Application of artificial synapse based on all-inorganic perovskite memristor in neuromorphic computing

Artificial synapse inspired by the biological brain has great potential in the field of neuromorphic computing and artificial intelligence.The memristor is an ideal artificial synaptic device with fast operation and good tolerance.Here,we have prepared a memristor device with Au/CsPbBr_(3)/ITO structure.The memristor device exhibits resistance switching behavior,the high and low resistance states no obvious decline after 400 switching times.The memristor device is stimulated by voltage pulses to simulate biological synaptic plasticity,such as long-term potentiation,long-term depression,pair-pulse facilitation,short-term depression,and short-term potentiation.The transformation from short-term memory to long-term memory is achieved by changing the stimulation frequency.In addition,a convolutional neural network was constructed to train/recognize MNIST handwritten data sets;a distinguished recognition accuracy of~96.7%on the digital image was obtained in 100 epochs,which is more accurate than other memristor-based neural networks.These results show that the memristor device based on CsPbBr3 has immense potential in the neuromorphic computing system.

Research of Natural Gesture Recognition and Interactive Technology Compatible with YCb Crand HSV Color Space

In view of the current gesture recognition algorithm based on skin color segmentation is not flexible and has weak resistance to the environment, this paper puts forward a new method of skin color modeling to improve the adaptability of gesture segmentation when it face to different states. The modeling built by double color space instead of only one is compatible both in YCbCr and HSV color space to training the Gaussian model which can update the threshold value for binarization. Finally, this paper designed a natural gesture recognition and interactive systems based on the double color space model. It has shown that the system has a good interactive experience in different environments.

Dielectric and Pyroelectric Properties of （Pb0.50Sr0.50）TiO3 Ceramics

Lead strontium titanate （Pb0.50Sr0.50）TiO3 （PST） ceramics are prepared by the traditional ceramic processing. The dielectric constants and dielectric loss have been investigated in a temperature range from 25℃ to 300℃. The maximum dielectric constants for unpoled and poled samples are 9924 and 9683, respectively. The temperatures of phase transition for unpoled and poled samples are observed at 153℃ and 157℃, respectively. The phasetransition temperatures for unpoled and poled samples are not equal, which results from the polarization state of the domains. The remnant polarization and the coercive electric field are 18 uC/cm^2 and 6 kV/cm, respectively, from polarization-electric field （P - E） hysteresis loop. The temperature dependence of pyroelectric coefficients of the PST ceramics is measured by a dynamic technique. The dielectric constant and loss Lan δ of the poled PST ceramics are 813 and 0.010, respectively. The pyroelectric coefficients and figure of merit are 294 uC/cm^2 K and 13.6 × 10^-6 pa^-0.5, respectively, at room temperature 25℃and frequency lOOHz.

XPS study of BZT thin film deposited on Pt/Ti/SiO_2/Si substrate by pulsed laser deposition

Ferroelectric materials were widely applied for actuators and sensors. Barium zirconate titanate Ba(Zr0.25Ti0.75)O3 thin film was grown on Pt/Ti/SiO2/Si(100) substrates by pulsed laser deposition. Structure and surface morphology of the thin film were studied by X-ray diffractometry(XRD) and scan electronic microscopy(SEM). The composition and chemical state near the film surface were obtained by X-ray photoelectron spectroscopy(XPS). On the sample surface,O 1s spectra can be assigned to those from the lattice and surface adsorbed oxygen ions,while C1s only result from surface contamination. The result shows that only one chemical state is found for each spectrum of Ba 3d,Zr 3d and Ti 2p photoelectron in the BZT thin film.

