检索结果-内蒙古大学图书馆

Two-dimensional violet phosphorus as a broadband saturable absorber for mid-infrared photonics

Optics Express 2025年第10期33卷 21328-21338页

作者： Bo Li Han Pan Zhongben Pan Hongwei Chu Ying Li Shengzhi Zhao Dechun Li School of Information Science and Engineering Shandong Provincial Key Laboratory of Laser Technology and Application and Key Laboratory of Laser and Infrared System of Ministry of Education Shandong University Qingdao 266237 China hanpan@*** Key Laboratory of Colloid and Interface Chemistry of Education Ministry and School of Chemistry and Chemical Engineering Shandong University Jinan 250100 China dechun@***

Two-dimensional (2D) violet phosphorus (VP), a recently investigated 2D semiconductor material, is promising for advanced optoelectronic applications because of its distinct physical and chemical features. In this work, high-quality, few-layered, 2D VP nanosheets were prepared, and their nonlinear optical (NLO) absorption characteristics were examined in detail in the 2 and 3 μm bands. The calculated high nonlinear absorption coefficients, low saturation intensities, and high modulation depths of 2D VP nanosheets demonstrated their exceptional mid-infrared (MIR) saturable absorption properties and significant potential for MIR photonic applications. Thus, in the Tm: GdVO 4 laser and Er: YAP laser, we employed 2D VP as a broadband saturable absorber (SA), and obtained stable Q-switched pulse outputs with pulse durations of 522.6 ns at 1.9 μm and 195 ns at 2.8 μm, respectively. In particular, the pulse width obtained at 3 µm based on 2D VP-SA is much narrower compared to that obtained for most other 2D materials SAs. These results demonstrate that 2D VP can be a potential candidate for broadband MIR SA.

关键词： Absorption coefficient Nonlinear absorption Optical properties Saturable absorbers Semiconductor saturable absorber mirrors Solid state lasers

来源：评论

学校读者我要写书评

暂无评论

Influence of Interspecies Interactions on Bacterial Community Assembly in the Active and Permafrost Layers on the Qinghai-Tibet Plateau

引用

Journal of Earth Science 2025年第2期36卷 395-407页

作者： Hongfei Chi Xiufeng Yin Xuefeng Zhang Jingyi Zhu Lin Zhao Yongcui Deng Pengfei Liu Yongqin Liu College of Ecology Lanzhou UniversityLanzhou 730000China Center for the Pan-Third Pole Environment Lanzhou UniversityLanzhou 730000China State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of ScienceLanzhou 730000China State Key Laboratory of Tibetan Plateau Earth System Resources and Environment(TPESRE)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China School of Geographical Sciences Nanjing University of Information Science and TechnologyNanjing 210044China School of Geography Nanjing Normal UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function *** interaction is one of the main factors in shaping soil bacterial ***,how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau(QTP)remains largely *** we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River(TTH)and May 2022 for Aerjin(ARJ),and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA *** study revealed distinct bacterial communities,with significant differences in the relative abundances of Proteobacteria(P<0.05),Acidobacteriota(P<0.001),Bacteroidota(P<0.05),and Planctomycetota(P<0.001)between the active layer and the permafrost *** importantly,we found that interspecies interactions,including both positive and negative associations,were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly *** findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes,with interspecies interactions accounting for more than 58%and 63%of all assembly mechanisms,*** is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP,highlighting the importance of considering interspecies interactions in future modeling *** work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.

