30 research outputs found

    Experimental study on vibration behavior of rotating manipulator in the process of scramming

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    In order to study the vibration behavior of rotating manipulator in the process of scramming, an experimental test is conducted on the vibration behavior during the process on different initial and measuring conditions. Through the experimental test, the vibration behavior exists two impact phenomena, which are found in the scramming process, and the feature extraction of the two impact phenomena is investigated. The dynamics parameters of the rotating manipulator are identified and hammer experiment is done to verify the dynamics parameters. With these parameters, an envelope model of the second impact response is established, and the applicability of the model is validated by experiments. The method of pasting damping layer on the surface of manipulator is employed to inhibit the vibration which is caused by the first impact. Via the experimental verification, the damping layer takes a certain effect on the vibration elimination

    Experimental study on vibration behavior of rotating manipulator in the process of scramming

    Get PDF
    In order to study the vibration behavior of rotating manipulator in the process of scramming, an experimental test is conducted on the vibration behavior during the process on different initial and measuring conditions. Through the experimental test, the vibration behavior exists two impact phenomena, which are found in the scramming process, and the feature extraction of the two impact phenomena is investigated. The dynamics parameters of the rotating manipulator are identified and hammer experiment is done to verify the dynamics parameters. With these parameters, an envelope model of the second impact response is established, and the applicability of the model is validated by experiments. The method of pasting damping layer on the surface of manipulator is employed to inhibit the vibration which is caused by the first impact. Via the experimental verification, the damping layer takes a certain effect on the vibration elimination

    The Second Monocular Depth Estimation Challenge

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    This paper discusses the results for the second edition of the Monocular Depth Estimation Challenge (MDEC). This edition was open to methods using any form of supervision, including fully-supervised, self-supervised, multi-task or proxy depth. The challenge was based around the SYNS-Patches dataset, which features a wide diversity of environments with high-quality dense ground-truth. This includes complex natural environments, e.g. forests or fields, which are greatly underrepresented in current benchmarks. The challenge received eight unique submissions that outperformed the provided SotA baseline on any of the pointcloud- or image-based metrics. The top supervised submission improved relative F-Score by 27.62%, while the top self-supervised improved it by 16.61%. Supervised submissions generally leveraged large collections of datasets to improve data diversity. Self-supervised submissions instead updated the network architecture and pretrained backbones. These results represent a significant progress in the field, while highlighting avenues for future research, such as reducing interpolation artifacts at depth boundaries, improving self-supervised indoor performance and overall natural image accuracy.Comment: Published at CVPRW202

    Research on Stochastic Resonance Detection Method for Periodic Signals under Low SNR and α-Stable Noise

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    In Dual Sequence Frequency Hopping (DSFH) communication mode, aiming at improving the detection performance to weak signal under low signal-to-noise ratio (SNR) conditions, stochastic resonance (SR) detection method is proposed. First, the α-stable distribution is used as the impulsive noise model and the influence of α value on the properties of α-stable noise is analyzed. Second, the transmitting and receiving signal model of DSFH communication system is introduced. The SR method is used to detect DSFH signal. In order to analyze the output signal, the fractional Fokker–Planck equation (FFPE) is established, and a new simplified solution method based on sampling decision time is proposed to solve the time-varying fractional differential equation. Base on the theoretical solution of FFPE, a binary hypothesis test statistic is constructed to quantify the signal detection probability and false alarm probability, and the detection performance is analyzed. Finally, simulation experiments verify the theoretical conclusions. The minimum effective SNR for SR detection is obtained, and it is about −20 dB, which provides a theoretical basis for the application of SR in the DSFH communication system

    Towards 3D Scene Reconstruction from Locally Scale-Aligned Monocular Video Depth

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    Existing monocular depth estimation methods have achieved excellent robustness in diverse scenes, but they can only retrieve affine-invariant depth, up to an unknown scale and shift. However, in some video-based scenarios such as video depth estimation and 3D scene reconstruction from a video, the unknown scale and shift residing in per-frame prediction may cause the depth inconsistency. To solve this problem, we propose a locally weighted linear regression method to recover the scale and shift with very sparse anchor points, which ensures the scale consistency along consecutive frames. Extensive experiments show that our method can boost the performance of existing state-of-the-art approaches by 50% at most over several zero-shot benchmarks. Besides, we merge over 6.3 million RGBD images to train strong and robust depth models. Our produced ResNet50-backbone model even outperforms the state-of-the-art DPT ViT-Large model. Combining with geometry-based reconstruction methods, we formulate a new dense 3D scene reconstruction pipeline, which benefits from both the scale consistency of sparse points and the robustness of monocular methods. By performing the simple per-frame prediction over a video, the accurate 3D scene shape can be recovered.Comment: 22 page

    Electrooxidation of Methanol on Pt @Ni Bimetallic Catalyst Supported on Porous Carbon Nanofibers

