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The low-latitude sodium layer:comparative data from lidar observations at Hainan,China and São Paulo,Brazil

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Earth and Planetary Physics 2025年第1期9卷 39-53页

作者： Fang Wu Jing Jiao GuoTao yang LiFang Du ZhengKuan Liu HaoRan Zheng JiXin Guo ShaoHua Gong yaJun zhu State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Hainan National Field Science Observation and Research Observatory for Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China China-Brazil Joint Laboratory for Space Weather NSSC/INPESão Josédos Campos 12227-010Brazil School of Physics and Electronics Engineering Hainan Normal UniversityHaikou 571158China

Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude *** sodium detected by lidar can yield clues to dynamic and chemical processes in these spatial layers above the Earth’s *** paper is based on sodium layer data collected at two low-latitude stations,one in the northern hemisphere and one in the *** low-latitude sodium layer exhibits conspicuous seasonal variations in shape,density.and altitude;these variations are similar between Earth’s hemispheres:sodium layer density at both stations reaches its seasonal maximum in autumn and minimum in ***,maximal Na density over Brazil is greater than that over *** variations of Na density above the two low-latitude stations are also similar;at both,maxima are observed before *** variations of the Na layer over Brazil that differ from those observed in the northern hemisphere may be related to the South Atlantic Magnetic Anomaly(SAMA)or fountain *** suggest that low-latitude Na layer data may provide useful additional evidence that could significantly improve the low-latitude part of the WACCM-Na model.

关键词： metallic sodium layer seasonal variation nocturnal variation lidar

Deep learning-based end-to-end depth estimation from a single-frame fringe pattern with the FDSUNet++ network

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Optoelectronics Letters 2025年

作者： zhu Xinjun ZHANG Jialei SONG Limei WANG Hongyi TIAN Ruiqin School of Artificial Intelligence， Tiangong University School of Control Science and Engineering， Tiangong University

Recently the depth estimation methods based on deep learning (DL) retains challenging to estimate high-precision in fringe projection structured light three-dimensional (3D) measurement with limited information from a single-frame fringe pattern. In this letter， we proposed a FDSUNet++ convolutional neural network， which consists of a UNet++ base model， an improved squeeze-and-excitation (ISE) block， a Fourier transform (FT) data preprocessing block， and a discrete wavelet transform (DWT) block. The proposed ISE block can improve the ability of feature extraction and the designed FT data preprocessing block preserves the key features of the fringe pattern by Fourier transform. The introduced DWT block reduces the complexity.and training cost of the model. By integrating these three blocks into the UNet++ network， it can better achieve depth estimation. Experimental results from two structured light datasets demonstrate that the proposed FDSUNet++ outperforms the state-of-art networks such as UNet， SUNet， R2U-Net， PCTNet and MSUNet++， achieving the best performance in both qualitative and quantitative evaluation.

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Dramatical enhancement of circular dichroism in chiral hybrid perovskites via carboxylic hydrogen bond engineering

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Science China Chemistry 2025年

作者： Hang Li Xinling Li Peng Wang Tingting zhu Ruiqing Li Huang ye yaru Geng Hongliang Dai Junhua Luo State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences University of Chinese Academy of Sciences Fujian College University of Chinese Academy of Sciences College of Chemistry Fuzhou University College of Chemistry.and Materials Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of EducationJiangxi Normal University

