Urban and community forestry is a specialized discipline focused on the meticulous management of trees and forests within urban,suburban,and town environments.This field often entails extensive civic involvement and c...Urban and community forestry is a specialized discipline focused on the meticulous management of trees and forests within urban,suburban,and town environments.This field often entails extensive civic involvement and collaborative partnerships with institutions.Its overarching objectives span a spectrum from preserving water quality,habitat,and biodiversity to mitigating the Urban Heat Island(UHI)effect.The UHI phenomenon,characterized by notably higher temperatures in urban areas compared to rural counterparts due to heat absorption by urban infrastructure and limited urban forest coverage,serves as a focal point in this study.The study focuses on developing a methodological framework that integrates Geographically Weighted Regression(GWR),Random Forest(RF),and Suitability Analysis to assess the Urban Heat Island(UHI)effect across different urban zones,aiming to identify areas with varying levels of UHI impact.The framework is designed to assist urban planners and designers in understanding the spatial distribution of UHI and identifying areas where urban forestry initiatives can be strategically implemented to mitigate its effect.Conducted in various London areas,the research provides a comprehensive analysis of the intricate relationship between urban and community forestry and UHI.By mapping the spatial variability of UHI,the framework offers a novel approach to enhancing urban environmental design and advancing urban forestry studies.The study’s findings are expected to provide valuable insights for urban planners and policymakers,aiding in creating healthier and more livable urban environments through informed decision-making in urban forestry management.展开更多
Photoelectric synaptic devices could emulate synaptic behaviors utilizing photoelectric effects and offer promising prospects with their high-speed operation and low crosstalk. In this study, we introduced a novel InG...Photoelectric synaptic devices could emulate synaptic behaviors utilizing photoelectric effects and offer promising prospects with their high-speed operation and low crosstalk. In this study, we introduced a novel InGaZnO-based photoelectric memristor. Under both electrical and optical stimulation, the device successfully emulated synaptic characteristics including excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), long-term potentiation (LTP), and long-term depression (LTD). Furthermore, we demonstrated the practical application of our synaptic devices through the recognition of handwritten digits. The devices have successfully shown their ability to modulate synaptic weights effectively through light pulse stimulation, resulting in a recognition accuracy of up to 93.4%. The results illustrated the potential of IGZO-based memristors in neuromorphic computing, particularly their ability to simulate synaptic functionalities and contribute to image recognition tasks.展开更多
As an indispensable branch of wearable electronics,flexible pressure sensors are gaining tremendous attention due to their extensive applications in health monitoring,human-machine interaction,artificial intelligence,...As an indispensable branch of wearable electronics,flexible pressure sensors are gaining tremendous attention due to their extensive applications in health monitoring,human-machine interaction,artificial intelligence,the internet of things,and other fields.In recent years,highly flexible and wearable pressure sensors have been developed using various materials/structures and transduction mechanisms.Morphological engineering of sensing materials at the nanometer and micrometer scales is crucial to obtaining superior sensor performance.This review focuses on the rapid development of morphological engineering technologies for flexible pressure sensors.We discuss different architectures and morphological designs of sensing materials to achieve high performance,including high sensitivity,broad working range,stable sensing,low hysteresis,high transparency,and directional or selective sensing.Additionally,the general fabrication techniques are summarized,including self-assembly,patterning,and auxiliary synthesis methods.Furthermore,we present the emerging applications of high-performing microengineered pressure sensors in healthcare,smart homes,digital sports,security monitoring,and machine learning-enabled computational sensing platform.Finally,the potential challenges and prospects for the future developments of pressure sensors are discussed comprehensively.展开更多
Semiconductive two dimensional(2D)materials have attracted significant research attention due to their rich band structures and promising potential for next-generation electrical devices.In this work,we investigate th...Semiconductive two dimensional(2D)materials have attracted significant research attention due to their rich band structures and promising potential for next-generation electrical devices.In this work,we investigate the MoS2 field-effect transistors(FETs)with a dual-gated(DG)architecture,which consists of symmetrical thickness for back gate(BG)and top gate(TG)dielectric.The thickness-dependent charge transport in our DG-MoS2 device is revealed by a four-terminal electrical measurement which excludes the contact influence,and the TCAD simulation is also applied to explain the experimental data.Our results indicate that the impact of quantum confinement effect plays an important role in the charge transport in the MoS2 channel,as it confines charge carriers in the center of the channel,which reduces the scattering and boosts the mobility compared to the single gating case.Furthermore,temperature-dependent transfer curves reveal that multi-layer MoS2 DG-FET is in the phonon-limited transport regime,while single layer MoS2 shows typical Coulomb impurity limited regime.展开更多
