222 research outputs found
Enhanced Gas-Flow-Induced Voltage in Graphene
We show by systemically experimental investigation that gas-flow-induced
voltage in monolayer graphene is more than twenty times of that in bulk
graphite. Examination over samples with sheet resistances ranging from 307 to
1600 {\Omega}/sq shows that the induced voltage increase with the resistance
and can be further improved by controlling the quality and doping level of
graphene. The induced voltage is nearly independent of the substrate materials
and can be well explained by the interplay of Bernoulli's principle and the
carrier density dependent Seebeck coefficient. The results demonstrate that
graphene has great potential for flow sensors and energy conversion devices
Content adaptive sparse illumination for Fourier ptychography
Fourier Ptychography (FP) is a recently proposed technique for large field of
view and high resolution imaging. Specifically, FP captures a set of low
resolution images under angularly varying illuminations and stitches them
together in Fourier domain. One of FP's main disadvantages is its long
capturing process due to the requisite large number of incident illumination
angles. In this letter, utilizing the sparsity of natural images in Fourier
domain, we propose a highly efficient method termed as AFP, which applies
content adaptive sparse illumination for Fourier ptychography by capturing the
most informative parts of the scene's spatial spectrum. We validate the
effectiveness and efficiency of the reported framework with both simulations
and real experiments. Results show that the proposed AFP could shorten the
acquisition time of conventional FP by around 30%-60%
MiR-379 inhibits proliferation and induces apoptosis in multiple myeloma by targeting Y-box binding protein 1
Purpose: To determine the effect of miR-379 in multiple myeloma.Methods: Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to evaluate the expression of miR-379 in multiple myeloma cells. The effect of miR-379 on multiple myeloma progression was investigated by cell counting, bromodeoxyuridine staining, flow cytometry and Western blot analysis. A potential target for miR-379 was determined using a luciferase reporter assay.Results: MiR-379 expression was reduced in multiple myeloma cells, while over-expression of miR-379 increased both cell viability and proliferation of these cells (p < 0.05). Moreover, miR-379 blocked cell cycle multiple myeloma cells and promoted apoptosis by decreasing Bcl-2 expression, and increasing the expression of cleaved caspase-3 and Bax. MiR-379 bound to Y-box binding protein 1 (YBX1) and reduced YBX1 mRNA and protein expression in multiple myeloma cells (p < 0.05).Conclusion: A YBX1-mediated tumor-suppressive role for miR-379 in multiple myeloma cells has been identified, suggesting a potential strategy for the treatment of multiple myeloma.
Keywords: MiR-379, Y-box binding protein 1, Multiple myeloma, Proliferation, Apoptosi
Motion-corrected Fourier ptychography
Fourier ptychography (FP) is a recently proposed computational imaging
technique for high space-bandwidth product imaging. In real setups such as
endoscope and transmission electron microscope, the common sample motion
largely degrades the FP reconstruction and limits its practicability. In this
paper, we propose a novel FP reconstruction method to efficiently correct for
unknown sample motion. Specifically, we adaptively update the sample's Fourier
spectrum from low spatial-frequency regions towards high spatial-frequency
ones, with an additional motion recovery and phase-offset compensation
procedure for each sub-spectrum. Benefiting from the phase retrieval redundancy
theory, the required large overlap between adjacent sub-spectra offers an
accurate guide for successful motion recovery. Experimental results on both
simulated data and real captured data show that the proposed method can correct
for unknown sample motion with its standard deviation being up to 10% of the
field-of-view scale. We have released our source code for non-commercial use,
and it may find wide applications in related FP platforms such as endoscopy and
transmission electron microscopy
Dynamic behaviors of 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle
Dynamic behaviors of the 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle is investigated. The telescopic mechanism is a combination of one vertical beam that can move axially, one constant beam perpendicularly fixed at the end of the vertical beam and one telescopic beam that can move along the axial direction of the constant beam during work. The Euler-Bernoulli beam theory is utilized to simplify the beams. The Lagrangian description is adopted to account for the coordinate for the telescopic mechanism. The equations of motion are derived using the Hamilton’s principle and decomposed into a set of ordinary differential equations by employing the Galerkin’s method. The eigenfunctions are acquired based on the boundary conditions by adopting the dichotomy method. The solutions to the equations are acquired using the Newmark-β method. Experiments are carried out to prove the validity of the theoretical model. Numerical examples are simulated to explore whether the vertical beam and telescopic beam can extend or retract synchronously and obtain appropriate beam moving strategy. The results prove that synchronous motion of the vertical beam and telescopic beam will not always lead to pronounced stronger vibration than the separate ones. On the other hand, the beam moving strategies that the telescopic beam moving before the vertical beam when they all extend out or retract back and moving after the vertical beam when one extends out and the other retracts back will effectively reduce the vibration compared with otherwise
Simulation of the lateral oscillation of rope-guided conveyance based on fluid-structure interaction
