Liu, Jian; Xu, Chang; Ren, Zhongzhou
2017-04-01
Background: Combining the relativistic mean-field (RMF) model and distorted wave Born approximation (DWBA) method, Coulomb form factors for elastic electron scattering have been studied for several stable nuclei (208Pb, 40Ca, 32S, and 24Mg) with a methodology that can be extended to exotic nuclei. Purpose: Previous studies on nuclear Coulomb form factors by the RMF+DWBA method were mainly based on the spherical RMF model. This work aims to further extend the studies to the axially deformed RMF model. Method: The nuclear proton density distributions are first calculated by the deformed RMF model. Next, the axially deformed density distributions are expanded into multipole components. With the spherical ρ0 components, the Coulomb form factors of even-even nuclei are calculated by the DWBA method. Results: For spherical nuclei, the nuclear Coulomb form factors obtained with the deformed RMF model almost coincide with those from the spherical RMF model. For deformed nuclei, Coulomb form factors obtained with the deformed RMF model agree better with the experimental data at the diffraction minima and at high momentum transfers. Conclusions: Results indicate the proton densities calculated from the axially deformed RMF model are valid and reasonable. The electron-scattering experiments will soon be available for exotic nuclei, and the studies in this paper are helpful to interpret the experimental data of deformed exotic nuclei.
Nuclear Structure in Even-Even Nuclei, 24<=Z<=72
Buchhorn, Sarah
2009-10-01
Analysis of the spectra of excited nuclei has been used for decades to reveal trends and build models. Power regressions of the form E(J)=a(√J(J+1) )^b fitted to the yrast line of isotopes reveal an average b of ˜0.5ex4 -0.1em/ -0.15em0.25ex3. It should be noted that this is the value predicted for large angular momenta by the Variable Moment of Inertia model [1,2]. A second plot of RJ (RJ=EJ1^+ /E21^+ ) vs. J reveals curves described by power regressions where 0.66(N=90) transition point in several nuclei. A third chart -- an abbreviated energy level diagram including 01^+ ,02^+ ,21^+ ,22^+ , and 41^+ states illustrates the energy increases at magic numbers, along with the near-degenerate two-phonon triplet of 02^+ , 22^+ , and 41^+ - most clearly observed in isotopes of Z=28,34,36,38,44,46, and 48. Lastly, a fourth chart of E31^- against E21^+ shows positive correlation that is well described by equation E(3&-circ;)=A-B2̂E(21^+ ) - not only for Z=54 [3] but also for Z=36,42-52, and 68. Data obtained through ENSDF database. [1] M.A.J.Mariscotti,G.Sharff-Goldhaber and B.Buck, Phys.Rev.178,1864(1969). [2] M.I. Stockmann and V.G.Zelevinsky, Phys.Lett.41B,19(1972). [3] W.F. Mueller et al.,Phys.Rev.C 73, 014316(2006).
Systematic study of even-even nuclei with Hartree-Fock+BCS method using Skyrme SIII force
Energy Technology Data Exchange (ETDEWEB)
Tajima, Naoki; Takahara, Satoshi; Onishi, Naoki [Tokyo Univ. (Japan). Coll. of Arts and Sciences
1997-03-01
We have applied the Hartree-Fock+BCS method with Skyrme SIII force formulated in a three-dimensional Cartesian-mesh representation to even-even nuclei with 2 {<=} Z {<=} 114. We discuss the results concerning the atomic masses, the quadrupole (m=0, 2) and hexadecapole (m=0, 2, 4) deformations, the skin thicknesses, and the halo radii. We also discuss the energy difference between oblate and prolate solutions and the shape difference between protons and neutrons. (author)
A systematic study of even-even nuclei in the nuclear chart by the relativistic mean field theory
Energy Technology Data Exchange (ETDEWEB)
Sumiyoshi, K.; Hirata, D.; Tanihata, I.; Sugahara, Y.; Toki, H. [Institute of Physical and Chemical Research, Wako, Saitama (Japan)
1997-03-01
We study systematically the properties of nuclei in the whole mass range up to the drip lines by the relativistic mean field (RMF) theory with deformations as a microscopic framework to provide the data of nuclear structure in the nuclear chart. The RMF theory is a phenomenological many-body framework, in which the self-consistent equations for nucleons and mesons are solved with arbitrary deformation, and has a potential ability to provide all the essential information of nuclear structure such as masses, radii and deformations together with single particle states and wave functions from the effective lagrangian containing nuclear interaction. As a first step toward the whole project, we study the ground state properties of even-even nuclei ranging from Z=8 to Z=120 up to the proton and neutron drip lines in the RMF theory. We adopt the parameter set TMA, which has been determined by the experimental masses and charge radii in a wide mass range, for the effective lagrangian of the RMF theory. We take into account the axially symmetric deformation using the constrained method on the quadrupole moment. We provide the properties of all even-even nuclei with all the possible ground state deformations extracted from the deformation energy curves by the constrained calculations. By studying the calculated ground state properties systematically, we aim to explore the general trend of masses, radii and deformations in the whole region of the nuclear chart. We discuss the agreement with experimental data and the predictions such as magicness and triaxial deformations beyond the experimental frontier. (author)
A primer on rotational collective enhancements in even-even nuclei
Energy Technology Data Exchange (ETDEWEB)
Younes, W
2004-07-15
The enhancement of the level density for deformed nuclei relative to the level density in spherical nuclei is calculated. The qualitative behavior of the enhancement factor as a function of excitation energy is explained, and a prescription for a more quantitative description of this behavior is suggested. The results presented here can be found elsewhere in the literature, however the treatments of this topic are dispersed in the literature, are often terse, and require some familiarity with disparate branches of physics. The emphasis of this paper is on step-by-step derivations of the physics and mathematics used in the calculation of level densities and rotational enhancement factors. Pertinent techniques from thermodynamics and group theory are introduced. Appendices provide detailed introductions to the principal mathematical tools.
Low-lying collective quadrupole and octupole strengths in even-even nuclei
Energy Technology Data Exchange (ETDEWEB)
Raman, S.; Nestor, C.W. Jr. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (US)); Kahane, S. (Joint Institute for Heavy-Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, Tennessee 37831 (USA)); Bhatt, K.H. (Department of Physics and Astronomy, University of Mississippi, University, Mississipi 38677 (USA))
1991-02-01
The {ital B}({ital E}2){up arrow} values for the first 2{sup +} state of even-even nuclei in the {ital Z}{ge}50 region are compared with the predictions of several theoretical models. Comparative estimates of the overall agreement with the data are provided. Gaps and discrepancies in the data and examples that show interesting features such as shape changes are discussed. The {ital B}({ital E}2){up arrow} values are examined critically to search for the dynamical Pauli effects predicted by the fermion dynamic symmetry model. The empirical {ital B}({ital E}2){up arrow} and {ital B}({ital E}3){up arrow} systematics are employed to obtain a measure of the harmonicity of the quadrupole and octupole vibrations. The fraction of the energy-weighted sum-rule strength exhausted by the sum of all known low-lying 2{sup +} states below 2.3 MeV is found to be surprisingly constant in the 60{lt}{ital A}{lt}250 region except near closed shells.
Triaxial quadrupole dynamics and the inner fission barrier of some heavy even-even nuclei
Benrabia, K.; Medjadi, D. E.; Imadalou, M.; Quentin, P.
2017-09-01
Background: Inner fission barriers of actinide nuclei have been known for a long time to be unstable with respect to the axial symmetry. On the other hand, taking into account the effect of the relevant adiabatic mass parameter reduces or even may wash out this instability. A proper treatment of the dynamics for both axial and triaxial modes is thus crucial to accurately determine the corresponding fission barriers. This entails in particular an accurate description of pairing correlations. Purpose: We evaluate the potential energies, moments of inertia, and vibrational mass parameters in a two-dimensional relevant deformation space (corresponding to the usual β and γ quadrupole deformation parameters) for four actinide nuclei (236U, 240Pu, 248Cm, and 252Cf). We assess the relevance of our approach to describe the dynamics for a triaxial mode by computing the low energy spectra (exploring thus mainly the equilibrium deformation region). We evaluate the inner fission barrier heights releasing the axial symmetry constraint. Method: Calculations within the Hartree-Fock plus BCS approach are performed using the SkM* Skyrme effective interaction in the particle-hole channel and a seniority force in the particle-particle channel. The intensity of this residual interaction has been fixed to allow a good reproduction of some odd-even mass differences in the actinide region. Adiabatic mass parameters for the rotational and vibrational modes are calculated using the Inglis-Belyaev formula supplemented by a global renormalization factor taking into account the so-called Thouless-Valatin corrections. Spectra are obtained through the diagonalization of the corresponding Bohr collective Hamiltonian. Results: The experimental low energy spectra are qualitatively well reproduced by our calculations for the considered nuclei. Inner fission barrier heights are calculated and compared with available estimates from various experimental data. The reproduction of the data is better
Symmetries of Quadrupole-Collective Vibrational Motion in Transitional Even-Even 124−134Xenon Nuclei
Pietralla, N; Rainovski, G; Ahn, T; Bauer, C; Leske, J; Möller, O; Möller, T
2010-01-01
Projectile-Coulomb excitation of Xe isotopes has been performed at ANL using the Gammasphere array for the detection of γ-rays. The one-quadrupole phonon 2+ 1,ms mixed-symmetry state (MSS) has been traced in the stable N=80 isotones down to 134Xe. First, the data on absolute E2 andM1 transition rates quantify the amount of F-spin symmetry in these nuclei and provide a new local measure for the pn-QQ interaction. Second, the evolution of the 2+ 1,ms state has been studied along the sequence of stable even-even 124−134Xe isotopes that are considered to form a shape transition path from vibrational nuclei with vibrational U(5) symmetry near N=82 to γ-softly deformed shapes with almost O(6) symmetry. Third, our data on more than 50 absolute E2 transition rates between off-yrast low-spin states of 124,126Xe enable us to quantitatively test O(6) symmetry in these nuclei. As a result we find that O(6) symmetry is more strongly broken in the A=130 mass region than previously thought. The data will be discussed.
Descriptive study of the even-even actinide nuclei 230 - 234Th isotopes using IBM-1
Al-Dahan, N.
2017-06-01
The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model (IBM-1). Predictions are given for the excited state energies for the ground state, β and γ-bands, the transition probabilities between these states, the rotational moment of inertia, and the energy staggering in the γ-band energies. The results of these calculations are compared with the experimental data on these isotopes.
Analytic formula for B(E2) values in even-even nuclei with A>60
Wolf, A.; Scholten, O.; Casten, R. F.
1991-01-01
An approximate analytic formula for calculating B(E22+1-->0+1) transition probabilities is proposed. We show that this formula reproduces quite accurately numerical calculations based on the interacting-boson model (IBM), and experimental data for a large number of nuclei from Zn to Pt, and in the
Unique first-forbidden β-decay transitions in odd-odd and even-even heavy nuclei
Nabi, Jameel-Un; Çakmak, Necla; Majid, Muhammad; Selam, Cevad
2017-01-01
The allowed Gamow-Teller (GT) transitions are the most common weak nuclear processes of spin-isospin (στ) type. These transitions play a key role in numerous processes in the domain of nuclear physics. Equally important is their contribution in astrophysics, particularly in nuclear synthesis and supernova-explosions. In situations where allowed GT transitions are not favored, first-forbidden transitions become significant, specifically in medium heavy and heavy nuclei. For neutron-rich nuclei, first-forbidden transitions are favored mainly due to the phase-space amplification for these transitions. In this work we calculate the allowed GT as well as unique first-forbidden (U1F) | ΔJ | = 2 transitions strength in odd-odd and even-even nuclei in mass range 70 ≤ A ≤ 214. Two different pn-QRPA models were used with a schematic separable interaction to calculate GT and U1F transitions. The inclusion of U1F strength improved the overall comparison of calculated terrestrial β-decay half-lives in both models. The ft values and reduced transition probabilities for the 2- ⟷0+ transitions were also calculated. We compared our calculations with the previously reported correlated RPA calculation and experimental results. Our calculations are in better agreement with measured data. For stellar applications we further calculated the allowed GT and U1F weak rates. These include β±-decay rates and electron/positron capture rates of heavy nuclei in stellar matter. Our study shows that positron and electron capture rates command the total weak rates of these heavy nuclei at high stellar temperatures.
Evolution of collectivity in a ground-{gamma}-band mixing scheme for even-even transitional nuclei
Energy Technology Data Exchange (ETDEWEB)
Lalkovski, S [Faculty of Physics, University of Sofia, 5 James Bourchier, blvd. 1164 Sofia (Bulgaria); Minkov, N [Institute of Nuclear Research and Nuclear Energy, 72 Tzarigrad Road, 1784 Sofia (Bulgaria)
2005-05-01
We propose an extended band-mixing formalism capable of describing the structure of the ground- and {gamma}-bands in a wide range of collective spectra beyond the regions of well-deformed nuclei. We apply it to explain the odd-even staggering effect observed in the {gamma}-bands of Mo, Ru and Pd nuclei and to obtain on this basis a consistent interpretation of new experimental data in the neutron rich region. As a result the systematic behaviour of the staggering effect, together with the mutual ground-{gamma}-band disposition, interband mixing and intraband level spacing are explained as the manifestation of respective changes in nuclear collectivity.
ANALYTIC FORMULA FOR B(E2) VALUES IN EVEN-EVEN NUCLEI WITH A-GREATER-THAN-60
SCHOLTEN, O; CASTEN, RF
An approximate analytic formula for calculating B(E2;2(1)+ --> 0(1)+) transition probabilities is proposed. We show that this formula reproduces quite accurately numerical calculations based on the interacting-boson model (IBM), and experimental data for a large number of nuclei from Zn to Pt, and
Decay out of the yrast and excited highly-deformed bands in the even-even nucleus {sup 134}Nd
Energy Technology Data Exchange (ETDEWEB)
Petrache, C.M.; Bazzacco, D.; Lunardi, S. [Sezione di Padova (Italy)] [and others
1996-12-31
The resolving power achieved by the new generation of {gamma}-ray detector arrays allows now to observe transitions with intensities of the order of {approximately}10{sup {minus}3} of the population of the final residual nucleus, making therefore feasible the study of the very weakly populated excited bands built on the superdeformed (SD) minimum or of the decay out of the SD bands. As a matter of fact, numerous excited SD bands have been observed in the different regions of superdeformation, which led to a deeper understanding of the single-particle excitation in the second minimum. The first experimental breakthrough in the study of the decay out process has been achieved in the odd-even {sup 133,135}Nd nuclei of the A=130 mass region. There, the observation of the discrete linking transitions has been favored by the relatively higher intensity of the highly-deformed (HD) bands ({approximately}10%), as well as by the small excitation energy with respect to the yrast line in the decay-out region ({approximately}1 MeV). No discrete linking transitions have been so far observed in the A=80, 150 mass regions. The present results suggest that the decay out of the HD bands in {sup 134}Nd is triggered by the crossing with the N=4 [402]5/2{sup +} Nilsson orbital, that has a smaller deformation than the corresponding N=6 intruder configuration. The crossing favours the mixing with the ND rotational bands strongly enhancing the decay-out process and weakening the in-band transition strength. The HD band becomes fragmented and looses part of its character. The intensity of the decay-out transitions increases when the spin of the HD state decreases, indicating enhanced ND amplitude in the wavefunction when going down the band. Lifetime measurements of the HD bands are crucial to further elucidate the decay-out process.
Bouhelal, M.; Labidi, M.; Haas, F.; Caurier, E.
2017-10-01
The electric-octupole E 3 transition strengths from the first 3- state to the ground-state transition in s d shell even-even nuclei with A =16 to 40 are investigated within the shell model framework using the effective (0+1)ℏ ω PSDPF interaction. For this type of transition, new effective charges for protons and neutrons have been determined. Their values 1.36 e for protons and 0.48 e for neutrons are close to those obtained previously for electric-quadrupole E 2 transitions in s d shell nuclei. The calculated E 3 transition strengths from the 31 -→0gs + transitions are compared to a compilation of experimental E 3 data for even-even nuclei throughout the s d shell.
Robin, C.; Pillet, N.; Dupuis, M.; Le Bloas, J.; Peña Arteaga, D.; Berger, J.-F.
2017-04-01
Background: The variational multiparticle-multihole configuration mixing approach to nuclei has been proposed about a decade ago. While the first applications followed rapidly, the implementation of the full formalism of this method has only been recently completed and applied in C. Robin, N. Pillet, D. Peña Arteaga, and J.-F. Berger, [Phys. Rev. C 93, 024302 (2016)], 10.1103/PhysRevC.93.024302 to 12C as a test-case. Purpose: The main objective of the present paper is to carry on the study that was initiated in that reference, in order to put the variational multiparticle-multihole configuration mixing method to more stringent tests. To that aim we perform a systematic study of even-even s d -shell nuclei. Method: The wave function of these nuclei is taken as a configuration mixing built on orbitals of the s d -shell, and both the mixing coefficients of the nuclear state and the single-particle wave functions are determined consistently from the same variational principle. As in the previous works, the calculations are done using the D1S Gogny force. Results: Various ground-state properties are analyzed. In particular, the correlation content and composition of the wave function as well as the single-particle orbitals and energies are examined. Binding energies and charge radii are also calculated and compared to experiment. The description of the first excited state is also examined and the corresponding transition densities are used as input for the calculation of reaction processes such as inelastic electron and proton scattering. Special attention is paid to the effect of the optimization of the single-particle states consistently with the correlations of the system. Conclusions: The variational multiparticle-multihole configuration mixing approach is systematically applied to the description of even-even s d -shell nuclei. Globally, the results are satisfying and encouraging. In particular, charge radii and excitation energies are nicely reproduced. However
Energy Technology Data Exchange (ETDEWEB)
Kaplan, A., E-mail: abdullahkaplan@sdu.edu.tr [Süleyman Demirel Univesity, Faculty of Arts and Sciences, Department of Physics (Turkey); Sarpün, İ. H. [Afyon Kocatepe University, Faculty of Arts and Sciences, Department of Physics (Turkey); Aydın, A. [Kırıkkale University, Faculty of Arts and Sciences, Department of Physics (Turkey); Tel, E. [Osmaniye Korkut Ata University, Faculty of Arts and Sciences, Department of Physics (Turkey); Çapalı, V.; Özdoǧan, H. [Süleyman Demirel Univesity, Faculty of Arts and Sciences, Department of Physics (Turkey)
2015-01-15
There are several level density models that can be used to predict photo-neutron cross sections. Some of them are Constant Temperature + Fermi Gas Model (CTFGM), Back-Shifted Fermi Gas Model (BSFM), Generalized Superfluid Model (GSM), Hartree-Fock-Bogoliubov microscopic Model (HFBM). In this study, the theoretical photo-neutron cross sections produced by (γ, 2n) reactions for several eveneven lanthanide nuclei such as {sup 140,142}Ce, {sup 142,144,146,148,150}Nd, {sup 144,148,150,152,154}Sm, and {sup 160}Gd have been calculated on the different level density models as mentioned above by using TALYS 1.6 and EMPIRE 3.1 computer codes for incident photon energies up to 30 MeV. The obtained results have been compared with each other and available experimental data existing in the EXFOR database. Generally, at least one level density model cross-section calculations are in agreement with the experimental results for all reactions except {sup 144}Sm(γ, 2n){sup 142}Sm along the incident photon energy, TALYS 1.6 BSFM option for the level density model cross-section calculations can be chosen if the experimental data are not available or are improbable to be produced due to the experimental difficulty.
Energy Technology Data Exchange (ETDEWEB)
Rudolph, D.; Baktash, C.; Gross, C.J.; Jin, H.; Yu, C.H. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Rudolph, D. [Sektion Physik der Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Gross, C.J. [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831 (United States); Satula, W. [Department of Physics, University of Tennessee, Knoxville, Tennessee 37996 (United States); Satula, W. [Joint Institute for Heavy Ion Research, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Satula, W. [Institute of Theoretical Physics, Warsaw University, PL-00681 Warsaw (Poland); Wyss, R. [The Royal Institute of Technology, Physics Department Frescati, S-104 05 Stockholm (Sweden); Birriel, I.; Saladin, J.X.; Winchell, D.F.; Wood, V.Q. [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Devlin, M.; LaFosse, D.R.; Lerma, F.; Sarantites, D.G. [Chemistry Department, Washington University, St. Louis, Missouri 63130 (United States); Sylvan, G.N.; Tabor, S.L. [Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States)
1997-07-01
High-spin states of T{sub z}=1 nuclei were studied with the reactions {sup 58}Ni({sup 28}Si,3{alpha}){sup 74}Kr, {sup 58}Ni({sup 28}Si,2{alpha}){sup 78}Sr, and {sup 58}Ni({sup 28}Si,2p2n){sup 82}Zr at 130 MeV beam energy. The Gammasphere array in conjunction with the 4{pi} charged-particle detector array Microball was used to detect {gamma} rays in coincidence with evaporated light charged particles. The known {pi}=+, {alpha}=0 yrast bands were extended to I=28{h_bar} at 20 MeV excitation energy. For all three nuclei, a number of positive- and negative-parity sidebands were established; altogether 15 new rotational bands were found. The data are discussed using the pairing-and-deformation self-consistent total Routhian surface (TRS) model: High-spin structures of {sup 74}Kr and {sup 78}Sr are governed by the shell gaps at large prolate deformation while {sup 82}Zr seems to exhibit shape coexistence. Nearly identical bands were established which may be explained as arising from the fp orbits acting as spectators at very elongated shapes. The experimental data in these T{sub z}=1 nuclei are in good agreement with predictions of the TRS model using conventional T=1 like-nucleon pairing correlations. {copyright} {ital 1997} {ital The American Physical Society}
Effective field theory for triaxially deformed nuclei
Chen, Q. B.; Kaiser, N.; Meißner, Ulf-G.; Meng, J.
2017-10-01
Effective field theory is generalized to investigate the rotational motion of triaxially deformed even-even nuclei. The Hamiltonian for the triaxial rotor is obtained up to next-to-leading order within the effective field theory formalism. Its applicability is examined by comparing with a five-dimensional rotor-vibrator Hamiltonian for the description of the energy spectra of the ground state and γ band in Ru isotopes. It is found that by taking into account the next-to-leading order corrections, the ground state band in the whole spin region and the γ band in the low spin region are well described. The deviations for high-spin states in the γ bands point towards the importance of including vibrational degrees of freedom in the effective field theory formulation.
Effective field theory for triaxially deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Chen, Q.B. [Technische Universitaet Muechen, Physik-Department, Garching (Germany); Peking University, State Key Laboratory of Nuclear Physics and Technology, School of Physics, Beijing (China); Kaiser, N. [Technische Universitaet Muechen, Physik-Department, Garching (Germany); Meissner, Ulf G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Institute for Advanced Simulation, Institut fuer Kernphysik, Juelich Center for Hadron Physics and JARA-HPC, Forschungszentrum Juelich, Juelich (Germany); Meng, J. [Peking University, State Key Laboratory of Nuclear Physics and Technology, School of Physics, Beijing (China); Beihang University, School of Physics and Nuclear Energy Engineering, Beijing (China); University of Stellenbosch, Department of Physics, Stellenbosch (South Africa)
2017-10-15
Effective field theory is generalized to investigate the rotational motion of triaxially deformed even-even nuclei. The Hamiltonian for the triaxial rotor is obtained up to next-to-leading order within the effective field theory formalism. Its applicability is examined by comparing with a five-dimensional rotor-vibrator Hamiltonian for the description of the energy spectra of the ground state and γ band in Ru isotopes. It is found that by taking into account the next-to-leading order corrections, the ground state band in the whole spin region and the γ band in the low spin region are well described. The deviations for high-spin states in the γ bands point towards the importance of including vibrational degrees of freedom in the effective field theory formulation. (orig.)
Spin dependence of even-even nucleus shape in the model of Davydov-Chaban
Kashuba, I E
2002-01-01
The shape parameters of the even-even nuclei sup 1 sup 5 sup 4 Gd, sup 1 sup 5 sup 6 sup , sup 1 sup 5 sup 8 sup , sup 1 sup 6 sup 0 Dy, sup 1 sup 6 sup 4 sup , sup 1 sup 6 sup 8 Er, sup 1 sup 6 sup 8 Yb, sup 1 sup 7 sup 6 Hf, sup 1 sup 8 sup 0 W are calculated within the phenomenological model of the nonaxial soft by beta-oscillation deformed nucleus. The spin dependence of the softness, nonaxiality and energy factor is assumed
Predicting the optical observables for nucleon scattering on even-even actinides
Martyanov, D. S.; Soukhovitskiĩ, E. Sh.; Capote, R.; Quesada, J. M.; Chiba, S.
2017-09-01
The previously derived Lane consistent dispersive coupled-channel optical model for nucleon scattering on 232Th and 238U nuclei is extended to describe scattering on even-even actinides with Z = 90-98. A soft-rotator-model (SRM) description of the low-lying nuclear structure is used, where the SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate the coupling matrix elements of the generalized optical model. The “effective” deformations that define inter-band couplings are derived from the SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a dynamic monopolar term to the deformed potential, leading to additional couplings between rotational bands. The fitted static deformation parameters are in very good agreement with those derived by Wang and collaborators using the Weizsäcker-Skyrme global mass model (WS4), allowing use of the latter to predict cross sections for nuclei without experimental data. A good description of the scarce “optical” experimental database is achieved. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus formation cross sections, which is significantly different from that calculated with rigid-rotor potentials coupling the ground-state rotational band. The derived parameters can be used to describe both neutron- and proton-induced reactions. Supported by International Atomic Energy Agency, through the IAEA Research Contract 19263, by the Spanish Ministry of Economy and Competitivity under Contracts FPA2014-53290-C2-2-P and FPA2016-77689-C2-1-R.
Magnetic excitations in deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Nojarov, R. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik
1995-08-01
Cross sections for inelastic electron scattering and energy distributions of M1 and E2 strengths of K{sup {pi}} - 1{sup +} excitations in titanium, rare-earth, and actinide nuclei are studied microscopically within QRPA. The spin M1 strength has two peaks, isoscalar and isovector, residing between the low-and high-energy orbital M1 strength. The latter is strongly fragmented and lies in the region of the IVGQR, where the (e,e`) cross sections are almost one order of magnitude larger for E2 than for M1 excitations. Comparison with the quantized isovector rotor allows the interpretation of all the orbital M1 excitations at both low and high energies as manifestation of the collective scissors mode. (author).
Test of Pseudospin Symmetry in Deformed Nuclei
Ginocchio, J. N.; Leviatan, A.; Meng, J.; Zhou, Shan-Gui
2003-01-01
Pseudospin symmetry is a relativistic symmetry of the Dirac Hamiltonian with scalar and vector mean fields equal and opposite in sign. This symmetry imposes constraints on the Dirac eigenfunctions. We examine extensively the Dirac eigenfunctions of realistic relativistic mean field calculations of deformed nuclei to determine if these eigenfunctions satisfy these pseudospin symmetry constraints.
Phase Transitions in Even-Even Palladium Isotopes
Directory of Open Access Journals (Sweden)
Diab S. M.
2009-01-01
Full Text Available The positive and negative parity states of the even-even palladium isotopes were stud- ied within the frame work of the interacting boson approximation model (IBA-1. The energy spectra, potential energy surfaces, electromagnetic transition probabilities, back bending and staggering effect have been calculated. The potential energy surfaces show smooth transition from vibrational-like to gamma-soft and finally to rotational-like nu- clei. Staggering effectle, has been observed between the positive and negative parity states in palladium isotopes. The agreement between theoretical predictions and exper- imental values are fairly good.
Directory of Open Access Journals (Sweden)
Minkov N.
2016-01-01
Full Text Available We study the effects of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even heavy and superheavy nuclei. The neutron two-quasiparticle (2qp isomeric energies and magnetic dipole moments are calculated within a deformed shell model with the Bardeen-Cooper- Schrieffer (BCS pairing interaction over a wide range of quadrupole and octupole deformations. We found that in most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation, while the 2qp energies indicate regions of nuclei in which the presence of high-K isomeric states may be associated with the presence of octupole softness or even with octupole deformation. In the present work we also examine the influence of the BCS pairing strength on the energy of the blocked isomer configuration. We show that the formation of 2qp energy minima in the space of quadrupole-octupole and eventually higher multipolarity deformations is a subtle effect depending on nuclear pairing correlations.
Monopole Strength Function of Deformed Superfluid Nuclei
Energy Technology Data Exchange (ETDEWEB)
Stoitsov, M. V. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Kortelainen, E. M. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Nakatsukasa, T. [RIKEN, Japan; Losa, C. [International School for Advanced Studies (SISSA), Trieste, Italy; Nazarewicz, Witold [ORNL
2011-01-01
We present an efficient method for calculating strength functions using the finite amplitude method (FAM) for deformed superfluid heavy nuclei within the framework of the nuclear density functional theory. We demonstrate that FAM reproduces strength functions obtained with the fully self-consistent quasi-particle random-phase approximation (QRPA) at a fraction of computational cost. As a demonstration, we compute the isoscalar and isovector monopole strength for strongly deformed configurations in ^{240}Pu by considering huge quasi-particle QRPA spaces. Our approach to FAM, based on Broyden's iterative procedure, opens the possibility for large-scale calculations of strength distributions in well-bound and weakly bound nuclei across the nuclear landscape.
Proton emission from highly deformed nuclei
Delion, D S
2002-01-01
We give the description of proton emission involving transition between excited states of the even-even cores. The contribution of the rotational energy is properly taken into account. It is shown that the proton decay width is practically independent of the matching radius for a large interval of values. By using the universal parametrisation of the Woods-Saxon potential the agreement with the experimental data for the transitions between ground states is satisfactory. We show that the half-life to first excited state in sup 1 sup 3 sup 1 Eu is much more sensitive to the mean field parameters then the transition between ground states. The influence of the difference between the parent and daughter deformations is studied. (authors)
Coulomb form factors of odd-A nuclei within an axially deformed relativistic mean-field model
Liu, Jian; Xu, Chang; Wang, Shuo; Ren, Zhongzhou
2017-09-01
Background: The nuclear Coulomb form factor | FC(q) | 2 is a useful tool to study nuclear structure. For spherical nuclei, | FC(q) | 2 can be calculated by combining the spherical relativistic mean-field (RMF) model and the distorted wave Born approximation (DWBA) method. Purpose: In a previous paper, the axially deformed RMF model + DWBA method was successfully applied to study the Coulomb form factors of deformed even-even nuclei. In this paper, we further extend this method to study the Coulomb form factors of deformed odd-A nuclei. Method: First, the charge distributions of odd-A nuclei are calculated with the deformed RMF model and expanded into multipole components. Next, with the multipole moment charge distributions, the Coulomb multipoles C 0 , C 2 , and C 4 are calculated. Finally, by summing over Coulomb multipoles required, the Coulomb form factors of odd-A nuclei can be obtained. Results: For deformed odd-A nuclei, the theoretical Coulomb form factors calculated from the deformed RMF charge densities are in better agreement with the experimental data. For nuclei with J ≥1 , the diffraction minima of Coulomb form factors are much flatter, which is due to the contributions of quadrupole charge distributions. Conclusions: Results indicate that the axially deformed RMF model can give reasonable descriptions for multipole moment charge distributions of odd-A nuclei. The method in this paper can provide a useful guide for future experiments of electron scattering off exotic odd-A nuclei.
Nature of the Excited States of the Even-Even 98-108 Ru Isotopes
Directory of Open Access Journals (Sweden)
Eid S. A.
2008-10-01
Full Text Available The positive and negative parity states of the even-even 98-108 Ru isotopes are studied within the frame work of the interacting boson approximation model (IBA-1. The calculated levels energy, potential energy surfaces, $V(eta,gamma$, and the electromagnetic transition probabilities, B(E1 and B(E2, show that ruthenium isotopes are transitional nuclei. Staggering effectle, $Delta I = 1$, has been observed between the positive and negative parity states in some of ruthenium isotopes. The electric monopole strength, X(E0/E2, has been calculated. All calculated values are compared with the available experimental and theoretical data wher reasonable agreement has obtained.
Reduced widths of alpha -decay of near-magic even-even nuclei
Kar Yan, N
1972-01-01
Precision on-line investigations on the linear heavy-ion Berkeley accelerator, and on the CERN synchrophasotron were carried out recently on new alpha -emitters. The results obtained are analysed with a view to finding the degree of correspondence, or disagreement, with the authors' own ideas about alpha -decay processes. The discussion is confined to examining even isotopes of polonium, radon, radium and thorium Several theoretical and experimental plots are given of reduced widths of alpha -disintegration for different regions of shell filling and a comparison is made between barrier penetration coefficients, obtained by rigorous methods and with the aid of WKB- approximation, for /sup 212/Po, /sup 208/Po and /sup 212/Po isotopes. (24 refs).
Analysis of Orientation Relations Between Deformed Grains and Recrystallization Nuclei
DEFF Research Database (Denmark)
West, Stine S.; Winther, Grethe; Juul Jensen, Dorte
2011-01-01
Nucleation in 30 pct rolled high-purity aluminum samples was investigated by the electron backscattering pattern method before and after annealing. A total of 29 nuclei including two twins were observed, and approximately one third of these nuclei had orientations not detected in the deformed sta...
Lifetime measurement of neutron-rich even-even molybdenum isotopes
Ralet, D.; Pietri, S.; Rodríguez, T.; Alaqeel, M.; Alexander, T.; Alkhomashi, N.; Ameil, F.; Arici, T.; Ataç, A.; Avigo, R.; Bäck, T.; Bazzacco, D.; Birkenbach, B.; Boutachkov, P.; Bruyneel, B.; Bruce, A. M.; Camera, F.; Cederwall, B.; Ceruti, S.; Clément, E.; Cortés, M. L.; Curien, D.; De Angelis, G.; Désesquelles, P.; Dewald, M.; Didierjean, F.; Domingo-Pardo, C.; Doncel, M.; Duchêne, G.; Eberth, J.; Gadea, A.; Gerl, J.; Ghazi Moradi, F.; Geissel, H.; Goigoux, T.; Goel, N.; Golubev, P.; González, V.; Górska, M.; Gottardo, A.; Gregor, E.; Guastalla, G.; Givechev, A.; Habermann, T.; Hackstein, M.; Harkness-Brennan, L.; Henning, G.; Hess, H.; Hüyük, T.; Jolie, J.; Judson, D. S.; Jungclaus, A.; Knoebel, R.; Kojouharov, I.; Korichi, A.; Korten, W.; Kurz, N.; Labiche, M.; Lalović, N.; Louchart-Henning, C.; Mengoni, D.; Merchán, E.; Million, B.; Morales, A. I.; Napoli, D.; Naqvi, F.; Nyberg, J.; Pietralla, N.; Podolyák, Zs.; Pullia, A.; Prochazka, A.; Quintana, B.; Rainovski, G.; Reese, M.; Recchia, F.; Reiter, P.; Rudolph, D.; Salsac, M. D.; Sanchis, E.; Sarmiento, L. G.; Schaffner, H.; Scheidenberger, C.; Sengele, L.; Singh, B. S. Nara; Singh, P. P.; Stahl, C.; Stezowski, O.; Thoele, P.; Valiente Dobon, J. J.; Weick, H.; Wendt, A.; Wieland, O.; Winfield, J. S.; Wollersheim, H. J.; Zielinska, M.; PreSPEC Collaboration
2017-03-01
Background: In the neutron-rich A ≈100 mass region, rapid shape changes as a function of nucleon number as well as coexistence of prolate, oblate, and triaxial shapes are predicted by various theoretical models. Lifetime measurements of excited levels in the molybdenum isotopes allow the determination of transitional quadrupole moments, which in turn provides structural information regarding the predicted shape change. Purpose: The present paper reports on the experimental setup, the method that allowed one to measure the lifetimes of excited states in even-even molybdenum isotopes from mass A =100 up to mass A =108 , and the results that were obtained. Method: The isotopes of interest were populated by secondary knock-out reaction of neutron-rich nuclei separated and identified by the GSI fragment separator at relativistic beam energies and detected by the sensitive PreSPEC-AGATA experimental setup. The latter included the Lund-York-Cologne calorimeter for identification, tracking, and velocity measurement of ejectiles, and AGATA, an array of position sensitive segmented HPGe detectors, used to determine the interaction positions of the γ ray enabling a precise Doppler correction. The lifetimes were determined with a relativistic version of the Doppler-shift-attenuation method using the systematic shift of the energy after Doppler correction of a γ -ray transition with a known energy. This relativistic Doppler-shift-attenuation method allowed the determination of mean lifetimes from 2 to 250 ps. Results: Even-even molybdenum isotopes from mass A =100 to A =108 were studied. The decays of the low-lying states in the ground-state band were observed. In particular, two mean lifetimes were measured for the first time: τ =29 .7-9.1+11.3 ps for the 4+ state of 108Mo and τ =3 .2-0.7+0.7 ps for the 6+ state of 102Mo. Conclusions: The reduced transition strengths B (E 2 ) , calculated from lifetimes measured in this experiment, compared to beyond
Octupole Deformed Nuclei in the Actinide Region
Thorsteinsen, T; Rubio barroso, B; Simpson, J; Gulda, K; Sanchez-vega, M; Cocks, J; Nybo, K; Garcia borge, M; Aas, A; Fogelberg, B; Honsi, J; Smith, G; Naumann, R; Grant, I
2002-01-01
The aim of the present study is to investigate the limits of the "island" of octupole deformation in the mass region A=225. It is of particular importance to demonstrate experimentally the sudden disappearance of the stable octupole deformation in the presence of a well developed quadrupole field. \\\\ \\\\In order to establish the upper border line the $\\beta$ -decay chains of $^{227}$Rn $\\rightarrow ^{227}$Fr $\\rightarrow ^{227}$Ra and $^{231}$Fr $\\rightarrow ^{231}$Ra $\\rightarrow ^{231}$Ac were studied at PSB-ISOLDE using advanced fast timing and $\\gamma$-ray spectroscopy techniques. The lifetimes of the excited states have been measured in the picosecond range using the time-delayed $\\beta\\gamma\\gamma$(t) method.
Modeling level structures of odd-odd deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Hoff, R.W.; Kern, J.; Piepenbring, R.; Boisson, J.P.
1984-09-07
A technique for modeling quasiparticle excitation energies and rotational parameters in odd-odd deformed nuclei has been applied to actinide species where new experimental data have been obtained by use of neutron-capture gamma-ray spectroscopy. The input parameters required for the calculation were derived from empirical data on single-particle excitations in neighboring odd-mass nuclei. Calculated configuration-specific values for the Gallagher-Moszkowski splittings were used. Calculated and experimental level structures for /sup 238/Np, /sup 244/Am, and /sup 250/Bk are compared, as well as those for several nuclei in the rare-earth region. The agreement for the actinide species is excellent, with bandhead energies deviating 22 keV and rotational parameters 5%, on the average. Corresponding average deviations for five rare-earth nuclei are 47 keV and 7%. Several applications of this modeling technique are discussed. 18 refs., 5 figs., 4 tabs.
Relativistic quasiparticle random phase approximation in deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Pena Arteaga, D.
2007-06-25
Covariant density functional theory is used to study the influence of electromagnetic radiation on deformed superfluid nuclei. The relativistic Hartree-Bogolyubov equations and the resulting diagonalization problem of the quasiparticle random phase approximation are solved for axially symmetric systems in a fully self-consistent way by a newly developed parallel code. Three different kinds of high precision energy functionals are investigated and special care is taken for the decoupling of the Goldstone modes. This allows the microscopic investigation of Pygmy and scissor resonances in electric and magnetic dipole fields. Excellent agreement with recent experiments is found and new types of modes are predicted for deformed systems with large neutron excess. (orig.)
Relativistic Quasiparticle Random Phase Approximation in Deformed Nuclei
Pena Arteaga, Daniel
2008-01-01
Covariant density functional theory is used to study the influence of electromagnetic radiation on deformed superfluid nuclei. The relativistic Hartree-Bogoliubov equations and the resulting diagonalization problem of the quasiparticle random phase approximation are solved for axially symmetric systems in a fully self-consistent way by a newly developed parallel code. Three different kinds of high precision energy functionals are investigated and special care is taken for the decoupling of th...
Proxy-SU(3) symmetry in heavy deformed nuclei
Bonatsos, Dennis; Assimakis, I. E.; Minkov, N.; Martinou, Andriana; Cakirli, R. B.; Casten, R. F.; Blaum, K.
2017-06-01
Background: Microscopic calculations of heavy nuclei face considerable difficulties due to the sizes of the matrices that need to be solved. Various approximation schemes have been invoked, for example by truncating the spaces, imposing seniority limits, or appealing to various symmetry schemes such as pseudo-SU(3). This paper proposes a new symmetry scheme also based on SU(3). This proxy-SU(3) can be applied to well-deformed nuclei, is simple to use, and can yield analytic predictions. Purpose: To present the new scheme and its microscopic motivation, and to test it using a Nilsson model calculation with the original shell model orbits and with the new proxy set. Method: We invoke an approximate, analytic, treatment of the Nilsson model, that allows the above vetting and yet is also transparent in understanding the approximations involved in the new proxy-SU(3). Results: It is found that the new scheme yields a Nilsson diagram for well-deformed nuclei that is very close to the original Nilsson diagram. The specific levels of approximation in the new scheme are also shown, for each major shell. Conclusions: The new proxy-SU(3) scheme is a good approximation to the full set of orbits in a major shell. Being able to replace a complex shell model calculation with a symmetry-based description now opens up the possibility to predict many properties of nuclei analytically and often in a parameter-free way. The new scheme works best for heavier nuclei, precisely where full microscopic calculations are most challenged. Some cases in which the new scheme can be used, often analytically, to make specific predictions, are shown in a subsequent paper.
Search for α + core states in even-even Cr isotopes
Energy Technology Data Exchange (ETDEWEB)
Souza, M.A. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil); Instituto Federal de Educacao, Ciencia e Tecnologia de Sao Paulo, Departamento de Mecanica, Sao Paulo, SP (Brazil); Miyake, H. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil)
2017-07-15
The α + core structure is investigated in even-even Cr isotopes from the viewpoint of the local potential model. The comparison of Q{sub α}/A values for even-even Cr isotopes and even-even A = 46, 54, 56, 58 isobars indicates that {sup 46}Cr and {sup 54}Cr are the most favorable even-even Cr isotopes for the α + core configuration. The ground state bands of the two Cr isotopes are calculated through a local α + core potential containing a nuclear term with (1 + Gaussian) x (W.S. + W.S.{sup 3}) shape. The calculated spectra give a very good description of most experimental {sup 46}Cr and {sup 54}Cr levels, including the 0{sup +} bandheads. The reduced α-widths, rms intercluster separations and B(E2) transition rates are determined for the ground state bands. The calculations reproduce the order of magnitude of the available experimental B(E2) values without using effective charges, indicate that the low-spin members of the ground state bands present a stronger α-cluster character, and point out that the {sup 46}Cr ground state band has a significant degree of α-clustering in comparison with {sup 44}Ti. The volume integral per nucleon pair and rms radius obtained for the α + {sup 50}Ti potential are consistent with those reported previously in the analysis of α elastic scattering on {sup 50}Ti. (orig.)
Fragmentation of two-phonon {gamma}-vibrational strength in deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Wu, C.Y.; Cline, D. [Univ. of Rochester, NY (United States)
1996-12-31
Rotational and vibrational modes of collective motion. are very useful in classifying the low-lying excited states in deformed nuclei. The rotational mode of collective motion is characterized by rotational bands having correlated level energies and strongly-enhanced E2 matrix elements. The lowest intrinsic excitation with I,K{sup {pi}} = 2,2{sup +} in even-even deformed nuclei, typically occurring at {approx}1 MeV, is classified as a one-phonon {gamma}-vibration state. In a pure harmonic vibration limit, the expected two-phonon {gamma}-vibration states with I,K{sup {pi}} = 0,0{sup +} and 4,4{sup +} should have excitation energies at twice that of the I,K{sup {pi}} = 2,2{sup +} excitation, i.e. {approx}2 MeV, which usually is above the pairing gap leading to possible mixing with two-quasiparticle configurations. Therefore, the question of the localization of two-phonon {gamma}-vibration strength has been raised because mixing may lead to fragmentation of the two-phonon strength over a range of excitation energy. For several well-deformed nuclei, an assignment of I,K{sup {pi}}=4,4{sup +} states as being two-phonon vibrational excitations has been suggested based on the excitation energies and the predominant {gamma}-ray decay to the I,K{sup {pi}}=2,2{sup +} state. However, absolute B(E2) values connecting the presumed two- and one-phonon states are the only unambiguous measure of double phonon excitation. Such B(E2) data are available for {sup 156}Gd, {sup 160}Dy, {sup 168}Er, {sup 232}Th, and {sup 186,188,190,192}Os. Except for {sup 160}Dy, the measured B(E2) values range from 2-3 Weisskopf units in {sup 156}Gd to 10-20 Weisskopf units in osmium nuclei; enhancement that is consistent with collective modes of motion.
Energy Technology Data Exchange (ETDEWEB)
Gastebois, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1968-06-01
The experimental results obtained in the study of the (d,p) reactions, at E{sub d} = 12 MeV, on the three even-even deformed nuclei {sup 170}Yb, {sup 172}Yb and {sup 174}Yb have been analysed in terms of DWBA calculations. The spectroscopic information relative to the odd final nuclei have been compared with the predictions of the collective model and of the Nilsson's model. The effect of various parameters used in the DWBA analysis (form factors, optical wave functions) has been carefully studied. The observed differences between the three final nuclei are qualitatively reproduced in the experimental study of resonances, seen in excitation functions of elastically and inelastically scattered protons on the same target nuclei, and corresponding to analogue states in the three nuclei {sup 171}Lu, {sup 173}Lu and {sup 175}Lu. (author) [French] Les resultats experimentaux de l'etude des reactions (d.p) a E{sub d} = 12 MeV, sur les noyaux deformes pairs-pairs {sup 170}Yb, {sup 172}Yb et {sup 174}Yb ont ete interpretes dans le cadre de l'approximation de Born des ondes deformees. Les informations spectroscopiques relatives aux noyaux impairs finals ont ete comparees aux predictions du modele collectif et du modele de Nilsson, apres avoir examine avec soin l'influence des differents parametres (facteurs de forme, fonctions d'onde 'optiques') utilises lors de l'analyse. Les differences observees entre les trois noyaux finals sont qualitativement reproduites par les resultats experimentaux de l'etude de resonances dans les fonctions d'excitation de diffusion elastique et inelastique de protons sur les memes noyaux-cibles, lors de la recherche d'etats analogues dans les noyaux {sup 171}Lu, {sup 173}Lu et {sup 175}Lu. (auteur)
Alpha Anisotropy Studies of Near-Spherical and Deformed Nuclei
Van Duppen, P
2002-01-01
% IS329 \\\\ \\\\ Although it was the first decay mode to be discovered, the process of $\\alpha$-particle emission is still poorly understood. A few years ago the first systematic study of anisotropic $\\alpha$-decay triggered renewed theoretical interest. Nevertheless, today the theories are still not adequate enough and more experimental data are urgently needed. We therefore measure the $\\alpha$-anisotropies of the favoured transitions of a number of near-spherical Rn and At isotopes, and of deformed nuclei near A=220. As the different models yield contradictory predictions for the transitions that are investigated, the measurements will allow to discern on their validity. They will at the same time provide the necessary basis for further theoretical developments.
Tunneling from super- to normal-deformed minima in nuclei.
Energy Technology Data Exchange (ETDEWEB)
Khoo, T. L.
1998-01-08
An excited minimum, or false vacuum, gives rise to a highly elongated superdeformed (SD) nucleus. A brief review of superdeformation is given, with emphasis on the tunneling from the false to the true vacuum, which occurs in the feeding and decay of SD bands. During the feeding process the tunneling is between hot states, while in the decay it is from a cold to a hot state. The {gamma} spectra connecting SD and normal-deformed (ND) states provide information on several physics issues: the decay mechanism; the spin/parity quantum numbers, energies and microscopic structures of SD bands; the origin of identical SD bands; the quenching of pairing with excitation energy; and the chaoticity of excited ND states at 2.5-5 MeV. Other examples of tunneling in nuclei, which are briefly described, include the possible role of tunneling in {Delta}I = 4 bifurcation in SD bands, sub-barrier fusion and proton emitters.
Deformation change in light iridium nuclei from laser spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Verney, D.; Le Blanc, F.; Obert, J.; Oms, J.; Puteaux, J.C.; Roussiere, B.; Sauvage, J. [IN2P3-CNRS/Universite Paris Sud-XI, Institut de Physique Nucleaire, Orsay Cedex (France); Cabaret, L.; Duong, H.T.; Pinard, J. [CNRS, Laboratoire Aime Cotton, Orsay Cedex (France); Crawford, J.E.; Lee, J.K.P. [McGill University, Physics Department, Montreal (Canada); Fricke, B.; Rashid, K. [Institut fuer Theoretische Physik der Universitaet Kassel, Kassel (Germany); Genevey, J.; Ibrahim, F. [IN2P3-CNRS/Universite Joseph Fourier-Grenoble I, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble Cedex (France); Huber, G.; Krieg, M.; Sebastian, V. [Institut fuer Physik der Universitaet Mainz, Mainz (Germany); Le Scornet, G.; Lunney, D. [IN2P3-CNRS/Universite Paris Sud-XI, Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Orsay Cedex (France)
2006-12-15
Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first transition of the ionization path 5d{sup 7}6s{sup 24}F{sub 9/2}{yields}5d{sup 7}6s6p{sup 6}F{sub 11/2} at 351.5nm were measured for {sup 182-189}Ir, {sup 186}Ir{sup m} and the stable {sup 191,193}Ir. The nuclear magnetic moments {mu}{sub I} and the spectroscopic quadrupole moments Q{sub s} were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of {mu}{sub I} was experimentally determined for the first time for the masses 182{<=}A{<=}189 and the isomeric state {sup 186}Ir{sup m}. The spectroscopic quadrupole moments of {sup 182}Ir and {sup 183}Ir were measured also for the first time. A large mean square charge radius change between {sup 187}Ir and {sup 186}Ir{sup g} and between {sup 186}Ir{sup m} and {sup 186}Ir{sup g} was observed corresponding to a sudden increase in deformation: from {beta}{sub 2}{approx_equal}+0.16 for the heavier group A = 193, 191, 189, 187 and 186m to {beta}{sub 2}{>=}+0.2 for the lighter group A=186g, 185, 184, 183 and 182. These results were analyzed in the framework of a microscopic treatment of an axial rotor plus one or two quasiparticle(s). This sudden deformation change is associated with a change in the proton state that describes the odd-nuclei ground state or that participates in the coupling with the neutron in the odd-odd nuclei. This state is identified with the {pi}3/2 {sup +}[402 ] orbital for the heavier group and with the {pi}1/2{sup -}[541 ] orbital stemming from the 1h
Structure of Even-Even 218-230 Ra Isotopes within the Interacting Boson Approximation Model
Diab S. M.
2008-01-01
A good description of the excited positive and negative parity states of radium nuclei (Z=88, N=130-142) is achieved using the interacting boson approximation model (IBA-1). The potential energy surfaces, energy levels, parity shift, electromagnetic transition rates B(E1), B(E2) and electric monopole strength X(E0/E2) are calculated for each nucleus. The analysis of the eigenvalues of the model Hamiltonian reveals the presence of an interaction between the positive and negative parity bands. ...
Microscopic description of the even-even 140-148Ba isotopes using BM, IBM and IVBM
Ahmed, Imad M.; Flaiyh, Ghaith N.; Kassim, Huda H.; Abdullah, Hewa Y.; Hossain, I.; Sharrad, Fadhil I.
2017-02-01
A description of the even-even Ba isotopes for A = 140 to 148 in framework of Bohr-Mottelson model, interacting boson model and interacting vector boson model are carried out. The E-GOS curve ( E γ/ I and the ratio between the energies of the ( I + 2) and ( I) states ( r( I + 2)/ I) as a function of the spin ( I have been drawn to determine the property of the ground-state band. The positive ground-state band of 140-148Ba has been calculated using Bohr-Mottelson model, interacting boson model and interacting vector boson model, while the negative-parity band of 140-148Ba has been calculated using Bohr-Mottelson model and interacting vector boson model only. The reduced transition probabilities B( E2) of these nuclei were calculated. The parameters of the best fit to the measured data are determined. The potential energy surfaces (PESs) to the IBM Hamiltonian have been obtained using the intrinsic coherent state.
Structure of Even-Even 218-230 Ra Isotopes within the Interacting Boson Approximation Model
Directory of Open Access Journals (Sweden)
Diab S. M.
2008-01-01
Full Text Available A good description of the excited positive and negative parity states of radium nuclei (Z=88, N=130-142 is achieved using the interacting boson approximation model (IBA-1. The potential energy surfaces, energy levels, parity shift, electromagnetic transition rates B(E1, B(E2 and electric monopole strength X(E0/E2 are calculated for each nucleus. The analysis of the eigenvalues of the model Hamiltonian reveals the presence of an interaction between the positive and negative parity bands. Due to this interaction the $Delta I = 1$ staggering effect, between the energies of the ground state band and the negative parity state band, is produced including beat patterns.
{Delta}I = 2 energy staggering in normal deformed dysprosium nuclei
Energy Technology Data Exchange (ETDEWEB)
Riley, M.A.; Brown, T.B.; Archer, D.E. [Florida State Univ., Tallahassee, FL (United States)] [and others
1996-12-31
Very high spin states (I{ge}50{Dirac_h}) have been observed in {sup 155,156,157}Dy. The long regular band sequences, free from sharp backbending effects, observed in these dysprosium nuclei offer the possibility of investigating the occurence of any {Delta}I = 2 staggering in normal deformed nuclei. Employing the same analysis techniques as used in superdeformed nuclei, certain bands do indeed demonstrate an apparent staggering and this is discussed.
Test of three-body contact Skyrme forces with spin excitations in deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Sarriguren, P. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia; Moya de Guerra, E. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia; Nojarov, R. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia
1997-03-01
Experimental data on spin M1 strength distributions in even-even rare-earth nuclei are compared to theoretical results of selfconsistent HF+RPA calculations with separable spin-spin residual interactions derived from the two alternative versions (two-body density-dependent and three-body contact terms) of the Skyrme force Sk3. It is shown that the two versions produce quite different spin M1 strength distributions, though they generate the same HF mean field. The experimental data favour the two-body over the three-body version of the Skyrme interactions Sk1-Sk6. (orig.)
The Discoveries of Bohrium, Hassium, Meitnerium, and the new Region of Deformed Shell Nuclei
Münzenberg, G
2003-01-01
The investigation of the light trans-actinide elements was not only exciting as it included the discovery of a number of new chemical elements. It led also to the discovery of a new region of shell nuclei existing beyond the macroscopic stability limit. Theory explained this in terms of a new shell region of deformed nuclei which bridge the trans-uranium nuclei and the predicted superheavy elements. This contribution will give a brief historic overview over these discoveries, experimental developments, and the impact on ongoing and future superheavy-element research.
Nasri, Amine; Dupuis, Marc; Blanchon, Guillaume; Bauge, Eric; Arellano, Hugo F.
2017-09-01
Direct reactions on deformed nuclei such as actinides are best studied with the coupled channel (CC) formalism and a complex coupling scheme. With all significant progress that has been made in describing target nuclei with mean field and beyond approaches, we can assess the scattering problem within CC framework using microscopic non local potentials. To undertake this challenging task, one needs a well-defined strategy. In this work, we describe our choices of interaction, of microscopic description of target nuclei and our numerical methods to solve CC equations with non local potentials. Motivations behind our choices are also presented.
