检索结果-南通市图书馆

维普期刊数据库

The Combined Effect of Spin-Transfer Torque and Voltage-Controlled Strain Gradient on Magnetic Domain-Wall Dynamics:Toward Tunable Spintronic Neuron

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2024年第5期41卷 120-137页

作者：郁国良何鑫岩施胜宾邱阳朱明敏王嘉维李燕李元勋王杰周浩淼 college of Information engineering China Jiliang UniversityHangzhou 310018China The Key Laboratory of Electromagnetic Wave Information technology and metrology of Zhejiang Province Hangzhou 310018China Department of engineering Mechanics Zhejiang UniversityHangzhou 310027China School of Electronic Science and engineering University of Electronic Science and Technology of ChinaChengdu 611731China

Magnetic domain wall(DW), as one of the promising information carriers in spintronic devices, have been widely investigated owing to its nonlinear dynamics and tunable properties. Here, we theoretically and numerically demonstrate the DW dynamics driven by the synergistic interaction between current-induced spin-transfer torque(STT) and voltage-controlled strain gradient(VCSG) in multiferroic heterostructures. Through electromechanical and micromagnetic simulations, we show that a desirable strain gradient can be created and it further modulates the equilibrium position and velocity of the current-driven DW motion. Meanwhile, an analytical Thiele's model is developed to describe the steady motion of DW and the analytical results are quite consistent with the simulation data. Finally, we find that this combination effect can be leveraged to design DW-based biological neurons where the synergistic interaction between STT and VCSG-driven DW motion as integrating and leaking motivates mimicking leaky-integrate-and-fire(LIF) and self-reset function. Importantly, the firing response of the LIF neuron can be efficiently modulated, facilitating the exploration of tunable activation function generators, which can further help improve the computational capability of the neuromorphic system.

关键词： tunable synergistic integrating

维普期刊数据库

Performance Study of MIMO-OSTBC Parallel Relay FSO System Based on GFDM

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第2期33卷 564-572页

作者： Rui ZHOU Yong WANG Yi WANG Key Laboratory of Electromagnetic Wave Information technology and metrology of Zhejiang Province College of Information Engineering China Jiliang University State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering Hohai University

This paper investigates the performance of a new generalized frequency division multiplexing(GFDM)parallel relay free space optical(FSO) communication system using multi-input multi-output(MIMO) orthogonal space-time block codes(OSTBC) scheme. Under the M distribution atmospheric turbulence, taking into account the triple effects of irradiance, pointing errors and path loss, the mathematical expression of system symbol error rate is derived with the help of Meijer G-function. The symbol error performance of GFDM is compared with on-off keying,Gaussian minimum shift keying, polarization shift keying and orthogonal frequency division multiplexing(OFDM)modulation methods. The effects of the MIMO-OSTBC parallel relay scheme on the GFDM system including filter roll down coefficient, the number of transmitting and receiving antennas, the number of relays, normalized beamwidth and jitter variance are analyzed, and the numerical results are verified by Monte Carlo simulation. This work provides a good foundation for engineering applications.

关键词： Monte Carlo methods Transmitting antennas Symbols Receiving antennas Modulation Jitter Transceivers

Time-dependent model for two-phase flow in ultra-high water-cut reservoirs: Time-varying permeability and relative permeability

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第4期21卷 2536-2553页

作者： Shao-Chun Wang Na Zhang Zhi-Hao Tang Xue-Fei Zou Qian Sun Wei Liu college of Energy Resources Chengdu University of Technology college of Petroleum engineering Shandong Institute of Petroleum and Chemical Technology

