Self-repairing functionality and corrosion resistance of in-situ Mg-Al LDH film on Al-alloyed AZ31 surface

A novel Mg-Al LDH film was in-situ prepared hydrothermally in an alkaline aqueous solution on an Al-alloyed AZ31 substrate.The structural,chemical and functional characteristics of the film were explored by means of scanning electron microscope(SEM),X-ray diffraction(XRD),energy dispersive spectrometer(EDS),polarization curve,AC impedance and salt immersion tests,respectively.The anti-corrosion results indicated that the Mg-Al LDH film on the Al-alloyed AZ31 surface could effectively protect the AZ31 from corrosion attack even after 90 days of immersion in 3.5 wt.%NaCl solution.The protection performance is surprisingly better than most of the reported coatings on Mg alloys.More interestingly,when the Mg-Al LDH film was scratched,the exposed Al-alloyed surface might gradually release metal ions and re-generate dense LDH nano-sheets in the corrosive environment to inhibit the further corrosion there,exhibiting a self-repairing behavior.The combination of the benign long-term protection and desirable self-repairing performance in this new process of surface-alloying and LDH-formation may significantly extend the practical application of magnesium alloys.

Recent progress in self-repairing coatings for corrosion protection on magnesium alloys and perspective of porous solids as novel carrier and barrier

Featuring low density and high specific strength, magnesium(Mg) alloys have attracted wide interests in the fields of portable devices and automotive industry. However, the active chemical and electrochemical properties make them susceptible to corrosion in humid, seawater, soil,and chemical medium. Various strategies have revealed certain merits of protecting Mg alloys. Therein, engineering self-repairing coatings is considered as an effective strategy, because they can enable the timely repair for damaged areas, which brings about long-term protection for Mg alloys. In this review, self-repairing coatings on Mg alloys are summarized from two aspects, namely shape restoring coatings and function restoring coatings. Shape restoring coatings benefit for swelling, shrinking, or reassociating reversible chemical bonds to return to the original state and morphology when coatings broken;function self-repairing coatings depend on the release of inhibitors to generate new passive layers on the damaged areas. With the advancement of coating research and to fulfill the demanding requirements of applications, it is an inevitable trend to develop coatings that can integrate multiple functions(such as stimulus response, self-repairing, corrosion warning,and so on). As a novel carrier and barrier, porous solids, especially covalent organic frameworks(COFs), have been respected as the future development of self-repairing coatings on Mg alloys, due to their unique, diverse structures and adjustable functions.

On the Survivability of Self-repairing Control System for a Hybrid Underwater Vehicle

A hybrid remotely operated underwater vehicle( HROV) capable of working to the full ocean depth has been developed. In order for the vehicle to achieve a certain survivability level,a self-repairing control system( SRCS) has been designed. It consists of two basic technologies,fault diagnosis and isolation( FDI) and reconfigurable control. For FDI,a model-based hierarchical fault diagnosis system is designed for the HROV. Then,control strategies which reconfigure the control system at intervals according to information from the FDI system are presented. Combining the two technologies,it can obtain the fundamental frame of SRCS for the HROV. Considering the hazardous underwater environment at the limiting depth and the hybrid operating modes,an assessment of the HROV's survivability is vitally needed before it enters operational service. This paper presents a new definition of survivability for underwater vehicles and develops a simple survivability model for the SRCS. As a result of survivability assessment for the SRCS,we are able to figure out the survivability of SRCS and make further optimization about it. The methodology developed herein is also applicable to other types of underwater vehicles.

