233 pubblicazioni classificate nel seguente modo:

Further results on cerium fluoride crystals
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT
Autore/i: Anderson, S.; Auffray, E.; Aziz, T.; Baccaro, S.; Banerjee, S.; Bareyre, P.; Barone, L. E.; Borgia, B.; Boutet, D.; Burq, J. P.; Chemarin, M.; Chipaux, R.; Dafinei, I.; D'Atanasio, P.; De Notaristefani, F.; Dezillie, B.; Dujardin, C.; Dutta, S.; Faure, J. L.; Fay, J.; Ferrère, D.; Francescangeli, Oriano; Fuchs, B. A.; Ganguli, S. N.; Gillespie, G.; Goyot, M.; Gupta, S. K.; Gurtu, A.; Heck, J.; Hervé, A.; Hillemanns, H.; Holdener, F.; Ille, B.; Jönsson, L.; Kierstead, J.; Krenz, W.; Kway, W.; Le Goff, J. M.; Lebeau, M.; Lebrun, P.; Lecoq, P.; Lemoigne, Y.; Loomis, G.; Lubelsmeyer, K.; Madjar, N.; Majni, G.; El Mamouni, H.; Mangla, S.; Mares, J. A.; Martin, J. P.; Mattioli, M.; Mauger, G. J.; Mazumdar, K.; Mengucci, Paolo; Merlo, J. P.; Moine, B.; Nikl, N.; Pansart, J. P.; Pedrini, C.; Poinsignon, J.; Polak, K.; Raghavan, R.; Rebourgeard, P.; Rinaldi, Daniele; Rosa, J.; Rosowsky, A.; Sahuc, P.; Samsonov, V.; Sarkar, S.; Schegelski, V.; Schmitz, D.; Schneegans, M.; Seliverstov, D.; Stoll, S.; Sudhakar, K.; Svensson, A.; Tonwar, S. C.; Topa, V.; Vialle, J. P.; Vivargent, M.; Wallraff, W.; Weber, M. J.; Winter, N.; Woody, C.; Wuest, C. R.; Yanovski, V.
Classificazione: 1 Contributo su Rivista
Abstract: A systematic investigation of the properties of cerium fluoride monocrystals has been performed by the ''Crystal Clear'' collaboration in view of a possible use of such crystals for the construction of high precision electromagnetic calorimeters for the future generation of high luminosity accelerators. A large sample of different crystals grown by several producers has been studied. The spectroscopic characteristics, the transmission, luminescence aid excitation spectra and the decay time curves are analysed. The light yield of the different crystals is measured with photomultipliers and Si photodiodes and compared to reference standards like BGO and NaI(Tl). The radiation damage behaviour is then presented for gamma and neutron irradiations, at different doses and dose rates, including thermal and optical bleaching.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/51282

Gamma-ray focusing concentrators for astrophysical observations by crystal diffraction in Laue geometry
REVIEW OF SCIENTIFIC INSTRUMENTS
Autore/i: S., Melone; Francescangeli, Oriano; Caciuffo, ROBERTO GIOVANNI MARIA
Classificazione: 1 Contributo su Rivista
Abstract: The diffraction and optical properties of several crystal concentrator configurations which could be adopted in hard x-ray astrophysical observations are discussed and compared in terms of effective area, focusing characteristics, and overall dimensions. First, a concentrator consisting of a set of circular rings covered with asymmetric mosaic crystals in Laue geometry is considered; focusing is achieved by an appropriate choice of the geometrical parameters and the asymmetry angles. Specific effective areas larger than 600 cm2 can be obtained in the energy range 120-190 keV by using Si (422) Bragg reflections in a device with a diameter of 2.5 m and a focal length of 13.5 m. Afterwards, a spherical-zone crystal concentrator is analyzed where asymmetric Laue geometry leads to focusing. With a focal length of 8 m and Si (422) reflections, the mean effective area in the energy range 100-300 keV is about 6500 times larger than the focal spot while the separation power of the concentrator is of the order of 10 arcsec. Finally, a concentrator consisting of several coaxial focusing paraboloids is analyzed. The surfaces of the paraboloids are covered by mosaic crystal tiles with lattice planes disposed normally to the meridians. By using Ge crystals with a mosaic width of almost-equal-to 350 murad and assuming a focal length f = 10 m with a total aperture 2alpha = 16 deg, it is possible to obtain effective areas larger than 1000 cm2 for energies smaller than about 150 keV. On the other hand, the ratio between the mean effective area and the size of the focal spot in the energy range 200-500 keV is higher than 10 000.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/51118

