Near-equiatomic NiTi shape memory alloys are known to exhibit Lüders-type deformation associated with a stress-induced transformation.Many studies have been conducted in the past mainly focusing on the macroscopi...Near-equiatomic NiTi shape memory alloys are known to exhibit Lüders-type deformation associated with a stress-induced transformation.Many studies have been conducted in the past mainly focusing on the macroscopic characteristics of the phenomenon and some theories have been proposed in the literature to explain its mechanisms,but some aspects of this phenomenon are still unclear,particularly at the microscopic scale.This study investigated the local strain evolution during the initiation and propagation of Lüders band in a pseudoelastic NiTi alloy during tensile deformation by means of digital image correlation(DIC)analysis.Based on the evidence collected,distinct stages of Lüders band formation and propagation are defined and the corresponding local strain rates are obtained.These local strain rates are much higher than the global strain rate of the testing,giving insight to the mechanism of this phenomenon.展开更多
In this study,the high-strength pipe steel,i.e.X80,was heated at 260℃for half an hour followed by air cooling for thermal simulation of pipe coating process.During the uniaxial loading of the specified tension sample...In this study,the high-strength pipe steel,i.e.X80,was heated at 260℃for half an hour followed by air cooling for thermal simulation of pipe coating process.During the uniaxial loading of the specified tension samples,the migration behaviour of Lüders bands and the re-distribution of stress after strain ageing heat treatment were investigated using digital image correlation.Digital image correlation was adopted to characterise the local axial and shear strain fields of samples that were extracted from different locations across the wall thickness of the high-strength pipe steel,and electron backscatter diffraction was used to compare the evolution of crystallographic texture among these locations.Other characterisation methods regarding microstructure and mechanical properties were conducted meanwhile,including optical microscopy,scanning electron microscopy and X-ray diffraction to accurately define the detailed performances that strain ageing,i.e.being heated to 260℃for half an hour,has led to.The obtained results show that the Lüders band-related microstructure,dislocation density,lattice constant and texture vary at the different locations across the wall thickness and influence the fi nal mechanical properties of the selected high-strength pipe steel.展开更多
Editor's note: We are sorry that because of the over-crowded space in our last issue, we are delayed in presenting the second part of the report delivered by the CAS President Lu Yongxiang at the 2002 working conf...Editor's note: We are sorry that because of the over-crowded space in our last issue, we are delayed in presenting the second part of the report delivered by the CAS President Lu Yongxiang at the 2002 working conference of CAS. The report appears in two installments in this and the 1st issue of this volume.展开更多
Addition of Fe B C and Fe Mo B C m aster alloy pow ders to Fe Mo B Csintered steels can ac tivate the sintering process by liquid phase sintering . The for m ation of liquid ( α- Fe + ( Fe , Mo...Addition of Fe B C and Fe Mo B C m aster alloy pow ders to Fe Mo B Csintered steels can ac tivate the sintering process by liquid phase sintering . The for m ation of liquid ( α- Fe + ( Fe , Mo) 2 B+ Fe3( B, C) → L) i m proves m echanical properties of the steels , and ultim ate tensilestrengths of 684 774 M Pa , i m pact energy of 47 ±7 Jand elongation of 2 5 ±0 9 were ob tained . Optim u m a mount of liquid phase exists , and alarge a mount of liquid phase will re sult in the form ation of continuous netw ork of liquid phase that is detrim ental to strength andelongation .展开更多