Chiral hybrid perovskites （CHPs） have been regarded as promising candidates for developing chiroptoelectronics ***,circular dichroism （CD）,as one of the most important characteristics to evaluate the chiroptical activity,remains at a comparatively low level in CHPs compared to other chiral materials,which hinders the successful applications of CHPs in stateof-the-art ***,exploring new methods for enhancing CD in CHPs is urgently needed and remains ***,enhanced CD response has been successfully realized via constructing carboxylic hydrogen bonding in chiralachiral mixed cations perovskites （R/S-PPA）2（ABA）PbBr5（2R/2S）(PPA=1-phenylpropylamine,ABA=4-aminobutyric acid).Compared with the prototype （R/S-PPA）PbBr3（1R/1S）,2R/2S provide intimate connections between organic units and inorganic parts via carboxylic hydrogen bonding N–H···O bridge,contributing new chirality transfer paths.A larger inorganic skeletons’helicity in 2R/2S predicts a high degree of chirality ***,2R/2S exhibit significantly enhanced CD response with an anisotropy factor amplified by.an order of ***,bright blue circularly polarized luminescence applications are achieved in 2R/*** work systematically investigates the correlation between CD and hydrogen bonding interaction in CHPs,meanwhile providing a new avenue to develop the application potential of chiral materials in chiroptoelectronics.

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New insight into the origin and evolution of the flora and fauna of Hainan Island, China

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Science China Earth Sciences 2025年第1期 52-61页

作者： Hua zhu Center for Integrative Conservation Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Yunnan International Joint Laboratory of Southeast Asia Biodiversity Conservation Yunnan Key Laboratory for the Conservation of Tropical Rainforests and Asian Elephants

The origin of the biota of Hainan Island, China, remains a fundamental scientific problem. Comparative studies on the biota, geological tectonics, and paleomagnetism proposed that during the Eocene, Hainan Island connected Vietnam and Guangxi, and then moved to the southeast to reach its present location. This review mainly discusses its biota origin from molecular phylogeny.and palaeobotanical research. The formation and evolution of the biological groups of Hainan Island were identified via research on their genomes, phylogeny, and molecular biogeography. This research showed that the genera and species that appeared and diverged early in their evolution(i.e., before the Miocene) can be explained by the land connection between Hainan Island, Vietnam, and Guangxi during the Eocene-Oligocene. According to Southeast Asian tectonic theory, in the Middle Miocene(at about 15 million years ago), Hainan Island had moved to its present position. The population and genetic divergence of species with late divergence times(after 15 Ma) can be reasonably explained by the close proximity(or land connection) between Hainan Island and the Leizhou Peninsula, enabling genetic communication between Hainan Island and the Chinese mainland, but have exceptional cases. Conclusions have been obtained through palaeobotanical studies, showing that in the Eocene-Oligocene period, southwest China and Hainan Island had subtropical vegetation and flora. However, the fossil group in southeast China(in Maoming, near present-day Hainan Island) in the Late Eocene indicated a tropical rainforest vegetation and flora. This suggests that in the Paleogene, Hainan Island may have been located near or on the southwest border of Guangxi and northern Vietnam, rather than in its present location. The floristic division of the flora of Hainan Island basically presents a northeast-southwest inclined distribution pattern. This pattern can be explained by the counterclockwise rotation of Hainan Island during i

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Microstructural Dependence of Damping Behaviour of Eutectoid Zn-Al Based Alloy (ZA27)──Discussion of "Damping Behaviour and Mechanism of Graphite Particulate Reinforced Metal Matrix Composites

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Journal of Materials Science & Technology 1999年第2期15卷 178-180页

作者： zhu, y.H. Institute de Investigaciones en Materiales UNAM Mexico D.F. 04510 Apart.P.70-360 Mexico Dept. of Manufacturing Engineering Hong Kong Polytechnic University Hong Kong

A HOMOTOPy METHOD OF SWITCHING SOLUTION BRANCHES AT THE PITCHFORK BIFURCATION POINT

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Journal of Computational Mathematics 2001年第3期19卷 299-308页

作者： Cong, y.-H. zhu, Z.-y. College of Mathematical Sciences Shanghai Teachers University Shanghai 200234 China

Provides information on a study which proposed a continuation method for switching solution branches at a pitchfork point. Problem of the standard pitchfork; Information on the systems of equations; Numerical examples... 详细信息

关键词： homotopy method switching solution branches pitchfork point

Trinuclear gold-catalyzed site-selective alkylation of peptides

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Science China Chemistry 2025年第1期 249-256页

