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Detection of Nonlinear Behavior Induced by Hard Limiting in Voltage Source Converters in Wind Farms Based on Higher-order Spectral Analysis

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 630-645页

作者： Zetian Zheng shaowei Huang Qiangsheng bu Chen Shen Jun Yan State Key Laboratory of Power Systems Department of Electrical EngineeringTsinghua UniversityBeijing 100084China State Grid Jiangsu Electric Power Co. Ltd.Research InstituteNanjingChina

In recent years, sub-synchronous oscillation accidents caused by wind power integration have received extensive attention. The recorded constant-amplitude waveforms can be induced by either linear or nonlinear oscillation mechanisms. Hence, the nonlinear behavior needs to be distinguished prior to choosing the analysis method. Since the 1960s, the higher-order statistics(HOS) theory has become a powerful tool for the detection of nonlinear behavior(DNB) in production quality control wherein it has mainly been applied to mechanical condition monitoring and fault diagnosis. This study focuses on the hard limiters of the voltage source converter(VSC) control systems in the wind farms and attempts to detect the nonlinear behavior caused by bi-or uni-lateral saturation hard limiting using the HOS analysis. First, the conventional describing function is extended to obtain the detailed frequency domain information on the bi-and uni-lateral saturation hard limiting. Furthermore, the bi-and tri-spectra are introduced as the HOS, which are extended into bi-and tri-coherence spectra to eliminate the effects of the linear parts on the harmonic characteristics of hard limiting in the VSC control system, respectively. The effectiveness of the HOS in the DNB and the classification of the hard-limiting types is proven, and its detailed derivation and estimation procedure is presented. Finally, the quadratic and cubic phase coupling in the signals is illustrated, and the performance of the proposed method is evaluated and discussed.

关键词： Bi-coherence spectrum detection of nonlinear behavior hard limiting higher-order statistics tri-coherence spectrum voltage source converter wind farms.

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Sponge as Scaffolds in Bone and Cartilage Tissue Engineering

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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES 2024年第5期40卷 786-797页

作者： Luo, Lei Gong, Yining Yan, Liang bu, Yazhong Yanan Univ Yanan 716000 Peoples R China Xi An Jiao Tong Univ Honghui Hosp Dept Spine Surg Xian 710054 Peoples R China Xi An Jiao Tong Univ Inst Med Engn Hlth Sci Ctr Sch Basic Med SciDept Biophys Xian 710061 Peoples R China

In recent years, tissue scaffolds have emerged as a new therapeutic method for bone and cartilage regeneration, with sponge scaffolds gaining increasing attention. Sponge scaffolds possess several favorable characteristics, including appropriate biodegradability, excellent biocompatibility, good processability, powerful osteogenic ability, a unique porous structure, and adjustable pore size and connectivity. These attributes make sponge scaffolds a promising option for bone and cartilage regeneration. However, to date, there is a lack of comprehensive reviews summarizing the use of sponge scaffolds in this field. In this review, our objective is to provide a comprehensive overview of the research progress and development trends of sponge scaffolds. Firstly, we introduce the various materials used for sponge scaffolds. Secondly, we summarize the different preparation methods employed for creating sponge scaffolds. Subsequently, we discuss the functional additives that can be incorporated into the scaffolds. Finally, we present some special structures that can be achieved in sponge scaffolds. Our aim is for this review to offer valuable insights and serve as a comprehensive resource for the design of sponge scaffolds in cartilage and bone regeneration.

关键词： Bone Sponge Scaffold Tissue regeneration COMPOSITE SCAFFOLDS REGENERATIVE MEDICINE STEM-CELLS FABRICATION IRISIN VIVO DIFFERENTIATION PHYSIOLOGY STRATEGIES MENISCUS

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Efficient reduction and adsorption of Cr(Ⅵ)using FeCl_(3)-modified biochar:Synergistic roles of persistent free radicals and Fe(Ⅱ)

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Journal of Environmental Sciences 2024年第3期137卷 626-638页

作者： Shujie Hu Chengshuai Liu Hongling bu Manjia Chen Ying-heng Fei National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of ScienceGuiyang 550081China School of Environment Science and Engineering Guangzhou UniversityGuangzhou 510006China College of Resources and Environment Chongqing SchoolUniversity of Chinese Academy of SciencesChongqing 400714China School of Environmental Science and Engineering Guangdong University of TechnologyGuangzhou 510006China

