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鸡蛋花中2个新的苯甲酸苄基酯类酚苷化合物

中国中药杂志 2024年第5期49卷 1255-1259页

作者：陈正吴美珠郑婷陈雅林孙晨楼永浩周学明海南师范大学、热带药用资源化学教育部重点实验室、海南省热带药用植物化学重点实验室海南海口571158

综合运用多种柱色谱技术采用活性追踪法对鸡蛋花中具有降血糖活性的成分进行了分离纯化,对所有纯化的单体化合物的理化性质进行表征及分析鉴定,共分离鉴定了6个化合物,分别为6-羟基-6″-乙酰基苯甲酸苄基酯-2-O-β-D-葡萄糖苷(1)、6-羟... 详细信息

综合运用多种柱色谱技术采用活性追踪法对鸡蛋花中具有降血糖活性的成分进行了分离纯化,对所有纯化的单体化合物的理化性质进行表征及分析鉴定,共分离鉴定了6个化合物,分别为6-羟基-6″-乙酰基苯甲酸苄基酯-2-O-β-D-葡萄糖苷(1)、6-羟基-6‴-乙酰基苯甲酸苄基酯-2-O-β-D-葡萄糖苷-(1‴→6″)-β-D-葡萄糖苷(2)、2-羟基-6-甲氧基苯甲酸苄基酯-2-O-β-D-葡萄糖苷(3)、6-羟基苯甲酸苄基酯-2-O-β-D-葡萄糖苷(4)、6-羟基苯甲酸苄基酯-2-O-β-D-葡萄糖苷-(1‴→6″)-β-D-葡萄糖苷(5)、6-羟基苯甲酸苄基酯-2-O-β-D-葡萄糖苷-(1‴→6″)-β-D-木糖苷(6)。其中化合物1和2为新化合物,化合物3~6为首次从鸡蛋花属植物中分离得到。对鉴定的6个化合物进行了α-葡萄糖苷酶抑制活性测试,结果表明化合物1~6显示出一定的抑制活性,其IC50为8.2~33.5μmol·L^(-1)。

关键词：鸡蛋花苯甲酸苄基酯糖苷 α-葡萄糖苷酶抑制活性

基于LSD与深度学习的轻量化导地线缺陷检测算法

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光学与光电技术 2024年第1期22卷 60-66页

作者：王勇强周学明张政雷波王晨晟华中光电技术研究所—武汉光电国家研究中心湖北武汉430223 国网湖北省电力有限公司电力科学研究院湖北武汉430077

针对无人机航拍图像尺寸过大,且背景环境复杂带来的导地线缺陷检测速度和精度下降的问题,提出了一种基于LSD与深度学习的轻量化导地线缺陷检测方法。首先利用LSD算法提取图像的直线特征,并结合RANSAC拟合出一条分割基线;然后根据分割基... 详细信息

针对无人机航拍图像尺寸过大,且背景环境复杂带来的导地线缺陷检测速度和精度下降的问题,提出了一种基于LSD与深度学习的轻量化导地线缺陷检测方法。首先利用LSD算法提取图像的直线特征,并结合RANSAC拟合出一条分割基线;然后根据分割基线对导地线区域进行粗分割,剔除大部分背景干扰,减小送入检测网络的图片尺寸;最后通过对YOLOv5的主干网络进行修改,减少网络的计算量,使其更适合在边缘计算设备上部署。实验结果表明,该方法使待检区域大大减小的同时抑制了背景的干扰,使检测精度由原来的67.9%提高到71.3%,同时检测速度提升了12%。本算法具有精度高、速度快、适合在边缘计算设备上部署等优点。

关键词：导地线缺陷检测航拍图像直线段检测直线拟合深度学习

Machine learning for predicting fatigue properties of additively manufactured materials

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Chinese Journal of Aeronautics 2024年第4期37卷 1-22页

作者： Min YI ming xue Peihong CONG Yang SONG Haiyang ZHANG Lingfeng WANG Liucheng zhou Yinghong LI Wanlin GUO State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Institute for Frontier Science Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Shenyang Engine Research Institute Shenyang 110015China Liaoning Key Laboratory of Impact Dynamics on Aero Engine Shenyang 110015China Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi’an 710038China

