Investigating thermal transport mechanisms at the interface between phase change materials(PCMs)and high thermally conductive fillers has become increasingly significant in developing phase change energy storage techn...Investigating thermal transport mechanisms at the interface between phase change materials(PCMs)and high thermally conductive fillers has become increasingly significant in developing phase change energy storage technologies.This study explores the interfacial thermal transport between a representative PCM,erythritol,and various fillers,including crystalline(Si C,Si3N4)and amorphous(Si O2)nanoparticles,using molecular dynamics(MD)simulations.Additionally,time-domain thermoreflectance(TDTR)experiments were performed to quantify the interfacial thermal conductance between erythritol and the three types of fillers,yielding values of 50.1,40.0,and25.6 MW m–2K-1.These results align well with the trends observed in the simulations.Furthermore,the underlying mechanisms of interfacial heat transfer were analyzed by examining the phonon density of states,overlap energy,and interaction energy.This research provides innovative insights into nanoscale interfacial thermal transport in composite PCMs.This could lead to significant advancements in thermal management technologies,particularly in developing more efficient thermal energy storage systems.展开更多
The detection of volatile organic compounds(VOCs)holds significant implications in environmental monitoring and disease diagnosis.Traditional gas detection technologies are constrained by complex operation and high co...The detection of volatile organic compounds(VOCs)holds significant implications in environmental monitoring and disease diagnosis.Traditional gas detection technologies are constrained by complex operation and high cost,thereby failing to satisfy real-time detection demands.Surface-enhanced Raman scattering(SERS)provides a noble approach for trace VOCs detection,as it possesses single-molecule sensitivity,rapid response,and the ability to analyze chemical structures without being affected by water molecules.Researchers have successfully achieved precise identification of trace VOCs through the meticulous design of SERS substrates,demonstrating excellent application potential in practical detection.This review comprehensively summarizes the research progress and application of SERS technology in VOCs detection,covering the structural design of SERS substrates and the transformation of actual gas detection methods.Specifically,three core substrate structures include noble metal nanostructures,porous semiconductor composite nanostructures,and noble metal-semiconductor composite porous nanostructures that combine the advantages of both were delved into deeply.Furthermore,it also provides a detailed account of the technological innovations in VOCs detection based on SERS technology,expanding the application scope of SERS technology.Nevertheless,the SERS technology still faces significant challenges in VOC gas detection,including nonspecific adsorption in complex matrices,insufficient long-term substrate stability,the need to simultaneously identify multiple components in a mixed gas,etc.This review summarizes the current challenges in detail and looks forward to future research directions and development prospects.展开更多
Phase-change memory(PCM),characterized by its reversible transition between crystalline and amorphous phases,has emerged as a promising candidate for neuromorphic memory computing applications.However,conventional PCM...Phase-change memory(PCM),characterized by its reversible transition between crystalline and amorphous phases,has emerged as a promising candidate for neuromorphic memory computing applications.However,conventional PCM devices lack an insufficient RESET/SET voltage ratio,which often leads to incorrect recording of the RESET state and limits computational accuracy.In this work,we report a Ge2Sb2Te5-based PCM device achieving a record-breaking RESET/SET voltage ratio exceeding 10,significantly outperforming previously reported values below 5.This enhancement is enabled by an ultrathin(192 nm)architecture combined with a graded thermal conductivity design,which promotes a higher crystalline fraction,effectively reducing the SET voltage whereas maintaining a high RESET voltage.Furthermore,the nucleation and crystal growth mechanisms are systematically investigated,and the amorphous-crystalline phase transition is experimentally validated to enable rapid and reliable switching.These findings provide a new strategy for designing high-performance PCM devices and pave the way for more precise and efficient neuromorphic computing systems.展开更多
Development and reproduction are key processes in the insect life cycle,and vitellogenesis is a critical event in insect reproduction.Vitellogenin(Vg)is generally recognized as a female-specific,reproductive lipoprote...Development and reproduction are key processes in the insect life cycle,and vitellogenesis is a critical event in insect reproduction.Vitellogenin(Vg)is generally recognized as a female-specific,reproductive lipoprotein unique to oviparous taxa that plays a crucial role in vitellogenesis.However,its specific functions,and the mechanisms underlying its regulation,remain poorly understood.We here demonstrate how 20hydroxyecdysone(20E)regulates Vg transcription via the transcription factor CsE74A and the ribosomal protein Cs40SRPS4 in Chilo suppressalis.Disruption of CsVg in G0 generation C.suppressalis via multiplex CRISPR/Cas9 resulted in decreased yolk deposition,ovarian dysplasia,and delayed oocyte maturation.Dual luciferase and DNA pull-down assays identified the CsVg core promoter(—915 to—811 bp)and its binding ribosomal protein Cs40SRPS4.Functional analysis via RNA interference revealed that Cs40SRPS4 is a ribosomal protein capable of regulating vitellogenesis in C.suppressalis.Furthermore,we correctly predicted that the binding site for CsE74A would be on the CsVg core promoter and confirmed its binding capability.Subsequent experiments further confirmed the interaction between CsE74A and Cs40SRPS4.Notably,the expression of CsE74A,Cs40S4,and CsVg significantly increased after 20E treatment.The results revealed that 20E induced the early response factor CsE74A to bind to the CsVg core promoter,thereby regulating Vg transcription and vitellogenesis in conjunction with Cs40SRPS4.These findings not only provide a foundation for gaining deeper understanding of insect reproductive processes,but could also lead to the development of safer,more economical and sustainable,pest control methods.展开更多
