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Pesquisa : G01.249.600 [Categoria DeCS]
Referências encontradas : 170 [refinar]
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[PMID]:28081199
[Au] Autor:Holmlid L
[Ad] Endereço:Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden.
[Ti] Título:Mesons from Laser-Induced Processes in Ultra-Dense Hydrogen H(0).
[So] Source:PLoS One;12(1):e0169895, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Large signals of charged light mesons are observed in the laser-induced particle flux from ultra-dense hydrogen H(0) layers. The mesons are formed in such layers on metal surfaces using < 200 mJ laser pulse-energy. The time variation of the signal to metal foil collectors and the magnetic deflection to a movable pin collector are now studied. Relativistic charged particles with velocity up to 500 MeV u-1 thus 0.75 c are observed. Characteristic decay time constants for meson decay are observed, for charged and neutral kaons and also for charged pions. Magnetic deflections agree with charged pions and kaons. Theoretical predictions of the decay chains from kaons to muons in the particle beam agree with the results. Muons are detected separately by standard scintillation detectors in laser-induced processes in ultra-dense hydrogen H(0) as published previously. The muons formed do not decay appreciably within the flight distances used here. Most of the laser-ejected particle flux with MeV energy is not deflected by the magnetic fields and is thus neutral, either being neutral kaons or the ultra-dense HN(0) precursor clusters. Photons give only a minor part of the detected signals. PACS: 67.63.Gh, 14.40.-n, 79.20.Ds, 52.57.-z.
[Mh] Termos MeSH primário: Hidrogênio
Lasers
Mésons
Modelos Teóricos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
7YNJ3PO35Z (Hydrogen)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170803
[Lr] Data última revisão:
170803
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170113
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0169895


  2 / 170 MEDLINE  
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[PMID]:27725469
[Au] Autor:Nagamine K
[Ad] Endereço:Atomic Physics Laboratory, RIKEN.
[Ti] Título:Radiography with cosmic-ray and compact accelerator muons; Exploring inner-structure of large-scale objects and landforms.
[So] Source:Proc Jpn Acad Ser B Phys Biol Sci;92(8):265-289, 2016.
[Is] ISSN:1349-2896
[Cp] País de publicação:Japan
[La] Idioma:eng
[Ab] Resumo:Cosmic-ray muons (CRM) arriving from the sky on the surface of the earth are now known to be used as radiography purposes to explore the inner-structure of large-scale objects and landforms, ranging in thickness from meter to kilometers scale, such as volcanic mountains, blast furnaces, nuclear reactors etc. At the same time, by using muons produced by compact accelerators (CAM), advanced radiography can be realized for objects with a thickness in the sub-millimeter to meter range, with additional exploration capability such as element identification and bio-chemical analysis. In the present report, principles, methods and specific research examples of CRM transmission radiography are summarized after which, principles, methods and perspective views of the future CAM radiography are described.
[Mh] Termos MeSH primário: Radiação Cósmica
Mésons
[Mh] Termos MeSH secundário: Estudos de Viabilidade
Terapia com Prótons
Pesquisa
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Em] Mês de entrada:1703
[Cu] Atualização por classe:170327
[Lr] Data última revisão:
170327
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161012
[St] Status:MEDLINE