Fatigue properties of materials by Additive Manufacturing(AM) depend on many factors such as AM processing parameter, microstructure, residual stress, surface roughness, porosities, post-treatments, etc. Their evaluation inevitably requires these factors combined as many as possible, thus resulting in low efficiency and high cost. In recent years, their assessment by leveraging the power of Machine Learning(ML) has gained increasing attentions. A comprehensive overview on the state-of-the-art progress of applying ML strategies to predict fatigue properties of AM materials, as well as their dependence on AM processing and post-processing parameters such as laser power, scanning speed, layer height, hatch distance, built direction, post-heat temperature,etc., were presented. A few attempts in employing Feedforward Neural Network(FNN), Convolutional Neural Network(CNN), Adaptive Network-Based Fuzzy Inference System(ANFIS), Support Vector Machine(SVM) and Random Forest(RF) to predict fatigue life and RF to predict fatigue crack growth rate are summarized. The ML models for predicting AM materials' fatigue properties are found intrinsically similar to the commonly used ones, but are modified to involve AM features. Finally, an outlook for challenges(i.e., small dataset, multifarious features,overfitting, low interpretability, and unable extension from AM material data to structure life) and potential solutions for the ML prediction of AM materials' fatigue properties is provided.

关键词： Additive manufacturing Machine learning Fatigue life Fatigue crack growth rate Prediction

Optimal Timing of Business Conversion for Solvency Improvement

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 744-757页

作者： Peng LI ming zhou School of Finance Nanjing University of Finance and EconomicsNanjing 210023China Center for Applied Statistics and School of Statistics Renmin University of ChinaBeijing 100872China

In this paper,we study the optimal timing to convert the risk of business for an insurance company in order to improve its *** cash flow of company evolves according to a jump-diffusion *** conversion option offers the company an opportunity to transfer the jump risk business *** exchange for this option,the company needs to pay both fixed and proportional transaction *** proportional cost can also be seen as the profit loading of the jump risk *** formulated this problem as an optimal stopping *** solving this stopping problem,we find that the optimal timing of business conversion mainly depends on the profit loading of the jump risk business.A larger profit loading would make the conversion option *** fixed cost,however,only delays the optimal timing of business *** the end,numerical results are provided to illustrate the impacts of transaction costs and environmental parameters to the optimal strategies.

关键词： optimal stopping jump-diffusion process conversion option

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Investigation on UV-curing Reprocessable Thermosets Bearing Hindered Urea Bonds and Their Composites with Modified Zinc Oxide Nanoparticles

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Chinese Journal of Polymer Science 2024年第6期42卷 751-765页

作者： Jun-Hao zhou Li-ming Tang Key Laboratory of Advanced Materials of Ministry of Education of China Department of Chemical EngineeringTsinghua UniversityBeijing100084China

In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot *** prepolymers were characterized fully by various ***,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and *** from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical ***,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their *** influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then *** composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT *** addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.

关键词： Polyurethane-urea methacrylate Hindered urea bond ZnO nanoparticles Reprocessing UV curing

Structural Engineering of Hierarchical Magnetic/Carbon Nanocomposites via In Situ Growth for High-Efficient Electromagnetic Wave Absorption

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Nano-Micro Letters 2024年第9期16卷 262-278页

作者： Xianyuan Liu Jinman zhou Ying xue Xianyong Lu Key Laboratory of Bio‑Inspired Smart Interfacial Science and Technology of Ministry of Education School of ChemistryBeihang UniversityBeijing 100191People’s Republic of China

Materials exhibiting high-performance electromagnetic wave absorption have garnered considerable scientific and technological attention,yet encounter significant *** new materials and innovative structural design concepts is crucial for expanding the application field of electromagnetic wave ***,hierarchical structure engineering has emerged as a promising approach to enhance the physical and chemical properties of materials,providing immense potential for creating versatile electromagnetic wave absorption ***,an exceptional multi-dimensional hierarchical structure was meticulously devised,unleashing the full microwave attenuation capabilities through in situ growth,selfreduction,and multi-heterogeneous interface *** hierarchical structure features a three-dimensional carbon framework,where magnetic nanoparticles grow in situ on the carbon skeleton,creating a necklace-like ***,magnetic nanosheets assemble within this *** impedance matching was achieved by precisely adjusting component proportions,and intelligent integration of diverse interfaces bolstered dielectric *** obtain Fe_(3)O_(4)-Fe nanoparticles/carbon nanofibers/Al-Fe_(3)O_(4)-Fe nanosheets composites demonstrated outstanding performance with a minimum reflection loss(RLmin)value of−59.3 dB and an effective absorption bandwidth(RL≤−10 dB)extending up to 5.6 GHz at 2.2 *** notable accomplishments offer fresh insights into the precision design of high-efficient electromagnetic wave absorption materials.

