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空间污名化过程与形成机制研究

地理学报 2024年第6期79卷 1449-1463页

作者：李巍杨文王录仓漆建武王宗相西北师范大学地理与环境科学学院兰州730070 华南理工大学旅游管理系广州510000 华南理工大学数字乡村与文旅可持续发展重点实验室广州510000

身份污名化与领土污名化研究由来已久,但对于二者之间互动关系的探讨却相对不足。本文在回溯和梳理污名化由来的基础上,试图从地理学视角探讨人—地污名化的关系,并提出空间污名化的概念,系统诠释了空间污名化的地理过程与形成机制。研... 详细信息

身份污名化与领土污名化研究由来已久,但对于二者之间互动关系的探讨却相对不足。本文在回溯和梳理污名化由来的基础上,试图从地理学视角探讨人—地污名化的关系,并提出空间污名化的概念,系统诠释了空间污名化的地理过程与形成机制。研究认为:①空间污名化是在特定的历史环境与认知水平下,施污者通过贬低地方的感知价值与身份构建,对空间及其依附的人和物进行不全面、不准确、不客观的认知过程,从而形成符号化的污名指向。②在地理空间格局的异质性背景下,空间污名化具有意象构建、主体分离、群体互动、空间定位以及符号化的过程,并在不同方向、距离与尺度上,形成本地或异地的直接污名化和间接污名化类型。③空间不平等、权利剥削与斗争、恐惧与逃避以及恋地与社会秩序是空间污名化的基础,人—地间通过感知、识别、定位与标记的复杂互动,推动污名化的空间集中与内化,这就形成了产生、传播、反应与再生产不断循环的空间污名化机制。面对普遍的空间污名化现状,解决的关键在于重建新的叙事体系,正确认识人地关系,最终在“人类命运共同体”意识的倡导下实现“去空间污名化”。

关键词：空间污名化人地关系过程形成机制

Mechanical properties and energy evolution of jointed rock specimens containing an opening under uniaxial loading

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International Journal of Minerals,Metallurgy and Materials 2021年第12期28卷 1875-1886页

作者： Peng li Mei-feng Cai Pei-tao wang Qi-feng Guo Sheng-jun Miao Fen-hua ren school of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory of High-Efficient Mining and Safety of Metal Mines(Ministry of Education of china) University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Urban Underground space Engineering University of Science and Technology BeijingBeijing 100083China

To investigate the impact of an opening and joints with different inclination angles on the mechanical response behavior,the energy evolution characteristics,and distribution law of granite specimens,uniaxial loading tests were performed on the parallel jointed rock samples with an *** indicated an initial decreasing trend of the strength and deformation parameters,which later increases with increased inclination angle,reaching minimum values when the inclination angle is 45°.Evolution curves of the elastic strain energy and dissipated energy with strain of the samples showed step-like gradual mutation *** peak total energy,peak elastic strain energy,peak dissipated energy,and total input energy during the failure of the samples showed significant nonlinear characteristics with increasing inclination *** opening and joints as well as the change of the inclination angle had significant influences on the proportion of the elastic strain energy of the samples prior to the peak,resulting in the difference of the distribution law of input ***,the energy mechanism of the sample failure was *** showed that the energy release was the internal cause of the sudden destruction of the entire rock mass.

关键词： deformation energy rock

Development and application of wellbore heat transfer model considering variable mass flow

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Underground space 2021年第3期6卷 316-328页

作者： Jiangshuai wang jun li Gonghui liu Shujie liu Meipeng ren Kuidong Luo Shanxun Tao school of Petroleum Engineering Changzhou UniversityChina College of Petroleum Engineering China University of Petroleum(Beijing)China College of Petroleum China University of Petroleum(Beijing)at KaramayChina CNOOC Research Institute Co. Ltd.China