  3 / 170 MEDLINE  
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[PMID]:27340860
[Au] Autor:Zhang W; Ungar K; Liu C; Mailhot M
[Ad] Endereço:Radiation Protection Bureau of Health Canada, 775 Brookfield Road, Ottawa, Ontario, K1A 1C1, Canada. Electronic address: weihua.zhang@hc-sc.gc.ca.
[Ti] Título:Cosmic-muon intensity measurement and overburden estimation in a building at surface level and in an underground facility using two BC408 scintillation detectors coincidence counting system.
[So] Source:J Environ Radioact;162-163:340-346, 2016 Oct.
[Is] ISSN:1879-1700
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:A series of measurements have been recently conducted to determine the cosmic-muon intensities and attenuation factors at various indoor and underground locations for a gamma spectrometer. For this purpose, a digital coincidence spectrometer was developed by using two BC408 plastic scintillation detectors and an XIA LLC Digital Gamma Finder (DGF)/Pixie-4 software and card package. The results indicate that the overburden in the building at surface level absorbs a large part of cosmic ray protons while attenuating the cosmic-muon intensity by 20-50%. The underground facility has the largest overburden of 39 m water equivalent, where the cosmic-muon intensity is reduced by a factor of 6. The study provides a cosmic-muon intensity measurement and overburden assessment, which are important parameters for analysing the background of an HPGe counting system, or for comparing the background of similar systems.
[Mh] Termos MeSH primário: Radiação Cósmica
Mésons
Monitoramento de Radiação/métodos
[Mh] Termos MeSH secundário: Contagem de Cintilação
Espectrometria gama
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170920
[Lr] Data última revisão:
170920
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160625
[St] Status:MEDLINE


  4 / 170 MEDLINE  
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[PMID]:27104698
[Au] Autor:Grinstein B; Martin Camalich J
[Ad] Endereço:Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0319, USA.
[Ti] Título:Weak Decays of Excited B Mesons.
[So] Source:Phys Rev Lett;116(14):141801, 2016 04 08.
[Is] ISSN:1079-7114
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We investigate the decays of the excited (bq[over ¯]) mesons as probes of the short-distance structure of the weak ΔB=1 transitions. These states are unstable under the electromagnetic or strong interactions, although their widths are typically suppressed by phase space. Compared to the pseudoscalar B meson, the purely leptonic decays of the vector B^{*} are not chirally suppressed and are sensitive to different combinations of the underlying weak effective operators. An interesting example is B_{s}^{*}→ℓ^{+}â„“^{-}, which has a rate that can be accurately predicted in the standard model. The branching fraction is B∼10^{-11}, irrespective of the lepton flavor and where the main uncertainty stems from the unmeasured and theoretically not well known B_{s}^{*} width. We discuss the prospects for producing this decay mode at the LHC and explore the possibility of measuring the B_{s}^{*}→ℓℓ amplitude, instead, through scattering experiments at the B_{s}^{*} resonance peak.
[Mh] Termos MeSH primário: Mésons
Modelos Teóricos
[Mh] Termos MeSH secundário: Física Nuclear
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1703
[Cu] Atualização por classe:170327
[Lr] Data última revisão:
170327
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160423
[St] Status:MEDLINE
[do] DOI:10.1103/PhysRevLett.116.141801


  5 / 170 MEDLINE  
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[PMID]:26560837
[Au] Autor:Kusagaya T; Tanaka HK
[Ad] Endereço:Earthquake Research Institute, The University of Tokyo.
[Ti] Título:Muographic imaging with a multi-layered telescope and its application to the study of the subsurface structure of a volcano.
[So] Source:Proc Jpn Acad Ser B Phys Biol Sci;91(9):501-10, 2015.
[Is] ISSN:1349-2896
[Cp] País de publicação:Japan
[La] Idioma:eng
[Ab] Resumo:In conventional muography observations using two detectors for muon tracking, the accidental coincidence of vertical electromagnetic showers generates identical trajectories to the muon tracks. Although muography has favorable properties, which allow direct density measurements inside a volcano, the measured density is lower than the actual value due to these fortuitous trajectories. We performed muography of Usu volcano, and confirmed that, in comparison with a use of two detectors, background noise levels were reduced by more than one order of magnitude using seven detectors for selecting linear trajectories. The resultant muographic image showed a high-density region underneath the central region of Usu volcano. This picture is consistent with the magma intrusion model proposed in previous studies. To clarify the three-dimensional location and actual size of the detected high-density body, multidirectional muographic measurements are necessary.
[Mh] Termos MeSH primário: Fenômenos Ecológicos e Ambientais
Mésons
Telescópios
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1608
[Cu] Atualização por classe:161126
[Lr] Data última revisão:
161126
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:151113
[St] Status:MEDLINE
[do] DOI:10.2183/pjab.91.501


