检索结果-南通市图书馆

Fabrication of Bio-inspired Superamphiphobic Aluminum Alloy Surface with Oil-triggered Wenzel-Slippery Transition via Femtosecond Laser

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

Journal of Bionic Engineering 2024年第3期21卷 1375-1387页

作者： weijian liu Feng Guan Fulin Zhang Chenrui Wang Wei Zheng Lu Zhai Zhaohua Lin Chunbao liu AVIC Shenyang Aircraft Corporation Shenyang110000China School of Mechanical and Aerospace Engineering Jilin UniversityChangchun130022China

Surface-tension-confined microfluidic devices are platforms for manipulating 2D droplets based on patterned surfaces with special *** have great potential for various applications,but are still in the early stages of development and face some challenges that need to be *** study,inspired by the Wenzel and slippery transition of rose petal,develops a Patterned Oil-triggered Wenzel-slippery Surface(POWS)to examine the microfluidic devices.A laser-chemical composite method is established to fabricate POWSs,which take rose-petal-like microstructures as wettability pattern and a superamphiphobic surface as the *** prepared POWSs switched between high adhesion superhydrophobic state and the slippery liquid-infused surface state through adding or removing the lubricant *** the high adhesion superhydrophobic state,the droplets can be sticked on the *** the slippery liquid-infused state,the droplet can slide along the wettability pattern as the designed route.A POWS-based droplet reactor is further constructed,on which,the droplets can be remotely controlled to move,mix and react,as *** a POWS,which manipulates droplets with surface tension controlled by the switchable wettability patterns,would be a promising candidate to construct multiple surface-tension-confined microfluidic *** addition,the fabrication technique and design principle proposed here may aid the development of various field related to the bio-inspired surfaces,such as water collection,desalination and high throughput analysis,etc.

关键词： Biomaterials Bio-inspired surface Oil-triggered wenzel-slippery transition Superhydrophobicity Femtosecondlaser

A target parameter estimation method via atom-reconstruction in radar mainlobe jamming

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

Journal of Systems Engineering and Electronics 2024年第2期35卷 350-360页

作者： ZHOU Bilei liu weijian LI Rongfeng CHEN Hui ZHANG Liang DU Qinglei LI Binbin CHEN Hao Air Force Early Warning Academy Wuhan 430019China Aerospace Nanhu Electronic Information Technology Co. Ltd.Jingzhou 434000China

Mainlobe jamming(MLJ)brings a big challenge for radar target detection,tracking,and *** suppression of MLJ is a hard task and an open problem in the electronic counter-counter measures(ECCM)*** parameters and target direction estimation is difficult in radar MLJ.A target parameter estimation method via atom-reconstruction in radar MLJ is proposed in this *** proposed method can suppress the MLJ and simultaneously provide high estimation accuracy of target range and ***,the eigen-projection matrix processing(EMP)algorithm is adopted to suppress the MLJ,and the target range is estimated effectively through the beamforming and pulse *** the target angle can be effectively estimated by the atom-reconstruction *** any prior knowledge,the MLJ can be canceled,and the angle estimation accuracy is well ***,the proposed method does not have strict requirement for radar array construction,and it can be applied for linear array and planar ***,the proposed method can effectively estimate the target azimuth and elevation simultaneously when the target azimuth(or elevation)equals to the jamming azimuth(or elevation),because the MLJ is suppressed in spatial plane dimension.

关键词： mainlobe jamming anti-jamming atom-reconstruction radar

基于脉内频率编码联合调频斜率捷变波形的ISRJ对抗方法

在线全文

学校读者我要写书评

暂无评论

雷达学报（中英文） 2024年第5期13卷 1019-1036页

作者：王晓戈李槟槟陈辉刘维建朱永哲倪萌钰空军预警学院武汉430019 中国人民解放军93209部队北京100094

间歇采样转发干扰(ISRJ)是一种脉内相参干扰,能在目标斜距前后形成多个逼真假目标来严重影响雷达检测,是当前电子反对抗的热点之一。针对这一问题,该文提出了一种基于脉内频率编码联合调频斜率捷变波形的抗ISRJ方法。首先,雷达发射脉内... 详细信息

