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长江经济带大气污染密集型企业时空格局演变及影响因素

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生态经济 2025年第1期41卷 221-229页

作者：代富强张霞赵鹏逸蔡元英陈俐雯重庆工商大学公共管理学院重庆400067 重庆工商大学经济学院重庆400067

产业集聚具有促进区域经济增长和产生环境污染的双重效应。基于“两控区”政策期间工业企业污染匹配数据,以长江经济带1998年、2005年、2012年大气污染密集型企业为研究对象,利用百度地图API接口进行企业地址匹配,运用GIS空间邻近分析... 详细信息

产业集聚具有促进区域经济增长和产生环境污染的双重效应。基于“两控区”政策期间工业企业污染匹配数据,以长江经济带1998年、2005年、2012年大气污染密集型企业为研究对象,利用百度地图API接口进行企业地址匹配,运用GIS空间邻近分析、空间自相关分析和空间计量模型研究大气污染密集型企业分布模式、空间集聚特征及其影响因素。研究发现:(1)长江经济带大气污染密集型企业数量不断增长,空间分布呈现明显的集聚特征,总体符合“中心—外围”结构模式;(2)区县大气污染密集型企业数量变化存在显著的正向空间自相关,热点区域为上海、江苏、浙江;(3)产业集聚对其企业数量时空变化的影响随时间逐渐增强,劳动力和边界效应与企业新增量关系显著,环境规制作用存在地区差异。

关键词：大气污染密集型企业产业集聚环境规制 SARAR模型长江经济带

EXTREMA OF A GAUSSIAN RANDOM FIELD:BERMAN'S SOJOURN TIME METHOD

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Acta Mathematica Scientia 2022年第5期42卷 1831-1842页

作者： liwen chen Xiaofan PENG School of Mathematical Sciences University of Electronic Science and Technology of ChinaChengdu 611731China

In this paper we devote ourselves to extending Berman’s sojourn time method,which is thoroughly described in[1-3],to investigate the tail asymptotics of the extrema of a Gaussian random field over[0,T]^(d) with T∈(0... 详细信息

关键词： tail asymptotics sojourn time Gaussian random field extreme stationarity

Dissolution and reprecipitation of 14H-LPSO structure accompanied by dynamic recrystallization in hot-extruded Mg_(89)Y_(4)Zn_(2)Li_(5) alloy

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Journal of Magnesium and Alloys 2023年第4期11卷 1408-1421页

作者： Wei Liu Yu Su Yuntao Zhang liwen chen Hua Hou Yuhong Zhao College of Materials Science and Engineering North University of ChinaTaiyuan 030051China

We investigate the variation induced in long-period stacking ordered(LPSO)structures,dynamic recrystallization(DRX),and mechanical performance of hot-extruded Mg89Y4Zn2Li5 alloys fabricated at different extrusion speeds(Ve=0.4,0.8,1.0,1.2 mm/s)and die angles(α=30°,60°,90°)under 400℃,the dissolution and reprecipitation of 14H LPSO structure accompanied by DRX process are then clarified in *** all extrusion conditions,the block 18R LPSO structures elongate in the extrusion direction,while the lamellar 14H LPSO structures dissolve under the deformation *** addition,due to discontinuous and continuous DRX mechanisms,all hot-extruded alloys have a full DRX microstructure consisting of equiaxed recrystallized grains,but the DRX grain size reduces when both extrusion speed and die angle *** that,in the interior of DRX grains,thin LPSO lamellae mixing 14H,18R and 24R structures nucleate and dynamically precipitate due to the dissolution of the original lamellar 14H LPSO ***,the hot-extruded Mg_(89)Y_(4)Zn_(2)Li_(5)alloy becomes stronger as decreasing of the extrusion speed and die angle,whereas the ductility remains nearly ***,the hotextruded Mg_(89)Y_(4)Zn_(2)Li_(5)alloy achieves an excellent strength-ductility balance at a relatively low extrusion speed(0.4 mm/s)and small die angle(30°)mainly due to the elongated 18R LPSO structure,fine and full DRX microstructure,thin mixed LPSO precipitates in the DRX grains,twins and dislocations.