For the ultra-high water-cut reservoirs, after long-term water injection exploitation, the physical properties of the reservoir change and the heterogeneity of the reservoir becomes increasingly severe, which further aggravates the spatial difference of the flow field. In this study, the displacement experiments were employed to investigate the variations in core permeability, porosity, and relative permeability after a large amount of water injection. A relative permeability endpoint model was proposed by utilizing the alternating conditional expectation(ACE) transformation to describe the variation in relative permeability based on the experimental data. Based on the time dependent models for permeability and relative permeability, the traditional oil-water two-phase model was improved and discretized using the mimetic finite difference method(MFD). The two cases were launched to confirm the validation of the proposed model. The impact of time-varying physical features on reservoir production performance was studied in a real water flooding reservoir. The experimental results indicate that the overall relative permeability curve shifts to the right as water injection increases. This shift corresponds to a transition towards a more hydrophilic wettability and a decrease in residual oil saturation. The endpoint model demonstrates excellent accuracy and can be applied to time-varying simulations of reservoir physics. The impact of variations in permeability and relative permeability on the reservoir production performance yields two distinct outcomes. The time-varying permeability of the reservoir results in intensified water channeling and poor development effects. On the other hand, the time-varying relative permeability enhances the oil phase seepage capacity, facilitating oil displacement. The comprehensive time-varying behavior is the result of the combined influence of these two parameters, which closely resemble the actual conditions observed in oil field expl

关键词： Mimetic finite difference Water flooding reservoir Time-varying physical properties Numerical simulation

Promoting electrocatalytic nitrogen reduction to ammonia via dopant boron on two-dimensional materials

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第10期43卷 5117-5125页

作者： Ya-Hui Cui Wen-Cheng Ouyang Ai-Jun Gao Chang-Yuan Yu Li-Peng Zhang State Key Laboratory of Organic-Inorganic Composites College of Chemical EngineeringBeijing University of Chemical Technology college of Materials Science and engineering Beijing University of Chemical Technology college of Life Science and technology Beijing University of Chemical Technology

Electrocatalytic nitrogen reduction reaction(NRR) is a key process for producing energy efficient and environment friendly ammonia. Boron-doped two-dimensional materials are highly promising as NRR ***, the interaction between doped boron and matrix materials on NRR catalytic performance is still unclear,which is limiting the development of catalysts containing boron for NRR. Here, NRR on different boron-doped twodimensional(2D) materials was explored by first principle theory. It is found that adsorption energy of intermediate*NNH(E*NNH) can be used as a descriptor to characterize the catalytic activity for NRR. Boron-adsorbed black phosphorus(B-BP) is demonstrated showing excellent NRR catalytic activity and suppressing hydrogen evolution reaction. It is disclosed that the excellent catalytic performance of boron-doped structures comes from a proper quantitatively electron transfer(0.8e) between nitrogen in*NNH and the active site boron atom. This work not only established a descriptor for NRR catalytic activity on B-doped 2D materials, but also screened out a potential NRR catalyst. More importantly, the intrinsic reason and mechanism of high catalytic activity of boron-doped structures were proposed. This work provides a design principle for exploring high-performance NRR electrocatalysts containing boron.

关键词： Boron-doped two-dimensional materials Density functional theory Descriptor Electrocatalytic nitrogen reduction reaction

Viscoacoustic generalized screen propagator in constant-Q model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第4期21卷 2356-2369页

作者： Zhong-Kui Dai Jia-Chun You Xing-Guo Huang Wei Liu college of Geophysics Chengdu University of Technology college of Instrumentation and Electrical engineering Jilin University

