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  • 1
    Electronic Resource
    Electronic Resource
    Deep-level electron traps in vapor phase epitaxial GaAs grown with oxygen injection (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 58 (1985), S. 825-830 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of oxygen injection on electron traps in undoped epitaxial GaAs grown in a chloride vapor phase epitaxy (VPE) system is studied using deep-level transient spectroscopy (DLTS). The trap concentrations determined from constant-capacitance DLTS agree well with those obtained from low- and high-temperature differential capacitance measurements. Layers grown with successively higher partial pressures of intentionally added oxygen each contain the same four electron traps typically observed in nonintentionally doped n-type VPE layers. Three of these traps are present in concentrations at or below the mid 1011-cm−3 range, while the dominant level known widely as EL2 remains constant at a concentration of (2.5±0.5)×1014 cm−3. However, no additional deep levels due to the oxygen are observed. Although the trap concentrations are independent of the oxygen injection, the amount of unintentional Si incorporated is reduced by almost three orders of magnitude resulting in a fourfold increase in 77-K electron mobility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.336151
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of order-disorder transition on magnetic properties of high silicon-iron single crystals (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 460-464 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using high silicon-iron single crystals containing around 6.5 wt. % silicon, the quenching temperature dependence of the saturation magnetization, the magnetocrystalline anisotropy constant, and the magnetostriction constants were measured at room temperature. The saturation magnetization and the anisotropy constant of the crystals with 4.9–6.0 wt. % silicon quenched into oil from 1100 °C showed decreases of up to 12 and 80%, respectively, compared to crystals cooled slowly from 1100 °C, while the saturation magnetostriction constants λ100 and λ111 increased for quenched crystals. The decreases in the saturation magnetizations and the anisotropy constants and the increases in the saturation magnetostriction constants for the quenched crystals were correlated with decreases in an order parameter calculated from x-ray measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.334773
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  • 3
    Electronic Resource
    Electronic Resource
    Spectroscopic studies of the influence of oxygen partial pressure on the incorporation of residual silicon impurities in vapor-phase epitaxial gallium arsenide (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 3772-3786 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The incorporation of residual shallow impurity species, in particular Si, in both chloride and hydride vapor-phase epitaxial GaAs layers grown with oxygen intentionally injected into the source zone has been studied. Photothermal ionization spectroscopy and photoluminescence show that both the Si donor and acceptor concentrations are significantly reduced by the oxygen. The observed reduction of carrier concentration and the increase in Hall mobility with increasing oxygen partial pressure are mainly due to the reduction of Si impurity concentration. Although oxygen can form deep levels as indicated by the 1.4889-eV bound-exciton line in photoluminescence, the main effect of oxygen injection is to improve the material purity by suppression of the incorporation of residual Si.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344040
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  • 4
    Electronic Resource
    Electronic Resource
    Two-photon processes in defect formation by excimer lasers in synthetic silica glass (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 1891-1893 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Defect formation in dehydrated silica glasses was investigated using various excimer lasers with different energies. The ArF laser (6.4 eV) generates the E' center more effectively than the KrF laser (5.0 eV), while the XeCl laser (4.0 eV) generated no centers. Defect generation was found to be proportional to the square of the laser photon density, indicating that it occurs dominantly due to a two-photon process which makes band-to-band excitation possible. The E' center probably originated from oxygen-deficient centers. Contributions to the E' center formation from a process involving direct absorption at the sites of intrinsic defects in SiO2 glass were discussed on the basis of the excitation energy dependence and a comparison with the effect of a low-pressure mercury lamp.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100362
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  • 5
    Electronic Resource
    Electronic Resource
    Biochemical and Immunohistochemical Studies on the Scirrhous Carcinoma of Human Stomach (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 460 (1985), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1985.tb51179.x
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  • 6
    Electronic Resource
    Electronic Resource
    Single amino acid substitutions insn-glycerol-3-phosphate dehydrogenase allozymes fromDrosophila virilis (1989)
    Springer
    Cellular and molecular life sciences 45 (1989), S. 312-314 
    Details
    ISSN: 1420-9071