Nasri, Amine; Dupuis, Marc; Blanchon, Guillaume; Bauge, Eric; Arellano, Hugo F.
2017-09-01
Direct reactions on deformed nuclei such as actinides are best studied with the coupled channel (CC) formalism and a complex coupling scheme. With all significant progress that has been made in describing target nuclei with mean field and beyond approaches, we can assess the scattering problem within CC framework using microscopic non-local potentials. To undertake this challenging task, one needs a well-defined strategy. In this work, we describe our choices of interaction, of microscopic description of target nuclei and our numerical methods to solve CC equations with non-local potentials. Motivations behind our choices are also presented.
Directory of Open Access Journals (Sweden)
Nasri Amine
2017-01-01
Full Text Available Direct reactions on deformed nuclei such as actinides are best studied with the coupled channel (CC formalism and a complex coupling scheme. With all significant progress that has been made in describing target nuclei with mean field and beyond approaches, we can assess the scattering problem within CC framework using microscopic non local potentials. To undertake this challenging task, one needs a well-defined strategy. In this work, we describe our choices of interaction, of microscopic description of target nuclei and our numerical methods to solve CC equations with non local potentials. Motivations behind our choices are also presented.
Theoretical description of low-lying K/sup. pi. / = 1/sup +/ states in deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Civitarese, O.; Faessler, A.; Nojarov, R.
1987-06-01
A systematic study of low-lying K/sup ..pi../ = 1/sup +/ states and M1 transitions has been performed for the deformed nuclei /sup 154/Sm, /sup 156/Gd, /sup 158/Gd /sup 164/Dy, /sup 168/Er, and /sup 174/Yb within the framework of the quasiparticle random phase approximation in axially symmetric deformed Woods-Saxon potentials. The model Hamiltonian includes a separable quadrupole-quadrupole spin-independent residual interaction. The theoretical results for 0/sup +/..-->..1/sup +/ M1 transitions in the rare-earth nuclei studied are shown to be in good agreement with the available experimental information.
Restoring force for the 1/sup +/ collective mode in deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Faessler, A.; Bochnacki, Z.; Nojarov, R.
1986-02-01
The restoring force for the isovector rotational oscillations is calculated for the deformed nuclei /sup 154/Sm, /sup 156/./sup 158/Gd, /sup 164/Er and /sup 174/Yb by expanding the symmetry energy in powers of the proton and neutron density deformations. Fairly good agreement with experimental energies of the 1/sup +/ state is obtained. The calculated B(M1)up values are about seven times larger than those observed experimentally.
Isovector M1 rotational states in deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Lipparini, E.; Stringari, S. (Trento Univ. (Italy). Dipartimento di Fisica)
1983-10-20
Isovector M1 rotational states are investigated in the framework of a sum rule approach. It is shown that, due to the nuclear deformation, the rotational isovector state couples to the k=/sup 1 +/ component of the isovector giant quadrupole resonance. The effect of the coupling on the energy and on the M1 strength of the low-lying state as well as the comparison with previous macroscopic and microscopic models are discussed in details. The analysis suggests the existence of a highly collective M1 state occurring at the energy ..omega..sub(M1)=56deltaAsup(-1/3) MeV.
Exotic octupole deformation in proton-rich Z=N nuclei
Energy Technology Data Exchange (ETDEWEB)
Takami, Satoshi; Yabana, K. [Niigata Univ. (Japan); Matsuo, M.
1998-03-01
We study static non-axial octupole deformations in proton-rich Z=N nuclei, {sup 64}Ge, {sup 68}Se, {sup 72}Kr, {sup 76}Sr, {sup 80}Zr and {sup 84}Mo, by using the Skyrme Hartree-Fock plus BCS method with no restrictions on the nuclear shape. The calculation predicts that the oblate ground state in {sup 68}Se is extremely soft for the Y{sub 33} triangular deformation, and that in {sup 80}Zr the low-lying local minimum state coexisting with the prolate ground state has the Y{sub 32} tetrahedral deformation. (author)
Deformation properties of the neutron-deficient ODD-A Pt and Hg nuclei
Energy Technology Data Exchange (ETDEWEB)
Sauvage, J.; Libert, J.; Roussiere, B.; Verney, D.; Ibrahim, F.; Le Blanc, F.; Oms, J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Cabaret, L.; Pinard, J. [Laboratoire Aime Cotton, 91 - Orsay (France); Crawford, J.E.; Lee, J.K.P. [Physics Dept., Mc Gill University, Montreal (Canada); Genevey, J. [Institut des Sciences Nucleaires, IN2P3-CNRS, 38 - Grenoble (France); Huber, G. [Institut fur Physik der Universitat Mainz (Germany)
2000-07-01
Nuclear and atomic spectroscopy measurements have provided a great number of data on the neutron-deficient Pt and Hg nuclei. The odd-A Pt and Hg with A<186 have a prolate shape, the even-even isotopes have a triaxial shape while the nuclear shape of the odd-A Pt and Hg with A>186 is still an open question. The energy of the low-lying levels and the nuclear moments have been calculated in the framework of a semi-microscopic axial-rotor + I quasiparticle coupling model. The predictions are compared with the experimental data and discussed. The results strongly suggest a prolate shape for the negative-parity low-lying states of the odd-A {sup 187-191}Pt and {sup 187-193}Hg isotopes. (authors)
E2 contributions to backward (e,e`) cross sections in heavy deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Dingfelder, M.; Nojarov, R.; Faessler, A. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik
1995-08-01
It is shown that E2 transitions to the rotational band of low lying M1 excitations in heavy deformed nuclei contribute to the M1 (e,e`) cross section at backward angles even at low incident energies of 50 MeV. The agreement with experiment is improved considerably, especially for intermediate transferred momenta, after taking the E2 contributions into account. (author).
Systematics of Absolute Gamma Ray Transition Probabilities in Deformed Odd-A Nuclei
Energy Technology Data Exchange (ETDEWEB)
Malmskog, S.G.
1965-11-15
All known experimentally determined absolute gamma ray transition probabilities between different intrinsic states of deformed odd-A nuclei in the rare earth, region (153 < A < 181) and in the actinide region (A {>=} 227) are compared with transition probabilities (Weisskopf and Nilsson estimate). Systematic deviations from the theoretical values are found. Possible explanations for these deviations are given. This discussion includes Coriolis coupling, {delta}K ={+-}2 band-mixing effects and pairing interaction.
Strongly Deformed Nuclear Shapes at Ultra-High Spin and Shape Coexistence in Nsim 90 Nuclei
Riley, M. A.; Aguilar, A.; Evans, A. O.; Hartley, D. J.; Lagergren, K.; Ollier, J.; Paul, E. S.; Pipidis, A.; Simpson, J.; Teal, C.; Twin, P. J.; Wang, X.; Appelbe, D. E.; Campbell, D. B.; Carpenter, M. P.; Clark, R. M.; Cromaz, M.; Darby, I. G.; Fallon, P.; Garg, U.; Janssens, R. V. F.; Joss, D. T.; Kondev, F. G.; Lauritsen, T.; Lee, I. Y.; Lister, C. J.; Macchiavelli, A. O.; Nolan, P. J.; Petri, M.; Rigby, S. V.; Thompson, J.; Unsworth, C.; Ward, D.; Zhu, S.; Ragnarsson, I.
2009-03-01
The N sim 90 region of the nuclear chart has featured prominently as the spectroscopy of nuclei at extreme spin has progressed. This talk will present recent discoveries from investigations of high spin behavior in the N sim 90 Er, Tm and Yb nuclei utilizing the Gammasphere gamma-ray spectrometer. In particular it will include discussion of the beautiful shape evolution and coexistence observed in these nuclei along with the identification of a remarkable new family of band structures. The latter are very weakly populated rotational sequences with high moment of inertia that bypass the classic terminating configurations near spin 40-50 hbar, marking a return to collectivity that extends discrete gamma -ray spectroscopy to well over 60 hbar. Establishing the nature of the yrast states in these nuclei beyond the oblate band-termination states has been a major goal for the past two decades. Cranking calculations suggest that these new structures most likely represent stable triaxial strongly deformed bands that lie in a valley of favored shell energy in deformation and particle-number space.
The Structure of Even-Even 218-230 Ra Isotopes within the Interacting Boson Approximation Model
Diab S. M.
2008-01-01
A good description of the excited positive and negative parity states of radium nuclei ( Z = 88, N = 130–142) is achieved using the interacting boson approximation model (IBA-1). The potential energy surfaces, energy levels, parity shift, electromagnetic tran- sition rates B ( E 1) , B ( E 2) and electric monopole strength X ( E 0 / E 2 ) are calculated for each nucleus. The analysis of the eigenvalues of the ...
Parity mixing in the single particle states of quadrupole-octupole deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Minkov, N; Drenska, S [Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Tzarigrad Road 72, BG-1784 Sofia (Bulgaria); Strecker, M; Scheid, W, E-mail: nminkov@inrne.bas.b [Institut fuer Theoretische Physik der Justus-Liebig-Universitaet, Heinrich-Buff-Ring 16, D-35392 Giessen (Germany)
2010-01-01
The effect of parity mixing in the single particle (s.p.) states of odd-mass nuclei with quadrupole-octupole deformations is examined through a reflection-asymmetric deformed shell model. A strong coupling scheme between the parity mixed s.p. state and a coherent quadrupole-octupole vibration mode in the core is considered. The Coriolis decoupling factor is obtained in a projected form corresponding to the good total parity of the system. The average parity of the s.p. state and the decoupling factor are evaluated in several nuclei as functions of the quadrupole and octupole deformation parameters {beta}{sub 2} and {beta}{sub 3}. It is found that the average s.p. parity obtains various dominant (+ or -) values in the ({beta}{sub 2},{beta}{sub 3})-plane, while the s.p. wave function is strongly fragmented into components with different parities. It is shown that by comparing the behaviour of the decoupling factor in the ({beta}{sub 2},{beta}{sub 3})-plane to values obtained in a collective quadrupole-octupole model one can determine physically reasonable regions for the deformation parameters.
The Structure of Even-Even 218-230 Ra Isotopes within the Interacting Boson Approximation Model
Directory of Open Access Journals (Sweden)
Diab S. M.
2008-01-01
Full Text Available A good description of the excited positive and negative parity states of radium nuclei ( Z = 88, N = 130–142 is achieved using the interacting boson approximation model (IBA-1. The potential energy surfaces, energy levels, parity shift, electromagnetic tran- sition rates B ( E 1 , B ( E 2 and electric monopole strength X ( E 0 / E 2 are calculated for each nucleus. The analysis of the eigenvalues of the model Hamiltonian reveals the presence of an interaction between the positive and negative parity bands. Due to this interaction the I = 1 staggering e ect, between the energies of the ground state band and the negative parity state band, is produced including beat patterns.
Deformation signature from the Gamow-Teller decay of N=Z nuclei
Miehé, C; Dessagne, P; Huck, A; Knipper, A; Marguier, G; Longour, C; Rauch, V; García-Borge, M J; Piqueras, I; Tengblad, O; Jokinen, A; Ramdhane, M
1998-01-01
The $^{76}$Sr (N=Z=38) and the $^{72}$Kr (N=Z=36)$\\beta^{+}$ EC decay have been studied at the CERN-ISOLDE PSB facility where their $\\beta-\\gamma$ and delayed particle decay modes have been investigated. The established decay schemes yield new information on the Gamow- Teller (GT) strength spread over the J$^{\\pi}$=1$^{+}$ states in the daughter nuclei. The delayed proton emission of an N=Z nucleus is observed for the first time in the case of $^{76}$Sr. The experimental GT strength intensities and distributions are discussed in the light of the theoretical estimates for oblate and prolate deformations. (6 refs).
Butler, P; Bastin, B; Kruecken, R; Voulot, D; Rahkila, P J; Orr, N A; Srebrny, J; Grahn, T; Clement, E; Paul, E S; Gernhaeuser, R A; Dorsival, A; Diriken, J V J; Huyse, M L; Iwanicki, J S
The neutron-deficient polonium isotopes with two protons outside the closed Z=82 shell represent a set of nuclei with a rich spectrum of nucleus structure phenomena. While the onset of the deformation in the light Po isotopes is well established experimentally, questions remain concerning the sign of deformation and the magnitude of the mixing between different configurations. Furthermore, controversy is present with respect to the transition from the vibrational-like character of the heavier Po isotopes to the shape coexistence mode observed in the lighter Po isotopes. We propose to study this transition in the even-mass neutron-deficient $^{198,200,202}$Po isotopes by using post-accelerated beams from REX-ISOLDE and "safe"-energy Coulomb excitation. $\\gamma$- rays will be detected by the MINIBALL array. The measurements of the Coulomb excitation differential cross section will allow us to deduce both the transition and diagonal matrix elements for these nuclei and, combined with lifetime measurements, the s...
Energy Technology Data Exchange (ETDEWEB)
Drenska, S.; Georgieva, A.; Minkov, N. [Bulgarian Academy of Sciences, Inst. for Nuclear Research and Nuclear Energy, Sofia (Bulgaria)
2002-12-01
We implement a high order discrete derivative analysis of the lowest nuclear collective excitations in terms of the quantum numbers of an algebraic Sp(4, R) classification scheme. The results reveal a fine systematic behavior of nuclear collectivity in terms of nucleon pairing and high order quartetting correlations. (author)
Nonadiabatic quasiparticle approach for deformed odd-odd nuclei and the proton emitter 130Eu
Patial, Monika; Arumugam, P.; Jain, A. K.; Maglione, E.; Ferreira, L. S.
2013-11-01
Proton emission from deformed nuclei near the drip line is regarded as a versatile tool in nuclear structure physics and such a study in odd-odd nuclei provides us with an excellent opportunity to understand several interesting features including the interaction between the valence proton and the valence neutron. We present a detailed formalism for a full microscopic calculation of such proton emitters, where the nuclear structure and decay aspects are taken into account exactly. This formalism is based on the nonadiabatic approach for the two quasiparticle plus rotor model, where the residual neutron-proton interactions are considered in the mean field represented by a deformed Woods-Saxon potential. We demonstrate a systematic way of unambiguously identifying several parameters involved in the calculations with the aid of the experimental data. The quality of results in the case of 180Ta justifies the approach which is further extended to discuss in detail the proton emission from 130Eu. Iπ=1+ state in 130Eu still remains to be the proton emitting state irrespective of the choice of several parameters. We also note that the decay widths could be quite sensitive to the residual np interaction in case of proton emission from isomeric states.
Spin- and deformation-dependent orbital M1 strength in rare-earth nuclei
Energy Technology Data Exchange (ETDEWEB)
Sarriguren, P.; Moya de Guerra, E. (Consejo Superior de Investigaciones Cientificas, Madrid (Spain). Inst. de Estructura de la Materia); Nojarov, R.; Faessler, A. (Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik)
1994-02-01
The M1 excitations in three isotope chains, [sup 142,146,148,150]Nd, [sup 144,148,150,152,154]Sm, and [sup 156,158]Gd, are studied within the quasi-particle random-phase approximation using a mean field given by a deformed Woods-Saxon potential and including quadrupole-quadrupole and spin-spin residual interactions. A residual rotation-vibration coupling ensures the exclusion of the spurious state. The behaviour of the M1 strength distribution is studied systematically in the whole range of experimentally explored excitation energies and compared with the large variety of experimental information. The double-peaked structure of the spin M1 strength distribution found experimentally in several nuclei is qualitatively reproduced and interpreted as isoscalar and isovector peaks. (author).
Energy Technology Data Exchange (ETDEWEB)
Ebran, J-P [CEA/DAM/DIF, F-91297 Arpajon (France); Khan, E; Arteaga, D Pena [Institut de Physique Nucleaire, University Paris-Sud, IN2P3-CNRS, F-91406 Orsay Cedex (France); Vretenar, D, E-mail: jean-paul.ebran@cea.fr [Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia)
2011-09-16
The Relativistic Hartree-Fock-Bogoliubov model for axially deformed nuclei (RHFBz) is presented. The model involves a phenomenological Lagrangian with density-dependent meson-nucleon couplings in the particle-hole channel and the central part of the Gogny force in the particle-particle channel. The RHFBz equations are solved by expansion in the basis of a deformed harmonic oscillator. Illustrative RHFBz calculations are performed for Neon isotopes.
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Nojarov, R.; Faessler, A.; Dingfelder, M. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)
1995-12-01
Important {ital E}2 contributions to the ({ital e},{ital e}{sup {prime}}) cross sections of low-lying orbital {ital M}1 excitations are found in heavy deformed nuclei, arising from the small energy separation between the two excitations with {ital I}{sup {pi}}{ital K}=2{sup +}1 and 1{sup +}1, respectively. They are studied microscopically in QRPA using DWBA. The accompanying {ital E}2 response is negligible at small momentum transfer {ital q} but contributes substantially to the cross sections measured at {theta}=165{degree} for 0.6{lt}{ital q}{sub eff}{lt}0.9 fm{sup {minus}1} (40{le}{ital E}{sub {ital i}}{le}70 MeV) and leads to a very good agreement with experiment. The electric response is of longitudinal {ital C}2 type for {theta}{le}175{degree} but becomes almost purely transverse {ital E}2 for larger backward angles. The transverse {ital E}2 response remains comparable with the {ital M}1 response for {ital q}{sub eff}{gt}1.2 fm{sup {minus}1} ({ital E}{sub {ital i}}{gt}100 MeV) and even dominant for {ital E}{sub {ital i}}{gt}200 MeV. This happens even at large backward angles {theta}{gt}175{degree}, where the {ital M}1 dominance is limited to the lower {ital q} region.
Spin response to backward (e,e{sup `}) scattering from heavy deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Nojarov, R. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Dingfelder, M. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik
1996-01-27
The M1 and E2 responses of spin 1{sup +} excitations to (e,e{sup `}) scattering from heavy deformed nuclei are studied in QRPA and DWBA on the example of {sup 158}Gd. The transverse response originates mainly from the magnetization currents. The transverse E2 dominates over the longitudinal C2 response for {theta}{>=}165 {sup circle}. The joint response of the whole spin-flip region (6-11 MeV) for {theta}{>=}165 {sup circle} is characterized by the M1 over E2 dominance for transferred momentum q{sub eff} < 0.6 fm{sup -1} (or incident electron energy E{sub i} < 40 MeV). Above these values the E2 response provides substantial contributions to the summed (e,e{sup `}) cross section. They are larger in the lower spin-flip region (6-8 MeV) due to the larger orbital (convection) contributions at lower excitation energy. (orig.).
Santhosh, K. P.; Sukumaran, Indu
2017-09-01
Half-life predictions have been performed for the proton emitters with Z >50 in the ground state and isomeric state using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The agreement of the calculated values with the experimental data made it possible to predict some proton emissions that are not verified experimentally yet. For a comparison, the calculations also are performed using other theoretical models, such as the Gamow-like model of Zdeb et al. [Eur. Phys. J. A 52, 323 (2016), 10.1140/epja/i2016-16323-7], the semiempirical relation of Hatsukawa et al. [Phys. Rev. C 42, 674 (1990), 10.1103/PhysRevC.42.674], and the CPPM of Santhosh et al. [Pramana 58, 611 (2002)], 10.1007/s12043-002-0019-2. The Geiger-Nuttall law, originally observed for α decay, studied for proton radioactivity is found to work well provided it is plotted for the isotopes of a given proton emitter nuclide with the same ℓ value. The universal curve is found to be valid for proton radioactivity also as we obtained a single straight line for all proton emissions irrespective of the parents. Through the analysis of the experimentally measured half-lives of 44 proton emitters, the study revealed that the present systematic study lends support to a unified description for studying α decay, cluster radioactivity, and proton radioactivity.
Gamow-Teller strength in deformed nuclei within self-consistent pnQRPA with the Gogny force
Directory of Open Access Journals (Sweden)
Martini M.
2014-03-01
Full Text Available In recent years fully consistent quasiparticle random-phase approximation (QRPA calculations using finite range Gogny force have been performed to study electromagnetic excitations of several axially-symmetric deformed nuclei up to the 238U. Here we present the extension of this approach to the charge-exchange nuclear excitations (pn-QRPA. In particular we focus on the Gamow-Teller (GT excitations. A comparison of the predicted GT strength distribution with existing experimental data is presented The role of nuclear deformation is shown. Special attention is paid to β-decay half-lives calculations for which experimental data exist.
Alternating-parity collective states of yrast and nonyrast bands in lanthanide and actinide nuclei
Energy Technology Data Exchange (ETDEWEB)
Nadirbekov, M. S., E-mail: nodirbekov@inp.uz; Yuldasheva, G. A. [Uzbek Academy of Sciences, Institute of Nuclear Physics (Uzbekistan); Denisov, V. Yu. [National Academy of Sciences of Ukraine, Institute for Nuclear Research (Ukraine)
2015-03-15
Excited collective states of even-even nuclei featuring quadrupole and octupole deformations are studied within a nonadiabatic collective model with a Gaussian potential energy. Rotational states of the yrast band and vibrational-rotational states of nonyrast bands are considered in detail. The energies of alternating-parity excited states of the yrast band in the {sup 164}Er, {sup 220}Ra, and {sup 224}Th nuclei; the yrast and first nonyrast bands in the {sup 154}Sm and {sup 160}Gd nuclei; and the yrast, first nonyrast, and second nonyrast bands in the {sup 224}Ra and {sup 240}Pu nuclei are described well on the basis of the proposed model.
Energy Technology Data Exchange (ETDEWEB)
Sarriguren, P.; Moya de Guerra, E.; Nojarov, R. [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, Serrano 119, E-28006 Madrid (Spain)
1996-08-01
We present a method to study spin magnetic dipole excitations in deformed nuclei within the quasiparticle random phase approximation based on self-consistent Hartree-Fock mean fields and residual interactions derived from the same effective two-body force. We perform a comprehensive study covering different Skyrme forces and various mass regions, and discussing the role of the mean field and of the residual interaction. An overall agreement with experimental data is obtained with the SG2 force. We study the systematics and the deformation dependence of the spin {ital M}1 strength distributions of {ital K}{sup {pi}}=1{sup +} excitations. It is found for the first time that the summed spin {ital M}1 strength obeys a quadratic dependence on deformation in the two isotope chains studied, {sup 142,146,148,150}Nd and {sup 144,148,150,152,154}Sm. {copyright} {ital 1996 The American Physical Society.}
Applications of mean-field plus nearest-orbit pairing interaction model to well-deformed nuclei
Chen Yu Yan
2002-01-01
An exactly solvable mean-field plus nearest-orbit pairing model for describing the well-deformed nuclei is adopted for study of the nuclei in rare-earth and actinide regions. Binding energies and pairing excitation energies of sup 1 sup 5 sup 8 sup - sup 1 sup 7 sup 1 Er, sup 1 sup 6 sup 0 sup - sup 1 sup 7 sup 8 Yb, sup 1 sup 7 sup 0 sup - sup 1 sup 8 sup 3 Hf, sup 2 sup 2 sup 6 sup - sup 2 sup 3 sup 4 Th, sup 2 sup 3 sup 0 sup - sup 2 sup 4 sup 0 U and sup 2 sup 3 sup 6 sup - sup 2 sup 4 sup 3 Pu isotopes are calculated and compared with the corresponding experimental results
Energy Technology Data Exchange (ETDEWEB)
Minkov, N [Institute of Nuclear Research and Nuclear Energy, 72 Tzarigrad Road, Sofia 1784 (Bulgaria); Yotov, P [Institute of Nuclear Research and Nuclear Energy, 72 Tzarigrad Road, Sofia 1784 (Bulgaria); Drenska, S [Institute of Nuclear Research and Nuclear Energy, 72 Tzarigrad Road, Sofia 1784 (Bulgaria); Scheid, W [Institut fuer Theoretische Physik der Justus-Liebig-Universitaet, Heinrich-Buff-Ring 16, D-35392 Giessen (Germany)
2006-04-01
We propose a collective model formalism which describes the strong parity shift observed in low-lying spectra of nuclei with octupole deformations together with the fine rotational band structure developed at higher-angular momenta. The parity effect is obtained by the Schroedinger equation for oscillations of the reflection asymmetric (octupole) shape between two opposite orientations in an angular momentum dependent double-well potential. The rotational structure is obtained by a collective quadrupole-octupole rotation Hamiltonian. The model scheme reproduces the complicated beat staggering patterns observed in the octupole bands of light actinide nuclei. It explains the angular momentum evolution of octupole spectra as the interplay between the octupole shape oscillation (parity shift) mode and the stable quadrupole-octupole rotation mode.
Energy Technology Data Exchange (ETDEWEB)
Rosse, B
2006-07-15
This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A {approx} 130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient Kr{sup 76} radioactive beam (T1/2 = 14.8 h). {gamma}-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first {gamma} transition was observed in the very exotic odd-odd Pm{sup 130} nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)
Energy Technology Data Exchange (ETDEWEB)
Hoff, R.W.; Gardner, D.G.; Gardner, M.A.
1985-05-01
A technique for modeling level structures of odd-odd nuclei has been used to construct sets of discrete states with energies in the range 0 to 1.5 MeV for several nuclei in the rare-earth and actinide regions. The accuracy of the modeling technique was determined by comparison with experimental data. Examination was made of what effect the use of these new, more complete sets of discrete states has on the calculation of level densities, total reaction cross sections, and isomer ratios. 9 refs.
Energy Technology Data Exchange (ETDEWEB)
Ha, Eunja; Cheoun, Myung-Ki [Soongsil University, Origin of Matter and Evolution of Galaxy Institute and Department of Physics, Seoul (Korea, Republic of)
2017-02-15
We investigated Gamow-Teller (GT) transitions and strength distributions of s-d shell N = Z nuclei, {sup 24}Mg, {sup 28}Si, and {sup 32}S, by a deformed quasi-particle random phase approximation (DQRPA). In the DQRPA, we included particle model space up to p-f shell and considered explicitly the deformation as well as the like- and unlike-pairing correlations. Shell evolution by deformation and attractive force by unlike-pairing correlations turned out to play vital roles to reproduce the experimental GT data. Correlations between the deformation and the pairing correlations are also discussed with the comparison to the experimental data shape. (orig.)
High-K isomers as probes of octupole collectivity in heavy nuclei
Energy Technology Data Exchange (ETDEWEB)
Walker, P.M., E-mail: p.walker@surrey.ac.u [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Minkov, N. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria)
2010-11-01
The influence of the octupole deformation on the structure of high-K isomeric states in the region of heavy even-even actinide nuclei is studied through a reflection asymmetric deformed shell model (DSM). Two-quasiparticle states with high-K values are constructed by taking into account the pairing effect through a DSM + BCS procedure with constant pairing interaction. The behaviour of two-quasiparticle energies and magnetic dipole moments of K{sup {pi}=}6{sup +}, 6{sup -} and 8{sup -} configurations, applicable to mass numbers in the range A=234-252, was examined over a wide range of quadrupole and octupole deformations. A pronounced sensitivity of the magnetic moments to the octupole deformation is found. The result suggests a possibly important role for high-K isomers in determining the degree of octupole deformation in heavy actinide nuclei.
Off-Yrast low-spin structure of deformed nuclei at mass number A∼150
Energy Technology Data Exchange (ETDEWEB)
Krugmann, Andreas
2014-07-14
The present work consists of two independent parts. The first part deals with the investigation of the 0{sup +}{sub 1}→0{sup +}{sub 2} transition in {sup 150}Nd with inelastic electron scattering and in the second part a proton scattering experiment for the investigation of dipole excitations is presented. In the first part of this thesis a pioneer experiment in inelastic electron scattering is introduced. At an electron energy of 75 MeV, excitation energy spectra have been measured at the high resolution 169 spectrometer at the S-DALINAC. The aim of this investigation was the determination of the ρ{sup 2}(E0;0{sup +}{sub 1}→0{sup +}{sub 2}) transition strength in the heavy deformed nucleus {sup 150}Nd. The experimental form factor of this particular transition has been compared to a theoretical form factor that has been constructed by an effective density operator on a microscopic level with the help of the generator coordinate method. The required collective wave functions have been calculated in the Confined β soft rotor model. In this model-dependent analysis the E0 transition strength has been determined for the first time. Furthermore the evolution of the E0 transition strength as a function of the potential stiffness has been investigated from the X(5) phase shape transitional point to the Rigid Rotor limit. It has been shown, that the E0 strength is relatively high at the shape-phase transitional point and starts to decrease with increasing stiffness and vanishes completely at the Rigid Rotor limit. Additionally the wave functions of the macroscopic collective Confined β-soft rotor model have been compared to those from a microscopic mean field Hamiltonian. Good agreement has been found. The second part of this thesis covers a polarized-proton scattering experiment on the heavy deformed nucleus {sup 154}Sm, that has been performed at the RCNP in Osaka, Japan. Utilizing the method of polarization transfer observables, a separation of spinflip and non
Interplay between tensor force and deformation in even–even nuclei
Energy Technology Data Exchange (ETDEWEB)
Bernard, Rémi N., E-mail: rbernard@ugr.es; Anguiano, Marta
2016-09-15
In this work we study the effect of the nuclear tensor force on properties related with deformation. We focus on isotopes in the Mg, Si, S, Ar, Sr and Zr chains within the Hartree–Fock–Bogoliubov theory using the D1ST2a Gogny interaction. Contributions to the tensor energy in terms of saturated and unsaturated subshells are analyzed. Like–particle and proton–neutron parts of the tensor term are independently examinated. We found that the tensor term may considerably modify the potential energy landscapes and change the ground state shape. We analyze too how the pairing characteristics of the ground state change when the tensor force is included.
Calculating Absolute Transition Probabilities for Deformed Nuclei in the Rare-Earth Region
Stratman, Anne; Casarella, Clark; Aprahamian, Ani
2017-09-01
Absolute transition probabilities are the cornerstone of understanding nuclear structure physics in comparison to nuclear models. We have developed a code to calculate absolute transition probabilities from measured lifetimes, using a Python script and a Mathematica notebook. Both of these methods take pertinent quantities such as the lifetime of a given state, the energy and intensity of the emitted gamma ray, and the multipolarities of the transitions to calculate the appropriate B(E1), B(E2), B(M1) or in general, any B(σλ) values. The program allows for the inclusion of mixing ratios of different multipolarities and the electron conversion of gamma-rays to correct for their intensities, and yields results in absolute units or results normalized to Weisskopf units. The code has been tested against available data in a wide range of nuclei from the rare earth region (28 in total), including 146-154Sm, 154-160Gd, 158-164Dy, 162-170Er, 168-176Yb, and 174-182Hf. It will be available from the Notre Dame Nuclear Science Laboratory webpage for use by the community. This work was supported by the University of Notre Dame College of Science, and by the National Science Foundation, under Contract PHY-1419765.
Energy Technology Data Exchange (ETDEWEB)
Hoff, R.W.; Jain, A.K.; Kvasil, J.; Sood, P.C.; Sheline, R.K. (Lawrence Livermore National Lab., CA (USA); Florida State Univ., Tallahassee, FL (USA))
1989-09-01
The application of a simple semi-empirical model is discussed in terms of interpreting experimental nuclear structure data for twelve of the best characterized odd-odd deformed nuclei. An essential part of this modeling is to calculate values for the Gallagher-Moszkowski splittings and Newby shifts, the observables that arise from the n-p residual interaction in odd-odd nuclei. Assumptions regarding the form for this n-p force are traced historically. The predictive power of a favored form of the n-p force, one that includes a central force with short and long-range components, a tensor force, and some effects of core polarization, is examined in light of experimental data obtained since its formulation. A data set of 42 experimentally determined Newby shifts has been reviewed as to the reliability of each entry. Exceptions to a recently proposed rule for the a priori determination of the sign of Newby shift are discussed. Evidence is presented for the existence of an odd-even staggering or signature effect in the rotational spacings of many K{sup {minus}} bands (with K > 0). By use of Coriolis-coupling calculations, it has been possible to reproduce the staggering observed in some of the K{sup {minus}} rotational bands of {sup 156}Tb, {sup 168}Tm, {sup 176}Lu, {sup 182}Ta, and {sup 182}Re. 27 refs., 3 figs., 3 tabs.
Studies of Stable Octupole Deformations in the Radium Region
2002-01-01
The purpose of the present project is to locate and identify states in the atomic nuclei possessing stable pearshaped octupole deformation. Such states, formally related to the structures known in molecular physics, manifest themselves as families of parity doublets in odd nuclei.\\\\ \\\\ The best possibilities for observing stable octupole deformations are offered in the Ra-region. Both theoretical calculations and experimental indications support such expectations. Such indications are the non-observation of two-phonon octupole vibrational states in the ISOLDE studies of the even-even radium nuclei, and the reversed sign of the decoupling factor of the ground state band in |2|2|5Ra observed in the single-neutron transfer reactions. In order to establish the predicted strong E1 and E3-transitions between the parity doublets in odd nuclei with stable octupole deformations it is proposed to study conversion electrons in odd-mass francium radium and radon isotopes following the @b-decay of francium and astatine. \\...
Symmetry energy and surface properties of neutron-rich exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Gaidarov, M. K.; Antonov, A. N. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Sarriguren, P. [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, E-28006 Madrid (Spain); Moya de Guerra, E. [Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)
2014-07-23
The symmetry energy, the neutron pressure and the asymmetric compressibility of spherical Ni, Sn, and Pb and deformed Kr and Sm neutron-rich even-even nuclei are calculated within the coherent density fluctuation model using the symmetry energy as a function of density within the Brueckner energy-density functional. The correlation between the thickness of the neutron skin and the characteristics related with the density dependence of the nuclear symmetry energy is investigated for isotopic chains of these nuclei in the framework of the deformed self-consistent mean-field Skyrme HF+BCS method. The mass dependence of the nuclear symmetry energy and the neutron skin thickness are also studied together with the role of the neutron-proton asymmetry. The studied correlations reveal a smoother behavior in the case of spherical nuclei than for deformed ones. We also notice that the neutron skin thickness obtained for {sup 208}Pb with SLy4 force is found to be in a good agreement with the recent data. In addition to the interest that this study may have by itself, we give some numerical arguments in proof of the existence of peculiarities of the studied quantities in Ni and Sn isotopic chains that are not present in the Pb chain.
Peninsulas of the neutron stability of nuclei in the vicinity of neutron magic numbers
Energy Technology Data Exchange (ETDEWEB)
Tarasov, V. N., E-mail: vtarasov@kipt.kharkov.ua [Kharkov Institute of Physics and Technology, National Science Center (Ukraine); Gridnev, K. A. [St. Petersburg State University, Fock Institute of Physics (Russian Federation); Greiner, W.; Gridnev, D. K. [Johann Wolfgang Goethe-Universitaet, Institut fuer Theoretische Physik (Germany); Kuprikov, V. I.; Tarasov, D. V. [Kharkov Institute of Physics and Technology, National Science Center (Ukraine); Vinas, X. [Universitat de Barcelona (Spain)
2012-01-15
On the basis of the Hartree-Fock method as implemented with Skyrme forces (Ska, SkM*, Sly4, and SkI2) and with allowance for an axial deformation and nucleon pairing in the Bardeen-Cooper-Schrieffer approximation, the properties of extremely neutron-rich even-even nuclei were calculated beyond the neutron drip line known earlier from theoretical calculations. It was shown that the chains of isotopes beyond the neutron drip line that contain N = 32, 58, 82, 126, and 184 neutrons form peninsulas of nuclei stable against the emission of one neutron and, in some cases, peninsulas of nuclei stable against the emission of two neutrons. The neutron- and proton-density distributions in nuclei forming stability peninsulas were found to be spherically symmetric. A mechanism via which the stability of nuclei might be restored beyond the neutron drip line was discussed. A comparison with the results of calculations by the Hartree-Fock-Bogolyubov method was performed for long chains of sulfur and gadolinium isotopes up to the neutron drip line.
Spectroscopy in neutron-rich nuclei in the vicinity of N=40
Energy Technology Data Exchange (ETDEWEB)
Braunroth, Thomas; Dewald, Alfred; Fransen, Christoph; Jolie, Jan; Litzinger, Julia [Institut fuer Kernphysik, Universitaet zu Koeln (Germany); Iwasaki, Hironori [National Superconducting Cyclotron Laboratory, MSU (United States)
2016-07-01
The development of collectivity towards N=40 in neutron-rich nuclei between {sub 20}Ca and {sub 28}Ni shows a distinct Z-dependence and is driven by subtle effects due to residual interactions. While {sup 68}Ni exhibits features of a pronounced shell-gap, the evolution of key observables, e.g. excitation energies and B(E2) values, in even-even {sub 26}Fe and {sub 24}Cr isotopes is interpreted as a rapidly evolving quadrupole deformation when N=40 is approached. However, experimental information on level energies and reduced transitions strengths are still sparse in this particular region of the nuclear landscape. To shed more light on the evolution of collectivity along even-even Cr isotopes towards N=40, we performed an experiment at NSCL, MSU (USA) in which lifetimes of excited states were measured with the recoil distance Doppler-shift technique. The experiment focused on the 2{sup +}{sub 1} and 4{sup +}{sub 1} states in {sup 58,60,62}Cr and corresponding results have been published recently. In addition, various excited states in neighbouring nuclei with 23
Macroscopic Properties of Nuclei within Self-Consistent and Liquid Drop Models
Nerlo-Pomorska, B.; Sykut, J.
2004-03-01
A set of parameters of the relativistic-mean-field theory (RMFT) is obtained by adjusting the macroscopic part of the RMFT binding energies of 142 spherical even-even nuclei to the phenomenological Lublin-Strasbourg-Drop (LSD) model.
Band coupling and crossing in nuclei
Energy Technology Data Exchange (ETDEWEB)
Nojarov, R. (Bylgarska Akademiya na Naukite, Sofia. Inst. za Yadrena Izsledvaniya i Yadrena Energetika; Sofia Univ. (Bulgaria). Fizicheski Fakultet); Nadjakov, E. (Joint Inst. for Nuclear Research, Dubna (USSR))
1983-03-28
A model of coupled rotational bands, including three types of phonons, ..beta.., ..gamma.. and S(Ksup(..pi..) = 1/sup +/ or O/sup +/), is proposed and applied to a number of even-even rare earth back-bending nuclei. It reproduces the most complicated experimentally known multiple-band crossings in /sup 154/Gd, /sup 156/Dy, /sup 164/Er and the clockwise circling of the yrast B(E2) values (versus ..omega../sup 2/) in back-bending nuclei. The direct coupling strengths, derived from a fit to experimental data, are discussed in detail.
Coulomb Excitation of Neutron-Rich $A\\approx$140 Nuclei
Van duppen, P L E
2002-01-01
Investigating the isospin dependence of the product between the B( E2; 0$_{1}^{+} \\rightarrow 2_{1}^{+}$)-value and the 2$_{1}^{+}$-excitation energy E$_{2^{+}}$ in even-even nuclei around $A\\!\\approx$140 one observes a rather smooth trend close to the valley of stability but clear indication for a reduction from the extrapolated B(E2)-values by one order of magnitude for some very neutron-rich nuclei. While close to the valley of stability the strong neutron-proton interaction results in an equilibration of the neutron and proton deformations with a predominate isoscalar character of the collective 2$^{+}$ excitation, it is conceivable that more loosely bound neutrons cannot polarize a close-to-magic proton core that well any more. This might result in a decoupling of the shape of the outer neutrons from the core and in a strong isovector admixture to the lowest lying 2$^{+}$ level. In this way the 2$^{+}$ -energies could be further lowered in neutron-rich nuclei, while the quadrupole moments of the proton c...
Directory of Open Access Journals (Sweden)
Dracoulis G.D.
2014-03-01
Full Text Available Recent results on high-spin isomers populated in deep-inelastic reactions in the transitional tungsten-osmium region are outlined with a focus on 190Os, 192Os and 194Os. As well as the characterization of several two-quasinutron isomers, the 12+ and 20+ isomers in 192Os are interpreted as manifestations of maximal rotation alignment within the neutron i13/2 and possibly proton h11/2 shells at oblate deformation.
International Symposium on Exotic Nuclei
Sobolev, Yu G; EXON-2014
2015-01-01
The production and the properties of nuclei in extreme conditions, such as high isospin, temperature, angular momenta, large deformations etc., have become the subject of detailed investigations in all scientific centers. The main topics discussed at the Symposium were: Synthesis and Properties of Exotic Nuclei; Superheavy Elements; Rare Processes, Nuclear Reactions, Fission and Decays; Experimental Facilities and Scientific Projects. This book provides a comprehensive overview of the newest results of the investigations in the main scientific centers such as GSI (Darmstadt, Germany), GANIL (Caen, France), RIKEN (Wako-shi, Japan), MSU (Michigan, USA), and JINR (Dubna, Russia).
Entropy in hot $^{161,162}Dy$ and $^{171,172}Yb$ nuclei
Guttormsen, M; Hjorth-Jensen, M; Melby, E; Rekstad, J; Schiller, A; Siem, S; Belic, A
2000-01-01
The density of accessible levels at low spin in the (^3He,\\alpha \\gamma) reaction has been extracted for the ^{161,162}Dy and ^{171,172}Yb nuclei. The entropy of the even-odd and even-even nuclei has been deduced as a function of excitation energy, and found to reach a maximum of 15 k_B before neutron evaporation. The entropy of one quasi-particle outside an even-even core is found to be 1.70(15) k_B. This quasi-particle picture of hot nuclei is well accounted for within a simple pairing model. The onset of two, four and six quasi-particle excitations in the ^{162}Dy and ^{172}Yb nuclei is discussed and compared to theory. The number of quasi-particles excited per excitation energy is a measure for the ratio of the level energy spacing and the pairing strength.
Onset of deformation in polonium nuclei
Energy Technology Data Exchange (ETDEWEB)
Younes, W.; Cizewski, J.A. [Rutgers Univ., New Brunswick, NJ (United States)
1996-12-31
The authors have been able to reproduce the systematics of the positive-parity states in {sup 192-208}Po within the framework of the Particle-Core Model. The wave-functions of the 2{sup +}{sub 1} states have been extracted using the Quasiparticle Random Phase Approximation. The increase in the collective motion of the lighter isotopes comes from the increased proton-neutron interaction when the neutrons and protons both occupy high-j orbitals.
Selfconsistent calculations for hyperdeformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Molique, H.; Dobaczewski, J.; Dudek, J.; Luo, W.D. [Universite Louis Pasteur, Strasbourg (France)
1996-12-31
Properties of the hyperdeformed nuclei in the A {approximately} 170 mass range are re-examined using the self-consistent Hartree-Fock method with the SOP parametrization. A comparison with the previous predictions that were based on a non-selfconsistent approach is made. The existence of the {open_quotes}hyper-deformed shell closures{close_quotes} at the proton and neutron numbers Z=70 and N=100 and their very weak dependence on the rotational frequency is suggested; the corresponding single-particle energy gaps are predicted to play a role similar to that of the Z=66 and N=86 gaps in the super-deformed nuclei of the A {approximately} 150 mass range. Selfconsistent calculations suggest also that the A {approximately} 170 hyperdeformed structures have neglegible mass asymmetry in their shapes. Very importantly for the experimental studies, both the fission barriers and the {open_quotes}inner{close_quotes} barriers (that separate the hyperdeformed structures from those with smaller deformations) are predicted to be relatively high, up to the factor of {approximately}2 higher than the corresponding ones in the {sup 152}Dy superdeformed nucleus used as a reference.
Electric monopole transitions from low energy excitations in nuclei
Wood, J L; De Coster, C; Heyde, Kris L G
1999-01-01
Electric monopole (E0) properties are studied across the entire nuclear mass surface. Besides an introductory discussion of various model results (shell model, geometric vibrational and rotational models, algebraic models), we point out that many of the largest E0 transition strengths, $\\rho^2$(E0), are associated with shape mixing. We discuss in detail the manifestation of E0 transitions and present extensive data for~: single-closed shell nuclei, vibrational nuclei, well-deformed nuclei, nuclei that exhibit sudden ground-state changes, and nuclei that exhibit shape coexistence and intruder states. We also give attention to light nuclei, odd-A nuclei, and illustrate a suggested relation between $\\rho^2$(E0) and isotopic shifts.
Extension of the consistent Q formalism to odd-A nuclei in the W-Pt region
Energy Technology Data Exchange (ETDEWEB)
Warner, D.D.; Van Isacker, P.; Jolie, J.; Bruce, A.M.
1984-01-01
It is shown that the approach of the Consistent Q Formalism, which has proved successful in the Interacting Boson Model description of even-even nuclei, can be extended to odd A nuclei within the framework of the Interacting Boson-Fermion Model. The proposed method describes the transition between the SU(3) and O(6) symmetry limits of the U(6/12) boson fermion group, and can be applied to the odd neutron W, Os, Pt nuclei. As in the even-even case, a number of parameter-free predictions emerge for the transitional region concerning energies, B(E2) values and also single particle structure factors, and some of these are compared to existing data for the odd Os nuclei. 15 references.
Energy Technology Data Exchange (ETDEWEB)
Huerstel, A
2002-11-01
This thesis is devoted to the study of very neutron deficient nuclei in the lead region of the nuclear chart and more precisely to the investigation of the single particle states and collective properties of the {sup 187,189}Bi isotopes by gamma-ray spectroscopy. These nuclei were produced via fusion-evaporation reaction induced by a krypton beam on a silver target. In this mass region, the cross section for producing these nuclei are very low, of the order of a few micro-barns, making experimental studies very difficult. The identification of the nuclei was done using the very powerful RDT (Recoil Decay Tagging) technique, based on the selection of the isotopes through their characteristic alpha-particle decays. The experiments were performed at the university of Jyvdskyla (Finland) with the facility combining the gamma-ray spectrometer JUROSPHERE and the magnetic gas-filled separator RITU. Isomeric states were observed in both nuclei and their life-times measured. The systematics of individual proton states in odd-mass bismuth isotopes have been reproduced with a shell model up to 20 neutrons away from the valley of stability. Furthermore, rotational bands, a signature of collective nuclear motion, have been established for the first time in these nuclei. The interpretation of these results led to the conclusion that {sup 187,189}Bi have a prolate shape at low excitation energy, unlike the heavier bismuth isotopes which have been interpreted to have oblate deformation, implying a shape transition in this mass region. Hartree-Fock-Bogolyubov calculations are consistent with the experimental indication of shape coexistence, as seen in the neighbouring even-even lead nuclei. (author)
Nuclear deformation at finite temperature.
Alhassid, Y; Gilbreth, C N; Bertsch, G F
2014-12-31
Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte Carlo method is used to generate a statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to temperatures higher than the spherical-to-deformed shape phase-transition temperature of mean-field theory.
Studies of pear-shaped nuclei using accelerated radioactive beams
Gaffney, L P; Scheck, M; Hayes, A B; Wenander, F; Albers, M; Bastin, B; Bauer, C; Blazhev, A; Bonig, S; Bree, N; Cederkall, J; Chupp, T; Cline, D; Cocolios, T E; Davinson, T; DeWitte, H; Diriken, J; Grahn, T; Herzan, A; Huyse, M; Jenkins, D G; Joss, D T; Kesteloot, N; Konki, J; Kowalczyk, M; Kroll, Th; Kwan, E; Lutter, R; Moschner, K; Napiorkowski, P; Pakarinen, J; Pfeiffer, M; Radeck, D; Reiter, P; Reynders, K; Rigby, S V; Robledo, L M; Rudigier, M; Sambi, S; Seidlitz, M; Siebeck, B; Stora, T; Thoele, P; Van Duppen, P; Vermeulen, M J; von Schmid, M; Voulot, D; Warr, N; Wimmer, K; Wrzosek-Lipska, K; Wu, C Y; Zielinska, M
2013-01-01
There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are ‘octupole deformed’, that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy, radioactive ions. Our data on and $^{224}$Ra show clear evidence for stronger octupole deformation in the latter. The results enable discrimination between differing theoretical approaches to octupole correlations, and help to constrain suitable candidates for experimental...
Decay properties of nuclei close to Z = 108 and N = 162
Energy Technology Data Exchange (ETDEWEB)
Dvorak, Jan
2007-07-12
The goal of the research conducted in the frame of this thesis was to investigate the decay properties of the nuclides {sup 269-271}Hs and their daughters using an improved chemical separation and detection system. Shell stabilization was predicted in the region around Z=108 and N=162 in calculations, taking into account possible higher orders of deformations of the nuclei. The nucleus {sup 270}Hs with a closed proton and a closed neutron deformed shell, was predicted to be ''deformed doubly magic''. Nuclei around {sup 270}Hs can be produced only via fusion reactions at picobarn levels, resulting in a production rates of few atoms per day. Investigating short-lived nuclei using rapid chemical separation and subsequent on-line detection methods provides an independent and alternative means to electromagnetic on-line separators. Chemical separation of Hs in the form of HsO{sub 4} provides an excellent tool to study the formation reactions and nuclear structure in this region of the chart of nuclides due to a high overall efficiency and a very high purification factor. The goal was accomplished, as element 108, hassium, was produced in the reaction {sup 248}Cm({sup 26}Mg,xn){sup 274-x}Hs and chemically isolated. After gas phase separation of HsO{sub 4}, 26 genetically linked decay chains have been observed. These were attributed to decays of three different Hs isotopes produced in the 3-5n evaporation channels. The known decay chain of {sup 269}Hs, the 5n evaporation product, serves as an anchor point, thus allowing the unambiguous assignment of the observed decay chains to the 5n, 4n, and 3n channels, respectively. Decay properties of five nuclei have been unambiguously established for the first time, including the one for the the doubly-magic nuclide {sup 270}Hs. This hassium isotope is the next doubly magic nucleus after the well known {sup 208}Pb and the first experimentally observed even-even nucleus on the predicted N=162 neutron shell. The
Spin, quadrupole moment, and deformation of the magnetic-rotational band head in (193)Pb
Balabanski, D L; Iordachescu, A; Bazzacco, D; Brandolini, F; Bucurescu, D; Chmel, S; Danchev, M; De Poli, M; Georgiev, G; Haas, H; Hubel, H; Marginean, N; Menegazzo, R; Neyens, G; Pavan, P; Rossi Alvarez, C; Ur, C A; Vyvey, K; Frauendorf, S
2011-01-01
The spectroscopic quadrupole moment of the T(1/2) = 9.4(5) ns isomer in (193)Pb at an excitation energy E(ex) = (2585 + x) keV is measured by the time-differential perturbed angular distribution method as vertical bar Q(s)vertical bar = 2.6(3) e b. Spin and parity I(pi) = 27/2(-) are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the coupling of a neutron hole in the 1i(13/2) subshell with the (3s(1/2)(-2)1h(9/2)1i(13/2))(11-) proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation epsilon(2) = -0.11, similar to that of the 11(-)proton intruder states, which occur in the even-even Pb nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.
Systematization of α-decaying nuclei based on shell structures: The case of even-odd nuclei
Energy Technology Data Exchange (ETDEWEB)
Yarman, Tolga [Okan University, Istanbul (Turkey); Zaim, Nimet [Trakya University, Edirne (Turkey); Yarman, O. [Istanbul University, Istanbul (Turkey); Kholmetskii, Alexander [Belarusian State University, Minsk (Belarus); Arik, Metin [Bogazici University, Istanbul (Turkey)
2017-01-15
Previously, we provided a novel systematization of α-decaying even-even nuclei starting with the classically adopted mechanism (Yarman et al., Eur. Phys. J. A 52, 140 (2016)). The decay half-life of an α-decaying nucleus was framed so that i) the α-particle is taken at the outset to be born inside the parent nucleus with a given probability, ii) where it then keeps on bouncing off of the barrier of the parent nucleus till iii) it finally tunnels through the barrier. Knowing beforehand the measured decay half-life, we have taken into consideration, as a parameter, the probability of the α-particle being first born within the parent before it is emitted. We thence developed a scaffold based on shell properties of families composed of alike even-even nuclei. Nevertheless, our model allows us to incorporate any α-decaying nuclei, and along this line, we present a follow-up systematization of even-odd nuclei, with cases of odd-even and odd-odd α-decaying nuclei pending to be considered in a separate contribution. Notwithstanding, we make an effort herein to expand our approach to investigate the effect of ''pairing'' (e.g., when a number of nucleons in the given nucleus becomes an even number, instead of the initial odd number, due to the addition of at least one neutron). Our results show that ''pairing'', as expected, definitely increases the stability of the given nucleus. (orig.)
Shell model for warm rotating nuclei
Energy Technology Data Exchange (ETDEWEB)
Matsuo, M.; Yoshida, K. [Kyoto Univ. (Japan); Dossing, T. [Univ. of Copenhagen (Denmark)] [and others
1996-12-31
Utilizing a shell model which combines the cranked Nilsson mean-field and the residual surface and volume delta two-body forces, the authors discuss the onset of rotational damping in normal- and super-deformed nuclei. Calculation for a typical normal deformed nucleus {sup 168}Yb indicates that the rotational damping sets in at around 0.8 MeV above the yrast line, and about 30 rotational bands of various length exists at a given rotational frequency, in overall agreement with experimental findings. It is predicted that the onset of rotational damping changes significantly in different superdeformed nuclei due to the variety of the shell gaps and single-particle orbits associated with the superdeformed mean-field.
Microscopic structure of high-spin vibrational states in superdeformed A=190 nuclei
Energy Technology Data Exchange (ETDEWEB)
Nakatsukasa, Takashi [Chalk River Labs., Ontario (Canada); Matsuyanagi, Kenichi [Kyoto Univ. (Japan); Mizutori, Shoujirou [Oak Ridge National Lab., TN (United States)] [and others
1996-12-31
Microscopic RPA calculations based on the cranked shell model are performed to investigate the quadrupole and octupole correlations for excited superdeformed (SD) bands in even-even A=190 nuclei. The K = 2 octupole vibrations are predicted to be the lowest excitation modes at zero rotational frequency. The Coriolis coupling at finite frequency produces different effects depending on the neutron and proton number of nucleus. The calculations also indicate that some collective excitations may produce moments of inertia almost identical to those of the yrast SD band. An interpretation of the observed excited bands invoking the octupole vibrations is proposed, which suggests those octupole vibrations may be prevalent in even-even SD A=190 nuclei.
Energy Technology Data Exchange (ETDEWEB)
Ripka, G. [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires
1968-09-01
Most of the content of this thesis is published in english in Advances In Nuclear Physics, Vol. 1 (Editors: Baranger and Vogt - Plenum Press). The Hartree- Fock equations are derived. The expansions of the orbits and the possible symmetries of the Hartree-Fock field are discussed. Wavefunctions of even-even N = Z nuclei are given for 12 {<=} A {<=} 40. The role of the monopole, quadrupole and exchange components of the force are discussed. The multiplicity of the solutions and the effect of the spin-orbit interaction are discussed. Exact angular momentum projection is used to generate rotational bands. The validity of the adiabatic rotational model in light nuclei is discussed. Hartree-Fock calculations are extended to include major-shell mixing in order to obtain quadrupole deformations without the use of effective charge. The incompressibility, of nuclei is discussed and the compatibility between the Hartree-Fock solutions, the Mottelson model of quadrupole deformations and the SU3 states of J.P. Elliott and M. Moshinsky is established. (author) [French] La theorie de Hartree-Fock est appliquee au calcul des fonctions d'onde des noyaux legers deformes. Les equations de Hartree-Fock, les symetries permises et le choix du developpement des orbites sont discutes. Les fonctions d'onde des noyaux pair-pairs N = Z (12 {<=} A {<=} 40) sont tabulees. Les contributions des composantes monopolaires et quadrupolaires ainsi que des termes d'echange de la force nucleon-nucleon sont discutees. La methode de projection de moment cinetique est utilisee pour engendrer les bandes de rotation. La validite du modele rotationnel adiabatique est discutee. Les calculs de Hartree-Fock qui tiennent compte du melange de plusieurs couches majeures dans chaque orbite sont appliques au calcul des deformations quadrupolaires sans l'utilisation de charge effective. L'incompressibilite des noyaux et la compatibilite des fonctions d'onde de Hartree- Fock avec les
Enhancement of octupole strength in near spherical nuclei
Energy Technology Data Exchange (ETDEWEB)
Robledo, L.M. [Universidad Autonoma de Madrid, Dep. Fisica Teorica, Facultad de Ciencias, Madrid (Spain)
2016-09-15
The validity of the rotational formula used to compute E1 and E3 transition strengths in even-even nuclei is analyzed within the Generator Coordinate Method framework based on mean field wave functions. It turns out that those nuclei with spherical or near spherical shapes the E1 and E3 strengths computed with this formula are strongly underestimated and a sound evaluation of them requires angular-momentum projected wave functions. Results for several isotopic chains with proton number equal to or near magic numbers are analyzed and compared with experimental data. The use of angular-momentum projected wave functions greatly improves the agreement with the scarce experimental data. (orig.)
