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| 1 | Spectral tomographic imaging with aplanatic metalens显示文摘Tomography is an informative imaging modality that is usually implemented by mechanical scanning,owing to the limited depth-of-field(DOF)in conventional systems.However,recent imaging systems are working towards more compact and stable architectures;therefore,developing nonmotion tomography is highly desirable.Here,we propose a metalens-based spectral imaging system with an aplanatic GaN metalens(NA=0.78),in which large chromatic dispersion is used to access spectral focus tuning and optical zooming in the visible spectrum.After the function of wavelength-switched tomography was confirmed on cascaded samples,this aplanatic metalens is utilized to image microscopic frog egg cells and shows excellent tomographic images with distinct DOF features of the cell membrane and nucleus.Our approach makes good use of the large diffractive dispersion of the metalens and develops a new imaging technique that advances recent informative optical devices. | Chen Chen Wange Song Jia-Wern Chen Jung-Hsi Wang Yu Han Chen Beibei Xu Mu-Ku Chen Hanmeng Li Bin Fang Ji Chen Hsin Yu Kuo Shuming Wang Din Ping Tsai Shining Zhu Tao Li | 2019 | Light(Science & Applications)2019，8，1： | 12 |
| 2 | Switched adaptive active disturbance rejection control of variable structure near space vehicles based on adaptive dynamic programming显示文摘Based on the switched nonlinear system, a switched adaptive Active Disturbance Rejection Control(ADRC) law is proposed for the Variable Structure Near Space Vehicle(VSNSV) with unknown uncertainties and external disturbances. The reduced-order Extended State Observers(ESOs) are constructed for the attitude angle system and the angular rate system to estimate the total disturbance in real time. With the extended state introduced to counteract the effects of uncertainties and disturbances, a systematic procedure is presented for the synthesis of the switched adaptive ADRC strategy. Rigorous proof shows that the estimation errors of the reduced-order ESOs would converge to a small neighborhood of zero in finite time, and that the output of the closedloop system can track a given signal stably for a class of switching signals with average dwell time via the proposed approach. The variable gain control strategy based on Adaptive Dynamic Programming(ADP) with the actor-critic structure is also designed to improve the dynamic performance of the system. Simulation results verify the effectiveness and advantage of the proposed control scheme. | Chaoyang DONG Chen LIU Qing WANG Ligang GONG | 2019 | Chinese Journal of Aeronautics2019，32，7： | 10 |
| 3 | Development and applications of gain-switched fiber lasers[Invited]显示文摘We briefly review the development of gain-switched rare-earth-doped fiber lasers and their applications in wavelength conversion to mid-IR,supercontinuum generation,and medicine in recent years.We illustrate the similarities between gain-switching and Q-switching techniques that will provide tools for the design and optimization of the gain-switched fiber lasers.From the nature of the gain-switched fiber lasers,benefits of this kind of lasers to 2-μm region and in-band-pumped(two-level system)laser systems are obvious.Advantages of in-band-pumped 2-μm lasers are discussed and analyzed with a simple numerical simulation in terms of Tm-doped fiber lasers.We also propose the key factors in the development of the gain-switched fiber lasers and predict the future tendency. | Jianlong Yang Yulong Tang Jianqiu Xu | 2013 | Photonics Research2013，1，1： | 8 |
| 4 | 开关磁阻电机的模糊自适应简化控制显示文摘为解决开关磁阻电机运行中存在的强耦合、非线性等问题,将模糊自适应控制技术应用到开关磁阻电机调速控制中。通过分析运行中速度误差和误差增量对模糊控制输出量的影响,同时考虑到开关磁阻电机自身的特性,建立了带有校正因子的输出量与误差、误差变量之间的关系,在兼顾计算量和性能的基础上,提出了一种简化的校正因子选择方法,从而实现了根据运行条件在线改变模糊规则。同时,在一台8/6四相开关磁阻电机上分别采用传统PI控制和简化模糊自适应方法进行了试验验证。对比研究结果证明,简化的模糊自适应方法能够有效提高开关磁阻电机调速的鲁棒性。通过使用Matlab仿真,验证了校正因子对模糊控制的影响,简化的模糊自适应方法能够应用于不同的情况,具有较好的动静态性能。 | 马云龙 章玮 | 2014 | 机电工程2014，31，1： | 6 |
