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Enhanced secondary organic aerosol formation during dust episodes by photochemical reactions in the winter in Wuhan

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Journal of Environmental Sciences 2023年第11期133卷 70-82页

作者： Kai Xu Yafei Liu Chenlu Li Chen Zhang Xingang Liu Qijie Li min xiong Yujun Zhang Shijie Yin Yu Ding State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China Wuhan Municipality Environmental Monitoring Center Wuhan 430015China College of Environment and Ecology Chongqing UniversityChongqing 400030China

To investigate the effect of frequently occurring mineral dust on the formation of secondary organic aerosol(SOA),106 volatile organic compounds(VOCs),trace gas pollutants and chemical components of PM_(2.5) were measured continuously in January 2021 in Wuhan,Central China.The observation period was divided into two stages that included a haze period and a following dust period,based on the ratio of PM_(2.5) and PM_(10) concentrations.The average ratio of secondary organic carbon(SOC)to elemental carbon(EC)was 1.98 during the dust period,which was higher than that during the haze period(0.69).The contribution of SOA to PM_(2.5) also increased from 2.75% to 8.64%.The analysis of the relationships between the SOA and relative humidity(RH)and the odd oxygen(e.g.,O_(X)=O_(3)+NO_(2))levels suggested that photochemical reactions played a more important role in the enhancement of SOA production during the dust period than the aqueous-phase reactions.The heterogeneous photochemical production of OH radicals in the presence of metal oxides during the dust period was believed to be enhanced.Meanwhile,the ratios of trans-2-butene to cis-2-butene and m-/p-xylene to ethylbenzene(X/E)dropped significantly,confirming that stronger photochemical reactions occurred and SOA precursors formed efficiently.These results verified the laboratory findings that metal oxides in mineral dust could catalyse the oxidation of VOCs and induce higher SOA production.

关键词： VOCs mineral dust Metal oxides SOA Photochemical reactions

Pyrolysis behaviour and combustion kinetics of waste printed circuit boards

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International Journal of minerals,Metallurgy and Materials 2022年第9期29卷 1722-1732页

作者： Kang Yan Chongwei Liu Liping Liu min xiong Jiongtong Chen Zhongtang Zhang Shuiping Zhong Zhifeng Xu Jindi Huang School of Metallurgy Engineering Jiangxi University of Science and TechnologyGanzhou 341000China Ganzhou Engineering Technology Research Center of Green Metallurgy and Process Intensification Ganzhou 341000China Jiangxi College of Applied Technology Ganzhou 341000China Key Laboratory of Ionic Rare Earth Resources and Environment Ministry of Natural ResourcesGanzhou 341000China

The effective recycling of waste printed circuit boards(WPCBs)can conserve resources and reduce environmental pollution.This study explores the pyrolysis and combustion characteristics of WPCBs in various atmospheres through thermogravimetric and Gaussian fitting analyses.Furthermore,this study analyses the pyrolysis products and combustion processes of WPCBs through thermogravimetric and Fourier transform infrared analyses(TG-FTIR)and thermogravimetry-mass spectrometry(TG-MS).Results show that the pyrolysis and combustion processes of WPCBs do not constitute a single reaction,but rather an overlap of multiple reactions.The pyrolysis and combustion process of WPCBs is divided into multiple reactions by Gaussian peak fitting.The kinetic parameters of each reaction are obtained by the Coats-Redfern method.In an argon atmosphere,pyrolysis consists of the overlap of the preliminary pyrolysis of epoxy resin,pyrolysis of small organic molecules,and pyrolysis of brominated flame retardants.The thermal decomposition process in the O_(2) atmosphere is mainly divided into two reactions:brominated flame retardant combustion and epoxy combustion.This study provided the theoretical basis for pollution control,process optimization,and reactor design of WPCBs pyrolysis.

关键词： waste printed circuit board pyrolysis mechanism combustion Gauss peak fitting

组合两步分解和ARIMA-LSTM的短期风速预测研究

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太阳能学报 2024年第2期45卷 164-171页

作者：陈蕻峰王贺李岩熊敏北京林业大学工学院北京100083 南方电网能源发展研究院有限责任公司广州510623 美国田纳西大学电气与计算机科学系诺克斯韦尔37996

为提高风速序列预测精度,提出一种基于两步分解的短期风速组合预测模型,首先使用鲁棒经验模态分解(REMD)将风速数据分解为不同频率的子序列,然后将REMD分解得到的高频模态分量使用小波包分解(WPD)进行第二步分解,降低风速序列不稳定性,... 详细信息

为提高风速序列预测精度,提出一种基于两步分解的短期风速组合预测模型,首先使用鲁棒经验模态分解(REMD)将风速数据分解为不同频率的子序列,然后将REMD分解得到的高频模态分量使用小波包分解(WPD)进行第二步分解,降低风速序列不稳定性,提高其可预测性。其次对分解得到的高频子序列建立长短期记忆神经网络(LSTM)预测模型,低频子序列建立差分自回归移动平均模型(ARIMA)预测模型。最后叠加子序列预测结果得到风速预测结果。通过两组不同风速数据集的实验对该模型的性能进行科学评估,模型预测结果的平均绝对误差分别为0.3026、0.1255;均方根误差分别为0.498、0.1607。与其他几种对比预测模型相比,验证该模型具有一定的优越性。

