22,220 research outputs found
Possible dibaryons in the quark cluster model
In the framework of RGM, the binding energy of one channel
() and are studied in the
chiral SU(3) quark cluster model. It is shown that the binding energies of the
systems are a few tens of MeV. The behavior of the chiral field is also
investigated by comparing the results with those in the SU(2) and the extended
SU(2) chiral quark models. It is found that the symmetry property of the
system makes the contribution of the relative kinetic energy
operator between two clusters attractive. This is very beneficial for forming
the bound dibaryon. Meanwhile the chiral-quark field coupling also plays a very
important role on binding. The S-wave phase shifts and the corresponding
scattering lengths of the systems are also given.Comment: LeTex with 2 ps figure
Anti-shielding Effect and Negative Temperature in Instantaneously Reversed Electric Fields and Left-Handed Media
The connections between the anti-shielding effect, negative absolute
temperature and superluminal light propagation in both the instantaneously
reversed electric field and the left-handed media are considered in the present
paper. The instantaneous inversion of the exterior electric field may cause the
electric dipoles into the state of negative absolute temperature and therefore
give rise to a negative effective mass term of electromagnetic field (i. e.,
the electromagnetic field propagating inside the negative-temperature medium
will acquire an imaginary rest mass), which is said to result in the potential
superluminality effect of light propagation in this anti-shielding dielectric.
In left-handed media, such phenomena may also arise.Comment: 9 pages, Late
Difficulties in probing density dependent symmetry potential with the HBT interferometry
Based on the updated UrQMD transport model, the effect of the symmetry
potential energy on the two-nucleon HBT correlation is investigated with the
help of the coalescence program for constructing clusters, and the CRAB
analyzing program of the two-particle HBT correlation. An obvious non-linear
dependence of the neutron-proton (or neutron-neutron) HBT correlation function
() at small relative momenta on the stiffness factor of the
symmetry potential energy is found: when , the
increases rapidly with increasing , while it starts to saturate if
. It is also found that both the symmetry potential energy
at low densities and the conditions of constructing clusters at the late stage
of the whole process influence the two-nucleon HBT correlation with the same
power.Comment: 11 pages, 4 figure
Advantage of low quality in short life cycle products
This study explores the factors influencing customers’ purchase intention for low quality products. The traditional thinking is that products with high quality and low price will win more customers. However, we can notice that high quality products usually have high cost. Therefore, it is necessary to do more research on how customers can accept low quality products, in order to and help companies to win more customers and market share. We take fast fashion products and smart phones as empirical studies, collecting data from customer’s online survey. Based on the methodology of fuzzy-set qualitative comparative analysis (fsQCA), we analyses the relationship between the factors of short lifecycle, low quality, design and price and influence customer purchase intention. It shows that the product price and design are major driving factors for customers to accept low quality products. The result has implications for other industries that sell products with low cost
Self-induced charge currents in electromagnetic materials, photon effective rest mass and some related topics
The contribution of self-induced charge currents of metamaterial media to
photon effective rest mass is discussed in detail in the present paper. We
concern ourselves with two kinds of photon effective rest mass, i.e., the
frequency-dependent and frequency-independent effective rest mass. Based on
these two definitions, we calculate the photon effective rest mass in the
left-handed medium and the 2TDLM media, the latter of which is described by the
so-called two time derivative Lorentz material (2TDLM) model. Additionally, we
concentrate primarily on the torque, which is caused by the interaction between
self-induced charge currents in dilute plasma (e.g., the secondary cosmic rays)
and interstellar magnetic fields (ambient cosmic magnetic vector potentials),
acting on the torsion balance of the rotating torsion balance experiment.Comment: 11 pages, Late
An Expanding and Shift Scheme for Constructing Fourth-Order Difference Co-Arrays
An expanding and shift (EAS) scheme for efficient fourth-order difference co-array construction is proposed. It consists of two sparse sub-arrays, where one of them is modified and shifted according to the analysis provided. The number of consecutive lags of the proposed structure at the fourth order is consistently larger than two previously proposed methods. Two effective construction examples are provided with the second sparse sub-array chosen to be a two-level nested array, as such a choice can increase the number of consecutive lags further. Simulations are performed to show the improved performance by the proposed method in comparison with existing structures
Ferromagnetism in 2p Light Element-Doped II-oxide and III-nitride Semiconductors
II-oxide and III-nitride semiconductors doped by nonmagnetic 2p light
elements are investigated as potential dilute magnetic semiconductors (DMS).
Based on our first-principle calculations, nitrogen doped ZnO, carbon doped
ZnO, and carbon doped AlN are predicted to be ferromagnetic. The ferromagnetism
of such DMS materials can be attributed to a p-d exchange-like p-p coupling
interaction which is derived from the similar symmetry and wave function
between the impurity (p-like t_2) and valence (p) states. We also propose a
co-doping mechanism, using beryllium and nitrogen as dopants in ZnO, to enhance
the ferromagnetic coupling and to increase the solubility and activity
- …