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  • 1
    Electronic Resource
    Electronic Resource
    Development and experiments of a MEVVA ion source : Proceedings of 5th international conference on ion sources (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1281-1283 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The MEVVA ion source presented in the present paper adopts the arc discharge mechanism with a cathode changeable by a motor for pushing in, and an accel–decel three-grid extraction system. The voltage proof level is higher than 60 kV, the ion source generally runs at a voltage of 40 kV, the average beam current is higher than 5 mA, the beam spot is about 150 mm in diameter, and the nonuniformity of beams is within ±20%. Measurements of the beam radial profile show that there is a platform of about 40 mm in diameter in the central region. Ion beams and their optimal operation conditions for the cathode materials Al, Ti, Cr, Fe, Ni, Cu, Y, Zr, Mo, Ta, W, C, LaB6, etc., have already been obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144982
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  • 2
    Electronic Resource
    Electronic Resource
    Photoluminescence of Sm doped porous silicon—evidence for light emission through luminescence centers in SiO2 layers (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 3282-3284 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: After oxidation promoted by gamma-ray irradiation, in the photoluminescence (PL) spectra of Sm doped porous silicon (PS), there are three sharp peaks, superimposed on a broad band, with wavelengths near to those of the Sm doped SiO2 [R. Morimo, T. Mizushima, and H. Okumura, J. Electrochem. Soc. 137, 2340 (1990)]. The experimental results indicate that Sm-related luminescence centers can be created within the oxide of porous silicon, and only in porous silicon with high porosity can the Sm-related luminescence be found in the SiO2 layer. This experimental result can be explained by the fact that the excitation of electron-hole pairs occurs in nanoscale silicon, and the recombination occurs at the Sm-related luminescence centers in SiO2 layers covering nanoscale silicon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.111310
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  • 3
    Electronic Resource
    Electronic Resource
    Photoluminescence of copper-doped porous silicon (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 2855-2857 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this letter, we report the results of copper-doped porous silicon. In the photoluminescence spectrum of porous silicon without Cu doping, only one red luminescence band appears with a peak at 676.5 nm; while in the photoluminescence spectrum of Cu-doped porous silicon, red and near infrared luminescence bands appear with peaks at 660.6 and 802.2 nm, respectively. Energy dispersive x-ray spectroscopy and Fourier transform infrared spectroscopy indicate the near infrared luminescence band is related to copper impurity in porous silicon. We assign the red luminescence band to band-to-band emission, and the near infrared luminescence band to band-to-acceptor emission. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117341
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  • 4
    Electronic Resource
    Electronic Resource
    Positron irradiation: A technique for modifying the photoluminescent structures of porous silicon (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 3850-3852 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: It has been shown that a two-peak green photoluminescence (PL) of porous silicon (PS) can be obtained from a continuous blueshift of a red PL by positron irradiation. At room temperature, PS samples were irradiated in air by energetic positrons coming from the conventionally used isotope 22Na (∼20 μCi). With increasing positron irradiation time, an originally red PL shifted continuously to green, then a two-peak PL appeared with a weak high-energy emission band (529 nm) and a low-energy dominant band (562 nm). The intensity of this high-energy band was enhanced by prolonged positron irradiation. The electron-spin-resonance signal combined with infrared absorption showed that positron irradiation created dangling bonds and stimulated oxide growth in PS. An interpretation is given on the basis of quantum confinement and atomiclike nature for very small nano-Si crystallites. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120523
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  • 5
    Electronic Resource
    Electronic Resource
    Estimates of uncertainties in analysis of positron lifetime spectra for metals (1978)
    Springer
    Applied physics 15 (1978), S. 65-71 
    Details
    ISSN: 1432-0630
    Keywords: 78.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The effects of uncertainties and errors in various constraints used in the analysis of multi-component life-time spectra of positrons annihilating in metals containing defects have been investigated in detail using computer simulated decay spectra and subsequent analysis. It is found that the errors in the fitted values of the main components lifetimes and intensities introduced from incorrect values of the instrumental resolution function and of the source-surface components can easily exceed the statistical uncertainties. The effect of an incorrect resolution function may be reduced by excluding the peak regions of the spectra from the analysis. The influence of using incorrect source-surface components in the analysis may on the other hand be reduced by including the peak regions of the spectra. A main conclusion of the work is that extreme caution should be exercised to avoid introducing large errors through the constraints used in the analysis of experimental lifetime data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00896892
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  • 6
    Electronic Resource
    Electronic Resource
    Determining the three individual stress components from measured isochromatic fringes (1991)
    Springer
    Experimental mechanics 31 (1991), S. 310-318 
    Details
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper combines measured isochromatic information, complex stress functions and numerical concepts into a new and effective hybrid method of stress analysis. The technique simultaneously smooths the measured isochromatic data, provides accurate boundary information, and separates the isochromatic information into normal and shear stresses at nonboundary locations. No additional experimental data such as the isoclinics are needed. The technique is illustrated experimentally by application to a tensile plate containing a hole.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02325987
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  • 7
    Electronic Resource
    Electronic Resource
    Hybrid elastostatic and thermostatic analysis from measured data (1989)
    Springer
    Experimental mechanics 29 (1989), S. 474-480 
    Details
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An effective hybrid method is demonstrated for stress analysis and heat transfer. Measured information is represented and differentiated analytically, while the number of unknown coefficients and amount of experimental input data needed are reduced through field equations. The approach is accurate, full-field, employs arbitrarily shaped elements, does not require a smoothing parameter and is well suited for computer-vision techniques. The concept is presently illustrated by moiré strain analysis, although it can be extended to other disciplines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02323870
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  • 8
    Electronic Resource
    Electronic Resource
    Simultaneous stress separation, smoothing of measured thermoelastic isopachic information and enhanced boundary data (1990)
    Springer
    Experimental mechanics 30 (1990), S. 398-403 
    Details
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A new thermoelastic hybrid method of stress analysis is demonstrated experimentally which simultaneously smooths the measured isopachic data, enhances the boundary information, and separates the stresses at nonboundary locations using only the isopachics. The technique is illustrated by application to a tensile plate containing a hole.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02321511
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  • 9
    Electronic Resource
    Electronic Resource
    Determination of individual stresses thermoelastically (1990)
    Springer
    Experimental mechanics 30 (1990), S. 88-94 
    Details
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Hybrid methods are developed for determining individual stress components under plane stress from thermoelastically measured isopachics. Some of the techniques depend only on stress equilibrium and are independent of constitutive response. Applications are to a partially loaded half-plane, and tensile plates containing side notches and holes. These are believed to represent the first examples of separating stresses from thermoelastically measured data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02322708
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  • 10
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    Positron irradiation: A technique for modifying the photoluminescent structures of porous silicon (1997)
    American Institute of Physics
    Details
    Publication Date: 1997-12-29
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Published by American Institute of Physics
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