A full‐color eyewear display using planar waveguides with reflection volume holograms

Abstract— A full‐color eyewear display with over 85% see‐through transmittance with a 16° horizontal field of view was developed. Very low color crosstalk, less than 0.008 Δu′v′ uniformity, and 120% NTSC color gamut were achieved. Waveguides with two in‐ and out‐coupling reflection volume hologram elements enabled a simple configuration that has an optical engine beside the user's temples. The reflection volume hologram elements used on the waveguides realized a small thickness of 1.4 mm for each waveguide, and an out‐coupling reflection volume hologram used as an optical combiner contributed a high see‐through transmittance of 85% due to its wavelength selectivity. However, there are technical challenges in achieving a reasonable screen size and quality color images with optics that utilize holographic waveguides because holograms have large chromatic dispersions compared to conventional optical elements such as lenses and mirrors. Approaches to overcome these issues are described.     

Technique for anisotropic extension of organic crystals: application to temperature dependence of electrical resistance

We have developed a technique for the anisotropic extension of fragile molecular crystals. The pressure medium and the instrument, which extends the pressure medium, are both made from epoxy resin. Since the thermal contraction of our instrument is identical to that of the pressure medium, the strain applied to the pressure medium has no temperature dependence down to 2 K. Therefore, the degree of extension applied to the single crystal at low temperatures is uniquely determined from the degree of extension in the pressure medium and thermal contractions of the epoxy resin and the single crystal at ambient pressure. Using this novel instrument, we have measured the temperature dependence of the electrical resistance of metallic, superconducting, and insulating materials. The experimental results are discussed from the viewpoint of the extension (compression) of the lattice constants along the parallel (perpendicular) direction.     

Thermodynamic study and intrinsic type II superconductivity in the A-15 compound V3Si

The specific heat of a single crystal of the A-15-type compound V₃Si in the normal, mixed, and superconducting states has been measured from 4 to 30 K in magnetic fields up to 50 kOe. The analysis has been performed in a self-consistent way based on the second-order phase transition from the normal to the superconducting state. The thermodynamic critical field and then various physical parameters characterizing the superconducting and normal states are almost consistently derived from the thermodynamics and the microscopic BCS-GLAG theory. It is confirmed that V₃Si is an intrinsic type II superconductor with a high intrinsic GL parameter ₀.This work was partially supported by a Grant in Aid for Scientific Research (B) from the Ministry of Education.     

Determination of seventeen pesticide residues in agricultural products by LC/MS

Residues of 17 pesticides in agricultural products were determined by LC/MS with an atmospheric pressure chemical ionization (APCI) interface in both positive and negative ion modes. Pesticides were extracted with acetonitrile, and the extracts were cleaned-up with a primary and secondary amine (PSA) mini-column eluted with acetone-hexane (1:1). Rice, orange and potato were spiked with the 17 pesticides at 0.1 microgram/g and analyzed by the proposed method. The average recoveries of these pesticides usually ranged from 70 to 98% and the relative standard deviations were usually around 10%. These results suggested that LC/MS with APCI could be used to determine the residue levels of the 17 pesticides in these crops.     

A relation between edit distance for ordered trees and edit distance for Euler strings

We consider a relationship between the unit cost edit distance for two rooted ordered trees and the unit cost edit distance for the corresponding Euler strings. We show that the edit distance between trees is at least half of the edit distance between the Euler strings and is at most 2h+1 times the edit distance between the Euler strings, where h is the minimum height of two trees. The result can be extended for more general cost functions.     

Polybrominated diphenyl ether flame retardants in foodstuffs and human milk

Polybrominated diphenyl ethers (PBDEs) have been used worldwide as additive flame retardants in polymeric materials. Commercial products consist predominantly of deca-, octa-, and pentabromodiphenyl ether mixtures. PBDEs are resistant to degradation in the natural environment and Penta-BDE in particular accumulates in the fatty tissues of fish, birds and mammals (including humans). Several toxic effects on the thyroid system or on neurodevelopment have been reported in experimental animals exposed to PBDEs. It is likely that human exposure is predominantly through the ingestion of contaminated food and/or mother's milk. The potential health effects of dietary exposure to PBDEs have now become a great concern because of the increasing PBDE levels in the biosphere. In this review, published information on the toxicology of PBDEs, levels in foodstuffs and human milk, and analytical methods has been compiled.     

Calculations of heats of formation for nitroaromatics with PM3 and MM2

Abstract

We have attempted to calculate heats of formation (Δ H _f °) for various aromatic nitro compounds with the semi-empirical molecular orbital theory and the molecular mechanics. As the results we may say that PM3, a semi-empirical MO method, and MM2, molecular mechanics, can estimate Δ H _f ° of energetic materials with accuracy enough to use Δ H_f° for energy hazards prediction. In case of aromatic polynitro compounds, both methods may be able to calculate accurate Δ H_f°.     

Effect of impurity on dissolution behavior of simulated molybdenum cermet fuels

The effects of impurity Zr on dissolution behavior into nitric acid of sintered Mo pellets were investigated using simulated fuels to accumulate basic data and knowledge concerning the matrix of Mo-cermet fuels. Mo pellets containing 1– 10 mol% Zr were prepared by conventional powder metallurgical route. After characterization tests using optical microscopy (OM), X-ray diffraction and secondary electron microscopy-energy dispersive X-ray spectrometry (EDX), the sintered pellets were subjected to dissolution tests by nitric acid. The apparent dissolution rate of Mo pellets containing impurity Zr was found to be followed by the first-order chemical reaction form, which is generally known as a simple chemical reaction. The rate of dissolution of sintered Mo-cermet fuels by nitric acid was found to decrease with the increase of the amount of impurity Zr.