32,329 research outputs found
Nuclear isotope thermometry
We discuss different aspects which could influence temperatures deduced from
experimental isotopic yields in the multifragmentation process. It is shown
that fluctuations due to the finite size of the system and distortions due to
the decay of hot primary fragments conspire to blur the temperature
determination in multifragmentation reactions. These facts suggest that caloric
curves obtained through isotope thermometers, which were taken as evidence for
a first-order phase transition in nuclear matter, should be investigated very
carefully.Comment: 9 pages, 7 figure
A Chemical Survey of the Batang Belungkung River and the Gombak River
A chemical survey of water quality in the Batang Belungkung River and the Gombak River was conducted
to assess the degree of pollution due to the continuing discharge of rubber and domestic wastes.
Levels of dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD),
nutrients (phosphorus and nitrogen), solid and trace elements (sodium, potassium, calcium and magnesium)
were monitored sequentially downriver. The Batang Belungkung River was found to be severely polluted
with anaerobic conditions existing downriver. The upper region of the Gombak River was relatively unpolluted
while the lower region of the Gombak River was found to be severely polluted. An increase of
approximately fourteen-fold was found in the oxygen demand in the lower region of the Gombak River
over the ten year period from 1968/69 to 1978/79
Non-thermalization in trapped atomic ion spin chains
Linear arrays of trapped and laser cooled atomic ions are a versatile
platform for studying emergent phenomena in strongly-interacting many-body
systems. Effective spins are encoded in long-lived electronic levels of each
ion and made to interact through laser mediated optical dipole forces. The
advantages of experiments with cold trapped ions, including high spatiotemporal
resolution, decoupling from the external environment, and control over the
system Hamiltonian, are used to measure quantum effects not always accessible
in natural condensed matter samples. In this review we highlight recent work
using trapped ions to explore a variety of non-ergodic phenomena in long-range
interacting spin-models which are heralded by memory of out-of-equilibrium
initial conditions. We observe long-lived memory in static magnetizations for
quenched many-body localization and prethermalization, while memory is
preserved in the periodic oscillations of a driven discrete time crystal state.Comment: 14 pages, 5 figures, submitted for edition of Phil. Trans. R. Soc. A
on "Breakdown of ergodicity in quantum systems
Probing nuclear symmetry energy with the sub-threshold pion production
Within the framework of semiclassical Boltzmann-Uehling-Uhlenbeck (BUU)
transport model, we investigated the effects of symmetry energy on the
sub-threshold pion using the isospin MDI interaction with the stiff and soft
symmetry energies in the central collision of Ca + Ca at the
incident beam energies of 100, 150, 200, 250 and 300 MeV/nucleon, respectively.
We find that the ratio of of sub-threshold charged pion
production is greatly sensitive to the symmetry energy, particularly around 100
MeV/nucleon energies. Large sensitivity of sub-threshold charged pion
production to nuclear symmetry energy may reduce uncertainties of probing
nuclear symmetry energy via heavy-ion collision.Comment: 5 pages, 5 figures, typo corrections, submitted to Chinese Physics
Letter
Effect of solid-to-solvent ratio on phenolic content and antioxidant capacities of “ Dukung Anak” (Phyllanthus niruri)
The objective of this study was to evaluate the effects of solid-to-solvent ratio (1:5. 1:10, 1:15
and 1:20) on the extraction of phenolic compounds (TPC and TFC) and antioxidant capacity
(ABTS and DPPH radical scavenging capacity) of
P. niruri
. Solid-to-solvent ratio showed
a significant effect for both phenolic compounds (TPC and TFC) and antioxidant capacity
(ABTS and DPPH radical scavenging capacity) with 1:20 was the condition for extracting the
highest of phenolic compounds (TPC and TFC) with a value of 5788.7 mg GAE/100 g DW and
1906.5 mg CE/100 g DW, respectively and exhibited high antioxidant capacities (ABTS and
DPPH radical scavenging capacities) with a value of 0.820 mM and 1.598 mM, respectively
among the four levels studied. TPC was positively and significantly correlated with ABTS and
DPPH (r=0.999 and r=0.999) under the effects of solid-to-solvent ratio as compared to TFC,
positively and strongly correlated (r=0.865 and r=0.868) with ABTS and DPPH
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