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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 253-255 
    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
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Inorganic chemistry 19 (1980), S. 1249-1251 
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 877-879 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A transverse mode stabilized GaAlAs laser diode which includes a ZnSe layer for the waveguide has been developed. The double heterostructure of the GaAlAs laser is formed by low-pressure metalorganic chemical vapor deposition (MOCVD), and a ZnSe layer is grown by adduct-source MOCVD in order to block the injection current and change the real refractive index in the lateral direction. The fundamental transverse mode oscillation of more than 15 mW is obtained with a low threshold current of 28 mA and a high quantum efficiency of 76%. An output power as high as 25 mW is achieved.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 1289-1291 
    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
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 20 (1973), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: By macroautoradiography and by GLC separation, differences in the uptake of radioactive carbon from [U-14C]glucose into free amino acids (glutamate + glutamine, aspartate + asparagine, GABA, alanine and glycine) in mouse cerebral neocortex, hippocampus, thalamus and hypothalamus were investigated.(1) The autoradiographical densities in the thalamus, cerebral neocortex and hippocampus measured with a microdensitometer were higher than that in the hypothalamus at 5 min after subcutaneous injection. At 180 min, densities in the cerebral neocortex, hippocampus and hypothalamus were higher than that in thalamus.(2) The free amino acid levels determined by GLC varied with each brain region.(3) The specific radioactivity (d.p.m./μmol) of alanine in each brain region was higher than that of the other amino acids at 5 min after the injection. The specific radioactivity of GABA in the brain regions was clearly higher than that of (glutamate + glutamine), (aspartate + asparagine) and glycine at 5 and 15 min.(4) The autoradiographical data were in good agreement with the chemical data at 5 min but were different at 180 min.(5) Variations in specific radioactivity of each free amino acid among brain regions at 5 min were influenced greatly by existing free amino acid concentrations in each region.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 23 (1974), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: —During anoxia induced by the administration of potassium cyanide, [U-14C]glucose was injected intraperitoneally into adult mice and they were decapitated at 5, 15 and 30 min after the injection. After freeze-drying in vacuo, differences in the uptake of radioactive carbon from [U-14C]glucose into free amino acids (glutamate + glutamine, aspartate + asparagine, GABA, alanine and glycine) in mouse cerebral neocortex, cerebellar hemisphere, caudate nucleus, thalamus, hypothalamus and medulla oblongata were investigated (by macroautoradiography and GLC separation) and compared with those obtained under normal conditions.(1) During anoxia, autoradiographical densities in the thalamus and medulla oblongata were higher than that in the cerebral neocortex and caudate nucleus.(2) Among specific radioactivities (d.p.m./μmol) of free amino acids, alanine gave the highest value during anoxia, except in the cerebellar hemisphere and hypothalamus at 5 min and the medulla oblongata at 30 min.(3) During anoxia, the specific radioactivities of alanine and glycine in each brain region did not significantly decrease at 15 and 30 min compared with those under normal conditions. During anoxia, the specific radioactivity of glutamate + glutamine in the cerebellar hemisphere and hypothalamus did not significantly decrease compared with the normal conditions, while that of GABA, aspartate + asparagine and glutamate + glutamine in the cerebral neocortex, caudate nucleus, thalamus and medulla oblongata showed an increase.(4) The percentage decrease of glutamate + glutamine and aspartate + asparagine at 5 and 15 min was highly significant in the cerebral neocortex and caudate nucleus.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The soft x-ray continuum radiation in tokamak fusion test reactor (TFTR) low-density neutral-beam discharges can be much lower than its theoretical value obtained by assuming a corona equilibrium. This reduced continuum radiation is caused by an ionization equilibrium shift toward lower states, which strongly changes the value of the average recombination coefficient of metallic impurities γ¯, even for only slight changes in the average charge Z¯. The primary agent for this shift is the charge exchange between the highly ionized impurity ions and the neutral hydrogen, rather than impurity transport, because the central density of the neutral hydrogen is strongly enhanced at lower plasma densities with intense beam injection. In the extreme case of low-density, high neutral-beam power TFTR operation (energetic ion mode) the reduction in γ¯ can be as much as one-half to two-thirds. We calculate the parametric dependence of γ¯ and Z¯ for Ti, Cr, Fe, and Ni impurities on neutral density (equivalent to beam power), electron temperature, and electron density. These values are obtained by using either a one-dimensional impurity transport code or a zero-dimensional code with a finite particle confinement time. As an example, we show the variation of γ¯ and Z¯ in different TFTR discharges.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 2151-2153 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Metal impurity concentrations are measured by the pulse-height-analyzer (PHA) diagnostic from Kα x-ray peak intensities by use of an averaged excitation rate 〈σv〉. Low-Z impurity concentrations are inferred from the continuum enhancement (relative to a pure plasma) minus the enhancement due to metals. Since the PHA does not resolve lines from different charge states, 〈σv〉 is a weighted sum of rates; coronal equilibrium is usually assumed. The 〈σv〉 used earlier omitted the intercombination and forbidden lines from the dominant heliumlike state. The result was an overestimate of metals and an underestimate of low-Z impurities in cases where metals were significant. Improved values of 〈σv〉 using recent calculations for H-, He-, and Li-like Fe range from 10% to 50% larger than the earlier rates and yield metal concentrations in better agreement with those from vacuum ultraviolet (VUV) spectroscopy.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 8 (1996), S. 3379-3402 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Low-Reynolds-number type k−cursive-epsilon and kt−cursive-epsilont models have been constructed with the aid of direct numerical simulation (DNS) databases. The proposed models incorporate new velocity and time scales to represent various sizes of eddies in velocity and thermal fields with different Prandtl numbers. The validity of the present k−cursive-epsilon model was tested by application to basic and complex flows such as flows with injection and suction, flows with strong adverse and favorable pressure gradients, and flows with separation and reattachment, while comparing the relevant DNS and reliable experimental data. Fundamental properties of the proposed kt−cursive-epsilont model were first verified in basic flows under arbitrary wall thermal boundary conditions and next in backward-facing step flows at various Prandtl numbers through a comparison of the predictions with the DNS and measurements. These comparisons have proven that the proposed models for both velocity and thermal fields have wide applicability to science and engineering and have sufficient capability to perform highly stable computations at any Prandtl numbers, irrespective of flow configurations. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 294-296 
    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
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