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A high-resolution dataset for lower atmospheric process studies over the Tibetan Plateau from 1981 to 2020

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Big Earth Data 2024年第3期8卷 540-565页

作者： fei li Shupo Ma Jinhuan Zhu Han Zou Peng li libo Zhou Department of Lower Atmospheric Observation Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina

ABSTRACT A high-resolution meteorological dataset(≤10 km)over the Tibetan Plateau(TP)is the foundation for investigating and predicting the weather and climate over *** TP Subregional Dynamical Downscaling(TPSDD)dataset is a newly developed high-spatial-temporal resolution gridded dataset for land‒air exchange pro-cesses and lower atmospheric structure studies over the whole TP region,taking the climate characteristics of each TP subregion into *** dataset spans from 1981 to 2020,covering the TP with a temporal resolution of 2 hr and spatial resolution of 10 *** elements of the dataset include near-surface land-air exchange parameters,such as downward/upward long-wave/shortwave radiation flux,sensible heat flux,latent heat flux,*** addition,the vertical distributions of 3-dimensional wind,temperature,humidity,and pressure from the surface to the lower stratosphere are also *** evaluations were con-ducted to verify the performance of the TPSDD dataset by compar-ing TPSDD/reanalysis with surface and vertical observations through the calculation of statistical *** results demonstrate the accuracy and superiority of this dataset against reanalysis data,which provides great potential for future climate change research.

关键词： Tibetan Plateau WRF model dynamical downscaling land‒air interaction the lower atmosphere

DeepGCN based on variable multi‐graph and multimodal data for ASD diagnosis

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CAAI Transactions on Intelligence Technology 2024年第4期9卷 879-893页

作者： Shuaiqi liu Siqi Wang Chaolei Sun Bing li Shuihua Wang fei li College of Electronic and Information Engineering Hebei UniversityBaodingChina Machine Vision Technology Innovation Center of Hebei Province BaodingChina The State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of AutomationChinese Academy of SciencesBeijingChina School of Computer Science and Technology Henan Polytechnic UniversityJiaozuoChina

Diagnosing individuals with autism spectrum disorder(ASD)accurately faces great chal-lenges in clinical practice,primarily due to the data's high heterogeneity and limited sample *** tackle this issue,the authors constructed a deep graph convolutional network(GCN)based on variable multi‐graph and multimodal data(VMM‐DGCN)for ASD ***,the functional connectivity matrix was constructed to extract primary ***,the authors constructed a variable multi‐graph construction strategy to capture the multi‐scale feature representations of each subject by utilising convolutional filters with varying kernel ***,the authors brought the non‐imaging in-formation into the feature representation at each scale and constructed multiple population graphs based on multimodal data by fully considering the correlation between *** extracting the deeper features of population graphs using the deep GCN(DeepGCN),the authors fused the node features of multiple subgraphs to perform node classification tasks for typical control and ASD *** proposed algorithm was evaluated on the Autism Brain Imaging Data Exchange I(ABIDE I)dataset,achieving an accuracy of 91.62%and an area under the curve value of 95.74%.These results demon-strated its outstanding performance compared to other ASD diagnostic algorithms.

关键词： machine learning medical image processing medical signal processing

Hole-Transporting Materials with Rational Combination of Pyridine and Dibenzo[a,c]phenazine as Electron Acceptor for Dopant-Free Perovskite Solar Cells

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Chinese Journal of Chemistry 2024年第10期42卷 1100-1106页

作者： Weidong ling fei Wu Wentao Yuan linna Zhu Qianqian li Zhen li Hubei Key Lab on Organic and Polymeric Opto-Electronic Materials Department of ChemistryWuhan UniversityWuhanHubei 430072China Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energy Faculty of Materials&EnergySouthwest UniversityChongqing400715China TaiKang Center for life and Medical Sciences Wuhan UniversityWuhanHubei 430072China

Perovskite solar cells(PSCs)have been proven to be a promising option for photovoltaic *** the aim to achieve efficient and stable PSCs,it is essential to explore dopant-free hole-transporting materials(HTMs)with high hole ***,HTMs bearing electron donor(D)-electron acceptor(A)-electron donor(D)structures have been constructed with strong intramolecular charge transfer(ICT)effect,based on rational combination of dibenzo[a,c]phenazine and pyridine as electronic acceptors and anchoring groups to perovskite ***,high hole mobility(7.31×10^(-5) cm^(2)·V^(-1)·s^(-1))and photoelectric conversion efficiency(20.45%)have been achieved by dopant-free DPyP-based *** afforded an efficient way to design HTMs with high hole mobility by adjustment of molecular configurations and electronic property of conjugated systems.

