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Статті в журналах з теми "Fisica atomica e nucleare"
1
Sterbinski, M. J., F. Zappoli, C. Tamburlini, and J. P. Ognon. "Risonanza neutrinica digitale." Rivista di Neuroradiologia 7, no. 4 (August 1994): 627–35. http://dx.doi.org/10.1177/197140099400700409.
Повний текст джерелаАнотація:
Le indagini ormai tradizionali come la Tomografia Computerizzata (TC), la Tomografia ad Emissione di Positroni (PET) e la Risonanza Magnetica (RM), sono attualmente e drammaticamente superate dall'invenzione della Risonanza Neutrinica Digitale (RND), frutto di innovative ricerche nel campo della Cronoscopia e della Fisica Nucleare. La scoperta del neutrino neuropatico (VAINR), minuscola particella sub-atomica che disubbidisce sistematicamente a qualsiasi legge della Fisica tradizionale, ha rivoluzionato le precedenti conoscenze sull'argomento, rendendo in parte possibile uno dei più antichi desideri dell'uomo: «percorrere il tempo nelle due direzioni» anche se solo alla ricerca di patologia del Sistema Nervoso Centrale. Questo lavoro si propone di divulgare i più recenti sviluppi di questa straordinaria metodica ed ipotizza inoltre la nascita di una nuova disciplina neuroradiologica: oltre alla diagnostica, terapeutica e pediatrica anche la Neuroradiologia Cronobiologica.
2
LUCHERINI, VINCENZO. "THE FINUDA EXPERIMENT ON DAΦNE". International Journal of Modern Physics A 26, № 03n04 (10 лютого 2011): 420–25. http://dx.doi.org/10.1142/s0217751x11051767.
Повний текст джерелаАнотація:
FINUDA (FIsica NUcleare a DAɸne) is a spectrometer built to study the interactions of stopped K - on nuclei, with emphasis on spectroscopy and decay of Λ-hypernuclei. Due to the nice performances of the apparatus and its ability to reconstruct secondary vertices, it proved suited to study also final states with several particles (including neutron), hence greatly enlarging the physical topics that could be addressed.
3
Andrighetto, A., F. Borgna, M. Ballan, S. Corradetti, E. Vettorato, A. Monetti, M. Rossignoli, et al. "The ISOLPHARM project: A New ISOL production method of high specific activity beta-emitting radionuclides as radiopharmaceutical precursors." International Journal of Modern Physics: Conference Series 48 (January 2018): 1860103. http://dx.doi.org/10.1142/s2010194518601035.
Повний текст джерелаАнотація:
The ISOLPHARM project explores the feasibility of exploiting an innovative technology to produce extremely high specific activity beta-emitting radionuclides as radiopharmaceutical precursors. This technique is expected to produce radiopharmaceuticals that are virtually mainly impossible to obtain in standard production facilities, at lower cost and with less environmental impact than traditional techniques. The groundbreaking ISOLPHARM method investigated in this project has been granted an international patent (INFN). As a component of the SPES (Selective Production of Exotic Species) project at the Istituto Nazionale di Fisica Nucleare–Laboratori Nazionali di Legnaro (INFN–LNL), a new facility will produce radioactive ion beams of neutron-rich nuclei with high purity and a mass range of 80–160 amu. The radioactive isotopes will result from nuclear reactions induced by accelerating 40 MeV protons in a cyclotron to collide on a target of UC[Formula: see text]. The uranium in the target material will be [Formula: see text]U, yielding radioactive isotopes that belong to elements with an atomic number between 28 and 57. Isotope separation on line (ISOL) is adopted in the ISOLPHARM project to obtain pure isobaric beams for radiopharmaceutical applications, with no isotopic contaminations in the beam or subsequent trapping substrate. Isobaric contaminations may potentially affect radiochemical and radionuclide purity, but proper methods to separate chemically different elements can be developed.
4
Parsi, Vittorio Emanuele. "La bomba e noi." EDUCAZIONE SENTIMENTALE, no. 14 (September 2010): 34–44. http://dx.doi.org/10.3280/eds2010-014003.
Повний текст джерелаАнотація:
Durante la Guerra Fredda le armi nucleari hanno segnato il panorama delle Relazioni Internazionali rendendo il conflitto tra le superpotenze di fatto improbabile. Sulla scia di tale esperienza, nella memoria attuale l'effetto stabilizzante della bomba atomica sembra quasi occultare gli aspetti piů nefasti e tuttora incompresi del delicato equilibrio del terrore. Tuttavia, la fine del bipolarismo e la frammentazione del sistema internazionale hanno minato il potenziale di stabilizzazione dell'ordigno nucleare, rendendolo al contrario un pericoloso fattore di disordine. Le recenti ambizioni nucleari (piů o meno coronate da successo) di Stati quali Pakistan, Corea del Nord e Iran impongono quindi un ripensamento non solo della teoria della deterrenza, ma dell'intera architettura istituzionale volta a prevenire la proliferazione nucleare.