Transition metal iron and persistent free radicals(PFRs)both affect the redox properties of biochar,but the electron transfer relationship between them and the coupling reduction mechanism of Cr(Ⅵ)requires further *** untangle the interplay between iron and PFRs in biochar and the infuences on redox properties,FeCl_(3)-modified rice husk biochar(FBCs)was prepared and its reduction mechanism for Cr(Ⅵ)without light was *** FBCs had higher surface positive charges,oxygen-containing functional groups,and PFRs compared with pristine rice husk biochar(BC).Phenoxyl PFRs with high electrondonating capability formed in *** pronounced electron paramagnetic resonance signals showed that the PFRs preferred to form at lower Fe(Ⅲ)*** a high concentration of Fe(Ⅲ)would be reduced to Fe(Ⅱ)and consumed the formed *** kinetics and X-ray photoelectron spectroscopy analysis indicated that the FBCs effectively enhanced the Cr(Ⅵ)removal efficiency by 1.54-8.20 fold and the Cr(Ⅵ)reduction efficiency by 1.88-9.29 fold compared to those of *** quenching and competitive reductant addition experiments revealed that the higher Cr(Ⅵ)reduction performance of FBCs was mainly attributed to the formed PFRs,which could contribute to~74.0%of Cr(Ⅵ)reduction by direct or indirect electron *** PFRs on FBCs surfaces could promote the Fe(Ⅲ)/Fe(Ⅱ)cycle through single electron transfer and synergistically accelerate~52.3%of Cr(Ⅵ)*** study provides an improved understanding of the reduction mechanism of iron-modified biochar PFRs on Cr(Ⅵ)in environments.

关键词： Biochar Iron-modification Cr(Ⅵ) Electron transfer Reduction mechanism

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An End-To-End Hyperbolic Deep Graph Convolutional Neural Network Framework

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 537-563页

作者： Yuchen Zhou Hongtao Huo Zhiwen Hou Lingbin bu Yifan Wang Jingyi Mao Xiaojun Lv Fanliang bu School of Information Network Security People’s Public Security University of ChinaBeijing100038China Institute of Computing Technology China Academy of Railway Sciences Corporation LimitedBeijing100081China

Graph Convolutional Neural Networks(GCNs)have been widely used in various fields due to their powerful capabilities in processing graph-structured ***,GCNs encounter significant challenges when applied to scale-free graphs with power-law distributions,resulting in substantial ***,most of the existing GCN models are shallow structures,which restricts their ability to capture dependencies among distant nodes and more refined high-order node features in scale-free graphs with hierarchical *** more broadly and precisely apply GCNs to real-world graphs exhibiting scale-free or hierarchical structures and utilize multi-level aggregation of GCNs for capturing high-level information in local representations,we propose the Hyperbolic Deep Graph Convolutional Neural Network(HDGCNN),an end-to-end deep graph representation learning framework that can map scale-free graphs from Euclidean space to hyperbolic *** HDGCNN,we define the fundamental operations of deep graph convolutional neural networks in hyperbolic ***,we introduce a hyperbolic feature transformation method based on identity mapping and a dense connection scheme based on a novel non-local message passing *** addition,we present a neighborhood aggregation method that combines initial structural featureswith hyperbolic attention *** the above methods,HDGCNN effectively leverages both the structural features and node features of graph data,enabling enhanced exploration of non-local structural features and more refined node features in scale-free or hierarchical *** results demonstrate that HDGCNN achieves remarkable performance improvements over state-ofthe-art GCNs in node classification and link prediction tasks,even when utilizing low-dimensional embedding ***,when compared to shallow hyperbolic graph convolutional neural network models,HDGCNN exhibits notable advantages and performance enhanceme

关键词： Graph neural networks hyperbolic graph convolutional neural networks deep graph convolutional neural networks message passing framework

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Epicatechin attenuates lead(Pb)-induced cognitive impairment in mice:regulation on Nrf2 signaling pathway,and interference on the interaction between Pb with albumin

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Food Science and Human Wellness 2024年第2期13卷 1065-1078页

作者： Dai Cheng Qianqian Yu Kexin Zhu Dingdong bu Zijian Wu State Key Laboratory of Food Nutrition and Safety Tianjin University of Science&TechnologyTianjin 300457China School of Biotechnology and Food Science Tianjin University of CommerceTianjin 300134China

Epicatechin(EC)was used in this study to antagonize the cognitive dysfunction caused by lead(Pb)exposure in ***-week-old male Kunming mice were treated with PbCl_(2)(20 mg/kg)and/or EC(50 mg/kg)by gavage administration for 4 *** water maze test showed that EC could improve memory dysfunction induced by *** antagonized Ca^(2+)overload,activated Nrf2 signaling pathway and reduced the accumulation of Pb in the brain and serum,which suggested that EC might alter Pb distribution in *** vitro,spectroscopic analysis,potentiometric titration and docking studies were applied to inquiry into the interaction between bovine serum albumin(BSA)and Pb^(2+)in presence or absence of *** was proved to chelate Pb^(2+)and reduced the interaction between BSA and Pb^(2+).In summary,EC might protect Pb-induced cognitive impairment by activating Nrf2 signaling pathway,and suppressing Pb accumulation via interference on the binding of Pb to albumin.

