939 research outputs found

    Energy-Momentum Tensor and Related Experimental Analysis of Electromagnetic Waves in Media

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    We find that the energy-momentum tensor of electromagnetic waves in media is very similar to that of ordinary fluids, and concepts such as density, pressure, and energy transfer rate can be similarly defined. On this basis, we conducted a detailed theoretical analysis on the mean momentum and equivalent mass of photons in the medium, the relationship between pressure and polarization of beams, the influence of polarization energy and magnetization energy of the medium, the Bernoulli effect of beams and the energy-momentum tensor of beams in moving media. We also obtain a conservation new energy-momentum tensor based on the interaction term between the electromagnetic field and the medium. From this energy-momentum tensor, we can derive both the Minkowski momentum and the Abraham momentum simultaneously. We find that Minkowski momentum is actually a canonical momentum that considers the influence of the interaction between electromagnetic waves and media, while Abraham momentum is actually a mechanical momentum that does not consider the influence of the interaction between electromagnetic waves and media. Based on the theory obtained in this paper, we have provided theoretical explanations for Jones'experiment of light pressure in a medium, Ashkin's free liquid surface deformation experiment, Weilong's optical fiber deformation experiment, and frequency shift measurement experiment. The theory obtained in this paper can self-consistently explain the above experiments simultaneously. Unlike the Minkowski and Abraham tensors, according to the energy-momentum tensor proposed in this paper, a beam in a medium also generates a pressure on its side, and the direction of this pressure is related to the polarization of the beam. The findings of this paper may shed new light on the application of light.Comment: Page 29, Figure

    Fantastic Behavior of High-TC Superconductor Junctions: Tunable Superconductivity

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    Carrier injection performed in oxygen-deficient YBa2Cu3O7(YBCO) hetero-structure junctions exhibited tunable resistance that was entirely different with behaviors of semiconductor devices. Tunable superconductivity in YBCO junctions, increasing over 20 K in transition temperature, has achieved by using electric processes. To our knowledge, this is the first observation that intrinsic property of high TC superconductors superconductivity can be adjusted as tunable functional parameters of devices. The fantastic phenomenon caused by carrier injection was discussed based on a proposed charge carrier self-trapping model and BCS theory.Comment: 5 pages, 4 figure

    More on minors of Hermitian (quasi-)Laplacian matrix of the second kind for mixed graphs

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    A mixed graph MGM_{G} is the graph obtained from an unoriented simple graph GG by giving directions to some edges of GG, where GG is often called the underlying graph of MGM_{G}. In this paper, we introduce two classes of incidence matrices of the second kind of MGM_{G}, and discuss the determinants of these two matrices for rootless mixed trees and unicyclic mixed graphs. Applying these results, we characterize the explicit expressions of various minors for Hermitian (quasi-)Laplacian matrix of the second kind of MGM_{G}. Moreover, we give two sufficient conditions that the absolute values of all the cofactors of Hermitian (quasi-)Laplacian matrix of the second kind are equal to the number of spanning trees of the underlying graph GG.Comment: 16 pages,7 figure

    Effects of Acupuncture on Th1, Th2 Cytokines in Rats of Implantation Failure

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    The aim is to explore the effect of acupuncture on Th1, Th2 cytokines in rats of implantation failure. Early pregnant rats were randomized into normal group (N), implantation failure group (M), acupuncture group (A), progestin group (H). The model was established with mifepristone. Samples of serum, endometrium were collected on Day 5, 6 and 8 of pregnancy. Compared with group M, the number of embryos was significantly higher in groups N, A and H; IL-1β, IL-2 protein in serum and endometrium were significantly lower in groups N, A and H, while IL-4, IL-10 were significantly higher in groups N, A and H; the endometrial IL-2, IL-4 mRNA were significantly lower in groups N, A and H, while IL-1β, IL-10 mRNA were significantly higher in groups N, A and H. Acupuncture could improve the poor receptive state of endometrium due to mifepristone by promoting Th2 cytokines secretion and inhibiting Th1 cytokines to improve blastocyst implantation

    Diffuse emission of TeV Neutrinos and Gamma-rays from young pulsars by Photo-meson interaction in the galaxy

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    It's generally believed that young and rapidly rotating pulsars are important sites of particle's acceleration, in which protons can be accelerated to relativistic energy above the polar cap region if the magnetic moment is antiparallel to the spin axis(μΩ<0\vec{\mu}\cdot\vec{\Omega}<0). To obtain the galactic diffusive neutrinos and gamma-rays for TeV, firstly,we use Monte Carlo(MC) method to generate a sample of young pulsars with ages less than 10610^6 yrs in our galaxy ; secondly, the neutrinos and high-energy gamma-rays can be produced through photomeson process with the interaction of energetic protons and soft X-ray photons (p+γΔ+n+π+/p+π0p+\gamma\rightarrow \Delta^+\rightarrow n+\pi^+/p+\pi^0) for single pulsar, and these X-ray photons come from the neutron star surface. The results suggest that the diffusive TeV flux of neutrinos are lower than background flux, which indicated it is difficult to be detected by the current neutrino telescopes.Comment: 11pages,6figures. arXiv admin note: text overlap with arXiv:0812.1845 by other author

    InterDiff: Generating 3D Human-Object Interactions with Physics-Informed Diffusion

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    This paper addresses a novel task of anticipating 3D human-object interactions (HOIs). Most existing research on HOI synthesis lacks comprehensive whole-body interactions with dynamic objects, e.g., often limited to manipulating small or static objects. Our task is significantly more challenging, as it requires modeling dynamic objects with various shapes, capturing whole-body motion, and ensuring physically valid interactions. To this end, we propose InterDiff, a framework comprising two key steps: (i) interaction diffusion, where we leverage a diffusion model to encode the distribution of future human-object interactions; (ii) interaction correction, where we introduce a physics-informed predictor to correct denoised HOIs in a diffusion step. Our key insight is to inject prior knowledge that the interactions under reference with respect to contact points follow a simple pattern and are easily predictable. Experiments on multiple human-object interaction datasets demonstrate the effectiveness of our method for this task, capable of producing realistic, vivid, and remarkably long-term 3D HOI predictions.Comment: ICCV 2023; Project Page: https://sirui-xu.github.io/InterDiff

    Radioprotective effect of lidocaine on neurotransmitter agonist-induced secretion in irradiated salivary glands.

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    Previously we verified the radioprotective effect of lidocaine on the function and ultrastructure of salivary glands in rabbits. However, the underlying mechanism of lidocaine's radioprotective effect is unknown. We hypothesized that lidocaine, as a membrane stabilization agent, has a protective effect on intracellular neuroreceptor-mediated signaling and hence can help preserve the secretory function of salivary glands during radiotherapy. Rabbits were irradiated with or without pretreatment with lidocaine before receiving fractionated radiation to a total dose of 35 Gy. Sialoscintigraphy and saliva total protein assay were performed before radiation and 1 week after the last radiation fraction. Isolated salivary gland acini were stimulated with either carbachol or adrenaline. Ca(2+) influx in response to the stimulation with these agonists was measured using laser scanning confocal microscopy. The uptake of activity and the excretion fraction of the parotid glands were significantly reduced after radiation, but lidocaine had a protective effect. Saliva total protein concentration was not altered after radiation. For isolated acini, Ca(2+) influx in response to stimulation with carbachol, but not adrenaline, was impaired after irradiation; lidocaine pretreatment attenuated this effect. Lidocaine has a radioprotective effect on the capacity of muscarinic agonist-induced water secretion in irradiated salivary glands
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