We aimed to explore the efficacy and safety of etoposide capsule combined with cisplatin or carboplatin in the treatment of elderly patients with small cell lung cancer (SCLC). Methods: From October 2011 to Novembe...We aimed to explore the efficacy and safety of etoposide capsule combined with cisplatin or carboplatin in the treatment of elderly patients with small cell lung cancer (SCLC). Methods: From October 2011 to November 2013, 32 elderly patients (71-79 years old) with histopathologically confirmed SCLC in General Hospital of Shenyang Military Region (China) were enrolled in the research. The patients were administrated with lastet capsule 150-175 mg, dl-5, combined with cisplatin 20 mg/m^2 dl-3 or carbopiatin AUC = 5, applied over 2 days. Twenty-one days were 1 treatment cycle. Results:After treatments, 2 cases acquired complete response (CR), 19 cases acquired partial response (PR), 8 cases acquired stable disease (SD), and 3 cases had progression of disease (PD). The objective response rate was 65.6% (21/32), disease control rate was 90.6% (29/32). The median time of progression-free survival (PFS) was 6.9 months, the median survival time was 14.0 months, and 1 year survival rate was 62.4%. The main adverse reactions of 1/11 leukopenia and gastrointestinal reaction were observed. Conclusion: Etoposide capsule combined with cisplatin or carboplatin therapy have curative effect and good tolerance in elderly patients with SCLC.展开更多
Traditional computing structures are blocked by the von Neumann bottleneck,and neuromorphic computing devices inspired by the human brain which integrate storage and computation have received more and more attention.H...Traditional computing structures are blocked by the von Neumann bottleneck,and neuromorphic computing devices inspired by the human brain which integrate storage and computation have received more and more attention.Here,a flexible organic device with 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene(C8-BTBT)and 2,9-didecyldinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene(C10-DNTT)heterostructural channel having excellent synaptic behaviors was fabricated on muscovite(MICA)substrate,which has a memory window greater than 20 V.This device shows better electrical characteristics than organic field effect transistors with single organic semiconductor channel.Furthermore,the device simulates organism synaptic behaviors successfully,such as paired-pulse facilitation(PPF),long-term potentiation/depression(LTP/LTD)process,and transition from short-term memory(STM)to long-term memory(LTM)by optical and electrical modulations.Importantly,the neuromorphic computing function was verified using the Modified National Institute of Standards and Technology(MNIST)pattern recognition,with a recognition rate nearly 100%without noise.This research proposes a flexible organic heterojunction with the ultra-high recognition rate in MNIST pattern recognition and provides the possibility for future flexible wearable neuromorphic computing devices.展开更多
Ultralow concentration molecular detection is critical in various fields,e.g.,food safety,environmental monitoring,and dis-ease diagnosis.Highly sensitive surface-enhanced Raman scattering(SERS)based on ultra-wettable...Ultralow concentration molecular detection is critical in various fields,e.g.,food safety,environmental monitoring,and dis-ease diagnosis.Highly sensitive surface-enhanced Raman scattering(SERS)based on ultra-wettable surfaces has attracted attention due to its unique ability to detect trace molecules.However,the complexity and cost associated with the preparation of traditional SERS substrates restrict their practical application.Thus,an efficient SERS substrate preparation with high sensitivity,a simplified process,and controllable cost is required.In this study,a superhydrophobic–hydrophilic patterned Cu@Ag composite SERS substrate was fabricated using femtosecond laser processing technology combined with silver plating and surface modification treatment.By inducing periodic stripe structures through femtosecond laser processing,the developed substrate achieves uniform distribution hotspots.Using the surface wettability difference,the object to be measured can be confined in the hydrophilic region and the edge of the hydrophilic region,where the analyte is enriched by the coffee ring effect,can be quickly located by surface morphology difference of micro-nanostructures;thus,greatly improving detec-tion efficiency.The fabricated SERS substrate can detect Rhodamine 6G(R6G)at an extraordinarily low concentration of 10^(−15)mol/L,corresponding to an enhancement factor of 1.53×10^(8).This substrate has an ultralow detection limit,incurs low processing costs and is simple to prepare;thus,the substrate has significant application potential in the trace analysis field.展开更多
As a type of three-terminal transistor,organic electrochemical transistors(OECTs)can effectively modulate their channel conductivity through ionic electrochemical doping across gate-electrolyte-channel routes,endowing...As a type of three-terminal transistor,organic electrochemical transistors(OECTs)can effectively modulate their channel conductivity through ionic electrochemical doping across gate-electrolyte-channel routes,endowing their versatile applications in bioelectronics,low power logic circuit,and neuromorphic computing[1].In the concrete,free cations/anions in aqueous electrolytes driven by gate voltage can effectively penetrate into the bulk channel,then resulting in the volumetric n/p-doping of channel semiconductors.Notably,the film thickness of the channel also involves the modulation of OECT performance owing to the polymer swelling and ion penetration,which is hardly occurred in other transistors working in field-effect mode.展开更多
