Analysis of Photo-Induced Waveguide in Lithium Niobate Crystal

In this letter, we estimate the refractive index distribution in a photo-induced waveguide. The photo-induced waveguide was fabricated by scanning a focused laser beam through a lithium niobate crystal. We made use of a parametric model of refractive index distribution of the photo-induced waveguide. The results of numerical simulation on the near-field patterns of curved waveguides are compared with experimental results.     

Effect of debris fragments on direct initiation of spherical detonation waves in stoichiometric oxygen/hydrogen mixtures

Paper reports a result of experiments of spherical shock waves generated by explosions of micro-explosives weighing from 1 to 10 mg ignited by the irradiation of Q-switched laser beam and direct initiation to a spherical detonation wave in stoichiometric oxygen/hydrogen mixtures at 10–200 kPa. We visualized the interaction of debris particles ejected micro-explosives’ surface with shock waves by using double exposure holographic interferometry and high-speed video recording. Upon explosion, minute inert debris launched supersonically from micro-charge surface precursory to shock waves initiated spherical detonation waves. To examine this effect we attached 0.5–2.0 μm diameter SiO₂ particles densely on micro-explosive surfaces and observed that the supersonic particles, significantly promoted the direct initiation of spherical detonation waves. The domain and boundary of detonation wave initiations were experimentally obtained at various initial pressures and the amount of micro-charges.     

Inclusion property of (R,R)-(-)-trans-2,3,-bis(hydroxydiphenylmethyl)-1,4-dioxaspiro[4,4]nonane for aromatic components

An optically active host molecule, (R,R)-(-)-trans-2,3-bis(hydroxydiphenylmethyl)-1,4- dioxaspiro[4,4]nonane (1), is able to form inclusion complexes with nonpolar aromatic components such as benzene, toluene, p-xylene, mesitylene, and ethylbenzene. The host 1 crystallizes in the monoclinic space group C2 with a = 15.694(2), b = 9.326(2), c = 18.457(1) Å, = 10.34(1)°, and Z = 4. An inclusion complex (1-B) of 1 with benzene crystallizes in the orthorhombic space group P2₁2₁2 with a = 17.007(4), b = 19.670(5), c = 8.634(4) Å, and Z = 4. An inclusion complex (1-X) involving both 1 and p-xylene has the monoclinic space group P2₁ with a = 17.211(3), b = 20.143(3), c = 8.603(3) Å, = 92.64(2)°, and Z = 2. In the inclusion complexes, molecules of 1 are dimerized by intramolecular and intermolecular hydrogen bonds forming eight-membered (OH)₄ rings. The benzene and p-xylene molecules fit into the voids of the crystal packing of 1. In addition, the inclusion complexes are stabilized by van der Waals contacts between the hydrophobic sites. Thermal analysis of the inclusion complexes indicated that the number and the size of the alkyl group of the aromatic components affects the stability of the inclusion complexes.     

High-throughput solid-phase extraction of metal ions using an iminodiacetate chelating porous disk prepared by graft polymerization

A chelating porous sheet for use in solid-phase extraction was prepared by radiation-induced graft polymerization and subsequent chemical modifications. An epoxy-group-containing vinyl monomer was graft-polymerized onto a porous sheet made of polyethylene. The produced epoxy group of the graft chain was converted into an iminodiacetate group. The chelating porous sheet with a density of the iminodiacetate group of 2.1 mol/kg was cut into disks 13 mm in diameter to fit an empty cylindrical cartridge with a capacity of 6 mL. Breakthrough curves using the chelating-porous-disk-packed cartridge overlapped irrespective of the flow rate of the solution ranging up to 1500 mL/h because of negligible diffusional mass-transfer resistance of the copper ions to the iminodiacetate group of the graft chain.     

Fusion of phosphole and 1,1'-biacenaphthene: phosphorus(V)-containing extended π-systems with high electron affinity and electron mobility

A profusion of phospholes: Diacenaphtho[1,2-b:1',2'-d]phospholes, a new class of arene-fused phosphole π-systems, were synthesized and their structural and electrochemical properties studied. The P-sulfide derivative has a high electron-transporting ability (μ(E) =2.4×10(-3) cm(2) V(-1) s(-1)) in a vacuum-deposited film.     

Vibrational properties of CaAlH5 and α-AlH3 with different AlH6 networks studied by inelastic neutron scattering

We performed a combined study using inelastic neutron scattering (INS) and first-principles calculations of the vibrational properties of CaAlH(5) and α-AlH(3) with different AlH(6) networks, a zigzag one-dimensional AlH(6) network for CaAlH(5), and a three-dimensional AlH(6) network for α-AlH(3). Both materials showed qualitatively similar INS spectra, in which CaAlH(5)/α-AlH(3) was mainly divided into three regions: (i) the translational modes (318/316 cm(-1)), (ii) the librational modes of the octahedral AlH(6) units (external molecular motion) in the lower frequency range and H-Al-H bond-bending modes (intra molecular motion) at a higher frequency (420-1157/513-1038 cm(-1)), and (iii) the Al-H bond-stretching modes (1238-1750/1486-1942 cm(-1)). In region ii, the appearance of both librational and bond-bending modes was determined by the networked nature of the octahedral AlH(6) units. In addition, the librational modes of AlH(6) on α-AlH(3) exhibit higher frequencies than CaAlH(5) due to the tighter bonding between the octahedral AlH(6) units. With regard to average frequencies for the Al-H, ω(S), bond-stretching modes, and average Al-H bond distances on the aluminum-based hydrides including CaAlH(5) and α-AlH(3), ω(S) showed lower frequencies that correlate with lengthening of the Al-H bond distances.     

Formation of dimer, trimer, and tetramer of C60 and C70 by γ-ray, charged-particle irradiation, and their HPLC separation

C₆₀ and C₇₀ fullerenes were irradiated by high-energy γ-rays and charged particles. Coalesced products of C₆₀ and C₇₀ have been isolated and detected in the liquid phase by a radiochromatographic technique. It was found that not only ¹¹C radioactive fullerene dimer, trimer, and possibly tetramer were produced by a recoil implantation process following nuclear reaction, but also such non-radioactive coalesced products were produced by the recombination process after ionization by γ-rays or charged particles.     

Examination of Dislocation Mechanism on Grain Boundary Sliding in High Angle Grain Boundaries by Stress Change Test

In order to understand the factors dominating grain boundary sliding, stress change tests and stress reversal tests were conducted on aluminum bicrystal specimens with high angle grain boundaries. It is found that small change in stress results in the remarkable change in the rate of grain boundary sliding. Stress reversal tests showed that grain boundary slide hardening does not work for the sliding to the direction opposite to that before the stress reversal. Mean internal stresses for the dislocations contributing to grain boundary sliding are experimentally measured by a method consisting of stress change and annealing. It is found that the velocity of dislocations in the grain boundary is in proportion to the mean effective stress.