Magnesium incorporation activates perovskite cobaltites toward efficient and stable electrocatalytic oxygen evolution

Cobalt-rich perovskite oxides play a paramount role in catalyzing oxygen evolution reaction(OER)on account of their acceptable intrinsic activity but are still challenging due to the high costs and undesired stability.In response to the defects,herein,the Mg-incorporated perovskite cobaltite SrCo_(0.6)Fe_(0.3M)g_(0.1)O_(3-δ)(SCFM-0.1)is proposed as a novel earth-abundant and durable OER electrocatalyst.A well-consolidated cubic-symmetry structure and more active oxygen intermediates are enabled upon Mg substitution.Hence,the optimized SCFM-0.1 perovskite oxide achieves prominent OER electrocatalytic performance,that is,a low overpotential of only 320 mV at 10 mA cm^(-2),a small Tafel slope of 65 mV dec^(-1),as well as an outstanding durability within 20 h,substantially outperforming that of the pristine SrCo_(0.7)Fe_(0.3)O_(3-δ)and benchmark Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)and IrO_(2) catalysts.The strong pHdependent behavior associated with lattice oxygen activation mechanism for SCFM-0.1 catalyst is also confirmed.This work paves a unique avenue to develop cost-effective and robust perovskite cobaltites for efficient OER electrocatalysis.

Achieving exceptional activity and durability toward oxygen reduction based on a cobalt-free perovskite for solid oxide fuel cells

In response to the shortcomings of cobalt-rich cathodes, iron-based perovskite oxides appear as promising alternatives for solid oxide fuel cells (SOFCs). However, their inferior electrochemical performance at reduced temperatures (<700 ℃) becomes a major bottleneck for future progress. Here, a novel cobalt-free perovskite Ba_(0.75)Sr_(0.25)Fe_(0.875)Ga_(0.125)O_(3−δ) (BSFG) is developed as an efficient oxygen reduction electrode for SOFCs, featuring cubic-symmetry structure, large oxygen vacancy concentration and fast oxygen transport. Benefiting from these merits, cells incorporated with BSFG achieve exceptionally high electrochemical performance, as evidenced by a low polarization area-specific resistance of 0.074 Ω cm^(2) and a high peak power density of 1145 mW cm^(−2) at 600 ℃. Meanwhile, a robust short-term performance stability of BSFG cathode can be ascribed to the stable crystalline structure and favorable thermal expansion behavior. First-principles computations are also conducted to understanding the superior activity and durability toward oxygen reduction reaction. These pave the way for rationally developing highly active and robust cobalt-free perovskite-type cathode materials for reduced-temperature SOFCs.

High recoverable energy storage density of Na_(0.5)Bi_(0.5)TiO_(3) lead-free ceramics modified by Bi(Mg_(0.5)Hf_(0.5))O_(3)

Enhancing the availability and reliability of dielectric ceramic energy storage devices is of great importance.In this work,(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xBi(Mg_(0.5)Hf_(0.5))O_(3)(NBT-xBMH)lead-free ceramics were created utilizing a solid-state reaction technique.All NBT-xBMH ceramics have a single perovskite structure.With increasing BMH doping,the grain size shrinks drastically,which greatly enhances the breakdown electric field(310 kV/cm at x=0.25).Additionally,the relaxation behaviors of NBT-xBMH ceramics with high BMH content are more remarkable.Among all designed components,the NBT-0.25BMH ceramic exhibits the best energy storage performance with a high Wrec of 4.63 J/cm^(3) and anηof 75.1%at 310 kV/cm.The NBT-0.25BMH ceramic has exceptional resistance to fluctuations in both frequency(5-500 Hz)and temperature(30-100°C).Charge-discharge test shows that the NBT-0.25BMH ceramic has a quick discharge rate(t0.9<110 ns).With these properties,the NBT-0.25BMH ceramic may have applications in microdevices as well as in ultra-high power electronic systems.

Emerging memristors and applications in reservoir computing

Recently, with the emergence of ChatGPT, the field of artificial intelligence has garnered widespread attention from various sectors of society. Reservoir Computing (RC) is a neuromorphic computing algorithm used to analyze time-series data. Unlike traditional artificial neural networks that require the weight values of all nodes in the trained network, RC only needs to train the readout layer. This makes the training process faster and more efficient, and it has been used in various applications, including speech recognition, image classification, and control systems. Its flexibility and efficiency make it a popular choice for processing large amounts of complex data. A recent research trend is to develop physical RC, which utilizes the nonlinear dynamic and short-term memory properties of physical systems (photonic modules, spintronic devices, memristors, etc.) to construct a fixed random neural network structure for processing input data to reduce computing time and energy. In this paper, we introduced the recent development of memristors and demonstrated the remarkable data processing capability of RC systems based on memristors. Not only do they possess excellent data processing ability comparable to digital RC systems, but they also have lower energy consumption and greater robustness. Finally, we discussed the development prospects and challenges faced by memristors-based RC systems.