The explosively developed era of big-data compels the increasing demand of nonvolatile memory with high efficiency and excellent storage properties.Herein,we fabricated a high-speed photoelectric multilevel memory dev...The explosively developed era of big-data compels the increasing demand of nonvolatile memory with high efficiency and excellent storage properties.Herein,we fabricated a high-speed photoelectric multilevel memory device for neuromorphic computing.The novel two-dimensional(2D)MoSSe with a unique Janus structure was employed as the channel,and the stack of Al_(2)O_(3)/black phosphorus quantum dots(BPQDs)/Al_(2)O_(3)was adopted as the dielectric.The storage performance of the resulting memory could be verified by the endurance and retention tests,in which the device could remain stable states of programming and erasing even after 1,000 cycles and 1,000 s.The multibit storage could be realized through both different voltage amplitudes and pulse numbers,which could achieve 6 bits(64 distinguishable levels)under pulse width of 50 ns.Furthermore,our memory device also could realize the simulations of synapses in human brain with optical and electric modulations synergistically,such as excitatory post-synaptic current(EPSC),long-term potentiation/depression(LTP/LTD),and spike-timing-dependent plasticity(STDP).Neuromorphic computing was successfully achieved through a high recognition of handwritten digits up to 92.5%after 103 epochs.This research is a promising avenue for the future development of efficient memory and artificial neural network systems.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)such as molybdenum disulfide(M0S2)have been intensively investigated because of their exclusive physical properties for advaneed electronics and optoelectronics...Two-dimensional(2D)transition metal dichalcogenides(TMDs)such as molybdenum disulfide(M0S2)have been intensively investigated because of their exclusive physical properties for advaneed electronics and optoelectronics.In the present work,we study the M0S2 transistor based on a novel tri-gate device architecture,with dual-gate(Dual-G)in the channel and the buried side-gate(Side-G)for the source/drain regi ons.All gates can be in depe ndently con trolled without in terfere nee.For a MoS2 sheet with a thick ness of 3.6 nm,the Schottky barrier(SB)and non-overlapped channel region can be effectively tuned by electrostatically doping the source/drain regions with Side-G.Thus,the extri nsic resista nee can be effectively lowered,and a boost of the ON-state cur re nt can be achieved.Mean while,the cha nn el c ontrol remai ns efficient under the Dual-G mode,with an ON-OFF current ratio of 3 x 107 and subthreshold swing of 83 mV/decade.The corresponding band diagram is also discussed to illustrate the device operati on mechanism.This no vel device structure ope ns up a new way toward fabricati on of high-performance devices based on 2D-TMDs.展开更多
Wafer-scale synthesis of p-type TMD films is critical for its commercialization in next-generation electro/optoelectronics.In this work,wafer-scale intrinsic n-type WS_(2)films and in situ Nb-doped p-type WS_(2)films ...Wafer-scale synthesis of p-type TMD films is critical for its commercialization in next-generation electro/optoelectronics.In this work,wafer-scale intrinsic n-type WS_(2)films and in situ Nb-doped p-type WS_(2)films were synthesized through atomic layer deposition(ALD)on 8-inchα-Al_(2)O_(3)/Si wafers,2-inch sapphire,and 1 cm^(2)GaN substrate pieces.The Nb doping concentration was precisely controlled by altering cycle number of Nb precursor and activated by postannealing.WS_(2)n-FETs and Nb-doped p-FETs with different Nb concentrations have been fabricated using CMOS-compatible processes.X-ray photoelectron spectroscopy,Raman spectroscopy,and Hall measurements confirmed the effective substitutional doping with Nb.The on/off ratio and electron mobility of WS_(2)n-FET are as high as 105 and 6.85 cm^(2)V^(-1)s^(-1),respectively.In WS_(2)p-FET with 15-cycle Nb doping,the on/off ratio and hole mobility are 10 and 0.016 cm^(2)V^(-1)s^(-1),respectively.The p-n structure based on n-and p-type WS_(2)films was proved with a 10^(4)rectifying ratio.The realization of controllable in situ Nb-doped WS_(2)films paved a way for fabricating wafer-scale complementary WS_(2)FETs.展开更多
Streptomyces produces many valuable and important biomolecules with clinical and pharmaceutical applications.The development of simple and highly efficient gene editing tools for genetic modification of Streptomyces i...Streptomyces produces many valuable and important biomolecules with clinical and pharmaceutical applications.The development of simple and highly efficient gene editing tools for genetic modification of Streptomyces is highly desirable.In this study,we developed a screening system for targeted gene knockout using a uracil auxotrophic host(ΔpyrF)resistant to the highly toxic uracil analog of 5-fluoroorotic acid(5-FOA)converted by PyrF,and a non-replicative vector pKC1132-pyrF carrying the complemented pyrF gene coding for orotidine-5'-phosphate decarboxylase.The pyrF gene acts as a positive selection and counterselection marker for recombinants during genetic modifications.Single-crossover homologous integration mutants were selected on minimal medium without uracil by reintroducing pyrF along with pKC1132-pyrF into the genome of the mutantΔpyrF at the targeted locus.Double-crossover recombinants were generated,from which the pyrF gene,plasmid backbone,and targeted gene were excised through homologous recombination exchange.These recombinants were rapidly screened by the counterselection agent,5-FOA.We demonstrated the feasibility and advantage of using this pyrF-based screening system through deleting the otcR gene,which encodes the cluster-situated regulator that directly activates oxytetracycline biosynthesis in Streptomyces rimosus M4018.This system provides a new genetic tool for investigating the genetic characteristics of Streptomyces species.展开更多
