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Analysis of application range of simplified models for field to thermo-field to thermionic emission processes from the cathode
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作者 Li SUN Zhuo DAI +2 位作者 ming xu Wei WANG Zengyao LI 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第9期51-60,共10页
Electron emission plays a dominant role in plasma-cathode interactions and is a key factor in many plasma phenomena and industrial applications.It is necessary to illustrate the various electron emission mechanisms an... Electron emission plays a dominant role in plasma-cathode interactions and is a key factor in many plasma phenomena and industrial applications.It is necessary to illustrate the various electron emission mechanisms and the corresponding applicable description models to evaluate their impacts on discharge properties.In this study,detailed expressions of the simplified formulas valid for field emission to thermo-field emission to thermionic emission typically used in the numerical simulation are proposed,and the corresponding application ranges are determined in the framework of the Murphy-Good theory,which is commonly regarded as the general model and to be accurate in the full range of conditions of the validity of the theory.Dimensionless parameterization was used to evaluate the emission current density of the Murphy-Good formula,and a deviation factor was defined to obtain the application ranges for different work functions(2.5‒5 eV),cathode temperatures(300‒6000 K),and emitted electric fields(10^(5) to 10^(10) V·m^(-1)).The deviation factor was shown to be a nonmonotonic function of the three parameters.A comparative study of particle number densities in atmospheric gas discharge with a tungsten cathode was performed based on the one-dimensional implicit particle-in-cell(PIC)with the Monte Carlo collision(MCC)method according to the aforementioned application ranges.It was found that small differences in emission current density can lead to variations in the distributions of particle number density due to changes in the collisional environment.This study provides a theoretical basis for selecting emission models for subsequent numerical simulations. 展开更多
关键词 electron emission processes application range Murphy-Good theory implicit particlein-cell Monte Carlo collision method
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Reconfigurable and polarization-dependent optical filtering for transflective full-color generation utilizing low-loss phase-change materials
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作者 Shuo Deng Mengxi Cui +7 位作者 Jingru Jiang Chuang Wang Zengguang Cheng Huajun Sun ming xu Hao Tong Qiang He Xiangshui Miao 《Journal of Semiconductors》 EI CAS CSCD 2024年第7期46-53,共8页
All-dielectric metasurface, which features low optical absorptance and high resolution, is becoming a promising candidate for full-color generation. However, the optical response of current metamaterials is fixed and ... All-dielectric metasurface, which features low optical absorptance and high resolution, is becoming a promising candidate for full-color generation. However, the optical response of current metamaterials is fixed and lacks active tuning. In this work, we demonstrate a reconfigurable and polarization-dependent active color generation technique by incorporating low-loss phase change materials(PCMs) and CaF_2 all-dielectric substrate. Based on the strong Mie resonance effect and low optical absorption structure, a transflective, full-color with high color purity and gamut value is achieved. The spectrum can be dynamically manipulated by changing either the polarization of incident light or the PCM state. High transmittance and reflectance can be simultaneously achieved by using low-loss PCMs and substrate. The novel active metasurfaces can bring new inspiration in the areas of optical encryption, anti-counterfeiting, and display technologies. 展开更多
关键词 structural color RECONFIGURABLE all-dielectric metasurfaces phase change material
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Simulation of charge-exchange induced NBI losses on EAST
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作者 Zhanhong LIN Feng WANG +3 位作者 ming xu Chaofeng SANG Chen ZHANG Zhengxiong WANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第9期133-147,共15页