Enabling as the second phase of the Production-Oriented Approach(POA)instruction(Wen,2015),plays a vital role in determining the quality of productive performance of English language learners.To explore how to apply t...Enabling as the second phase of the Production-Oriented Approach(POA)instruction(Wen,2015),plays a vital role in determining the quality of productive performance of English language learners.To explore how to apply theoretical principles of enabling to practice,this paper interprets theoretical principles and reports the practice of the classroom implementation of enabling.The paper proposes a definition for enabling,clarifies the confusion between enabling and scaffolding,and clears up some misunderstandings about enabling.It explains three criteria for effective enabling,namely,alignment,gradualness,and variety,and elaborates on the relations among them.Based on the teaching material of Unit 7 of iEnglish,the paper demonstrates how to design and implement enabling activities under the guidance of these three criteria and evaluates the actual effectiveness of the enabling implemented in the classroom.展开更多
The electromagnetic field coupling between two kinds of noble metal nanoparticles endows high surfaceenhanced Raman scattering(SERS) activity but is accompanied by uneven hot spots.Using two-dimensional semiconductors...The electromagnetic field coupling between two kinds of noble metal nanoparticles endows high surfaceenhanced Raman scattering(SERS) activity but is accompanied by uneven hot spots.Using two-dimensional semiconductors with localized surface plasmon resonance(LSPR) effects instead of one of the noble metal components can effectively improve uniformity.Hence,the Ag nanoparticles(Ag NPs) loaded MoO3-x nanoflowers(Ag/MoO3-x) were engineered to exploit dual-plasmonic coupling and realize the trace detection of aldehyde volatile organic compounds(VOCs) gas.The finite-difference time-domain(FDTD) simulation results proved that there is an obvious electromagnetic field coupling effect between Ag NPs and MoO3-x semiconductors,which can amplify the molecular dipole moment significantly.The chemical enhancement mechanism in the Ag/MoO3-x substrate was clarified by band structure analysis,in which the free electrons accumulated at the bottom of the conduction band of the MoO3-x semiconductor can promote the charge transfer process between Ag/MoO3-x and the 4-aminothiophenol(4-ATP) molecule.Moreover,the electron delocalization of 4-ATP molecule was enhanced after being absorbed on Ag/MoO3-x nanoflowers,facilitating the charge transfer between 4-ATP and Ag/MoO3-x substrate effectively.Importantly,using the 4-ATP molecule as a probe,the trace detection of a variety of aldehyde VOCs gas was realized by Ag/MoO3-x.substrate with a low limit of detection(LOD) of 10 ppb.This work provided a new idea for the design of noble metal-plasmonic semiconductor heterostructure substrates.展开更多
Currently,most trains are equipped with dedicated cameras for capturing pantograph videos.Pantographs are core to the high-speed-railway pantograph-catenary system,and their failure directly affects the normal operati...Currently,most trains are equipped with dedicated cameras for capturing pantograph videos.Pantographs are core to the high-speed-railway pantograph-catenary system,and their failure directly affects the normal operation of high-speed trains.However,given the complex and variable real-world operational conditions of high-speed railways,there is no real-time and robust pantograph fault-detection method capable of handling large volumes of surveillance video.Hence,it is of paramount importance to maintain real-time monitoring and analysis of pantographs.Our study presents a real-time intelligent detection technology for identifying faults in high-speed railway pantographs,utilizing a fusion of self-attention and convolution features.We delved into lightweight multi-scale feature-extraction and fault-detection models based on deep learning to detect pantograph anomalies.Compared with traditional methods,this approach achieves high recall and accuracy in pantograph recognition,accurately pinpointing issues like discharge sparks,pantograph horns,and carbon pantograph-slide malfunctions.After experimentation and validation with actual surveillance videos of electric multiple-unit train,our algorithmic model demonstrates real-time,high-accuracy performance even under complex operational conditions.展开更多
BACKGROUND Due to their significantly lower incidence than colorectal polyps and macroscopic features resembling those of hyperplastic polyps,rectal neuroendocrine tumors(rNETs)are frequently misdiagnosed and resected...BACKGROUND Due to their significantly lower incidence than colorectal polyps and macroscopic features resembling those of hyperplastic polyps,rectal neuroendocrine tumors(rNETs)are frequently misdiagnosed and resected as polyps.To date,no reports have been written on the application of artificial intelligence for assisting in the white-light endoscopy of rNETs.AIM To establish a neuroendocrine tumor lesion detection algorithm based on the YOLOv7 model and evaluate the performance of the algorithm in identifying neuroendocrine tumors.METHODS In total,137748 white-light endoscopic images were collected in this study,including 2232 images of rNET,4429 images of submucosal lesions other than rNET,42563 images of polyps,and 88593 images of normal mucosa.All the images were randomly divided into a training set,a validation set,and a test set.To evaluate the ability of the algorithm to diagnose rNETs,we selected 1578 images to form the test set.The performance of the algorithm was compared with that of endoscopists at different levels.RESULTS The accuracy of the algorithm in identifying rNET from all the images was 97.8%,the sensitivity was 72.6%,the specificity was 99.7%,the positive predictive value was 93.9%,and the negative predictive value was 98.1%.CONCLUSION Our model,which was based on YOLOv7,could effectively detect rNET lesions,which was better than that of most endoscopists.展开更多
BACKGROUND Computer-aided diagnosis(CAD)may assist endoscopists in identifying and classifying polyps during colonoscopy for detecting colorectal cancer.AIM To build a system using CAD to detect and classify polyps ba...BACKGROUND Computer-aided diagnosis(CAD)may assist endoscopists in identifying and classifying polyps during colonoscopy for detecting colorectal cancer.AIM To build a system using CAD to detect and classify polyps based on the Yamada classification.METHODS A total of 24045 polyp and 72367 nonpolyp images were obtained.We established a computer-aided detection and Yamada classification model based on the YOLOv7 neural network algorithm.Frame-based and image-based evaluation metrics were employed to assess the performance.RESULTS Computer-aided detection and Yamada classification screened polyps with a precision of 96.7%,a recall of 95.8%,and an F1-score of 96.2%,outperforming those of all groups of endoscopists.In regard to the Yamada classification of polyps,the CAD system displayed a precision of 82.3%,a recall of 78.5%,and an F1-score of 80.2%,outper-forming all levels of endoscopists.In addition,according to the image-based method,the CAD had an accuracy of 99.2%,a specificity of 99.5%,a sensitivity of 98.5%,a positive predictive value of 99.0%,a negative predictive value of 99.2%for polyp detection and an accuracy of 97.2%,a specificity of 98.4%,a sensitivity of 79.2%,a positive predictive value of 83.0%,and a negative predictive value of 98.4%for poly Yamada classification.CONCLUSION We developed a novel CAD system based on a deep neural network for polyp detection,and the Yamada classi-fication outperformed that of nonexpert endoscopists.This CAD system could help community-based hospitals enhance their effectiveness in polyp detection and classification.展开更多