关键词：风速神经网络统计方法两步分解鲁棒经验模态分解组合预测

Layout Design of Conductive Heat Channel by Emulating Natural Branch Systems

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Journal of Bionic Engineering 2018年第3期15卷 567-578页

作者： Yidong Ji Xiaohong Ding Hao Li min xiong School of Mechanical engineering University of Shanghai for Science and Technology Shanghai 200093 China

To design effective and easy-to-manufacture conductive heat channels, a heuristic method by emulating the natural branch systems is suggested. The design process of the method is divided into two steps, which are the principal channel design and the lateral channel design. During the process, the width of each channel is controlled by the bifurcation law, and the end point of the channel is located at the point with the maximum temperature while the start points of the principal channel and the lateral channel are respectively determined by the location of the heat sink and the law of the minimum thermal resistance. Four design examples with different boundary conditions are studied by the suggested method, and the design results are compared with that of the traditional structural topology optimization method. Not only lower maximum temperature and relatively uniform distribution of temperature are obtained by the suggested method, but also straight channels are achieved without gray element, which is easy to manufacture. The suggested method inspired by the natural branch systems can provide an effective solution for heat channel design in the heat dissipation structures.

关键词： conductive heat channel bionic layout design natural branch system thermal resistance bifurcation law

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新媒体背景下高校志愿服务实践育人策略探究

兰州职业技术学院学报 2024年第1期40卷 29-31页

作者：熊敏泉州幼儿师范高等专科学校福建泉州362000

在高校第二课堂体系中,志愿服务是一个非常关键的构成内容,也是高校实现育人目标的一个必要路径。新媒体技术的应用必然会对高校志愿服务工作的开展带来不容忽视的影响,使其迎来更多的机遇与挑战。结合新媒体发展趋势,从创新工作理念、... 详细信息

在高校第二课堂体系中,志愿服务是一个非常关键的构成内容,也是高校实现育人目标的一个必要路径。新媒体技术的应用必然会对高校志愿服务工作的开展带来不容忽视的影响,使其迎来更多的机遇与挑战。结合新媒体发展趋势,从创新工作理念、注重统筹指导、创建并完善管理体系、营造浓厚氛围等方面探讨高校志愿服务实践育人策略,以确保高校志愿服务工作高质量推进。

关键词：新媒体高校志愿服务实践育人

Impacts of reducing air pollutants and CO_(2) emissions in urban road transport through 2035 in Chongqing, China

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Environmental Science and Ecotechnology 2021年第4期8卷 55-66页

作者： Linfeng Duan Wei Hu Di Deng Weikai Fang min xiong Peili Lu Zhenliang Li Chongzhi Zhai Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment Ministry of EducationChongqing UniversityChongqing400045PR China Department of Environmental Science College of Environment and EcologyChongqing UniversityChongqing400045PR China Chongqing Academy of Ecological and Environmental Science Chongqing401147PR China

The road transport sector in megacities is confronted with pressing local air pollution and carbon dioxide(CO_(2))control issues.To determine effective policy instruments for saving energy and the co-control of air pollutants and CO_(2),several mainstream measures were examined and compared in Chongqing's road transport sector from 2017 to 2035.An integration assessment framework was developed by combining the Long-range Energy Alternatives Planning(LEAP)system and a set of quantitative methods for evaluating the co-benefits of emission reductions(including the air pollutant equivalent(APeq),cocontrol coordinate system,and pollutant reduction cross-elasticity(Elsa/b)).Results showed that the shifting transportation modes scenario presented the most significant potential for energy-saving and emission reductions,reducing energy use by 30.9%and air pollutants and CO_(2) emissions by approximately 27e32%compared with the business as usual(BAU)scenario in 2035.The improving energy efficiency scenario also provided significant co-benefits for reducing air pollutants and CO_(2) emissions.Nevertheless,the promoting alternative fuel scenario may increase fine particulate matter(PM2.5)emissions by 2.2%compared to BAU in 2035 under the cleanness of regional electricity in 2017.Our findings suggest that the shifting transportation modes were effective measures to reduce air pollutants and CO_(2) in the short term synergistically,and highlighted the importance of cleaner electricity generation to develop electric vehicles in the medium and long term.

