39 research outputs found

    Image Deblurring via an Adaptive Dictionary Learning Strategy

    Get PDF
    Recently, sparse representation has been applied to image deblurring. The dictionary is the fundamental part of it and the proper selection of dictionary is very important to achieve super performance. The global learned dictionary might achieve inferior performances since it could not mine the specific information such as the texture and edge which is contained in the blurred image. However, it is a computational burden to train a new dictionary for image deblurring which requires the whole image (or most parts) as input; training the dictionary on only a few patches would result in over-fitting. To address the problem, we instead propose an online adaption strategy to transfer the global learned dictionary to a specific image. In our deblurring algorithm, the sparse coefficients, latent image, blur kernel and the dictionary are updated alternatively. And in every step, the global learned dictionary is updated in an online form via sampling only a few training patches from the target noisy image. Since our adaptive dictionary exploits the specific information, our deblurring algorithm shows superior performance over other state-of-the-art algorithms.

    Study on dynamic characteristics of double cylinder double acting bilge pump transmission

    Get PDF
    In view of the complex structure of the ship bilge pump, the excitation source in the process of work is difficult to accurately determine the fault condition of the bilge pump through the vibration test data. Based on the theory of multi - body dynamics, rotor dynamics and electrical mechanics, the kinematics and kinetic equations of the bilge pump drive are established, and the dynamics, kinematics and vibration characteristics of bottom Pump drive analysis of the cabin is carried out. The frequency of the excitation force corresponding to the transmission mechanism is deduced, and the frequency of the excitation force of the main transmission is calculated

    Finite edge-transitive dihedrant graphs

    Get PDF
    AbstractIn this paper, we first prove that each biquasiprimitive permutation group containing a regular dihedral subgroup is biprimitive, and then give a classification of such groups. The classification is then used to classify vertex-quasiprimitive and vertex-biquasiprimitive edge-transitive dihedrants. Moreover, a characterization of valencies of normal edge-transitive dihedrants is obtained, and some classes of examples with certain valences are constructed

    Analysis of Pollution in Dianchi Lake and Consideration of Its Application in Crop Planting

    Get PDF
    AbstractAfter investigating the distribution and composition of N-cycle-related bacteria of different sites and different depth of Dianchi sediment, we analyzed the longitudinal distribution, lateral distribution of N, its transportation and transformation in Dianchi sediment, as well as the involvement of these bacteria in nitrogen cycle. Conclusion was drawn as follows, (1) Azotobateria could be effectively used as indicative strains to track the changes of Dianchi pollution because the distribution of Azotobateria can not only indicate N contamination but also P enrichment, (2) ammoniate and nitrite is mainly existed in top sediment of Dianchi Lake while other forms of nitrogen mainly in deeper sediment, (3) due to the fact that Dianchi is rich in P, together with the mutual promotion between N pollution and P pollution, the pollution of south part will worsen rapidly, (4) if the south part is also polluted badly, the pollution distribution will appear as peaking at both ends (north and south), and the pollution will definitely extend toward the middle, and finally Dianchi Lake will totally be seriously polluted. Combining with the fact that 40% of Dianchi pollution was caused by abusive use of chemical fertilizer, we put forward the idea of “changing pollutants into things of value”, which could be specified as “using the sediment as agricultural fertilizer”. Such method can solve the problem of internal pollution, and what's more, it can develop agriculture, while cut down the use of chemical fertilizer and thus reduce relative pollution source

    Schrodinger cat states prepared by Bloch oscillation in a spin-dependent optical lattice

    Full text link
    We propose to use Bloch oscillation of ultra-cold atoms in a spin-dependent optical lattice to prepare schrodinger cat states. Depending on its internal state, an atom feels different periodic potentials and thus has different energy band structures for its center-of-mass motion. Consequently, under the same gravity force, the wave packets associated with different internal states perform Bloch oscillation of different amplitudes in space and in particular they can be macroscopically displaced with respect to each other. In this way, a cat state can be prepared.Comment: 4 pages, 3 figures; slightly modifie

    Co-optimization method to improve lateral resolution in photoacoustic computed tomography