Copper–carbon(Cu–C)composites have achieved great success in various fields owing to the greatly improved electrical properties compared to pure Cu,for example,a two-order-of-magnitude increase in current-carrying c...Copper–carbon(Cu–C)composites have achieved great success in various fields owing to the greatly improved electrical properties compared to pure Cu,for example,a two-order-of-magnitude increase in current-carrying capacity(ampacity).However,the frequent fuse failure caused by the poor thermal transport at the Cu–C heterointerface is still the main factor affecting the ampacity.In this study,we unconventionally leverage atomic distortion at Cu grain boundaries to alter the local atomic environments,thereby placing a premium on noticeable enhancement of phonon coupling at the Cu–C heterointerface.Without introducing any additional materials,interfacial thermal transport can be regulated solely through rational microstructural design.This new strategy effectively improves the interfacial thermal conductance by three-fold,reaching the state-of-the-art level in van der Waals(vdW)interface regulation.It can be an innovative strategy for interfacial thermal management by turning the detrimental grain boundaries into a beneficial thermal transport accelerator.展开更多
Based on conventional particle swarm optimization(PSO),this paper presents an efficient and reliable heuristic approach using PSO with an adaptive random inertia weight(ARIW)strategy,referred to as the ARIW-PSO algori...Based on conventional particle swarm optimization(PSO),this paper presents an efficient and reliable heuristic approach using PSO with an adaptive random inertia weight(ARIW)strategy,referred to as the ARIW-PSO algorithm,to build a multi-objective optimization model for reservoir operation.Using the triangular probability density function,the inertia weight is randomly generated,and the probability density function is automatically adjusted to make the inertia weight generally greater in the initial stage of evolution,which is suitable for global searches.In the evolution process,the inertia weight gradually decreases,which is beneficial to local searches.The performance of the ARIWPSO algorithm was investigated with some classical test functions,and the results were compared with those of the genetic algorithm(GA),the conventional PSO,and other improved PSO methods.Then,the ARIW-PSO algorithm was applied to multi-objective optimal dispatch of the Panjiakou Reservoir and multi-objective flood control operation of a reservoir group on the Luanhe River in China,including the Panjiakou Reservoir,Daheiting Reservoir,and Taolinkou Reservoir.The validity of the multi-objective optimization model for multi-reservoir systems based on the ARIW-PSO algorithm was verified.展开更多
Smooth and strong copper foils are highly required for the development of printed circuit boards and Li-ion batteries.Adding additives is an efficient and low-cost method to enhance electrodeposited copper foils.Here ...Smooth and strong copper foils are highly required for the development of printed circuit boards and Li-ion batteries.Adding additives is an efficient and low-cost method to enhance electrodeposited copper foils.Here we chose Bis-(3-sulfopropyl)-disulfide(SPS)as the additive and investigated its concentration on the surface roughness and tensile strength of the electrodeposited copper foils.A copper foil with the smoothest surface(Rz=2.1μm)and the highest tensile strength(~338 MPa)was prepared with1.5 mg/L SPS.The contact angle on the copper foil decreased with the reduction of surface roughness.The enhancing mechanism of the SPS was investigated by scanning electron microscopy and X-ray diffraction.The refined grain and enhanced(220)texture were considered to be the radical reason for the smooth and strong copper foils.The electrochemical results prove the suppressing effect is related to the SPS adsorption.展开更多
In modern rail transportation,inverter drive systems have been extensively used due to their excellent speed control capabilities.However,in recent years,premature failure problems caused by bearing voltage and curren...In modern rail transportation,inverter drive systems have been extensively used due to their excellent speed control capabilities.However,in recent years,premature failure problems caused by bearing voltage and current phenomena have been frequently reported in electric motors,with electrical bearing failures making up a considerable percentage.The purpose of this review is to provide a comprehensive overview of facets relating to the electrical erosion of bearings in an electrical environment represented by railway vehicles.First,the origins of the phenomenon as well as typical bearing electrical failure modes are discussed.Next,we introduce the distinctive features of the electrical environment of railway traction motor bearings,including output voltages with high common-mode components and systems with complex grounding configurations.Then,we classify the fundamental mechanisms for generating bearing voltages/currents into four groups,and present their modeling processes,including equivalent circuit establishment and parameter determination methods.Furthermore,we summarize the strategies frequently used to protect bearings,and describe a typical solution to suppress electrical bearing failures in railway vehicles.Finally,we present a case example to illustrate a research procedure for systematic investigation of inverter-induced bearing currents in rail transportation.展开更多
The traction drive system is the“heart”of rail transit vehicles.The development of sustainable,secure,economic,reliable,efficient,and comfortable contemporary rail transportation has led to increasingly stringent re...The traction drive system is the“heart”of rail transit vehicles.The development of sustainable,secure,economic,reliable,efficient,and comfortable contemporary rail transportation has led to increasingly stringent requirements for traction drive systems.The interest in such systems is constantly growing,supported by advancements such as permanent magnet(PM)motors,advanced electronic devices such as those using silicon carbide(SiC),new-generation insulating materials such as organic silicon,and advanced magnetic materials such as rare-earth magnets and amorphous materials.Progress has also been made in control methods,manufacturing technology,artificial intelligence(AI),and other advanced technologies.In this paper,we briefly review the state-of-the-art critical global trends in rail transit traction drive technology in recent years.Potential areas for research and the main obstacles hindering the development of the next-generation rail transit traction drive systems are also discussed.Finally,we describe some advanced traction drive technologies used in actual engineering applications.展开更多