关键词： permafrost the Qinghai-Tibet Plateau bacterial community Interspecies interaction community assembly process biogeology

来源：评论

学校读者我要写书评

暂无评论

Predicting on the Extreme Precipitation in East and Southeast Asia during Summer 2022 from the Antecedent Soil Temperature Anomaly over the Tibetan Plateau

引用

Journal of Climate 2025年第9期38卷 2109-2128页

作者： Kong, Xianghui Wang, Aihui Xue, Yongkang Wei, Nan Zhang, He Hu, Qin He, Juanxiong Bi, Xunqiang Chen, Yue Nansen-Zhu International Research Centre Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and Technology Nanjing China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology Sichuan Province Chengdu China University of California Los AngelesCA United States School of Atmospheric Sciences Sun Yat-sen University Zhuhai China International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China School of Atmospheric Sciences Chengdu University of Information Technology Sichuan Province Chengdu China Climate Change Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China National Super Computer Center in Tianjin Tianjin China State Key Laboratory of Earth System Numerical Modeling and Application Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

It has demonstrated that May land surface temperature (LST) and subsurface temperature (SUBT) anomalies on the Tibetan Plateau (TP) can serve as a predictor of June precipitation in downstream *** summer 2022, there was heavy precipitation (severe drought) in June (August) over southern China, coinciding with high May (July) LST/SUBT anomalies in *** the framework of the Impact of Initialized Land Temperature and Snowpack on Subseasonal to Seasonal Prediction (LS4P), this study explores the causality between 2022 May (July) TP LST/SUBT and June (August) precipitation using an ensemble of land–atmosphere coupled model *** show that model prediction with imposed strongly positive May TP LST/SUBT (i.e., a triple) anomaly could produce 67% (46%) of June precipitation anomalies in South (northeast) China, while sea surface temperature (SST) effects account for 5% (51%).The atmosphere condensation heating and surface sensible heating due to TP LST/SUBT anomaly induce anomalous South Asian high, which moves eastward along with the Rossby ***, the above process enhances upward motion, convective instability, and water vapor transport, eventually be favorable for rainfall formation in South China and northeast *** Southeast Asia, it makes a downward movement, decrease in atmospheric water vapor, and unfavorable to the occurrence of ***, July TP LST/SUBT contributes to the prediction skill for August record-breaking drought in southern *** to SST effects, it is found that TP LST/SUBT effects significantly enhance the prediction skill for downstream region, suggesting that the TP land contributes an important source for subseasonal climate prediction. © 2025 American Meteorological Society.

关键词： Rivers

来源：评论

学校读者我要写书评

暂无评论

An Image Semantic Communication system Based on GAN and Relative Position-Encoding

引用

IEEE Communications Letters 2025年

作者： Zhang, Ziqi Tan, Weijie Li, Chunguo Guizhou University College of Big Data and Information Engineering Guiyang550025 China Guizhou University State Key Laboratory of Public Big Data College of Computer Science and Technology Guiyang550025 China Advanced Cryptography and System Security Key Laboratory of Sichuan Province Chengdu610025 China Ministry of Industry and Information Technology Laboratory of Cryptography Application Technology Innovation and Testing Verification Beijing100015 China Southeast University School of Information Science and Engineering Nanjing210096 China

In image semantic communication, the complex wireless channel environment leads to the loss of image details and performance degradation during transmission. To address this issue, we propose an image semantic communication system based on Generative Adversarial Networks (GAN) and Relative Position-Encoding (RPE), named GAN-RpeSC. Specifically, in the system design, we introduce the GAN network at the output of the semantic communication framework to enhance the image restoration. We integrate the RPE module into the Visual Transformer (ViT) module, adding the RPE module to its Multihead Self Attention (MHSA), so that the model can better capture the spatial location information of the image. Experimental results show that the proposed GAN-RpeSC has significant advantages in improving image transmission quality, with a 0.3 dB improvement in peak signal-to-noise ratio (PSNR) compared to the ViT module alone. © 1997-2012 IEEE.