The neutral beam injection is widely adopted in tokamaks as a key heating tool,playing a crucial role in generating burning plasmas.However,the loss of beam ions can damage the first wall and reduce the heating effici... The neutral beam injection is widely adopted in tokamaks as a key heating tool,playing a crucial role in generating burning plasmas.However,the loss of beam ions can damage the first wall and reduce the heating efficiency,resulting in failure to maintain steady-state conditions.In this work,the effect of neutral particles in the edge on fast ions generated by NBI in the Experimental Advanced Superconducting Tokamak(EAST)device is studied using the particle tracer code(PTC).The poloidal distribution of neutral particles is calculated by edge plasma simulation code SOLPS-ITER.In this simulation,four beam lines in EAST are considered:co-current tangential(co-tang),co-current perpendicular(co-perp),counter-current tangential(ctr-tang)and counter-current perpendicular(ctr-perp).It is shown that,in the absence of neutral particles,the loss fraction of ctr-injection is considerably higher than that of the co-injection.When considering the neutral particles,it is found that the ctr-perp injection demonstrates a significant variation in particles loss fraction(ranging from 18.56%to 25.42%)compared to the other three injection configurations.In terms of the loss fraction induced by neutral particles,ctr-injection exceeds co-injection,and perpendicular configuration exceeds tangential configuration.Furthermore,the difference of charge exchange ratios of three different energy(full energy,half energy,one third energy)of the four injections can be attributed to variations in the poloidal trajectories associated with each of these injections.Moreover,approximately half of fast ions which undergo neutralization directly lose to the first wall while the rest re-enter the bulk plasma and re-ionize.Except for the ctr-tang injection,the reionization ions from the other three injections exhibit effective confinement. 展开更多
关键词 NBI charge exchange fast ion loss
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Research progress of tumor-associated macrophages in immune checkpoint inhibitor tolerance in colorectal cancer
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作者 Qi Fan Zheng-Wei Fu +4 位作者 ming xu Feng Lv Jia-Song Shi Qi-Qi Zeng De-Hai Xiong 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第10期4064-4079,共16页
The relevant mechanism of tumor-associated macrophages(TAMs)in the treatment of colorectal cancer patients with immune checkpoint inhibitors(ICIs)is discussed,and the application prospects of TAMs in reversing the tre... The relevant mechanism of tumor-associated macrophages(TAMs)in the treatment of colorectal cancer patients with immune checkpoint inhibitors(ICIs)is discussed,and the application prospects of TAMs in reversing the treatment tolerance of ICIs are discussed to provide a reference for related studies.As a class of drugs widely used in clinical tumor immunotherapy,ICIs can act on regulatory molecules on cells that play an inhibitory role-immune checkpoints-and kill tumors in the form of an immune response by activating a variety of immune cells in the immune system.The sensitivity of patients with different types of colorectal cancer to ICI treatment varies greatly.The phenotype and function of TAMs in the colorectal cancer microenvironment are closely related to the efficacy of ICIs.ICIs can regulate the phenotypic function of TAMs,and TAMs can also affect the tolerance of colorectal cancer to ICI therapy.TAMs play an important role in ICI resistance,and making full use of this target as a therapeutic strategy is expected to improve the immunotherapy efficacy and prognosis of patients with colorectal cancer. 展开更多
关键词 Colorectal cancer Immune checkpoint inhibitor resistance Tumor microenvironment Tumor-associated macrophages REVIEW
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Design and Implementation of a High-Sensitivity Magnetic Sensing System Based on GMI Effect
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作者 Wenzhu Wu ming xu +4 位作者 Changlin Han Junquan Tang Jia xu Lin xu mingxin Qin 《Journal of Beijing Institute of Technology》 EI CAS 2024年第3期237-247,共11页
A high-sensitivity magnetic sensing system based on giant magneto-impedance(GMI)effect is designed and fabricated.The system comprises a GMI sensor equipped with a gradient probe and an signal acquisition and processi... A high-sensitivity magnetic sensing system based on giant magneto-impedance(GMI)effect is designed and fabricated.The system comprises a GMI sensor equipped with a gradient probe and an signal acquisition and processing module.A segmented superposition algorithm is used to increase target signal and reduce the random noise.The results show that under unshielded,room temperature conditions,the system achieves successful detection of weak magnetic fields down to 2 pT with a notable sensitivity of 1.84×10^(8)V/T(G=1000).By applying 17 overlays,the segmented superposition algorithm increases the power proportion of the target signal at 31 Hz from6.89%to 45.91%,surpassing the power proportion of the 2 Hz low-frequency interference signal.Simultaneously,it reduces the power proportion of the 20 Hz random noise.The segmented superposition process effectively cancels out certain random noise elements,leading to a reduction in their respective power proportions.This high-sensitivity magnetic sensing system features a simple structure,and is easy to operate,making it highly valuable for both practical applications and broader dissemination. 展开更多