  6 / 170 MEDLINE  
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[PMID]:26024160
[Au] Autor:Geller M; Telem O
[Ad] Endereço:Physics Department, Technion-Institute of Technology, Haifa 32000, Israel.
[Ti] Título:Holographic twin Higgs model.
[So] Source:Phys Rev Lett;114(19):191801, 2015 May 15.
[Is] ISSN:1079-7114
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.
[Mh] Termos MeSH primário: Partículas Elementares
Modelos Teóricos
[Mh] Termos MeSH secundário: Holografia
Mésons
Física Nuclear
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1508
[Cu] Atualização por classe:150530
[Lr] Data última revisão:
150530
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150530
[St] Status:MEDLINE


  7 / 170 MEDLINE  
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[PMID]:25745138
[Au] Autor:Normile D
[Ti] Título:Nuclear disaster. Muons probe Fukushima's ruins.
[So] Source:Science;347(6226):1052-3, 2015 Mar 06.
[Is] ISSN:1095-9203
[Cp] País de publicação:United States
[La] Idioma:eng
[Mh] Termos MeSH primário: Desastres
Acidente Nuclear de Fukushima
Mésons
Contagem de Cintilação/instrumentação
Urânio/análise
[Mh] Termos MeSH secundário: Seres Humanos
Japão
[Pt] Tipo de publicação:NEWS
[Nm] Nome de substância:
4OC371KSTK (Uranium)
[Em] Mês de entrada:1504
[Cu] Atualização por classe:150306
[Lr] Data última revisão:
150306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150307
[St] Status:MEDLINE
[do] DOI:10.1126/science.347.6226.1052


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[PMID]:25688285
[Au] Autor:A L Darwish R; Staudacher AH; Bezak E; Brown MP
[Ad] Endereço:Department of Medical Physics, Royal Adelaide Hospital, Adelaide, Australia ; School of Chemistry and Physics, University of Adelaide, Adelaide, Australia.
[Ti] Título:Autoradiography imaging in targeted alpha therapy with Timepix detector.
[So] Source:Comput Math Methods Med;2015:612580, 2015.
[Is] ISSN:1748-6718
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:There is a lack of data related to activity uptake and particle track distribution in targeted alpha therapy. These data are required to estimate the absorbed dose on a cellular level as alpha particles have a limited range and traverse only a few cells. Tracking of individual alpha particles is possible using the Timepix semiconductor radiation detector. We investigated the feasibility of imaging alpha particle emissions in tumour sections from mice treated with Thorium-227 (using APOMAB), with and without prior chemotherapy and Timepix detector. Additionally, the sensitivity of the Timepix detector to monitor variations in tumour uptake based on the necrotic tissue volume was also studied. Compartmental analysis model was used, based on the obtained imaging data, to assess the Th-227 uptake. Results show that alpha particle, photon, electron, and muon tracks were detected and resolved by Timepix detector. The current study demonstrated that individual alpha particle emissions, resulting from targeted alpha therapy, can be visualised and quantified using Timepix detector. Furthermore, the variations in the uptake based on the tumour necrotic volume have been observed with four times higher uptake for tumours pretreated with chemotherapy than for those without chemotherapy.
[Mh] Termos MeSH primário: Partículas alfa/uso terapêutico
Antineoplásicos/uso terapêutico
Autorradiografia/métodos
Neoplasias/diagnóstico por imagem
[Mh] Termos MeSH secundário: Algoritmos
Animais
Anticorpos Monoclonais/química
Elétrons
Feminino
Mésons
Camundongos
Camundongos Endogâmicos C57BL
Necrose
Transplante de Neoplasias
Neoplasias/tratamento farmacológico
Neoplasias/radioterapia
Fótons
Probabilidade
Radiografia
Radioimunoterapia/métodos
Radioisótopos/química
Tório/uso terapêutico
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antibodies, Monoclonal); 0 (Antineoplastic Agents); 0 (Radioisotopes); 60YU5MIG9W (Thorium)
[Em] Mês de entrada:1510
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150218
[St] Status:MEDLINE
[do] DOI:10.1155/2015/612580


