Adaptive synchronization of uncertain chaotic systems via switching mechanism

This paper deals with the problem of synchronization for a class of uncertain chaotic systems. The uncertainties under consideration are assumed to be Lipschitz-like nonlinearity in tracking error, with unknown growth rate. A logic-based switching mechanism is presented for tracking a smooth orbit that can be a limit cycle or a chaotic orbit of another system. Based on the Lyapunov approach, the adaptation law is determined to tune the controller gain vector online according to the possible nonlinearities. To demonstrate the efficiency of the proposed scheme, the well-known chaotic system namely Chua＇s circuit is considered as an illustrative example.

Nonvolatile Resistive Switching and Physical Mechanism in LaCrO3 Thin Films

Polycrystalline LaCrO3（LCO） thin films are deposited on Pt/Ti/SiO2/Si substrates by pulsed laser deposition and used as the switching material to construct resistive random access memory devices. The unipolar resistive switching（RS） behavior in the Au/LCO/Pt devices exhibits a high resistance ratio of ~104 between the high resistance state（HRS） and low resistance state（LRS） and exhibits excellent endurance/retention characteristics.The conduction mechanism of the HRS in the high voltage range is dominated by the Schottky emission, while the Ohmic conduction dictates the LRS and the low voltage range of HRS. The RS behavior in the Au/LCO/Pt devices can be understood by the formation and rupture of conducting filaments consisting of oxygen vacancies,which is validated by the temperature dependence of resistance and x-ray photoelectron spectroscopy results.Further analysis shows that the reset current IR and reset power PR in the reset processes exhibit a scaling law with the resistance in LRS（R0）, which indicates that the Joule heating effect plays an essential role in the RS behavior of the Au/LCO/Pt devices.

Analysis and modeling of resistive switching mechanism oriented to fault tolerance of resistive memory based on memristor

With the progress of the semiconductor industry, resistive memories, especially the memristor, have drawn increasing attention. The resistive memory based on memrsitor has not been commercialized mainly because of data error. Currently, there are more studies focused on fault tolerance of resistive memory. This paper studies the resistive switching mechanism which may have time-varying characteristics. Resistive switching mechanism is analyzed and its respective circuit model is established based on the memristor Spice model.

Analysis and modeling of resistive switching mechanisms oriented to resistive random-access memory

With the progress of the semiconductor industry,the resistive random-access memory（RAM） has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms.We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models.Finally,simulations are presented.We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms,which are applied to explain their resistive switchings.

Review of resistive switching mechanisms for memristive neuromorphic devices

Memristive devices have attracted intensive attention in developing hardware neuromorphic computing systems with high energy efficiency due to their simple structure,low power consumption,and rich switching dynamics resembling biological synapses and neurons in the last decades.Fruitful demonstrations have been achieved in memristive synapses neurons and neural networks in the last few years.Versatile dynamics are involved in the data processing and storage in biological neurons and synapses,which ask for carefully tuning the switching dynamics of the memristive emulators.Note that switching dynamics of the memristive devices are closely related to switching mechanisms.Herein,from the perspective of switching dynamics modulations,the mainstream switching mechanisms including redox reaction with ion migration and electronic effect have been systemically reviewed.The approaches to tune the switching dynamics in the devices with different mechanisms have been described.Finally,some other mechanisms involved in neuromorphic computing are briefly introduced.

Resistive switching properties of SnO_(2)nanowires fabricated by chemical vapor deposition

Resistive switching(RS)devices have great application prospects in the emerging memory field and neuromorphic field,but their stability and unclear RS mechanism limit their relevant applications.In this work,we construct a hydrogenated Au/SnO_(2)nanowire(NW)/Au device with two back-to-back Schottky diodes and investigate the RS characteristics in air and vacuum.We find that the Ion/Io ff ratio increases from 20 to 10^(4)when the read voltage decreases from 3.1 V to^(-1)V under the condition of electric field.Moreover,the rectification ratio can reach as high as 10^4owing to oxygen ion migration modulated by the electric field.The nanodevice also shows non-volatile resistive memory characteristic.The RS mechanism is clarified based on the changes of the Schottky barrier width and height at the interface of Au/SnO_(2)NW/Au device.Our results provide a strategy for designing high-performance memristive devices based on SnO_(2)NWs.

A Novel Design of Mechanical Switch for the High Overload Environment

The internal structure of the inertial measurement unit(IMU)in active state is easily damaged in the high overload environment.So that the IMU is usually required to be powered within the disappearance of the high overload.In this paper,a mechanical switch is designed to enable the IMU based on the analysis of the impact of high overload on the power-supply circuit.In which,parameters of mechanical switch are determined through theoretical calculation and data analysis.The innovation of the proposed structure lies in that the mechanical switch is triggered through the high overload process and could provide a delay signal for the circuit.After all,the proposed switch is tested through mechanical simulation,impact test and practical test.The experimental results show that the designed mechanical switch can effectively and reliably provide the delay for the circuit and guarantee operation of the IMU under high overload.

