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  • 1
    Electronic Resource
    Electronic Resource
    Oxygen-radical-mediated toxic effects of the red tide flagellate Chattonella marina on Vibrio alginolyticus (1992)
    Springer
    Marine biology 112 (1992), S. 505-509 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Toxic mechanisms of the red tide flagellate, Chattonella marina, collected in 1985 from Kagoshima Bay, Japan, were studied at the subcellular level. C. marina was found to reduce ferricytochrome c at a rate related to the concentration of plankton cells. Ca. 50% of the cytochrome c reduction was inhibited by the addition of 100 U superoxide dismutase ml-1. These results suggest that a part of the cytochrome c reduction was caused by a superoxide anion which was extracellulary released from C. marina. Moreover, a small amount of hydrogen peroxide was detected in the C. marina suspension using the fluorescence spectrophotometric assay method. The identity of the hydrogen peroxide was confirmed by its reaction with 500 U catalase ml-1. It is thus proposed that C. marina produces harmful active oxygen radicals and therefore exhibits a toxic effect on surrounding living organisms. In agreement with these results, C. marina strongly inhibited the proliferation of marine bacteria, Vibrio alginolyticus, in a plankton/bacteria co-culture system. The growth inhibition of bacteria caused by C. marina was related to the density and the metabolic potential of C. marina. Ruptured plankton showed no toxic effect on the bacteria. Furthermore, the toxic effect of C. marina on V. alginolyticus was completely suppressed by the addition of catalase and superoxide dismutase. In addition to these radical-scavenging enzymes, a chemical scavenger, sodium benzoate, also had a protective effect. These results suggest that oxygen radicals are important in the toxic action of C. marina.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00356297
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  • 2
    Electronic Resource
    Electronic Resource
    A high-current density and long lifetime ECR source for oxygen implanters : International conference on ion sources (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 253-255 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A high-current ECR source has been developed for oxygen implanters for use in fabricating separation by implanted oxygen (SIMOX) substrates. The new source has the following features: (1) high-current density (150 mA/cm2) and large extracted current (more than 200 mA), (2) stable and long lifetime operation (more than 200 h), (3) high O+ ratio (more than 80%), and (4) low-divergence beam. The improved performance is obtained by incorporating the following: (1) Localized high-density plasma generation at the center of the plasma chamber. (2) A newly developed multilayer window to satisfy two requirements: efficient coupling of the microwave with high-density plasma and high resistance to high-speed backstream electrons. (3) Optimized combination of plasma chamber length and axial magnetic field distribution. (4) Sophisticated compact magnetic circuit that yields the optimum magnetic field for obtaining high-density plasma. An industrial-version ECR source was developed for production use on EATON NV-200 implanters. The source was installed on an NV-200 and used to implant oxygen ions to Si wafers. Good performance compared to a duopigatron source was obtained in terms of beam transport efficiency and reliability of source operation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141311
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  • 3
    Electronic Resource
    Electronic Resource
    High current ECR source for oxygen implantation: Life tests and comparison to duopigatron performance : International conference on ion sources (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 294-296 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An ECR source has been built for production use on Eaton's NV200 oxygen implanter. It can be retrofitted in place of the duopigatron normally used on that machine. This article reports results of 200 continuous hours of operation of the source, producing 95 mA of O+ ions, on a special test stand which emulates the injector of the NV200. Currents up to 200 mA at 45 kV were briefly obtained on this stand, the upper limit being set by thermal capacity of the beam dump. The ECR source was installed on an NV200 and used to implant wafers at 200 keV. Its performance is compared to that of the duopigatron source under similar conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141326
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  • 4
    Electronic Resource
    Electronic Resource
    Low-threshold surface-emitting laser diodes with distributed Bragg reflectors and current blocking layers (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 1289-1291 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: AlGaAs/GaAs surface-emitting laser diodes (SELDs) with distributed Bragg reflectors (DBRs) and current blocking layers are fabricated with the combination of a two-step epitaxial growth and the reactive ion beam etching (RIBE) technique. An Al0.1Ga0.9As/Al0.7Ga0.3As multilayer and an amorphous silicon (a-Si)/silicon dioxide (SiO2) multilayer are employed for the lower and upper mirrors, respectively. The active region has a 5×5 μm or 4 μm φ area and a 0.8 μm thickness. The minimum threshold current is 3.3 mA under pulsed condition and 4.1 mA under continuous wave (cw) operation at 12 °C with junction-side-up configuration. Stable single longitudinal mode is observed, and far-field pattern (FFP) indicates higher transverse mode operation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104096
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  • 5
