As artificial intelligence and big data become increasingly prevalent, resistive random-access memory (RRAM) has become one of the most promising alternatives for storing massive amounts of data. In this study, we emp...As artificial intelligence and big data become increasingly prevalent, resistive random-access memory (RRAM) has become one of the most promising alternatives for storing massive amounts of data. In this study, we employed high-quality crystalline TiN/Al_(2)O_(3)/BaTiO_(3)/Pt RRAM with an optimized thin Al_(2)O_(3) interlayer around 12 nm thick prepared using atomic layer deposition since the thickness of the interlayer affects the memory window size. After insertion of the Al_(2)O_(3) interlayer, the novel RRAM exhibited outstanding uniform resistive switching voltage and the ON/OFF memory window drastically increased from 10 to 103 without any discernible decline in performance. Moreover, the low-resistance state and high-resistance state operating current values decreased by almost one order and three orders of magnitude, respectively, thereby decreasing the power consumption for the RESET and SET processes by more than three and almost one order of magnitude, respectively. The device also exhibits multilevel resistive switching behavior when varying the applied voltage. Finally, we also developed a 6 6 crossbar array which demonstrated consistent and reliable resistive switching behavior with minimal variation. Hence, our approach holds great promise for producing state-of-the-art non-volatile resistive switching devices.展开更多
Moles exhibit highly effective capabilities due to their unique body structures and digging techniques,making them ideal models for biomimetic research.However,a major challenge for mole-inspired robots lies in overco...Moles exhibit highly effective capabilities due to their unique body structures and digging techniques,making them ideal models for biomimetic research.However,a major challenge for mole-inspired robots lies in overcoming resistance in granular media when burrowing with forelimbs.In the absence of effective forepaw design strategies,most robotic designs rely on increased power to enhance performance.To address this issue,this paper employs Resistive Force Theory to optimize mole-inspired forepaws,aiming to enhance burrowing efficiency.By analyzing the relationship between geometric parameters and burrowing forces,we propose several forepaw design variations.Through granular resistance assessments,an effective forepaw configuration is identified and further refined using parameters such as longitudinal and transverse curvature.Subsequently,the Particle Swarm Optimization algorithm is applied to determine the optimal forepaw design.In force-loading tests,the optimized forepaw demonstrated a 79.44%reduction in granular lift force and a 22.55%increase in propulsive force compared with the control group.In robotic burrowing experiments,the optimized forepaw achieved the longest burrow displacement(179.528 mm)and the lowest burrowing lift force(0.9355 mm/s),verifying its effectiveness in reducing the lift force and enhancing the propulsive force.展开更多
The exploratory synthesis and structural characterization of twodimensional(2D)honeycomb structured Ru-based compounds are key focuses in inorganic materials research,due to the various exotic electronic states arisin...The exploratory synthesis and structural characterization of twodimensional(2D)honeycomb structured Ru-based compounds are key focuses in inorganic materials research,due to the various exotic electronic states arising from the interplay of electron correlations and spinorbit coupling.Among these compounds,α-RuCl_(3) and RuBr_(3) are considered as the most promising candidates for quantum spin liquid(QSL)materials[1–3].As a homolog,α-RuI3 has attracted significant interest,but it still remains relatively unexplored.Recently,it was synthesized by high-temperature and high-pressure solid-state reaction,but reported to be different crystal structures by independent groups.Ni et al.and Nawa et al.considerα-RuI3 to be R-3(3R)and P-31c(2H)space group,respectively[4,5].Both structures have typical 2D characteristics,in which the edge-sharing RuI6 octahedra form honeycomb layers stacked along the c-axis.The primary difference lies in that the honeycomb layers stack in ABCABC mode in the 3R phase,while in ABAB mode in the 2H phase(Fig.S1).Yang et al.discussed the stability of 3R and 2H polymorphs in terms of the total energies and dynamics,finding both structures are stable.However,the total energy of the 2H phase is slightly higher,2.58 meV than that of the 3R analog[6].When it comes to the conductivity behaviour,α-RuCl3 andα-RuBr_(3) are semiconductors as normally observed in QSL materials.In contrast,α-RuI_(3) exhibits metallic response.In 2D materials,the band structure may be drastically modified by altering the stacking order[7].Hence,determining the crystal structure ofα-RuI_(3) is urgently required,which is a key step in comprehensive and in-depth analysis of its physical properties.展开更多
