Stacking tunable interlayer magnetism in bilayer CrI3

Diverse interlayer tunability of physical properties of two-dimensional layers mostly lies in the covalent-like quasi-bonding that is significant in electronic structures but rather weak for energetics. Such characteristics result in various stacking orders that are energetically comparable but may significantly differ in terms of electronic structures, e.g. magnetism. Inspired by several recent experiments showing interlayer anti-ferromagnetically coupled CrI3 bilayers, we carried out first-principles calculations for CrI3 bilayers. We found that the anti-ferromagnetic coupling results from a new stacking order with the C2/m space group symmetry, rather than the graphene-like one with R3 as previously believed. Moreover, we demonstrated that the intra- and inter-layer couplings in CrI3 bilayer are governed by two different mechanisms, namely ferromagnetic super-exchange and direct-exchange interactions, which are largely decoupled because of their significant difference in strength at the strong- and weak-interaction limits. This allows the much weaker interlayer magnetic coupling to be more feasibly tuned by stacking orders solely. Given the fact that interlayer magnetic properties can be altered by changing crystal structure with different stacking orders, our work opens a new paradigm for tuning interlayer magnetic properties with the freedom of stacking order in two dimensional layered materials

Automation System Vibration Analysis Taking Environmental Factors into Consideration

This paper aims to investigate the vibration behavior of a propulsion system subjected to hull deformations ina two dimension circumstance. As known that large scale ships have great developments in recent years which could cause much severer conditions among the interaction between the propulsion system and ship hull. Excited forces from thesea waves could make the ship hull deformed which further cause drastic vibrations of the shaft system. As a result, the malfunctions of shaft propulsion system are potential existed as the vibrations of the shaft always exceed its maximum allowable values.This paper establishes a simplified model of the large ship propulsion-hull system to analyze the vibration behavior of the ship propulsion system subjected to the ship hull deformations. The hull deformations were obtained as the excited forces under different sea conditions. Then base on the simplified 2D model, the effects of propeller, supports stiffness, the location of hull excitations, the amplitude of excitations are discussed.

Multiplexed Sensor Array for Accurate Time-of-Wetness (TOW) Measurement

In this work, we use electrochemical impedance spectroscopy (EIS) to observe the response of a single, photo-lithographically created, interdigital transducer (IDT) sensor, dimensions 6mm X 6 mm, with capacitive elements 70μm X 500 nm. The IDT was exposed to different wetting conditions, droplets of DI water, 0.1 M NaCl, and 0.6 M NaCl, in volumes of 0.1, 0.3, 1, and 5 μL. Deliquescence of solid NaCl salt particles in a dynamic-humidity (%RH Increasing, 33% to 85%) atmosphere is examined. Equivalent circuit fitting of impedance spectra suggests linear trends for the capacitive equivalent circuit element parameters and a decaying logarithmic trend for the resistive element, with respect to electrolyte concentration vs. area of wetting. The sensor development process includes a 1 by 5 proof-of-concept linear array, and the eventual goal of a 5 by 5 matrix array. The array sensor aims to (1) determine the overall fraction of wet surface area, and (2) distinguish between electrolytes of varying conductivity, in a 2-dimensional gradient across a surface

FPGA-Based In-Vivo Calcium Image Decoding for Closed-Loop Feedback Applications

The miniaturized calcium imaging is an emerging neural recording technique that can monitor neural activity at large scale at a specific brain region of a rat or mice. It has been widely used in the study of brain functions in experimental neuroscientific research. Most calcium-image analysis pipelines operate offline, which incurs long processing latency thus are hard to be used for closed-loop feedback stimulation targeting certain neural circuits. In this paper, we propose our FPGA-based design that enables real-time calcium image processing and position decoding for closed-loop feedback applications. Our design can perform real-time calcium image motion correction, enhancement, and fast trace extraction based on predefined cell contours and tiles. With that, we evaluated a variety of machine learning methods to decode positions from the extracted traces. Our proposed design and implementation can achieve position decoding with less than 1 ms latency under 300 MHz on FPGA for a variety of mainstream 1-photon miniscope sensors. We benchmarked the position decoding accuracy on open-sourced datasets collected from six different rats, and we show that by taking advantage of the ordinal encoding in the decoding task, we can consistently improve decoding accuracy without any overhead on hardware implementation and runtime across the subjects.Comment: 11 pages, 15 figure