期刊文献+
共找到2,348篇文章
< 1 2 118 >
每页显示 20 50 100
Sparse antenna array design methodologies:A review
1
作者 Pan Wu Yan-Hui Liu +1 位作者 Zhi-Qin Zhao Qing-Huo Liu 《Journal of Electronic Science and Technology》 EI CAS CSCD 2024年第3期1-15,共15页
Designing a sparse array with reduced transmit/receive modules(TRMs)is vital for some applications where the antenna system’s size,weight,allowed operating space,and cost are limited.Sparse arrays exhibit distinct ar... Designing a sparse array with reduced transmit/receive modules(TRMs)is vital for some applications where the antenna system’s size,weight,allowed operating space,and cost are limited.Sparse arrays exhibit distinct architectures,roughly classified into three categories:Thinned arrays,nonuniformly spaced arrays,and clustered arrays.While numerous advanced synthesis methods have been presented for the three types of sparse arrays in recent years,a comprehensive review of the latest development in sparse array synthesis is lacking.This work aims to fill this gap by thoroughly summarizing these techniques.The study includes synthesis examples to facilitate a comparative analysis of different techniques in terms of both accuracy and efficiency.Thus,this review is intended to assist researchers and engineers in related fields,offering a clear understanding of the development and distinctions among sparse array synthesis techniques. 展开更多
关键词 Clustered array Nonuniformly spaced array Sparse antenna array Synthesis method Thinned array
下载PDF
Low-Complexity Reconstruction of Covariance Matrix in Hybrid Uniform Circular Array
2
作者 Fu Zihao Liu Yinsheng Duan Hongtao 《China Communications》 SCIE CSCD 2024年第3期66-74,共9页
Spatial covariance matrix(SCM) is essential in many multi-antenna systems such as massive multiple-input multiple-output(MIMO). For multi-antenna systems operating at millimeter-wave bands, hybrid analog-digital struc... Spatial covariance matrix(SCM) is essential in many multi-antenna systems such as massive multiple-input multiple-output(MIMO). For multi-antenna systems operating at millimeter-wave bands, hybrid analog-digital structure has been widely adopted to reduce the cost of radio frequency chains.In this situation, signals received at the antennas are unavailable to the digital receiver, and as a consequence, traditional sample average approach cannot be used for SCM reconstruction in hybrid multi-antenna systems. To address this issue, beam sweeping algorithm(BSA) which can reconstruct the SCM effectively for a hybrid uniform linear array, has been proposed in our previous works. However, direct extension of BSA to a hybrid uniform circular array(UCA)will result in a huge computational burden. To this end, a low-complexity approach is proposed in this paper. By exploiting the symmetry features of SCM for the UCA, the number of unknowns can be reduced significantly and thus the complexity of reconstruction can be saved accordingly. Furthermore, an insightful analysis is also presented in this paper, showing that the reduction of the number of unknowns can also improve the accuracy of the reconstructed SCM. Simulation results are also shown to demonstrate the proposed approach. 展开更多
关键词 hybrid array MILLIMETER-WAVE spatial covariance matrix uniform circular array
下载PDF
New Antenna Array Beamforming Techniques Based on Hybrid Convolution/Genetic Algorithm for 5G and Beyond Communications
3
作者 Shimaa M.Amer Ashraf A.M.Khalaf +3 位作者 Amr H.Hussein Salman A.Alqahtani Mostafa H.Dahshan Hossam M.Kassem 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2749-2767,共19页
Side lobe level reduction(SLL)of antenna arrays significantly enhances the signal-to-interference ratio and improves the quality of service(QOS)in recent and future wireless communication systems starting from 5G up t... Side lobe level reduction(SLL)of antenna arrays significantly enhances the signal-to-interference ratio and improves the quality of service(QOS)in recent and future wireless communication systems starting from 5G up to 7G.Furthermore,it improves the array gain and directivity,increasing the detection range and angular resolution of radar systems.This study proposes two highly efficient SLL reduction techniques.These techniques are based on the hybridization between either the single convolution or the double convolution algorithms and the genetic algorithm(GA)to develop the Conv/GA