检索结果-内蒙古大学图书馆

Earth Fault Detection Method for TN-C Systems Based on Comparison of Current Deviations

IEEE TRANSACTIONS ON POWER DELIVERY 2025年第2期40卷 1191-1202页

作者： sun, zhongyu Xu, Bingyin Wang, Wei Yip, Tony Shandong Univ Sch Elect Engn Jinan 250061 Peoples R China Shandong Univ Technol Sch Elect & Elect Engn Zibo 255000 Peoples R China Kehui Int Ltd Hertford SG13 7GX England

The existing low voltage (LV) earth fault detection techniques using residual current measurements cannot be effectively applied to the multi-earthed TN-C system. When an earth fault occurs on the multi-earthed TN-C system, the fault current passes through the combined protective and neutral (PEN) conductor back to the source, resulting in a low residual current. However, unbalanced load switching also generates residual current through the same path back to the source, thus making fault discrimination very difficult. To address this problem, the four-wire multi-earthed TN-C system was analyzed by decoupling the mode 0 and the mode N of the equivalent circuit so that the current characteristics can be clearly studied. A new earth fault detection method is developed which compares the residual current deviation with the PEN conductor current deviation. The scheme uses amplitude ratio and phase angle difference between these two measurements to discriminate between earth faults and unbalanced load switching. The feasibility of the proposed method was verified by digital simulation and by physical tests in an actual LV distribution network. Compared to approaches based only on residual current, the proposed method demonstrates better sensitivity and reliability.

关键词： Conductors Circuit faults Switches Fault detection Impedance Voltage Grounding Current measurement Distribution networks Artificial intelligence Earth fault detection equivalent circuits low voltage (LV) distribution networks multi-earthed TN-C systems unbalanced load switching

来源：评论

学校读者我要写书评

暂无评论

The impact of economic policy uncertainty on household portfolios effectiveness: Evidence from China

引用

FINANCE RESEARCH LETTERS 2025年 78卷

作者： sun, zhongyu Li, Jun Hunan Normal Univ Sch Math & Stat Changsha 410081 Hunan Peoples R China Hunan Normal Univ Sch Business Changsha 410081 Hunan Peoples R China

This paper uses the text analysis method to construct the provincial level economic policy uncertainty index in China, and matches the index with China's micro household data to empirically test the impact and mechanism of economic policy uncertainty on the effectiveness of household portfolios. We find that economic policy uncertainty significantly reduces the effectiveness of household portfolios, and reducing risk preference and increasing income risk are important mechanisms. Finally, we also conduct moderating effect analysis and find that marketization, financial development and financial literacy can effectively moderate the impact of economic policy uncertainty on household portfolios.

关键词： Economic policy uncertainty Household portfolios effectiveness Risk preference Income risk

来源：评论

学校读者我要写书评

暂无评论

A Comprehensive Framework for Evaluating Cycling Infrastructure: Fusing Subjective Perceptions with Objective Data

引用

SENSORS 2025年第4期25卷 1168页

作者： Tian, Kefei Zheng, Yifan sun, zhongyu Yin, Zishun Zhu, Kai Liu, Chenglong Tongji Univ Key Lab Rd & Traff Engn Minist Educ Shanghai 201804 Peoples R China

As cities increasingly prioritize green and low-carbon transportation, the development of effective cycling infrastructure has become essential for alleviating traffic congestion and reducing environmental impacts. However, the service quality of bike lanes remains inadequate. To address this gap, this study proposes a multi-data-fusion framework for evaluating bike lane "cycling friendliness", integrating subjective perceptions with objective metrics. The framework combines survey-based subjective data with digital measurements to enable rapid, large-scale assessments that align with user expectations. Tailored evaluation models are developed based on revealed preference (RP) survey analysis to account for variations among target user groups. Key factors such as road roughness, motor vehicle encroachment, cycling-friendly amenities, and roadside scenery are quantitatively assessed using vibration analysis and computer vision techniques. Validation results reveal a strong correlation between model predictions and subjective evaluations, demonstrating the framework's reliability and effectiveness. This approach offers a scalable, data-driven tool for optimizing bike route selection and guiding infrastructure upgrades, thus advancing urban cycling transportation.

