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Gradient maturation experiment on hairs implies taphonomic changes in fossil hairs

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Science China Earth Sciences 2025年第1期68卷 62-73页

作者： Xin LI Yibo ZHOU tao ZHAO xingjian HE Yanhong PAN State Key Laboratory for Mineral Deposits Research Center for Critical Earth Material Cycling Centre for Research and Education on Biological Evolution and Environment and Frontiers Science School of Earth Sciences and Engineering Nanjing University Institute of Palaeontology Yunnan Key Laboratory of Earth System Science Yunnan Key Laboratory for PalaeobiologyYunnan University

Mammalian hair, as a key feature related to endothermy, physical protection, and camouflage, has a long geohistorical record that dates back even to the Mesozoic. However, the limited information on the taphonomy of hair hinders the understanding of its evolutionary significance in deep time. To address this, we conducted taphonomic experiments to simulate the transformation process of black hair. The changes in the morphological structure, microscopic characteristics, and chemical composition of hair during the simulated fossilization process were documented by scanning electron microscopy, Fourier transform infrared(FTIR) spectroscopy, and Raman spectroscopy. Our results revealed that damage to the morphology of hair began at a mild temperature(150–175°C), and hair transformed into a fluid-like mass at a relatively high temperature(200°C). In addition, the morphological structure of melanosomes had relatively greater preservation potential than keratins did, and the microscopic features of melanosomes were persistently stable. The Raman and FTIR spectra indicated that the characteristic melanin and keratin peaks changed as the temperature increased. Although the chemical signals were not lost completely, the variations in the characteristic amide bands in the FTIR spectra indicate that the keratins severely degraded at high temperatures(>200°C), whereas the characteristic melanin bands in the Raman spectra suggested that melanin signals were still recognizable, even at high temperatures(>200°C). These results were confirmed by principal component analysis(PCA) and principal component analysis linear discriminant analysis(PCA–LDA). In addition, the Raman signals of all the samples in the simulated experiments were distinguished from the signals of common geological carbonaceous materials(humic acid), which suggested that Raman spectroscopy can be used to detect melanin in fossils.

关键词： Mammalian hair Melanin Keratin Fossilization Experimental taphonomy

贵州省城市饮用水水源地保护现状评价及措施规划研究

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人民珠江 2017年第1期38卷 83-86页

作者：严涛王兴建贵州省水利水电勘测设计研究院贵州贵阳550002

随着贵州省城镇化进程的加快,城市饮用水水源地受污染的风险加大,为摸清水源地现状安全状况并提出合适的保护措施,在贵州省城市饮用水水源地全面调查的基础上,从饮用水水源地水质方面评价饮用水水源地安全状况,针对存在的问题,采取隔离... 详细信息

随着贵州省城镇化进程的加快,城市饮用水水源地受污染的风险加大,为摸清水源地现状安全状况并提出合适的保护措施,在贵州省城市饮用水水源地全面调查的基础上,从饮用水水源地水质方面评价饮用水水源地安全状况,针对存在的问题,采取隔离防护与宣传警示工程、污染综合整治工程、生态保护与修复工程三大类工程措施来开展水源地保护规划。全省133个饮用水水源地,水质综合评价合格率为96.2%。以现状评价不合格水源地和国家重要饮用水水源地为保护重点制定保护措施,规划总投资65.1亿元,为贵州省广大城镇居民构筑坚实的饮水安全防线。

关键词：城市饮用水水源地保护贵州省

Experimental Investigation on Plasma-assisted Combustion Characteristics of Premixed Propane/Air Mixture

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Journal of Thermal Science 2015年第3期24卷 283-289页

作者： LIU xingjian HE Liming YU Jinlu ZENG Hao JIN tao Science and Technology on Plasma Dynamics Laboratory Aeronautics and Astronautics Engineering College Air Force Engineering University