andDConv/GA,respectively.The convolution process determines the element’s excitations while the GA optimizes the element spacing.For M elements linear antenna array(LAA),the convolution of the excitation coefficients vector by itself provides a new vector of excitations of length N=(2M−1).This new vector is divided into three different sets of excitations including the odd excitations,even excitations,and middle excitations of lengths M,M−1,andM,respectively.When the same element spacing as the original LAA is used,it is noticed that the odd and even excitations provide a much lower SLL than that of the LAA but with amuch wider half-power beamwidth(HPBW).While the middle excitations give the same HPBWas the original LAA with a relatively higher SLL.Tomitigate the increased HPBWof the odd and even excitations,the element spacing is optimized using the GA.Thereby,the synthesized arrays have the same HPBW as the original LAA with a two-fold reduction in the SLL.Furthermore,for extreme SLL reduction,the DConv/GA is introduced.In this technique,the same procedure of the aforementioned Conv/GA technique is performed on the resultant even and odd excitation vectors.It provides a relatively wider HPBWthan the original LAA with about quad-fold reduction in the SLL. 展开更多
关键词 array synthesis convolution process genetic algorithm(GA) half power beamwidth(HPBW) linear antenna array(LAA) side lobe level(SLL) quality of service(QOS)
下载PDF
Effective approach for conformal subarray design based on maximum entropy of planar mappings
4
作者 Xiao-Dong Zheng Sheng-Teng Shi +3 位作者 Jun Ou-Yang Feng Yang Qammer Abbasi Abubakar Sharif 《Journal of Electronic Science and Technology》 EI CAS CSCD 2024年第3期16-25,共10页
In this paper,an effective algorithm for optimizing the subarray of conformal arrays is proposed.The method first divides theconformal array into several first-level subarrays.It uses the X algorithm to solve the feas... In this paper,an effective algorithm for optimizing the subarray of conformal arrays is proposed.The method first divides theconformal array into several first-level subarrays.It uses the X algorithm to solve the feasible solution of first-level subarray tiling and employs the particle swarm algorithm to optimize the conformal array subarray tiling scheme with the maximum entropy of the planar mapping as the fitness function.Subsequently,convex optimization is applied to optimize the subarray amplitude phase.Data results verify that the method can effectively find the optimal conformal array tiling scheme. 展开更多
关键词 Conformal array Irregular arrays Particle swarm optimal algorithm Maximum entropy model
下载PDF
Developing Three-Dimensional Beamshaping Techniques on Volumetric Random Arrays to Suppress Array Sidelobes
5
作者 Shihyuan Yeh 《Open Journal of Antennas and Propagation》 2023年第2期36-48,共13页
This paper proposes a three-dimensional (3-D) amplitude tapering technique on volumetric random arrays to minimize array sidelobes and emulate phased array operations on mobile platforms. Our ultimate goal is to reali... This paper proposes a three-dimensional (3-D) amplitude tapering technique on volumetric random arrays to minimize array sidelobes and emulate phased array operations on mobile platforms. Our ultimate goal is to realize wireless phased array applications carried out by mobile platforms;in this paper, we focus on the development of collaborative beamforming algorithms. This beamshaping technique mitigates the discontinuity of the current distribution along the array aperture and lower array sidelobe level (SLL) by specially paying attention to the array element’s depth deviation. In this work, step by step amplitude tapering procedures are clearly illustrated. Further, a reconfigurable phased array with sixteen patch antennas is tested to verify the fidelity of the 3-D beamshaping algorithm. Measured and simulated radiation patterns are benchmarked to evaluate the sidelobe suppression results, and the best sidelobe suppressed region is around the array’s main beam. 展开更多
关键词 Amplitude Tapering Antenna arrays array Beamforming array Beamshaping Mobile Platforms Random array Reconfigurable array Sidelobe Level Unmanned Aerial Vehicle
下载PDF
Recent Advances in In-Memory Computing:Exploring Memristor and Memtransistor Arrays with 2D Materials 被引量:1
6