Semi-flexible liquid crystalline polyesters based on twin di (p-oxybenzoyl) units X-ray study on smetic mesophase structures of C5Cn
LIQUID CRYSTALS
Autore/i: Francescangeli, Oriano; Albertini, Gianni; Bin, Yang; SANTE ANGELONI, A.; Laus, M.; Chiellini, E.; Galli, G.
Classificazione: 1 Contributo su Rivista
Abstract: An X-ray study is performed of oriented smectic mesophases of several polyesters consisting of two p-oxybenzoyl diads interconnected by a pentamethylene segment and a polymethylene segment of variable length. The X-ray diffraction patterns are very similar for all the samples and are constituted by one or more inner reflections, lying on the meridional line, and by two broad outer haloes split into two intense portions symmetrically placed above and below the equatorial line. The former reflections are attributed to the regular piling of the smectic layers; the latter are associated with the presence of rigid mesogenic groups that are tilted with respect to the layer normal, while the average chain axis lies perpendicular to the layer planes. Accordingly, the analysed smectic mesophases can be classified as unconventional smectic C. A structural model is proposed to account for the intensity profile of the X-ray pattern.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/50202

Transitions Metals Complexed to Ordered Mesophases. Synthesis, Mesomorphism, and X-ray and EPR Characterization of a Homologous Series of N-(4-Dodecyloxysalicylidene)-4'-alkylanilines Complexed to Oxovanadium(IV)
CHEMISTRY OF MATERIALS
Autore/i: M., Ghedini; S., Morrone; R., Bartolino; V., Formoso; Francescangeli, Oriano; B., Yang; D., Gatteschi; C., Zanchini
Editore: American Chemical Society:1155 Sixteenth Street Northwest:Washington, DC 20036:(800)227-5558, EMAIL: service@acs.org, INTERNET: http://www.pubs.acs.org, Fax: (614)447-3671
Classificazione: 1 Contributo su Rivista
Abstract: A number of mesogenic bis[4-(dodecyloxy)-N-(4'-R(n)-phenyl)salicylideneiminato]oxovanadium(IV) complexes (1-7, R(n) = CH3, C2H5, C3H7, C4H9, C6H13, OC6H13, C8H17, respectively) have been synthesized and characterized by polarizing microscope observations, DSC measurements, X-ray diffraction, and EPR spectroscopy. These compounds are thermally stable and to not decompose on melting. Complexes 1-5 show two different solid phases K1 and K2. In addition, 4 and 5 exhibit a liquid-crystalline smectic A phase (monotropic in 4 and enantiotropic in 5). On the other hand, 6 and 7 along with a single solid phase, display a smectic C (enantiotropic in 6 and monotropic in 7) and an enantiotropic smectic A phase. Variable-temperature EPR spectra are accounted for on the basis of paramagnetic metal ions experiencing different magnetic environments. For each mesophase, matching X-ray, and EPR data, the molecular packing mode is suggested. Comparing 1-7 with the homologous copper complexes, the contribution of the metallic center to the mesomorphic properties is discussed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/30014

Small-angle neutron scattering study of the microstructure in container glass in correlation with workability problems.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Autore/i: G., Albertini; Benedetti, A.; Carsughi, Flavio; DE MORAIS, M. M.; Francescangeli, Oriano; GEOTTI BIANCHINI, F.; Rustichelli, F.; Stefanon, M.
Editore: Elsevier BV:PO Box 211, 1000 AE Amsterdam Netherlands:011 31 20 4853757, 011 31 20 4853642, 011 31 20 4853641, EMAIL: nlinfo-f@elsevier.nl, INTERNET: http://www.elsevier.nl, Fax: 011 31 20 4853598
Classificazione: 1 Contributo su Rivista
Abstract: The small-angle neutron scattering (SANS) technique was used to verify the presence of inhomogeneities of the order of 10-100 nm which were suggested to influence the forming behaviour of container glass. Ternary soda lime glass and multicomponent container glass samples taken during periods of good and bad workability were investigated. The collected intensities show a marked SANS signal only in the case of heat treated ternary glasses, thus suggesting the presence of inhomogeneities between 1 nm and a few hundreds of nanometres in size. No inhomogeneities larger than 1 nm were found in the commercial glasses, regardless of their workability level. The presence of smaller inhomogeneities cannot be excluded.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/25032

Determination of molecular packing parameters in a IgG protein Langmuir Blodgett film
PHYSICA MEDICA
Autore/i: S., Dante; Mariani, Paolo; Francescangeli, Oriano; V., Erokhin; R., Kayushina
Editore: UK: Elsevier Pisa: Istituti Editoriali e Poligrafici Internazionali. Pisa Italy: Giardini Editori Stampatori
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/30074

A new class of compounds suited to study the torsional dynamics in the quantum regime: the calixarenes
CHEMICAL PHYSICS LETTERS
Autore/i: Caciuffo, ROBERTO GIOVANNI MARIA; G., Amoretti; F., Fillaux; Francescangeli, Oriano; S., Melone; M., Prager; F., Ugozzoli
Classificazione: 1 Contributo su Rivista
Abstract: Inelastic neutron scattering spectroscopy has been used to study the rotational dynamics of methyl groups in the p-tert butylcalix [4] arene(1:1)toluene complex. The neutron scattering function shows several lines between 0. 16 and 2.6 meV, and can be satisfactorily reproduced by the single-particle model for rotational tunneling only if the presence of inequivalent sites is assumed, in contrast with the crystallographic determinations. An approach consistent with the room-temperature crystal structure and giving a satisfactory description of the experimental results is obtained by the quantum sine-Gordon model, which describes the dynamics of infinite chains of coupled methyl groups.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/52742