BACKGROUND Acute kidney injury(AKI)is a frequent complication after liver transplantation(LT).How to realize the early diagnosis of AKI,perform active intervention,and reduce the mortality of post-LT patients is an ur...BACKGROUND Acute kidney injury(AKI)is a frequent complication after liver transplantation(LT).How to realize the early diagnosis of AKI,perform active intervention,and reduce the mortality of post-LT patients is an urgent problem to be solved.AIM To investigate the accuracy of hepatorenal index(HRI)and renal resistive index(RRI)in monitoring of early AKI after LT.METHODS This observational study included adult deceased-donor LT recipients at our center between February 2022 and February 2023 with no preoperative renal dysfunction.The HRI and RRI were recorded once per day in the postoperative period through to postoperative day(POD)7.We followed up with the patients at 1 month after LT.The patients were divided into the AKI and non-AKI groups according to the Kidney Disease Improving Global Outcomes criteria.RESULTS Of 121 patients were included in the study(mean age:50.18±8.88years;female:17.36%).AKI developed in 53 patients(43.80%).The AKI and non-AKI groups were similar in terms of their baseline characteristics.An HRI of≤1.12 on POD 1 detected AKI with a sensitivity of 62.30%and a specificity of 87.80%[area under the receiver operating characteristic curve(AUC)=0.801,P<0.01].An RRI of≥0.65 on POD 1 detected AKI with a sensitivity of 87.80%and a specificity of 67.60%(AUC=0.825,P<0.01).The HRI combined with the RRI was more effective at detecting AKI than either the HRI or RRI alone(AUC=0.890,P<0.01).The HRI increased as AKI resolved while the RRI decreased as AKI resolved.CONCLUSION The HRI and RRI are non-invasive bedside indices that can identify the occurrence and recovery of early AKI after LT.展开更多
A CMOS compatible RRAM device with TaN/Ta/TaOx/Ta N structure was proposed for nonvolatile memory applications.Excellent resistive switching characteristics,including low operation voltages(<1 V),low operation curr...A CMOS compatible RRAM device with TaN/Ta/TaOx/Ta N structure was proposed for nonvolatile memory applications.Excellent resistive switching characteristics,including low operation voltages(<1 V),low operation current(<100μA),good programming/erasing endurance(>10^(6) cycles),satisfactory uniformity,and reliable data retention,have been demonstrated.Furthermore,all of the elements in the fabricated Ta N/Ta/Ta Ox/Ta N devices are highly compatible with modern CMOS manufacturing process,showing promising application in the next generation of nonvolatile memory.展开更多
This review summarizes the mechanism and performance of metal oxide based resistive switching memory. The origin of resistive switching （RS） behavior can be roughly classified into the conducting filament type and t...This review summarizes the mechanism and performance of metal oxide based resistive switching memory. The origin of resistive switching （RS） behavior can be roughly classified into the conducting filament type and the interface type. Here, we adopt the filament type to study the metal oxide based resistive switch- ing memory, which considers the migration of metallic cations and oxygen vacancies, as well as discuss two main mechanisms including the electrochemical metallization effect （ECM） and valence change memory effect （VCM）. At the light of the influence of the electrode materials and switching layers on the RS char- acteristics, an overview has also been given on the performance parameters including the uniformity, endurance, the retention, and the multi-layer storage. Especially, we mentioned ITO （indium tin oxide） electrode and discussed the novel RS characteristics related with ITO. Finally, the challenges resistive random access memory （RRAM） device is facing, as well as the future development trend, are expressed.展开更多
In this paper, the bipolar resistive switching characteristic is reported in Ti/ZrO2/Pt resistive switching memory de- vices. The dominant mechanism of resistive switching is the formation and rupture of the conductiv...In this paper, the bipolar resistive switching characteristic is reported in Ti/ZrO2/Pt resistive switching memory de- vices. The dominant mechanism of resistive switching is the formation and rupture of the conductive filament composed of oxygen vacancies. The conduction mechanisms for low and high resistance states are dominated by the ohmic conduc- tion and the trap-controlled space charge limited current （SCLC） mechanism, respectively. The effect of a set compliance current on the switching parameters is also studied： the low resistance and reset current are linearly dependent on the set compliance current in the log-log scale coordinate; and the set and reset voltage increase slightly with the increase of the set compliance current. A series circuit model is proposed to explain the effect of the set compliance current on the resistive switching behaviors.展开更多
