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European Conference on Antennas and Propagation: EuCAP 2006

作者： Schaubert, D.H. Kasturi, S. Elsallal, M.W. Van Cappellen, W. Antennas and Propagation Laboratory Center for Advanced Sensor and Communication Antennas University of Massachusetts Amherst MA 01002 United States Advanced Technology Center Rockwell Collins Cedar Rapids IA 52498 United States ASTRON 7990 AA Dwingeloo Netherlands

ISBN: (纸本)9290929375

Arrays of Vivaldi tapered slot antennas have become an established technology for wide bandwidth scanning arrays. Antenna bandwidths of 10:1 with scanning to 45° are achievable. To design the array, mutual coupling must be properly included and, in fact, utilized. Therefore, problems have arisen when these arrays are fabricated as independent subarrays without electrical contact between adjacent elements or subarrays. Nevertheless, it is highly beneficial to consider arrays with gaps because it is much easier to fabricate and to repair the array if the elements can be inserted or removed individually or in small groups. This paper presents results of some recent studies of Vivaldi antenna arrays wherein there are gaps between elements and/or subarrays. Such gaps between all elements of an array usually produce severe impedance anomalies that disrupt the operating band of the array. Employing mirror symmetries in arrays of Balanced Antipodal Vivaldi Antennas has eliminated these anomalies over a substantial portion of the operating frequency range with no apparent detrimental effects.

关键词： Antenna arrays

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Manipulating Zr/Ti ratio based on phase diagram for large electrocaloric effects with multiple target operation temperatures in PLZT ceramics

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Journal of advanced Ceramics 2024年第9期13卷 1422-1431页

作者： Junjie Li Ruowei Yin Zhe Xiong Yizheng Bao Xing Zhang Wenjuan Wu Lezhong Li Yang Bai Sichuan Province Key Laboratory of Information Materials and Devices Application College of Optoelectronic Engineeringand Chengdu IC Valley Industrial CollegeChengdu University of Information TechnologyChengdu 610225China Beijing Advanced Innovation Center for Materials Genome Engineering and Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Chengdu Hongming Electronics Co. Ltd.Chengdu 610199China Key Laboratory of Inorganic Functional Materials and Devices Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 201800China Sichuan Meteorological Optoelectronic Sensor Technology and Application Engineering Research Center Chengdu University of Information TechnologyChengdu 610225China

Ferroelectric phase transition has been identified as a promising avenue for designing high-performanceelectrocaloric materials for zero-emission and solid-state refrigeration. However, extensive research has been limited todeveloping ferroelectric materials with large electrocaloric effects near room temperature, preventing them from meetingdiverse refrigeration requirements. In this study, by leveraging the room-temperature phase diagram of the (PbLa)(ZrTi)O_(3)solution, we prepared a series of Pb_(0.775)La_(0.15)Zr_(x)Ti_(1−x)O_(3) bulk ceramics spanning the ferroelectric and relaxor ferroelectricphase regions. This enabled the attainment of various phase transition features and temperatures. Finally, largeelectrocaloric effects, coupled with adjustable operation temperatures ranging from 150 to −45℃, are successfullyachieved through manipulation of the Zr/Ti ratio. This comprehensive range of operation temperatures effectively addressesdiverse refrigeration application requirements, ranging from industrial equipment to freezer cabinets. This work not onlyunderscores the expansion of the electrocaloric refrigeration application domain but also proposes a material designstrategy tailored to meet these evolving demands.

关键词： electrocaloric effect phase transition phase diagram ferroelectric ceramics

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Design of temperature compensation for silicon-sapphire pressure sensor

Design of temperature compensation for silicon-sapphire pres...

