Monolithic wavelength converter for ultraviolet light by use of a Gd(x)Y(1-x)Ca4O(BO3)3 crystal

Gd(x)Y(1-x)Ca4O(BO3)3 (GdYCOB) is a promising nonlinear optical crystal that shows high effective nonlinearity d(eff), noncritical phase matching, and high chemical stability. We report on the fabrication and characteristics of a monolithic wavelength converter, which generates ultraviolet light by the incidence of a 1.064 microm near-infrared laser. The converter consists of GdYCOB for third-harmonic generation, KTiOPO4 (KTP) for second-harmonic generation, and a wave plate. GdYCOB has the advantage of an extremely wide angular acceptance bandwidth, whereas KTP exhibits a high effective nonlinear coefficient and a broad temperature bandwidth. Consequently the combination of these crystals results in highly efficient and stable ultraviolet conversion for constructing a compact and robust ultraviolet laser.     

Orientation dependence of internal friction in artificial single crystals of ice

The internal friction of artificial single crystals of ice is studied by the flexural vibration method, changing temperature, frequency and angle θ between the crystal c-axis and the long axis of the specimen. The height of the main peak in the curve of the internal friction (tan δ) versus temperature depends strongly on the angle θ. The maximum damping (tan δ_max) increased with increase in the angle θ up to nearly 60° and decreased a little for values of θ greater than 60°. The results of the experiments except for θ = 0° show that the internal friction peak is caused by a single relaxation phenomenon, the relaxation time of which is τ = τ₀exp (H/kT). Values of τ₀ and H are 1.66 × 10^?16 s and 0.60 eV, respectively.The data are compared with the other experiments and are discussed with special reference to the theoretical treatments by Bass. The orientation dependence of tan δ_max is found to be consistent with the theoretical prediction.     

Alteration of T-lymphocyte subpopulations in patients with primary renal diseases and systemic lupus erythematosus

Forty-eight patients with a variety of primary renal diseases and systemic lupus erythematosus (SLE) were examined for the proportion of circulating T lymphocytes bearing receptors for IgM (T mu cells) or IgG (T gamma cells). Although the control group showed strikingly similar mean values for both T mu and T gamma cells, the whole group of patients with primary renal diseases and SLE showed a wide scatter of values. Sixteen patients with primary renal diseases and SLE had higher proportions of T gamma cells than the control group, whereas seven patients with chronic glomerulonephritis (CGN), membranoproliferative glomerulonephritis (MPGN), lipoid nephrosis (LN), and SLE showed very marked decrease in the proportions of T gamma cells in the peripheral blood. On the other hand, six out of the total group of patients had low proportions of T mu cells in the peripheral blood. However, no consistent relationship between the proportion of T mu and T gamma cells was found in our study. These findings indicate that there exists a heterogeneity of T-lymphocyte subpopulation distribution in some patients with primary renal diseases and SLE. The possible significance of these phenomena in the pathophysiology of renal diseases is discussed.     

The flow of solid particles in an aerated inclined channel

The dynamic behavior of the flow of solid particles in an inclined open channel with air flow introduced through a porous base plate was examined. The solid particle velocity distributions were measured in detail using an optical probe.Five types of flow patterns were found depending on the air velocity and the slope of the channel. They were: sliding flow, immature sliding flow, splashing flow, bubbling flow, and gliding flow. The first two could be observed when the air velocity was less than the minimum fluidization velocity, U_mf, for the particles. The last two were observed when it became higher than U_mf. Splashing flow occurred when the slope of the channel was steep.     

Basic study of aerial flashover characteristics generated from pore of insulating solid

This paper reports a study on the possibility of an aerial flashover between a coil conductor and a casing in rotating machines under the application of a lower voltage than Paschen's voltage, even when enough insulation distance is secured. The time lag to aerial flashover originating from surface flashover was measured. To understand the aerial flashover influenced by the parameters of the voltage application circuit, the aerial flashover distance was measured using a cable which had a simulated pore to confirm the above issue. The surface flashover characteristic was also measured using a photomultiplier tube (PMT). It became clear that aerial flashover occurred a few milliseconds after surface flashover generation. After showing the peak, the aerial flashover distance decreased with increasing time constant. The surface flashover time estimated by the PMT output exhibited different values with change of capacitance when the time constant is larger. On the other hand, the average surface flashover current was almost the same in spite of the change of capacitance. From these results, it was concluded that the aerial flashover distance was influenced by the time constant of the circuit. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(3): 9–17, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21295     