Synthesis of a m m oniu m alu min u m carbonate hydroxide ( A A C H) w as investigated usinga m m oniu m alu min u m sulfate and a m moniu m hydro carbonate as the starting m aterials . Itw as found that A A C Hca...Synthesis of a m m oniu m alu min u m carbonate hydroxide ( A A C H) w as investigated usinga m m oniu m alu min u m sulfate and a m moniu m hydro carbonate as the starting m aterials . Itw as found that A A C Hcan be synthesized by adding a m m oniu m alu m inu m sulfate solution torapidly stirred a m moniu m hydro - carbonate solution at a tem perature of 30 ℃. A A C Hcantransfor m to α Al2 O3 co m pletely by calcining at 1100 ℃ for 1 hour , and the obtained po w ders , with a particle size of 100 n m , can be sintered to 98 99 % relative density at 1500 ℃for 2 hours .展开更多
We investigate the cross-sectional buckling of multi-concentric tubular nanomaterials, which are called multiwalled carbon nanotubes (MWNTs), using an analysis based on thin-shell theory. MWNTs under hydrostatic press...We investigate the cross-sectional buckling of multi-concentric tubular nanomaterials, which are called multiwalled carbon nanotubes (MWNTs), using an analysis based on thin-shell theory. MWNTs under hydrostatic pressure experience radial buckling. As a result of this, different buckling modes are obtained depending on the inter-tube separation d as well as the number of constituent tubes N and the innermost tube diameter. All of the buckling modes are classified into two deformation phases. In the first phase, which corresponds to an elliptic deformation, the radial stiffness increases rapidly with increasing N. In contrast, the second phase yields wavy, corrugated structures along the circumference for which the radial stiffness declines with increasing N. The hard-to-soft phase transition in radial buckling is a direct consequence of the core-shell structure of MWNTs. Special attention is devoted to how the variation in d affects the critical tube number Nc, which separates the two deformation phases observed in N -walled nanotubes, i.e., the elliptic phase for N Nc. We demonstrate that a larger d tends to result in a smaller Nc, which is attributed to the primary role of the interatomic forces between concentric tubes in the hard-to-soft transition during the radial buckling of MWNTs.展开更多
Helsmoortel-Van der Aa综合征(HVDAS)是一种罕见的神经发育障碍性疾病,主要由活性依赖性神经保护蛋白(ADNP)基因突变引起,是最常见的孤独症谱系障碍(ASD)单基因病因之一。本文分析2024年就诊于海口市妇幼保健院的1例患儿,男,3岁10个月...Helsmoortel-Van der Aa综合征(HVDAS)是一种罕见的神经发育障碍性疾病,主要由活性依赖性神经保护蛋白(ADNP)基因突变引起,是最常见的孤独症谱系障碍(ASD)单基因病因之一。本文分析2024年就诊于海口市妇幼保健院的1例患儿,男,3岁10个月,因“运动、语言发育迟缓2年余,社交障碍1年余”入院,检查发现患儿存在孤独症谱系障碍、全面发育迟缓、特殊面容、矮小、脑积水等临床表现,基因检测发现患儿携带ADNP基因杂合突变{NM_001282531.3(ADNP):c.2189(exon6)delG[p.(Arg730Glnfs3)]},其父母及妹妹均未携带该突变。总结临床资料并结合文献复习,ADNP基因在染色质重塑和神经发育障碍中发挥重要作用,ADNP基因突变可累及多系统。此例HVDAS具有典型临床表现,并拓宽了脑积水的表型谱,为此类基因变异的遗传咨询以及临床医师的早期识别提供了参考依据。展开更多
虚拟电厂(virtual power plant,VPP)通过先进的控制技术高效聚合容量小、数量多的分布式能源(distributed energy resource,DER)参与电力市场交易。随着DER数量的增加,其出力的波动性以及聚合后的收益问题需要解决。基于此,提出一种在...虚拟电厂(virtual power plant,VPP)通过先进的控制技术高效聚合容量小、数量多的分布式能源(distributed energy resource,DER)参与电力市场交易。随着DER数量的增加,其出力的波动性以及聚合后的收益问题需要解决。基于此,提出一种在日前电力市场下,多类型DER聚合于VPP的协同博弈调度模型。首先,提出多类型DER聚合于VPP的运营框架。其次,由于风光出力的不确定性严重影响系统的运行,建立基于变分模态分解(variational modal decomposition,VMD)和改进的双向多门控长短期记忆(bidirectional multi gated long short-term memory,Bi-MGLSTM)网络的组合预测模型。然后,同类型DER形成联盟,并以售电收益最大化为目标,构建VPP多联盟的合作博弈调度模型,为实现联盟及成员间收益分配的公平性,设计多因素改进shapley值法和基于奇偶循环核仁法的两阶段细化收益分配方案。最后,算例结果表明,所提方法能有效提高风光功率的预测精度,实现VPP内联盟间合作互补运行,保证了多个主体间收益分配的公平性与合理性。展开更多
Helsmoortel-Van der Aa综合征(HVDAS),是一种罕见的神经发育障碍疾病,主要由功能活性依赖神经保护蛋白(ADNP)基因突变引起。该文回顾性分析了就诊于济宁医学院附属医院的1例HVDAS患儿,系1岁3个月男性幼儿,其存在运动、语言、智力发育...Helsmoortel-Van der Aa综合征(HVDAS),是一种罕见的神经发育障碍疾病,主要由功能活性依赖神经保护蛋白(ADNP)基因突变引起。该文回顾性分析了就诊于济宁医学院附属医院的1例HVDAS患儿,系1岁3个月男性幼儿,其存在运动、语言、智力发育障碍及孤独症样刻板行为,有行为问题,外貌畸形,视力异常,反复呼吸道感染等临床表现,基因检测发现患儿携带ADNP基因杂合突变c.2157C>A(p.Tyr719Ter),其父母均未携带该突变。因此,提示临床工作者要加强对该疾病的认识,做到早发现、早治疗,以积极干预,从而提高患儿的生活质量。展开更多
