574 research outputs found
Study of the structure of intermetalics from Fe - Al system after the hot rolling
This paper presents the results of structure analysis of Fe - Al alloys after hot rolling deformation. Microstructure analysis were performed before and after deformation using a scanning transmission electron microscopy (STEM) technique. The detailed quantities research of the structures was conducted using scanning electron microscopy (SEM) equipped with the gun with cold field emission and the detector of electron back scattering diffraction (EBSD)
Study of Deformation Effects in the Charged Particle Emission from 46Ti
The 46Ti compound nucleus, as populated by the fusion-evaporation reaction
27Al + 19F at the bombarding energy of 144 MeV, has been investigated by
charged particle spectroscopy using the multidetector array ICARE at the
VIVITRON tandem facility of the IReS (Strasbourg). The light charged particles
have been measured in coincidence with evaporation residues. The CACARIZO code,
a Monte Carlo implementation of the statistical-model code CASCADE, has been
used to calculate the spectral shapes of evaporated alpha-particles which are
compared with the experimental spectra. This comparison indicates the possible
signature of large deformations of the compound nucleus.Comment: 6 pages, 4 figures, Proceedings od the Zakopane 20004 Symposium, to
be published in Acta Phys. Pol. B36 (2005
Large Deformation Effects in the N = Z 44Ti Compound Nucleus
The N = Z 44Ti* nucleus has been populated in Fusion Evaporation process at
very high excitation energies and angular momenta using two entrance channels
with different mass-asymmetry. The deformation effects in the rapidly rotating
nuclei have been investigated through the energy distribution of the
alpha-particle combined to statistical-model calculations. In the case of
low-multiplicity events, the ratio between first particle emitted has been
measured and shows significant disagreement with the predictions of the
statistical-model. This may explain The large discrepancies observed in proton
energy spectra measured in previous experiments performed in the same mass
region.Comment: Proceeding of the 10th International Conference on Nuclear Reaction
Mechanisms, Varenna Italy, June 9-13 2003. 10 pages, 6 figures, 1 tabl
Application of Diamond Detectors in Tracking of Heavy Ion Slowed Down Radioactive Beams
Results of irradiation of thin Chemical Vapor Deposition (CVD) diamond detectors with low energy: p,α and 7Li beams are presented. Energy resolution: ÎE/E<1% of a single crystal detector was achieved. A coincident measurement with two diamond detectors showed time resolution of 100âps and efficiency above 70%. Despite a high beam flux reaching 109 particles/sâcm2 the tested detectors showed low dead-time and satisfactory radiation hardness. Perspectives of applying thin CVD diamond detectors in monitoring of a slowed down radioactive beam (RIB) are discussed.Spanish Ministry of Education and Science (MEC) FFPA2003-05958 and PA-2005-0446
Binary reaction decays from 24Mg+12C
Charged particle and gamma decays in 24Mg* are investigated for excitation
energies where quasimolecular resonances appear in 12C+12C collisions. Various
theoretical predictions for the occurence of superdeformed and hyperdeformed
bands associated with resonance structures with low spin are discussed within
the measured 24Mg* excitation energy region. The inverse kinematics reaction
24Mg+12C is studied at E_lab(24Mg) = 130 MeV, an energy which enables the
population of 24Mg states decaying into 12C+12C resonant break-up states.
Exclusive data were collected with the Binary Reaction Spectrometer in
coincidence with EUROBALL IV installed at the VIVITRON Tandem facility at
Strasbourg. Specific structures with large deformation were selectively
populated in binary reactions and their associated gamma decays studied.