Nowadays,optimization techniques are required in various engineering domains to find optimal solutions for complex problems.As a result,there is a growing tendency among scientists to enhance existing nature-inspired ...Nowadays,optimization techniques are required in various engineering domains to find optimal solutions for complex problems.As a result,there is a growing tendency among scientists to enhance existing nature-inspired algorithms using various evolutionary strategies and to develop new nature-inspired optimization methods that can properly explore the feature space.The recently designed nature-inspired meta-heuristic,named the Golden Jackal Optimization(GJO),was inspired by the collaborative hunting actions of the golden jackal in nature to solve various challenging problems.However,like other approaches,the GJO has the limitations of poor exploitation ability,the ease of getting stuck in a local optimal region,and an improper balancing of exploration and exploitation.To overcome these limitations,this paper proposes an improved GJO algorithm based on multi-strategy mixing(LGJO).First,using a chaotic mapping strategy to initialize the population instead of using random parameters,this algorithm can generate initial solutions with good diversity in the search space.Second,a dynamic inertia weight based on cosine variation is proposed to make the search process more realistic and effectively balance the algorithm's global and local search capabilities.Finally,a position update strategy based on Gaussian mutation was introduced,fully utilizing the guidance role of the optimal individual to improve population diversity,effectively exploring unknown regions,and avoiding the algorithm falling into local optima.To evaluate the proposed algorithm,23 mathematical benchmark functions,CEC-2019 and CEC2021 tests are employed.The results are compared to high-quality,well-known optimization methods.The results of the proposed method are compared from different points of view,including the quality of the results,convergence behavior,and robustness.The superiority and high-quality performance of the proposed method are demonstrated by comparing the results.Furthermore,to demonstrate its applicability,it is employed to solve four constrained industrial applications.The outcomes of the experiment reveal that the proposed algorithm can solve challenging,constrained problems and is very competitive compared with other optimization algorithms.This article provides a new approach to solving real-world optimization problems.展开更多
We analyzed RNA-sequencing(RNA-seq)and clinical data from head and neck squamous cell carcinoma(HNSCC)patients in The Cancer Genome Atlas(TCGA)Genomic Data Commons(GDC)portal to investigate the prognostic value of ano...We analyzed RNA-sequencing(RNA-seq)and clinical data from head and neck squamous cell carcinoma(HNSCC)patients in The Cancer Genome Atlas(TCGA)Genomic Data Commons(GDC)portal to investigate the prognostic value of anoikis-related genes(ARGs)in HNSCC and develop new targeted drugs.Differentially expressed ARGs were screened using bioinformatics methods;subsequently,a prognostic model including three ARGs(CDKN2A,BIRC5,and PLAU)was constructed.Our results showed that the model-based risk score was a good prognostic indicator,and the potential of the three ARGs in HNSCC prognosis was validated by the TISCH database,the model’s accuracy was validated in two independent cohorts of the Gene Expression Omnibus database.Immune correlation analysis and half-maximal inhibitory concentration were also performed to reveal the different landscapes of TIME between risk groups and to predict immuno-and chemo-therapeutic responses.Potential small-molecule drugs for HNSCC were subsequently predicted using the L1000FWD database.Finally,in vitro experiments were used to verify the database findings.The relative ARG mRNA expression levels in HNSCC and surrounding normal tissues remained consistent with the model results.BIRC5 knockdown inhibited anoikis resistance in WSU-HN6 and CAL-27 cells.Molecular docking,real-time PCR,cell counting kit-8(CCK-8),plate clone,and flow cytometry analyses showed that small-molecule drugs predicted by the database may target the ARGs in the prognostic model,inhibit HNSCC cells survival rate,and promote anoikis in vitro.Therefore,we constructed a new ARG model for HNSCC patients that can predict prognosis and immune activity and identify a potential small-molecule drug for HNSCC,paving the way for clinically targeting anoikis in HNSCC.展开更多
目的:系统评价柴胡桂枝干姜汤加减治疗失眠的有效性。方法:通过检索中国期刊全文数据库(CNKI)、中文科技期刊数据库(VIP)、中国学术期刊数据库(CSPD)、PubMed和Web of Science,收集柴胡桂枝干姜汤加减治疗失眠的随机对照试验(RCT)。数...目的:系统评价柴胡桂枝干姜汤加减治疗失眠的有效性。方法:通过检索中国期刊全文数据库(CNKI)、中文科技期刊数据库(VIP)、中国学术期刊数据库(CSPD)、PubMed和Web of Science,收集柴胡桂枝干姜汤加减治疗失眠的随机对照试验(RCT)。数据分析采用RevMan 5.4软件,对纳入的研究进行Meta分析,评价其临床疗效总有效率、匹兹堡睡眠质量指数(PSQI)评分。结果:一共检索到148篇文献,共纳入10项研究,总计681例患者。Meta分析结果显示,柴胡桂枝干姜汤加减治疗失眠的临床总有效率显著高于对照组,差异有统计学意义(RR=1.36,95%CI为1.25~1.49,P<0.00001),且PSQI评分改善更显著,差异有统计学意义(MD=-2.28,95%CI为-3.70~-0.86,P=0.002)。结论:现有的研究证据表明,柴胡桂枝干姜汤加减治疗失眠可有效提高临床疗效,改善睡眠质量,且不良反应较少,具有良好的安全性。但目前尚未能证明其联合其他疗法在降低PSQI评分方面有明显优势。展开更多
基金supported by the National Natural Science Foundation of China(Nos.52222602,and52236006)the Fundamental Research Funds for the Central Universities(Nos.FRF-EYIT-23-05,and FRF-TP-22-001C1)+1 种基金Noncommunicable Chronic Diseases-National Science and Technology Major Project(No.2023ZD0500902)the member of the Youth Innovation Promotion Association Foundation of CAS,China(No.2023310)。
摘要Investigating thermal transport mechanisms at the interface between phase change materials(PCMs)and high thermally conductive fillers has become increasingly significant in developing phase change energy storage technologies.This study explores the interfacial thermal transport between a representative PCM,erythritol,and various fillers,including crystalline(Si C,Si3N4)and amorphous(Si O2)nanoparticles,using molecular dynamics(MD)simulations.Additionally,time-domain thermoreflectance(TDTR)experiments were performed to quantify the interfacial thermal conductance between erythritol and the three types of fillers,yielding values of 50.1,40.0,and25.6 MW m–2K-1.These results align well with the trends observed in the simulations.Furthermore,the underlying mechanisms of interfacial heat transfer were analyzed by examining the phonon density of states,overlap energy,and interaction energy.This research provides innovative insights into nanoscale interfacial thermal transport in composite PCMs.This could lead to significant advancements in thermal management technologies,particularly in developing more efficient thermal energy storage systems.