A spin-coating method was applied to obtain thinner and smoother poly(ethylene oxide) (PEO)/LiC104 polymer electrolyte films (EFs) with a lower level of crystallization than those obtained using a drop-casting m...A spin-coating method was applied to obtain thinner and smoother poly(ethylene oxide) (PEO)/LiC104 polymer electrolyte films (EFs) with a lower level of crystallization than those obtained using a drop-casting method. When the applied frequency was as high as 10 kHz, the specific capacitance of such EFs with thicknesses of 1.5 μm was on the order of I μF·cm^-2 a value larger than most of the previously reported results achieved from the same material. We then combined the thin EFs with two-dimensional (2D) materials to fabricate a MoS2 transistor with a top gate right above the channel, defined by a shadowmask method, and an inverter device. This transistor showed excellent static characteristics and the inverter device showed excellent switching performance at 100 Hz, which indicates a fast polarization response of the thin EFs. Such device architecture is suitable for future low power and flexible electronics based on 2D materials.展开更多
In recent years,false information or misinformation,which may result from misperception or deception[1,2],has been spread explosively through various social media,such as short videos,Weibo,and lives.In reality,it gen...In recent years,false information or misinformation,which may result from misperception or deception[1,2],has been spread explosively through various social media,such as short videos,Weibo,and lives.In reality,it generates rumors,influences social opinion,and disturbs the social order.The widespread false information on the Internet or public media brings us profound negative effects,especially in the economy,psychology,and daily life.展开更多
Wafer-scale synthesis of p-type TMD films is critical for its commercialization in next-generation electro/optoelectronics.In this work,wafer-scale intrinsic n-type WS_(2)films and in situ Nb-doped p-type WS_(2)films ...Wafer-scale synthesis of p-type TMD films is critical for its commercialization in next-generation electro/optoelectronics.In this work,wafer-scale intrinsic n-type WS_(2)films and in situ Nb-doped p-type WS_(2)films were synthesized through atomic layer deposition(ALD)on 8-inchα-Al_(2)O_(3)/Si wafers,2-inch sapphire,and 1 cm^(2)GaN substrate pieces.The Nb doping concentration was precisely controlled by altering cycle number of Nb precursor and activated by postannealing.WS_(2)n-FETs and Nb-doped p-FETs with different Nb concentrations have been fabricated using CMOS-compatible processes.X-ray photoelectron spectroscopy,Raman spectroscopy,and Hall measurements confirmed the effective substitutional doping with Nb.The on/off ratio and electron mobility of WS_(2)n-FET are as high as 105 and 6.85 cm^(2)V^(-1)s^(-1),respectively.In WS_(2)p-FET with 15-cycle Nb doping,the on/off ratio and hole mobility are 10 and 0.016 cm^(2)V^(-1)s^(-1),respectively.The p-n structure based on n-and p-type WS_(2)films was proved with a 10^(4) rectifying ratio.The realization of controllable in situ Nb-doped WS_(2)films paved a way for fabricating wafer-scale complementary WS_(2)FETs.展开更多
文摘Urban and community forestry is a specialized discipline focused on the meticulous management of trees and forests within urban,suburban,and town environments.This field often entails extensive civic involvement and collaborative partnerships with institutions.Its overarching objectives span a spectrum from preserving water quality,habitat,and biodiversity to mitigating the Urban Heat Island(UHI)effect.The UHI phenomenon,characterized by notably higher temperatures in urban areas compared to rural counterparts due to heat absorption by urban infrastructure and limited urban forest coverage,serves as a focal point in this study.The study focuses on developing a methodological framework that integrates Geographically Weighted Regression(GWR),Random Forest(RF),and Suitability Analysis to assess the Urban Heat Island(UHI)effect across different urban zones,aiming to identify areas with varying levels of UHI impact.The framework is designed to assist urban planners and designers in understanding the spatial distribution of UHI and identifying areas where urban forestry initiatives can be strategically implemented to mitigate its effect.Conducted in various London areas,the research provides a comprehensive analysis of the intricate relationship between urban and community forestry and UHI.By mapping the spatial variability of UHI,the framework offers a novel approach to enhancing urban environmental design and advancing urban forestry studies.The study’s findings are expected to provide valuable insights for urban planners and policymakers,aiding in creating healthier and more livable urban environments through informed decision-making in urban forestry management.