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2017 IEEE International Conference on Imaging Systems and Techniques, IST 2017

作者： Manguo, Huang Defeng, Liu Chao, Lu Zhanshe, Guo Xin, Li Advanced Sensor Technology Center AVIC Beijing Changcheng Aeronautic Measurement Control Technology Research Institute Aviation Key Laboratory of Science and Technology Special Condition Monitoring Sensor Technology Beijing China School of Instrument Science and Opto-electronics Engineering State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing China

ISBN: (纸本)9781538616208

In order to solve the problem that the temperature drift of the silicon-on-sapphire pressure sensor is too large to reduce the accuracy of pressure measurement at high temperature, a temperature compensation scheme based on a single chip is proposed. The temperature of the working environment is obtained by a PT100, and integrated with the output of pressure sensor to calculate the compensated pressure sensor. Problems of power supply and signal acquisition are solved by the high precision, low drift voltage and current references, programmable amplifiers and high precision ADCs on chip. According to the working characteristics of the silicon-on-sapphire pressure sensor, an efficient temperature compensation algorithm is designed, and written to the on-chip ARM processor. The experimental results show that the maximum measurement error of pressure in the temperature range of -20∼250°C and measurement range of 0∼28 MPa is 8.37%FS before compensation and reduced to 0.3%FS after compensation. The accuracy of the sensor is greatly improved by the compensation system. © 2017 IEEE.

关键词： Pressure sensors

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Manipulating functional groups between polyvinylidene difluoride and nanoparticles for high-performance triboelectric nanogenerator

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Nano Research 2023年第9期16卷 11855-11861页

作者： Zekun Li Lu Zhang Lihao Guo Wenwen Hu Aifang Yu Junyi Zhai CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 101400China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing 100049China School of Advanced Materials and Nanotechnology Interdisciplinary Research Center of Smart SensorsXidian UniversityXi’an 712000China School of Aerospace Science and Technology Xidian UniversityXi’an 712000China

Interface functional groups play an essential role in regulating the electrical properties of bulk *** this work,we designed a novel strategy to explore a new way to enhance triboelectric performance by regulating the functional groups between nano-fillers and polymer matrix without obvious changes in the dielectric *** silica nanoparticles(SNPs)modified perfluoro-silane coupling agents(PFSCAs)with different chain lengths were added to the polyvinylidene difluoride to regulate the transferred charge density(TCD)of triboelectric nanogenerators(TENGs).When the doping concentration of perfluorodecyl modified SNPs is 2.25 wt.%,the nanocomposite film based TENG exhibits the maximum TCD of 166μC/m^(2)and power density of 3.12 W/m^(2)which are 6 times and 39 times as big as those of pure polyvinylidene difluoride(PVDF)*** charge accumulation and decay process show that interface functional groups dominate the performance of ***,a Fermi level model is proposed and why the TCD could be regulated by the concentration of nanoparticles in bulk materials is *** work provides a new concept for understanding the performance of TENG independent dielectric constant and points out a new direction for enhancing TENG’s performance,since wealthy functional groups with selectivity are applicable.

关键词： triboelectric nanogenerators functional groups surface modification interfacial regulation transferred charge density

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Brightness and Lifetime Improved Light-Emitting Diodes from Sr-Doped Quasi-Two-Dimensional Perovskite Layers

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Tsinghua Science and technology 2023年第1期28卷 131-140页

作者： Dan Chen Taoran Liu Yuhua Zuo Chuanbo Li Jun Zheng Zhi Liu Baoyu Liu Buwen Cheng State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Science Minzu University of ChinaBeijing 100081China Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Key Laboratory for SensorMOE Key Laboratory for Modern Measurement and Control Technologyand Beijing Information Science and Technology UniversityBeijing 100101China

Green Perovskite Light-Emitting Diodes(PeLEDs)have attracted wide attention for full spectrum ***,the inferior film morphology and luminescence property of quasi-two-dimensional(quasi-2D)perovskite layers limit the photoelectric property of the *** this paper,the effect of strontium(Sr)doped in quasi-2D perovskite layers is investigated to obtain a high-quality active *** morphologies and optical properties of Sr-doped quasi-2D perovskite films with different concentrations are *** the addition of strontium,more low-dimensional-layer perovskite phases(n D 2 and n D 3)appear in quasi-2D perovskite films,providing efficient intraband carrier funneling pathway and facilitating radiative *** photoluminescence(PL)peak intensity of optimized Sr-doped quasi-2D perovskite layers increases 50%compared with the non-strontium ***,green PeLEDs based on a Sr-doped quasi-2D perovskite layer reach a maximum luminance(Lmax)of 2943.77 cd/m^(2),which is three times of the control *** electroluminescence(EL)peaks of Maximum External Quantum Efficiency(MEQE)and Lmax of Sr-doped PeLEDs exhibite a slight shift,indicating the excellent stability and performance of Sr-doped *** optimized device can continuously operate for 360 s at MEQE driving voltage,resulting in a half-lifetime of60 s,which is 3-fold greater than that of the control PeLEDs.