Hexadecapole deformation studies in Nd
Indian Academy of Sciences (India)
[4] with only monopole and quadrupole degrees of freedom (sd-IBM) predicts a larger effective charge for neutrons ... in the SU(3) limit of sdg-IBM for axially symmetric deformed nuclei, M(E4) increases linearly with the .... dashed and dotted lines correspond to lower and upper β4 limits, respectively. Errors on data points ...
Silchenko, O. K.; Lipunov, V. M.
1985-12-01
In this paper the authors discuss observational and theoretical arguments in favour of hypothesis on "nomad life" of active nuclei inside and outside galaxies as well as its consequences. It may be the anisotropic collapse of a supermassive star, or the disruption of a supermassive binary system after the collapse of one companion that would give birth to such nuclei. The authors predict the existence of veritable quasi-stellar active objects without any ghost galaxies.
Alpha-cluster preformation factor within cluster-formation model for odd-A and odd-odd heavy nuclei
Saleh Ahmed, Saad M.
2017-06-01
The alpha-cluster probability that represents the preformation of alpha particle in alpha-decay nuclei was determined for high-intensity alpha-decay mode odd-A and odd-odd heavy nuclei, 82 CSR) and the hypothesised cluster-formation model (CFM) as in our previous work. Our previous successful determination of phenomenological values of alpha-cluster preformation factors for even-even nuclei motivated us to expand the work to cover other types of nuclei. The formation energy of interior alpha cluster needed to be derived for the different nuclear systems with considering the unpaired-nucleon effect. The results showed the phenomenological value of alpha preformation probability and reflected the unpaired nucleon effect and the magic and sub-magic effects in nuclei. These results and their analyses presented are very useful for future work concerning the calculation of the alpha decay constants and the progress of its theory.
Recent results on giant dipole resonance decays in highly excited nuclei
Energy Technology Data Exchange (ETDEWEB)
Snover, K.A.
1991-12-31
Some recent results on Giant Dipole Resonance (GDR) decays in highly excited, equilibrated nuclei, are discussed based primarily on work done at Seattle. Four sections address the following topics: oblate shapes of rotating, highly excited Zr--Mo nuclei; adiabatic versus `motionally narrowed` GDR decay; large spin-driven deformations observed in hot medium-mass nuclei; and search for entrance channel effects in GDR decay following {sup 58}Ni {plus} {sup 92}Zr fusion. 22 refs.
Recent results on giant dipole resonance decays in highly excited nuclei
Energy Technology Data Exchange (ETDEWEB)
Snover, K.A.
1991-01-01
Some recent results on Giant Dipole Resonance (GDR) decays in highly excited, equilibrated nuclei, are discussed based primarily on work done at Seattle. Four sections address the following topics: oblate shapes of rotating, highly excited Zr--Mo nuclei; adiabatic versus motionally narrowed' GDR decay; large spin-driven deformations observed in hot medium-mass nuclei; and search for entrance channel effects in GDR decay following [sup 58]Ni [plus] [sup 92]Zr fusion. 22 refs.
Nuclei and quantum worlds; Dans l'atome, des mondes quantiques
Energy Technology Data Exchange (ETDEWEB)
Chomaz, Ph
2000-07-01
This document gathers the slides and their commentaries that have been presented at the conference 'physics and fundamental questions' by P. Chomaz. The author reviews the different quantum aspects of nuclei: tunnel effect, symmetries, magic numbers, wave functions, size, shapes and deformations. The author shows that nuclei are quantum objects of great complexity, their structures are not yet well understood and the study of exotic nuclei will continue bringing valuable information.
Neutron-proton pairing correlations in medium mass N approx =Z nuclei
Petrovici, A; Faessler, A
1999-01-01
The pair structure and the average pairing gaps of realistic wave functions obtained within the complex Excited Vampir variational approach are investigated in order to evaluate the neutron-proton pairing correlations at low and high spins in medium mass N approx =Z nuclei. The number of isovector J suppi=0 sup + pairs is calculated for the lowest few 0 sup + states in two chains of nuclei in the A approx =70 mass region. The results indicate the dominant role played by the isovector neutron-proton pairing correlations in the structure of odd-odd N=Z nuclei and the reduction of their importance with increasing neutron excess in even-even nuclei. The evolution of particular isovector and isoscalar pairs with increasing angular momentum is analyzed for the odd-odd N=Z nucleus sup 7 sup 4 Rb and the even-even N=Z nucleus sup 7 sup 2 Kr. It turns out that in the nucleus sup 7 sup 4 Rb the neutron-proton correlations play an essential role for the alignment of the yrast positive-parity even-spin band.
Delayed and In-beam Spectroscopy on Francium and Astatine Nuclei at the Proton Drip Line
Energy Technology Data Exchange (ETDEWEB)
Uusitalo, J.; Jakobsson, U. [Department of Physics, University of Jyvaeskylae (Finland); Collaboration: RITU-Gamma Gollaboration
2011-11-30
Delayed and in-beam spectroscopy on francium and astatine nuclei at and beyond the proton drip line has been performed. In neutron deficient astatine nuclei a shift to deformed shapes as a function of decreasing neutron has been obtained. In neutron deficient francium isotope the same shift is evident.
Delayed and In-beam Spectroscopy on Francium and Astatine Nuclei at the Proton Drip Line
Uusitalo, J.; Jakobsson, U.
2011-11-01
Delayed and in-beam spectroscopy on francium and astatine nuclei at and beyond the proton drip line has been performed. In neutron deficient astatine nuclei a shift to deformed shapes as a function of decreasing neutron has been obtained. In neutron deficient francium isotope the same shift is evident.
Studies of pear-shaped nuclei using accelerated radioactive beams.
Gaffney, L P; Butler, P A; Scheck, M; Hayes, A B; Wenander, F; Albers, M; Bastin, B; Bauer, C; Blazhev, A; Bönig, S; Bree, N; Cederkäll, J; Chupp, T; Cline, D; Cocolios, T E; Davinson, T; De Witte, H; Diriken, J; Grahn, T; Herzan, A; Huyse, M; Jenkins, D G; Joss, D T; Kesteloot, N; Konki, J; Kowalczyk, M; Kröll, Th; Kwan, E; Lutter, R; Moschner, K; Napiorkowski, P; Pakarinen, J; Pfeiffer, M; Radeck, D; Reiter, P; Reynders, K; Rigby, S V; Robledo, L M; Rudigier, M; Sambi, S; Seidlitz, M; Siebeck, B; Stora, T; Thoele, P; Van Duppen, P; Vermeulen, M J; von Schmid, M; Voulot, D; Warr, N; Wimmer, K; Wrzosek-Lipska, K; Wu, C Y; Zielinska, M
2013-05-09
There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are 'octupole deformed', that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy, radioactive ions. Our data on (220)Rn and (224)Ra show clear evidence for stronger octupole deformation in the latter. The results enable discrimination between differing theoretical approaches to octupole correlations, and help to constrain suitable candidates for experimental studies of atomic electric-dipole moments that might reveal extensions to the standard model.
Electromagnetic structure of nuclei
Energy Technology Data Exchange (ETDEWEB)
Arnold, R.G.
1986-07-01
A brief review is given of selected topics in the electromagnetic structure of nucleons and nuclei, including nucleon form factors from both quantum chromodynamics and electron scattering data, measurements of the deuteron and triton form factors, quasi-elastic scattering, and the EMC effect. 47 refs., 13 figs. (LEW)
Sum rules and giant resonances in nuclei
Energy Technology Data Exchange (ETDEWEB)
Lipparini, E.; Stringari, S.
1989-04-01
The formalism of sum rules is developed and employed to investigate various giant resonances in nuclei. Particular emphasis is given to the role of surface effects which are shown to play a crucial role in the propagation of isoscalar as well as isovector collective modes. Sum rules for non-Hermitian operators, in particular for charge exchange reactions, are derived using the formalism of the dynamic polarizability. Several sum rules for investigating magnetic excitations, the structure of the transition density and the role of the nuclear deformation and of temperature on giant resonances are also presented and discussed.
Non-yrast split parity-doublet spectra in odd-mass nuclei
Energy Technology Data Exchange (ETDEWEB)
Strecker, Michael; Lenske, Horst [Institut fuer Theoretische Physik, Universitaet Giessen (Germany); Minkov, Nikolay [Institute of Nuclear Research and Nuclear Energy, Sofia (Bulgaria)
2013-07-01
We extend the coherent quadrupole and octupole model to describe non-yrast split parity-doublet bands in odd-A nuclei. It is shown that the model describes both the yrast and non-yrast quasi-parity doublet spectra and the related B(E1) and B(E2) transition rates in various odd-A nuclei from the rare-earth to the actinide region. As in case of even-even nuclei we make use of an analytically derived formula for the energies. The model parameters are adjusted in order to obtain the best description of the experiment. The observed Coriolis decoupling effects are taken into account phenomenologically. Results are compared to recent spectroscopic data.
Energy Technology Data Exchange (ETDEWEB)
Moretto, L.G.; Wozniak, G.J.
1988-11-01
The formation of hot compound nuclei in intermediate-energy heavy ion reactions is discussed. The statistical decay of such compound nuclei is responsible for the abundant emission of complex fragments and high energy gamma rays. 43 refs., 23 figs.
Structure Shape Evolution in Lanthanide and Actinide Nuclei
Directory of Open Access Journals (Sweden)
Khalaf A. M.
2013-04-01
Full Text Available To give the characteristics of the evolution of the collectivity in even-even nuclei, we studied the behavior of the energy ratios R(4 / 2 and R(6 / 4. All chains of lanthanides begins as vibrational with R(4 / 2 near 2.0 and move towards rotational (R(4 / 2 3.33 as neutron number increases. A rabid jump in R(4 / 2 near N = 90 was seen. The plot of R(4 / 2 against Z shows not only the existence of a shape transitions but also the change in curvature in the data for N = 88 and 90, concave to convex. For intermedi- ate structure the slopes in E-GOS ( E over spin plots range between the vibrator and rotor extremes. The abnormal behavior of the two-neutron separation energies of our lanthanide nuclei as a function of neutron number around neutron number 90 is cal- culated. Nonlinear behavior is observed which indicate that shape phase transition is occurred in this region. The calculated reduced B(E2 transition probabilities of the low states of the ground state band in the nuclei 150 Nd / 152 Sm / 154 Gd / 156 Dy are analyzed and compared to the prediction of vibrational U(5 and rotational SU(3 limits of interacting boson model calculations.
Energy Technology Data Exchange (ETDEWEB)
Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)
1998-07-22
For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.
Penionzhkevich, Yu. E.
2016-06-01
This work is an attempt to present some problems on the evolution of the Universe: the nucleosynthesis and cosmochronology from the standpoint of physics of particles and nuclei, in particular with the use of the latest results, obtained by means of radioactive nuclear beams. The comparison is made between the processes taking place in the Universe and the mechanisms of formation and decay of nuclei, as well as of their interaction at different energies. Examples are given to show the capabilities of nuclearphysics methods for studying cosmic objects and properties of the Universe. The results of investigations in nuclear reactions, induced by radioactive nuclear beams, make it possible to analyze the nucleosynthesis scenario in the region of light elements in a new manner.
Fission of heavy nuclei by linearly polarized photons
Khvastunov, V M; Kasyan, S V; Likhachev, V P; Paschuk, S A
2002-01-01
Analysing power SIGMA data from photofission of sup 2 sup 3 sup 2 Th, sup 2 sup 3 sup 3 U, sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 6 U, sup 2 sup 3 sup 8 U at the region of giant resonance have been measured using linearly polarized photons. The polarized photons were obtained by plane channelling of electrons in a silicon single crystal. The analysing power SIGMA dependence of the mass number of even-even nucleus has been discovered. Comparison of the analysing power SIGMA values with the data from other experiments with both polarized and unpolarized photon beams was made. It is shown that the analysing power SIGMA values agree with the modern knowledge of E1 transitions but cannot be explain by domination any one of them. It is supposed that analysing power SIGMA is very sensitive to different relative inner and outer fission barrier heights and this affects on SIGMA values for even-even nuclei with the same Z.
A simple model for doublet bands in doubly odd nuclei
Energy Technology Data Exchange (ETDEWEB)
Yoshinaga, N. [Saitama University, Department of Physics, Saitama City (Japan); Higashiyama, K. [Chiba Institute of Technology, Department of Physics, Narashino, Chiba (Japan); University of Tokyo, Department of Physics, Hongo, Tokyo (Japan)
2006-11-15
Nuclear structure of doublet bands in doubly odd nuclei with mass A {proportional_to} 130 is investigated within the framework of a simple model where the even-even core couples with a neutron and a proton in intruder orbitals through a quadrupole-quadrupole interaction. The model reproduces quite well the energy levels of doublet bands and electromagnetic transitions. The staggering of the ratios B(M1;I{yields}I-1)/B(E2;I{yields}I-2) of the yrast bands turns out to be described by the chopsticks-like motion of two angular momenta of the unpaired neutron and the unpaired proton when they are weakly coupled with the core. (orig.)
Sitter, de L.U.
1937-01-01
§ 1. Plastic deformation of solid matter under high confining pressures has been insufficiently studied. Jeffreys 1) devotes a few paragraphs to deformation of solid matter as a preface to his chapter on the isostasy problem. He distinguishes two properties of solid matter with regard to its
Energy Technology Data Exchange (ETDEWEB)
Liotta, R.J. [Royal Inst. of Tech. Stockholm (Sweden). Dept. of Solid State Electronics
1995-11-01
The Green function formalism is used to extend the standard (shell-model) treatment of bound states to processes that occur in the continuum part of nuclear spectra. The Berggren and Mittag-Leffler expansions are introduced and analysed. Applications to single-particle and particle-hole resonances are performed. Giant resonances are studied within the framework of the continuum RPA. In all cases it is found that the expansions agree well with the exact calculation. The mechanisms that induce the clustering of nucleons in nuclei are analysed and the corresponding decay processes are discussed in detail. (orig.)
Blandford, RD; Woltjer, L
1990-01-01
Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory
Beckmann, Volker
2012-01-01
This AGN textbook includes phenomena based on new results in the X-Ray domain from new telescopes such as Chandra and XMM Newton not mentioned in any other book. Furthermore, it considers also the Fermi Gamma Ray Space Telescope with its revolutionary advances of unprecedented sensitivity, field of view and all-sky monitoring. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. The book gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy d
Lappi, T
2010-01-01
This talk discusses some recent studies of gluon saturation in nuclei. We stress the connection between the initial condition in heavy ion collisions and observables in deep inelastic scattering (DIS). The dominant degree of freedom in the small x nuclear wavefunction is a nonperturbatively strong classical gluon field, which determines the initial condition for the glasma fields in the initial stages of a heavy ion collision. A correlator of Wilson lines from the same classical fields, known as the dipole cross section, can be used to compute many inclusive and exclusive observables in DIS.
Structure of exotic nuclei and superheavy elements in meson field theory
Energy Technology Data Exchange (ETDEWEB)
Linn, Khin Nyan
2008-07-15
In this work the nuclear structure of exotic nuclei and superheavy nuclei is studied in a relativistic framework. In the relativistic mean-field (RMF) approximation, the nucleons interact with each other through the exchange of various effective mesons (scalar, vector, isovector-vector). Ground state properties of exotic nuclei and superheavy nuclei are studied in the RMF theory with the three different parameter sets (ChiM,NL3,NL-Z2). Axial deformation of nuclei within two drip lines are performed with the parameter set (ChiM). The position of drip lines are investigated with three different parameter sets (ChiM,NL3,NL-Z2) and compared with the experimental drip line nuclei. In addition, the structure of hypernuclei are studied and for a certain isotope, hyperon halo nucleus is predicted. (orig.)
Band structure in doubly-odd nuclei with mass around 130
Energy Technology Data Exchange (ETDEWEB)
Higashiyama, K [Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); Yoshinaga, N [Department of Physics, Saitama University, Saitama City 338-8570 (Japan)
2006-10-10
Nuclear structure of the doublet bands in the doubly-odd nuclei with mass A {approx} 130 is studied in terms of a pair-truncated shell model. The model reproduces quite well the energy levels of the doublet bands and the electromagnetic transitions. The doublet bands turn out to be realized by the chopsticks-like motion of two angular momenta of the unpaired neutron and the unpaired proton, weakly coupled with the quadrupole collective excitations of the even-even part of the nucleus.
Toroidal Nuclear Matter Distributions of Superheavy Nuclei from Constrained Skyrme-HFB Calculations
Energy Technology Data Exchange (ETDEWEB)
Kosior, Amelia [Maria Curie-Sklodowska University, Poland; Staszczak, A. [Maria Curie-Sklodowska University, Poland; Wong, Cheuk-Yin [ORNL
2017-01-01
Using the Hartree Fock Bogoliubov (HFB) self-consistent mean-field theory with the SkM* Skyrme energy-density functional, we study nuclear structure properties of even even superheavy nuclei (SHN) of Z = 120 isotopes and N = 184 isotones. The shape of the nucleus along the lowest energy curve as a function of the quadrupole moment Q20 makes a sud- den transition from the oblate spheroids (biconcave discs) to the toroidal shapes, in the region of large oblate quadrupole moments.
Deformity - contracture ... Contracture can be caused by any of the following: Brain and nervous system disorders, such as cerebral ... Follow your health care provider's instructions for treating contracture at home. Treatments may include: Doing exercises and ...
Cold fission from isomeric states of superheavy nuclei
Sandulescu, A.; Mirea, M.
2014-07-01
Correlations between the potential energy surface structure and the mass distributions observed in the production of superheavy nuclei are evidenced. The isomeric states are identified by spanning the multidimensional configuration space from the contact point of the colliding nuclei up to the formation of the compound nucleus. The available degrees of freedom are the elongation, the necking, the mass asymmetry, and the deformations of the two colliding nuclei. Using the macroscopic-microscopic model based on the Woods-Saxon two-center shell model, several minima in the potential energy landscape were revealed. The fission process from these isomeric states was investigated and the probabilities of realization of possible partitions were calculated in the WKB approximation. The inertia was computed in the framework of the cranking model. The identified correlations indicate that the mass distribution attributed to quasifission in previous studies can be alternatively explained as a cold-fission process from excited states.
Study of fp States in Nuclei with High Neutron Excess
2002-01-01
Previous results obtained at ISOLDE on GT transitions in n-rich Na and Mg nuclei have shown the sharp decrease of excitation energy for fp states when A$>$29. \\\\ \\\\ Independently, shell model calculations have revealed that the onset of a deformation region near N=20 for Ne, Na and Mg nuclei was related to a sudden transition in the ground state properties with the appearance of a major (sd)$^{-2}$(fp)$^2$ component. \\\\ \\\\ We propose to use the new possibilities of producing and detecting n-rich nuclei to study by $\\gamma$ and n spectroscopy the properties of fp states with different cores: around N=20 (Na, Mg and Al) and N=28 (Ar, K and Ca). In particular, the cases of $^3
Shape transition in odd-odd A [approx] 130 nuclei
Energy Technology Data Exchange (ETDEWEB)
Rizzutto, M.A. (Lab. Pelletron, Dept. de Fisica Nuclear, Inst. de Fisica, Univ. de Sao Paulo, Sao Paolo, SP (Brazil)); Cybulska, E.W. (Lab. Pelletron, Dept. de Fisica Nuclear, Inst. de Fisica, Univ. de Sao Paulo, Sao Paolo, SP (Brazil)); Emediato, L.G.R. (Lab. Pelletron, Dept. de Fisica Nuclear, Inst. de Fisica, Univ. de Sao Paulo, Sao Paolo, SP (Brazil)); Medina, N.H. (Lab. Pelletron, Dept. de Fisica Nuclear, Inst. de Fisica, Univ. de Sao Paulo, Sao Paolo, SP (Brazil)); Ribas, R.V. (Lab. Pelletron, Dept. de Fisica Nuclear, Inst. de Fisica, Univ. de Sao Paulo, Sao Paolo, SP (Brazil)); Hara, K. (Lab. Pelletron, Dept. de Fisica Nuclear, Inst. de Fisica, Univ. de Sao Paulo, Sao Paolo, SP (Brazil)); Lima, C.L. (Nuclear Theory and Elementary Particle Phenomenology Group, Inst. de Fisica, Univ. de Sao Paulo, Sao Paulo, SP (Brazil))
1994-03-14
A systematic analysis of rotational bands in doubly odd nuclei in the mass region A = 130-140 is carried out using a shell model configuration mixing approach. The shell model (many-body) basis is constructed by projecting out deformed quasiparticle (Nilsson + BCS) states onto good angular momenta. The hamiltonian is assumed to be a sum of (spherical) single-particle hamiltonian and a schematic two-body interaction, which consists of Q.Q + (monopole) pairing + quadrupole-pairing forces. The analysis indicates a shape transition from prolate (N = 73) to oblate (N = 79) shape as a function of neutron number. Agreement between theoretical results and experimental data is quite satisfactory except for [gamma]-deformed nuclei (N = 75 and 77). (orig.)
Collective excitations in nuclei
Energy Technology Data Exchange (ETDEWEB)
Chomaz, Ph. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)
1998-12-31
The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors) 304 refs., 53 figs., 5 tabs.
A microscopic multiphonon approach to even and odd nuclei
De Gregorio, G.; Knapp, F.; Lo Iudice, N.; Veselý, P.
2017-07-01
The formalism of an equation of motion phonon method is briefly outlined. In even-even nuclei, the method derives equations of motion which generate an orthonormal basis of correlated n-phonon states (n = 0, 1, 2, ...), built of constituent Tamm-Dancoff phonons, and, then, solves the nuclear eigenvalue problem in such a multiphonon basis. In odd nuclei, analogous equations yield a basis of correlated orthonormal multiphonon particle-core states to be used for the solution of the full eigenvalue equations. The formalism does not rely on approximations, but lends itself naturally to simplifying assumptions. As illustrated here, the method has been implemented numerically for studying the electric dipole response in the heavy neutron rich 208Pb and 132Sn and in the odd 17O and 17F. Self-consistent calculations, using a chiral inspired Hamiltonian, have confirmed the important role of the multiphonon states in enhancing the fragmentation of the strength in the giant and pygmy resonance regions consistently with the experimental data.
Structure and symmetries of odd-odd triaxial nuclei
Energy Technology Data Exchange (ETDEWEB)
Palit, R. [Tata Institute of Fundamental Research, Department of Nuclear and Atomic Physics, Colaba, Mumbai (India); Bhat, G.H. [University of Kashmir, Department of Physics, Srinagar (India); Govt. Degree College Kulgam, Department of Physics, Kulgam (India); Sheikh, J.A. [University of Kashmir, Department of Physics, Srinagar (India); Cluster University of Srinagar, Srinagar, Jammu and Kashmir (India)
2017-05-15
Rotational spectra of odd-odd Rh and Ag isotopes are investigated with the primary motivation to search for the spontaneous chiral symmetry breaking phenomenon in these nuclei. The experimental results obtained on the degenerate dipole bands of some of these isotopes using a large array of gamma detectors are discussed and studied using the triaxial projected shell (TPSM) approach. It is shown that, first of all, to reproduce the odd-even staggering of the known yrast bands of these nuclei, large triaxial deformation is needed. This large triaxial deformation also gives rise to doublet band structures in many of these studied nuclei. The observed doublet bands in these isotopes are shown to be reproduced reasonably well by the TPSM calculations. Further, the TPSM calculations for neutron-rich nuclei indicate that the ideal manifestation of the chirality can be realised in {sup 106}Rh and {sup 112}Ag, where the doublet bands have similar electromagnetic properties along with small differences in excitation energies. (orig.)
Rotational alignment in soft nuclei
Energy Technology Data Exchange (ETDEWEB)
Nojarov, R. (Bylgarska Akademiya na Naukite, Sofia. Inst. po Yadrena Fizika i Yadrena Energetika)
1983-12-08
It is shown that in transitional odd-A nuclei, where the rotation-aligned coupling scheme usually takes place, the low collective angular momentum states of the decoupled band are not completely aligned due to core softness. This is illustrated on the example of La-nuclei.
Spectroscopy of heavy fissionable nuclei
Indian Academy of Sciences (India)
2015-08-05
Aug 5, 2015 ... Structural studies of heavy nuclei are quite challenging due to increased competition from fission, particularly at high spins. Nuclei in the actinide region exhibit a variety of interesting phenomena. Recent advances in instrumentation and analysis techniques have made feasible sensitive measurements of ...
Electron scattering for exotic nuclei
Indian Academy of Sciences (India)
2014-11-04
Nov 4, 2014 ... determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision ... Electron scattering of highly unstable nuclei is not easy because it is difficult to produce ... both ends form a mirror potential to keep the ions longitudinally inside the SCRIT device, and the ...
Cavitation inception from bubble nuclei
DEFF Research Database (Denmark)
Mørch, Knud Aage
2015-01-01
. The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model......The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years......, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid...
Directory of Open Access Journals (Sweden)
Holt Roy J.
2016-01-01
Full Text Available Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.
Coexistence in even-mass nuclei
Energy Technology Data Exchange (ETDEWEB)
Wood, J.L. (Georgia Inst. of Tech., Atlanta, GA (United States). School of Physics); Heyde, K. (Inst. for Theoretical Physics and Inst. for Nuclear Physics, Ghent (Belgium)); Nazarewicz, W. (Joint Inst. for Heavy-Ion Research, Oak Ridge, TN (United States). Holifield Heavy-Ion Research Facility Warsaw Univ. (Poland). Inst. of Theoretical Physics); Huyse, M.; Duppen, P. van (Katholieke Univ., Leuven (Belgium). Inst. voor Kern- en Stralingsfysika)
1992-06-01
Shape coexistence in doubly even nuclei is reviewed. Two main theoretical approaches are presented. The first is essentially the shell model with the excitation of pairs of protons and/or neutrons across closed shells or subshells together with a residual proton-neutron interaction. The second is the deformed mean-field approach. The first is broadly defined so that it includes various truncation schemes to the shell model including generalized seniority and the interacting boson model. The presentation of the theory has two main aims: to provide a framework into which the majority of theoretical studies of shape coexistence can be placed and to provide a framework within which a unified view can be discussed. Selected experimental data are shown from {sup 16}O to {sup 238}U. Our criteria for selection emphasize detailed spectroscopic evidence ('fingerprints') for coexisting shapes. (orig.).
Masses and radii of spherical nuclei calculated in various microscopic approaches
Energy Technology Data Exchange (ETDEWEB)
Patyk, Z.; Sobiczewski, A. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Soltan Inst. for Nuclear Studies, Warsaw (Poland); Baran, A. [Uniwersytet Marii Curie-Sklodowskiej, Lublin (Poland). Inst. Fizyki; Berger, J.F.; Decharge, J. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France); Dobaczewski, J. [Warsaw Univ. (Poland). Inst. Fizyki Teoretycznej; Ring, P. [Technische Univ. Muenchen, Garching (Germany). Physik-Department
1997-08-01
The quality of the description of nuclear masses and charge radii, calculated in various microscopic approaches, is studied. The Hartree-Fock-Bogoliubov (HFB), extended Thomas-Fermi model with Strutinski integral (ETFSI), relativistic mean field (RMF) and macroscopic-microscopic(MM) approaches are considered. In the HFB approximation, both finite-range (Gogny) and zero-range (Skyrme) effective forces are used. Spherical even-even nuclei (116 nuclides), from light (A=16) to heavy (A=220) ones, with known experimental mass are chosen for the study. A general result is that the best description of masses of considered nuclei is obtained in the MM and ETFSI approaches, while the best charge radii are obtained within the RMF and ETFSI approximations. The behaviour of nuclear masses and radii, when one moves far off the {beta}-stability line, is also studied. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Robertson, R.G.H.
1980-01-01
A summary of parity violating effects in nuclei is given. Thanks to vigorous experimental and theoretical effort, it now appears that a reasonably well-defined value for the weak isovector ..pi..-nucleon coupling constant can be obtained. There is one major uncertainty in the analysis, namely the M2/E1 mixing ratio for the 2.79 MeV transition in /sup 21/Ne. This quantity is virtually impossible to calculate reliably and must be measured. If it turns out to be much larger than 1, then a null result in /sup 21/Ne is expected no matter what the weak interaction, so an experimental determination is urgently needed. The most promising approach is perhaps a measurement of the pair internal conversion coefficient. Of course, a direct measurement of a pure isovector case is highly desirable, and it is to be hoped that the four ..delta..T = 1 experiments will be pushed still further, and that improved calculations will be made for the /sup 6/Li case. Nuclear parity violation seems to be rapidly approaching an interesting and useful synthesis.
Energy Technology Data Exchange (ETDEWEB)
Ayala, A.L. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica][Pelotas Univ., RS (Brazil). Inst. de Fisica e Matematica; Ducati, M.B.G. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Levin, E.M. [Fermi National Accelerator Lab., Batavia, IL (United States)][Nuclear Physics Inst., St. Petersburg (Russian Federation)
1996-10-01
In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab.
Collective excitations in nuclei
Energy Technology Data Exchange (ETDEWEB)
Chomaz, Ph
1997-12-31
The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author) 270 refs.
Energy Technology Data Exchange (ETDEWEB)
Barloutaud, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1958-06-15
The following nuclei were excited by protons of 5 MeV maximum energy: {sup 182}W - {sup 184}W - {sup 186}W - {sup 186}Os - {sup 188}Os - {sup 189}Os - {sup 190}Os - {sup 192}Os - {sup 194}Pt - {sup 196}Pt - {sup 198}Pt - {sup 198}Hg - {sup 200}Hg - {sup 202}Hg - {sup 204}Hg - {sup 206}Pb. The reduced probabilities of the various transitions were deduced from the coulomb excitation cross-section measurements. For some even-even nuclei two 2 + levels were excited. The properties of the excited levels are interpreted in terms of the collective model. (author) [French] Au moyen de protons d'energie inferieure a 5 MeV, l'excitation coulombienne des noyaux suivants a ete etudiee: {sup 182}W - {sup 184}W - {sup 186}W - {sup 186}Os - {sup 188}Os - {sup 189}Os - {sup 190}Os - {sup 192}Os - {sup 194}Pt - {sup 196}Pt - {sup 198}Pt - {sup 198}Hg - {sup 200}Hg - {sup 202}Hg - {sup 204}Hg - {sup 206}Pb. La mesure de la section efficace d'excitation coulombienne a permis de deduire les -probabilites reduites des diverses transitions observees. Dans certains noyaux pair-pair, deux niveaux de caractere 2 + ont ete excites. L'interpretation de ces niveaux en termes de niveaux de rotation et de niveaux de vibration a l'aide du modele collectif est discutee. En particulier, la variation des proprietes de ces niveaux avec la deformation nucleaire permet de fixer des limites a la validite des diverses hypotheses entrant dans le modele collectif. (auteur)
A nucleon-pair and boson coexistent description of nuclei
Dai, Lianrong; Pan, Feng; Draayer, J. P.
2017-07-01
We study a mixture of s-bosons and like-nucleon pairs with the standard pairing interaction outside an inert core. Competition between the nucleon-pairs and s-bosons is investigated in this scenario. The robustness of the BCS-BEC coexistence and crossover phenomena are examined through an analysis of pf-shell nuclei with realistic single-particle energies, in which two configurations with Pauli blocking of nucleon-pair orbits due to the formation of the s-bosons is taken into account. When the nucleon-pair orbits are considered to be independent of the s-bosons, the BCS-BEC crossover becomes smooth, with the number of the s-bosons noticeably more than that of the nucleon-pairs near the half-shell point, a feature that is demonstrated in the pf-shell for several values of the standard pairing interaction strength. As a further test of the robustness of the BCS-BEC coexistence and crossover phenomena in nuclei, results are given for values of even-even 102-130Sn with 100Sn taken as a core and valence neutron pairs confined within the 1d 5/2, 0g 7/2, 1d 3/2, 2s 1/2, 1h 11/2 orbits in the nucleon-pair orbit and the s-boson independent approximation. The results indicate that the B(E2) values are reproduced well. Supported by National Natural Science Foundation of China (11375080, 11675071), the U.S. National Science Foundation (OCI-0904874 and ACI-1516338), U. S. Department of Energy (DE-SC0005248), the Southeastern Universities Research Association, the China-U. S. Theory Institute for Physics with Exotic Nuclei (CUSTIPEN) (DE-SC0009971), and the LSU-LNNU joint research program (9961) is acknowledged
DEFF Research Database (Denmark)
Hansen, N.; Huang, X.; Hughes, D.A.
2004-01-01
Microstructural characterization and modeling has shown that a variety of metals deformed by different thermomechanical processes follows a general path of grain subdivision, by dislocation boundaries and high angle boundaries. This subdivision has been observed to very small structural scales...... of the order of 10 nm, produced by deformation under large sliding loads. Limits to the evolution of microstructural parameters during monotonic loading have been investigated based on a characterization by transmission electron microscopy. Such limits have been observed at an equivalent strain of about 10...
Shape-phase transitions in odd-mass γ -soft nuclei with mass A ≈130
Nomura, K.; Nikšić, T.; Vretenar, D.
2017-07-01
Quantum phase transitions between competing equilibrium shapes of nuclei with an odd number of nucleons are explored using a microscopic framework of nuclear energy density functionals and a fermion-boson coupling model. The boson Hamiltonian for the even-even core nucleus, as well as the spherical single-particle energies and occupation probabilities of unpaired nucleons, are completely determined by a constrained self-consistent mean-field calculation for a specific choice of the energy density functional and pairing interaction. Only the strength parameters of the particle-core coupling have to be adjusted to reproduce a few empirical low-energy spectroscopic properties of the corresponding odd-mass system. The model is applied to the odd-A Ba, Xe, La, and Cs isotopes with mass A ≈130 , for which the corresponding even-even Ba and Xe nuclei present a typical case of γ -soft nuclear potential. The theoretical results reproduce the experimental low-energy excitation spectra and electromagnetic properties, and confirm that a phase transition between nearly spherical and γ -soft nuclear shapes occurs also in the odd-A systems.
Casten, R. F.; Cakirli, R. B.
2009-03-01
Understanding the development of configuration mixing, coherence, collectivity, and deformation in nuclei is one of the crucial challenges in nuclear structure physics, and one which has become all the more important with the advent of next generation facilities for the study of exotic nuclei. We will discuss recent work on phase/shape transitional behavior in nuclei, and the role of changes in sub-shell structure in mediating such transitional regions. We will also discuss a newly found, much deeper, link between nuclear structure and nuclear binding energies.
Partonic Structure of Light Nuclei
Armstrong, Whitney; Arrington, John; Cloet, Ian; Hafidi, Kawtar; Hattawy, Mohammad; Potteveld, David; Reimer, Paul; Riordan, Seamus; Yi, Z.; Ball, Jacques; Defurne, Maxime; Garcon, Michel; Moutarde, Herve; Procureur, Sebastien; Sabatie, Franck
2017-01-01
We propose to study the partonic structure of $^4$He by measuring the Beam Spin Asymmetry (BSA) in coherent Deeply Virtual Compton Scattering (DVCS) and the differential cross-section of the Deeply Virtual Meson Production (DVMP) of the $\\phi$. Despite its simple structure, a light nucleus such as $^4$He has a density and a binding energy comparable to that of heavier nuclei. Therefore, by studying $^4$He nucleus, one can learn typical features of the partonic structure of atomic nuclei. The ...
Cavitation inception from bubble nuclei
Mørch, K. A.
2015-01-01
The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid. The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure–time history of the water. A recent model and associated experiments throw new light on the effects of transient pressures on the tensile strength of water, which may be notably reduced or increased by such pressure changes. PMID:26442138
Spontaneous fission of superheavy nuclei
Indian Academy of Sciences (India)
2015-08-02
Aug 2, 2015 ... The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped ...
Direct reactions with exotic nuclei
Directory of Open Access Journals (Sweden)
Obertelli A.
2014-03-01
Full Text Available Direct reactions have been a unique tool to address the nuclear many-body problem from the experimental side. They are now routinely used in inverse kinematics with radioactive ion beams (RIB. However, weakly bound nuclei have recently raised questions on the applicability of reaction formalisms benchmarked on stable nuclei to the study of single-particle properties and correlations in these unstable systems. The study of the most exotic species produced at low intensity have triggered new technical developments to increase the sensitivity of the setup, with a focused attention to direct reactions such as transfer at low incident energy or knockout at intermediate energies.
Shell Structure of Exotic Nuclei
Energy Technology Data Exchange (ETDEWEB)
Dobaczewski, J. [Warsaw University; Michel, N. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Nazarewicz, Witold [ORNL; Ploszajczak, M. [Grand Accelerateur National d' Ions Lourds (GANIL); Rotureau, J. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)
2007-01-01
Theoretical predictions and experimental discoveries for neutron-rich, short-lived nuclei far from stability indicate that the familiar concept of nucleonic shell structure should be considered as less robust than previously thought. The notion of single-particle motion in exotic nuclei is reviewed with a particular focus on three aspects: (i) variations of nuclear mean field with neutron excess due to tensor interactions; (ii) importance of many-body correlations; and (iii) influence of open channels on properties of weakly bound and unbound nuclear states.
Energy Technology Data Exchange (ETDEWEB)
Sida, J.L
2003-07-01
This document gathers a series of 6 lessons dedicated to students in the first year of their thesis (DEA) in fields and particles physics: 1) the extent of nuclear physics, 2) the nucleus as a cluster of interacting fermions, 3) models and deformation, 4) nuclei and rotation, 5) isospin and exotic nuclei, and 6) fission reactions from the saddle point to the scission point.
Fission of hot rotating nuclei: A selfconsistent Thomas-Fermi calculation
Energy Technology Data Exchange (ETDEWEB)
Garcias, F.; Barranco, M.; Nemeth, J.; Ngo, C.; Vinas, X.
1989-05-01
We have studied the symmetric fission of excited nuclei within an axially deformed Thomas-Fermi model that incorporates selfconsistently the effect of rotation and temperature. We have used a realistic Skyrme force and included up to Planck constant/sup 2/ correction terms in the kinetic energy density.
Odd Systems in Deformed Relativistic Hartree Bogoliubov Theory in Continuum
Li, Lu-Lu; Meng, Jie; Ring, P.; Zhao, En-Guang; Zhou, Shan-Gui
2012-04-01
In order to describe the exotic nuclear structure in unstable odd-A or odd-odd nuclei, the deformed relativistic Hartree Bogoliubov theory in continuum is extended to incorporate the blocking effect due to the odd nucleon. For a microscopic and self-consistent description of pairing correlations, continuum, deformation, blocking effects, and the extended spatial density distribution in exotic nuclei, the deformed relativistic Hartree Bogoliubov equations are solved in a Woods—Saxon basis in which the radial wave functions have a proper asymptotic behavior at large r. The formalism and numerical details are provided. The code is checked by comparing the results with those of spherical relativistic continuum Hartree Bogoliubov theory in the nucleus 19O. The prolate deformed nucleus 15C is studied by examining the neutron levels and density distributions.
Electron scattering for exotic nuclei
Indian Academy of Sciences (India)
2014-11-04
Nov 4, 2014 ... A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world's first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density ...
Cavitation Nuclei: Experiments and Theory
DEFF Research Database (Denmark)
Mørch, Knud Aage
2009-01-01
us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories - and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character....
Weak pion production from nuclei
Indian Academy of Sciences (India)
The pion production processes from nucleons and nuclei at intermediate energies are important tools to study the hadronic structure. The dynamic models of the hadronic structure are used to calculate the various nucleon and transition form factors which are tested by using the experimental data on photo, electro and.
Physics with loosely bound nuclei
Indian Academy of Sciences (India)
nuclear physics changed drastically as the new generation of accelerators started providing more and more rare isotopes, which are away from the line of stability. These weakly bound nuclei are found to exhibit new forms of nuclear matter and unprecedented exotic behaviour. The low breakup thresholds of these rare ...
Weak pion production from nuclei
Indian Academy of Sciences (India)
The charged current pion production induced by neutrinos in 12C, 16O and 56Fe nuclei has been studied. The calculations have been done for the coherent as well as the incoherent processes assuming dominance and takes into account the effect of Pauli blocking, Fermi motion and the renormalization of in the ...
Nuclear astrophysics of light nuclei
DEFF Research Database (Denmark)
Fynbo, Hans Otto Uldall
2013-01-01
A review of nuclear astrophysics of light nuclei using radioactive beams or techniques developed for radioactive beams is given. We discuss Big Bang nucleosynthesis, with special focus on the lithium problem, aspects of neutrino-physics, helium-burning and finally selected examples of studies...
Nomura, K.; Rodríguez-Guzmán, R.; Robledo, L. M.
2017-07-01
Spectroscopic properties of odd-mass nuclei are studied within the framework of the interacting boson-fermion model (IBFM) with parameters based on the Hartree-Fock-Bogoliubov (HFB) approximation. The parametrization D1M of the Gogny energy density functional (EDF) was used at the mean-field level to obtain the deformation energy surfaces for the considered nuclei in terms of the quadrupole deformations (β ,γ ). In addition to the energy surfaces, both single-particle energies and occupation probabilities were used as a microscopic input for building the IBFM Hamiltonian. Only three strength parameters for the particle-boson-core coupling are fitted to experimental spectra. The IBFM Hamiltonian is then used to compute the energy spectra and electromagnetic transition rates for selected odd-mass Eu and Sm nuclei as well as for 195Pt and 195Au. A reasonable agreement with the available experimental data is obtained for the considered odd-mass nuclei.
Energy Technology Data Exchange (ETDEWEB)
Pittel, S. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, 19716 Delaware (United States); Dussel, G. G. [Departamento de Fisica J.J. Giambiagi, Universidad de Buenos Aires, 1428 Buenos Aires (Argentina); Dukelsky, J.; Sarriguren, P. [Instituto de Estructura de la Materia, CSIC, Serrano 123, 28006 Madrid (Spain)
2008-12-15
We describe recent efforts to study Cooper pairs in atomic nuclei. We consider a self-consistent Hartree Fock mean field for the even Sm isotopes and compare results based on three treatments of pairing correlations: a BCS treatment, a number-projected BCS treatment and an exact treatment using the Richardson Ansatz. Significant differences are seen in the pairing correlation energies. Furthermore, because it does not average over the properties of the fermion pairs, the Richardson solution permits a more meaningful definition of the Cooper wave function and of the fraction of pairs that are collective. Our results confirm that only a few pairs near the Fermi surface in realistic atomic nuclei are collective. (Author)
Deformation effects in the Si + C and Si + Si reactions
Indian Academy of Sciences (India)
to the energy of the conjectured В = 38 quasi-molecular resonance [4]. The study of light charged particle (LCP) emission is a good tool in exploring nuclear deformations and other properties of hot rotating nuclei at high spins and angular mo- menta [12–16]. The present work has been performed with the aim to investigate ...
Bohr Hamiltonian with deformation-dependent mass term
Energy Technology Data Exchange (ETDEWEB)
Bonatsos, Dennis, E-mail: bonat@inp.demokritos.g [Institute of Nuclear Physics, N.C.S.R. ' Demokritos' , GR-15310 Aghia Paraskevi, Attiki (Greece); Georgoudis, P.; Lenis, D. [Institute of Nuclear Physics, N.C.S.R. ' Demokritos' , GR-15310 Aghia Paraskevi, Attiki (Greece); Minkov, N. [Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 Tzarigrad Road, 1784 Sofia (Bulgaria); Quesne, C. [Physique Nucleaire Theorique et Physique Mathematique, Universite Libre de Bruxelles, Campus de la Plaine CP229, Boulevard du Triomphe, B-1050 Brussels (Belgium)
2010-01-25
The Bohr Hamiltonian describing the collective motion of atomic nuclei is modified by allowing the mass to depend on the nuclear deformation. Exact analytical expressions are derived for spectra and wave functions in the case of a gamma-unstable Davidson potential, using techniques of supersymmetric quantum mechanics. Numerical results in the Xe-Ba region are discussed.
Superheavy nuclei and fission barriers
Lu, Bing-Nan; Zhao, Jie; Zhao, En-Guang; Zhou, Shan-Gui
In this chapter, we will present relativistic mean field (RMF) description of heavy and superheavy nuclei (SHN). We will discuss the shell structure and magic numbers in the mass region of SHN, binding energies and α decay Q values, shapes of ground states and potential energy surfaces and fission barriers. We particularly focus on the multidimensionally-constrained covariant density functional theories (CDFT) and the applications of CDFT to the study of exotic nuclear shapes and fission barriers.
A novel deformation mechanism for superplastic deformation
Energy Technology Data Exchange (ETDEWEB)
Muto, H.; Sakai, M. (Toyohashi Univ. of Technology (Japan). Dept. of Materials Science)
1999-01-01
Uniaxial compressive creep tests with strain value up to -0.1 for a [beta]-spodumene glass ceramic are conducted at 1060 C. From the observation of microstructural changes between before and after the creep deformations, it is shown that the grain-boundary sliding takes place via cooperative movement of groups of grains rather than individual grains under the large-scale-deformation. The deformation process and the surface technique used in this work are not only applicable to explain the deformation and flow of two-phase ceramics but also the superplastic deformation. (orig.) 12 refs.
Systematic study on the competition between α-decay and spontaneous fission of superheavy nuclei
Zhang, Y. L.; Wang, Y. Z.
2017-10-01
The competition between α-decay and spontaneous fission (SF) of Z = 112 isotopes are studied. The α-decay half-lives are estimated by the generalized liquid-drop model (GLDM) and several sets of analytic formulas. These formulas include the Royer formula, Viola-Seaborg semiempirical (VSS) formula and universal decay law (UDL). For the SF, its half-lives are calculated by using the Xu, Ren, Karpov and Santhosh formulas. It is shown that the predicted α-decay half-lives by different approaches are more or less identical. However, the SF half-lives are highly sensitive to models. To test the accuracies of different SF formulas, the half-lives of 56 even-even heavy nuclei are calculated by these formulas. By comparing with the experimental data, it is found that the Xu formula is the most accurate one to reproduce the experimental SF half-lives. This allows us to make a systematic prediction on the competition between α-decay and SF of even-even superheavy nuclei (SHN) with Z = 104- 120 by using the Xu formula and the above mentioned models on α-decay. The calculations suggest that 258,260104, 268-276110, 270-280112, 272-286114, 274-294116, 284-302118 and 292-308120 have smaller α-decay half-lives than those of SF. Thus these nuclei can be synthesized and identified via α-decay in the laboratory. In addition, it is observed that N = 162, 178, 184 and 196 may be the submagic or magic numbers. Finally, an extensive study on the possible α-decay chains for Z = 120 isotopes is performed. It is predicted that six sequential α-decay chains can be observed from 292-296120, four α-decay chains from 298120, three α-decay chains from 300,302120, two α-decay chains from 304,306120, and only one α-decay chain from 308120. These nuclei are the most likely candidates to be synthesized experimentally via α-decay in the near future.
Spontaneous fission of superheavy nuclei
Indian Academy of Sciences (India)
and penetrability for binary nuclear configurations typical for fission processes. The deformed two- ... Finally, the WKB method is used to calculate penetrabilities and spontaneous fission half-lives. Calculations ... the mass tensor components contain binary character of the process, because the pairing. Pramana – J. Phys.
Proton scattering from unstable nuclei
Indian Academy of Sciences (India)
states gives access to transition probabilities and nuclear deformations, and is a well suited tool to scan new regions of ... measured through Coulomb and hadronic excitation should give access to the isoscalar or isovector nature of the .... In the present work, we employed self-consistent microscopic models with Skyrme ef-.
Hyperheavy nuclei in covariant density functional theory: the existence and stability
Gyawali, Abhinaya; Agbemava, Sylvester; Afanasjev, Anatoli
2017-09-01
The limits of existence of finite nuclei is one of interesting questions of modern low-energy nuclear physics. A lot of theoretical efforts have been dedicated to the study of superheavy nuclei with Z 126 . Almost all investigations of such nuclei consider only spherical shapes for the ground states. However, the study of superheavy nuclei indicates that such assumption leads in many cases to misinterpretation of the situation. Thus, we performed a systematic investigation of such nuclei for proton numbers from 122 up to 184 and from two-proton drip line up to two-neutron one within the axial relativistic Hartree-Bogoliubov theory. The calculations are carried out in large deformation space extending from megadeformed oblate shapes via spherical ones up to scission configuration. The stability of such nuclei against fission (including triaxial and octupole shapes) and beta-decays have been investigated and the islands of their stability have been defined. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award No. DE-SC0013037 and by Department of Energy, National Nuclear Security Administration under Award Number DE-NA0002925.
ISOLATION OF SKELETAL MUSCLE NUCLEI
Edelman, Jean C.; Edelman, P. Michael; Knigge, Karl M.; Schwartz, Irving L.
1965-01-01
A method employing aqueous media for isolation of nuclei from rat skeletal muscle is described. The technique involves (a) mincing and then homogenizing in a 0.32 M sucrose-salt solution with a Potter-Elvehjem type homogenizer using a Delrin (an acetal resin) pestle and a carefully controlled, relatively large pestle-to-glass clearance, (b) filtering through fiberglass and stainless steel screens of predetermined mesh size to remove myofibrils and connective tissue, and (c) centrifuging in a 2.15 M sucrose-salt solution containing 0.7 mM ATP. Electron and phase-contrast microscopic observations show that the nuclei are intact, unencumbered by cytoplasmic tags, and possess well preserved distinct nucleoli, nucleoplasm, and nuclear membranes. Cytoplasmic contamination is minimal and mainly mitochondrial. Chemical assays of the nuclear fraction show that the DNA/protein and RNA/DNA ratios are comparable to those obtained in other tissues. These ratios, as well as the low specific activity obtained for cytochrome c oxidase and the virtual absence of myofibrillar ATPase, indicate a high degree of purity with minimal mitochondrial and myofibrillar contamination. The steps comprising the technique and the reasons for their selection are discussed. PMID:4287141
Fusion-fission probabilities, cross sections, and structure notes of superheavy nuclei
Kowal, Michał; Cap, Tomasz; Jachimowicz, Piotr; Skalski, Janusz; Siwek-Wilczyńska, Krystyna; Wilczyński, Janusz
2016-12-01
Fusion - fission probabilities in the synthesis of heaviest elements are discussed in the context of the latest experimental reports. Cross sections for superheavy nuclei are evaluated using the "Fusion by Diffusion" (FBD) model. Predictive power of this approach is shown for experimentally known Lv and Og isotopes and predictions given for Z = 119, 120. Ground state and saddle point properties as masses, shell corrections, pairing energies, and deformations necessary for cross-section estimations are calculated systematically within the multidimensional microscopic-macroscopic method based on the deformed Woods-Saxon single-particle potential. In the frame of the FBD approach predictions for production of elements heavier than Z = 118 are not too optimistic. For this reason, and because of high instability of superheavy nuclei, we comment on some structure effects, connected with the K-isomerism phenomenon which could lead to a significant increase in the stability of these systems.
Fusion-fission probabilities, cross sections, and structure notes of superheavy nuclei
Directory of Open Access Journals (Sweden)
Kowal Michał
2016-01-01
Full Text Available Fusion – fission probabilities in the synthesis of heaviest elements are discussed in the context of the latest experimental reports. Cross sections for superheavy nuclei are evaluated using the “Fusion by Diffusion” (FBD model. Predictive power of this approach is shown for experimentally known Lv and Og isotopes and predictions given for Z = 119, 120. Ground state and saddle point properties as masses, shell corrections, pairing energies, and deformations necessary for cross-section estimations are calculated systematically within the multidimensional microscopic-macroscopic method based on the deformed Woods-Saxon single-particle potential. In the frame of the FBD approach predictions for production of elements heavier than Z = 118 are not too optimistic. For this reason, and because of high instability of superheavy nuclei, we comment on some structure effects, connected with the K-isomerism phenomenon which could lead to a significant increase in the stability of these systems.
Studies of the shapes of heavy pear-shaped nuclei at ISOLDE
Energy Technology Data Exchange (ETDEWEB)
Butler, P. A., E-mail: peter.butler@liverpool.ac.uk [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom)
2016-07-07
For certain combinations of protons and neutrons there is a theoretical expectation that the shape of nuclei can assume octupole deformation, which would give rise to reflection asymmetry or a ”pear-shape” in the intrinsic frame, either dynamically (octupole vibrations) or statically (permanent octupole deformation). I will briefly review the historic evidence for reflection asymmetry in nuclei and describe how recent experiments carried out at REX-ISOLDE have constrained nuclear theory and how they contribute to tests of extensions of the Standard Model. I will also discuss future prospects for measuring nuclear shapes from Coulomb Excitation: experiments are being planned that will exploit beams from HIE-ISOLDE that are cooled in the TSR storage ring and injected into a solenoidal spectrometer similar to the HELIOS device developed at the Argonne National Laboratory.
Mitropolsky, I.
2005-05-01
On the grounds of a file of the evaluated nuclear data ENSDF, the most complete compilation of rotational bands in odd-A nuclei with mass numbers 43⩽A⩽253 is presented. The processing of experimental data has been carried out on the basis of generalization of the variable moment of inertia model for axial strong deformed nuclei, which is taking into account the decoupling effect for bands with K=1/2. The good description of rotational energies for the majority of rotational bands is obtained and the systematic behavior of the model parameters in all areas of the deformed nuclei is shown. The theoretical description was used for association of fragments of rotational bands, exclusion of "superfluous" levels and prediction of a placement of "missed" levels.
Quartet correlations in N = Z nuclei induced by realistic two-body interactions
Energy Technology Data Exchange (ETDEWEB)
Sambataro, M. [Istituto Nazionale di Fisica Nucleare - Sezione di Catania, Catania (Italy); Sandulescu, N. [National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania)
2017-03-15
Two variational quartet models previously employed in a treatment of pairing forces are extended to the case of a general two-body interaction. One model approximates the nuclear states as a condensate of identical quartets with angular momentum J = 0 and isospin T = 0 while the other let these quartets to be all different from each other. With these models we investigate the role of alpha-like quartet correlations both in the ground state and in the lowest J = 0, T = 0 excited states of even-even N = Z nuclei in the sd -shell. We show that the ground-state correlations of these nuclei can be described to a good extent in terms of a condensate of alpha-like quartets. This turns out to be especially the case for the nucleus {sup 32}S for which the overlap between this condensate and the shell model wave function is found close to one. In the same nucleus, a similar overlap is found also in the case of the first excited 0{sup +} state. No clear correspondence is observed instead between the second excited states of the quartet models and the shell model eigenstates in all the cases examined. (orig.)