When seismic waves propagate through the geological formation, there is a significant loss of energy and a decrease in imaging resolution, because of the viscoacoustic properties of subsurface medium. This profoundly impacts seismic wavefield propagation, imaging and interpretation. To accurately image the true structure of subsurface medium, the consensus among geophysicists is to no longer treat subsurface medium as ideal homogeneous medium, but rather to incorporate the viscoacoustic properties of subsurface medium. Based on the generalized screen propagator using conventional acoustic wave equation(acoustic GSP), our developed method introduces viscoacoustic compensation strategy, and derives a one-way wave generalized screen propagator based on time-fractional viscoacoustic wave equation(viscoacoustic GSP). In numerical experiments, we conducted tests on two-dimensional multi-layer model and the Marmousi model. When comparing with the acoustic GSP using the acoustic data, we found that the imaging results of the viscoacoustic GSP using the viscoacoustic data showed a significant attenuation compensation effect, and achieved imaging results for both algorithms were essentially consistent. However, the imaging results of acoustic GSP using viscoacoustic data showed significant attenuation effects, especially for deep subsurface imaging. This indicates that we have proposed an effective method to compensate the attenuated seismic wavefield. Our application on a set of real seismic data demonstrated that the imaging performance of our proposed method in local areas surpassed that of the conventional acoustic GSP. This suggests that our proposed method holds practical value and can more accurately image real subsurface structures while enhancing imaging resolution compared with the conventional acoustic GSP. Finally, with respect to computational efficiency, we gathered statistics on running time to compare our proposed method with conventional Q-RTM, and it is evid

关键词： One-way wave equation Viscoacoustic wave equation Generalized screen propagator Attenuation and dispersion effects

Carbon felt electrode coated with WS2 enables a high-performance polysulfide/ferricyanide flow battery

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第10期43卷 5039-5047页

作者： Liang-Yu Li Su Yan Ying-Jia Huang Fang-Fang Zhong Jin-Chao Cao Mei Ding Chuan-Kun Jia college of Materials Science and engineering Changsha University of Science and Technology Institute of Energy Storage technology College of Energy and Power EngineeringChangsha University of Science and Technology Binzhou Institute of technology Weiqiao-UCAS Science and Technology Park

Polysulfide/ferricyanide flow batteries （S/Fe RFBs）,with the advantages of abundant earth reservation low cost,high safety,and environmental friendliness,have attracted significant interest and demonstrated noteworthy potential for practical ***,the battery performance,including the energy efficiency （EE）,voltage efficiency （VE）,and power density of the S/Fe RFBs remains low owing to the slow redox kinetics of polysulfide *** address these concerns,WS2was selected as the booster and deposited on a commercial carbon felt electrode （WS2–CF） to stimulate the redox reactions of polysulfide *** better hydrophilicity and smaller charge-transfer resistance,WS2–CF exhibits enhanced electrochemical activity toward polysulfide redox ***,the battery performance of S/Fe RFB with WS2–CF as the anode has been improved,with EE of 84%,VE of 84%,and a peak power density of 175.7 mW·cm-2,which are all higher than the cell only with the bare carbon felt （CF） as electrodes (76%,77% and 155.8 mW·cm-2,respectively).Furthermore,the cycling life of the S/Fe RFB with WS2–CF has been prolonged to 2200 cycles with a capacity retention of 96% a 40 mA·cm-2because of the good stability of WS2–CF as the ***,under the same conditions,the S/Fe RFB without WS2–CF terminated after 1500 cycles with a fast capacity *** successful utilization of WS2as a booster on an electrode provides an efficient strategy for obtaining advanced S/Fe RFBs for practical applications.

关键词： Carbon felt Energy storage Polysulfide/ferricyanide flow battery Tungsten disulfide

Artificial neural network-based method for discriminating Compton scattering events in high-purity germaniumγ-ray spectrometer

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第2期35卷 64-84页

作者： Chun-Di Fan Guo-Qiang Zeng Hao-Wen Deng Lei Yan Jian Yang Chuan-Hao Hu Song Qing Yang Hou college of Nuclear technology and Automation engineering Chengdu University of TechnologyChengdu 610059China