A detailed study on the plasma-assisted combustion(PAC) characteristics of premixed propane/air mixture is presented. The PAC is measured electrically, as well as optically with a multichannel spectrometer. The characteristics are demonstrated by stable combustion temperature and combustion stability limits, and the results are compared with conventional combustion(CC). Stable combustion temperature measurements show that the introduction of PAC into combustion system can increase the stable combustion temperature, and the increment is more notable with an increase of discharge voltage. Besides, the rich and weak limits of combustion stability are both enlarged when plasma is applied into the combustion process and the increase of discharge voltage results in the expansion of combustion stability limits as well. The measurements of temperature head and emission spectrum illustrate that the kinetic enhancement caused by reactive species in plasma is the main enhancement pathway for current combustion system.

关键词： Plasma-assisted combustion Stable combustion temperature Combustion stability limits Mechanism

Neural network assisted high-spatial-resolution polarimetry with non-interleaved chiral metasurfaces

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Light(Science & Applications) 2023年第12期12卷 2732-2741页

作者： Chen Chen xingjian Xiao Xin Ye Jiacheng Sun Jitao Ji Rongtao Yu Wange Song Shining Zhu tao Li Nanjing University National Laboratory of Solid State MicrostructuresKey Laboratory of Intelligent Optical Sensing and ManipulationsJiangsu Key Laboratory of Artificial Functional MaterialsCollege of Engineering and Applied Sciences210093 NanjingChina

Polarimetry plays an indispensable role in modern ***,the current strategies generally suffer from bulky system volume or spatial multiplexing scheme,resulting in limited performances when dealing with inhomogeneous ***,we propose a non-interleaved,interferometric method to analyze the polarizations based on a tri-channel chiral metasurface.A deep convolutional neural network is also incorporated to enable fast,robust and accurate *** uniform and nonuniform polarizations are both measured through the metasurface *** between two semblable glasses is also *** strategy features the merits of compactness and high spatial resolution,and would inspire more intriguing design for detecting and sensing.

关键词： chiral resolution polar

Large-scale achromatic flat lens by light frequency-domain coherence optimization

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Light(Science & Applications) 2022年第12期11卷 2900-2908页

作者： xingjian Xiao Yunwei Zhao Xin Ye Chen Chen Xinmou Lu Yansen Rong Junhong Deng Guixin Li Shining Zhu tao Li National Laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and ManipulationsJiangsu Key Laboratory of Artificial Functional MaterialsCollege of Engineering and Applied SciencesNanjing UniversityNanjing 210093China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China

Flat lenses,including metalens and diffractive lens,have attracted increasing attention due to their ability to miniaturize the imaging ***,realizing a large scale achromatic flat lens with high performance still remains a big ***,we developed a new framework in designing achromatic multi-level diffractive lenses by light coherence optimization,which enables the implementation of large-scale flat lenses under non-ideal *** results,a series achromatic polymer lenses with diameter from 1 to 10mm are successfully designed and *** subsequent optical characterizations substantially validate our theoretical framework and show relatively good performance of the centimeter-scale achromatic multi-level diffractive lenses with a super broad bandwidth in optical wavelengths(400-1100 nm).After comparing with conventional refractive lens,this achromatic lens shows significant advantages in white-light imaging performance,implying a new strategy in developing practical planar optical devices.

关键词： conditions chromatic optimization

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掌上多功能超声波测厚仪的研制

武汉化工学院学报 2001年第4期23卷 72-74页

作者：杨陶李行健陈绪耀武汉化工学院自动化系湖北武汉430073 武汉大学电子信息学院湖北武汉430073 武钢冷轧厂湖北武汉430008

以实际的研制经验 ,叙述了掌上多功能超声波测厚仪采用的原理。

关键词：超声检测单片机掌上多功能超声波测厚仪

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宽带消色差平面透镜的设计与参量分析

红外与激光工程 2020年第9期49卷 53-60页

作者：肖行健祝世宁李涛南京大学现代工程与应用科学学院江苏南京210023

大尺寸、大数值孔径、宽波段的消色差平面透镜设计是成像技术的一个瓶颈性问题,也是近年来超构透镜研究领域的一个重要挑战,主要原因是透镜的各个参量之间存在内禀的制约关系。文中结合消色差透镜的群时延理论及透镜的相位分布,通过理... 详细信息