In this paper, a WO3-based resistive random access memory device composed of a thin film of WO3 sandwiched between a copper top and a platinum bottom electrodes is fabricated by electron beam evaporation at room tempe...In this paper, a WO3-based resistive random access memory device composed of a thin film of WO3 sandwiched between a copper top and a platinum bottom electrodes is fabricated by electron beam evaporation at room temperature. The reproducible resistive switching, low power consumption, multilevel storage possibility, and good data retention characteristics demonstrate that the Cu/WO3/Pt memory device is very promising for future nonvolatile memory applications. The formation and rupture of localised conductive filaments is suggested to be responsible for the observed resistive switching behaviours.展开更多
We demonstrate the polarization of resistive switching for a Cu/VOx/Cu memory cell.The switching behaviors of Cu/VOx/Cu cell are tested by using a semiconductor device analyzer（Agilent B1500A）,and the relative micro...We demonstrate the polarization of resistive switching for a Cu/VOx/Cu memory cell.The switching behaviors of Cu/VOx/Cu cell are tested by using a semiconductor device analyzer（Agilent B1500A）,and the relative micro-analysis of I-V characteristics of VOx/Cu is characterized by using a conductive atomic force microscope（CAFM）.The I-V test results indicate that both the forming and the reversible resistive switching between low resistance state（LRS） and high resistance state（HRS） can be observed under either positive or negative sweep.The CAFM images for LRS and HRS directly exhibit evidence for the formation and rupture of filaments based on positive or negative voltage.The Cu/VOx/Cu sandwiched structure exhibits reversible resistive switching behavior and shows potential applications in the next generation of nonvolatile memory.展开更多
The behavior of resistive short defects in FPGA interconnects is investigated through simulation and theoretical analysis.The results show that these defects result in timing failures and even Boolean faults for small...The behavior of resistive short defects in FPGA interconnects is investigated through simulation and theoretical analysis.The results show that these defects result in timing failures and even Boolean faults for small defect resistance values.The best detection situations for large resistance defect happen when the path under test makes a v-to-v′ transition and another path causing short faults remains at value v.Small defects can be detected easily through static analysis.Under the best test situations,the effects of supply voltage and temperature on test results are evaluated.The results verify that lower voltage helps to improve detectability.If short material has positive temperature coefficient,low temperature is better;otherwise,high temperature is better.展开更多
The electrical performance including breakdown voltage and turn-off speed of SOI-LIGBT is improved by incorporating a resistive field plate (RFP) and a p-MOSFET.The p-MOSFET is controlled by a signal detected from a p...The electrical performance including breakdown voltage and turn-off speed of SOI-LIGBT is improved by incorporating a resistive field plate (RFP) and a p-MOSFET.The p-MOSFET is controlled by a signal detected from a point of the RFP.During the turning-off of the IGBT,the p-MOSFET is turned on,which provides a channel for the excessive carriers to flow out of the drift region and prevents the carriers from being injected into the drift region.At the same time,the electric field affected by the RFP makes the excessive carriers flow through a wider region,which almost eliminates the second phase of the turning-off of the SOI-LIGBT caused by the substrate bias.Faster turn-off speed is achieved by above two factors.During the on state of the IGBT,the p-MOSFET is off,which leads to an on-state performance like normal one.At least,the increase of the breakdown voltage for 25% and the decrease of the turn-off time for 65% can be achieved by this structure as can be verified by the numerical simulation results.展开更多
The electric-pulse-induced resistive switching effect is studied for Tio.s5Cro.15Ox （TCO） films grown on Ir-Si substrates by pulsed laser deposition. Such a TCO device exhibits bipolar switching behaviour with an el...The electric-pulse-induced resistive switching effect is studied for Tio.s5Cro.15Ox （TCO） films grown on Ir-Si substrates by pulsed laser deposition. Such a TCO device exhibits bipolar switching behaviour with an electric-pulse- induced resistance ratio as large as about 1000% and threshold voltages smaller than 2 V. The resistive switching characteristics may be understood by resistance changes of a Schottky junction composed of a metal and an n-type semiconductor, and its nonvolatility is attributed to the movement of oxygen vacancies near the interface.展开更多
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 dat...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.展开更多