关键词： cycling friendliness evaluation multi-data fusion vibration signal processing computer vision reveal preference survey

来源：评论

学校读者我要写书评

暂无评论

Characterizing key foliar functional traits of subtropical evergreen forests in South China using leaf and UAV-based spectroscopy

引用

COMPUTERS AND ELECTRONICS IN AGRICULTURE 2025年 233卷

作者： Wang, Zhihui sun, zhongyu Liu, Nanfeng Geng, Shoubao Wen, Meili Zhang, Hui Yang, Long Guangdong Acad Sci Guangzhou Inst Geog Guangdong Prov Key Lab Remote Sensing & Geog Infor Guangdong Open Lab Geospatial Informat Technol & A Guangzhou 510070 Peoples R China Sun Yat Sen Univ Sch Geog & Planning Guangdong Prov Key Lab Urbanizat & Geosimulat Guangzhou 510275 Peoples R China Hainan Univ Coll Forestry Wuzhishan Natl Long Term Forest Ecosyst Monitoring Haikou 570228 Peoples R China Hainan Univ Minist Educ Coll Forestry Key Lab Genet & Germplasm Innovat Trop Special For Haikou 570228 Peoples R China

Spectroscopy provides an efficient way of predicting foliar functional traits at both leaf and canopy scales. Previous studies mainly used hyperspectral data from airborne and spaceborne platforms, and few studies assessed the feasibility of the more cost-effective and flexible unmanned airborne vehicle (UAV) -based imaging spectroscopy. Moreover, the research was mainly conducted in temperate and tropical biome, with less attention to subtropical evergreen forests. This study aims to characterize key foliar functional traits of subtropical evergreen forests in South China using leaf and UAV-based spectroscopy data. Dry and fresh leaf spectra as well as key foliar functional traits (leaf chlorophyll and carotenoids, water, dry matter, nitrogen, phosphorus, and potassium) were collected from 360 samples over 97 species across four field sites. For the site Heshan, we also collected UAV-based hyperspectral imageries at two dates. Partial least squares regression (PLSR) and random forest regression (RF) were used to link foliar traits with dry leaf spectra, fresh leaf spectra and canopy spectra, respectively. Cross-site and cross-season validations were performed to assess model transferability. Results showed that dry and fresh leaf spectra could estimate most foliar traits with comparable accuracies (normalized RMSE (NRMSE) < 20 %). Leaf trait models can be transferred across sites and species. Canopy models could provide accurate estimations of pigments, N-mass, N-area, C/N and N/P (NRMSE = 12.92 - 21.02 %), but had low transferability across seasons due to phenological differences in both foliar traits and canopy spectra. PLSR outperformed RF in predicting foliar traits with leaf spectra, whereas RF achieved better estimations at the canopy scale. Trait maps from PLSR and RF were consistent, and both can capture the seasonal variation of foliar traits. We conclude that in-situ measurements covering the variability of foliar functional traits and spectra are needed

关键词： Foliar functional trait Hyperspectral remote sensing UAVs Leaf spectroscopy Model transferability Subtropical evergreen forest

来源：评论

学校读者我要写书评

暂无评论

CoOx/CeO2@C nanopetals derived Cobalt-Cerium Prussian blue with enhanced Dual-Enzyme mimetic activity for detection of ascorbic acid in rat brain during calm/ischemic processes

引用

TALANTA 2025年 286卷 127445页

作者： Ding, Yongqi Zhao, Rufang Chen, Jianmei sun, zhongyu Yan, Bowen Wang, Yuxin Zheng, Bozhao Hubei Normal Univ Coll Chem & Chem Engn Hubei Key Lab Pollutant Anal & Reuse Technol Huangshi 435002 Peoples R China Shandong First Med Univ Med Sci & Technol Innovat Ctr Jinan 250000 Peoples R China Shandong Acad Med Sci Jinan 250000 Peoples R China

In this study, we demonstrate that a highly efficient colorimetric sensor prepared from carbon-shielded Co-Ce Prussian blue analog (PBA) nanopetals (CoOx/ CeO2@C) by green chemical deposition method and thermal annealing processes for detection of ascorbic acid (AA) in cerebral microdialysis fluids. The synthesized CoOx/CeO2@C showed high dual-mimetic activity, i.e., peroxidase- and catalase-like activity, and great catalytic stability. The combination of carbon film and Co-Ce PBA nanopetals (1) greatly enhances the interfacial electron transfer rate of the nanopetals due to excellent electrical conductivity of carbon, and (2) protects nanopetals from acidic chemical environments during the catalytic process, which greatly reduces loss of the catalytic activity of the cobalt-cerium (hydroxide) oxides. Based on the peroxidase-like property of CoOx/CeO2@C nanopetals, this sensor has a good linear range from 0.1 to 150 mu M with a low detection limit of 0.04 mu M, i.e., improved sensitivity for AA colorimetric measurement. The developed colorimetric strategy with a green synthetic pathway, catalytic stability and wide linear range confirms the monitoring of AA in brain systems during calm/ischemic processes.