关键词 HIGH-SENSITIVITY magnetic field sensing system GMI effect segmented superposition algorithm
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Effectiveness of colonoscopy,immune fecal occult blood testing,and risk-graded screening strategies in colorectal cancer screening
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作者 ming xu Jing-Yi Yang Tao Meng 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第7期2270-2280,共11页
BACKGROUND Colorectal cancer(CRC)is one of the most common malignant tumors,and early screening is crucial to improving the survival rate of patients.The combination of colonoscopy and immune fecal occult blood detect... BACKGROUND Colorectal cancer(CRC)is one of the most common malignant tumors,and early screening is crucial to improving the survival rate of patients.The combination of colonoscopy and immune fecal occult blood detection has garnered significant attention as a novel method for CRC screening.Colonoscopy and fecal occult blood tests,when combined,can improve screening accuracy and early detection rates,thereby facilitating early intervention and treatment.However,certain risks and costs accompany it,making the establishment of a risk classification model crucial for accurate classification and management of screened subjects.AIM To evaluate the feasibility and effectiveness of colonoscopy,immune fecal occult blood test(FIT),and risk-graded screening strategies in CRC screening.METHODS Based on the randomized controlled trial of CRC screening in the population conducted by our hospital May 2020 to May 2023,participants who met the requirements were randomly assigned to a colonoscopy group,an FIT group,or a graded screening group at a ratio of 1:2:2(after risk assessment,the high-risk group received colonoscopy,the low-risk group received an FIT test,and the FITpositive group received colonoscopy).The three groups received CRC screening with different protocols,among which the colonoscopy group only received baseline screening,and the FIT group and the graded screening group received annual follow-up screening based on baseline screening.The primary outcome was the detection rate of advanced tumors,including CRC and advanced adenoma.The population participation rate,advanced tumor detection rate,and colonoscopy load of the three screening programs were compared.RESULTS A total of 19373 subjects who met the inclusion and exclusion criteria were enrolled,including 8082 males(41.7%)and 11291 females(58.3%).The mean age was 60.05±6.5 years.Among them,3883 patients were enrolled in the colonoscopy group,7793 in the FIT group,and 7697 in the graded screening group.Two rounds of follow-up screening were completed in the FIT group and the graded screening group.The graded screening group(89.2%)and the colonoscopy group(42.3%)had the lowest overall screening participation rates,while the FIT group had the highest(99.3%).The results of the intentional analysis showed that the detection rate of advanced tumors in the colonoscopy group was greater than that of the FIT group[2.76%vs 2.17%,odds ratio(OR)=1.30,95%confidence interval(CI):1.01-1.65,P=0.037].There was no significant difference in the detection rate of advanced tumors between the colonoscopy group and the graded screening group(2.76%vs 2.35%,OR=1.9,95%CI:0.93-1.51,P=0.156),as well as between the graded screening group and the FIT group(2.35%vs 2.17%,OR=1.09%,95%CI:0.88-1.34,P=0.440).The number of colonoscopy examinations required for each patient with advanced tumors was used as an index to evaluate the colonoscopy load during population screening.The graded screening group had the highest colonoscopy load(15.4 times),followed by the colonoscopy group(10.2 times),and the FIT group had the lowest(7.8 times).CONCLUSION A hierarchical screening strategy based on CRC risk assessment is feasible for screening for CRC in the population.It can be used as an effective supplement to traditional colonoscopy and FIT screening programs. 展开更多
关键词 Colorectal tumor Immune fecal occult blood testing COLONOSCOPY Hierarchical screening Risk assessment