Transient electronics has attracted interest as an emerging technology to solve electronic-waste problem,due to its physically vanishing ability in solution.Here in this work,we demonstrate a flexible and degradable t...Transient electronics has attracted interest as an emerging technology to solve electronic-waste problem,due to its physically vanishing ability in solution.Here in this work,we demonstrate a flexible and degradable transient resistive switching(RS) memory device with simple structure of Cu/sodium alginate(SA)/ITO.The device presents excellent RS characteristics as well as high flexibility,including low operating voltage(<1.5 V) and multilevel RS behavior.No performance degradation occurs after bending the device 50 times.Moreover,our device can be absolutely dissolved in deionized water.The proposed SA-based transient memory device has great potential for the development of green and security memory devices.展开更多
Graphene-based resistive random access memory （GRRAM） has grasped researchers＇ attention due to its merits com- pared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can...Graphene-based resistive random access memory （GRRAM） has grasped researchers＇ attention due to its merits com- pared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can be divided into two categories： graphene RRAM and graphene oxide （GO）/reduced graphene oxide （rGO） RRAM. Using graphene as the electrode, GRRAM can own many good characteristics, such as low power consumption, higher density, transparency, SET voltage modulation, high uniformity, and so on. Graphene flakes sandwiched between two dielectric layers can lower the SET voltage and achieve multilevel switching. Moreover, the GRRAM with rGO and GO as the dielectric or electrode can be simply fabricated. Flexible and high performance RRAM and GO film can be modified by adding other materials layer or making a composite with polymer, nanoparticle, and 2D materials to further improve the performance. Above all, GRRAM shows huge potential to become the next generation memory.展开更多
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 ...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.展开更多
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 constr...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.展开更多
AIM:To evaluate the clinical significance of cystatin C and renal resistive index for the determination of renal function in patients with liver cirrhosis.METHODS:We conducted a study of 63 patients with liver cirrhos...AIM:To evaluate the clinical significance of cystatin C and renal resistive index for the determination of renal function in patients with liver cirrhosis.METHODS:We conducted a study of 63 patients with liver cirrhosis.A control group comprised of 30 age and gender-matched healthy persons.Serum cystatin C was determined in all study subjects and renal Doppler ultrasonography was made.Estimated glomerular filtration rate from serum creatinine(GFRCr)and cystatin C(GFRCys)was calculated.RESULTS:We confirmed significant differences in val-ues of cystatin C between patients with different stages of liver cirrhosis according to Child-Pugh(P=0.01),and a significant correlation with model of end stage liver disease(MELD)score(rs=0.527,P<0.001).More patients with decreased glomerular filtration rate were identified based on GFRCys than on GFRCr(P<0.001).Significantly higher renal resistive index was noted in Child-Pugh C than in A(P<0.001)and B stage(P=0.001).Also,a significant correlation between renal resistive index and MELD score was observed(rs=0.607,P<0.001).Renal resistive index correlated significantly with cystatin C(rs=0.283,P=0.028)and showed a negative correlation with GFRCys(rs=-0.31,P=0.016).CONCLUSION:Cystatin C may be a more reliable marker for assessment of liver insufficiency.Additionally,cystatin C and renal resistive index represent sensitive indicators of renal dysfunction in patients with liver cirrhosis.展开更多
According to the dimensionless formulae of DOP(depth of penetration) of a rigid projectile into different targets,the resistive force which a target exerts on the projectile during the penetration of rigid projectile ...According to the dimensionless formulae of DOP(depth of penetration) of a rigid projectile into different targets,the resistive force which a target exerts on the projectile during the penetration of rigid projectile is theoretically analyzed.In particular,the threshold V_C of impact velocity applicable for the assumption of constant resistive force is formulated through impulse analysis.The various values of V_C corresponding to different pairs of projectile-target are calculated,and the consistency of the relative test data and numerical results is observed.展开更多
The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth...The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO_2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO_2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 10~4 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO_2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based Re RAM device in the future.展开更多
基金supported by the National Research Foundation of Korea funded by the Korean Government(grant No.RS-2023-00208801).