关键词： Perovskite solar cell Charge transfer Donor-acceptor systems Energy conversion Hole mobility

Bimetal MOF-derived NiFe-P nanocomposites coupled with Cu_(3)P nanoparticles to construct tandem electron transfer channels for photocatalytic hydrogen evolution

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Journal of Environmental Sciences 2024年第3期137卷 333-346页

作者： Haiyan Zhang Shitao Yang Peng Zhu Senpei tang Ming li College of Chemistry and Chemical Engineering Jishou UniversityJishou 416000China School of Account Hunan University of Technology and BusinessChangsha 410205China

Finely modulated light-induced charge separation and transfer is a central challenge to achieve efficient *** progress has been made in this field,most of the previous research works focused on the separation or migration of photogenerated carriers but did not build a bridge between the *** to realize the strong driving and precise migration of carriers has become the focus of our *** report an ingeniously designed ternary *** NiFe-MOF as the“parent material”,the FeP_(4)/Ni_(x)P_(y)heterojunction is derived in situ while maintaining the frame structure through gas-solid reaction,and finally the Z-type electron transfer is *** Cu_(3)P anchoring spindle matrix,an electron transport tunnel is opened up in Cu_(3)P/FeP_(4)/Ni_(x)P_(y)ternary heterojunction under the action of p-n heterojunction built-in electric field driving and accurate energy band *** strong driving force of the built-in electric field provides an inexhaustible power for the transmission of electrons,and the fine series of electron transmission channels realizes the precise transmission of *** above fine design makes the perfect fit between the built-in electric field and the electron transfer channel,which not only effectively improves the embarrassing situation of insufficient electron driving force of hydrogen evolution reaction in the previous research,but also makes up for the weakening of semi-conductor reduction ability caused by the construction of traditional p-n *** research work provides a new idea for the construction of multiple heterostructures and the design of fine interface engineering in the future.

关键词： Cu_(3)P/FeP_(4)/Ni_(x)P Built-in electric field Electron transfer channels Photocatalysis

维普期刊数据库

Joint position optimization,user association,and resource allocation for load balancing in UAV-assisted wireless networks

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Digital Communications and Networks 2024年第1期10卷 25-37页

作者： Daosen Zhai Huan li Xiao tang Ruonan Zhang Haotong Cao School of Electronics and Information Northwestern Polytechnical UniversityXian710072China State Key Laboratory of Integrated Services Networks Xidian UniversityXian710071China Department of Computing Hong Kong Polytechnic UniversityHong Kong SARChina

Unbalanced traffic distribution in cellular networks results in congestion and degrades spectrum *** tackle this problem,we propose an Unmanned Aerial Vehicle(UAV)-assisted wireless network in which the UAV acts as an aerial relay to divert some traffic from the overloaded cell to its adjacent underloaded *** fully exploit its potential,we jointly optimize the UAV position,user association,spectrum allocation,and power allocation to maximize the sum-log-rate of all users in two adjacent *** tackle the complicated joint optimization problem,we first design a genetic-based algorithm to optimize the UAV ***,we simplify the problem by theoretical analysis and devise a low-complexity algorithm according to the branch-and-bound method,so as to obtain the optimal user association and spectrum allocation *** further propose an iterative power allocation algorithm based on the sequential convex approximation *** simulation results indicate that the proposed UAV-assisted wireless network is superior to the terrestrial network in both utility and throughput,and the proposed algorithms can substantially improve the network performance in comparison with the other schemes.

关键词： Load balance Unmanned aerial vehicle Userassociation Resource management

Effective Ultra-High-Speed Identification Scheme of lightning Strikes Suitable for VSC-Based DC Grids

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 548-561页

作者： Longlong Chen Xiangyu Pei Xiaoguang Wei Pengzhi li Guangfu tang North China Electric Power University(NCEPU) Beijing 102206China Changsha University of Science and Technology Changsha 410114China State Key Laboratory of Advanced Power Transmission Technology State Grid Smart Grid Research Institute Co.Ltd.Beijing 102209China

To ensure their sound and continuous operation to the greatest extent,VSC-based DC girds have extremely stringent requirements for transmission line relay *** terms of guaranteeing their reliability,accurate identification of lightning strikes on DC transmission lines is one of the urgent key problems to be *** effective ultra-high-speed identification scheme of lightning strikes suitable for the VSC-based DC grid is proposed in this ***,an 1-mode reverse voltage traveling wave(RVTW)is constructed applying the pole-mode transformation ***,fault traveling wave propagation characteristics along the DC transmission line are analyzed in depth utilizing Peterson's ***,differences of time-frequency electromagnetic transient characteristics of 1-mode RVTWs between disturbances and faults caused by lightning strikes are distinguished in detail by means of the classical wavelet transformation multi-resolution analysis ***,extensive simulations are carried out to evaluate the performance of the proposed identification scheme,and by which its excellent rapidity,reliability and robustness are *** Terms-lightning-strike identification,Multi-resolution analysis,Relay protection,Traveling-wave protection,VsC-based DC grid,Wavelet transformation.

