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Rapid assembling organ prototypes with controllable cell-laden multi-scale sheets

Bio-Design and Manufacturing 2019年第1期2卷 1-9页

作者： Qing Gao Peng Zhao Ruijian Zhou Peng Wang Jianzhong Fu Yong He Slate Key Laboratory of Fluid Power and Mechatronic Systems. School of Mechanical Engineering. Zhejiang University. Hangzhou 310027. China Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province. School of Mechanical Engineering Zhejiang University Hangzhou 310027 China

A native organ has heterogeneous structures, sirength, and cell components. It is a big challenge to fabricate organ prototypes with controllable shapes, strength, and cells. Herein, a hybrid method is developed to fabricate organ prototypes with controlled cell deposition by integrating extrusion-based 3D printing, electrospinning, and 3D bioprinting. Multi-scale sheets were first fabricated by 3D printing and electrospinning;then, all the sheets were assembled into organ prototypes by sol-gel react io n duri ng bioprinting. With this method, macroscale structures fabricated by 3D printing ensure the customized structures and provide mechanical support, nanoscale structures fabricated by electrospinning offer a favorable environment for cell growth, and different types of cells with controllable densities are deposited in accurate locations by bioprinting. The results show that L929 mouse fibroblasts encapsulated in the structures exhibited over 90% survival within 10 days and maintai ned a high proliferation rate. Furthermore, the cells grew in spherical shapes first and then migrated to the nano scale fibers showing stretched morphology. Additionally, a branched vascular structure was successfully fabricated using the presented method. Compared with other methods, this strategy offers an easy way to simultancously realize the shape control, nanolibrous structures, and cell accurate deposition, which will have potemidi applications in tissue cngineering.

关键词： Organ prototypes 3D printing Electrospinning 3D bioprinting Multi-scale sheets

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FSCIL-EACA: Few-Shot Class-Incremental Learning Network Based on Embedding Augmentation and Classifier Adaptation for Image Classification

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Chinese Journal of Electronics 2024年第1期33卷 139-152页

作者： Ruru ZHANG Haihong E Meina SONG School of Computer Science Beijing University of Posts and Telecommunications Education Department Information Network Engineering Research Center Beijing University of Posts and Telecommunications

The ability to learn incrementally is critical to the long-term operation of AI systems. Benefiting from the power of few-shot class-incremental learning(FSCIL), deep learning models can continuously recognize new classes with only a few samples. The difficulty is that limited instances of new classes will lead to overfitting and exacerbate the catastrophic forgetting of the old classes. Most previous works alleviate the above problems by imposing strong constraints on the model structure or parameters, but ignoring embedding network transferability and classifier adaptation(CA), failing to guarantee the efficient utilization of visual features and establishing relationships between old and new classes. In this paper, we propose a simple and novel approach from two perspectives: embedding bias and classifier bias. The method learns an embedding augmented(EA) network with cross-class transfer and class-specific discriminative abilities based on self-supervised learning and modulated attention to alleviate embedding bias. Based on the adaptive incremental classifier learning scheme to realize incremental learning capability,guiding the adaptive update of prototypes and feature embeddings to alleviate classifier bias. We conduct extensive experiments on two popular natural image datasets and two medical datasets. The experiments show that our method is significantly better than the baseline and achieves state-of-the-art results.

关键词： Training Adaptation models Visualization Image recognition prototypes Self-supervised learning Power capacitors

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FGM-SPCL:Open-Set Recognition Network for Medical Images Based on Fine-Grained Data Mixture and Spatial Position Constraint Loss

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Chinese Journal of Electronics 2024年第4期33卷 1023-1033页

作者： Ruru ZHANG Haihong E Lifei YUAN Yanhui WANG Lifei WANG Meina SONG School of Computer Science Beijing University of Posts and Telecommunications Engineering Research Center of Information Networks Ministry of Education Hebei Eye Hospital

The current intelligent auxiliary diagnosis models all follow the closed-set recognition setting. After the model is deployed online, the input data is often not completely controlled. Diagnosing an untrained disease as a known category would lead to serious medical malpractice. Therefore, realizing the open-set recognition is significant to the safe operation of the intelligent auxiliary diagnosis model. Currently, most open-set recognition models are studied for natural images, and it is very challenging to obtain clear and concise decision boundaries between known and unknown classes when applied to fine-grained medical images. We propose an open-set recognition network for medical images based on fine-grained data mixture and spatial position constraint loss(FGM-SPCL) in this *** the fine graininess of medical images and the diversity of unknown samples, we propose a fine-grained data mixture(FGM) method to simulate unknown data by performing a mixing operation on known data to expand the coverage of unknown data difficulty levels. In order to obtain a concise and clear decision boundary, we propose a spatial position constraint loss(SPCL) to control the position distribution of prototypes and samples in the feature space and maximize the distance between known classes and unknown classes. We validate on a private ophthalmic OCT dataset, and extensive experiments and analyses demonstrate that FGM-SPCL outperforms state-of-the-art models.

