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Polarized imaging dynamic light scattering for simultaneous measurement of nanoparticle size and morphology

Particuology 2024年第2期85卷 213-223页

作者： Bingyao Wang Tianyi Cai Xiaoshu Cai Wu Zhou zeqi liu Schoolof Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai200093China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093China Jiaxing MeaParTech Instrument Technology Co. LtdZhejiang314000China

The performance of nanoparticles is often affected by particle size and morphology.Currently,electron microscopy or atomic force microscopy is typically utilized to determine the size and morphology of nanoparticles.However,there are issues such as difficult sample preparation,long processing times,and challenges in quantitative characterization.Therefore,it is of great significance to develop a fast,accu-rate,and statistical method to measure the size and morphology of nanoparticles.In this study,a new method,called polarized imaging dynamic light scattering(PIDLS),is proposed.The nanoparticles are irradiated with a vertical linearly polarized laser beam,and a polarization camera collected the dynamic light scattering images of particles at four different polarization directions(0°,45°,90°,and 135°)at a scattering angle of 90°.The average particle size and distribution are obtained using the imaging dy-namic light scattering method at 0°polarization direction,and the morphology of the particles is ob-tained based on the depolarization patterns of the scattered light.The optical sphericityΦis defined based on the degree of linear polarization(DoLP).It is also implemented for the quantitative evaluation of the sphericity of the nanoparticles,including spherical,octahedral,nanoplate,nanorod,and linear ones.Together with the Poincarésphere parameterψ,the morphology of the nanoparticles can be roughly identified.In addition,PIDLS enables the measurement of particle size and morphology distributions simultaneously for evaluating the uniformity of particles.The effectiveness of PIDLS is verified by the measurement of five kinds of industrial titanium dioxide as well.

关键词： Imaging dynamic light scattering Polarized light scattering Non-spherical nanoparticles Morphology Online measurement

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Equalization Reconstruction Algorithm Based on Reference Signal Frequency Domain Block Joint for DTMB-Based Passive Radar

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Journal of Beijing Institute of Technology 2024年第1期33卷 41-53页

作者： Shuai Ma zeqi Yang Hua Zhang Yiheng liu Xiaode Lyu Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China National Key Laboratory of Microwave Imaging Technology Beijing 100190China School of Electronic Electrical and Communication Engineering University of Chinese Academy of SciencesBeijing 100049China.

Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small(LSS)target detection,a novel frequency domain block joint equalization algorithm is presented in this article.From the DTMB signal frame structure and channel multipath transmission characteristics,this article adopts a unconventional approach where the delay and frame structure of each DTMB signal frame are reconfigured to create a circular convolution block,facilitating concurrent fast Fourier transform(FFT)calculations.Following equalization,an inverse fast Fourier transform(IFFT)-based joint output and subsequent data reordering are executed to finalize the equalization process for the DTMB signal.Simulation and measured data confirm that this algorithm outperforms conventional techniques by reducing signal errors rate and enhancing real-time processing.In passive radar LSS detection,it effectively suppresses multipath and noise through frequency domain equalization,reducing false alarms and improving the capabilities of weak target detection.

关键词： passive radar frequency domain equalization reference signal reconstruction digital terrestrial multimedia broadcasting(DTMB)

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A Novel Clutter Suppression Algorithm for Low-Slow-Small Targets Detecting Based on Sparse Adaptive Filtering

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Journal of Beijing Institute of Technology 2024年第1期33卷 54-64页

作者： zeqi Yang Shuai Ma Ning liu Kai Chang Xiaode Lyu Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China National Key Laboratory of Microwave Imaging Technology Beijing 100190China School of Electronic Electrical and Communication Engineering University of Chinese Academy of SciencesBeijing 100049China Northern Institute of Electronic Equipment Beijing 100083China

Passive detection of low-slow-small(LSS)targets is easily interfered by direct signal and multipath clutter,and the traditional clutter suppression method has the contradiction between step size and convergence rate.In this paper,a frequency domain clutter suppression algorithm based on sparse adaptive filtering is proposed.The pulse compression operation between the error signal and the input reference signal is added to the cost function as a sparsity constraint,and the criterion for filter weight updating is improved to obtain a purer echo signal.At the same time,the step size and penalty factor are brought into the adaptive iteration process,and the input data is used to drive the adaptive changes of parameters such as step size.The proposed algorithm has a small amount of calculation,which improves the robustness to parameters such as step size,reduces the weight error of the filter and has a good clutter suppression performance.

