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  • 1
    Online-Ressource
    Online-Ressource
    Washington :Taylor & Francis Group,
    Schlagwort(e): Electric utilities -- United States. ; Electric utilities -- Government policy -- United States. ; Electric utilities -- United States -- Management. ; Electronic books.
    Beschreibung / Inhaltsverzeichnis: Many states within the U.S., and many countries across the world, are opening their electicity markets to competition. Many others are uncertain about their plans. These differences emphasize the complexities involved in the technology and regulatory structure of the electricity industry--an industry for which the introduction of market competition has been notoriously difficult. In response to these challenges, Alternating Currents provides a timely overview and analysis of the concerns facing industry regulators, legislators, and others as they consider whether, when, and how to open electricity markets. Authors Brennan, Palmer, and Martinez offer background on the history of regulatory policy and the technology for producing and delivering electric power. They then provide insights into the policy debates and economic issues involved in eleven important topics, including industry structure, system integrity and reliability, the mitigation of market power, and environmental protection. Alternating Currents describes the recent events leading to the demise of retail competition in California with the intent on drawing lessons for the future. In the end, the authors offer their perspective about what makes electricity a unique resource and how those factors make the potential conflict between competition and reliability the most pressing of the long-term concerns about the transformation of the electric power industry.
    Materialart: Online-Ressource
    Seiten: 1 online resource (225 pages)
    Ausgabe: 1st ed.
    ISBN: 9781936331161
    DDC: 333.79320973
    Sprache: Englisch
    Anmerkung: Cover -- Alternating Currents -- Copyright -- Contents -- Preface -- About the Authors -- Introduction -- 1. Issues in Restructuring the Electricity Industry -- Part I: How the Industry Got Here -- 2. Understanding the Electricity Industry -- 3. From Regulation to Competition -- 4. International and U.S. Restructuring Experiences -- 5. The California Experience -- Part II: Current Policy Issues -- 6. Competition in Energy, Regulation of Wires -- 7. Vertical Restructuring -- 8. Regulating Rates for Transmission and Distribution -- 9. Encouraging Competition -- 10. Balancing Loads and Dispatching Power -- 11. Ensuring Reliability in a Competitive Market -- 12. State and Federal Roles -- 13. Public Power's Role after Restructuring -- 14. Covering Stranded Costs -- 15. Restructuring and Environmental Protection -- 16. Public Purpose Programs in a Competitive Market -- Part III: The Future -- 17 . Prospects for Restructuring -- Supplemental Reading -- Index.
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  • 2
    Publikationsdatum: 2021-05-19
    Beschreibung: We have investigated the thermodynamics of mixing between aragonite (orthorhombic CaCO3) and strontianite (SrCO3). In agreement with experiment, our simulations predict that there is a miscibility gap between the two solids at ambient conditions. All SrxCa1 xCO3 solids with compositions 0.12 〈 x 〈 0.87 are metastable with respect to separation into a Ca-rich and a Sr-rich phase. The concentration of Sr in coral aragonites (x 0.01) lies in the miscibility region of the phase diagram, and therefore formation of separated Sr-rich phases in coral aragonites is not thermodynamically favorable. The miscibility gap disappears at around 380 K. The enthalpy of mixing, which is positive and nearly symmetric with respect to x = 0.5, is the dominant contribution to the excess free energy, while the vibrational and configurational entropic contributions are small and of opposite sign. We provide a detailed comparison of our simulation results with available experimental data. Se investigó la actividad termodinámica existente entre la mezcla de la aragonita y el estroncio. Se ofrecen todos los datos experimentales y los resultados de la simulación efectuada predicen que hay un vacío en condiciones de ambiente.
    Beschreibung: Published
    Beschreibung: aragonita, estroncio, arrecife de coral, actividad termodinámica
    Schlagwort(e): Strontium ; Aragonite ; Coral reefs ; Thermodynamic activity ; Strontium
    Repository-Name: AquaDocs
    Materialart: Journal Contribution , Non-Refereed , Article
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  • 3
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 534-536 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Considerable modulation ratios are achieved for GaAs multiple-quantum-well reflector modulators grown on Si by inserting an AlAs/AlGaAs dielectric mirror into the device structure. Modulation ratios of up to 4:1 is attained as the external bias voltage is increased to 9 V and the 1C-1HH exciton absorption peak undergoes quantum-confirmed Stark shift. Measurements also indicate that cavity effects arising from the front surface reflection and that of the imbedded dielectric mirror strongly modify the reflectivity spectra.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 3717-3720 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Room temperature photoreflectance (PR) was utilized to determine the junction electric field in molecular-beam epitaxy (MBE)-grown modulation-doped GaAs/AlGaAs heterostructures (MDH) with varied spacer layer thickness and doping concentration. The PR spectra exhibited Franz–Keldysh oscillations (FKOs) at energies above the GaAs band gap. Linear regression from the energy plots of the FKO extrema allowed for the calculation of the junction electric field strengths. High junction electric fields of magnitude 270–430 kV/cm were obtained from the samples. These measured fields were almost a factor of two higher than what can be accounted for by the measured carrier concentration. The presence of impurities introduced during the growth process, which could account for the added field strength, was checked by photoluminescence (PL) spectroscopy at 10 K. The similar PL spectra of the samples with different electric field strength ruled out carbon as the source of added field observed. Deep level transient spectroscopy (DLTS) measurement performed on MBE-grown Si-doped GaAs revealed electron traps corresponding to M4 and EL2. M4 is an impurity-related trap involving As vacancies while EL2 is an As-antisite trap. Although DLTS was not performed directly on MDH samples, results in the doped GaAs indicate As-related electron traps as the possible cause of the added field observed by PR. © 2002 American Institute of Physics.