关键词： Ascorbic acid

来源：评论

学校读者我要写书评

暂无评论

Recursive Neural Network: Small Target Detection in Remote Sensing Images 17th

Recursive Neural Network: Small Target Detection in Remote S...

引用

17th International Conference on Intelligent Robotics and Applications

作者： Yu, Changlin Zhang, Juchao sun, zhongyu Pang, Zaixiang Xu, Changxian sun, Zhongbo Changchun Univ Technol Dept Control Engn Changchun 130012 Peoples R China Acad Sci Guangzhou Inst Geog Guangdong Open Lab Geospatial Informat Technol & Guangzhou 510070 Guangdong Peoples R China

ISBN: (纸本)9789819607945;9789819607952

In this paper, a novel remote sensing image object detection algorithm is proposed by combining constraint energy minimization (CEM) and noise tolerance zeroing neural network (NTZNN). This algorithm combines traditional image processing methods with recursive neural network (RNN) and proposes a multi scene usable NTZNN-CEM object detection model for hyperspectral and RGB remote sensing images. Finally, through numerical simulation experiments and remote sensing image object detection experiments, it has been proven that the NTZNN-CEM algorithm has advantages such as fast detection speed and strong robustness, providing a new visual approach for improving the advanced perception of robots in complex environments.

关键词： Recursive neural network Remote sensing image Object detection

来源：评论

学校读者我要写书评

暂无评论

Incipient Fault Detection of Medium-Voltage Distribution Cable Systems Using Time-Frequency Analysis of Grounding Wire Currents

引用

IEEE TRANSACTIONS ON SMART GRID 2025年第1期16卷 74-86页

作者： Zhang, Peng Hou, Meng Liang, Rui Tang, Zehua Li, Jian Jin, Mohan sun, zhongyu Peng, Nan China Univ Min & Technol Sch Elect Engn Xuzhou 221116 Peoples R China Kings Coll London Dept Engn London WC2R 2LS England Shandong Univ Sch Elect Engn Jinan 250061 Peoples R China

Incipient cable faults pose a significant risk to the normal operation of power grids. Addressing the issue of detecting incipient faults in underground cables is particularly difficult due to their hidden external characteristics that are not easily observable. Furthermore, these faults occur randomly, with short durations, which further complicates their detection. This paper firstly establishes a cable field-circuit equivalent model that considers multi-conductor electromagnetic coupling for incipient faulty scenarios. The mathematical relationship between the grounding wire currents (GWCs) and fault conditions is then theoretically deduced specifically. A novel method is developed to detect incipient faults in three-core cables by analyzing the time-frequency characteristics of GWC frequency components considering the time-varying fault resistance. The simulation results demonstrate the effectiveness and robustness of the proposed method, showing little impact from fault initial conditions, disturbances, and distributed generations (DGs). Finally, the method is verified in an actual 10 kV distribution network.

关键词： Incipient fault detection transient equivalent model time-varying resistance grounding wire current Incipient fault detection transient equivalent model time-varying resistance grounding wire current

来源：评论

学校读者我要写书评

暂无评论

Lead alters the tolerance of dominant woody plants in subtropical coastal zones to flash drought

引用

MARINE POLLUTION BULLETIN 2025年 216卷 117959页

作者： Yi, Yuankai sun, zhongyu Zhang, Shike Wei, Long Liu, Jing Liu, Nan Chinese Acad Sci Guangdong Prov Key Lab Appl Bot South China Bot Garden Guangzhou 510650 Peoples R China Guangzhou Inst Geog Guangdong Acad Sci Greater Bay Area Urban Agglomerat Ecosyst Observat Guangzhou 510070 Peoples R China Guangdong Acad Forestry Guangdong Prov Key Lab Silviculture Protect & Util Guangdong Coastal Shelterbelt Ecosyst Natl Observa Guangzhou 510520 Peoples R China Chinese Acad Sci Inst Genet & Dev Biol Key Lab Seed Innovat Beijing 100101 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

Under the influence of climate change and human activities, drought and heavy metal pollution are increasingly threatening the stability of coastal regions. In this study, the ecophysiological responses of three representative coastal plant species (Hibiscus tiliaceus, Barringtonia racemosa, and Terminalia neotaliala) in subtropical regions to lead addition (Pb), drought stress (D), their co-existence (Pb + D), and control (CK) were investigated. The results showed that, compared to CK, Pb treatment alone did not significantly affect plant growth during the experiment, which lasted for 8 days. In contrast, both D and Pb + D treatment caused a notable negative impact, with significant increases in abscisic acid (ABA), proline (PRO), and superoxide anion (O-2(-)) levels and a significant decrease in net photosynthetic rates (Pn). In addition to the comparison with CK, we also observed a distinction between the effects of Pb + D treatment and those of either Pb treatment or D treatment. With Pb + D treatment, Pb accumulation in the roots and leaves of H. tiliaceus and B. racemosa and in the roots of T. neotaliala was higher than those with Pb treatment alone. Other than that, the negative impacts in growth of Pb + D treatment appeared to be delayed compared to the D treatment alone. Moreover, B. racemosa demonstrated good tolerance to Pb, drought and their co-existence treatments, indicating its potential for use in coastal vegetation restoration to enhance ecosystem resilience and stability in subtropical regions.

