Research on Electromagnetic Force of Hybrid Electromagnetic Levitation Needle Driving System

Hybrid electromagnetic levitation drive system is the core of the needle drive structure, and its performance directly determines the size of the needle drive force. According to the initial design results, the simulation model of the needle drive is established in the electromagnetic field simulation software Maxwell, and the influence of the structural parameters of the hybrid electromagnetic drive system:, the material of the iron core, the number of coil turns on its static characteristics is analyzed. The simulation results show that at the same height, when the isolation ring material is aluminum, the time for the permanent magnet needle to rise to the highest position is the shortest.

Tree Rings Show Record of Newly Identified Extreme Solar Activity Event

Mass spectroscopy of tree ring material indicates a sharp, single-year rise in carbon-14 concentrations consistent with an extreme solar energetic particle event that occurred around 5410 BCE.

Possible case of exoplanetary rings around HIP 41378 f

<p>Planetary rings are exciting features yet to be detected around exoplanets despite their prevalence around the giant planets and other rocky bodies of the solar system. A number of studies have proposed methods to identify and characterise the signatures of rings mostly from transit light curves. Probing for the presence of rings in transit light curves is very useful as the rings can cause a number of effects both on the light curve shape and the inferred parameters of the planet.</p> <p>The presence of rings around a transiting planet can cause it to appear larger and lead to an underestimation of its density if the mass is known. Therefore, a class of planets with extremely low densities, called Super puffs, can be planets with yet undetected rings. A Bayesian framework is employed here to show that the anomalously low density (~0.09 g/cm<sup>3</sup>) of the transiting long-period planet HIP 41378f might be due to the presence of opaque circum-planetary rings. Analysing the light curve data from the K2 mission, we construct physically motivated model priors and found that the statistical evidence for the ringed planet scenario is  comparable to that of the planet-only scenario. The ringed planet solution suggests a larger planetary density of ~1.23 g/cm<sup>3</sup> similar to Uranus. The associated ring extends from 1.05 to 2.59 times the planetary radius and is inclined away from the sky-plane by ~25 degrees. However, the computed ring material density is lower than is expected for a planet with an equilibrium temperature of 294K so future high-precision transit observations of HIP 41378f would be necessary to confirm/dismiss the presence of planetary rings.</p>

Sizes of Particles, Clumps, and Gaps Within the Strong Janus 2:1 and Mimas 5:3 Density Waves from Cassini UVIS Stellar Occultation Data Statistics

<p>The high-speed photometer of Cassini’s Ultraviolet Imaging Spectrograph (UVIS) collected data from stellar occultations across Saturn’s rings at unprecedented high resolution over a wide range of viewing geometries. Because photon counts are described by Poisson statistics, we expect a variance equal to the mean in the absence of intervening ring material. However, most ring ‘particles’ are truly aggregates of smaller particles, ranging from micron-size dust to tens of meter-sized boulders, and if the sizes of these aggregates are not small relative to the field-of-view over a single integration period, they introduce excess variance from which we can glean further information about the sizes of particles and clumps. This is particularly relevant in the A ring, where non-axisymmetric self-gravity wakes are ubiquitous. Larger elongated clumps nicknamed straw have been directly imaged in the troughs of strong density waves (Porco et al., 2005, Science, 307, 1226-1236). In this work we present a survey of the statistical moments of variance and skewness for several ring stellar occultations at two strong density waves from different ring regions, Janus 2:1 and Mimas 5:3, over a variety of viewing angles. The line-of-sight distance from Cassini to the rings affects the measurement area due to the scattered signal and diffraction, and different viewing angles provide measurements of the same ring material with different aspects to potentially reveal the three-dimensional structure of clumps. We calculate an effective particle size per integration area, R, derived by Colwell et al., (2018, Icarus, 300, 150-166) and find similar values for R in both peaks and troughs across density waves as well as within density waves and in adjacent regions. We observe strong statistical similarity between troughs and regions adjoining the waves with overall higher skewness in the A ring, indicating more clumping and greater asymmetry in this region than in the inner B ring region.</p>

Strain-Tuned Nodal Ring in Two-Dimensional Zn3C6S6 Monolayers

The nodal ring material has recently attracted wide attention due to its singular properties and potential applications in spintronics. Here, two-dimensional Zn3C6S6 is calculated and discussed by using first-principle calculations. We found that two-dimensional Zn3C6S6 can generate a nodal ring at 10% compressive strain, and the existence of the ring is proved by a partial charge density map. And as the compressive strain increases, the nodal ring does not disappear. At the same time, the stability of the electron-orbit coupling to the nodal ring is applied. Our findings indicate that the two-dimensional Zn3C6S6 is promising in new electronic and spintronic applications.