Transition Metals Complexed to Ordered Mesophases. Synthesis, Characterization, and Mesomorphic Properties of New Potentially Ferroelectric Liquid-Crystals: Chiral p,p'-Dialkoxyazobenzenes and Their Cyclopalladated Dinuclear Complexes
CHEMISTRY OF MATERIALS
Autore/i: M., Ghedini; D., Pucci; E., Cesarotti; P., Antognazza; Francescangeli, Oriano; R., Bartolino
Editore: American Chemical Society:1155 Sixteenth Street Northwest:Washington, DC 20036:(800)227-5558, EMAIL: service@acs.org, INTERNET: http://www.pubs.acs.org, Fax: (614)447-3671
Classificazione: 1 Contributo su Rivista
Abstract: To prepare chiral metallo-mesogens with ferroelectric properties, new azobenzene compounds, HL(N)(n), bearing a chiral substituent have been synthesized. These ligands consist of two aliphatic chains of variable length, one of which contains a stereogenic center located in the para and para' positions of an azobenzene core. The chiral groups (R*O) are as follows: N = 1, (R)-(-)-menthol; N = 2, (S)-(-)-beta-citronellol, and N = 3, (R)-(-)-2-octanol; the aliphatic chains are linear n-alkoxy groups C(n)H2n+1O (n = 7, 10, 12, 14). Only the HL2(n) species display liquid-crystalline properties giving cholesteric or smectic A mesophases. The HL(N)(n) ligands react with [Pd(PhCN)2Cl2], to give the corresponding chloro-bridged dinuclear cyclopalladated products {Pd[L(N)(n)](mu-Cl)}2 as 1:1 mixtures of isomers arising from the nonselective attack of the palladium on the benzene ring bearing the chiral alkoxy group or on the benzene with the aliphatic alkoxy chain. The {Pd[L2(n)](mu-Cl)}2 compounds and the {Pd[L3(n)](mu-Cl)}2 (n = 10, 12,14) exhibit smectic mesophases (Sc* in {Pd[L2(7)](mu-Cl)}2, {Pd[L2(10)](mu-Cl)}2, {Pd[L3(10)](mu-Cl)}2, and {Pd[L3(14)](mu-Cl)}2, S(A) in {Pd[L2(12)](mu-Cl)}2, {Pd[L2(14)](mu-Cl)}2, {Pd[L3(12)]mu-Cl)}2). The Pd[LN(n)](mu-Cl)}2 compounds have been converted into the corresponding iodo analogues {Pd[LN(n)](mu-I)}2. The chloro complexes display a richer mesomorphism than the respective iodo compounds.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/30013

Dimensional Sensitivity of End-to-End Phase Difference in Ring Terminated Ramsey Cavities
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
Autore/i: A., DE MARCHI; Francescangeli, Oriano; G. P., Bava
Editore: IEEE / Institute of Electrical and Electronics Engineers Incorporated:445 Hoes Lane:Piscataway, NJ 08854:(800)701-4333, (732)981-0060, EMAIL: subscription-service@ieee.org, INTERNET: http://www.ieee.org, Fax: (732)981-9667
Classificazione: 1 Contributo su Rivista
Abstract: A transmission line analysis is reported of a long Ramsey cavity for a primary Cesium beam frequency standard, terminated at the extremities with two waveguide rings for distributed phase shift minimization. The purpose of this effort is to understand the effect of the rings on end-to-end phase shift. Contributions to the latter from asymmetries in the Ramsey cavity long arms, in the similarity of the rings, and in the two coupling junctions between rings and Ramsey cavity, are separately analyzed as a function of frequency. It is shown that this third asymmetry source may be a cause of phase shift instability because of its linear dependence on frequency. The slope of this sensitivity to operating frequency is reduced by almost an order of magnitude if the rings are designed to be antiresonant instead of resonant.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/30073