文摘As artificial intelligence and big data become increasingly prevalent, resistive random-access memory (RRAM) has become one of the most promising alternatives for storing massive amounts of data. In this study, we employed high-quality crystalline TiN/Al_(2)O_(3)/BaTiO_(3)/Pt RRAM with an optimized thin Al_(2)O_(3) interlayer around 12 nm thick prepared using atomic layer deposition since the thickness of the interlayer affects the memory window size. After insertion of the Al_(2)O_(3) interlayer, the novel RRAM exhibited outstanding uniform resistive switching voltage and the ON/OFF memory window drastically increased from 10 to 103 without any discernible decline in performance. Moreover, the low-resistance state and high-resistance state operating current values decreased by almost one order and three orders of magnitude, respectively, thereby decreasing the power consumption for the RESET and SET processes by more than three and almost one order of magnitude, respectively. The device also exhibits multilevel resistive switching behavior when varying the applied voltage. Finally, we also developed a 6 6 crossbar array which demonstrated consistent and reliable resistive switching behavior with minimal variation. Hence, our approach holds great promise for producing state-of-the-art non-volatile resistive switching devices.
基金financially supported in-part by the National Natural Science Foundation of China(52275011)the Natural Science Foundation of Guangdong Province(2023B1515020080)+3 种基金the Natural Science Foundation of Guangzhou(2024A04J2552)the Fundamental Research Funds for the Central Universities,the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(CAST)(2021QNRC001)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515011253)the Higher Education Institution Featured Innovation Project of Department of Education of Guangdong Province(GrantNo.2023KTSCX138).
文摘Moles exhibit highly effective capabilities due to their unique body structures and digging techniques,making them ideal models for biomimetic research.However,a major challenge for mole-inspired robots lies in overcoming resistance in granular media when burrowing with forelimbs.In the absence of effective forepaw design strategies,most robotic designs rely on increased power to enhance performance.To address this issue,this paper employs Resistive Force Theory to optimize mole-inspired forepaws,aiming to enhance burrowing efficiency.By analyzing the relationship between geometric parameters and burrowing forces,we propose several forepaw design variations.Through granular resistance assessments,an effective forepaw configuration is identified and further refined using parameters such as longitudinal and transverse curvature.Subsequently,the Particle Swarm Optimization algorithm is applied to determine the optimal forepaw design.In force-loading tests,the optimized forepaw demonstrated a 79.44%reduction in granular lift force and a 22.55%increase in propulsive force compared with the control group.In robotic burrowing experiments,the optimized forepaw achieved the longest burrow displacement(179.528 mm)and the lowest burrowing lift force(0.9355 mm/s),verifying its effectiveness in reducing the lift force and enhancing the propulsive force.
基金supported by the National Natural Science Foundation of China(No.22090041)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2017ZT07C069)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2022B1515120014)the Natural Science Foundation of Zhejiang Province(No.LQ21A040010).
文摘The exploratory synthesis and structural characterization of twodimensional(2D)honeycomb structured Ru-based compounds are key focuses in inorganic materials research,due to the various exotic electronic states arising from the interplay of electron correlations and spinorbit coupling.Among these compounds,α-RuCl_(3) and RuBr_(3) are considered as the most promising candidates for quantum spin liquid(QSL)materials[1–3].As a homolog,α-RuI3 has attracted significant interest,but it still remains relatively unexplored.Recently,it was synthesized by high-temperature and high-pressure solid-state reaction,but reported to be different crystal structures by independent groups.Ni et al.and Nawa et al.considerα-RuI3 to be R-3(3R)and P-31c(2H)space group,respectively[4,5].Both structures have typical 2D characteristics,in which the edge-sharing RuI6 octahedra form honeycomb layers stacked along the c-axis.The primary difference lies in that the honeycomb layers stack in ABCABC mode in the 3R phase,while in ABAB mode in the 2H phase(Fig.S1).Yang et al.discussed the stability of 3R and 2H polymorphs in terms of the total energies and dynamics,finding both structures are stable.However,the total energy of the 2H phase is slightly higher,2.58 meV than that of the 3R analog[6].When it comes to the conductivity behaviour,α-RuCl3 andα-RuBr_(3) are semiconductors as normally observed in QSL materials.In contrast,α-RuI_(3) exhibits metallic response.In 2D materials,the band structure may be drastically modified by altering the stacking order[7].Hence,determining the crystal structure ofα-RuI_(3) is urgently required,which is a key step in comprehensive and in-depth analysis of its physical properties.
基金Supported by the Clinical+X Scientific Research Project of Affiliated Hospital of Qingdao University,No.QYFY+X202101060Natural Science Foundation of Shandong Province,No.ZR2023MH240.
