147 research outputs found
Functionally Graded Concrete Structure
By inverse analysis, the concept, functionally gradient, is introduced into thick-walled lining to improve the supporting performance. Theoretical results show that for two linings with the same sizes, an ideal functionally graded lining (IFGL) has higher elastic ultimate bearing capacity than a traditional single-layered lining (TSL). But the IFGL model requires that the Young’s modulus should be a continuously monotonically increasing function in the radial direction, which, obviously, cannot be achieved currently for the concrete materials. In order to apply this idea to real lining, we use a simplest multilayered lining, a double-layered functionally graded lining (DFGL), as an approximate simulation of the IFGL. Then, we carried out elastoplastic analysis on IDFL and DFGL and model test on DFGL to assess the support performance. Results of elastoplastic analysis show that the elastic ultimate bearing capacities of both the IDFL and DFGL are higher than the traditional single-layered lining. Model tests also verify the conclusion
Exploring multi-band excitations of interacting Bose gases in a 1D optical lattice by coherent scattering
We use a coherent Bragg diffraction method to impart an external momentum to
ultracold bosonic atoms trapped in a one-dimensional optical lattice. This
method is based on the application of a single light pulse, with conditions
where scattering of photons can be resonantly amplified by the atomic density
grating. An oscillatory behavior of the momentum distribution resulting from
the time evolution in the lattice potential is then observed. By measuring the
oscillating frequencies, we extract multi-band energy structures of
single-particle excitations with zero pseudo-momentum transfer for a wide range
of lattice depths. The excitation energy structures reveal the interaction
effect through the whole range of lattice depth.Comment: 6 pages, 5 figure
On semi-classical limit of spatially homogeneous quantum Boltzmann equation: asymptotic expansion
We continue our previous work [Ling-Bing He, Xuguang Lu and Mario Pulvirenti,
Comm. Math. Phys., 386(2021), no. 1, 143223.] on the limit of the spatially
homogeneous quantum Boltzmann equation as the Planck constant tends
to zero, also known as the semi-classical limit. For general interaction
potential, we prove the following: (i). The spatially homogeneous quantum
Boltzmann equations are locally well-posed in some weighted Sobolev spaces with
quantitative estimates uniformly in . (ii). The semi-classical limit
can be further described by the following asymptotic expansion formula: This holds locally in time
in Sobolev spaces. Here and are solutions to the quantum
Boltzmann equation and the Fokker-Planck-Landau equation with the same initial
data.The convergent rate depends on the integrability of
the Fourier transform of the particle interaction potential. Our new
ingredients lie in a detailed analysis of the Uehling-Uhlenbeck operator from
both angular cutoff and non-cutoff perspectives.Comment: 32 pages
Kinetic theory and thermalization of weakly interacting fermions
Weakly interacting quantum fluids allow for a natural kinetic theory
description which takes into account the fermionic or bosonic nature of the
interacting particles. In the simplest cases, one arrives at the
Boltzmann-Nordheim equations for the reduced density matrix of the fluid. We
discuss here two related topics: the kinetic theory of the fermionic Hubbard
model, in which conservation of total spin results in an additional Vlasov type
term in the Boltzmann equation, and the relation between kinetic theory and
thermalization.Comment: 19 pages, submitted to proceedings of the conference "Macroscopic
Limits of Quantum Systems", Munich, Germany, March 20-April 1, 2017 (eds. D.
Cadamuro, M. Duell, W. Dybalski, S. Simonella
Overexpression of miR‑145 in U87 cells reduces glioma cell malignant phenotype and promotes survival after in vivo implantation
In the present study, we sought to elucidate the effect of miR‑145 on glioma cell progression and its mechanisms of action. We examined the effects of miR‑145 on proliferation and invasion of U87 glioma cells and on capillary tube formation. Our data show that restoration of miR‑145 in U87 glioma cells significantly reduced their in vitro proliferation, invasion and angiogenesis. However, decreased miR‑145 expression promoted U87 glioma cell proliferation, invasion and angiogenesis, and reduced-expression of miR‑145 increased ADAM17 and EGFR expression in U87 cells. Overexpression of miR‑145 reduced ADAM17 and EGFR expression. VEGF secretion and VEGF expression were decreased by increased miR‑145 expression in U87 cells and were reversed by miR‑145 downregulation in vitro. Nude mice with intracerebral implantation of U87 overexpressing miR‑145 cells exhibited significantly reduced tumor growth and promoted survival compared with control groups. Taken together, these results suggest a role for miR‑145 as a tumor suppressor which inhibits glioma cell proliferation, invasion and angiogenesis in vitro and reduces glioma growth in vivo
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