关键词： Magnesium Extrusion LPSO Recrystallization Precipitation

Corrosion Behavior of Graphene Nanosheets Reinforced Magnesium Matrix Composites in Simulated Body Fluids

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 525-536页

作者： liwen chen Jianhui Jing Lulu Zhang Jing Li Weipeng chen Limin Li Yuan Zhao Hua Hou Yuhong Zhao School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-Performance Al/Mg Alloy MaterialsNorth University of ChinaTaiyuan 030051China Shanxi Key Laboratory of Advanced Manufacturing Technology School of Mechanical EngineeringNorth University of ChinaTaiyuan 030051China School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Magnesium(Mg)alloy is considered as a promising biodegradable implant material but restricted to rapid ***,the new strategies based on thixomolding process had been explored to utilize the outstanding anti-permeability of graphene nanosheets(GNPs)while inhibit its galvanic corrosion with the matrix,so as to improve the corrosion resistance of *** agglomerate of GNPs with 0.9 wt%content is the main reason for the deterioration of corrosion performance due to the formation of micro-galvanic *** grain refinement of composites with 0.6 wt%content had positive effects on the better corrosion *** process adjusting,the unique distributions of GNPs along grain boundaries play a vital role in improving the corrosion *** can be ascribed to the following mechanisms:(I)The barriers can be established between the Mg matrix and corrosive medium,hence blocking the charge transfer at the interface;(II)The GNPs can effectively promote apatite deposition on the Mg matrix,leading to form dense apatite layers and prevent the further invasion of SBF;(III)The GNPs acting as reinforcements exists in the corrosion layer and apatite layer,impede the apatite layer falling off from the Mg *** findings broaden the horizon for biomedical applications in Mg matrix composites to realize desired performances.

关键词： Magnesium matrix composite Graphene nanosheets Corrosion resistance

Risk assessment of agricultural green water security in Northeast China under climate change

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Science China Earth Sciences 2024年第7期67卷 2178-2194页

作者： Jingxuan SUN Guangxin ZHANG Yanfeng WU liwen chen Peng QI Boting HU Yijun XU Northeast Institute of Geography and Agroecology.Chinese Academy of Sciences Changchun 130102China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Black Soils Conservation and Utilization Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China School of Renewable Natural Resources Louisiana State University Agricultural Center227 Highland RoadBaton RougeLA 70803USA

Northeast China is an important base for grain production,dominated by rain-fed agriculture that relies on green ***,in the context of global climate change,rising regional temperatures,changing precipitation patterns,and increasing drought frequency pose threats and challenges to agricultural green water *** study provides a detailed assessment of the spatiotemporal characteristics and development trends of green water security risks in the Northeast region under the base period(2001-2020)and the future(2031-2090)climate change scenarios(SSP245 and SSP585)using the green water scarcity(GWS)index based on raster-scale crop spatial distribution data,Delta downscaling bias-corrected ERA5 data,and CMIP6 multimodal *** the base period,the green water risk-free zone for dry crops is mainly distributed in the center and east of the Northeast region(72.4% of the total area),the low-risk zone is primarily located in the center(14.0%),and the medium-risk(8.3%)and high-risk(5.3%)zones are mostly in the *** SSP245 and SSP585 future climate change scenarios,the green water security risk shows an overall expansion from the west to the center and east,with the low-risk zone increasing to 21.6% and 23.8%,the medium-risk zone increasing to 16.0% and 17.9%,and the high-risk zone increasing to 6.9% and 6.8%,*** dry crops with GWS greater than 0.1 as in need of irrigation,the irrigated area increases from 27.6%(base period)to 44.5%(SSP245)and 48.6%(SSP585),with corresponding increases in irrigation water requirement(IWR)of 4.64 and 5.92 billion m~3,respectively,which further exacerbates conflicts between supply and demand of agricultural water *** response to agricultural green water security risks,coping strategies such as evapotranspiration(ET)-based water resource management for dry crops and deficit irrigation are *** results of this study can provide scientific basis and decision support for the development

关键词： Climate change Food security Green water security risk Irrigation water requirement Green water scarcity

Research on heat dissipation characteristics of magnetic fluid bearings under multiple field coupling effects

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High Technology Letters 2024年第3期30卷 263-270页

作者： chen liwen WU Weiying GAO Dianrong ZHAO Jianhua CUI Bingyan College of Mechanical Engineering North China University of Science and TechnologyTangshan 063210P.R.China College of Mechanical Engineering Yanshan UniversityQinhuangdao 066000P.R.China

This paper analyzes the sources of heat losses in magnetic fluid bearings,proposes various cou-pling relationships of physical fields,divides the coupled heat transfer surfaces while ensuring the continuity of heat flux density,and analyzes the overall heat dissipation pathways of the *** changing parameters such as input current,rotor speed,and inlet oil flow rate,the study applies a multi-physics field coupling method to investigate the influence of different parameters on the temper-ature field and heat dissipation patterns of the bearings,which is then validated through *** research provides a theoretical basis for the optimal design of magnetic fluid bearing sys-tems.