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 594-596 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The emission and reflection spectra of GaN have been investigated in the intrinsic region and the data have been interpreted in terms of the wurtzite crystal band structure. Three intrinsic exciton transitions have been observed, one associated with each of the valence bands. Exciton excited states associated with the two top valence bands were also observed. The exciton binding energies, the band-gap energies, and the exciton Bohr radii are all reported along with the dielectric constant and the spin-orbit and crystal-field parameters for GaN. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Continuous-wave and time-resolved photoluminescence spectroscopies have been employed to study the band-edge transitions in GaN epitaxial layers grown by plasma assisted molecular beam epitaxy. In addition to the neutral-donor-bound exciton transition (the I2 line), a transition line at about 83 meV below the band gap has been observed in an epitaxial layer grown under a lower plasma power or growth rate. This emission line has been assigned to the band-to-impurity transition resulting from the recombination between electrons bound to shallow donors and free holes D0, h+). Systematic studies of these optical transitions have been carried out under different temperatures and excitation intensities. The temperature variation of the spectral peak position of the D0, h+) emission line differs from the band gap variation with temperature, but is consistent with an existing theory for D0, h+) transitions. The dynamic processes of the D0, h+) transition have also been investigated and subnanosecond recombination lifetimes have been observed. The emission energy and the temperature dependencies of the recombination lifetime have been measured. These results have provided solid evidence for the assignment of the D0, h+) transition and show that the motions of the free holes which participated in this transition are more or less restricted in the plane of the epitaxial layer at temperatures below 140 K and that the thermal quenching of the emission intensity of this transition is due to the dissociation of neutral donors. Our results show that time-resolved photoluminescence spectroscopy can be of immense value in understanding the optical recombination dynamics in GaN. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 7657-7666 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: High quality GaN layer growth by reactive molecular beam epitaxy employing ammonia gas as a nitrogen source and with high growth rates (∼2 μm/h) is described. The high crystalline quality of the layer is evidenced by our recently reported modulation-doped field-effect transistors, GaN/AlGaN separate confinement heterostructures, GaN/AlGaN quantum wells, high quality Schottky contacts, long excitonic lifetime, and GaN epitaxial layers that exhibit only intrinsic transitions even with the second excited states of excitonic transitions visible in the emission spectra. The dependence of background carrier concentration and resistivity on substrate temperature is studied. The hexagonal nature of wurtzite GaN manifests itself as hexagonal features on the film, becoming as large as ∼5 μm with facets at high growth temperatures (e.g., 800 °C). For low V/III ratios, large hexagonal hillocks, with highly strained regions on them, are formed due to the localized preferential growth. The photoluminescence characteristics of the films grown with various V/III ratios are also studied. The PL spectra were analyzed to uncover the effect of substrate temperature on the crystalline quality, as well as on electrical and optical properties of films. The ground and excited state excitons were seen from the layer grown at 800 °C with a growth rate of 1.2 μm/h. The influence of two competing factors, viz., thermal activation of ammonia and thermal desorption of Ga from the surface, on the growth kinetics was investigated. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 3920-3924 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The effects of anodic (NH4)2S passivation of n-GaAs Schottky diodes have been investigated. When these Schottky diodes are prepared on anodically treated n-GaAs in (NH4)2S solution, the Schottky barrier height is lowered by at least 200 meV, and the interface trap density is estimated to be 5.5×1012 cm−2 which is two orders less than that of the untreated sample. It is observed that the Schottky barrier height or the position of the Fermi level at the surface is not stable for samples treated with a small current density (∼83 μA/cm2), but is significantly stable for samples treated with a large current density (∼1 mA/cm2). The stability of passivation is sensitive to the photon energy of the excitation source. Although for a longer-wavelength (λ=514 nm) illumination the passivation is stable, for a shorter-wavelength (λ=325 nm) illumination, the passivation is unstable. The photoluminescence intensity is found to rapidly decay due to photon-assisted oxidation. As compared to the (NH4)2S dip treatment, the anodic (NH4)2S treatment improves the stability of passivation. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 4455-4458 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: GaN growth mediated by electron cyclotron resonance activated nitrogen has been investigated under Ga and nitrogen rich conditions in a substrate temperature range of 650–850 °C. A biasable grid installed between the substrate and nitrogen flux allowed control of the nitrogen species participating in the growth process. The absence of high energetic ions resulted to films with increased photoluminescence signals in the 480–650 nm spectral range. In the Ga rich conditions, the Ga and N ion flux values used were 5×1014 and 3.5×1014 cm−2 s−1, respectively. The nitrogen rich conditions were achieved by increasing the N flux first to 8×1014 and then to 1.2×1015 cm−2 s−1. Both types of samples exhibited strong band edge photoluminescence signal at room temperature, with N rich conditions leading to better mobilities and lower carrier concentrations. The best films were obtained when the substrate temperature was 750 °C. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 2960-2963 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Molecular-beam-epitaxial GaN layers change from strongly conductive (ρ(approximately-equal-to)10−2 Ω cm at 300 K) to semi-insulating (ρ(approximately-equal-to)106 Ω cm) as the N flux is increased. Layers grown at low fluxes show strong n-type conduction, with transport in the conduction band at high temperatures and in a shallow donor band at low temperatures. For layers grown at high N fluxes, the Hall coefficients become too small to measure, suggesting hopping conduction among deep centers. The temperature-dependent resistivity data are most consistent with multiphonon, rather than single-phonon, hopping. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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