    Get PDF
    In biomedical imaging, photoacoustic computed tomography (PACT) has recently gained increased interest as this imaging technique has good optical contrast and depth of acoustic penetration. However, a spinning blur will be introduced during the image reconstruction process due to the limited size of the ultrasonic transducers (UT) and a discontinuous measurement process. In this study, a damping UT and adaptive back-projection co-optimization (CODA) method is developed to improve the lateral spatial resolution of PACT. In our PACT system, a damping aperture UT controls the size of the receiving area, which suppresses image blur at the signal acquisition stage. Then, an innovative adaptive back-projection algorithm is developed, which corrects the undesirable artifacts. The proposed method was evaluated using agar phantom and ex-vivo experiments. The results show that the CODA method can effectively compensate for the spinning blur and eliminate unwanted artifacts in PACT. The proposed method can significantly improve the lateral spatial resolution and image quality of reconstructed images, making it more appealing for wider clinical applications of PACT as a novel, cost-effective modality

    Label-free sensing below the sub-diffraction limit of virus-like particles by wide-field photon state parametric imaging of a gold nanodot array

    Get PDF
    A parallel four-quadrant sensing method utilizing a specially designed gold nanodot array is created for sensing virus-like particles with sub-diffraction limit size (~100 nm) in a wide-field image. Direct label-free sensing of virus using multiple four-quadrant sensing channel in parallel in a wide-field view enables the possibility of high-throughput onsite screening of virus

    A Study of Polycrystalline Silicon Damage Features Based on Nanosecond Pulse Laser Irradiation with Different Wavelength Effects

    No full text
    Based on PVDF (piezoelectric sensing techniques), this paper attempts to study the propagation law of shock waves in brittle materials during the process of three-wavelength laser irradiation of polysilicon, and discusses the formation mechanism of thermal shock failure. The experimental results show that the vapor pressure effect and the plasma pressure effect in the process of pulsed laser irradiation lead to the splashing of high temperature and high density melt. With the decrease of the laser wavelength, the laser breakdown threshold decreases and the shock wave is weakened. Because of the pressure effect of the laser shock, the brittle fracture zone is at the edge of the irradiated area. The surface tension gradient and surface shear wave caused by the surface wave are the result of coherent coupling between optical and thermodynamics. The average propagation velocity of laser shock wave in polysilicon is 8.47 Ă— 103 m/s, and the experiment has reached the conclusion that the laser shock wave pressure peak exponentially distributes attenuation in the polysilicon

    Preparation of Microstructure Laser Ablation and Multiple Acid-Etching Composites on the Surfaces of Medical Titanium Alloy TC4 by Laser Ablation and Multiple Acid-Etching, and Study of Frictional Properties of the Processed Surfaces

    No full text
    In this paper, four array patterns were first designed by observing the structural features of the surface microstructures of pig bones and tree frog paws on the titanium alloy surface bionically. Then, the optimal parameters for laser processing were determined experimentally, and the optimized processing parameters were used to prepare micron-scale bumps on the titanium alloy surface and to investigate the relationship between the weaving height and the processing times. Finally, multiple acid etching was used to prepare nanoscale holes on the surface of the titanium alloy. It was found that the multiple acid etching could not only prepare nanoscale holes on the surface of the titanium alloy, but could also well eliminate the slag left on the surface of titanium alloy by laser ablation. Based on the above study, this paper also analyzed the effect of micro-nano structure on the friction properties of the titanium alloy surface from three aspects—theory, hardness test and friction coefficient test—and experimentally analyzed the effect of single-factor and multi-factor coupling of structural features on the friction properties of the titanium alloy surface. It was found that the optimal mean friction coefficient was 0.0902, corresponding to the characteristic values of 0.66 for the shape, 200 μm for the edge length and 60 μm for the height

    Bivalent Ligands Targeting Multiple Pathological Factors Involved in Alzheimer's Disease

    No full text
    In a continuing effort to develop multifunctional compounds as potential treatment agents for Alzheimer's disease (AD), a series of bivalent ligands containing curcumin and cholesterylamine were designed, synthesized, and biologically characterized. Biological characterization supported earlier results that the spacer length and its attachment position on curcumin are essential structural determinants for biological activity in this class. Compounds with a spacer length of 17–21 atoms exhibited optimal neuroprotection in human neuroblastoma MC65 cells with submicromolar potency. These compounds inhibited the formation of amyloid-β oligomers (AβOs) and exhibited antioxidative activities in MC65 cells. Bivalent ligand <b>8</b>, with its spacer (length of 17 atoms) connected at the methylene carbon between the two carbonyls of the curcumin moiety, is the most potent with an EC<sub>50</sub> of 0.083 ± 0.017 μM. In addition, <b>8</b> formed a complex with biometals, such as Cu, Fe, and Zn. Collectively, the results strongly support our assertion that these compounds are designed bivalent ligands with potential as multifunctional and neuroprotective agents
    corecore