Dual-gradient drilling technology is being increasingly used in formations with narrow pressure *** dual-gradient drilling based on downhole separation,hollow spheres are separated into the annulus at the separator position,resulting in variable mass flow in the ***,existing heat transfer models are no longer suitable for describing wellbore temperature profiles in dual-gradient *** study focused on developing a wellbore heat transfer model that fully considers separated hollow spheres entering the annulus,complex casing programs,and heat sources,for dual-gradient drilling based on downhole *** model was solved using an iterative ***,the accuracy of the model was verified using temperature data measured from two ***,the difference in the annular temperature distributions between dual-gradient drilling and conventional single-gradient drilling were investigated,as were the wellbore heat transfer characteristics for dual-gradient *** following major conclusions were drawn:(1)for dualgradient drilling based on downhole separation,at the separator location,the annular fluid temperature does not decrease,but rather increase in the flow direction because of the inflow of hollow spheres;(2)a clear inflection point exists in the annular fluid temperature curve at the location where the separator would be;(3)the magnitude of the mutation of the temperature curve at the inflection point is considerably affected by the heat capacities of the hollow spheres and the pure drilling fluid;(4)under the same change in separation efficiency,distance between the bit and separator,flow rate,and thermal conductivity of formation,the variation range of the fluid temperature at the bottom hole is greater than that at the wellhead.

关键词： Dual-gradient drilling Heat transfer Downhole separation Hollow sphere Annular temperature distribution

山东地区场地剪切波速经验外推模型及其适用性

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地震地质 2024年第4期46卷 934-954页

作者：李志恒谢俊举李柯苇温增平李小军王志才许洪泰赵晓芬张娜中国地震局地球物理研究所北京100081 山东省地震局济南250014 北京大学地球与空间科学学院北京100871 北京工业大学城市建设学部北京100124

场地剪切波速是进行场地分类和定量估计场地对地震动影响的重要参数,在工程抗震设防和震后震害快速评估等方面具有广泛应用。文中利用山东地区1336个工程场地的剪切波速剖面数据,分别基于常速度外推方法、速度梯度外推方法和条件独立方... 详细信息

场地剪切波速是进行场地分类和定量估计场地对地震动影响的重要参数,在工程抗震设防和震后震害快速评估等方面具有广泛应用。文中利用山东地区1336个工程场地的剪切波速剖面数据,分别基于常速度外推方法、速度梯度外推方法和条件独立方法建立了山东地区场地剪切波速V_(S20)和V_(S30)的经验外推模型。研究结果表明,常速度外推方法对较浅的钻孔进行波速外推时会产生明显的低估,且预测误差较大。速度梯度外推方法的拟合结果表现出明显的区域性特征,山东地区的V_(S30)预测结果与美国加州和北京平原地区的结果相比,总体上较为接近,但明显低于日本地区。综合考虑建立的3种区域外推模型的精度和预测误差,文中建议优先采用基于条件独立方法建立的山东地区的V_(S20)和V_(S30)经验外推模型,获得的波速外推结果可以较好地为山东地区场地分类提供依据。

关键词：场地分类外推模型平均剪切波速适用性 V_(S30)

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Agglomeration behavior of rare earth inclusions and alumina inclusions at the interface between argon and molten steel

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Journal of Rare earths 2023年第12期41卷 2033-2040,I0008页

作者： jun wang linzhu wang Changrong li Yongqiang Zhai school of Materials and Metallurgy Guizhou UniversityGuiyang550025China Steel Rolling Division Shougang Group Shuicheng Steel CompanyLiupanshui553000China

Nozzle clogging frequently occurs in steel containing rare earth(RE) due to the aggregation of RE inclusions,which seriously interferes with the application of RE in *** provide insights into nozzle clogging,the agglomeration be havior of inclusions in RE-containing steel was investigated by laboratory experiments and theoretical ***-temperature confocal laser scanning microscopy(HTCLSM) was applied to observe the behavior of inclusions at molten steel surfaces and their interactive ***-Paunov(K-P) model was used to predict the capillary force acting on different *** results show that the interactive forces that acted on inclusions were investigated as a function of inclusion size,inter-distance,and inclusion *** is found that the capillary force acting on the inclusions decreases in the order of Ce_(2)O_(3)> CeAlO_(3)> Al_(2)O_(3).This study verified the applicability of the K-P model in RE-containing steel,which can provide theoretical support to help solve the nozzle clogging problem during rare earth steel production.

