A novel reconfigurable transmitarray (RTA) with two-dimensional (2D) wide beam steering capability is presented herein. Different from the traditional RTA with the discrete phase compensation (one-bit or multi-bits phase shift), a second order parallel bandpass filter model is used to realize the RTA elements with a 180° continuous phase compensation. A sandwich structure composed of the two patches with rectangular slots and the middle ground sheet with the cruciform slot is constructed for the phase shift characteristics of the frequency selective surface (FSS), and two varactor diodes are loaded across the rectangular slots on the two top and bottom patches. The simulated results show that the proposed elements could achieve continuous transmission phase compensation from 0° to 180° with a 3 dB insert loss within the operating band of 11.8–12.6 GHz. The RTA prototype with 16×16 elements and an aperture size of 6λ0×6λ0 at 12.2 GHz is fabricated and measured for experimental verification. The measured results show that its beam scanning range can reach ±50° in both horizontal and vertical planes with a peak gain of 22.76 dBi and a aperture efficiency of 24.65%. Furthermore, the sidelobe levels (SLLs) are lower than −17.8 dB, which is much better than most RTAs. The proposed RTA has potential applications in radar, microwave imaging and wireless communication systems with low-cost fabrication and a stable performance.
Radiation pneumonia and fibrosis are major clinical complications of radiotherapy for thoracic tumor patients, and may significantly reduce survival and quality of life. At present, no safe and effective radiation protection measures have been approved for clinical use. Phycocyanin, a protein responsible for photosynthesis from Spirulina, has been shown to have a variety of biological activities and to be beneficial for a variety of diseases, including pulmonary fibrosis. However, the preventive and protective effects of phycocyanin on radiation-induced pulmonary fibrosis have not been studied. X-ray single dose irradiation was used on the chest of mice to prepare a mouse model of pulmonary fibrosis, from which the effect of phycocyanin on pulmonary histopathologic change, pulmonary fibrosis, the microbiota in lung and gut, LPS, TNF-α, and IL-6 at different time after irradiation were evaluated. Phycocyanin alleviated the radiation-induced lung injury and reduced the level of inflammatory factors. Thorax irradiation led to the disorder in microbiota of the lung and gut. The variation trend of the diversity of the two tissues was opposite, but that of the microbiota composition was similar. The phycocyanin intervention regulated the composition of the lung and gut microbiota, transformed them into normal state, and reduced the level of LPS, which significantly reduced the abundance of inflammation-related bacteria, and increased the abundance of probiotics that produce short-chain fatty acids. Phycocyanin could regulate the radiation-induced disorder in lung and gut microbiota of mice, and reduce the radiation-induced lung inflammation and fibrosis.
Aiming at the deep reinforcement learning (DRL) robustness enhancement problem in the path planning scenario of disaster relief unmanned aerial vehicle (UAV), Based on the strategy of state attack and reward attack, this paper proposes an Adv-SR adversarial attack algorithm combining state disturbance and reward interference. This method realizes the targeted attack on the dominant state and advantage reward by constructing the dominant action detection model and electromagnetic disturbance module. In order to improve the robustness of the deep reinforcement learning algorithm, this paper proposes a state and reward dual defense framework (SR-DDF) that can deal with both S and R attacks at the same time. This defense method uses a dual prediction network to complete the recovery of disturbance sequences, which greatly improves the anti-interference ability of DRL. In this paper, the Open AI Gym simulation platform is used to build a disaster relief scenario model of UAV. The simulation results show that the attack and defense scheme proposed in this paper is superior to the traditional attack and defense algorithm, and has great advantages in attack effect and improving the robustness of DRL.
Spin–orbit torque (SOT) is an emerging candidate for electrically controlled magnetization switching in low-power and nonvolatile spintronic devices. However, SOT switching of perpendicular magnetization requires an auxiliary field or additional lateral symmetry breaking, which is difficult to achieve in practical applications. In particular, the mechanism of field-free switching through vertical symmetry breaking still lacks a quantitative description. In this work, a vertically asymmetric Co/Pt bilayer has been constructed through quantitative engineering of anisotropy gradient, while keeping the total magnetic thickness of the bilayer constant. Interestingly, the enhanced asymmetry with greater anisotropy gradient would induce higher SOT efficiencies and larger field-free switching ratios. Field-free switching can be attributed to the slight lateral asymmetry caused by the perpendicular anisotropy gradient. The SOT effective-field enhancement and field-free switching through quantitative engineering of the anisotropy gradient not only offer a deeper understanding of current-induced magnetization switching in perpendicularly asymmetric systems but also provide a potential avenue for practical applications of SOT devices at the wafer level.