本文报道1例ADNP基因新发杂合变异Helsmoortel-Van der Aa综合征病例。该患儿为1岁6月男童,存在有特殊面容、智力发育低下、运动、语言发育迟缓、小手等临床表现,基因分析显示患儿ADNP基因有一个新发变异位点C.460_461insAA(p.P154Qfs*...本文报道1例ADNP基因新发杂合变异Helsmoortel-Van der Aa综合征病例。该患儿为1岁6月男童,存在有特殊面容、智力发育低下、运动、语言发育迟缓、小手等临床表现,基因分析显示患儿ADNP基因有一个新发变异位点C.460_461insAA(p.P154Qfs*7),为移码突变。Helsmoortel-Van der Aa综合征可累及多系统,基因检测有助于诊断。展开更多
We aim to systematically review challenges imposed by emerging distributed energy resources(DERs)to model in two basic distribution management system(DMS)online applications—power flow and short-circuit analysis,as w...We aim to systematically review challenges imposed by emerging distributed energy resources(DERs)to model in two basic distribution management system(DMS)online applications—power flow and short-circuit analysis,as well as to offer a systematic review of potential solutions.In the last decade,electronically coupled DERs became increasingly popular.DERs can employ a wide range of control strategies for power,current,or voltage control,in both normal and faulted conditions.Therefore,DERs cannot be modeled with the traditional PQ(load or generator bus)or PV(generator bus)bus types used for modeling synchronous and induction machines in online power flow calculations.Moreover,since fault currents of DERs are limited to predefined maximal values,electronically coupled DERs cannot be represented with traditional voltage source behind impedance models for online short-circuit calculation(SCC).However,most of the DMS software packages still use the traditional models to represent all DER types,including those that are electronically coupled.This paper shows that there will be large calculation errors in such practice,which make the system model an inadequate representation of the system.This will lead to serious errors in the management,control,and operation of distribution systems.Nonetheless,potential solutions to the challenges are systematically reviewed.Finally,the calculation results on a distribution test system with all DER types are used to prove the claim.展开更多
为深入了解Bonhoeffer-van der Pol系统在随机激励下系统动力学行为的演化规律,研究了随机Bonhoeffer-van der Pol系统的稳态响应和随机分岔。借助路径积分方法、高斯闭合方法和蒙特卡洛模拟等,求解了噪声激励下Bonhoeffer-van der Pol...为深入了解Bonhoeffer-van der Pol系统在随机激励下系统动力学行为的演化规律,研究了随机Bonhoeffer-van der Pol系统的稳态响应和随机分岔。借助路径积分方法、高斯闭合方法和蒙特卡洛模拟等,求解了噪声激励下Bonhoeffer-van der Pol系统的平稳解,发现系统参数诱导的随机P-分岔(唯像分岔)现象。通过与蒙特卡洛模拟结果的对比,验证了所述路径积分方法的准确性。展开更多
Rapid industrialization advancements have grabbed worldwide attention to integrate a very large number of electronic components into a smaller space for performing multifunctional operations.To fulfill the growing com...Rapid industrialization advancements have grabbed worldwide attention to integrate a very large number of electronic components into a smaller space for performing multifunctional operations.To fulfill the growing computing demand state-of-the-art materials are required for substituting traditional silicon and metal oxide semiconductors frameworks.Two-dimensional(2D)materials have shown their tremendous potential surpassing the limitations of conventional materials for developing smart devices.Despite their ground-breaking progress over the last two decades,systematic studies providing in-depth insights into the exciting physics of 2D materials are still lacking.Therefore,in this review,we discuss the importance of 2D materials in bridging the gap between conventional and advanced technologies due to their distinct statistical and quantum physics.Moreover,the inherent properties of these materials could easily be tailored to meet the specific requirements of smart devices.Hence,we discuss the physics of various 2D materials enabling them to fabricate smart devices.We also shed light on promising opportunities in developing smart devices and identified the formidable challenges that need to be addressed.展开更多