关键词： Agglomeration Inclusion Rareearths Capillaryforce

2~6 GHz 100 W高效率平衡式功率放大器的研制

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电子科技大学学报 2024年第1期53卷 8-13页

作者：来晋明徐会博李志友倪涛王超杰银军王海龙马晓华西安电子科技大学微电子学院西安710071 中国电子科技集团公司第二十九研究所成都610036 中国电子科技集团公司第十三研究所石家庄050050

为解决传统宽带大功率放大器工作效率低的问题,采用新型电阻电抗连续B/J类功放模式拓展晶体管高效率的输出负载阻抗空间,从而提高宽带功放的漏级输出效率。提出了一款基于0.25μm栅长的氮化镓高电子迁移率晶体管(GaN HEMT)的平衡式功放... 详细信息

为解决传统宽带大功率放大器工作效率低的问题,采用新型电阻电抗连续B/J类功放模式拓展晶体管高效率的输出负载阻抗空间,从而提高宽带功放的漏级输出效率。提出了一款基于0.25μm栅长的氮化镓高电子迁移率晶体管(GaN HEMT)的平衡式功放。该功放将LC匹配网络和切比雪夫阻抗变换器相结合实现GaN HEMT器件宽带输入输出阻抗匹配,并利用3 dB Lange耦合器实现宽带平衡式功率合成。在连续波测试条件下,该平衡式功放在2~6 GHz频带内输出功率大于100 W,漏极效率大于45%,功率增益大于9.0 dB,抗负载失配比优于5:1。

关键词： GaN HEMT 宽带平衡式功率合成功率放大器

Clarification of underneath capacity loss for O3-type Ni, co free layered cathodes at high voltage for sodium ion batteries

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Journal of Energy Chemistry 2023年第2期77卷 479-486,I0012页

作者： Dong Zhou De Ning jun wang Jiahua liu Gaoyuan Zhang Yinguo Xiao Jiaxin zheng Yongli li Jie li Xinzhi liu Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices School of PhysicsSun Yat-sen UniversityGuangzhou 510275GuangdongChina school of Innovation and Entrepreneurship Southern University of Science and TechnologyShenzhen 518055GuangdongChina Centre for Photonics Information and Energy Materials Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055GuangdongChina school of Advanced Materials Peking University Shenzhen Graduate SchoolShenzhen 518055GuangdongChina Institute for Clean Energy technology North China Electric Power UniversityBeijing 102206China Department of Energy Politecnico di MilanoVia Lambruschini 4Milano 20156Italy Centre for Physical Mechanics and Biophysics School of PhysicsSun Yat-sen UniversityGuangzhou 510275GuangdongChina

earth abundant O3-type NaFe_(0.5)Mn_(0.5)O_(2)layered oxide is regarded as one of the most promising cathodes for sodium ion batteries due to its low cost and high energy ***,its poor structural stability and cycle life strongly impede the practical ***,the dynamic phase evolution as well as charge compensation mechanism of O3-type NaFe_(0.5)Mn_(0.5)O_(2)cathode during sodiation/desodiation are revealed by a systemic study with operando X-ray diffraction and X-ray absorption spectroscopy,high resolution neutron powder diffraction and neutron pair distribution *** layered structure experiences a phase transition of O3→P3→OP2→ramsdellite during the desodiation,and a new O3’phase is observed at the end of the discharge state(1.5 V).The density functional theory(DFT)calculations and nPDF results suggest that depletion of Na^(+)ions induces the movement of Fe into Na layer resulting the formation of an inert ramsdellite phase thus causing the loss of capacity and structural ***,the operando XAS clarified the voltage regions for active Mn^(3+)/Mn^(4+)and Fe^(3+)/Fe^(4+)redox *** work points out the universal underneath problem for Fe-based layered oxide cathodes when cycled at high voltage and highlights the importance to suppress Fe migration regarding the design of high energy O3-type cathodes for sodium ion batteries.

关键词： Sodium ion batteries Layered oxide cathode Iron migration Operando X-ray absorption spectroscopy Neutron measurements

Simultaneous refinement of α-Mg grains and β-Mg_(17)Al_(12) in Mg-Al based alloys via heterogeneous nucleation on Al_(8)Mn_(4)Sm

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Journal of Magnesium and Alloys 2023年第1期11卷 348-360页

作者： jun-Chen Chen Mei-Xuan li Zhi-Yang Yu Zhao-Yuan Meng Cheng wang Zhi-zheng Yang Hui-Yuan wang State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130012PR China Key Laboratory of Automobile Materials of Ministry of Education&school of Materials science and Engineering Jilin UniversityNanling CampusNo.5988 Renmin StreetChangchun 130025PR China International Center of Future science Jilin UniversityChangchun 130012PR China