  9 / 170 MEDLINE  
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[PMID]:25375730
[Au] Autor:Salman Z; Prokscha T; Amato A; Morenzoni E; Scheuermann R; Sedlak K; Suter A
[Ad] Endereço:Paul Scherrer Institute, Laboratory for Muon Spin Spectroscopy, CH-5232 Villigen PSI, Switzerland.
[Ti] Título:Direct spectroscopic observation of a shallow hydrogenlike donor state in insulating SrTiO3.
[So] Source:Phys Rev Lett;113(15):156801, 2014 Oct 10.
[Is] ISSN:1079-7114
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We present a direct spectroscopic observation of a shallow hydrogenlike muonium state in SrTiO(3) which confirms the theoretical prediction that interstitial hydrogen may act as a shallow donor in this material. The formation of this muonium state is temperature dependent and appears below ∼ 70K. From the temperature dependence we estimate an activation energy of ∼ 50 meV in the bulk and ∼ 23 meV near the free surface. The field and directional dependence of the muonium precession frequencies further supports the shallow impurity state with a rare example of a fully anisotropic hyperfine tensor. From these measurements we determine the strength of the hyperfine interaction and propose that the muon occupies an interstitial site near the face of the oxygen octahedron in SrTiO(3). The observed shallow donor state provides new insight for tailoring the electronic and optical properties of SrTiO(3)-based oxide interface systems.
[Mh] Termos MeSH primário: Hidrogênio/química
Modelos Teóricos
Óxidos/química
Estrôncio/química
Titânio/química
[Mh] Termos MeSH secundário: Mésons
Análise Espectral/métodos
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Oxides); 7YNJ3PO35Z (Hydrogen); D1JT611TNE (Titanium); OLH4I98373 (strontium titanium oxide); YZS2RPE8LE (Strontium)
[Em] Mês de entrada:1502
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:141107
[St] Status:MEDLINE


  10 / 170 MEDLINE  
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[PMID]:25353500
[Au] Autor:McKenzie I; Salman Z; Giblin SR; Han YY; Leach GW; Morenzoni E; Prokscha T; Suter A
[Ad] Endereço:Centre for Molecular and Materials Science, TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 and Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
[Ti] Título:Polymer dynamics near the surface and in the bulk of poly(tetrafluoroethylene) probed by zero-field muon-spin-relaxation spectroscopy.
[So] Source:Phys Rev E Stat Nonlin Soft Matter Phys;89(2):022605, 2014 Feb.
[Is] ISSN:1550-2376
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The results of many experiments on polymers such as polystyrene indicate that the polymer chains near a free surface exhibit enhanced dynamics when compared with the bulk. We have investigated whether this is the case for poly(tetrafluoroethylene) (PTFE) by using zero-field muon-spin-relaxation spectroscopy to characterize a local probe, the F-Mu(+)-F state, which forms when spin-polarized positive muons are implanted in PTFE. Low-energy muons (implantation energies from 2.0 to 23.0 keV) were used to study the F-Mu(+)-F state between ∼ 23 and 191 nm from the free surface of PTFE. Measurements were also made with surface muons (4.1 MeV) where the mean implantation depth is on the order of ∼ 0.6 mm. The relaxation rate of the F-Mu(+)-F state up to ∼ 150 K was found to be significantly higher for muons implanted at 2.0 keV than for higher implantation energies, which suggests that the polymer chains in a region on the order of a few tens of nanometers from the free surface are more mobile than those in the bulk.
[Mh] Termos MeSH primário: Espectroscopia Dielétrica/métodos
Mésons
Modelos Químicos
Politetrafluoretileno/química
[Mh] Termos MeSH secundário: Simulação por Computador
Teste de Materiais
Polímeros/química
Marcadores de Spin
Propriedades de Superfície
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Polymers); 0 (Spin Labels); 9002-84-0 (Polytetrafluoroethylene)
[Em] Mês de entrada:1511
[Cu] Atualização por classe:141030
[Lr] Data última revisão:
141030
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:141030
[St] Status:MEDLINE



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