van der Waals(vdW)heterostructures constructed by lowdimensional(0D,1D,and 2D)materials are emerging as one of the most appealing systems in next-generation flexible photodetection.Currently,hand-stacked vdW-type phot...van der Waals(vdW)heterostructures constructed by lowdimensional(0D,1D,and 2D)materials are emerging as one of the most appealing systems in next-generation flexible photodetection.Currently,hand-stacked vdW-type photodetectors are not compatible with large-areaarray fabrication and show unimpressive performance in self-powered mode.Herein,vertical 1D GaN nanorods arrays(NRAs)/2D MoS_(2)/PEDOT:PSS in wafer scale have been proposed for self-powered flexible photodetectors arrays firstly.The as-integrated device without external bias under weak UV illumination exhibits a competitive responsivity of 1.47 A W^(−1)and a high detectivity of 1.2×10^(11)Jones,as well as a fast response speed of 54/71μs,thanks to the strong light absorption of GaN NRAs and the efficient photogenerated carrier separation in type-II heterojunction.Notably,the strain-tunable photodetection performances of device have been demonstrated.Impressively,the device at−0.78%strain and zero bias reveals a significantly enhanced photoresponse with a responsivity of 2.47 A W^(−1),a detectivity of 2.6×10^(11)Jones,and response times of 40/45μs,which are superior to the state-of-the-art self-powered flexible photodetectors.This work presents a valuable avenue to prepare tunable vdWs heterostructures for self-powered flexible photodetection,which performs well in flexible sensors.展开更多
As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories(TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However,TCAM c...As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories(TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However,TCAM cells based on conventional silicon-based devices suffer from structural complexity and large footprintlimitations. Here, we demonstrate an ultrafast nonvolatile TCAM cell based on the MoTe2/hBN/multilayergraphene (MLG) van der Waals heterostructure using a top-gated partial floating-gate field-effect transistor(PFGFET) architecture. Based on its ambipolar transport properties, the carrier type in the source/drain andcentral channel regions of the MoTe2 channel can be efficiently tuned by the control gate and top gate, respectively,enabling the reconfigurable operation of the device in either memory or FET mode. When working inthe memory mode, it achieves an ultrafast 60 ns programming/erase speed with a current on-off ratio of ∼105,excellent retention capability, and robust endurance. When serving as a reconfigurable transistor, unipolar p-typeand n-type FETs are obtained by adopting ultrafast 60 ns control-gate voltage pulses with different polarities.The monolithic integration of memory and logic within a single device enables the content-addressable memory(CAM) functionality. Finally, by integrating two PFGFETs in parallel, a TCAM cell with a high current ratioof ∼10^(5) between the match and mismatch states is achieved without requiring additional peripheral circuitry.These results provide a promising route for the design of high-performance TCAM devices for future in-memorycomputing applications.展开更多
基金financial support from the Australian Research Council in grants DP180101744 and DP180101955support from the US National Science Foundation under Grant DMR-1923929。
文摘Near-equiatomic NiTi shape memory alloys are known to exhibit Lüders-type deformation associated with a stress-induced transformation.Many studies have been conducted in the past mainly focusing on the macroscopic characteristics of the phenomenon and some theories have been proposed in the literature to explain its mechanisms,but some aspects of this phenomenon are still unclear,particularly at the microscopic scale.This study investigated the local strain evolution during the initiation and propagation of Lüders band in a pseudoelastic NiTi alloy during tensile deformation by means of digital image correlation(DIC)analysis.Based on the evidence collected,distinct stages of Lüders band formation and propagation are defined and the corresponding local strain rates are obtained.These local strain rates are much higher than the global strain rate of the testing,giving insight to the mechanism of this phenomenon.