A self-repairing polymer-inorganic composite coating to enable high-performance Zn anodes for zinc-ion batteries

There are some critical issues hindering the practical applications of aqueous zinc-ion batteries(zIBs),although they possess high safety and low cost as one of promising energy storge devices,such as the Zn dendrite growth and the by-product of Zn_(4)SO_(4)(OH)_(6)-xH_(2)O(ZHS)resulted from some side reactions in a mild electrolyte.Herein,a compact and self-repairing solid electrolyte interface(SEl)film,as labeled the PVDF-Zn(TFSI)_(2)-ZHS coating[The PVDF and Zn(TFSI)_(2)are polyvinylidene fluoride and zinc bis(trifluoromethanesulfonyl)imide,respectively],which turns the in-situ generated ZHS into a beneficial ingredient onto the pre-coated PVDF-based composite coating layer containing Zn(TFSI)_(2),was designed and fabricated by a simple doctor blade method.It is shown that the SEl layer can effectively isolate Zn from the electrolyte and homogenize the Zn^(2+)flux,and thus effectively suppress side reactions and dendrites growth.Benefiting from the hybrid SEl layer,a symmetric cell exhibits a high cycling stability over 750h at 2.0 mA/cm^(2)and 2.0 mAh/cm^(2),and meanwhile,a full-cell,coupled with K^(+) pre-intercalationα-MnO_(2)(KMO)cathode,displays excellent rate performance,stable coulombic efficiency and an acceptable cycle life.This work provides a feasible approach for simple and scalable modification of Zn anodes to achieve high performance.

Emerging Trends in Damage Tolerance Assessment:A Review of Smart Materials and Self-Repairable Structures

The discipline of damage tolerance assessment has experienced significant advancements due to the emergence of smart materials and self-repairable structures.This review offers a comprehensive look into both traditional and innovative methodologies employed in damage tolerance assessment.After a detailed exploration of damage tolerance concepts and their historical progression,the review juxtaposes the proven techniques of damage assessment with the cutting-edge innovations brought about by smart materials and self-repairable structures.The subsequent sections delve into the synergistic integration of smart materials with self-repairable structures,marking a pivotal stride in damage tolerance by establishing an autonomous system for immediate damage identification and self-repair.This holistic approach broadens the applicability of these technologies across diverse sectors yet brings forth unique challenges demanding further innovation and research.Additionally,the review examines future prospects that combine advanced manufacturing processes with data-centric methodologies,amplifying the capabilities of these‘intelligent’structures.The review culminates by highlighting the transformative potential of this union between smart materials and self-repairable structures,promoting a sustainable and efficient engineering paradigm.

Research on Tribological Characteristics and Worn Surface Self-Repairing Performance of Nano Attapulgite Powders Used in Lubricant Oil as Addictive

As a kind of natural nanometer materials,the attapulgite has been widely used in industry,agriculture,environment,food substance,medicament and many other fields.Few researches about attapulgite used in lubricant oil as additive were made,and those were only at a preliminary stage of exploration.The tribological characteristics of attapulgite powders with the different contents added to CD 15W/40 lubricant oil were researched through"plane-on-plane"configuration friction and wear tester,and the self-repairing performance of 45#steel worn surface was examined via ring-on-block configuration test.XRD,SEM,EDS,TEM were employed to analyze the surface morphologies and elementary composition of the samples'worn surface.Furthermore,wear self-repairing mechanism of attapulgite additive to lubricant oil was explored.The results showed that:the optimal content of attapulgite powders in oil CD 15W/40 was 0.5 wt%,and the stable friction coefficient can be reduced to 0.02,then the friction reduction performance can be enhanced by 82.5%;Smooth worn surface were formed of the chemical reaction film containing elements O,Si,Fe;Friction reduction and self-repairing mechanism had a relation with the crystal structure of attapulgite.

A shape memory scaffold for body temperature self-repairing wearable perovskite solar cells with efficiency exceeding 21%

Grain boundary cracks in flexible perovskite films can be repaired by filling with self-repairing polymers during the preparation and wearable operation.However,the self-repairing polymers are commonly active through external heating or humidification treatments,which cannot match with the human body's temperature tolerance of wearable devices.Herein,a body temperature-responsive shape memory polyurethane(SMPU)is demonstrated to achieve the real-time mechanical self-repairing of grain boundary cracks(~37°C).Furthermore,the strong intermolecular interaction between SMPU and the uncoordinated Pb2+and I−,can reduce the trap density in perovskite films.The blade-coated device achieves a power conversion efficiency(PCE)of 21.33%,which is among the best reported flexible perovskite solar cells(PSCs;0.10 cm2).Importantly,the device with SMPU can recover more than 80%of the PCE after 6000 cycles(bending radius:8 mm).Finally,the flexible PSCs are used for wearable solar power supply of a smartphone,which show great potential for self-repairing wearable electronics.

