检索结果-南通市图书馆

Chinese Journal of Electronics 2024年第3期33卷 814-822页

作者： Junqi LIU Tao WEN Guo XIE yuan cao Clive Roberts Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing Xi'an University of Technology The School of Electronic and Information Engineering Beijing Jiaotong University Birmingham Centre for Railway Research and Education University of Birmingham

The fault diagnosis of railway point machines(RPMs) has attracted the attention of engineers and *** have studies considered diverse noises along the *** fulfill this aspect,a multi-time-scale variational mode decomposition(MTSVMD) is proposed in this paper to realize the accurate and robust fault diagnosis of RPMs under multiple *** decomposes condition monitoring signals after coarse-grained processing in varying *** this manner,the information contained in the signal components at multiple time scales can construct a more abundant feature space than at a single *** the experimental validation,a random position,random type,random number,and random length(4R) noise-adding algorithm helps to verify the robustness of the *** adequate experimental results demoristrate the superiority of the proposed MTSVMD-based fault diagnosis.

关键词： Fault diagnosis Condition monitoring Noise Signal processing algorithms Aerospace electronics Rail transportation Robustness

Advanced 3D ordered electrodes for PEMFC applications: From structural features and fabrication methods to the controllable design of catalyst layers

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Green Energy & Environment 2024年第9期9卷 1336-1365页

作者： Kaili Wang Tingting Zhou Zhen cao Zhimin yuan Hongyan He Maohong Fan Zaiyong Jiang School of Chemistry & Chemical Engineering and Environmental Engineering Weifang University Beijing Key Laboratory of Ionic Liquids Clean Process State Key Laboratory of Multiphase Complex Systems CAS Key Laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences College Engineering and Physical Sciences and School of Energy Resources University of Wyoming

The catalyst layers(CLs) electrode is the key component of the membrane electrode assembly(MEA) in proton exchange membrane fuel cells(PEMFCs). Conventional electrodes for PEMFCs are composed of carbon-supported, ionomer, and Pt nanoparticles, all immersed together and sprayed with a micron-level thickness of CLs. They have a performance trade-off where increasing the Pt loading leads to higher performance of abundant triple-phase boundary areas but increases the electrode cost. Major challenges must be overcome before realizing its wide commercialization. Literature research revealed that it is impossible to achieve performance and durability targets with only high-performance catalysts, so the controllable design of CLs architecture in MEAs for PEMFCs must now be the top priority to meet industry goals. From this perspective, a 3D ordered electrode circumvents this issue with a support-free architecture and ultrathin thickness while reducing noble metal Pt loadings. Herein, we discuss the motivation in-depth and summarize the necessary CLs structural features for designing ultralow Pt loading electrodes. Critical issues that remain in progress for 3D ordered CLs must be studied and characterized. Furthermore, approaches for 3D ordered CLs architecture electrode development, involving material design, structure optimization, preparation technology, and characterization techniques, are summarized and are expected to be next-generation CLs for PEMFCs. Finally, the review concludes with perspectives on possible research directions of CL architecture to address the significant challenges in the future.

关键词： PEMFC 3D ordered electrode Structural features Preparation technology Ultralow Pt loading

Selective leaching of calcium from mechanically activated mixed rare earth concentrate

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第6期42卷 1149-1156,I0006页

作者： Jiang Liu Bingxue Chen yuanqi Feng Yijun cao Yukun Huang yuan Shi Meng Li Zhongyuan Critical Metals Laboratory School of Chemical EngineeringZhengzhou UniversityZhengzhou450001China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou730050China

The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth *** an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by applying selective mechanical activation was ***,regarding the key minerals affecting the leaching selectivity of Ca to REs,the differences in the mechanical activation behaviors of CaF_(2) and REFCO_(3) were studied,and we find that the lattice strain of CaF_(2) increases from 0.21%to 0.42%,whereas that of REFCO_(3) increases from 0.31%to 0.40%.Notably,CaF_(2) demonstrates a larger lattice strain than REFCO_(3),indicating greater mechanical activation energy storage and higher leaching ***,the HCl leaching process was studied.A significant leaching selectivity of Ca to REs,from 21.6 to 35.1,is achieved through mechanical *** Ca leaching rate reaches 80.7%when the RE loss is 2.3%in the activated *** study provides an novel approach for achieving selective extraction of specific components via mechanical activation pretreatment.