Due to the significant differences in the formation temperature and crystal structure between the primaryα-Mg and eutecticβ-Mg_(17)Al_(12),it is a great challenge to achieve simultaneous refinement of the primary and eutectic phases in Mg-Al based alloys via heterogeneous ***,we found that theα-Mg andβ-Mg_(17)Al_(12) in the AZ80 alloy can be simultaneously refined after 0.2 wt.%Sm addition,with the grain size decreasing from∼217±15μm to∼170±10μm and theβ-Mg_(17)Al_(12) morphology changing from a typical continuous network to a nod-like or spherical *** simultaneous refinement mechanism is investigated through solidification simulation,transmission electron microscopy(TEM),and differential thermal analysis(DTA).In the AZ80-0.2Sm alloy,many Al8Mn4Sm particles can be observed near the center of theα-Mg grains or inside theβ-Mg_(17)Al_(12).Crystallographic calculations further reveal that the Al8Mn4Sm has good crystallographic matching with both theα-Mg andβ-Mg_(17)Al_(12),so it possesses the potency to serve as heterogeneous nucleation sites for both *** promoted heterogeneous nucleation on the Al8Mn4Sm decreases the undercooling required by the nucleation of the primary and eutectic phases,which enhances the heterogeneous nucleation rate,thus causing the simultaneous refinement of theα-Mg andβ-Mg_(17)Al_(12).The orientation relationships between the Al8Mn4Sm and Mg/Mg_(17)Al_(12) are identified,which are[1210]_(Mg)//[010]_(Al8Mn4Sm),(1010)_(Mg)//(301)_(Al8Mn4Sm) and[112]_(Mg_(17)Al_(12))//[010]_(Al8Mn4Sm),(110)_(Mg_(17)Al_(12))//(301)_(Al8Mn4Sm),***,the refinement of theβ-Mg_(17)Al_(12) accelerates its dissolution during the solution treatment,which is beneficial for cost saving in industrial *** Al8Mn4RE compounds such as Al8Mn4Y might have the same positive effect on the simultaneous refinement due to the similar physicochemical properties of rare earth *** work not only proves the po

关键词： Magnesium alloys Microstructure refinement Primaryα-Mg Eutecticβ-Mg_(17)Al_(12) Rare earth Heterogeneous nucleation

面向BIM的室内拓扑-栅格分层路径规划方法

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测绘通报 2024年第3期 81-87页

作者：郭瑞荣李朝奎李豪陈军湖南科技大学地理空间信息技术国家地方联合工程实验室湖南湘潭411201 湖南科技大学地球科学与空间信息工程学院湖南湘潭411201 湘潭金豪软件开发有限公司湖南湘潭411100 湖南兴天电子科技股份有限公司湖南长沙410006

针对传统路径规划方法在复杂大场景环境下的搜索空间大、效率低、避障安全性差等问题,本文提出了一种基于BIM的室内拓扑-栅格分层路径规划方法。首先,建立复杂室内环境的BIM模型,提取模型中结构、障碍物和通道的语义、几何及其关联信息... 详细信息

针对传统路径规划方法在复杂大场景环境下的搜索空间大、效率低、避障安全性差等问题,本文提出了一种基于BIM的室内拓扑-栅格分层路径规划方法。首先,建立复杂室内环境的BIM模型,提取模型中结构、障碍物和通道的语义、几何及其关联信息,通过栅格抽象映射得到基础导航地图,并结合层次图思想,开展地图空间分层,获取拓扑-栅格分层地图;然后,利用细化算法,生成拓扑层中各子区域之间的离线先验路网,联合Dijkstra算法选取其中的最优路径,并基于自主改进的A*算法,快速高效搜索栅格层的最优路径,通过组合拼接拓扑层与栅格层的局部最优路径,构建完整的全局最优路径;最后,将本文方法与标准A*算法及蚁群算法作对比,在保证计算效率的同时,不仅缩小了路径搜索空间,还确保了最优路径的安全性,综合验证了所提路径规划方法的优越性。

关键词： BIM 语义信息路径规划 Dijkstra算法改进A*算法