基金supported by the National Key Research and Development Program of China (2021YFA1202600)the NSFC (92064009, 22175042)+3 种基金the Science and Technology Commission of Shanghai Municipality (22501100900)the China Postdoctoral Science Foundation (2022TQ0068, 2023M740644)the Shanghai Sailing Program (23YF1402200, 23YF1402400)the Qilu Young Scholar Program of Shandong University。
文摘Photoelectric synaptic devices could emulate synaptic behaviors utilizing photoelectric effects and offer promising prospects with their high-speed operation and low crosstalk. In this study, we introduced a novel InGaZnO-based photoelectric memristor. Under both electrical and optical stimulation, the device successfully emulated synaptic characteristics including excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), long-term potentiation (LTP), and long-term depression (LTD). Furthermore, we demonstrated the practical application of our synaptic devices through the recognition of handwritten digits. The devices have successfully shown their ability to modulate synaptic weights effectively through light pulse stimulation, resulting in a recognition accuracy of up to 93.4%. The results illustrated the potential of IGZO-based memristors in neuromorphic computing, particularly their ability to simulate synaptic functionalities and contribute to image recognition tasks.
基金supported by the National Natural Science Foundation of China(52003253 and 52103308)the China Postdoctoral Science Foundation(2020M672283).
文摘As an indispensable branch of wearable electronics,flexible pressure sensors are gaining tremendous attention due to their extensive applications in health monitoring,human-machine interaction,artificial intelligence,the internet of things,and other fields.In recent years,highly flexible and wearable pressure sensors have been developed using various materials/structures and transduction mechanisms.Morphological engineering of sensing materials at the nanometer and micrometer scales is crucial to obtaining superior sensor performance.This review focuses on the rapid development of morphological engineering technologies for flexible pressure sensors.We discuss different architectures and morphological designs of sensing materials to achieve high performance,including high sensitivity,broad working range,stable sensing,low hysteresis,high transparency,and directional or selective sensing.Additionally,the general fabrication techniques are summarized,including self-assembly,patterning,and auxiliary synthesis methods.Furthermore,we present the emerging applications of high-performing microengineered pressure sensors in healthcare,smart homes,digital sports,security monitoring,and machine learning-enabled computational sensing platform.Finally,the potential challenges and prospects for the future developments of pressure sensors are discussed comprehensively.
基金supported by the National Key Research and Development Program of China(2016YFA0203900,2018YFA0306101)the National Natural Science Foundation of China(Grant No.91964202)Shanghai Municipal Science and Technology Commission(18JC1410300)。
文摘Semiconductive two dimensional(2D)materials have attracted significant research attention due to their rich band structures and promising potential for next-generation electrical devices.In this work,we investigate the MoS2 field-effect transistors(FETs)with a dual-gated(DG)architecture,which consists of symmetrical thickness for back gate(BG)and top gate(TG)dielectric.The thickness-dependent charge transport in our DG-MoS2 device is revealed by a four-terminal electrical measurement which excludes the contact influence,and the TCAD simulation is also applied to explain the experimental data.Our results indicate that the impact of quantum confinement effect plays an important role in the charge transport in the MoS2 channel,as it confines charge carriers in the center of the channel,which reduces the scattering and boosts the mobility compared to the single gating case.Furthermore,temperature-dependent transfer curves reveal that multi-layer MoS2 DG-FET is in the phonon-limited transport regime,while single layer MoS2 shows typical Coulomb impurity limited regime.