Structures of Superdeforemed States in Nuclei with A~60 Using Two-Parameter Collective Model
Directory of Open Access Journals (Sweden)
Gaballah N.
2015-01-01
Full Text Available Superdeformed (SD states in nuclei in mass region A ∼ 60 − 90 are investigated within the framework of two-parameter formula of Bohr and Motelson model. The concept of γ -ray transition energy E γ over spin (EGOS is used to assign the first order estimation of the bandhead spin. The model parameters and the true spin o f bandhead have been obtained by adopted best fit method in order to obtain a minimum root-mean-square deviation between the calculated and the experimental γ -ray transition energies. The transition energies E γ and the dynamical moment of inertia J (2 for data set include thir- teen SD bands in even-even nuclei are calculated. The result s agree with experimental data well. The behavior of J (2 as a function of rotational frequency ~ ω are discussed. By using the calculated bandhead moment of inertia, the predicted quadrupole moments of the studied yrast SD bands are calculated and agree well with the observed data.
Low-Lying Collective Levels in 224-234 Th Nuclei
Diab S. M.
2008-01-01
The low-lying collective levels in 224 - 234 Th isotopes are investigated in the frame work of the interacting boson approximation model (IBA-1). The contour plot of the poten- tial energy surfaces, V ( ; ) , shows two wells on the prolate and oblate sides which indicate that all thorium nuclei are deformed and have rotational characters. The levels energy, electromagnetic transition rates B(E1) and B(E2) are calculated. Bending at angular momentu...
Anharmonic double-{gamma} vibrations in nuclei and their description in the interacting boson model
Energy Technology Data Exchange (ETDEWEB)
Garcia-Ramos, J.E.; Alonso, C.E.; Arias, J.M. [Sevilla Univ. (Spain). Departamento de Fisica Atomica, Molecular y Nuclear; Van Isacker, P. [Grand Accelerateur National d`Ions Lourds, 14 - Caen (France)
1998-07-01
Double-{gamma} vibrations in deformed nuclei are studied in the context of the interacting boson model with special reference to their anharmonic character. It is shown that large anharmonicities can be obtained with interactions that are (at least) of three-body nature between the bosons. As an example the {gamma} vibrations of the nucleus {sub 68}{sup 166}Er{sub 98} are studied in detail. (author) 28 refs.
Universal deformation formulas
Remm, E.; Markl, M.
2015-01-01
We give a conceptual explanation of universal deformation formulas for unital associative algebras and prove some results on the structure of their moduli spaces. We then generalize universal deformation formulas to other types of algebras and their diagrams.
Deformation properties of lead isotopes
Energy Technology Data Exchange (ETDEWEB)
Tolokonnikov, S. V.; Borzov, I. N.; Lutostansky, Yu. S.; Saperstein, E. E., E-mail: saper43-7@mail.ru [National Research Center Kurchatov Institute (Russian Federation)
2016-01-15
The deformation properties of a long lead isotopic chain up to the neutron drip line are analyzed on the basis of the energy density functional (EDF) in the FaNDF{sup 0} Fayans form. The question of whether the ground state of neutron-deficient lead isotopes can have a stable deformation is studied in detail. The prediction of this deformation is contained in the results obtained on the basis of the HFB-17 and HFB-27 Skyrme EDF versions and reported on Internet. The present analysis reveals that this is at odds with experimental data on charge radii and magnetic moments of odd lead isotopes. The Fayans EDF version predicts a spherical ground state for all light lead isotopes, but some of them (for example, {sup 180}Pb and {sup 184}Pb) prove to be very soft—that is, close to the point of a phase transition to a deformed state. Also, the results obtained in our present study are compared with the predictions of some other Skyrme EDF versions, including SKM*, SLy4, SLy6, and UNE1. By and large, their predictions are closer to the results arising upon the application of the Fayans functional. For example, the SLy4 functional predicts, in just the same way as the FaNDF{sup 0} functional, a spherical shape for all nuclei of this region. The remaining three Skyrme EDF versions lead to a deformation of some light lead isotopes, but their number is substantially smaller than that in the case of the HFB-17 and HFB-27 functionals. Moreover, the respective deformation energy is substantially lower, which gives grounds to hope for the restoration of a spherical shape upon going beyond the mean-field approximation, which we use here. Also, the deformation properties of neutron-rich lead isotopes are studied up to the neutron drip line. Here, the results obtained with the FaNDF{sup 0} functional are compared with the predictions of the HFB-17, HFB-27, SKM*, and SLy4 Skyrme EDF versions. All of the EDF versions considered here predict the existence of a region where neutron
Mean-field models and exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Bender, M.; Buervenich, T.; Maruhn, J.A.; Greiner, W. [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); Rutz, K. [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany)]|[Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Reinhard, P.G. [Inst. fuer Theoretische Physik, Univ. Erlangen (Germany)
1998-06-01
We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)
RFP for the Comet Nuclei Tour (CONTOUR)
DEFF Research Database (Denmark)
Jørgensen, John Leif; Madsen, Peter Buch; Betto, Maurizio
1999-01-01
This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program.......This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program....
Decay of heavy and superheavy nuclei
Indian Academy of Sciences (India)
Hence, considerable attention has been given by the experimentalists to the investigation of the existence of superheavy nuclei (SHN) beyond the valley of ... But the advances in technology have made it experi- mentally possible to identify the nuclei in exited states having relatively large life span. Pramana – J. Phys., Vol.
DTM: Deformable Template Matching
Lee, Hyungtae; Kwon, Heesung; Robinson, Ryan M.; Nothwang, William D.
2016-01-01
A novel template matching algorithm that can incorporate the concept of deformable parts, is presented in this paper. Unlike the deformable part model (DPM) employed in object recognition, the proposed template-matching approach called Deformable Template Matching (DTM) does not require a training step. Instead, deformation is achieved by a set of predefined basic rules (e.g. the left sub-patch cannot pass across the right patch). Experimental evaluation of this new method using the PASCAL VO...
Ground-state properties of neutron magic nuclei
Energy Technology Data Exchange (ETDEWEB)
Saxena, G., E-mail: gauravphy@gmail.com [Govt. Women Engineering College, Department of Physics (India); Kaushik, M. [Shankara Institute of Technology, Department of Physics (India)
2017-03-15
A systematic study of the ground-state properties of the entire chains of even–even neutron magic nuclei represented by isotones of traditional neutron magic numbers N = 8, 20, 40, 50, 82, and 126 has been carried out using relativistic mean-field plus Bardeen–Cooper–Schrieffer approach. Our present investigation includes deformation, binding energy, two-proton separation energy, single-particle energy, rms radii along with proton and neutron density profiles, etc. Several of these results are compared with the results calculated using nonrelativistic approach (Skyrme–Hartree–Fock method) along with available experimental data and indeed they are found with excellent agreement. In addition, the possible locations of the proton and neutron drip-lines, the (Z, N) values for the new shell closures, disappearance of traditional shell closures as suggested by the detailed analyzes of results are also discussed in detail.
Felgitsch, Laura; Seifried, Teresa; Winkler, Philipp; Schmale, David, III; Grothe, Hinrich
2017-04-01
While the importance of heterogeneous ice nucleation in the atmosphere is known, we still know very little about the substances triggering these freezing events. Recent findings support the theory that biological ice nuclei (IN) exhibit the ability to play an important role in these processes. Huffman et al. (2013) showed a burst of biological IN over woodlands triggered by rain events. Birch pollen are known to release a high number of efficient IN if incubated in water (Pummer et al. 2012). Therefore birches are of interest in our research on this topic. Plants native to the timberline, such as birch trees, have to cope with very cold climatic conditions, rendering freezing avoidance impossible. These plants trigger freezing in their extracellular spaces to control the freezing process and avoid intracellular freezing, which would have lethal consequences. The plants hereby try to freeze at a temperature well above homogeneous freezing temperatures but still at temperatures low enough to not be effected by brief night frosts. To achieve this, IN are an important tool. The specific objective of our work was to study the potential sources and distribution of IN in birch trees. We collected leaves, fruit, bark, and trunk cores from a series of mature birch trees in Tyrol, Austria at different altitudes and sampling sites. We also collected samples from a birch tree in an urban park in Vienna, Austria. Our data show a sampling site dependence and the distribution of IN throughout the tree. Our data suggest that leaves, bark, and wood of birch can function as a source of IN, which are easily extracted with water. The IN are therefore not restricted to pollen. Hence, the amount of IN, which can be released from birch trees, is tremendous and has been underrated so far. Future work aims to elucidate the nature, contribution, and potential ecological roles of IN from birch trees in different habitats. Huffman, J.A., Prenni, A.J., DeMott, P.J., Pöhlker, C., Mason, R
Molecular outflows in starburst nuclei
Roy, Arpita; Nath, Biman B.; Sharma, Prateek; Shchekinov, Yuri
2016-12-01
Recent observations have detected molecular outflows in a few nearby starburst nuclei. We discuss the physical processes at work in such an environment in order to outline a scenario that can explain the observed parameters of the phenomenon, such as the molecular mass, speed and size of the outflows. We show that outflows triggered by OB associations, with NOB ≥ 105 (corresponding to a star formation rate (SFR)≥1 M⊙ yr-1 in the nuclear region), in a stratified disc with mid-plane density n0 ˜ 200-1000 cm-3 and scaleheight z0 ≥ 200(n0/102 cm-3)-3/5 pc, can form molecules in a cool dense and expanding shell. The associated molecular mass is ≥107 M⊙ at a distance of a few hundred pc, with a speed of several tens of km s-1. We show that an SFR surface density of 10 ≤ ΣSFR ≤ 50 M⊙ yr-1 kpc-2 favours the production of molecular outflows, consistent with observed values.
The morphology of cometary nuclei
Keller, H. U.; Jorda, L.
comets display residual activity or clouds of dust grains around their nuclei. Taking the residual signal into account (mostly using simple models for the brightness distribution) the size estimates of the nuclei could be improved. The (nuclear) magnitude of a comet depends on the product of its albedo and cross-section. Only in a few cases could the albedo and size of a cometary nucleus be separated by additional observation of its thermal emission at infrared wavelengths. By comparison with outer Solar System asteroids Cruikshank et al. (1985) derived a surprisingly low albedo of about 0.04. A value in clear contradiction to the perception of an icy surface but fully confirmed by the first resolved images of a cometary nucleus during the flybys of the Vega and Giotto spacecraft of comet Halley (Sagdeev et al. 1986, Keller et al. 1986). The improvements of radar techniques led to the detection of reflected signals and finally to the derivation of nuclear dimensions and rotation rates. The observations, however, are also model dependent (rotation and size are similarly interwoven as are albedo and size) and sensitive to large dust grains in the vicinity of a nucleus. As an example, Kamoun et al. (1982) determined the radius of comet Encke to 1.5 (2.3, 1.0) km using the spin axis determination of Whipple and Sekanina (1979). The superb spatial resolution of the Hubble Space Telescope (HST) is not quite sufficient to resolve a cometary nucleus. The intensity distribution of the inner coma, however, can be observed and extrapolated toward the nucleus based on models of the dust distribution. If this contribution is subtracted from the central brightness the signal of the nucleus can be derived and hence its product of albedo times cross-section (Lamy and Toth 1995, Rembor 1998, Keller and Rembor 1998; Section 4.3). It has become clear that cometary nuclei are dark, small, often irregular bodies with dimensions ranging from about a kilometre (comet Wirtanen, the target of
Systematic study of properties of Hs nuclei
Energy Technology Data Exchange (ETDEWEB)
Ma, L.; Zhou, X.H.; Gan, Z.G. [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Zhang, H.F. [Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China); Li, J.Q. [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China); Scheid, W. [Physik der Universitaet, Institut fuer Theoretische, Giessen (Germany)
2010-12-15
The ground-state properties of Hs nuclei are studied in the framework of the relativistic mean-field theory. We find that the more relatively stable isotopes are located on the proton abundant side of the isotopic chain. The last stable nucleus near the proton drip line is probably the {sup 255}Hs nucleus. The {alpha} -decay half-lives of Hs nuclei are predicted, and together with the evaluation of the spontaneous-fission half-lives it is shown that the nuclei, which are possibly stable against spontaneous fission are {sup 263-274}Hs. This is in coincidence with the larger binding energies per nucleon. If {sup 271-274}Hs can be synthesized and identified, only those nuclei from the upper Z=118 isotopic chain, which are lighter than the nucleus {sup 294}118, and those nuclei in the corresponding {alpha} -decay chain lead to Hs nuclei. The most stable unknown Hs nucleus is {sup 268}Hs. The density-dependent delta interaction pairing is used to improve the BCS pairing correction, which results in more reasonable single-particle energy level distributions and nucleon occupation probabilities. It is shown that the properties of nuclei in the superheavy region can be described with this interaction. (orig.)
MRI atlas of the human cerebellar nuclei.
Dimitrova, A; Weber, J; Redies, C; Kindsvater, K; Maschke, M; Kolb, F P; Forsting, M; Diener, H C; Timmann, D
2002-09-01
The differential role of the cerebellar cortex and nuclei has rarely been addressed in human lesion and functional brain imaging studies. One important reason is the difficulty of defining the localization of the cerebellar nuclei and extent of possible lesions based on CT or MR scans. The present MRI investigation was specifically designed to study the anatomy of the deep cerebellar nuclei. In both basal ganglia and cerebellar nuclei of healthy human subjects the amount of iron is high compared to the rest of the brain. Clusters of iron are paramagnetic and, therefore, tend to cause local inhomogenities in a magnetic field. The iron-induced susceptibility artefacts were used to visualize the cerebellar nuclei as hypointensities on MR images. A three-dimensional atlas of the dentate (D), interposed (I), and fastigial (F) nuclei is presented in standard proportional stereotaxic space coordinates based on findings in a healthy 26-year-old female. A three-dimensional axial volume of the cerebellum was acquired using a T1-weighted fast low-angle shot (FLASH) sequence on a Siemens Sonata 1.5 Tesla MR. To increase the signal to noise ratio the sequence was acquired 5 times and averaged. Each volume was registered, resampled to 1.00 x 1.00 x 1.00-mm3 voxel size and spatially normalized into a standard proportional stereotaxic space (the MNI-space) using SPM99. Localization of cerebellar nuclei were confirmed by comparison with postmortem MRI and histological microsections of another brain.
Nucleation of recrystallization at selected sites in deformed fcc metals
DEFF Research Database (Denmark)
Xu, Chaoling
The objective of this thesis is to explore nucleation of recrystallization at selected sites in selected face-centered-cubic (FCC) metals, namely cold rolled columnar-grained nickel and high purity aluminum further deformed by indenting. Various techniques, including, optical microscopy, electron...... are observed with orientations different from the surrounding matrix. Hardness measurements at TJs in the deformed sample indicate a weak correlation between the difference in hardness among the three grains at the TJs and the potentials of the junctions to form nuclei: the higher the difference, the more...
Simulation of sub-barrier fusion process including dynamical deformation
Energy Technology Data Exchange (ETDEWEB)
Hata, Kentaro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1997-05-01
Four reactions ({sup 40}Ca+{sup 40}Ca, {sup 58}Ni+{sup 58}Ni, {sup 64}Ni+{sup 64}Ni and {sup 74}Ge+{sup 74}Ge) were simulated as examples of spherical nuclei, {sup 40}Ca and {sup 58}Ni and dynamical deformation, {sup 64}Ni and {sup 74}Ge. The experimental excited functions of sub-barrier fusion reaction were reproduced with high accuracy without free parameters. The sub-barrier fusion process had supposed to pass one-dimensional fusion process estimated by the principle of least action on the potential surface with a freedom of nuclear deformation. (S.Y.)
Proton bombarded reactions of Calcium target nuclei
Directory of Open Access Journals (Sweden)
Tel Eyyup
2017-01-01
Full Text Available In this study, proton bombarded nuclear reactions calculations of Calcium target nuclei have been investigated in the incident proton energy range of 1–50 MeV. The excitation functions for 40Ca target nuclei reactions have been calculated by using PCROSS nuclear reaction calculation code. Weisskopf-Ewing and the full exciton models were used for equilibrium and for pre-equilibrium calculations, respectively. The excitation functions for 40Ca target nuclei reactions (p,α, (p,n, (p,p have been calculated using the semi-empirical formula Tel et al. [5].
Superheavy nuclei – cold synthesis and structure
Indian Academy of Sciences (India)
isotopes of Pb, Kr, Ca (or neighbouring nuclei) and the light nuclei, like C, N, O and Ne, as. 481 ... ¾ ¾102 isotope in its reaction with different Pb target nuclei. The ..... 0.455. Zn. ѕјPb. 0.356. Sr. ѕјPb. 0.427. ¾Ge. ѕјHg. 0.093. ЅїXe. ½ Dy. 0.062. ЅїTe. ½ ¾Nd. 490. Pramana – J. Phys., Vol. 57, Nos 2 & 3, Aug. & Sept. 2001 ...
NUCLEI SHAPE ANALYSIS, A STATISTICAL APPROACH
Directory of Open Access Journals (Sweden)
Alberto Nettel-Aguirre
2011-05-01
Full Text Available The method presented in our paper suggests the use of Functional Data Analysis (FDA techniques in an attempt to characterise the nuclei of two types of cells: Cancer and non-cancer, based on their 2 dimensional profiles. The characteristics of the profile itself, as traced by its X and Y coordinates, their first and second derivatives, their variability and use in characterization are the main focus of this approach which is not constrained to star shaped nuclei. Findings: Principal components created from the coordinates relate to shape with significant differences between nuclei type. Characterisations for each type of profile were found.
Fission and Properties of Neutron-Rich Nuclei
Hamilton, Joseph H.; Ramayya, A. V.; Carter, H. K.
2008-08-01
Opening session. Nuclear processes in stellar explosions / M. Wiescher. In-beam [symbol]-ray spectroscopy of neutron-rich nuclei at NSCL / A. Gade -- Nuclear structure I. Shell-model structure of neutron-rich nuclei beyond [symbol]Sn / A. Covello ... [et al.]. Shell structure and evolution of collectivity in nuclei above the [symbol]Sn core / S. Sarkar and M. S. Sarkar. Heavy-ion fusion using density-constrained TDHF / A. S. Umar and V. E. Oberacker. Towards an extended microscopic theory for upper-fp shell nuclei / K. P. Drumev. Properties of the Zr and Pb isotopes near the drip-line / V. N. Tarasov ... [et al.]. Identification of high spin states in [symbol] Cs nuclei and shell model calculations / K. Li ... [et al.]. Recent measurements of spherical and deformed isomers using the Lohengrin fission-fragment spectrometer / G. S. Simpson ... [et al.] -- Nuclear structure II. Nuclear structure investigation with rare isotope spectroscopic investigations at GSI / P. Boutachkov. Exploring the evolution of the shell structures by means of deep inelastic reactions / G. de Anaelis. Probing shell closures in neutron-rich nuclei / R. Krücken for the S277 and REX-ISOLDEMINIBALL collaborations. Structure of Fe isotopes at the limits of the pf-shell / N. Hoteling ... [et al.]. Spectroscopy of K isomers in shell-stabilized trans-fermium nuclei / S. K. Tandel ... [et al.] -- Radioactive ion beam facilities. SPIRAL2 at GANIL: a world leading ISOL facility for the next decade / S. Gales. New physics at the International Facility for Antiproton and Ion Research (FAIR) next to GSI / I. Augustin ... [et al.]. Radioactive beams from a high powered ISOL system / A. C. Shotter. RlKEN RT beam factory / T. Motobayashi. NSCL - ongoing activities and future perspectives / C. K. Gelbke. Rare isotope beams at Argonne / W. F. Henning. HRIBF: scientific highlights and future prospects / J. R. Beene. Radioactive ion beam research done in Dubna / G. M. Ter-Akopian ... [et al.] -- Fission I
Energy Technology Data Exchange (ETDEWEB)
Khalfallah, F
2007-08-15
Within the recent years, the spectroscopic study of single particle orbitals of very heavy elements (VHE) has become possible with the development of increasingly efficient experimental setups. This allows us, through nuclear deformation, to access with these deformed nuclei to orbitals situated around the Fermi level in the spherical superheavy elements (SHE) and learn more about the nuclear structure of these nuclei. The aim of this work is the spectroscopic studies of heavy and very heavy elements. Because of the experimental difficulties associated with the fusion reactions in the VHE region, a detailed optimization studies is essential. Simulation of energy loss and angular straggling of these nuclei due to the interaction in the target and to neutron's evaporation was carried out and allowed us to optimize the angular acceptance of the separators according to the target thickness. An extensive survey and exploration in the VHE region was also conducted on the basis of cross section's systematics in the literature and simulations carried out using the statistical code Hivap. In this framework, the possible extension of the range of validity of a set of Hivap parameters was investigated. This work has enabled us to prepare a list of experiments of interest for the production of very heavy nuclei. In this thesis, our work was concentrated on the spectroscopy of the nuclei No{sup 256} et Rf{sup 256} for which two experimental proposals were accepted. The octupole deformations predicted in the actinides region is studied in another part of this thesis, a part witch is dedicated to the gamma spectroscopy of Pa{sup 223}. The data from a new experiment carried out using the Jurogam-Ritu-Great setup are analysed and compared to previous results. They confirm the octupole deformed shape in this nucleus. (author)
Electron scattering sum rules in polarized nuclei
Energy Technology Data Exchange (ETDEWEB)
Lipparini, E.; Stringari, S.
1989-07-01
Sum rules for the inelastic scattering of polarized electrons frompolarized nuclei are derived and discussed. The role of the nucleon formfactors is investigated with special emphasis to the case of deuteron and/sup 3/He.
Parton distributions in nuclei: Quagma or quagmire
Energy Technology Data Exchange (ETDEWEB)
Close, F.E.
1988-01-01
The emerging information on the way quark, antiquark, and gluon distributions are modified in nuclei relative to free nucleons is reviewed. Particular emphasis is placed on Drell-Yan and /psi/ production on nuclei and caution against premature use of these as signals for quagma in heavy-ion collisions. If we are to identify the formation of quark-gluon plasma in heavy-ion collisions by changes in the production rates for /psi/ relative to Drell-Yan lepton pairs, then it is important that we first understand the ''intrinsic'' changes in parton distributions in nuclei relative to free nucleons. So, emerging knowledge on how quark, antiquark, and gluon distributions are modified in nuclei relative to free nucleons is reviewed, and the emerging theoretical concensus is briefly summarized.
From Nucleons To Nuclei To Fusion Reactions
Energy Technology Data Exchange (ETDEWEB)
Quaglioni, S; Navratil, P; Roth, R; Horiuchi, W
2012-02-15
Nuclei are prototypes of many-body open quantum systems. Complex aggregates of protons and neutrons that interact through forces arising from quantum chromo-dynamics, nuclei exhibit both bound and unbound states, which can be strongly coupled. In this respect, one of the major challenges for computational nuclear physics, is to provide a unified description of structural and reaction properties of nuclei that is based on the fundamental underlying physics: the constituent nucleons and the realistic interactions among them. This requires a combination of innovative theoretical approaches and high-performance computing. In this contribution, we present one of such promising techniques, the ab initio no-core shell model/resonating-group method, and discuss applications to light nuclei scattering and fusion reactions that power stars and Earth-base fusion facilities.
Relativistic symmetry breaking in light kaonic nuclei
Energy Technology Data Exchange (ETDEWEB)
Yang, Rong-Yao; Jiang, Wei-Zhou; Zhang, Dong-Rui; Wei, Si-Na [Southeast University, Department of Physics, Nanjing (China); Xiang, Qian-Fei [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China)
2014-12-01
As the experimental data from kaonic atoms and K{sup -}N scatterings imply that the K{sup -} -nucleon intenraction is strongly attractive at saturation density, there is a possibility to form K{sup -} -nuclear bound states or kaonic nuclei. In this work, we investigate the ground-state properties of the light kaonic nuclei with the relativistic mean-field theory. It is found that the strong attraction between K{sup -} and nucleons reshapes the scalar and vector meson fields, leading to the remarkable enhancement of the nuclear density in the interior of light kaonic nuclei and the manifest shift of the single-nucleon energy spectra and magic numbers therein. As a consequence, the pseudospin symmetry is shown to be violated together with enlarged spin-orbit splittings in these kaonic nuclei. (orig.)
Cluster dynamics and symmetries in light nuclei
Directory of Open Access Journals (Sweden)
Freer Martin
2016-01-01
Full Text Available Many light nuclei display behaviour that indicates that, rather than behaving as an A-body system of individual nucleons, the degrees of freedom are those of clusters. The appearance of α-particle clustering is most widespread. In the present proceedings the symmetries and dynamics of the nuclei 8Be, 12C and 16O are examined together with some recent experimental measurements.
Synthesis of superheavy nuclei: Obstacles and opportunities
Directory of Open Access Journals (Sweden)
Zagrebaev V.I.
2015-01-01
Full Text Available There are only 3 methods for the production of heavy and superheavy (SH nuclei, namely, fusion reactions, a sequence of neutron capture and beta(- decay and multinucleon transfer reactions. Low values of the fusion cross sections and very short half-lives of nuclei with Z<120 put obstacles in synthesis of new elements. At the same time, an important area of SH isotopes located between those produced in the cold and hot fusion reactions remains unstudied yet. This gap could be filled in fusion reactions of 48Ca with available lighter isotopes of Pu, Am, and Cm. New neutron-enriched isotopes of SH elements may be produced with the use of a 48Ca beam if a 250Cm target would be prepared. In this case we get a real chance to reach the island of stability owing to a possible beta(+ decay of 291114 and 287112 nuclei formed in this reaction with a cross section of about 0.8 pb. A macroscopic amount of the long-living SH nuclei located at the island of stability may be produced by using the pulsed nuclear reactors of the next generation only if the neutron fluence per pulse will be increased by about three orders of magnitude. Multinucleon transfer processes look quite promising for the production and study of neutron-rich heavy nuclei located in upper part of the nuclear map not reachable by other reaction mechanisms. Reactions with actinide beams and targets are of special interest for synthesis of new neutron-enriched transfermium nuclei and not-yet-known nuclei with closed neutron shell N=126 having the largest impact on the astrophysical r-process. The estimated cross sections for the production of these nuclei allows one to plan such experiments at currently available accelerators.
Mechanics of deformable bodies
Sommerfeld, Arnold Johannes Wilhelm
1950-01-01
Mechanics of Deformable Bodies: Lectures on Theoretical Physics, Volume II covers topics on the mechanics of deformable bodies. The book discusses the kinematics, statics, and dynamics of deformable bodies; the vortex theory; as well as the theory of waves. The text also describes the flow with given boundaries. Supplementary notes on selected hydrodynamic problems and supplements to the theory of elasticity are provided. Physicists, mathematicians, and students taking related courses will find the book useful.
Dynamical deformation in heavy ion reactions and the characteristics of quasifission products
Guo, S. Q.; Gao, Y.; Li, J. Q.; Zhang, H. F.
2017-10-01
The investigation of the characteristics of low-energy heavy ion reactions covering both fusion and quasifission is carried out within the dinuclear system (DNS) concept, which is developed to include the deformation variables of fragments in addition to the mass numbers of the fragments, so that the energy dissipation, nucleon exchange, and deformation evolutions of the colliding nuclei as well as their correlations are treated simultaneously, and the potential energy surface of the system is thus reaction-time dependent. The direct consequence of introducing the deformation of fragments as dynamical variables is that one must treat the orientation between the two deformed nuclei. This is solved by introducing a barrier function. It is found that the model can reproduce data about the mass, as well as the total kinetic energy and its dispersion, of the reaction products very well, revealing that the DNS model has a reasonable theoretical foundation and thus can reliably describe the reaction mechanism.
Saturation of Deformation and Identical Bands in Very-Neutron Rich Sr Isotopes
2002-01-01
The present proposal aims at establishing nuclear properties in an isotopic chain showing unique features. These features include the saturation of ground state deformation at its onset and the existence of ground state identical bands in neighbouring nuclei with the same deformation. The measurements should help to elucidate the role played by the proton-neutron residual interaction between orbitals with large spatial overlap, i.e. $\\pi g _{9/2} \
Initial Eccentricity in Deformed 197Au+197Au and 238U+238U Collisions at RHIC
Energy Technology Data Exchange (ETDEWEB)
Filip, Peter; Lednicky, Richard; Masui, Hiroshi; Xu, Nu
2010-07-07
Initial eccentricity and eccentricity fluctuations of the interaction volume created in relativistic collisions of deformed {sup 197}Au and {sup 238}U nuclei are studied using optical and Monte-Carlo (MC) Glauber simulations. It is found that the non-sphericity noticeably influences the average eccentricity in central collisions and eccentricity fluctuations are enhanced due to deformation. Quantitative results are obtained for Au+Au and U+U collisions at energy {radical}s{sub NN} = 200 GeV.
Adipocyte nuclei captured from VAT and SAT.
Ambati, Suresh; Yu, Ping; McKinney, Elizabeth C; Kandasamy, Muthugapatti K; Hartzell, Diane; Baile, Clifton A; Meagher, Richard B
2016-01-01
Obesity-related comorbidities are thought to result from the reprogramming of the epigenome in numerous tissues and cell types, and in particular, mature adipocytes within visceral and subcutaneous adipose tissue, VAT and SAT. The cell-type specific chromatin remodeling of mature adipocytes within VAT and SAT is poorly understood, in part, because of the difficulties of isolating and manipulating large fragile mature adipocyte cells from adipose tissues. We constructed MA-INTACT (Mature Adipocyte-Isolation of Nuclei TAgged in specific Cell Types) mice using the adiponectin (ADIPOQ) promoter (ADNp) to tag the surface of mature adipocyte nuclei with a reporter protein. The SUN1mRFP1Flag reporter is comprised of a fragment of the nuclear transmembrane protein SUN1, the fluorescent protein mRFP1, and three copies of the Flag epitope tag. Mature adipocyte nuclei were rapidly and efficiently immuno-captured from VAT and SAT (MVA and MSA nuclei, respectively), of MA-INTACT mice. MVA and MSA nuclei contained 1,000 to 10,000-fold higher levels of adipocyte-specific transcripts, ADIPOQ, PPARg2, EDNRB, and LEP, relative to uncaptured nuclei, while the latter expressed higher levels of leukocyte and endothelial cell markers IKZF1, RETN, SERPINF1, SERPINE1, ILF3, and TNFA. MVA and MSA nuclei differentially expressed several factors linked to adipogenesis or obesity-related health risks including CEBPA, KLF2, RETN, SERPINE1, and TNFA. The various nuclear populations dramatically differentially expressed transcripts encoding chromatin remodeler proteins regulating DNA cytosine methylation and hydroxymethylation (TETs, DNMTs, TDG, GADD45s) and nucleosomal histone modification (ARID1A, KAT2B, KDM4A, PRMT1, PRMT5, PAXIP1). Remarkably, MSA and MVA nuclei expressed 200 to 1000-fold higher levels of thermogenic marker transcripts PRDM16 and UCP1. The MA-INTACT mouse enables a simple way to perform cell-type specific analysis of highly purified mature adipocyte nuclei from VAT and SAT
Diffeomorphic Statistical Deformation Models
DEFF Research Database (Denmark)
Hansen, Michael Sass; Hansen, Mads/Fogtman; Larsen, Rasmus
2007-01-01
In this paper we present a new method for constructing diffeomorphic statistical deformation models in arbitrary dimensional images with a nonlinear generative model and a linear parameter space. Our deformation model is a modified version of the diffeomorphic model introduced by Cootes et al....... The modifications ensure that no boundary restriction has to be enforced on the parameter space to prevent folds or tears in the deformation field. For straightforward statistical analysis, principal component analysis and sparse methods, we assume that the parameters for a class of deformations lie on a linear...... manifold and that the distance between two deformations are given by the metric introduced by the L2-norm in the parameter space. The chosen L2-norm is shown to have a clear and intuitive interpretation on the usual nonlinear manifold. Our model is validated on a set of MR images of corpus callosum...
Study of the pairing force in nuclei; Etude de la force d'appariement dans les noyaux
Energy Technology Data Exchange (ETDEWEB)
Duguet, T
1999-01-01
This work is dedicated to the study of the pairing potential for the nuclei in the stability valley and for the super-deformed isotope groups. The purpose is to propose a pairing force that could be considered as a reference in order to explore the exotic nuclei on safer basis. The domain on which the potential parameters have been studied is defined by: ecut = 5 {+-} 2 MeV, dcut = 0.5 MeV, V{sub 0} = 1000 {+-} 200 MeV for 1 cut, V{sub 0} = 1200 {+-} 200 MeV for 2 cuts. As for the choice of nuclei 3 crosses in the (N,Z) plane have been defined, each centered around a doubly magic isotope: N=Z=28, N=Z=50 and N=Z=82. The results are presented for the nuclei around Ni{sup 56}. It is shown that the best choice for potential parameters is V{sub 0} = 1000 MeV and ecut = 4 MeV, but the pairing effect remains underestimated for the nuclei between N=28 and N=32. For the nuclei N {<=} 26 or N {>=} 38 the disagreement is more important and it requires more than an optimization of the pairing effect for being corrected, the causes of the discrepancy seem to be an insufficient mean field and a lack of accuracy in the Hartree-Fock part. (A.C.)
Deformable bag model of hadrons, 1
Energy Technology Data Exchange (ETDEWEB)
Ui, Haruo; Saito, Koich
1983-05-01
As a generalization of the MIT spherical bag model, we construct the spheroidal bag model of hadron with an arbitrary eccentricity. This generalization is made by slightly modifying the MIT linear boundary condition: The linear boundary condition is examined in detail. Our model always satisfies two necessary requirements of the MIT bag model - i.e., n.j = 0, no quark colour flux leaves the bag, and q-barq = 0, the scalar density of quark should vanish on the bag surface- and it reduces to the MIT spherical bag model in the limit of zero-eccentricity. Lagrangian formalism of our model is briefly described. The eigenfrequencies of a single massless quark confined in this spheroidal bag are numerically calculated. We obtain the level-splitting of the excited quark orbits, which is just analogous to the well-known Nilsson's splitting of single particle orbits in deformed nuclei. By using the numerical results of the lowest orbit, the effect of the bag-deformation on the mass of low-lying hadrons is estimated. It is found that, although the spherical bag is stable, the quark bag is extremely soft against the quadrupole deformation. Brief discussions are added on the mechanisms which make the spherical bag more stable.
Electron scattering and reactions from exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Karataglidis, S. [University of Johannesburg, Department of Physics, Auckland Park (South Africa); University of Melbourne, School of Physics, Victoria (Australia)
2017-04-15
The SCRIT and FAIR/ELISe experiments are the first to attempt to measure directly electron scattering form factors from nuclei far from stability. This will give direct information for the (one-body) charge densities of those systems, about which there is little information available. The SCRIT experiment will be taking data for medium-mass exotic nuclei, while the electron-ion collider at ELISe, when constructed, will be able to measure form factors for a wide range of exotic nuclei, as available from the radioactive ion beams produced by the FAIR experiment. Other facilities are now being proposed, which will also consider electron scattering from exotic nuclei at higher energies, to study short-range correlations in exclusive reactions. This review will consider all available information concerning the current status (largely theoretical) of electron scattering from exotic nuclei and, where possible, complement such information with equivalent information concerning the neutron densities of those exotic systems, as obtained from intermediate energy proton scattering. The issue of long- and short-range correlations will be discussed, and whether extending such studies to the exotic sector will elicit new information. (orig.)
Microscopic description of low-lying M1 excitations in odd-mass actinide nuclei
Energy Technology Data Exchange (ETDEWEB)
Tabar, Emre, E-mail: etabar@sakarya.edu.tr [Physics Department, Sakarya University, 54187 Sakarya (Turkey); Biomedical, Magnetic and Semiconductor Materials Research Center (BIMAS-RC), Sakarya University, 54187 Sakarya (Turkey); Yakut, Hakan, E-mail: hyakut@sakarya.edu.tr [Physics Department, Sakarya University, 54187 Sakarya (Turkey); Biomedical, Magnetic and Semiconductor Materials Research Center (BIMAS-RC), Sakarya University, 54187 Sakarya (Turkey); Kuliev, Ali Akbar [Azerbaijan National Academy of Aviation, Baku (Azerbaijan)
2017-01-15
A restoration method of a broken symmetry which allows self-consistent determination of the separable effective restoration forces is now adapted to odd-mass nuclei in order to restore violated rotational invariance (RI-) of the Quasiparticle Phonon Nuclear Model (QPNM) Hamiltonian. Because of the self-consistency of the method, these effective forces contain no arbitrary parameters. Within RI-QPNM, the properties of the low-lying magnetic dipole excitations in odd-mass deformed {sup 229–233}Th and {sup 233–239}U nuclei have been investigated for the first time. It has been shown that computed fragmentation of the M1 strengths below 4 MeV in these nuclei is much stronger than that in neighboring doubly even {sup 228–232}Th and {sup 232–238}U nuclei. For {sup 235}U the summed M1 strength in the energy range 1.5–2.8 MeV is in agreement with the relevant experimental data where the missing strength was extracted by means of a fluctuation analysis.
Probing surface quantum flows in deformed pygmy dipole modes
Wang, Kai; Kortelainen, M.; Pei, J. C.
2017-09-01
To explore the nature of collective modes in weakly bound nuclei, we have investigated deformation effects and surface flow patterns of isovector dipole modes in a shape-coexisting nucleus, 40Mg. The calculations were done in a fully self-consistent continuum finite-amplitude quasiparticle random phase approximation in a large deformed spatial mesh. An unexpected result of pygmy and giant dipole modes having disproportionate deformation splittings in strength functions was obtained. Furthermore, the transition current densities demonstrate that the long-sought core-halo oscillation in pygmy resonances is collective and compressional, corresponding to the lowest excitation energy and the simplest quantum flow topology. Our calculations show that surface flow patterns become more complicated as excitation energies increase.
Magnesium and Calcium in Isolated Cell Nuclei
Naora, H.; Naora, H.; Mirsky, A. E.; Allfrey, V. G.
1961-01-01
The calcium and magnesium contents of thymus nuclei have been determined and the nuclear sites of attachment of these two elements have been studied. The nuclei used for these purposes were isolated in non-aqueous media and in sucrose solutions. Non-aqueous nuclei contain 0.024 per cent calcium and 0.115 per cent magnesium. Calcium and magnesium are held at different sites. The greater part of the magnesium is bound to DNA, probably to its phosphate groups. Evidence is presented that the magnesium atoms combined with the phosphate groups of DNA are also attached to mononucleotides. There is reason to believe that those DNA-phosphate groups to which magnesium is bound, less than 1/10th of the total, are metabolically active, while those to which histones are attached seem to be inactive. PMID:13727745
Critical and shape-unstable nuclei
Cailliau, M; Husson, J P; Letessier, J; Mang, H J
1973-01-01
The authors' experimental work on the decay of neutron deficient mercury osmium nuclei, some other studies at ISOLDE (CERN) and their first theoretical analysis show that the nuclei around /sup 186/Pt (Z=78, N=108) are at the limit of spherical, oblate, prolate nuclei, have (the even one) their first 0/sup +/ excited states at very low energy; quasi- rotational bands are associated to these states. The energy of this O/sup +/ state in /sup 186-/Pt deviate from the Kumar value: angular shape instability is not enough to explain this result. The authors look at radial shape and pairing fluctuations. The position of the 4p-4n state must also be known. (0 refs).
Statistical ensembles and fragmentation of finite nuclei
Das, P.; Mallik, S.; Chaudhuri, G.
2017-09-01
Statistical models based on different ensembles are very commonly used to describe the nuclear multifragmentation reaction in heavy ion collisions at intermediate energies. Canonical model results are more appropriate for finite nuclei calculations while those obtained from the grand canonical ones are more easily calculable. A transformation relation has been worked out for converting results of finite nuclei from grand canonical to canonical and vice versa. The formula shows that, irrespective of the particle number fluctuation in the grand canonical ensemble, exact canonical results can be recovered for observables varying linearly or quadratically with the number of particles. This result is of great significance since the baryon and charge conservation constraints can make the exact canonical calculations extremely difficult in general. This concept developed in this work can be extended in future for transformation to ensembles where analytical solutions do not exist. The applicability of certain equations (isoscaling, etc.) in the regime of finite nuclei can also be tested using this transformation relation.
Direct non-destructive observation of bulk nucleation in 30% deformed aluminum
DEFF Research Database (Denmark)
West, Stine; Schmidt, Søren; Sørensen, Henning Osholm
2009-01-01
A 30% deformed aluminum sample was mapped non-destructively using three-dimensional X-ray diffraction (3DXRD) before and after annealing to nucleation of recrystallization. Nuclei appeared in the bulk of the sample. Their positions and volumes were determined, and the crystallographic orientations...
High-Resolution Spectroscopy of Sr and Y nuclei near N = Z line
Dendooven, P
2002-01-01
The experiment IS377 aims for investigating the Gamow-Teller strength, isospin symmetry and proton-neutron interaction in the region a nuclide chart where large deformations occur. These studies need detailed information on the low-energy levels in the nuclei. Ground-state masses of Sr and Y nuclei will be studied by using the Penning-trap mass spectrometer ISOLTRAP and the low-energy levels of $^{75}$Rb and $^{78}$Y by $\\beta$-decay spectroscopy. The information obtained can be also used to extend the experimental database for astrophysical rapid proton capture modeling. During 2000 the first step was taken by measuring the masses of $^{76,77}$Sr. The improvement in the absolute mass value of $^{76}$Sr will lead to a significant gain in accuracy of the Gamow-Teller strength involved in the decay. The large deformation of this nucleus has been predicted to alter the strength distribution and this different pattern could be possibly used as a signature of a certain deformation. In addition, $^{76}$Sr, with its...
The Spherical Deformation Model
DEFF Research Database (Denmark)
Hobolth, Asgar
2003-01-01
Miller et al. (1994) describe a model for representing spatial objects with no obvious landmarks. Each object is represented by a global translation and a normal deformation of a sphere. The normal deformation is defined via the orthonormal spherical-harmonic basis. In this paper we analyse...... the spherical deformation model in detail and describe how it may be used to summarize the shape of star-shaped three-dimensional objects with few parameters. It is of interest to make statistical inference about the three-dimensional shape parameters from continuous observations of the surface and from...
Pediatric Thumb Flexion Deformities.
Shreve, Mark; Chu, Alice
2016-03-01
Pediatric trigger thumb and congenital clasped thumb are the two most common pediatric thumb flexion deformities. Both might appear similar, however, they are caused by varying etiologies, and treatment is vastly different. Pediatric trigger thumb is due to a size mismatch of the flexor tendon and the thumb pulley system, develops over time, typically manifests as a locked interphalangeal joint, and is treated with observation or surgical release. Congenital clasped thumb, although presenting in varying degrees of severity, is due to a congenital absence or hypoplasia of one or more of the thumb extensors and is treated with either splinting for supple deformities or surgery for more complex deformities.
Energy Technology Data Exchange (ETDEWEB)
Nadyrbekov, M. S., E-mail: nodirbekov@inp.uz; Bozarov, O. A. [Uzbek Academy of Sciences, Institute of Nuclear Physics (Uzbekistan)
2017-01-15
Reduced probabilities for intra- and interband E2 transitions in excited collective states of even–even lanthanide and actinide nuclei are analyzed on the basis of a model that admits an arbitrary triaxiality. They are studied in detail in the energy spectra of {sup 154}Sm, {sup 156}Gd, {sup 158}Dy, {sup 162,164}Er, {sup 230,232}Th, and {sup 232,234,236,238}U even–even nuclei. Theoretical and experimental values of the reduced probabilities for the respective E2 transitions are compared. This comparison shows good agreement for all states, including high-spin ones. The ratios of the reduced probabilities for the E2 transitions in question are compared with results following from the Alaga rules. These comparisons make it possible to assess the sensitivity of the probabilities being considered to the presence of quadrupole deformations.
Reflections on cavitation nuclei in water
DEFF Research Database (Denmark)
Mørch, Knud Aage
2007-01-01
The origin of cavitation bubbles, cavitation nuclei, has been a subject of debate since the early years of cavitation research. This paper presents an analysis of a representative selection of experimental investigations of cavitation inception and the tensile strength of water. At atmospheric...... pressure, the possibility of stabilization of free gas bubbles by a skin has been documented, but only within a range of bubble sizes that makes them responsible for tensile strengths up to about 1.5 bar, and values reaching almost 300 bar have been measured. However, cavitation nuclei can also be harbored...
Computer Model Of Fragmentation Of Atomic Nuclei
Wilson, John W.; Townsend, Lawrence W.; Tripathi, Ram K.; Norbury, John W.; KHAN FERDOUS; Badavi, Francis F.
1995-01-01
High Charge and Energy Semiempirical Nuclear Fragmentation Model (HZEFRG1) computer program developed to be computationally efficient, user-friendly, physics-based program for generating data bases on fragmentation of atomic nuclei. Data bases generated used in calculations pertaining to such radiation-transport applications as shielding against radiation in outer space, radiation dosimetry in outer space, cancer therapy in laboratories with beams of heavy ions, and simulation studies for designing detectors for experiments in nuclear physics. Provides cross sections for production of individual elements and isotopes in breakups of high-energy heavy ions by combined nuclear and Coulomb fields of interacting nuclei. Written in ANSI FORTRAN 77.
Octupole shapes and shape changes at high spins in the Z approx 58, N approx 88 nuclei
Energy Technology Data Exchange (ETDEWEB)
Nazarewicz, W. (Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States)); Tabor, S.L. (Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States))
1992-05-01
The shapes of rotating Xe, Ba, Ce, Nd, and Sm nuclei (84{le}{ital N}{le}94) are calculated using the cranking model with the Woods-Saxon average potential and pairing. The lightest isotopes of Xe and Ba have nearly spherical ground states, but develop octupole and quadrupole deformations under rotation which remain up to very high spins. The ground states of the heavier isotopes have octupole and quadrupole deformations which persist up to medium spins ({ital I}{approx}12{h bar}). At higher spins, a shape transition is predicted to reflection-symmetric aligned many-quasiparticle configurations.
Shape-based nuclei area of digitized pap smear images
Muhimmah, Izzati; Kurniawan, Rahadian
2012-04-01
Nuclei of the epithelial of Pap smear cells are important risk indicator of cervical cancers. Pathologist uses the changing of the area of the nuclei to determine whether cells are normal or abnormal. It means that having correct measurement of the area of nuclei is important on the pap smears assessment. Our paper present a novel approach to analyze the shape of nuclei in pap smear images and measuring the area of nuclei. We conducted a study to measure the area of nuclei automatically by calculating the number of pixels contained in each of the segmented nuclei. For comparison, we performed measurements of nuclei area using the ellipse area approximation. The result of the t-test confirmed that there were similarity between elliptical area approximation and automatic segmented nuclei-area at 0.5% level of significance.
Decay properties of {sup 256-339}Ds superheavy nuclei
Energy Technology Data Exchange (ETDEWEB)
Santhosh, K.P.; Nithya, C. [Kannur University, School of Pure and Applied Physics, Payyanur, Kerala (India)
2017-09-15
The decay properties of 84 isotopes of darmstadtium superheavy nuclei (Z = 110) have been studied using various theoretical models. The proton emission half-lives, the alpha decay half-lives, the spontaneous fission half-lives and the cluster decay half-lives of all the isotopes are evaluated. The one-proton emission half-lives and the alpha decay half-lives are predicted using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The calculated alpha half-lives are compared with the available experimental results as well as with the predictions of other theoretical models. The predicted half-lives matches well with the experimental results. The one-proton half-lives are also compared with the predictions using other formalisms. The shell-effect-dependent formula of Santhosh et al. has been employed for calculating the spontaneous fission half-lives. A theoretical comparison of spontaneous fission half-lives with four different formalisms is performed. By comparing the one-proton emission half-lives, the alpha decay half-lives and the spontaneous fission half-lives decay modes are predicted for all the isotopes of Ds. It is seen that the isotopes within the range 256 ≤ A ≤ 263 and 279 ≤ A ≤ 339 decay through spontaneous fission and the isotopes 264 ≤ A ≤ 278 exhibit alpha decay. Cluster decay half-lives are calculated using different models including the Coulomb and proximity potential (CPPM), for determining the magicities in the superheavy region. The effect of magicity at N = 184 and N = 202 were confirmed from the plot of log{sub 10}T{sub 1/2} versus neutron number of the daughter nuclei for the emission of different clusters. We hope that the systematic and detailed study of all the possible decay modes of {sup 256-339}Ds using various theoretical models will be helpful in the experimental identification of the isotopes of the element in the future. (orig.)
Extremely deformable structures
2015-01-01
Recently, a new research stimulus has derived from the observation that soft structures, such as biological systems, but also rubber and gel, may work in a post critical regime, where elastic elements are subject to extreme deformations, though still exhibiting excellent mechanical performances. This is the realm of ‘extreme mechanics’, to which this book is addressed. The possibility of exploiting highly deformable structures opens new and unexpected technological possibilities. In particular, the challenge is the design of deformable and bi-stable mechanisms which can reach superior mechanical performances and can have a strong impact on several high-tech applications, including stretchable electronics, nanotube serpentines, deployable structures for aerospace engineering, cable deployment in the ocean, but also sensors and flexible actuators and vibration absorbers. Readers are introduced to a variety of interrelated topics involving the mechanics of extremely deformable structures, with emphasis on ...
Stevens, Jan
2003-01-01
These notes deal with deformation theory of complex analytic singularities and related objects. The first part treats general theory. The central notion is that of versal deformation in several variants. The theory is developed both in an abstract way and in a concrete way suitable for computations. The second part deals with more specific problems, specially on curves and surfaces. Smoothings of singularities are the main concern. Examples are spread throughout the text.
Decay of heavy and superheavy nuclei
Indian Academy of Sciences (India)
2014-03-27
Mar 27, 2014 ... Home; Journals; Pramana – Journal of Physics; Volume 82; Issue 4. Decay of heavy and superheavy nuclei. K P Santhosh. Volume 82 Issue 4 April 2014 ... Author Affiliations. K P Santhosh1. School of Pure and Applied Physics, Kannur University, Swami Anandatheertha Campus, Payyanur 670 327, India ...
Physics of the continuum of borromean nuclei
Energy Technology Data Exchange (ETDEWEB)
Vaagen, J.S.; Rogde, T. [Dept. of Physics, Univ. of Bergen (Norway); Danilin, B.V. [RRC The Kurchatov Inst., Kurchatov, Moscow (Russian Federation); Ershov, S.N. [JINR, Dubna, Moscow (Russian Federation); Thompson, I.J. [Dept. of Physics, Univ. of Surrey, Guildford (United Kingdom); Zhukov, M.V. [Chalmers Univ. of Technology and Goeteborg Univ., Goeteborg (Sweden); RNBT Collaboration
1998-06-01
The continuum states of two-neutron halo nuclei are calculated in the method of hyperspherical harmonics. Using DWIA theory appropriate for dilute halo matter we have probed the structure of the low-lying {sup 6}He continuum via calculations of charge-exchange and inelastic scattering. (orig.)
Borromean structures in medium-heavy nuclei
DEFF Research Database (Denmark)
Hove, Dennis; Fedorov, Dmitri Vladimir; Fynbo, Hans Otto Uldall
2014-01-01
heavy nuclei. We find in all cases that the alpha-particles are located at the surface of the core-nucleus as dictated by Coulomb and centrifugal barriers. The two lowest three-body bound states resemble a slightly contracted 8Be nucleus outside the core. The next two excited states have more complex...
Spectroscopic Studies of Exotic Nuclei at ISOLDE
2002-01-01
Experiment IS50 is designed to: a) Investigate the full range of the @b strength function of heavy (A~$>$~48)~K nuclei b)~Study the decay of isomeric states in n-deficient bromine nuclei (A~=~72 and 70). The heavy K isotopes appeared to have complex decay schemes, including feeding by the @b-decay of levels having open neutron channels (Beta decay energy Q(@b) exceeds neutron binding energy S^n); in addition, a large fraction of the delayed transitions populate excited levels in the daughter nuclei. The allowed @b-decay selects states in the daughter nucleus with wave functions having a large overlap with the initial state. Hence, the @b strength functions, deduced from these deca reveal simple structures correlated to the particle-hole excitation energies in the Ca nuclei. These results are valuable for the application of the shell-model calculations far from stability. The delayed neutron spectra are measured with a large area curved scintillator in coincidence either with high resolution Ge(Li) detectors, ...
Fisica degli atomi e dei nuclei
Bernardini, Carlo
1965-01-01
Evidenza della struttura atomica della materia ; le proprietà degli atomi e la meccanica atomica ; gli atomi e le radiazioni elettromagnetiche ; struttura microscopica dello stato gassoso ; struttura microscopica dello stato liquido ; struttura microscopica della stato solido ; proprietà elettriche e magnetiche delle sostanze ; proprietà dei nuclei degli atomi ; le particelle elementari.
Nuclear Shell Structure and Beta Decay I. Odd A Nuclei II. Even A Nuclei
Mayer, M.G.; Moszkowski, S.A.; Nordheim, L.W.
1951-05-01
In Part I a systematics is given of all transitions for odd A nuclei for which sufficiently reliable data are available. The allowed or forbidden characters of the transitions are correlated with the positions of the initial and final odd nucleon groups in the nuclear shell scheme. The nuclear shells show definite characteristics with respect to parity of the ground states. The latter is the same as the one obtained from known spins and magnetic moments in a one-particle interpretation. In Part II a systematics of the beta transitions of even-A nuclei is given. An interpretation of the character of the transitions in terms of nuclear shell structure is achieved on the hypothesis that the odd nucleon groups have the same structure as in odd-A nuclei, together with a simple coupling rule between the neutron and proton groups in odd-odd nuclei.
Generator coordinate method and superdeformation in A=190 nuclei
Energy Technology Data Exchange (ETDEWEB)
Dancer, H.; Perres, S.; Bonche, P.; Flocard, H.; Heenen, P.-H.; Meyer, J. E-mail: jmeyer@ipnl.in2p3.fr; Meyer, M
1999-07-26
The Generator Coordinate Method with particle number projection using a set of Hartree-Fock plus BCS states is applied to the superdeformed even-even Hg and Pb isotopes. The q{sub 30} and q{sub 32} octupole vibrations are investigated in even-even Hg and Pb isotopes. These one-dimensional calculations predict that the collective octupole K{sup {pi}}=0{sup -} excitations are the lowest mode in energy. The electric monopole E0 decay out of superdeformed states is also compared to the electric quadrupole E2 transition rates.
High-K isomers in transactinide nuclei close to N = 162
Energy Technology Data Exchange (ETDEWEB)
Prassa, V., E-mail: vprassa@phy.hr; Nikšić, T.; Vretenar, D. [Physics Department, Faculty of science, University of Zagreb, 10000 Zagreb (Croatia); Lu, Bing-Nan [Institut fur Kernphysik, Institute for Advanced Simulation, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Ackermann, D. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany)
2015-10-15
Transactinide nuclei around neutron number N = 162 display axially deformed equilibrium shapes, as shown in our previous analysis [1] of constrained mean-field energy surfaces and collective excitation spectra. In the present study we are particularly interested in the occurrence of high-K isomers in the axially deformed isotopes of Rf (Z = 104), Sg (Z = 106), Hs (Z = 108), and Ds (Z = 110), with neutron number N = 160 − 166 and the effect of the N=162 closure on the structure and distribution of two-quasiparticle (2qp) states. The evolution of high-K isomers is analysed in a self-consistent axially-symmetric relativistic Hartree-Bogoliubov calculation using the blocking approximation with time-reversal symmetry breaking.