大尺寸、大数值孔径、宽波段的消色差平面透镜设计是成像技术的一个瓶颈性问题,也是近年来超构透镜研究领域的一个重要挑战,主要原因是透镜的各个参量之间存在内禀的制约关系。文中结合消色差透镜的群时延理论及透镜的相位分布,通过理论分析给出各参量之间的半定量制约关系。同时,分别通过拓扑优化和直接二值搜索的方法,设计了不同参量下的消色差超构透镜和多阶衍射透镜,发现在保持效率80%左右的前提下,透镜尺寸增加了一倍,数值孔径或波段宽度减少了一半,而透镜厚度则随尺寸成线性增长。该结果表明,这两类平面透镜具有相同的內禀参数依赖关系,即透镜尺寸与数值孔径和波段宽度呈现反相关、与透镜厚度呈现正相关的关系,这与理论预测基本一致。

关键词：平面透镜消色差参量优化

Bandpass-filter-integrated multiwavelength achromatic metalens

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Photonics Research 2021年第7期9卷 1384-1390页

作者： HANMENG LI xingjian XIAO BIN FANG SHENGLUN GAO ZHIZHANG WANG CHEN CHEN YUNWEI ZHAO SHINING ZHU tao LI National Laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and ManipulationJiangsu Key Laboratory of Artificial Functional MaterialsCollege of Engineering and Applied SciencesNanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

The design of large-scale,high-numerical-aperture,and broadband achromatism is a big challenge in metalens research. In fact,many colorful imaging systems have RGB color filters,which means the achromatism only for RGB lights would be sufficient. Avoiding broadband achromatism is expected to greatly improve the working efficiency of metalenses. Nevertheless,a proper bandpass filter is necessary under a white light illumination in the metalens integrated imaging system. Here we propose a bandpass-filter-integrated multiwavelength achromatic metalens (NA=0.2),which is designed using a searching optimization algorithm to achieve the achromatism of RGB lights with high efficiencies. The bandpass filter is implemented by composite DBRs and defect layers,by which three desired wavelengths are selected out. The simulations and experiments on the filter-integrated metalens definitely show a good RGB achromatism. Further imaging experiments demonstrate a higher signal-to-noise ratio and resolution compared with the one without the filter. Our approach provides not only an RGB achromatic meta-imaging device but also a new route to access a highly efficient spectrum tailoring metasystem by incorporating bandpass filter designs.

关键词： filter lights illumination

Chip-scale metalens microscope for wide-field and depth-of-field imaging

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Advanced Photonics 2022年第4期4卷 68-75页

作者： Xin Ye Xiao Qian Yuxin Chen Rui Yuan xingjian Xiao Chen Chen Wei Hu Chunyu Huang Shining Zhu tao Li Nanjing University College of Engineering and Applied SciencesNational Laboratory of Solid State MicrostructuresKey Laboratory of Intelligent Optical Sensing and IntegrationJiangsu Key Laboratory of Artificial Functional MaterialsNanjingChina Collaborative Innovation Center of Advanced Microstructures NanjingChina

Microscopy is very important in research and industry,yet traditional optical microscopy suffers from the limited field-of-view(FOV)and depth-of-field(DOF)in high-resolution *** demonstrate a simultaneous large FOV and DOF microscope imaging technology based on a chip-scale metalens device that is implemented by a SiNxmetalens array with a co-and cross-polarization multiplexed dual-phase design and dispersive spectrum zoom effect.A 4-mm×4-mm FOV is obtained with a resolution of 1.74μm and DOF of200μm within a wavelength range of 450 to 510 nm,which definitely exceeds the performance of traditional microscopes with the same ***,it is realized in a miniaturized compact prototype,showing an overall advantage for portable and convenient microscope technology.

关键词： metalens microscope wide-field imaging