TEMPORAL DESCRIPTION OF INTERFERENCE PHENOMENA IN NUCLEAR REACTIONS WITH TWO-PARTICLE CHANNELS

A self-consistent space-time analysis (made in the laboratory system) of the interference between non-resonant (prompt) and resonant (delayed) processes in nuclear reactions with two-particle channels, leads to a generalization of the expressions obtained (in the center-mass system) in the framework of an almost stationary formalism. The role of a new phase parameter φ, which describes the space-time shifts between the sources of the final-particle emission caused by the motion in the laboratory system of the decaying compound-nucleus, is analyzed. We find that in many realistic cases (when φ ~ 1) the effect related to this motion produces noticeable changes in the cross-sections.

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COMBINING CLUSTER STRUCTURE WITH REACTIONS

Modern Physics Letters A ◽

10.1142/s0217732306022067 ◽

2006 ◽

Vol 21 (31n33) ◽

pp. 2419-2428

Author(s):

MARTIN FREER

Keyword(s):

Nuclear Reactions ◽

Cluster Structure ◽

Resonant Scattering ◽

Made In

An examination of the role of the cluster in nuclear reactions is made in the longstanding case of 12 C +12 C cluster resonances in 24 Mg . A description of both resonant scattering and breakup measurements can be found in terms of shape isomeric cluster structures.

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The pre-equilibrium and equilibrium double differential cross sections for the nucleons and light nuclei induce nuclear reactions on 27Al nuclei

Iraqi Journal of Physics (IJP) ◽

10.30723/ijp.v15i32.158 ◽

2019 ◽

Vol 15 (32) ◽

pp. 77-91

Author(s):

Maha Taha Idrees

Keyword(s):

Cross Sections ◽

Differential Cross ◽

Nuclear Reactions ◽

State Density ◽

Light Nuclei ◽

Hole State ◽

Differential Cross Sections ◽

Mass System ◽

Shell Effects ◽

27Al Target

The pre - equilibrium and equilibrium double differential crosssections are calculated at different energies using Kalbach Systematicapproach in terms of Exciton model with Feshbach, Kerman andKoonin (FKK) statistical theory. The angular distribution of nucleonsand light nuclei on 27Al target nuclei, at emission energy in the centerof mass system, are considered, using the Multistep Compound(MSC) and Multistep Direct (MSD) reactions. The two-componentexciton model with different corrections have been implemented incalculating the particle-hole state density towards calculating thetransition rates of the possible reactions and follow up the calculationthe differential cross-sections, that include MSC and MSD models.The finite well depth, isospin, shell effects, Pauli effect, chargeeffect, pairing, surface, angular and linear momentum distributionscorrections are considered in this work. The nucleons (n and p) andlight nuclei (2D and 3T) have been employed as projectiles at thetarget 27Al nuclei and at different incident energies (4MeV, 14 MeVand 14.8MeV). The results have been compared with the availableexperimental and theoretical published work. The comparisons showan acceptable agreement with the TALAYS code (Tendel 2014) forthe reactions: 27Al (n, n) 27Al, 27Al (p, n) 63Zn, 27Al (p, D) 62Cu, 27Al(p, p) 63Cu and 27Al (p, 4He)60Ni and at different emission energiesand angles.

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THE REACTION D(p, γ)He3 BELOW 50 KEV

Canadian Journal of Physics ◽

10.1139/p63-077 ◽

1963 ◽

Vol 41 (5) ◽

pp. 724-736 ◽

Cited By ~ 101

Author(s):

G. M. Griffiths ◽

M. Lal ◽

C. D. Scarfe

Keyword(s):

Angular Distribution ◽

Cross Sections ◽

Center Of Mass ◽

P Wave ◽

Laboratory System ◽

S Wave ◽

Mass System ◽

S Factor ◽

Low Energies ◽

Γ Rays

The yield and angular distribution of the γ rays from the reaction D(p, γ) He3 have been measured with thick heavy-ice targets in the energy range from 24 kev to 48 kev. Assuming a simplified energy dependence the results have been analyzed to give cross sections for p-wave and s-wave capture. At 25 kev in the laboratory system, the cross sections are[Formula: see text]The astrophysical S-factors in the center-of-mass system below 40 kev have been found to be[Formula: see text]for E in center-of-mass kilovolts and[Formula: see text]independent of energy giving a total S-factor for low energies[Formula: see text]with E in center-of-mass kilovolts.

