检索结果-内蒙古大学图书馆

作者： LIU, Yanhai chen, xuwen LI, Guangju ZHANG, Dongliang

标准号: EP4044404(A4)

The present invention provides a concentrated winding axial cooling motor stator and a motor. The above concentrated winding axial cooling motor stator includes barriers and an axial oil feeding device, the barriers are in contact with stator windings and plug notches of a stator core, and the barrier and coils of two adjacent groups of the stator windings in slots of the stator core constitute a cooling medium communication cavity;the axial oil feeding device is arranged at any end part of the stator cores or is connected with a casing, and a location of the axial oil feeding device corresponds to any end of the stator cores;a side of the axial oil feeding device close to the stator windings is provided with a spray hole, an axis of the spray hole and an axis of the stator winding are intersected obliquely, a cooling medium is sprayed to the barrier and/or the stator winding and thus flows along an axial inner surface of the stator winding towards two ends of the stator winding. The present invention has the beneficial effect that the axial oil feeding device is arranged at a leading-out terminal or a non-leading-out terminal of a motor stator, thereby improving a heat exchange contact area between the cooling medium and the winding, and increasing heat dissipation capability.

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Finer soil properties mapping framework for broad-scale area: A case study of Hubei Province, China

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GEODERMA 2024年 449卷

作者： Wang, Ruizhen chen, Weitao chen, Hao Qin, xuwen China Univ Geosci Key Lab Geol Survey & Evaluat Minist Educ Wuhan 430074 Peoples R China China Univ Geosci Fac Comp Sci Wuhan 430074 Peoples R China Minist Educ Engn Res Ctr Nat Resource Informat Management & Di Wuhan 430074 Peoples R China China Geol Survey China Aero Geophys Survey & Remote Sensing Ctr Nat Beijing 100083 Peoples R China

Fine-scale spatial distribution of soil physicochemical properties is crucial for soil quality management, agriculture planning and geotechnical engineering. Existing soil map databases are usually developed in national scale, potentially leading to issues of coarse resolution and restricted applicability in fine-scaled studies. For broad-scale area, conventional digital soil mapping methods are challenging due to the lack of representative soil profiles and their uneven distribution. This study addresses these challenges by developing a downscaling-based framework to map 11 soil physicochemical properties at a 30-m resolution. The methodology involves constructing regression models using soil properties derived from coarse national soil maps and soil-forming covariates. Predictions are subsequently refined using fine-resolution covariates. To capture fine-scale spatial variability across diverse landscapes, 30-m resolution remote sensing data, relief, climate, and spatial covariates were prepared. The fine-gridding framework employs tree-based machine learning models, particularly random forest (RF), to enhance prediction accuracy. Evaluation of the fine-gridded soil maps demonstrated commendable results, with high consistency in summary statistics, semi-variograms, and evaluation metrics compared to reference maps. Mass preservation of RF-predicted maps exhibit high performances with both concordance correlation coefficients (CCCs) and coefficients of determination (R(2)s) exceeding 0.9 across most scenarios. This study provides a robust approach for enhancing the spatial resolution of soil maps, facilitating their use in local fine-scale applications. The proposed strategy offers a valuable solution for broad-scale areas that require finer soil maps but lack sufficient qualified soil profiles.

关键词： Digital soil mapping Broad-scale Fine gridding Downscaling Machine learning

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Experimental and numerical investigation on the tensile behaviour of rocks using the Brazilian disc method

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JOURNAL OF APPLIED GEOPHYSICS 2025年 233卷

作者： chen, Yulong Zhang, xuwen Yuan, Honghui Zhang, Junwen China Coal Res Inst Beijing 100013 Peoples R China China Univ Min & Technol Beijing Beijing 100083 Peoples R China

Characterizing engineering properties of rock especially associated with tension is crucial for stability assessment of rock structures. This study integrates physical and numerical experiments to investigate the electromagnetic radiation (EMR) and acoustic emission (AE) responses of sandstone under Brazilian disc testing. During the Brazilian splitting process, the EMR and AE responses reflect well the cracking evolution of the disc sandstone specimen. The cracking evolution process and failure mechanism are vividly illustrated. When approaching the peak stress, massive EMR and AE activities occur abruptly. Importantly, the fractal dimension and b-value of EMR and AE switch from increase to decrease once the failure initiates. Such significant decrease in the fractal dimension and b-value of EMR and AE upon failure initiation could be applied to identify the rock failure initiation.