X-ray investigations on the cyclopalladated mesogen bis-{5-(1-nonyl)-2{[4'(1-nonyloxy)phenyl-2’-ato]}pyrimidine-N’,C2’]-μ-iodo}dipalladium(II)
LIQUID CRYSTALS
Autore/i: M., Ghedini; D., Pucci; R., Bartolino; Francescangeli, Oriano
Editore: Taylor & Francis Limited:Rankine Road, Basingstoke RG24 8PR United Kingdom:011 44 1256 813035, EMAIL: madeline.sims@tandf.co.uk, info@tandf.co.uk, INTERNET: http://www.tandf.co.uk, Fax: 011 44 1256 330245
Classificazione: 1 Contributo su Rivista
Abstract: The cyclopalladated complex [Pd(L3)(μ-I)]2 ([Pd(L3)(μ -I)]2 = bis-{5-(1-nonyl)-2{[4′(1-nonyloxy)phenyl-2′-ato]}pyrimidine-N′, C2′]-μ-iodo}dipaladium (II); C→105·1°C (C1)→128·1°C (SA)→202·5°C (I)) has been investigated by X-ray diffraction and the electron density profile along the director, in the smectic phase, determined. [Pd(L3(μ -I)]2 is a mesogenic species with a lateral-lateral fused molecular shape whose main features are: (i) the solid C1 phase when observed with a polarizing microscope gives a polygonal texture like a smectic A phase, and (ii) to describe properly the electron density profile along the director a model which takes into account a high electron density area (i.e. the four aromatic rings and the Pd2I2 fragment) extending perpendicular to the director is required.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29789

Transition metals complexed to ordered mesophases XIII. Synthesis and mesomorphic properties of potentially ferroelectric Schiff's bases palladium(II) complexes
LIQUID CRYSTALS
Autore/i: M., Ghedini; D., Pucci; E., Cesarotti; Francescangeli, Oriano; R., Bartolino
Editore: Taylor & Francis Limited:Rankine Road, Basingstoke RG24 8PR United Kingdom:011 44 1256 813035, EMAIL: madeline.sims@tandf.co.uk, info@tandf.co.uk, INTERNET: http://www.tandf.co.uk, Fax: 011 44 1256 330245
Classificazione: 1 Contributo su Rivista
Abstract: A series of N-[4'-(dodecyloxy)resorcylidene]-4-(RO*)-anilines (HL(n) n = 1, R*O = (-)-cis-myrtanyl; n = 2, R*O = (-)-menthyl; n = 3, R*O = S(-)-beta-citronellyl; n = 4, R*O = R-(-)-2-octyl) has been synthesized and the mesomorphic properties investigated. These ligands are able to chelate a metal atom; accordingly three different series of palladium complexes, [(Ln)Pd(Ln)], [(Ln)Pd(Azoxy-6)] and [(L3)Pd(Ph-Py(n))] (where Azoxy-6 and PhPy(n) are cyclopalladated 4,4'-dihexyloxyazoxybenzene and 5-substituted-244-substituted-phenyl)pyrimidine, respectively) have been prepared. The mesogenic HL3 and HL4 ligands exhibit a S(C)* phase, retained in [(L3)Pd(L3)], which changes to a cholesteric phase in [(L4)Pd(L4)] and becomes the more ordered S(H)* phase in the [(Ln)Pd(Azoxy-6)] (n = 3,4) derivatives. In contrast, in the [(L3)Pd(Ph-Py(n))] compounds the mesomorphic phase is a S(A) phase.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/30075

X-ray diffraction study of the smectic mesophase of some azobenzene-containing polyacrylates
LIQUID CRYSTALS
Autore/i: Francescangeli, Oriano; B., Yang; E., Chiellini; G., Galli; A. S., Angeloni; M., Laus
Editore: Taylor & Francis Limited:Rankine Road, Basingstoke RG24 8PR United Kingdom:011 44 1256 813035, EMAIL: madeline.sims@tandf.co.uk, info@tandf.co.uk, INTERNET: http://www.tandf.co.uk, Fax: 011 44 1256 330245
Classificazione: 1 Contributo su Rivista
Abstract: An X-ray study is performed on powder specimens and on stretched oriented fibres of two liquid crystalline polyacrylates containing the azobenzene mesogenic unit with either a 4'-n-pentyloxy (sample I-4) or 4'-n-hexyloxy (sample 1-5) substituent. The X-ray diffraction patterns of both samples showed the presence of a bilayer smectic C mesophase with the mesogneic groups tilted by an angle beta approximately 45-degrees (I-4) or beta approximately 38-degrees (I-5) with respect to the layer normal. The electron density profile rho(z) along the direction normal to the smectic layers was calculated by Fourier inversion and possible structural models of the smectic mesophase are discussed. A partial interdigitation of the terminal alkyloxy substituents appears to occur.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/30015

Polarized neutron diffraction study of the spin density distribution in an indolinonic nitroxide radical
PHYSICA. B, CONDENSED MATTER
Autore/i: Caciuffo, ROBERTO GIOVANNI MARIA; Francescangeli, Oriano; L., Greci; S., Melone; B., Gillon; G., Amoretti
Classificazione: 1 Contributo su Rivista
Abstract: The spin density distribution in the indolinonic nitroxide radical 1,2-dihydro-2-methyl-2-phenyl-3H-indole-3-oxo-1-oxyl has been determined by polarized neutron diffraction measurements. An analytical description of the spin density is obtained from the experimental data using the multipole expansion method. The results show that the unpaired electron is not confined to the N-0 group but is delocalised over the indolinic moiety.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/53223