5
Lucherini, V. "THE FINUDA EXPERIMENT AT DAɸNE". International Journal of Modern Physics E 19, № 12 (грудень 2010): 2514–22. http://dx.doi.org/10.1142/s0218301310017022.
Повний текст джерелаАнотація:
The FINUDA (FIsica NUcleare a DAɸNE) experiment was built in order to study the interactions of stopped K - on nuclei, with emphasis on Hypernuclear spectroscopy and Hypernuclei decays. Due to the nice performances of the spectrometer, it proved also suited to study, more generally, final states with several particles and able to recostruct secondary vertices, hence greatly enlarging the physical topics that could be addressed.
6
Soukeras, V., F. Cappuzzello, M. Cavallaro, D. Carbone, A. Hacisalihoglu, M. Fisichella, C. Agodi, et al. "Study of the 4He(4He,4He)4He* inelastic scattering at the MAGNEX facility." EPJ Web of Conferences 252 (2021): 04007. http://dx.doi.org/10.1051/epjconf/202125204007.
Повний текст джерелаАнотація:
The 4He(4He,4He)4He* inelastic scattering was revisited in a new coincidence measurement at the MAGNEX facility of Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali del Sud. The 4He + 4He → 4He + 4He* → 4He + 3H + 1H and 4He + 4He → 4He + 4He* → 4He + 3He + n reactions were measured simultaneously by detecting the 4He particles at the MAGNEX magnetic spectrometer in coincidence with the 3H and 3He at the OSCAR silicon telescope. The main concept of the experiment is described and the data reduction strategy is reported.
7
Badalà, A., M. La Cognata, R. Nania, M. Osipenko, S. Piantelli, R. Turrisi, L. Barion, et al. "Trends in particle and nuclei identification techniques in nuclear physics experiments." La Rivista del Nuovo Cimento 45, no. 3 (March 2022): 189–277. http://dx.doi.org/10.1007/s40766-021-00028-5.
Повний текст джерелаАнотація:
AbstractParticle identification techniques are fundamental tools in nuclear physics experiments. Discriminating particles or nuclei produced in nuclear interactions allows to better understand the underlying physics mechanisms. The energy interval of these reactions is very broad, from sub-eV up to TeV. For this reason, many different identification approaches have been developed, often combining two or more observables. This paper reviews several of these techniques with emphasis on the expertise gained within the current nuclear physics scientific program of the Italian Istituto Nazionale di Fisica Nucleare (INFN).
8
Sgouros, O., V. Soukeras, A. Pakou, F. Cappuzzello, L. Acosta, C. Agodi, N. Alamanos, et al. "Study of continuum excitation by light weakly bound projectiles on proton target." EPJ Web of Conferences 223 (2019): 01058. http://dx.doi.org/10.1051/epjconf/201922301058.
Повний текст джерелаАнотація:
Elastic scattering and breakup angular distribution measurements for the systems 6,7Li + p were performed at the MAGNEX facility of the Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali del Sud (INFN-LNS) in Catania, in the energy range of (2.3–5.4)AMeV. The breakup channel was identified and quantified adopting the algorithm MULTIP.Within this algorithm which is a Monte Carlo simulation code, the history of the breakup fragments can be tagged from the rest frame of the decay nucleus itself to the laboratory frame. Angular distribution data of both elastic scattering and breakup were analyzed under the same theoretical model and the influence of continuum on the elastic channel was investigated.
9
Niccolucci, Franco. "4CH: un progetto per sviluppare le applicazioni e le competenze digitali per la gestione del patrimonio culturale." DigItalia 17, no. 1 (June 2022): 161–67. http://dx.doi.org/10.36181/digitalia-00045.
Повний текст джерелаАнотація:
L’articolo descrive il progetto europeo 4CH – Centro di Competenza per la conservazione del patrimonio culturale. Il progetto, coordinato da INFN – Istituto Nazionale di Fisica Nucleare attraverso la sua rete di laboratori CHNet, realizzerà un Centro che metterà a disposizione di operatori e istituzioni tecnologie scientifiche e digitali avanzate per la conservazione e il restauro, in particolare l’uso di modelli 3D. Le metodologie e tecnologie saranno documentate e rese disponibili, insieme a standard e buone pratiche, su una base digitale della conoscenza. Saranno inoltre creati strumenti di formazione e di aggiornamento. Il Centro di Competenza europeo si articolerà attraverso una rete di Centri nazionali, e insieme contribuiranno a realizzare la trasformazione digitale del settore dei beni culturali.