Probing the density tail of radioactive nuclei with antiprotons
Obertelli, Alexandre; Uesaka, Tomohiro; Corsi, Anna; Pollacco, Emmanuel; Flavigny, Freddy
2017-01-01
We propose an experiment to determine the proton and neutron content of the radial density tail in short-lived nuclei. The objectives are to (i) to evidence new proton and neutron halos, (ii) to understand the development of neutron skins in medium-mass nuclei, (iii) to provide a new observable that characterises the density tail of short-lived nuclei.
Directory of Open Access Journals (Sweden)
Fabiano Stumpf Lutz
2014-12-01
Full Text Available Objective: To present the deformities and evaluate the results of their treatment. Methods: Retrospective study of patients with deformity following surgical access to the spinal canal. Fifteen patients who met the inclusion criteria were included. Patients without complete data in medical records were excluded. Results: Fourteen patients underwent surgical treatment and one patient received conservative treatment with vest type TLSO. The average angle of kyphosis correction was 87° preoperatively to 38° postoperatively, while the associated scoliosis correction was 69° preoperatively to 23° postoperatively. Conclusions: The prevention of deformity should be emphasized to avoid laminectomy alone, while laminoplasty should be the procedure of choice for canal access in surgeries where there is no need for resection of the posterior elements.
Breast deformities and mastopexy.
Nahabedian, Maurice Y
2011-04-01
LEARNING OBJECTIONS: After reviewing this article, the participant should be able to: 1. Appreciate the diversity of approaches for the correction of breast deformities and mastopexy. 2. Review the salient literature. 3. Understand patient selection criteria and indications. Breast deformities and mastopexy continue to challenge plastic surgeons. Deformities such as Poland syndrome, tuberous breast, gynecomastia, and other congenital conditions are uncommon; therefore, management experience is often limited. Various techniques have been described, with no general consensus regarding optimal management. Mastopexy has become more common and is performed both with and without augmentation mammaplasty. However, a variety of techniques are available, and a thorough understanding of the indications, patient selection criteria, and techniques is important to optimize outcomes. This article will review these and other conditions to provide a better understanding of the current available data and evidence for these operations.
Autogenous Deformation of Concrete
DEFF Research Database (Denmark)
Autogenous deformation of concrete can be defined as the free deformation of sealed concrete at a constant temperature. A number of observed problems with early age cracking of high-performance concretes can be attributed to this phenomenon. During the last 10 years , this has led to an increased...... focus on autogenous deformation both within concrete practice and concrete research. Since 1996 the interest has been significant enough to hold international, yearly conferences entirely devoted to this subject. The papers in this publication were presented at two consecutive half-day sessions...... at the American Concrete Institute’s Fall Convention in Phoenix, Arizona, October 29, 2002. All papers have been reviewed according to ACI rules. This publication, as well as the sessions, was sponsored by ACI committee 236, Material Science of Concrete. The 12 presentations from 8 different countries indicate...
Energy Technology Data Exchange (ETDEWEB)
Bavaro, A. (Soliveri SpA, Caravaggio (Italy))
1990-02-01
Types and causes of heat treatement derived isotropic and anisotropic dilatancies in ferrous materials are reviewed. The concepts are developed in such a way as to allow extension to all materials exhibiting martensitic tempering behaviour. This paper intends to illustrate the basic processes of dimensional variations undergone by the materials under heat treatments. The parametric analysis includes an analysis of the interactions amongst the parameters themselves. The relative importance of each parameter is assessed in order to determine methods to attenuate deformation action. Simplified examples are offered to provide technicians explanations as to why specific deformations occur and indications on improved materials working techniques.
Nail Deformities and Injuries.
Tucker, James Rory J
2015-12-01
A variety of nail deformities commonly presents in the primary care office. An understanding of nail anatomy coupled with inspection of the nails at routine office visits can reveal undetected disorders. Some problems are benign, and treatment should be attempted by the primary care provider, such as onychomycosis, paronychia, or ingrown toenails. For conditions such as benign melanonychia, longitudinal ridges, isolated Beau lines, and onycholysis, clinicians may offer reassurance to patients who are concerned about the change in their nails. For deformities such as early pterygium or clubbing, a thorough evaluation and referral to an appropriate specialist may be warranted. Copyright © 2015 Elsevier Inc. All rights reserved.
Joining by plastic deformation
DEFF Research Database (Denmark)
Mori, Ken-ichiro; Bay, Niels; Fratini, Livan
2013-01-01
As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating opportuni......As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating...
Antiproton Induced Fission and Fragmentation of Nuclei
2002-01-01
The annihilation of slow antiprotons with nuclei results in a large highly localized energy deposition primarily on the nuclear surface. \\\\ \\\\ The study of antiproton induced fission and fragmentation processes is expected to yield new information on special nuclear matter states, unexplored fission modes, multifragmentation of nuclei, and intranuclear cascades.\\\\ \\\\ In order to investigate the antiproton-nucleus interaction and the processes following the antiproton annihilation at the nucleus, we propose the following experiments: \\item A)~Measurement of several fragments from fission and from multifragmentation in coincidence with particle spectra, especially neutrons and kaons. \\item B)~Precise spectra of $\\pi$, K, n, p, d and t with time-of-flight techniques. \\item C)~Installation of the Berlin 4$\\pi$ neutron detector with a 4$\\pi$ Si detector placed inside for fragments and charged particles. This yields neutron multiplicity distributions and consequently distributions of thermal excitation energies and...
[Bilateral infarction of the caudate nuclei].
Mrabet, A; Mrad-Ben Hammouda, I; Abroug, Z; Smiri, W; Haddad, A
1994-01-01
We report the case of a 57-year-old right-handed woman, with a history of hypertension, who, in February 1990, suddenly developed behavioral and cognitive abnormalities. Prior to the onset of her illness she had been normal. On examination, neuropsychological testing (Wechsler Mental Test, Wechsler Adult Intelligence Scale Revised, Knox Cube Test) elicited attention abnormalities, decreased recent memory, apathy, reduced spontaneity and initiative and left hemiparesia. CT scan showed small low density areas in the head of both caudate nuclei and right internal capsule, indicating infarction. Two years later, the deficit had partially resolved. Apathy persisted; psychometry showed an IQ of 57. Bilateral damage to the head of the caudate nuclei disrupt cortical-subcortical connections. The caudate nucleus is an essential component of basal ganglia-thalamo-cortical circuitry and its contribution to cognitive functions and behavior appears to be important.
Isospin Mixing In N $\\approx$ Z Nuclei
Srnka, D; Versyck, S; Zakoucky, D
2002-01-01
Isospin mixing in N $\\approx$ Z nuclei region of the nuclear chart is an important phenomenon in nuclear physics which has recently gained theoretical and experimental interest. It also forms an important nuclear physics correction in the precise determination of the $ft$-values of superallowed 0$^+ \\rightarrow 0^+ \\beta$- transitions. The latter are used in precision tests of the weak interaction from nuclear $\\beta$- decay. We propose to experimentally measure isospin mixing into nuclear ground states in the N $\\approx$ Z region by determining the isospin forbidden Fermi-component in the Gamow-Teller dominated $J^{\\pi} \\rightarrow J^{\\pi} \\beta$- transitions through the observation of anisotropic positron emission from oriented nuclei. First measurements were carried out with $^{71}$As and are being analyzed now.
Weighing the evidence for clustering in nuclei
Jenkins, David; Courtin, Sandrine
2015-03-01
Clustering in nuclei is a long-standing topic in nuclear physics. While it has attracted much experimental and theoretical attention over the years, it is a model which is still controversial in terms of whether such clustering can be clearly delineated and separated from the complexity of nuclear structure described within more conventional nuclear models. In this sense, there is still ambiguity in terms of the uniqueness and relevance of the clustering description. What is often not clearly articulated is what would provide the most compelling evidence for clustering in different contexts. As a means of illustrating these issues, two strands of this topic will be discussed: alpha clustering in light nuclei and clustering in the 12C+12C system. Recent work in these areas will be reviewed and scope for future work will be highlighted.
Heavy Nuclei Photofission at Intermediate Energies
Deppman, A; Guimaraes, V; Demekhina, N A; Karapetyan, G S
2013-01-01
In the present work the yields of fission fragments, from Bremsstrahlung induced fission of 232Th, 238U targets, were reproduced by CRISP model calculations, to which a multimodal fission option had been added. An extension of the calculation to the properties of the fission products is presented. Dividing the fissioning nuclei according to their fissionability, an approach which accounts for the contribution of symmetric and asymmetric fission is introduced. It allows to calculate the main parameters of the fission fragment charge distribution: the most probable charge for a given fission product mass chain and the width parameter. Furthermore, it reproduces the features of fragment mass distribution, and evaluates the fissility of fissioning nuclei in photon-induced fission. A comparison between the results of this calculation and experimental data is accomplished.
Collective properties of drip-line nuclei
Energy Technology Data Exchange (ETDEWEB)
Hamamoto, I. [Univ. of Lund (Sweden); Sagawa, H. [Univ. of Aizu, Fukushima (Japan)
1996-12-31
Performing the spherical Hartree-Fock (HF) calculations with Skyrme interactions and, then, using RPA solved in the coordinate space with the Green`s function method, the authors have studied the effect of the unique shell structure as well as the very low particle threshold on collective modes in drip line nuclei. In this method a proper strength function in the continuum is obtained, though the spreading width of collective modes is not included. They have examined also one-particle resonant states in the obtained HF potential. Unperturbed particle-hole (p-h) response functions are carefully studied, which contain all basic information on the exotic behaviour of the RPA strength function in drip line nuclei.
Mesic nuclei with a heavy antiquark
Yamaguchi, Yasuhiro; Yasui, Shigehiro
2017-09-01
The binding of a hadron and a nucleus is a topic of great interest for investigating hadron properties. In the heavy-flavor region, attraction between a P(=\\bar{D},B) meson and a nucleon N can appear, where PN-P^\\ast N mixing plays an important role in relation to the heavy-quark spin symmetry. The attraction can produce exotic heavy mesic nuclei that are stable against strong decay. We study an exotic system where the \\bar{D} (B) meson and nucleus are bound. The meson-nucleus interaction is given by a folding potential with single-channel PN interaction and the nucleon number distribution function. By solving the Schrödinger equations of the heavy meson and the nucleus, we obtain several bound and resonant states for nucleon number A=16,\\ldots,208. The results indicate the possible existence of exotic mesic nuclei with a heavy antiquark.
Deeply virtual Compton scattering off nuclei
Energy Technology Data Exchange (ETDEWEB)
Voutier, Eric
2009-01-01
Deeply virtual Compton scattering (DVCS) is the golden exclusive channel for the study of the partonic structure of hadrons, within the universal framework of generalized parton distributions (GPDs). This paper presents the aim and general ideas of the DVCS experimental program off nuclei at the Jefferson Laboratory. The benefits of the study of the coherent and incoherent channels to the understanding of the EMC (European Muon Collaboration) effect are discussed, along with the case of nuclear targets to access neutron GPDs.
S-wave pion absorption by nuclei
Energy Technology Data Exchange (ETDEWEB)
Hachenberg, F.; Huefner, J.; Pirner, H.J.
1976-01-01
The absorption of pions by nuclei leads to an imaginary part in the optical potential for pionic atoms. The imaginary part is calculated by assuming the rescattering mechanism to dominate. The pion scatters off-shell by one nucleon and is absorbed by a second one. The ..pi..N scattering amplitude is constructed from a field theoretical model. Its off-mass shell properties prove important to reproduce the data.
Tagged EMC Measurements on Light Nuclei
Armstrong, Whitney; Arrington, John; Cloet, Ian; Hafidi, Kawtar; Hattawy, Mohammad; Potteveld, David; Reimer, Paul; Riordan, Seamus; Yi, Z.; Ball, Jacques; Defurne, Maxime; Garcon, Michel; Moutarde, Herve; Procureur, Sebastien; Sabatie, Franck
2017-01-01
We propose to measure tagged deep inelastic scattering from light nuclei (deuterium and $^4$He) by detecting the low energy nuclear spectator recoil (p, $^3$H and $^3$He) in addition to the scattered electron. The proposed experiment will provide stringent tests leading to clear differentiation between the many models describing the EMC effect, by accessing the bound nucleon virtuality through its initial momentum at the point of interaction. Indeed, conventional nuclear physics explanations ...
AMS with light nuclei at small accelerators
Stan-Sion, C.; Enachescu, M.
2017-06-01
AMS applications with lighter nuclei are presented. It will be shown how Carbon-14, Boron-10, Beryllium-10, and Tritium-3 can be used to provide valuable information in forensic science, environmental physics, nuclear pollution, in material science and for diagnose of the plasma confinement in fusion reactors. Small accelerators are reliable, efficient and possess the highest ion beam transmissions that confer high precision in measurements.
Synthesis of Magnetized Nuclei at Supernova Explosion
Kondratyev, V. N.; Nurtayeva, U. M.; Zhomartova, A. Zh.; Mishenina, T. V.
Influence of magnetorotational instabilities in astrophysical plasma at supernova explosion on synthesis of chemical elements is investigated. At field strength less than 10 teratesla nuclear magnetic susceptibility exhibits linear regime with enhanced nuclear binding energy for open shell nuclei. Effects of ultra-strong nuclear magnetization are demonstrated to enhance the portion of titanium product. The relation to an excess of titanium isotopes revealed from the Integral mission data and galactic chemical evolution is discussed.
Interaction of nuclei at high energies
Energy Technology Data Exchange (ETDEWEB)
Steiner, H.
1977-08-01
A review is given of recent theoretical and experimental developments in the study of collisions between energetic nuclei. Single particle inclusive spectra is first discussed, citing results of selected experiments and reviewing briefly some of the models involved in explaining the data. Problems in the study of multiparticle final states are then examined. Finally, some other experiments are mentioned whose methods or physics objectives are slightly different from those discussed previously. (SDF)
Light nuclei production in heavy ion collisions
Khan, K H; Wazir, Z; Khan, E U; Haseeb, Mahnaz Q; Ajaz, M
2009-01-01
Light nuclei production as a result of nuclear coalescence effect can give some signals on final state of Quark Gluon Plasma formation. We are studying the behavior of nuclear modification factor as a function of different variables using the simulated data coming from the FASTMC generator. This data is necessary to extract information on coalescence mechanism from experimental data on high energy nuclear-nuclear interactions.
Marginally Deformed Starobinsky Gravity
DEFF Research Database (Denmark)
Codello, A.; Joergensen, J.; Sannino, Francesco
2015-01-01
We show that quantum-induced marginal deformations of the Starobinsky gravitational action of the form $R^{2(1 -\\alpha)}$, with $R$ the Ricci scalar and $\\alpha$ a positive parameter, smaller than one half, can account for the recent experimental observations by BICEP2 of primordial tensor modes....
Unified description of pf-shell nuclei by the Monte Carlo shell model calculations
Energy Technology Data Exchange (ETDEWEB)
Mizusaki, Takahiro; Otsuka, Takaharu [Tokyo Univ. (Japan). Dept. of Physics; Honma, Michio
1998-03-01
The attempts to solve shell model by new methods are briefed. The shell model calculation by quantum Monte Carlo diagonalization which was proposed by the authors is a more practical method, and it became to be known that it can solve the problem with sufficiently good accuracy. As to the treatment of angular momentum, in the method of the authors, deformed Slater determinant is used as the basis, therefore, for making angular momentum into the peculiar state, projected operator is used. The space determined dynamically is treated mainly stochastically, and the energy of the multibody by the basis formed as the result is evaluated and selectively adopted. The symmetry is discussed, and the method of decomposing shell model space into dynamically determined space and the product of spin and isospin spaces was devised. The calculation processes are shown with the example of {sup 50}Mn nuclei. The calculation of the level structure of {sup 48}Cr with known exact energy can be done with the accuracy of peculiar absolute energy value within 200 keV. {sup 56}Ni nuclei are the self-conjugate nuclei of Z=N=28. The results of the shell model calculation of {sup 56}Ni nucleus structure by using the interactions of nuclear models are reported. (K.I.)
Flow cytometry of DNA in mouse sperm and testis nuclei
Energy Technology Data Exchange (ETDEWEB)
Meistrich, M.L. (Univ. of Texas, Houston); Lake, S.; Steinmetz, L.L.; Gledhill, B.L.
1978-01-01
Mutations that occur in spermatogenic cells may be expressed as changes in DNA content, but developmentally-dependent alteration of its staining properties complicates the quantitation of DNA in individual germ cells. These alterations have been studied with flow cytometric techniques. Nuclei from mouse testis cells and sperm were stained by the acriflavine--Feulgen method. The fluorescence intensity frequency distribution of nuclei of testis cells was characterized by 2 major and 5 minor peaks. Nuclei sorted from the various peaks with a fluorescence-activated cell sorter were identified microscopically. These data were confirmed by generation of peaks with nuclei prepared from cell suspensions enriched in specific cell types. One of the major peaks corresponded to round spermatid nuclei. The other major peak, located at 0.6 of the fluorescence intensity of the round nuclei, corresponded to elongated spermatid nuclei. Purified nuclei of epididymal and vas deferens spermatozoa displayed asymmetric fluorescence distributions. A minor peak at 0.8 the intensity of the round spermatid nuclei was tentatively assigned to elongating spermatids. 2 of the minor peaks, located at 1.7 and 2.0 times the fluorescence intensity of the round nuclei, corresponded to clumps of 2 haploid and diploid nuclei.
Deformation of chlorite in naturally deformed low-grade rocks
Bons, A.J.
1988-01-01
The intracrystalline deformation of chlorite in naturally deformed low-grade rocks was investigated with transmission electron microscopy (TEM). As in other phyllosilicates, the deformation of chlorite is dominated by the (001) slip plane. Slip along this plane is very easy through the generation
From heavy nuclei to super-heavy nuclei; Des noyaux lourds aux super-lourds
Energy Technology Data Exchange (ETDEWEB)
Theisen, Ch
2003-01-01
The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)
Postural deformities in Parkinson's disease
Doherty, K.M.; Warrenburg, B.P.C. van de; Peralta, M.C.; Silveira-Moriyama, L.; Azulay, J.P.; Gershanik, O.S.; Bloem, B.R.
2011-01-01
Postural deformities are frequent and disabling complications of Parkinson's disease (PD) and atypical parkinsonism. These deformities include camptocormia, antecollis, Pisa syndrome, and scoliosis. Recognition of specific postural syndromes might have differential diagnostic value in patients
Energy Technology Data Exchange (ETDEWEB)
Moller, Peter [Los Alamos National Laboratory; Pereira, J [MSU; Hennrich, S [MSU; Aprahamian, A [UNIV OF NOTRE DAME; Arndt, O [GERMANY; Becerril, A [MSU; Elliot, T [MSU; Estrade, A [MSU; Galaviz, D [MSU; Kessler, R [UNIV MAINZ; Kratz, K - L [GERMANY; Lorusso, G [MSU; Mantica, P F [MSU; Matos, M [MSU; Montes, F [MSU; Pfeiffer, B [UNIV MAINZ; Schatz, F [MSU; Schnorrenberger, L [GERMANY; Smith, E [MSU; Stolz, A [MSU; Quinn, M [UNIV OF NOTRE DAME; Walters, W B [UNIV OF MARYLAND; Wohr, A [UNIV OF NOTRE DAME
2009-01-01
Measurements of the {beta}-decay properties of A {approx}< 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr and {sup 108,111}Mo, along with ,B-delayed neutron emission probabilities of 104Y, 109,11OMo and upper limits for 105Y, 103-107Zr and 108,111 Mo have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to analyze the ground-state deformation of these nuclei.
Energy Technology Data Exchange (ETDEWEB)
Savajols, H.
1996-05-13
This work concerns the study of the nuclear superdeformation phenomenon in the rare earth region (A {approx} 150). The superdeformed (SD) states in Gadolinium and Dysprosium isotopes were produced via heavy-ion induced reactions and studied with the (EUROGAM EUROpean GAmma-ray Microscope) gamma multidetector array. Precise level attenuation method (DSAM). From the derived quadrupole moments, we find large differences in deformation between the yrast bands in neighbour nuclei explained in terms of the case of nuclei corresponding to an axis ratio of 2:1, the shell gaps are not fixed at a specific particle number and deformation. Furthermore the present results indicate that the deformations associated with identical bands are different supporting the picture that mass and deformation changes tend to compensate in SB bands with the same moments of inertia. (author). 114 refs.
Cosmetic and Functional Nasal Deformities
... nasal complaints. Nasal deformity can be categorized as “cosmetic” or “functional.” Cosmetic deformity of the nose results in a less ... taste , nose bleeds and/or recurrent sinusitis . A cosmetic or functional nasal deformity may occur secondary to ...
Nuclei at extreme conditions. A relativistic study
Energy Technology Data Exchange (ETDEWEB)
Afanasjev, Anatoli [Mississippi State Univ., Mississippi State, MS (United States)
2014-11-14
The major goals of the current project were further development of covariant density functional theory (CDFT), better understanding of its features, its application to different nuclear structure and nuclear astrophysics phenomena and training of graduate and undergraduate students. The investigations have proceeded in a number of directions which are discussed in detail in the part “Accomplishments” of this report. We have studied the role of isovector and isoscalar proton-neutron pairings in rotating nuclei; based on available experimental data it was concluded that there are no evidences for the existence of isoscalar proton-neutron pairing. Generalized theoretical approach has been developed for pycnonuclear reaction rates in the crust of neutron stars and interior of white dwarfs. Using this approach, extensive database for considerable number of pycnonuclear reactions involving stable and neutron-rich light nuclei has been created; it can be used in future for the study of various nuclear burning phenomena in different environments. Time-odd mean fields and their manifestations in terminating states, non-rotating and rotating nuclei have been studied in the framework of covariant density functional theory. Contrary to non-relativistic density functional theories these fields, which are important for a proper description of nuclear systems with broken time-reversal symmetry, are uniquely defined in the CDFT framework. Hyperdeformed nuclear shapes (with semi-axis ratio 2.5:1 and larger) have been studied in the Z = 40-58 part of nuclear chart. We strongly believe that such shapes could be studied experimentally in the future with full scale GRETA detector.
Effective field theory description of halo nuclei
Hammer, H.-W.; Ji, C.; Phillips, D. R.
2017-10-01
Nuclear halos emerge as new degrees of freedom near the neutron and proton driplines. They consist of a core and one or a few nucleons which spend most of their time in the classically-forbidden region outside the range of the interaction. Individual nucleons inside the core are thus unresolved in the halo configuration, and the low-energy effective interactions are short-range forces between the core and the valence nucleons. Similar phenomena occur in clusters of 4He atoms, cold atomic gases near a Feshbach resonance, and some exotic hadrons. In these weakly-bound quantum systems universal scaling laws for s-wave binding emerge that are independent of the details of the interaction. Effective field theory (EFT) exposes these correlations and permits the calculation of non-universal corrections to them due to short-distance effects, as well as the extension of these ideas to systems involving the Coulomb interaction and/or binding in higher angular-momentum channels. Halo nuclei exhibit all these features. Halo EFT, the EFT for halo nuclei, has been used to compute the properties of single-neutron, two-neutron, and single-proton halos of s-wave and p-wave type. This review summarizes these results for halo binding energies, radii, Coulomb dissociation, and radiative capture, as well as the connection of these properties to scattering parameters, thereby elucidating the universal correlations between all these observables. We also discuss how Halo EFT's encoding of the long-distance physics of halo nuclei can be used to check and extend ab initio calculations that include detailed modeling of their short-distance dynamics.
The superdeformation phenomenon in atomic nuclei
Meyer, M.; Vivien, J. P.
After the discovery of discrete rotational bands corresponding to superdeformed nuclei with spin around 60h, the study of the structure of these nuclei over the last five years has witnessed a significant expansion in physical understanding with the emergence of new phenomena and in a technical development with the construction of sophisticated apparatus to examine these nuclei. On the eve of the approaching operation of news detectors such as EUROGAM resulting from a French-British collaboration,or the American GAMMASPHERE, this article discusses the present state of knowledge on superdeformation and exposes the theoretical basis as well as recent experimental results in the field. Avec la découverte de bandes de rotations discrètes correspondant à des noyaux superdéformés ayant des moments angulaires avoisinant 60h, l'étude de la structure de ces noyaux connait depuis les cinq dernières années un essor important tant sur le plan de la physique avec l'apparition de phénomènes nouveaux que sur le plan de la technique avec le développement d'appareillages sophistiqués pour scruter ces noyaux. A la veille de l'entrée en fonction de nouveaux détecteurs comme EUROGAM issu d'une collaboration Franco-Britannique ou GAMMASPHERE résultant des efforts des laboratoires Americains, cet article fait le point des connaissances actuelles sur la superdéformation et relate les acquis théoriques ainsi que les resultats expérimentaux accumulés récemment dans ce domaine.
Latham, Kerry; Fernandez, Sarah; Iteld, Larry; Panthaki, Zubin; Armstrong, Milton B; Thaller, Seth
2006-05-01
Congenital breast anomalies represent a relatively common set of disorders encountered by pediatric plastic surgeons with a spectrum of severity that ranges widely from the relatively benign polythelia to the very complex disorders such as Poland's syndrome and tuberous breast deformities. While the former can be treated in a single surgical setting with minimal morbidity, the more complicated disorders often require a staged reconstructive algorithm. Some disorders also require a multidisciplinary management for both workup and management. Although rarely a source of functional morbidity, these physical deformities are often a significant source of psychological stress for the adolescent male or female who feels alienated from their peers. The purpose of this article is to review the most common congenital breast disorders including the diagnosis, workup, and management especially the timing of surgical intervention as guided by normal developmental milestones.
[Babies with cranial deformity].
Feijen, Michelle M W; Claessens, Edith A W M Habets; Dovens, Anke J Leenders; Vles, Johannes S; van der Hulst, Rene R W J
2009-01-01
Plagiocephaly was diagnosed in a baby aged 4 months and brachycephaly in a baby aged 5 months. Positional or deformational plagio- or brachycephaly is characterized by changes in shape and symmetry of the cranial vault. Treatment options are conservative and may include physiotherapy and helmet therapy. During the last two decades the incidence of positional plagiocephaly has increased in the Netherlands. This increase is due to the recommendation that babies be laid on their backs in order to reduce the risk of sudden infant death syndrome. We suggest the following: in cases of positional preference of the infant, referral to a physiotherapist is indicated. In cases of unacceptable deformity of the cranium at the age 5 months, moulding helmet therapy is a possible treatment option.
The Structure of Nuclei Far from Stability
Energy Technology Data Exchange (ETDEWEB)
Zganjar, E.F.
1999-02-25
From among a number of important nuclear structure results that have emerged from our research program during the past few years, two stand out as being of extra significance. These are: (a) the identification of a diabatic coexisting structure in {sup 187}Au which arises solely from differences in proton occupation of adjacent oscillator shells, and (b) the realization of a method for estimating EO strength in nuclei and the resulting prediction that the de-excitation of superdeformed bands may proceed, in some cases, by strong EO transitions.
Probing Chiral Interactions in Light Nuclei
Energy Technology Data Exchange (ETDEWEB)
Nogga, A; Barrett, B R; Meissner, U; Witala, H; Epelbaum, E; Kamada, H; Navratil, P; Glockle, W; Vary, J P
2004-01-08
Chiral two- and three-nucleon interactions are studied in a few-nucleon systems. We investigate the cut-off dependence and convergence with respect to the chiral expansion. It is pointed out that the spectra of light nuclei are sensitive to the three-nucleon force structure. As an example, we present calculations of the 1{sup +} and 3{sup +} states of {sup 6}Li using the no-core shell model approach. The results show contributions of the next-to-next-to-leading order terms to the spectra, which are not correlated to the three-nucleon binding energy prediction.
Onset of chaos in rapidly rotating nuclei
Energy Technology Data Exchange (ETDEWEB)
Aberg, S. (Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, TN (USA) Department of Mathematical Physics, Lund Institute of Technology, P.O. Box 118, S-22100 Lund (Sweden))
1990-06-25
The onset of chaos is investigated for excited, rapidly rotating nuclei, utilizing a schematic two-body residual interaction added to the cranked Nilsson Hamiltonian. Dynamical effects at various degrees of mixing between regularity and chaos are studied in terms of fragmentation of the collective rotational strength. It is found that the onset of chaos is connected to a saturation of the average standard deviation of the rotational strength function. Still, the rotational-damping width may exhibit motional narrowing in the chaotic regime.
Modeling a neutron rich nuclei source
Energy Technology Data Exchange (ETDEWEB)
Mirea, M.; Bajeat, O.; Clapier, F.; Ibrahim, F.; Mueller, A.C.; Pauwels, N.; Proust, J. [Institut de Physique Nucleaire, IN2P3/CNRS, 91 - Orsay (France); Mirea, M. [Institute of Physics and Nuclear Engineering, Tandem Lab., Bucharest (Romania)
2000-07-01
The deuteron break-up process in a suitable converter gives rise to intense neutron beams. A source of neutron rich nuclei based on the neutron induced fission can be realised using these beams. A theoretical optimization of such a facility as a function of the incident deuteron energy is reported. The model used to determine the fission products takes into account the excitation energy of the target nucleus and the evaporation of prompt neutrons. Results are presented in connection with a converter-target specific geometry. (author000.
[Treatment of chin deformities].
Morera Serna, Eduardo; Scola Pliego, Esteban; Mir Ulldemolins, Nuria; Martínez Morán, Alejandro
2008-01-01
Facial beauty depends on the form, proportion and position of its various units. The chin is the most prominent element of the lower third of the face, both in the frontal view and in profile. The surgical approach to chin deformities did not start until the second half of the twentieth century. The development of silicone prostheses and the emergence of sliding genioplasty offered surgeons a whole new range of options to modify the size and position of the chin. We have performed a historical review of chin surgery, the multiple aesthetic analyses available and the advantages and disadvantages of the different alloplastic materials and osteotomies. To do so, a comprehensive search through current scientific literature on the topic has been carried out, focusing on large series, long-term follow-up studies, research in animal models and medical evidence. As happens in almost any topic in facial plastic surgery, no strong evidence useful in ENT practice for handling chin deformities can be found in today's scientific literature. Ethnicity influences the aesthetic analysis; the type and degree of deformity to be corrected will determine the allo-plastic augmentation of the chin or the suitability of osteotomy. Porous polyethylene (Medpor, Porex Surgical, Newman, Ca, USA) and solid silicone (Silastic, Michigan Medical Corporation, Santa Barbara, Ca, USA) show a clear advantage over other alloplastic materials. Moderate-to-severe retrogenia benefits from sliding genioplasty strategies rather than prosthetic enlargement.
Precision measurement of the mass difference between light nuclei and anti-nuclei
Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmed, Ijaz; Ahn, Sang Un; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Ball, Markus; Baltasar Dos Santos Pedrosa, Fernando; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Iii, Ronald John; Belmont Moreno, Ernesto; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biswas, Saikat; Bjelogrlic, Sandro; Blanco, Fernando; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Buxton, Jesse Thomas; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Deisting, Alexander; Deloff, Andrzej; Denes, Ervin Sandor; D'Erasmo, Ginevra; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Engel, Heiko; Erazmus, Barbara Ewa; Erhardt, Filip; Eschweiler, Dominic; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; 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Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacobs, Peter Martin; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Kamal; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Do Won; Kim, Dong Jo; Kim, Hyeonjoong; Kim, Jinsook; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; Kluge, Alexander; Knichel, Michael Linus; 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Lee, Graham Richard; Lee, Seongjoo; Legrand, Iosif; Lehnert, Joerg Walter; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loggins, Vera Renee; Loginov, Vitaly; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Lu, Xianguo; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; 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Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Nattrass, Christine; Nayak, Kishora; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; 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Zyzak, Maksym
2015-08-17
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. This force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons (d) and anti-deuterons ($\\bar{d}$), and $^{3}{\\rm He}$ and $^3\\overline{\\rm He}$ nuclei carried out with the ALICE (A Large Ion Collider Experiment) detector in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Our direct measurement of the mass-over-charge differences confirm CPT invariance to an unprecedented precision in the sector of light nuclei. This funda...
FROM NUCLEAR-MATTER TO FINITE NUCLEI .2. RELATIVISTIC THEORIES FOR FINITE NUCLEI
BOERSMA, HF; MALFLIET, R
We discuss various relativistic models describing ground-state properties of spherical nuclei. Relativistic mean-field and Hartree-Fock theories, which serve as a starting point for subsequent models, are reviewed. Using a density-dependent parametrization of the Dirac-Brueckner G matrix in nuclear
Interactions of 10.6 GeV/n gold nuclei with light and heavy target nuclei in nuclear emulsion
Energy Technology Data Exchange (ETDEWEB)
Cherry, M.L.; Denes-Jones, P. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy; dabrowska, A. [Institute of Nuclear Physics, Cracow (Poland)] [and others; KLMM
1994-03-01
We have investigated the particle production and fragmentation of nuclei participating in the interactions of 10.6 GeV/n gold nuclei in nuclear emulsions. A new criteria has been developed to distinguish between the interactions of these gold nuclei with the light (H, C, N, O) and heavy (Ag, Br) target nuclei in the emulsion. This has allowed separate analyzes of the multiplicity and pseudo-rapidity distributions of the singly charged particles emitted in Au-(H, C, N, O) and Au-(Ag, Br) interactions, as well as of the models of breakup of the projectile and target nuclei. The pseudo-rapidity distributions show strong forward asymmetries, particularly for the interactions with the light nuclei. Heavy target nuclei produce a more severe breakup of the projectile gold nucleus than do the lighter targets. A negative correlation between the number of fragments emitted from the target nuclei and the degree of centrality of the collisions has been observed, which can be attributed to the total destruction of the relatively light target nuclei by these very heavy projectile nuclei. (author). 14 refs, 11 figs, 1 tab.
Interactions of 10. 6 GeV/n gold nuclei with light and heavy target nuclei in nuclear emulsion
Energy Technology Data Exchange (ETDEWEB)
Cherry, M.L. (Dept. of Physics and Astronomy, Louisiana State Univ., Baton Rouge, LA (United States)); Dabrowska, A. (Inst. of Nuclear Physics, Krakow (Poland)); Deines-Jones, P. (Dept. of Physics and Astronomy, Louisiana State Univ., Baton Rouge, LA (United States)); Dubinina, A.J. (Inst. of Theoretical and Experimental Physics, Moscow (Russian Federation)); Holynski, R. (Inst. of Nuclear Physics, Krakow (Poland)); Jones, W.V. (Dept. of Physics and Astronomy, Louisiana State Univ., Baton Rouge, LA (United States)); Kolganova, E.D. (Inst. of Theoretical and Experimental Physics, Moscow (Russian Federation)); Olszewski, A. (Inst. of Nuclear Physics, Krakow (Poland)); Pozharova, E.A. (Inst. of Theoretical and Experimental Physics, Moscow (Russian Federation)); Sengupta, K. (Dept. of Physics and Astronomy, Louisiana State Univ., Baton Rouge, LA (United States)); Skorodko, T.Yu. (Inst. of Theoretical and Experimental Physics, Moscow (Russian Federation)); Smirnitski, V.A. (Inst.; KLMM Collaboration
1994-09-01
We have investigated the particle production and fragmentation of nuclei participating in the interactions of 10.6 GeV/n gold nuclei in nuclear emulsions. A new criterion has been found to distinguish between the interactions of these gold nuclei with the light (H,C,N,O) and heavy (Ag,Br) target nuclei in the emulsion. This has allowed separate analyses of the multiplicity and pseudo-rapidity distributions of the singly charged particles emitted in Au-(H,C,N,O) and Au-(Ag,Br) interactions, as well as of the modes of breakup of the projectile and target nuclei. The pseudo-rapidity distributions show strong forward asymmetries, particularly for the interactions with the light nuclei. Heavy target nuclei produce a more severe breakup of the projectile gold nucleus than do the lighter targets. A negative correlation between the number of fragments emitted from the target nuclei and the degree of centrality of the collisions has been observed, which can be attributed to the total destruction of the relatively light target nuclei by these very heavy projectile nuclei. (orig.)
Nuclear obscuration in active galactic nuclei
Ramos Almeida, Cristina; Ricci, Claudio
2017-10-01
The material surrounding accreting supermassive black holes connects the active galactic nucleus with its host galaxy and, besides being responsible for feeding the black hole, provides important information on the feedback that nuclear activity produces on the galaxy. In this Review, we summarize our current understanding of the close environment of accreting supermassive black holes obtained from studies of local active galactic nuclei carried out in the infrared and X-ray regimes. The structure of this circumnuclear material is complex, clumpy and dynamic, and its covering factor depends on the accretion properties of the active galactic nucleus. In the infrared, this obscuring material is a transition zone between the broad- and narrow-line regions, and, at least in some galaxies, it consists of two structures: an equatorial disk/torus and a polar component. In the X-ray regime, the obscuration is produced by multiple absorbers across various spatial scales, mostly associated with the torus and the broad-line region. In the coming decade, the new generation of infrared and X-ray facilities will greatly contribute to our understanding of the structure and physical properties of nuclear obscuration in active galactic nuclei.
Experiments with stored relativistic exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Geissel, H.; Radon, T.; Attallah, F. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)] [and others
1998-07-01
Beams of relativistic exotic nuclei were produced, separated and investigated with the combination of the fragment separator FRS and the storage ring ESR. The following experiments are presented: (1) Direct mass measurements of relativistic nickel and bismuth projectile fragments were performed using Schottky spectrometry. Applying electron cooling, the relative velocity spread of the circulating secondary nuclear beams of low intensity was reduced to below 10{sup -6}. The achieved mass resolving power of m/{Delta}m = 6.5 . 10{sup 5} (FWHM) in recent measurements represents an improvement by a factor of two compared to our previous experiments. The previously unknown masses of more than 100 proton-rich isotopes have been measured in the range of 54 {<=} Z {<=} 84. The results are compared with mass models and estimated values based on extrapolations of experimental values. (2) Exotic nuclei with half-lives shorter than the time required for electron cooling can be investigated by time-of-flight measurements with the ESR being operated in the isochronous mode. This novel experimental technique has been successfully applied in a first measurement with nickel fragments. A mass resolving power of m/{Delta}m = 1.5 . 10{sup 5} (FWHM) was achieved in this mode of operation. (3) Nuclear half-lives of stored and cooled bare projectile fragments have been measured to study the influence of the ionic charge state on the beta-decay probability. (orig.)
New spin excitation modes in nuclei
Castel, B.; Zamick, L.
1987-04-01
Recent pion inelastic scattering experiments at LAMPF have revealed the existence of strong spin-flip E1 resonances in the vicinity of the GDR in several light nuclei. We present here a general review of shell model and RPA calculations of S = 0 and S = 1 E1 and E2 strength distributions which offer a broad theoretical context for the discussion of electric spin excitations. We discuss in particular the sensitivity of the spin-flip states to the non-central part of the nuclear interaction. Sum rules techniques are also employed to demonstrate the lack of overlap between S = 0 and S = 1 states. This review suggests that spin excited states respond differently to hadronic, electromagnetic and pionic probes and that the region of up to 10 MeV above the GDR is the most promising for future experimental investigations. Chapter 2 of this review is then devoted to the study of the recently discovered M1 collective (the “scissor” mode) in light nuclei. In particular the study concentrates on model predictions in the f{7}/{2} shell and the subsequent observation of strong M1 excitations in 46Ti performed by Richter's group with the electron accelerator at Darmstadt, as well as inelastic proton scattering performed by an Orsay-Michigan State Collaboration. Rotational model and configuration mixing predictions of the spin and orbital components are also discussed in the context of a comparison between (p,p‧) and (e,e‧) M1 spectra.
Theoretical studies of hadrons and nuclei
Energy Technology Data Exchange (ETDEWEB)
COTANCH, STEPHEN R
2007-03-20
This report details final research results obtained during the 9 year period from June 1, 1997 through July 15, 2006. The research project, entitled Theoretical Studies of Hadrons and Nuclei , was supported by grant DE-FG02-97ER41048 between North Carolina State University [NCSU] and the U. S. Department of Energy [DOE]. In compliance with grant requirements the Principal Investigator [PI], Professor Stephen R. Cotanch, conducted a theoretical research program investigating hadrons and nuclei and devoted to this program 50% of his time during the academic year and 100% of his time in the summer. Highlights of new, significant research results are briefly summarized in the following three sections corresponding to the respective sub-programs of this project (hadron structure, probing hadrons and hadron systems electromagnetically, and many-body studies). Recent progress is also discussed in a recent renewal/supplemental grant proposal submitted to DOE. Finally, full detailed descriptions of completed work can be found in the publications listed at the end of this report.
Dual origin of pairing in nuclei
Energy Technology Data Exchange (ETDEWEB)
Idini, A. [University of Jyvaskyla, Department of Physics (Finland); Potel, G. [Michigan State University, National Superconducting Cyclotron Laboratory (United States); Barranco, F. [Escuela Superior de Ingenieros, Universidad de Sevilla, Departamento de Fìsica Aplicada III (Spain); Vigezzi, E., E-mail: enrico.vigezzi@mi.infn.it [INFN Sezione di Milano (Italy); Broglia, R. A. [Università di Milano, Dipartimento di Fisica (Italy)
2016-11-15
The pairing correlations of the nucleus {sup 120}Sn are calculated by solving the Nambu–Gor’kov equations, including medium polarization effects resulting from the interweaving of quasiparticles, spin and density vibrations, taking into account, within the framework of nuclear field theory (NFT), processes leading to self-energy and vertex corrections and to the induced pairing interaction. From these results one can not only demonstrate the inevitability of the dual origin of pairing in nuclei, but also extract information which can be used at profit to quantitatively disentangle the contributions to the pairing gap Δ arising from the bare and from the induced pairing interaction. The first is the strong {sup 1}S{sub 0} short-range NN potential resulting from meson exchange between nucleons moving in time reversal states within an energy range of hundreds of MeV from the Fermi energy. The second results from the exchange of vibrational modes between nucleons moving within few MeV from the Fermi energy. Short- (v{sub p}{sup bare}) and long-range (v{sub p}{sup ind}) pairing interactions contribute essentially equally to nuclear Cooper pair stability. That is to the breaking of gauge invariance in open-shell superfluid nuclei and thus to the order parameter, namely to the ground state expectation value of the pair creation operator. In other words, to the emergent property of generalized rigidity in gauge space, and associated rotational bands and Cooper pair tunneling between members of these bands.
Spherical nuclei near the stability line and far from it
Energy Technology Data Exchange (ETDEWEB)
Isakov, V. I., E-mail: visakov@thd.pnpi.spb.ru [National Research Centre Kurchatov Institute, Petersburg Nuclear Physics Institute (Russian Federation)
2016-11-15
Results of microscopic and semiphenomenological calculations of features of spherical nuclei lying near the stability line and far from it are presented. The reason why the nuclei being considered are spherical is that they are magic at least in one nucleon sort. The present analysis is performed for Z = 50 and Z = 28 isotopes and for N = 50 isotones, the region extending from neutron-rich to neutron-deficient nuclei being covered. The isotopic dependence of the mean-field spin–orbit nuclear potential is revealed; systematics of energies of levels and probabilities for electromagnetic transitions is examined; and root-mean-square radii of nuclei are calculated, along with the proton- and neutron-density distributions in them. Nuclei in the vicinity of closed shells are considered in detail, and the axial-vector weak coupling constant in nuclei is evaluated. A systematic comparison of the results of calculations with experimental data is performed.
Exotic nuclei and radioactive beams; Noyaux exotiques et faisceaux radioactifs
Energy Technology Data Exchange (ETDEWEB)
Chomaz, P.
1996-12-31
The Nuclei called exotic are all the nuclei that it is necessary to recreate in laboratory to study them. Their life time is too short -in relation to earth age- for it remains enough on earth. The researchers are going to have at their s disposal at GANIL (Caen) with the S.P.I.R.A.L. project, exotic nuclei beams and will study new kinds of nuclear reactions to better understand the atom nucleus. (N.C.). 2 refs., 9 figs.
Investigating the radial distributions of medium-mass nuclei
Energy Technology Data Exchange (ETDEWEB)
Benlliure, J.; Dragosavac, D.; Perez-Loureiro, D.; Alvarez-Pol, H. [Universidad de Santiago de Compostela, 15782 Santiago de Compostela Spain (Spain); Blank, B. [Centre d' Etudes Nucleaires Bordeaux-Gradignan, F-33175 Gradignan (France); Casarejos, E. [Universidad de Santiago de Compostela, 15782 Santiago de Compostela Spain (Spain); Fohr, V. [Gesellschaft fuer Schwerionenforschung mbH, D-64291 Darmstadt (Germany); Gascon, M. [Universidad de Santiago de Compostela, 15782 Santiago de Compostela Spain (Spain); Gawlikowicz, W. [Heavy Ion Laboratory, University of Warsaw, PL-02-093 (Poland); Heinz, A. [WNSL, Yale University, New Haven, Connecticut 06511 (United States); Helariutta, K. [Laboratory of Radiochemistry, P. O. Box 55, FI-00014 Helsinki (Finland); Lukic, S.; Montes, F. [Gesellschaft fuer Schwerionenforschung mbH, D-64291 Darmstadt (Germany); Pienkowski, L. [Heavy Ion Laboratory, University of Warsaw, PL-02-093 (Poland); Staniou, M. [Gesellschaft fuer Schwerionenforschung mbH, D-64291 Darmstadt (Germany); Subotic, K. [Institute of Nuclear Sciences, VINCA, Belgrade 11001 (Serbia); Suemmerer, K. [Gesellschaft fuer Schwerionenforschung mbH, D-64291 Darmstadt (Germany); Taieb, J. [CEA/DAM, Bruyeres-le-Chatel, 91290 Aapajon Cedex (France); Trzcinska, A. [Heavy Ion Laboratory, University of Warsaw, PL-02-093 (Poland); Veselsky, M. [Slovak Academy of Sciences, Dubravska cesta 9, Bratislava (Slovakia)
2010-03-01
The radial evolution of the matter distributions with neutron excess has been investigated at GSI measuring total interaction cross sections for long isotopic chains of medium-mass nuclei. Comparisons with different model calculations show a clear increase of the total interaction cross sections for the most neutron-rich nuclei that we interpret as a signature for a larger matter radius of those nuclei.
Energy Technology Data Exchange (ETDEWEB)
Muecher, Dennis
2009-04-28
Within this thesis the influence of subshell closures at neutron numbers N=40 and N=56 upon nuclear structure was examined. The work was focussed on the nucleus {sup 70}Zn that has been studied by a series of experiments. Firstly a photon-scattering experiment was performed at the University of Stuttgart in order to revise the lifetime of the 2{sup +}{sub 2} state in {sup 70}Zn. Furthermore {sup 70}Zn was measured using monoenergetic neutrons at the University of Kentucky yielding many decisive corrections to the low-energy level scheme. In addition, magnetic moments of shortlived states were investigated with the method of transient magnetic fields. As a consequnce of these results it was shown that the nucleus {sup 70}Zn can be described within the F spin symmetric dynamical symmetry U(5) of the IBM-2. A new interpretation was given for the inconvenient behavior of the 0{sup +}{sub 2} and 2{sup +}{sub 3} level. The 2{sup +}{sub 3} state was proposed as the mixedsymmetry state 2{sup +}{sub 1,ms}. Furthermore candidates for the mixed-symmetry states of higher phonon order were presented. It was shown that strong mixing of the involved states occurs. The exceptional behavior of the 2{sup +}{sub 1,ms} states in the even-even zinc isotopes was interpreted as a breaking of the F spin symmetry at the transition to an isospin symmetric system. Experiments with radioactive beams of the nuclei {sup 88}Kr and {sup 92}Kr were presented as well. This was done to show how far mixed symmetry states can be studied using radioactive ion beam experiments in the future. (orig.)
Do nucleons in abnormal-parity states contribute to deformation
Energy Technology Data Exchange (ETDEWEB)
Bhatt, K.H. (Department of Physics and Astronomy, University of Mississippi, University, Mississippi 38677 (United States) Joint Institute for Heavy-Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, Tennessee 37831 (United States)); Nestor, C.W. Jr.; Raman, S. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States))
1992-07-01
We consider intrinsic states of highly deformed nuclei in the framework of the universal Woods-Saxon model and show that valence nucleons in abnormal-parity high-{ital j} states contribute {similar to}20% to the electric quadrupole moments of these nuclei. Similarly, we show that in the single-shell asymptotic Nilsson model this contribution is {similar to}25% if reasonable effective charges are employed. We discuss, at some length, procedures used to arrive at reasonable effective charges. Both models reproduce the measured {ital B}({ital E}2;0{sub 1}{sup +}{r arrow}2{sub 1}{sup +}) values in the rare-earth and actinide regions without the need for normalization constants. No support is found for the assumption made in the pseudo-SU(3) and the fermion dynamic symmetry models that valence nucleons in abnormal-parity high-{ital j} states do not contribute to deformation. This counterintuitive assumption leads to an underestimate of the {ital B}({ital E}2;0{sub 1}{sup +}{r arrow}2{sub 1}{sup +}) values, which is compensated in these models by the use of appropriate normalization constants. Once the magnitudes are fixed, both models do correctly reproduce the {ital B}({ital E}2) trends.
Observation of inception of sheet cavitation from free nuclei
Tsuru, Wakana; Konishi, Takafumi; Watanabe, Satoshi; Tsuda, Shin-ichi
2017-06-01
Prediction of inception of sheet cavitation on solid walls has been recognized to be very difficult, since it is significantly affected by the boundary layer flow characteristics, the population of free nuclei, the nuclei held in the wall roughness, the amount of dissolved air in liquid and so on. It has not sufficiently been made clear how the inception is affected by the conditions of water qualities and background flow characteristics. In this study, high speed observation of inception of sheet cavity from free nuclei is conducted for a two-dimensional convergent- divergent nozzle flow, where the sheet cavity forms just downstream of the nozzle throat. The effects of the amount of dissolved air and the free stream velocity on the inception process of sheet cavitation is examined. In addition, the bubble nuclei density, which is well known to be important factor for cavitation inception, is passively controlled by the filter installed in the tunnel. From the observations, it is confirmed that the nuclei number density significantly affects the formation of sheet cavity rather than the other two parameters. In conditions with large nuclei number density, the sheet cavity does not form, and bubbly cavitation appears instead. In the case with small nuclei number density, the sheet cavity forms from a single flowing nucleus and develops streamwisely and spanwisely. In the conditions with medium nuclei number density, the sheet cavity also forms but is shorter/ narrower streamwisely/spanwisely, due to interaction of other nuclei flowing near the formed sheet cavity.
Search for η' Mesic Nuclei in GSI/FAIR
Itahashi, K.; Ayyad, Y.; Benlliure, J.; Brinkmann, K.-T.; Friedrich, S.; Fujioka, H.; Geissel, H.; Gellanki, J.; Guo, C.; Gutz, E.; Haettner, E.; Harakeh, M. N.; Hayano, R. S.; Higashi, Y.; Hirenzaki, S.; Hornung, C.; Igarashi, Y.; Ikeno, N.; Iwasaki, M.; Jido, D.; Kalantar-Nayestanaki, N.; Kanungo, R.; Knoebel, R.; Kurz, N.; Metag, V.; Mukha, I.; Nagae, T.; Nagahiro, H.; Nanova, M.; Nishi, T.; Ong, H. J.; Pietri, S.; Prochazka, A.; Rappold, C.; Reiter, M. P.; Rodríguez-Sánchez, J. L.; Scheidenberger, C.; Simon, H.; Sitar, B.; Strmen, P.; Sun, B.; Suzuki, K.; Szarka, I.; Takechi, M.; Tanaka, Y. K.; Tanihata, I.; Terashima, S.; Watanabe, Y. N.; Weick, H.; Widmann, E.; Winfield, J. S.; Xu, X.; Yamakami, H.; Zhao, J.
Origin of an exceptionally large mass of an η' meson has been attracting many theoretical and experimental studies. A large mass reduction was predicted for η' mesons accommodated in a nuclear medium, which leads to possible existence of η'-mesic nuclei, η' mesons bound to nuclei. We conducted a direct experimental search for the η'-mesic nuclei in GSI by measuring excitation spectra of 11C nuclei near the η' emission threshold. The present status of the experimental data analysis and future perspectives are discussed.
On the pairing effects in triaxial nuclei
Energy Technology Data Exchange (ETDEWEB)
Oudih, M. R. [Laboratoire de Physique Théorique, Faculté de Physique,USTHB BP 32, El Alia, 16111 Bab Ezzouar, Algiers (Algeria); Fellah, M.; Allal, N. H. [Centre de Recherche Nucléaire d' Alger, 2 Bd. Frantz Fanon, BP. 399 Alger-Gare, Algiers, Algeria and Laboratoire de Physique Théorique, Faculté de Physique,USTHB BP 32, El Alia, 16111 Bab Ezzouar, Algiers (Algeria)
2014-03-05
Triaxial deformation effect on the pairing correlations is studied in the framework of the Skyrme Hartree-Fock-Bogoliubov theory. Quantities such as binding energy, gap parameter and particle-number fluctuation are considered in neutron-rich Mo isotopes. The results are compared with those of axially symmetric calculation and with available experimental data. The role played by the particle-number projection is outlined.
Structure study of two-neutron halo nuclei, 22C using three-body model
Salih, Fitri Hakeem M.; Radiman, Shahidan; Siong, Khoo Kok
2017-01-01
Nucleus 22C is one of the exotic neutron-rich nuclei placed near neutron drip line has a Borromean system (core + n + n). The weakly bound system causes nucleus 22C has large radial extended. The structure of two-neutron halo 22C was investigated in the three-body model (20C+ n +n). Jacobi coordinates was used in this model and used to describe configuration-T and Y. Hamiltonian of three-body system was used to study neutron halo features such as binding energy of neutron valence, root mean square matter radii, and core deformation. In this study, the core deformation was used to determine the binding energy of neutron valence and root mean square matter radii. All the calculations were run in the MATLAB. The results showed that the 22C binding energies of neutron valence were in between -1.737 -1.792 MeV, while the root mean squares matter radii were in between 6.451 7.011 fm, and the core of 22C has deformation values. Based on the results, 22C is considered as a halo nucleus due to the root mean square matter radii is bigger than 20C.
Effect of triaxial deformations on the splitting of the M1 isovector rotational state
Energy Technology Data Exchange (ETDEWEB)
Lo Iudice, N.; Lipparini, E.; Stringari, S.; Palumbo, F.; Richter, A.
1985-10-24
A sum rule approach is proposed for investigating the effects of triaxially on the splitting of the M1 isovector rotational state. The explicit dependence of the energy and M1 strength of these states on the deformation parameters US and el is derived. It is shown that the splitting recently found in WUDy and XUYb might be explained by assuming that these nuclei deviate slightly from axial symmetry. (orig.).
Formation and subdivision of deformation structures during plastic deformation
DEFF Research Database (Denmark)
Jakobsen, B.; Poulsen, H.F.; Lienert, U.
2006-01-01
During plastic deformation of metals and alloys, dislocations arrange in ordered patterns. How and when these self-organization processes take place have remained elusive, because in situ observations have not been feasible. We present an x-ray diffraction method that provided data on the dynamics...... of individual, deeply embedded dislocation structures. During tensile deformation of pure copper, dislocation-free regions were identified. They showed an unexpected intermittent dynamics, for example, appearing and disappearing with proceeding deformation and even displaying transient splitting behavior....... Insight into these processes is relevant for an understanding of the strength and work-hardening of deformed materials....