关键词： Encoding (symbols)

来源：评论

学校读者我要写书评

暂无评论

Single Oil Palm Tree Detection and Its Potential Expansion in Honduras

引用

IEEE Transactions on Geoscience and Remote Sensing 2025年 63卷

作者： Zhang, Hang Cui, Yaoping Yu, Le Enrique Corrales Andino, Rafael Zhang, Sen Cui, Kailong Zhao, Tianwei Liang, Han Henan University College of Geographical Sciences Faculty of Geographical Science and Engineering Zhengzhou450046 China Henan University Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions Ministry of Education Kaifeng475004 China Tsinghua University Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System Science Beijing100084 China Tegucigalpa11101 Honduras International Institute for Earth System Sciences Nanjing University Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing210023 China

Honduras is among the ten largest palm oil producers in the world. Accurately detecting the current plantation status and oil palm distribution is crucial to optimize the planting layout. However, current information on single oil palm trees in Honduras is scarce. Here, we used submeter-resolution RGB satellite images in 2022 to detect the spatial distribution and single oil palm tree in Honduras with the four-direction gradient difference (FGD), single-tree feature extraction, and double-ring detection methods. In the accuracy validation zones, the recall, precision, and F1-score metrics for the spatial distribution of oil palm were 86.50%, 86.57%, and 86.53%, respectively;counting accuracy for single oil palm trees was 86.75%;and localization accuracy was approximately 6 m. We estimated 0.25 million hectares (ha) of oil palm plantation area in Honduras, corresponding to 28.27 million trees and an average density of 113 trees/ha. Furthermore, we categorized planted land into highly or moderately suitable zones for future expansion. Among the 0.25 million ha of potentially available land, the highly and moderately suitable zones represented 10 501 and 242 120 ha, respectively, with the potential to carry approximately 28.55 million oil palms. For future oil palm expansion, priority should be given to highly suitable zones. This study not only characterized the distribution and single oil palm properties in Honduras but also suggested potentially suitable zones for future plantation expansion, thereby providing important methodological references and data support to assess the impact of oil palm planting on the ecological environment and socioeconomic aspects at the country scale. © 1980-2012 IEEE.

关键词： Satellite imagery

来源：评论

学校读者我要写书评

暂无评论

Dynamic and static Lagrange multiplier μ based Bayesian CP factorization with orthogonal factors: Theory and applications

引用

Signal Processing 2025年 236卷

作者： Zhou, Jing Zhang, Zhichao School of Mathematics and Statistics Center for Applied Mathematics of Jiangsu Province and Jiangsu International Joint Laboratory on System Modeling and Data Analysis Nanjing University of Information Science and Technology Nanjing210044 China Key Laboratory of System Control and Information Processing Ministry of Education Shanghai Jiao Tong University Shanghai200240 China Key Laboratory of Computational Science and Application of Hainan Province Hainan Normal University Haikou571158 China

The existing μ-Singular Value Decomposition (μ-SVD) denoising algorithm is capable of extracting gear fault information under strong noise conditions. However, this algorithm is only applicable to two-dimensional real-valued data and lacks a mechanism for implementing Automatic Rank Determination (ARD) in high-dimensional data. In this paper, a Bayesian and Tensor treatment of μ-SVD is employed to enable ARD. To further investigate the impact of the Lagrange multiplier μ on the proposed μ-variational Bayesian (μ-VB) algorithm, we examine its performance from both static and dynamic perspectives. Simulation results demonstrate that the μ-VB algorithm achieves ARD and performs well in noise reduction. Further the μ-VB algorithm performs better in wireless communication and linear image coding across numerical domains, tensor sizes, orthogonal factors, and μ settings. © 2025 Elsevier B.V.