作者 Hangbo Zhou Sifan Li +1 位作者 Kah-Wee Ang Yong-Wei Zhang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第7期1-30,共30页
The conventional computing architecture faces substantial chal-lenges,including high latency and energy consumption between memory and processing units.In response,in-memory computing has emerged as a promising altern... The conventional computing architecture faces substantial chal-lenges,including high latency and energy consumption between memory and processing units.In response,in-memory computing has emerged as a promising alternative architecture,enabling computing operations within memory arrays to overcome these limitations.Memristive devices have gained significant attention as key components for in-memory computing due to their high-density arrays,rapid response times,and ability to emulate biological synapses.Among these devices,two-dimensional(2D)material-based memristor and memtransistor arrays have emerged as particularly promising candidates for next-generation in-memory computing,thanks to their exceptional performance driven by the unique properties of 2D materials,such as layered structures,mechanical flexibility,and the capability to form heterojunctions.This review delves into the state-of-the-art research on 2D material-based memristive arrays,encompassing critical aspects such as material selection,device perfor-mance metrics,array structures,and potential applications.Furthermore,it provides a comprehensive overview of the current challenges and limitations associated with these arrays,along with potential solutions.The primary objective of this review is to serve as a significant milestone in realizing next-generation in-memory computing utilizing 2D materials and bridge the gap from single-device characterization to array-level and system-level implementations of neuromorphic computing,leveraging the potential of 2D material-based memristive devices. 展开更多
关键词 2D materials MEMRISTORS Memtransistors Crossbar array In-memory computing
下载PDF
Customization of FeNi alloy nanosheet arrays inserted with biomass-derived carbon templates for boosted electromagnetic wave absorption 被引量:1
7
作者 Xuanqi Yang Honghan Wang +5 位作者 Jing Chen Qingda An Zuoyi Xiao Jingai Hao Shangru Zhai Junye Sheng 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期812-824,共13页
Electromagnetic wave(EMW)-absorbing materials have considerable capacity in the military field and the prevention of EMW radiation from harming human health.However,obtaining lightweight,high-performance,and broadband... Electromagnetic wave(EMW)-absorbing materials have considerable capacity in the military field and the prevention of EMW radiation from harming human health.However,obtaining lightweight,high-performance,and broadband EMW-absorbing material remains an overwhelming challenge.Creating dielectric/magnetic composites with customized structures is a strategy with great promise for the development of high-performance EMW-absorbing materials.Using layered double hydroxides as the precursors of bimetallic alloys and combining them with porous biomass-derived carbon materials is a potential way for constructing multi-interface heterostructures as efficient EMW-absorbing materials because they have synergistic losses,low costs,abundant resources,and light weights.Here,FeNi alloy nanosheet array/Lycopodium spore-derived carbon(FeNi/LSC)was prepared through a simple hydrothermal and carbonization method.FeNi/LSC presents ideal EMW-absorbing performance by benefiting from the FeNi alloy nanosheet array,sponge-like structure,capability for impedance matching,and improved dielectric/magnetic losses.As expected,FeNi/LSC exhibited the minimum reflection loss of-58.3 dB at 1.5 mm with 20wt%filler content and a widely effective absorption bandwidth of 4.92 GHz.FeNi/LSC composites with effective EMW-absorbing performance provide new insights into the customization of biomass-derived composites as high-performance and lightweight broadband EMW-absorbing materials. 展开更多
关键词 spore-derived carbon FeNi alloy nanosheet array multi-interface heterostructures synergistic effect efficient electromagnet-ic wave absorption
下载PDF
Low profile cavity-embedded ultra-wideband UHF array antenna with end-fire beams 被引量:1
8
作者 Huan He Wen-Song Wang 《Journal of Electronic Science and Technology》 EI CAS CSCD 2024年第2期24-35,共12页