Coincident events associated with inelastic and alpha-transfer channels have
been selected by choosing the excitation energy or the entry point via the
two-body Q-values. The analysis of the binary reaction channels is presented
with a particular emphasis on 24Mg-gamma, 20Ne-gamma and 16O-gamma
coincidences. New information (spin and branching ratios) is deduced on
high-energy states in 24Mg and 16O, respectively.Comment: 27 pages, 8 figures, 1 tabl
High-spin states and band terminations in v 49
High-spin states in 49 V have been studied through the 28 Si(28 Si, α3p) reaction using the EUROBALL Îł-ray detector array. The 49 V level scheme has been extended up to 13.1 MeV including 21 new states. Both negative and positive parity states have been interpreted in the framework of theShell Model. The 27/2â and the 31/2+ band termination states have been observed in agreement with theoretical predictions.Fil: Rodrigues Ferreira Maltez, Dario Pablo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. ComisiĂłn Nacional de EnergĂa AtĂłmica. Gerencia del Ărea de InvestigaciĂłn y Aplicaciones No Nucleares. Gerencia FĂsica (Centro AtĂłmico Constituyentes). Proyecto Tandar; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de FĂsica; ArgentinaFil: Hojman, Daniel Leonardo. ComisiĂłn Nacional de EnergĂa AtĂłmica. Gerencia del Ărea de InvestigaciĂłn y Aplicaciones No Nucleares. Gerencia FĂsica (Centro AtĂłmico Constituyentes). Proyecto Tandar; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Lenzi, Silvia M.. Istituto Nazionale Di Fisica Nucleare.; Italia. UniversitĂ di Padova; ItaliaFil: Cardona, Maria Angelica. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. ComisiĂłn Nacional de EnergĂa AtĂłmica. Gerencia del Ărea de InvestigaciĂłn y Aplicaciones No Nucleares. Gerencia FĂsica (Centro AtĂłmico Constituyentes). Proyecto Tandar; Argentina. Universidad Nacional de San MartĂn. Escuela de Ciencia y TecnologĂa; ArgentinaFil: Fernea, Enrico. UniversitĂ di Padova; Italia. Istituto Nazionale Di Fisica Nucleare.; ItaliaFil: Axiotis, M.. Istituto Nazionale Di Fisica Nucleare.; ItaliaFil: Beck, C.. UniversitĂ© de Strasbourg; Francia. Centre National de la Recherche Scientifique; FranciaFil: Bednarczyk, P.. Polish Academy of Sciences; ArgentinaFil: Bizzetti, P. G.. UniversitĂ di Padova; Italia. Istituto Nazionale Di Fisica Nucleare.; ItaliaFil: Bizzetti Sona, A. M.. UniversitĂ di Padova; Italia. Istituto Nazionale Di Fisica Nucleare.; ItaliaFil: Della Vedova, F.. UniversitĂ di Padova; Italia. Istituto Nazionale Di Fisica Nucleare.; ItaliaFil: Grebosz, J.. Polish Academy of Sciences; ArgentinaFil: Haas, F.. UniversitĂ© de Strasbourg; Francia. Centre National de la Recherche Scientifique; FranciaFil: Kmiecik, M.. Polish Academy of Sciences; ArgentinaFil: Maj, A.. Polish Academy of Sciences; ArgentinaFil: MÄczyĆski, W.. Polish Academy of Sciences; ArgentinaFil: Napoli, D. R.. Istituto Nazionale Di Fisica Nucleare.; ItaliaFil: Nespolo, M.. UniversitĂ di Padova; Italia. Istituto Nazionale Di Fisica Nucleare.; ItaliaFil: Papka, P.. UniversitĂ© de Strasbourg; Francia. Centre National de la Recherche Scientifique; FranciaFil: SĂĄnchez i Zafra, A.. UniversitĂ© de Strasbourg; Francia. Centre National de la Recherche Scientifique; FranciaFil: Styczen, J.. Polish Academy of Sciences; ArgentinaFil: Thummerer, S.. Alfred-Wegener-Institut, Helmholtz-Zentrum fĂŒr Polar- und Meeresforschung; AlemaniaFil: ZiÄbliĆski, M.. Polish Academy of Sciences; Argentin
Clusters in Light Nuclei
A great deal of research work has been undertaken in the alpha-clustering
study since the pioneering discovery, half a century ago, of 12C+12C molecular
resonances. Our knowledge of the field of the physics of nuclear molecules has
increased considerably and nuclear clustering remains one of the most fruitful
domains of nuclear physics, facing some of the greatest challenges and
opportunities in the years ahead. In this work, the occurence of "exotic"
shapes in light N=Z alpha-like nuclei is investigated. Various approaches of
superdeformed and hyperdeformed bands associated with quasimolecular resonant
structures are presented. Results on clustering aspects are also discussed for
light neutron-rich Oxygen isotopes.Comment: 12 pages, 5 figures. Invited Talk presented by C. Beck at the
Zakopane Conference on Nuclear Physics "Extremes of the Nuclear Landscape"
XLV in the series of Zakopane Schools of Physics - International Symposium -
Zakopane, Poland, August 30 - September 5, 2010.To be publihed in Acta
Physica Polonica B42 no 3, March 201
Search for Fingerprints of Tetrahedral Symmetry in
Theoretical predictions suggest the presence of tetrahedral symmetry as an
explanation for the vanishing intra-band E2-transitions at the bottom of the
odd-spin negative parity band in . The present study reports on
experiment performed to address this phenomenon. It allowed to determine the
intra-band E2 transitions and branching ratios B(E2)/B(E1) of two of the
negative-parity bands in .Comment: presented by Q.T. Doan at XLII Zakopane School of Physics: Breaking
Frontiers: Submicron Structures in Physics and Biology, May 2008. 5 pages,
minor corrections. To be published in the proceeding
cGMP-Elevating Compounds and Ischemic Conditioning Provide Cardioprotection Against Ischemia and Reperfusion Injury via Cardiomyocyte-Specific BK Channels.
