碳钢与不锈钢表面高浓度渗铬法

在氩气气氛下，应用固体渗铬填料法对碳钢、不锈钢作了表面高铬浓度的渗铬处理，探讨了渗铬温度、时间和渗铬组分对渗层表面铬含量、厚度，试样增重和物相组分影响，碳钢、不锈钢的表面渗铬浓度分别达８０－９４ｗｔ％和７０－８２ｗｔ％。     

冷却速度对激光相变组织分布的影响

提出通过改变边界换热条件，从而改变冷却速度，达到控制激光相变硬化。实验和计算结果的比较表明，这种控制相变及其组织分布的方法能够处理激光淬火难以解决的问题。     

Comments on “A Petri net model for temporal knowledgerepresentation and reasoning”

Yao (1994) has presented a unified time Petri net model (TPN) for temporal knowledge representation and reasoning, where the TPN model presented has a good contribution to the aspect of temporal knowledge representation and reasoning. However, there are a number of errors which should be corrected. The purpose of the paper is to identify these errors, and the corrections provided permit the readers who have been confused by the errors to gain a better understanding of the good ideas presented.     

Precipitation behavior of σ phase in fusion zone of dissimilar stainless steel welds during multi-pass GTAW process

The purpose of this study is to investigate the precipitation characteristics of σ phase in the fusion zone of stainless steel welds at various welding passes during a tungsten are welding (GTAW) process. The morphology, quantity, and chemical composition of the δ-ferrite and σ phase were analyzed using optical microscopy (OM), a ferritscope (FS), a X-ray diffractometer (XRD), scanning electron microscopy (SEM), an electron probe micro-analyzer (EPMA), and a wavelength dispersive spectrometer (WDS), respectively. Massive δ-ferrite was observed in the fusion zone of the first pass welds during welding of dissimilar stainless steels. The σ phase precipitated at the inner δ-ferrite particles and decreased δ-ferrite content during the third pass welding. The σ and δ phases can be stabilized by Si element, which promoted the phase transformation of σ→ϱ+λ₂ in the fusion zone of the third pass welds. It was found that the σ phase was a Fe−Cr−Si intermetallic compound found in the fusion zone of the third pass welds during multi-pass welding.     

厦门市供水产销差率控制分析

供水管网产销差率是反映供水企业管理水平和运行效益的重要指标.介绍了供水产销差率的定义和分类,结合厦门水务集团近几年供水产销差率现状,分析了控制产销差率措施的效果.     

丙酮酸乙酯合成新工艺

以叔丁基过氧化氢(TBHP)为氧化剂,四丁基溴化铵(TBAB)为相转移催化剂,有效地将乳酸乙酯氧化合成丙酮酸乙酯,产品纯度达98% 以上.该反应操作简单,无污染, 为丙酮酸乙酯合成开辟了新方向.     

离子液体催化C_5馏分中二烯烃的聚合反应

合成了多种基于1-丁基-3-甲基咪唑阳离子的离子液体,并作为裂解C5馏分中混合二烯烃聚合反应的介质。考察了离子液体种类、反应温度、反应时间和添加Lew is酸对混合二烯烃聚合反应的影响。实验结果表明,以硝酸根为阴离子的离子液体对混合二烯烃的聚合反应具有一定的阻聚作用;以六氟磷酸根为阴离子的离子液体能明显促进混合二烯烃的聚合反应,提高二聚物的含量;添加Lew is酸(质量分数为1%的ZnCl2)的离子液体对混合二烯烃的聚合反应具有更明显的促进作用,其效果仅次于酸性氯铝酸类离子液体,反应温度以30℃以下为宜,温度过高将促使二聚物进一步聚合,形成三聚物乃至多聚物,降低二聚物的含量。     

PDC钻头在胜利油田深井钻井中的应用

胜利油田为提高深井钻井速度，试验应用了PDC钻头，结果表明，深井钻井应用PDC钻头可大幅度提高机械钻速，缩短建井周期，降低钻井成本，经济效益明显。通过大量的现场试验，扩大了PDC钻头在胜利油田的使用范围，并取得很好的效果，初步形成了PDC钻头推广应用区域模式。详细介绍了胜利油田不适用PDC钻头钻进的地层岩性，给出了钻头选型及钻井参数选择原则，并对应用效果进行了分析。     

小水电CDM项目在西部的开发现状及其优势

介绍国内小水电CDM项目开发现状，分析我国西部丰富的小水电资源分布及开发小水电CDM项目存在的潜力及优势，并提出在开发小水电CDM项目过程中应注意的有关问题。图2幅，表1个。