| 5 | Feedback Stabilization over Wireless Network Using Adaptive Coded Modulation显示文摘In this paper, we apply adaptive coded modulation (ACM) schemes to a wireless networked control system (WNCS)to improve the energy efficiency and increase the data rate over a fading channel. To capture the characteristics of varying rate,interference, and routing in wireless transmission channels, the concepts of equivalent delay (ED) and networked condition index (NCI)are introduced. Also, the analytic lower and upper bounds of EDs are obtained. Furthermore, we model the WNCS as a multicontroller switched system (MSS) under consideration of EDs and loss index in the wireless transmission. Sufficient stability condition of the closed-loop WNCS and corresponding dynamic state feedback controllers are derived in terms of linear matrix inequality (LMI).Numerical results show the validity and advantage of our proposed control strategies. | Li Yang Xin-Ping Guan~* Cheng-Nian Long Xiao-Yuan Luo Department of Electrical Engineering, University of Yanshan, Qinhuangdao 066004, PRC | 2008 | International Journal of Automation and computing2008，5，4： | 5 |
| 6 | L_2-gain Analysis and Anti-windup Design of Discretetime Switched Systems with Actuator Saturation显示文摘This paper investigates L2-gain analysis and anti-windup compensation gains design for a class of discrete-time switched systems with saturating actuators and L2 bounded disturbances by using the switched Lyapunov function approach.For a given set of anti-windup compensation gains,we firstly give a sufficient condition on tolerable disturbances under which the state trajectory starting from the origin will remain inside a bounded set for the corresponding closed-loop switched system subject to L2 bounded disturbances.Then,the upper bound on the restricted L2-gain is obtained over the set of tolerable disturbances.Furthermore,the antiwindup compensation gains aiming to determine the largest disturbance tolerance level and the smallest upper bound of the restricted L2-gain are presented by solving a convex optimization problem with linear matrix inequality(LMI) constraints.A numerical example is given to illustrate the effectiveness of the proposed design method. | Zhang, Xin-Quan Zhao, Jun | 2012 | International Journal of Automation and computing2012，9，4： | 5 |
| 7 | High-energy all-fiber gain-switched thulium-doped fiber laser for volumetric photoacoustic imaging of lipids显示文摘We demonstrate a high-energy all-fiber short wavelength gain-switched thulium-doped fiber laser for volumetric photoacoustic(PA)imaging of lipids.The laser cavity is constructed by embedding a short piece of gain fiber between a pair of fiber Bragg gratings(FBGs).Through using three pairs of FBGs with operation wavelengths at1700,1725,and 1750 nm,three similar lasers are realized with a cavity length of around 25 cm.Under a maximum pump energy of 300μJ at 1560 nm,laser pulse energies of 58.2,66.8,and 75.3μJ are,respectively,achieved with a minimum pulse width of<16.7 ns at a repetition rate of 10 kHz.Volumetric imaging of lipids is validated through scanning a fat beef slice with a PA microscopy system incorporated with the newly developed source,and a lateral resolution of 18.8μm and an axial resolution of 172.9μm are achieved.Moreover,the higher shooting speed of the developed source can potentially allow for increasing at twice the frame rate of current intravascular PA imaging. | CAN LI JIAWEI SHI XIATIAN WANG BOQUAN WANG XIAOJING GONG LIANG SONG KENNETH K.Y.WONG | 2020 | Photonics Research2020，8，2： | 4 |
| 8 | Fe3O4 nanoparticles as a saturable absorber for a tunable Q-switched dysprosium laser around 3μm显示文摘We demonstrate for the first time to our knowledge the use of Fe3O4 nanoparticles for Q-switching a tunable midinfrared(Mid-IR)Dy^3+-doped ZBLAN fiber laser around 3μm.The Q-switcher was fabricated by depositing the prepared Fe3O4 nanoparticles solution onto an Au mirror.Its nonlinear optical response was characterized using a mode locked Ho^3+/Pr^3+-codoped ZBLAN fiber laser at 2.87μm,and showed a modulation depth of 11.9%as well as a saturation intensity of 1.44 MW/cm^2.Inserting the device into a tunable Dy^3+-doped ZBLAN fiber laser,stable Q-switched pulses within the tunable range of 2812.4-3031.6 nm were obtained.When tuning the wavelength to 2931.2 nm,a maximum Q-switching output power of 111.0 mW was achieved with a repetition rate of 123.0 kHz and a pulse width of 1.25μs.The corresponding pulse energy was 0.90μJ.This demonstration suggests that Fe3O4 nanoparticles are a promising broadband saturable absorption material for mid-infrared operation. | JIAN YANG JIYI HU HONGYU LUO JIANFENG LI JISHU LIU XIAOHUI LI YONG LIU | 2020 | Photonics Research2020，8，1： | 4 |