An almost free methyl quantum rotor in p-tert-butylcalix [4] arene(1:1)toluene
PHYSICA. B, CONDENSED MATTER
Autore/i: Caciuffo, ROBERTO GIOVANNI MARIA; Francescangeli, Oriano; S., Melone; M., Prager; F., Ugozzoli; G. D., Andreetti; G., Amoretti; G., Coddens; H., Blank
Classificazione: 1 Contributo su Rivista
Abstract: The low temperature inelastic neutron scattering cross-section of p-tert-butylcalix[4]arene(1:1)toluene shows several bands between 0.16 and 2.55 meV, which are interpreted as due to transitions between tunneling-split librational states of the methyl group belonging to the toluene molecule. The rotational barrier provided by the host lattice is particularly small so that the system approaches the behaviour of a quantum-mechanically free rotor.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/53124

Transition Metals Complexed to Ordered Mesophases. Synthesis and Mesomorphic Properties of Cyclopalladated 4,4'-Bis(hexyloxy)azoxybenzene Complexed to N-(4-(Dodecyloxy)salicylidene)-4'-alkylanilines
CHEMISTRY OF MATERIALS
Autore/i: M., Ghedini; S., Morrone; Francescangeli, Oriano; R., Bartolino
Editore: American Chemical Society:1155 Sixteenth Street Northwest:Washington, DC 20036:(800)227-5558, EMAIL: service@acs.org, INTERNET: http://www.pubs.acs.org, Fax: (614)447-3671
Classificazione: 1 Contributo su Rivista
Abstract: New mononuclear cyclopalladated liquid-crystalline materials whose molecular structure consists of two different thermotropic ligands, namely, 4,4'-bis(hexyloxy)azoxybenzene and N-(4-(dodecyloxy)-salicylidene)-4'-n-CnH2n+1-aniline (n = 0, 1-4, 6, 8), connected by a palladium atom, have been prepared. These lateral-lateral fused mesogens, obtained as mixtures of N,N-cis and N,N-trans isomers (about 1:5 ratio), display good thermal stability and mesomorphic properties which depend on the length of the n-CnH2n+1 chain: monotropic nematic and/or smectic A (n = 0, 2, 4) and enantiotropic nematic (n = 1), nematic and smectic (n = 3), and smectic A (n = 6, 8). Contrarily, the clearing points for n = 1-4, 6, and 8 belong in a very narrow range: 143 +/- 3-degrees-C. Preliminary X-ray investigations in the solid and smectic phases show two different periodicities (nearly 45 and 28 angstrom for n = 0, 1-4; 25 and 29 angstrom for n = 6, 8) thus suggesting a peculiar molecular packing.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29787

Semiflexible Liquid-crystalline Polyesters based on Twin Di(p-oxybenzoyl) Units: Synthesis and Characterization
JOURNAL OF MATERIALS CHEMISTRY
Autore/i: E., Chiellini; G., Galli; M., Laus; A. S., Angeloni; Francescangeli, Oriano; B., Yang
Editore: Royal Society of Chemistry:Thomas Graham House, Science Park, Cambridge CB4 0WF United Kingdom:011 44 1223 432360, EMAIL: sales@rsc.org, INTERNET: http://www.rsc.org, http://www.chensoc.org, Fax: 011 44 1223 423429
Classificazione: 1 Contributo su Rivista
Abstract: A new series of thermotropic liquid-crystalline polyesters C5C(n) has been prepared, comprising two di(poxybenzoyl) units connected by a pentamethylene segment and a linear alkylene spacer of variable length. All the polymers present a disordered smectic mesophase while a nematic mesophase is also shown by polymer samples with relatively short alkylene segments (n = 5-8, 10). The nematic to isotropic transition temperatures fall with increasing n with a typical odd-even alternation. In complete contrast, a rising trend with a reversed odd-even alternation is observed for the smectic to nematic or isotropic transition temperatures. The polymer mesophases, once formed in the melt, can be frozen by cooling them to room temperature in a glassy state.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29783

Thermal and x-ray investigation of a new mesophasic semiflexible polyester
MOLECULAR CRYSTALS AND LIQUID CRYSTALS. LETTERS SECTION
Autore/i: E., Chiellini; G., Galli; B., Yang; Francescangeli, Oriano; S., Melone; A. S., Angeloni; M., Laus; D., Caretti
Editore: Gordon & Breach Science Publishers:PO Box 90, Reading RG1 8JL United Kingdom:011 44 118 9520303, 011 44 118 9560080, 011 44 181 9560080, EMAIL: philip.bott@gbmis.gbhap.com, INTERNET: http://www.gbhap.com/pubdate, Fax: 011 44 118 9568211
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29784