关键词： Perovskite Light-Emitting Diodes(PeLED) Sr-doped brightness improved lifetime increased

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Parameter estimation in n-dimensional massless scalar field

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Chinese Physics B 2024年第3期33卷 231-237页

作者：杨颖荆继良 Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials School of Physics and ElectronicsHunan University of Science and TechnologyXiangtan 411201China Department of Physics Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Educationand Synergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081Chin

Quantum Fisher information(QFI)associated with local metrology has been used to parameter estimation in open quantum *** this work,we calculated the QFI for a moving Unruh-DeWitt detector coupled with massless scalar fields in n-dimensional spacetime,and analyzed the behavior of QFI with various parameters,such as the dimension of spacetime,evolution time,and Unruh *** discovered that the QFI of state parameter decreases monotonically from 1 to 0 over ***,we noted that the QFI for small evolution times is several orders of magnitude higher than the QFI for long evolution *** also found that the value of QFI decreases at first and then stabilizes as the Unruh temperature *** was observed that the QFI depends on initial state parameterθ,and Fθis the maximum forθ=0 orθ=π,Fφis the maximum forθ=π/*** also obtain that the maximum value of QFI for state parameters varies for different spacetime dimensions with the same evolution time.

关键词： quantum Fisher information parameter estimation open quantum systems

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Interface Modification of TiO_(2)Electron Transport Layer with PbCl_(2)for Perovskiote Solar Cells with Carbon Electrode

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Tsinghua Science and technology 2022年第4期27卷 741-750页

作者： Abolfazl Amraeinia Yuhua Zuo Jun Zheng Zhi Liu Guangze Zhang Liping Luo Buwen Cheng Xiaoping Zou Chunbo Li Key Laboratory on Integrated Optoelectronics Institute of SemiconductorChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Key Laboratory for SensorMOE Key Laboratory for Modern Measurement and Control TechnologyBeijing Information Science and Technology UniversityBeijing 100101China School of Science Minzu University of ChinaBeijing 100081China

Perovskite Solar Cells(PSCs)have attracted considerable attention because of their unique features and high ***,the stability of perovskite solar cells remains to be *** this study,we modified the TiO_(2)Electron Transport Layer(ETL)interface with PbCl_(2).The efficiency of the perovskite solar cells with carbon electrodes increased from 11.28%to 13.34%,and their stability obviously *** addition of PbCl_(2)had no effect on the morphology,crystal structure,and absorption property of the perovskite absorber ***,it affected the band energy level alignment of the solar cells and accelerated the electron extraction and transfer at the interface between the perovskite layer and the ETL,thus enhancing the overall photovoltaic *** interfacial modification of ETL with PbCl_(2)is a promising way for the potential commercialization of low-cost carbon electrode-based perovskite solar cells.

关键词： Perovskite Solar Cell(PSC) Electron Transport Layer(ETL) electron and hole recombination modification stability

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A Web-Based Campus Navigation System with Mobile Augmented Reality Intervention

A Web-Based Campus Navigation System with Mobile Augmented R...

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2021 Asian Conference on Intelligent Computing and Data Sciences, ACIDS 2021

作者： Nordin, Noradila Markom, Marni Azira Suhaimi, Farhana Aqilah Ishak, Syaimaa' School of Computing Universiti Utara Malaysia SintokKedah06010 Malaysia Advanced Sensor Technology Center of Excellence Universiti Malaysia Perlis Kampus Pauh Putra Perlis Arau02600 Malaysia