文摘BACKGROUND Acute kidney injury(AKI)is a frequent complication after liver transplantation(LT).How to realize the early diagnosis of AKI,perform active intervention,and reduce the mortality of post-LT patients is an urgent problem to be solved.AIM To investigate the accuracy of hepatorenal index(HRI)and renal resistive index(RRI)in monitoring of early AKI after LT.METHODS This observational study included adult deceased-donor LT recipients at our center between February 2022 and February 2023 with no preoperative renal dysfunction.The HRI and RRI were recorded once per day in the postoperative period through to postoperative day(POD)7.We followed up with the patients at 1 month after LT.The patients were divided into the AKI and non-AKI groups according to the Kidney Disease Improving Global Outcomes criteria.RESULTS Of 121 patients were included in the study(mean age:50.18±8.88years;female:17.36%).AKI developed in 53 patients(43.80%).The AKI and non-AKI groups were similar in terms of their baseline characteristics.An HRI of≤1.12 on POD 1 detected AKI with a sensitivity of 62.30%and a specificity of 87.80%[area under the receiver operating characteristic curve(AUC)=0.801,P<0.01].An RRI of≥0.65 on POD 1 detected AKI with a sensitivity of 87.80%and a specificity of 67.60%(AUC=0.825,P<0.01).The HRI combined with the RRI was more effective at detecting AKI than either the HRI or RRI alone(AUC=0.890,P<0.01).The HRI increased as AKI resolved while the RRI decreased as AKI resolved.CONCLUSION The HRI and RRI are non-invasive bedside indices that can identify the occurrence and recovery of early AKI after LT.
基金Project supported by the Key Research and Development Program of Gansu Province-Industrial Project(Grant No.25YFGA005)。
文摘A CMOS compatible RRAM device with TaN/Ta/TaOx/Ta N structure was proposed for nonvolatile memory applications.Excellent resistive switching characteristics,including low operation voltages(<1 V),low operation current(<100μA),good programming/erasing endurance(>10^(6) cycles),satisfactory uniformity,and reliable data retention,have been demonstrated.Furthermore,all of the elements in the fabricated Ta N/Ta/Ta Ox/Ta N devices are highly compatible with modern CMOS manufacturing process,showing promising application in the next generation of nonvolatile memory.
基金financial support from the National Natural Science Foundation of China(Nos.61474039 and 51572002)the Nature Science Foundation(Key Project) of Hubei Province (No.2015CFA052)
文摘This review summarizes the mechanism and performance of metal oxide based resistive switching memory. The origin of resistive switching （RS） behavior can be roughly classified into the conducting filament type and the interface type. Here, we adopt the filament type to study the metal oxide based resistive switch- ing memory, which considers the migration of metallic cations and oxygen vacancies, as well as discuss two main mechanisms including the electrochemical metallization effect （ECM） and valence change memory effect （VCM）. At the light of the influence of the electrode materials and switching layers on the RS char- acteristics, an overview has also been given on the performance parameters including the uniformity, endurance, the retention, and the multi-layer storage. Especially, we mentioned ITO （indium tin oxide） electrode and discussed the novel RS characteristics related with ITO. Finally, the challenges resistive random access memory （RRAM） device is facing, as well as the future development trend, are expressed.
基金supported by the National Basic Research Program of China(Grant No.2011CBA00606)the National Natural Science Foundation of China(Grant Nos.61106106,11304237,61376099,and 11235008)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant Nos.20130203130002 and 20110203110012)
文摘In this paper, the bipolar resistive switching characteristic is reported in Ti/ZrO2/Pt resistive switching memory de- vices. The dominant mechanism of resistive switching is the formation and rupture of the conductive filament composed of oxygen vacancies. The conduction mechanisms for low and high resistance states are dominated by the ohmic conduc- tion and the trap-controlled space charge limited current （SCLC） mechanism, respectively. The effect of a set compliance current on the switching parameters is also studied： the low resistance and reset current are linearly dependent on the set compliance current in the log-log scale coordinate; and the set and reset voltage increase slightly with the increase of the set compliance current. A series circuit model is proposed to explain the effect of the set compliance current on the resistive switching behaviors.
基金Project supported by the National Basic Research Program of China(Grant Nos.2008CB925002 and 2010CB934200)the National Natural Science Foundation of China(Grant Nos.60825403 and 50972160)the National High Technology Research and Development Program of China(Grant No.2009AA03Z306)
文摘In this paper, a WO3-based resistive random access memory device composed of a thin film of WO3 sandwiched between a copper top and a platinum bottom electrodes is fabricated by electron beam evaporation at room temperature. The reproducible resistive switching, low power consumption, multilevel storage possibility, and good data retention characteristics demonstrate that the Cu/WO3/Pt memory device is very promising for future nonvolatile memory applications. The formation and rupture of localised conductive filaments is suggested to be responsible for the observed resistive switching behaviours.