基金Supported by grants from the Sub-Topics of Major Drug Discovery Platform in the Twelfth-Five Year Research Program of China(No.2012ZX09303016-002)China Postdoctoral Science Foundation(No.2012M512119)
文摘We aimed to explore the efficacy and safety of etoposide capsule combined with cisplatin or carboplatin in the treatment of elderly patients with small cell lung cancer (SCLC). Methods: From October 2011 to November 2013, 32 elderly patients (71-79 years old) with histopathologically confirmed SCLC in General Hospital of Shenyang Military Region (China) were enrolled in the research. The patients were administrated with lastet capsule 150-175 mg, dl-5, combined with cisplatin 20 mg/m^2 dl-3 or carbopiatin AUC = 5, applied over 2 days. Twenty-one days were 1 treatment cycle. Results:After treatments, 2 cases acquired complete response (CR), 19 cases acquired partial response (PR), 8 cases acquired stable disease (SD), and 3 cases had progression of disease (PD). The objective response rate was 65.6% (21/32), disease control rate was 90.6% (29/32). The median time of progression-free survival (PFS) was 6.9 months, the median survival time was 14.0 months, and 1 year survival rate was 62.4%. The main adverse reactions of 1/11 leukopenia and gastrointestinal reaction were observed. Conclusion: Etoposide capsule combined with cisplatin or carboplatin therapy have curative effect and good tolerance in elderly patients with SCLC.
基金the National Key Research and Development Program of China(No.2021YFA1202600)the National Natural Science Foundation of China(Nos.92064009 and 22175042)+3 种基金the Science and Technology Commission of Shanghai Municipality(No.22501100900)the China Postdoctoral Science Foundation(Nos.2022TQ0068 and 2023M740644)the Shanghai Sailing Program(Nos.23YF1402200 and 23YF1402400)Jiashan Fudan Institute.
文摘Traditional computing structures are blocked by the von Neumann bottleneck,and neuromorphic computing devices inspired by the human brain which integrate storage and computation have received more and more attention.Here,a flexible organic device with 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene(C8-BTBT)and 2,9-didecyldinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene(C10-DNTT)heterostructural channel having excellent synaptic behaviors was fabricated on muscovite(MICA)substrate,which has a memory window greater than 20 V.This device shows better electrical characteristics than organic field effect transistors with single organic semiconductor channel.Furthermore,the device simulates organism synaptic behaviors successfully,such as paired-pulse facilitation(PPF),long-term potentiation/depression(LTP/LTD)process,and transition from short-term memory(STM)to long-term memory(LTM)by optical and electrical modulations.Importantly,the neuromorphic computing function was verified using the Modified National Institute of Standards and Technology(MNIST)pattern recognition,with a recognition rate nearly 100%without noise.This research proposes a flexible organic heterojunction with the ultra-high recognition rate in MNIST pattern recognition and provides the possibility for future flexible wearable neuromorphic computing devices.
基金support from National Natural Science Foundation of China(Nos.52035009,51761135106)2020 Mobility Programme of the Sino-German Center for Research Promotion(M-0396)the'111'project by the State Administration Foreign Experts Affairs and the Ministry of Education of China(Grant No.B07014).
文摘Ultralow concentration molecular detection is critical in various fields,e.g.,food safety,environmental monitoring,and dis-ease diagnosis.Highly sensitive surface-enhanced Raman scattering(SERS)based on ultra-wettable surfaces has attracted attention due to its unique ability to detect trace molecules.However,the complexity and cost associated with the preparation of traditional SERS substrates restrict their practical application.Thus,an efficient SERS substrate preparation with high sensitivity,a simplified process,and controllable cost is required.In this study,a superhydrophobic–hydrophilic patterned Cu@Ag composite SERS substrate was fabricated using femtosecond laser processing technology combined with silver plating and surface modification treatment.By inducing periodic stripe structures through femtosecond laser processing,the developed substrate achieves uniform distribution hotspots.Using the surface wettability difference,the object to be measured can be confined in the hydrophilic region and the edge of the hydrophilic region,where the analyte is enriched by the coffee ring effect,can be quickly located by surface morphology difference of micro-nanostructures;thus,greatly improving detec-tion efficiency.The fabricated SERS substrate can detect Rhodamine 6G(R6G)at an extraordinarily low concentration of 10^(−15)mol/L,corresponding to an enhancement factor of 1.53×10^(8).This substrate has an ultralow detection limit,incurs low processing costs and is simple to prepare;thus,the substrate has significant application potential in the trace analysis field.
基金the financial support from the Natural Science Foundation of Henan Province,Grant No.232300421324
文摘As a type of three-terminal transistor,organic electrochemical transistors(OECTs)can effectively modulate their channel conductivity through ionic electrochemical doping across gate-electrolyte-channel routes,endowing their versatile applications in bioelectronics,low power logic circuit,and neuromorphic computing[1].In the concrete,free cations/anions in aqueous electrolytes driven by gate voltage can effectively penetrate into the bulk channel,then resulting in the volumetric n/p-doping of channel semiconductors.Notably,the film thickness of the channel also involves the modulation of OECT performance owing to the polymer swelling and ion penetration,which is hardly occurred in other transistors working in field-effect mode.