A low-profile,vertically polarized,ultra-wideband array antenna with end-fire beams operating in an ultra-high frequency(UHF)band is developed in this paper.The array antenna consists of 1×16 log-periodic top-hat... A low-profile,vertically polarized,ultra-wideband array antenna with end-fire beams operating in an ultra-high frequency(UHF)band is developed in this paper.The array antenna consists of 1×16 log-periodic top-hat loaded monopole antenna arrays and is feasible to embed into a shallow cavity to further reduce the array height.Capacitance is introduced in the proposed antenna element to reduce profile height and the rectangular top hats are carefully designed to minimize the transverse dimension.Simulated results show that when the antenna array operates in a frequency range of 300 MHz-900 MHz,the end-fire radiation pattern achieves±45°scanning range in the horizontal plane.Then prototypes of the proposed end-fire antenna element and a uniformly spaced linear array(1×2)are fabricated and validated.The end-fire antenna array should be suitable for airborne applications where low-profile and conformal scanning phased antenna arrays with end-fire radiations are required.This design is attractive for airborne platform applications that are used to search,discover,identify,and scout the aerial target with vertically polarized beams. 展开更多
关键词 End-fire radiation Low-profile Vertical polarization Log-periodic array
下载PDF
Application and prospect of the fluid cooling system of solar arrays for probing the Sun 被引量:1
9
作者 Kangli Bao Xiaofei Zhu +5 位作者 Jianchao Feng Liu Liu Xiaofeng Zhang Zhiming Cai Jun Lin Yonghe Zhang 《Astronomical Techniques and Instruments》 CSCD 2024年第1期62-70,共9页
The Solar Close Observations and Proximity Experiments(SCOPE)mission,which has been proposed by the Yunnan Observatories,Chinese Academy of Sciences,aiming to operate at a distance of 5 to 10 solar radii from the Sun,... The Solar Close Observations and Proximity Experiments(SCOPE)mission,which has been proposed by the Yunnan Observatories,Chinese Academy of Sciences,aiming to operate at a distance of 5 to 10 solar radii from the Sun,plans to complete the in situ detection of the solar eruption process and observation of the magnetic field structure response.The solar flux received by the satellite ranges from 10^(3) to 10^(6) Wm^(-2),which poses challenges for thermal management of the solar arrays.In this work,the solar array cooling system of the Parker Solar Probe is discussed,the developments of the fluid loop technique are reviewed,and a research plan for a next-generation solar array cooling system is proposed.This paper provides a valuable reference for novel thermal control systems in spacecraft for solar observation. 展开更多
关键词 In situ detection of solar eruption Solar array cooling system Pumped fluid loop High heat flux dissipation
下载PDF
Design and construction of charged-particle telescope array for study of exotic nuclear clustering structure
10
作者 Zheng‑Li Liao Xi‑Guang Cao +2 位作者 Yu‑Xuan Yang Chang‑Bo Fu Xian‑Gai Deng 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第8期114-123,共10页
The exploration of exotic shapes and properties of atomic nuclei,e.g.,αcluster and toroidal shape,is a fascinating field in nuclear physics.To study the decay of these nuclei,a novel detector aimed at detecting multi... The exploration of exotic shapes and properties of atomic nuclei,e.g.,αcluster and toroidal shape,is a fascinating field in nuclear physics.To study the decay of these nuclei,a novel detector aimed at detecting multipleα-particle events was designed and constructed.The detector comprises two layers of double-sided silicon strip detectors(DSSD)and a cesium iodide scintillator array coupled with silicon photomultipliers array as light sensors,which has the advantages of their small size,fast response,and large dynamic range.DSSDs coupled with cesium iodide crystal arrays are used to distinguish multipleαhits.The detector array has a compact and integrated design that can be adapted to different experimental conditions.The detector array was simulated using Geant4,and the excitation energy spectra of someα-clustering nuclei were reconstructed to demonstrate the performance.The simulation results show that the detector array has excellent angular and energy resolutions,enabling effective reconstruction of the nuclear excited state by multipleαparticle events.This detector offers a new and powerful tool for nuclear physics experiments and has the potential to discover interesting physical phenomena related to exotic nuclear structures and their decay mechanisms. 展开更多
