21,763 research outputs found
Recommended from our members
A Preliminary Study on Using Multi-Nozzle Polymer Deposition System to Fabricate Composite Alginate/Carbon Nanotube Tissue Scaffolds
Three-dimensional composite alginate/single wall carbon nanotube (SWCNT) scaffolds
encapsulated with endothelial cells were fabricated by a multi-nozzle biopolymer freeform
deposition system. This system enables the converting of CAD designed scaffold pattern into
process toolpaths and the use of computer control program to guide the nozzle deposition at
spatial position for layered fabrication of 3D tissue scaffolds. The morphological, mechanical,
structural and biological properties of as-fabricated scaffolds were characterized by optical
microscope, SEM, Microtensile testing machine, Alamar Blue Assay, and Live-Dead Assay,
respectively. The multi-nozzle deposition system demonstrated a highly efficient and effective
process to build tissue scaffold or cell embedded constructs. Characterization results showed that
the incorporation of SWCNT into alginate not only enhanced the mechanical strength of the
scaffolds but also improved the cell affinity and the interaction with substrate. Further cell
culture experimental results also showed that the incorporation of SWCNT in alginate enhanced
endothelial cell proliferation compared with pure alginate scaffold.Mechanical Engineerin
Universal Tomonaga-Luttinger liquid phases in one-dimensional strongly attractive SU(N) fermionic cold atoms
A simple set of algebraic equations is derived for the exact low-temperature
thermodynamics of one-dimensional multi-component strongly attractive fermionic
atoms with enlarged SU(N) spin symmetry and Zeeman splitting. Universal
multi-component Tomonaga-Luttinger liquid (TLL) phases are thus determined. For
linear Zeeman splitting, the physics of the gapless phase at low temperatures
belongs to the universality class of a two-component asymmetric TLL
corresponding to spin-neutral N-atom composites and spin-(N-1)/2 single atoms.
The equation of states is also obtained to open up the study of multi-component
TLL phases in 1D systems of N-component Fermi gases with population imbalance.Comment: 12 pages, 3 figure
LDA Characterization of the Velocity Field around a Growing and Rising Bubble in Shear-thinning Fluid
Laser Doppler anemometry (LDA) has been employed to quantify the liquid velocity field around a single bubble in its generating and accelerating stage in carboxymethylcellulose (CMC) aqueous solution. The instantanoues velocities were treated by Reynolds time-averaged method, and mean velocities and its contours in both axial and radial directions were investigated. The results show that in vertical direction, the flow field characteristics of the liquids around the bubble are determined by bubble formation-rise mechanism, whereas in horizontal direction they are governed by the relative position with the bubble shear radius. The contours of axial and radial mean velocity in the test section take on the shapes of inverted trapezoid and butterfly forewing, respectively
Seismic performance analysis of blast furnace shell structure
In this paper, the finite element software ANSYS is used to establish a three-dimensional space model of the blast furnace shell, and the static analysis of the space steel structure system of the blast furnace is carried out. The seismic response of the outer shell system of the blast furnace is analyzed by response spectrum method and linear time history analysis method, so as to explore the seismic response of the blast furnace shell
Seismic performance analysis of blast furnace shell structure
In this paper, the finite element software ANSYS is used to establish a three-dimensional space model of the blast furnace shell, and the static analysis of the space steel structure system of the blast furnace is carried out. The seismic response of the outer shell system of the blast furnace is analyzed by response spectrum method and linear time history analysis method, so as to explore the seismic response of the blast furnace shell
Exactly solvable models and ultracold Fermi gases
Exactly solvable models of ultracold Fermi gases are reviewed via their
thermodynamic Bethe Ansatz solution. Analytical and numerical results are
obtained for the thermodynamics and ground state properties of two- and
three-component one-dimensional attractive fermions with population imbalance.
