2,820 research outputs found
Calculation of microscopic nuclear level densities based on covariant density functional theory
A microscopic method for calculating nuclear level density (NLD) based on the
covariant density functional theory (CDFT) is developed. The particle-hole
state density is calculated by combinatorial method using the single-particle
levels schemes obtained from the CDFT. Then the level densities are obtained by
taking into account collective effects such as vibration and rotation. Our
results are compared with those from other NLD models, including
phenomenological, microstatistical, and non-relativistic HFB combinatorial
models. The comparison suggests that the general trends among these models are
basically the same, except for some deviations from different NLD models. In
addition, the NLDs of the CDFT combinatorial method with normalization are
compared with experimental data, including the observed cumulative number of
levels at low excitation energy and the measured NLDs. Compared with the
existing experimental data, the CDFT combinatorial method can give reasonable
results.Comment: 9 pages, 8 figure
Bis(μ-4,4;6,6-bisÂ(biphenyl-2,2′-diyldiÂoxy)-2,2-bisÂ{2-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]phenÂoxy}cycloÂtriphosphazene)di-μ-chlorido-bisÂ[chloridoÂcopper(II)]
In the crystal of the title compound, [Cu2Cl4(C50H32N9O8P3)2], the binuclear molÂecule is located across an inversion center. Each Cu2+ cation is coordinated by two pyridine N atoms from symmetry-related 4,4;6,6-bisÂ(biphenyl-2,2′-diyldiÂoxy)-2,2-bisÂ{2-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]phenÂoxy}cycloÂtriphosphazene (L) ligands, a pair of bridging Cl− anions and a terminal Cl− anion, forming a distorted CuCl3N2 square-pyramidal geometry. Weak intraÂmolecular C—H⋯O and interÂmolecular C—H⋯N interÂactions occur in the crystal
Design and Mechanical Compatibility of Nylon Bionic Cancellous Bone Fabricated by Selective Laser Sintering
In order to avoid the stress shielding phenomenon in orthopedic bionic bone implantation, it is necessary to consider the design of mechanical compatible implants imitating the host bone. In this study, we developed a novel cancellous bone structure design method aimed at ensuring the mechanical compatibility between the bionic bone and human bone by means of computer-aided design (CAD) and finite element analysis technology (specifically, finite element modeling (FEM)). An orthogonal lattice model with volume porosity between 59% and 96% was developed by means of CAD. The effective equivalent elastic modulus of a honeycomb structure with square holes was studied by FEM simulation. With the purpose of verifying the validity of the cancellous bone structure design method, the honeycomb structure was fabricated by selective laser sintering (SLS) and the actual equivalent elastic modulus of the honeycomb structure was measured with a uniaxial compression test. The experimental results were compared with the FEM values and the predicted values. The results showed that the stiffness values of the designed structures were within the acceptable range of human cancellous bone of 50-500 MPa, which was similar to the stiffness values of human vertebrae L1 and L5. From the point of view of mechanical strength, the established cellular model can effectively match the elastic modulus of human vertebrae cancellous bone. The functional relationship between the volume porosity of the nylon square-pore honeycomb structure ranging from 59% to 96% and the effective elastic modulus was established. The effect of structural changes related to the manufacture of honeycomb structures on the equivalent elastic modulus of honeycomb structures was studied quantitatively by finite element modeling
Establishing the heavy quark spin and light flavor molecular multiplets of the , and
Recently, the LHCb Collaboration reported a near-threshold enhancement,
, in the invariant mass distribution. We show that the
data can be well described by either a bound or a virtual state below the
threshold. The mass given by the pole position is
MeV. Using this mass and the existing information on the and
resonances, a complete spectrum of the -wave hadronic molecules
formed by a pair of ground state charmed and anticharmed mesons is established.
Thus, pole positions of the partners of the , and the
newly observed state are predicted. Calculations have been carried
out at the leading order of nonrelativistic effective field theory and
considering both heavy quark spin and light flavor SU(3) symmetries, though
conservative errors from the breaking of these symmetries are provided.Comment: 19 pages, 4 figures and 5 tables. Version to appear in PR
Effect of rs1344706 in the ZNF804A gene on the brain network.
ZNF804A rs1344706 (A/C) was the first SNP that reached genome-wide significance for schizophrenia. Recent studies have linked rs1344706 to functional connectivity among specific brain regions. However, no study thus far has examined the role of this SNP in the entire functional connectome. In this study, we used degree centrality to test the role of rs1344706 in the whole-brain voxel-wise functional connectome during the resting state. 52 schizophrenia patients and 128 healthy controls were included in the final analysis. In our whole-brain analysis, we found a significant interaction effect of genotype × diagnosis at the precuneus (PCU) (cluster size = 52 voxels, peak voxel MNI coordinates: x = 9, y = - 69, z = 63, F = 32.57, FWE corrected P < 0.001). When we subdivided the degree centrality network according to anatomical distance, the whole-brain analysis also found a significant interaction effect of genotype × diagnosis at the PCU with the same peak in the short-range degree centrality network (cluster size = 72 voxels, F = 37.29, FWE corrected P < 0.001). No significant result was found in the long-range degree centrality network. Our results elucidated the contribution of rs1344706 to functional connectivity within the brain network, and may have important implications for our understanding of this risk gene's role in functional dysconnectivity in schizophrenia
Understanding the and charmonium(-like) states near 3.9 GeV
We propose that the observed in the channel is the
same state as the , and the , observed in the
channel, is an -wave hadronic molecule. In
addition, the {component in the } assigned to
the in the current {\it Review of Particle Physics} has the same
origin as the , which has a mass around 3.94~GeV. To check the
proposal, the available data in the and channels from
both decays and fusion reaction are analyzed considering
both the --- coupled
channels with and a state introduced additionally. It is
found that all the data in different processes can be simultaneously well
reproduced, and the coupled-channel dynamics produce four hidden-charm scalar
molecular states with masses around 3.73, 3.94, 3.99 and 4.23~GeV,
respectively. The results may deepen our understanding of the spectrum of
charmonia as well as of the interactions between charmed hadrons.Comment: 15 pages, 6 figures, 2 tables, to apear in Sci. Bul
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