Readers,the host computers and electronic tags form a large RFID circuit system,inevitably causing problems of signal integrity(SI)and electromagnetic compatibility(EMC)issues are increasingly prominent.On the issues of crosstalk producing mechanism and influencing factors in RFID systems,the Allgro PCB SI simulation software was used to simulate crosstalk and to analyse the suppressing and improving methods.By methods of widening the interconnects distance,reducing the dielectric layer thickness,and adding head joint minimum crosstalk was achieved,and these methods how to influence crosstalk were also analyzed.
In this paper, a scalable hardware accelerating system deployed on FPGA that can efficiently accelerate various types of convolution for semantic segmentation networks is designed. A hierarchical multiple line buffer structure is proposed to flexibly construct convolution dataflow and utilize FPGA on-chip resources. The accelerating system is validated on both ZYNQ series high performance SoC and XC7A100T board with a RISC-V core. The results show that the proposed system can be easily implemented and migrated to different FPGA platforms with high computation efficiency.
A novel anti-ESD TGFPTD SOI LDMOS was proposed firstly for improve ESD robustness of TGFPTD SOI LDMOS in this paper. The proposed device was obtained by introducing an additional n + implantation and rapid thermal annealing into the widen p-well region of conventional TGFPTD SOI LDMOS. 2D simulation of the proposed device upon a positive current pulse stimulus of HBM indicates that a hybrid conduction mechanism of Zener diodes, BJTs, SCR, resistors and capacitors exists during ESD period. Moreover, the gate voltage is clamped below 30% of the breakdown voltage of gate oxide and the induced gate charges are released in a very short time at about 1.0μs. Therefore, the proposed anti-ESD TGFPTD SOI LDMOS is featured of very high ESD robustness.
With the development of artificial intelligence, intelligent communication jamming decision making is an important research direction of cognitive electronic warfare. In this paper, we consider a complex intelligent jamming decision scenario in which both communication parties choose to adjust physical layer parameters to avoid jamming in a non-cooperative scenario and the jammer achieves accurate jamming by interacting with the environment. However, when the situation becomes complex and large in number, traditional reinforcement learning suffers from the problems of failure to converge and a high number of interactions, which are fatal and unrealistic in a real warfare environment. To solve this problem, we propose a deep reinforcement learning based and maximum-entropy-based soft actor-critic (SAC) algorithm. In the proposed algorithm, we add an improved Wolpertinger architecture to the original SAC algorithm in order to reduce the number of interactions and improve the accuracy of the algorithm. The results show that the proposed algorithm shows excellent performance in various scenarios of jamming and achieves accurate, fast, and continuous jamming for both sides of the communication.
The advancement of spin-orbit torque (SOT)-based spintronic devices hinges on the ability to optimize interfacial spin-orbit coupling phenomena. This work elucidates the modulation of key spintronic parameters by inserting an Ir layer at Pt/Co and PtCr/Pt(0.5)/Co interfaces. A comprehensive investigation into the thickness-dependent perpendicular magnetic anisotropy, Dzyaloshinskii-Moriya interaction, spin-orbit torque efficiency, and switching current density is undertaken. The results reveal that an ultrathin 0.1 nm Ir insertion layer can enhance the dampinglike SOT efficiency by over 26% in Pt/Co and 10% in PtCr/Co systems, attributed to increased interfacial impurity scattering. Strikingly, the magnetic anisotropy and Dzyaloshinskii-Moriya interaction exhibit a nonmonotonic relationship with Ir thickness, minimized at 0.4--0.5 nm, explained by interfacial roughness effects evidenced through first-principles calculations. The critical switching current density becomes widely tunable from $1.6--3.5\ifmmode\times\else\texttimes\fi{}{10}^{7}$ $({\text{A/cm}}^{2})$ in Pt/Ir/Co and $1.0--2.0\ifmmode\times\else\texttimes\fi{}{10}^{7}$ $({\text{A/cm}}^{2})$ in PtCr/Ir/Co, respectively, reduced by nearly 50% with a 0.4 nm Ir insertion. These findings provide significant physical insights into interfacial spin-orbit coupling mechanisms and interface engineering of spintronic devices using insertion layers. The capability to substantially increase SOT efficiency while reducing the switching current highlights the promise of an Ir insertion layer to unlock the full potential of SOT-MRAM technology.
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