关键词： Electromagnetic wave absorption Hierarchical structure In situ growth Self-reduction

Surface reconstruction of heterostructures in alkaline medium towards enhanced electrocatalytic hydrogen evolution

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Rare Metals 2024年第6期43卷 2636-2647页

作者： ming-Yang Yang Ji Yuan xue-Lian Fu Jing-Jing Chen Jing Hu zhou-Guang Lu Chen Liu Guangdong Research Center for Interfacial Engineering of Functional Materials Shenzhen Key Laboratory of Polymer Science and TechnologyShenzhen Key Laboratory of Energy Electrocatalytic MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials Department of Materials Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water ***,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains ***,we take the well-designed Ni_(3)S_(2)@VO_(2) heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline *** Ni_(3)S_(2)@VO_(2) heterostructures,with Ni_(3)S_(2) nanorods as the core and VO_(2) nanoflakes as the shell,coupled with the high conductive Ni_(3)S_(2),the hydrophilic VO_(2) and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current ***,the ex-situ characterizations confirmed that the surface reconstruction from Ni_(3)S_(2)@VO_(2) into Ni_(3)S_(2)@amorphous-Ni(OH)_(2) in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic *** study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.

关键词： Heterostructures Ni_(3)S_(2)@VO_(2) Surface reconstruction Water dissociation Alkaline hydrogen evolution

Multi-region calcium imaging in freely behaving mice with ultra-compact head-mounted fluorescence microscopes

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National Science Review 2024年第1期11卷 161-173页

作者： Feng xue Fei Li Ke-ming Zhang Lufeng Ding Yang Wang Xingtao Zhao Fang Xu Danke Zhang mingzhai Sun Pak-ming Lau Qingyuan Zhu Pengcheng zhou Guo-Qiang Bi Department of Precision Machinery and Precision Instruments University of Science and Technology of China Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China Interdisciplinary Center for Brain Information the Brain Cognition and Brain Disease Institute Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Faculty of Life and Health Sciences Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences School of Life Sciences University of Science and Technology of China Institute of Semiconductors Chinese Academy of Sciences Department of Modern Life Sciences and Biotecnology Xiongan Institute of Innovation Xiongan New Area Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions Suzhou Institute for Advanced Research University of Science and Technology of China Institute of Artiflcial Intelligence Hefei Comprehensive National Science Center

To investigate the circuit-level neural mechanisms of behavior, simultaneous imaging of neuronal activity in multiple cortical and subcortical regions is highly desired. Miniature head-mounted microscopes offer the capability of calcium imaging in freely behaving animals. However, implanting multiple microscopes on a mouse brain remains challenging due to space constraints and the cumbersome weight of the ***, we present TINIscope, a Tightly Integrated Neuronal Imaging microscope optimized for electronic and opto-mechanical design. With its compact and lightweight design of 0.43 g, TINIscope enables unprecedented simultaneous imaging of behavior-relevant activity in up to four brain regions in ***-of-concept experiments with TINIscope recorded over 1000 neurons in four hippocampal subregions and revealed concurrent activity patterns spanning across these regions. Moreover, we explored potential multi-modal experimental designs by integrating additional modules for optogenetics, electrical stimulation or local field potential recordings. Overall, TINIscope represents a timely and indispensable tool for studying the brain-wide interregional coordination that underlies unrestrained behaviors.

关键词： miniature microscope multiple sites calcium imaging multimodal integration hippocampus

Can Industrial Structure Upgrading Restrain Industrial Land Expansion?Evidence from China

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Chinese Geographical Science 2024年第3期34卷 504-518页

作者： CHEN Wei LI Qiao ZHANG Sun zhou xue College of Economics and Management Northwest A&F UniversityYangling Shaanxi 712100China Institute of Geographic Sciences&Natural Resources Research Chinese Academy of SciencesBeijing 100101China

China has made great achievements in industrial development and is transforming into a powerful manufacturing ***,the industrial land scale is also ***,whether industrial structure upgrading achieves the purpose of restraining industrial land expansion remains *** calculating the industrial land structure index(ILSI)and industrial land expansion scale(ILES),this study analyzed their temporal and spatial distribution characteristics at both regional and city levels from 2007to 2020 in *** show that industrial land expansion presents a different trend in the four regions,the ILES in the eastern region is the largest,and the speed of industrial land expansion has declined since 2013,but it has gradually increased since *** ILSI of the eastern and central regions is higher than that of the western and northeastern ***,a spatial Durbin model(SDM)has been established to estimate the spatial effect of industrial structure upgrading on industrial land expansion from 2007 ***,industrial structure upgrading has not slowed industrial land *** eastern and western regions require a greater amount of industrial land while upgrading the industrial *** improvement of the infrastructure level and international trade level has promoted industrial land expansion.

关键词： industrial development industrial structure upgrading industrial land expansion regional differences China