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    This paper describes the preparation of Ni/Pt/CNFs via electrospinning technology, carbonization process, and chemical reduction method. The structure and composition of Ni/Pt/CNFs were characterized with X-ray diffraction, Raman spectroscopy, nitrogen adsorption isotherms, and X-ray photoelectron spectroscopy. Meanwhile, the morphology was analyzed with scanning electron microscopy and transmission electron microscopy. The electrochemical performance was evaluated by oxygen reduction reaction (ORR), cyclic voltammetry and chronopotentiometry. The results indicated that Pt and Ni nanoparticles were completely reduced in the experimental process and homogeneously distributed on the nanofibers with the average diameters of 3.8 and 17.8 nm, respectively. In addition, the Ni<sub>50</sub>/Pt/CNFs catalyst showed excellent electrocatalytic performance for ORR and superior specific and mass activities for methanol oxidation (the maximum current density is ca. 10.9 mA cm<sup>–2</sup>) and exhibited a slightly slower current decay over time, better than the reference samples which indicated a higher tolerance to CO-like intermediates

    A novel MIP gene mutation analysis in a Chinese family affected with congenital progressive punctate cataract.

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    Congenital cataracts are one of the leading causes of visual impairment and blindness in children, and genetic factors play an important role in their development. This study aimed to identify the genetic defects associated with autosomal dominant congenital progressive punctate cataracts in a Chinese family and to explore the potential pathogenesis. Detailed family history and clinical data were recorded, and all the family members' blood samples were collected for DNA extraction. Linkage analysis was performed by microsatellite markers that are associated with punctate cataracts, and logarithm (base 10) of odds (LOD) scores were calculated using the LINKAGE program. Positive two-point LOD scores were obtained at markers D12S1622 (Zmax = 2.71 at θ = 0.0), D12S1724 (Zmax = 2.71 at θ = 0.0), and D12S90 (Zmax = 2.71 at θ = 0.0), which flank the major intrinsic protein of lens fiber (MIP) gene on chromosomal region 12q13. Direct sequencing of the encoding region of the MIP gene revealed a novel mutation (G>D) in exon 4 at nucleotide 644, which caused a substitution of glycine to aspartic acid at codon 215 (p.G215D) for the MIP protein. The mutation cosegregated with all patients with congenital progressive punctate cataracts, but it was absent in the healthy members. Bioinformatics analysis predicted that the mutation affects the function of the MIP protein. The wild type (WT) and G215D mutant of MIP were transfected with green fluorescent protein (GFP) into Hela cells separately, and it was found that the G215D mutant was aberrantly located in the cytoplasm instead of in the plasma membrane. In summary, our study presented genetic and functional evidence linking the new MIP mutation of G215D to autosomal dominant congenital cataracts, which adds to the list of MIP mutations linked to congenital progressive punctate cataracts

    Rational Design of Insecticidal Isoxazolines Containing Sulfonamide or Sulfinamide Structure as Antagonists of GABA Receptors with Reduced Toxicities to Honeybee and Zebrafish

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    To develop highly effective, nontarget organism-friendly insecticides based on the isoxazoline scaffold, we rationally designed and synthesized 25 isoxazoline derivatives containing sulfonamides and sulfinamides. Their insecticidal activities against the diamondback moth (Plutella xylostella), fall armyworm (Spodoptera frugiperda), beet armyworm (Spodoptera exigua), and Spodoptera litura Fabricius (S. litura) were evaluated. The trifluoromethyl sulfinamide-containing compound 7w displayed excellent activities with LC50 values being 0.09, 0.84, 0.87, and 0.68 mg/L against P. xylostella, S. frugiperda, S. exigua, and S. litura, respectively, which were superior to fluxametamide (LC50 = 0.09, 1.24, 1.10, and 0.65 mg/L, respectively) and maintained at the same order of magnitude LC50 values as fluralaner (LC50 = 0.02, 0.17, 0.12, and 0.19 mg/L, respectively). Importantly, compound 7w showed a medium toxicity level of acute toxicity to honeybee (LD50 = 2.22 μg/adult), which is significantly lower than the fluralaner (high toxicity level, LD50 = 0.09 μg/adult). Acute toxicity experiments with zebrafish (Danio rerio) indicated that compound 7w was safe with the LC50 value being 42.4 mg/L (low toxicity level). Furthermore, electrophysiological experiments and molecular docking studies preliminarily verified that compound 7w acts on the insect GABA receptor, and the theoretical calculations explained that the sulfinamide structure may play an important role in exhibiting biological activities. The above results suggest that compound 7w could be employed as a potentially highly effective, environmentally friendly insecticide to control multiple agricultural pests

    Pedigree of the family with autosomal dominant congenital progressive punctate cataracts.

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    <p>A three-generation pedigree with 16 members is shown. Squares and circles indicate males and females, respectively. Shaded shapes indicate affected individuals. The arrow indicates the proband.</p

    The protein levels of WT-MIP and G215D-MIP.

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    <p>Western blot analysis indicating that the mutation did not result in the expression or instability of the protein.</p
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