关键词： Tensors

来源：评论

学校读者我要写书评

暂无评论

Based on the improved EDCSTFN model, Modis, Landsat 8 and sentinel-2 data were fused to obtain 10m dense time series images

引用

IEEE Access 2025年 13卷 79189-79202页

作者： Chang, Jie Du, Wen Zhang, Bo Guo, Sien Yin, Ying Wang, Zhuo Xu, TongYu Feng, Ziyi College of Information and Electrical Engineering Shenyang Agricultural University Shenyang 110866 China Liaoning Research and Application Center of Remote Sensing of Forest and Grass Resources and Environment University-Enterprise Cooperation for High Resolution Earth Observation System China China National Digital Agriculture Regional Innovation Center (Northeast) China Key Laboratory of Smart Agriculture Technology in Liaoning Province China Liaoning Panjin Wetland Ecosystem National Observation and Research Station Shenyang 110866 China

High-resolution Earth observation data is indispensable for remote sensing applications. However, achieving imagery with both high spatial (10m) and temporal (every 2 days) resolution presents significant challenges due to satellite, technological, and budgetary constraints. This paper introduces a novel approach by integrating MODIS and Sentinel data through an enhanced deep learning framework. The existing Enhanced Deep Convolutional Spatiotemporal Fusion Network (EDCSTFN) is augmented by incorporating multi-scale convolutions within the encoder to more effectively capture Landsat features. Additionally, standard convolutions are supplanted by a residual encoder to facilitate more comprehensive feature extraction.A Squeeze-and-Excitation (SE) channel attention module is integrated to enhance nonlinear processing capabilities and optimize channel interrelationships. These modifications have led to measurable improvements in the model's performance, including an increase in the structural similarity index by 0.2%-0.3% and a reduction in normalized global error by 0.3%-0.4%. The newly developed Modified Integrated Enhanced Deep Convolutional Spatiotemporal Fusion Network (MIEDCSTFN) utilizes the processed Landsat data from EDCSTFN as input for the DSTFN model, generating 10m resolution *** comparative analyses and validation against multiple models confirm the enhanced accuracy and robustness of MIEDCSTFN. The resultant imagery closely approximates actual observations, making significant contributions to remote sensing time-series analysis applications such as crop monitoring, environmental change detection, and resource management. This breakthrough not only holds substantial social value but also offers extensive application potential across diverse fields. © 2013 IEEE.

关键词： 10-meter time-series images EDCSTFN model spatiotemporal fusion

来源：评论

学校读者我要写书评

暂无评论

Graph Chirp Signal and Graph Fractional Vertex-Frequency Energy Distribution

arXiv

引用

arXiv 2025年

作者： Cui, Manjun Zhang, Zhichao School of Mathematics and Statistics The Center for Applied Mathematics of Jiangsu Province The Jiangsu International Joint Laboratory on System Modeling and Data Analysis Nanjing University of Information Science and Technology Nanjing210044 China School of Mathematics and Statistics Nanjing University of Information Science and Technology Nanjing210044 China Key Laboratory of System Control and Information Processing Ministry of Education Shanghai Jiao Tong University Shanghai200240 China Key Laboratory of Computational Science and Application of Hainan Province Hainan Normal University Haikou571158 China

Graph signal processing (GSP) has emerged as a powerful framework for analyzing data on irregular domains. In recent years, many classical techniques in signal processing (SP) have been successfully extended to GSP. Among them, chirp signals play a crucial role in various SP applications. However, graph chirp signals have not been formally defined despite their importance. Here, we define graph chirp signals and establish a comprehensive theoretical framework for their analysis. We propose the graph fractional vertex-frequency energy distribution (GFED), which provides a powerful tool for processing and analyzing graph chirp signals. We introduce the general fractional graph distribution (GFGD), a generalized vertex-frequency distribution, and the reduced interference GFED, which can suppress cross-term interference and enhance signal clarity. Furthermore, we propose a novel method for detecting graph signals through GFED domain filtering, facilitating robust detection and analysis of graph chirp signals in noisy environments. Moreover, this method can be applied to real-world data for denoising more effective than some state-of-the-arts, further demonstrating its practical significance. Copyright © 2025, The Authors. All rights reserved.