基金Project supported by the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-11-1064)the Young Scientists Fund of the National Natural Science Foundation of China (Grant Nos. 61101055,61274113,and 11204212)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20100032120029)Tianjin Natural Science Foundation of China (Grant No. 10SYSYJC27700)
文摘We demonstrate the polarization of resistive switching for a Cu/VOx/Cu memory cell.The switching behaviors of Cu/VOx/Cu cell are tested by using a semiconductor device analyzer（Agilent B1500A）,and the relative micro-analysis of I-V characteristics of VOx/Cu is characterized by using a conductive atomic force microscope（CAFM）.The I-V test results indicate that both the forming and the reversible resistive switching between low resistance state（LRS） and high resistance state（HRS） can be observed under either positive or negative sweep.The CAFM images for LRS and HRS directly exhibit evidence for the formation and rupture of filaments based on positive or negative voltage.The Cu/VOx/Cu sandwiched structure exhibits reversible resistive switching behavior and shows potential applications in the next generation of nonvolatile memory.
文摘The behavior of resistive short defects in FPGA interconnects is investigated through simulation and theoretical analysis.The results show that these defects result in timing failures and even Boolean faults for small defect resistance values.The best detection situations for large resistance defect happen when the path under test makes a v-to-v′ transition and another path causing short faults remains at value v.Small defects can be detected easily through static analysis.Under the best test situations,the effects of supply voltage and temperature on test results are evaluated.The results verify that lower voltage helps to improve detectability.If short material has positive temperature coefficient,low temperature is better;otherwise,high temperature is better.
文摘The electrical performance including breakdown voltage and turn-off speed of SOI-LIGBT is improved by incorporating a resistive field plate (RFP) and a p-MOSFET.The p-MOSFET is controlled by a signal detected from a point of the RFP.During the turning-off of the IGBT,the p-MOSFET is turned on,which provides a channel for the excessive carriers to flow out of the drift region and prevents the carriers from being injected into the drift region.At the same time,the electric field affected by the RFP makes the excessive carriers flow through a wider region,which almost eliminates the second phase of the turning-off of the SOI-LIGBT caused by the substrate bias.Faster turn-off speed is achieved by above two factors.During the on state of the IGBT,the p-MOSFET is off,which leads to an on-state performance like normal one.At least,the increase of the breakdown voltage for 25% and the decrease of the turn-off time for 65% can be achieved by this structure as can be verified by the numerical simulation results.
基金Project supported by NASA,the State of Texas through the Center for Advanced Materials,Sharp Laboratories of America,Semiconductor Research Corporation,the R.A.Welch Foundation (Grant No.#E-632)the National Natural Science Foundation of China (Grant No.11074109)+2 种基金the Natural Science Foundation of Jiangsu Province of China (Grant No.SBK200920627)the National Basic Research Program of China (Grant No.2010CB923404)the National "Climbing" Program of China (Grant No.91021003)
文摘The electric-pulse-induced resistive switching effect is studied for Tio.s5Cro.15Ox （TCO） films grown on Ir-Si substrates by pulsed laser deposition. Such a TCO device exhibits bipolar switching behaviour with an electric-pulse- induced resistance ratio as large as about 1000% and threshold voltages smaller than 2 V. The resistive switching characteristics may be understood by resistance changes of a Schottky junction composed of a metal and an n-type semiconductor, and its nonvolatility is attributed to the movement of oxygen vacancies near the interface.
基金Project supported by the National Natural Science Foundation of China(Grant No.60921062)
文摘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.
