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Nonlinear optical response of niobium telluride and its application for demonstrating pulsed fiber lasers

Journal of Materiomics 2024年第2期10卷 355-365页

作者： Xinxin Shang Yule Zhang Tuo li Huanian Zhang Xiaofeng Zou S.Wageh Ahmed A.Al-Ghamdi Han Zhang Shuhao Si dengwang li Shandong Province Key Laboratory of Medical Physics and Image Processing Technology Shandong Provincial Key Laboratory of Optics and Photonic DeviceSchool of Physics and ElectronicsShandong Normal UniversityJinan250014China Institute of Microscale Optoelectronics College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China Shandong Yunhai Guochuang Cloud Computing Equipment Industry Innovation Co. Ltd.JinanShandongChina School of Physics and Optoelectronic Engineering Shandong University of TechnologyZibo255049China Department of Physics Faculty of ScienceKing Abdulaziz UniversityJeddah21589Saudi Arabia

Niobium telluride(NbTe_(2)),a kind of few-layer two-dimensional(2D)transition metal dichalcogenides(TMDs)material,has been theoretically predicted with nonlinear absorption properties and excellent optical ***,we experimentally demonstrated an Er-doped fiber(EDF)laser based NbTe_(2)as saturable absorber(SA).Few-layer NbTe_(2)nanosheets were successfully prepared by adopting the commonly used liquid-phase exfoliation(LPE)*** nonlinear optical response of highly stable few-layer NbTe_(2)was investigated through an open-aperture Z-scan laser measurement,the nonlinear absorption coefficient was 2.45×10^(-11)m/*** Q-switched and mode-locked operation centered at 1559 nm were recorded based on NbTe_(2)*** pulse duration was varied from 4.88 ms to 1.75 ms,and the adjustable range of repetition frequency is changed from 44.01 kHz to 64.12 kHz in passively Q-switched ***,a constant repetition rate of 5.33 MHz and pulse width of 2.67 ps were observed in mode-locked *** experimental results fully reveal the nonlinear optical prop-erties of NbTe_(2)used in pulsed fiber lasers and broaden its ultrafast applications in the optics field.

关键词： Niobium telluride Saturable absorber Z-scan Mode-locked pulse Fiber laser

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Automated segmentation of intraretinal cystoid macular edema based on Gaussian mixture model

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Journal of Innovative Optical Health Sciences 2020年第1期3卷 35-47页

作者： Jinghong Wu Sijie Niu Qiang Chen Wen Fan Songtao Yuan dengwang li Shandong Key Laboratory of Medical Physics and Image Processing&Shandong Provincial Engineering and Technical Center of light Manipulations School of Physics and Electronics Shandong Normal University Jinan 250358P.R.China School of Information Science and Engineering University of Jinan Jinan 250022P.R.China School of Computer Science and Engineering Nanjing University of Science and Technology Nanjing 210094 P.R.China Department of Ophthalmology the First Affiliated Hospital with Nanjing Medical University Nanjing 210094P.R.China

We introduce a method based on Gaussian mixture model(GMM)clustering and level-set to automatically detect intraretina fluid on diabetic retinopathy(DR)from spectral domain optical coherence tomography(SD-OCT)images in this ***,each B-scan is segmented using GMM *** original chustering results are refined using location and thickness ***,the spatial information among every consecutive five B-scans is used to search potential ***,the improved level-set method is used to obtain the accurate *** high sensitivity and accuracy demonstrated here show its potential for detection of fluid.

关键词： Gaussian mixture model level-set spectral domain optical coherence tomography(SD-OCT) segmentation

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Niobium telluride absorber for a mode-locked vector soliton fiber laser

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Science China(Physics,Mechanics & Astronomy) 2023年第5期66卷 130-138页

作者： XinXin Shang NanNan Xu Jia Guo Shuo Sun HuaNian Zhang SWageh Ahmed AAl-Ghamdi Han Zhang dengwang li Shandong Province Key Laboratory of Medical Physics and Image Processing Technology Shandong Provincial Key Laboratory of Optics and Photonic DeviceSchool of Physics and ElectronicsShandong Normal UniversityJinan 250014China Institute of Microscale Optoelectronics Collaborative Innovation Center for Optoelectronic Science&TechnologyKey Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen Key Laboratory of Micro-Nano Photonic Information TechnologyGuangdong Laboratory of Artificial Intelligence and Digital Economy(SZ)Shenzhen UniversityShenzhen 518060China School of Physics and Optoelectronic Engineering Shandong University of TechnologyZibo 255049China Department of Physics Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia

Niobium telluride(NbTe_(2)),an emerging transition metal dichalcogenide material,has been theoretically predicted to have nonlinear absorption properties and excellent optical ***,only a few studies of the utilization of NbTe_(2)in ultrafast photonics have been *** this work,a NbTe_(2)-based saturable absorber(SA)was applied in an erbium-doped fiber as a mode-locked device,and a vector soliton based on NbTe_(2)was obtained for the first ***_(2)-PVA film SA was successfully prepared by the liquid-phase exfoliation and spin coating methods,with a modulation depth of up to 10.87%.The nonlinear absorption coefficient of NbTe_(2)-based SA film tested through the open-aperture Z-scan laser measurement is 0.62×10^(−11) m/W.A conventional soliton with a pulse duration of 858 fs was generated using NbTe_(2)-based SA,which was demonstrated to be a kind of polarization-locked vector soliton in further *** experimental results reveal the nonlinear optical properties of NbTe_(2)and broaden its applications in ultrafast photonic devices.

关键词： niobium telluride saturable absorber mode-locked pulse fiber laser

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Two-dimensional particle-in-cell modeling of blow-off impulse by X-ray irradiation

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Nuclear Science and Techniques 2024年第3期35卷 53-69页

作者： Ruibo li Jin-Long Jiao Hui Luo Dezhi Zhang dengwang Wang Kai Wang Graduate School of China Academy of Engineering Physics Beijing 100193China Zhejiang Institute of Modern Physics Institute of AstronomySchool of PhysicsZhejiang UniversityHangzhou 310027China National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an 710024China

Space objects such as spacecraft or missiles may be exposed to intense X-rays in outer space,leading to severe *** reinforcement of these objects to reduce the damage caused by X-ray irradiation is a significant *** blow-off impulse(BOI)is a crucial physical quantity for investigating material damage induced by X-ray ***,the accurate calculation of BOI is challenging,particularly for large deformations of materials with complex *** this study,we develop a novel two-dimensional particle-in-cell code,Xablation2D,to calculate BOIs under far-field X-ray *** significantly reduces the dependence of the numerical simulation on the grid *** reliability of this code is verified by simulation results from open-source codes,and the calculated BOIs are consistent with the experimental and analytical results.

关键词： X-ray irradiation Energy deposition Blow-off impulse Particle in cells

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Passive mode-locked Er-doped fiber laser pulse generation based on titanium disulfide saturable absorber

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Frontiers of Information Technology & Electronic Engineering 2021年第5期22卷 756-766页

作者： Xinxin SHANG linguang GUO Huanian ZHANG dengwang li Qingyang YUE Shandong Provincial Engineering and Technical Center of light Manipulations Shandong Provincial Key Laboratory of Optics and Photonic DeviceSchool of Physics and ElectronicsShandong Normal UniversityJinan 250358China School of Physics and Optoelectronic Engineering Shandong University of TechnologyZibo 255049China Shandong Key Laboratory of Medical Physics and Image Processing School of Physics and ElectronicsShandong Normal UniversityJinan 250358China Shandong Institute of Industrial Technology for Health Sciences and Precision Medicine School of Physics and ElectronicsShandong Normal UniversityJinan 250358China

In this study,titanium disulfide(TiS_(2))polyvinyl alcohol(PVA)film-type saturable absorber(SA)is synthesized with a modulation depth of 5.08%and a saturable intensity of 10.62 MW/cm^(2) by liquid-phase exfoliation and spin-coating *** TiS2-based SA has a strong nonlinear saturable absorption property,two types of optical soliton were observed in a mode-locked Er-doped fiber *** the pump power was raised to 67.3 mW,a conventional mode-locked pulse train with a repetition rate of 1.716 MHz and a pulse width of 6.57 ps was generated,and the output spectrum centered at 1556.98 nm and 0.466 nm spectral width with obvious Kelly sidebands was *** type of mode-locked pulse train with the maximum output power of 3.92 mW and pulse energy of 2.28 nJ at the pump power of 517.2 mW was achieved when the polarization controllers were *** TiS2-based SA has excellent nonlinear saturable absorption characteristics,broad applications in ultrafast photonic are expected.