Artificial synaptic simulating pain-perceptual nociceptor and brain-inspired computing based on Au/Bi_(3.2)La_(0.8)Ti_(3)O_(12)/ITO memristor

Recently, memristors have garnered widespread attention as neuromorphic devices that can simulate synaptic behavior, holding promise for future commercial applications in neuromorphic computing. In this paper, we present a memristor with an Au/Bi_(3.2)La_(0.8)Ti_(3)O_(12) (BLTO)/ITO structure, demonstrating a switching ratio of nearly 103 over a duration of 104 s. It successfully simulates a range of synaptic behaviors, including long-term potentiation and depression, paired-pulse facilitation, spike-timing-dependent plasticity, spike-rate-dependent plasticity etc. Interestingly, we also employ it to simulate pain threshold, sensitization, and desensitization behaviors of pain-perceptual nociceptor (PPN). Lastly, by introducing memristor differential pairs (1T1R-1T1R), we train a neural network, effectively simplifying the learning process, reducing training time, and achieving a handwriting digit recognition accuracy of up to 97.19 %. Overall, the proposed device holds immense potential in the field of neuromorphic computing, offering possibilities for the next generation of high-performance neuromorphic computing chips.

Toxicity assessment and histopathological analysis of nano-ZnO against marine fish(Mugilogobius chulae) embryos

The toxicity of nano-materials has received increasing attention in recent years. Nevertheless, relatively few studies have focused on their oceanic distributions and toxicities. In this study, we assessed nano-ZnO toxicity in marine organisms using the yellowstriped goby （Mugilogobius chulae）. The relative differences in nano-ZnO dissolution and dispersal in seawater and fresh water were also investigated. The effects of nano-ZnO on embryonic development, deformity, hatching, mortality, and histopathology were analyzed. In addition, the effects of the Zn2＋ concentration on M. chulae hatching and mortality were compared. The results showed that nano-ZnO had higher solubility in seawater than in fresh water. Nano-ZnO significantly inhibited hatching. By the fifth day of exposure, the LC50 of nano-ZnO was 45.40 mg/L, and the mortality rate spiked. Hatching inhibition and lethality were dose-dependent over a range of 1-25 mg/L nano-ZnO. Zn2＋ inhibited hatching and increased lethality, but its effects were weaker than those of nano-ZnO at the same concentrations. Nano-ZnO also induced spinal bending, oedema, hypoplasia, and other deformities in M. chulae embryos and larvae. Histopathology revealed vacuolar degeneration, hepatocyte and enterocyte enlargement, and morphological abnormalities of the vertebrae. Therefore, nano-ZnO caused malformations in M. chulae by affecting embryonic growth and development. We conclude that nano-ZnO toxicity in seawater was significantly positively correlated with the associated Zn2＋ concentration and sedimentary behaviour. The toxicity of nano-ZnO was cumulative and showed a critical point, beyond which embryonic and developmental toxicity in marine fish was observed.

Continuous-flow synthesis of doped all-inorganic perovskite nanocrystals enabled by a microfluidic reactor for light-emitting diode application

