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Acidic oxygen evolution reaction:Mechanism,catalyst classification,and enhancement strategies

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Interdisciplinary materials 2023年第1期2卷 53-90页

作者： qianli ma Shichun Mu Fuel cell materials Laboratory Foshan Xianhu LaboratoryFoshanChina State Key Laboratory of Advanced Technology for materials Synthesis and Processing Wuhan University of TechnologyWuhanChina

As the most desirable hydrogen production device,the highly efficient acidic proton exchange membrane water electrolyzers(PEMWE)are severely limited by the sluggish kinetics of oxygen evolution reaction(OER)at the *** IrO2 is a commercial acid-stable OER catalyst with poor activity and high cost,which has motivated the development of ***,hitherto most of the designed acidic OER catalysts have disadvantages of low activity or stability,which cannot meet the requirement of industrial ***,exploring suitable strategies to enhance the activity and stability of cost-effective acidic OER catalysts is crucial for developing the PEMWE *** this review,the main OER mechanisms,different types of catalysts,and their activity and stability characteristics are summarized and discussed,and then possible strategies to improve activity and stability are ***,the problems and prospects of such catalysts are generalized to shed some light on the future research of advanced catalysts for acidic OER.

关键词： catalyst hydrogen energy oxygen evolution reaction proton exchange membrane water electrolyzer water oxidation

Dynamic soil arching in piled embankment under train load of high-speed railways

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 719-730页

作者： Niu Tingting Yang Yule ma qianli Zou Jiuqun Lin Bin School of Civil Engineering and Architecture Anhui University of Science and TechnologyHuainan 232001China College of Civil and Transportation Engineering Hohai UniversityNanjing 210098China

Piled embankments have many advantages that have been applied in high-speed railway construction ***,the load transfer mechanism of piled embankments,such as soil arching and tension membranes,is still unclear,especially under dynamic *** investigate the soil arching and tension membrane under dynamic train loads on high-speed railways,a large-scale piled embankment model test with X-shaped piles as vertical reinforcement was performed,in which twenty-eight earth pressure cells were installed in the piled embankment and an M-shaped wave was adopted to simulate the high-speed railway train *** results show that dynamic soil arching only occurs when two bogies of a carriage pass by and disappears at other *** dynamic soil arching and membrane effect are the most significant under the concrete *** arching height,stress concentration ratio and pile-soil load sharing ratio have a minimal value at 25 *** dynamic soil arching degrades severely at 25 Hz,whose height at 25 Hz is only 0.35 times that at 5 *** arching height fluctuates over a narrow range with increasing loading *** stress concentration ratio and the pile-soil load sharing ratio increase monotonically as the loading amplitude increases.

关键词： dynamic soil arching membrane effect piled embankment train load model test

A survey on ensemble learning

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Frontiers of Computer Science 2020年第2期14卷 241-258页

作者： Xibin DONG Zhiwen YU Wenming CAO Yifan SHI qianli ma School of Computer Science and Engineering South China University of TechnologyGuangzhou 510006China Department of Computer Science City University of Hong KongHong Kong SAR 999077China

Despite significant successes achieved in knowledge discovery,traditional machine learning methods may fail to obtain satisfactory performances when dealing with complex data,such as imbalanced,high-dimensional,noisy data,*** reason behind is that it is difficult for these methods to capture multiple characteristics and underlying structure of *** this context,it becomes an important topic in the data mining field that how to effectively construct an efficient knowledge discovery and mining *** learning,as one research hot spot,aims to integrate data fusion,data modeling,and data mining into a unified ***,ensemble learning firstly extracts a set of features with a variety of *** on these learned features,multiple learning algorithms are utilized to produce weak predictive ***,ensemble learning fuses the informative knowledge from the above results obtained to achieve knowledge discovery and better predictive performance via voting schemes in an adaptive *** this paper,we review the research progress of the mainstream approaches of ensemble learning and classify them based on different *** addition,we present challenges and possible research directions for each mainstream approach of ensemble learning,and we also give an extra introduction for the combination of ensemble learning with other machine learning hot spots such as deep learning,reinforcement learning,etc.