BOARD-LEVEL BUILT-IN SELF-REPAIR METHOD OF RAM

This paper describes the method of built-in self-repairing of RAM on board, designs hardware circuit, and logic for the RAM's faults self-repairing system based on FPGA. The key technology is that it utilizes FPGA to test RAM according to some algorithm to find out failure memory units and replace the faulty units with FPGA. Then it can build a memory that has no fault concern to external controller, and realizes the logic binding between external controller and RAM. Micro Controller Unit (MCU) can operate external RAM correctly even if RAM has some fault address units. Conventional MCS-51 is used to simulate the operation of MCU operating external memory. Simulation shows FPGA can complete the faulty address units' mapping and MCU can normally read and write external RAM. This design realizes the RAM's built-in self-repairing on board.

Plants as concept generators for biomimetic light-weight structures with variable stiffness and self-repair mechanisms

Plants possess many structural and functional properties that have a high potential to serve as concept generators for the production of biomimetic technical materials and structures. We present data on two features of plants (variable stiffness due to pressure changes in cellular structures and rapid self-repair functions) that may be used as models for biomimetic projects.

Elimination-Evolution Self-repair Method for Bio-inspired Electronic System

The existing self-repair methods,evolvable hardware and embryonic electronics( embryonics) are analyzed. Based on the advantages and disadvantages of the existing self-repair methods,a novel self-repair method named elimination-evolution self-repair method is proposed. The system can be repaired through elimination in real time and evolved to optimize the allocation of system resources with this method. The proposed self-repair method not only ensures the speed of the system's self-repair,but also makes full use of system resources to improve the system's self-repair capacity and provides a new self-repair approach for bio-inspired electronic system. In the end,the advantages of the proposed eliminationevolution self-repair method are verified through a simulation experiment.

Influence of Working Memory Capacity on the Frequency of Self-Repairs

This article explored the influence of working memory capacity on the frequency of self-repairs.The narrative task and listening span task were used.Twenty post-graduate students participated in this study.Overall,the results of this study illustrated that the working memory is a factor of self-repairs.Speakers who have higher working memory capacity produce lesser self-repairs.This finding provides teachers with a new insight into second language teaching;that is,teachers can improve the amount of lexical knowledge when teaching students who have lower working memory in order to help them produce more accurate language during the process of L2 speech production.

A multifunctional osteogenic system of ultrasonically spray deposited bone-active coatings on plasma-activated magnesium

Biomimetic bone-active coatings composed of inorganic nano-hydroxyapatite(i.e.,nHA)and organic silk fibroin(i.e.,SF)are layer-by-layer deposited on Mg-Zn-Ca alloy by a controllable ultrasonic spray method.Meanwhile,plasma activation is developed as a promising strategy to pretreat magnesium surfaces,which facilitates the direct adhesion of coatings with enhanced bonding interfaces.In this work,we engineer the nHA/SF composite coatings with excellent mechanical properties and adhesion force.The optimized parameters of ultrasonic spray bring significant influence on the surface morphologies of coatings.Assisted by hybrid plasma of oxygen and nitrogen(i.e.,O_(2)/N_(2) plasma),the activated Mg-Zn-Ca surfaces are uniformly covered by a robust and compact nHA/SF composite coating,establishing a multifunctional system with superior corrosion resistance and biological performance.Interestingly,secondary oxygen plasma treatment of nHA/SF coatings(A-nHA/SF)promotes the hydrophilicity,leading to a rapid self-repair effect from surface damage.The improvement of anti-corrosion and self-repair provides a dependable platform for better cell adhesion,proliferation,spreading and differentiation.These favorable factors contribute to the preferable in vivo biocompatibility and the promotion of newly formed bones for the A-nHA/SF-coated Mg implants.This study lays important foundations for coating strategy on biomedical magnesium alloy as multifunctional osteogenic system in bioactive implantable applications.