    Keywords: Drosophila virilis ; sn-glycerol-3-phosphate dehydrogenase ; allozymes ; single amino acid substitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The amino acid sequence was compared among the three allelic variants (allozymes) ofsn-glycerol-3-phosphate dehydrogenase inD. virilis, which are detected by one-dimensional electrophoresis. The αGPDHf variant was different from the αGPDHm by only one substitution of 68-lysine for asparagine; αGPDHs differed from αGPDHm by substitution of 127-glycine for arginine. No electrophoretically ‘silent’ substitutions were found in a total of 352 amino acid residues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01951822
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  • 7
    Electronic Resource
    Electronic Resource
    Electrical property and defect structure of lanthanum-doped polycrystalline barium titanate (1987)
    Springer
    Journal of materials science 22 (1987), S. 4439-4445 
    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 Electrical conductivity of two types of lanthanum-doped barium titanote ceramics with different dopant levels was measured at temperatures between 900 and 1250° C andP O 2from 10−5 to 1 atm. The activation energies of the conduction for the two are interpreted in terms of the formation energy of ionized oxygen vacancies even in such a highP O 2region. This fact is in contrast with a well -known controlled -valency model proposed for rare- earth -doped semi-conducting perovskites. In a lightly lanthanum-doped specimen, semiconduction achieved at elevated temperatures is retained on cooling the specimen to room temperature, whereas in a heavily doped specimen, the resultant high-temperature semiconduction changed to insulation on cooling. The former behaviour on cooling is successfully explained by a metastabilization of oxygen vacancies accompanied by electrons formed at elevated temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01132044
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  • 8
    Electronic Resource
    Electronic Resource
    Fluorescence immunological determination of immunoglobulin G in human serum by high-performance liquid gel-permeation chromatography (1988)
    Springer
    Chromatographia 25 (1988), S. 129-133 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gel permeation ; Human serum IgG ; Fluorescent immune complex ; Fluoresence detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance liquid gel-permeation chromatographic method is described for the determination of human serum immunoglobulin G (IgG) by separating the fluorescent immuno complex from the free fluorescence-labeled antibody. Fluorescence-labeled antibody used in this study was fluorescein isothiocyanate (FITC)-labeled Fab fragment goat anti-human IgG (anti-IgG Fab). Immuno complexes and antibody of different molecular sizes can be separated. FITC-labeled anti-IgG Fab was added to the serum and the mixture is passed through the column. An immuno complex separates as well-delineated peak in the column void volume, and was measured by the fluorescence of the column eluate (Ex=490nm, Em=520nm). The total analysis time for a serum sample was approximately 15min. The minimum detection limit was 25 mg/dl. The relative standard deviation was below 2% (peak area). The results of the HPL-GPC analysis correlate well with those obtained by laser nephelometric assay (r=0.992).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259029
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  • 9
    Electronic Resource
    Electronic Resource
    Determination of haptoglobin in human serum by high-performance gel-permeation chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 89-92 
    Details
    ISSN: 1612-1112
    Keywords: Gel permeation chromatography ; Haptoglobin ; Hemoglobin ; Correlation with nephelometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance gel-permeation chromatographic (GPC) method is described for the determination of serum haptoglobin (Hp), based on the estimation of the haptoglobin-hemoglobin (Hp−Hb) complex. Hemoglobin (Hb) is added to the serum and the resulting Hp−Hb complex is separated by GPC and detected at 415 nm. The Hp−Hb complex separated chromatographically from serum migrated electrophoretically with the globulin fraction. It was found to be stable over a period of one week at 4°C. The total analysis time for a serum sample is approximately 20 min. The minimum detection limit is 30mg/L. Relative standard deviation values were below 1% (peak area). No interferences from bilirubin or from turbidity of samples were observed. The results of the GPC analysis correlate well with those obtained by nephelometric assay (r=0.996).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02312879
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  • 10
    Electronic Resource
    Electronic Resource
    Surface kinetic aspects of Si incorporation in molecular beam epitaxial growth of GaAs (1989)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 14 (1989), S. 619-622 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The incorporation and amphoteric behavior of Si impurities in Si-doped (100) oriented molecular beam epitaxial (MBE) GaAs layers grown under different As4/Ga flux ratios but with a fixed Si flux have been studied using Hall effect measurements, photothermal ionization spectroscopy and photoluminescence. The Si donor concentration increases substantially with increasing As4/Ga flux ratio, while the Si acceptor concentration remains less than ∼ 1013 cm-3, regardless of the variation of As4/Ga flux ratio. The observed increase of carrier concentration with increasing V/III ratio is not due to a change of site preference of Si impurities from Ga to As sublattice sites as previously supposed, but is due to the increase in incorporation of Si donor. This result can be explained by the kinetic effects associated with surface reaction processes involved in Si impurity incorporation. From these results it is clear that the sticking coefficient of Si is less than unity, and varies with the growth conditions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740141010
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