Publisher's Note: Nucleation and cluster formation in low-density nucleonic matter: A mechanism for ternary fission [Phys. Rev. C 90, 011601(R) (2014)]

2014 ◽  
Vol 90 (1) ◽  
Author(s):  
S. Wuenschel ◽  
H. Zheng ◽  
K. Hagel ◽  
B. Meyer ◽  
M. Barbui ◽  
...  
Keyword(s):  
Cluster Formation ◽  
Ternary Fission ◽  
Low Density

scholarly journals Nucleation and cluster formation in low-density nucleonic matter: A mechanism for ternary fission

2014 ◽  
Vol 90 (1) ◽  
Author(s):  
S. Wuenschel ◽  
H. Zheng ◽  
K. Hagel ◽  
B. Meyer ◽  
M. Barbui ◽  
...  
Keyword(s):  
Cluster Formation ◽  
Ternary Fission ◽  
Low Density

scholarly journals The significance of biomass allocation to population growth of the invasive species Ambrosia artemisiifolia and Ambrosia trifida with different densities

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wenxuan Zhao ◽  
Tong Liu ◽  
Yan Liu ◽  
Hanyue Wang ◽  
Ruili Wang ◽  
...  
Keyword(s):  
Cluster Formation ◽  
Ambrosia Artemisiifolia ◽  
High Density ◽  
High Population ◽  
Leaf Biomass ◽  
Total Biomass ◽  
Low Density ◽  
Population Densities ◽  
Ambrosia Trifida ◽  
Short Period

Abstract Background Ambrosia artemisiifolia and Ambrosia trifida are globally distributed harmful and invasive weeds. High density clusters play an important role in their invasion. For these two species, the early settled populations are distributed at low densities, but they can rapidly achieve high population densities in a short period of time. However, their response to intraspecific competition to improve the fitness for rapid growth and maintenance of high population densities remains unclear. Therefore, to determine how these species form and maintain high population densities, individual biomass allocations patterns between different population densities (low and high), and plasticity during seedling, vegetative, breeding and mature stages were compared. In 2019, we harvested seeds at different population densities and compared them, and in 2020, we compared the number of regenerated plants across the two population densities. Results Most biomass was invested in the stems of both species. Ambrosia trifida had the highest stem biomass distribution, of up to 78%, and the phenotypic plasticity of the stem was the highest. Path analysis demonstrated that at low-density, total biomass was the biggest contributor to seed production, but stem and leaf biomass was the biggest contributors to high-density populations. The number of seeds produced per plant was high in low-density populations, while the seed number per unit area was huge in high-density populations. In the second year, the number of low-density populations increased significantly. A. artemisiifolia and A. trifida accounted for 75.6% and 68.4% of the mature populations, respectively. Conclusions High input to the stem is an important means to regulate the growth of the two species to cope with different densities. These two species can ensure reproductive success and produce appropriate seed numbers. Therefore, they can maintain a stable population over time and quickly form cluster advantages. In the management, early detection of both species and prevention of successful reproduction by chemical and mechanical means are necessary to stop cluster formation and spread.

LOW DENSITY NUCLEAR MATTER IN FERMI ENERGY COLLISIONS

2010 ◽  
Vol 19 (08n09) ◽  
pp. 1513-1522
Author(s):  
L. QIN ◽  
K. HAGEL ◽  
R. WADA ◽  
Z. CHEN ◽  
M. HUANG ◽  
...  
Keyword(s):  
Effective Interaction ◽  
Cluster Formation ◽  
Heavy Ion ◽  
Alpha Particles ◽  
Low Density ◽  
Free Energies ◽  
Mass Fractions ◽  
Cluster Properties ◽  
Medium Modifications ◽  
Density Matter

Recent heavy ion reaction studies aimed at elucidating the properties of low density matter produced in near Fermi-energies are discussed. At the lowest densities and temperatures large alpha mass fractions are observed. The symmetry free energies derived from isoscaling analyses are far above those obtained in common effective interaction calculations, reflecting cluster formation, primarily of alpha particles, not included in such calculations. Theoretical modeling of these results requires the consideration of cluster formation and medium modifications of cluster properties.

scholarly journals Peculiarities of cluster formation in true ternary fission of 252Cf and 236U*

2014 ◽  
Vol 89 (5) ◽  
pp. 054022 ◽  
Author(s):  
A K Nasirov ◽  
W von Oertzen ◽  
A I Muminov ◽  
R B Tashkhodjaev
Keyword(s):  
Cluster Formation ◽  
Ternary Fission

