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  • 1
    Publication Date: 2023-01-13
    Description: Management of hydropower plants strongly influences streamflow dynamics and hence the interaction between surface water and groundwater. As dam operations cause variations in river stages, these can result in changes in the groundwater level at multiple temporal scales. In this work, we study the case of an Alpine aquifer, where weekly fluctuations are particularly pronounced. We consider an area with four river reaches differently impacted by reservoir operations and investigate the influence of these rivers on the common aquifer. Using continuous wavelet transform and wavelet coherence analysis, we show that weekly fluctuations in the groundwater table are particularly pronounced in dry years, in particular in the winter season, although the area of the aquifer impacted by dam operations remains almost unchanged. We thus observe that in Alpine catchments, surface water‐groundwater interaction is sensitive to the conditions determined by a specific hydrological year. We also investigate the influences of the river‐aquifer water fluxes and show that under dry conditions hydropeaking mainly affects their temporal dynamics. Our observations have significant consequences for predicting nutrient and temperature dynamics/regimes in river‐aquifer systems impacted by hydropower plant management.
    Description: Plain Language Summary: The operation of hydropower plants affects the water level in the downstream part of the river, which in turn can alter the groundwater level. In this work, we study an Alpine aquifer crossed by rivers differently impacted by hydropower production. We use statistical tools to analyze the interaction between the rivers and the groundwater, and observe that this interaction is sensitive to the conditions of the hydrological year, such as dry periods.
    Description: Key Points: Wavelet power spectrum and coherence analysis is used to study river‐aquifer interactions under dam operations in an Alpine catchment. The impact of reservoir operations on the aquifer is strongest under low flow conditions but the area impacted shows little variation. Under low flow conditions, dam operations considerably influence the frequency of the water exchange between rivers and aquifer.
    Description: Consejo Nacional de Ciencia y Tecnología http://dx.doi.org/10.13039/501100003141
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: Consejo Veracruzano de Investigación Científica y Desarrollo Tecnológico
    Description: https://doi.org/10.17632/97jchhz4s8.2
    Keywords: ddc:551 ; surface water‐groundwater interaction ; hydropower ; managed rivers ; groundwater modeling
    Language: English
    Type: doc-type:article
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  • 2
    ISSN: 1432-0649
    Keywords: 32 ; 35 ; 42.65 ; 32 ; 33 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 4 (1984), S. 172-180 
    ISSN: 0392-6737
    Keywords: Other topics in atomic spectra and interactions of atoms with photons ; Atomic and molecular measurement and techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si riportano i criteri costruttivi e le prestazioni di un tubo di scarica a catodo cavo da utilizzarsi in spettroscopia laser ad alta risoluzione. L'apparato è di semplice costruzione e rapidamente adattabile alle diverse esigenze. Sono quindi illustrate misure di spettroscopia optogalvanica senza effetto Doppler e si ottengono righe in larghezza omogenea per elementi anche refrattari ed altamente reattivi.
    Abstract: Резюме Приводятся конструкционные критерии и характеристики полой катодной трубки, разработанной специально для лазерной спектроскопии высокого разрешения. Аппарат прост по конструкции и легко демонтируется. Иллюстрируются измерения оптогальванической спектроскопиии без эффекта Доплера. Получаются узкие однородные ширины линий для огнеупорных и высокореактивных элементов.
