Electric field control of spin-orbit torque in ferromagnets
has been intensively pursued in spintronics to achieve efficient memory and computing devices with ultralow energy consumption. Compared ...with ferromagnets, antiferromagnets
have huge potential in high-density information storage because of their ultrafast spin dynamics and vanishingly small stray field
. However, the manipulation of spin-orbit torque in antiferromagnets using electric fields remains elusive. Here we use ferroelastic strain from piezoelectric materials to switch the uniaxial magnetic anisotropy in antiferromagnetic Mn
Au films with an electric field of only a few kilovolts per centimetre at room temperature. Owing to the uniaxial magnetic anisotropy, we observe an asymmetric Néel spin-orbit torque
in the Mn
Au, which is used to demonstrate an antiferromagnetic ratchet. The asymmetry of the Néel spin-orbit torque and the corresponding antiferromagnetic ratchet can be reversed by the electric field. Our finding sheds light on antiferromagnet-based memories with ultrahigh density and high energy efficiency.
Flexible pressure sensors usually require functional materials with both mechanical compliance and appropriate electrical performance. Most sensors based on materials with limited compressibility can ...hardly balance between high sensitivity and broad pressure range. Here, we prepare a heterophasic ionogel with shape and stiffness memory for adaptive pressure sensors. By combining the microstructure alignment for stiffness changing and shape memory micro-inclusions for stiffness fixing, the heterophasic ionogels reveal tunable compressibility. This controllable pressure-deformation property of the ionogels results in the pressure sensors' programmable pressure-resistance behavior with tunable pressure ranges, varied detection limits, and good resolution at high pressure. Broad pressure ranges to 220 and 380 kPa, and tunable detection limit from 120 to 330 and 950 Pa are realized by the stiffness memory ionogel sensors. Adaptive detection is also brought out to monitor tiny pressure changes at low stiffness and distinguish different human motions at high stiffness. Using shape and stiffness memory materials in pressure sensors is a general design to achieve programmable performance for more complex application scenarios.
This paper studies the distributed rendezvous problem of multi-agent systems with novel event-triggered controllers. We have proposed a combinational measurement approach to event design and ...developed the basic event-triggered control algorithm. As a result, control of agents is only triggered at their own event time, which reduces the amount of communication and lowers the frequency of controller updates in practice. Furthermore, based on the convergence analysis of the basic algorithm, we have proposed a new iterative event-triggered algorithm where continuous measurement of the neighbor states is avoided. It is noted that the amount of communication among agents has been significantly reduced without obvious negative effects on the control performances. The effectiveness of the proposed strategies is illustrated by numerical examples in 3D spaces.
Voltage control of magnetism (VCM) is attracting increasing interest and exciting significant research activity driven by its profound physics and enormous potential for application. This review ...article aims to provide a comprehensive review of recent progress in VCM in different thin films. We first present a brief summary of the modulation of magnetism by electric fields and describe its discovery, development, classification, mechanism, and potential applications. In the second part, we focus on the classification of VCM from the viewpoint of materials, where both the magnetic medium and dielectric gating materials, and their influences on magnetic modulation efficiency are systematically described. In the third part, the nature of VCM is discussed in detail, including the conventional mechanisms of charge, strain, and exchange coupling at the interfaces of heterostructures, as well as the emergent models of orbital reconstruction and electrochemical effect. The fourth part mainly illustrates the typical performance characteristics of VCM, and discusses, in particular, its promising application for reducing power consumption and realizing high-density memory in several device configurations. The present review concludes with a discussion of the challenges and future prospects of VCM, which will inspire more in-depth research and advance the practical applications of this field.
Reactive oxygen species (ROS) play key roles in many physiological processes, such as cell signaling and host innate immunity. However, when they are overproduced, ROS may damage biomolecules in vivo ...and cause diseases such as cardiovascular or neurodegenerative diseases, cancer, and so forth. Oxidative stress is usually implicated in various inflammatory tissues, representing an important target for the development of various therapeutic strategies. Therefore, various probes for the in vitro detection of ROS or the in vivo diagnosis of the oxidative stress-relevant diseases have been developed. Oxidation-responsive polymers have also attracted great interest due to their potential applications in biomedical fields. In this feature article, we summarize six types of oxidation-responsive polymers based on different oxidation-responsive motifs. Poly(propylene sulfide)s, selenium-based polymers, aryl oxalate- and phenylboronic ester-containing polymers are discussed in detail, while poly(thioketal)s and proline-containing polymeric scaffolds are briefly introduced.
As unique building blocks for next‐generation optoelectronics, high‐quality 2D p–n junctions based on semiconducting transition metal dichalcogenides (TMDs) have attracted wide interest, which are ...urgent to be exploited. Herein, a novel and facile electron doping of WSe2 by cetyltrimethyl ammonium bromide (CTAB) is achieved for the first time to form a high‐quality intramolecular p–n junction with superior optoelectronic properties. Efficient manipulation of charge carrier type and density in TMDs via electron transfer between Br− in CTAB and TMDs is proposed theoretically by density functional theory (DFT) calculations. Compared with the intrinsic WSe2 photodetector, the switching light ratio (Ilight/Idark) of the p–n junction device can be enhanced by 103, and the temporal response is also dramatically improved. The device possesses a responsivity of 30 A W−1, with a specific detectivity of over 1011 Jones. In addition, the mechanism of charge transfer in CTAB‐doped 2D WSe2 and WS2 are investigated by designing high‐performance field effect transistors. Besides the scientific insight into the effective manipulation of 2D materials by chemical doping, this work presents a promising applicable approach toward next‐generation photoelectronic devices with high efficiency.
