ZnMn_2O_4 thin films were deposited by a sol-gel technique onto a p+-Si substrate, and a RRAM device with the Ag/ZnMn_2O_4/p^+-Si structure was fabricated. The microstructure of ZnMn_2O_4 films and the resistive switc...ZnMn_2O_4 thin films were deposited by a sol-gel technique onto a p+-Si substrate, and a RRAM device with the Ag/ZnMn_2O_4/p^+-Si structure was fabricated. The microstructure of ZnMn_2O_4 films and the resistive switching behavior of Ag/ZnMn_2O_4/p^+-Si device were investigated. ZnMn_2O_4 thin films had a spinel structure after annealing at 650 °C for 1 h. The Ag/ZnMn_2O_4/p^+-Si device showed unipolar and/or bipolar resistive switching behavior, exhibiting different ION/IOFF ratio and switching endurance properties. In bipolar resistive switching, high-resistance-state(HRS) conduction was dominated by the space-charge-limited conduction mechanism, whereas the filament conduction mechanism dictated the low resistance state(LRS). For unipolar resistive switching, HRS and LRS were controlled by the filament conduction mechanism. For bipolar resistive switching, the conduction process can be explained by the space-charge region of the p-n junction.展开更多
As a critical command center in organisms,the brain can execute multiple intelligent interactions through neural networks,including memory,learning and cognition.Recently,memristive-based neuromorphic devices have bee...As a critical command center in organisms,the brain can execute multiple intelligent interactions through neural networks,including memory,learning and cognition.Recently,memristive-based neuromorphic devices have been widely developed as promising technologies to build artificial synapses and neurons for neural networks.However,multiple information interactions in artificial intelligence devices potentially pose threats to information security.Herein,a transient form of heterogeneous memristor with a stacked structure of Ag/MgO/SiN_(x)/W is proposed,in which both the reconfigurable resistive switching behavior and volatile threshold switching characteristics could be realized by adjusting the thickness of the SiN_(x)layer.The underlying resistive switching mechanism of the device was elucidated in terms of filamentary and interfacial effects.Representative neural functions,including short-term plasticity(STP),the transformation from STP to long-term plasticity,and integrate-and-fire neuron functions,have been successfully emulated in memristive devices.Moreover,the dissolution kinetics associated with underlying transient behaviors were explored,and the water-assisted transfer printing technique was exploited to build transient neuromorphic device arrays on the water-dissolvable poly(vinyl alcohol)substrate,which were able to formless disappear in deionized water after 10-s dissolution at room temperature.This transient form of memristive-based neuromorphic device provides an important step toward information security reinforcement for artificial neural network applications.展开更多
The memristor, as the fourth basic circuit element, has drawn worldwide attention since its physical implementation was released by HP Labs in 2008. However, at the nano-scale, there are many difficulties for memristo...The memristor, as the fourth basic circuit element, has drawn worldwide attention since its physical implementation was released by HP Labs in 2008. However, at the nano-scale, there are many difficulties for memristor physical realization. So a better understanding and analysis of a good model will help us to study the characteristics of a memristor. In this paper, we analyze a possible mechanism for the switching behavior of a memristor with a Pt/TiO2/Pt structure, and explain the changes of electronic barrier at the interface of Pt/TiO2. Then, a quantitative analysis about each parameter in the exponential model of memristor is conducted based on the calculation results. The analysis results are validated by simulation results. The efforts made in this paper will provide researchers with theoretical guidance on choosing appropriate values for(α, β, χ, γ) in this exponential model.展开更多
ZnMn_2O_4 films for resistance random access memory（RRAM） were fabricated with different device structures by magnetron sputtering. The effects of electrode on I-V characteristics, resistance switching behavior, end...ZnMn_2O_4 films for resistance random access memory（RRAM） were fabricated with different device structures by magnetron sputtering. The effects of electrode on I-V characteristics, resistance switching behavior, endurance and retention characteristics of ZnMn_2O_4 films were investigated. The ZnMn_2O_4 films, using p-Si and Pt as bottom electrode, exhibit bipolar resistive switching（BRS） behavior dominated by the space-charge-limited conduction（SCLC） mechanism in the high resistance state（HRS） and the filament conduction mechanism in the low resistance state（LRS）, but the ZnMn_2O_4 films using n-Si as bottom electrodes exhibit both bipolar and unipolar resistive switching behaviors controlled by the Poole-Frenkel（P-F） conduction mechanism in both HRS and LRS. Ag/ZnMn_2O_4/p-Si device possesses the best endurance and retention characteristics, in which the number of stable repetition switching cycle is over 1000 and the retention time is longer than 106 seconds. However, the highest RHRS/R_（LRS） ratio of 104 and the lowest V_（ON） and V_（OFF） of 3.0 V have been observed in Ag/ZnMn_2O_4/Pt device. Though the Ag/ZnMn_2O_4/n-Si device also possesses the highest RHRS/R_（LRS） ratio of 104, but the highest values of V_（ON）,V_（OFF）, RHRS and R_（LRS）, as well as the poor endurance and retention characteristics.展开更多
