV, continuous sets of the photoabsorption cross sections from 30 to 10 000 eV have been determined for 94 elements. With these, for the region 100–2000 eV, atomic scattering factors which are independent of scattering angle and which include the relatively strong anomalous dispersion structures have been obtained. Methods are reviewed and currently important examples of the application of atomic scattering factors to the detailed characterization of selected x-ray mirror monochromators and of Bragg multilayer and crystal analyzers for low-energy x-ray analysis are presented.     

Highly Efficient 68-W Green-Beam Generation by Use of an Intracavity Frequency-Doubled Diode Side-Pumped Q-Switched Nd:YAG Rod Laser

An intracavity frequency-doubled diode side-pumped Nd:YAG laser was developed by use of an advanced cavity configuration and a diffusive close-coupled side-pumping design. A maximum green power of 68 W was generated at a 20-kHz repetition rate with 18.4% optical-to-optical conversion efficiency and 7.1% electrical-to-optical conversion efficiency.     

Preparation of high-temperature filter by pressure-pulsed chemical vapour infiltration of SiC into carbonized paper-fibre preforms

SiC was partially infiltrated into three types of carbonized paper-fibre preforms using pressure-pulsed chemical vapour infiltration from SiCl4(4%)–CH4(4%)–H2 at 1100 °C (A-type preforms, source fibres of filter paper; BH- and BL-type preforms, source fibres of recycled paper). The porosity of the preforms decreased linearly with the number of pulses. After 10 000 pulses, the porosity of A-, BH- and BL-type samples was 77,78 and 85%, respectively. Average pore sizes of A-, BH- and BL-type samples after 10 000 pulses were about 5.0, 2.7 and 7.0 m, respectively. On an A-type sample of 10 mm and 5 mm long after 10 000 pulses, pressure drop along the direction of axial air flow was 10 kPa at a face velocity of 0.8 m s–1. The order of pressure drop was BH,>, A >, BL. Flexural strength of A-type sample reached 10 MPa after 15,000 pulses.