基金financially supported by the BAJC(Baosteel-Australia Joint Research and Development Centre)Project。
文摘In this study,the high-strength pipe steel,i.e.X80,was heated at 260℃for half an hour followed by air cooling for thermal simulation of pipe coating process.During the uniaxial loading of the specified tension samples,the migration behaviour of Lüders bands and the re-distribution of stress after strain ageing heat treatment were investigated using digital image correlation.Digital image correlation was adopted to characterise the local axial and shear strain fields of samples that were extracted from different locations across the wall thickness of the high-strength pipe steel,and electron backscatter diffraction was used to compare the evolution of crystallographic texture among these locations.Other characterisation methods regarding microstructure and mechanical properties were conducted meanwhile,including optical microscopy,scanning electron microscopy and X-ray diffraction to accurately define the detailed performances that strain ageing,i.e.being heated to 260℃for half an hour,has led to.The obtained results show that the Lüders band-related microstructure,dislocation density,lattice constant and texture vary at the different locations across the wall thickness and influence the fi nal mechanical properties of the selected high-strength pipe steel.
文摘Editor's note: We are sorry that because of the over-crowded space in our last issue, we are delayed in presenting the second part of the report delivered by the CAS President Lu Yongxiang at the 2002 working conference of CAS. The report appears in two installments in this and the 1st issue of this volume.
文摘Addition of Fe B C and Fe Mo B C m aster alloy pow ders to Fe Mo B Csintered steels can ac tivate the sintering process by liquid phase sintering . The for m ation of liquid ( α- Fe + ( Fe , Mo) 2 B+ Fe3( B, C) → L) i m proves m echanical properties of the steels , and ultim ate tensilestrengths of 684 774 M Pa , i m pact energy of 47 ±7 Jand elongation of 2 5 ±0 9 were ob tained . Optim u m a mount of liquid phase exists , and alarge a mount of liquid phase will re sult in the form ation of continuous netw ork of liquid phase that is detrim ental to strength andelongation .
文摘Synthesis of a m m oniu m alu min u m carbonate hydroxide ( A A C H) w as investigated usinga m m oniu m alu min u m sulfate and a m moniu m hydro carbonate as the starting m aterials . Itw as found that A A C Hcan be synthesized by adding a m m oniu m alu m inu m sulfate solution torapidly stirred a m moniu m hydro - carbonate solution at a tem perature of 30 ℃. A A C Hcantransfor m to α Al2 O3 co m pletely by calcining at 1100 ℃ for 1 hour , and the obtained po w ders , with a particle size of 100 n m , can be sintered to 98 99 % relative density at 1500 ℃for 2 hours .
文摘We investigate the cross-sectional buckling of multi-concentric tubular nanomaterials, which are called multiwalled carbon nanotubes (MWNTs), using an analysis based on thin-shell theory. MWNTs under hydrostatic pressure experience radial buckling. As a result of this, different buckling modes are obtained depending on the inter-tube separation d as well as the number of constituent tubes N and the innermost tube diameter. All of the buckling modes are classified into two deformation phases. In the first phase, which corresponds to an elliptic deformation, the radial stiffness increases rapidly with increasing N. In contrast, the second phase yields wavy, corrugated structures along the circumference for which the radial stiffness declines with increasing N. The hard-to-soft phase transition in radial buckling is a direct consequence of the core-shell structure of MWNTs. Special attention is devoted to how the variation in d affects the critical tube number Nc, which separates the two deformation phases observed in N -walled nanotubes, i.e., the elliptic phase for N Nc. We demonstrate that a larger d tends to result in a smaller Nc, which is attributed to the primary role of the interatomic forces between concentric tubes in the hard-to-soft transition during the radial buckling of MWNTs.