10
Miliucci, Marco, Massimiliano Bazzi, Damir Bosnar, Mario Bragadireanu, Marco Carminati, Michael Cargnelli, Alberto Clozza та ін. "Silicon Drift Detectors’ Spectroscopic Response during the SIDDHARTA-2 Kaonic Helium Run at the DAΦNE Collider". Condensed Matter 6, № 4 (25 листопада 2021): 47. http://dx.doi.org/10.3390/condmat6040047.
Повний текст джерелаАнотація:
A large-area silicon drift detectors (SDDs) system has been developed by the SIDDHARTA-2 collaboration for high precision light kaonic atom X-ray spectroscopy at the DAΦNE collider of Istituto Nazionale di Fisica Nucleare—Laboratori Nazionali di Frascati. The SDDs’ geometry and electric field configuration, combined with their read-out electronics, make these devices suitable for performing high precision light kaonic atom spectroscopy measurements in the background of the DAΦNE collider. This work presents the spectroscopic response of the SDDs system during the first exotic atoms run of SIDDHARTA-2 with kaonic helium, a preliminary to the kaonic deuterium data taking campaign. The SIDDHARTA-2 spectroscopic system has good energy resolution and a 2 μs timing window which rejects the asynchronous events, scaling the background by a factor of 10−5. The results obtained for the first exotic atoms run of SIDDHARTA-2 prove this system to be ready to perform the challenging kaonic deuterium measurement.
Дисертації з теми "Fisica atomica e nucleare"
1
Di, Meco Lorenzo. "Teoria variazionale con alcune applicazioni in fisica atomica e nucleare." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18374/.
Повний текст джерелаАнотація:
Il metodo variazionale è uno schema computazionale che permette il calcolo approssimato dell’energia e della funzione d’onda dello stato fondamentale di una grande varietà di
sistemi quantistici che compaiono in fisica molecolare, atomica e nucleare. In questa tesi vengono illustrati il metodo variazionale e le sue modalità di implementazione. Vengono poi descritte diverse applicazioni: lo studio di alcuni sistemi atomici, quali l’atomo di idrogeno, di elio e l’atomo muonico, e del deutone, per ricavarne un’approssimazione dell’autovalore di energia dello stato fondamentale; si studia infine l’interazione tra nucleoni per stimare il raggio d’azione del potenziale di Yukawa e le condizioni per l’esistenza di stati legati.
2
D'Emilio, Gianluca. "Applicazioni del metodo variazionale ad alcuni problemi di fisica atomica e nucleare." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15411/.
Повний текст джерелаАнотація:
Utilizzando il metodo variazionale si studiano alcuni sistemi
con l’obiettivo di approssimare l’energia del loro stato fondamentale. I casi trattati in questa tesi vertono su problemi di
natura atomica, quali la descrizione degli atomi di idrogeno,
elio e dell’atomo muonico, e su problemi di carattere nucleare,
quali la stima dell’ampiezza del potenziale di Yukawa e la
descrizione del deutone.
3
GONCALVES, JOSEMARY A. C. "Pesquisas propriedades e aplicacoes de detectores de faisca em problemas de fisica nuclear de energia atomica." reponame:Repositório Institucional do IPEN, 1993. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10321.
Повний текст джерелаАнотація:
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
4
Brenna, M. "A MICROSCOPIC PARTICLE-VIBRATION COUPLING APPROACH FOR ATOMIC NUCLEI. GIANT RESONANCE PROPERTIES ANDTHE RENORMALIZATION OF THE E FFECTIVE INTERACTION." Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/233251.
Повний текст джерелаАнотація:
The atomic nucleus can be described, to a first approximation, as composed by independent particles, moving in an average potential created by all of them. Self-consistent mean-field (SCMF) methods are based on this basic idea, and they are known to produce overall successful results for ground state and excited state properties, such as masses, radii, deformations and giant resonance energies. In the first part of this work, we present our theoretical predictions on two different excitations: the pygmy dipole resonance and the isovector quadrupole resonance. The calculations are performed within a fully self-consistent framework, in which the Skyrme zero-range effective interaction is used.
However, SCMF approaches present well-known limitations which require the inclusion of further correlations coming e.g. from the interweaving between single-particle and collective degrees of freedom (particle-vibration coupling – PVC). In the second part of this work, we report on the application of a self-consistent model based on the PVC idea in the Skyrme framework to inclusive (namely, the strength function of giant resonances) and exclusive (the gamma-decay width of giant resonances) observables.
