Hot Deformation Behavior of a New Nuclear Use Reduced Activation Ferritic/Martensitic Steel

The hot deformation behavior and workability of a new reduced activation ferritic/martensitic steel named SIMP steel for accelerator-driven system were studied.The flow curve and its microstructure were studied at 900-1200℃ and strain rate range of 0.001-10 s~(-1).The results showed that the deformation behavior of the SIMP steel during hot compression could be manifested by the Zener-Hollomon parameter in an exponent-type equation.Based on the obtained constitutive equation,the calculated flow stresses were in agreement with the experimentally measured ones,and the average activity energies QDRV and QHW for the initiation of dynamic recrystallization and the peak strain were calculated to be 476.1 kJ/mol and 462.7 kJ/mol,respectively.Furthermore,based on the processing maps and microstructure evolution,the optimum processing condition for the SIMP steel was determined to be 1050-1200 ℃/0.001-0.1 s~(-1).     

Hot Deformation Behavior and Processing Map of a Cu-Bearing 2205 Duplex Stainless Steel

The hot deformation behavior and processing map of Cu-bearing 2205 duplex stainless steel(2205-Cu DSS) were investigated at temperatures of 950-1150℃and strain rates of 0.01-10 s~(-1).The effects of Cu addition and different deformation parameters on deformation behavior were,respectively,characterized by analyzing flow curves,constitutive equations and microstructures.The results indicated that the shapes of flow curves strongly depended on the volume fraction of two phases.When deformed at low strain rate,DRV in ferrite was prompted with increase in the temperature and was further developed to continuous DRX.At high strain rate,flow localization preferentially occurred in ferrite at low deformation temperature due to the strain partitioning and relatively less fraction of ferrite.The activation energy for 2205-Cu DSS was 452 kJ/mol and was found to connect with the variation of strain,strain rate and deformation temperature.The optimum hot deformation parameters for 2205-Cu DSS were obtained in the temperature range of 1100-1150℃and strain rate range of 0.1-1 s~(-1)with a peak power dissipation efficiency of 41%.Flow localization was the main way to lead to flow instability.Meanwhile,the Cu-rich precipitates were generated within a few ferrite grains when deformed at temperature lower than 1000℃.The interaction between dislocations and Cu-rich precipitates at high strain rate,as well as the limited DRV in ferrite and DRX in austenite,contributed to the complex microstructure and flow behavior.     

基于电子地图辅助视觉导航的AGV设计

文章介绍了一种基于电子地图辅助视觉导航的自动导向车(AGV)的结构、功能及工作原理,并详细介绍了电子地图的表示、电子地图辅助方法及该AGv的优点.在电子地图中采用虚拟标志符区分柔性生产线中的分支路径,来引导AGV在正确的分支路径上行走.     

GPS RTK技术在水下地形图测量中的应用

详细介绍了利用GPSRTK技术与数字测深仪结合组成的水下地形测量系统的工作原理,简单介绍了利用该系统作业时的外业数据采集、内业数据处理的过程,总结了应用该系统进行作业的优点以及应注意的事项.     

基于历史地图解译的崇州罨画池水系演变研究

用历史地图空间解译法先梳理了清光绪至20世纪80年代崇州城市水系的演变,再结合罨画池相关文献,复原了清康熙、道光、光绪时期罨画池水体形态与体系的演变过程图,并从城市水系与园林兴衰、园林的功能使用、水体形态的系统性三方面归纳总结水系演变特点:1)崇州城市水系促成罨画池的形成,也决定其衰败;2)罨画池从以游赏为主的衙署园林最终变为以纪念为主的公共园林;3)罨画池水体系统性的形成深受园林建设的影响。     

超大城市行政区气候环境敏感性多尺度 影响机制可视化与对策研究——以北京市 丰台区为例

气候环境研究具有多尺度层级的特征，城市气候环境改善需要从不同尺度关注不同层面问题，已有诸多研究成果表明，城市物理环境对气候改善具有决定性作用。以存量时代城市更新改造为背景，从“多尺度”视角切入，重点关注城市气候环境改善在不同尺度层级的途径与方法，共同指导城市更新改造的具体操作。以北京市丰台区为研究对象，利用城市环境气候地图分析城市片区内气候环境敏感性分级。首先，对建成环境影响要素进行综合分析，结果显示，丰台区中部气候环境敏感性高的区域，其建筑密度大、建筑高度高、植被覆盖率低、路网密度高。其次，引入网格化分割降级气候环境分析尺度，将敏感单元落在城市街区尺度内，研究得到丰台区5个气候高敏感片区，其中4个为批发市场城市功能，具有典型性。最后，针对典型敏感片区建成环境特征，总结街区改造策略，提出多尺度气候环境分析的重要性，以及基于微气候改善的精细化途径，这是存量时代城市应对气候环境变化的有效方案。     

视觉传达理论在丝绸地图中的应用研究

丝绸地图作为一种新形式的地图产品,在地图视觉传达上与普通的纸质介质不同,只有正确处理好地理信息与表现方法的关系,才能将丝绸与地图完美的结合起来,更好的达到向大众传达信息的目的。     

Patterning ecological risk of pesticide contamination at the river basin scale

Ecological risk assessment was conducted to determine the risk posed by pesticide mixtures to the Adour-Garonne river basin (south-western France). The objectives of this study were to assess the general state of this basin with regard to pesticide contamination using a risk assessment procedure and to detect patterns in toxic mixture assemblages through a self-organizing map (SOM) methodology in order to identify the locations at risk. Exposure assessment, risk assessment with species sensitivity distribution, and mixture toxicity rules were used to compute six relative risk predictors for different toxic modes of action: the multi-substance potentially affected fraction of species depending on the toxic mode of action of compounds found in the mixture (msPAF CA_TMoA values). Those predictors computed for the 131 sampling sites assessed in this study were then patterned through the SOM learning process. Four clusters of sampling sites exhibiting similar toxic assemblages were identified. In the first cluster, which comprised 83% of the sampling sites, the risk caused by pesticide mixture toward aquatic species was weak (mean msPAF value for those sites < 0.0036%), while in another cluster the risk was significant (mean msPAF < 1.09%). GIS mapping allowed an interesting spatial pattern of the distribution of sampling sites for each cluster to be highlighted with a significant and highly localized risk in the French department called “Lot et Garonne”. The combined use of the SOM methodology, mixture toxicity modelling and a clear geo-referenced representation of results not only revealed the general state of the Adour-Garonne basin with regard to contamination by pesticides but also enabled to analyze the spatial pattern of toxic mixture assemblage in order to prioritize the locations at risk and to detect the group of compounds causing the greatest risk at the basin scale.     

晚清热河避暑山庄河工考述

避暑山庄与热河河工息息相关.利用档案资料系统地考证了清代热河河工舆图"热河城外河山图"的具体绘制时间与作者,并对于其所绘信息进行了解析.全面识读并分析了刊刻于1888年的热河河工碑碣——"避暑山庄宫墙及武列河堤坝各工程碑""武列河西崖大坝岁修章程碑".梳理了该河工舆图、碑碣所记载的河工始末,1884-1888年先后2期...     

论大型挂图的设计与实现

本文以《福州市中心城区挂图》编制为例,论述大型办公挂图设计思想、技术路线、工艺流程,着重阐述办公挂图编制中地图内容选择与表示、地貌的立体表示、符号设计等关键环节,探讨解决办法与对策。