关键词： Lead Epicatechin Bovine serum albumin Interaction Oxidative stress

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Chiral quantum heating and cooling with an optically controlled ion

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Light(Science & Applications) 2024年第7期13卷 1393-1400页

作者： Jin-Tao bu Jian-Qi Zhang Ge-Yi Ding Jia-chong Li Jia-Wei Zhang Bin Wang Wen-Qiang Ding Wen-Fei Yuan Liang Chen Qi Zhong Ali Keçebaş Şahin KÖzdemir Fei Zhou Hui Jing Mang Feng State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsInnovation Academy of Precision Measurement Science and TechnologyChinese Academy of Sciences430071 WuhanChina. University of the Chinese Academy of Sciences 100049 BeijingChina. Research Center for Quantum Precision Measurement Guangzhou Institute of Industry Technology511458 GuangzhouChina. Department of Engineering Science and Mechanics and Materials Research InstitutePennsylvania State UniversityUniversity ParkState CollegePA 16802USA. Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal University410081 ChangshaChina. Department of Physics Zhejiang Normal University321004 JinhuaChina

Quantum heat engines and refrigerators are open quantum systems,whose dynamics can be well understood using a non-Hermitian formalism.A prominent feature of non-Hermiticity is the existence of exceptional points(EPs),which has no counterpart in closed quantum *** has been shown in classical systems that dynamical encirclement in the vicinity of an EP,whether the loop includes the EP or not,could lead to chiral mode ***,we show that this is valid also for quantum systems when dynamical encircling is performed in the vicinity of their Liouvillian EPs(LEPs),which include the effects of quantum jumps and associated noise—an important quantum feature not present in previous *** demonstrate,using a Paul-trapped ultracold ion,the first chiral quantum heating and refrigeration by dynamically encircling a closed loop in the vicinity of an *** witness the cycling direction to be associated with the chirality and heat release(absorption)of the quantum heat engine(quantum refrigerator).Our experiments have revealed that not only the adiabaticity breakdown but also the Landau–Zener–Stückelberg process play an essential role during dynamic encircling,resulting in chiral thermodynamic *** observations contribute to further understanding of chiral and topological features in non-Hermitian systems and pave a way to exploring the relation between chirality and quantum thermodynamics.

关键词： quantum chiral dynamical

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Enhancement and Removal of PM_(2.5)by Cold and Warm Air Masses Accompanying Certain Synoptic Weather Systems across Hangzhou,China during 2014-2020

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Journal of Meteorological Research 2024年第3期38卷 620-634页

作者： bu YU Feng CHEN Hanqing KANG Bin ZHU Hongnian LIU Hangzhou Meteorological bureau Hangzhou310051China Hangzhou International Urbanology Research Center for Urban Governance Studies Hangzhou311121China Zhejiang Institute of Meteorological Sciences Hangzhou310008China Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science&TechnologyNanjing210044China School of Atmospheric Sciences Nanjing UniversityNanjing210023China

Local air pollution is strongly affected by synoptic weather systems,such as fronts,troughs,low-altitude vortices,or high-altitude ***,few studies have analyzed the meteorological properties of cold or warm air masses associated to these systems and their impact on local air *** this study,hourly observations of fine particulate matter(diameter of up to 2.5µm,i.e.,PM_(2.5)),wind(V),temperature(T),pressure(P),and precipitation(R),acquired in Hangzhou in 2014-2020,were *** this analysis,weather patterns were categorized into 27 types;89 and 94 cases illustrating the passage of warm and cold air masses over Hangzhou were identified,respectively;the influence of air mass temperature,wind speed,and wind direction on PM_(2.5) concentrations and local accumulation or removal was *** main results are as follows.(1)Pollution events occurred more frequently for cold than for warm air masses,but average pollutant concentration was lower for cold air masses;(2)48%of the cold air mass cases corresponded to PM_(2.5) decreases and 52%to PM_(2.5) increases,with strong cold air masses(ΔT_(24h)>4°C;∣V∣_(average)>4 m s^(−1))markedly reducing local pollution,but weak cold air masses(ΔT24h4°C)reduced the PM_(2.5) concentration whereas weaker winds(∣V∣_(average)but more gradually within 14 h after the passage of strong warm air *** results considerably improve the current understanding of the influence of cold and warm air masses on local pollution patterns.