The main limitation of our beyond mean-field model is the use of an effective interaction fitted at mean-field level to some selected experimental data. Therefore, when these interactions are used in beyond mean-field theories the parameters of the interactions need to be determined at the desired level of approximation. Moreover, due to the zero range character of the employed interaction, divergences arise. In the last and most innovative part of this thesis, we develop a possible way to cure the divergences, paving the way to the possibility of designing an effective interaction fitted at PVC level.
5
Ferraz, Jorge Ronan. "Efeito de absorção em espalhamento de elétrons por molécula de formaldeido." Universidade Federal de São Carlos, 2011. https://repositorio.ufscar.br/handle/ufscar/5035.
Повний текст джерелаАнотація:
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Previous issue date: 2011-10-02Financiadora de Estudos e Projetos
This master's project's main objective is to study the effects of absorption in the elastic scattering of electrons by molecules of formaldehyde (CH2O). We calculated differential cross sections (SCD), integral cross sections (SCI) and cross sections for momentum transfer (SCTM) for elastic scattering and total cross sections (SCT) and cross sections of total absorption (SCAT) for incident electron energies in the range 0.2 to 500 eV. The absorption effects were included using a complex optical potential to describe electron-molecule interaction. The imaginary part of this potential corresponds to an absorption potential. In our calculations the potential to absorb a potential model used was proposed by our group in 2007 and known in literature as SQFSM (scaled quasi-free scattering model). This optical potential was used in the numerical solution of the Lippmann-Schwinger equation to obtain the wave functions of the continuum describing the incident and scattered electrons, which are used to calculate scattering amplitudes and the corresponding cross sections. The numerical solution was obtained by the technique of Padé approximants of the combined use of the method of partial wave expansion. The strong permanent electric dipole of the target leads to a well-known difficulty of convergence of these expansions, outlined in our study by using the technique of complementation using the First Born approximation. Our results highlight the importance of including absorption effects in the study of elastic e--CH2O collisions. In general, such effects are associated with loss of elastically scattered electrons flow due to the opening of inelastic processes that compete with the elastic process. So they arise whenever the incident electron energy is sufficient to excite electronically the target, but its relevance to the elastic process depends on the target under study. In the case of formaldehyde molecule, the energy for the first excited state (ã3A2) is 3.45 eV and the first ionization potential is 10.88 eV. Despite these values, our calculations show that the inclusion of the absorption potential for does not significantly alter the values of the various cross section to energies up to 15 eV, but from this value leads to a reduction in the values of SCD, such reduction grows with energy until the range between 100 and 200 eV, which reaches about 50% and decreases for energies above them. viii Our results were compared with several theoretical and experimental results available in literature. Unfortunately the only published experimental reports measurements of SCD in the range 0.4 to 2.6 eV. On the other hand, there are several theoretical studiies published that report cross sections for energies up to 80 eV. In general our results agree well with literature data.
Este projeto de mestrado tem como objetivo principal estudar os efeitos de absorção no espalhamento elástico de elétrons por moléculas de formaldeído (CH2O). Foram calculadas seções de choque diferenciais (SCD), seções de choque integrais (SCI) e seções de choque de transferência de momento (SCTM) para o espalhamento elástico, bem como seções de choque total (SCT) e seções de choque de absorção total (SCAT) para energias do elétron incidente no intervalo de 0,2 a 500 eV. Os efeitos de absorção foram incluídos com o uso de um potencial óptico complexo para descrever a interação elétron-molécula. A parte imaginária deste potencial corresponde a um potencial de absorção. Em nossos cálculos o potencial de absorção utilizado foi um potencial modelo proposto pelo nosso grupo em 2007 e conhecido na literatura como SQFSM (do inglês scaled quasi-free scattering model). Este potencial óptico foi utilizado na solução numérica da equação de Lippmann- Schwinger para a obtenção das funções de onda do contínuo que descrevem os elétrons incidente e espalhado, as quais são usadas para calcular as amplitudes de espalhamento e as correspondentes seções de choque. A solução numérica foi obtida pela técnica dos aproximantes de Padé conjugada à utilização do método de expansão em ondas parciais. O forte dipolo elétrico permanente do alvo leva a uma conhecida dificuldade de convergência destas expansões, contornada em nosso estudo pela utilização da técnica de complementação utilizando a Primeira Aproximação de Born. Nossos resultados evidenciam a importância da inclusão dos efeitos de absorção no estudo das colisões elásticas e--CH2O. De um modo geral, tais efeitos são associados à perda de fluxo de elétrons espalhados elasticamente, devido à abertura de processos inelásticos que competem com o processo elástico. Assim eles surgem sempre que a energia do elétron incidente for suficiente para excitar eletronicamente o alvo, mas a sua relevância para o processo elástico depende do alvo em estudo. No caso da molécula de formaldeído a energia de excitação para o primeiro estado excitado (ã3A2) é de 3,45 eV e o primeiro potencial de ionização é de 10.88 eV. Apesar destes valores, nossos cálculos mostram que a inclusão do potencial de absorção não altera significativamente os valores das diversas secções de choque para energias até cerca de 15 eV, mas a partir deste valor, leva a uma redução dos valores de SCD, redução esta que cresce com a energia até a faixa entre 100 e 200 eV, em que chega a cerca de 50%, e é decrescente para energias acima destas. vi Nossos resultados foram comparados com vários resultados teóricos e experimentais disponíveis na literatura. Infelizmente o único trabalho experimental publicado se refere a medidas de SCD na faixa de 0,4 a 2,6 eV. Por outro lado, existem vários trabalhos teóricos publicados que reportam seções de choque para energias até 80 eV. Em geral nossos resultados concordam bem com os dados da literatura.