Accurate evaluation of electrical current excitation in brain cortex by magnetic field pulses
PHYSICA MEDICA
Autore/i: Cerri, G.; DE LEO, Roberto; Francescangeli, Oriano; Melone, S.
Editore: UK: Elsevier Pisa: Istituti Editoriali e Poligrafici Internazionali. Pisa Italy: Giardini Editori Stampatori
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29726

Characterization by γ-ray diffractometry of the mosaic structure of Bi4Ge3O12, Bi12GeO20 and BaF2 crystals
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT
Autore/i: F., Allegretti; Caciuffo, ROBERTO GIOVANNI MARIA; F., DE NOTARISTEFANI; F., Ferroni; Francescangeli, Oriano; G., Majni; M., Mattioli; Rinaldi, Daniele
Classificazione: 1 Contributo su Rivista
Abstract: γ-ray diffraction measurements have been performed to characterize the degree of perfection of several crystals of BGO and barium fluoride. In particular the mosaic structure and homogeneity of samples grown with different techniques have been determined.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/52555

Brain Cortex Current Distribution Induced by Low Frequency Electric and Magnetic Pulses
Italian Recent Advances in Applied Electromagnetics
Autore/i: Cerri, G.; DE LEO, Roberto; Francescangeli, Oriano; Melone, S.
Editore: Liguori
Luogo di pubblicazione: NAPOLI
Classificazione: 2 Contributo in Volume
Abstract: Invited Article
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/41266

Unpaired electron density in an indolinonic nitroxide radical as determined by polarized neutron diffraction
MOLECULAR PHYSICS
Autore/i: Caciuffo, ROBERTO GIOVANNI MARIA; Francescangeli, Oriano; L., Greci; S., Melone; B., Gillon; M., Brustolon; A. L., Maniero; G., Amoretti; P., Sgarabotto
Classificazione: 1 Contributo su Rivista
Abstract: The spin density distribution in the indolinonic nitroxide radical 1,2-dihydro-2-methyl-2-phenyl-3H-indole-3-oxo-1-oxyl has been determined by a multipole expansion analysis of polarized neutron diffraction data. A large spin delocalization from the NO group to the benzene ring of the indole nucleus has been found. The results are in agreement with those previously obtained from EPR and ENDOR spectroscopy and by INDO calculations. The experimental spin density distribution has been used to calculate the dipolar electron proton interaction tensors and the dipolar electron electron interaction between pairs of neighbour radical molecules. Comparisons with the hyperfine and fine structure tensors determined by ENDOR and EPR spectroscopy experiments are presented.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/53166

Blends of a Polyetherimide and a Liquid Crystalline Polymer: Fiber Orientation and Mechanical Properties
JOURNAL OF APPLIED POLYMER SCIENCE
Autore/i: C., Carfagna; E., Amendola; L., Nicolais; D., Acierno; Francescangeli, Oriano; B., Yang; F., Rustichelli
Editore: John Wiley & Sons Incorporated:Customer Service, 111 River Street:Hoboken, NJ 07030:(800)225-5945, (201)748-6000, EMAIL: societyinfo@wiley.com, INTERNET: http://www.wiley.com, Fax: (212)748-6551
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29727

Feasibility of End to End Phase Shift Correction from the Outside of Sealed Cesium Beam Tubes
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
Autore/i: A., DE MARCHI; Francescangeli, Oriano; G. P., Bava
Editore: IEEE / Institute of Electrical and Electronics Engineers Incorporated:445 Hoes Lane:Piscataway, NJ 08854:(800)701-4333, (732)981-0060, EMAIL: subscription-service@ieee.org, INTERNET: http://www.ieee.org, Fax: (732)981-9667
Classificazione: 1 Contributo su Rivista
Abstract: In the case of primary Cesium beam frequency standards realized in the laboratory the so-called "end-to-end" phase shift is usually taken into account on paper, and sometimes corrected by arm symmetrization, after it is carefully measured in beam reversal experiments, as part of the accuracy assessment procedure. It was suggested recently that hardware compensation might also be obtainable by introducing a suitable asymmetry in the symmetric port of the waveguide junction which feeds the resonator. In this way it may become feasible to correct end-to-end phase shift from the outside of commercially available tubes, which are sealed and therefore do not allow beam reversal measurements. The purpose of this paper is to show that such external compensation of end-to-end phase shift is possible for existing standards. Experimental results are reported for the effect of an asymmetry in the feeding port, which are obtained from the measured frequency difference of the standard upon reversal of the whole feeding structure. These results are compared to theoretical predictions based on electromagnetic calculations of the asymmetry introduced in the microwave structure by such an asymmetry in the feed. A discussion on how well the absolute size of the effect can be judged by observing the structure in reflection is also given. The relevance of this work toward accuracy statements on unidirectional beams is underlined.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29723