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ACTIVATION CROSS SECTIONS FOR C12(p, pn)C11, O16(p, α)N13, and F19(p, pn)F18

Canadian Journal of Physics ◽

10.1139/p58-132 ◽

1958 ◽

Vol 36 (10) ◽

pp. 1276-1285 ◽

Cited By ~ 56

Author(s):

A. B. Whitehead ◽

J. S. Foster

Keyword(s):

Cross Section ◽

Cross Sections ◽

Smooth Function ◽

Lower Energy ◽

Proton Energy ◽

Proton Irradiation ◽

Nuclear Reactions ◽

Smooth Curve ◽

Laboratory System ◽

Activation Cross Sections

The activation cross sections for proton-induced nuclear reactions were studied in the region from threshold over a range of about 10 Mev proton energy. The scattering and 180°-focussing technique for proton irradiation was employed to realize improved energy resolution.The reaction O16(p, α)N13 exhibited three large peaks at proton energies of 8.6 Mev, 11.3 Mev, and 14.6 Mev in the laboratory system. The maximum cross sections were 46 mb, 55 mb, and 45 mb respectively.Though not so pronounced as in the oxygen case, minor peaks in the cross section for C12(p, pn)C11 + C12(p, d)C11 modulated the previously smooth curve. These occurred at energies of 19.8 Mev, 20.9 Mev, and 22.2 Mev. The known excitation function for this reaction was extended from 32 Mev to 42 Mev and proved to be flat, thereby clarifying the normalization between the higher- and lower-energy regions.The irradiation of F19 with protons to produce F18 yielded a cross section which was a smooth function of energy, and thus differed in shape from the corresponding carbon curve.

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SOME PHENOMENA THEORETICALLY PREDICTED AND EXPLAINED BY THE TIME ANALYSIS OF THE EXPERIMENTAL DATA ON NUCLEAR PROCESSES

International Journal of Modern Physics E ◽

10.1142/s0218301309013713 ◽

2009 ◽

Vol 18 (07) ◽

pp. 1587-1602

Author(s):

V. S. OLKHOVSKY ◽

V. V. DAVYDOVSKY ◽

M. E. DOLINSKA ◽

N. L. DOROSHKO

Keyword(s):

Nuclear Reactions ◽

Center Of Mass ◽

High Energy ◽

The Self ◽

Time Analysis ◽

Stable States ◽

Mass System ◽

Α Decay ◽

Self Consistent ◽

Nuclear Processes

The self-consistent methods in time analysis of nuclear collisions and decays are based on the properties of time as a quantum observable, canonically conjugate to energy, and the appropriate definition of mean durations of quantum collisions, the variances in their distributions, the decay functions, and the surviving functions of the meta-stable states, including radioactive and compound nuclei. Even a simplified application of these methods for the elementary study of the α-decay in the exponential-law-decay approximation resulted in the simple phenomenological method of the determination of the α-particle one-step virtual and real sojourn time inside the parent α-radioactive nucleus between the α-particle successive incoherent multiple internal reflections during the α-decay. And also the direct temporal study of the quasi-monochromatic proton scattering by 12 C and 14 N nuclei at the range of isolated resonances distorted by the nonresonant background, accompanied by the bremsstrahlung, brings to the simple revealing of the possible existence of the delay–advance phenomenon in the proton emission during scattering (in the center-of-mass system). The utilization of the self-consistent methods of time analysis to the study of high-energy nuclear reactions (near and above 0.1 GeV per nucleon in the final compound–fragment formations) resulted in the discovery of the phenomenon of time resonances (or explosions) for such formations. Some perspectives of the further study of the evident temporal phenomena in nuclear processes are also indicated.

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INFLUENCE OF THE ENTRANCE CHANNEL EFFECTS ON THE FORMATION PROCESS OF SUPERHEAVY ELEMENTS

International Journal of Modern Physics E ◽

10.1142/s0218301305003077 ◽

2005 ◽

Vol 14 (03) ◽

pp. 327-332 ◽

Cited By ~ 2

Author(s):

M. KOWAL ◽

Z. ŁOJEWSKI

Keyword(s):

Cross Sections ◽

Formation Process ◽

Heavy Ions ◽

Nuclear Reactions ◽

Quadrupole Deformation ◽

Superheavy Nuclei ◽

Flerov Laboratory ◽

Channel Effects ◽

Spin Distributions

For the description of heavy-ions collisions the importance of multipole deformations of the reaction partners beyond the quadrupole deformation is investigated in particular on fusion cross sections, barrier and spin distributions. The role of fragment orientation in a collision is studied. We have applied our method to Ca – induced reactions leading to superheavy nuclei recently discovered at the Flerov Laboratory of Nuclear Reactions in Dubna. We will show that our predictions are very well confirmed by the recent experiments.