基金National Natural Science Foundation of China(Grant Nos.52560027,12274018,52473250,12374390,and 5222602,52501244)Jiangxi Provincial Natural Science Foundation(Grant No.20242BAB25145)+5 种基金Ph.D.Research Startup Foundation of Nanchang Hangkong University(Grant No.EA202502073)Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515111030)Noncommunicable Chronic Diseases-National Science and Technology Major Project(Grant No.2023ZD0500902)the Key Scientific and Technological Special Project of Ningbo City(Grant No.2023Z209)the Member of Youth Innovation Promotion Association Foundation of CAS(Grant No.2023310)Ningbo Youth Science and Technology Innovation Leading Talents Project(Grant No.2024QL029)。
摘要The detection of volatile organic compounds(VOCs)holds significant implications in environmental monitoring and disease diagnosis.Traditional gas detection technologies are constrained by complex operation and high cost,thereby failing to satisfy real-time detection demands.Surface-enhanced Raman scattering(SERS)provides a noble approach for trace VOCs detection,as it possesses single-molecule sensitivity,rapid response,and the ability to analyze chemical structures without being affected by water molecules.Researchers have successfully achieved precise identification of trace VOCs through the meticulous design of SERS substrates,demonstrating excellent application potential in practical detection.This review comprehensively summarizes the research progress and application of SERS technology in VOCs detection,covering the structural design of SERS substrates and the transformation of actual gas detection methods.Specifically,three core substrate structures include noble metal nanostructures,porous semiconductor composite nanostructures,and noble metal-semiconductor composite porous nanostructures that combine the advantages of both were delved into deeply.Furthermore,it also provides a detailed account of the technological innovations in VOCs detection based on SERS technology,expanding the application scope of SERS technology.Nevertheless,the SERS technology still faces significant challenges in VOC gas detection,including nonspecific adsorption in complex matrices,insufficient long-term substrate stability,the need to simultaneously identify multiple components in a mixed gas,etc.This review summarizes the current challenges in detail and looks forward to future research directions and development prospects.
基金supported by the National Key R&D Program of China(Grant No.2023YFF0612804)the National Natural Science Foundation of China(Grant Nos.52476052,W2521154,and 52236006)the Fundamental Research Funds for the Central Universities(Grant Nos.FRF-TP-22-001C1 and FRF-EYIT-23-05)。
摘要Phase-change memory(PCM),characterized by its reversible transition between crystalline and amorphous phases,has emerged as a promising candidate for neuromorphic memory computing applications.However,conventional PCM devices lack an insufficient RESET/SET voltage ratio,which often leads to incorrect recording of the RESET state and limits computational accuracy.In this work,we report a Ge2Sb2Te5-based PCM device achieving a record-breaking RESET/SET voltage ratio exceeding 10,significantly outperforming previously reported values below 5.This enhancement is enabled by an ultrathin(192 nm)architecture combined with a graded thermal conductivity design,which promotes a higher crystalline fraction,effectively reducing the SET voltage whereas maintaining a high RESET voltage.Furthermore,the nucleation and crystal growth mechanisms are systematically investigated,and the amorphous-crystalline phase transition is experimentally validated to enable rapid and reliable switching.These findings provide a new strategy for designing high-performance PCM devices and pave the way for more precise and efficient neuromorphic computing systems.
基金supported by the National Key R&D Program of China(Grant no.2024YFD1400900)the National Natural Science Foundation of China(Grant nos.32472557 and 31801736)the Science and Technology Innovation Program of Hunan Province(2022RC1025).
摘要Development and reproduction are key processes in the insect life cycle,and vitellogenesis is a critical event in insect reproduction.Vitellogenin(Vg)is generally recognized as a female-specific,reproductive lipoprotein unique to oviparous taxa that plays a crucial role in vitellogenesis.However,its specific functions,and the mechanisms underlying its regulation,remain poorly understood.We here demonstrate how 20hydroxyecdysone(20E)regulates Vg transcription via the transcription factor CsE74A and the ribosomal protein Cs40SRPS4 in Chilo suppressalis.Disruption of CsVg in G0 generation C.suppressalis via multiplex CRISPR/Cas9 resulted in decreased yolk deposition,ovarian dysplasia,and delayed oocyte maturation.Dual luciferase and DNA pull-down assays identified the CsVg core promoter(—915 to—811 bp)and its binding ribosomal protein Cs40SRPS4.Functional analysis via RNA interference revealed that Cs40SRPS4 is a ribosomal protein capable of regulating vitellogenesis in C.suppressalis.Furthermore,we correctly predicted that the binding site for CsE74A would be on the CsVg core promoter and confirmed its binding capability.Subsequent experiments further confirmed the interaction between CsE74A and Cs40SRPS4.Notably,the expression of CsE74A,Cs40S4,and CsVg significantly increased after 20E treatment.The results revealed that 20E induced the early response factor CsE74A to bind to the CsVg core promoter,thereby regulating Vg transcription and vitellogenesis in conjunction with Cs40SRPS4.These findings not only provide a foundation for gaining deeper understanding of insect reproductive processes,but could also lead to the development of safer,more economical and sustainable,pest control methods.