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Ultrasomics in liver cancer: Developing a radiomics model for differentiating intrahepatic cholangiocarcinoma from hepatocellular carcinoma using contrast-enhanced ultrasound
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作者 Li-Ya Su ming xu +2 位作者 Yan-Lin Chen Man-Xia Lin Xiao-Yan Xie 《World Journal of Radiology》 2024年第7期247-255,共9页
BACKGROUND Hepatocellular carcinoma(HCC)and intrahepatic cholangiocarcinoma(ICC)represent the predominant histological types of primary liver cancer,comprising over 99%of cases.Given their differing biological behavio... BACKGROUND Hepatocellular carcinoma(HCC)and intrahepatic cholangiocarcinoma(ICC)represent the predominant histological types of primary liver cancer,comprising over 99%of cases.Given their differing biological behaviors,prognoses,and treatment strategies,accurately differentiating between HCC and ICC is crucial for effective clinical management.Radiomics,an emerging image processing technology,can automatically extract various quantitative image features that may elude the human eye.Reports on the application of ultrasound(US)-based radiomics methods in distinguishing HCC from ICC are limited.METHODS In our retrospective study,we included a total of 280 patients who were diagnosed with ICC(n=140)and HCC(n=140)between 1999 and 2019.These patients were divided into training(n=224)and testing(n=56)groups for analysis.US images and relevant clinical characteristics were collected.We utilized the XGBoost method to extract and select radiomics features and further employed a random forest algorithm to establish ultrasomics models.We compared the diagnostic performances of these ultrasomics models with that of radiologists.RESULTS Four distinct ultrasomics models were constructed,with the number of selected features varying between models:13 features for the US model;15 for the contrast-enhanced ultrasound(CEUS)model;13 for the combined US+CEUS model;and 21 for the US+CEUS+clinical data model.The US+CEUS+clinical data model yielded the highest area under the receiver operating characteristic curve(AUC)among all models,achieving an AUC of 0.973 in the validation cohort and 0.971 in the test cohort.This performance exceeded even the most experienced radiologist(AUC=0.964).The AUC for the US+CEUS model(training cohort AUC=0.964,test cohort AUC=0.955)was significantly higher than that of the US model alone(training cohort AUC=0.822,test cohort AUC=0.816).This finding underscored the significant benefit of incorporating CEUS information in accurately distin-guishing ICC from HCC.CONCLUSION We developed a radiomics diagnostic model based on CEUS images capable of quickly distinguishing HCC from ICC,which outperformed experienced radiologists. 展开更多
关键词 CHOLANGIOCARCINOMA Hepatocellular carcinoma Contrast-enhanced ultrasound Radiomics Primary liver tumor
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Research on Risk Assessment Method of Long-Tube Trailer Road Transportation
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作者 Caiyan Dai Wenkun Wang +4 位作者 ming xu Chenglong Ma Lianqing Yang Hong Zhao Yuan He 《Journal of Software Engineering and Applications》 2023年第8期420-441,共22页
Road transport safety has always been paid attention to by the safety production managers of enterprises. In this study, cloud model and analytic hierarchy process were applied to the safety of long-tube trailer trans... Road transport safety has always been paid attention to by the safety production managers of enterprises. In this study, cloud model and analytic hierarchy process were applied to the safety of long-tube trailer transport. The opinions of 30 experts were analyzed, from which 29 key parameters were selected. The study addressed the relevance of the parameters and the possibility of automatic collection and transmission to obtain 12 core risk factors. The macro-safety risk indicator system for long-tube trailers was established based on the identified risk indicators. Finally, a risk assessment model for road transport of long tube trailers consisting of 3 dimensions of likelihood, severity and sensitivity was constructed. This model provides a technical method for strengthening the risk control of road transport of long-tube trailers. 展开更多
关键词 Cloud Model Analytic Hierarchy Process Long-Tube Trailer Risk Factors Risk Assessment Model
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碳酸盐炼制共热耦合甲烷干重整制高附加值化学品发展展望 被引量:1
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作者 尹倩 宋慧婷 +3 位作者 徐明 鄢红 赵宇飞 段雪 《物理化学学报》 SCIE CAS CSCD 北大核心 2023年第3期1-9,共9页