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Visceral leishmaniasis in the state of Sao Paulo, Brazil: spatial and space-time analysis

Revista de Saúde Pública ◽

10.1590/s1518-8787.2016050005965 ◽

2016 ◽

Vol 50 (0) ◽

Cited By ~ 12

Author(s):

Marisa Furtado Mozini Cardim ◽

Marluci Monteiro Guirado ◽

Margareth Regina Dibo ◽

Francisco Chiaravalloti Neto

Keyword(s):

Visceral Leishmaniasis ◽

Sao Paulo ◽

Space Time ◽

The State ◽

Scan Statistics ◽

São Paulo ◽

Time Analysis ◽

Mato Grosso ◽

Incidence And Mortality

ABSTRACT OBJECTIVE To perform both space and space-time evaluations of visceral leishmaniasis in humans in the state of Sao Paulo, Brazil. METHODS The population considered in the study comprised autochthonous cases of visceral leishmaniasis and deaths resulting from it in Sao Paulo, between 1999 and 2013. The analysis considered the western region of the state as its studied area. Thematic maps were created to show visceral leishmaniasis dissemination in humans in the municipality. Spatial analysis tools Kernel and Kernel ratio were used to respectively obtain the distribution of cases and deaths and the distribution of incidence and mortality. Scan statistics were used in order to identify spatial and space-time clusters of cases and deaths. RESULTS The visceral leishmaniasis cases in humans, during the studied period, were observed to occur in the western portion of Sao Paulo, and their territorial extension mainly followed the eastbound course of the Marechal Rondon highway. The incidences were characterized as two sequences of concentric ellipses of decreasing intensities. The first and more intense one was found to have its epicenter in the municipality of Castilho (where the Marechal Rondon highway crosses the border of the state of Mato Grosso do Sul) and the second one in Bauru. Mortality was found to have a similar behavior to incidence. The spatial and space-time clusters of cases were observed to coincide with the two areas of highest incidence. Both the space-time clusters identified, even without coinciding in time, were started three years after the human cases were detected and had the same duration, that is, six years. CONCLUSIONS The expansion of visceral leishmaniasis in Sao Paulo has been taking place in an eastbound direction, focusing on the role of highways, especially Marechal Rondon, in this process. The space-time analysis detected the disease occurred in cycles, in different spaces and time periods. These meetings, if considered, may contribute to the adoption of actions that aim to prevent the disease from spreading throughout the whole territory of São Paulo or to at least reducing its expansion speed.

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Oxygen K near edge structures studied with multiple scattering calculations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104583 ◽

1988 ◽

Vol 46 ◽

pp. 504-505

Author(s):

Xudong Weng ◽

Peter Rez

Keyword(s):

Cross Section ◽

Cross Sections ◽

Partial Cross Section ◽

Energy Window ◽

Edge Structure ◽

Fine Structures ◽

Hydrogenic Model ◽

Electron Energy Loss ◽

Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

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Do Writing Directions Influence How People Map Space onto Time?

Swiss Journal of Psychology ◽

10.1024/1421-0185/a000215 ◽

2018 ◽

Vol 77 (4) ◽

pp. 173-184

Author(s):

Wenxing Yang ◽

Ying Sun

Keyword(s):

Mental Representations ◽

Space Time ◽

Horizontal Axis ◽

Causal Role ◽

Writing Systems ◽

Temporal Cognition ◽

Japanese Speakers ◽

Psychological Experiments ◽

Vertical Up

Abstract. The causal role of a unidirectional orthography in shaping speakers’ mental representations of time seems to be well established by many psychological experiments. However, the question of whether bidirectional writing systems in some languages can also produce such an impact on temporal cognition remains unresolved. To address this issue, the present study focused on Japanese and Taiwanese, both of which have a similar mix of texts written horizontally from left to right (HLR) and vertically from top to bottom (VTB). Two experiments were performed which recruited Japanese and Taiwanese speakers as participants. Experiment 1 used an explicit temporal arrangement design, and Experiment 2 measured implicit space-time associations in participants along the horizontal (left/right) and the vertical (up/down) axis. Converging evidence gathered from the two experiments demonstrate that neither Japanese speakers nor Taiwanese speakers aligned their vertical representations of time with the VTB writing orientation. Along the horizontal axis, only Japanese speakers encoded elapsing time into a left-to-right linear layout, which was commensurate with the HLR writing direction. Therefore, two distinct writing orientations of a language could not bring about two coexisting mental time lines. Possible theoretical implications underlying the findings are discussed.

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