How to define the clearance between rope-guided conveyances and shaft wall reasonably has confused peers for more than one hundred years. In this paper, the fluid-structure interaction approach was used to simulate the lateral oscillations of rope-guided conveyances. With Yaoqiao vertical production shaft taken into account to validate this approach, user-defined functions coupled with ANSYS FLUENT were employed to conduct the two-dimensional numerical simulation, and the simulation results show that the lateral aerodynamic buffeting force when two conveyances pass each other is much larger than Coriolis force. What’s more important, with the lateral acceleration, velocity and displacement of the conveyances obtained, the simulation results can explain how the lateral aerodynamic buffeting force to oscillate the conveyance laterally successfully. This approach can be easily extended to three-dimensional simulations, to be more reasonable
Dynamic behaviors of 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle
Dynamic behaviors of the 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle is investigated. The telescopic mechanism is a combination of one vertical beam that can move axially, one constant beam perpendicularly fixed at the end of the vertical beam and one telescopic beam that can move along the axial direction of the constant beam during work. The Euler-Bernoulli beam theory is utilized to simplify the beams. The Lagrangian description is adopted to account for the coordinate for the telescopic mechanism. The equations of motion are derived using the Hamilton’s principle and decomposed into a set of ordinary differential equations by employing the Galerkin’s method. The eigenfunctions are acquired based on the boundary conditions by adopting the dichotomy method. The solutions to the equations are acquired using the Newmark-β method. Experiments are carried out to prove the validity of the theoretical model. Numerical examples are simulated to explore whether the vertical beam and telescopic beam can extend or retract synchronously and obtain appropriate beam moving strategy. The results prove that synchronous motion of the vertical beam and telescopic beam will not always lead to pronounced stronger vibration than the separate ones. On the other hand, the beam moving strategies that the telescopic beam moving before the vertical beam when they all extend out or retract back and moving after the vertical beam when one extends out and the other retracts back will effectively reduce the vibration compared with otherwise
Dynamic behaviors of 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle
Dynamic behaviors of the 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle is investigated. The telescopic mechanism is a combination of one vertical beam that can move axially, one constant beam perpendicularly fixed at the end of the vertical beam and one telescopic beam that can move along the axial direction of the constant beam during work. The Euler-Bernoulli beam theory is utilized to simplify the beams. The Lagrangian description is adopted to account for the coordinate for the telescopic mechanism. The equations of motion are derived using the Hamilton’s principle and decomposed into a set of ordinary differential equations by employing the Galerkin’s method. The eigenfunctions are acquired based on the boundary conditions by adopting the dichotomy method. The solutions to the equations are acquired using the Newmark-β method. Experiments are carried out to prove the validity of the theoretical model. Numerical examples are simulated to explore whether the vertical beam and telescopic beam can extend or retract synchronously and obtain appropriate beam moving strategy. The results prove that synchronous motion of the vertical beam and telescopic beam will not always lead to pronounced stronger vibration than the separate ones. On the other hand, the beam moving strategies that the telescopic beam moving before the vertical beam when they all extend out or retract back and moving after the vertical beam when one extends out and the other retracts back will effectively reduce the vibration compared with otherwise
Dynamic behaviors of 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle
Dynamic behaviors of the 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle is investigated. The telescopic mechanism is a combination of one vertical beam that can move axially, one constant beam perpendicularly fixed at the end of the vertical beam and one telescopic beam that can move along the axial direction of the constant beam during work. The Euler-Bernoulli beam theory is utilized to simplify the beams. The Lagrangian description is adopted to account for the coordinate for the telescopic mechanism. The equations of motion are derived using the Hamilton’s principle and decomposed into a set of ordinary differential equations by employing the Galerkin’s method. The eigenfunctions are acquired based on the boundary conditions by adopting the dichotomy method. The solutions to the equations are acquired using the Newmark-β method. Experiments are carried out to prove the validity of the theoretical model. Numerical examples are simulated to explore whether the vertical beam and telescopic beam can extend or retract synchronously and obtain appropriate beam moving strategy. The results prove that synchronous motion of the vertical beam and telescopic beam will not always lead to pronounced stronger vibration than the separate ones. On the other hand, the beam moving strategies that the telescopic beam moving before the vertical beam when they all extend out or retract back and moving after the vertical beam when one extends out and the other retracts back will effectively reduce the vibration compared with otherwise
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