关键词： lightning-strike identification Multi-resolution analysis Relay protection Traveling-wave protection VsC-based DC grid Wavelet transformation

Optimal Planning of Hybrid AC/DC Low-voltage Distribution Networks Considering DC Conversion of Three-phase Four-wire Low-voltage AC Systems

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 141-153页

作者： Bo Zhang Lu Zhang Wei tang Gen li Chen Wang the College of Information and Electrical Engineering China Agricultural UniversityBeijing 100083China the Electric Energy Group Department of Engineering TechnologyTechnical University of Denmark(DTU)2750 BallerupDenmark the Power Distribution Technology Center State Grid Beijing Electric Power Research InstituteBeijing 100075China

The increasing integration of distributed household photovoltaics(PVs)and electric vehicles(EVs)may further ag gravate voltage violations and unbalance of low-voltage distribu tion networks(LVDNs).DC distribution networks can increase the accommodation of PVs and EVs and mitigate mutilple pow er quality problems by the flexible power regulation capability of voltage source *** paper proposes schemes to es tablish hybrid AC/DC LVDNs considering the conversion of the existing three-phase four-wire low-voltage AC systems to DC op *** characteristics and DC conversion constraints of typical LVDNs are *** addition,converter configura tions for typical LVDNs are proposed based on the three-phase four-wire characteristics and quantitative analysis of various DC ***,an optimal planning method of hybrid AC/DC LVDNs is proposed,which is modeled as a bi-level programming model considering the annual investments and three-phase *** are conducted to verify the effectiveness of the proposed optimal planning *** ulation results show that the proposed optimal planning method can increase the integration of PVs while simultaneously reduc ing issues related to voltage violation and unbalance.

关键词： Optimal planning low-voltage distribution net work three-phase unbalance DC conversion

维普期刊数据库

Exploring the mechanisms of calcium carbonate deposition on various substrates with implications for effective anti-scaling material selection

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Petroleum Science 2024年第4期21卷 2870-2880页

作者： Lu Gong fei-Yi Wu Ming-fei Pan Jun Huang Hao Zhang Jing-li Luo Hong-Bo Zeng College of Science China University of Petroleum Beijing Key Laboratory of Optical Detection Technology for Oil and Gas China University of Petroleum Basic Research Center for Energy Interdisciplinary College of Science China University of Petroleum Department of Chemical and Materials Engineering University of Alberta Key Laboratory of High Efficiency and Clean Mechanical Manufacture (Ministry of Education) School of Mechanical Engineering Shandong University

The unexpected scaling phenomena have resulted in significant damages to the oil and gas industries,leading to issues such as heat exchanger failures and pipeline clogging. It is of practical and fundamental importance to understand the scaling mechanisms and develop efficient anti-scaling strategies. However,the underlying surface interaction mechanisms of scalants(e.g., calcite) with various substrates are still not fully understood. In this work, the colloidal probe atomic force microscopy(AFM) technique has been applied to directly quantify the surface forces between calcite particles and different metallic substrates,including carbon steel(CR1018), low alloy steel(4140), stainless steel(SS304) and tungsten carbide,under different water chemistries(i.e., salinity and p H). Measured force profiles revealed that the attractive van der Waals(VDW) interaction contributed to the attachment of the calcium carbonate particles on substrate surfaces, while the repulsive electric double layer(EDL) interactions could inhibit the attachment behaviors. High salinity and acidic p H conditions of aqueous solutions could weaken the EDL repulsion and promote the attachment behavior. The adhesion of calcite particles with CR1018 and4140 substrates was much stronger than that with SS304 and tungsten carbide substrates. The bulk scaling tests in aqueous solutions from an industrial oil production process showed that much more severe scaling behaviors of calcite was detected on CR1018 and 4140 than those on SS304 and tungsten carbide, which agreed with surface force measurement results. Besides, high salinity and acidic p H can significantly enhance the scaling phenomena. This work provides fundamental insights into the scaling mechanisms of calcite at the nanoscale with practical implications for the selection of suitable antiscaling materials in petroleum industries.

关键词： Scaling phenomenon Metallic substrates Surface forces Bulk scaling tests

Extracting Integrated Features of Electronic Medical Records Big Data for Mortality and Phenotype Prediction

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Chinese Journal of Electronics 2024年第3期33卷 776-792页

作者： fei li Yiqiang CHEN Yang GU Yaowei WANG Institute of Computing Technology University of Chinese Academy of Sciences Pengcheng Laboratory

The key to synthesizing the features of electronic medical records(EMR) big data and using them for specific medical purposes,such as mortality and phenotype prediction,is to integrate the individual medical event and the overall multivariate time series feature extraction automatically,as well as to alleviate data imbalance *** paper provides a general feature extraction method to reduce manual intervention and automatically process large-scale *** processing uses two variational auto-encoders(VAEs) to automatically extract individual and global *** avoids the well-known posterior collapse problem of Transformer VAE through a uniquely designed "proportional and stabilizing" mechanism and forms a unique means to alleviate the data imbalance *** conducted experiments using ICU-STAY patients' data from the MIMIC-Ⅲ database and compared them with the mainstream EMR time series processing *** results show that the method extracts visible and comprehensive features,alleviates data imbalance problems and improves the accuracy in specific predicting tasks.

关键词： Databases Time series analysis MIMICs Manuals Big Data Feature extraction Transformers