6
Argenti, Luca. "The B-spline K-matrix Method in Atomic Physics." Doctoral thesis, Scuola Normale Superiore, 2009. http://hdl.handle.net/11384/85858.
Повний текст джерелаАнотація:
In the course of this thesis the B-spline K-matrix method, a theoretical technique
capable of reproducing the single ionization continuum of atoms, was developed.
Two systems were addressed in particular: helium and boron, as representatives
of two- and three-active-electron atoms.
Some of the findings presented here resulted in original cont
ributions to the scientific literature. Total and partial photoionization cros
s sections and asymmetry parameters of the fundamental helium state were examined up
to the sixth ionization threshold, yielding the first
ab initio reproduction of the first intruder state
effects below N=4 threshold, the first reproduction of dipole
asymmetry parameters below N=6 threshold and of nondipole anisotropy param
eter γ below N=2 threshold.
Most of the material presented here relies on the multiple ba
sis implementation of the B-spline K-matrix method which allows the reprod
uction of almost arbitrarily excited metastable satellites below a prescri
bed threshold. The new technique, when used to investigate helium triplet states,
yielded the most accurate and extensive existing characterization of triplet me
tastable states up to the fifth ionization threshold. Within more than 1700 natural and unnatural S, P and D doubly excited states, eleven intruder states were discov
ered, entirely unknown before.
At least two experimental groups, at ELETTRA in Trieste and at BESSY II in Berlin, are recently tackling the problem of measuring the m
etastable 2^3S helium photoionization cross section. We therefore undertook a parallel theoretical investigation of the photoionization process of both the fundame
ntal and the excited ^3S helium states. The latter prelude to the future investigati
on of the radiative decay of doubly excited states and already revealed interesting p
eculiar features.
To this purpose, we devised an extension of the K-matrix method to treat the
atom-radiation interaction non perturbatively.
A general three electron package has been developed and appl
ied to study boron resonances. Specific formulas were derived to obtain arbitrary tensorial one-particle and scalar two-particle matrix elements between three electron states on non-orthogonal basis as required for an efficient exploitation of B-splines.
A detailed study of the B-spline effective completeness led to a general result
which assure that B-spline based methods are well conditioned for a large class of
knot grids.
7
Reis, Tatiana Russo dos. "Oxidação de esculturas de aço patinável pertencentes ao acervo da Pinacoteca de São Paulo." Universidade Presbiteriana Mackenzie, 2018. http://tede.mackenzie.br/jspui/handle/tede/3611.
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The Pinacoteca de São Paulo has a collection of artworks by Brazilian artists dating from the 17th century to the present. An important part of the collection consists of weathering steel sculptures displayed in different internal and external spaces. Besides offering good resistance to corrosion, weathering steels are extensively used in outdoor sculptures and built structures, due to its attractive appearance and self-regenerating capacity. By identifying the materials that compose an artwork and the phenomena that might occur on a given surface, it is possible to carry out preventive conservation actions in the short, medium and long terms. Initially, a visual analysis was performed on each individual work, as well as an accurate identification of the metals with the aid of handheld X-ray fluorescence spectrometry (XRF). Afterwards samples were collected for scanning electron microscopy (SEM) and X-ray diffraction analysis, which identified different oxides formed on their surfaces. In order to obtain more precise results regarding the elements that compose the works, a new process of identification in situ was carried out using X-ray fluorescence spectrometry (XRF). The results reveal the predominance of goethite α-FeOOH, lepidocrocite γ-FeOOH and akaganeite β-FeOOH which shows the influence of the environmental conditions to which the artworks are exposed in the formation of the oxides that form the superficial patina. Moreover, the findings also point to the identification of akaganeite in a number of works where the conditions of the natural environment are not usually favourable for its formation. From this study it was possible to identify the environmental conditions in which the works suffer greater deterioration and the actual causes of this deterioration, enabling future actions and decisions concerning to the preventive conservation of these works, such as not applying coats of wax or varnish for protection.
