Thickness uniformity of HDPE blown film: Relation to rheological properties and density

Previous work has elucidated that the wall slip velocity and viscosity of polymer melts influence the thickness uniformity of blown film. The present study investigates the effects of the stress dependence of wall slip, the shear thinning and the density on the uniformity. We have prepared high‐density polyethylenes with a variety of molecular weight distributions, which have different rheological properties. Examination of the thickness uniformity of their blown film has shown that the uniformity is correlated with wall slip velocity, the stress dependence of the velocity, melt viscosity, shear thinning and density; the coefficient of the correlation is determined to be 0.990. The reason why the stress dependence of wall slip and the shear thinning affect the uniformity is explained in terms of polymer melt flow behavior in a die, while the effect of density is interpreted considering bubble fluctuation in the blow‐up process. Polym. Eng. Sci. 44:965–972, 2004. © 2004 Society of Plastics Engineers.     

Subboundaries in hcp4He crystals studied by SR X-ray topography

The internal structure of hcp⁴He crystals was studied by SR (synchrotron radiation) X-ray topography. Subboundaries in the crystals appeared as black or white bands in the X-ray topographs. In one of the hcp⁴He crystals, the subboundaries turned out to be flat planes perpendicular to the basal plane. They were small-angle tilt boundaries which consisted of basal edge dislocations. The dislocation spacing in one of the subboundaries was determined to be 800 nm and the total density of the boundary dislocations to be 2.6 × 10⁵ cm^–2. The subboundaries in another hcp⁴He crystal were curved and/or branching, indicating that the crystal was strained.     

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.