358 research outputs found
Backstepping-Based Exponential Stabilization of Timoshenko Beam with Prescribed Decay Rate
This is an open access article under the CC BY-NC-ND license.In this paper, we present a rapid boundary stabilization of a Timoshenko beam with anti-damping and anti-stiffness at the uncontrolled boundary, by using PDE backstepping. We introduce a transformation to map the Timoshenko beam states into a (2+2) × (2+2) hyperbolic PIDE-ODE system. Then backstepping is applied to obtain a control law guaranteeing closed-loop stability of the origin in the H1 sense. Arbitrarily rapid stabilization can be achieved by adjusting control parameters. Finally, a numerical simulation shows that the proposed controller can rapidly stabilize the Timoshenko beam. This result extends a previous work which considered a slender Timoshenko beam with Kelvin-Voigt damping, allowing destabilizing boundary conditions at the uncontrolled boundary and attaining an arbitrarily rapid convergence rate
Effects of the Pinggan Qianyang Recipe on MicroRNA Gene Expression in the Aortic Tissue of Spontaneously Hypertensive Rats
The present study aimed to investigate the relationship between miRNAs and in spontaneously hypertensive rats (SHR) vascular remodeling and analyze the impact of the Pinggan Qianyang recipe (PQR) on miRNAs. Mammalian miRNA microarrays containing 509 miRNA genes were employed to analyze the differentially expressed miRNAs in the three groups. MiRNAs were considered to be up- or downregulated when the fluorescent intensity ratio between the two groups was over 4-fold. Validation of those miRNAs changed in SHR after PQR treatment was used by real-time quantitative RT-PCR (qRT-PCR). Compared with the normal group, a total of 32 miRNAs were differentially expressed by more than twofold; among these, 18 were upregulated and 14 were downregulated in the model group. Compared with the normal group, there were a number of 17 miRNAs which were significantly expressed by more than twofold in the different expressions of 32 miRNAs; among these, 10 were downregulated and 7 were upregulated in the PQR group. qRT-PCR verified that miR-20a, miR-145, miR-30, and miR-98 were significantly expressed in the three groups. These data show that PQR could exert its antihypertensive effect through deterioration of the vascular remodeling process. The mechanism might be associated with regulating differentially expressed miRNAs in aorta tissue
Comparison of Adjunctive Naoxintong versus Clopidogrel in Volunteers with the CYP2C19*2 Gene Mutation Accompanied with Qi Deficiency and Blood Stasis Constitution
This study was to determine the impact of adjunctive Buchang Naoxintong Jiaonang (BNJ) to clopidogrel on volunteers with the CYP2C19*2 gene mutation accompanied with qi deficiency and blood stasis (QDBS) constitution. Eighteen males with QDBS constitution were selected, who were 6 CYP2C19*1/*1, 6 CYP2C19*1/*2, and 6 CYP2C19*2/*2, and signed informed consent. Results showed that the maximal platelet aggregation (Aggmax) and 5 min aggregation (Agglate) with 5-μmol/L ADP in three different CYP2C19*2 genotypes were significantly decreased after any drug therapy compared with corresponding baseline measurements (all values P < .05). But percent inhibitions of Aggmax and Agglate (IPAs) in CYP2C19*2/*2 genotype at 4 hours, 24 hours, 3 days, and 7 days after clopidogrel administration were all the lowest among three CYP2C19*2 genotypes (P < .01), and IPAs in CYP2C19*1/*2 genotype were between CYP2C19*1/*1 and CYP2C19*2/*2. IPAs had no significant difference among three different CYP2C19*2 genotypes after BNJ or adjunctive BNJ. In addition, changes of CD62P, PAC1, and sCD40L were similar to changes of ADP-induced platelet aggregation in three different CYP2C19*2 genotypes. Conclusion was that adjunctive BNJ to clopidogrel can enhance the antiplatelet effect in volunteers with the CYP2C19*2 gene mutation
EWT: Efficient Wavelet-Transformer for Single Image Denoising
Transformer-based image denoising methods have achieved encouraging results
in the past year. However, it must uses linear operations to model long-range
dependencies, which greatly increases model inference time and consumes GPU
storage space. Compared with convolutional neural network-based methods,
current Transformer-based image denoising methods cannot achieve a balance
between performance improvement and resource consumption. In this paper, we
propose an Efficient Wavelet Transformer (EWT) for image denoising.
Specifically, we use Discrete Wavelet Transform (DWT) and Inverse Wavelet
Transform (IWT) for downsampling and upsampling, respectively. This method can
fully preserve the image features while reducing the image resolution, thereby
greatly reducing the device resource consumption of the Transformer model.
Furthermore, we propose a novel Dual-stream Feature Extraction Block (DFEB) to
extract image features at different levels, which can further reduce model
inference time and GPU memory usage. Experiments show that our method speeds up
the original Transformer by more than 80%, reduces GPU memory usage by more
than 60%, and achieves excellent denoising results. All code will be public.Comment: 12 pages, 11 figur
A Multifunctional Array System Based on Adjustable-Phase Antenna for Wireless communications
In this work, an innovative method for controlling the current distribution
of the radiating patch by adjusting the input phase is investigated to achieve
both pattern and polarization reconfigurable characteristics for the
multifunction. A compact and low-profile antenna with four fed ports is
designed to implement the proposed method, which can operate linear, right-hand
circular polarization (RHCP) and left-hand circular polarization (LHCP) with
different beam directions in the operating band from 4.0 to 5.0 GHz. Even more,
a four-by-four passive planar array is designed and fabricated based on this
antenna element, which can scan the coverage of 70{\deg} with low gain
fluctuation and low sidelobe with dual-polarization. Meanwhile, it can realize
the wide-angle scanning capability up to 60{\deg} with low sidelobe with RHCP
and LHCP. More important, the dual- and triple-beam with different directions
can be obtained by the proposed array. Good agreement has been shown between
measured and simulated results. Therefore, the proposed antenna is a good
solution for wireless communication systems because of its
simple-configuration, multifunction, and beamforming capability
Investigation of Wood Impact Properties Using Fractal Dimension Analysis
Fractal analysis is a research tool recently used to model various processes. However, this analysis has not been used for determining impact properties of wood. In this study, the transverse and longitudinal impact ductility of five species, ie white pine, poplar, pine, birch, and basswood, was experimentally determined. Based on the grid-cover method, photographs were taken of the fracture surfaces and edited by image graying using Photoshop CS5 (Adobe Systems Inc.). The yardstick δ was determined by adjusting the distance between the grid lines. The slope K of the regression equation of Log(1/δi) vs Log(N[δi]) was the fractal dimension DL of the fracture profile curve. Fractal dimension allows us to measure the complexity of fracture profiles after the specimens were broken by impacts. The results indicate that the average fractal dimension values were 2.023-2.075 on the fractures from transverse and longitudinal impacts. The longitudinal impact ductility was greater than the transverse for all tested species. The transverse and longitudinal impact ductility was linearly related to the fracture fractal dimension
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