Ka 波段紧缩场天线的设计

设计了一个Ka 波段紧缩场天线。馈源设计结合角锥喇叭在反射面边缘照射电平下降快与波纹喇叭波瓣宽度宽的特点,通过给角锥喇叭加扼流套的改进设计来实现对反射面的照射。反射面采用锯齿型边缘来降低边缘的绕射作用,并进一步在无法加工锯齿部位贴附三角形吸波材料来减小绕射对静区特性的影响。暗室内采用平面测量结果表明,Ka 波段紧缩场天线静区特性满足设计指标要求。     

Controlled telescopic reinforcement system of fabric-cement composites — Durability concerns

The study objective was to modify the microstructure of AR glass strand to induce a controlled mode of telescopic bonding during service life, by using sub-micron particles absorbed between the filaments of the strand. Two groups of fillers were used: (i) pozzolanic fillers (silica fume) with 50 nm and 200 nm particle sizes; and (ii) polymeric fillers (polystyrene-based polymers), with two glass transition temperatures (− 6 °C and 100 °C). Composites were prepared using fabric reinforcement and tested for tensile behavior. Composite properties could be controlled by addition of fillers into the glass bundle, and the magnitude and efficiency of the modification was highly dependent on the filler type, structure, and properties. The best performance was obtained with silica fume fillers having relatively large 200 nm particles.     

Physico-chemical investigation of clayey/cement-based materials interaction in the context of geological waste disposal: Experimental approach and results

Within the concepts under study for the geological disposal of intermediate-level long-lived waste, cement-based materials are considered as candidate materials. The clayey surrounding rock and the cement-based material being considered differ greatly in their porewater composition. Experiments are conducted on the diffusion of solutes constituting those porewaters in a confined clay/cement composite system using cells. The test temperature was set at 25 °C and 2, 6 and 12 months. Results supply new information: carbonation is low and not clog the interface. Such absence of carbonation allows for the diffusion of aqueous species and, thus, for the degradation of the cement paste and the illitisation of illite/smectite interstratifications. The cement material is subjected to a decalcification: portlandite dissolution and a CaO/SiO₂ reduction in the calcium silicate hydrate. The sulphate in diffusion induces non-destructive ettringite precipitation in the largest pores. After 12 months, about 800 µm of cement material is concerned by decalcification.     

基于MGIS阵地选择模型研究

针对实际作战需要,提出一种方便实用的阵地选择模型,并重点介绍了基于军事地理信息系统的模型求解。该模型通过分析影响阵地选择的主要因素,结合层次分析法确定各因素权值所需要满足的条件,以此构造选择因素的指标评价系统。利用军事地理信息系统对选择因素指标量化分级,设计不同因素缓冲区,以实现数据分析与查询、图层控制等可视化操作获取最佳阵地。实验结果表明,该方法可直观获得符合要求的阵地,较好地实现了最优阵地选择。     

城市微气候国际(地区)合作研究的进展与展望

本文介绍了华南理工大学建筑节能研究中心在多项科研项目的支撑下,与海内外学者共同开展的我国湿热地区城市微气候调节、评估与设计方面的研究进展及阶段性成果,阐明了国际(地区)合作在项目执行过程中所起的作用,对湿热地区城市微气候研究做下一步展望。     

溪洛渡电站地下厂房爆破损伤范围及判据研究

通过现场爆破振动测试和数值模拟方法研究地下厂房爆破损伤范围及判据;在应用FLAC3D数值模拟软件中,损伤变量D被引入弹塑性本构模型,同时将简化的三角形荷载作为爆破冲击荷载施加在炮孔孔壁上,并根据岩石中有效应力确定爆破损伤范围。调整同时起爆炮孔数目,改变单段起爆药量,研究爆破损伤范围与单段药量的关系,结果表明:损伤深度和损伤水平半径均随单段药量的增加而增大,损伤范围随着炮孔深度增加而减小,爆破损伤最大水平半径出现在炮孔顶部面上。根据爆破近区质点速度衰减规律,并通过数据拟合得到对应于不同单段起爆药量的最大损伤水平半径和相应部位爆破质点临界损伤振动速度的关系,临界损伤振动速度可作为爆破损伤安全判据。研究成果有效地应用到实践中,对类似开挖爆破工程具有一定指导意义。     

外墙外保温防火隔离带用保温材料

文章介绍了外墙保温防火现状和防火隔离带用适宜保温材料,并进行了性能比较,重点阐述了防水型蒸压轻质加气混凝土板（FLC板）用于防火隔离带的优势和安装方式。     

精密超白太阳能玻璃退火窑

阐述了超白太阳能玻璃生产退火窑温度制度的重要性,对退火窑的热工控制及退火窑的密封保温进行了详细说明。     

城市增长边界的性质及划定方法探讨——杭州市生态带保护与控制规划实践

随着我国城市化进程加速推进,城市增长与土地资源和生态环境保护等矛盾已日益凸显。划定城市增长边界(UGB)是协调建设与生态保护的有效手段。结合杭州生态带规划案例,对城市增长边界的性质进行辨析,提出刚性UGB与弹性UGB的区别。运用生态敏感性分析、景观生态安全格局构建和建设用地规划等方法,以及面对建设与保护冲突的规划决策方法,探讨了UGB的划定方法,并指出UGB在我国规划应用中需要进一步完善的方面。     

挤压破碎带原位岩体高压渗透变形试验方法

某大型水电工程重力坝坝基为发育规模较大的挤压破碎带,为准确了解挤压带的渗透变形特性,现场模拟电站建成后的水力条件,采用原位高压渗透变形试验,研究挤压破碎带岩体渗透变形破坏形式和程度,确定挤压带的渗透坡降(临界坡降、破坏坡降)及破坏类型。