基金the National Natural Science Foundation of China(NSFC)(Nos.92064009,61904033,and 62004044)Shanghai Rising-Star Program(No.19QA1400600)+1 种基金the Program of Shanghai Subject Chief Scientist(No.18XD1402800)the Support Plans for the Youth Top-Notch Talents of China,and the National Postdoctoral Program for Innovative Talents(No.BX2021070).
文摘The explosively developed era of big-data compels the increasing demand of nonvolatile memory with high efficiency and excellent storage properties.Herein,we fabricated a high-speed photoelectric multilevel memory device for neuromorphic computing.The novel two-dimensional(2D)MoSSe with a unique Janus structure was employed as the channel,and the stack of Al_(2)O_(3)/black phosphorus quantum dots(BPQDs)/Al_(2)O_(3)was adopted as the dielectric.The storage performance of the resulting memory could be verified by the endurance and retention tests,in which the device could remain stable states of programming and erasing even after 1,000 cycles and 1,000 s.The multibit storage could be realized through both different voltage amplitudes and pulse numbers,which could achieve 6 bits(64 distinguishable levels)under pulse width of 50 ns.Furthermore,our memory device also could realize the simulations of synapses in human brain with optical and electric modulations synergistically,such as excitatory post-synaptic current(EPSC),long-term potentiation/depression(LTP/LTD),and spike-timing-dependent plasticity(STDP).Neuromorphic computing was successfully achieved through a high recognition of handwritten digits up to 92.5%after 103 epochs.This research is a promising avenue for the future development of efficient memory and artificial neural network systems.
基金This work was supported by the National Key Research and Development Program of China(Nos.2016YFA0203900 and 2018YFA0306101)Shanghai Municipal Science and Technology Commission(No.18JC1410300)Natural Science Foundation of China(No.61874154).
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)such as molybdenum disulfide(M0S2)have been intensively investigated because of their exclusive physical properties for advaneed electronics and optoelectronics.In the present work,we study the M0S2 transistor based on a novel tri-gate device architecture,with dual-gate(Dual-G)in the channel and the buried side-gate(Side-G)for the source/drain regi ons.All gates can be in depe ndently con trolled without in terfere nee.For a MoS2 sheet with a thick ness of 3.6 nm,the Schottky barrier(SB)and non-overlapped channel region can be effectively tuned by electrostatically doping the source/drain regions with Side-G.Thus,the extri nsic resista nee can be effectively lowered,and a boost of the ON-state cur re nt can be achieved.Mean while,the cha nn el c ontrol remai ns efficient under the Dual-G mode,with an ON-OFF current ratio of 3 x 107 and subthreshold swing of 83 mV/decade.The corresponding band diagram is also discussed to illustrate the device operati on mechanism.This no vel device structure ope ns up a new way toward fabricati on of high-performance devices based on 2D-TMDs.
基金supported by the NSFC(62004044 and 61904033)by State Key Laboratory of ASIC&System(2021MS004)This research was partially supported by the National Science Foundation through the Center for Dynamics and Control of Materials:an NSF MRSEC under Cooperative Agreement No.DMR-1720595。
文摘Wafer-scale synthesis of p-type TMD films is critical for its commercialization in next-generation electro/optoelectronics.In this work,wafer-scale intrinsic n-type WS_(2)films and in situ Nb-doped p-type WS_(2)films were synthesized through atomic layer deposition(ALD)on 8-inchα-Al_(2)O_(3)/Si wafers,2-inch sapphire,and 1 cm^(2)GaN substrate pieces.The Nb doping concentration was precisely controlled by altering cycle number of Nb precursor and activated by postannealing.WS_(2)n-FETs and Nb-doped p-FETs with different Nb concentrations have been fabricated using CMOS-compatible processes.X-ray photoelectron spectroscopy,Raman spectroscopy,and Hall measurements confirmed the effective substitutional doping with Nb.The on/off ratio and electron mobility of WS_(2)n-FET are as high as 105 and 6.85 cm^(2)V^(-1)s^(-1),respectively.In WS_(2)p-FET with 15-cycle Nb doping,the on/off ratio and hole mobility are 10 and 0.016 cm^(2)V^(-1)s^(-1),respectively.The p-n structure based on n-and p-type WS_(2)films was proved with a 10^(4)rectifying ratio.The realization of controllable in situ Nb-doped WS_(2)films paved a way for fabricating wafer-scale complementary WS_(2)FETs.