Dynamical diffraction of guided electromagnetic waves by two-dimensional periodic dielectric gratings
PHYSICAL REVIEW A
Autore/i: Francescangeli, Oriano; S., Melone; DE LEO, Roberto
Editore: American Institute of Physics:2 Huntington Quadrangle, Suite 1NO1:Melville, NY 11747:(800)344-6902, (631)576-2287, EMAIL: subs@aip.org, INTERNET: http://www.aip.org, Fax: (516)349-9704
Classificazione: 1 Contributo su Rivista
Abstract: The properties connected to the propagation of electromagnetic waves in rectangular waveguides loaded by periodic dielectric gratings have been treated by extending the theory of dynamical scattering by perfect atomic crystals. The theoretical formulation has been developed for the TE10 excitation of the periodic load, but it remains valid in the same form when a TE(n0) (n > 1) excitation takes place. The analysis was first developed for two-dimensional periodicities, and later the results were applied to one-dimensional periodicities without modifications to the formalism. The generalization of Bragg's law to guided propagation has been obtained, and the conditions and limits of applicability of the theory have been discussed. It has been shown that, when a small permittivity contrast between supporting and loaded material is present, the electromagnetic field can be approximated by either one or two waves only. The expressions of the electromagnetic field supported by the periodic medium and the dispersion relaion have been obtained. The diffraction pattern, the deviation from the generalized Bragg law, the width of the total reflection range, and the extinction length have been evaluated for a regular array of cylindrical holes on a polyethylene support. We have reported the results of an experiment carried out to verify the accuracy of the theory. The comparison between theoretical and experimental results has shown excellent agreement.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29725

Inelastic neutron scattering study of a ternary transition metal-metalloid glass
Proceedings of PHONONS 89
Autore/i: Caciuffo, ROBERTO GIOVANNI MARIA; Francescangeli, Oriano; S., Melone; E., Gering; J. B., Suck; M., Bonnet
Editore: Hunklinger, Ludwig, Weiss
Luogo di pubblicazione: HEIDELBERG
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/53486

Phase Transitions and Structural Studies of New Compounds Belonging to Homologous Series
NUOVO CIMENTO DELLA SOCIETÀ ITALIANA DI FISICA. D CONDENSED MATTER, ATOMIC, MOLECULAR AND CHEMICAL PHYSICS, BIOPHYSICS
Autore/i: E., Fanelli; G., Poeti; Albertini, Gianni; Francescangeli, Oriano; G., Torquati; Mariani, Paolo
Classificazione: 1 Contributo su Rivista
Abstract: Since few years, we have been studying the synthesis and the physical properties of homologous series with the following general structure: CH3-(CH2)m -CO-C6H4-N=N-C6H4-O-CO-(CH2)n -CH3, with n ranging from zero to sixteen. In this work we report the results of the diffractometric study of the liquid crystalline series 4-butanoyl-4′-n-alkanoyloxy azobenzenes (m=2) and 4-pentanoyl-4′-n-alkanoyloxy azobenzenes (m=3): in particular all the ordered smectic phases of the m=3 series have been identified and some structural parameters are discussed. Considering the smectic A phase, we have determined the layer thickness as a function of n for both the m=2 and m=3 series: the results have been compared with those of the homologous series with m=0 and m=1. In particular an appreciable decrease of the thickness increment due to a CH2 group and a corresponding increase of the thickness of aromatic sublayer were observed: these results are interpreted by means of a proposed model.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/51828

Theoretical reflectivities of bent crystal analyzers for fusion plasma diagnostics
REVIEW OF SCIENTIFIC INSTRUMENTS
Autore/i: Caciuffo, ROBERTO GIOVANNI MARIA; C., Ferrero; Francescangeli, Oriano; S., Melone
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/52401

X-Ray Investigations on a Homologous Series of N-(4-Alkoxysalicylidene)-4'-Alkyl-Anilines Complexed to Copper (II)
NUOVO CIMENTO DELLA SOCIETÀ ITALIANA DI FISICA. D CONDENSED MATTER, ATOMIC, MOLECULAR AND CHEMICAL PHYSICS, BIOPHYSICS
Autore/i: G., Torquati; Francescangeli, Oriano; M., Ghedini; S., Armentano; F. P., Nicoletta; R., Bartolino
Editore: Societa Italiana di Fisica:Via Saragozza 12 Subs Service, I 40123 Bologna Italy:011 39 051 331554, EMAIL: sif@sif.it, INTERNET: http://www.sif.it, Fax: 011 39 051 581340
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29511

An X-ray Investigation of Thermotropic Polymalonates Containing the Azobenzene Mesogen
MOLECULAR CRYSTALS AND LIQUID CRYSTALS INCORPORATING NONLINEAR OPTICS
Autore/i: G., Torquati; Francescangeli, Oriano; M., Laus; A. S., Angeloni; C., Carlini; D., Caretti; G., Galli; E., Chiellini
Editore: Gordon & Breach Science Publishers:PO Box 90, Reading RG1 8JL United Kingdom:011 44 118 9520303, 011 44 118 9560080, 011 44 181 9560080, EMAIL: philip.bott@gbmis.gbhap.com, INTERNET: http://www.gbhap.com/pubdate, Fax: 011 44 118 9568211
Classificazione: 1 Contributo su Rivista
Abstract: The structure of three main chain poly (α, ω-alkylene) monoalkylmalonate]s containing the azobenzene mesogen was investigated by X-ray diffraction. The mesogenic properties of the samples are compared with those of related side chain or combined polymeric systems.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29722