关键词： Fiber laser Passive mode-locked Saturable absorber Titanium disulfide

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Micro EEG/ECG signal's chopper-stabilization amplifying chip for novel drycontact electrode

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Journal of Semiconductors 2017年第2期38卷 96-104页

作者： Jianhui Sun Chunxing Wang Gongtang Wang Jinhui Wang Qing Hua Chuanfu Cheng Xinxia Cai Tao Yin Yang Yu Haigang Yang dengwang li College of Physics and Electronics Shandong Normal University Jinan 240014 China Institute of Electronics Chinese Academy of Sciences Beijing 100190 China Shandong Province Key Laboratory of Medical Physics and Image Processing Technology Institute of BioelectronicsShandong Normal University Jinan 240014 China Department of Electronical and Computer Engineering North Dakota State University Fargo ND 58102 USA

Facing the body＇s EEG（electroencephalograph, 0.5–100 Hz, 5–100 μV） and ECG＇s（electrocardiogram,〈 100 Hz, 0.01–5 mV） micro signal detection requirement, this paper develops a pervasive application micro signal detection ASIC chip with the chopping modulation/demodulation method. The chopper-stabilization circuit with the RRL（ripple reduction loop） circuit is to suppress the ripple voltage, which locates at the single-stage amplifier＇s outputting terminal. The single-stage chopping core＇s noise has been suppressed too, and it is beneficial for suppressing noises of post-circuit. The chopping core circuit uses the PFB（positive feedback loop） to increase the inputting resistance, and the NFB（negative feedback loop） to stabilize the 40 dB intermediate frequency gain. The cascaded switch-capacitor sample/hold circuit has been used for deleting spike noises caused by non-ideal MOS switches, and the VGA/BPF（voltage gain amplifier/band pass filter） circuit is used to tune the chopper system＇s gain/bandwidth digitally. Assisted with the designed novel dry-electrode, the real test result of the chopping amplifying circuit gives some critical parameters： 8.1 μW/channel, 0.8 μVrms（@band-widthD100 Hz）, 4216–11220 times digitally tuning gain range, etc. The data capture system uses the NI CO＇s data capturing DAQmx interface,and the captured micro EEG/ECG＇s waves are real-time displayed with the PC-Labview. The proposed chopper system is a unified EEG/ECG signal＇s detection instrument and has a critical real application value.

关键词： EEG/ECG novel dry-contact electrode weak and micro signal detection chopping modulation/demodulation de-noising gain/band width digitally tuning

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基于小波变换的多分辨率锥束CT图像快速三维重建算法

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电子与信息学报 2017年第10期39卷 2437-2441页

作者：韩民成旭李登旺山东大学信息科学与工程学院济南250100 山东师范大学物理与电子科学学院济南250014

为了解决FDK重建算法在锥束CT重建中运算量大,耗时较多,以及针对不同的应用环境提供不同分辨率的3维医学图像问题,该文提出一种基于小波变换的多分辨率锥束CT图像快速3维重建算法。首先对采集到的投影图像进行相应尺度的小波变换,得到... 详细信息

为了解决FDK重建算法在锥束CT重建中运算量大,耗时较多,以及针对不同的应用环境提供不同分辨率的3维医学图像问题,该文提出一种基于小波变换的多分辨率锥束CT图像快速3维重建算法。首先对采集到的投影图像进行相应尺度的小波变换,得到各尺度小波分解系数,选择相应尺度的小波系数进行FDK重建,可以得到相应低分辨率的3维图像数据,还可根据需要由得到的低分辨率重建数据分别沿着径向取断层图像,进行相应的小波逆变换,进而得到高分辨率的3维图像数据。实验数据表明,该方法不仅能够得到不同分辨率的3维图像数据,而且相较于传统的FDK算法生成分辨率相同、精度相近的高分辨率3维图像数据,重建速度可以提高1倍以上。

关键词：锥束CT FDK重建小波变换多分辨率

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规模经营背景下农户参与农业技术培训的影响因素研究——基于全国4省数据的实证分析

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中国农业资源与区划 2021年第5期42卷 228-236页

作者：李浩李登旺中国社会科学院研究生院中国社会科学院农村发展研究所

[目的]利用全国4省1 039户农户调查数据,深入分析在规模经营背景下影响农户参与农业技术培训的相关因素,进而为改进农业技术培训政策、促进农业现代化提供有益借鉴。[方法]文章在控制农户户主个人特征、家庭特征、村庄特征及地区特征的... 详细信息