BACKGROUND: The nitric oxide-sensitive guanylyl cyclase/cGMP-dependent protein kinase type I signaling pathway can afford protection against the ischemia/reperfusion injury that occurs during myocardial infarction. Reportedly, voltage and Ca2+-activated K+ channels of the BK type are stimulated by cGMP/cGMP-dependent protein kinase type I, and recent ex vivo studies implicated that increased BK activity favors the survival of the myocardium at ischemia/reperfusion. It remains unclear, however, whether the molecular events downstream of cGMP involve BK channels present in cardiomyocytes or in other cardiac cell types. METHODS: Gene-targeted mice with a cardiomyocyte- or smooth muscle cell-specific deletion of the BK (CMBK or SMBK knockouts) were subjected to the open-chest model of myocardial infarction. Infarct sizes of the conditional mutants were compared with litter-matched controls, global BK knockout, and wild-type mice. Cardiac damage was assessed after mechanical conditioning or pharmacological stimulation of the cGMP pathway and by using direct modulators of BK. Long-term outcome was studied with respect to heart functions and cardiac fibrosis in a chronic myocardial infarction model. RESULTS: Global BK knockouts and CMBK knockouts, in contrast with SMBK knockouts, exhibited significantly larger infarct sizes compared with their respective controls. Ablation of CMBK resulted in higher serum levels of cardiac troponin I and elevated amounts of reactive oxygen species, lower phosphorylated extracellular receptor kinase and phosphorylated AKT levels and an increase in myocardial apoptosis. Moreover, CMBK was required to allow beneficial effects of both nitric oxide-sensitive guanylyl cyclase activation and inhibition of the cGMP-degrading phosphodiesterase-5, ischemic preconditioning, and postconditioning regimens. To this end, after 4 weeks of reperfusion, fibrotic tissue increased and myocardial strain echocardiography was significantly compromised in CMBK-deficient mice. CONCLUSIONS: Lack of CMBK channels renders the heart more susceptible to ischemia/reperfusion injury, whereas the pathological events elicited by ischemia/reperfusion do not involve BK in vascular smooth muscle cells. BK seems to permit the protective effects triggered by cinaciguat, riociguat, and different phosphodiesterase-5 inhibitors and beneficial actions of ischemic preconditioning and ischemic postconditioning by a mechanism stemming primarily from cardiomyocytes. This study establishes mitochondrial CMBK channels as a promising target for limiting acute cardiac damage and adverse long-term events that occur after myocardial infarction
The PARIS cluster coupled to the BaFPro electronic module: data analysis from the NRF experiment at the ELBE facility
International audience; The first cluster of the constructed PARIS calorimeter was assembled and tested atthe ELBE facility at HZDR, Dresden, Germany. The experiment was aimed at the evaluationof the performance of each detector separately as well as the whole PARIS cluster with discrete-ray energies seen by the PARIS ranging up to 8.9 MeV. As the detectors use phoswichconfiguration, with 2'' x 2'' x 2'' LaBr3(Ce) crystal coupled to 2'' x 2'' x 6'' NaI(Tl) one, greatcare must be taken during the data analysis process to obtain the best possible values for energyresolution. Two algorithms for data transformation from matrices created with slow vs fastpulse shaping to energy spectra were tested from which one was chosen for further analysis. Analgorithm for adding back energies of -rays scattered inside the cluster was prepared, as well.Energy resolution for -rays in 2â8 MeV range was estimated and is presented in this paper
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