| 9 | Real-time Performance Evaluation of Line Topology Switched Ethernet显示文摘Recently, switched Ethernet has become an active area of research because of its wide uses in industry. However, its uses have various real-time constraints on data communications. This paper analyzes the performance of the line topology switched Ethernet as a data acquisition network. Network calculus theory, which has been successfully applied to assess the real-time performance of packet-switched networks, is used to analyze the networks. To properly describe the activity of switches, a novel approach of modeling data flows into or out of switches is addressed. Based on our model, a concisely analytical expression of the maximal end-to-end delay in line topology switched Ethernet is derived. Finally, the relative simulation results are demonstrated. These results agree well with the analytical results, and thus they validate the data flow modeling techniques. | Fan Cen~* Tao Xing Ke-Tong Wu Institute of Acoustics, the Chinese Academy of Sciences, Beijing 100190, PRC | 2008 | International Journal of Automation and computing2008，5，4： | 4 |
| 10 | Observation of transition between multimode Q-switching and spatiotemporal mode locking显示文摘We report experimental observation of multimode Q-switching and spatiotemporal mode locking in a multimode fiber laser.A typical steady Q-switching state is achieved with a 1.88μs pulse duration,a 70.14 kHz repetition rate,and a 215.8 mW output power,corresponding to the single pulse energy of 3.08μJ.We find weak spatial filtering is essential to obtain stable Q-switched pulses,in contrast to the relatively stronger spatial filtering for spatiotemporal mode locking.Furthermore,a reversible transition process,as well as a critical bistable state,between multimode Q-switching and spatiotemporal mode locking,is achieved with specific spatial coupling and waveplates sets.We believe the results will not only contribute to understanding the complicated nonlinear dynamics in multimode,fiber-based platforms,but also benefit the development of promising high-pulse energy lasers. | Kewei Liu Xiaosheng Xiao Changxi Yang | 2021 | Photonics Research2021，9，4： | 3 |
| 11 | L log L criterion for a class of multitype superdiffusions with non-local branching mechanisms显示文摘In this paper, we provide a pathwise spine decomposition for multitype superdiffusions with nonlocal branching mechanisms under a martingale change of measure. As an application of this decomposition,we obtain a necessary and sufficient condition(called the L log L criterion) for the limit of the fundamental martingale to be non-degenerate. This result complements the related results obtained in Kyprianou et al.(2012),Kyprianou and Murillo-Salas(2013) and Liu et al.(2009) for superprocesses with purely local branching mechanisms and in Kyprianou and Palau(2018) for super Markov chains. | Zhen-Qing Chen Yan-Xia Ren Renming Song | 2019 | Science China Mathematics2019，62，8： | 3 |
| 12 | GERO: a general SCA-based readout ASIC for micro-pattern gas detectors with configurable storage depth and on-chip digitizer显示文摘The paper presents GEneral ReadOut (GERO), a general readout ASIC based on a switched capacitor array for micro-pattern gas detectors. It aims at providing general readout electronics for low-to-medium event-rate gas detectors with high sampling frequency, configurable storage depth, and data digitalization. The first prototype GERO chip integrates 16 channels and was fabricated using a 0.18-lm CMOS process. Each channel consists of a sampling array working in a ping-pong mode, a storage array with a 1024-cell depth, and 32 Wilkinson analog-todigital converters. The detailed design and test results are presented in the paper. | Xin-Yuan Zhao Feng Liu Zhi Deng Yi-Nong Liu | 2019 | Nuclear Science and Techniques2019，30，9： | 3 |
| 13 | Ultrafast polarization-dependent all-optical switching of germanium-based metaphotonic devices显示文摘Metamaterials play an important role in the modulation of amplitude and group delay in the terahertz(THz)regime on account of their optical properties,which are rare in natural materials.Here an ultrafast anisotropic switch of the plasmon-induced transparency(PIT)effect is experimentally and numerically demonstrated by metamaterial devices composed of two pairs of planar split-ring resonators and a pair of closed-ring resonators.By integration with a germanium(Ge)film,a recovery time of 3 ps and a decay constant of 785 fs are realized in the metadevice.Stimulated by the exterior optical pump,the PIT windows at different frequencies are switched off with an excellent property of slow light for vertical and horizontal THz polarizations,realizing an astonishing modulation depth as high as 99.06%.This work provides a new platform for ultrafast anisotropic metadevices tunable for amplitude and group delay. | HAO SUN YUZE HU YUHUA TANG JIE YOU JUNHU ZHOU HENGZHU LIU XIN ZHENG | 2020 | Photonics Research2020，8，3： | 3 |