传统过程工业,诸如我国水泥、钢铁、耐材和电石等行业,都涉及碳酸盐高温热分解过程,其导致的CO_(2)排放量超过了全国工业碳排放总量的50%,大量CO_(2)排放对全球气候产生了不可逆转的影响。因此,如何减少过程工业排放的CO_(2)并且充分利... 传统过程工业,诸如我国水泥、钢铁、耐材和电石等行业,都涉及碳酸盐高温热分解过程,其导致的CO_(2)排放量超过了全国工业碳排放总量的50%,大量CO_(2)排放对全球气候产生了不可逆转的影响。因此,如何减少过程工业排放的CO_(2)并且充分利用碳酸盐热分解的余热面临着巨大挑战。为进一步降低该类过程工业的CO_(2)排放量同时降低其热分解的能耗,通过利用地球上储量丰富的温室气体CH_(4),对碳酸盐进行共热耦合重整制备合成气等高附加值产品,有望成为一种环保经济的技术路线。本文总结了(光/热)碳酸盐炼制耦合甲烷干重整反应、醇类重整反应以及CO_(2)捕获反应的最新进展,并且对碳酸盐炼制耦合甲烷干重整反应在理论计算方面的研究进展进行了介绍,进一步结合本课题组近期关于碳酸盐共热耦合甲烷重整的最新结果,我们提出了该类耦合反应的发展展望,为实现CO_(2)的高效转化和减排增效提供了思路。 展开更多
关键词 碳酸盐 甲烷干重整 耦合反应 碳减排
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引入动态虚拟感抗的虚拟机协调控制策略
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作者 郭劭杰 蒋强 +1 位作者 明旭 常峰 《电力电子技术》 北大核心 2023年第10期93-96,共4页
在交流微电网离网状态运行时,由于线路阻抗不平衡以及功率耦合等原因,传统虚拟同步机(VSG)控制往往存在着无功功率分配不均的问题。此处以VSG控制下的储能变换器为例,提出了一种引入动态虚拟感抗的VSG并联协调控制方法。该方法化简了传... 在交流微电网离网状态运行时,由于线路阻抗不平衡以及功率耦合等原因,传统虚拟同步机(VSG)控制往往存在着无功功率分配不均的问题。此处以VSG控制下的储能变换器为例,提出了一种引入动态虚拟感抗的VSG并联协调控制方法。该方法化简了传统VSG中的定子电压方程使其阻抗呈纯感性,通过引入动态补偿环节根据输出无功功率的差异调节感抗,最终实现了两台储能变换器无功输出功率的均衡。仿真和实验结果验证了所提方法的可行性和有效性。 展开更多
关键词 微电网 虚拟同步机 动态虚拟感抗 无功功率分配
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A comparative study on Sn macrosegregation behavior of ternary Al-Sn-Cu alloys prepared by gravity casting and squeeze casting 被引量:2
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作者 ming xu Yan-guo Yin +1 位作者 Cong-min Li Cong-chong Duan 《China Foundry》 SCIE CAS CSCD 2023年第1期63-70,共8页
A comprehensive study on Sn macrosegregation behavior in ternary Al-Sn-Cu alloys was carried out by comparative analysis between gravity casting and squeeze casting samples.The microstructure and Sn distribution of th... A comprehensive study on Sn macrosegregation behavior in ternary Al-Sn-Cu alloys was carried out by comparative analysis between gravity casting and squeeze casting samples.The microstructure and Sn distribution of the castings were characterized by metallography,scanning electron microscopy(SEM),energy-dispersive X-ray(EDX)spectroscopy,and a direct reading spectrometer.Results show that there are obvious differences in Sn morphology between gravity casting and squeeze casting alloys.Under squeeze casting condition,the grain size of the casting is smaller and the distribution ofβ(Sn)is uniform.This effectively reduces the segregation of triangular grain boundary as well as the segregation of Sn.The segregation types of Sn in gravity casting and squeeze casting samples are obviously different.The upper surfaces of gravity casting samples show severe negative segregation,while all the lower surfaces have positive segregation.Compared with gravity casting,squeeze casting solidifies under isostatic pressure.Due to the direct contact between the upper surface of the casting and the mold,the casting solidifies faster under higher undercooling degree and pressure.Consequently,the uniform distribution of Sn reduces the segregation phenomenon on the surface of the casting. 展开更多
关键词 ternary Al-Sn-Cu alloy squeeze casting MACROSEGREGATION mechanism
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Emerging role of engineered exosomes in nonalcoholic fatty liver disease 被引量:2
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作者 Jian Ding Chen xu +3 位作者 ming xu Xiao-Yue He Wei-Na Li Fei He 《World Journal of Hepatology》 2023年第3期386-392,共7页
Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver dis-ease worldwide.NAFLD comprises a continuum of liver abnormalities from non-alcoholic fatty liver to nonalcoholic steatohepatitis,and can even... Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver dis-ease worldwide.NAFLD comprises a continuum of liver abnormalities from non-alcoholic fatty liver to nonalcoholic steatohepatitis,and can even lead to cirrhosis and liver cancer.However,a well-established treatment for NAFLD has yet to be identified.Exosomes have become an ideal drug delivery tool because of their high transmissibility,low immunogenicity,easy accessibility and targeting.Exosomes with specific modifications,known as engineered exosomes,have the potential to treat a variety of diseases.Here,we review the treatment of NAFLD with engineered exosomes and the potential use of exosomes as biomarkers and therapeutic targets for NAFLD. 展开更多
关键词 Nonalcoholic fatty liver disease Nonalcoholic steatohepatitis EXOSOME Engineered exosome Targeted therapy
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Volatile threshold switching memristor:An emerging enabler in the AIoT era 被引量:1
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作者 Wenbin Zuo Qihang Zhu +5 位作者 Yuyang Fu Yu Zhang Tianqing Wan Yi Li ming xu Xiangshui Miao 《Journal of Semiconductors》 EI CAS CSCD 2023年第5期122-144,共23页