关键词： EMR AE Brazilian disc Cracking Fractal dimension B-value

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Bright optical eigenmode with about 1 nm3 volume

arXiv

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arXiv 2020年

作者： Li, Wancong Zhou, Qiang Zhang, Pu chen, xuwen School of Physics Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Luoyu Road 1037 Wuhan430074 China

Concentrating optical field in an eigenmode with a tiny volume is vitally important for light-matter interactions at the fundamental level and underpins new technologies. In the past decades, researchers have investigated various approaches to shrink light and so far managed to reduce the volume of optical eigenmodes, under the quantum-optical definition, down to several ten nm3. Here we report on the discovery, characterization and engineering of a class of extremely localized eigenmodes that are resonances of atomistic protrusions on a metallic host nanoparticle and feature quantum-optical mode volumes of below 1 nm3. We theoretically demonstrate that these extremely localized modes can be made bright with radiation efficiencies reaching 30% and provide up to 4×107 times intensity enhancement. The existence of bright eigenmodes with the volume comparable to a photon emitter foresees exciting new optical physics, such as ultrastrong coupling with single optical emitters, angstrom-resolution optical imaging, and atomic-scale single-molecule photochemistry. Copyright © 2020, The Authors. All rights reserved.

关键词： Atomic physics

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Concise synthesis of 3,4-dihydro-1,4-benzoxazines by three-component reactions of acyl chlorides, o-aminophenols and 1,2-dichloroethane

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TETRAHEDRON 2018年第27期74卷 3691-3696页

作者： Liu, Yunyun chen, xuwen Jiangxi Normal Univ Coll Chem & Chem Engn Nanchang 330022 Jiangxi Peoples R China

The Cu(OAc)(2)-catalyzed three-component reactions of o-aminophenols, acyl chlorides and 1,2-dichloroethane (DCE) have been established for the efficient synthesis of 3,4-dihydro-2H-benzo[b][1,4] oxazines (3,4-dihydro-1,4-benzoxazines). This method features advantages of the one-pot operation enabling N-acylation, C-Cl bond amidation and etherification, as well as the structural divergence of the synthesized products. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Three-component Copper catalysis Selective 3,4-Dihydro-1,4-benzoxazine o-Chloroalkoxyl N-Acyl aniline

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Vanadium oxide activates persulfate for degradation of polycyclic aromatic hydrocarbons in aqueous system

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CHEMICAL ENGINEERING JOURNAL 2019年 364卷 79-88页

作者： chen, xuwen Yang, Bing Oleszczuk, Patryk Gao, Yanzheng Yuan, Xinjie Ling, Wanting Waigi, Michael Gatheru Nanjing Agr Univ Coll Resources & Environm Sci Inst Organ Contaminant Control & Soil Remediat Nanjing 210095 Jiangsu Peoples R China Univ Maria Sklodowska Curie Dept Environm Chem PL-20031 Lublin Poland

A novel investigation into the utilization of vanadium oxide (V2O3) as a persulfate (PS) activator in phenanthrene degradation in an aqueous system, and its subsequent pathway, was undertaken. The V2O3/PS has a high thermal degradation activity for phenanthrene at either room temperature (25 degrees C) or higher (35 degrees C and 45 degrees C), with a better performance (up to five times reuse) and a shorter degradation time. Phenanthrene can be effectively degraded under different pH conditions (pH 3, 5, 7, and 9), with a low PS concentration (2 mmol/L), activated by a small V2O3 loading (0.1 g/L). The electron paramagnetic resonance (EPR) technique combined with 5,5-dimethyl-1-pyrroline N-oxide (DMPO, 0.1 mol/L), captured sulfate (SO4 center dot-) and hydroxyl ((OH)-O-center dot) radical signals in the V2O3/PS system, generated from PS activation with V2O3. Free radical quenching studies revealed that both SO4 center dot- and (OH)-O-center dot contributed to phenanthrene degradation. The PS activation mechanism by V2O3 was elucidated. V2O3-activated PS produced SO4 center dot- and VO2 via electron transfer, with VO2 transferring a further electron to activate PS for SO4 center dot- and V2O5 generation, and a portion of the produced SO4 center dot- converted to (OH)-O-center dot. V2O3-activated PS generated four ion oxidation products (VO2, V2O5, V (V) and V (IV)), whereby VO2 and V2O5 actively participated in phenanthrene degradation, whereas V (V) and V (IV) provided no effective activation. A phenanthrene degradation pathway in the V2O3/PS system was proposed based on the identification of phenanthrene intermediates through liquid chromatography-mass spectrometry. These findings provide valuable insight into PS activation using a unique activator (V2O3) in the removal of environmental organic pollutants.