All-inorganic perovskite nanocrystals(AIPNCs)possess the advantages of narrow emission spectrum,high quantum efficiency of luminescence and tunable luminescence position,which show a broad application prospect in the fields of optoelectronic materials and devices.Ion doping can tune their pristine crystal structures and luminescent properties or endow the AIPNCs with additional functionalities.Herein,a microfluidic reactor is designed to produce the Ce3+-doped AIPNCs based on the continuous-flow reaction.The mechanism of the flow synthesis of Ce3+-doped AIPNCs is the efficient physical mixing of the precursor ions in the confined micro-channel,the reaction nucleation of crystal seeds in the poor solvent and the crystal growth of the doped AIPNCs along the flow direction.The synthesis process can be on-line monitored by an optical fiber absorption spectrometer and an optical fiber fluorescence spectrometer.The doping concentration of Ce3+can be facilely controlled by changing the flow parameters in the microfluidic reactor,and the highest value reaches 1%.The Ce3+doping can improve the photoluminescence efficiency and the stability of the AIPNCs.The Ce3+-doped CsPbBr3AIPNCs can be used to manufacture green light-emitting diodes(LEDs)with a high color purity of93.3%and white LEDs with correlated color temperature(CCT)of 10,436 K,CIE color coordinates of(0.261,0.317)and color-rendering index(CRI)of 72.1.The continuous and controllable synthesis of AIPNCs by microfluidic reactor opens up new avenues for the application of the high-performance optoelectronic materials and devices.

SYNTHESIS OF NATURAL RUBBER-g-MALEIC ANHYDRIDE AND ITS USE AS A COMPATIBILIZER IN NATURAL RUBBER/SHORT NYLON FIBER COMPOSITES

Natural rubber grafted maleic anhydride （NR-g-MAH） was synthesized by mixing maleic anhydride （MAH） and natural rubber （NR） in solid state in a torque rheometer using dicurnyl peroxide （DCP） as initiator. Then the self-prepared NR-g-MAH was used as a compatibilizer in the natural rubber/short nylon fiber composites. Both the fimctionalization of NR with MAH and the reaction between the modified rubber and the nylon fiber were confirmed by Fourier transform infrared spectroscopy （FTIR）. Composites with different nylon short fiber loadings （0, 5, 10, 15 and 20 phr） were compounded on a two-roll mill, and the effects of the NR-g-MAH on the tensile and thermal properties, fiber-rubber interaction, as well as the morphology of the natural rubber/short nylon fiber composites were investigated. At equal fiber loading, the NR-g-MAH compatibilized NR/short nylon fiber composites showed improved tensile properties, especially the tensile modulus at 100% strain which was about 1.5 times that of the corresponding un-compatibilized ones. The equilibrium swelling tests proved that the incorporation of NR-g-MAH increased the interaction between the nylon fibers and the NR matrix. The crosslink density measured with NMR techniques showed that the NR-g-MAH compatiblized composites had lower total crosslink density. The glass transition temperatures of the compatibilized composites were about 1 K higher than that of the corresponding un-compabilized ones. Morphology analysis of the NR/short nylon fiber composites confirmed NR-g-MAH improved interfacial bonding between the NR matrix and the nylon fibers. All these results signified that the NR-g-MAH could act as a good compatilizer of NR/short nylon fiber composites and had a potential for wide use considering its easy to be prepared and compounded with the composites.

Ni(OH)_2 nanoflakes supported on 3D hierarchically nanoporous gold/Ni foam as superior electrodes for supercapacitors

The increasing demand for portable electronic devices and hybrid electric vehicles stimulates the develop- ment of supercapacitors as an advanced energy storage system. Here, we demonstrate a binder-free nickel hydroxide@nano- porous gold/Ni foam （Ni（OH）2@NPG/Ni foam） electrode for high-performance supercapacitors, which is prepared by a facile three-step fabrication route including electrodeposition of Au-Sn alloy on Ni foam, chemical dealloying of Sn and electrodepostion of Ni（OH）2 on NPG/Ni foam. Such Ni（OH）2@NPG/Ni foam electrode is composed of a thin layer of conformable Ni（OH）2 nanoflakes supported on three-di- mensional （3D） hierarchically porous NPG/Ni foam substrate. The resulting Ni（OH）2@NPG/Ni foam electrode can offer highways for both electron transfer and ion transport and lead to an excellent electrochemical performance with an ultrahigh specific capacitance of 3,380 F g-1 at a current density of 2 A g-1. Even when the current density was increased to 50 A g-1, it still retained a high capacitance of 1,927 F g-1. The promising performance of the Ni（OH）2@NPG/Ni foam elec- trode is mainly ascribed to the 3D hierarchical porosity and the highly conductive network on the NPG/Ni foam composite current collector, as well as the conformal electrodeposition of Ni（OH）2 active material on the NPG/Ni foam, which induces the formation of interconnected porosity both on the top surface and on the inner surface of the electrode. This in- spiring electrochemical performance would make the as-de- signed electrode material become one of the most promising candidates for future electrochemical energy storage systems.