New results for the universal finite temperature corrections are given for the
two-component model. For the three-component model, numerical solution of the
dressed energy equations confirm that the analytical expressions for the
critical fields and the resulting phase diagrams at zero temperature are highly
accurate in the strong coupling regime. The results provide a precise
description of the quantum phases and universal thermodynamics which are
applicable to experiments with cold fermionic atoms confined to one-dimensional
tubes.Comment: based on an invited talk at Statphys24, Cairns (Australia) 2010. 16
pages, 6 figure
Wilson ratio of Fermi gases in one dimension
We calculate the Wilson ratio of the one-dimensional Fermi gas with spin
imbalance. The Wilson ratio of attractively interacting fermions is solely
determined by the density stiffness and sound velocity of pairs and of excess
fermions for the two-component Tomonaga-Luttinger liquid (TLL) phase. The ratio
exhibits anomalous enhancement at the two critical points due to the sudden
change in the density of states. Despite a breakdown of the quasiparticle
description in one dimension, two important features of the Fermi liquid are
retained, namely the specific heat is linearly proportional to temperature
whereas the susceptibility is independent of temperature. In contrast to the
phenomenological TLL parameter, the Wilson ratio provides a powerful parameter
for testing universal quantum liquids of interacting fermions in one, two and
three dimensions.Comment: 5+2 pages, 4+1 figures, Eq. (4) is proved, figures were refine
Effective renormalized multi-body interactions of harmonically confined ultracold neutral bosons
We calculate the renormalized effective 2-, 3-, and 4-body interactions for N
neutral ultracold bosons in the ground state of an isotropic harmonic trap,
assuming 2-body interactions modeled with the combination of a zero-range and
energy-dependent pseudopotential. We work to third-order in the scattering
length a defined at zero collision energy, which is necessary to obtain both
the leading-order effective 4-body interaction and consistently include
finite-range corrections for realistic 2-body interactions. The leading-order,
effective 3- and 4-body interaction energies are U3 = -(0.85576...)(a/l)^2 +
2.7921(1)(a/l)^3 + O[(a/l)^4] and U4 = +(2.43317...)(a/l)^3 + O[(a\l)^4], where
w and l are the harmonic oscillator frequency and length, respectively, and
energies are in units of hbar*w. The one-standard deviation error 0.0001 for
the third-order coefficient in U3 is due to numerical uncertainty in estimating
a slowly converging sum; the other two coefficients are either analytically or
numerically exact. The effective 3- and 4-body interactions can play an
important role in the dynamics of tightly confined and strongly correlated
systems. We also performed numerical simulations for a finite-range boson-boson
potential, and it was comparison to the zero-range predictions which revealed
that finite-range effects must be taken into account for a realistic
third-order treatment. In particular, we show that the energy-dependent
pseudopotential accurately captures, through third order, the finite-range
physics, and in combination with the multi-body effective interactions gives
excellent agreement with the numerical simulations, validating our theoretical
analysis and predictions.Comment: Updated introduction, correction of a few typos and sign error
Universal local pair correlations of Lieb-Liniger bosons at quantum criticality
The one-dimensional Lieb-Liniger Bose gas is a prototypical many-body system
featuring universal Tomonaga-Luttinger liquid (TLL) physics and free fermion
quantum criticality. We analytically calculate finite temperature local pair
correlations for the strong coupling Bose gas at quantum criticality using the
polylog function in the framework of the Yang-Yang thermodynamic equations. We
show that the local pair correlation has the universal value in the quantum critical regime, the TLL phase and the
quasi-classical region, where is the pressure per unit length rescaled by
the interaction energy with interaction
strength and linear density . This suggests the possibility to test
finite temperature local pair correlations for the TLL in the relativistic
dispersion regime and to probe quantum criticality with the local correlations
beyond the TLL phase. Furthermore, thermodynamic properties at high
temperatures are obtained by both high temperature and virial expansion of the
Yang-Yang thermodynamic equation.Comment: 8 pages, 6 figures, additional text and reference
- …