关键词： Analytical models Fine-grained image recognition prototypes Aerospace electronics Spatial databases Robustness Data models

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Dual-Mode Resonant Sectorial Monopole Antenna with Stable Backfire Gain

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Chinese Journal of Electronics 2024年第6期33卷 1478-1486页

作者： Feiyan JI Heng ZHANG Xiuqiong XING Wenjun LU Lei ZHU Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Department of Electrical and Computer Engineering Faculty of Science and Technology University of Macau

A novel design approach to wideband, dual-mode resonant monopole antenna with stable, enhanced backfire gain is advanced. The sectorial monopole evolves from a linear, 0.75-wavelength electric prototype monopole under wideband dual-mode resonant operation. As theoretically predicted by the two resonant modes TE3/5,1and TE9/5,1within a 150° radiator, the operation principle is revealed at first. As have been numerically demonstrated and experimentally validated at 2.4-GHz band, the designed antenna exhibits a wide impedance bandwidth over 90.1%（i.e., 2.06–5.44 GHz）, in which the stable gain bandwidth in the backfire,-x-direction（θ = 90°, φ = 180°） with peak value of 3.2 dBi and fluctuation less than 3 dB is up to 45.3%（i.e., 3.74–5.44 GHz）. It is concluded that the stable wideband backfire gain frequency response should be owing to the high-order resonant mode in the unique sectorial monopole antennas.

关键词： Fluctuations Azimuth prototypes Metals Resonance Frequency measurement Broadband antennas Impedance Gain Wideband

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A Single Photon Counting Detector Based on One-Dimensional Vernier Anode

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Chinese Physics Letters 2010年第5期27卷 257-260页

作者：杨颢赵宝升盛立志李梅鄢秋荣刘永安 State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi'an 710119 Graduate University of Chinese Academy of Sciences Beijing 100049

The mathematical expression on decoding the one-dimensional （1D） Vernier anode is deduced theoretically, and the corresponding 1D-Vernier anode collector is developed. A photon counting imaging and detection system is constructed based on a 1D-Vernier anode detector and electronic readout subsystem. With wavelengths of 253.7nm from the mercury lamp as the ultraviolet emission source, the spatial resolution of the prototype is proved to be better than 100 μm along the x-direction in experiment.

关键词： PHOTON detectors ANODES MATHEMATICAL analysis IMAGING systems ULTRAVIOLET radiation prototypes ELECTRONIC apparatus & appliances

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Dual Radial-Resonant Wide Beamwidth Circular Sector Microstrip Patch Antennas

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Chinese Journal of Electronics 2023年第4期32卷 710-719页

作者： MAO Xiaohui LU Wenjun JI Feiyan XING Xiuqiong ZHU Lei Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Department of Electrical and Computer Engineering Faculty of Science and Technology University of Macau

In this article, a design approach to a radial-resonant wide beamwidth circular sector patch antenna is advanced. As properly evolved from a U-shaped d ipole, a prototype magnetic dipole can be fit in the radial direction of a circular sector patch radiator, with its length set as the positive odd-integer multiples of onequarter wavelength. In this way, multiple TM0m(m = 1,2,...) modes resonant circular sector patch antenna with short-circuited circumference and widened E-plane beamwidth can be realized by proper excitation and perturbations. Prototype antennas are then designed and fabricated to validate the design approach. Experimental results reveal that the E-plane beamwidth of a dual-resonant antenna fabricated on air/Teflon substrate can be effectively broadened to 128°/120°, with an impedance bandwidth of 17.4%/7.1%, respectively. In both cases, the antenna heights are strictly limited to no more than 0.03-guided wavelength. It is evidently validated that the proposed approach can effectively enhance the operational bandwidth and beamwidth of a microstrip patch antenna while maintaining its inherent low profile merit.

关键词： Geometry Patch antennas Perturbation methods prototypes Magnetic resonance Microstrip antennas Bandwidth

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The Process and Benefits of Developing Prototype Climate Services——Examples in China

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Journal of Meteorological Research 2020年第5期34卷 893-903页

作者： Chris D.HEWITT Nicola GOLDING Peiqun ZHANG Tyrone DUNBAR Philip E.BETT Joanne CAMP Timothy D.MITCHELL Edward POPE Met Office Exeter EX 13PBUK University of Southern Queensland Toowoomba QLD 4350Australia Beijing Climate Center/National Climate Center China Meteorological AdministrationBeijing 100081China