关键词： Vanadium oxide Persulfate Activator Polycyclic aromatic hydrocarbons Oxidation degradation

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Efficient Moiré pattern removal with lightweight multi-scale feature extraction

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JOURNAL OF ELECTRONIC IMAGING 2024年第2期33卷 023050-023050页

作者： Li, xuwen Gan, Min Su, JianNan chen, GuangYong Fuzhou Univ Coll Comp & Data Sci Fuzhou Peoples R China

In recent years, convolutional neural networks have excelled in image Moir & eacute;pattern removal, yet their high memory consumption poses challenges for resource-constrained devices. To address this, we propose the lightweight multi-scale network (LMSNet). Designing lightweight multi-scale feature extraction blocks and efficient adaptive channel fusion modules, we extend the receptive field of feature extraction and introduce lightweight convolutional decomposition. LMSNet achieves a balance between parameter numbers and reconstruction performance. Extensive experiments demonstrate that our LMSNet, with 0.77 million parameters, achieves Moir & eacute;pattern removal performance comparable to full high definition demoir & eacute;ing network (FHDe(2)Net) with 13.57 million parameters.

关键词： image demoir & eacute ing lightweight network information multi-distillation image restoration multi-scale feature extraction and fusion

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Geological Background Prototype Learning-Enhanced Network for Remote-Sensing-Based Engineering Geological Lithology Interpretation in Highly Vegetated Areas

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IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING 2024年 17卷 8794-8809页

作者： Ouyang, Shubing chen, Weitao Qin, xuwen Yang, Jinzhong China Univ Geosci Sch Comp Sci Wuhan 430074 Peoples R China China Geol Survey China Aero Geophys Survey & Remote Sensing Ctr Nat Beijing 100083 Peoples R China China Univ Geosci Key Lab Geol Survey & Evaluat Minist Educ Wuhan 430074 Peoples R China

Remote-sensing-based interpretation of engineering geological lithology units provides essential lithological information for engineering planning, design, and construction projects. However, dense vegetation cover can easily interfere with the lithological spectral characteristics of optical remote sensing. Utilizing known geological background prototype-guided knowledge as a guide can mitigate interpretation interference from vegetation. Hence, for the interpretation of engineering geological lithology units, we aimed to develop a novel semantic segmentation network, LSBPnet, which combines a geological background prototype-guided learning model with a U-Net-based model. The geological background prototype-guided learning model employs lithological prototype features learned from the surrounding geological units of the predicted target to identify similarities with the predicted target's features. The model encompasses three steps: inputting known background images and known labels, learning prototype features of the background information, and learning target features based on the background information prototype perception. Using the engineering geological lithology of the Yangtze River's middle reaches as the focus area, which is a region with high vegetation cover, the proposed network achieved a 13.94% increase in the overall accuracy compared with that of commonly prevalent semantic segmentation networks. Incorporating the geological background prototype-guided knowledge helped to strengthen the distinction and relationship between the target and its surrounding lithological features, thereby improving the assessment of prediction outcomes. The diverse ablation experiments further highlighted the importance of incorporating background prototype-guided knowledge.

关键词： Geology Rocks Vegetation mapping Feature extraction Remote sensing Surveys Soft sensors Deep learning engineering geological lithology units prototype learning remote sensing semantic segmentation

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Microwave-Assisted Decarbonylative Coupling Reaction of o-Halobenzamides for Phenanthridinone Synthesis

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CHEMISTRYSELECT 2018年第27期3卷 7763-7765页

作者： chen, xuwen Liu, Yunyun Jiangxi Normal Univ Coll Chem & Chem Engn Nanchang 330022 Jiangxi Peoples R China

The microwave assisted synthesis of valuable phenanthridinones via the homo-annulation of o-halobenzamides is realized via palladium catalysis. The formation of the products involves in the reductive coupling of aromatic C-X (X=Br, I) bond and the decarbonylative coupling of amide. With this method, a broad array of free NH and N-substituted phenanthridinones have been rapidly synthesized.

关键词： decarbonylative coupling microwave phenanthridinone reductive coupling tandem

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On regime changes in text data using hidden Markov model of contaminated vMF distribution

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DATA MINING AND KNOWLEDGE DISCOVERY 2024年第6期38卷 3563-3589页

作者： Zhang, Yingying Sarkar, Shuchismita chen, Yuanyuan Zhu, xuwen Western Michigan Univ Kalamazoo MI 49008 USA Bowling Green Univ Bowling Green OH 43402 USA Univ Alabama Tuscaloosa AL 35487 USA

This paper presents a novel methodology for analyzing temporal directional data with scatter and heavy tails. A hidden Markov model with contaminated von Mises-Fisher emission distribution is developed. The model is implemented using forward and backward selection approach that provides additional flexibility for contaminated as well as non-contaminated data. The utility of the method for finding homogeneous time blocks (regimes) is demonstrated on several experimental settings and two real-life text data sets containing presidential addresses and corporate financial statements respectively.

关键词： Finite mixture model Model-based clustering Hidden Markov model Von-Mises Fisher distribution Regime change EM algorithm

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