A novel and facile electron doping of 2D WSe2 by cetyltrimethyl ammonium bromide (CTAB) is achieved to form a high‐quality lateral p–n homojunction with superior optoelectronic properties. The high switching light ratio (≈105), superior photoresponsivity (30 A W−1), and specific detectivity (over 1011 Jones) of the device demonstrate its promising applications for highly sensitive photodetectors and low‐power photoelectronic devices.
The security strength of the traditional one-time-pad encryption system depends on the randomness of the secret key. However, It can hardly to generatea truerandom key by using the existing ...technologies and methods, and it is also difficult to issue and store the random keywhich is at least as long as the plaintext. Therefore, we pay more attention to the logical operation used in the encryption and decryption but not to how to generate the random key. The calculator, a three-dimensional DNA self-assembly pyramid structure, is designed to construct four common logical operations (AND, OR, NOT, XOR) by programming DNA interactions. And two novel one-time-pad cryptography schemes, a single-bit one-time-pad algorithm and improved double-bit one-time-pad algorithm, are proposed based on the calculator. The security fragments, used to construct the three-dimensional DNA self-assembly pyramid structure, are intercepted from a reference chain which is selected from the DNA database. All of the interception parameters are transmitted to recipient by hiding in DNA sequences. Only the authorized user can get all secret parameters to reconstruct the structure. The secret random key sequences for the two one-time-pad cryptography algorithms are generated by using logistic map. It only needs to share two parameters and thresholding function in sender and recipient without code books. The simulation results and security analysis show that the encryption algorithms are effective and can provide higher computational complexity as well as a reduced cracking probability except for the difficult of biological experiments.
Atherosclerosis (AS) is associated with high morbidity and mortality rates and currently has no effective treatment. This study was aimed at investigating the role of macrophage exosomes in the ...inflammation and apoptosis after HUVEC injury. We established the HUVEC injury model using 100 mg/L oxidized low-density lipoprotein (ox-LDL) or 50 ng/mL tumor necrosis factor-α (TNF-α). Cell proliferation was assessed using cell counting kit-8 (CCK8) assays, and the expression of miR-221, TNF-α, and IL-6, IL-10, and IL-1β was detected using quantitative real-time PCR (qRT-PCR). The apoptotic rate was analyzed by the TUNEL method, and the expressions of apoptosis-related proteins Bcl2, Caspase-3, and c-myc were detected by western blotting. Finally, miR-221-3p mimics and miR-221-3p inhibitors were constructed by liposome transfection to determine the mechanism of action of macrophage exosomes on HUVEC injury. The expression levels of IL-6, IL-1β, and TNF-α in the injury groups were higher than those in the normal group, but the expression of IL-10 in the injury groups was lower than that in the normal group. Meanwhile, the apoptotic rate of the HUVEC cell injury group was higher than that of the normal group. In contrast, the expression levels of IL-6, IL-1β, and TNF-α were lower in the M2 macrophage exosome (M2-Exo) group, but the expression of IL-10 was higher compared with the control group. The apoptosis rate was reduced in the M2-Exo group, and the expression of the proapoptotic gene Caspase-3 was reduced, while the expression of the antiapoptotic gene Bcl2 was increased. Liposome transfection of miR-221-3p mimics was able to enhance the effect of M2 macrophage exosomes. Thus, M2-Exo promotes HUVEC cell proliferation and inhibits HUVEC cell inflammation and apoptosis. miR-221-3p overexpression attenuates HUVEC cell injury-induced inflammatory response and apoptosis, while miR-221-3p gene inhibition enhances this inflammatory response and apoptosis.
In this paper, coverage control for mobile sensors with double-integrator dynamics and different maximum velocities on a circle is investigated. A generalized energy function is introduced in the ...proposed coverage control laws to guarantee order preservation of the sensors despite of the existence of unknown but bounded disturbances. The velocity constraint of each sensor is shown to be always satisfied throughout the coverage task. It is shown that the sensor network can be driven to a neighborhood of the optimal configuration minimizing the coverage cost function and an upper bound on the coverage cost function when time goes to infinity is also provided. Finally, a simulation example is given to illustrate the effectiveness of the proposed coverage control laws.
In order to solve the problems of low computational security in the encoding mapping and difficulty in practical operation of biological experiments in DNA-based one-time-pad cryptography, we ...proposed a one-time-pad cipher algorithm based on confusion mapping and DNA storage technology. In our constructed algorithm, the confusion mapping methods such as chaos map, encoding mapping, confusion encoding table and simulating biological operation process are used to increase the key space. Among them, the encoding mapping and the confusion encoding table provide the realization conditions for the transition of data and biological information. By selecting security parameters and confounding parameters, the algorithm realizes a more random dynamic encryption and decryption process than similar algorithms. In addition, the use of DNA storage technologies including DNA synthesis and high-throughput sequencing ensures a viable biological encryption process. Theoretical analysis and simulation experiments show that the algorithm provides both mathematical and biological security, which not only has the difficult advantage of cracking DNA biological experiments, but also provides relatively high computational security.
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