摘要Enabling as the second phase of the Production-Oriented Approach(POA)instruction(Wen,2015),plays a vital role in determining the quality of productive performance of English language learners.To explore how to apply theoretical principles of enabling to practice,this paper interprets theoretical principles and reports the practice of the classroom implementation of enabling.The paper proposes a definition for enabling,clarifies the confusion between enabling and scaffolding,and clears up some misunderstandings about enabling.It explains three criteria for effective enabling,namely,alignment,gradualness,and variety,and elaborates on the relations among them.Based on the teaching material of Unit 7 of iEnglish,the paper demonstrates how to design and implement enabling activities under the guidance of these three criteria and evaluates the actual effectiveness of the enabling implemented in the classroom.
基金financially supported by the National Natural Science Foundation of China(Nos.52473250,12274018,32311530040,5222602,and 12374390)the National Science and Technology Major Project(No.2023ZD0500902)+2 种基金the Key Scientific and Technological Special Project of Ningbo City(No.2023Z209)the Member of Youth Innovation Promotion Association Foundation of CAS(No.2023310)Ningbo Youth Science and Technology Innovation Leading Talents Project(No.2024QL029)
摘要The electromagnetic field coupling between two kinds of noble metal nanoparticles endows high surfaceenhanced Raman scattering(SERS) activity but is accompanied by uneven hot spots.Using two-dimensional semiconductors with localized surface plasmon resonance(LSPR) effects instead of one of the noble metal components can effectively improve uniformity.Hence,the Ag nanoparticles(Ag NPs) loaded MoO3-x nanoflowers(Ag/MoO3-x) were engineered to exploit dual-plasmonic coupling and realize the trace detection of aldehyde volatile organic compounds(VOCs) gas.The finite-difference time-domain(FDTD) simulation results proved that there is an obvious electromagnetic field coupling effect between Ag NPs and MoO3-x semiconductors,which can amplify the molecular dipole moment significantly.The chemical enhancement mechanism in the Ag/MoO3-x substrate was clarified by band structure analysis,in which the free electrons accumulated at the bottom of the conduction band of the MoO3-x semiconductor can promote the charge transfer process between Ag/MoO3-x and the 4-aminothiophenol(4-ATP) molecule.Moreover,the electron delocalization of 4-ATP molecule was enhanced after being absorbed on Ag/MoO3-x nanoflowers,facilitating the charge transfer between 4-ATP and Ag/MoO3-x substrate effectively.Importantly,using the 4-ATP molecule as a probe,the trace detection of a variety of aldehyde VOCs gas was realized by Ag/MoO3-x.substrate with a low limit of detection(LOD) of 10 ppb.This work provided a new idea for the design of noble metal-plasmonic semiconductor heterostructure substrates.
基金supported by the National Key R&D Program of China(No.2022YFB4301102).
摘要Currently,most trains are equipped with dedicated cameras for capturing pantograph videos.Pantographs are core to the high-speed-railway pantograph-catenary system,and their failure directly affects the normal operation of high-speed trains.However,given the complex and variable real-world operational conditions of high-speed railways,there is no real-time and robust pantograph fault-detection method capable of handling large volumes of surveillance video.Hence,it is of paramount importance to maintain real-time monitoring and analysis of pantographs.Our study presents a real-time intelligent detection technology for identifying faults in high-speed railway pantographs,utilizing a fusion of self-attention and convolution features.We delved into lightweight multi-scale feature-extraction and fault-detection models based on deep learning to detect pantograph anomalies.Compared with traditional methods,this approach achieves high recall and accuracy in pantograph recognition,accurately pinpointing issues like discharge sparks,pantograph horns,and carbon pantograph-slide malfunctions.After experimentation and validation with actual surveillance videos of electric multiple-unit train,our algorithmic model demonstrates real-time,high-accuracy performance even under complex operational conditions.
基金Supported by the Municipal Key Science and Technology Program of Leshan,No.23SZD039National Natural Science Foundation of China,No.82470539.
摘要BACKGROUND Due to their significantly lower incidence than colorectal polyps and macroscopic features resembling those of hyperplastic polyps,rectal neuroendocrine tumors(rNETs)are frequently misdiagnosed and resected as polyps.To date,no reports have been written on the application of artificial intelligence for assisting in the white-light endoscopy of rNETs.AIM To establish a neuroendocrine tumor lesion detection algorithm based on the YOLOv7 model and evaluate the performance of the algorithm in identifying neuroendocrine tumors.METHODS In total,137748 white-light endoscopic images were collected in this study,including 2232 images of rNET,4429 images of submucosal lesions other than rNET,42563 images of polyps,and 88593 images of normal mucosa.All the images were randomly divided into a training set,a validation set,and a test set.To evaluate the ability of the algorithm to diagnose rNETs,we selected 1578 images to form the test set.The performance of the algorithm was compared with that of endoscopists at different levels.RESULTS The accuracy of the algorithm in identifying rNET from all the images was 97.8%,the sensitivity was 72.6%,the specificity was 99.7%,the positive predictive value was 93.9%,and the negative predictive value was 98.1%.CONCLUSION Our model,which was based on YOLOv7,could effectively detect rNET lesions,which was better than that of most endoscopists.