关键词 Cluster decay Toroidal structure Telescope array SIPM Energy resolution
下载PDF
Simulation and fabrication of in vitro microfluidic microelectrode array chip for patterned culture and electrophysiological detection of neurons
11
作者 Yan Yang Shihong Xu +7 位作者 Yu Deng Yaoyao Liu Kui Zhang Shiya Lv Longze Sha Qi Xu Xinxia Cai Jinping Luo 《Nanotechnology and Precision Engineering》 EI CAS CSCD 2024年第2期1-10,共10页
To enable the detection and modulation of modularized neural networks in vitro,this study proposes a microfluidic microelectrode array chip for the cultivation,compartmentalization,and control of neural cells.The chip... To enable the detection and modulation of modularized neural networks in vitro,this study proposes a microfluidic microelectrode array chip for the cultivation,compartmentalization,and control of neural cells.The chip was designed based on the specific structure of neurons and the requirements for detection and modulation.Finite-element analysis of the chip’s flow field was conducted using the COMSOL Multiphysics software,and the simulation results show that the liquid within the chip can flow smoothly,ensuring stable flow fields that facilitate the uniform growth of neurons within the microfluidic channels.By employing MEMS technology in combination with nanomaterial modification techniques,the microfluidic microelectrode array chip was fabricated successfully.Primary hippocampal neurons were cultured on the chip,forming a well-defined neural network.Spontaneous electrical activity of the detected neurons was recorded,exhibiting a 23.7%increase in amplitude compared to neuronal discharges detected on an open-field microelectrode array.This study provides a platform for the precise detection and modulation of patterned neuronal growth in vitro,potentially serving as a novel tool in neuroscience research. 展开更多
关键词 Microfluidic Microelectrode array In vitro Neural chip
下载PDF
Chiral bound states in a staggered array of coupled resonators
12
作者 金伍林 李静 +2 位作者 卢竞 龚志瑞 周兰 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期124-130,共7页
We study the chiral bound states in a coupled-resonator array with staggered hopping strengths,which interacts with a two-level small atom through a single coupling point or two adjacent ones.In addition to the two ty... We study the chiral bound states in a coupled-resonator array with staggered hopping strengths,which interacts with a two-level small atom through a single coupling point or two adjacent ones.In addition to the two typical bound states found above and below the energy bands,this system presents an extraordinary chiral bound state located within the energy gap.We use the chirality to quantify the breaking of the mirror symmetry.We find that the chirality value undergoes continuous changes by tuning the coupling strengths.The preferred direction of the chirality is controlled not only by the competition between the intracell and the intercell hoppings in the coupled-resonator array,but also by the coherence between the two coupling points.In the case with one coupling point,the chirality values varies monotonously with difference between the intracell hopping and the intercell hoppings.While in the case with two coupling points,due to the coherence between the two coupling points the perfect chiral states can be obtained. 展开更多
关键词 bound states two-level small atom coupled-resonator array CHIRALITY
下载PDF
Overcoming the Limits of Cross-Sensitivity:Pattern Recognition Methods for Chemiresistive Gas Sensor Array
13
作者 Haixia Mei Jingyi Peng +4 位作者 Tao Wang Tingting Zhou Hongran Zhao Tong Zhang Zhi Yang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第12期285-341,共57页