    Notes: Summary We report the design criteria and performance characteristics of a hollow-cathode tube developed especially for high-resolution Doppler-free laser spectroscopy. It is simple to construct and is easily demountable. Narrow homogeneous line widths of refractory and highly reactive-element transitions have been observed by applying intermodulated detection scheme.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0003-2697
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 6423-6425 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We focus on YbCu4Ag and YbCu4Au and interpret the optical conductivity, measured from 2 meV to 6 eV at 10 and 300 K, in terms of self-consistent electronic structure calculations. Most of the relevant spectral structures are interpreted as interband transitions from hybridized f–d states below and at the Fermi level at high symmetry points. In particular, the large shoulder at about 2.4 and 2 eV in the spectrum of YbCu4Au and YbCu4Ag, respectively, can be interpreted in terms of a transition Γ4→Γ3 involving mostly d states. We also compare the electronic structure of YbCu4Ag with that of LuCu4Ag, to ascertain the influence of the f states on the conduction bands and carrier density at EF. This allows us to draw some qualitative considerations on the f-band hybridization in these compounds. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 7046-7052 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this article we discuss the betatron equations of motion for an e-beam propagating in a linearly polarized undulator. We include the magnetic field multipolar contributions and go beyond the usual harmonic approximation. The equations of motion are derived with the inclusion of anharmonic and transverse motion coupling terms. The single particle motion as well as the beam dynamics are carefully examined.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 92 (2002), S. 1816-1820 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: One-dimensional photonic crystals made of (Si/SiO2)m multilayers with m=2,...8 have been grown on SiO2 4-in. wafers by repeated polysilicon low-pressure chemical vapor deposition, oxidation, and wet etching steps. The poly-Si and SiO2 layers were about 220 and 660 nm thick, respectively, thus realizing λ/4 distributed Bragg reflectors. Spectroscopic ellipsometry in the 1.4–5 eV range was used to determine the dielectric function of poly-Si and the actual layer thicknesses, as well as to check the structural and compositional homogeneity of the structures. In order to measure the photonic crystal properties, specular reflectance and transmittance measurements were performed from 0.2 to 6 eV at different angles of incidence θ≤50° and for transverse electric and transverse magnetic polarizations. The stop-bands characteristic of Bragg reflector multilayers appear up to the fifth order and become more pronounced with increasing m, reaching almost complete rejection for m=4 periods. The experimental spectra were fitted by the transfer-matrix method, both versus θ and m. Moreover, the experimental stop bands of the finite multilayers matched the calculated photonic band gaps of an infinite one-dimensional photonic crystal very well. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 6438-6440 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Orthorhombic URhSi orders ferromagnetically below Tc=9.5 K, with an ordered magnetic moment μ=0.11μB per U atom and has a relatively enhanced value of the specific heat cp/T=186 mJ/mol K2. U-U atomic distances fall in a critical region around the Hill limit so that it is thought to be an itinerant magnet. Our present investigation includes: (i) preparation of high purity crystalline samples further analyzed by single crystal x-ray diffraction and magnetization measurements; (ii) band structure calculations performed with self-consistent full potential linearized Augmented plane wave method within the local density approximation; (iii) optical measurements at room and at low temperature over a large spectral range (2 meV–6 eV). As a result, the details of the crystal structure of URhSi have been refined with respect to previous measurements on powdered samples. The comparison of electronic structure calculations and optical results show: (a) a low mobility of free carriers and a large dielectric screening at the lowest frequencies, connected with excitation of f states hybridized with d states at the Fermi level; (b) smooth spectral features due to the huge number and density of states (the main contribution being due to occupied Rh d states). The whole amount of information obtained would suggest the presence of Kondo-like behavior in this compound, independently on the magnetic order. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 3084-3086 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Semi-insulating SI GaAs samples from a zone refined crystal were irradiated with high energy protons (24 GeV/c, fluences up to 1.64×1014 p/cm2). Optical spectra in transmittance and reflectance were accurately measured in the energy range of 0.6–1.4 eV to determine, through the absorption coefficient, the concentrations of both neutral and ionized EL2 defects as a function of the proton fluence. Both these concentrations have been shown to increase linearly with the proton fluence; this behavior well explains the remarkable decrease of the charge collection efficiency observed in proton irradiated GaAs detectors at doses associated with high luminosity beams at a new particle collider accelerator (e.g., the LHC at the CERN laboratory). © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Nuclear Instruments and Methods in Physics Research Section A: 333 (1993), S. 589-593 
    ISSN: 0168-9002
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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