间歇采样转发干扰(ISRJ)是一种脉内相参干扰,能在目标斜距前后形成多个逼真假目标来严重影响雷达检测,是当前电子反对抗的热点之一。针对这一问题,该文提出了一种基于脉内频率编码联合调频斜率捷变波形的抗ISRJ方法。首先,雷达发射脉内频率编码联合调频斜率捷变信号,通过子脉冲中心频率、调频斜率捷变提高子脉冲间相互掩护能力。之后依据发射信号子脉冲斜率变化时序将回波信号划分为多个切片。然后利用模糊C均值(FCM)算法对回波切片进行干扰识别。最后在分数阶域和时域对回波信号进行级联滤波。仿真结果表明,FCM方法在信噪比(SNR)大于-2.5 dB和干信比(JSR)大于5 dB时,能100%识别干扰机同步采样场景下回波中的受干扰回波切片。在较高JSR和低SNR下,所提方法能有效减少目标能量损失并抑制剩余干扰产生的距离旁瓣。在JSR为50 dB时,干扰抑制后的目标检测概率可达90%以上。

关键词：间歇采样转发干扰频率编码联合调频斜率捷变分数阶傅里叶变换时域滤波电子反对抗

在线全文

学校读者我要写书评

暂无评论

天波超视距雷达非均匀采样信号频谱重构

系统工程与电子技术 2024年第4期46卷 1236-1246页

作者：陈子睿陈阿磊刘维建杨军陈文峰马晓岩空军预警学院湖北武汉430019

受瞬态干扰影响和空海同时探测的需求,在长相参积累时间条件下,天波超视距雷达(over-the-horizon radar,OTHR)回波信号的有效采样点往往缺损且非均匀,严重影响目标检测性能。针对此问题,提出了一种基于压缩感知的OTHR频谱重构方法。首先... 详细信息

受瞬态干扰影响和空海同时探测的需求,在长相参积累时间条件下,天波超视距雷达(over-the-horizon radar,OTHR)回波信号的有效采样点往往缺损且非均匀,严重影响目标检测性能。针对此问题,提出了一种基于压缩感知的OTHR频谱重构方法。首先,建立了OTHR频域信号的稀疏模型;然后,提出了快速自适应复近似消息传递(fast adaptive complex approximate message passing,FACAMP)频谱重构算法并给出了算法实现步骤;最后,利用FACAMP算法实现了OTHR频谱重构并分析了重构性能。与现有重构算法相比,FACAMP算法具有重构精度高、运算复杂度低、可自适应调整参数和保留背景噪声高斯性的优势。理论分析和仿真实验均验证了所提算法的有效性。

关键词：天波超视距雷达压缩感知频谱重构复近似消息传递

Beam resource scheduling for a VHF-MIMO radar network in low-angle tracking

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第4期36卷 423-441页

作者： Haowei ZHANG weijian liu Taiyong FEI Air and Missile Defense College Air Force Engineering UniversityXi’an 710051China Air Force Early Warning Academy Wuhan 410039China

The low-angle tracking in multipath interference is a challenging problem for the Very High Frequency(VHF)*** colocated Multi-Input Multi-Output(MIMO)technique can remedy such a *** this paper,a Joint Beam-Target Assignment and Power Allocation(JBTAPA)strategy is proposed for the VHF-MIMO radar network tracking low-angle *** core of the JBTAPA strategy is to improve the worst tracking accuracy among multiple targets by assigning appropriate beams to targets and allocating the power resource in each beam using the feedback information in the tracking *** into account the transmit multipath and receive multipath,we derive the Cramer-Rao Lower Bound(CRLB)on angle estimate,which is then incor-porated in the Predicted Conditional CRLB(PC-CRLB).A more accurate and consistent lower bound is provided as the optimization metric since the PC-CRLB is based on the most recently real-ized measurements.A two-stage-based technique is proposed to solve the JBTAPA problem,which is originally *** results verify the effectiveness and efficiency of the proposed *** results also imply that the target reflectivity plays one of the important roles in resource allocation.

关键词： Convex optimization Low-angle tracking MIMO radar PC-CRLB Resource allocation

Resource saving based dwell time allocation and detection threshold optimization in an asynchronous distributed phased array radar network

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第11期36卷 311-327页

作者： Haowei ZHANG weijian liu Xiao YANG Air and Missile Defense College Air Force Engineering UniversityXi’an 710051China Air Force Early Warning Academy Wuhan 410039China Chinese People’s Liberation Army 93557 Troops Shijiazhuang 050000China

The resource optimization plays an important role in an asynchronous Phased Array Radar Network(PARN)tracking multiple targets with Measurement Origin Uncertainty(MOU),i.e.,considering the false alarms and missed detections.A Joint Dwell Time Allocation and Detection Threshold Optimization(JDTADTO)strategy is proposed for resource saving in this *** Predicted Conditional Cramér-Rao Lower Bound(PC-CRLB)with Bayesian Detector and Amplitude Information(BD-AI)is derived and adopted as the tracking performance *** optimization model is formulated as minimizing the difference between the PC-CRLBs and the tracking precision thresholds under the constraints of upper and lower bounds of dwell time and false alarm *** is shown that the objective function is nonconvex due to the Information Reduction Factor(IRF)brought by the MOU.A cyclic minimizer-based solution is proposed for problem *** results confirm the flexibility and robustness of the JDTADTO strategy in both sufficient and insufficient resource *** results also reveal the effectiveness of the proposed strategy compared with the strategies adopting the BD without detection threshold optimization and amplitude information.