In this era of information technology, the introduction of new and greatly improved technologies is becoming vital especially with the progressive development of computing power to fulfill current technological needs. Augmented Reality (AR) is a part of the emerging technologies that are gaining great attention and interest with new and better innovations being developed. AR is an immersive technology where it complements real-world objects together with computer-generated objects to give more details and meaning to the objects in the real world. AR has been successfully growing nowadays in many industries, mainly in gaming and entertainment, education and navigation. However, AR has not been standardized and to be widely used in navigation systems even though there are many applications developed for this purpose. This paper proposed a web-based AR-UUM Campus Navigation System using ARToolKit, that is accessible via mobile devices that uses AR to overlay the information as images of the searched location on campus, especially for indoor navigations for lecture halls, tutorial rooms, laboratories, and offices which rarely are covered by the normal maps. Based on the respondents' evaluation, they managed to successfully interact with the AR-UUM Campus Navigation System, however, some improvements are required in terms of the functions expected from the system. Nevertheless, the use of AR in a navigation system shows promising results and has the potential to be widely used due to high interest in augmented reality. © Published under licence by IOP Publishing Ltd.

关键词： Augmented reality

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Recent development of implantable and flexible nerve electrodes

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Smart Materials in Medicine 2020年 1卷 131-147页

作者： Shi, Yue Liu, Ruping He, Liang Feng, Hongqing Li, Ye Li, Zhou Beijing Institute of Graphic Communication Beijing102600 China CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and Sensor Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of Sciences Beijing100083 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China

Implantable electrical devices offer a variety of potential diagnostic options and treatments in different medical fields. Especially in the absence of specific drugs, the implantable nerve electrodes (INEs) are one of the main treatments for neurological diseases such as epilepsy, Parkinson's disease, Alzheimer's disease, etc. INEs are helpful in studying and regulating nervous system via recording nerve electrical signals or stimulating nerve tissue, but the mechanical mismatch between rigid electrode and soft biological tissue is a critical challenge for long-term implantation. The advances in micromachining technologies and materials have greatly promoted the development of INEs, such as enhanced biocompatibility, reduced foreign body reactions, and structural innovation. In particular, the mechanical performances of flexible implantable electrode and soft biological tissue matched better with less tissue damage. In this review, the implantable flexible nerve electrodes (IFNEs) based on functionalized substrates, intelligent electrodes, and innovative structures are elaborated and discussed. We summarized their various applications in neural prosthesis and neural signal recording. We also discussed the questions and possible methods for developing future IFNEs in the perspective. © 2020 The Authors

关键词： Electrodes

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An Improved Fused EM Algorithm for PET Image Reconstruction

An Improved Fused EM Algorithm for PET Image Reconstruction

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2020 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2020

作者： Zhu, Shanshan Liang, Dong Liu, Xin Zheng, Hairong Yang, Yongfeng Hu, Zhanli Hubei Key Laboratory of Broadband Wireless Communication and Sensor Networks Wuhan University of Technology Wuhan430070 China The Lauterbur Research Center for Biomedical Imaging Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China

ISBN: (纸本)9781728176932

This paper presents an improved PET image reconstruction method based on iterative method. Emission tomography (PET) is an advanced clinical imaging technique in nuclear medicine. PET can be specifically injected with a radioactive tracer to detect activity at the molecular level in the tissue, but, the tracer injection poses a potential radiation risk to the patient. However, the limitation of injection dose and collection time leads to the relatively poor spatial resolution and high noise level of positron emission imaging, which makes the quantitative interpretation of PET images difficult. Therefore, the research and development of new low-dose PET imaging methods can not only ensure the quality of PET imaging but also reduce the harmful radiation dose, which has important scientific significance and application prospect in the field of medical diagnosis. The reconstruction framework proposed in this paper is based on the traditional maximum likelihood expectation maximization (ML-EM) method and the bootstrapping filter method. First, the ML-EM method is used to directly reconstruct an image, which is used as a guide. Secondly, perform Anscombe transform and filter on the projection data, followed by inverse transformation. The processed data was also reconstructed with ML-EM, and the resulting image was used as the guide image. The two images generated in the first two steps were fed into the guide filter to obtain the final image. For simplicity, the proposed improved fusion EM method is named IF-EM. In this paper, we present qualitative and quantitative results from simulation data, which show that the proposed method has good statistical performance. © 2020 IEEE

关键词： Image reconstruction

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