Achieving ultrahigh energy-storage capability in PbZrO3-based antiferroelectric capacitors based on optimization of property parameters

Energy-storage properties is a critical role to decide whether or not the dielectric capacitors can be applied in high power pulse devices, but single improvement in electric filed parameters or...

Liquid-film Motor: Physical Mechanism

A liquid film that is under the action of two electric forces, an external electric field parallel to the film and a lateral voltage difference applied to both edges of the film, exhibits a universal rotational flow. In this article, we revisit this phenomena by considering an idealized so-called liquid-film motor and provide a theoretical description of the underlying physical mechanism that is responsible for the rotation. In this theory, the external electric filed induces a non-uniform distribution of free charges on the film then the internal field, resulted mainly from the voltage difference, will exert forces on these charges and subsequently induce a rotational flow in the ambient fluid. We show, how the fields contribute in developing a universal flow pattern.

Fine multi-coil electronic control of transcranial magnetic stimulation: effects of stimulus orientation and intensity

Despite the evident benefit of transcranial magnetic stimulation (TMS) to probe human brain function and treat neurological diseases, current technology allows only a slow, mechanical adjustment of the electric filed orientation. Automated and fast control of the TMS orientation is critical to enable synchronizing the stimulation with the ongoing brain activity. We overcome these limitations with a two-coil electronically controlled TMS transducer to define precisely the pulse orientation (~1-degree steps) without mechanical movement. We validated the technology by determining the dependency of motor evoked responses on the stimulus orientation and intensity with high angular resolution. The motor response was found to follow a logistic function of the stimulus orientation, which helps to disentangle the TMS neuronal effects. The electronic control of the TMS electric field is a decisive step towards automated brain stimulation protocols with enhanced accuracy of stimulus targeting and timing for better diagnostics and improved clinical efficacy.

Comprehensive Analysis of Electric Field Characteristics for Multi-Winding Medium Frequency Transformer

The multi-winding medium frequency transformer (MMFT) has attracted widespread attention, since its application in power electronic transformers can simplify the system structure and reduce the volume and weight. However, the special working conditions of MMFT due to high voltage and high power density increase the difficulty of insulation design for MMFT. For this issue, this paper presents a comprehensive analysis of electric filed characteristics for MMFT. First, the electric field model of MMFT is established using the 2-D finite element method. Based on it, the influences of connection mode, core structure, and hollow winding on the electric field characteristics of MMFT are studied, including the overall electric field distribution, maximum electric field intensity, and the electric field intensity along a fixed path. The results show that there are differences in the maximum electric field intensity for different connection modes and different core structures, which provides references for MMFT insulation design. The proposed modeling method and analysis results in this paper are important for insulation improvement of MMFT.

Analysis of ARROW Waveguide based Microcantilever for Sensing Application

Analysis of microcantilever beam and ARROW microcantilever waveguides are presented in this work. The microcantilever is simulated by using the silicon nitride material. Electric voltage applied creates the deformation in the cantilever beam. The deformation leads to displacement of the beam. The displacement is due to bending of the cantilever tip. The integration of MEMS cantilever and ARROW waveguide results in the ARROW microcantilever waveguide. The ARROW microcantilever waveguide quality factor, electric filed intensity and sensitivity analysis are the three important parameters presented. The quality factor is obtained by varying the air gap distance between cantilever waveguide and output waveguide. Through this simulation using FDTD sensitivity up to 73.78 nm/RIU has been achieved for the microcantilever arrow waveguide.

Design of Driving Waveform Based on a Damping Oscillation for Optimizing Red Saturation in Three-Color Electrophoretic Displays

At present, three-color electrophoretic displays (EPDs) have problems of dim brightness and insufficient color saturation. In this paper, a driving waveform based on a damping oscillation was proposed to optimize the red saturation in three-color EPDs. The optimized driving waveform was composed of an erasing stage, a particles activation stage, a red electrophoretic particles purification stage, and a red display stage. The driving duration was set to 360 ms, 880 ms, 400 ms, and 2400 ms, respectively. The erasing stage was used to erase the current pixel state and refresh to a black state. The particles’ activation stage was set as two cycles, and then refreshed to the black state. The red electrophoretic particles’ purification stage was a damping oscillation driving waveform. The red and black electrophoretic particles were separated by changing the magnitude and polarity of applied electric filed, so that the red electrophoretic particles were purified. The red display stage was a low positive voltage, and red electrophoretic particles were driven to the common electrode to display a red state. The experimental results showed that the maximum red saturation could reach 0.583, which was increased by 27.57% compared with the traditional driving waveform.

Dynamics of Ion Channels via Non-Hermitian Quantum Mechanics

We study dynamics and thermodynamics of ion transport in narrow, water-filled channels, considered as effective 1D Coulomb systems. The long range nature of the inter-ion interactions comes about due to the dielectric constants mismatch between the water and the surrounding medium, confining the electric filed to stay mostly within the water-filled channel. Statistical mechanics of such Coulomb systems is dominated by entropic effects which may be accurately accounted for by mapping onto an effective quantum mechanics. In presence of multivalent ions the corresponding quantum mechanics appears to be non-Hermitian. In this review we discuss a framework for semiclassical calculations for the effective non-Hermitian Hamiltonians. Non-Hermiticity elevates WKB action integrals from the real line to closed cycles on a complex Riemann surfaces where direct calculations are not attainable. We circumvent this issue by applying tools from algebraic topology, such as the Picard-Fuchs equation. We discuss how its solutions relate to the thermodynamics and correlation functions of multivalent solutions within narrow, water-filled channels.