关键词： Asynchronous data fusion Bayesian detector Phased Array Radar Network(PARN) Predicted Conditional CramE´R-Rao Lower Bound(PC-CRLB) Resource management

A rescaling algorithm for multi-relaxation-time lattice Boltzmann method towards turbulent flows with complex configurations

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2023年第9期44卷 1597-1612页

作者： Haoyang LI weijian liu Yuhong DONG Shanghai Institute of Applied Mathematics and Mechanics School of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai UniversityShanghai 200072China Shanghai Frontier Science Center of Mechanoinformatics Shanghai UniversityShanghai 200072China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

Understanding and modeling flows over porous layers are of great industrial *** accurately solve the turbulent multi-scale flows on complex configurations,a rescaling algorithm designed for turbulent flows with the Chapman-Enskog analysis is *** mesh layout and the detailed rescaling procedure are also *** numerical simulations(DNSs)for a turbulent channel flow and a porous walled turbulent channel flow are performed with the three-dimensional nineteen-velocity(D3Q19)multiple-relaxation-time(MRT)lattice Boltzmann method(LBM)to validate the accuracy,adaptability,and computational performance of the present rescaling *** results,which are consistent with the previous DNS studies based on the finite difference method and the LBM,demonstrate that the present method can maintain the continuity of the macro values across the grid interface and is able to adapt to complex *** reasonable time consumption of the rescaling procedure shows that the present method can accurately calculate various turbulent flows with multi-scale and complex configurations while maintaining high computational efficiency.

关键词： slattice Boltzmann method(LBM) direct numerical simulation(DNS) rescaling algorithm complex configuration

Adaptive detection based on orthogonal partition of the primary and secondary data

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2014年第1期25卷 34-42页

作者： weijian liu Wenchong Xie Yongliang Wang College of Electronic Science and Engineering National University of Defense Technology Air Force Early Warning Academy

A novel adaptive detection scheme both for point-like and distributed targets in the presence of Gaussian disturbance in the partial y homogeneous environment （PHE） is proposed. The novel detection scheme is based on the orthogonal projection technique. Both the case of known covariance matrix structure and the case of unknown covariance matrix structure are con-sidered. For the former case, the closed-form statistical pro-perty of the novel detectors is derived. When the covariance matrix is unknown, the corresponding detectors have higher probabilities of detection （PDs） than their natural competitors. Moreover, they ensure constant false alarm rate （CFAR） property.

关键词： partially homogeneous environment (PHE) orthogo-nal partition orthogonal projection.

Multichannel adaptive signal detection: basic theory and literature review

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2022年第2期65卷 5-44页

作者： weijian liu Jun liu Chengpeng HAO Yongchan GAO Yong-Liang WANG Wuhan Electronic Information Institute Department of Electronic Engineering and Information Science University of Science and Technology of China State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences School of Electronic Engineering Xidian University

Multichannel adaptive signal detection uses test and training data jointly to form an adaptive detector to determine whether a target exists. The resulting adaptive detectors typically possess constant false alarm rate(CFAR) properties; thus, no additional CFAR processing is required. In addition, a filtering process is also not required because the filtering function is embedded in the adaptive detector. Adaptive detection typically exhibits better detection performance than the filtering-then-CFAR detection *** has been approximately 35 years since the first multichannel adaptive detector was proposed by Kelly in 1986. However, there are few overview articles on this topic. Thus, in this study, we present a tutorial overview of multichannel adaptive signal detection with an emphasis on the Gaussian background. We discuss the main design criteria for adaptive detectors, investigate the relationship between adaptive detection and filtering-then-CFAR detection techniques, investigate the relationship between adaptive detectors and adaptive filters, summarize typical adaptive detectors, present numerical examples, provide a comprehensive literature review, and discuss potential future research tracks.

关键词： constant false alarm rate multichannel signal signal mismatch statistical distribution subspace signal