短半径厚壁弯头成型工艺研究

短半径弯头成形变比很大,故采用两次热压方式成形,本文采用新钢种A335P92,介绍了其加工性能并对原来使用的厚壁弯头热压成形工艺提出了改进方法,改进后的厚壁弯头热压成形工艺具有减少模具制造成本、成形操作简单、降低劳动强度和提高成形质量的优点。     

基于LM3S9B92和Zigbee技术的城市轨道施工安全监控系统

以LM3S9B92为核心设计了一种基于Zigbee无线传感器网络的城市轨道施工安全监控系统,可以实现城市轨道施工环境参数监测,人员定位和设备远程控制等功能。根据系统的功能需求和系统构成特点,对系统总体方案、系统硬件设计方案和系统软件设计方案进行了设计和实现。经城市轨道施工环境测试,该系统各个功能模块性能良好,很好的实现了环境监测、人员定位和语音通信,设备的远程控制等功能,达到了预期的设计目标     

UK implementation of agri-environment regulation 2078/92/EEC: enthusiastic supporter or reluctant participant?

This paper discusses the UK response to Agri-environment Regulation 2078/92/EEC, which recognized the need for increased emphasis to be placed on the landscape and environmental value of agriculture. It is argued that the UK has been a reluctant participant in the Regulation and that it has largely failed to put into place an innovative and far-sighted policy package when opportunities were offered in the early 1990s. Four specific reasons are discussed that help explain the reluctance to expand substantially the UK agri-environmental programme. Top-down policy-making structures have hindered the incorporation of ideas from the grassroots level; a predominance of productivist thinking amongst policy makers has reduced the urge for comprehensive, holistic and well-funded agri-environmental schemes; an historically strong emphasis on targeted habitat protection has hampered the introduction of horizontal agri-environmental measures; and the changing role of pressure groups within the agri-environmental policy bargaining process has resulted in policy incrementalism rather than reform. The paper concludes by arguing that state and non-state policy makers in the UK need to rethink their agri-environmental policy approaches if more sustainable and effective policies are to be implemented in the future.     

Legal approval of building innovations in Australia — A key to deliverance from evil for the global village?

Hugh Knox's paper describes accreditation as an essential part of building regulation in Australia. The paper was presented at the CIB Congress in a session entitled 'Building regulations: a necessary evil' but a successful experiment carried out in Australia showed that regulations and standards can deliver significant benefits rather than obstruction. Accreditation can be the catalyst that exorcises the 'evil'.     

基于C(t)积分及参数Ac的P92钢高温蠕变裂纹扩展研究

对于在高温环境下工作的构件,蠕变裂纹扩展是一种主要的失效机制,而裂纹尖端的拘束水平对蠕变裂纹扩展率有很大的影响。通过数值仿真与相关试验数据对比的方法,对裂纹扩展尖端的应力应变率场表征参量C(t)积分进行了相关研究,并基于参数Ac研究了P92材料裂纹尖端的拘束水平对蠕变裂纹扩展的影响。研究结果表明,C(t)积分值随裂纹扩展急剧减小,其数值及变化与积分路径到裂纹尖端的距离相关性很强,并且与拘束水平有一定的关系;拘束水平影响蠕变裂纹扩展率,拘束越大,裂纹扩展速率越快;参数Ac可以有效表征裂纹尖端拘束水平,其在寿命预测方面的应用有待进一步研究,同时在含裂纹的高温工作构件寿命评估方面有重大的意义。     

Development of a polymerase chain reaction assay for detection of three canola transgenes

Many countries are developing or implementing regulatory requirements to monitor for the presence of genetically modified (GM) materials in seeds, grain, and derived food products using DNA and protein-based methods. There is no published report on the detection of different GM transgenes in canola, and this study is aimed at developing qualitative PCR methods for the three major GM transgenes commercially available in canola. Primer sequences were generated from Gen-Bank and previously published information to develop a polymerase chain reaction (PCR) detection method for Roundup Ready (glyphosate tolerance, GT73 event), Liberty Link (glufosinate ammonium tolerance, HCN92 event), and BX (Bromoxynil tolerance, OXY235 event) canola varieties. On using PCR, two primer pairs for each of the GT73 and HCN92 and one primer pair for OXY235 amplified specific amplicons for the three GM transgenes. All three GM transgenes were detected simultaneously by multiplexing the five primer pairs in a single PCR reaction. Multiplexing of the five primer pairs for DNA prepared at 1% (one GM seed in 99 non-GM seeds) and 0.5% (one GM seed in 199 non-GM seeds) levels generated the expected DNA fragments for GT73, HCN92, and OXY235. This information will lay the groundwork for the development of a quantitative PCR assay for canola transgenic events.     

焊接热循环对T92钢组织脆化的影响

采用Gleeble—3800热模拟试验机对T92钢进行不同峰值温度的焊接热循环试验,并对试验试样进行室温冲击韧性试验.借助光学显微镜分析其微观组织,用扫描电镜观察其冲击试样断口形貌特征.结果表明,T92钢焊接加热温度在900℃以上易因奥氏体晶粒粗大导致其组织脆化,断口呈现典型的准解理形貌特征,而在900℃以下的焊接加热仍能保持较好的室温冲击韧性,断口呈现均匀细小的韧窝断口特征;T92钢中高含量的强碳、氮化物形成元素高温状态重新固溶后,在奥氏体中的扩散速度滞后于晶界的迁移速度,进而产生过饱和的室温组织是引起组织脆化的直接原因.     

P92无缝钢管的研制

介绍了研制P92无缝钢管取得的成果和生产工艺特点。对研制的P92无缝钢管进行的高温拉伸性能和高温持久性能等性能评定结果表明:该无缝钢管具有均匀的金相组织,各项力学性能指标和工艺性能完全满足ASME SA 335/SA 335M标准规定和高温锅炉管道使用要求。     

高Cr铁素体耐热钢中的Z相

高Cr铁素体耐热钢是广泛应用于电厂恶劣环境下的新型钢种,在长期服役后的高Cr铁素体耐热钢中发现了Z相。综述了Z相的基本特性和T91、T92、T122钢3种典型的高Cr铁素体耐热钢中Z相的研究进展,概述了Z相对材料性能影响的微观机理,并对未来研究的重点进行了展望。