To detect radioactive substances with low activity levels,an anticoincidence detector and a high-purity germanium(HPGe)detector are typically used simultaneously to suppress Compton scattering background,thereby resulting in an extremely low detection limit and improving the measurement ***,the complex and expensive hardware required does not facilitate the application or promotion of this ***,a method is proposed in this study to discriminate the digital waveform of pulse signals output using an HPGe detector,whereby Compton scattering background is suppressed and a low minimum detectable activity(MDA)is achieved without using an expensive and complex anticoincidence detector and *** electric-field-strength and energy-deposition distributions of the detector are simulated to determine the relationship between pulse shape and energy-deposition location,as well as the characteristics of energy-deposition distributions for fulland partial-energy deposition *** relationship is used to develop a pulse-shape-discrimination algorithm based on an artificial neural network for pulse-feature *** accurately determine the relationship between the deposited energy of gamma(γ)rays in the detector and the deposition location,we extract four shape parameters from the pulse signals output by the *** learning is used to input the four shape parameters into the ***,the pulse signals are identified and classified to discriminate between partial-and full-energy deposition *** partial-energy deposition events are removed to suppress Compton *** proposed method effectively decreases the MDA of an HPGeγ-energy dispersive *** results show that the Compton suppression factors for energy spectra obtained from measurements on ^(152)Eu,^(137)Cs,and ^(60)Co radioactive sources are 1.13(344 keV),1.11(662 keV),and 1.08(1332 keV),respectively,and that the corresponding MDAs are 1.4%,5.

关键词： High-purity germaniumγ-ray spectrometer Pulse-shape discrimination Compton scattering Artificial neural network Minimum detectable activity

维普期刊数据库

Research on Performance Optimization of Spark Distributed Computing Platform

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第5期79卷 2833-2850页

作者： Qinlu He Fan Zhang Genqing Bian Weiqi Zhang Zhen Li School of Information and Control engineering Xi’an University of Architecture and TechnologyXi’an710054China Shaanxi Institute of metrology Science Xi’an710043China

Spark,a distributed computing platform,has rapidly developed in the field of big *** in-memory computing feature reduces disk read overhead and shortens data processing time,making it have broad application prospects in large-scale computing applications such as machine learning and image ***,the performance of the Spark platform still needs to be *** a large number of tasks are processed simultaneously,Spark’s cache replacementmechanismcannot identify high-value data partitions,resulting inmemory resources not being fully utilized and affecting the performance of the Spark *** address the problem that Spark’s default cache replacement algorithm cannot accurately evaluate high-value data partitions,firstly the weight influence factors of data partitions are modeled and ***,based on this weighted model,a cache replacement algorithm based on dynamic weighted data value is proposed,which takes into account hit rate and data *** integration and usage strategies are implemented based on LRU(LeastRecentlyUsed).Theweight update algorithm updates the weight value when the data partition information changes,accurately measuring the importance of the partition in the current job;the cache removal algorithm clears partitions without useful values in the cache to releasememory resources;the weight replacement algorithm combines partition weights and partition information to replace RDD partitions when memory remaining space is ***,by setting up a Spark cluster environment,the algorithm proposed in this paper is experimentally *** have shown that this algorithmcan effectively improve cache hit rate,enhance the performance of the platform,and reduce job execution time by 7.61%compared to existing improved algorithms.

关键词： Spark memory optimization memory replacement strategy

Enhancing the Goos-Hänchen shift based on quasi-bound states in the continuum through material asymmetric dielectric compound gratings

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第3期33卷 393-400页

作者：江孝伟方彬占春连 college of Optical and Electronic technology China Jiliang UniversityHangzhou 310018China college of Information engineering Quzhou College of TechnologyQuzhou 324000China

Quasi-bound state in the continuum(QBIC)resonance is gradually attracting attention and being applied in Goos-Hänchen(GH)shift enhancement due to its high quality(Q)factor and superior optical ***,symmetry-protected QBIC resonance is often achieved by breaking the geometric symmetry,but few cases are achieved by breaking the material *** paper proposes a dielectric compound grating to achieve a high Q factor and high-reflection symmetry-protectede QBIC resonance based on material *** calculations show that the symmetry-protected QBIC resonance achieved by material asymmetry can significantly increase the GH shift up to-980 times the resonance wavelength,and the maximum GH shift is located at the reflection peak with unity *** paper provides a theoretical basis for designing and fabricating high-performance GH shift tunable metasurfaces/dielectric gratings in the future.

关键词： bound state in the continuum Goos-Hänchen shift dielectric compound grating material asymmetry