As information acquisition terminals for artificial olfaction,chemiresistive gas sensors are often troubled by their cross-sensitivity,and reducing their cross-response to ambient gases has always been a difficult and... As information acquisition terminals for artificial olfaction,chemiresistive gas sensors are often troubled by their cross-sensitivity,and reducing their cross-response to ambient gases has always been a difficult and important point in the gas sensing area.Pattern recognition based on sensor array is the most conspicuous way to overcome the cross-sensitivity of gas sensors.It is crucial to choose an appropriate pattern recognition method for enhancing data analysis,reducing errors and improving system reliability,obtaining better classification or gas concentration prediction results.In this review,we analyze the sensing mechanism of crosssensitivity for chemiresistive gas sensors.We further examine the types,working principles,characteristics,and applicable gas detection range of pattern recognition algorithms utilized in gas-sensing arrays.Additionally,we report,summarize,and evaluate the outstanding and novel advancements in pattern recognition methods for gas identification.At the same time,this work showcases the recent advancements in utilizing these methods for gas identification,particularly within three crucial domains:ensuring food safety,monitoring the environment,and aiding in medical diagnosis.In conclusion,this study anticipates future research prospects by considering the existing landscape and challenges.It is hoped that this work will make a positive contribution towards mitigating cross-sensitivity in gas-sensitive devices and offer valuable insights for algorithm selection in gas recognition applications. 展开更多
关键词 Pattern recognition Sensor array Chemiresistive gas sensor CROSS-SENSITIVITY Artificial olfactory
下载PDF
A Retrodirective Array Enabled by CMOS Chips for Two-Way Wireless Communication with Automatic Beam Tracking
14
作者 Jiacheng Guo Yizhu Shen +2 位作者 Guoqing Dong Zhuang Han Sanming Hu 《Engineering》 SCIE EI CAS CSCD 2024年第6期196-207,共12页
This article proposes and demonstrates a retrodirective array(RDA)for two-way wireless communication with automatic beam tracking.The proposed RDA is enabled by specifically designed chips made using a domestic comple... This article proposes and demonstrates a retrodirective array(RDA)for two-way wireless communication with automatic beam tracking.The proposed RDA is enabled by specifically designed chips made using a domestic complementary metal-oxide semiconductor(CMOS)process.The highly integrated CMOS chip includes a receiving(Rx)chain,a transmitting(Tx)chain,and a unique tracking phaselocked loop(PLL)for the crucial conjugated phase recovery in the RDA.This article also proposes a method to reduce the beam pointing error(BPE)in a conventional RDA.To validate the above ideas simply yet without loss of generality,a 2.4 GHz RDA is demonstrated through two-way communication links between the Rx and Tx chains,and an on-chip quadrature coupler is designed to achieve a nonretrodirective signal suppression of 23 dBc.The experimental results demonstrate that the proposed RDA,which incorporates domestically manufactured low-cost 0.18 lm CMOS chips,is capable of automatically tracking beams covering±40with a reduced BPE.Each CMOS chip in the RDA has a compact size of 4.62 mm^(2) and a low power consumption of 0.15 W.To the best of the authors’knowledge,this is the first research to demonstrate an RDA with a fully customized CMOS chip for wireless communication with automatic beam tracking。 展开更多
关键词 Automatic beam tracking CMOS Retrodirective array Two-way communication
下载PDF
A Generalized Array Factor for Time-Modulated Hexagonal Based Antenna Array Geometry With Novel Trapezoidal Switching
15
作者 Gopi Ram 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第9期1967-1972,共6页
The concept of the time-modulated array has been emerging as an alternative to the complex phase shifters,which lowers the cost of the array feeding network due to the utilization of radio frequency(RF)switches.The va... The concept of the time-modulated array has been emerging as an alternative to the complex phase shifters,which lowers the cost of the array feeding network due to the utilization of radio frequency(RF)switches.The various forms of hexagonal antenna array geometries can be used for applications like surveillance tracking in phased array radar and wireless communication systems.This work proposes the generalized array factor(AF)for the hexagonal antenna array geometry based on time modulation.The time modulation in generalized hexagonal geometry can maintain the fixed static amplitude excitation,giving more flexibility over time.Furthermore,a novel trapezoidal switching function is also proposed and applied to the generalized array factor to enable