关键词： ensemble learning supervised ensemble classification semi-supervised ensemble classification clustering ensemble semi-supervised clustering ensemble

Characteristics of Particulate matter Emissions for Low-Sulfur Heavy Oil Used in Low-Speed Two-Stroke Diesel Engines of Ocean-Going Ships

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Journal of Thermal Science 2024年第2期33卷 739-750页

作者： WU Gang ma qianli WEI Lijiang JIANG Guohe WANG Tengfei LI Tie Merchant marine College Shanghai Maritime UniversityShanghai201306China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai200240China

In this work,particulate matter(PM) emissions from a large two-stroke,low-speed marine diesel engine were investigated when the engine was operated with low-sulfur heavy fuel oil(HFO) at various *** samples were collected in situ from the engine exhaust to determine the detailed physical and chemical *** nanostructure and morphology of the nanoparticles were analyzed using transmission electron microscopy images(TEM).The results show that volatile organic carbon(OC) accounts for more than 80% in the HFO particles and leads to an increase in particle *** thermodynamic conditions of a low-speed engine favor the behavior of capturing the soluble organic components.A large number of spherical char HFO particles with aerodynamic diameters of 0.2 μm-0.5 μm and a suspected inner metal core were *** two peak aerodynamic diameters of the HFO nanoparticles are 15 nm and 86 *** morphological differences among the HFO nanoparticles in varied engine conditions represent the formation process from primary nascent particles to mature graphitized particles caused by *** above study will be valuable for understanding the characteristics of PM emissions from low-sulfur HFO to achieve the ship PM emissions reduction target.

关键词： low-speed diesel engine maritime regulations heavy fuel oil TEM particles size and distribution

The Key Technology on Chinese Word Segmentation Based on Bi-LSTM-CRF Model

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The Key Technology on Chinese Word Segmentation Based on Bi-...

作者： qianli ma 华中师范大学

学位级别：硕士

自然语言处理是人工智能领域的核心技术之一,而自然语言处理中的汉语分词是自然语言处理的基础。目前主流的分词方法是基于传统的机器学习模型。近年来,随着人工智能浪潮的再次兴起,无论是短期记忆还是长期记忆的LSTM神经网络模型都对... 详细信息

自然语言处理是人工智能领域的核心技术之一,而自然语言处理中的汉语分词是自然语言处理的基础。目前主流的分词方法是基于传统的机器学习模型。近年来,随着人工智能浪潮的再次兴起,无论是短期记忆还是长期记忆的LSTM神经网络模型都对传统的循环神经网络模型进行了改进,该模型能长期依赖于信息的不足,并广泛应用于自然语言处理各种任务,取得了良好的效果。作为自然语言处理模块的重要组成部分,中文分词的好坏会影响到基于自然语言处理的相关研究,中文分词盼段将会影响相关的精度,因此中文分词阶段的精度将会其他例如语义和语法层次以及应用层次,分词的精度是衡量这一阶段的重要指标。在中文分词的精度提升上,必须解决如下几个关键问题:1.在中文分词中3如何拥有更高的识别精度是该自然语言处理子方向的首要解决的问题。不仅仅通过该词在句子中的位置来预測分词结果往往是不够的,而对上下文进行依赖,通过句子位置和上下文之间的关系进行分词更加的具有研究价值和重要意义。2.传统的神经模型LSTM模型已经证明在处理信息学习有着相当大的优势,但是LSTM神经网络的前向传导的特点,在训练过程中会导致部分后文的关系并没有被考虑学习,解决全文的上下文关系的学习,防止文本依赖不足所导致的问题也是需要研究的方向。3.对于根据上下文之间的潜在关系进行研究所得出来的结果是基于非规则的研究,但这些上下文关系有的时候并不以一定具有普遍的确定性,这样会导致尽管上下文有联系但是会出现一些前词和后词逻辑性并没有关联的结果,如何增加中文分词的逻辑性对提升中文分词精度有相当的理论研究价值。4.对每一个通过神经网络进行模型都有者自己最佳的参数学习方式,以此来达到局部最优解,对模型相关的参数需要通过不断调整来达到较优以接近最优值。通过上述对问题的阐述,本文在解决上述问题的主要贡献是（1）首先对经典的单向LSTM模型进行了改进,通过增加正向LSTM层并设针双向LSTM模型。这样通过对文本进行前向和后向的传导,以此来改善单向LSTM对以下文本的依赖不足。（2）在神经网络通过添加CRF层,增加了单词间的约束。通过使用CRF所具有的转移矩阵特性来学习单词之间的逻辑,提高因逻辑错误所导致的分词结果精度降低。（3）通过验证词向量嵌入的必要性和设置最佳Dropout防止过拟合,以及动态调整学习率等参数设置来达到模型最佳的精度。在整体的设计上,首先在传统神经网络的基础上,对增加的字向量进行改进,利用字嵌入预处理,然后扩展到LSTM层的双向LSTM,并通过整个连接增加了CRF层的密集度。本文利用Bakeoff提供的SIGAN2006会议进行了主要对比实验。通过实验,基于本文的BI-LSTM-CRF模型取得了较好的效果。通过北京大学的数据集PKU和微软的数据集MSA，准确率和查全率都达到了很好的效果。在机器学习方面,条件随机场可以达到很好的分词效果,在深度学习方面,分词效果得到了更明显的提高。本文主要通过结合双向记忆相关神经网络模型的优化,原LSTM单元结构的神经网络每时每刻、每一步都在执行一种记忆机制,但每一个计算量随着句子长度的增加而激增,导致分词阶段的任务效果较差,逻辑问题较多。本文的改进是词向量用于维度预处理,然后双向段记忆神经深度学习神经网络模型是用来进行隐藏的多个循环传输层,从而达到最好的中文分词的效果。该方法较好地解决了单隐层、防止过拟合以及卷积神经网络不能处理长依赖序列信息的缺点。同时,双向短记忆和长记忆依赖神经网络解决了简单循环神经网络长期依赖和单向LSTM无法利用方向序列信息的问题。经过softmax和dense层处理后,输出将是每个单词所携带的标签的概率。为了解决一些单词没有逻辑的问题,将输出放入CRF层进行传输矩阵处理。最后,合并后的BI-LSTM-CRF模型可以更好地从语义角度进行分词。在最终的实验中,在预实验中人民日报1998语料库的数据集P值为95.3359%,R值为95.1864%,F1值为95.3359%。人民日报2014语料库的数据集P值为96.7524%,R值为94.7981%,F1值为95.7653%。国家数据集P值为93.1640%,R值为93.2534%,F1值为93.2087%。在最终对比实验数据中,在微软的MSRA数据集,通过F1值的比较,通过F1值的比较,可以看出bi-lstm-crf模型的F1值约为2.9%高于CRF++模型,和高于LSTM模型0.9%,bilstm模型高出0.8%,高于Istm-crf模型0.8%。从p值和r值可以看出,基于MSRA数据集的bi-lstm-crf模型比其他模型工作得更好。在PKU数据集中,在P值比较中,bi-lstm-CRF模型比LSTM-CRF模型低0.2%,但比CRF++模型高0.7%左右,比LSTM模型高0.4%左右,比bilstm模型高0.4