关键词： passive radar interference suppression sparse representation adaptive filtering

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A novel Tb^(3+) and Eu^(3+) co-doped dual-emitting phosphate K_(3)SrBi(P_(2)O_(7))_(2) phosphor for application in FIR thermometers

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Journal of Rare Earths 2024年第3期42卷 455-463,I0001页

作者： Baochen Wang Shifeng Sun zeqi Li Zongwang Li Weiwei Lin Chao Zeng Yan-gai liu Ruiyu Mi School of Chemical and Environmental Engineering Anhui Polytechnic UniversityWuhu241000China State-Province Joint Engineering Laboratory of Zeolite Membrane Materials Key Lab of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of EducationInstitute of Advanced MaterialsCollege of Chemistry and Chemical EngineeringJiangxi Normal UniversityNanchang330022China Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes National Laboratory of Mineral MaterialsSchool of Materials Science and TechnologyChina University of GeosciencesBeijing100083China

Rare earth co-doped phosphor for fluorescence intensity ratio(FIR) thermometer has gained increasing attention in recent years. Herein, the novel Tb^(3+)and Eu^(3+)co-doped K_(3)SrBi(P_(2)O_(7))_(2)(KSBP) phosphate phosphors were reported. The crystal structure of the title phosphor was determined using Rietveld refinement and proved to have a three-dimensional structure. The time-resolved spectroscopy reveals that there is almost no energy transfer between Tb^(3+)and Eu^(3+). More importantly, Tb^(3+)and Eu^(3+)emissions show different thermal quenching behaviors, which claims the potential of this material for application in optical thermometer. The FIR of the typical KSBP:0.02Tb^(3+),0.04Eu^(3+)sample demonstrates a polynomial relationship as a function of temperature and the absolute and relative sensitivity are0.025 K^(-1) and 0.59%/K, respectively. In general, our study reports a novel and potential KSBP:Tb^(3+),Eu^(3+)phosphate phosphor that is promising for use in high-sensitive FIR thermometers.

关键词： Phosphor Thermometer Fluorescence intensity ratio Thermal stability Rare earths

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Particle manipulation behind a turbid medium based on the intensity transmission matrix

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Photonics Research 2022年第10期10卷 2293-2301页

作者： KAIGE liu HENGKANG ZHANG SHANSHAN DU zeqi liu BIN ZHANG XING FU QIANG liu Key Laboratory of Photonics Control Technology Ministry of EducationTsinghua UniversityBeijing 100084China Department of Precision Instrument State Key Laboratory of Precision Measurement Technology and InstrumentsTsinghua UniversityBeijing 100084China Beijing Institute of Control Engineering Beijing 100190China Beijing Institute of Electronic System Engineering Beijing 100854China

Although optical tweezers can manipulate tiny particles,the distortion caused by the scattering medium restricts their application.Wavefront-shaping techniques such as the transmission matrix(TM)method are powerful tools to achieve light focusing behind the scattering medium.In this paper,we propose a method to focus light through a scattering medium in a large area based on the intensity transmission matrix(ITM).Only relying on the intensity distribution,we can calculate the ITM with the number of measurements equal to that of the control segments.Free of the diffraction limit,our method guarantees high energy usage of the light field.Based on this method,we have implemented particle manipulation with a high degree of freedom on single and multiple particles.In addition,the manipulation range is enlarged more than 20 times(compared to the memory effect)to 200μm.

关键词： scattering matrix intensity

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DOA estimation of high-dimensional signals based on Krylov subspace and weighted l_1-norm

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Journal of Systems Engineering and Electronics 2024年第3期35卷 532-540,F0002页

作者： YANG zeqi liu Yiheng ZHANG Hua MA Shuai CHANG Kai liu Ning LYU Xiaode Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China National Key Laboratory of Microwave Imaging Technology Beijing 100190China School of Electronic Electrical and Communication Engineering University of Chinese Academy of SciencesBeijing 100049China Northern Institute of Electronic Equipment Beijing 100191China