Changes in climate pose major challenges to society, and so decision-makers need actionable climate information to inform their planning and policies to make society more resilient to climatic changes. Climate services are being developed to provide such actionable climate information. The successful development and use of climate services benefits greatly from close engagement between developers, providers, and users of the services. The Climate Science for Service Partnership China(CSSP China) is a China–UK collaboration fostering closer engagement between climate scientists, providers of climate services, and users of climate services. We describe the process within CSSP China of co-developing climate services through trials with users to revise and improve a prototype. Examples are provided covering various scientific capabilities, user needs, and parts of China. The development process is yielding many benefits, such as increasing the engagement between providers and users, making users more aware of how climate information can be of use in their decision-making, giving the climate service providers a better understanding of the users’ requirements for climate information, and shaping future scientific research and development. In addition to the benefits, we also document some challenges that have emerged, along with ways of alleviating them. We have two key recommendations from our experiences: make the time and space for effective engagement between the users and developers of any climate service;bring the needs of the users in to the design and delivery of the climate service as early as possible and throughout the development cycle.

关键词： climate services prototypes user engagement

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A Novel Wideband Wilkinson Pulse Combiner with Enhanced Low Frequency Isolation

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Chinese Journal of Electronics 2023年第4期32卷 683-691页

作者： WANG Zitong WU Qi SU Donglin The School of Electronic and Information Engineering Beihang University

In this paper, a novel Wilkinson pulse combiner(WPC) is proposed for the combination of Gaussian pulse signals. The WPC requires a very wide bandwidth, small size and high port isolation. To improve the operating bandwidth, the design adopts the form of eight-section WPC. Eight capacitors are connected in series with the isolating resistors of each *** capacitive loading, isolation between WPC input ports is significantly improved at low frequency. Consequently, the operating bandwidth of WPC has been increased from 13:1 to 31:1. Compared with the conventional Wilkinson combiner with the same bandwidth, the proposed WPC reduces the size by 40%. In addition, all the ports are well impedance matched and the insertion loss in the operating frequency band is less than 0.5 dB. To verify the feasibility of the design, a prototype was fabricated and measured. Experiment shows that the novel WPC is more advantageous to generate dual-Gaussian pulse signals.

关键词： Resistors Current measurement Loading Capacitors prototypes Insertion loss Capacitance

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Design of Differential Multi-Point Feeding Dual-Polarized SISL Antenna Based on CM Analysis

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Chinese Journal of Electronics 2024年第5期33卷 1245-1252页

作者： Bin TANG Kaixue MA Eric Newton MORO Yu LUO Tianjin Key Laboratory of Imaging and Sensing Microelectronics Technology School of MicroelectronicsTianjin University

Dual-polarized antennas are required in the current mobile communication to increase the channel capacity and reducing multi-path effects. Utilizing characteristic mode(CM) analysis, this paper presents a five-patch substrate integrated suspended line(SISL) antenna with suppressed unwanted higher-order modes, and achieves an enhanced bandwidth by using differential multi-point feeding(MPF) systems. Compared to single-point feeding systems, the proposed dual-polarized SISL antenna with the MPF system demonstrates a bandwidth 1.87 times wider. The novel SISL feeding system incorporates two pairs of differentially-fed branch line feed structures. A prototype of the proposed differential-fed antenna is fabricated and measured, showing good agreement between simulated and measured results. The dual-polarization SISL antenna can achieve realized gain from 8.1 dBi to 10.8 dBi within a working frequency from 3.17 GHz to 3.61 GHz(12.98%). Moreover, utilizing low-cost substrates, the proposed SISL antenna has the potential for 5G applications.

关键词： Antenna measurements 5G mobile communication prototypes Bandwidth Directive antennas Mobile antennas Gain measurement

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NGD Analysis of Defected Ground and SIW-Matched Structure

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Chinese Journal of Electronics 2023年第2期32卷 343-352页

作者： GU Taochen WAN Fayu GE Junxiang Lalléchère Sébastien Rahajandraibe Wenceslas Ravelo Blaise Nanjing University of Information Science & Technology (NUIST) Université Clermont Auvergne (UCA) CNRS SIGMA Clermont Aix-Marseille University CNRS University of Toulon

A bandpass negative group delay(NGD)passive circuit based on defect ground structure(DGS)and substrate integrated waveguide(SIW)-matched is developed in the paper. The NGD DGS topology is originally built with notched cells associated with self-matched substrate waveguide elements. The DGS design method is introduced as a function of the geometrical notched and SIW via elements. Then, parametric analyses based on full wave 3-D electromagnetic S-parameter simulations were considered to investigate the influence of DGS physical size effects. The design method feasibility study is validated with fully distributed microstrip circuit prototype. Significant bandpass NGD function performances were validated with 3-D simulations and measurements with-1.69 ns negative group delay value around 2 GHz center frequency over 33.7 MHz NGD bandwidth. Insertion loss is 4.37 d B, and reflection loss reaches 41.5 d B.

关键词： Solid modeling prototypes Electromagnetic waveguides Reflection Passive circuits Delays Frequency measurement

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