关键词： BI-LSTM-CRF模型中文分词机器学习神经网络条件随机场

Eu^(3+)ions grafted polyacrylonitrile nanofibers possessing enhanced fluorescence performance by introducing benzoic acid as assistant ligand

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Journal of Rare Earths 2022年第3期40卷 421-427,I0003页

作者： Ping Wu qianli ma Wensheng Yu Jinxian Wang Guixia Liu Xiangting Dong Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province Changchun University of Science and TechnologyChangchun 130022China

Eu^(3+) ions were grafted onto the surface of electrospun polyacrylonitrile(PAN)nanofibers through coordination effect between C≡N groups on PAN nanofibers and Eu^(3+) ions,and benzoic acid(BA)was introduced as an assistant *** impacts of concentrations of Eu^(3+) ions and BA,and reaction time on the properties of final products were *** results reveal that Eu^(3+) ions can be successfully grafted onto PAN nanofibers,but the fluorescence intensity of the obtained PAN@Eu^(3+) nanofibers is very *** BA is introduced as the assistant ligand,the fluorescence intensity of the obtained PAN@(Eu^(3+)/BA)nanofibers is greatly stronger than that of PAN@Eu^(3+)nanofibers,and meanwhile,concentration quenching effect of Eu^(3+) ions can be effectively ***,the superior structure of PAN@(Eu^(3+)/BA)nanofibers not only brings the effective utilization of precious elemental europium,but also guarantees high mechanical strength.

关键词： Electrospinning Polyacrylonitrile Nanofibers Fluorescence Rare earths

Significant downward trend of SO_2 observed from 2005 to 2010 at a background station in the Yangtze Delta region,China

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Science China Chemistry 2012年第7期55卷 1451-1458页

作者： QI HuangXiong LIN WeiLi XU XiaoBin YU XiangMing ma qianli Institute of Urban Planning and Environmental management Zhejiang University of Finance and EconomicsHangzhou 310012China Key Laboratory for Atmospheric Chemistry Chinese Academy of Meteorological SciencesBeijing 100081China Center for Atmosphere Watch and Services Meteorological Observation CentreChina Meteorological AdministrationBeijing 100081China Linan Regional Atmosphere Background Station Linan 311307China

SO2 is an important gas in atmosphere with great environmental and climate ***2 emission in China has been receiving great attention as the economy grows and the amount of coal consumption has increased in the past few ***2 has been observed from July 2005 to June 2010 at Linan WMO GAW regional station(30.3 °N,119.73 °E,138 m a.s.l.) located in the Yangtze Delta region in eastern *** observation data are analyzed to understand the trend of regional SO2 background *** quality controls are conducted to ensure the temporal comparability of the *** downward trend with ?2.4 ppb/yr(P < 0.0001) of surface SO2 is observed from 2005 to 2010,especially after *** average concentration of SO2 from July 2005 to June 2008 is 14.2±3.1 ppb,which is slightly higher than the mean values of 13.5±5.1 ppb during 1999?2000 and is two folds of the average value(7.1±3.1 ppb) from July 2008 to June *** than 50% of the SO2 has been cut down after 2008 in the Yangtze Delta region due to the implementation of stricter emission control *** peak SO2 concentration appears around 10 o'clock in the morning after 2009 while appears at night before *** diurnal variations of SO2 might indicate that after 2009,more SO2 is from the vertical exchange process than from the local accumulation.

