19,219 research outputs found
Nuclear modification factor in intermediate-energy heavy-ion collisions
The transverse momentum dependent nuclear modification factors (NMF), namely
, is investigated for protons produced in Au + Au at 1 GeV within
the framework of the isospin-dependent quantum molecular dynamics (IQMD) model.
It is found that the radial collective motion during the expansion stage
affects the NMF at low transverse momentum a lot. By fitting the transverse
mass spectra of protons with the distribution function from the Blast-Wave
model, the magnitude of radial flow can be extracted. After removing the
contribution from radial flow, the can be regarded as a thermal one
and is found to keep unitary at transverse momentum lower than 0.6 GeV/c and
enhance at higher transverse momentum, which can be attributed to Cronin
effect.Comment: 8 pages, 5 figures; aceepted by Physics Letters
Excitation Energy as a Basic Variable to Control Nuclear Disassembly
Thermodynamical features of Xe system is investigated as functions of
temperature and freeze-out density in the frame of lattice gas model. The
calculation shows different temperature dependence of physical observables at
different freeze-out density. In this case, the critical temperature when the
phase transition takes place depends on the freeze-out density. However, a
unique critical excitation energy reveals regardless of freeze-out density when
the excitation energy is used as a variable insteading of temperature.
Moreover, the different behavior of other physical observables with temperature
due to different vanishes when excitation energy replaces temperature.
It indicates that the excitation energy can be seen as a more basic quantity to
control nuclear disassembly.Comment: 3 pages, 2 figures, Revte
Surface Damage of Tangshan Earthquake and Characteristics of Response Spectrum of Ground Movement
The intensive ground movement of seismic region was an essential factor in causing ground damages. Damages in historical events signified that the extent of destruction not only conformed to the epicentral distance but also related to geomorphology, soil type and ground structure. Different combination of ground lithology may reflected directly the enhancement and attenuation of seismic wave during its propagation and it had also dominating influence on ground movement, different damages and seismic excitation of the same ground. Hence the amplitude and type of seismic response spectra were determined. In this paper, ground movement and damage feature on geomorphology units of various ground as well as the influence of seismic wave field on earthquake damages were analyzed by seismic ground response. Site zoning was carried out based on the types of response spectra
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