    Electronic Resource
    Electronic Resource
    Generation of superoxide anions byChattonella antiqua: Possible causes for fish death caused by ‘Red Tide’ (1992)
    Springer
    Cellular and molecular life sciences 48 (1992), S. 888-890 
    Details
    ISSN: 1420-9071
    Keywords: Red Tide ; Chattonella antiqua ; superoxide anions ; free radical ; ESR ; microvoltammetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The generation of reactive free radicals byChattonella antiqua (‘Red Tide’), which may be a causative factor in fish death, has been demonstrated by electron spin resonance spectroscopy and a microelectrode technique. Electrochemical detection indicates that superoxide anions are produced as a primary product, and undergo further reactions during diffusion in glycocalyx to produce hydrogen, hydroxy-, and carbon-centered radicals which are detected by ESR as secondary products. It is proposed that these reactive radicals are responsible for the destruction of the mucous membranes of fish on exposure to ‘Red Tide’.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02118427
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  • 6
    Electronic Resource
    Electronic Resource
    Corrosion of silicon nitride ceramics under hydrothermal conditions (1991)
    Springer
    Journal of materials science 26 (1991), S. 1749-1754 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Corrosion behaviour of Si3N4 ceramics containing Y2O3, Al2O3 and AIN as sintering aids was investigated under hydrothermal conditions at 200–300
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00543597
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  • 7
    Electronic Resource
    Electronic Resource
    Preparation and characterization of quenched KNbO3-Nb2O5 glass (1991)
    Springer
    Journal of materials science 26 (1991), S. 510-516 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract KNbO3-Nb2O5 glasses were prepared with molar ratio of K/(K + Nb) from 0.16 to 0.5 by using a twin-roller quenching apparatus. Most KNbO3-Nb2O5 glasses crystallized to stable phases such as KNbO3, K2Nb4O11, K3Nb7O19, KNb3O8 and K2Nb8O21 via metastable phases after heat treatment and K4Nb6O17 glass directly crystallized to K4Nb6O17 crystal. KNbO3 glass consisted of the corner-shared NbO6 octahedra, while the amounts of the edge-shared NbO6 octahedra in the KNbO3-Nb2O5 glass structure increased with decreasing K+ ion content. The band gap energies and the ionic conductivity of the KNbO3-Nb2O5 glasses increased with increasing K+ ion content, but the density and the activation energy of the ionic conduction decreased. The glasses possessed high dielectric constants appfoaching those of ferroelectric crystals at high temperature around the crystallization temperature. The dielectric constants of the glasses, however decreased greatly with decreasing temperature and with increasing frequency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00576551
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  • 8
    Electronic Resource
    Electronic Resource
    Sintering and mechanical properties of β-wollastonite (1994)
    Springer
    Journal of materials science 29 (1994), S. 1501-1506 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Detailed microstructural studies have been carried out on porous β-wollastonite (CaSiO3) ceramics with 40–60% of the theoretical density. Xonotlite (Ca6Si6O17(OH)2) was used as starting material, and the reaction and sintering behaviour were systematically examined in the range 800–1200 °C in air. Analysis of the mechanical properties showed that the strength degradation of β-wollastonite ceramics was certainly induced by the change of microstructure. Isothermal annealing at 1100 °C, however, did not preferentially affect the microstructure or the mechanical properties of sintered β-wollastonite. These observations lead to the conclusion that the measured bending strength and Vickers hardness of porous β-wollastonite ceramics can be substantially modified and improved by controlling the microstructure, in particular due to the shape of randomly oriented grains in the matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00368916
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  • 9
    Electronic Resource
    Electronic Resource
    Corrosion of S3N4 and sialons in V2O5 melts (1990)
    Springer
    Journal of materials science 25 (1990), S. 1231-1236 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Si3N4 based ceramics such as hot isostatically pressed Si3N4, hot pressed Si3N4, hot pressed sialons containing 0, 30, 60 and 100% ofα phase were corroded by V2O5 melts at 700 to 1000
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00585429
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  • 10
    Electronic Resource
    Electronic Resource
    Hydrothermal corrosion of magnesiapartially-stabilized zirconia (1991)
    Springer
    Journal of materials science 26 (1991), S. 1346-1350 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Changes in the phase compositions and microstructures of magnesia-partially-stabilized zirconia (Mg-PSZ) were studied in water at 80–300 °C, 1 m HCl solutions at 80–140 °C and 1 m CH3COOH-CH3COONa buffer solutions at pH 3 and 80–140 °C for 10–40 days. The tetragonal to monoclinic phase transformation and the degradation of the fracture strength occurred in water above 200 °C. On the other hand, although no noticeable tetragonal to monoclinic phase transformation proceeded in 1 m HCl solutions and 1 m CH3COOH-CH3-COONa buffer solutions at pH 3 below 140 °C, the fracture strength of Mg-PSZ greatly degraded. The dissolution of Mg2+ ion was observed in water above 200 °C and in 1 m HCl solutions above 80 °C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00544475
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