检索结果-南通市图书馆

Multiplexing metal grating coupler based on MIM structure

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2025年

作者： LIU Yang LIU Fei MA Yunxia ZHANG Ailing Engineering Research Center of Communication Devices and technology， Ministry of Education， tianjin key laboratory of Film Electronic and Communication Devices， School of Integrated Circuit science and Engineering， tianjin University of technology

We propose and numerically investigate a multiplexing metal grating coupler based on metal/insulator/metal （MIM） structure. The coupler consists of gold grating/silicon/gold layers， which combines with MIM waveguide， concurrently achieving path multiplexing and wavelength multiplexing through TMnmodes coupling. In visible light band， TM waves are coupled to the upper surface of gold plate， and the coupling efficiency reaches maximum of 31.67% at wavelength of 736 nm. In near infrared and mid infrared bands， TM waves are coupled into MIM waveguide， and the coupling efficiency reaches maximum of 53.57% at wavelength of 2550 nm. There can be four modes of TM0， TM1， TM2and TM3simultaneously in MIM waveguide， which are excited at different wavelengths. The preparation process of the structure designed in this article is simple， with dimensions at the micrometer level， easy to be integrated， and can be applied to be integrated optical circuits.

关键词：

Hyperbolic cosine transformer for LiDAR 3D object detection

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2025年

作者： Tong Jigang Yang Fanhang Yang Sen Du Shengzhi tianjin key laboratory for Control Theory & Applications in Complicated Systems and Intelligent Robot laboratory， tianjin University of technology Department of Electrical Engineering， Tshwane University of technology

Recently， Transformer has achieved great success in computer vision. However， it is constrained because the spatial and temporal complexity grows quadratically with the number of large points in 3D object detection applications from point clouds. Previous point-wise methods are suffering from time consumption and limited receptive fields to capture information among points. To address these limitations， we propose the cosh-attention， which reduces the computation complexity of space and time from the quadratic order to linear order with respect to the number of points. In the cosh-attention， the traditional softmax operator is replaced by non-negative ReLU activation and hyperbolic-cosine-based operator with re-weighting mechanism. Then based on the key component， cosh-attention， we present a two-stage hyperbolic cosine transformer (ChTR3D) for 3D object detection from point clouds. It refines proposals by applying cosh-attention in linear computation complexity to encode rich contextual relationships among points. Extensive experiments on the widely used KITTI dataset and Waymo Open Dataset demonstrate that， compared with vanilla attention， the cosh-attention significantly improves the inference speed with competitive performance. Experiment results show that， among two-stage state-of-the-art methods using point-level features to refine proposals， the proposed ChTR3D is the fastest one.

关键词：

High sensitivity dual polarization four channels surface plasmon resonance refractive index sensor with wide detection range and high linearity based on photonic crystal fiber

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2025年

作者： CUI Nan PAN Honggang ZHANG Ailing ZHAO Zihong CHEN Zhipan ZHANG Bo tianjin key laboratory of Film Electronic and Communication Devices， Engineering Research Center of Optoelectronic Devices and Communication technology， Ministry of Education， School of Integrated Circuit science and Engineering， tianjin University of technology

In this paper， we propose and numerically characterize the optical characteristics of a high sensitivity dual polarization four channels surface plasmon resonance refractive index sensor with wide detection range and high linearity based on photonic crystal fiber （PCF）. Four light transmission channels are constructed by using big air holes. The small rectangular air hole in the center of the fiber core is used to add asymmetry. We use gold plasma material to achieve better sensing performance. A thin film of TiO2is placed on the PCF surface， which assists gold in the adhesion on PCF. The maximum wavelength sensitivity of the sensor can reach 20000 nm/RIU in both x and y polarization modes. While the maximum wavelength resolution of the sensor is 5×10-6RIU. The average wavelength sensitivity reached 15900nm/RIU and 15800nm/RIU in x and y polarization mode. The sensor features R2=0.9969 / R2=0.9966 high linear performance in x and y polarization mode and the maximum FOM values 509.13 RIU-1/ 489.63 RIU-1in x and y polarization mode. Besides the sensor’s detection range is 1.26-1.36， which is a wide refractive index detection range. The sensor has a wide range of applications in biomedical and other fields.