文摘Helsmoortel-Van der Aa综合征(HVDAS)是一种罕见的神经发育障碍性疾病,主要由活性依赖性神经保护蛋白(ADNP)基因突变引起,是最常见的孤独症谱系障碍(ASD)单基因病因之一。本文分析2024年就诊于海口市妇幼保健院的1例患儿,男,3岁10个月,因“运动、语言发育迟缓2年余,社交障碍1年余”入院,检查发现患儿存在孤独症谱系障碍、全面发育迟缓、特殊面容、矮小、脑积水等临床表现,基因检测发现患儿携带ADNP基因杂合突变{NM_001282531.3(ADNP):c.2189(exon6)delG[p.(Arg730Glnfs3)]},其父母及妹妹均未携带该突变。总结临床资料并结合文献复习,ADNP基因在染色质重塑和神经发育障碍中发挥重要作用,ADNP基因突变可累及多系统。此例HVDAS具有典型临床表现,并拓宽了脑积水的表型谱,为此类基因变异的遗传咨询以及临床医师的早期识别提供了参考依据。
文摘虚拟电厂(virtual power plant,VPP)通过先进的控制技术高效聚合容量小、数量多的分布式能源(distributed energy resource,DER)参与电力市场交易。随着DER数量的增加,其出力的波动性以及聚合后的收益问题需要解决。基于此,提出一种在日前电力市场下,多类型DER聚合于VPP的协同博弈调度模型。首先,提出多类型DER聚合于VPP的运营框架。其次,由于风光出力的不确定性严重影响系统的运行,建立基于变分模态分解(variational modal decomposition,VMD)和改进的双向多门控长短期记忆(bidirectional multi gated long short-term memory,Bi-MGLSTM)网络的组合预测模型。然后,同类型DER形成联盟,并以售电收益最大化为目标,构建VPP多联盟的合作博弈调度模型,为实现联盟及成员间收益分配的公平性,设计多因素改进shapley值法和基于奇偶循环核仁法的两阶段细化收益分配方案。最后,算例结果表明,所提方法能有效提高风光功率的预测精度,实现VPP内联盟间合作互补运行,保证了多个主体间收益分配的公平性与合理性。
文摘Helsmoortel-Van der Aa综合征(HVDAS),是一种罕见的神经发育障碍疾病,主要由功能活性依赖神经保护蛋白(ADNP)基因突变引起。该文回顾性分析了就诊于济宁医学院附属医院的1例HVDAS患儿,系1岁3个月男性幼儿,其存在运动、语言、智力发育障碍及孤独症样刻板行为,有行为问题,外貌畸形,视力异常,反复呼吸道感染等临床表现,基因检测发现患儿携带ADNP基因杂合突变c.2157C>A(p.Tyr719Ter),其父母均未携带该突变。因此,提示临床工作者要加强对该疾病的认识,做到早发现、早治疗,以积极干预,从而提高患儿的生活质量。
文摘本文报道1例ADNP基因新发杂合变异Helsmoortel-Van der Aa综合征病例。该患儿为1岁6月男童,存在有特殊面容、智力发育低下、运动、语言发育迟缓、小手等临床表现,基因分析显示患儿ADNP基因有一个新发变异位点C.460_461insAA(p.P154Qfs*7),为移码突变。Helsmoortel-Van der Aa综合征可累及多系统,基因检测有助于诊断。
基金the Ministry of Education and Science of the Republic of Serbia for its support to this research through the ProjectⅢ-42004.
文摘We aim to systematically review challenges imposed by emerging distributed energy resources(DERs)to model in two basic distribution management system(DMS)online applications—power flow and short-circuit analysis,as well as to offer a systematic review of potential solutions.In the last decade,electronically coupled DERs became increasingly popular.DERs can employ a wide range of control strategies for power,current,or voltage control,in both normal and faulted conditions.Therefore,DERs cannot be modeled with the traditional PQ(load or generator bus)or PV(generator bus)bus types used for modeling synchronous and induction machines in online power flow calculations.Moreover,since fault currents of DERs are limited to predefined maximal values,electronically coupled DERs cannot be represented with traditional voltage source behind impedance models for online short-circuit calculation(SCC).However,most of the DMS software packages still use the traditional models to represent all DER types,including those that are electronically coupled.This paper shows that there will be large calculation errors in such practice,which make the system model an inadequate representation of the system.This will lead to serious errors in the management,control,and operation of distribution systems.Nonetheless,potential solutions to the challenges are systematically reviewed.Finally,the calculation results on a distribution test system with all DER types are used to prove the claim.