Pressure induced stability: from pneumatic structures to Tensairity~

Structural stabilization by a pressurized fluid is very common in nature, however hardly found in technology. Car tires, hot air balloons, airships and airhouses are among the few technical exceptions, which are stabilized by a compressed medium, typically air. Restricted by simple geometries and a very limited load bearing capacity these pneumatic structures could succeed only in very specialized applications. Nevertheless, prospective concepts ag has systematically investigated pneumatic structures during the last few years. As a major result, it was demonstrated that almost any shape can be made with pneumatic structures and that astonishing structures such as the pneumatic airplane Stingray can be realized even with low air pressure. On top of that, Airlight Ltd. in close collaboration with prospective concepts ag has recently developed the fundamental new structural concept Tensairity. The synergetic combination of an inflated structure with conventional structural elements such as cables and struts yields pneumatic light-weight structures with the load bearing capacity of steel girders. Thus, complex forms and high strength open up many new opportunities for pressure induced stability in technology. An overview of these recent developments is presented and the close relationship of pneumatic structures with biology is outlined.

CELLULAR SUBSTANCE EXUDATION AND SEED VIGOUR

In this paper.seeds of pinus koraiensis which has a characteristic of deep dormancywere selected as an expriment material,and the relation of cellular substance exudation to seed vig-our is discussed based on the dormant state,the different measuring parts and the imbibed state ofseeds before testing,as well as on the respiration of embryo and endosperm.The major measured re-sults are as follows:(1)After soaking for 24h,the dry embryo conductivity of seedlot L is greaterthat than of seedlot H:(2)The substance exudation of dry embryo of seedlot H is less than that ofseedlot L;(3)After seeds imbibed,the substance exudation of dormant embryo of seedlot H is morethan that of seedlot L;(4)After germination hastening treatment,the substance exudation of H em-bryos is greater than that of L embryos;(5)After artificially accclcrated ageing treatment,the em-bryo conductivity of imbibed seeds has a positive correlation with seed vigour.

A long lifetime,low error rate RRAM design with self-repair module

Resistive random access memory(RRAM) is one of the promising candidates for future universal memory.However,it suffers from serious error rate and endurance problems.Therefore,exploring a technical solution is greatly demanded to enhance endurance and reduce error rate.In this paper,we propose a reliable RRAM architecture that includes two reliability modules:error correction code(ECC) and serf-repair modules.The ECC module is used to detect errors and decrease error rate.The serf-repair module,which is proposed for the first time for RRAM,can get the information of error bits and repair wear-out cells by a repair voltage.Simulation results show that the proposed architecture can achieve lowest error rate and longest lifetime compared to previous reliable designs.

Optimal design of RTCs in digital circuit fault self-repair based on global signal optimization

Since digital circuits have been widely and thoroughly applied in various fields, electronic systems are increasingly more complicated and require greater reliability. Faults may occur in electronic systems in complicated environments. If immediate field repairs are not made on the faults, electronic systems will not run normally, and this will lead to serious losses. The traditional method for improving system reliability based on redundant fault-tolerant technique has been unable to meet the requirements. Therefore, on the basis of(evolvable hardware)-based and(reparation balance technology)-based electronic circuit fault self-repair strategy proposed in our preliminary work, the optimal design of rectification circuits(RTCs) in electronic circuit fault self-repair based on global signal optimization is deeply researched in this paper. First of all, the basic theory of RTC optimal design based on global signal optimization is proposed. Secondly, relevant considerations and suitable ranges are analyzed. Then, the basic flow of RTC optimal design is researched. Eventually, a typical circuit is selected for simulation verification, and detailed simulated analysis is made on five circumstances that occur during RTC evolution. The simulation results prove that compared with the conventional design method based RTC, the global signal optimization design method based RTC is lower in hardware cost, faster in circuit evolution, higher in convergent precision, and higher in circuit evolution success rate. Therefore, the global signal optimization based RTC optimal design method applied in the electronic circuit fault self-repair technology is proven to be feasible, effective, and advantageous.