The generalised vibrational density of states of the metallic glass Fe40Ni40B20 determined by neutron inelastic scattering
JOURNAL OF PHYSICS. CONDENSED MATTER
Autore/i: R., Caciuffo; Francescangeli, Oriano; S., Melone; M., Stefanon; E., Gering; J. B., Suck; M., Bonnet; P., Allia; F., Vinai
Editore: IOP Publishing Limited:Dirac House, Temple Back, Bristol BS1 6BE United Kingdom:011 44 117 9297481, EMAIL: custserv@iop.org, INTERNET: http://www.iop.org, Fax: 011 44 117 9294318
Classificazione: 1 Contributo su Rivista
Abstract: The generalised vibrational density of states G( omega ) has been derived from inelastic neutron scattering measurements for the ternary transition metal-metalloid metallic glass Fe40Ni40B20. Two main energy bands are observed centred around 24 and 63 meV and separated by a shallow pseudo-gap near 50 MeV. The former band is mainly due to transition metal-transition metal interaction, the latter is associated to localised optical modes involving transition metal-boron bonds. Rather small differences, if any at all, have been observed for samples prepared by the metal spinning technique at different velocities of the rotating wheel. The neutron weighted G( omega ) have been used to calculate thermodynamic quantities like the temperature dependence of the specific heat and of the Debye temperature.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29508

Dynamical diffraction of microwaves by periodic dielectric media
PHYSICAL REVIEW A, GENERAL PHYSICS
Autore/i: Francescangeli, Oriano; S., Melone; DE LEO, Roberto
Editore: American Institute of Physics:2 Huntington Quadrangle, Suite 1NO1:Melville, NY 11747:(800)344-6902, (631)576-2287, EMAIL: subs@aip.org, INTERNET: http://www.aip.org, Fax: (516)349-9704
Classificazione: 1 Contributo su Rivista
Abstract: The properties of microwave diffraction by periodic dielectric media have been treated by extending the theory of dynamical scattering by perfect atomic crystals. The expressions of the form factor and of the structure factor have been obtained, and the conditions and limits of applicability of the two-wave approximation have been discussed. The diffraction pattern in Bragg geometry, the extinction length, the deviation from the Bragg law, and the width of the total reflection range have been evaluated for a two-dimensional periodic medium consisting of a regular array of cylindrical holes made on a polyethylene plane slab. We have reported the results of the experiment carried out to verify the accuracy of the theory. The comparison between theoretical and experimental results has shown good agreement.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29509

Mesomorphic Behaviour of Some 4-n-Pentanoyl-4'-n-Alkanoyloxy Azobenzenes (PPAPE). A New Series of Liquid-Crystal Compounds
NUOVO CIMENTO DELLA SOCIETÀ ITALIANA DI FISICA. D CONDENSED MATTER, ATOMIC, MOLECULAR AND CHEMICAL PHYSICS, BIOPHYSICS
Autore/i: E., Fanelli; G., Poeti; Francescangeli, Oriano; G., Torquati
Editore: Societa Italiana di Fisica:Via Saragozza 12 Subs Service, I 40123 Bologna Italy:011 39 051 331554, EMAIL: sif@sif.it, INTERNET: http://www.sif.it, Fax: 011 39 051 581340
Classificazione: 1 Contributo su Rivista
Abstract: In this paper we present the synthesis and the study of the homologous series {Mathematical expression} whith m=3 and n ranging from zero to sixteen. Transition temperatures, enthalpies and entropies have been determined making use of optical methods, differential scanning calorimetry and X-ray diffraction. Smectic and/or nematic phases have been observed for all the homologues with a complex polymorphism in some cases. A comparison with the series m=0, m=1 and m=2, precedently studied, is also reported.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29507

Microstrip disk antenna radiation into biological-like media
ALTA FREQUENZA
Autore/i: Cerri, G.; DE LEO, Roberto; Francescangeli, Oriano
Editore: Association Elettrotecnica Elettronic:AEI Uffic Center, Piaz Morandi 2, 20121 Milan Italy:011 39 02 77790223, EMAIL: soci@aei.it, Fax: 011 39 02 798817
Classificazione: 1 Contributo su Rivista
Abstract: The electromagnetic characteristics of microstrip disk antenna radiating into biological-like media are evaluated by use of the method of moments. In particular the distribution of electric field inside the biological-like body, the input admittance of the antenna and its working frequency as a function of the body dielectric characteristics are presented.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/29506