939 research outputs found
Energy-Momentum Tensor and Related Experimental Analysis of Electromagnetic Waves in Media
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
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
A mixed graph is the graph obtained from an unoriented simple graph
by giving directions to some edges of , where is often called the
underlying graph of . In this paper, we introduce two classes of
incidence matrices of the second kind of , 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 .
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 .Comment: 16 pages,7 figure
Effects of Acupuncture on Th1, Th2 Cytokines in Rats of Implantation Failure
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
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(). 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
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 () 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
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.
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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