Enhanced energy-storage density and temperature stability of Pb_(0.89)La_(0.06)Sr_(0.05)(Zr_(0.95)Ti_(0.05))O_(3) anti-ferroelectric thin film capacitor

As the fundamental energy storage components in electronic systems,dielectric capacitors with high power densities were demanded.In this work,the anti-ferroelectric Pb_(0.89)La_(0.06)Sr_(0.05)(Zr_(0.95)Ti_(0.05))O_(3)(PLSZT)ceramics and thin film capacitor were successfully fabricated by a solid-state reaction route and pulsed laser deposition method,respectively.The ferroelectric,dielectric,energy-storage properties,and temperature stability of anti-ferroelectric PLSZT capacitor were investigated in detail.By compared with the PLSZT ceramic(energy storage density is 1.29 J/cm^(3) with an efficiency of 78.7%under 75 kV/cm),the anti-ferroelectric PLSZT thin film capacitors exhibited the enhanced energy storage density of 52.6 J/cm^(3) with efficiency of 67.7%under an electric field as high as 2068.9 kV/cm,and the enhanced energy-storage temperature stabilities from room temperature(RT)to more than 200℃ were demonstrated,and the oxygen defects mechanism and size effect were discussed.Moreover,the fast charging(~0.05 μs)and discharging(~0.15 μs)time were certified for the anti-ferroelectric PLSZT film capacitor.These findings broaden the horizon for PLSZT anti-ferroelectrics in high energy storage properties and show promising for manufacturing pulse power capacitor.

Pb-DOPING EFFECTS ON THE DIELECTRIC AND PYROELECTRIC PROPERTIES OF(Sr,Pb)TiO_(3)SYSTEM

Lead strontium titanate(Sr_(1-x)Pbx)TiO_(3)(0.20≤x≤0.45,step=0.05)ceramics were prepared by conventional mixed oxide method.The X-ray diffraction patterns indicate that the prepared samples have perovskite-type structure.With the increase of Pb content,there is a tendency from the cubic to tetragonal structure.The scanning electron microscopy micrographs reveal that the addition of Pb can affect microstructure.The dependent temperature dielectric permittivity and dielectric loss were investigated in the frequency range from 100 Hz to 1MHz.The maximum peak of the dielectric permittivity versus temperature curve was broadened and a frequency dispersion of the dielectric permittivity was observed for the(Sr_(0.8)Pb_(0.2))TiO_(3)ceramics.The results obtained at the frequency of 10 kHz reveal the Curie temperature linearly increased with the lead content.Thefitted curves of temperature versus inverse dielectric permittivity at 10 kHz for(Sr_(1-x)Pbx)TiO_(3)ceramics are consistent with Curie-Weiss law.The Pyroelectric properties were also investigated.The high pyroelectric coe±cients andfigure of merits indicate that the SPT ceramics are potential materials for pyroelectric sensors.

Excellent energy storage properties realized in novel BaTiO_(3)-based lead-free ceramics by regulating relaxation behavior

BaTiO_(3)(BT)has attracted extensive attention among advanced lead-free ferroelectric materials due to its unique dielectric and ferroelectric properties.However,the enormous remanent polarization and coercive field severely impede the improvement of its energy storage capabilities.Here,the BaTiO_(3)e-Bi(Zn_(0.5)Hf_(0.5))O_(3)(BT-BZH)ceramics with high breakdown field strength and remarkable relaxation characteristics can be obtained by introducing the composite component BZH in BT to regulate the phase structure and grain size of the ceramics.The findings demonstrate that the improvement of energy storage performance is related to the increase of relaxation behavior.A large energy storage density(Wrec~3.62 J/cm^(3))along with superior energy storage efficiency(h~88.5%)is achieved in 0.88BT-0.12BZH relaxor ceramics only at 240 kV/cm.In addition,the sample suggests superior thermal stability and frequency stability within 25e115℃and 1e500 Hz,respectively.Furthermore,the outstanding chargedischarge properties with an ultrafast discharge time(100 ns),large discharged energy density(1.2 J/cm^(3)),impressive current density(519.4 A/cm^(2))and power density(31.1 MW/cm^(3))under the electric field of 120 kV/cm are achieved in studied ceramics.The excellent energy storage performance of BT-BZH ceramics provides a promising platform for the application of lead-free energy-storage materials.