| 14 | The design of predictive control with characterized set of initial condition for constrained switched nonlinear system显示文摘Stabilization of the constrained switched nonlinear systems is an attractive research subject. Predictive control can handle variable constraints well and make the system stable. Its stability is typically based on an assumption of initial feasibility of the optimization problem; however the set of initial conditions, starting from where a given predictive formulation is guaranteed to be feasible, is not explicitly characterized. In this paper, a hybrid predictive control method is proposed for a class of switched nonlinear systems with input constraints and un-measurable states. The main idea is to design a mixed controller using Lyapunov functions and a state observer, which switches appropriately between a bounded feedback controller and a predictive controller, and to give an explicitly characterized set of initial conditions to stabilize each closed-loop subsystem. For the whole switched nonlinear system, a suitable switched law based on the state estimation is designed to orchestrate the transitions between the consistituent modes and their respective controllers, and to ensure the whole closed-loop system's stability. The simulation results for a chemical process show the validity of the controller proposed in this paper. | BaiLi Su ShaoYuan Li QuanMin Zhu | 2009 | Science China(Technological Sciences)2009，52，2： | 3 |
| 15 | CDMA系统中Switched Beam的用户扇区及DOA估计显示文摘用最小二乘法在蜂窝小区中形成全覆盖的SwitchedBeam(SB).根据CDMA信号模型和多径信道模型,用最大似然(ML)法估计得到每个用户在每个扇区内加权幅度最大的路径,通过比较这些加权幅度的大小,确定用户的最强路径(主径)所在的扇区,得到下行信号的加权道;通过改变所在扇区的中心位置,使主径加权幅度达到最大可估计用户的来波方向(DOA).算法的运算量小,正确率高. | 沈建锋 王宗欣 卞正才 | 2003 | 复旦学报(自然科学版)2003，42，1： | 2 |
| 16 | Stability and Robust Stability of Switched Positive Linear Systems With All Modes Unstable显示文摘This paper is concerned with the stability and robust stability of switched positive linear systems(SPLSs) whose subsystems are all unstable. By means of the mode-dependent dwell time approach and a class of discretized co-positive Lyapunov functions, some stability conditions of switched positive linear systems with all modes unstable are derived in both the continuous-time and the discrete-time cases, respectively. The copositive Lyapunov functions constructed in this paper are timevarying during the dwell time and time-invariant afterwards. In addition, the above approach is extended to the switched interval positive systems. A numerical example is proposed to illustrate our approach. | Shaoxia Feng Juan Wang Jun Zhao | 2019 | IEEE/CAA Journal of Automatica Sinica2019，6，1： | 2 |
| 17 | Switching disturbance rejection attitude control of near space vehicles with variable structure显示文摘A switching disturbance rejection attitude control law is proposed for a near space vehicle(NSV) with variable structure.The multiple flight modes, system uncertainties and disturbances of the NSV are taken into account based on switched nonlinear systems. Compared with traditional backstepping design methods,the proposed method utilizes the added integrals of attitude angle and angular rate tracking errors to further decrease the tracking errors. Moreover, to reduce the computation complexity, a rapid convergent differentiator is employed to obtain the derivative of the virtual control command. Finally, for disturbance rejection, based on the idea from the extended state observer(ESO), two disturbance observers are designed by using non-smooth functions to estimate the disturbances in the switched nonlinear systems. All signals of the closed-loop system are proven to be uniformly ultimately bounded under the Lyapunov function framework. Simulation results demonstrate the effectiveness of the proposed control scheme. | GONG Ligang WANG Qing DONG Chaoyang | 2019 | Journal of Systems Engineering and Electronics2019，30，1： | 2 |