A Pinacoteca de São Paulo conta com uma coleção de obras de artistas brasileiros desde o século 17 até os dias de hoje. Uma parte dessa coleção é formada por esculturas em aço patinável expostas em diferentes ambientes. O aço patinável além de oferecer uma boa resistência à corrosão é muito usado em esculturas pela sua aparência atraente e capacidade de autorregeneração. Conhecendo os materiais que constituem uma obra e os fenômenos que atuam sobre ela é possível planejar ações de conservação preventiva a curto, médio e longo prazo. Inicialmente foi realizada análise visual de cada uma das obras e a identificação dos metais com o auxílio de aparelho de fluorescência de raios X portátil (XRF). Posteriormente, amostras foram coletadas para exames de MEV e difração de raios X, onde foram identificados os elementos que constituem as obras e os diferentes óxidos formados em suas superfícies. Para obter informações sobre elementos leves que constituem as obras e que podem estar presentes em sujidades e materiais de corrosão na superfície delas, foi realizada nova identificação in situ com aparelho de fluorescência de raios X por disspersão de energia (EDXRF). Os resultados mostram o predomínio da lepidocrocita, α – goetita e akaganeita mostrando a influência das condições ambientais em que estão expostas as obras na formação dos óxidos que formam a pátina superficial, atentando para a identificação da akaganeita em algumas obras onde as condições naturais do ambiente não são favoráveis para a sua formação. A partir desse estudo foi possível identificar as condições ambientais em que essas obras sofrem mais danos e as causas desses danos possibilitando futuras ações e decisões em relação à conservação preventiva dessas obras, como a não utilização de coberturas utilizando ceras ou vernizes para a proteção.
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Zahari, Eriona. "Fissione Nucleare." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6159/.
Повний текст джерелаАнотація:
Scoprire come funziona la natura non è fine a se stesso. A volte ci vogliono anni, decenni o
ancora di più per comprendere che una scoperta, che può risultare agli occhi dei più
inutile, è in grado di cambiar la vita di molti. Può sembrare di aver buttato via soldi,
tempo e intelletto. Ma la ricerca e lo studio pagano sempre.
La qualità della vita è migliorata e migliorerà notevolmente grazie a chi si è impegnato e si
impegna nella ricerca. Basti pensare alla corrente elettrica e al riscaldamento nelle nostre
case; ai mezzi che ci permettono di spostarci sempre più velocemente in posti sempre più
lontani; a modi di comunicare anch’essi più veloci e più fruibili.
Anche la medicina ha fatto passi da gigante, spesso grazie alle applicazioni della fisica,
soprattutto nel settore della fisica nucleare.
Oggi sentiamo parlare di PET, di risonanza magnetica; tutti nella nostra vita abbiamo fatto
una radiografa, ma pochi conoscono i principi che ci sono dietro queste tecniche mediche.
In questa tesi sarà discusso in modo più accurato l’utilizzo della fissione nucleare e la sua
storia.
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SPERANDIO, LAURA. "New experimental limit on the Pauli exclusion principle violation by electrons from the VIP experiment." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/456.
Повний текст джерелаАнотація:
Il Principio di Esclusione di Pauli (PEP) rappresenta uno dei principi fondamentali della fisica moderna ed è alla base della nostra comprensione della materia. Il PEP è una manifestazione della relazione Spin-Statistica ed è intimamente correlato alla nozione di “identità” delle particelle. Nella sua forma originale il PEP fu una conseguenza della vecchia teoria quantistica di Bohr, secondo la quale un elettrone in un atomo avrebbe potuto muoversi solo attraverso un set discreto di orbite. Sulla base di osservazioni sperimentali (ad esempio i raggi-X negli spettri atomici) Pauli aggiunse il postulato secondo cui in un atomo un solo elettrone può occupare ciascuna delle orbite consentite (includendo la definizione di Spin).
Quando la teoria di Bohr cedette il posto alla meccanica quantistica moderna, in cui le tradizionali orbite tipo-pianeta degli elettroni nell’atomo vennero sostituite dalla più astratta nozione di stati elettronici, il PEP si tradusse nel fatto che due elettroni non avrebbero potuto trovarsi nello stesso stato (cioè i due non avrebbero potuto avere gli stessi numeri quantici). Tale stato di cose è rimasto invariato dopo oltre 60 anni dalla formulazione di Pauli. Di conseguenza, sebbene non ci siano motivi di dubitare la validità del Principio di Esclusione, oggi si dibatte sui suoi limiti.