With the extensive application of large-scale array antennas,the increasing number of array elements leads to the increasing dimension of received signals,making it difficult to meet the real-time requirement of direction of arrival(DOA)estimation due to the computational complexity of algorithms.Traditional subspace algorithms require estimation of the covariance matrix,which has high computational complexity and is prone to producing spurious peaks.In order to reduce the computational complexity of DOA estimation algorithms and improve their estimation accuracy under large array elements,this paper proposes a DOA estimation method based on Krylov subspace and weighted l_1-norm.The method uses the multistage Wiener filter(MSWF)iteration to solve the basis of the Krylov subspace as an estimate of the signal subspace,further uses the measurement matrix to reduce the dimensionality of the signal subspace observation,constructs a weighted matrix,and combines the sparse reconstruction to establish a convex optimization function based on the residual sum of squares and weighted l_1-norm to solve the target DOA.Simulation results show that the proposed method has high resolution under large array conditions,effectively suppresses spurious peaks,reduces computational complexity,and has good robustness for low signal to noise ratio(SNR)environment.

关键词： direction of arrival(DOA) compressed sensing(CS) Krylov subspace l_1-norm dimensionality reduction

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Mitigating growth-stress tradeoffs via elevated TOR signaling in rice

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Molecular Plant 2024年第2期17卷 240-257页

作者： Wei Li Jiaqi liu zeqi Li Ruiqiang Ye Wenzhen Chen Yuqing Huang Yue Yuan Yi Zhang Huayi Hu Peng Zheng Zhongming Fang Zeng Tao Shiyong Song Ronghui Pan Jian Zhang Jumim Tu Jen Sheen Hao Du State Key Laboratory of Rice Biology College of Agriculture and BiotechnologyZhejiang UniversityYu-Hang-Tang Road No.866Hangzhou 310058China ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang UniversityHangzhou 311215China Hainan Institute of Zhejiang University Sanya 572025China National Key Laboratory of Plant Molecular Genetics CASCenter for Excellence in Molecular Plant SciencesShanghai lnstitute of Plant Physiology and EcologyChineseAcademy of SciencesShanghai 200032China Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region(Ministry of Education) College of Agricultural SciencesGuizhouUniversityGuiyang 550025China State Key Laboratory of Rice Biology and Breeding China National Rice Research InstituteHangzhou 311400China Department of Molecular Biology and Center for Computational and Integrative Biology Massachusetts General Hospitaland Department of GeneticsHarvard Medical SchoolBostonMA02114USA

Rice production accounts for approximately half of the freshwater resources utilized in agriculture,result-ing in greenhouse gas emissions such as methane(CH4)from flooded paddy fields.To address this chal-lenge,environmentally friendly and cost-effective water-saving techniques have become widely adopted in rice cultivation.However,the implementation of water-saving treatments(WsTs)in paddy-field rice has been associated with a substantial yield loss of up to 50%as well as a reduction in nitrogen use efficiency(NUE).In this study,we discovered that the target of rapamycin(TOR)signaling pathway is compromised in rice under WsT.Polysome profiling-coupled transcriptome sequencing(polysome-seq)analysis unveiled a substantial reduction in global translation in response to WST associated with the downregulation of TOR activity.Molecular,biochemical,and genetic analyses revealed new insights into the impact of the positive TOR-S6K-RPS6 and negative TOR-MAF1 modules on translation repression under WST.Intriguingly,ammonium exhibited a greater ability to alleviate growth constraints under WsT by enhancing TOR signaling,which simultaneously promoted uptake and utilization of ammonium and nitrogen allocation.We further demonstrated that TOR modulates the ammonium transporter AMT1;1 as well as the amino acid permease APP1 and dipeptide transporter NPF7.3 at the translational level through the 5'untranslated region.Collectively,these findings reveal that enhancing TOR signaling could mitigate rice yield penalty due to WST by regulating the processes involved in protein synthesis and NUE.Our study will contribute to the breeding of new rice varieties with increased water and fertilizer utilization efficiency.

关键词： target of rapamycin TOR water-saving rice low-carbon agriculture drought nitrogen use efficiency NUE

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农村集体产权制度改革如何影响农民幸福感?——基于中国乡村振兴调查数据的实证分析

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华中农业大学学报（社会科学版） 2024年第1期 86-99页

作者：刘泽琦陈海江陈亚东清华大学中国农村研究院北京100084 绍兴文理学院商学院浙江绍兴312000

运用中国乡村振兴调查(CRRS)数据库2019年数据,实证检验了农村集体产权制度改革对农村居民幸福感的影响及作用机制,并利用Oaxaca-Blinder分解法探究了未完成改革和完成改革两类村民之间幸福感差异的影响因素及各因素的影响程度。结果显... 详细信息