关键词： Global climate change Industrial hazards Morphological traits Physiological indicators

来源：评论

学校读者我要写书评

暂无评论

Smartphone-Integrated Colorimetric Sensor Based on Cecu–Mofs Nanozymes with Enhanced Triple-Enzyme Mimetic Activity

SSRN

引用

SSRN 2025年

作者： Ding, Yongqi Chen, Jianmei Zhou, Nengjing Huang, Xin sun, zhongyu Hubei Key Laboratory of Pollutant Analysis and Reuse Technology College of Chemistry and Chemical Engineering Hubei Normal University Huangshi435002 China School of Chemistry and Materials Science Jiangsu Normal University 101 Shanghai Road Xuzhou221116 China

Metal-organic frameworks (MOFs) are often acted as potential candidates for the construction of efficient nanozymes due to their unique metal-ligand assembly structure, which can mimic different enzyme activities by modulating the metal nodes and ligand environment. In this study, a three-in-one composite metal-organic framework nanozymes (CeCu–MOFs) with excellent intrinsic peroxidase, oxidase and catalase-like catalytic properties have been successfully prepared in environmentally friendly manner by a one-step chemical deposition method. Meanwhile, a catalytic platform for signal amplification was designed for quantitative measurement of ascorbic acid (AA) using oxidase-like characteristic of CeCu–MOFs. The constructed colorimetric sensor achieved selective identification and accurate measurement of AA, demonstrated good linearity in the range of 1-50 μM with detection limit of 0.063 μM, and further developed a portable smartphone platform for visual colorimetric analysis of AA in real samples in point-of-care (POC) fashion by utilizing a portable paper-based device. © 2025, The Authors. All rights reserved.

关键词： Ligands

来源：评论

学校读者我要写书评

暂无评论

无人机植被遥感中可见光相机色温对植被指数计算的影响

引用

应用生态学报 2025年第3期36卷 729-737页

作者：许静杨龙王俊坚孙中宇广东省科学院广州地理研究所广州510070 南方科技大学环境科学与工程学院广东深圳518055 广东省遥感与地理信息系统应用重点实验室广州510070 粤港澳大湾区城市群生态系统观测研究站广州510070

以RGB三波段光谱信息为基础计算的植被指数已被广泛应用于无人机植被遥感领域。受到相机自动色温调节的影响,无人机获取RGB影像时常存在偏色现象,但该现象对植被指数计算产生的影响目前仍缺乏关注。本研究分析了5000~8000 K色温梯度下... 详细信息

以RGB三波段光谱信息为基础计算的植被指数已被广泛应用于无人机植被遥感领域。受到相机自动色温调节的影响,无人机获取RGB影像时常存在偏色现象,但该现象对植被指数计算产生的影响目前仍缺乏关注。本研究分析了5000~8000 K色温梯度下非植被地物、针叶树种、阔叶树种和草本植物的13种植被指数的变化趋势。结果表明:色温改变显著影响可见光植被指数的计算结果。随着色温的升高,13种植被指数表现出上升、下降、单峰、稳定和波动5种变化趋势。归一化蓝绿差异指数、过绿指数、归一化红绿差异指数、修改后的归一化绿红差异指数、可见光大气阻抗指数、蓝绿比植被指数、蓝红比植被指数、改进型双绿度指数和绿度百分比指数随色温变化的趋势既不受地物类别的影响也不受物种种类的影响;三角绿度指数、绿叶指数和红绿蓝植被指数随色温变化的趋势受到地物类别和物种种类的双重影响,归一化蓝色指数随色温变化的趋势受地物类别但不受物种种类的影响。同一植被指数的种间差异会因色温的升高而被放大。影像拍摄时的天气情况是影响数据质量的关键因素。运用无人机RGB影像计算的植被指数阐释生态学规律时,需要对数据采集端进行严格的质量把控,否则得到的结果可能会因色温的影响而失去应有的解释力。

关键词：植被指数白平衡无人机色温可见光

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：