Sugar and protein are the major macronutrients＇ sources, and their balanced intake is important for animal＇s health. It has been observed that animals are able to change food preference in an imbalanced nutritional ...Sugar and protein are the major macronutrients＇ sources, and their balanced intake is important for animal＇s health. It has been observed that animals are able to change food preference in an imbalanced nutritional condition to selectively consume nutrients that are deficient in the body （Dethier, 1976）. Early studies in both Drosophila and mouse have demonstrated that animals exhibit food rejection to imbalanced diets lacking essential amino acids （Hao et al., 2005; Bjordal et al., 2014）. Furthermore, the food preference change upon protein depri- vation has been characterized using a two choice assay in Drosophila （Ribeiro and Dickson, 2010; Vargas et al., 2010）. Different from protein food, sugar is the main energy source, and sugar deficiency severely affects animal survival （Lee et al., 2008）. However, whether animals adopt a strategy of fast food preference switch upon sugar deprivation had not been investigated, and the neural mechanisms underlying this behavior regulation remain poorly understood.展开更多
Three novel dithienylethenes modified by bifluoroboron β-diketonate fragments have been successfully developed. Upon blue light irradiation, they reached photostationary state within 2-5 s, as well as 100% conversion...Three novel dithienylethenes modified by bifluoroboron β-diketonate fragments have been successfully developed. Upon blue light irradiation, they reached photostationary state within 2-5 s, as well as 100% conversion ratio and photocyclization quantum yield of > 0.70. Such fascinating photochromism were endowed by collaborative role of electron-withdrawing effect of BF_(2)bdk group to reduce HOMO-LUMO electronic gap for the open isomer, together with intramolecular hydrogen bonds and CH-π interactions favoring antiparallel conformation fixation. Moreover, they displayed specific discrimination and photoswitchable bacterial imaging for S. aureus.展开更多
Central banks worldwide have started researching and developing central bank digital currencies(CBDCs).In the digital economy context,concerns regarding the integrity,competition,and privacy of CBDC systems have also ...Central banks worldwide have started researching and developing central bank digital currencies(CBDCs).In the digital economy context,concerns regarding the integrity,competition,and privacy of CBDC systems have also gradually emerged.Against this backdrop,this study aims to evaluate users’willingness to use China’s digital currency electronic payment(DCEP)system,a digital payment and processing network,and its influencing factors by comprehensively considering and comparing the characteristics of cash and third-party payment services.Combining the push-pull-mooring frame-work(PPM)and task-technology fit(TTF)theory,we discuss the scenarios and mecha-nisms that may inspire users’DCEP adoption intention through an empirical study.The results reveal that privacy concerns regarding the original payment methods and technology-task fitting level of DCEP positively impact users’willingness to adopt DCEP.The technical characteristics of DCEP,users’payment requirements,and government support positively affect users’adoption intention by influencing the task-technology fitting degree of DCEP.Switching cost significantly and negatively impacts adop-tion intention,whereas relative advantage exhibits no significant effect.This research contributes to a better understanding of the factors that influence switching intentions and the actual use of DCEP,and provides policy guidance on promoting the efficiency and effectiveness of DCEP.展开更多
In gene regulatory networks, gene regulation loops often occur with multiple positive feedback, multiple negative feedback and coupled positive and negative feedback forms. In above gene regulation loops, auto-activat...In gene regulatory networks, gene regulation loops often occur with multiple positive feedback, multiple negative feedback and coupled positive and negative feedback forms. In above gene regulation loops, auto-activation loops are ubiquitous regulatory motifs. This paper aims to investigate a two-component dual-positive feedback genetic circuit, which consists of a double negative feedback circuit and an additional positive feedback loop(APFL). We study effect of substrate concentration on gene expression in the single and the networked systems with APFLs, respectively. We find that substrate concentration can tune stochastic switch behavior in the signal system and then we explore relationship of substrate concentration with positive feedback strength in aspect of stochastic switch behavior. Furthermore, we also discuss gene expression and stochastic switch behavior in the networked systems with APFLs. Based on analysis in the networked systems, we discover that genes express in some specific cells and do not express in the other cells when the expression achieves its steady state. These results can be used to well explain the character of regionalization in the expression of genes and the phenomenon of gene differentiation.展开更多
基金Funded by the National Natural Science Foundation of China(No.51262003)the Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China(No.1110908-10-Z)
文摘ZnMn_2O_4 thin films were deposited by a sol-gel technique onto a p+-Si substrate, and a RRAM device with the Ag/ZnMn_2O_4/p^+-Si structure was fabricated. The microstructure of ZnMn_2O_4 films and the resistive switching behavior of Ag/ZnMn_2O_4/p^+-Si device were investigated. ZnMn_2O_4 thin films had a spinel structure after annealing at 650 °C for 1 h. The Ag/ZnMn_2O_4/p^+-Si device showed unipolar and/or bipolar resistive switching behavior, exhibiting different ION/IOFF ratio and switching endurance properties. In bipolar resistive switching, high-resistance-state(HRS) conduction was dominated by the space-charge-limited conduction mechanism, whereas the filament conduction mechanism dictated the low resistance state(LRS). For unipolar resistive switching, HRS and LRS were controlled by the filament conduction mechanism. For bipolar resistive switching, the conduction process can be explained by the space-charge region of the p-n junction.