future researchers to use this array factor in the field of advancement to observe how switching schemes like trapezoidal and rectangular affect the array pattern's side lobe level(SLL).The generalized equation can be utilized for the analysis and synthesis of radiation characteristics of the time-modulated hexagonal array(TMHA),time-modulated concentric hexagonal array(TMCHA),time-modulated hexagonal cylindrical array(TMHCA),and time-modulated hexagonal concentric cylindrical array(TMHCCA).The numerical result illustrates the generation of AF of time-modulated hexagonal structures and also shows that the trapezoidal switching sequence outperforms the rectangular switch using the cat swarm optimization(CSO)approach. 展开更多
关键词 Hexagonal array geometry radiation pattern time-modulation trapezoidal pulse
下载PDF
Internal phase control of fiber laser array based on photodetector array
16
作者 靳凯凯 龙金虎 +5 位作者 常洪祥 粟荣涛 张嘉怡 陈思雨 马阎星 周朴 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期320-326,共7页
Coherent beam combining(CBC) of fiber laser array is a promising technique to realize high output power while maintaining near diffraction-limited beam quality. To implement CBC, an appropriate phase control feedback ... Coherent beam combining(CBC) of fiber laser array is a promising technique to realize high output power while maintaining near diffraction-limited beam quality. To implement CBC, an appropriate phase control feedback structure should be established to realize phase-locking. In this paper, an innovative internal active phase control CBC fiber laser array based on photodetector array is proposed. The dynamic phase noises of the laser amplifiers are compensated before being emitted into free space. And the static phase difference compensation of emitting laser array is realized by interference measurement based on photodetector array. The principle of the technique is illustrated and corresponding simulations are carried out, and a CBC system with four laser channels is built to verify the technique. When the phase controllers are turned on, the phase deviation of the laser array is less than λ/20, and ~ 95% fringe contrast of the irradiation distribution is obtained. The technique proposed in this paper could provide a reference for the system design of a massive high-power CBC system. 展开更多
关键词 fiber laser laser array coherent beam combining internal phase control
下载PDF
Flexible capacitive pressure sensor based on interdigital electrodes with porous microneedle arrays for physiological signal monitoring
17
作者 Jiahui Xu Minghao Wang +9 位作者 Minyi Jin Siyan Shang Chuner Ni Yili Hu Xun Sun Jun Xu Bowen Ji Le Li Yuhua Cheng Gaofeng Wang 《Nanotechnology and Precision Engineering》 EI CAS CSCD 2024年第1期18-31,共14页
Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stab... Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer. 展开更多
关键词 Capacitive pressure sensor Microneedle array Porous PDMS Interdigital electrode
下载PDF
Study on plasma expansion model of primary discharge on spacecraft solar array
18
作者 Dejie WEI Jianwen WU Liying ZHU 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第11期87-95,共9页
In the space plasma environment, primary discharge may occur on the solar array and evolve into a destructive sustained arc, which threatens the safe operation of the spacecraft. Based on the plasma expansion fluid th... In the space plasma environment, primary discharge may occur on the solar array and evolve into a destructive sustained arc, which threatens the safe operation of the spacecraft. Based on the plasma expansion fluid theory, a new multicomponent plasma expansion model is proposed in this study, which takes into account the effects of ion species, ion number, initial discharge current, and Low Earth Orbit(LEO) plasma environment. The expansion simulation of single-component and multicomponent ions is carried out respectively, and the variations of plasma number density, expansion distance, and speed during the expansion process are obtained.Compared with the experimental results, the evolution of propagation distance and speed is closed and the error is within a reasonable range, which verifies the validity and rationality of the model. The propagation characteristics of the primary discharge on the solar array surface and the influence of the initial value on the maximum propagation distance and the propagation current peaks are investigated. This study can provide important theoretical support for the propagation and evolution of the primary discharge and the key behavior of the transition to secondary discharge on spacecraft solar array. 展开更多