基金Supported by Science and Technology Projects in Guangzhou,No.2023A04J2282。
摘要BACKGROUND Computer-aided diagnosis(CAD)may assist endoscopists in identifying and classifying polyps during colonoscopy for detecting colorectal cancer.AIM To build a system using CAD to detect and classify polyps based on the Yamada classification.METHODS A total of 24045 polyp and 72367 nonpolyp images were obtained.We established a computer-aided detection and Yamada classification model based on the YOLOv7 neural network algorithm.Frame-based and image-based evaluation metrics were employed to assess the performance.RESULTS Computer-aided detection and Yamada classification screened polyps with a precision of 96.7%,a recall of 95.8%,and an F1-score of 96.2%,outperforming those of all groups of endoscopists.In regard to the Yamada classification of polyps,the CAD system displayed a precision of 82.3%,a recall of 78.5%,and an F1-score of 80.2%,outper-forming all levels of endoscopists.In addition,according to the image-based method,the CAD had an accuracy of 99.2%,a specificity of 99.5%,a sensitivity of 98.5%,a positive predictive value of 99.0%,a negative predictive value of 99.2%for polyp detection and an accuracy of 97.2%,a specificity of 98.4%,a sensitivity of 79.2%,a positive predictive value of 83.0%,and a negative predictive value of 98.4%for poly Yamada classification.CONCLUSION We developed a novel CAD system based on a deep neural network for polyp detection,and the Yamada classi-fication outperformed that of nonexpert endoscopists.This CAD system could help community-based hospitals enhance their effectiveness in polyp detection and classification.
基金financial support from the National Natural Science Foundation of China(Nos.52222602 and 52476052)Fundamental Research Funds for the Central Universities(FRF-TP-22-001C1 and FRF-EYIT-23-05).
摘要Copper–carbon(Cu–C)composites have achieved great success in various fields owing to the greatly improved electrical properties compared to pure Cu,for example,a two-order-of-magnitude increase in current-carrying capacity(ampacity).However,the frequent fuse failure caused by the poor thermal transport at the Cu–C heterointerface is still the main factor affecting the ampacity.In this study,we unconventionally leverage atomic distortion at Cu grain boundaries to alter the local atomic environments,thereby placing a premium on noticeable enhancement of phonon coupling at the Cu–C heterointerface.Without introducing any additional materials,interfacial thermal transport can be regulated solely through rational microstructural design.This new strategy effectively improves the interfacial thermal conductance by three-fold,reaching the state-of-the-art level in van der Waals(vdW)interface regulation.It can be an innovative strategy for interfacial thermal management by turning the detrimental grain boundaries into a beneficial thermal transport accelerator.
基金supported by the Foundation of the Scientific and Technological Innovation Team of Colleges and Universities in Henan Province(Grant No.181RTSTHN009)the Foundation of the Key Laboratory of Water Environment Simulation and Treatment in Henan Province(Grant No.2017016).
摘要Based on conventional particle swarm optimization(PSO),this paper presents an efficient and reliable heuristic approach using PSO with an adaptive random inertia weight(ARIW)strategy,referred to as the ARIW-PSO algorithm,to build a multi-objective optimization model for reservoir operation.Using the triangular probability density function,the inertia weight is randomly generated,and the probability density function is automatically adjusted to make the inertia weight generally greater in the initial stage of evolution,which is suitable for global searches.In the evolution process,the inertia weight gradually decreases,which is beneficial to local searches.The performance of the ARIWPSO algorithm was investigated with some classical test functions,and the results were compared with those of the genetic algorithm(GA),the conventional PSO,and other improved PSO methods.Then,the ARIW-PSO algorithm was applied to multi-objective optimal dispatch of the Panjiakou Reservoir and multi-objective flood control operation of a reservoir group on the Luanhe River in China,including the Panjiakou Reservoir,Daheiting Reservoir,and Taolinkou Reservoir.The validity of the multi-objective optimization model for multi-reservoir systems based on the ARIW-PSO algorithm was verified.
基金the National Key R&D Program of China(No.2017YFB1200800)the National Natural Science Foundation of China(Nos.51827810 and 51637009)the Fundamental Research Funds for the Central Universities(2018XZZX001-05)。
摘要Smooth and strong copper foils are highly required for the development of printed circuit boards and Li-ion batteries.Adding additives is an efficient and low-cost method to enhance electrodeposited copper foils.Here we chose Bis-(3-sulfopropyl)-disulfide(SPS)as the additive and investigated its concentration on the surface roughness and tensile strength of the electrodeposited copper foils.A copper foil with the smoothest surface(Rz=2.1μm)and the highest tensile strength(~338 MPa)was prepared with1.5 mg/L SPS.The contact angle on the copper foil decreased with the reduction of surface roughness.The enhancing mechanism of the SPS was investigated by scanning electron microscopy and X-ray diffraction.The refined grain and enhanced(220)texture were considered to be the radical reason for the smooth and strong copper foils.The electrochemical results prove the suppressing effect is related to the SPS adsorption.
基金supported by the National Key R&D Program of China(No.2018YFB1201804)the National Natural Science Foundation of China(Nos.52293424,51827810,and 51977192).
摘要In modern rail transportation,inverter drive systems have been extensively used due to their excellent speed control capabilities.However,in recent years,premature failure problems caused by bearing voltage and current phenomena have been frequently reported in electric motors,with electrical bearing failures making up a considerable percentage.The purpose of this review is to provide a comprehensive overview of facets relating to the electrical erosion of bearings in an electrical environment represented by railway vehicles.First,the origins of the phenomenon as well as typical bearing electrical failure modes are discussed.Next,we introduce the distinctive features of the electrical environment of railway traction motor bearings,including output voltages with high common-mode components and systems with complex grounding configurations.Then,we classify the fundamental mechanisms for generating bearing voltages/currents into four groups,and present their modeling processes,including equivalent circuit establishment and parameter determination methods.Furthermore,we summarize the strategies frequently used to protect bearings,and describe a typical solution to suppress electrical bearing failures in railway vehicles.Finally,we present a case example to illustrate a research procedure for systematic investigation of inverter-induced bearing currents in rail transportation.
