ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Theoretical study of magnetic properties of ammonia molecule in nonuniform magnetic field (1996)
    Springer
    Theoretical chemistry accounts 94 (1996), S. 155-176 
    Details
    ISSN: 1432-2234
    Keywords: Nonuniform magnetic field ; Magnetic multipoles ; Magnetic susceptibility ; Nuclear magnetic shielding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The interaction Hamiltonian within the Bloch gauge for the potentials of the electromagnetic field has been used to define magnetic multipole moment operators and operators for the magnetic field of electrons acting on the nuclei of a molecule in the presence of nonhomogeneous external magnetic field. Perturbation theory has been applied to evaluate the induced electronic moments and magnetic field at the nuclei. Multipole magnetic susceptibility and nuclear magnetic shielding tensors have been introduced to describe the contributions arising in nonuniform fields, and their origin dependence has been analyzed. Extended numerical tests on the ammonia molecule in a static, nonuniform magnetic field have been carried out, using the random-phase approximation within the framework of accurate Hartree-Fock zero-order wavefunctions, and allowing for both angular momentum and torque formalisms in the calculation of paramagnetic contributions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191646
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Theoretical study of magnetic properties of ammonia molecule in nonuniform magnetic field (1996)
    Springer
    Theoretica chimica acta 94 (1996), S. 155-176 
    Details
    ISSN: 0040-5744
    Keywords: Key words: Nonuniform magnetic field ; Magnetic multipoles ; Magnetic susceptibility ; Nuclear magnetic shielding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract.  The interaction Hamiltonian within the Bloch gauge for the potentials of the electromagnetic field has been used to define magnetic multipole moment operators and operators for the magnetic field of electrons acting on the nuclei of a molecule in the presence of nonhomogeneous external magnetic field. Perturbation theory has been applied to evaluate the induced electronic moments and magnetic field at the nuclei. Multipole magnetic susceptibility and nuclear magnetic shielding tensors have been introduced to describe the contributions arising in nonuniform fields, and their origin dependence has been analyzed. Extended numerical tests on the ammonia molecule in a static, nonuniform magnetic field have been carried out, using the random-phase approximation within the framework of accurate Hartree–Fock zero-order wavefunctions, and allowing for both angular momentum and torque formalisms in the calculation of paramagnetic contributions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191646
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    facet.materialart.
    Unknown
    Monitoring the mechanical stress of rocks through the electromagnetic emission produced by fracturing (2009)
    Elsevier Ltd
    Details
    Publication Date: 2017-04-04
    Description: The present note shows that the rock mass under stress and strain generates an ELF and VLF emission (EME) associated to the fracturing phenomena. On uniaxial stress this emission show two different modes. A disorderly succession of clustering EM pulses (DIS) is associated with the acoustics emission of fracturing. It is always manifested, culminates with the rupture and begins just before the 50% of the time necessary to break the rock with an constant increasing stress. In some cases, this phenomenon is preceded by a more orderly and homogeneous sequence of pulses EM (OIS), in this case not associated with the acoustics. The presence of water saturation influences the DIS EM emission. From our experimental observations results that the emission in the ELF and VLF bands is independent from the type of rock, which however condition the deformation history, and form the structural characteristics of the material. In a quarry have observed a similar phenomenon also on large stone masses under strain. These characteristics of the EME may be observed at great distances to monitor the preparation of an Earthquake; in fact radio waves as well as acoustic waves have their maximum propagation at the low frequency band.
    Description: Published
    Description: 940 - 945
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
    Description: JCR Journal
    Description: reserved
    Keywords: VLF electromagnetic emissions ; fracturing of rocks ; uniaxial compression ; seismic precursors ; earthquake ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 4
    facet.materialart.
    Unknown
    Possible electromagnetic earthquake precursors in two years of ELF-VLF monitoring in the atmosphere (2008)
    Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS, Trieste, Italy.