With rapid advancement and deep integration of artificial intelligence and the internet-of-things,artificial intelligence of things has emerged as a promising technology changing people’s daily life.Massive growth of... With rapid advancement and deep integration of artificial intelligence and the internet-of-things,artificial intelligence of things has emerged as a promising technology changing people’s daily life.Massive growth of data generated from the devices challenges the AIoT systems from information collection,storage,processing and communication.In the review,we introduce volatile threshold switching memristors,which can be roughly classified into three types:metallic conductive filament-based TS devices,amorphous chalcogenide-based ovonic threshold switching devices,and metal-insulator transition based TS devices.They play important roles in high-density storage,energy efficient computing and hardware security for AIoT systems.Firstly,a brief introduction is exhibited to describe the categories(materials and characteristics)of volatile TS devices.And then,switching mechanisms of the three types of TS devices are discussed and systematically summarized.After that,attention is focused on the applications in 3D cross-point memory technology with high storage-density,efficient neuromorphic computing,hardware security(true random number generators and physical unclonable functions),and others(steep subthreshold slope transistor,logic devices,etc.).Finally,the major challenges and future outlook of volatile threshold switching memristors are presented. 展开更多
关键词 AIoT threshold switching MEMRISTOR SELECTOR neuromorphic computing hardware security
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Efficient light-driven reductive amination of furfural to furfurylamine over ruthenium-cluster catalyst 被引量:1
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作者 Zhen xue Shasha Wu +7 位作者 Yujing Fu Lan Luo Min Li Zhenhua Li mingfei Shao Lirong Zheng ming xu Haohong Duan 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第1期239-248,I0007,共11页
Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reaction... Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reactions.Herein,the ultrasmall Ru nanoclusters(~0.9 nm)were successfully fabricated over P25 support with positive charged Ru^(δ+)species at the interface.A new route was developed to achieve the furfural(FAL)to furfurylamine(FAM)by coupling the light-driven reductive amination and hydrogen transfer of ethanol over this type catalyst.Strikingly,the photocatalytic activity and selectivity are strongly dependent on the particle size and electronic structure of Ruthenium.The Ru^(δ+)species at the interface promote the formation of active imine intermediates;moreover,the Ru nanoclusters facilitate the separation efficiency of electrons and holes as well as accelerate the further hydrogenation of imine intermediates to product primary amines.In contrast Ru particles in larger nanometer size facilitate the formation of the furfuryl alcohol and excessive hydrogenation products.In addition,the coupling byproducts can be effectively inhibited via the construction of sub-nanocluster.This study offers a new path to produce the primary amines from biomass-derived carbonyl compounds over hybrid semiconductor/metal-clusters photocatalyst via light-driven tandem catalytic process. 展开更多
关键词 FURFURAL Reductive amination Ru nanoclusters Hydrogen transfer PHOTOCATALYSIS
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Towards Practical Application of Li-S Battery with High Sulfur Loading and Lean Electrolyte:Will Carbon-Based Hosts Win This Race? 被引量:1
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作者 Yi Gong Jing Li +7 位作者 Kai Yang Shaoyin Li ming xu Guangpeng Zhang Yan Shi Qiong Cai Huanxin Li Yunlong Zhao 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第9期384-422,共39页
As the need for high-energy–density batteries continues to grow, lithium-sulfur(Li–S) batteries have become a highly promising next-generation energy solution due to their low cost and exceptional energy density com... As the need for high-energy–density batteries continues to grow, lithium-sulfur(Li–S) batteries have become a highly promising next-generation energy solution due to their low cost and exceptional energy density compared to commercially available Li-ion batteries. Research into carbon-based sulfur hosts for Li–S batteries has been ongoing for over two decades, leading to a significant number of publications and patents.However, the commercialization of Li–S batteries has yet to be realized. This can be attributed, in part, to the instability of the Li metal anode. However, even when considering just the cathode side, there is still no consensus on whether carbon-based hosts will prove to be the best sulfur hosts for the industrialization of Li–S batteries. Recently, there has been controversy surrounding the use of carbon-based materials as the ideal sulfur hosts for practical applications of