关键词 primary discharge plasma expansion propagation characteristics spacecraft solar array
下载PDF
Theoretical optimization of micropillar arrays for structurally stable bioinspired dry adhesives
19
作者 Ke Ni Zhengzhi Wang 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2024年第2期124-129,共6页
Inspired by the excellent adhesion performances of setae structure from organisms,micro/nano-pillar array has become one of the paradigms for adhesive surfaces.The micropillar arrays are composed of the resin pillars ... Inspired by the excellent adhesion performances of setae structure from organisms,micro/nano-pillar array has become one of the paradigms for adhesive surfaces.The micropillar arrays are composed of the resin pillars for adhesion and the substrate with different elastic modulus for supporting.The stress singularity at the bi-material corner between the pillars and the substrate can induce the failure of the micropillar-substrate corner and further hinder the fabrication and application of micropillar arrays,yet the design for the stability of the micropillar array lacks systematical and quantitative guides.In this work,we develop a semi-analytical method to provide the full expressions for the stress distribution within the bi-material corner combining analytical derivations and numerical calculations.The predictions for the stress within the singularity field can be obtained based on the full expressions of the stress.The good agreement between the predictions and the FEM results demonstrates the high reliability of our method.By adopting the strain energy density factor approach,the stability of the pillar-substrate corner is assessed by predicting the failure at the corner.For the elastic mismatch between the pillar and substrate given in this paper,the stability can be improved by increasing the ratio of the shear modulus of the substrate to that of the micropillar.Our study provides accurate predictions for the stress distribution at the bi-material corner and can guide the optimization of material combinations of the pillars and the substrate for more stable bioinspired dry adhesives. 展开更多
关键词 Micropillar array Stability Bi-material corner Dry adhesive
下载PDF
The large-scale modular BGO detection array(LAMBDA)design and test
20
作者 Yao-De Sheng Lu-Yang Song +28 位作者 Jun Su Shi-Lun Jin Fei Lu Yang-Ping Shen Jun-Feng Chen Li-Yong Zhang Jian-Jun He Xin-Yue Li Hong-Na Liu Feng-Shou Zhang Meng-Lin Qiu Shen Lin Hao Zhang Luo-Huan Wang Zi-Ming Li Yin-Ji Chen Xin-Zhi Jiang Xin Chen Zhi-Lin Shen Feng-Cheng Liu Zhi-Wei Qin Lin Wang Yi-Tong Huang Xiang Li Si-Ze Chen You-Bao Wang Zhi-Hong Li Bing Guo Wei-Ping Liu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第11期228-236,共9页
Total absorption gamma-ray spectroscopy(TAGS)is a powerful tool for measuring complexγ transitions,which has been effectively applied to the study of reactor decay heat.This paper presents the design of a new TAGS de... Total absorption gamma-ray spectroscopy(TAGS)is a powerful tool for measuring complexγ transitions,which has been effectively applied to the study of reactor decay heat.This paper presents the design of a new TAGS detector,the large-scale modular BGO detection array(LAMBDA),tailored for measuringβ-decay intensity distributions of fission products.The modular design allows the LAMBDA detectors to be assembled in various configurations.The final version of LAMBDA consists of 102 identical 60 mm×60 mm×120 mm BGO crystals and exhibits a high full-energy peak efficiency exceeding 80%at 0.5∼8 MeV based on a Monte Carlo simulation.Currently,approximately half of the LAMBDA modules have been manufactured.Tests usingγ-ray sources and nuclear reactions demonstrated favorable energy resolution,energy linearity,and efficiency uniformity across the modules.Forty-eight modules have been integrated into the prototype LAMBDA-I.The capability of LAMBDA-I inβ-delayedγ-decay experiments was evaluated by commissioning measurements using the ^(152)Eu source. 展开更多
关键词 Total absorption gamma-ray spectroscopy Reactor decay heat BETA-DECAY BGO detector array LAMBDA
下载PDF
上一页 1 2 118 下一页 到第
使用帮助 返回顶部