Impact of spin-orbit density dependent potential in heavy ion reactions forming Se nuclei
Energy Technology Data Exchange (ETDEWEB)
Rajni; Sharma, Ishita; Sharma, Manoj K. [Thapar University, School of Physics and Materials Science, Patiala (India); Jain, Deepika [Mata Gujri College, Department of Physics, Fatehgarh Sahib (India)
2017-10-15
The Skyrme energy density formalism is employed to explore the effect of spin-orbit interaction potential by considering a two nucleon transfer process via various entrance channels such as {sup 23}Na + {sup 49}V, {sup 25}Mg + {sup 47}Ti, {sup 27}Al + {sup 45}Sc, {sup 29}Si + {sup 43}Ca and {sup 31}P + {sup 41}K, all forming the same compound system {sup 72}Se*, using both spherical as well as quadrupole deformed (β{sub 2}) nuclei. For spherical nuclei, the spin-orbit density part V{sub J} of nuclear potential remains unaffected with the transfer of two nucleons from the target to the projectile, however, show notable variation in magnitude after inclusion of deformation effects. Likewise, deformations play an important role in the spin-orbit density independent part V{sub P}, as the fusion pocket start appears, which otherwise diminish for the spherical nuclei. Further, the effect of an increase in the N/Z ratio of Se is explored on V{sub J} as well as V{sub P} and results are compared with transfer channels. In addition to this, the role of double spin-orbit parameters (W{sub 0} and W{sub 0}{sup '}) with relative contribution of the isoscalar and isovector parts of spin-orbit strength is explored in view of SkI2, SkI3 and SkI4 Skyrme forces. Beside this, the decay path of {sup 72}Se* nucleus formed in {sup 27}Al + {sup 45}Sc reaction is investigated within the framework of dynamical cluster decay model (DCM), where the nuclear proximity potential is obtained by both Skyrme energy density formalism (SEDF) and proximity pocket formula. The fusion hindrance in the {sup 27}Al + {sup 45}Sc reaction is also addressed via the barrier lowering parameter ΔV{sub B}. Finally, the contribution of spin-orbit density dependent interaction potential is estimated for the {sup 27}Al + {sup 45}Sc reaction using single (W{sub 0} or W{sub 0}{sup '}) and double spin-orbit parameters (W{sub 0} and W{sub 0}{sup '}). (orig.)
Are cometary nuclei primordial rubble piles?
Weissman, P. R.
1986-01-01
Whipple's icy conglomerate model for the cometary nucleus has had considerable sucess in explaining a variety of cometary phenomena such as gas production rates and nongravitational forces. However, as discussed here, both observational evidence and theoretical considerations suggest that the cometary nucleus may not be a well-consolidated single body, but may instead be a loosely bound agglomeration of smaller fragments, weakly bonded and subject to occasional or even frequent disruptive events. The proposed model is analogous to the 'rubble pile' model suggested for the larger main-belt asteroids, although the larger cometary fragments are expected to be primordial condensations rather than collisionally derived debris as in the asteroid case. The concept of cometary nuclei as primordial rubble piles is proposed as a modification of the basic Whipple model, not as a replacement for it.
Quarks and gluons in hadrons and nuclei
Energy Technology Data Exchange (ETDEWEB)
Close, F.E. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA))
1989-12-01
These lectures discuss the particle-nuclear interface -- a general introduction to the ideas and application of colored quarks in nuclear physics, color, the Pauli principle, and spin flavor correlations -- this lecture shows how the magnetic moments of hadrons relate to the underlying color degree of freedom, and the proton's spin -- a quark model perspective. This lecture reviews recent excitement which has led some to claim that in deep inelastic polarized lepton scattering very little of the spin of a polarized proton is due to its quarks. This lecture discusses the distribution functions of quarks and gluons in nucleons and nuclei, and how knowledge of these is necessary before some quark-gluon plasma searches can be analyzed. 56 refs., 2 figs.
Spectroscopy of Exotic Nuclei via Proton Removal
Bazin, Daniel
2017-09-01
Inverse kinematics proton removal reactions using light targets are now well established as a powerful tool for spectroscopy of neutron-rich nuclei. The peripheral nature of these so-called knockout reactions enables the use of simple eikonal models to calculate single-particle cross sections and deduce spectroscopic factors. Exclusive experiments have shown these models to predict the relative proportions of the different components of the cross sections very accurately. However, these models have limitations such as the absence of core excitations for instance, and benchmarking the deduction of spectroscopic factors remains a challenging task. In particular, differences with respect to other reactions tools such as transfer reactions or quasi-free proton and electron scattering, are still unexplained. This talk will concentrate on establishing the current status of knockout reaction mechanism studies and benchmarking efforts.
The resonance neutron fission on heavy nuclei
Kopach, Yu N; Furman, V I; Alfimenkov, V P; Lason', L; Pikelner, L B; Gonin, N N; Kozlovskij, L K; Tambovtsev, D I; Gagarskij, A M; Petrov, G A; Sokolov, V E
2001-01-01
A new approach to the description of the fission, similar to the well-known reaction theory and based on the helicity representation for the exit fission channels, is briefly summarized. This approach allows one to connect the multimodal fission representation with A. Bohr's concept of the fission transition states and to obtain formulae for the partial and differential fission cross sections. The formulae are used for analysis of the angular anisotropy of fragments in the neutron resonance induced fission of aligned sup 2 sup 3 sup 5 U nuclei and of the P-even angular forward-backward and right-left correlations of fragments oe the P-odd correlations caused by the interference of s- and p-wave neutron resonances
Shell model calculations for exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Brown, B.A. (Michigan State Univ., East Lansing, MI (USA)); Warburton, E.K. (Brookhaven National Lab., Upton, NY (USA)); Wildenthal, B.H. (New Mexico Univ., Albuquerque, NM (USA). Dept. of Physics and Astronomy)
1990-02-01
In this paper we review the progress of the shell-model approach to understanding the properties of light exotic nuclei (A < 40). By shell-model'' we mean the consistent and large-scale application of the classic methods discussed, for example, in the book of de-Shalit and Talmi. Modern calculations incorporate as many of the important configurations as possible and make use of realistic effective interactions for the valence nucleons. Properties such as the nuclear densities depend on the mean-field potential, which is usually separately from the valence interaction. We will discuss results for radii which are based on a standard Hartree-Fock approach with Skyrme-type interactions.
Galactic Nuclei through the ``Lens" of HST
Faber, S. M.
1993-12-01
HST has now imaged upwards of 50 galactic nuclei. The sample divides into two broad categories: early-type bulges/ellipticals, and spirals. Early-type nuclei tend to follow broad trends foreshadowed by earlier ground-based data, but with some important differences. Large early-type galaxies show ``break radii" that are analogous to classical core radii. However, inside these cores, most light profiles do not level out but continue to increase in shallow power laws inwards to the resolution limit (0.1\\arcsec). We call such nuclei ``soft cores." Small early-type galaxies are completely unresolved and show steep power-laws at all radii. We call these ``hard cores." Early-type galaxies of intermediate brightness seem to be divided into hard cores or soft cores according to rotation and isophote shape: rotating, disky E's have hard, steep cores, while non-rotating, boxy E's have soft cores and breaks. Thus, core properties seem to reinforce the division of ellipticals into two fundamentally different families that has been emerging for some time now based on other data. Core phase-space density shows an enormous range in early-type galaxies, decreasing by a factor of 100 million from the smallest ellipticals to the largest. Since phase-space density is believed to either remain constant or increase during mergers, this trend casts doubt on whether large E's could have formed by merging from progenitors that looked like present-day small E's. The smallest and closest elliptical, M32, is so dense that stellar collisions have likely been important over the age of the Universe. M32's relatively high stellar velocity dispersion ( ~ 100 km s(-1) ) favors runaway merging in collisions to form a black hole. Evidence for such a BH has been found from ground-based spectroscopy. Compared to early-type galaxies, spiral nuclei show a wider range of morphologies and physical phenomena, some quite exotic. Nuclear star clusters are common in spirals. The density is so high in the
Rotary deformity in degenerative spondylolisthesis
Energy Technology Data Exchange (ETDEWEB)
Kang, Sung Gwon; Kim, Jeong; Kho, Hyen Sim; Yun, Sung Su; Oh, Jae Hee; Byen, Ju Nam; Kim, Young Chul [Chosun University College of Medicine, Gwangju (Korea, Republic of)
1994-05-15
We studied to determine whether the degenerative spondylolisthesis has rotary deformity in addition to forward displacement. We have made analysis of difference of rotary deformity between the 31 study groups of symptomatic degenerative spondylolisthesis and 31 control groups without any symptom, statistically. We also reviewed CT findings in 15 study groups. The mean rotary deformity in study groups was 6.1 degree(the standard deviation is 5.20), and the mean rotary deformity in control groups was 2.52 degree(the standard deviation is 2.16)(p < 0.01). The rotary deformity can be accompanied with degenerative spondylolisthesis. We may consider the rotary deformity as a cause of symptomatic degenerative spondylolisthesis in case that any other cause is not detected.
Nuclear moments and deformation changes in the lightest Pt isotopes measured by laser spectroscopy
Roussière, B; Crawford, J; Duong, H T; Genevey, J; Girod, M; Huber, G; Ibrahim, F; Krieg, M; Le Blanc, F; Lee, J K P; Obert, J; Oms, J; Peru, S; Pinard, J; Putaux, J C; Sauvage, J; Sebastian, V; Zemlyanoi, S G; Forkel-Wirth, Doris; Lettry, Jacques
1999-01-01
Laser spectroscopy measurements are performed with the lightest neutron-deficient platinum isotopes using the experimental setup COMPLIS installed at the ISOLDE-Booster facility. The hyperfine spectra of /sup 182-178/Pt and /sup 183m/Pt are recorded for the first time from the optical transition 5d/sup 9/6s/sup 3/D/sub 3/ to 5d/sup 9/6p/sup 3/P/sub 2/. The variation in the mean-square charge radius of these nuclei and the magnetic and quadrupole (for I>or=1) moments of the odd isotope nuclei are found. A large deformation change between the /sup 183g/Pt and /sup 183m/Pt nuclei, quite large inverted odd-even staggering of the charge radius around the neutron midshell N=104, and a nuclear deformation drop in the region A=179 are revealed. All the results are discussed in terms of nuclear shape variation and are compared with the results of Hartree-Fock- Bogoliubov calculations involving the Gogny force. Comparison of the deformation measured from /sup 183g, m/Pt to the odd-odd isotone /sup 184g, m/Au shows that...
Man'ko, V I
1993-01-01
Brownian motion may be embedded in the Fock space of bosonic free field in one dimension.Extending this correspondence to a family of creation and annihilation operators satisfying a q-deformed algebra, the notion of q-deformation is carried from the algebra to the domain of stochastic processes.The properties of q-deformed Brownian motion, in particular its non-Gaussian nature and cumulant structure,are established.
Energy Technology Data Exchange (ETDEWEB)
Zweidinger, Markus
2016-06-22
In the present work the dipole strength distribution in the stable even-even isotopes {sup 92}Zr and {sup 94}Zr is investigated. To excite the nuclei from the ground state to an excited state, real photons are used. This method is called Nuclear Resonance Fluorescence. The measurements were performed at two different setups. The first one is the Darmstadt High Intensity Photon Setup (DHIPS). At DHIPS the measurements yield information about the spin quantum number and the integrated cross section. The second part of the experiments took place at the High Intensity γ-ray Source (HIγS). Here, information about the parity quantum number and the averaged branching ratio of the excited state is accessible. In total, 105 dipole excited states in the nucleus {sup 92}Zr and 124 in the isotope {sup 94}Zr are observed, most of them for the first time. The extracted dipole strength distribution is investigated for the existence of the pygmy dipole resonance that was observed in neighboring nuclei. Furthermore, in previously performed experiments on the isotope {sup 90}Zr, the spin-flip M1 resonance was observed as well. Therefore, also the magnetic dipole strength is investigated. Further, by comparison with global systematics, the two-phonon state is identified. Additionally, the averaged branching ratio is compared to the results of theoretical calculations in the framework of the statistical model.
Decay of Hot Nuclei at Low Spins Produced by Antiproton-Annihilation in Heavy Nuclei
2002-01-01
% PS208 \\\\ \\\\ The objective of the experiment is to study (i) the thermal excitation energy distribution of antiproton-induced reactions in heavy nuclei and (ii) the decay properties of hot nuclei at low spins via evaporation, multifragmentation and fission as a function of excitation energy. The experimental set-up consists of 4-$\\pi$ detectors: the Berlin Neutron Ball~(BNB) which is a spherical shell of gadolinium-loaded scintillator liquid with an inner and outer diameter of 40 and 160~cm, respectively. This detector counts the number of evaporated neutrons in each reaction. Inside BNB there is a 4-$\\pi$ silicon ball~(BSIB) with a diameter of 20~cm consisting of 162 detectors which measure energy and multiplicity of all emitted charged nuclear particles. The particles are identified via time of flight, energy and pulse shape correlations.
Plastic Deformation of Metal Surfaces
DEFF Research Database (Denmark)
Hansen, Niels; Zhang, Xiaodan; Huang, Xiaoxu
2013-01-01
parameters by TEM and EBSD and apply strength-structural relationships established for the bulk metal deformed to high strains. This technique has been applied to steel deformed by high energy shot peening and a calculated stress gradient at or near the surface has been successfully validated by hardness......Plastic deformation of metal surfaces by sliding and abrasion between moving parts can be detrimental. However, when the plastic deformation is controlled for example by applying different peening techniques hard surfaces can be produced which can increase the fracture resistance and fatigue life...
Angular Limb Deformities: Growth Retardation.
McCarrel, Taralyn M
2017-08-01
Angular limb deformities are common in foals; however, the importance of the deformity and if treatment is required depend on the degree of deformity relative to normal conformation for stage of growth, the breed and discipline expectations, age, and response to conservative therapies. This article addresses the importance of the foal conformation examination to determine which foals need surgical intervention to correct an angular deformity and when. Techniques for surgical growth retardation include the transphyseal staple, screw and wire transphyseal bridge, and transphyseal screw. Appropriate timing for intervention for each location and complications associated with each procedure are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.
Deformable paper origami optoelectronic devices
He, Jr-Hau
2017-01-19
Deformable optoelectronic devices are provided, including photodetectors, photodiodes, and photovoltaic cells. The devices can be made on a variety of paper substrates, and can include a plurality of fold segments in the paper substrate creating a deformable pattern. Thin electrode layers and semiconductor nanowire layers can be attached to the substrate, creating the optoelectronic device. The devices can be highly deformable, e.g. capable of undergoing strains of 500% or more, bending angles of 25° or more, and/or twist angles of 270° or more. Methods of making the deformable optoelectronic devices and methods of using, e.g. as a photodetector, are also provided.
4th International Conference on Exotic Nuclei and Atomic Masses
Gross, Carl J; Rykaczewski, Krzysztof P; The European Physical Journal A : Volume 25, Supplement 1, 2005
2005-01-01
The International Conference on Exotic Nuclei and Atomic Masses (ENAM) has gained the status of the premier meeting for the physics of nuclei far from stability. The selected and refereed papers presenting the main results constitute valuable proceedings that offer everyone working in this field an authoritative and comprehensive source of reference.
Kaonic nuclei excited by the (K{sup -}, N) reaction
Energy Technology Data Exchange (ETDEWEB)
Kishimoto, Tadafumi [Dept. of Phys., Osaka Univ., Toyonaka, Osaka (Japan)
2000-01-01
We show that kaonic nuclei can be produced by the (K{sup -}, p) and (K{sup -}, n) reactions. The reactions are shown to have cross sections experimentally measurable. The observation of the kaonic nuclei gives a kaon-nucleus potential which answers the question on the existence of kaon condensation in dense nuclear matter especially neutron stars. (author)
Spectroscopic factors for two-proton radioactive nuclei
Indian Academy of Sciences (India)
Spectroscopic factors for two-proton emitting nuclei are discussed in the framework of the BCS (Bardeen–Cooper–Schriefer) model. Calculations carried out for the two-proton unstable 45Fe, 48Ni and 54Zn nuclei are presented. Author Affiliations. Chinmay Basu1. Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, ...
Two Topics in the Physics of Light Nuclei
Energy Technology Data Exchange (ETDEWEB)
Rocco Schiavilla
2007-09-10
I review how tensor forces affect the ground-state structure of nuclei, and how isospin-symmetry-breaking corrections at the nucleon and nuclear level contaminate the asymmetry measured in parity-violating electron scattering from nuclei, complicating the extraction of the strange-quark form factors from these measurements.
Nuclear morphology and deformation in engineered cardiac myocytes and tissues.
Bray, Mark-Anthony P; Adams, William J; Geisse, Nicholas A; Feinberg, Adam W; Sheehy, Sean P; Parker, Kevin K
2010-07-01
Cardiac tissue engineering requires finely-tuned manipulation of the extracellular matrix (ECM) microenvironment to optimize internal myocardial organization. The myocyte nucleus is mechanically connected to the cell membrane via cytoskeletal elements, making it a target for the cellular response to perturbation of the ECM. However, the role of ECM spatial configuration and myocyte shape on nuclear location and morphology is unknown. In this study, printed ECM proteins were used to configure the geometry of cultured neonatal rat ventricular myocytes. Engineered one- and two-dimensional tissue constructs and single myocyte islands were assayed using live fluorescence imaging to examine nuclear position, morphology and motion as a function of the imposed ECM geometry during diastolic relaxation and systolic contraction. Image analysis showed that anisotropic tissue constructs cultured on microfabricated ECM lines possessed a high degree of nuclear alignment similar to that found in vivo; nuclei in isotropic tissues were polymorphic in shape with an apparently random orientation. Nuclear eccentricity was also increased for the anisotropic tissues, suggesting that intracellular forces deform the nucleus as the cell is spatially confined. During systole, nuclei experienced increasing spatial confinement in magnitude and direction of displacement as tissue anisotropy increased, yielding anisotropic deformation. Thus, the nature of nuclear displacement and deformation during systole appears to rely on a combination of the passive myofibril spatial organization and the active stress fields induced by contraction. Such findings have implications in understanding the genomic consequences and functional response of cardiac myocytes to their ECM surroundings under conditions of disease. Copyright 2010 Elsevier Ltd. All rights reserved.
A new spin-oriented nuclei facility: POLAREX
Directory of Open Access Journals (Sweden)
Etilé A.
2014-03-01
Full Text Available Using the On-Line Nuclear Orientation method, POLAREX (POLARization of EXotic nuclei is a new facility allowing to study the anisotropic decay of spin-oriented nuclei. Based on the combination of on-line implantation of radioactive nuclei with Low Temperature Nuclear Orientation technique and Nuclear Magnetic Resonance, POLAREX allows to measure nuclear electromagnetic moments and ground-state spins, in the aim to get information about the wave function composition of the nuclear state. Polarized nuclei can also be used to study fundamental interactions involving nuclear β-decay asymmetries. The POLAREX infrastructure will be installed at Accélérateur Linéaire auprés du Tandem d’Orsay in order to study neutron-rich nuclei, some of which have not been studied yet. Will be presented here, all the possibilities of this new facility and a non exhaustive scientific program.
Elevated temperature deformation analysis
Nelson, J. M.
The paper demonstrates a novel nondestructive test and data analysis technique for quantitative measurement of circumferentially varying flexural moduli of 2D involute carbon-carbon tag rings containing localized wrinkles and dry plies at room and rocket nozzle operating temperatures. Room temperature computed tomography (CT) deformation tests were performed on 11 carbon-carbon rings selected from the cylinders and cones fabricated under the NDE data application program and two plexiglass rings fabricated under this program. This testing and analysis technique is found to have primary application in validation of analytical models for carbon-carbon performance modeling. Both effects of defects assumptions, the effects of high temperature environments, and failure-related models can be validated effectively. The testing and analysis process can be interwoven in a manner that increases the engineering understanding of the material behavior and permits rapid resolution of analysis questions. Specific recommendations for the development and implementation of this technique are provided.
Marginal deformations & rotating horizons
Anninos, Dionysios; Anous, Tarek; D'Agnolo, Raffaele Tito
2017-12-01
Motivated by the near-horizon geometry of four-dimensional extremal black holes, we study a disordered quantum mechanical system invariant under a global SU(2) symmetry. As in the Sachdev-Ye-Kitaev model, this system exhibits an approximate SL(2, ℝ) symmetry at low energies, but also allows for a continuous family of SU(2) breaking marginal deformations. Beyond a certain critical value for the marginal coupling, the model exhibits a quantum phase transition from the gapless phase to a gapped one and we calculate the critical exponents of this transition. We also show that charged, rotating extremal black holes exhibit a transition when the angular velocity of the horizon is tuned to a certain critical value. Where possible we draw parallels between the disordered quantum mechanics and charged, rotating black holes.
Comparison with Tilted Axis Cranking and particle rotor model for triaxial nuclei
Energy Technology Data Exchange (ETDEWEB)
Ohtsubo, Shin-ichi; Shimizu, Yoshifumi R. [Kyushu Univ., Fukuoka (Japan). Dept. of Physics
1998-03-01
An extension of the cranking model in such a way to allow a rotation axis to deviate from the principal axes of the deformed mean-field is a promising tool for the spectroscopic study of rapidly rotating nuclei. We have applied such a `Tilted Axis Cranking` (TAC) method to a simple system of one-quasiparticle coupled to a triaxial rotor and compared it with a particle-rotor coupling calculation in order to check whether the spin-orientation degrees of freedom can be well described within the mean-field approximation. The result shows that the TAC method gives a good approximation to observable quantities and it is a suitable method to understand the dynamical interplay between the collective and single-particle angular momenta. (author)
Shell energy in the heaviest nuclei using the Green's function oscillator expansion method
Energy Technology Data Exchange (ETDEWEB)
Cwiok, S.; Dudek, W.; Kaszynski, P. [Warsaw University of Technology, Institute of Physics, Warsaw (Poland); Nazarewicz, W. [University of Tennessee, Department of Physics and Astronomy, Knoxville, TN (United States); Oak Ridge National Laboratory, Physics Division, P.O. Box 2008, Oak Ridge, TN (United States); Warsaw University, Institute of Theoretical Physics, Warsaw (Poland)
2005-03-01
The Green's function oscillator expansion method and the generalized Strutinsky smoothing procedure are applied to shell corrections in the heaviest elements. A macroscopic-microscopic method with a finite deformed Woods-Saxon potential is used. The stability condition for the shell correction is discussed in detail and the parameters defining the smoothing procedure are carefully determined. It is demonstrated that the spurious contribution to the total binding energy due to the unphysical particle gas that appears in the standard method can be as large as 1.5 MeV for weakly bound neutron-rich superheavy nuclei, but the effect on energy differences (e.g., alpha-decay values) is fairly small. (orig.)
Excited collective states of nuclei within Bohr Hamiltonian with Tietz-Hua potential
Energy Technology Data Exchange (ETDEWEB)
Chabab, M.; El Batoul, A.; Lahbas, A.; Oulne, M. [Cadi Ayyad University, High Energy Physics and Astrophysics Laboratory, Faculty of Sciences Semlalia, Marrakesh (Morocco); Hamzavi, M. [University of Zanjan, Department of Physics, Zanjan (Iran, Islamic Republic of)
2017-07-15
In this paper, we present new analytical solutions of the Bohr Hamiltonian problem that we derived with the Tietz-Hua potential, here used for describing the β-part of the nuclear collective potential plus that of the harmonic oscillator for the γ-part. Also, we proceed to a systematic comparison of the numerical results obtained with this kind of β-potential with others which are widely used in such a framework as well as with the experiment. The calculations are carried out for energy spectra and electromagnetic transition probabilities for γ-unstable and axially symmetric deformed nuclei. In the same frame, we show the effect of the shape flatness of the β-potential beyond its minimum on transition rates calculations. (orig.)
Mid-infrared spectra of comet nuclei
Kelley, Michael S. P.; Woodward, Charles E.; Gehrz, Robert D.; Reach, William T.; Harker, David E.
2017-03-01
Comet nuclei and D-type asteroids have several similarities at optical and near-IR wavelengths, including near-featureless red reflectance spectra, and low albedos. Mineral identifications based on these characteristics are fraught with degeneracies, although some general trends can be identified. In contrast, spectral emissivity features in the mid-infrared provide important compositional information that might not otherwise be achievable. Jovian Trojan D-type asteroids have emissivity features strikingly similar to comet comae, suggesting that they have the same compositions and that the surfaces of the Trojans are highly porous. However, a direct comparison between a comet and asteroid surface has not been possible due to the paucity of spectra of comet nuclei at mid-infrared wavelengths. We present 5-35 μm thermal emission spectra of comets 10P/Tempel 2, and 49P/Arend-Rigaux observed with the Infrared Spectrograph on the Spitzer Space Telescope. Our analysis reveals no evidence for a coma or tail at the time of observation, suggesting the spectra are dominated by the comet nucleus. We fit each spectrum with the near-Earth asteroid thermal model (NEATM) and find sizes in agreement with previous values. However, the NEATM beaming parameters of the nuclei, 0.74-0.83, are systematically lower than the Jupiter-family comet population mean of 1.03 ± 0.11, derived from 16- and 22-μm photometry. We suggest this may be either an artifact of the spectral reduction, or the consequence of an emissivity low near 16 μm. When the spectra are normalized by the NEATM model, a weak 10-μm silicate plateau is evident, with a shape similar to those seen in mid-infrared spectra of D-type asteroids. A silicate plateau is also evident in previously published Spitzer spectra of the nucleus of comet 9P/Tempel 1. We compare, in detail, these comet nucleus emission features to those seen in spectra of the Jovian Trojan D-types (624) Hektor, (911) Agamemnon, and (1172) Aneas, as well
Could life have evolved in cometary nuclei?
Bar-Nun, A.; Lazcano-Araujo, A.; Oró, J.
1981-12-01
Hoyle and Wickramasinghe have recently suggested that life may have originated in cometary nuclei rather than directly on Earth. Even though comets are known to contain substantial amounts of organic compounds which may have contributed to the formation of biochemical molecules on the primitive Earth, it is doubtful that the process of chemical evolution has proceeded in comets beyond the stage that has occurred in carbonaceous chondrites. Some of the arguments which do not favor the occurrence of biopoesis in comets are: 1. A large layer of cometary ices is ablated from the nucleus' surface each time the comet passes through perihelion, so that essentially most of the organic products on the surface would be sublimed, blown off or polymerized. 2. Because of the low temperatures of the cometary ices, polymers formed on one perihelion passage would not migrate deep enough into the nucleus to be preserved before they would be ablated away by the next perihelion passage. 3. In the absence of atmosphere, and discrete liquid and solid surfaces, it is difficult to visualize the synthesis of key life molecules, such as oligopeptides, oligonucleotides and phospholipids by condensation and dehydration reactions as is presumed to have occurred in the evaporating ponds of the primitive Earth. 4. Observations suggest that cometary nuclei have a rather weak structure. Hence, the low central pressures in comets combined with the high vapor pressures of cometary ices at the melting point of water ice, suggest that a liquid core is not a tenable structure. Yet, even if a cometary nucleus is compact enough to hold a liquid core and a transient liquid water environment was provided by the decay of26Al, the continuous irradiation in water of most of the biologically relevant polymers would have hydrolyzed and degraded them. 5. Needless to say that the effects of radiation on self-replicating systems would also have caused the demise of any life forms which may have appeared under any
Coexistence of collective and non-collective structures in the odd-A f{sub 7/2} nuclei
Energy Technology Data Exchange (ETDEWEB)
Bednarczyk, P.; Styczen, J.; Broda, R. [The H. Niewodniczanski Inst. of Nuclear Physics, Cracow (Poland)] [and others
1996-09-01
High-spin states in {sup 43}Ca, {sup 45}Sc, and {sup 45}Ti were studied with the GASP multidetector array coupled with the Recoil Mass Spectrometer. The nuclei were excited in the 60 MeV {sup 18}O +{sup 30}Si reaction. Lifetimes were extracted from the analysis of the Doppler-shift attenuation of {gamma}-rays observed in the reversed {sup 35}Cl+{sup 12}C reaction. The measurements suggest significant deformations of the positive-parity intruder bands in {sup 45}Sc and {sup 45}Ti. These bands are predicted by the mean-field calculations to be the cross-shell particle-hole excitation associated with a strong quadrupole core-polarization. Spherical shell-model calculations reproduce observed excitation energies and transition rates in both spherical and deformed structures. (author) 24 refs, 3 figs, 1 tab
Fraktalnist deformational relief polycrystalline aluminum
Directory of Open Access Journals (Sweden)
М.В. Карускевич
2006-02-01
Full Text Available The possibility of the fractal geometry method application for the analisys of surface deformation structures under cyclic loading is presented.It is shown, that deformation relief of the alclad aluminium alloyes meets the criteria of the fractality. For the fractal demention estimation the method of “box-counting”can be applied.
Permanent deformation of asphalt mixes
Molenaar, A.A.A.; Van de Ven, M.F.C.; Muraya, P.M.
This dissertation describes the results of a research that was conducted on the permanent deformation of asphalt mixtures. Central to this research was the separate characterization of the contribution of the aggregate skeleton and the bituminous mortar towards resistance to permanent deformation.
Permanent deformation of asphalt mixes
Muraya, P.M.
2007-01-01
This dissertation describes the results of a research that was conducted on the permanent deformation of asphalt mixtures. Central to this research was the separate characterization of the contribution of the aggregate skeleton and the bituminous mortar towards resistance to permanent deformation.
Metastable vacua and geometric deformations
Amariti, A; Girardello, L; Mariotti, A
2008-01-01
We study the geometric interpretation of metastable vacua for systems of D3 branes at non isolated toric deformable singularities. Using the L^{aba} examples, we investigate the relations between the field theoretic susy breaking and restoration and the complex deformations of the CY singularities.
Deformation of Man Made Objects
Ibrahim, Mohamed
2012-07-01
We introduce a framework for 3D object deformation with primary focus on man-made objects. Our framework enables a user to deform a model while preserving its defining characteristics. Moreover, our framework enables a user to set constraints on a model to keep its most significant features intact after the deformation process. Our framework supports a semi-automatic constraint setting environment, where some constraints could be automatically set by the framework while others are left for the user to specify. Our framework has several advantages over some state of the art deformation techniques in that it enables a user to add new features to the deformed model while keeping its general look similar to the input model. In addition, our framework enables the rotation and extrusion of different parts of a model.
Chaotic motion in axially symmetric potentials with oblate quadrupole deformation
Energy Technology Data Exchange (ETDEWEB)
Letelier, Patricio S. [Departamento de Matematica Aplicada, IMECC, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil); Ramos-Caro, Javier, E-mail: javier@ime.unicamp.br [Departamento de Matematica Aplicada, IMECC, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil); Lopez-Suspes, Framsol, E-mail: framsol@gmail.com [Facultad de Telecomunicaciones, Universidad Santo Tomas and Escuela de Fisica, Universidad Industrial de Santander, Bucaramanga (Colombia)
2011-10-03
By computing the Poincare's surfaces of section and Lyapunov exponents, we study the effect of introducing an oblate quadrupole in the dynamics associated with two generic spherical potentials of physical interest: the central monopole and the isotropic harmonic oscillator. In the former case we find saddle points in the effective potential, in contrast to the statements presented by Gueron and Letelier in [E. Gueron, P.S. Letelier, Phys. Rev. E 63 (2001) 035201]. The results we show in the second case have application in nuclear or atomic physics. In particular, we find values of oblate deformation leading to a disappearance of shell structure in the single-particle spectrum. -- Highlights: → We find chaotic motion around a monopole with oblate quadrupole deformation. → This corrects the statements introduced in [E. Gueron, P.S. Letelier, Phys. Rev. E 63 (2001) 035201]. → We present an alternative model for the potential due to an oblate deformed nuclei. → This leads to stochastic regions in the phase space of classical orbits. → It suggests that the shell structure of single-particle spectrum tends to disappear.
Cloud Condensation Nuclei in Fire-3
2000-01-01
The centerpiece of this research was the cloud condensation nuclei (CCN) measurements of the Desert Research Institute (DRI) CCN spectrometers on board the NCAR C-130 aircraft during the Arctic Cloud Experiment (ACE) in May, 1998. These instruments operated successfully throughout all eight 10-hour research flights based in Fairbanks and the two ferry flights between Colorado and Fairbanks. Within a few months of completion of ACE the CCN data was edited and put into the archives. A paper was completed and published on the CCN climatology during the previous two FIRE field projects-FIRE 1 based in San Diego in June and July, 1987 and ASTEX based in the Azores Islands in June, 1992. This showed distinct contrasts in concentrations and spectra between continental and maritime CCN concentrations, which depended on air mass trajectories. Pollution episodes from Europe had distinct influences on particle concentrations at low altitudes especially within the boundary layer. At higher altitudes concentrations were similar in the two air mass regimes. Cloudier atmospheres showed lower concentrations especially below the clouds, which were a result mostly of coalescence scavenging.
Photodisintegration of Light Nuclei with CLAS
Energy Technology Data Exchange (ETDEWEB)
Ilieva, Yordanka Yordanova [University of South Carolina; Zachariou, Nicholas [University of South Carolina
2013-08-01
We report preliminary results of photodisintegration of deuteron and {sup 3}He measured with CLAS at Jefferson Lab. We have extracted the beam-spin asymmetry for the {vector {gamma}}d {yields} pn reaction at photon energies from 1.1 GeV to 2.3 GeV and proton center-of-mass (c.m.) angles between 35{degrees} and 135{degrees} . Our data show interesting evolution of the angular dependence of the observable as the photon energy increases. The energy dependence of the beam-spin asymmetry at 90 shows a change of slope at photon energy of 1.6 GeV. A comparison of our data with model calculations suggests that a fully non-perturbative treatment of the underlying dynamics may be able to describe the data better than a model based on hard scattering. We have observed onset of dimensional scaling in the cross section of two-body photodisintegration of {sup 3}He at remarkably low energy and momentum transfer, which suggests that partonic degrees of freedom may be relevant for the description of nuclei at energies lower than previously considered.
A New Thermodynamics from Nuclei to Stars
Directory of Open Access Journals (Sweden)
Dieter H.E. Gross
2004-03-01
Full Text Available Abstract: Equilibrium statistics of Hamiltonian systems is correctly described by the microcanonical ensemble. Classically this is the manifold of all points in the N-body phase space with the given total energy. Due to Boltzmann's principle, eS=tr(ÃŽÂ´(E-H, its geometrical size is related to the entropy S(E,N,.... This definition does not invoke any information theory, no thermodynamic limit, no extensivity, and no homogeneity assumption, as are needed in conventional (canonical thermo-statistics. Therefore, it describes the equilibrium statistics of extensive as well of non-extensive systems. Due to this fact it is the fundamental definition of any classical equilibrium statistics. It can address nuclei and astrophysical objects as well. All kind of phase transitions can be distinguished sharply and uniquely for even small systems. It is further shown that the second law is a natural consequence of the statistical nature of thermodynamics which describes all systems with the same -- redundant -- set of few control parameters simultaneously. It has nothing to do with the thermodynamic limit. It even works in systems which are by far than any thermodynamic "limit".
Broadband properties of active galactic nuclei
Edelson, Richard Allen
The broadband radio-infrared-optical-ultraviolet properties of active galactic nuclei are used to investigate the nature of the central engine and the surrounding environment. Optically selected quasars and Seyfert 1 galaxies tend to have relatively flat infrared spectra and low reddenings, while most Seyfert 2 galaxies and other dusty objects have steep infrared spectra and larger reddenings. The infrared spectra of most luminous radio-quiet active galaxies turn over near approx. 80 micron. It appears that the infrared spectra of most quasars and luminous Seyfert 1 galaxies are dominated by unreprocessed radiation from a synchrotron self-absorbed source of order a light day across, about the size of the hypothesized accretion disk. Seyfert 2 galaxies and other reddened objects have infrared spectra which appear to be dominated by thermal emission from warm dust, probably in the disk of the underlying galaxy. A broad emission feature, centered near 5 micron, is present in many luminous quasars and Seyfert 1 galaxies. Highly polarized objects (blazars) can be strongly variable at far infrared wavelengths over time scales of months. Seyfert galaxies tend to have steep radio spectra.
Active galactic nuclei: what's in a name?
Padovani, P.; Alexander, D. M.; Assef, R. J.; De Marco, B.; Giommi, P.; Hickox, R. C.; Richards, G. T.; Smolčić, V.; Hatziminaoglou, E.; Mainieri, V.; Salvato, M.
2017-08-01
Active galactic nuclei (AGN) are energetic astrophysical sources powered by accretion onto supermassive black holes in galaxies, and present unique observational signatures that cover the full electromagnetic spectrum over more than twenty orders of magnitude in frequency. The rich phenomenology of AGN has resulted in a large number of different "flavours" in the literature that now comprise a complex and confusing AGN "zoo". It is increasingly clear that these classifications are only partially related to intrinsic differences between AGN and primarily reflect variations in a relatively small number of astrophysical parameters as well the method by which each class of AGN is selected. Taken together, observations in different electromagnetic bands as well as variations over time provide complementary windows on the physics of different sub-structures in the AGN. In this review, we present an overview of AGN multi-wavelength properties with the aim of painting their "big picture" through observations in each electromagnetic band from radio to γ -rays as well as AGN variability. We address what we can learn from each observational method, the impact of selection effects, the physics behind the emission at each wavelength, and the potential for future studies. To conclude, we use these observations to piece together the basic architecture of AGN, discuss our current understanding of unification models, and highlight some open questions that present opportunities for future observational and theoretical progress.
Active Galactic Nuclei outflows in galaxy discs
Hartwig, Tilman; Volonteri, Marta; Dashyan, Gohar
2018-01-01
Galactic outflows, driven by active galactic nuclei (AGN), play a crucial role in galaxy formation and in the self-regulated growth of supermassive black holes. AGN feedback couples to and affects gas, rather than stars, and in many, if not most, gas-rich galaxies cold gas is rotationally supported and settles in a disc. We present a 2D analytical model for AGN-driven outflows in a gaseous disc and demonstrate the main improvements, compared to existing 1D solutions. We find significant differences for the outflow dynamics and wind efficiency. The outflow is energy-driven due to inefficient cooling up to a certain AGN luminosity (˜1043 erg s-1 in our fiducial model), above which the outflow remains momentum-driven in the disc up to galactic scales. We reproduce results of 3D simulations that gas is preferentially ejected perpendicular to the disc and find that the fraction of ejected interstellar medium is lower than in 1D models. The recovery time of gas in the disc, defined as the freefall time from the radius to which the AGN pushes the ISM at most, is remarkably short, of the order 1 Myr. This indicates that AGN-driven winds cannot suppress BH growth for long. Without the inclusion of supernova feedback, we find a scaling of the black hole mass with the halo velocity dispersion of MBH∝σ4.8.
Nuclei far from stability using exotic targets
Wilhelmy, J B; Brown, R E; Flynn, E R; Thomas, K E; Van der Plicht, J
1981-01-01
The meson factories have made possible high fluence medium energy proton beams that can be used for spallation reactions to produce macro quantities of unstable isotopes. Targets of over 10 g/cm/sup 2/ can be exposed to total fluence approaching 1 A-hour resulting in spallation yields in the 0.01-10 mg range for many isotopes of potential interest for nuclear structure studies. With the use of hot cell facilities, chemical processing can isolate the desired material and this coupled with subsequent isotope separation can result in usable quantities of material for nuclear target application. With offstable isotopes as target materials, conventional nuclear spectroscopy techniques can be employed to study nuclei far from stability. The irradiation and processing requirements for such an operation, along with the isotope production possibilities, are discussed. Also presented are initial experiments using a /sup 148/Gd (t/sub 1/2/=75a) target to perform the (p, t) reaction to establish levels in the proposed do...
High spins in gamma-soft nuclei
Energy Technology Data Exchange (ETDEWEB)
Leander, G.A.; Frauendorf, S.; May, F.R.
1982-01-01
Nuclei which are soft with respect to the ..gamma.. shape degree of freedom are expected to have many different structures coexisting in the near-yrast regime. In particular, the lowest rotational quasi-particle in a high-j shell exerts a strong polarizing effect on ..gamma... The ..gamma.. to which it drives is found to vary smoothly over a 180/sup 0/ range as the position of the Fermi level varies. This simple rule is seen to have a direct connection with the energy staggering of alternate spin states in rotational bands. A diagram is presented which provides a general theoretical reference for experimental tests of the relation between ..gamma.., spin staggering, configuration, and nucleon number. In a quasicontinuum spectrum, the coexistence of different structures are expected to make several unrelated features appear within any one slice of sum energy and multiplicity. However, it is also seen that the in-band moment of inertia may be similar for many bands of different ..gamma...
Electromagnetic Studies of Mesons, Nucleons, and Nuclei
Energy Technology Data Exchange (ETDEWEB)
Baker, Oliver K.
2013-08-20
Professor Baker was a faculty member at Hampton University in Hampton, Virginia, and, jointly, a Staff Physicist at Jefferson Lab in nearby Newport News from September 1989 to July 2006. The Department of Energy (DOE) funded the grant DE-FG02-97ER41035 Electromagnetic Studies of Mesons, Nucleons, and Nuclei, while Baker was in this joint appointment. Baker sent a closeout report on these activities to Hampton University’s Sponsored Research Office some years ago, shortly after joining Yale University in 2006. In the period around 2001, the research grant with Baker as the Principal Investigator (PI) was put under the supervision of Professor Liguang Tang at Hampton University. Baker continued to pursue the research while in this join appointment, however the administrative responsibilities with the DOE and with Hampton University rested with Professor Tang after 2001, to my recollection. What is written in this document is from Baker’s memory of the research activities, which he has not pursued since joining the Yale University faculty.
Calorimetric signatures of human cancer cells and their nuclei
Energy Technology Data Exchange (ETDEWEB)
Todinova, S. [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113 (Bulgaria); Stoyanova, E. [Department of Molecular Immunology, Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Tzarigradsko shose Blvd. 73, Sofia 1113 (Bulgaria); Krumova, S., E-mail: sakrumo@gmail.com [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113 (Bulgaria); Iliev, I. [Institute of Experimental Morphology, Pathology and Anthropology with Museum, Acad. G. Bonchev Str., Bl. 25, Sofia 1113 (Bulgaria); Taneva, S.G. [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113 (Bulgaria)
2016-01-10
Graphical abstract: - Highlights: • Two temperature ranges are distinguished in the thermograms of cells/nuclei. • Different thermodynamic properties of cancer and normal human cells/nuclei. • Dramatic reduction of the enthalpy of the low-temperature range in cancer cells. • Oxaliplatin and 5-FU affect the nuclear matrix proteins and the DNA stability. - Abstract: The human cancer cell lines HeLa, JEG-3, Hep G2, SSC-9, PC-3, HT-29, MCF7 and their isolated nuclei were characterized by differential scanning calorimetry. The calorimetric profiles differed from normal human fibroblast (BJ) cells in the two well distinguished temperature ranges—the high-temperature range (H{sub T}, due to DNA-containing structures) and the low-temperature range (L{sub T}, assigned to the nuclear matrix and cellular proteins). The enthalpy of the L{sub T} range, and, respectively the ratio of the enthalpies of the L{sub T}- vs. H{sub T}-range, ΔH{sub L}/ΔH{sub H}, is strongly reduced for all cancer cells compared to normal fibroblasts. On the contrary, for most of the cancer nuclei this ratio is higher compared to normal nuclei. The HT-29 human colorectal cancer cells/nuclei differed most drastically from normal human fibroblast cells/nuclei. Our data also reveal that the treatment of HT-29 cancer cells with cytostatic drugs affects not only the DNA replication but also the cellular proteome.
Synthesis of Neutron Enriched Heavy and Superheavy Nuclei
Zagrebaev, V. I.; Karpov, A. V.; Greiner, Walter
2014-09-01
Applicability of different nuclear reactions (fusion of stable and radioactive nuclei, multi-nucleon transfers and neutron capture) for the production of new neutron enriched heavy nuclei is discussed in the paper. For the first time, a narrow pathway is found to the middle of the island of stability owing to possible β+-decay of SH isotopes which can be formed in ordinary fusion reactions of stable nuclei. Neutron capture reactions can be also used for the production of the long-living neutron rich SH nuclei. Strong neutron fluxes might be provided by pulsed nuclear reactors and by multiple nuclear explosions in laboratory conditions and by supernova explosions in nature. Low-energy multinucleon transfer reactions with actinide beams and targets are of special interest for synthesis of new neutron enriched transfermium nuclei and not-yet-known nuclei around the closed neutron shell N = 126 having largest impact on astrophysical r process. The estimated cross sections for the production of these nuclei look very promising to plan such experiments at available accelerators. Several new test experiments of such kind are proposed to perform including those in which a role of the shell effects in low-energy reaction dynamics could be clarify much better.
Incidence of centrally positioned nuclei in mouse masticatory muscle fibers
DEFF Research Database (Denmark)
Vilmann, A; Vilmann, H; Kirkeby, S
1989-01-01
Cross-sections of normal digastric, temporalis and masseter muscles from 7- and 30-week-old mice were studied for centrally positioned nuclei. Such nuclei were inhomogeneously distributed throughout each muscle and varied markedly between specimens. The incidence of centrally positioned nuclei in......, the frequency in a given muscle was apparently age-independent. A connection between fiber type and centrally positioned nuclei is suggested.......Cross-sections of normal digastric, temporalis and masseter muscles from 7- and 30-week-old mice were studied for centrally positioned nuclei. Such nuclei were inhomogeneously distributed throughout each muscle and varied markedly between specimens. The incidence of centrally positioned nuclei...... in the digastric muscle (mean +/- SD: 0.029 +/- 0.015, n = 25) was significantly higher (p less than 0.001) than that in the temporalis (mean +/- SD: 0.011 +/- 0.010, n = 25) and masseter muscles (mean +/- SD: 0.005 +/- 0.007, n = 9), but did not differ between the two latter muscles (p = 0.41). Furthermore...
Rotational isovector vibrations in titanium nuclei
Energy Technology Data Exchange (ETDEWEB)
Faessler, A.; Nojarov, R.; Taigel, T.
1989-01-30
The strong M1 states with K/sup ..pi../ = 1/sup +/ in /sup 44,46,48,50/Ti are described microscopically with a deformed Woods-Saxon potential plus QRPA using a parameter-free self-consistent quadrupole force and an interaction, which restores the rotational symmetry. The available experimental data (energies, B(M1) values and (e,e') form factors in /sup 46,48/Ti) are well described in terms of isovector quadrupole rotational vibrations. These RPA states correspond to the scissor-type of isovector motion described by the two-rotor model, but they overlap only 20-30% with the collective isovector rotational state of this model since only few quasiparticle configurations take part in the RPA rotational vibration.
The intergalactic propagation of ultrahigh energy cosmic ray nuclei
Energy Technology Data Exchange (ETDEWEB)
Hooper, Dan; /Fermilab; Sarkar, Subir; /Oxford U., Theor. Phys.; Taylor, Andrew M.; /Oxford U.
2006-08-01
We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).
New aspects of the neutron capture in light nuclei
Energy Technology Data Exchange (ETDEWEB)
Mengoni, A. [Institute of Physical and Chemical Research, Wako, Saitama (Japan)
1997-03-01
Several neutron capture cross sections of light nuclei (A {<=} 40) for neutron energies up to the MeV region have been recently calculated. Examples are (target nuclei): {sup 12}C, {sup 13}C, {sup 16}O and {sup 10}Be. The results of these calculations will be shown together with a comparison with the most recent experimental data. In the case of n + {sup 10}Be case, the cross section of the inverse process (Coulomb dissociation of {sup 11}Be) is considered and compared with the measurement. A discussion on the relevant nuclear structure information required for the evaluation of nuclear data of light nuclei is given. (author)
On infinitesimal conformai deformations of surfaces
Directory of Open Access Journals (Sweden)
Юлия Степановна Федченко
2014-11-01
Full Text Available A new form of basic equations for conformai deformations is found. The equations involve tensor fields of displacement vector only. Conditions for trivial deformations as well as infinitesimal conformai deformations are studied.
Correlated basis functions theory of light nuclei. Pt. 2. Spectra of light nuclei
Energy Technology Data Exchange (ETDEWEB)
Guardiola, R.; Bosca, M.C.
1988-11-14
This work is a continuation of a previous one devoted to the study of ground-state energies of p-shell nuclei using the correlated basis functions theory. Here, the low-lying excited levels are computed and compared with experiment. This study has no free parameters, and everything is directly obtained from a realistic Reid V8 nucleon-nucleon interaction. As expected, we do not obtain quantitative agreement with the experimental levels. However, many of the qualitative characteristics of the spectrum emerge naturally.
Perceptual transparency from image deformation
Kawabe, Takahiro; Maruya, Kazushi; Nishida, Shin’ya
2015-01-01
Human vision has a remarkable ability to perceive two layers at the same retinal locations, a transparent layer in front of a background surface. Critical image cues to perceptual transparency, studied extensively in the past, are changes in luminance or color that could be caused by light absorptions and reflections by the front layer, but such image changes may not be clearly visible when the front layer consists of a pure transparent material such as water. Our daily experiences with transparent materials of this kind suggest that an alternative potential cue of visual transparency is image deformations of a background pattern caused by light refraction. Although previous studies have indicated that these image deformations, at least static ones, play little role in perceptual transparency, here we show that dynamic image deformations of the background pattern, which could be produced by light refraction on a moving liquid’s surface, can produce a vivid impression of a transparent liquid layer without the aid of any other visual cues as to the presence of a transparent layer. Furthermore, a transparent liquid layer perceptually emerges even from a randomly generated dynamic image deformation as long as it is similar to real liquid deformations in its spatiotemporal frequency profile. Our findings indicate that the brain can perceptually infer the presence of “invisible” transparent liquids by analyzing the spatiotemporal structure of dynamic image deformation, for which it uses a relatively simple computation that does not require high-level knowledge about the detailed physics of liquid deformation. PMID:26240313
Energy Technology Data Exchange (ETDEWEB)
Sfetsos, Konstadinos [Department of Nuclear and Particle Physics, Faculty of Physics, University of Athens,Athens 15784 (Greece); Thompson, Daniel C. [Theoretische Natuurkunde, Vrije Universiteit Brussel andThe International Solvay Institutes,Pleinlaan 2, B-1050, Brussels (Belgium)
2014-12-29
We examine a recently proposed class of integrable deformations to two-dimensional conformal field theories. These λ-deformations interpolate between a WZW model and the non-Abelian T-dual of a Principal Chiral Model on a group G or, between a G/H gauged WZW model and the non-Abelian T-dual of the geometric coset G/H. λ-deformations have been conjectured to represent quantum group q-deformations for the case where the deformation parameter is a root of unity. In this work we show how such deformations can be given an embedding as full string backgrounds whose target spaces satisfy the equations of type-II supergravity. One illustrative example is a deformation of the Sl(2,ℝ)/U(1) black-hole CFT. A further example interpolates between the ((SU(2)×SU(2))/(SU(2)))×((SL(2,ℝ)×SL(2,ℝ))/(SL(2,ℝ)))×U(1){sup 4} gauged WZW model and the non-Abelian T-dual of AdS{sub 3}×S{sup 3}×T{sup 4} supported with Ramond flux.
The parton distributions in nuclei and in polarized nucleons
Energy Technology Data Exchange (ETDEWEB)
Close, F.E.
1988-01-01
The emerging information was reviewed on the way quark and anti-quark, and gluon distributions are modified in nuclei relative to free nucleons. Some implications of the recent data on polarized leptoproduction are discussed. 27 refs., 6 figs.
Structure of proton-rich nuclei of astrophysical interest
Energy Technology Data Exchange (ETDEWEB)
Roeckl, E. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany)
1998-06-01
Recent experimental data concerning proton-rich nuclei between A=20 and A=100 are presented and discussed with respect to their relevance to the astrophysical rp process and to the calibration of solar neutrino detectors. (orig.)
Population of Nuclei Via 7Li-Induced Binary Reactions
Energy Technology Data Exchange (ETDEWEB)
Clark, Rodney M.; Phair, Larry W.; Descovich, M.; Cromaz, Mario; Deleplanque, M.A.; Fall on, Paul; Lee, I-Yang; Macchiavelli, A.O.; McMahan, Margaret A.; Moretto, Luciano G.; Rodriguez-Vieitez, E.; Sinha,Shrabani; Stephens, Frank S.; Ward, David; Wiedeking, Mathis
2005-08-08
The authors have investigated the population of nuclei formed in binary reactions involving {sup 7}Li beams on targets of {sup 160}Gd and {sup 184}W. The {sup 7}Li + {sup 184}W data were taken in the first experiment using the LIBERACE Ge-array in combination with the STARS Si {Delta}E-E telescope system at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory. By using the Wilczynski binary transfer model, in combination with a standard evaporation model, they are able to reproduce the experimental results. This is a useful method for predicting the population of neutron-rich heavy nuclei formed in binary reactions involving beams of weakly bound nuclei formed in binary reactions involving beams of weakly bound nuclei and will be of use in future spectroscopic studies.
Light element production by low energy nuclei from massive stars
Vangioni-Flam, E.; Casse, M.; Ramaty, R.
1997-01-01
The Orion complex is a source of gamma rays attributed to the de-excitation of fast carbon and oxygen nuclei excited through interactions with ambient hydrogen and helium. This has consequences for the production and evolution of light isotopes in the Galaxy, as massive stars appear as prolific sources of C-O rich low energy nuclei. The different stages of massive star evolution are considered in relation to the acceleration of nuclei to moderate energies. It is concluded that the low energy nuclear component originating from massive stars plays a larger role than the usual Galactic cosmic rays in shaping the evolution of Li-6, Be-9, B-10 and B-11, especially in the early Galactic evolution. The enhancement of the B-11/B-10 ratio observed in meteorites and in the interstellar medium is attributed to the interaction of low energy carbon nuclei with ambient H and to a lesser degree, to neutrino spallation.
The structure of rotational bands in alpha-cluster nuclei
Directory of Open Access Journals (Sweden)
Bijker Roelof
2015-01-01
Full Text Available In this contribution, I discuss an algebraic treatment of alpha-cluster nuclei based on the introduction of a spectrum generating algebra for the relative motion of the alpha-clusters. Particular attention is paid to the discrete symmetry of the geometric arrangement of the α-particles, and the consequences for the structure of the rotational bands in the 12C and 16O nuclei.
Introduction to the study of collisions between heavy nuclei
Energy Technology Data Exchange (ETDEWEB)
Bayman, B.F.
1980-01-01
Current investigations concerning the collisions of nuclei governed by small de Broglie wavelengths are reviewed. The wave packets localize nuclei in regions small compared to their diameters. Cross sections are examined for potential scattering, elastic scattering, quasi-molecular states, peripheral particle-transfer reactions, fusion, and deep inelastic collisions. Theories of fusion and deep inelastic collisions are summarized. This paper is in the nature of a review-tutorial. 45 references, 51 figures, 2 tables. (RWR)
Theoretical Study of Structure and Synthesis Mechanism of Superheavy Nuclei
Zhou, Shan-Gui
The study of superheavy nuclei (SHN) is on the frontier of modern nuclear physics. In recent years, we have carried out theoretical investigations of both the structure properties and the synthesis mechanism of SHN. In this contribution, we briefly review these progresses and focus on the study of potential energy surfaces and fission barriers of actinide nuclei by using the MDC-RMF model and that of the fusion mechanism by using the ImQMD model.
Energy systematics of heavy nuclei -- mean field models in comparison
Reinhard, P. -G.; Agrawal, B. K.