Superior Energy and Power Density Realized in Pb(Hf_(1-x)Ti_(x))O_(3) System at Low Electric Field

The development of antiferroelectric materials with large energy density and fast discharge speed makes dielectric capacitors possess great prospects for applications in pulsed power technology.Here,the PbHfO_(3)-based ceramics with compositions of Pb(Hf_(1-x)Ti_(x))O_(3)(PHT,0.01≤x≤0.05)were synthesized,and their antiferroelectricity and phase transition behavior were studied.According to the tests of x-ray diffraction,dielectric spectrum,and polarization-electric field hysteresis loops,PHT ceramics gradually transition from an orthorhombic symmetric antiferroelectric phase to a hexagonal symmetric ferroelectric phase at room temperature as Ti^(4+)concentration increases.The forward phase switching field of antiferroelectric to ferroelectric phase transition can be markedly regulated by the introduction of Ti^(4+),and the optimal energy storage performance was obtained in Pb(Hf_(0.98)Ti_(0.02))O_(3) ceramics with a large recoverable energy storage density of Wrec~4.15 J/cm^(3) and efficiency ofη~65.3%only at a low electric field of 190 kV/cm.Furthermore,the outstanding charge-discharge properties with an ultrafast discharge time(71 ns),remarkable discharged energy density(2.84 J/cm^(3)),impressive current density(1,190 A/cm^(2)),and ultrahigh power density(101 MW/cm^(3))at a low electric field of 170 kV/cm were obtained in studied ceramics.The excellent energy storage performance of PHT ceramics provides a promising platform for the application of dielectric capacitors.

面向高稳定的光纤和生物相容性细胞平台的柔性荧光金属有机框架

荧光金属有机框架(FMOF)是一种很有前途的光电和生物应用材料,然而,一些主要缺点限制了它们在这些领域的广泛应用.首先,FMOF晶体难以用来构建柔性的自支撑平台.此外,这些材料对外部刺激表现出较低的光学稳定性,并且用于合成它们的金属离子通常有毒.基于此,我们开发了一种同轴微流控纺丝方法,实现了一步大规模连续制备核-壳FMOF微纤维.获得的自支撑FMOF基超细纤维具有85.6 MPa的高抗拉强度,是MOF复合材料中的最高强度值.此外,还证明了用该微流控方法生成的交联水凝胶壳可以有效地提高位于微纤维核心的FMOF晶体的光学稳定性,对抗可能会损坏FMOF的化学物质(如金属离子、酸、碱)以及热.最重要的是,由于水凝胶外壳的生物相容性和微纤维核心的固有荧光,基于FMOF的超细纤维具有较高的细胞活力(约96.6%)和多种细胞外荧光成像能力.因此,本文报道的基于柔性FMOF微纤维为设计光学和生物医学应用的新概念和材料组件提供了一个先进的平台.

Acid-base Vapor Sensing Enabled by ESIPT-attributed Cd(II) Coordination Polymer with Switchable Luminescence

Fluorescence materials based on excited state intramolecular proton transfer(ESIPT)have attracted great attentiori due to the unique four-level energy states.Herein,we report the assembly of a Cd-LF coordination polymer from purposely designed LF(H2hpi2cf)ligand,which can present switchable luminescence behavior by gain or loss protons originated in uncoordinated ESIPT sites and serve as acid-base vapor sensors.Fabricated into in-situ grown film or transparent ink by simple methods,Cd-LF presents facile and portable amine sensor for food spoilage detection and fluorescent anti-counterfeiting ink applications.