The effect of prior austenite grain size on the transformation behaviour of C-Mn-Ni weld metal

The influence of prior austenite grain size on the transformation behaviour and microstructural development of C-Mn-Ni weld metals was investigated. It was found that increasing the grain size depressed the start temperature of grain-boundary ferrite and slightly increased the acicular ferrite start temperature. The microstructural products also changed from a boundary-dominated effect in the small grain sizes, to an intragranular-dominated effect in the large grain sizes, and at the same time, the morphology of the acicular ferrite was seen to change to a larger aspect ratio.     

Experimental Study on Energy Consumption of Combined Conventional and Dehumidification Drying

Conventional drying, dehumidification drying, and combined conventional-dehumidification drying of wood were experimentally studied in this article. The results showed that the energy consumption in the dehumidification drying is the least but its drying time is the longest. The energy consumption in the combined drying is more than that in the dehumidification drying but less than that in the conventional drying, and the drying time is half of that in the dehumidification drying. The advantages of the combined conventional and dehumidification drying are discussed from the experiments results.     

气体灭火自动控制装置的设计原理

通过科研成果转化的气体灭火系统目前己成为我所科技产业中的主导产品。其控制装置是其中关键配套设备。本文就其开发设计中的设计思想、技术原理、技术设计特色等作一阐述     

浅谈由建筑施工引发的结构设计问题

介绍了建筑施工中引起的几个质量问题，针对出现的问题从结构设计方面提出了修改意见和加强措施。     

蓝山会所

错落有致的几何形窗口的墙面,可以看到窗外斑驳的树影正和窗内淡蓝色玻璃长台上的枯枝相呼应。阳光一天的挪移都能透过几何窗在室内留下足迹。同时窗外的树枝、风、云……大自然的一切身影都被定格成立体而丰富的"壁画",内外空间被无声地融合在一起。相互渗透,瞬息万变除了自然的丰富变化,透过空间设计手法,材料的丰富性使得室内风格更加立体而融洽。清水混凝土,钢板的天花,收纳管线的钢梁和烧毛面的花岗岩地面,营造了一种素面朝天的影像。中度抛光的石材柱子,透明的塑料椅子,淡绿色玻璃发光的长台,不但增强了光线的明暗效果,而且渗透着不张扬的现代感。材料的多样性增添了空间的层次感,光影变化在不同材料上反应出来的不同效果使空间有了更强     

Air entrainment in fresh concrete with PFA

The results of a study into the influence of PFA on air entrainment in fresh concrete are discussed It is shown that the required dosage of AEA to produce an air content of 5.5 ± 0.5% in a PFA modified concrete mix is two-six times that required in the corresponding neat OPC concrete mix. The dosage of a vinsol based air entraining agent (AEA) required appears to be directly related to the PFA content of the mix. Similar direct relationships were obtained with a range of different PFAs. The dosage of an AEA based on the salt of a fatty acid appears to be sensitive to both PFA and OPC contents. For the type of PFA used, the variability of measured air content or the amount of air retained after continued agitation both indicated that vinsol based AEAs show the highest variability whilst fatty acid based AEAs show low variability. The between batch variability of air content was significantly improved by the addition of PFA regardless of the AEA used.     

A novel methanol-tolerant Ir-Se chalcogenide electrocatalyst for oyxgen reduction

A novel methanol-tolerant oxygen-reduction catalyst, Iridium-selenium (Ir-Se) chalcogenide, was synthesized by chemical precipitation in an organic solvent. Auger electron spectroscopy (AES) analysis confirmed that the synthesized Ir-Se chalcogenide had a chemical formula of Ir₄Se. This chalcogenide showed strong catalytic activity towards the oxygen reduction reaction (ORR) and a high methanol tolerance. It was found that most of the oxygen could be directly reduced to water through a four-electron pathway with less than 10% hydrogen peroxide (H₂O₂) being produced during the ORR. The improvement in catalytic activity of the Ir-Se chalcogenide in comparison with that of pure Ir might be attributed to the effect of a bimetallic interaction.     

As,Sb,Sn对30CrMnSiA钢力学性能的影响

在３０ＣｒＭｎＳｉＡ钢中加入不同量的Ａｓ，Ｓｂ，Ｓｎ元素，研究了这些元素单独存在及复合存在时对钢的强度，塑性，冲击韧度及韧脆转变温度的影响规律，并用扫描电镜及俄歇能谱分析了Ａｓ，Ｓｂ，Ｓｎ导致晶界脆化的机理。