    Details
    Publication Date: 2017-04-04
    Description: In this study we show that ELF-VLF emissions, occurred during the fracturing of rocks in laboratory experiments and during rock extraction in a cave, have been recorded also before earthquakes by 3 ELF-VLF stations installed in the central Apennines. The electric field emission is composed by two types of signals which are related to the evolution of micro-fractures within the rocks. During two years of monitoring, from August 2003 to September 2005, we recorded three signals, which all have frequency band and characteristics similar to the signal recorded during the fracturing of rocks in the laboratory and during the extraction of rocks. All these signals occurred a few days before the occurrence of M ≥ 4.5 earthquakes in the surrounding region (100-300 km). May be EM precursors of the earthquakes ?
    Description: Published
    Description: 205-212
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: N/A or not JCR
    Description: reserved
    Keywords: earthquake ; precursor ; VLF ; electric ; Apennines ; rocks fracture ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 5
    facet.materialart.
    Unknown
    Rigorous time domain responses of polarizable media II (2006)
    Details
    Publication Date: 2019-11-04
    Description: We present and test in detail with synthetic data a method which may be used to retrieve the parameters describing the induced polarization properties of media which fit the generally accepted frequency dependent formula of Cole and Cole (1941) (CC model). We use time domain data and rigorous formulae obtained from the exact solution of the problem found in a previous note (Caputo, 1996). The observed data considered here are the theoretical responses of the medium to box inputs of given duration in media defined with different parameters; however, as is usually done, only the discharge data are used (Patella 〉F2〈et al.〉F1〈, 1987). The curve at the beginning of the discharge is studied in some detail. The method is successful in identifying the parameters when the data fit the CC model; if the medium is not exactly of the CC type the method may also help identify how the medium departs from the CC model. The Laplace Transform of the discharge for a box type input data is also given.
    Description: JCR Journal
    Description: open
    Keywords: induced polarization ; Cole-Cole model ; constitutive equations ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 2495233 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 6
    facet.materialart.
    Unknown
    Rigorous time domain responses of polarizable media (2006)
    Details
    Publication Date: 2019-11-04
    Description: The scope of this note is to study a model of induced polarization which fits the usually accepted frequency dependent formula of Cole and Cole, but is more general and allows the time domain observations to retrieve the parameters describing the induced polarization phenomena of the medium. By introducing the memory mechanisms, represented by derivatives of fractional order, in the relation between the electric flux density and the electric field and considering the fractional order differential equation which follows, I solve it with mathematically rigorous and closed formulae and compute the responses to a step function, a box, a set of positive boxes and a set of alternating positive and negative boxes. I also introduce a method which retrieves the parameters describing the medium when comparing the theoretical curves with the observed ones. The responses to these signals also allow to estimate the temporary alteration of the medium when repeated positive (negative) signals are input; the response increases (decreases) in amplitude when the signals are all positive (negative), it decreases when the signals are alternatively positive and negative in agreement with the known attitude of the medium to induced polarization.
    Description: JCR Journal
    Description: open
    Keywords: constitutive equations ; induction ; polarisation ; alternations ; Cole-Cole model ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 3189657 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 7
    facet.materialart.
    Unknown
    Diffusion with space memory modelled with distributed order space fractional differential equations (2006)
    INGV
    Details
    Publication Date: 2019-11-04
    Description: Distributed order fractional differential equations (Caputo, 1995, 2001; Bagley and Torvik, 2000a,b) were fi rst used in the time domain; they are here considered in the space domain and introduced in the constitutive equation of diffusion. The solution of the classic problems are obtained, with closed form formulae. In general, the Green functions act as low pass fi lters in the frequency domain. The major difference with the case when a single space fractional derivative is present in the constitutive equations of diffusion (Caputo and Plastino, 2002) is that the solutions found here are potentially more fl exible to represent more complex media (Caputo, 2001a). The difference between the space memory medium and that with the time memory is that the former is more fl exible to represent local phenomena while the latter is more fl exible to represent variations in space. Concerning the boundary value problem, the difference with the solution of the classic diffusion medium, in the case when a constant boundary pressure is assigned and in the medium the pressure is initially nil, is that one also needs to assign the fi rst order space derivative at the boundary.
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: distributed order ; fractional order ; differential equations ; constitutive equations ; diffusion ; space fractional derivative ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 116977 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...