| 18 | Hybrid-integrated high-performance microwave photonic filter with switchable response显示文摘The integrated microwave photonic filter(MPF),as a compelling candidate for next-generation radio-frequency(RF)applications,has been widely investigated for decades.However,most integrated MPFs reported thus far have merely incorporated passive photonic components onto a chip-scale platform,while all necessary active devices are still bulk and discrete.Though few attempts to higher photonic integration of MPFs have been executed,the achieved filtering performances are fairly limited,which impedes the pathway to practical deployments.Here,we demonstrate,for the first time to our knowledge,an all-integrated MPF combined with high filtering performances,through hybrid integration of an In P chip-based laser and a monolithic silicon photonic circuit consisting of a dual-drive Mach–Zehnder modulator,a high-Q ring resonator,and a photodetector.This integrated MPF exhibits a high spectral resolution as narrow as 360 MHz,a wide-frequency tunable range covering the S-band to K-band(3 to 25 GHz),and a large rejection ratio of>40 d B.Moreover,the filtering response can be agilely switched between the bandpass and band-stop function with a transient respond time(48μs).Compared with previous MPFs in a similar integration level,the obtained spectral resolution in this work is dramatically improved by nearly one order of magnitude,while the valid frequency tunable range is broadened more than twice,which can satisfy the essential filtering requirements in actual RF systems.As a paradigm demonstration oriented to real-world scenarios,high-resolution RF filtering of realistic microwave signals aiming for interference rejection and channel selection is performed.Our work points out a feasible route to a miniaturized,high-performance,and cost-effective MPF leveraging hybrid integration approach,thus enabling a range of RF applications from wireless communication to radar toward the higher-frequency region,more compact size,and lower power consumption. | YUANSHENG TAO HAOWEN SHU XINGJUN WANG MING JIN ZIHAN TAO FENGHE YANG JINGBO SHI JUN QIN | 2021 | Photonics Research2021，9，8： | 2 |
| 19 | Nonvolatile reconfigurable dynamic Janus metasurfaces in the terahertz regime显示文摘Metasurfaces,especially tunable ones,have played a major role in controlling the amplitude,phase,and polarization of electromagnetic waves and attracted growing interest,with a view toward a new generation of miniaturized devices.However,to date,most existing reconfigurable devices are bounded in volatile nature with sustained external energy to maintain and single functionality,which restrict their further applications.Here,we demonstrate for the first time,to our knowledge,nonvolatile,reconfigurable,and dynamic Janus metasurfaces by incorporating phase-change material Ge_(2)Se_(2)Te_(5)(GST)in the terahertz(THz)regime.First,we experimentally show the reversible switching characteristic of GST on large areas by applying a single nanosecond laser pulse,which exhibits excellent contrast of THz properties in both states.Then,we present a multiplex metasurface scheme.In each metasurface,three sets of structures are adopted,in which two sets integrate GST.The effective structures can be reversely modulated by the amorphization and crystallization of GST.As a proof of concept,the dynamic beam splitter,bifocal metalens,dual-mode focusing optical vortex generators,and switchable metalens/focusing optical vortex generators are designed,fabricated,and experimentally characterized,and can be switched reversibly and repeatedly with the help of optical and thermal stimuli.Our scheme will pave the way toward the development of multifunctional and compact THz devices and may find use for applications in THz imaging,sensing,and communications. | SHOUJUN ZHANG XIEYU CHEN KUAN LIU HAIYANG LI YUEHONG XU XIAOHAN JIANG YIHAN XU QINGWEI WANG TUN CAO ZHEN TIAN | 2022 | Photonics Research2022，10，7： | 2 |
| 20 | Quadratic Stabilization of Switched Uncertain Linear Systems: A Convex Combination Approach显示文摘We consider quadratic stabilization for a class of switched systems which are composed of a finite set of continuoustime linear subsystems with norm bounded uncertainties. Under the assumption that there is no single quadratically stable subsystem, if a convex combination of subsystems is quadratically stable, then we propose a state-dependent switching law, based on the convex combination of subsystems, such that the entire switched linear system is quadratically stable. When the state information is not available, we extend the discussion to designing an outputdependent switching law by constructing a robust Luenberger observer for each subsystem. | Yufang Chang Guisheng Zhai Bo Fu Lianglin Xiong | 2019 | IEEE/CAA Journal of Automatica Sinica2019，6，5： | 2 |
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