2010-01-01
We compare the systematics of binding energies computed within the standard and extended versions of the relativistic mean-field (RMF) model and the Skyrme Hartree-Fock (SHF) model. The general trends for the binding energies for super-heavy nuclei are significantly different for these models. The SHF models tend to underbind the superheavy nuclei, while, RMF models show just the opposite trend. The extended RMF model seems to provide remarkable improvements over the results obtained for the ...
Central vestibular system: vestibular nuclei and posterior cerebellum.
Barmack, Neal H
2003-06-15
The vestibular nuclei and posterior cerebellum are the destination of vestibular primary afferents and the subject of this review. The vestibular nuclei include four major nuclei (medial, descending, superior and lateral). In addition, smaller vestibular nuclei include: Y-group, parasolitary nucleus, and nucleus intercalatus. Each of the major nuclei can be subdivided further based primarily on cytological and immunohistochemical histological criteria or differences in afferent and/or efferent projections. The primary afferent projections of vestibular end organs are distributed to several ipsilateral vestibular nuclei. Vestibular nuclei communicate bilaterally through a commissural system that is predominantly inhibitory. Secondary vestibular neurons also receive convergent sensory information from optokinetic circuitry, central visual system and neck proprioceptive systems. Secondary vestibular neurons cannot distinguish between sources of afferent activity. However, the discharge of secondary vestibular neurons can distinguish between "active" and "passive" movements. The posterior cerebellum has extensive afferent and efferent connections with vestibular nuclei. Vestibular primary afferents are distributed to the ipsilateral uvula-nodulus as mossy fibers. Vestibular secondary afferents are distributed bilaterally. Climbing fibers to the cerebellum originate from two subnuclei of the contralateral inferior olive; the dorsomedial cell column and beta-nucleus. Vestibular climbing fibers carry information only from the vertical semicircular canals and otoliths. They establish a coordinate map, arrayed in sagittal zones on the surface of the uvula-nodulus. Purkinje cells respond to vestibular stimulation with antiphasic modulation of climbing fiber responses (CFRs) and simple spikes (SSs). The modulation of SSs is out of phase with the modulation of vestibular primary afferents. Modulation of SSs persists, even after vestibular primary afferents are destroyed by a
Non-linear elastic deformations
Ogden, R W
1997-01-01
Classic in the field covers application of theory of finite elasticity to solution of boundary-value problems, analysis of mechanical properties of solid materials capable of large elastic deformations. Problems. References.
Nonlinear Deformable-body Dynamics
Luo, Albert C J
2010-01-01
"Nonlinear Deformable-body Dynamics" mainly consists in a mathematical treatise of approximate theories for thin deformable bodies, including cables, beams, rods, webs, membranes, plates, and shells. The intent of the book is to stimulate more research in the area of nonlinear deformable-body dynamics not only because of the unsolved theoretical puzzles it presents but also because of its wide spectrum of applications. For instance, the theories for soft webs and rod-reinforced soft structures can be applied to biomechanics for DNA and living tissues, and the nonlinear theory of deformable bodies, based on the Kirchhoff assumptions, is a special case discussed. This book can serve as a reference work for researchers and a textbook for senior and postgraduate students in physics, mathematics, engineering and biophysics. Dr. Albert C.J. Luo is a Professor of Mechanical Engineering at Southern Illinois University, Edwardsville, IL, USA. Professor Luo is an internationally recognized scientist in the field of non...
Axisymmetric finite deformation membrane problems
Energy Technology Data Exchange (ETDEWEB)
Feng, W.W.
1980-12-12
Many biomechanic problems involve the analysis of finite deformation axisymmetric membranes. This paper presents the general formulation for solving a class of axisymmetric membrane problems. The material nonlinearity, as well as the geometric nonlinearity, is considered. Two methods are presented to solve these problems. The first method is solving a set of differential equilibrium equations. The governing equations are reduced to three first-order ordinary-differential equations with explicit derivatives. The second method is the Ritz method where a general potential energy functional valid for all axisymmetric deformed positions is presented. The geometric admissible functions that govern the deformed configuration are written in terms of a series with unknown coefficients. These unknown coefficients are determined by the minimum potential energy principle that of all geometric admissible deformed configurations, the equilibrium configuration minimizes the potential energy. Some examples are presented. A comparison between these two methods is mentioned.
Characteristic classes in deformation quantization
Willwacher, Thomas
2015-01-01
In deformation quantization, one can associate five characteristic functions to (stable) formality morphisms on cochains and chains and to "two-brane" formality morphisms. We show that these characteristic functions agree.
Active Galactic Nuclei Feedback and Galactic Outflows
Sun, Ai-Lei
Feedback from active galactic nuclei (AGN) is thought to regulate the growth of supermassive black holes (SMBHs) and galaxies. The most direct evidence of AGN feedback is probably galactic outflows. This thesis addresses the link between SMBHs and their host galaxies from four different observational perspectives. First, I study the local correlation between black hole mass and the galactic halo potential (the MBH - Vc relation) based on Very Large Array (VLA) HI observations of galaxy rotation curves. Although there is a correlation, it is no tighter than the well-studied MBH - sigma* relation between the black hole mass and the potential of the galactic bulge, indicating that physical processes, such as feedback, could link the evolution of the black hole to the baryons in the bulge. In what follows, I thus search for galactic outflows as direct evidence of AGN feedback. Second, I use the Atacama Large Millimeter Array (ALMA) to observe a luminous obscured AGN that hosts an ionized galactic outflow and find a compact but massive molecular outflow that can potentially quench the star formation in 10. 6 years.The third study extends the sample of known ionized outflows with new Magellan long-slit observations of 12 luminous obscured AGN. I find that most luminous obscured AGN (Lbol > 1046 ergs s-1) host ionized outflows on 10 kpc scales, and the size of the outflow correlates strongly with the luminosity of the AGN. Lastly, to capitalize on the power of modern photometric surveys, I experiment with a new broadband imaging technique to study the morphology of AGN emission line regions and outflows. With images from the Sloan Digital Sky Survey (SDSS), this method successfully constructs images of the [OIII]lambda5007 emission line and reveals hundreds of extended emission-line systems. When applied to current and future surveys, such as the Large Synoptic Survey Telescope (LSST), this technique could open a new parameter space for the study of AGN outflows. In
The Structure of Active Galactic Nuclei
Kriss, Gerard A.
1997-06-01
We are continuing our systematic investigation of the nuclear structure of nearby active galactic nuclei (AGN). Upon completion, our study will characterize hypothetical constructs such as narrow-line clouds, obscuring tori, nuclear gas disks. and central black holes with physical measurements for a complete sample of nearby AGN. The major scientific goals of our program are: (1) the morphology of the NLR; (2) the physical conditions and dynamics of individual clouds in the NLR; (3) the structure and physical conditions of the warm reflecting gas; (4) the structure of the obscuring torus; (5) the population and morphology of nuclear disks/tori in AGN; (6) the physical conditions in nuclear disks; and (7) the masses of central black holes in AGN. We will use the Hubble Space Telescope (HST) to obtain high-resolution images and spatially resolved spectra. Far-UV spectroscopy of emission and absorption in the nuclear regions using HST/FOS and the Hopkins Ultraviolet Telescope (HUT) will help establish physical conditions in the absorbing and emitting gas. By correlating the dynamics and physical conditions of the gas with the morphology revealed through our imaging program, we will be able to examine mechanisms for fueling the central engine and transporting angular momentum. The kinematics of the nuclear gas disks may enable us to measure the mass of the central black hole. Contemporaneous X-ray observations using ASCA will further constrain the ionization structure of any absorbing material. Monitoring of variability in the UV and X-ray absorption will be used to determine the location of the absorbing gas, possibly in the outflowing warm reflecting gas, or the broad-line region, or the atmosphere of the obscuring torus. Supporting ground-based observations in the optical, near-IR, imaging polarimetry, and the radio will complete our picture of the nuclear structures. With a comprehensive survey of these characteristics in a complete sample of nearby AGN, our
Global variability of cloud condensation nuclei concentrations
Makkonen, Risto; Krüger, Olaf
2017-04-01
Atmospheric aerosols can influence cloud optical and dynamical processes by acting as cloud condensation nuclei (CCN). Globally, these indirect aerosol effects are significant to the radiative budget as well as a source of high uncertainty in anthropogenic radiative forcing. While historically many global climate models have fixed CCN concentrations to a certain level, most state-of-the-art models calculate aerosol-cloud interactions with sophisticated methodologies based on interactively simulated aerosol size distributions. However, due to scarcity of atmospheric observations simulated global CCN concentrations remain poorly constrained. Here we assess global CCN variability with a climate model, and attribute potential trends during 2000-2010 to changes in emissions and meteorological fields. Here we have used ECHAM5.5-HAM2 with model M7 microphysical aerosol model. The model has been upgraded with a secondary organic aerosol (SOA) scheme including ELVOCs. Dust and sea salt emissions are calculated online, based on wind speed and hydrology. Each experiment is 11 years, analysed after a 6-month spin-up period. The MODIS CCN product (Terra platform) is used to evaluate model performance throughout 2000-2010. While optical remote observation of CCN column includes several deficiencies, the products serves as a proxy for changes during the simulation period. In our analysis we utilize the observed and simulated vertical column integrated CCN concentration, and limit our analysis only over marine regions. Simulated annual CCN column densities reach 2ṡ108 cm-2 near strong source regions in central Africa, Arabian Sea, Bay of Bengal and China sea. The spatial concentration gradient in CCN(0.2%) is steep, and column densities drop to <50% a few hundred kilometers away from the coasts. While the spatial distribution of CCN at 0.2% supersaturation is closer to that of MODIS proxy, as opposed to 1.0% supersaturation, the overall column integrated CCN are too low. Still
Axially deformed relativistic Hartree Bogoliubov theory with a separable pairing force
Tian, Yuan; Ma, Zhong-Yu; Ring, P.
2009-08-01
A separable form of pairing interaction in the 1S0 channel has been introduced and successfully applied in the description of both static and dynamic properties of superfluid nuclei. By adjusting the parameters to reproduce the pairing properties of the Gogny force in nuclear matter, this separable pairing force is successful in depicting the pairing properties of ground states and vibrational excitations of spherical nuclei on almost the same footing as the original Gogny force. In this article, we extend these investigations for relativistic Hartree-Bogoliubov theory in deformed nuclei with axial symmetry (RHBZ) using the same separable pairing interaction. To preserve translational invariance we construct one- and two-dimensional Talmi-Moshinsky brackets for the cylindrical harmonic oscillator basis. We show that the matrix elements of this force can then be expanded in a series of separable terms. The convergence of this expansion is investigated for various deformations. We observe a relatively fast convergence. This allows for a considerable reduction in computing time as compared to RHBZ calculations with the full Gogny force in the pairing channel. As an example we solve the RHBZ equations with this separable pairing force for the ground states of the chain of Sm isotopes. Good agreement with the experimental data as well as with other theoretical results is achieved.
Interactive Character Deformation Using Simplified Elastic Models
Luo, Z.
2016-01-01
This thesis describes the results of our research into realistic skin and model deformation methods aimed at the field of character deformation and animation. The main contributions lie in the properties of our deformation scheme. Our approach preserves the volume of the deformed object while
AN APPROACH TO CELL NUCLEI COUNTING IN HISTOLOGICAL IMAGE ANALYSIS
Directory of Open Access Journals (Sweden)
M. M. Lukashevich
2016-01-01
Full Text Available In the paper a method of automatical counting the number of cell nuclei in histological images is studied. This operation is commonly used in the diagnostics of various diseases and morphological analysis of cells. In this connection, the procedure of automatical count the number of cell nuclei is a key step in the systems of medical imaging microscopic analysis of histological preparations. The main aim of our work was to develop an efficient scheme of automatic counting cell nuclei based on advanced image processing methods: directional filtering, adaptive image binarization and mathematical morphology. Unlike prior research, the presented approach does not provide segmentation of cell nuclei in the image, but only requires to detect them and count their number. This avoids complex algorithmic calculations and provides good accuracy of counting cell nuclei.The paper describes a series of experiments conducted to assess the effectiveness of the proposed method using the available online database of medical test histological images. Critical parameters defined algorithms, configurable at each stage of image analysis. For each parameter we have defined value ranges, and then realized a selection of optimal values for every parameter and a mutual combination of them. It is based on generally accepted quantitative measures of precision and recall. The results were compared with the state-of-art investigations in this field and demonstrated an acceptable level of accuracy of the proposed method. The software prototype developed during the study can be regarded as an automatic tool for analysis of cell nuclei. The presented approach can be adapted to various problems of analysis of cell nuclei of various organs.
Bilateral cleft lip nasal deformity
Directory of Open Access Journals (Sweden)
Singh Arun
2009-01-01
Full Text Available Bilateral cleft lip nose deformity is a multi-factorial and complex deformity which tends to aggravate with growth of the child, if not attended surgically. The goals of primary bilateral cleft lip nose surgery are, closure of the nasal floor and sill, lengthening of the columella, repositioning of the alar base, achieving nasal tip projection, repositioning of the lower lateral cartilages, and reorienting the nares from horizontal to oblique position. The multiplicity of procedures in the literature for correction of this deformity alludes to the fact that no single procedure is entirely effective. The timing for surgical intervention and its extent varies considerably. Early surgery on cartilage may adversely affect growth and development; at the same time, allowing the cartilage to grow in an abnormal position and contributing to aggravation of deformity. Some surgeons advocate correction of deformity at an early age. However, others like the cartilages to grow and mature before going in for surgery. With peer pressure also becoming an important consideration during the teens, the current trend is towards early intervention. There is no unanimity in the extent of nasal dissection to be done at the time of primary lip repair. While many perform limited nasal dissection for the fear of growth retardation, others opt for full cartilage correction at the time of primary surgery itself. The value of naso-alveolar moulding (NAM too is not universally accepted and has now more opponents than proponents. Also most centres in the developing world have neither the personnel nor the facilities for the same. The secondary cleft nasal deformity is variable and is affected by the extent of the original abnormality, any prior surgeries performed and alteration due to nasal growth. This article reviews the currently popular methods for correction of nasal deformity associated with bilateral cleft lip, it′s management both at the time of cleft lip repair
On liquid phases in cometary nuclei
Miles, Richard; Faillace, George A.
2012-06-01
In this paper we review the relevant literature and investigate conditions likely to lead to melting of H2O ice, methanol (CH3OH) ice, ethane (C2H6) ice and other volatile ices in cometary nuclei. On the basis of a heat balance model which takes account of volatiles loss, we predict the formation of occasional aqueous and hydrocarbon liquid phases in subsurface regions at heliocentric distances, rh of 1-3 AU, and 5-12 AU, respectively. Low triple-point temperatures and low vapour pressures of C2H6, C3H8, and some higher-order alkanes and alkenes, favour liquid phase formation in cometary bodies at high rh. Microporosity and the formation of a stabilization crust occluding the escape of volatiles facilitate liquid-phase formation. Characteristics of the near-surface which favour subsurface melting include; low effective surface emissivity (at low rh), high amorphous carbon content, average pore sizes of ˜10 μm or less, presence of solutes (e.g. CH3OH), mixtures of C2-C6 hydrocarbons (for melting at high rh), diurnal thermal cycling, and slow rotation rate. Applying the principles of soil mechanics, capillary forces are shown to initiate pre-melting phenomena and subsequent melting, which is expected to impart considerable strength of ˜104 Pa in partially saturated layers, reducing porosity and permeability, enhancing thermal conductivity and heat transfer. Diurnal thermal cycling is expected to have a marked effect on the composition and distribution of H2O ice in the near-surface leading to frost heave-type phenomena even where little if any true melting occurs. Where melting does take place, capillary suction in the wetted zone has the potential to enhance heat transfer via capillary wetting in a low-gravity environment, and to modify surface topography creating relatively smooth flat-bottomed features, which have a tendency to be located within small depressions. An important aspect of the "wetted layer" model is the prediction that diurnal melt-freeze cycles
Static response of deformable microchannels
Christov, Ivan C.; Sidhore, Tanmay C.
2017-11-01
Microfluidic channels manufactured from PDMS are a key component of lab-on-a-chip devices. Experimentally, rectangular microchannels are found to deform into a non-rectangular cross-section due to fluid-structure interactions. Deformation affects the flow profile, which results in a nonlinear relationship between the volumetric flow rate and the pressure drop. We develop a framework, within the lubrication approximation (l >> w >> h), to self-consistently derive flow rate-pressure drop relations. Emphasis is placed on handling different types of elastic response: from pure plate-bending, to half-space deformation, to membrane stretching. The ``simplest'' model (Stokes flow in a 3D rectangular channel capped with a linearly elastic Kirchhoff-Love plate) agrees well with recent experiments. We also simulate the static response of such microfluidic channels under laminar flow conditions using ANSYSWorkbench. Simulations are calibrated using experimental flow rate-pressure drop data from the literature. The simulations provide highly resolved deformation profiles, which are difficult to measure experimentally. By comparing simulations, experiments and our theoretical models, we show good agreement in many flow/deformation regimes, without any fitting parameters.
Search for nuclei in heavy ion collisions at ultrarelativistic energies
2002-01-01
We would like to know if nuclei are still present after a collision of two heavy ions at ultrarelativistic energies. If one can detect some of them at large angle $(>10^{\\circ}-15^{\\circ})$ they very likely come from a multifragmentation of the excited target spectators. Such a multifragmentation in several nuclei has been in proton induced reactions at Fermilab and it was interpreted as a gas-liquid phase transition in nuclei matter near the critical point. With heavy ions the energy deposited in the target spectators will be much higher than in the case of protons and a different mechanism should be involved if nuclei are still observed. \\\\ \\\\ We propose to detect nuclei using 1-2 silicon telescopes and a 1-2mg/cm$^{2}$ Au target bombarded by an $^{16}$O or $^{32}$S beam at 226 GeV/u. The set-up will be installed in a small cube located just before the NA38 experiment and should not perturb it.\\\\ \\\\ Data from $^{16}$O incident on Au have been taken last year. The experiment is presently taking data with $^{...
Science of rare isotopes: connecting nuclei with the universe.
Nazarewicz, Witold
2008-04-01
Understanding nuclei is a quantum many-body problem of incredible richness and diversity and studies of nuclei address some of the great challenges that are common throughout modern science. Nuclear physicists strive to build a unified and comprehensive microscopic framework in which bulk nuclear properties, nuclear excitations, and nuclear reactions can all be described. A new and exciting focus in this endeavor lies in the description of short-lived nuclei. The extreme isospin of these nuclei, relative to those near stability, and their weak binding bring new phenomena to the fore which isolates and amplifies important features of nuclear many-body open quantum systems. The fields of nuclear physics and astrophysics provide the link between our understanding of the fundamental constituents of nature and explaining the matter of which we and stars are made. Studies of rare isotopes elucidate fundamental questions in this area. In this talk, experimental and theoretical advances in rare isotope research will be reviewed in the context of the main scientific questions. Particular attention will bo given to the worldwide radioactive beams initiatives and to the progress in theoretical studies of nuclei due to the advent of terascale computing platforms. Reference: Rare-Isotope Science Assessment Committee Report, The National Academies Press http://books.nap.edu/openbook.php?isbn=0309104084
Study of octupole deformation in n-rich Ba isotopes populated via $\\beta$-decay
We propose to exploit the unique capability of the ISOLDE facility to produce $^{150, 151, 152}$Cs beams to investigate their radioactive $\\beta$-decay to $^{150, 151, 152}$Ba. The interest to study this mass region is twofold: these nuclei are expected to show octupole deformations already in their low-lying state, secondly information on the $\\beta$-decay is needed for the nuclear astrophysical model. The experiment will be performed with the ISOLDE Decay Station (IDS) setup using the fast tape station of K.U.-Leuven, equipped with four Clover Germanium detectors, four LaBr$_{3}$(Ce) detectors and one LEP HPGe detector. Information on the $\\beta$-decay, such as lifetimes and delayed neutron-emission probabilities, will be extracted, together with the detailed spectroscopy of the daughter nuclei, via $\\gamma$-$\\gamma$-coincidences and lifetime measurement of specific states.
On the dynamics of fission of hot nuclei
Fröbrich, P.
2007-05-01
In this contribution I take the opportunity to address some points which are in my opinion not in a satisfactory state in the dynamical description of fission of hot nuclei. The focus is on relatively light systems where Bohr's hypothesis on the independence of the fusion and subsequent fission processes is valid, but my remarks are also of relevance to attempts to describe the complete fusion-fission process in a unified way, when quasi-fission channels compete in heavier systems and quantal effects may be of increasing importance in particular when considering low temperatures. There is no doubt that the most adequate dynamical description of the fusion-fission process is obtained by solving multi-dimensional Langevin equations to which a Monte Carlo treatment for the evaporation of light (n, p, α, γ) particles is coupled. However, there is less agreement about the input quantities which enter the description. In the review article [P. Fröbrich, I.I. Gontchar, Phys. Rep. 292, 131 (1998)], we deal mainly with an overdamped Langevin dynamics along the fission coordinate which goes over to an appropriately modified statistical model when a stationary regime with respect to the fission mode is reached. The main ingredient is a phenomenological (deformation-dependent, temperature-independent) friction force, which is invented in such a way that it allows a description of a multitude of experimental data in a universal way (i.e. with the same set of parameters). The main success was a systematic simultaneous description of fission or survival probabilities and prescission neutron multiplicities [P. Fröbrich, I.I. Gontchar, N.D. Mavlitov, Nucl. Phys. A 556, 261 (1993)]. This is not possible in any statistical model. The model describes successfully many other data for systems that develop over a completely equilibrated compound nucleus; see Ref. [P. Fröbrich, I.I. Gontchar, Phys. Rep. 292, 131 (1998)] and references therein. It deals with: fission (survival
Finite Deformation of Magnetoelastic Film
Energy Technology Data Exchange (ETDEWEB)
Barham, Matthew Ian [Univ. of California, Berkeley, CA (United States)
2011-05-31
A nonlinear two-dimensional theory is developed for thin magnetoelastic lms capable of large deformations. This is derived directly from three-dimensional theory. Signi cant simpli cations emerge in the descent from three dimensions to two, permitting the self eld generated by the body to be computed a posteriori. The model is specialized to isotropic elastomers with two material models. First weak magnetization is investigated leading to a free energy where magnetization and deformation are un-coupled. The second closely couples the magnetization and deformation. Numerical solutions are obtained to equilibrium boundary-value problems in which the membrane is subjected to lateral pressure and an applied magnetic eld. An instability is inferred and investigated for the weak magnetization material model.
Computing layouts with deformable templates
Peng, Chihan
2014-07-27
In this paper, we tackle the problem of tiling a domain with a set of deformable templates. A valid solution to this problem completely covers the domain with templates such that the templates do not overlap. We generalize existing specialized solutions and formulate a general layout problem by modeling important constraints and admissible template deformations. Our main idea is to break the layout algorithm into two steps: a discrete step to lay out the approximate template positions and a continuous step to refine the template shapes. Our approach is suitable for a large class of applications, including floorplans, urban layouts, and arts and design. Copyright © ACM.
Cavity coalescence in superplastic deformation
Energy Technology Data Exchange (ETDEWEB)
Stowell, M.J.; Livesey, D.W.; Ridley, N.
1984-01-01
An analysis of the probability distribution function of particles randomly dispersed in a solid has been applied to cavitation during superplastic deformation and a method of predicting cavity coalescence developed. Cavity size distribution data were obtained from two microduplex nickel-silver alloys deformed superplastically to various extents at elevated temperature, and compared to theoretical predictions. Excellent agreement occurred for small void sizes but the model underestimated the number of voids in the largest size groups. It is argued that the discrepancy results from a combination of effects due to non-random cavity distributions and to enhanced growth rates and incomplete spheroidization of the largest cavities.
Neutrinoless Double Beta Decay Matrix Elements in Light Nuclei
Energy Technology Data Exchange (ETDEWEB)
Pastore, S.; Carlson, J.; Cirigliano, V.; Dekens, W.; Mereghetti, E.; Wiringa, R. B.
2018-01-17
We present the first ab initio calculations of neutrinoless double-β decay matrix elements in A=6-12 nuclei using variational Monte Carlo wave functions obtained from the Argonne v_{18} two-nucleon potential and Illinois-7 three-nucleon interaction. We study both light Majorana neutrino exchange and potentials arising from a large class of multi-TeV mechanisms of lepton-number violation. Our results provide benchmarks to be used in testing many-body methods that can be extended to the heavy nuclei of experimental interest. In light nuclei we also study the impact of two-body short-range correlations and the use of different forms for the transition operators, such as those corresponding to different orders in chiral effective theory.
Generation of Transgenic Xenopus laevis: II. Sperm Nuclei Preparation.
Ishibashi, Shoko; Kroll, Kristin L; Amaya, Enrique
2007-09-01
INTRODUCTIONManipulating genes specifically during later stages of amphibian embryonic development requires fine control over the time and place of expression. These protocols describe an efficient nuclear-transplantation-based method of transgenesis developed for Xenopus laevis. The approach enables stable expression of cloned gene products in Xenopus embryos. Because the transgene integrates into the genome prior to fertilization, the resulting embryos are not chimeric, eliminating the need to breed to the next generation to obtain nonmosaic transgenic animals. The procedure is based on restriction-enzyme-mediated integration (REMI) and can be divided into three parts: (I) high-speed preparation of egg extracts, (II) sperm nuclei preparation, and (III) nuclear transplantation. This protocol describes a method for the preparation of sperm nuclei from Xenopus laevis. Sperm suspensions are prepared by filtration and centrifugation, and then treated with lysolecithin to disrupt the plasma membrane of the cells. Sperm nuclei can be stored frozen in small aliquots at -80°C.
Analyzing the spatial positioning of nuclei in polynuclear giant cells
Stange, Maike; Hintsche, Marius; Sachse, Kirsten; Gerhardt, Matthias; Valleriani, Angelo; Beta, Carsten
2017-11-01
How cells establish and maintain a well-defined size is a fundamental question of cell biology. Here we investigated to what extent the microtubule cytoskeleton can set a predefined cell size, independent of an enclosing cell membrane. We used electropulse-induced cell fusion to form giant multinuclear cells of the social amoeba Dictyostelium discoideum. Based on dual-color confocal imaging of cells that expressed fluorescent markers for the cell nucleus and the microtubules, we determined the subcellular distributions of nuclei and centrosomes in the giant cells. Our two- and three-dimensional imaging results showed that the positions of nuclei in giant cells do not fall onto a regular lattice. However, a comparison with model predictions for random positioning showed that the subcellular arrangement of nuclei maintains a low but still detectable degree of ordering. This can be explained by the steric requirements of the microtubule cytoskeleton, as confirmed by the effect of a microtubule degrading drug.
Automatic Nuclei Detection Based on Generalized Laplacian of Gaussian Filters.
Hongming Xu; Cheng Lu; Berendt, Richard; Jha, Naresh; Mandal, Mrinal
2017-05-01
Efficient and accurate detection of cell nuclei is an important step toward automatic analysis in histopathology. In this work, we present an automatic technique based on generalized Laplacian of Gaussian (gLoG) filter for nuclei detection in digitized histological images. The proposed technique first generates a bank of gLoG kernels with different scales and orientations and then performs convolution between directional gLoG kernels and the candidate image to obtain a set of response maps. The local maxima of response maps are detected and clustered into different groups by mean-shift algorithm based on their geometrical closeness. The point which has the maximum response in each group is finally selected as the nucleus seed. Experimental results on two datasets show that the proposed technique provides a superior performance in nuclei detection compared to existing techniques.
Dynamics and evolution of galactic nuclei (princeton series in astrophysics)
Merritt, David
2013-01-01
Deep within galaxies like the Milky Way, astronomers have found a fascinating legacy of Einstein's general theory of relativity: supermassive black holes. Connected to the evolution of the galaxies that contain these black holes, galactic nuclei are the sites of uniquely energetic events, including quasars, stellar tidal disruptions, and the generation of gravitational waves. This textbook is the first comprehensive introduction to dynamical processes occurring in the vicinity of supermassive black holes in their galactic environment. Filling a critical gap, it is an authoritative resource for astrophysics and physics graduate students, and researchers focusing on galactic nuclei, the astrophysics of massive black holes, galactic dynamics, and gravitational wave detection. It is an ideal text for an advanced graduate-level course on galactic nuclei and as supplementary reading in graduate-level courses on high-energy astrophysics and galactic dynamics. David Merritt summarizes the theoretical work of the las...
From light nuclei to nuclear matter the role of relativity?
Energy Technology Data Exchange (ETDEWEB)
Coester, F.; Physics
2003-11-10
The success of non-relativistic quantum dynamics in accounting for the binding energies and spectra of light nuclei with masses up to A=10 raises the question whether the same dynamics applied to infinite nuclear matter agrees with the empirical saturation properties of large nuclei. The simple unambiguous relation between few-nucleon and many-nucleon Hamiltonians is directly related to the Galilean covariance of nonrelativistic dynamics. Relations between the irreducible unitary representations of the Galilei and Poincare groups indicate that the 'nonrelativistic' nuclear Hamiltonians may provide sufficiently accurate approximations to Poincare invariant mass operators. In relativistic nuclear dynamics based on suitable Lagrangeans the intrinsic nucleon parity is an explicit, dynamically relevant, degree of freedom and the emphasis is on properties of nuclear matter. The success of this approach suggests the question how it might account for the spectral properties of light nuclei.
Fission lifetimes of Th nuclei measured by crystal blocking
Karamian, S A; Assmann, R W; Broude, C; Chevallier, J; Forster, J S; Geiger, J S; Gruener, F; Khodyrev, V A; Malaguti, F; Uguzzoni, A
2003-01-01
Crystal blocking lifetime measurements have been made for highly excited Th nuclei with neutron number well removed from the stability line. Thin W crystals were bombarded with sup 3 sup 2 S ions in the energy range 170-180 MeV and the yield of fission fragments was measured for emission close to a left angle 111 right angle axis. The fission blocking dips are compared to the appropriately scaled ones for elastic scattering of the sup 3 sup 2 S beam ions and no significant difference is seen between the dips. This implies that the fraction of nuclei fissioning with lifetimes longer than 10 as is less than 2%. Fission lifetimes are increased by viscosity in the nuclear mass flow and comparison with a statistical model calculation indicates that the viscosity parameter, eta, must be lower than for Th and U nuclei near beta-stability. The effect of the N=126 magic number is discussed. (orig.)
Particle induced nuclear reaction calculations of Boron target nuclei
Directory of Open Access Journals (Sweden)
Tel Eyyup
2017-01-01
Full Text Available Boron is usable element in many areas such as health, industry and energy. Especially, Boron neutron capture therapy (BNCT is one of the medical applications. Boron target is irradiated with low energy thermal neutrons and at the end of reactions alpha particles occur. After this process recoiling lithium-7 nuclei is composed. In this study, charge particle induced nuclear reactions calculations of Boron target nuclei were investigated in the incident proton and alpha energy range of 5–50 MeV. The excitation functions for 10B target nuclei reactions have been calculated by using PCROSS Programming code. The semi-empirical calculations for (p,α reactions have been done by using cross section formula with new coefficient obtained by Tel et al. The calculated results were compared with the experimental data from the literature.
Particle induced nuclear reaction calculations of Boron target nuclei
Tel, Eyyup; Sahan, Muhittin; Sarpün, Ismail Hakki; Kavun, Yusuf; Gök, Ali Armagan; Poyraz, Meltem
2017-09-01
Boron is usable element in many areas such as health, industry and energy. Especially, Boron neutron capture therapy (BNCT) is one of the medical applications. Boron target is irradiated with low energy thermal neutrons and at the end of reactions alpha particles occur. After this process recoiling lithium-7 nuclei is composed. In this study, charge particle induced nuclear reactions calculations of Boron target nuclei were investigated in the incident proton and alpha energy range of 5-50 MeV. The excitation functions for 10B target nuclei reactions have been calculated by using PCROSS Programming code. The semi-empirical calculations for (p,α) reactions have been done by using cross section formula with new coefficient obtained by Tel et al. The calculated results were compared with the experimental data from the literature.
Potential energy surfaces for Ж = , Ne- Ba nuclei
Indian Academy of Sciences (India)
112Ba nu- clei in an axially deformed relativistic mean field approach. A quadratic constraint scheme is applied to determine the complete energy surface for a wide range of the quadrupole deformation. The NL3, NL-RA1 and TM1 parameter sets ...
Clumpy Dust Tori in Active Galactic Nuclei
Hönig, Sebastian F.
2008-01-01
Active Galactic Nuclei (AGN) are amongst the most luminous objects in the universe. The source of their activity is accretion onto a supermassive black hole in the center of the galactic nucleus. The various phenomena observed in AGN are explained in a common unification scheme. The cornerstone of this unification scheme of AGN is the presence of an optically and geometrically thick dust torus which surrounds the central accretion disk and broad-line region (BLR). This parsec-scaled torus is responsible for the apparent difference between type 1 and type 2 AGN. If the line-of-sight intersects with the torus, the accretion disk and BLR are not visible and the AGN is classified as a type 2 object. On the other hand, if the torus is seen nearly face-on, the accretion disk and BLR are directly exposed to the observer, so that the galaxy appears as a type 1 AGN. Near- (NIR) and mid-infrared (MIR) interferometry has resolved, for the first time, the dust torus around the nearby prototypical Seyfert 2 AGN NGC 1068. These observations provided an insight into the structure of the torus: Apparently, the dust is not smoothly distributed in the torus but arranged in clumps -- contrary to what has been commonly used in models. We developed a new radiative transfer model of clumpy dust tori which is a key tool to interpret NIR and MIR observations of AGN. The model accounts for the 3-dimensional arrangement of dust clouds. Model SEDs and images can be obtained for a number of different physical parameters (e.g., radial and vertical dust density distribution, cloud radii, optical depths, etc.). It was shown that the model SEDs are in agreement with observed spectral properties. Moreover, we applied our new model to the data of NGC 1068. It was possible, for the first time, to simultaneously reproduce NIR and MIR interferometry and photometry of the nucleus of NGC 1068. In particular, the model follows the trend of the deeper 9.7 micron silicate absorption features in the
DEFF Research Database (Denmark)
Huang, X.; Borrego, A.; Pantleon, W.
2001-01-01
The relation between the polycrystal deformation and single crystal deformation has been studied for pure polycrystalline copper deformed in tension. The dislocation microstructure has been analyzed for grains of different orientation by transmission electron microscopy (TEM) and three types...
Space-based monitoring of ground deformation
Nobakht Ersi, Fereydoun; Safari, Abdolreza; Gamse, Sonja
2016-07-01
Ground deformation monitoring is valuable to understanding of the behaviour of natural phenomena. Space-Based measurement systems such as Global Positioning System are useful tools for continuous monitoring of ground deformation. Ground deformation analysis based on space geodetic techniques have provided a new, more accurate, and reliable source of information for geodetic positioning which is used to detect deformations of the Ground surface. This type of studies using displacement fields derived from repeated measurments of space-based geodetic networks indicates how crucial role the space geodetic methods play in geodynamics. The main scope of this contribution is to monitor of ground deformation by obtained measurements from GPS sites. We present ground deformation analysis in three steps: a global congruency test on daily coordinates of permanent GPS stations to specify in which epochs deformations occur, the localization of the deformed GPS sites and the determination of deformations.
Deformations of the Almheiri-Polchinski model
Energy Technology Data Exchange (ETDEWEB)
Kyono, Hideki; Okumura, Suguru; Yoshida, Kentaroh [Department of Physics, Kyoto University, Kitashirakawa Oiwake-cho, Kyoto 606-8502 (Japan)
2017-03-31
We study deformations of the Almheiri-Polchinski (AP) model by employing the Yang-Baxter deformation technique. The general deformed AdS{sub 2} metric becomes a solution of a deformed AP model. In particular, the dilaton potential is deformed from a simple quadratic form to a hyperbolic function-type potential similarly to integrable deformations. A specific solution is a deformed black hole solution. Because the deformation makes the spacetime structure around the boundary change drastically and a new naked singularity appears, the holographic interpretation is far from trivial. The Hawking temperature is the same as the undeformed case but the Bekenstein-Hawking entropy is modified due to the deformation. This entropy can also be reproduced by evaluating the renormalized stress tensor with an appropriate counter-term on the regularized screen close to the singularity.
Reactions with fast radioactive beams of neutron-rich nuclei
Energy Technology Data Exchange (ETDEWEB)
Aumann, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)
2005-11-01
The neutron dripline has presently been reached only for the lightest nuclei up to the element oxygen. In this region of light neutron-rich nuclei, scattering experiments are feasible even for dripline nuclei by utilizing high-energy secondary beams produced by fragmentation. In the present article, reactions of high-energy radioactive beams will be exemplified using recent experimental results mainly derived from measurements of breakup reactions performed at the LAND and FRS facilities at GSI and at the S800 spectrometer at the NSCL. Nuclear and electromagnetically induced reactions allow probing different aspects of nuclear structure at the limits of stability related to the neutron-proton asymmetry and the weak binding close to the dripline. Properties of the valence-neutron wave functions are studied in the one-neutron knockout reaction, revealing the changes of shell structure when going from the beta-stability line to more asymmetric loosely bound neutron-rich systems. The vanishing of the N=8 shell gap for neutron-rich systems like {sup 11}Li and {sup 12}Be, or the new closed N=14, 16 shells for the oxygen isotopes are examples. The continuum of weakly bound nuclei and halo states can be studied by inelastic scattering. The dipole response, for instance, is found to change dramatically when going away from the valley of stability. A redistribution of the dipole strength towards lower excitation energies is observed for neutron-rich nuclei, which partly might be due to a new collective excitation mode related to the neutron-proton asymmetry. Halo nuclei in particular show strong dipole transitions to the continuum at the threshold, being directly related to the ground-state properties of the projectile. Finally, an outlook on future experimental prospects is given. (orig.)
Studies of Heavy-Ion Reactions and Transuranic Nuclei
Energy Technology Data Exchange (ETDEWEB)
Schroeder, W. Udo [Univ. of Rochester, NY (United States). Dept. of Chemistry. Dept. of Physics
2016-07-28
Studies of heavy-ion reactions and transuranic nuclei performed by the University of Rochester Nuclear Science Research Group have been successful in furthering experimental systematics and theoretical understanding of the behavior of nuclear systems excited to their limits of stability. The theoretical results explain specifically the “boiling” and “vaporization” of atomic nuclei, but are more generally applicable to isolated, quantal many-particle systems which, under thermal or mechanical stresses, all disintegrate by evaporation, via surface cluster emission, or via fission-like processes. Accompanying experimental investigations by the group have demonstrated several new types of dynamical instability of nuclei: In central, “head-on” collisions, target nuclei exhibit limited ability to stop energetic projectile nuclei and to dissipate the imparted linear momentum. Substantial matter overlap (“neck”) between projectile and target nuclei, which is observed at elevated collision energies, can be stretched considerably and break at several places simultaneously. These results provide new testing grounds for microscopic theory of the cohesion of nuclear matter. This property has remained elusive, even though the elementary nucleon-nucleon forces are well known since some time. Technical R&D has resulted in a detailed characterization of a novel plastic material, which can now be used in the design of sensitive diagnostic systems for various types of radio-activity. Innovative application of powerful laser systems has produced intense, controllable sources of exotic particle radioactivity for nuclear investigations. Several students have received their Ph.D. degree in experimental nuclear science for their work on basic nuclear research or R&D projects.
Charge determination of nuclei with the AMS-02 silicon tracker
Alpat, B; Azzarello, P; Battiston, R; Bene, P; Bertucci, B; Bizzaglia, S; Bizzarri, M; Blasko, S; Bourquin, M; Bouvier, P; Burger, W J; Capell, M; Cecchi, C; Chang, Y H; Cortina, E; Dinu, N; Esposito, G; Fiandrini, E; Haas, D; Hakobyan, H; Ionica, M; Ionica, R; Kounine, A; Koutsenko, V F; Lebedev, A; Lechanoine-Leluc, C; Lin, C H; Masciocchi, F; Menichelli, M; Natale, S; Paniccia, M; Papi, A; Pauluzzi, M; Perrin, E; Pohl, M; Rapin, D; Richeux, J P; Wallraff, W; Willenbrock, M; Zuccon, P
2005-01-01
The silicon tracker of the AMS-02 detector measures the trajectory in three dimensions of electrons, protons and nuclei to high precision in a dipole magnetic field and thus measures their rigidity (momentum over charge) and the sign of their charge. In addition, it measures the specific energy loss of charged particles to determine the charge magnitude. Ladders from the AMS-02 tracker have been exposed to ion beams at CERN and GSI to study their response to nuclei from helium up to the iron group. The longest ladder, 72 multiplied by 496mm2, verified in the tests contains 12 sensors. Good charge resolution is observed up to iron.
Study on decay of rare earth nuclei produced by fission
Energy Technology Data Exchange (ETDEWEB)
Kawade, Kiyoshi; Yamamoto, Hiroshi; Shibata, Michihiro; Asai, Masato [Nagoya Univ. (Japan); Tsukada, Kazuaki; Osa, Akihiko; Shinohara, Nobuo; Iimura, Hideki
1996-01-01
JAERI-ISOL utilizes charge particle induced fission by proton and heavy proton produced by the tandem type accelerator (JAERI). To study the decay mechanism and nuclei structure of neutron and excess nuclei produced by actinoid fission, JAERI-ISOL was improved by developing the multilayer target tank. So that, the intensity of mass separated ion beam increased enough to use. New 76.6 KeV {gamma}-ray with about 10s of half life was found in the preliminary experiment. (S.Y.)
Cavitation nuclei in water exposed to transient pressures
DEFF Research Database (Denmark)
Andersen, Anders Peter; Mørch, Knud Aage
2015-01-01
A model of skin-stabilized interfacial cavitation nuclei and their response to tensile and compressive stressing is presented. The model is evaluated in relation to experimental tensile strength results for water at rest at the bottom of an open water-filled container at atmospheric pressure...... and room temperature. These results are obtained by recording the initial growth of cavities generated by a short tensile pulse applied to the bottom of the container. It is found that the cavitation nuclei shift their tensile strength depending on their pressure history. Static pressurization...
Relativistic mean field theory with the pion for finite nuclei
Energy Technology Data Exchange (ETDEWEB)
Sugimoto, S.; Toki, H.; Ikeda, K.; Minkov, N
2003-07-14
We study the possible occurrence of finite pion mean field in finite nuclei in the relativistic mean field (RMF) theory. We calculate explicitly various N = Z closed-shell nuclei with finite pion mean field in the RMF theory with the standard parameter set and the pion-nucleon coupling in free space. The finite pion mean field is introduced by breaking the parity symmetry of intrinsic single-particle states. We demonstrate the actual occurrence and the property of the finite pion mean field.
General Relativistic Mean Field Theory for rotating nuclei
Energy Technology Data Exchange (ETDEWEB)
Madokoro, Hideki [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Matsuzaki, Masayuki
1998-03-01
The {sigma}-{omega} model Lagrangian is generalized to an accelerated frame by using the technique of general relativity which is known as tetrad formalism. We apply this model to the description of rotating nuclei within the mean field approximation, which we call General Relativistic Mean Field Theory (GRMFT) for rotating nuclei. The resulting equations of motion coincide with those of Munich group whose formulation was not based on the general relativistic transformation property of the spinor fields. Some numerical results are shown for the yrast states of the Mg isotopes and the superdeformed rotational bands in the A {approx} 60 mass region. (author)
Modification of meson properties in the vicinty of nuclei
Directory of Open Access Journals (Sweden)
Filip Peter
2014-01-01
Full Text Available We suggest that modification of meson properties (lifetimes and branching ratios can occur due to the interaction of constituent quark magnetic moments with strong magnetic fields present in the close vicinity of nuclei. A superposition of (J =0 and (J =1, mz =0 particle-antiparticle quantum states (as observed for ortho-Positronium may occur also in the case of quarkonium states J/Ψ, ηc ϒ, ηb in heavy ion collisions. We speculate on possible modification of η(548 meson properties (related to C parity and CP violation in strong magnetic fields which are present in the vicinity of nuclei.
JUSTIPEN: Japan US Theory Institute for Physics with Exotic Nuclei
Energy Technology Data Exchange (ETDEWEB)
Papenbrock, Thomas
2014-05-16
The grant “JUSTIPEN: Japan US Theory Institute for Physics with Exotic Nuclei ” (DOE DE-FG02-06ER41407) ran from 02/01/2006 thru 12/31/2013. JUSTIPEN is a venue for international collaboration between U.S.-based and Japanese scientists who share an interest in theory of rare isotopes. Since its inception JUSTIPEN has supported many visitors, fostered collaborations between physicists in the U.S. and Japan, and enabled them to deepen our understanding of exotic nuclei and their role in cosmos.
Constrained caloric curves and phase transition for hot nuclei
Energy Technology Data Exchange (ETDEWEB)
Borderie, B., E-mail: borderie@ipno.in2p3.fr [Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud 11, F-91406 Orsay Cedex (France); Piantelli, S. [INFN Sezione di Firenze, 50019 Sesto Fiorentino (Italy); Rivet, M.F. [Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud 11, F-91406 Orsay Cedex (France); Raduta, Ad.R. [National Institute for Physics and Nuclear Engineering, RO-76900 Bucharest-Magurele (Romania); Ademard, G. [Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud 11, F-91406 Orsay Cedex (France); Bonnet, E. [GANIL, (DSM-CEA/CNRS-IN2P3), F-14076 Caen Cedex (France); Bougault, R. [LPC Caen, ENSICAEN, Université de Caen, CNRS-IN2P3, F-14050 Caen Cedex (France); Chbihi, A.; Frankland, J.D. [GANIL, (DSM-CEA/CNRS-IN2P3), F-14076 Caen Cedex (France); Galichet, E. [Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud 11, F-91406 Orsay Cedex (France); Conservatoire National des Arts et Métiers, F-75141 Paris Cedex 03 (France); Gruyer, D. [GANIL, (DSM-CEA/CNRS-IN2P3), F-14076 Caen Cedex (France); Guinet, D.; Lautesse, P. [Université Claude Bernard Lyon 1, Institut de Physique Nucléaire, CNRS-IN2P3, F-69622 Villeurbanne Cedex (France); Le Neindre, N.; Lopez, O. [LPC Caen, ENSICAEN, Université de Caen, CNRS-IN2P3, F-14050 Caen Cedex (France); Marini, P. [GANIL, (DSM-CEA/CNRS-IN2P3), F-14076 Caen Cedex (France); and others
2013-06-10
Simulations based on experimental data obtained from multifragmenting quasi-fused nuclei produced in central {sup 129}Xe+{sup nat}Sn collisions have been used to deduce event by event freeze-out properties in the thermal excitation energy range 4–12 AMeV [S. Piantelli, et al., INDRA Collaboration, Nucl. Phys. A 809 (2008) 111]. From these properties and the temperatures deduced from proton transverse momentum fluctuations, constrained caloric curves have been built. At constant average volumes caloric curves exhibit a monotonic behaviour whereas for constrained pressures a backbending is observed. Such results support the existence of a first order phase transition for hot nuclei.
Dissociation of relativistic 10B nuclei in nuclear track emulsion
Zaitsev, A. A.; Artemenkov, D. A.; Bradnova, V.; Zarubin, P. I.; Zarubina, I. G.; Kattabekov, R. R.; Kornegrutsa, N. K.; Mamatkulov, K. Z.; Mitsova, E. K.; Neagu, A.; Rukoyatkin, P. A.; Rusakova, V. V.; Sarkisyan, V. R.; Stanoeva, R.; Haiduc, M.; Firu, E.
2017-11-01
The structural features of 10B are studied by analyzing the dissociation of nuclei of this isotope at an energy of 1 A GeV in nuclear track emulsion. The fraction of the 10B → 2He + H channel in the charge state distribution of fragments is 78%. It was determined based on the measurements of fragment emission angles that unstable 8Beg.s. nuclei appear with a probability of (26 ± 4)%, and (14 ± 3)% of them are produced in decays of an unstable 9Bg.s. nucleus. The Be + H channel was suppressed to approximately 1%.
Nishino, H.
1977-01-01
Unit activity of lateral hypothalamic area (LHA) and Ventromedian nuclei (VMN) was recorded in urethane anesthetized male rats. A 5 to 10 sec. a 3-5 min and a circadian rhythmicity were observed. In about 15% of all neurons, spontaneous activity of LHA and VMN showed reciprocal relationships. Subthreshold stimuli applied at a slow rate in the septum and the suprachiasmatic nuclei (SCN) suppressed the rhythms without changing firing rates. On the other hand, stimulation of the optic nerve at a rate of 5 to 10/sec increased firing rates in 1/3 of neurons of SCN. Iontophoretically applied acetylcholine increased 80% of tested neurons of SCN, whereas norepinephrine, dopamine and 5 HT inhibited 64, 60 and 75% of SCN neurons respectively. These inhibitions were much stronger in neurons, the activity of which was increased by optic nerve stimulation. Stimulation of the SCN inhibited the tonic activity in cervical sympathetic nerves.
Effective liquid drop description for alpha decay of atomic nuclei
Energy Technology Data Exchange (ETDEWEB)
Tavares, O.A.P.; Duarte, S.B. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Rodriguez, O.; Guzman, F. [Instituto Superior de Ciencia y Tecnologia Nuclear (ISCTN), La Habana (Cuba); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil); Garcia, F. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica
1998-06-01
Alpha decay half-lives are presented in the framework of an effective liquid drop model for different combination of mass transfer descriptions and inertia coefficients. Calculated half-life-values for ground-state to ground-state favoured alpha transitions are compared with available, updated experimental data. Results have shown that the present model is very suitable to treat the alpha decay process on equal foot as cluster radioactivity and cold fission processes. Better agreement with the data is found when the sub-set of even-even alpha emitters are considered in the calculation. (author) 44 refs., 5 figs., 3 tabs.; e-mail: telo at ird.gov.br
CERN. Geneva
2015-01-01
is produced in the central pseudorapidity region allowing for a precise investigation of their properties. Mass and binding energy are expected to be the same in nuclei and anti-nuclei as long as the CPT invariance holds for the nuclear force, a remnant of the underlying strong interaction between quarks and gluons. The measurements of the difference in mass-to-charge ratio between deuteron and anti-deuteron, and 3He and 3\\bar{He} nuclei performed with the ALICE detector at the LHC is presented. The ALICE measurements improve by one to two orders of magnitude previous analogous direct measurements. Given the equivalence between mass and energy, the results improve by a factor two the constraints on CPT invariance inferred from measurements in the (anti-)deuteron system. The binding energy difference has been determined for the first time in the case of (anti-)3He, with a precision comparable to the one obtained in the...
Dotsenko, V.; Shadrin, S.; Vallette, B.
2016-01-01
In this paper, we develop the deformation theory controlled by pre-Lie algebras; the main tool is a new integration theory for preLie algebras. The main field of application lies in homotopy algebra structures over a Koszul operad; in this case, we provide a homotopical description of the associated
Spatiotemporal deformations of reflectionless potentials
Horsley, S. A. R.; Longhi, S.
2017-08-01
Reflectionless potentials for classical or matter waves represent an important class of scatteringless systems encountered in different areas of physics. Here we mathematically demonstrate that there is a family of non-Hermitian potentials that, in contrast to their Hermitian counterparts, remain reflectionless even when deformed in space or time. These are the profiles that satisfy the spatial Kramers-Kronig relations. We start by considering scattering of matter waves for the Schrödinger equation with an external field, where a moving potential is observed in the Kramers-Henneberger reference frame. We then generalize this result to the case of electromagnetic waves, by considering a slab of reflectionless material that both is scaled and has its center displaced as an arbitrary function of position. We analytically and numerically demonstrate that the backscattering from these profiles remains zero, even for extreme deformations. Our results indicate the supremacy of non-Hermitian Kramers-Kronig potentials over reflectionless Hermitian potentials in keeping their reflectionless property under deformation and could find applications to, e.g., reflectionless optical coatings of highly deformed surfaces based on perfect absorption.
Deformations of topological open strings
Hofman, C.; Ma, Whee Ky
Deformations of topological open string theories are described, with an emphasis on their algebraic structure. They are encoded in the mixed bulk-boundary correlators. They constitute the Hochschild complex of the open string algebra - the complex of multilinear maps on the boundary Hilbert space.
Simulation of rock deformation behavior
Directory of Open Access Journals (Sweden)
Я. И. Рудаев
2016-12-01
Full Text Available A task of simulating the deformation behavior of geomaterials under compression with account of over-extreme branch has been addressed. The physical nature of rock properties variability as initially inhomogeneous material is explained by superposition of deformation and structural transformations of evolutionary type within open nonequilibrium systems. Due to this the description of deformation and failure of rock is related to hierarchy of instabilities within the system being far from thermodynamic equilibrium. It is generally recognized, that the energy function of the current stress-strain state is a superposition of potential component and disturbance, which includes the imperfection parameter accounting for defects not only existing in the initial state, but also appearing under load. The equation of state has been obtained by minimizing the energy function by the order parameter. The imperfection parameter is expressed through the strength deterioration, which is viewed as the internal parameter of state. The evolution of strength deterioration has been studied with the help of Fokker – Planck equation, which steady form corresponds to rock statical stressing. Here the diffusion coefficient is assumed to be constant, while the function reflecting internal sliding and loosening of the geomaterials is assumed as an antigradient of elementary integration catastrophe. Thus the equation of state is supplemented with a correlation establishing relationship between parameters of imperfection and strength deterioration. While deformation process is identified with the change of dissipative media, coupled with irreversible structural fluctuations. Theoretical studies are proven with experimental data obtained by subjecting certain rock specimens to compression.
Deformable Models for Eye Tracking
DEFF Research Database (Denmark)
Vester-Christensen, Martin; Leimberg, Denis; Ersbøll, Bjarne Kjær
2005-01-01
A deformable template method for eye tracking on full face images is presented. The strengths of the method are that it is fast and retains accuracy independently of the resolution. We compare the me\\$\\backslash\\$-thod with a state of the art active contour approach, showing that the heuristic...
Deformation mechanisms of nanotwinned Al
Energy Technology Data Exchange (ETDEWEB)
Zhang, Xinghang [Texas A & M Univ., College Station, TX (United States)
2016-11-10
The objective of this project is to investigate the role of different types of layer interfaces on the formation of high density stacking fault (SF) in Al in Al/fcc multilayers, and understand the corresponding deformation mechanisms of the films. Stacking faults or twins can be intentionally introduced (via growth) into certain fcc metals with low stacking fault energy (such as Cu, Ag and 330 stainless steels) to achieve high strength, high ductility, superior thermal stability and good electrical conductivity. However it is still a major challenge to synthesize these types of defects into metals with high stacking fault energy, such as Al. Although deformation twins have been observed in some nanocrystalline Al powders by low temperature, high strain rate cryomilling or in Al at the edge of crack tip or indentation (with the assistance of high stress intensity factor), these deformation techniques typically introduce twins sporadically and the control of deformation twin density in Al is still not feasible. This project is designed to test the following hypotheses: (1) Certain type of layer interfaces may assist the formation of SF in Al, (2) Al with high density SF may have deformation mechanisms drastically different from those of coarse-grained Al and nanotwinned Cu. To test these hypotheses, we have performed the following tasks: (i) Investigate the influence of layer interfaces, stresses and deposition parameters on the formation and density of SF in Al. (ii) Understand the role of SF on the deformation behavior of Al. In situ nanoindentation experiments will be performed to probe deformation mechanisms in Al. The major findings related to the formation mechanism of twins and mechanical behavior of nanotwinned metals include the followings: 1) Our studies show that nanotwins can be introduced into metals with high stacking fault energy, in drastic contrast to the general anticipation. 2) We show two strategies that can effectively introduce growth twins in
Treatment of hallux valgus deformity.