运用中国乡村振兴调查(CRRS)数据库2019年数据,实证检验了农村集体产权制度改革对农村居民幸福感的影响及作用机制,并利用Oaxaca-Blinder分解法探究了未完成改革和完成改革两类村民之间幸福感差异的影响因素及各因素的影响程度。结果显示农村集体产权制度改革显著提高了农村居民幸福感。机制分析表明,农村集体产权制度改革通过壮大村庄集体经济发展水平、减少家庭成员外出就业来增进农村居民幸福感。进一步的异质性分析显示,改革对中低收入和曾经建档立卡贫困户幸福感的促进作用更明显。而结合Oaxaca-Blinder分解结果与农村集体产权制度改革过程中的政策可干预性,增强农民对村干部的信任程度与提升农村治安类公共品供给,是降低改革与未改革两类村民幸福感差异的重要原因。

关键词：农村集体产权制度改革农村居民幸福感 Oaxaca-Blinder分解

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负反馈和状态空间重构的UPWM失真问题校正方法

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声学技术 2024年第1期43卷 127-134页

作者：于泽琦刘豪凯张珂苏安婕郑州轻工业大学计算机与通信工程学院河南郑州450001 中原工学院现代教育技术中心河南郑州450007

针对数字D类音频功率放大器中的均匀采样脉冲宽度调制(Uniform-Sampling Pulse Width Modulation,UPWM)失真,提出了一种负反馈和状态空间重构的全数字UPWM失真问题校正方法。该方法利用数字Σ-Δ(Sigma-Delta)调制器的高开环增益特性,... 详细信息

针对数字D类音频功率放大器中的均匀采样脉冲宽度调制(Uniform-Sampling Pulse Width Modulation,UPWM)失真,提出了一种负反馈和状态空间重构的全数字UPWM失真问题校正方法。该方法利用数字Σ-Δ(Sigma-Delta)调制器的高开环增益特性,通过构造包含数字Σ-Δ调制器和UPWM发生器的闭环负反馈环路,使得环路的输入与输出近似呈线性关系,从而校正UPWM产生的失真。在构造闭环时,通过对数字Σ-Δ调制器的状态空间表达式进行重构,并添加插零值模块和抽取模块使该环路在保持稳定性的同时,拥有与原数字Σ-Δ调制器相同的噪声整形效果。实验结果表明,该方法相比其他的UPWM失真校正方法,不仅能降低谐波失真,还能大幅降低数字UPWM调制器输出信号的本底噪声,从而可使数字UPWM调制器在频率6 kHz和幅度为满量程的-5 dB的正弦数字信号输入情况下,输出信噪失真比达到95.26 dB,同时所提方法可全数字电路实现、硬件实现简单且易于移植。

关键词：均匀采样脉冲宽度调制失真校正状态空间重构负反馈

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硅酸盐抗静电涂层的制备及性能

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电镀与涂饰 2024年第5期43卷 79-85页

作者：曹泽琦姜洪义刘凯高帅武汉理工大学材料科学与工程学院湖北武汉430070

[目的]无机抗静电涂层具有绿色环保、性价比高、耐候性强等优点。[方法]以模数为5.5的硅酸钾溶液作为基料,石墨和氧化铝作为填料,氟碳乳液作为增韧剂,制备了一种新型抗静电涂层。研究了涂料固含量及石墨与氧化铝质量比对涂层硬度、耐磨... 详细信息

[目的]无机抗静电涂层具有绿色环保、性价比高、耐候性强等优点。[方法]以模数为5.5的硅酸钾溶液作为基料,石墨和氧化铝作为填料,氟碳乳液作为增韧剂,制备了一种新型抗静电涂层。研究了涂料固含量及石墨与氧化铝质量比对涂层硬度、耐磨性、拉伸粘结强度和微观结构的影响,并分析了表面电阻随涂层厚度的变化。[结果]在涂料固含量为32%、石墨与氧化铝的质量比为10.0∶9.5、涂层厚度为95μm的情况下所制得的抗静电涂层表面平整,其表面电阻为10^(4)Ω量级、铅笔硬度为9H、磨耗为0.0227 g、拉伸粘结强度为2.350 MPa,力学性能达到最优。[结论]对于硅酸盐抗静电涂层而言,石墨适合作为提升涂层导电性能的填料,氧化铝适合作为增强涂层力学性能的填料。

关键词：硅酸盐抗静电涂层石墨氧化铝表面电阻力学性能

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