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FALSO ANEURISMA DELL’ARTERIA SFENOPALATINA POST-OSTEOTOMIA DI LE FORT 1: UN CASO RECIDIVANTE
No full textProcopio di Cesarea, Santa Sofia di Costantinopoli. Un tempio di luce (De Aedificiis I 1, 1-78)
No full textLa parte del volume di mia pertinenza evidenzia gli aspetti peculiari del passo sulla basilica di Santa Sofia contenuto nel De Aedificiis di Procopio: l’interesse, raro per l’epoca, per gli aspetti tecnico-strutturali dell’edificio e per gli scienziati-architetti che lo progettarono; il punto di vista dell’osservatore che, in un processo di immedesimazione con l’autore, ci guida alla percezione dello spazio mutevole e complesso della basilica; l’intuizione– che ho inteso sviluppare – che Santa Sofia, in tutte e sue componenti, fu progettata come una gigantesca macchina di luce. Il libro è corredato da un ricco apparato illustrativo e da sette tavole ricostruttive, ideate da chi scrive espressamente per questo volume
[Nicolai Alemanni De Procopio et arcana eius historia indicium]
No full textTit. y autor tomados de prefacioTexto paralelo griego-latÞn de p. XIX-XXIII y p. 1-135Pie de imp. tomado de colofónSign.: a¬2-5, e¡3, i¡2, o¡4, A-R¡4, a-c¡4, d¬1, d¬3-4, e¡4, f¬2-3, g-i¡4, k¬1, k¬4, l-u¡4Error de pag., de p. 112 pasa a 115Texto a dos colContiene: Historia arcana / Procopius de Cesarea, p. 1-135Notas históricas a la Historia arcana de Procopio / Nicola s Alemanni, p. 1-14
Photoluminescent and crystal structure properties of the yellow and orange forms of [Re2(m-Cl)2(CO)6(m- 4,5-trimethyl-silyl-pyridazine]
No full textA series of neutral, dinuclear, luminescent rhenium(I) complexes suitable for phosphorescent organic light emitting devices (OLEDs) has been recently reported1,2. These compounds, of general formula [Re2(μ-Cl)2(CO)6(μ-1,2-diazine)], contain diazines bearing alkyl groups in one or in both the b positions. The complexes show intense green/yellow emissions in toluene solution and in the solid state and some of the complexes possess, in solution, high emission quantum yields (F 0.18-0.22 for the derivatives with disubstituted diazines). The excited state responsible for this emission can be confidentially described as a triplet metal-to-ligand charge transfer (3MLCT) level3. Following the DFT computational suggestions we have now synthetized a new complex of this family using the 4,5-bis(trimetylsilyl)-1,2-diazine ligand namely [Re2(m-Cl)2(CO)6(m- 4,5-trimethyl-silyl-pyridazine] (1, see Scheme). This complex has been completely carachterized in solution and it shows an emission maximum batochromically shifted respect to those of the analogous Re(I) compounds with alkyl-substituted diazine, with a lower quantum yield. Slow evaporation at room temperature of a CH2Cl2 solution containing (1) induces the concomitant formation of orange and yellow single crystals (Figure 1, top). X-ray crystal structure determinations performed at room temperature as well as at 100 K, show that they are two different polymorphs of the same compound. The emission spectra recorded on crystalline samples of the two polymorph (Figure 1, bottom) are hypsochromically shifted respect to the solution one and present higher quantum yields (lem = 537 nm and F = 0.30 for the yellow phase, lem = 575 nm and F = 0.50, for the orange one). References
(1) Mauro, M, Quartapelle Procopio, E., Sun,Y., Chien, C-H., Donghi, D., Panicati, M., Mercandelli, P., Mussini, P., D’Alfonso, G., De Cola, L. Adv. Func. Mat. 2009, in press
(2) Donghi, D., D’Alfonso, G., Mauro, M, Panigati, M., Mercandelli, P., Sironi, A., Mussini, P., D’Alfonso, L., Inorg. Chem. 2008, 47, 4243.
(3) Wrighton, M., Morse, D. L., J. Am. Chem. Soc., 1974, 96, 998
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
A numerical code for the solution of the Kompaneets equation in cosmological context
No full textContext. After fundamental ground-based,
balloon-born, and space experiments, and, in particular, after the
COBE/FIRAS results, confirming that only very small deviations from a
Planckian shape can be present in the CMB spectrum,
current and future CMB absolute temperature experiments
aim at discovering very small distortions
such as those associated with the cosmological reionization process
or that could be generated by different kinds of earlier processes.
Aims. Interpretation of future data calls for a continuous improvement in
the theoretical modeling of CMB spectrum.
In this work we describe the fundamental approach
and, in particular, the update to recent NAG versions
of a numerical code, KYPRIX,
specifically written to solve the Kompaneets
equation in a cosmological context. It was first implemented in the
years 1989-1991 to accurately compute
the CMB spectral distortions under general assumptions.
Methods. Specifically, we describe the structure and the main subdivisions of
the code and discuss the most relevant aspects of its technical
implementation. After a presentation of the
equation formalism and of the boundary conditions added
to the set of ordinary differential equations derived from
the original parabolic partial differential equation,
we provide details on the adopted space variable (i.e. dimensionless
frequency) and space discretization,
on time variables, on the output results, on the
accuracy parameters, and
on the used auxiliary integration routines. The problem with introducing
the time dependence of the ratio between electron and photon temperatures
and of the radiative Compton scattering term, both of them
introducing integral terms into the Kompaneets equation,
is addressed in the specific context of the recent NAG versions.
We describe the introduction of the cosmological constant
in the terms controlling the general expansion of the Universe
in agreement with the current concordance model,
of the relevant chemical abundances, and on the ionization history,
from recombination to cosmological reionization.
The global computational time, the impact of the various aspects of the
code on it, and the accuracy of the numerical integration are also
discussed.
Results. We present some of fundamental tests we carried out to
verify the accuracy, reliability, and performance
of the code.
We focus on some quantitative tests of energy
conservation and the time behavior of electron temperature.
A comparison of the results obtained with the update and the
original version of the code is presented for some representative cases.
Finally, we focus on some properties of the free-free distortions
relevant for the long wavelength region of the CMB spectrum.
Conclusions. All the tests demonstrate the reliability and versatility
of the new code version and its accuracy and
applicability to the scientific analysis of current CMB spectrum data and of much more precise measurements that will be
available in the future.
The recipes and tests
described in this work can also be useful for implementing accurate
numerical codes for other scientific purposes using
the same or similar numerical libraries or for verifying the validity
of different codes aimed at the same problem or similar ones
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Integration of large-size photovoltaic systems into the distribution grids: a P–Q chart approach to assess reactive support capability
No full textThis study addresses the issue of the control of both active (P) and reactive (Q) power flows injected by grid connected photovoltaic (PV) units participating in the provision of the reactive power compensation ancillary service. A model is derived allowing to define a sort of 'capability chart' for the PV unit, that is, the set of points in the P-Q plane which, at steady state, can be reached by properly operating the control system and without exceeding the physical limits of all the involved devices. To this aim, a basic algorithm is developed in the MATLAB environment relying on a simplified description of the system, which neglects the harmonics injected by the voltage source converter inverter used to connect the PV unit with a medium voltage radial distribution grid. The proposed model is used to evaluate all the possible working points in the P-Q chart; a proof of the stability of those points, using the well-known Lyapunov methods, is also annexed. Finally, simulations with the electromagnetic code PSCAD-EMTDC are performed in order to assess the validity of the approximate results and to improve the developed basic algorithm. © 2010 © The Institution of Engineering and Technology
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