Construction of a Normalized Full-Length cDNA Library of Sesame Developing Seed by DSN and SMART^(TM)

Sesame （Sesamue indicum L.） is one of the most important oilseed crops with high oil yield. Here, we described a simple and efficient method for constructing a normalized cDNA library from a high oil content cultivar of sesame Zhongzhi 14, during its oil accumulation stages. It combined switching mechanism at 5？end of RNA transcript （SMART） technique and duplex-specific nuclease （DSN） normalization methods. Double-stranded cDNAs were synthesized from mRNAs, processed by normalization and Sfi I restriction endonuclease, and finally the cDNAs were ligated to pDNR-LIB vector. The ligation mixture was transformed into Escherichia coli DH10B by electroporation. The capacity of the library was 1.0？06 clones in this library. Gel electrophoresis results indicated the fragments ranged from 700 to 2 000 bp, with the average size of 1 800 bp. Random picking clones showed that the recombination rate was 100%. The results showed that the cDNA library constructed successfully was a full-length library with high quality, and could be used to screen the genes related to development of oil synthesis.

Identification of LepA as PPIase reveals a common molecular mechanism of translational GTPases regulating L11 switch on the ribosome

LepA, the highly conserved translational GTPase (trGTPase), triggers one-codon back-movement of the elongating ribosome. Here we identify a new enzymatic activity

A potential-driven switch of activity promotion mode for the oxygen evolution reaction at Co_(3)O_(4)/NiO_(x)H_(y) interface

Co_(3)O_(4)spinel oxides have manifested promising activity toward the oxygen evolution reaction(OER)through effective modifications.For them to become top electrocatalysts,however,accurate accounts of the catalytic kinetics are essential to gain a deep understanding of the activity promotion mechanisms.Herein,we use a newly proposed kinetic model based on energetic span as the rate-determining term for the electrocatalytic reaction to throw light on the promotion mechanism of Co_(3)O_(4)interfaced with nickel hydroxides(NiO_(x)H_(y))for the OER.We find that depending on the electrode potential,the OER kinetics at the designed interface between Co_(3)O_(4)and NiO_(x)H_(y)are boosted in entirely different ways.As a result,the OER can occur at a lower onset potential as well as a low Tafel slope.This work emphasizes the benefit of using rational theoretical models for electrocatalyst design.

Triboelectric nanogenerator with mechanical switch and clamp circuit for low ripple output

For new renewable clean energy,triboelectric nanogenerators(TENGs)have shown great potential in response to the world energy crisis.Nevertheless,the alternating-current signal generated by a TENG needs to be converted into a direct-current signal to be effective in applications.Therefore,a power management circuit,comprising a clamp rectifier circuit and a mechanical switch,is proposed for the conversion and produces a signal having a low ripple coefficient.The power management circuit adopts a clamp circuit as the rectifier circuit to increase the rectified voltage,and reduces the loss resulted from the components by reducing the use of discrete components;the electronic switch in the buck regulator circuit is replaced with a mechanical switch to reduce cost and complexity.In a series of experiments,this power management circuit displayed a stable output voltage with a ripple voltage of 0.07 V,crest factor of 1.01,and ripple coefficient of 2.2%.The TENG provides a feasible method to generate stable electric energy and to supply power to low-consumption electronic devices.

Secure state estimation for cyber-physical systems with unknown input sliding mode observer

In recent years, cyber attacks have posed great challenges to the development of cyber-physical systems. It is of great significance to study secure state estimation methods to ensure the safe and stable operation of the system. This paper proposes a secure state estimation for multi-input and multi-output continuous-time linear cyber-physical systems with sparse actuator and sensor attacks. First, for sparse sensor attacks, we propose an adaptive switching mechanism to mitigate the impact of sparse sensor attacks by filtering out their attack modes. Second, an unknown input sliding mode observer is designed to not only observe the system states, sensor attack signals, and measurement noise present in the system but also counteract the effects of sparse actuator attacks through an unknown input matrix. Finally, for the design of an unknown input sliding mode state observer, the feasibility of the observing system is demonstrated by means of Lyapunov functions. Additionally, simulation experiments are conducted to show the effectiveness of this method.

Emerging of two-dimensional materials in novel memristor

The rapid development of big-data analytics(BDA),internet of things(IoT)and artificial intelligent Technology(AI)demand outstanding electronic devices and systems with faster processing speed,lower power consumption,and smarter computer architecture.Memristor,as a promising Non-Volatile Memory(NVM)device,can effectively mimic biological synapse,and has been widely studied in recent years.The appearance and development of two-dimensional materials(2D material)accelerate and boost the progress of memristor systems owing to a bunch of the particularity of 2D material compared to conventional transition metal oxides(TMOs),therefore,2D material-based memristors are called as new-generation intelligent memristors.In this review,the memristive(resistive switching)phenomena and the development of new-generation memristors are demonstrated involving graphene(GR),transition-metal dichalcogenides(TMDs)and hexagonal boron nitride(h-BN)based memristors.Moreover,the related progress of memristive mechanisms is remarked.

The conductive path in HfO_2:first principles study

The conductive path formed by the interstitial Ag or substitutional Ag in Hf02 was investigated by using the Vienna ab initio simulation package based on the DFT theory. The calculated results indicated that the ordering of interstitial Ag ions at special positions can form a conductive path, and it cannot form at other positions.The orientation dependence of this conductive path was then investigated. Various types of super cells are also built to study the rupture of the path, which corresponds to some possible ＂off＂ states.