基金This work is supported by the Natural Science Foundation of Hebei Province(No.C2019209399)Tangshan Science and Technology Project(No.20130208b)+1 种基金the Science and Technology Program of Hebei(No.18222916)the Research Fund for Top Discipline Construction of North China University of Science and Technology(No.18060720),China.
文摘Streptomyces produces many valuable and important biomolecules with clinical and pharmaceutical applications.The development of simple and highly efficient gene editing tools for genetic modification of Streptomyces is highly desirable.In this study,we developed a screening system for targeted gene knockout using a uracil auxotrophic host(ΔpyrF)resistant to the highly toxic uracil analog of 5-fluoroorotic acid(5-FOA)converted by PyrF,and a non-replicative vector pKC1132-pyrF carrying the complemented pyrF gene coding for orotidine-5'-phosphate decarboxylase.The pyrF gene acts as a positive selection and counterselection marker for recombinants during genetic modifications.Single-crossover homologous integration mutants were selected on minimal medium without uracil by reintroducing pyrF along with pKC1132-pyrF into the genome of the mutantΔpyrF at the targeted locus.Double-crossover recombinants were generated,from which the pyrF gene,plasmid backbone,and targeted gene were excised through homologous recombination exchange.These recombinants were rapidly screened by the counterselection agent,5-FOA.We demonstrated the feasibility and advantage of using this pyrF-based screening system through deleting the otcR gene,which encodes the cluster-situated regulator that directly activates oxytetracycline biosynthesis in Streptomyces rimosus M4018.This system provides a new genetic tool for investigating the genetic characteristics of Streptomyces species.
基金This work was supported by the National Key Research and Development Program (No. 2016YFA0203900) and Natural Science Foundation of Shanghai (No.17ZR1446700). P. Z. would like to acknowledge the National Natural Science Foundation of China (Nos. 61376093 and 61622401).
文摘A spin-coating method was applied to obtain thinner and smoother poly(ethylene oxide) (PEO)/LiC104 polymer electrolyte films (EFs) with a lower level of crystallization than those obtained using a drop-casting method. When the applied frequency was as high as 10 kHz, the specific capacitance of such EFs with thicknesses of 1.5 μm was on the order of I μF·cm^-2 a value larger than most of the previously reported results achieved from the same material. We then combined the thin EFs with two-dimensional (2D) materials to fabricate a MoS2 transistor with a top gate right above the channel, defined by a shadowmask method, and an inverter device. This transistor showed excellent static characteristics and the inverter device showed excellent switching performance at 100 Hz, which indicates a fast polarization response of the thin EFs. Such device architecture is suitable for future low power and flexible electronics based on 2D materials.
基金This work was supported by the National Key Research and Development Program of China(2022YFC3302100).
文摘In recent years,false information or misinformation,which may result from misperception or deception[1,2],has been spread explosively through various social media,such as short videos,Weibo,and lives.In reality,it generates rumors,influences social opinion,and disturbs the social order.The widespread false information on the Internet or public media brings us profound negative effects,especially in the economy,psychology,and daily life.
基金supported by the NSFC(62004044 and 61904033)and by State Key Laboratory of ASIC&System(2021MS004)This research was partially supported by the National Science Foundation through the Center for Dynamics and Control of Materials:an NSF MRSEC under Cooperative Agreement No.DMR-1720595.
文摘Wafer-scale synthesis of p-type TMD films is critical for its commercialization in next-generation electro/optoelectronics.In this work,wafer-scale intrinsic n-type WS_(2)films and in situ Nb-doped p-type WS_(2)films were synthesized through atomic layer deposition(ALD)on 8-inchα-Al_(2)O_(3)/Si wafers,2-inch sapphire,and 1 cm^(2)GaN substrate pieces.The Nb doping concentration was precisely controlled by altering cycle number of Nb precursor and activated by postannealing.WS_(2)n-FETs and Nb-doped p-FETs with different Nb concentrations have been fabricated using CMOS-compatible processes.X-ray photoelectron spectroscopy,Raman spectroscopy,and Hall measurements confirmed the effective substitutional doping with Nb.The on/off ratio and electron mobility of WS_(2)n-FET are as high as 105 and 6.85 cm^(2)V^(-1)s^(-1),respectively.In WS_(2)p-FET with 15-cycle Nb doping,the on/off ratio and hole mobility are 10 and 0.016 cm^(2)V^(-1)s^(-1),respectively.The p-n structure based on n-and p-type WS_(2)films was proved with a 10^(4) rectifying ratio.The realization of controllable in situ Nb-doped WS_(2)films paved a way for fabricating wafer-scale complementary WS_(2)FETs.