基金supported by the National Natural Science Foundation of China(62304172,62188102,and 62274130)the Natural Science Basic Research Program of Shaanxi(2022JQ-582 and 2022JQ-684)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2021A1515110020)the Fundamental Research Funds for the Central Universities(ZYTS24119)the Scientific Research Program Foundation of Shaanxi Provincial Education Department(22JK0564)。
文摘As a critical command center in organisms,the brain can execute multiple intelligent interactions through neural networks,including memory,learning and cognition.Recently,memristive-based neuromorphic devices have been widely developed as promising technologies to build artificial synapses and neurons for neural networks.However,multiple information interactions in artificial intelligence devices potentially pose threats to information security.Herein,a transient form of heterogeneous memristor with a stacked structure of Ag/MgO/SiN_(x)/W is proposed,in which both the reconfigurable resistive switching behavior and volatile threshold switching characteristics could be realized by adjusting the thickness of the SiN_(x)layer.The underlying resistive switching mechanism of the device was elucidated in terms of filamentary and interfacial effects.Representative neural functions,including short-term plasticity(STP),the transformation from STP to long-term plasticity,and integrate-and-fire neuron functions,have been successfully emulated in memristive devices.Moreover,the dissolution kinetics associated with underlying transient behaviors were explored,and the water-assisted transfer printing technique was exploited to build transient neuromorphic device arrays on the water-dissolvable poly(vinyl alcohol)substrate,which were able to formless disappear in deionized water after 10-s dissolution at room temperature.This transient form of memristive-based neuromorphic device provides an important step toward information security reinforcement for artificial neural network applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.61374150 and 61374171)the State Key Program of the National Natural Science Foundation of China(Grant No.61134012)+1 种基金the National Basic Research Program of China(Grant No.2011CB710606)the Fundamental Research Funds for the Central Universities,China(Grant No.2013TS126)
文摘The memristor, as the fourth basic circuit element, has drawn worldwide attention since its physical implementation was released by HP Labs in 2008. However, at the nano-scale, there are many difficulties for memristor physical realization. So a better understanding and analysis of a good model will help us to study the characteristics of a memristor. In this paper, we analyze a possible mechanism for the switching behavior of a memristor with a Pt/TiO2/Pt structure, and explain the changes of electronic barrier at the interface of Pt/TiO2. Then, a quantitative analysis about each parameter in the exponential model of memristor is conducted based on the calculation results. The analysis results are validated by simulation results. The efforts made in this paper will provide researchers with theoretical guidance on choosing appropriate values for(α, β, χ, γ) in this exponential model.
基金Funded by the National Natural Science Foundation of China(51262003)the Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China(No.1110908-10-Z)
文摘ZnMn_2O_4 films for resistance random access memory（RRAM） were fabricated with different device structures by magnetron sputtering. The effects of electrode on I-V characteristics, resistance switching behavior, endurance and retention characteristics of ZnMn_2O_4 films were investigated. The ZnMn_2O_4 films, using p-Si and Pt as bottom electrode, exhibit bipolar resistive switching（BRS） behavior dominated by the space-charge-limited conduction（SCLC） mechanism in the high resistance state（HRS） and the filament conduction mechanism in the low resistance state（LRS）, but the ZnMn_2O_4 films using n-Si as bottom electrodes exhibit both bipolar and unipolar resistive switching behaviors controlled by the Poole-Frenkel（P-F） conduction mechanism in both HRS and LRS. Ag/ZnMn_2O_4/p-Si device possesses the best endurance and retention characteristics, in which the number of stable repetition switching cycle is over 1000 and the retention time is longer than 106 seconds. However, the highest RHRS/R_（LRS） ratio of 104 and the lowest V_（ON） and V_（OFF） of 3.0 V have been observed in Ag/ZnMn_2O_4/Pt device. Though the Ag/ZnMn_2O_4/n-Si device also possesses the highest RHRS/R_（LRS） ratio of 104, but the highest values of V_（ON）,V_（OFF）, RHRS and R_（LRS）, as well as the poor endurance and retention characteristics.