Fraissler, Lukas; Konrads, Christian; Hoberg, Maik; Rudert, Maximilian; Walcher, Matthias
2016-08-01
Hallux valgus deformity is a very common pathological condition which commonly produces painful disability. It is characterised as a combined deformity with a malpositioning of the first metatarsophalangeal joint caused by a lateral deviation of the great toe and a medial deviation of the first metatarsal bone.Taking the patient's history and a thorough physical examination are important steps. Anteroposterior and lateral weight-bearing radiographs of the entire foot are crucial for adequate assessment in the treatment of hallux valgus.Non-operative treatment of the hallux valgus cannot correct the deformity. However, insoles and physiotherapy in combination with good footwear can help to control the symptoms.There are many operative techniques for hallux valgus correction. The decision on which surgical technique is used depends on the degree of deformity, the extent of degenerative changes of the first metatarsophalangeal joint and the shape and size of the metatarsal bone and phalangeal deviation. The role of stability of the first tarsometatarsal joint is controversial.Surgical techniques include the modified McBride procedure, distal metatarsal osteotomies, metatarsal shaft osteotomies, the Akin osteotomy, proximal metatarsal osteotomies, the modified Lapidus fusion and the hallux joint fusion. Recently, minimally invasive percutaneous techniques have gained importance and are currently being evaluated more scientifically.Hallux valgus correction is followed by corrective dressings of the great toe post-operatively. Depending on the procedure, partial or full weight-bearing in a post-operative shoe or cast immobilisation is advised. Post-operative radiographs are taken in regular intervals until osseous healing is achieved. Cite this article: Fraissler L, Konrads C, Hoberg M, Rudert M, Walcher M. Treatment of hallux valgus deformity. EFORT Open Rev 2016;1:295-302. DOI: 10.1302/2058-5241.1.000005.
Thermostability of sperm nuclei assessed by microinjection into hamster oocytes
Nuclei isolated from spermatozoa of various species (golden hamster, mouse, human, rooster, and the fish tilapia) were heated at 60 degrees-125 degrees C for 20-120 min and then microinjected into hamster oocytes to determine whether they could decondense and develop into pronucl...
Structure of light neutron-rich nuclei through Coulomb dissociation
Indian Academy of Sciences (India)
pp. 535–544. Structure of light neutron-rich nuclei through Coulomb dissociation. U DATTA PRAMANIK, T AUMANN, D CORTINA, H EMLING, H GEISSEL, M HELL-. STR ¨OM, R HOLZMANN, N IWASA, Y LEIFELS, G M ¨UNZENBERG, M REJMUND,. C SCHEIDENBERGER, K S ¨UMMERER, A LEISTENSCHNEIDER. ½.
A microscopic multiphonon approach to even and odd nuclei
Czech Academy of Sciences Publication Activity Database
De Gregorio, G.; Knapp, F.; Lo Iudice, N.; Veselý, Petr
2017-01-01
Roč. 92, č. 7 (2017), č. článku 074003. ISSN 0031-8949 R&D Projects: GA ČR GA13-07117S Institutional support: RVO:61389005 Keywords : E1 response in nuclei * nuclear many- body theory * nuclear structure Subject RIV: BE - Theoretical Physics Impact factor: 1.280, year: 2016
On the Formation Mechanism of the Atomcule of Light Nuclei
Dineykhan, M D; Sakhyev, S K
2002-01-01
In the framework of the oscillator representation method the interaction potential between the antiproton and the nucleus is analytically derived. This potential is antisymmetrical with respect to the charge and masses of the constituent particles. It is shown that the antisymmetry of the potential determines the stability of the atomcule of light nuclei.
Low lying collective 2/sup +/ states of spherical nuclei
Energy Technology Data Exchange (ETDEWEB)
Khodel, V.A.
1976-02-01
The nature of low-lying collective 2/sup +/ states of superfluid spherical nuclei is investigated. It is shown that the dominating role in formation of these excitations is played by effective attraction between the quasiparticles of the last unfilled shell, arising from exchange by quantal capillar waves--capons.
Quantitative 3-D texture analysis of interphase cell nuclei
Strasters, K.C.; Smeulders, A.W.M.; van der Voort, H.T.M.; Young, I.T.; Nanninga, N.; Young, I.T.
1992-01-01
In order to investigate the spatio-temporal structure of chromatin in interphase nuclei the authors present two 3-D texture parameters based on the grey-weighted distance transform that quantify the accessibility and the homogeneity of a nucleus. Results of experiments on computer generated textures
The dipole response of nuclei with large neutron excess
Energy Technology Data Exchange (ETDEWEB)
Aumann, T. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Boretzky, K.; Cortina, D.; Datta Pramanik, U.; Elze, T.W.; Emling, H.; Geissel, H.; Gruenschloss, A.; Hellstroem, M.; Ilievski, S.; Iwasa, N.; Kratz, J.V.; Kulessa, R.; Leifels, Y.; Leistenschneider, A.; Lubkiewicz, E.; Muenzenberg, G.; Reiter, P.; Scheidenberger, C.; Schlegel, C.; Simon, H.; Suemmerer, K.; Wajda, E.; Walus, W.
2003-07-01
The dipole response of neutron-rich nuclei in the mass range from A=10 to A=22 and with mass to charge ratios of 2.5 to 2.8 has been investigated experimentally utilizing electromagnetic excitation in heavy-ion collisions at beam energies around 600 MeV/u. (orig.)
Nuclear pore ion channel activity in live syncytial nuclei.
Bustamante, Jose Omar
2002-05-01
Nuclear pore complexes (NPCs) are important nanochannels for the control of gene activity and expression. Most of our knowledge of NPC function has been derived from isolated nuclei and permeabilized cells in cell lysates/extracts. Since recent patch-clamp work has challenged the dogma that NPCs are freely permeable to small particles, a preparation of isolated living nuclei in their native liquid environment was sought and found: the syncytial nuclei in the water of the coconut Cocos nucifera. These nuclei have all properties of NPC-mediated macromolecular transport (MMT) and express foreign green fluorescent protein (GFP) plasmids. They display chromatin movement, are created by particle aggregation or by division, can grow by throwing filaments to catch material, etc. This study shows, for the first time, that living NPCs engaged in MMT do not transport physiological ions - a phenomenon that explains observations of nucleocytoplasmic ion gradients. Since coconuts are inexpensive (less than US$1/nut per litre), this robust preparation may contribute to our understanding of NPCs and cell nucleus and to the development of biotechnologies for the production of DNA, RNA and proteins.
Multiple quantum spin counting techniques with quadrupolar nuclei
Dodd, A.J.; Eck, E.R.H. van
2004-01-01
Phase incremented and continuous irradiation multiple spin correlation methods are applied to spin 3/2 nuclei with small quadrupole couplings such as Li-7 in LiCl and are shown to successfully produce a coherently coupled dipolar spin network. Application to the analogous Na salt shows successful
P CYGNI PROFILES OF MOLECULAR LINES TOWARD ARP 220 NUCLEI
Sakamoto, Kazushi; Aalto, Susanne; Wilner, David J.; Black, John H.; Conway, John E.; Costagliola, Francesco; Peck, Alison B.; Spaans, Marco; Wang, Junzhi; Wiedner, Martina C.
2009-01-01
We report similar to 100 pc (0 ''.3) resolution observations of (sub) millimeter HCO(+) and CO lines in the ultraluminous infrared galaxy Arp 220. The lines peak at two merger nuclei, with HCO(+) being more spatially concentrated than CO. Asymmetric line profiles with blueshifted absorption and
Time Delay Evolution of Five Active Galactic Nuclei
Indian Academy of Sciences (India)
Home; Journals; Journal of Astrophysics and Astronomy; Volume 36; Issue 4. Time Delay Evolution of Five ... Here we investigate light curves of the continuum and emission lines of five type 1 active galactic nuclei (AGN) from our monitoring campaign, to test time-evolution of their time delays. Using both modeled and ...
Haloes and clustering in light, neutron-rich nuclei
Energy Technology Data Exchange (ETDEWEB)
Orr, N.A
2001-10-01
Clustering is a relatively widespread phenomenon which takes on many guises across the nuclear landscape. Selected topics concerning the study of halo systems and clustering in light, neutron-rich nuclei are discussed here through illustrative examples taken from the Be isotopic chain. (author)
Level density and shape changes in excited sd shell nuclei
Indian Academy of Sciences (India)
Its applications in the study of fast rotating nuclei [7,8] are .... The particles, neutrons/protons are allowed to fill up the states in a random fashion. Suppose in the Kth configuration if niK is the single particle occupation probability ... due to the availability of fast computers, we were able to present the usefulness of our method ...
Cerebellar Deep Nuclei Involvement in Cognitive Adaptation and Automaticity
Callu, Delphine; Lopez, Joelle; El Massioui, Nicole
2013-01-01
To determine the role of the interpositus nuclei of cerebellum in rule-based learning and optimization processes, we studied (1) successive transfers of an initially acquired response rule in a cross maze and (2) behavioral strategies in learning a simple response rule in a T maze in interpositus lesioned rats (neurotoxic or electrolytic lesions).…
Color molecular dynamics for dense matter and nuclei
Energy Technology Data Exchange (ETDEWEB)
Maruyama, Toshiki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Hatsuda, T. [Kyoto Univ. (Japan). Faculty of Science
2000-01-01
We propose a microscopic simulation for quark many-body system based on a molecular dynamics. Using confinement potential, one-gluon exchange potential and meson exchange potentials, we can construct color-singlet nucleons, nuclei and also an infinite nuclear/quark matter. Statistical feature and the dynamical change between confinement and deconfinement phases are studied with this molecular dynamics simulation. (author)
Borromean halo, Tango halo, and halo isomers in atomic nuclei
Izosimov, Igor
2016-01-01
Structure of the ground and excited states in halo-like nuclei is discussed. Both the Borromean and tango halo types can be observed for n-p configurations of atomic nuclei.Structure of the halo may be different for the different levels and resonances in atomic nuclei. Isobar analog, double isobar analog, configuration, and double configuration states can simultaneously have n-n, n-p, and p-p halo components in their wave functions. When the halo structure of the excited state differs from that of the ground state, or the ground state has non-halo structure, the γ-transition from the excited state to the ground state can be essentially hindered, i.e. the formation of a specific type of isomers (halo isomers) becomes possible. B(Mγ) and B(Eγ) values for γ-transitions in 6,7,8Li, 8,9,10Be, 8,10,11B, 10,11,12,13,14C, 13,14,15,16,17N, 15,16,17,19O, and 17F are analyzed. Special attention is given to nuclei which ground state does not exhibit halo structure but the excited state (halo isomer) may have one.
Three-particle decays of light-nuclei resonances
DEFF Research Database (Denmark)
Álvarez-Rodríguez, R.; Jensen, A.S.; Garrido, E.
2012-01-01
We have studied the three-particle decay of 12C, 9Be and 6Be resonances. These nuclei have been described as three-body systems by means of the complex scaled hyperspherical adiabatic expansion method. The short-distance part of the wave function is responsible for the energies, whereas the infor...
COMPRESSIBILITY OF NUCLEI IN RELATIVISTIC MEAN FIELD-THEORY
BOERSMA, HF; MALFLIET, R; SCHOLTEN, O
1991-01-01
Using the relativistic Hartree approximation in the sigma-omega model we study the isoscalar giant monopole resonance. It is shown that the ISGMR of lighter nuclei has non-negligible anharmonic terms. The compressibility of nuclear matter is determined using a leptodermous expansion.
The Radius-Luminosity Relationship for Active Galactic Nuclei
DEFF Research Database (Denmark)
Bentz, Misty C.; Peterson, Bradley M.; Pogge, Richard W.
2006-01-01
We have obtained high resolution images of the central regions of 14 reverberation-mapped active galactic nuclei (AGN) using the Hubble Space Telescope Advanced Camera for Surveys High Resolution Camera to account for host-galaxy starlight contamination of measured AGN luminosities. We measure th...
Gamma-ray bursts, galactic nuclei and cosmic evolution
Rees, Martin J.
2014-12-01
This lecture summarises some aspects of gamma-ray bursts, a topic to which Bohdan Paczyński made crucial contributions. It then, more briefly, comments on quasars and active galactic nuclei, where the accretion processes studied by Paczyński and his Polish colleagues play a key role. The lecture concludes with some remarks on cosmology and cosmic evolution.
The symmetry energy in nuclei and in nuclear matter
Dieperink, A. E. L.; Van Isacker, P.
We discuss to what extent information on ground-state properties of finite nuclei ( energies and radii) can be used to obtain constraints on the symmetry energy in nuclear matter and its dependence on the density. The starting point is a generalized Weizsacker formula for ground-state energies. In
The symmetry energy in nuclei and in nuclear matter
Van Isacker, P.; Dieperink, A. E. L.
2006-01-01
We discuss to what extent information on ground-state properties of finite nuclei (energies and radii) can be used to obtain constraints on the symmetry energy in nuclear matter and its dependence on the density. The starting point is a generalized Weizsacker formula for ground-state energies. In
Connections of the vestibular nuclei in the rabbit
A.H. Epema
1990-01-01
textabstractThis thesis descnbes the afferent, efferent and intrinsic connections of the vestibular nuclei in the Dutch belted rabbit. Different anatomical tracing techniques were used to study these projections. A description of the vestibular complex was added, since recent data for the rabbit
The interaction between feedback from active galactic nuclei and supernovae
Booth, C.M.; Schaye, J.
2013-01-01
Energetic feedback from supernovae (SNe) and from active galactic nuclei (AGN) are both important processes that are thought to control how much gas is able to condense into galaxies and form stars. We show that although both AGN and SNe suppress star formation, they mutually weaken one another's
Symmetry remnants in the face of competing interactions in nuclei
Energy Technology Data Exchange (ETDEWEB)
Leviatan, A., E-mail: ami@phys.huji.ac.il [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Macek, M., E-mail: michal.macek@yale.edu [Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, CT 06520-8120 (United States)
2015-10-15
Detailed description of nuclei necessitates model Hamiltonians which break most dynamical symmetries. Nevertheless, generalized notions of partial and quasi dynamical symmetries may still be applicable to selected subsets of states, amidst a complicated environment of other states. We examine such scenarios in the context of nuclear shape-phase transitions.
Recent studies of heavy nuclei far from stability at JYFL
Energy Technology Data Exchange (ETDEWEB)
Julin, R.; Enqvist, T.; Helariutta, K. [Univ. of Jyvaeskylae (Finland)] [and others
1996-12-31
The new K=130 Cyclotron + ECR facility of the Physics Department of the University of Jyvaskyla (JYFL) provides stable beams from protons up to krypton ions for nuclear structure studies. Two instruments designed especially for in-beam spectroscopic studies of heavy nuclei at JYFL are introduced in this contribution. Some results from recent measurements with them are reported.
Nuclear shell effect and collinear tripartition of nuclei
Indian Academy of Sciences (India)
2015-08-04
Aug 4, 2015 ... The potential energy surface (PES) for the ternary system forming a collinear nuclear chain is calculated for a wide range of masses and charge num- bers of the constituent nuclei. The results of the PES for the tripartition of 252Cf(sf, fff) allows us to establish dynamical conditions leading to the formation of ...
Rare βp decays in light nuclei
DEFF Research Database (Denmark)
Borge, M.J.G.; Fraile, L.M.; Fynbo, Hans Otto Uldall
2013-01-01
Beta-delayed proton emission may occur at very low rates in the decays of the light nuclei 11Be and 8B. This paper explores the potential physical significance of such decays, estimates their rates and reports on first attempts to detect them: an experiment at ISOLDE/CERN gives a branching ratio ...
The structure of the dusty cores of active galactic nuclei
López Gonzaga, Noel
2016-01-01
Active galactic nuclei (AGN) have been extensively studied to understand the possible link between the growth of super-massive black holes (SMBHs) and the evolution of galaxies. Circumnuclear dust present in AGNs plays a major role in the unification theory of AGNs. The X-ray/Optical/UV light from
Prediction of deformity in spinal tuberculosis
Jutte, Paul; Wuite, Sander; The, Bertram; van Altena, Richard; Veldhuizen, Albert
Tuberculosis of the spine may cause kyphosis, which may in turn cause late paraplegia, respiratory compromise, and unsightly deformity. Surgical correction therefore may be considered for large or progressive deformities. We retrospectively analyzed clinical and radiographic parameters to predict
Dobaczewski, J.; Olbratowski, P.
2005-05-01
-range interaction, allows for a simple implementation of pairing effects within the Hartree-Fock-Bogolyubov method. Solution method: The program uses the Cartesian harmonic-oscillator basis to expand single-particle or single-quasiparticle wave functions of neutrons and protons interacting by means of the Skyrme effective interaction and zero-range pairing interaction. The expansion coefficients are determined by the iterative diagonalization of the mean field Hamiltonians or Routhians which depend non-linearly on the local neutron and proton densities. Suitable constrains are used to obtain states corresponding to a given configuration, deformation or angular momentum. The method of solution has been presented in [J. Dobaczewski, J. Dudek, Comput. Phys. Comm. 102 (1997) 166]. Summary of revisions: 1. Incorrect value of the " t" force parameter for SLY5 has been corrected. 2. Opening of an empty file "FILREC" for IWRIRE=-1 has been removed. 3. Call to subroutine "OLSTOR" has been moved before that to "SPZERO". In this way, correct data transferred to "FLISIG", "FLISIM", "FLISIQ" or "FLISIZ" allow for a correct determination of the candidate states for diabatic blocking. These corrections pertain to the user interface of the code and do not affect results performed for forces other than SLY5. Restrictions on the complexity of the problem: The main restriction is the CPU time required for calculations of heavy deformed nuclei and for a given precision required. Pairing correlations are only included for even-even nuclei and conserved simplex symmetry. Unusual features: The user must have access to the NAGLIB subroutine F02AXE or to the LAPACK subroutines ZHPEV or ZHPEVX, which diagonalize complex Hermitian matrices, or provide another subroutine which can perform such a task. The LAPACK subroutines ZHPEV and ZHPEVX can be obtained from the Netlib Repository at University of Tennessee, Knoxville: http://netlib2.cs.utk.edu/cgi-bin/netlibfiles.pl?filename=/lapack/complex16/zhpev.f and
Three-body halo nuclei in an effective theory framework
Energy Technology Data Exchange (ETDEWEB)
Canham, David L.
2009-05-20
The universal properties and structure of halo nuclei composed of two neutrons (2n) and a core are investigated within an effective quantum mechanics framework. We construct an effective interaction potential that exploits the separation of scales in halo nuclei and treat the nucleus as an effective three-body system, which to leading order is described by the large S-wave scattering lengths in the underlying two-body subsystems. The uncertainty from higher orders in the expansion is quantified through theoretical error bands. First, we investigate the possibility to observe excited Efimov states in 2n halo nuclei. Based on the experimental data, {sup 20}C is the only halo nucleus candidate to possibly have an Efimov excited state, with an energy less than 7 keV below the scattering threshold. Second, we study the structure of {sup 20}C and other 2n halo nuclei. In particular, we calculate their matter density form factors, radii, and two-neutron opening angles. We then make a systematic improvement upon these calculations by extending the effective potential to the next-to-leading order. To this order, we require an additional two-body parameter, which we tune to the effective range of the interaction. In addition to range corrections to the 2n halo nuclei results, we show corrections to the Efimov effect in the three-boson system. Furthermore, we explore universality in the linear range corrections to the Efimov spectrum. Finally, we study the scattering of D{sup 0} and D{sup *0} mesons and their antiparticles off the X(3872) in an effective field theory for short-range interactions. We present results for the S-wave scattering amplitude, total interaction cross section and S-wave scattering length. (orig.)
Dynamic-angle spinning and double rotation of quadrupolar nuclei
Energy Technology Data Exchange (ETDEWEB)
Mueller, K.T. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Chemistry)
1991-07-01
Nuclear magnetic resonance (NMR) spectroscopy of quadrupolar nuclei is complicated by the coupling of the electric quadrupole moment of the nucleus to local variations in the electric field. The quadrupolar interaction is a useful source of information about local molecular structure in solids, but it tends to broaden resonance lines causing crowding and overlap in NMR spectra. Magic- angle spinning, which is routinely used to produce high resolution spectra of spin-{1/2} nuclei like carbon-13 and silicon-29, is incapable of fully narrowing resonances from quadrupolar nuclei when anisotropic second-order quadrupolar interactions are present. Two new sample-spinning techniques are introduced here that completely average the second-order quadrupolar coupling. Narrow resonance lines are obtained and individual resonances from distinct nuclear sites are identified. In dynamic-angle spinning (DAS) a rotor containing a powdered sample is reoriented between discrete angles with respect to high magnetic field. Evolution under anisotropic interactions at the different angles cancels, leaving only the isotropic evolution of the spin system. In the second technique, double rotation (DOR), a small rotor spins within a larger rotor so that the sample traces out a complicated trajectory in space. The relative orientation of the rotors and the orientation of the larger rotor within the magnetic field are selected to average both first- and second-order anisotropic broadening. The theory of quadrupolar interactions, coherent averaging theory, and motional narrowing by sample reorientation are reviewed with emphasis on the chemical shift anisotropy and second-order quadrupolar interactions experienced by half-odd integer spin quadrupolar nuclei. The DAS and DOR techniques are introduced and illustrated with application to common quadrupolar systems such as sodium-23 and oxygen-17 nuclei in solids.
Tuberous breast deformity: principles and practice.
Meara, J G; Kolker, A; Bartlett, G; Theile, R; Mutimer, K; Holmes, A D
2000-12-01
The tuberous breast deformity is one of the most challenging congenital breast anomalies. The nomenclature, classification, and treatment of this pathological condition have varied considerably. In this study, 16 patients with 23 tuberous breast deformities are evaluated. The breast deformities are classified according to the three-tier classification system used at the authors' institution. The treatment pattern is evaluated and a flexible algorithm is discussed for the treatment of the tuberous breast deformity.
An image processing pipeline to detect and segment nuclei in muscle fiber microscopic images.
Guo, Yanen; Xu, Xiaoyin; Wang, Yuanyuan; Wang, Yaming; Xia, Shunren; Yang, Zhong
2014-08-01
Muscle fiber images play an important role in the medical diagnosis and treatment of many muscular diseases. The number of nuclei in skeletal muscle fiber images is a key bio-marker of the diagnosis of muscular dystrophy. In nuclei segmentation one primary challenge is to correctly separate the clustered nuclei. In this article, we developed an image processing pipeline to automatically detect, segment, and analyze nuclei in microscopic image of muscle fibers. The pipeline consists of image pre-processing, identification of isolated nuclei, identification and segmentation of clustered nuclei, and quantitative analysis. Nuclei are initially extracted from background by using local Otsu's threshold. Based on analysis of morphological features of the isolated nuclei, including their areas, compactness, and major axis lengths, a Bayesian network is trained and applied to identify isolated nuclei from clustered nuclei and artifacts in all the images. Then a two-step refined watershed algorithm is applied to segment clustered nuclei. After segmentation, the nuclei can be quantified for statistical analysis. Comparing the segmented results with those of manual analysis and an existing technique, we find that our proposed image processing pipeline achieves good performance with high accuracy and precision. The presented image processing pipeline can therefore help biologists increase their throughput and objectivity in analyzing large numbers of nuclei in muscle fiber images. © 2014 Wiley Periodicals, Inc.
Directory of Open Access Journals (Sweden)
Poltoratska I.
2012-12-01
Full Text Available A high resolution proton scattering experiment has been performed on the heavy deformed nucleus 154Sm at extreme forward angles with 300 MeV polarized protons at RCNP, Osaka. Our scientific goal is to investigate the impact of ground state deformation on the properties of the pygmy dipole resonance and on the spin-M1 resonance showing a double-humped structure in heavy deformed nuclei. The (p, p′ cross sections can be decomposed into E1 and M1 parts in two independent ways based either on a multipole decomposition of the cross sections or on spin-transfer observables as has been demonstrated for the case of 208Pb. We present the method and preliminary results from the analysis of polarization transfer observables.
Low-energy structure studies of odd-odd deformed nuclei and the coriolis and residual interactions
Energy Technology Data Exchange (ETDEWEB)
Dewberry, R.A.
1980-08-01
The nuclear level structure of /sup 176/Lu, /sup 170/Tm, /sup 166/Ho, and /sup 160/Tb have been studied by means of the /sup 177/Hf(t,..cap alpha..)/sup 176/Lu, /sup 171/Yb(t,..cap alpha..)/sup 170/Tm, /sup 167/Er(t,..cap alpha..)/sup 166/Ho, and /sup 161/Dy(t,..cap alpha..)/sup 160/Tb reactions and with the use of previously published (d,p) spectroscopy and gamma transitions from the (n,..gamma..) reactions. The (t,..cap alpha..) reactions have been performed and analyzed with 17 MeV tritons and the Los Alamos Q3D spectrometer. Eighty-one new rotational states in excited proton configurations or vibrational excited states are proposed. An independent parameterization of the Coriolis interaction is presented, which leads to satisfactory results in reproducing experimental single-particle transfer reaction cross-sections by theoretical calculations. The anomalous population of the excited neutron configurations (404 reduces to -624 up arrow) in /sup 176/Lu and (411 reduces to +- 512 up arrow) in /sup 170/Tm, and the anomalously low (t,..cap alpha..) cross-sections of the (411 up arrow +- 633 up arrow) configuration in /sup 166/Ho are observed. Qualitative explanation of the anomalies is presented in terms of the mixing of states which satisfy the requirement delta/sub I'/,/sub I/delta/sub K'/,/sub K/. Off-diagonal H/sub INT/ matrix elements are calculated, which show that the residual interaction cannot be used to account for the magnitude of the cross-sections observed.
Energy Technology Data Exchange (ETDEWEB)
Alimohammadi, M.; Hassanabadi, H. [Shahrood University of Technology, Physics Department, Shahrood (Iran, Islamic Republic of)
2017-06-15
In this paper, we present a model which is composed of two parts related to the special critical points, E(5) (the phase transition between spherical oscillator and γ-soft) and X(3) (a γ-rigid version of X(5)). This model is studied to investigate the interplay situations by the free parameter χ. These situations are cited between the γ-unstable and γ-rigid version of the Bohr Hamiltonian. The corresponding wave equation has been considered and the eigenvalues as well as eigenfunctions have been determined by solving this equation. Moreover, we have calculated the energy spectra and transition rates in order to compare our results with experimental data. (orig.)
Criterion for surface contact deformation of metals
Jamari, Jamari; Schipper, Dirk J.
2007-01-01
In most engineering applications, bulk plastic deformation of the surface is avoided. There is, however, no criterion for determining whether or not bulk plastic deformation occurs during the contact between rough surfaces. This paper presents a criterion for predicting the deformation behaviour of
Covariant Deformation Quantization of Free Fields
Harrivel, Dikanaina
2006-01-01
We define covariantly a deformation of a given algebra, then we will see how it can be related to a deformation quantization of a class of observables in Quantum Field Theory. Then we will investigate the operator order related to this deformation quantization.
Protein transfer to membranes upon shape deformation
Sagis, L.M.C.; Bijl, E.; Antono, L.; Ruijter, de N.C.A.; Valenberg, van H.J.F.
2013-01-01
Red blood cells, milk fat droplets, or liposomes all have interfaces consisting of lipid membranes. These particles show significant shape deformations as a result of flow. Here we show that these shape deformations can induce adsorption of proteins to the membrane. Red blood cell deformability is
7 CFR 51.1357 - Seriously deformed.
2010-01-01
... were well formed. Round or apple-shaped pears shall not be considered seriously deformed. ... STANDARDS) United States Standards for Pears for Canning Definitions § 51.1357 Seriously deformed. Seriously deformed means that the pear is so badly misshapen as to cause a loss during the usual commercial...
Molecular deformation mechanisms in polyethylene
Coutry, S
2001-01-01
adjacent labelled stems is significantly larger when the DPE guest is a copolymer molecule. Our comparative studies on various types of polyethylene lead to the conclusion that their deformation behaviour under drawing has the same basis, with additional effects imputed to the presence of tie-molecules and branches. Three major points were identified in this thesis. The changes produced by drawing imply (1) the crystallisation of some of the amorphous polymer and the subsequent orientation of the newly formed crystals, (2) the re-orientation of the crystalline ribbons and (3) the beginning of crystallite break-up. However, additional effects were observed for the high molecular weight linear sample and the copolymer sample and were attributed, respectively, to the presence of tie-molecules and of branches. It was concluded that both the tie-molecules and the branches are restricting the molecular movement during deformation, and that the branches may be acting as 'anchors'. This work is concerned with details...
Deformation models for image recognition.
Keysers, Daniel; Deselaers, Thomas; Gollan, Christian; Ney, Hermann
2007-08-01
We present the application of different nonlinear image deformation models to the task of image recognition. The deformation models are especially suited for local changes as they often occur in the presence of image object variability. We show that, among the discussed models, there is one approach that combines simplicity of implementation, low-computational complexity, and highly competitive performance across various real-world image recognition tasks. We show experimentally that the model performs very well for four different handwritten digit recognition tasks and for the classification of medical images, thus showing high generalization capacity. In particular, an error rate of 0.54 percent on the MNIST benchmark is achieved, as well as the lowest reported error rate, specifically 12.6 percent, in the 2005 international ImageCLEF evaluation of medical image categorization.
Variational approach and deformed derivatives
Weberszpil, J.; Helayël-Neto, J. A.
2016-05-01
Recently, we have demonstrated that there exists a possible relationship between q-deformed algebras in two different contexts of Statistical Mechanics, namely, the Tsallis' framework and the Kaniadakis' scenario, with a local form of fractional-derivative operators for fractal media, the so-called Hausdorff derivatives, mapped into a continuous medium with a fractal measure. Here, in this paper, we present an extension of the traditional calculus of variations for systems containing deformed-derivatives embedded into the Lagrangian and the Lagrangian densities for classical and field systems. The results extend the classical Euler-Lagrange equations and the Hamiltonian formalism. The resulting dynamical equations seem to be compatible with those found in the literature, specially with mass-dependent and with nonlinear equations for systems in classical and quantum mechanics. Examples are presented to illustrate applications of the formulation. Also, the conserved Noether current is worked out.
Hindfoot Arthrodesis for Neuropathic Deformity
Directory of Open Access Journals (Sweden)
Peng-Ju Huang
2007-03-01
Full Text Available Acquired neurologic disorders of the foot lead to arthrosis, deformities, instabilities, and functional disabilities. Hindfoot arthrodesis is the current option available for irreducible or nonbraceable deformities of neuropathic feet. However, the role of ankle arthrodesis in these patients has been questioned because of high nonunion and complication rates. From 1990 to 2001, 17 cases of acquired neuropathic foot deformities were treated by four tibiotalocalcaneal (TTC arthrodeses and 13 ankle arthrodeses. TTC arthrodesis was performed on cases with combined ankle and subtalar arthritis or cases whose deformities or instabilities could not be corrected by ankle fusion alone. There was no nonunion of TTC arthrodesis and seven ununited ankle arthrodeses were salvaged by two TTC-attempted arthrodeses and five revision ankle-attempted arthrodeses. Eventually in these cases, there was one nonunion in TTC arthrodesis and one nonunion in revision ankle arthrodesis. The final fusion rate was 88% (15 of 17 cases with average union time of 6.9 months (range, 2.5–18 months. The American Orthopaedic Foot and Ankle Society ankle hind-foot functional scores were evaluated: one was excellent (5.8%, seven were good (41%, eight were fair (53.3%, and one was poor (5.8% in terms of total functional outcome. We conclude that TTC arthrodesis is indicated for cases with ankle and subtalar involvement and ankle arthrodesis is an alternative for cases with intact subtalar joint. We recommend revision ankle arthrodesis if the ankle fails to fuse and the bone stock of the talus is adequate. TTC arthrodesis is reserved for ankles with poor bone stock of the talus with fragmentation.
Indian Academy of Sciences (India)
Similar features, namely reverse bifurcations in ϵ-space, and the co-existence of the fixed point x* = 0 with other dynamical behaviour at high ϵ, are observed for larger values of a as well (see figures 4–7). So the chaotic logistic map under deformation with positive ϵ can yield stable fixed points. For instance: (i) For a = 3.6 ...
Deterritorializing Drawing - transformation/deformation
DEFF Research Database (Denmark)
Brabrand, Helle
2012-01-01
but also from within by sensations, body ‘images’ are different to all other images. Twisting these body images make a mode of operation of art. The paper will address the above issues discussing modes of operation and appearance of my actual project. Acting in the reality of drawing, the project confront...... the body, situated in real time and depth, with drawing transforming and deforming time and depth....
Solid state nuclear magnetic resonance studies of cross polarization from quadrupolar nuclei
Energy Technology Data Exchange (ETDEWEB)
De Paul, Susan M. [Univ. of California, Berkeley, CA (United States)
1997-08-01
The development of solid-state Nuclear Magnetic Resonance (NMR) has, to a large extent, focused on using spin-1/2 nuclei as probes to investigate molecular structure and dynamics. For such nuclei, the technique of cross polarization is well-established as a method for sensitivity enhancement. However, over two-thirds of the nuclei in the periodic table have a spin-quantum number greater than one-half and are known as quadrupolar nuclei. Such nuclei are fundamental constituents of many inorganic materials including minerals, zeolites, glasses, and gels. It is, therefore, of interest to explore the extent to which polarization can be transferred from quadrupolar nuclei. In this dissertation, solid-state NMR experiments involving cross polarization from quadrupolar nuclei to spin-1/2 nuclei under magic-angle spinning (MAS) conditions are investigated in detail.
Energy Technology Data Exchange (ETDEWEB)
Vargas, Carlos E.; Bagatella-Flores, Norma [Universidad Veracruzana, Facultad de Fisica, Veracruz (Mexico); Velazquez, Victor [Universidad Nacional Autonoma de Mexico, Facultad de Ciencias, Mexico D.F. (Mexico); Lerma-Hernandez, Sergio [Universidad Veracruzana, Facultad de Fisica, Veracruz (Mexico); Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico D.F. (Mexico)
2017-04-15
The large collectivity observed in the rare-earth region of the nuclear landscape is well known. The microscopic studies are difficult to perform in this region due to the enormous size of the valence spaces, a problem that can be avoided by means of the use of symmetry-based models. Here we present calculations for electromagnetic properties of {sup 160-170}Dy nuclei within the pseudo-SU(3) scheme. The model Hamiltonian includes the preserving symmetry Q.Q term and the symmetry-breaking Nilsson and pairing terms, systematically parametrized for all members of the chain. The model is used to calculate B(E2) and B(M1) inter-band transition strengths between the ground state, γ and β-bands. In addition, we present results for quadrupole moments and g factors in these rotational bands. The results show that the pseudo-SU(3) shell model is a powerful microscopic theory for a description of electromagnetic properties of states in the normal parity sector in heavy deformed nuclei. (orig.)
Grosse, E.; Junghans, A. R.; Wilson, J. N.
2017-11-01
The basic parameters for calculations of radiative neutron capture, photon strength functions and nuclear level densities near the neutron separation energy are determined based on experimental data without an ad hoc assumption about axial symmetry—at variance to previous analysis. Surprisingly few global fit parameters are needed in addition to information on nuclear deformation, taken from Hartree Fock Bogolyubov calculations with the Gogny force, and the generator coordinator method assures properly defined angular momentum. For a large number of nuclei the GDR shapes and the photon strength are described by the sum of three Lorentzians, extrapolated to low energies and normalised in accordance to the dipole sum rule. Level densities are influenced strongly by the significant collective enhancement based on the breaking of shape symmetry. The replacement of axial symmetry by the less stringent requirement of invariance against rotation by 180° leads to a novel prediction for radiative neutron capture. It compares well to recent compilations of average radiative widths and Maxwellian average cross sections for neutron capture by even target nuclei. An extension to higher spin promises a reliable prediction for various compound nuclear reactions also outside the valley of stability. Such predictions are of high importance for future nuclear energy systems and waste transmutation as well as for the understanding of the cosmic synthesis of heavy elements.
Adult Spinal Deformity: Sagittal Imbalance
Directory of Open Access Journals (Sweden)
Cavanilles-Walker JM
2014-10-01
Full Text Available Spinal sagittal imbalance, deformity of the spine in the sagittal plane, is nowadays a major cause of pain and disability among patients presenting to the spine clinic in daily practice. Normal sagittal spinal balance is a result of mutual articulation of the pelvis and the spine in the sagittal plane. Sagittal imbalance of the spine could be related to many spinal pathologies interesting primarily the spine or could appear after an instrumentation spinal surgery. Variations in the spine sagittal alignment can be compensated by compensatory mechanisms occurring in the spine, pelvis and lower limb areas. The main objective of these mechanisms is to allow the patient to keep an erect position within the cone of economy in an energy-efficient way. Once a spinal deformity surpasses these compensatory mechanisms surgical intervention is often requested. In this paper the Authors performed comprehensive a critical analysis of the rigidity of the deformity, including the spinal and pelvic parameters. The compensatory mechanisms are paramount in order to be able to offer a tailored solution to these patients. Since conservative measures fail in most patients, successful management of these patients requires achieving fusion of a balanced spine. Appropriate preoperative optimization as well as appropriate surgical preoperative planning are critical in order to avoid potential complications. Selecting the appropriate surgical technique to achieve spinal balance is crucial to success.
$\\beta$-delayed neutrons from oriented $^{137,139}$I and $^{87,89}$Br nuclei
We propose a world-first measurement of the angular distribution of $\\beta$‐delayed n and $\\gamma$-radiation from oriented $^{137, 139}$I and $^{87,89}$Br nuclei, polarised at low temperature at the NICOLE facility. $\\beta$-delayed neutron emission is an increasingly important decay mechanism as the drip line is approached and its detailed understanding is essential to phenomena as fundamental as the r‐process and practical as the safe operation of nuclear power reactors. The experiments offer sensitive tests of theoretical input concerning the allowed and first‐forbidden $\\beta$‐decay strength, the spin-density of neutron emitting states and the partial wave barrier penetration as a function of nuclear deformation. In $^{137}$I and $^{87}$Br the decay feeds predominantly the ground state of the daughters $^{136}$Xe and $^{86}$Kr whereas in $^{139}$I and $^{89}$Br we will explore the use of n-$\\gamma$- coincidence to study neutron transitions to the first and second excited states in the daughters...
$\\beta$-delayed neutrons from oriented $^{137,139}$I and $^{87,89}$Br nuclei
Grzywacz, Robert; Stone, Nicholas; Köster, Ulli; Singh, Barlaj; Bingham, Carrol; Gaulard, S; Kolos, Karolina; Madurga, Miguel; Nikolov, J; Otsubo, T; Roccia, S; Veskovic, Miroslav; Walker, Phil; Walters, William
2013-01-01
We propose a world-‐first measurement of the angular distribution of $\\beta$-‐delayed n and $\\gamma$- radiation from oriented $^{137, 139}$I and $^{87,89}$Br nuclei, polarised at low temperature at the NICOLE facility. $\\beta$-‐delayed neutron emission is an increasingly important decay mechanism as the drip line is approached and its detailed understanding is essential to phenomena as fundamental as the r‐process and practical as the safe operation of nuclear power reactors. The experiments offer sensitive tests of theoretical input concerning the allowed and first-‐forbidden $\\beta$‐decay strength, the spin-‐density of neutron emitting states and the partial wave barrier penetration as a function of nuclear deformation. In $^{137}$I and $^{87}$Br the decay feeds predominantly the ground state of the daughters $^{136}$Xe and $^{86}$Kr whereas in $^{139}$I and $^{89}$Br we will explore the use of n-$\\gamma$- coincidence to study neutron transitions to the first and second excited state...
Instrumentation and fusion for congenital spine deformities.
Hedequist, Daniel J
2009-08-01
A retrospective clinical review. To review the use of modern instrumentation of the spine for congenital spinal deformities. Spinal instrumentation has evolved since the advent of the Harrington rod. There is a paucity of literature, which discusses the use of modern spinal instrumentation in congenital spine deformity cases. This review focuses on modern instrumentation techniques for congenital scoliosis and kyphosis. A systematic review was performed of the literature to discuss spinal implant use for congenital deformities. Spinal instrumentation may be safely and effectively used in cases of congenital spinal deformity. Spinal surgeons taking care of children with congenital spine deformities need to be trained in all aspects of modern spinal instrumentation.
Quantification and validation of soft tissue deformation
DEFF Research Database (Denmark)
Mosbech, Thomas Hammershaimb; Ersbøll, Bjarne Kjær; Christensen, Lars Bager
2009-01-01
We present a model for soft tissue deformation derived empirically from 10 pig carcases. The carcasses are subjected to deformation from a known single source of pressure located at the skin surface, and the deformation is quantified by means of steel markers injected into the tissue. The steel...... markers are easy to distinguish from the surrounding soft tissue in 3D computed tomography images. By tracking corresponding markers using methods from point-based registration, we are able to accurately quantify the magnitude and propagation of the induced deformation. The deformation is parameterised...
Eliminating deformations in fluorescence emission difference microscopy.
You, Shangting; Kuang, Cuifang; Rong, Zihao; Liu, Xu
2014-10-20
We propose a method for eliminating the deformations in fluorescence emission difference microscopy (FED). Due to excessive subtraction, negative values are inevitable in the original FED method, giving rise to deformations. We propose modulating the beam to generate an extended solid focal spot and a hollow focal spot. Negative image values can be avoided by using these two types of excitation spots in FED imaging. Hence, deformations are eliminated, and the signal-to-noise ratio is improved. In deformation-free imaging, the resolution is higher than that of confocal imaging by 32%. Compared to standard FED imaging with the same level of deformations, our method provides superior resolution.
Deformed potential energy of $^{263}Db$ in a generalized liquid drop model
Chen Bao Qiu; Zhao Yao Lin; 10.1088/0256-307X/20/11/009
2003-01-01
The macroscopic deformed potential energy for super-heavy nuclei /sup 263/Db, which governs the entrance and alpha decay channels, is determined within a generalized liquid drop model (GLDM). A quasi- molecular shape is assumed in the GLDM, which includes volume-, surface-, and Coulomb-energies, proximity effects, mass asymmetry, and an accurate nuclear radius. The microscopic single particle energies derived from a shell model in an axially deformed Woods- Saxon potential with a quasi-molecular shape. The shell correction is calculated by the Strutinsky method. The total deformed potential energy of a nucleus can be calculated by the macro-microscopic method as the summation of the liquid-drop energy and the Strutinsky shell correction. The theory is applied to predict the deformed potential energy of the experiment /sup 22/Ne+/sup 241/Am to /sup 263/Db* to /sup 259/Db+4 n, which was performed on the Heavy Ion Accelerator in Lanzhou. It is found that the neck in the quasi-molecular shape is responsible for t...
Effect of deformation and orientation on spin orbit density dependent nuclear potential
Mittal, Rajni; Kumar, Raj; Sharma, Manoj K.
2017-11-01
Role of deformation and orientation is investigated on spin-orbit density dependent part VJ of nuclear potential (VN=VP+VJ) obtained within semi-classical Thomas Fermi approach of Skyrme energy density formalism. Calculations are performed for 24-54Si+30Si reactions, with spherical target 30Si and projectiles 24-54Si having prolate and oblate shapes. The quadrupole deformation β2 is varying within range of 0.023 ≤ β2 ≤0.531 for prolate and -0.242 ≤ β2 ≤ -0.592 for oblate projectiles. The spin-orbit dependent potential gets influenced significantly with inclusion of deformation and orientation effect. The spin-orbit barrier and position gets significantly influenced by both the sign and magnitude of β2-deformation. Si-nuclei with β220. The possible role of spin-orbit potential on barrier characteristics such as barrier height, barrier curvature and on the fusion pocket is also probed. In reference to prolate and oblate systems, the angular dependence of spin-orbit potential is further studied on fusion cross-sections.
Nuclear deformability and telomere dynamics are regulated by cell geometric constraints.
Makhija, Ekta; Jokhun, D S; Shivashankar, G V
2016-01-05
Forces generated by the cytoskeleton can be transmitted to the nucleus and chromatin via physical links on the nuclear envelope and the lamin meshwork. Although the role of these active forces in modulating prestressed nuclear morphology has been well studied, the effect on nuclear and chromatin dynamics remains to be explored. To understand the regulation of nuclear deformability by these active forces, we created different cytoskeletal states in mouse fibroblasts using micropatterned substrates. We observed that constrained and isotropic cells, which lack long actin stress fibers, have more deformable nuclei than elongated and polarized cells. This nuclear deformability altered in response to actin, myosin, formin perturbations, or a transcriptional down-regulation of lamin A/C levels in the constrained and isotropic geometry. Furthermore, to probe the effect of active cytoskeletal forces on chromatin dynamics, we tracked the spatiotemporal dynamics of heterochromatin foci and telomeres. We observed increased dynamics and decreased correlation of the heterochromatin foci and telomere trajectories in constrained and isotropic cell geometry. The observed enhanced dynamics upon treatment with actin depolymerizing reagents in elongated and polarized geometry were regained once the reagent was washed off, suggesting an inherent structural memory in chromatin organization. We conclude that active forces from the cytoskeleton and rigidity from lamin A/C nucleoskeleton can together regulate nuclear and chromatin dynamics. Because chromatin remodeling is a necessary step in transcription control and its memory, genome integrity, and cellular deformability during migration, our results highlight the importance of cell geometric constraints as critical regulators in cell behavior.
Blood vessels and desmin control the positioning of nuclei in skeletal muscle fibers
DEFF Research Database (Denmark)
Ralston, E; Lu, Z; Biscocho, N
2006-01-01
Skeletal muscle fibers contain hundreds to thousands of nuclei which lie immediately under the plasmalemma and are spaced out along the fiber, except for a small cluster of specialized nuclei at the neuromuscular junction. How the nuclei attain their positions along the fiber is not understood...
Thermoelastic Seasonal Deformation in Chinese Mainland
Directory of Open Access Journals (Sweden)
TAN Weijie
2017-09-01
Full Text Available In this paper, we explore the thermoelastic seasonal deformation in Chinese mainland based on the 260 GPS sites of crustal movement observation network of China (CMONOC. The results show that the change of land surface temperature can induce remarkable surface deformation in China. The most affected site is HLAR in Inner Mongolia, China. Its seasonal amplitude of surface deformation is about~2.293mm. and the site HIYS in Hainan is the least affected. The seasonal amplitude of surface deformation is about~0.177mm. Applying the thermoelastic seasonal deformation information in GRACE data analysis and the Mass loading models (MODEL, refined three-dimensional seasonal deformation map are derived. Taking GPS measurements as references, refined results show that the annual deformation derived from the MODEL and the GRACE data have been improved by about 6%,6%,2%;16%,5%,15% in the east, north and height components respectively.
Increased ionization supports growth of aerosols into cloud condensation nuclei
DEFF Research Database (Denmark)
Svensmark, H.; Enghoff, M. B.; Shaviv, N. J.
2017-01-01
Ions produced by cosmic rays have been thought to influence aerosols and clouds. In this study, the effect of ionization on the growth of aerosols into cloud condensation nuclei is investigated theoretically and experimentally. We show that the mass-flux of small ions can constitute an important...... addition to the growth caused by condensation of neutral molecules. Under atmospheric conditions the growth from ions can constitute several percent of the neutral growth. We performed experimental studies which quantify the effect of ions on the growth of aerosols between nucleation and sizes >20 nm...... and find good agreement with theory. Ion-induced condensation should be of importance not just in Earth’s present day atmosphere for the growth of aerosols into cloud condensation nuclei under pristine marine conditions, but also under elevated atmospheric ionization caused by increased supernova activity....
Increased ionization supports growth of aerosols into cloud condensation nuclei.
Svensmark, H; Enghoff, M B; Shaviv, N J; Svensmark, J
2017-12-19
Ions produced by cosmic rays have been thought to influence aerosols and clouds. In this study, the effect of ionization on the growth of aerosols into cloud condensation nuclei is investigated theoretically and experimentally. We show that the mass-flux of small ions can constitute an important addition to the growth caused by condensation of neutral molecules. Under atmospheric conditions the growth from ions can constitute several percent of the neutral growth. We performed experimental studies which quantify the effect of ions on the growth of aerosols between nucleation and sizes >20 nm and find good agreement with theory. Ion-induced condensation should be of importance not just in Earth's present day atmosphere for the growth of aerosols into cloud condensation nuclei under pristine marine conditions, but also under elevated atmospheric ionization caused by increased supernova activity.
Vaporization of comet nuclei - Light curves and life times
Cowan, J. J.; Ahearn, M. F.
1979-01-01
The effects of vaporization from the nucleus of a comet are examined and it is shown that a latitude dependence of vaporization can explain the asymmetries in cometary light curves. An attempt is made to explain the observed variation in molecular production rates with heliocentric distance when employing CO2 and clathrate hydrate ice as cometary nuclei substances. The energy balance equation and the vapor pressure equations of water and CO2 are used in calculating the vaporization from a surface. Calculations were carried out from both dry-ice and water-ice nuclei, using a variety of different effective visual albedos, but primarily for a thermal infrared of 0 (emission). Attention is given to cometary lifetimes and light curves and it was determined that the asymmetry in light curves occurs (occasionally) as a 'seasonal' effect due to a variation in the angle between the comet's rotation axis and the sun-comet line.
Collective and single particle states in medium mass vibrational nuclei
Suliman, G
2001-01-01
The particle-core coupling model has been employed to describe the low lying nuclear excitations in the vibrational odd-A nuclei. In the frame of this model the following observables were calculated: excitation energies, spin and parity quantum numbers, electric quadrupole moments, magnetic dipole moments and reduced transition probabilities. Two computer codes were employed. The first one, PCOREC, diagonalized the Hamiltonian providing the eigenvectors and eigenvalues. The second one, PCORECTR, starts from the eigenvector computer by the first program and computes the observables which are compared we results of experiments. A good description of the experimental data has been obtained for the sup 1 sup 3 sup 3 Sb, sup 1 sup 2 sup 3 Sb and sup 1 sup 2 sup 5 Sb nuclei. (authors)
POLAREX. Study of polarized exotic nuclei at millikelvin temperatures
Energy Technology Data Exchange (ETDEWEB)
Risegari, L.; Astier, A.; Audi, G.; Cabaret, S.; Gaulard, C.; Georgiev, G. [CSNSM, Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Orsay (France); Stone, N.J. [University of Oxford, Department of Physics, Oxford (United Kingdom); University of Tennessee, Department of Physics and Astronomy, Knoxville, TN (United States); Stone, J.R. [University of Oxford, Department of Physics, Oxford (United Kingdom); University of Tennessee, Department of Physics and Astronomy, Knoxville, TN (United States); University of Maryland, Department of Chemistry and Biochemistry, College Park, MD (United States)
2009-12-15
POLAREX (POLARization of EXotic nuclei) is a new facility for the study of nuclear magnetic moments and decay modes of exotic nuclei using the established On-Line Nuclear Orientation (OLNO) method. A radioactive beam of interest is implanted into a ferromagnetic host foil held at a temperature of order 10mK in a {sup 3}He-{sup 4}He dilution refrigerator. The foil is magnetized by an applied magnetic field and the nuclear spins become polarized through the internal hyperfine field. The angular distribution of decay products from the polarized sample is measured. Accurate values of nuclear moment are obtained by NMR. The new facility will have access to neutron-rich nuclides produced at the ALTO facility (Linear Accelerator at Orsay Tandem) by fission induced by electrons from the linear electron accelerator. Basic concepts and initial tests are outlined. (orig.)
Communication: Thermodynamics of stacking disorder in ice nuclei
Quigley, D.
2014-09-01
A simple Ising-like model for the stacking thermodynamics of ice 1 is constructed for nuclei in supercooled water, and combined with classical nucleation theory. For relative stabilities of cubic and hexagonal ice I within the range of experimental estimates, this predicts critical nuclei are stacking disordered at strong sub-cooling, consistent with recent experiments. At higher temperatures nucleation of pure hexagonal ice is recovered. Lattice-switching Monte-Carlo is applied to accurately compute the relative stability of cubic and hexagonal ice for the popular mW model of water. Results demonstrate that this model fails to adequately capture the relative energetics of the two polytypes, leading to stacking disorder at all temperatures.
Lattice effective field theory for medium-mass nuclei
Energy Technology Data Exchange (ETDEWEB)
Lähde, Timo A., E-mail: t.laehde@fz-juelich.de [Institute for Advanced Simulation, Institut für Kernphysik, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Epelbaum, Evgeny; Krebs, Hermann [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44870 Bochum (Germany); Lee, Dean [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Meißner, Ulf-G. [Institute for Advanced Simulation, Institut für Kernphysik, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); JARA – High Performance Computing, Forschungszentrum Jülich, D-52425 Jülich (Germany); Rupak, Gautam [Department of Physics and Astronomy, Mississippi State University, Mississippi State, MS 39762 (United States)
2014-05-01
We extend Nuclear Lattice Effective Field Theory (NLEFT) to medium-mass nuclei, and present results for the ground states of alpha nuclei from {sup 4}He to {sup 28}Si, calculated up to next-to-next-to-leading order (NNLO) in the EFT expansion. This computational advance is made possible by extrapolations of lattice data using multiple initial and final states. For our soft two-nucleon interaction, we find that the overall contribution from multi-nucleon forces must change sign from attractive to repulsive with increasing nucleon number. This effect is not produced by three-nucleon forces at NNLO, but it can be approximated by an effective four-nucleon interaction. We discuss the convergence of the EFT expansion and the broad significance of our findings for future ab initio calculations.
Inclusive quasielastic scattering of polarized electrons from polarized nuclei
Energy Technology Data Exchange (ETDEWEB)
Amaro, J.E. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Center for Theoretical Physics]|[Universidad de Granada (Spain). Dept. de Fisica Moderna]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Lab. for Nuclear Science]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics; Caballero, J.A. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia]|[Sevilla Univ. (Spain). Dept. de Fisica Atomica, Molecular y Nuclear; Donnelly, T.W. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Center for Theoretical Physics]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Lab. for Nuclear Science]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics; Moya de Guerra, E. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia
1996-12-23
The inclusive quasielastic response functions that appear in the scattering of polarized electrons from polarized nuclei are computed and analyzed for several closed-shell-minus-one nuclei with special attention paid to {sup 39}K. Results are presented using two models for the ejected nucleon - when described by a distorted wave in the continuum shell model or by a plane wave in PWIA with on- and off-shell nucleons. Relativistic effects in kinematics and in the electromagnetic current have been incorporated throughout. Specifically, the recently obtained expansion of the electromagnetic current in powers only of the struck nucleon`s momentum is employed for the on-shell current and the effects of the first-order terms (spin-orbit and convection) are compared with the zeroth-order (charge and magnetization) contributions. The use of polarized inclusive quasielastic electron scattering as a tool for determining near-valence nucleon momentum distributions is discussed. (orig.).
Multiple parton scattering in nuclei: Parton energy loss
Energy Technology Data Exchange (ETDEWEB)
Wang, Xin-Nian; Guo, Xiao-feng
2001-02-17
Multiple parton scattering and induced parton energy loss are studied in deeply inelastic scattering (DIS) off nuclei. The effect of multiple scattering of a highly off-shell quark and the induced parton energy loss is expressed in terms of the modification to the quark fragmentation functions. The authors derive such modified quark fragmentation functions and their QCD evolution equations in DIS using the generalized factorization of higher twist parton distributions. They consider double-hard and hard-soft parton scattering as well as their interferences in the same framework. The final result, which depends on both the diagonal and off-diagonal twist-four parton distributions in nuclei, demonstrates clearly the Landau-Pomeranchuk-Migdal interference features and predicts a unique nuclear modification of the quark fragmentation functions.