Li–S batteries under high sulfur loading and lean electrolyte conditions. To address this question, it is important to review the results of research into carbon-based hosts, assess their strengths and weaknesses, and provide a clear perspective. This review systematically evaluates the merits and mechanisms of various strategies for developing carbon-based host materials for high sulfur loading and lean electrolyte conditions. The review covers structural design and functional optimization strategies in detail, providing a comprehensive understanding of the development of sulfur hosts. The review also describes the use of efficient machine learning methods for investigating Li–S batteries. Finally, the outlook section lists and discusses current trends, challenges, and uncertainties surrounding carbon-based hosts, and concludes by presenting our standpoint and perspective on the subject. 展开更多
关键词 Li-S batteries Carbon materials Structural design Functional modification Machine learning
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Colorless to black switching with high contrast ratio via the electrochemical process of a hybrid organic-inorganic perovskite 被引量:1
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作者 ming xu Jianmin Gu +5 位作者 Zixun Fang Yu Li Xing Wang Xiaoyu Zhao Tifeng Jiao Wei Wang 《Carbon Energy》 SCIE EI CAS CSCD 2023年第11期90-100,共11页
Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the t... Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices. 展开更多
关键词 colorless to black switching electrochemical process high integrated contrast ratio hybrid organic-inorganic perovskite switchable devices
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Rational design and low-cost fabrication of multifunctional separators enabling high sulfur utilization in long-life lithium-sulfur batteries 被引量:1
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作者 Xiaoqing Zhang Wei Yuan +7 位作者 Honglin Huang ming xu Yu Chen Bote Zhao Xinrui Ding Shiwei Zhang Yong Tang Longsheng Lu 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2023年第1期266-280,共15页
The lithium-sulfur(Li-S)battery with an ultrahigh theoretical energy density has emerged as a promising rechargeable battery system.However,the practical applications of Li-S batteries are severely plagued by the slug... The lithium-sulfur(Li-S)battery with an ultrahigh theoretical energy density has emerged as a promising rechargeable battery system.However,the practical applications of Li-S batteries are severely plagued by the sluggish reaction kinetics of sulfur species and notorious shuttling of soluble lithium polysulfides(LiPSs)intermediates that result in low sulfur utilization.The introduction of functional layers on separators has been considered as an effective strategy to improve the sulfur utilization in Li-S batteries by achieving effective regulation of LiPSs.Herein,a promising self-assembly strategy is proposed to achieve the low-cost fabrication of hollow and hierarchically porous Fe_(3)O_(4)nanospheres(p-Fe_(3)O_(4)-NSs)assembled by numerous extremely-small primary nanocrystals as building blocks.The rationally-designed p-Fe_(3)O_(4)-NSs are utilized as a multifunctional layer on the separator with highly efficient trapping and conversion features toward LiPSs.Results demonstrate that the nanostructured p-Fe_(3)O_(4)-NSs provide chemical adsorption toward LiPSs and kinetically promote the mutual transformation between LiPSs and Li_(2)S_(2)/Li_(2)S during cycling,thus inhibiting the LiPSs shuttling and boosting the redox reaction kinetics via a chemisorption-catalytic conversion mechanism.The enhanced wettability of the p-Fe_(3)O_(4)-NSs-based separator with the electrolyte enables fast transportation of lithium ions.Benefitting from these alluring properties,the functionalized separator with p-Fe_(3)O_(4)-NSs endows the battery with an admirable rate performance of 877 mAh g^(−1)at 2 C,an ultra-durable cycling performance of up to 2176 cycles at 1 C,and a promising areal capacity of 4.55 mAh cm^(−2)under high-sulfur-loading and lean-electrolyte conditions(4.29 mg cm^(−2),electrolyte/ratio:8μl mg^(−1)).This study will offer fresh insights on the rational design and low-cost fabrication of multifunctional separator to strengthen electrochemical reaction kinetics by regulating LiPSs conversion for developing efficient and long-life Li-S batteries. 展开更多
关键词 lithium-sulfur battery multifunctional separator low-cost fabrication chemisorption-catalytic conversion mechanism hierarchically porous Fe_(3)O_(4)nanospheres
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Effects of macrosegregation on mechanical and tribological properties of squeeze casting immiscible bearing alloys