CLUSTERED LOW DENSITY NUCLEAR MATTER IN NEAR FERMI ENERGY COLLISIONS

2011 ◽  
Vol 20 (04) ◽  
pp. 987-992
Author(s):  
J. B. NATOWITZ ◽  
K. HAGEL ◽  
R. WADA ◽  
L. QIN ◽  
Z. CHEN ◽  
...  
Keyword(s):  
Nuclear Matter ◽  
Fermi Energy ◽  
Effective Interaction ◽  
Cluster Formation ◽  
Heavy Ion ◽  
Alpha Particles ◽  
Low Density ◽  
Free Energies ◽  
Ion Collisions ◽  
Density Matter

Current research on clustering in low density matter formed in near Fermi energy heavy ion collisions is discussed Temperature and density dependent symmetry free energies derived from isoscaling analyses of the yields of nuclei with A ≤ 4 are far above those obtained in common effective interaction calculations, reflecting cluster formation, primarily of alpha particles, not included in such calculations.

Density effects on ion mobilities in electron attaching fluids: CS2, SF6, and C6F6

1990 ◽  
Vol 68 (9) ◽  
pp. 1527-1531 ◽  
Author(s):  
Norman Gee ◽  
G. Ramanan ◽  
Gordon R. Freeman
Keyword(s):  
Ion Mobility ◽  
Cluster Formation ◽  
Local Environment ◽  
Phase Changes ◽  
Molecular Cluster ◽  
Low Density ◽  
Fluid Density ◽  
Arrhenius Model ◽  
Liquid Transition ◽  
Molecule Transport

Ion mobilities μ were measured at densities n ranging from those of the low density gas (n < 0.01 nc, where nc = critical fluid density) through the dense gas and low-density liquid transition region (~0.5nc to 2nc) to the normal liquid (~3nc). The mobility at a given density was constant over a 10-fold variation of electric field strength, typically in the range 0.1 < E(MV/m) < 5. In the gas phase changes in mobility were dominated by changes in gas density. Comparison with neutral molecule transport in SF6 was used to illustrate the change in the effect of the ion on its local environment from that of molecular cluster formation to that of liquid electrostriction as density was increased. In the liquid, changes in ion mobility are dominated by changes in free volume. Mobilities in the present liquids could be described without reference to the activation energies suggested by the Arrhenius model. Keywords: ion, mobility, fluid, density, electron attaching.

scholarly journals Light element ($$Z=1,2$$) production from spontaneous ternary fission of $$^{252}$$Cf

2020 ◽  
Vol 56 (9) ◽  
Author(s):  
G. Röpke ◽  
J. B. Natowitz ◽  
H. Pais
Keyword(s):  
Bound States ◽  
Cluster Formation ◽  
Light Element ◽  
Dense Matter ◽  
Ternary Fission ◽  
Nucleon Density ◽  
Unstable Nuclei ◽  
Chemical Potentials ◽  
He Isotopes ◽  
Scattering Phase

Abstract The yields of light elements ($$Z=1,2$$ Z = 1 , 2 ) obtained from spontaneous ternary fission of $$^{252}$$ 252 Cf are treated within a nonequilibrium approach, and the contribution of unstable nuclei and excited bound states is taken into account. These light cluster yields may be used to probe dense matter, and to infer in-medium corrections such as Pauli blocking which is determined by the nucleon density. Continuum correlations are calculated from scattering phase shifts using the Beth-Uhlenbeck formula, and the effect of medium modification is estimated. The relevant distribution is reconstructed from the measured yields of isotopes. This describes the state of the nucleon system at scission and cluster formation, using only three Lagrange parameters which are the nonequilibrium counterparts of the temperature and chemical potentials, as defined in thermodynamic equilibrium. We concluded that a simple nuclear statistical equilibrium model neglecting continuum correlations and medium effects is not able to describe the measured distribution of H and He isotopes. Moreover, the freeze-out concept may serve as an important ingredient to the nonequilibrium approach using the relevant statistical operator concept.

Application of Improved Voltage Compensation in the SEM to Imaging of Organic Materials

1973 ◽  
Vol 31 ◽  
pp. 444-445
Author(s):  
P.J. Killingworth ◽  
M. Warren
Keyword(s):  
Electron Beam ◽  
Organic Materials ◽  
Operating Parameters ◽  
Low Density ◽  
Beam Diameter ◽  
Incident Electron Beam ◽  
Specimen Material ◽  
Voltage Compensation ◽  
Selection Of ◽  
Scanning Electron

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.

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