[目的]利用全国4省1 039户农户调查数据,深入分析在规模经营背景下影响农户参与农业技术培训的相关因素,进而为改进农业技术培训政策、促进农业现代化提供有益借鉴。[方法]文章在控制农户户主个人特征、家庭特征、村庄特征及地区特征的基础上,将农户分为规模经营农户和普通小农户两类,构建零膨胀负二项模型解决样本数据存在的"零膨胀"问题和"过离散"问题,分析影响规模经营农户与普通农户参加农业技术培训的相关因素。[结果]是否规模经营、家庭劳动力比例、是否参加农业合作社等家庭特征变量,户主年龄和受教育程度等户主特征,乡镇农技员数量以及地区虚拟变量,是影响农户参加农业技术培训的重要因素。其中,规模经营农户的平均农技培训参加次数显著高于普通农户,为其1.276倍,规模经营户的农技培训参加次数发生率之比要比非规模经营户高27.6%;家庭劳动力比例对参加农业技术培训的次数呈现显著的正向影响,劳动力比例每提高1个百分点,农户参加农技培训的可能性提高61.3%;农户是否加入合作社对参加农业技术培训存在显著的负向影响,合作社成员参加农技培训的发生率之比要比非合作社成员低26.6%;户主年龄对农户参加农业技术培训存在负向影响,户主年龄每增加1岁其参加农业技术培训的可能性就会降低1.1%;户主受教育程度越高,农户平均参加农业技术培训次数的发生率之比显著提升;而乡镇农技员数量对农户参加农业技术培训存在显著的负向影响。就地区而言,相对于黑龙江地区,四川、河南地区农户参加农业技术培训的可能性相对较低。[结论]年龄相对较小、受教育水平相对较高、从事规模经营的农户更倾向于参加农业技术培训,且表现出一定的地区差异。政府开展农业技术培训,应当更多地向青年农民、规模经营农户倾斜,且需要根据各地实际情况因地制宜制定培训政策。

关键词：规模经营农业技术培训影响因素零膨胀负二项模型实证分析

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重要农产品价格形成机制改革背景下粮食型家庭农场发展困境与对策研究

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价格理论与实践 2019年第1期 35-39页

作者：李登旺韩磊中国社会科学院农村发展研究所

粮食型家庭农场不断发展壮大,逐渐成我国粮食供给的重要主体,为保障国家粮食安全发挥了重要作用。当前开展的重要农产品价格形成机制改革,为粮食型家庭农场调整生产结构、优化粮食品种、提升产品竞争力提供了机遇。但粮食价格不断下降... 详细信息

粮食型家庭农场不断发展壮大,逐渐成我国粮食供给的重要主体,为保障国家粮食安全发挥了重要作用。当前开展的重要农产品价格形成机制改革,为粮食型家庭农场调整生产结构、优化粮食品种、提升产品竞争力提供了机遇。但粮食价格不断下降、农业生产成本不断上升,严重压缩了粮食型家庭农场的利润空间,导致一些粮食型家庭农场陷入经营困境。本文在概述新一轮农产品价格形成机制改革及其进展的基础上,详细分析了当前粮食型家庭农场发展面临的困境,并进一步提出了促进粮食型家庭农场摆脱转型发展困境的政策建议。

关键词：农产品价格价格形成机制改革粮食型家庭农场

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基于分组主成分分析的光学相干图像降斑算法

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光学学报 2018年第10期38卷 260-266页

作者：方敬滕树云牛四杰李登旺山东师范大学物理与电子科学学院山东省医学物理图像处理技术重点实验室山东省光学与光子器件重点实验室山东济南250358 济南大学信息与科学工程学院山东济南250022

通过分析临床医学图像中光学相干断层成像(OCT)的相干斑噪声模型,提出了一种基于局部分组主成分分析的光学相干断层图像降斑算法。根据相干图像的统计特征,利用同态滤波将乘性噪声转换为加性噪声;将训练集中待处理的像素及其邻域表示成... 详细信息

通过分析临床医学图像中光学相干断层成像(OCT)的相干斑噪声模型,提出了一种基于局部分组主成分分析的光学相干断层图像降斑算法。根据相干图像的统计特征,利用同态滤波将乘性噪声转换为加性噪声;将训练集中待处理的像素及其邻域表示成子块向量,利用块相似性度量对子块进行分组,并用于主成分分析。为有效抑制相干图像中病灶的噪声干扰,将该算法执行两次。实验结果表明:所提算法在降斑的同时较好地保留了图像的细节信息,而且获得了较高的客观评价指标。

关键词：图像处理光学相干成像斑点噪声主成分分析块相似

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