关键词：

Design of high performance multi-notch filters based on photonic crystal nanorod flower-shaped resonators

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2025年

作者： YAN WEI ZHANG SHUANGGEN ZHANG WEIWEI tianjin key laboratory of Film Electronic and Communication Devices， Engineering Research Center of Optoelectronic Devices and Communication technology， Ministry of Education， School of Integrated Circuit science and Engineering， tianjin University of technology

Photonic crystal notch filter plays a vital role in photonics applications which can selectively attenuate the unwanted interference. However， it remains challenging to achieve high efficiency and is generally limited to the single notch performance. Here， we demonstrated a high efficient all-silicon multi-notch filter scheme utilizing photonic crystal nanorod flower-shaped resonators. Based on the single resonant cavity， the dielectric columns can be introduced to create the intracavity asymmetry achieving double notch， meanwhile by adding the certain scattering nanorods to trap light efficiently， it can also obtain triple notch. The results emanate that the transmission and the Q of single notch up to 2.6% and 16209.4， double notch 0.5%， 0.1% and 12371.7，13934.5， triple notch 0.2%， 0.5%， 2.3%， 2312.9， 2062.8， 2327.4 can be achieved， respectively. The proposed high efficient multi-notch filters could potentially catalyze advancements in filter technology within the realm of silicon photonics applications and optical communication.

关键词：

Multicomponent polymerization of elemental sulfur,difluoromethylene phosphobetaine and aryl silyl ethers toward aromatic poly(O,O′-monothiocarbonate)s

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China Chemistry 2025年

作者： Yongjiang Yu Rongrong Hu Ben Zhong Tang State key laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology School of science and Engineering Shenzhen Institute of Aggregate Science and Technology The Chinese University of Hong Kong AIE Institute

Polythiocarbonates with similar structures to polycarbonates, have emerged as a group of promising sulfur-containing polymers with a range of practical applications, taking advantages of their excellent optical properties, good thermal stability and filmforming ability, and so on. However, the synthesis of polythiocarbonates generally suffered from mixed isomeric structures of repeating units, and hazardous sulfur-containing reagents. In this work, an efficient multicomponent reaction of elemental sulfur,difluoromethylene phosphobetaine（PDFA）, and aryl silyl ethers was designed with the assistance of organic base 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene（MTBD） to produce 12 kinds of O,O′-monothiocarbonate compounds in up to 93% yields,taking advantages of the unique chemical property of difluorocarbene, and the deprotection of silyl group by F-generated from PDFA. Most importantly, the MTBD-assisted multicomponent polymerization of bis（aryl silyl ether）s, elemental sulfur, and PDFA was developed, affording 12 kinds of poly（O,O′-monothiocarbonate）s with well-defined structures, high Mws of up to16900 g/mol and high yields（up to 99%）. These poly（O,O′-monothiocarbonate）s possessed good film-forming properties and thermal stability, high light refractive indices and transmittance. The facile synthesis of these polymonothiocarbonates might pave the way for the development of promising sulfur-containing polymer materials.

关键词：

Cooperative output regulation of heterogeneous directed multi-agent systems: a fully distributed model-free reinforcement learning framework

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China(information sciences) 2025年

作者： Xiongtao SHI Yanjie LI Chenglong DU Huiping LI Chaoyang CHEN Weihua GUI Guangdong key laboratory of Intelligent Morphing Mechanisms and Adaptive Robotics School of Mechanical Engineering and Automation Harbin Institute of Technology (Shenzhen) School of Automation Central South University School of Marine science and technology Northwestern Polytechnical University School of information and Electrical Engineering Hunan University of Science and Technology

In this paper, the cooperative output regulation (COR) problem of a class of unknown heterogeneous multi-agent systems (MASs) with directed graphs is studied via a model-free reinforcement learning (RL) based fully distributed eventtriggered control (ETC) strategy. First, we consider the scenario that the exosystem is accessible globally to all agents, an internal model-based augmented algebraic Riccati equation (AARE) is constructed, and its solution is learned by the proposed model-free RL algorithm via online input-output data. Further, for the scenario that the exosystem is accessible only to its adjacent followers, the distributed observers are designed for each agent to get the state of the exosystem, and an internal modelbased fully distributed adaptive ETC protocol is then synthesized to construct the corresponding AARE, and the feedback gain matrix is learned in a model-free fashion. The model-free RL-based control protocol proposed in this paper can not only remove the prior knowledge of agents’ dynamics, but also release the dependence on global information by the adaptive event-triggered mechanism (ETM) and the new graph-based Lyapunov function. Finally, simulation results are illustrated to show the feasibility and effectiveness of the proposed control scheme.