基金supported by the National Key Research and Development Program of China(No.2018YFB1201804)the Science and Technology Research and Development Plan of China State Railway Group Co.,Ltd.(No.N2021J049).
摘要The traction drive system is the“heart”of rail transit vehicles.The development of sustainable,secure,economic,reliable,efficient,and comfortable contemporary rail transportation has led to increasingly stringent requirements for traction drive systems.The interest in such systems is constantly growing,supported by advancements such as permanent magnet(PM)motors,advanced electronic devices such as those using silicon carbide(SiC),new-generation insulating materials such as organic silicon,and advanced magnetic materials such as rare-earth magnets and amorphous materials.Progress has also been made in control methods,manufacturing technology,artificial intelligence(AI),and other advanced technologies.In this paper,we briefly review the state-of-the-art critical global trends in rail transit traction drive technology in recent years.Potential areas for research and the main obstacles hindering the development of the next-generation rail transit traction drive systems are also discussed.Finally,we describe some advanced traction drive technologies used in actual engineering applications.
基金support of the special project for collaborative innovation of science and technology in 2021(No:202121206)Henan Province University Scientific and Technological Innovation Team(No:18IRTSTHN009).
摘要Nowadays,optimization techniques are required in various engineering domains to find optimal solutions for complex problems.As a result,there is a growing tendency among scientists to enhance existing nature-inspired algorithms using various evolutionary strategies and to develop new nature-inspired optimization methods that can properly explore the feature space.The recently designed nature-inspired meta-heuristic,named the Golden Jackal Optimization(GJO),was inspired by the collaborative hunting actions of the golden jackal in nature to solve various challenging problems.However,like other approaches,the GJO has the limitations of poor exploitation ability,the ease of getting stuck in a local optimal region,and an improper balancing of exploration and exploitation.To overcome these limitations,this paper proposes an improved GJO algorithm based on multi-strategy mixing(LGJO).First,using a chaotic mapping strategy to initialize the population instead of using random parameters,this algorithm can generate initial solutions with good diversity in the search space.Second,a dynamic inertia weight based on cosine variation is proposed to make the search process more realistic and effectively balance the algorithm's global and local search capabilities.Finally,a position update strategy based on Gaussian mutation was introduced,fully utilizing the guidance role of the optimal individual to improve population diversity,effectively exploring unknown regions,and avoiding the algorithm falling into local optima.To evaluate the proposed algorithm,23 mathematical benchmark functions,CEC-2019 and CEC2021 tests are employed.The results are compared to high-quality,well-known optimization methods.The results of the proposed method are compared from different points of view,including the quality of the results,convergence behavior,and robustness.The superiority and high-quality performance of the proposed method are demonstrated by comparing the results.Furthermore,to demonstrate its applicability,it is employed to solve four constrained industrial applications.The outcomes of the experiment reveal that the proposed algorithm can solve challenging,constrained problems and is very competitive compared with other optimization algorithms.This article provides a new approach to solving real-world optimization problems.
基金supported by the National Nature Science Foundation of China(Grant Numbers 81072214,30371547)the National Key R&D Program of China(Grant Number 2016YFC1102603).
摘要We analyzed RNA-sequencing(RNA-seq)and clinical data from head and neck squamous cell carcinoma(HNSCC)patients in The Cancer Genome Atlas(TCGA)Genomic Data Commons(GDC)portal to investigate the prognostic value of anoikis-related genes(ARGs)in HNSCC and develop new targeted drugs.Differentially expressed ARGs were screened using bioinformatics methods;subsequently,a prognostic model including three ARGs(CDKN2A,BIRC5,and PLAU)was constructed.Our results showed that the model-based risk score was a good prognostic indicator,and the potential of the three ARGs in HNSCC prognosis was validated by the TISCH database,the model’s accuracy was validated in two independent cohorts of the Gene Expression Omnibus database.Immune correlation analysis and half-maximal inhibitory concentration were also performed to reveal the different landscapes of TIME between risk groups and to predict immuno-and chemo-therapeutic responses.Potential small-molecule drugs for HNSCC were subsequently predicted using the L1000FWD database.Finally,in vitro experiments were used to verify the database findings.The relative ARG mRNA expression levels in HNSCC and surrounding normal tissues remained consistent with the model results.BIRC5 knockdown inhibited anoikis resistance in WSU-HN6 and CAL-27 cells.Molecular docking,real-time PCR,cell counting kit-8(CCK-8),plate clone,and flow cytometry analyses showed that small-molecule drugs predicted by the database may target the ARGs in the prognostic model,inhibit HNSCC cells survival rate,and promote anoikis in vitro.Therefore,we constructed a new ARG model for HNSCC patients that can predict prognosis and immune activity and identify a potential small-molecule drug for HNSCC,paving the way for clinically targeting anoikis in HNSCC.
摘要目的:系统评价柴胡桂枝干姜汤加减治疗失眠的有效性。方法:通过检索中国期刊全文数据库(CNKI)、中文科技期刊数据库(VIP)、中国学术期刊数据库(CSPD)、PubMed和Web of Science,收集柴胡桂枝干姜汤加减治疗失眠的随机对照试验(RCT)。数据分析采用RevMan 5.4软件,对纳入的研究进行Meta分析,评价其临床疗效总有效率、匹兹堡睡眠质量指数(PSQI)评分。结果:一共检索到148篇文献,共纳入10项研究,总计681例患者。Meta分析结果显示,柴胡桂枝干姜汤加减治疗失眠的临床总有效率显著高于对照组,差异有统计学意义(RR=1.36,95%CI为1.25~1.49,P<0.00001),且PSQI评分改善更显著,差异有统计学意义(MD=-2.28,95%CI为-3.70~-0.86,P=0.002)。结论:现有的研究证据表明,柴胡桂枝干姜汤加减治疗失眠可有效提高临床疗效,改善睡眠质量,且不良反应较少,具有良好的安全性。但目前尚未能证明其联合其他疗法在降低PSQI评分方面有明显优势。