The biomimetic design provides efficient self-healing of ultrahightough and damage-warning bio-based elastomer for protective clothing of metals

Facing the ubiquitous corrosion threat,the great significance of developing high-performance protective materials with the dual function of self-healing defects and self-warning damage is extremely challenging.Herein,inspired by the biological skin and pearls,we proposed that the biological polyurethanes(PU)embedded with multiple dynamic bonds(reversible hydrogen bonds and aromatic disulfide bonds)were combined with polydopamine(PDA)/1,10-phenanthroline(Phen)/graphene oxide(GO)(PPG)nanosheets(PDA encapsulated GO with Phen)to obtain a versatile nacre structure polymer with the interface hydrogen bond between PPG and PU matrix.The biomimetic polymer not only guarantees ultrahigh toughness(116.1 MJ·m^(-3))and abnormal elongation(2320%)but shows satisfactory repair performance(81%under 25℃ for 3 h),and the coating can accelerate damage recovery(87%)under near-infrared light(NIR)irradiation for 1 h due to the photothermal properties of PPG.The warning of damages in the coating can be enabled through the Phen chelation Fe^(2+)ions that bring in the corrosion reaction to produce a conspicuous red color,thereby achieving the active warning function of the bionic coating on defects for the first time.In addition,the electrochemical tests exhibit that the repair performance and protection effect of the biomimetic coating in 3.5 wt.%NaCl solution are also trustworthy,and this highly reliable bio-based bionic coating brings a revolutionary program to inaugurate multifunctional and high-performance intelligent materials under harsh environments.

Embryonic array configuration optimization method based on reliability and hardware consumption

Embryonic Array(EA) with different configuration methods will directly affect its reliability and hardware consumption. At present, EA configuration design is lack of quantitative analysis method. In order to reasonably optimize EA configuration design, an EA configuration optimization design method is proposed, which is based on the constraints of EA hardware consumption and reliability. Through the analysis of EA working process and composition, quantitative analysis of EA reliability and hardware consumption are completed. Based on the constraints of EA hardware consumption and reliability, the mathematical model of EA configuration optimization design is established, which transfers EA configuration optimization design into an integer nonlinear programming model problem. According to the difference of the fitness value of individual waiting for mutation in population, adaptive mutation operator and crossover operator are selected, and a novel Modified Adaptive Differential Evolution(MADE) algorithm is proposed,which is used to solve EA configuration optimization design problem. Simulation experiments and analysis indicate that the MADE is able to effectively improve the speed, accuracy and stability of algorithm. Moreover, the proposed EA configuration optimization design method can select the most reasonable EA configuration design, and play an important guiding role in EA optimization design.

Repair the faulty TSVs with the improved FNS-CAC codec

Through-silicon via(TSV)is a key enabling technology for the emerging 3-dimension(3 D)integrated circuits(ICs).However,the crosstalk between the neighboring TSVs is one of the important sources of the soft faults.To suppress the crosstalk,the Fibonacci-numeral-system-based crosstalk avoidance code(FNS-CAC)is an effective scheme.Meanwhile,the self-repair schemes are often used to deal with the hard faults,but the repaired results may change the mapping between signals to TSVs,thus may reduce the crosstalk suppression ability of FNS-CAC.A TSV self-repair technique with an improved FNS-CAC codec is proposed in this work.The codec is designed based on the improved Fibonacci numeral system(FNS)adders,which are adaptive to the health states of TSVs.The proposed self-repair technique is able to suppress the crosstalk and repair the faulty TSVs simultaneously.The simulation and analysis results show that the proposed scheme keeps the crosstalk suppression ability of the original FNS-CAC,and it has higher reparability than the local self-repair schemes,such as the signal-switching-based and the signal-shifting-based counterparts.