关键词： Co-benefits Air pollutants Carbon dioxide Energy consumption Road transport

具有时变刚度的骨折内固定植入物结构设计及骨重塑效果评估

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生物医学工程学杂志 2024年第3期41卷 595-603页

作者：孙浩丁晓红徐世鹏段朋云熊敏张横 .上海理工大学机械工程学院上海200093 上海市特种设备监督检验技术研究院上海200062

理想的骨折内固定植入物刚度应具有随时间变化的性能,使骨折在不同愈合阶段都能产生合理的力学刺激,可降解材料可以满足这一性能。考虑到材料降解过程的时间依赖性,提出一种具有时变刚度的骨折内固定植入物复合结构拓扑优化设计方法。... 详细信息

理想的骨折内固定植入物刚度应具有随时间变化的性能,使骨折在不同愈合阶段都能产生合理的力学刺激,可降解材料可以满足这一性能。考虑到材料降解过程的时间依赖性,提出一种具有时变刚度的骨折内固定植入物复合结构拓扑优化设计方法。采用相对密度和降解残留率描述两种具有不同降解速度和弹性模量的材料分布和降解状态,建立降解模拟-力学分析耦合数学模型;基于变密度法设计双材料复合结构,使之具有时变刚度特性。以胫骨骨折治疗用的接骨板为例,采用所提出方法设计具有时变刚度特性的复合结构接骨板,优化结果显示高刚度的材料1形成柱状的支撑结构,低刚度的材料2分布在降解边界和内部。利用骨重塑模拟模型对优化后的接骨板进行评估,经过11个月重塑,使用可降解时变刚度接骨板、钛合金接骨板和不锈钢接骨板的骨痂平均弹性模量分别为8634、8521、8412 MPa,表明使用可降解时变刚度接骨板可使骨痂取得更好的重塑效果。

关键词：拓扑优化时变刚度复合结构生物降解骨重塑

基于静息态功能MRI的认知储备对脑网络的影响研究

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医疗卫生装备 2024年第1期45卷 1-8页

作者：金悦熊敏林岚北京工业大学化学与生命科学学院生物医学工程系智能化生理测量与临床转化北京市国际科研合作基地北京100124

目的:基于静息态功能磁共振成像(rest state functional magnetic resonance imaging,rsfMRI)图像,探究认知储备对脑网络的影响。方法:首先,在英国生物银行中选择7973名健康中老年人的rsfMRI图像,通过独立成分分析得到21个静息态网络。... 详细信息

目的:基于静息态功能磁共振成像(rest state functional magnetic resonance imaging,rsfMRI)图像,探究认知储备对脑网络的影响。方法:首先,在英国生物银行中选择7973名健康中老年人的rsfMRI图像,通过独立成分分析得到21个静息态网络。其次,采用图论分析方法提取网络节点效率、最短路径长度以及节点度中心性等参数。最后,比较并分析静息态网络的活跃程度、网络节点效率、节点最短路径长度以及节点度中心性4个指标,以及这4个指标与受教育程度、早期流体智力、体育运动、休闲活动和社交程度5个认知储备代理指标之间的关系。结果:研究结果表明,受教育程度、早期流体智力和体育运动3个认知储备代理指标与多个静息态网络的活跃程度以及大多数认知控制网络和默认模式网络中的节点效率、节点度中心性之间存在显著的正相关关系,但与大多数认知控制网络和默认模式网络中的最短路径长度之间存在显著的负相关关系。而休闲活动和社交程度2个认知储备代理指标与静息态网络的活跃程度呈负相关关系,且对功能网络整体拓扑特性的影响也相对较小。结论:受教育程度、早期流体智力和体育运动对静息态网络具有重要促进作用,而休闲活动和社交程度这2个认知储备代理指标可能对静息态网络产生负面影响。

关键词：静息态功能磁共振成像认知储备脑网络静息态网络神经影像

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基于传力路径的接骨板结构拓扑优化设计

医用生物力学 2024年第3期39卷 442-449页

作者：蔡俊丁晓红段朋云熊敏张横上海理工大学机械工程学院上海200093

目的提出一种相对于传统拓扑优化方法能有效降低应力集中,并进一步提高断骨愈合效果的接骨板拓扑优化设计方法。方法依据接骨板在断骨-接骨板系统中的载荷约束条件,采用改进的基于传力路径的拓扑优化方法对接骨板结构进行优化设计。... 详细信息

目的提出一种相对于传统拓扑优化方法能有效降低应力集中,并进一步提高断骨愈合效果的接骨板拓扑优化设计方法。方法依据接骨板在断骨-接骨板系统中的载荷约束条件,采用改进的基于传力路径的拓扑优化方法对接骨板结构进行优化设计。随后采用基于偏应变的骨再生模拟模型,对胫骨骨干横向骨折情况进行骨再生模拟,依据骨再生过程数据对优化接骨板的受力状态、固定稳定性及愈合性能进行评估。结果使用基于传力路径优化方法的优化接骨板在体积分数f=0.55、0.65时,接骨板最大应力分别为55.68、42.23 MPa,相较于传统拓扑优化方法优化接骨板分别降低32.96%、29.95%;骨愈合过程后骨痂平均弹性模量分别为1 439.47、1 355.71 MPa,相较于传统接骨板分别提升145.86%、131.06%。结论提出的改进基于传力路径的拓扑优化方法,可以用于接骨板结构优化设计,优化后接骨板相比传统拓扑优化方法优化接骨板受力更加均匀,使用安全性更高,骨愈合性能相较传统接骨板有明显提升。研究结果为骨折内固定植入物的优化设计提供了一种新思路和方法。

关键词：传力路径接骨板拓扑优化结构设计