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作者 ming xu Yan-guo Yin +2 位作者 Cong-min Li Guo-tao Zhang Cong-chong Duan 《China Foundry》 SCIE CAS CSCD 2023年第5期443-451,共9页
The macrosegregation behaviors of Al-Sn-Cu ternary immiscible alloy castings and their effects on mechanical and tribological properties were investigated.The results demonstrate that Sn and Cu segregate in the castin... The macrosegregation behaviors of Al-Sn-Cu ternary immiscible alloy castings and their effects on mechanical and tribological properties were investigated.The results demonstrate that Sn and Cu segregate in the casting simultaneously,and the mass fraction of the two elements has a"U"shaped distribution.Significantly,positive and negative segregation occur in the casting,with positive segregation appearing on the top and lower surfaces and negative segregation on the remaining surfaces,with the 1/2 surface(hot node location)having the highest degree of negative segregation.Furthermore,the results of Vickers hardness,tensile strength,and elongation show that Sn and Cu cooperatively affect the mechanical properties of castings.The higher the mass fraction of Sn and Cu elements,the higher the hardness,the greater the tensile strength,and the better the elongation.The findings of the step-by-step loading tests demonstrate that the segregation of Sn and Cu significantly impacts the tribological characteristics of the castings.The higher the mass fraction of Sn and Cu on the sample surface,the better the tribological characteristics. 展开更多
关键词 squeeze casting Al-Sn-Cu MACROSEGREGATION mechanical properties tribological property
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Carcinosarcoma of common bile duct:A case report
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作者 Yao Yao Hong-Gang Xiang +2 位作者 Lei Jin ming xu Shu-Yan Mao 《World Journal of Gastrointestinal Oncology》 SCIE 2023年第3期562-570,共9页
BACKGROUND Carcinosarcomas of the common bile duct(CBD)are an extremely rare finding in the clinical setting.Based on a review of 12 literatures,3 cases had the imaging features of ossification.Carcinosarcomas are pro... BACKGROUND Carcinosarcomas of the common bile duct(CBD)are an extremely rare finding in the clinical setting.Based on a review of 12 literatures,3 cases had the imaging features of ossification.Carcinosarcomas are prone to distant metastasis,as they possess clinical features of both carcinoma and sarcoma,and generally have with a poor prognosis.Due to the small number of cases reported,clinical experience in the diagnosis and treatment of the disease is lacking.CASE SUMMARY The patient was a 75-year-old woman who had experienced recurrent chills with nausea and vomiting for 3 mo.Computed tomography,magnetic resonance imaging,endoscopic ultrasonography and endoscopic retrograde cholangiopancreatography led to the diagnosis of malignant tumor of the CBD.The patient ultimately underwent cholecystectomy,CBD resection,and choledochojejunostomy.Postoperative pathological examination revealed carcinosarcoma of the CBD,and the latest follow-up showed that the patient is recovering well.Based on previous case reports,some carcinosarcoma has ossification characteristics in imaging.If it is misdiagnosed as biliary calculi,the use of laser lithotripsy in surgery may lead to tumor diffusion.Choledochoscopy and narrow band staining of mucosa are very important for diagnosis.CONCLUSION We herein present a rare case of carcinosarcomas of the CBD,we found the tumours may have imaging features of polypoid growth and ossification only when the sarcomal components are bone differentiation,while show soft tissue shadow when non bone differentiation.Confirmation of diagnosis depends greatly upon postoperative pathological examination and the adjuvant treatment has not been established,which leads to the poor prognosis. 展开更多
关键词 CARCINOSARCOMA Sarcocarcinoma Sarcomatoid carcinoma Extrahepatic bile duct tumor Common bile duct tumor Case report
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模拟直流电机调速特性的双向DC/DC变换器虚拟直流电机控制策略 被引量:7
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作者 支娜 明旭 +2 位作者 张林杰 张辉 张伟亮 《电力自动化设备》 EI CSCD 北大核心 2022年第12期115-121,共7页
传统虚拟直流电机VDCM(Virtual DC Machine)控制策略未考虑直流电机转速动态调节问题,不能够在直流母线电压变化瞬间起调节作用。对此,提出一种模拟直流电机闭环调速的储能侧双向DC/DC变换器新型VDCM控制策略。对直流电机与双向DC/DC变... 传统虚拟直流电机VDCM(Virtual DC Machine)控制策略未考虑直流电机转速动态调节问题,不能够在直流母线电压变化瞬间起调节作用。对此,提出一种模拟直流电机闭环调速的储能侧双向DC/DC变换器新型VDCM控制策略。对直流电机与双向DC/DC变换器在数学模型和控制策略上进行联系等效与差异剖析,模拟直流电机定转子绕组间的电磁感应作用,将直流电机动态数学模型嵌入P-U下垂控制中,使其兼备电压动态调节能力和惯性阻尼特性。对采用新型VDCM控制策略前、后的作用效果进行对比,仿真和实验结果表明该控制策略能够在提升母线电压动态调节特性的同时,增强惯性调节和阻尼效果,在负载切换或分布式发电单元输出功率波动时维持直流微电网稳定运行。 展开更多
关键词 直流微电网 双向DC/DC变换器 下垂控制 VDCM控制
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