关键词： weather type air mass enhancement removal meteorological condition

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NCAD v1.0: a database for non-coding variant annotation and interpretation

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Journal of Genetics and Genomics 2024年第2期51卷 230-242页

作者： Xiaoshu Feng Sihan Liu Ke Li Fengxiao bu Huijun Yuan Institute of Rare Diseases West China HospitalSichuan UniversityChengduSichuan 610044China

The application of whole genome sequencing is expanding in clinical diagnostics across various genetic disorders, and the significance of non-coding variants in penetrant diseases is increasingly being demonstrated. Therefore, it is urgent to improve the diagnostic yield by exploring the pathogenic mechanisms of variants in non-coding regions. However, the interpretation of non-coding variants remains a significant challenge, due to the complex functional regulatory mechanisms of non-coding regions and the current limitations of available databases and tools. Hence, we develop the non-coding variant annotation database (NCAD, http://***/), encompassing comprehensive insights into 665,679,194 variants, regulatory elements, and element interaction details. Integrating data from 96 sources, spanning both GRCh37 and GRCh38 versions, NCAD v1.0 provides vital information to support the genetic diagnosis of non-coding variants, including allele frequencies of 12 diverse populations, with a particular focus on the population frequency information for 230,235,698 variants in 20,964 Chinese individuals. Moreover, it offers prediction scores for variant functionality, five categories of regulatory elements, and four types of non-coding RNAs. With its rich data and comprehensive coverage, NCAD serves as a valuable platform, empowering researchers and clinicians with profound insights into non-coding regulatory mechanisms while facilitating the interpretation of non-coding variants.

关键词： Non-coding variants Annotation Variant interpretation Database

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Optimization of Generator Based on Gaussian Process Regression Model with Conditional Likelihood Lower Bound Search

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 32-42页

作者： Xiao Liu Pingting Lin Fan bu shaoling Zhuang Shoudao Huang CES&IEEE the College of Electrical and Information Engineering Hunan UniversityChangsha 410082China CES

The noise that comes from finite element simulation often causes the model to fall into the local optimal solution and over fitting during optimization of ***,this paper proposes a Gaussian Process Regression(GPR)model based on Conditional Likelihood Lower Bound Search(CLLBS)to optimize the design of the generator,which can filter the noise in the data and search for global optimization by combining the Conditional Likelihood Lower Bound Search *** the efficiency optimization of 15 kW Permanent Magnet Synchronous Motor as an ***,this method uses the elementary effect analysis to choose the sensitive variables,combining the evolutionary algorithm to design the super Latin cube sampling plan;Then the generator-converter system is simulated by establishing a co-simulation platform to obtain data.A Gaussian process regression model combing the method of the conditional likelihood lower bound search is established,which combined the chi-square test to optimize the accuracy of the model ***,after the model reaches the accuracy,the Pareto frontier is obtained through the NSGA-II algorithm by considering the maximum output torque as a ***,the constrained optimization is transformed into an unconstrained optimizing problem by introducing maximum constrained improvement expectation(CEI)optimization method based on the re-interpolation model,which cross-validated the optimization results of the Gaussian process regression *** above method increase the efficiency of generator by 0.76%and 0.5%respectively;And this method can be used for rapid modeling and multi-objective optimization of generator systems.

关键词： Generator optimization Gaussian Process Regression(GPR) Conditional Likelihood Lower Bound Search(CLLBS) Constraint improvement expectation(CEI) Finite element calculation

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Surface iodine and pyrenyl-graphdiyne co-modified Bi catalysts for highly efficient CO_(2) electroreduction in acidic electrolyte

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Nano Research 2024年第4期17卷 2381-2387页

作者： Min Zhang Juan Wang Xin Rong Xiu-Li Lu Tong-bu Lu MOE International Joint Laboratory of Materials Microstructure Institute for New Energy Materials and Low Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China

CO_(2) electroreduction to formic acid/formate would contribute to alleviating the energy and climate *** work reports a Bi-based catalyst derived from the in-situ electroreduction of Bi_(2)O_(2)CO_(3) modified with iodine and pyrenyl-graphdiyne(PGDY)on the surface for efficient electroreduction of CO_(2) in acidic electrolyte,with a high partial current density of 98.71 mA·cm^(-2) and high Faradaic efficiency(FE)>90%over the potential range from^(-1).2 to-1.5 V *** hydrogen electrode(RHE),as well as the long-term operational stability over 240 h without degradation in H-type *** results and density function theory calculations show that the synergistic effect of surface iodine and PGDY is responsible for this active and extremely stable process of CO_(2) electroreduction via lowering the energy barriers for formation of*OCHO intermediate,suppressing the competitive HER by enhancing the concentration of both K+and CO_(2) at reaction interface,as well as preventing the dissolution and re-deposition of active Bi atoms on surface during catalytic *** work provides new insight into designing highly active and stable electrocatalysts for CO_(2) reduction.

关键词： CO_(2) reduction electrocatalysis Bi-based catalysts acidic electrolyte

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