作者： Qing-yun Fang Chengyihan Gu yinghan Chen Wencheng yan yong Liang Weipeng Li Chengjian zhu Jie Han Jin Xie State Key Laboratory of Coordination Chemistry Jiangsu Key Laboratory of Advanced Organic Materials Chemistry and Biomedicine Innovation Center (Chem BIC) School of Chemistry and Chemical Engineering Nanjing University Green Catalysis Center College of Chemistry Zhengzhou University State Key Laboratory of Natural Medicines China Pharmaceutical University

Selective modification of peptides has always been a challenging issue. The selective alkylation of peptides can alter the biological activity.and physical properties of molecules, and it has gained significant research interest. We herein disclose an intriguing gold-catalyzed alkylation of peptides using bench-stable unactivated alkyl bromides under photoredox catalysis. A wide range of structurally diverse primary, secondary.and tertiary alkyl bromides serve as effective coupling partners to precisely connect with the α-C(sp3)–H in glycine residue of peptides. This protocol demonstrates an exceptionally broad scope for alkyl halides and excellent tolerance for a wide range of useful functional groups. A series of relay transformations to construct cyclic peptides, to proceed click reaction and to realize peptide fluorescence labeling further enhance its synthetic practicality. In addition, mechanistic studies and density functional theory(DFT) calculations reveal an inner-sphere and subsequent outersphere single electron transfer(SET) mechanism.

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Review of precipitation strengthening in ultrahigh-strength martensitic steel

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International Journal of Minerals,Metallurgy.and Materials 2025年第2期32卷 256-269页

作者： Zhihao Tian Chunlei Shang Chaolei Zhang Xiaoye Zhou Honghui Wu Shuize Wang Guilin Wu Junheng Gao Jiaming zhu Xinping Mao Institute for Carbon Neutrality University of Science and Technology BeijingBeijing 100083China Institute of Steel Sustainable Technology Liaoning Academy of MaterialsShenyang 110004China Department of Materials Science and Engineering Shenzhen MSU-BIT UniversityShenzhen 518172China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China School of Civil Engineering Shandong UniversityJinan 250061China

Martensite is an important microstructure in ultrahigh-strength steels,and enhancing the strength of martensitic steels often involves the introduction of precipitated phases within the martensitic *** considerable research efforts devoted to this area,a systematic summary of these advancements is *** review focuses on the precipitates prevalent in ultrahigh-strength martensitic steel,primarily carbides(e.g.,MC,M_(2)C,and M_(3)C)and intermetallic compounds(e.g.,Ni Al,Ni_(3)X,and Fe_(2)Mo).The precipitation-strengthening effect of these precipitates on ultrahigh-strength martensitic steel is discussed from the aspects of heat treatment processes,microstructure of precipitate-strengthened martensite matrix,and mechanical ***,a perspective on the development of precipitation-strengthened martensitic steel is presented to contribute to the advancement of ultrahigh-strength martensitic *** review highlights significant findings,ongoing challenges,and opportunities in the development of ultrahigh-strength martensitic steel.

关键词： ultrahigh-strength martensitic steel precipitation strengthening mechanical property carbide intermetallic compound

AN ANALySIS FOR IMPERFECT SENSITIVITy OF A SUPERCONDUCTING ROD

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Acta Mechanica Solida Sinica 1996年第3期9卷 236-245页

作者： Xiao, y zhu, yy LANZHOU UNIV DEPT MECHLANZHOU 730000PEOPLES R CHINA

On the basis of the interaction between the electromagnetic field and a solid, the imperfect sensitivity of a superconducting rod is studied in this paper. The influences of the initial deflection of the rod and the initial magnetic field on the stability are discussed. One can see that the bifurcation response of the rod with imperfections is similar to the universal unfolding of the fork bifurcation from the singularity theory.

关键词： magneto-elasticity superconducting rod imperfect sensitivity bifurcation figure