In questa tesi descriverò il metodo per osservare possibili piccole violazioni del PEP per gli elettroni, attraverso la ricerca di raggi-X provenienti da transizioni anomale in atomi di rame. Tali transizioni sarebbero prodotte da elettroni “nuovi” introdotti attraverso un flusso di corrente in una lamina di rame, che potrebbero essere catturati e compiere transizioni (che violano il PEP) verso un livello 1S già occupato da due elettroni con spin opposto.
Nel 1990, un limite superiore alla probabilità di violazione del PEP fu trovato, sfruttando tale metodo, da Ramberg and Snow (RS). L’esperimento VIP (Violation of the Pauli Exclusion Principle) ha effettuato le misure più precise sulla validità del PEP per elettroni, fissando il limite della probabilità sulla sua violazione a 5.7 x 10-29. Questo risultato, presentato qui per la prima volta, ha migliorato le misure di RS per almeno tre ordini di grandezza e rappresenta il valore di riferimento per tutte quelle teorie che sono correlate ad una possibile violazione della relazione spin-statistica.The Pauli Exclusion Principle (PEP) represents one of the fundamental principles of the modern physics and is at the very basis of our understanding of matter: thus it is of foremost importance to test the limits of its validity. The PEP is a manifestation of the Spin-Statistics relation: the half-integer spin particles (fermions) follow Fermi statistics, while the integer-spin particles (bosons) the Bose –Einstein one, and is intimately related with the notion of “identity” of particles. In its original form the PEP was an adjunct to Bohr’s old quantum theory, which stated that an electron in an atom could only move to one of a discrete set of orbits; on the basis of experimental findings (X-ray atomic spectra for example) Pauli added the postulate that only one electron in the atom can fill each of the allowed orbits (including the spin in the orbit’s definition). When Bohr’s theory gave way to modern quantum mechanics, in which the traditional planet-like orbits of electrons in atoms are replaced by the more abstract notion of the electron states, the PEP survived as the statement that no two electrons could be in the same state (i.e. they cannot have the same quantum numbers). More generally, there is a strong connection between spin and symmetry class, as Pauli stressed in his Nobel Lecture “…we want to stress here a law of Nature which is generally valid, namely, the connection between spin and symmetry class. A half-integer value of the spin quantum number is always connected with antisymmetrical states (exclusion principle), an integer spin with symmetrical states”. In the same Nobel lecture however, Pauli himself says “Already in my original paper I stressed the circumstance that I was unable to give a logical reason for the exclusion principle or to deduce it from more general assumption. I had the feeling and I still have it today, that this is a deficiency. The impression that the shadow of some incompleteness fell here on the bright light of success of the new quantum mechanics seems to me unavoidable”. This statement, more than 60 years after Pauli formulated it, can be repeated practically unchanged – not much progress has been achieved in the deep understanding of the physical origin of the spin-statistics relation. As a consequence, even if today there are no compelling reasons to doubt the validity of the Pauli Exclusion Principle, it still spurs a lively debate on its limits, as testified by the abundant contributions found in the literature and in topical conferences. Here I describe a method to observe possible small violations of the PEP for electrons, through the search for anomalous X-ray transitions in copper atoms, produced by new electrons in a copper block (introduced by a circulating current), which can be captured in a Pauli-forbidden transition to the 1S level, already occupied by two electrons. In 1990, an upper limit on the PEP violation was found using this method by Ramberg and Snow (RS) with a dedicated experiment. The search method is implemented in the VIP (Violation of the Pauli Exclusion Principle) experiment, an international collaboration among 6 Institutions from 4 countries, that has the scientific goal to improve by three-four orders of magnitude the RS’s limit on the probability of PEP violation for electrons, bringing it into the 10^-29–10^-30 region, which may be of particular interest for all those theories related to possible PEP violations, and that would come from new physics. Reaching such limits opens up some very interesting scenarios, as stressed by Duck and Sudarshan: “… recently… membrane theorists have been speculating on a large compactification radius for one of their eleven dimensions, which could give a ratio (for PEP violation) of 10^-30”. VIP has performed the most precise measurement on the validity of PEP for electrons, establishing the limit on the probability of its violation at 5.7 x 10^-29. This result, presented here for the first time, improves on RS measurement by almost three orders of magnitude, and represents the reference value for all those theories that deal with possible violations of spin-statistics relation.
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FRAGIACOMO, ENRICO. "LA DIFFUSIONE ELASTICA PIONE-PROTONE NELLA REGIONE DI INTERFERENZA COULOMBIANO-NUCLEARE." Doctoral thesis, Università degli studi di Trieste, 2000. http://thesis2.sba.units.it/store/handle/item/12689.