关键词： Mixed rare earth concentrate Pre-decalcification Selective mechanical activation Selective leaching

Variational quantum algorithms for scanning the complex spectrum of non-Hermitian systems

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第4期19卷 275-285页

作者： xu-Dan Xie Zheng-yuan xue Dan-Bo Zhang Key Laboratory of Atomic and Subatomic Structure and Quantum Control(Ministry of Education) Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matterand School of PhysicsSouth China Normal UniversityGuangzhou 510006China Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials Guangdong–Hong Kong Joint Laboratory of Quantum Matterand Frontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China

Solving non-Hermitian quantum many-body systems on a quantum computer by minimizing the variational energy is challenging as the energy can be ***,we propose a variational quantum algorithm for solving the non-Hermitian Hamiltonian by minimizing a type of energy variance,where zero variance can naturally determine the eigenvalues and the associated left and right ***,the energy is set as a parameter in the cost function and can be tuned to scan the whole spectrum efficiently by using a two-step optimization *** numerical simulations,we demonstrate the algorithm for preparing the left and right eigenstates,verifying the biorthogonal relations,as well as evaluating the *** also investigate the impact of quantum noise on our algorithm and show that its performance can be largely improved using error mitigation ***,our work suggests an avenue for solving non-Hermitian quantum many-body systems with variational quantum algorithms on near-term noisy quantum computers.

关键词： quantum algorithm non-Hermitian physics quantum manybody systems

Detection Algorithm of Laboratory Personnel Irregularities Based on Improved YOLOv7

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第2期78卷 2741-2765页

作者： Yongliang Yang Linghua xu Maolin Luo Xiao Wang Min cao School of Electrical Engineering Guizhou UniversityGuiyang550025China

Due to the complex environment of the university laboratory,personnel flow intensive,personnel irregular behavior is easy to cause security *** using mainstream detection algorithms suffers from low detection accuracy and slow ***,the current management of personnel behavior mainly relies on institutional constraints,education and training,on-site supervision,etc.,which is time-consuming and *** the above situation,this paper proposes an improved You Only Look Once version 7(YOLOv7)to achieve the purpose of quickly detecting irregular behaviors of laboratory personnel while ensuring high detection ***,to better capture the shape features of the target,deformable convolutional networks(DCN)is used in the backbone part of the model to replace the traditional convolution to improve the detection accuracy and ***,to enhance the extraction of important features and suppress useless features,this paper proposes a new convolutional block attention module_efficient channel attention(CBAM_E)for embedding the neck network to improve the model’s ability to extract features from complex ***,to reduce the influence of angle factor and bounding box regression accuracy,this paper proposes a newα-SCYLLA intersection over union(α-SIoU)instead of the complete intersection over union(CIoU),which improves the regression accuracy while increasing the convergence *** experiments on public and homemade datasets show that the improved algorithm outperforms the original algorithm in all evaluation indexes,with an increase of 2.92%in the precision rate,4.14%in the recall rate,0.0356 in the weighted harmonic mean,3.60%in the mAP@0.5 value,and a reduction in the number of parameters and *** with the mainstream algorithm,the improved algorithm has higher detection accuracy,faster convergence speed,and better actual recognition effect,indicating the effectiveness of the improved algorithm in this p

关键词： University laboratory personnel behavior YOLOv7 deformable convolutional networks attention module intersection over union

Effects of diamond particle size on microstructure and properties of diamond/Al-12Si composites prepared by vacuum-assisted pressure infiltration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2024年第4期21卷 360-368页

作者： Jia-ping Fu Can-xu Zhou Guo-fa Mi yuan Liu School of Materials Science and Engineering Henan Polytechnic UniversityJiaozuo 454100HenanChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

Diamond/aluminium composites have attracted attention in the field of thermal management of electronic packaging for their excellent *** order to solve the interfacial problem between diamond and aluminium,a novel process combining pressure infiltration with vacuum-assisted technology was proposed to prepare diamond/aluminum *** effect of diamond particle size on the microstructure and properties of the diamond/Al-12Si composites was *** results show that the diamond/Al-12Si composites exhibit high relative density and a uniform *** thermal conductivity and coefficient of thermal expansion increase with increasing particle size,while the bending strength exhibits the opposite *** the average diamond particle size increases from 45μm to 425μm,the thermal conductivity of the composites increases from 455 W·m^(-1)·K^(-1)to 713 W·m^(-1)·K^(-1)and the coefficient of thermal expansion increases from 4.97×10^(-6)K^(-1)to 6.72×10^(-6)K^(-1),while the bending strength decreases from 353 MPa to 246 *** research demonstrates that high-quality composites can be prepared by the vacuum-assisted pressure infiltration process and the thermal conductivity of the composites can be effectively improved by increasing the diamond particle size.

关键词： diamond/aluminum composites thermal conductivity electronic packaging vacuum-assisted pressure infiltration

Applying deep learning technique to chiral magnetic wave search

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第8期48卷 170-176页

作者： yuan-Sheng Zhao xu-Guang Huang Physics Department and Center for Particle Physics and Field Theory Fudan UniversityShanghai 200433China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics National Natural Science Foundation of China and Fudan UniversityShanghai 200438China

The chiral magnetic wave(CMW)is a collective mode in quark-gluon plasma originated from the chiral magnetic effect(CME)and chiral separation *** detection in heavy-ion collisions is challenging owing to significant background ***[*** et al.,***.C 106,L051901(2022)],we constructed a neural network that accurately identifies the CME-related signal from the final-state pion *** this study,we have generalized this neural network to the case of CMW *** show that,after an updated training,the neural network effectively recognizes the CMW-related ***,we have assessed the performance of the neural network in comparison with other known methods for CMW search.

