Dual-band metamaterial absorber with stable absorption performance based on fractal structure

In this paper, two kinds of dual-band metamaterial absorbers (MMAs) with stable absorption performance based on fractal structures are proposed. As the key feature, with the increase in fractal order, the fractal MMAs can reduce the weight while keeping the absorption performance. The multi-band absorption property is analyzed by multiple L-C resonances generated by the fractal structure. By virtue of good impedance matching characteristics and the synergy of the circuit and electromagnetic resonance, effective and stable microwave absorption is readily achieved. Finally, two prototypes are fabricated for demonstration, and the measurement result is consistent well with the simulation one. As expected, the proposed fractal MMAs have the advantage of low-cost, light-weight, and dual-effective absorption bands, and have great potential in the application of multi-band radar stealth.

Low-voltage driven graphene-loaded metal wire grating device in total internal reflection geometry for broadband THz modulation

Terahertz modulators with capability of both intensity and phase are essential for THz imaging and communication systems. The low-voltage driven THz modulation technique is crucial for integrating the modulators with electronics components. There is still a lack of broadband devices able to achieve both amplitude and phase modulation with low voltage, due to the underlying physics behind existing approaches. Here, we demonstrate a graphene-loaded metal wire grating THz modulator in the total internal reflection geometry to achieve intensity modulation of 80% and phase modulation of 70 degree within 3 volts gate voltage. Quite different from using the strategy of metamaterials based on the electromagnetic resonance effects, our design has performed a broadband modulation for over 1 THz bandwidth.

Electromagnetic resonance of nonlinear vacuum in one-dimensional cavity

Nonlinear corrections on electromagnetic fields in vacuum have been expected. In this study, we have theoretically considered nonlinear Maxwell’s equations in a one-dimensional cavity for a classical light and external static electromagnetic fields. A general solution for the electromagnetic corrective components including that of a longitudinal standing wave was derived after a linearization. The main purpose is to give a detailed feature of the previously reported resonant behavior [Shibata, Euro. Phys. J. D 74:215 (2020)], such as the effect of external static fields and the polarization fluctuation. These results favor the development of new and effective method for experiment. Graphic abstract

Neurological conditions caused by microgravity

Background: Since Space Tourism is closer to reality, a review of the most prevalent neurological pathologies in microgravity is needed. Objective: Review major neurological afflictions in astronauts. Methods: Research into bibliographic reviews at PubMed, using the descriptors “astronauts” and “neurological disorders” Results: Several neurological alterations, such as ataxy, intracranial hypertension (ICH), neuromuscular disorders, ocular disturbances and changes in cognitive functions were assigned to a microgravity environment. Astronauts returning from space presented ICH; being the main pathophysiology hypothesis referred to a change in the liquor dynamics as a result of venous drainage obstruction and hematoencephalic barrier. Also, gravity doesn’t act on the neurovestibular system during space flights. This phenomenon can lead to Space Motion Sickness, situation in which astronauts report balance, coordination and sight disturbances, as well as movement illusions. A subset of this syndrome, called Space Movement Disorder, may occur; which includes symptoms, such as flushing, anorexia, nausea, vomiting, dizziness and malaise. Based on electromagnetic resonance, the occurrence of problems with movement time, balance, spatial working memory and motor coordination after the return of the space crew suggests alterations in cerebellum’s function and structure, which is responsible for the coordination and the fine motor control. Conclusion: Most studies presented disruptions of the neurofunctional homeostasis, for instance, changes in functional connectivity while in rest and alterations of the white and grey matter in sensor motor, somatosensory and cognitive regions of the brain.

Design and Application of Intelligent House Robot

As a family-oriented hexapod bionic intelligent house robot, it takes life safety monitoring, intelligent house control, air quality detection, family security, automatic inspection and obstacle avoidance as its main functions. Combined with core technologies including Face and Radio Frequency Identification, Electromagnetic Resonance and Induction, LAM, Intelligent Navigation and Cloud Robot, the robot is established a unique triangular gait in the form of hexapod, which can maintain the function and action stability in various environments, thus become a family housekeeper with multiful functions and practical intelligence.

Application of Systems for Complex Integrative Automatic Assembly of Electronic Components Super Systems and Subsystems with Pre-Stamping of Incoming Parts and Elements

An essential part of any production process is to actively monitor the parameters of these processes in real time. The most promising method of active real time monitoring is non contact monitoring or monitoring in the mode of electromagnetic resonance spectroscopy. Since these methods are fundamentally new and are only being implemented in technological processes, it makes sense to consider them in more detail.