文摘为深入了解Bonhoeffer-van der Pol系统在随机激励下系统动力学行为的演化规律,研究了随机Bonhoeffer-van der Pol系统的稳态响应和随机分岔。借助路径积分方法、高斯闭合方法和蒙特卡洛模拟等,求解了噪声激励下Bonhoeffer-van der Pol系统的平稳解,发现系统参数诱导的随机P-分岔(唯像分岔)现象。通过与蒙特卡洛模拟结果的对比,验证了所述路径积分方法的准确性。
文摘Rapid industrialization advancements have grabbed worldwide attention to integrate a very large number of electronic components into a smaller space for performing multifunctional operations.To fulfill the growing computing demand state-of-the-art materials are required for substituting traditional silicon and metal oxide semiconductors frameworks.Two-dimensional(2D)materials have shown their tremendous potential surpassing the limitations of conventional materials for developing smart devices.Despite their ground-breaking progress over the last two decades,systematic studies providing in-depth insights into the exciting physics of 2D materials are still lacking.Therefore,in this review,we discuss the importance of 2D materials in bridging the gap between conventional and advanced technologies due to their distinct statistical and quantum physics.Moreover,the inherent properties of these materials could easily be tailored to meet the specific requirements of smart devices.Hence,we discuss the physics of various 2D materials enabling them to fabricate smart devices.We also shed light on promising opportunities in developing smart devices and identified the formidable challenges that need to be addressed.
基金supported by the National Key Research and Development Program of China(No.2022YFB3604500,No.2022YFB3604501)the National Natural Science Foundation of China(No.52172141)the Technology Development Project of Shanxi-Zheda Institude of Advanced Materials and Chemical Engineering(No.2022SX-TD017).
文摘van der Waals(vdW)heterostructures constructed by lowdimensional(0D,1D,and 2D)materials are emerging as one of the most appealing systems in next-generation flexible photodetection.Currently,hand-stacked vdW-type photodetectors are not compatible with large-areaarray fabrication and show unimpressive performance in self-powered mode.Herein,vertical 1D GaN nanorods arrays(NRAs)/2D MoS_(2)/PEDOT:PSS in wafer scale have been proposed for self-powered flexible photodetectors arrays firstly.The as-integrated device without external bias under weak UV illumination exhibits a competitive responsivity of 1.47 A W^(−1)and a high detectivity of 1.2×10^(11)Jones,as well as a fast response speed of 54/71μs,thanks to the strong light absorption of GaN NRAs and the efficient photogenerated carrier separation in type-II heterojunction.Notably,the strain-tunable photodetection performances of device have been demonstrated.Impressively,the device at−0.78%strain and zero bias reveals a significantly enhanced photoresponse with a responsivity of 2.47 A W^(−1),a detectivity of 2.6×10^(11)Jones,and response times of 40/45μs,which are superior to the state-of-the-art self-powered flexible photodetectors.This work presents a valuable avenue to prepare tunable vdWs heterostructures for self-powered flexible photodetection,which performs well in flexible sensors.
基金supported by the National Key Research&Development Projects of China(Grant No.2022YFA1204100)National Natural Science Foundation of China(Grant No.62488201)+1 种基金CAS Project for Young Scientists in Basic Research(YSBR-003)the Innovation Program of Quantum Science and Technology(2021ZD0302700)。
文摘As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories(TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However,TCAM cells based on conventional silicon-based devices suffer from structural complexity and large footprintlimitations. Here, we demonstrate an ultrafast nonvolatile TCAM cell based on the MoTe2/hBN/multilayergraphene (MLG) van der Waals heterostructure using a top-gated partial floating-gate field-effect transistor(PFGFET) architecture. Based on its ambipolar transport properties, the carrier type in the source/drain andcentral channel regions of the MoTe2 channel can be efficiently tuned by the control gate and top gate, respectively,enabling the reconfigurable operation of the device in either memory or FET mode. When working inthe memory mode, it achieves an ultrafast 60 ns programming/erase speed with a current on-off ratio of ∼105,excellent retention capability, and robust endurance. When serving as a reconfigurable transistor, unipolar p-typeand n-type FETs are obtained by adopting ultrafast 60 ns control-gate voltage pulses with different polarities.The monolithic integration of memory and logic within a single device enables the content-addressable memory(CAM) functionality. Finally, by integrating two PFGFETs in parallel, a TCAM cell with a high current ratioof ∼10^(5) between the match and mismatch states is achieved without requiring additional peripheral circuitry.These results provide a promising route for the design of high-performance TCAM devices for future in-memorycomputing applications.
