全极化SAR影像城区建筑密度分析

针对全极化SAR影像的建筑区特性,提出了一种基于极化特征共生矩阵的城区建筑密度分析方法。首先将极化特征与共生矩阵结合,在考虑建筑区极化散射机理和建筑朝向作用的同时,兼顾了建筑区的空间排列信息,在此基础上为了增强建筑密度的局部区域特性,将共生矩阵特征进行K-means聚类,结合图像分块形成标号直方图统计矢量,进而对该直方图统计矢量进行矢量量化实现SAR影像城区的建筑密度分级。RadarSat-2全极化SAR影像城区建筑密度分析的实验表明,该方法既适用于建筑朝向复杂城区也适用于建筑排列整齐城区的密度信息提取。     

不同冷速下36Mn2V钢坯高温塑性及碳氮化物的析出

采用Gleeble-1500热模拟试验机研究了微合金钢36Mn2V连铸坯试样在冷速为3、8和15℃/s,变形温度为650～1000℃/s之间的高温塑性,并通过试样的断口形貌、显微组织和微合金析出相等的变化情况分析其脆化机理。结果表明：实验钢的第Ⅲ脆性温度区为950～650℃/s,800℃以上脆化是由碳氮化物单一原因造成,800℃以下脆化的原因则是碳氮化物的析出和沿晶界铁素体膜的形成;冷速过快加剧900～700℃温度区间的脆化;900℃已有大量碳氮化物的析出,随变形温度的降低,析出量减少,750℃仍然存在碳氮化物的析出。     

Multi-ontology fusion and rule development to facilitate automated code compliance checking using BIM and rule-based reasoning

Code compliance checking plays a critical role that identifies substandard designs according to regulatory documents and promises the accuracy of the designs before construction. However, the traditional code compliance checking process relies heavily on human work. To help the users better understand the checking process, this study proposes a gray-box checking technique and a BIM-based (Building Information Modeling) automated code compliance checking methodology that leverages ontology. The proposed approach contains a code ontology, a designed model ontology, a merged ontology, a code compliance checking ontology, a set of mapping rules, and a set of checking rules. During the checking process, the ontologies provide knowledge bases, and the rules provide necessary logic. A five-step roadmap is proposed for code ontology development for domain experts. For the time being, pre-processing is applied to create the designed model ontology to achieve time saving. Next, an ontology mapping procedure between the code and the designed model ontology is executed to obtain the merged ontology. In the ontology mapping procedure, the mapping rules aim to mitigate the semantic ambiguity between design information and regulatory information and enrich building information's semantics. Subsequently, rule-based reasoning is applied based on the checking rules and the merged ontology for checking reports generation. Finally, according to Chinese building codes, an automated code compliance checking platform is implemented for real construction projects to validate the proposed methodology.     

面向定制化装配式建筑的制造与装配设计策略研究 ——以莲花之居为例

针对建筑师缺乏关于定制化装配式建 筑制造与装配的技术认知与研究前置等问题, 文章旨在通过面向制造与装配的设计（DfMA） 理论探索,建构适用于建筑领域的DfMA策 略。策略研究分实施基础、面向制造的设计 （DfM）和面向装配的设计（DfA）三部分,并 基于莲花之居进行实践验证以形成实施框架, 从而为建筑师提供面向定制化装配式建筑的 DfMA策略指导与设计建造流程参考。     

新产品研发是建陶企业可持续发展的核心

新世纪我国建陶企业在整个国民经济的带动下将进一步发展，入世后经济全球化的市场竞争格局，建陶企业只有走新产口研发之路，严格企业管理，才会在日趋激烈的市场竞争中得以生存和可持续发展。     

超轻镁合金板坯直冷连铸三维温度场数值模拟

运用有限差分法,对超轻Mg-Li合金(LA141)板坯直冷连铸过程温度场进行数值模拟,根据实际过程的物理现象以及文献资料确定包括一冷区、二冷区在内的边界条件,并且考虑底模与铸坯之间随着铸坯的变形而引起的换热系数的变化.通过计算铸坯内温度场的分布,固-液界面的形状和位置,分析各种铸造参数,包括浇注温度、冷却水量、铸造速度等对连铸过程的影响.另外也比较了在同等铸造条件下LA141铸坯和AZ31铸坯铸造过程中凝固前沿的形状.     

Spectral analysis of surface wave response of multi-layer thin cement mortar slab structures with finite thickness

The method of spectral analysis of surface waves (SASW), a nondestructive testing method, has mainly been developed and used for many years in the fields of geotechnical engineering and highway engineering, such as for examining the material properties of pavement systems and soil media under an infinite half-space condition. Extensive research in this area has been focused on understanding the applicability and limitations of the SASW method in recent decades. This method consists of generation, measurement, and processing of dispersive surface waves. During an SASW test, the surface of the medium under investigation is subject to an impact to generate surface wave energy at various frequencies. Two vertical accelerometer receivers are set up near the impact source to detect the energy transmitted through the testing media. By recording signals in digitized form using a data acquisition system and processing them, surface wave velocities can be obtained by constructing a dispersion curve. Through forward modeling, the shear wave velocities can also be found, which can be related to various material properties. This paper presents the relationship between the theoretical and experimental compact dispersion curves when the SASW method is applied to multi-layer thin cement mortar slab systems with a finite thickness. The test results of surface wave velocity obtained from the experimental compact dispersion curve are found to have higher values than the results obtained from the theoretical dispersion curve due to different boundary conditions and reflections from the boundaries. An experimental study was conducted to examine if the dispersive characteristics of a Rayleigh wave exist in the multi-layer cement mortar slab systems. This study can be utilized in examining structural elements of general concrete structures and can be applied in the integrity analysis of concrete structures with a finite thickness.     

高温下FRP加固钢筋混凝土板非线性分析

为了给FRP加固钢筋混凝土板的耐火性能研究提供数值计算方法,实现FRP加固板高温下的热-力学耦合分析,在合理选取混凝土、钢筋及FRP材料力学性能参数的基础上,编制了FRP加固板高温下的非线性有限元分析程序,程序的有效性得到了已有试验结果的验证.基于程序对薄涂型防火涂料厚度、载荷比、混凝土板纵筋配筋率、FRP加固量、混凝土板厚及钢筋保护层厚度等对影响加固板跨中位移的相关参数进行计算分析.结果表明:防火涂料厚度、火灾载荷比以及FRP加固量对加固板耐火性能有显著影响;混凝土板厚及钢筋保护层厚度也对火灾下的加固板挠度产生影响;而跨中挠度随混凝土板纵筋配筋率的变化不明显.     

阳光利用下的住宅建筑节能改造设计研究——以重庆地区住宅建筑为例

本文针对重庆地区住宅建筑遮阳设计的现状对一些已建和在建项目进行了实地调研分析,并抽取其中一栋住宅建筑进行了节能改造设计,以期为阳光利用下的建筑遮阳设计研究提供较为充实可靠的资料、为重庆市其它类型建筑的节能改造提供借鉴。     

基于区块链的建筑信息模型图纸多人协同创作系统

建筑信息模型(BIM)图纸多人协同创作在大型建筑项目中很重要,而现有的基于Revit等建模软件或云服务的BIM图纸多人协同创作方法存在BIM图纸版本混乱、不易溯源以及数据安全风险等问题.针对这些问题,设计了一种基于区块链的BIM图纸多人协同创作系统.该系统采用链上链下协同的存储方式,使用区块链和数据库分别存储BIM图纸...