基金supported by the grants from the National Science Foundation of China(Nos. 91132709 and 31130027)
文摘Sugar and protein are the major macronutrients＇ sources, and their balanced intake is important for animal＇s health. It has been observed that animals are able to change food preference in an imbalanced nutritional condition to selectively consume nutrients that are deficient in the body （Dethier, 1976）. Early studies in both Drosophila and mouse have demonstrated that animals exhibit food rejection to imbalanced diets lacking essential amino acids （Hao et al., 2005; Bjordal et al., 2014）. Furthermore, the food preference change upon protein depri- vation has been characterized using a two choice assay in Drosophila （Ribeiro and Dickson, 2010; Vargas et al., 2010）. Different from protein food, sugar is the main energy source, and sugar deficiency severely affects animal survival （Lee et al., 2008）. However, whether animals adopt a strategy of fast food preference switch upon sugar deprivation had not been investigated, and the neural mechanisms underlying this behavior regulation remain poorly understood.
基金financial support from the Natural Science Foundation of Henan Province(No.222300420501)the Science and Technology Project of Henan Province(No.212102210549)+1 种基金the Key Scientific Research Project of Higher Education of Henan Province(No.22A430007)National College Students Innovation and Entrepreneurship Training Program(No.202110482010)。
文摘Three novel dithienylethenes modified by bifluoroboron β-diketonate fragments have been successfully developed. Upon blue light irradiation, they reached photostationary state within 2-5 s, as well as 100% conversion ratio and photocyclization quantum yield of > 0.70. Such fascinating photochromism were endowed by collaborative role of electron-withdrawing effect of BF_(2)bdk group to reduce HOMO-LUMO electronic gap for the open isomer, together with intramolecular hydrogen bonds and CH-π interactions favoring antiparallel conformation fixation. Moreover, they displayed specific discrimination and photoswitchable bacterial imaging for S. aureus.
基金supported by the National Natural Science Foundation of China(71871172:Model of Risk knowledge acquisition and Platform governance in FinTech based on deep learning72171184:Grey Private Knowledge model of security and trusted BI on the federal Learning Perspective).
文摘Central banks worldwide have started researching and developing central bank digital currencies(CBDCs).In the digital economy context,concerns regarding the integrity,competition,and privacy of CBDC systems have also gradually emerged.Against this backdrop,this study aims to evaluate users’willingness to use China’s digital currency electronic payment(DCEP)system,a digital payment and processing network,and its influencing factors by comprehensively considering and comparing the characteristics of cash and third-party payment services.Combining the push-pull-mooring frame-work(PPM)and task-technology fit(TTF)theory,we discuss the scenarios and mecha-nisms that may inspire users’DCEP adoption intention through an empirical study.The results reveal that privacy concerns regarding the original payment methods and technology-task fitting level of DCEP positively impact users’willingness to adopt DCEP.The technical characteristics of DCEP,users’payment requirements,and government support positively affect users’adoption intention by influencing the task-technology fitting degree of DCEP.Switching cost significantly and negatively impacts adop-tion intention,whereas relative advantage exhibits no significant effect.This research contributes to a better understanding of the factors that influence switching intentions and the actual use of DCEP,and provides policy guidance on promoting the efficiency and effectiveness of DCEP.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFB0800401)the National Natural Science Foundation of China(Grant Nos.61773153,61621003,61532020,11472290,and 61472027)
文摘In gene regulatory networks, gene regulation loops often occur with multiple positive feedback, multiple negative feedback and coupled positive and negative feedback forms. In above gene regulation loops, auto-activation loops are ubiquitous regulatory motifs. This paper aims to investigate a two-component dual-positive feedback genetic circuit, which consists of a double negative feedback circuit and an additional positive feedback loop(APFL). We study effect of substrate concentration on gene expression in the single and the networked systems with APFLs, respectively. We find that substrate concentration can tune stochastic switch behavior in the signal system and then we explore relationship of substrate concentration with positive feedback strength in aspect of stochastic switch behavior. Furthermore, we also discuss gene expression and stochastic switch behavior in the networked systems with APFLs. Based on analysis in the networked systems, we discover that genes express in some specific cells and do not express in the other cells when the expression achieves its steady state. These results can be used to well explain the character of regionalization in the expression of genes and the phenomenon of gene differentiation.