关键词： magnetic fluid bearing multi-physics field coupling multiple parameter varia-tion heat dissipation pattern

Telling China's story through reports on major manned space activities: A case study of the coverage of Shenzhou spacecraft in Chinese and Western media

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Cultures of Science 2022年第2期5卷 101-118页

作者： Min Zhou liwen chen Ji Zhao Beijing Normal University National Academy of Innovation Strategy

The Shenzhou spacecraft have been independently developed by China, and the country has complete intellectual property rights to this technology. The spacecraft are examples of China’s achievements in space technology, are representative of the country having reached or surpassed international technological standards for third-generation manned spacecraft, and have garnered widespread interest among international media and audiences. Our study found that there are many differences between Chinese and Western media in their coverage of this major topic. China’s reporting system on this issue is well established but still has room for improvement. Western media have considered both positive and negative angles when reporting on this issue, and that deserves attention. In these circumstances, it is important for China to improve its communicators, communication content, information release mechanisms, narrative style and response mechanism through targeted measures, such as cultivating new communicators, developing new content and minimizing cultural discounts in cross-cultural communication in order to enhance China’s voice on the world stage.

关键词： Shenzhou spacecraft national image media

A digital microfluidic single-cell manipulation systemoptimized by extending-depth-of-field device

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Journal of Innovative Optical Health Sciences 2023年第3期16卷 43-55页

作者： Qiushu chen Qi Meng Yuzhe Liu Xiangan Long Yawei Kong Longfang Yao liwen chen Chuanyong Wu Kaiqin Chu Lan Mi Jiong Ma Department of Optical Science and Engineering Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing Key Laboratory of Micro and Nano Photonic Structures(Ministry of Education)School of Information Science and Technology Fudan University Shanghai 200433P.R.China Department of Precision Machinery and Precision Instrumentation University of Science and Technology of China Hefei 230027 AnhuiP.R.China Institute of Biomedical Engineering and Technology Academy for Engineering and Technology Fudan University Shanghai 200433P.R.China Institute of Photonic Chips Centre for Articial-Intelligence Nanophotonics School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology Shanghai 200093 P.R.China Ruidge Biotech Co.Ltd. No.888Huanhu West 2nd Road Lin-Gang Special AreaChina(Shanghai)Pilot Free Trade Zone Shanghai 200131P.R.China Shanghai Hengxin BioTechnology Ltd.1688 North Guo Quan RdBldg A8Rm 801 Shanghai 200438P.R.China Centre for Articial-Intelligence Nanophotonics School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology Shanghai 200093 P.R.China Shanghai Engineering Research Center of Industrial Microorganisms The Multiscale Research Institute of Complex Systems(MRICS)School of Life SciencesFudan UniversityShanghai 200433P.R.China

Microfuidic systems have been widely utilized in high-throughput biology analysis,but thedificulties in iquid manipulation and cell cultivation limit its *** work has developed a new digital microfluidic(DMF)system for on-demand droplet *** adopting anextending-depth-of-field(EDoF)phase modulator to the optical system,the entire depth of themicrofluidic channel can be covered in one image without any refocusing process,ensuring that 95%of the particles in the droplet are captured within three shots together with shaking *** this system,suspension droplets are generated and droplets containing only oneyeast cll can be recognized,then each single cell is cultured in the array of the *** growth in cell numbers and the green fluorescence protein(GFP)production via fluorescence imaging,the single cell with the highest production can be *** results haveproved the heterogeneity of yeast cells,and showed that the combined system can be applied forrapid single-cell sorting,cultivation,and analysis.

关键词： Single-cell analysis digital microfluidic(DMF) extending-depth-of-field system

A review: Panax ginseng diseases and the control techniques

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Asian Journal of Traditional Medicines 2022年第4期17卷 186-191页

作者： Mo Yao liwen chen Luming Pan Haonan Yu Yuhang Liu Miao Wang Yu chen School of Life Science and Biopharmaceutics Shenyang Pharmaceutical UniversityShenyang 110016China

Panax ginseng(***)is a famous traditional medical plant,with both the medical and economic *** China,the cultivation of *** is a major agricultural ***,the yield and quality have declined in recent years due to various *** review summarized the common diseases of *** and the controlling techniques,aiming to enhance the cultivation of *** and ensure the sustainable development of *** industry.

关键词： Panax ginseng disease control technique