关键词： SO2 background level trend Yangtz Delta Region

Dramatic decline of observed atmospheric CO_(2) and CH_(4) during the COVID-19 lockdown over the Yangtze River Delta of China

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Journal of Environmental Sciences 2023年第2期124卷 712-722页

作者： Miao Liang Yong Zhang qianli ma Dajiang Yu Xiaojian Chen Jason Blake Cohen Meteorological Observation Center China Meteorological AdministrationBeijing 100081China Lin’an Atmospheric Regional Background Station China Meteorological Administration(CMA)Hangzhou 311307China Longfengshan Regional Background Station China Meteorological Administration(CMA)Heilongjiang 150200China Shanxi Meteorological Information Center China Meteorological Administration(CMA)Shanxi 030000China School of Environment and Spatial Informatics China University of Mining and TechnologyXuzhou221116China

The temporal variation of greenhouse gas concentrations in China during the COVID-19 lockdown in China is analyzed in this work using high resolution measurements of near surface ΔCO_(2),ΔCH_(4) andΔCO concentrations above the background conditions at Lin’an station(LAN),a regional background station in the Yangtze River Delta *** the pre-lockdown observational period(IOP-1),bothΔCO_(2) andΔCH_(4) exhibited a significant increasing trend relative to the 2011-2019 climatological *** reduction ofΔCO_(2),ΔCH_(4) andΔCO during the lockdown observational period(IOP-2)(which also coincided with the Chinese New Year Holiday)reached up to 15.0 ppm,14.2 ppb and 146.8 ppb,respectively,and a reduction ofΔCO_(2)/ΔCO probably due to a dramatic reduction from industrial emissions.ΔCO_(2),ΔCH_(4) and ΔCO were observed to keep declining during the post-lockdown easing phase(IOP-3),which is the synthetic result of lower than normal CO_(2) emissions from rural regions around LAN coupled with strong uptake of the terrestrial ***,the trend reversed to gradual increase for all species during the later easing phase(IOP-4),with ΔCO_(2)/ΔCO constantly increasing from IOP-2 to IOP-3 and finally IOP-4,consistent with recovery in industrial emissions associated with the staged resumption of economic *** average,ΔCO_(2) declined sharply throughout the days during IOP-2 but increased gradually throughout the days during *** findings showcase the significant role of emission reduction in accounting for the dramatic changes in measured atmosphericΔCO_(2) and ΔCH_(4) associated with the COVID-19 lockdown and recovery.

关键词： Atmospheric CO_(2) Atmospheric CH_(4) COVID-19 lockdown The Yangtze river delta

Diketopyrrolopyrrole-derived organic small molecular dyes for tumor phototheranostics

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Chinese Chemical Letters 2022年第4期33卷 1681-1692页

作者： qianli ma Xu Sun Weili Wang Dongliang Yang Cangjie Yang Qian Shen Jinjun Shao Key Laboratory of Flexible Electronics(KLOFE)&Institute of Advanced materials(IAM) Nanjing Tech University(NanjingTech)Nanjing 211800China Department of Chemistry Boston CollegeChestnut HillMassachusetts 02467United States

Cancer is one of the leading causes of human death around the world. Phototherapy, including photodynamic therapy(PDT) and photothermal therapy(PTT), is an emerging light-triggered cancer treatment and shows the advantages of non-invasiveness and low side effects. The design and preparation of efficient phototherapeutic agents are of great significance for phototherapy. Diketopyrrolopyrrole(DPP) is a small molecular organic dye featuring outstanding photophysical properties, facile tuning of structures and properties, and excellent photostability;thus, phototherapeutic agents based on organic small molecular DPP derivatives have attracted significant research attention for not only phototherapy but also photodiagnosis of fluorescence imaging(FLI) and photoacoustic imaging(PAI). This review summarizes the recent progress of various DPP-based organic small molecules on phototheranostics during the last five years. The molecular structure design and their phototheranostics performances are discussed in detail,as will be of great help for further creation of DPP-based phototheranostics.

关键词： Diketopyrrolopyrrole Phototherapy Photodynamic Photothermal NIR dye