关键词： Wiener filtering

来源：评论

学校读者我要写书评

暂无评论

Patterns and drivers of surface cooling effect of urban trees across global cities

引用

Science of the Total Environment 2025年 967卷 178811页

作者： Li, Jiarui Wang, Shasha Zhan, Wenfeng Li, Jiufeng Du, Huilin Li, Long Wang, Chunli Ji, Yingying Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology International Institute for Earth System Science Nanjing University Jiangsu Nanjing210023 China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing210023 China Frontiers Science Center for Critical Earth Material Cycling Nanjing University China

Urban trees offer a promising strategy to mitigating rising heat stress in cities globally. However, the spatial distribution and influencing factors of the tree cooling effect across urban surfaces worldwide are not thoroughly understood. Here we quantified the surface cooling effect during the summer season across 1016 cities globally using two key metrics simultaneously − cooling intensity and cooling distance − primarily based on Landsat-8 land surface temperature data. We then investigated the impact of various drivers on the surface cooling effect, including tree attributes at the small scale (e.g., area and landscape shape index), urban characteristic at the medium scale (e.g., city population), and background climate at the large scale (e.g., air temperature and precipitation). Furthermore, the combined effects of urban and climatic contexts on the regulation of tree attributes on the surface cooling effect were examined. Our findings reveal that the global average cooling intensity is 1.67 ± 1.13 °C, while the global average cooling distance is 136.86 ± 60.44 m. Cooling intensity is mainly regulated by tree attributes (88 %), followed by background climate (9 %) and urban characteristic (3 %). The variable that explains the most variation in cooling intensity is the NDVI of trees at the small scale. Similarly, the cooling distance is primarily influenced by tree attributes (73 %), background climate (22 %), and urban characteristic (5 %). The area of trees at the small scale is the primary factor contributing to the variation in cooling distance. Additionally, the impact of tree attributes on cooling effect is jointly moderated by urban characteristic and background climate. In cities with larger populations or higher air temperatures, the area of trees and the landscape shape index exert a less pronounced impact on the cooling effect. This implies that the presence of small, widely dispersed tree cover in such urban areas can effectively provide the coolin

关键词： Land surface temperature

来源：评论

学校读者我要写书评

暂无评论

Diode-pumped ring-cavity-dumped few-nanosecond single-longitudinal-mode Alexandrite laser

引用

Optics Letters 2025年第10期50卷 3457-3460页

作者： Jingchong Wang Shiwu Wang Zhenhua Cong Gaoyou Liu Chen Guan Zhigang Zhao Zhaojun Liu School of Information Science and Engineering Shandong University Qingdao 266237 China Key Laboratory of Laser and Infrared System Ministry of Education Shandong University Qingdao 266237 China Crystech Co. Ltd. Qingdao 266000 China Shandong Provincial Key Laboratory of Laser Technology and Application Qingdao 266000 China Laser Institute Qilu University of Technology (Shandong Academy of Sciences) Jinan 250000 China zhigang@***

A red laser diode (LD) pumped single-longitudinal-mode (SLM) short-pulsed Alexandrite laser with a pulse duration of a few nanoseconds is presented, in which the cavity-dumping technique is for the first time, to our knowledge, introduced into the unidirectional ring cavity. For continuous-wave (CW) operation, a SLM Alexandrite laser with wavelength tunability from 735 nm to 786 nm was realized, and the maximum output power was 1.03 W at 759 nm. In the ring-cavity-dumped configuration, a pulsed SLM 770.6-nm Alexandrite laser was demonstrated, with a pulse energy of 12.1 µJ, a pulse duration of 7.8 ns, and a linewidth of 727 MHz at 1-kHz repetition rate. The corresponding beam quality factors were measured to be ${\rm M}_{\rm x}^{2}$ = 1.14 and ${\rm M}_{\rm y}^{2}$ = 1.09. When the repetition rate was increased to 10 kHz, the output power went up to 89 mW.

关键词： Diode lasers Laser beams Laser crystals Light emitting diodes Nonlinear frequency conversion Ring lasers

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：