基金Project supported by the Fund from the Ministry of Science and Technology of China(Grant No.2018YFE0118300)the National Natural Science Foundation of China(Grant Nos.11974072,51902048,61774031,and 61574031)+3 种基金the“111”Project,China(Grant No.B13013)the China Postdoctoral Science Foundation,China(Grant No.2019M661185)the Fundamental Research Funds for the Central Universities,China(Grant No.2412019QD015)Science Fund from the Jilin Province,China(Grant No.JJKH20201163KJ)。
文摘Transient electronics has attracted interest as an emerging technology to solve electronic-waste problem,due to its physically vanishing ability in solution.Here in this work,we demonstrate a flexible and degradable transient resistive switching(RS) memory device with simple structure of Cu/sodium alginate(SA)/ITO.The device presents excellent RS characteristics as well as high flexibility,including low operating voltage(<1.5 V) and multilevel RS behavior.No performance degradation occurs after bending the device 50 times.Moreover,our device can be absolutely dissolved in deionized water.The proposed SA-based transient memory device has great potential for the development of green and security memory devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61574083 and 61434001)the National Basic Research Program of China(Grant No.2015CB352101)+4 种基金the National Key Research and Development Program of China(Grant No.2016YFA0200404)the National Key Project of Science and Technology of China(Grant No.2011ZX02403-002)Special Fund for Agroscientic Research in the Public Interest of China(Grant No.201303107)the Independent Research Program of Tsinghua University,China(Grant No.2014Z01006)Advanced Sensor and Integrated System Lab of Tsinghua University Graduate School at Shenzhen,China(Grant No.ZDSYS20140509172959969)
文摘Graphene-based resistive random access memory （GRRAM） has grasped researchers＇ attention due to its merits com- pared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can be divided into two categories： graphene RRAM and graphene oxide （GO）/reduced graphene oxide （rGO） RRAM. Using graphene as the electrode, GRRAM can own many good characteristics, such as low power consumption, higher density, transparency, SET voltage modulation, high uniformity, and so on. Graphene flakes sandwiched between two dielectric layers can lower the SET voltage and achieve multilevel switching. Moreover, the GRRAM with rGO and GO as the dielectric or electrode can be simply fabricated. Flexible and high performance RRAM and GO film can be modified by adding other materials layer or making a composite with polymer, nanoparticle, and 2D materials to further improve the performance. Above all, GRRAM shows huge potential to become the next generation memory.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60921062)
文摘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.
基金Chenzhou Science and Technology Plan Project of China(Grant No.ZDYF2020159)Scientific Research Project of Hunan Provincial Department of Education(Grant No.21C0708)。
文摘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.
基金Supported by Ministry of Education,Science and Technological Development,Belgrade,Republic of Serbia,Project No.175036
文摘AIM:To evaluate the clinical significance of cystatin C and renal resistive index for the determination of renal function in patients with liver cirrhosis.METHODS:We conducted a study of 63 patients with liver cirrhosis.A control group comprised of 30 age and gender-matched healthy persons.Serum cystatin C was determined in all study subjects and renal Doppler ultrasonography was made.Estimated glomerular filtration rate from serum creatinine(GFRCr)and cystatin C(GFRCys)was calculated.RESULTS:We confirmed significant differences in val-ues of cystatin C between patients with different stages of liver cirrhosis according to Child-Pugh(P=0.01),and a significant correlation with model of end stage liver disease(MELD)score(rs=0.527,P<0.001).More patients with decreased glomerular filtration rate were identified based on GFRCys than on GFRCr(P<0.001).Significantly higher renal resistive index was noted in Child-Pugh C than in A(P<0.001)and B stage(P=0.001).Also,a significant correlation between renal resistive index and MELD score was observed(rs=0.607,P<0.001).Renal resistive index correlated significantly with cystatin C(rs=0.283,P=0.028)and showed a negative correlation with GFRCys(rs=-0.31,P=0.016).CONCLUSION:Cystatin C may be a more reliable marker for assessment of liver insufficiency.Additionally,cystatin C and renal resistive index represent sensitive indicators of renal dysfunction in patients with liver cirrhosis.
基金supported by the National Outstanding Young Scientist Foundation of China(11225213)Major Program of National Natural Science Foundation of China(Grant No.11390362)
文摘According to the dimensionless formulae of DOP(depth of penetration) of a rigid projectile into different targets,the resistive force which a target exerts on the projectile during the penetration of rigid projectile is theoretically analyzed.In particular,the threshold V_C of impact velocity applicable for the assumption of constant resistive force is formulated through impulse analysis.The various values of V_C corresponding to different pairs of projectile-target are calculated,and the consistency of the relative test data and numerical results is observed.
基金supported by the Natural Sciences and Engineering Research Council(NSERC)of CanadaThe financial support of the State Scholarship Fund of China(No.201506160061)
文摘The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO_2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO_2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 10~4 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO_2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based Re RAM device in the future.