关键词： deep learning chiral magnetic wave relativistic heavy-ion collisions

Mn incorporated RuO_(2) nanocrystals as an efficient and stable bifunctional electrocatalyst for oxygen evolution reaction and hydrogen evolution reaction in acid and alkaline

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第10期35卷 194-200页

作者： Jing cao Dezheng Zhang Bianqing Ren Ping Song Weilin xu State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China Hefei 230026China

The development of efficient and stable bifunctional overall water-splitting is a crucial goal for clean and renewable energy,which is a challenging ***,we report an Mn-incorporated RuO_(2)(MnRuO_(2))catalyst for highly efficient electrocatalytic oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)in acid and alkaline *** from a more electrochemical active area with the incorporation of Mn,the Mn-RuO_(2)required an overpotential of 200 mV to attain a current density of 10 mA/cm^(2)for OER in *** result indicates that the doping of Mn into RuO_(2)can enhance the OER *** acidic overall water-splitting electrolyzer with good stability constructed by bifunctional Mn-RuO_(2)only requires a cell voltage of 1.50 V to afford 10 m A/cm^(2)and can operate stably for 50 h at50 mA/cm^(2),which is better than the state-of-the-art Ru-based ***,the Mn-Ru O_(2)exhibits excellent HER and OER activity in alkaline media,and it shows superior activity and durability for overall water-splitting,only needing a cell voltage of 1.49 V to attain 10 m A/cm^(2).The present work provides an efficient approach to designing and constructing efficient Ru-based electrocatalysts for overall water-splitting.

关键词： RuO_(2)-based solid solution electrocatalysts Oxygenevolution reaction Hydrogen evolution reaction Overall watersplitting Acid andalkaline

Electrostatic generator enhancements for powering IoT nodes via efficient energy management

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2024年第2期10卷 143-152页

作者： Zibo Wu Zeyuan cao Junchi Teng Rong Ding Jiani xu Xiongying Ye State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua University100084BeijingChina

Electrostatic generators show great potential for powering widely distributed electronic devices in Internet of Things(IoT)***,a critical issue limiting such generators is their high impedance mismatch when coupled to electronics,which results in very low energy utilization ***,we present a high-performance energy management unit(EMU)based on a spark-switch tube and a buck converter with an RF *** optimizing the elements and parameters of the EMU,a maximum direct current output power of 79.2 mW m^(-2)rps^(-1)was reached for a rotary electret generator with the EMU,achieving 1.2 times greater power output than without the ***,the maximum power of the contact-separated triboelectric nanogenerator with an EMU is 1.5 times that without the *** excellent performance is attributed to the various optimizations,including utilizing an ultralow-loss spark-switch tube with a proper breakdown voltage,adding a matched input capacitor to enhance available charge,and incorporating an RF inductor to facilitate the high-speed energy transfer *** on this extremely efficient EMU,a compact self-powered wireless temperature sensor node was demonstrated to acquire and transmit data every 3.5 s under a slight wind speed of 0.5 m/*** work greatly promotes the utilization of electrostatic nanogenerators in practical applications,particularly in IoT nodes.

关键词： IoT power generator

Enhanced Flexoelectricity in Barium Titanate-Cellulose Composite Thin Films

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2024年第4期37卷 521-527页

作者： Wensi Xing Hongyu cao Xin Zhang xu Liang Jianwei Song Shengping Shen Chemomechanics and Intelligent Media Laboratory State Key Laboratory for Strength and Vibration of Mechanical StructuresSchool of Aerospace EngineeringXi’an Jiaotong UniversityXi’an710049China

Biopolymers,the potential flexoelectric materials,are environment-friendly,degradable,lightweight,cost-effective,and possess remarkable processing properties catering to the requirements of advanced ***,the flexoelectric coefficient of biopolymers is normally much weaker than that of ceramic materials,limiting their potential applications for designing high-performance green electromechanical coupling *** improve the flexoelectric response in biopolymers,we composited barium titanate(BTO)with 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized cellulose nanofibrils(TOCNF)to enhance the flexoelectric response of *** to the high permittivity and flexoelectric effect of BTO,the relative dielectric constant and flexoelectric coefficient of 33.3 wt%BTO-TOCNF films reached 30.94@1 kHz and 50.05±1.88 nC/m@1 Hz,which were almost 172 times and 27 times higher than those of TOCNF,*** composite thin film contains high dielectric constant and flexoelectric coefficient,as well as excellent *** study provided a straightforward and efficient method for improving the flexoelectric effect of biopolymers,and demonstrated its great potential applications in flexoelectric-based devices.

关键词： Flexoelectricity Cellulose BaTiO_(3) Composite Thin films