关键词：

Design high-performance narrowband emitters for blue light-emitting diodes through manipulating resonance structure of aromatic heterocycles

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China Chemistry 2025年

作者： Yue Yu Lei Xu Wenle Tan Yuyu Pan Jiyin Xiao Bohan Wang Guangjun Tian Yuguang Ma Lei Ying Institute of Polymer Optoelectronic Materials and Devices Guangdong Basic Research Center of Excellence for Energy and Information Polymer Materials State Key Laboratory of Luminescent Materials and Devices South China University of Technology School of Petrochemical Engineering Shenyang University of Technology key laboratory for microstructural Material Physics of Hebei Province School of Science Yanshan University

Narrowband light-emitting materials play critical roles in improving the color gamut and energy consumption of electroluminescence. Herein we demonstrated that by regulating the ground state resonance structure form of emitters with polycyclic aromatic heterocycles, the high-energy vibration of the C–C bond can be effectively suppressed, resulting in narrow emission like classical cyanine dyes. The designed compounds consist of twist and planar conformation, while having differences in the orientation of the positioning electron-donating(nitrogen) and electron-accepting(carbonyl) groups in the polycyclic aromatic hydrocarbon skeleton. The resulting compound Ac-Ph-Ac with a dominated zwitterionic resonance structure exhibits a relatively wide electroluminescent profile with the full width at half maximum(FWHM) of 42 nm and moderate device performance. In contrast, the “soliton transition” of 2AcPh based on the cyanine limit character effectively suppresses C–C stretching vibration in the polycyclic aromatic heterocycle skeleton, leading to a narrow electroluminescent profile with FWHM of 30 nm(0.16 eV)associated with an impressively high external quantum efficiency of 28.52%, which is among the highest efficiencies of so far reported non-sensitized organic light-emitting diodes.

关键词：

A reduction scheme of PAPR in CO-OFDM system using time-delay neural networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2025年

作者： TONG Zhengrong LIU Zhihong WANG Hao ZHANG Weihua ZHANG Tianhao JIA Qiqi tianjin key laboratory of Thin Film Electronics and Communication Devices， Engineering Research Center for Optoelectronic Devices and Communication technology of the Ministry of Education， School of Integrated Circuit science and Engineering， tianjin University of technology

An iterative partial transmission sequence （IPTS） cascading time-delay neural network （TDNN） scheme is proposed to reduce peak-to-average power ratio （PAPR） in the coherent optical orthogonal frequency division multiplexing （CO-OFDM） systems. The IPTS algorithm further reduces computational complexity based on the partial transmission sequence （PTS） algorithm. TDNN is trained by the iterative clipping filtering （ICF） method. Simulation results show that the proposed scheme achieves a PAPR reduction of 5.84 dB when complementary cumulative distribution function （CCDF） is 10-4and an extra transmission distance of 200 km for 10-3bit error rate （BER） compared to the original signals.

关键词：

Composite-mask GAN based on refined optical flow and disparity map for SLAM visual odometry

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2025年

作者： JI Yuehui JIANG Jingwei LIU Junjie SONG Yu GAO Qiang School of Electrical Engineering and Automation， tianjin University of technology tianjin key laboratory of Control Theory and Application for Complex Systems

Although deep learning methods have been widely applied in slam visual odometry over the past decade with impressive improvements， the accuracy remains limited in complex dynamic environments. In this paper， a composite mask-based generative adversarial network is introduced to predict camera motion and binocular depth maps. Specifically， a perceptual generator is constructed to obtain the corresponding parallax map and optical flow from between two neighboring frames. Then， an iterative pose improvement strategy is proposed to improve the accuracy of pose estimation. Finally， a composite mask is embedded in the discriminator to sense structural deformation in the synthesized virtual image， thereby increasing the overall structural constraints of the network model， improving the accuracy of camera pose estimation， and reducing drift issues in the Visual Odometer. Detailed quantitative and qualitative evaluations on the KITTI dataset show that the proposed framework outperforms existing conventional， supervised learning and unsupervised depth VO methods， providing better results in both pose estimation and depth estimation.

关键词：