新型城市化建设和管理过程中,借助建筑信息模型(building information modeling,BIM)与地理信息系统(geographic information system,GIS)的数据集成,不但能实现建筑物的精细化表达,而且室外信息得以兼顾,实现空间分析及室内外一体化表...新型城市化建设和管理过程中,借助建筑信息模型(building information modeling,BIM)与地理信息系统(geographic information system,GIS)的数据集成,不但能实现建筑物的精细化表达,而且室外信息得以兼顾,实现空间分析及室内外一体化表达。但BIM与GIS两种不同的数据格式无法直接实现数据的互通。为此,首先分析了模型IFC和CityGML在文档形式等方面的差异,并实现了多个简单建筑物IFC模型到CityGML3.0 LOD2、LOD3的转换。其次,针对上述数据集成实验中语义丢失问题,扩展GIS的CityGML3.0数据格式,提出CityGML B-Con扩展模型,完善IFC到CityGML3.0的一对一映射关系。最后,实现多个不同复杂程度建筑物IFC模型到CityGML B-Con扩展模型的转换。实验结果表明,利用CityGML B-Con模型能实现BIM与GIS的数据集成。宏观层面来说,能够增强转换后建筑物外观的细节程度,微观层面而言,BuildingConstructiveElement和BuildingInstallation的子类得以区分,IfcStair、IfcRamp和IfcBeam等建筑构件都能通过一对一映射的方式转换至CityGML中,克服了CityGML原有标准在建筑物构件表达方面的缺陷,有效减少了BIM源数据语义信息的丢失。展开更多
The machinability of 4Cr13 steel was improved obviously by adding Cu and S. The effect of copper addition on the machinability of 4Cr13 was similar to that of sulphur addition. By means of SEM, EBSD, and HREM, the dis...The machinability of 4Cr13 steel was improved obviously by adding Cu and S. The effect of copper addition on the machinability of 4Cr13 was similar to that of sulphur addition. By means of SEM, EBSD, and HREM, the distribution and size of the free cutting phase in the steel 4Crl3Cu were studied. The results showed that the free cutting phase was copper-rich phase. The copper-rich phases dispersed in the steel and were determined to have about 10 nm in diameter. The content of copper in the copper-rich phase was over 70%.展开更多
文摘新型城市化建设和管理过程中,借助建筑信息模型(building information modeling,BIM)与地理信息系统(geographic information system,GIS)的数据集成,不但能实现建筑物的精细化表达,而且室外信息得以兼顾,实现空间分析及室内外一体化表达。但BIM与GIS两种不同的数据格式无法直接实现数据的互通。为此,首先分析了模型IFC和CityGML在文档形式等方面的差异,并实现了多个简单建筑物IFC模型到CityGML3.0 LOD2、LOD3的转换。其次,针对上述数据集成实验中语义丢失问题,扩展GIS的CityGML3.0数据格式,提出CityGML B-Con扩展模型,完善IFC到CityGML3.0的一对一映射关系。最后,实现多个不同复杂程度建筑物IFC模型到CityGML B-Con扩展模型的转换。实验结果表明,利用CityGML B-Con模型能实现BIM与GIS的数据集成。宏观层面来说,能够增强转换后建筑物外观的细节程度,微观层面而言,BuildingConstructiveElement和BuildingInstallation的子类得以区分,IfcStair、IfcRamp和IfcBeam等建筑构件都能通过一对一映射的方式转换至CityGML中,克服了CityGML原有标准在建筑物构件表达方面的缺陷,有效减少了BIM源数据语义信息的丢失。
基金Item Sponsored by Shanghai Leading Academic Discipline Project (T0101)Science and Technology Commission of Shanghai Project (065211028)
文摘The machinability of 4Cr13 steel was improved obviously by adding Cu and S. The effect of copper addition on the machinability of 4Cr13 was similar to that of sulphur addition. By means of SEM, EBSD, and HREM, the distribution and size of the free cutting phase in the steel 4Crl3Cu were studied. The results showed that the free cutting phase was copper-rich phase. The copper-rich phases dispersed in the steel and were determined to have about 10 nm in diameter. The content of copper in the copper-rich phase was over 70%.