Synthesis of C2H4 by partial oxidation of CH4 over LiCl/NiO

Alkali halide added transition metal oxides produced ethylene selectively in oxidative coupling of methane. The role of alkali halides has been investigated for LiCl-added NiO (LiCl/NiO). In the absence of LiCl the reaction over NiO produced only carbon oxides (CO₂ + CO). However, addition of LiCl drastically improved the yield of C₂ compounds (C₂H₆ + C₂H₄). One of the roles of LiCl is to inhibit the catalytic activity of the host NiO for deep oxidation of CH₄. The reaction catalyzed by the LiCl/NiO proceeds stepwise from CH₄ to C₂H₄ through C₂H₆ (2CH₄ → C₂H₆ → C₂H₄). The study on the oxidation of C₂H₆ over the LiCl/NiO showed that the oxidative dehydrogenation of C₂H₆ to C₂H₄ occurs very selectively, which is the main reason why partial oxidation of CH₄ over LiCl/NiO gives C₂H₄ quite selectively. The other role of LiCl is to prevent the host oxide (NiO) from being reduced by CH₄. The catalyst model under working conditions was suggested to be the NiO covered with molten LiCl. XPS studies suggested that the catalytically active species on the LiCl/NiO is a surface compound oxide which has higher valent nickel cations (Ni^(2+δ)+ or Ni³⁺). The catalyst was deactivated at the temperatures>973 K due to vaporization of LiCl and consumption of chlorine during reaction. The kinetic and CH₄---CD₄ exchange studies suggested that the rate-determining step of the reaction is the abstraction of H from the vibrationally excited methane by the molecular oxygen adsorbed on the surface compound oxide.     

Preparation of therapeutic phospholipids through porcine pancreatic phospholipase A2-mediated esterification and lipozyme-mediated acidolysis

Highly unsaturated fatty acid-containing phospholipids (HUFA-PL), which serve to increase the deformability of human red blood cells, were prepared through porcine phospholipase A₂-mediated esterification of the lysophosphatidylcholine, which was derived from soy phosphatidylcholine (PC), and by Lipozyme-mediated acidolysis. Through these processes, phospholipase A₂, with formamide as a water mimic, enhanced the incorporation of HUFA into positionsn-2 of PC and suppressed hydrolysis of the synthesized PL. On the other hand, Lipozyme-mediated acidolysis between positionsn-1 of soy PC and HUFA was enhanced by a combination of water and propylene glycol. Simultaneously, the recovered PL products showed decreased hydrolysis of newly synthesized health-beneficial HUFA-PL.     

Characteristic long-chain fatty acid of Pleurocybella porrigens

As part of an investigation on the chemical constituents and contaminants of the basidiomycete Pleurocybella porrigens (Japanese name: Sugihiratake), we analyzed the UV-detected constituents of this mushroom using HPLC. One of the major UV peaks detected was isolated and identified as a-eleostearic acid, a long-chain fatty acid with a conjugated triene moiety, based on the results of spectroscopic methods. alpha-Eleostearic acid was concluded to be a characteristic fatty acid of P. porrigens, because it was not detected in eight other edible mushrooms examined. Free long-chain fatty acids in P. porrigens and other edible mushrooms were analyzed by HPLC after derivatization with acidic 2-nitrophenylhydrazine hydrochloride. Oleic acid was the main fatty acid in P. porrigens, and saturated long-chain fatty acids such as linoleic acid, palmitic acid, and stearic acid, together with a-eleostearic acid, were also detected.     

Tritium depth profile in matter using an imaging plate

A method to detect tritium non-destructively in regions deeper than the escape depth of beta rays is being developed using bremsstrahlung induced by beta rays with an imaging plate (IP). An IP made of europium-doped BaFBr(I), a photostimulated luminescence (PSL) material, is a two-dimensional radiation sensor. The bremsstrahlung energy spectrum is a continuum with photon energies, varying based on the atomic number and thickness of the target (or absorbing) material. When tritium migrates into matter, the bremsstrahlung energy spectrum distribution would change. The PSL intensity of the IP is affected by this energy spectrum variation. In order to quantify the amount of tritium in deeper regions with the IP technique, a tritium depth profile is required.In this study, a new method of obtaining a tritium depth profileusing the combined technique of the IP and thin absorbers is presented.