Повний текст джерелаКниги з теми "Fisica atomica e nucleare"
1
E, Kingston Arthur, ed. Recent studies in atomic and molecular processes. New York: Plenum Press, 1987.
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ArthurE, Kingston, and Bates David Sir 1916-, eds. Recent advances in atomic and molecular processes. London: Plenum, 1987.
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3
Battimelli, Giovanni, and Vincenzo Patera. L'Istituto nazionale di fisica nucleare: La ricerca italiana in fisica subatomica. Roma: GLF editori Laterza, 2003.
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Chiesa, Giulietto. La menzogna nucleare: Perché tornare all'energia atomica sarebbe gravemente rischioso e completamente inutile. Milano: Ponte alle Grazie, 2010.
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Bruzzaniti, Giuseppe. Dal segno al nucleo: Saggio sulle origini della fisica nucleare. Torino: Bollati Boringhieri, 1993.
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Battimelli, Giovanni. L' Istituto nazionale di fisica nucleare: Storia di una comunità di ricerca. Roma: GLF editori Laterza, 2002.
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Fonda, Luciano. Operazione sincrotrone a Trieste (1980-1987): Storia di una iniziativa scientifica. Trieste: Edizioni "Italo Svevo", 1988.
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Sivuchin, D. Corso di fisica generale. Vol. 1, Fisica atomica. Genova ; Mosca: Edizioni Estere ; Edizioni Mir, 1989.
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Turchetti, Simone. Il caso Pontecorvo: Fisica nucleare, politica e servizi di sicurezza nella guerra fredda. Milano: Sironi, 2007.
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Casalbuoni, Roberto, Daniele Dominici, Massimo Mazzoni, and Giuseppe Pelosi, eds. La Fisica ad Arcetri. Florence: Firenze University Press, 2016. http://dx.doi.org/10.36253/978-88-6655-972-6.
Повний текст джерелаАнотація:
La Mostra La Fisica ad Arcetri. Dalla nascita della Regia Università alle leggi razziali è organizzata dal Dipartimento di Fisica e Astronomia dell’Università di Firenze e dalla Sezione di Firenze dell’Istituto Nazionale di Fisica Nucleare, in collaborazione con l’Archivio Storico del Comune di Firenze, la Biblioteca di Scienze Matematiche Fisiche e Naturali dell’Università di Firenze, la Fondazione Scienza e Tecnica ed il Museo Galileo di Firenze. Essa si tiene da maggio a settembre 2016 presso la Sala Espositiva dell’Archivio Storico comunale in via dell’Oriuolo a Firenze. Il periodo di interesse della Mostra va dalla nascita della Regia Università di Firenze (1924) alla promulgazione delle leggi razziali in Italia da parte del governo di Benito Mussolini (1938). Il materiale esposto proviene dall’Archivio Storico del Comune, dall’Archivio Garbasso, dal Fondo Della Corte, dal Dipartimento di Fisica e Astronomia, dalla Fondazione Scienza e Tecnica e da collezioni private. Il catalogo esce come terzo volume della serie di pubblicazioni associate alla rivista «Il Colle di Galileo».
Частини книг з теми "Fisica atomica e nucleare"
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Balzarotti, Adalberto, Michele Cini, and Massimo Fanfoni. "Fisica atomica." In Atomi, Molecole e Solidi, 1–137. Milano: Springer Milan, 2015. http://dx.doi.org/10.1007/978-88-470-5702-9_1.
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Paderno, Diego, Ileana Bodini, Aldo Zenoni, Antonietta Donzella, Lisa Centofante, and Valerio Villa. "Proof of Concept Experience in the SPES Experiment: First Solutions for Potentiometers Replacement in System Maintenance." In Lecture Notes in Mechanical Engineering, 301–6. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70566-4_48.
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AbstractSPES (Selective Production of Exotic Species) is a large facility, currently under advanced construction at the INFN-LNL (Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro) for the production of Radioactive Ion Beams (RIBs). Coordinated efforts are being dedicated to the development and upgrading of both the accelerator complex and the up-to-date experimental set-ups. This paper describes a work of upgrading as far as the inspection and maintenance of the system is concerned, and it deals with human-centered design methods to reduce the time spent in the radioactive environment of the facility during ordinary maintenance operations and to simplify them, also considering stress conditions of the operator and the mandatory wearable radiation protection devices (such as tracksuit, gloves, oxygen tank mask) which make simple operations difficult.
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Ricci, Renato Angelo. "L’evoluzione della fisica nucleare in Italia dopo Fermi." In Società italiana degli storici della fisica e dell'astronomia : atti del XLI Convegno annuale = proceedings of the 41st Annual Conference. Pisa University Press, 2022. http://dx.doi.org/10.12871/978883339694120.
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