Hot Deformation Behavior of a New Nuclear Use Reduced Activation Ferritic/Martensitic Steel

The hot deformation behavior and workability of a new reduced activation ferritic/martensitic steel named SIMP steel for accelerator-driven system were studied.The flow curve and its microstructure were studied at 900-1200℃ and strain rate range of 0.001-10 s~(-1).The results showed that the deformation behavior of the SIMP steel during hot compression could be manifested by the Zener-Hollomon parameter in an exponent-type equation.Based on the obtained constitutive equation,the calculated flow stresses were in agreement with the experimentally measured ones,and the average activity energies QDRV and QHW for the initiation of dynamic recrystallization and the peak strain were calculated to be 476.1 kJ/mol and 462.7 kJ/mol,respectively.Furthermore,based on the processing maps and microstructure evolution,the optimum processing condition for the SIMP steel was determined to be 1050-1200 ℃/0.001-0.1 s~(-1).     

Hot Deformation Behavior and Processing Map of a Cu-Bearing 2205 Duplex Stainless Steel

The hot deformation behavior and processing map of Cu-bearing 2205 duplex stainless steel(2205-Cu DSS) were investigated at temperatures of 950-1150℃and strain rates of 0.01-10 s~(-1).The effects of Cu addition and different deformation parameters on deformation behavior were,respectively,characterized by analyzing flow curves,constitutive equations and microstructures.The results indicated that the shapes of flow curves strongly depended on the volume fraction of two phases.When deformed at low strain rate,DRV in ferrite was prompted with increase in the temperature and was further developed to continuous DRX.At high strain rate,flow localization preferentially occurred in ferrite at low deformation temperature due to the strain partitioning and relatively less fraction of ferrite.The activation energy for 2205-Cu DSS was 452 kJ/mol and was found to connect with the variation of strain,strain rate and deformation temperature.The optimum hot deformation parameters for 2205-Cu DSS were obtained in the temperature range of 1100-1150℃and strain rate range of 0.1-1 s~(-1)with a peak power dissipation efficiency of 41%.Flow localization was the main way to lead to flow instability.Meanwhile,the Cu-rich precipitates were generated within a few ferrite grains when deformed at temperature lower than 1000℃.The interaction between dislocations and Cu-rich precipitates at high strain rate,as well as the limited DRV in ferrite and DRX in austenite,contributed to the complex microstructure and flow behavior.     

基于2 维非负矩阵分解的时频图像压缩在柴油机故障诊断中的应用

针对1 维非负矩阵分解技术对2 维矩阵特征降维时,会产生数据量巨大、计算效率低下和丢失原始数据 结构信息的问题,引入2 维非负矩阵分解技术。通过S 变换得到振动信号的时频图像,用1DNMF 和2DNMF 分别 压缩时频图像,对压缩后的图像信息进行分类,对柴油机在8 种状态下的振动信号进行采集,并采用最近邻分类器、 朴素贝叶斯分类器和支持向量机分类器进行实验对比。结果表明,2 维非负矩阵分解技术比原始的1 维技术计算效 率更高,故障诊断更精准。     

38MnVTi非调质钢的高温热压缩变形特性及加工图

采用Gleeble-1500D型热模拟试验机对38MnVTi非调质钢进行热压缩试验,研究了其在950~1 200℃和应变速率为0.01~10s-1条件下的热变形行为,基于Parasd和Murty两种失稳判据分别建立了动态材料模型(DMM)的加工图,利用加工图确定了试验钢在应变为0.8下的流变失稳区,并分析了两种加工图的差别。结果表明:两种加工图中失稳区域的面积大小相近,功率耗散系数的数值变化趋势相似,但它们的失稳区位置有差异;低的功率耗散系数可以作为一种识别热变形失稳的方法,应避免试验钢在高应变速率下进行大应变量变形;试验钢的热变形最佳工艺参数为变形温度1 050~1 200℃、应变速率0.04~1s-1。     

Feature Extraction and Recognition for Rolling Element Bearing Fault Utilizing Short-Time Fourier Transform and Non-negative Matrix Factorization

Due to the non-stationary characteristics of vibration signals acquired from rolling element bearing fault, the time-frequency analysis is often applied to describe the local information of these unstable signals smartly. However, it is difficult to classify the high dimensional feature matrix directly because of too large dimensions for many classifiers. This paper combines the concepts of time-frequency distribution(TFD) with non-negative matrix factorization(NMF), and proposes a novel TFD matrix factorization method to enhance representation and identification of bearing fault. Throughout this method, the TFD of a vibration signal is firstly accomplished to describe the localized faults with short-time Fourier transform(STFT). Then, the supervised NMF mapping is adopted to extract the fault features from TFD. Meanwhile, the fault samples can be clustered and recognized automatically by using the clustering property of NMF. The proposed method takes advantages of the NMF in the parts-based representation and the adaptive clustering. The localized fault features of interest can be extracted as well. To evaluate the performance of the proposed method, the 9 kinds of the bearing fault on a test bench is performed. The proposed method can effectively identify the fault severity and different fault types. Moreover, in comparison with the artificial neural network(ANN), NMF yields 99.3% mean accuracy which is much superior to ANN. This research presents a simple and practical resolution for the fault diagnosis problem of rolling element bearing in high dimensional feature space.     

安第斯成矿带铜多金属成矿特征专题图设计与编制

积极开展多渠道的全球地质矿产资料产品开发与信息服务,对贯彻落实我国“走出去”政策,充分利用“两种资源、两个市场”,提升全球地质矿产数据库信息服务能力,为“走出去”企事业单位提供基础性地质矿产资料具有重要的意义。安第斯成矿带铜多金属成矿特征专题图件的编制,是中国地质调查局发展研究中心为矿业企业提供定制服务的一次重要尝试,也是全球地质矿产信息系统面向社会化应用的重要体现。通过对安第斯成矿带地质、构造和铜多金属矿产数据资料的分析与整理,基于现代空间数据库与地理信息技术,设计编制了厄瓜多尔、玻利维亚、智利、阿根廷及安第斯成矿带的地质与铜矿分布情况系列专题图,建立了铜矿数据库,为铜多金属成矿特征分析提供了详实数据资料和成果图件。结合工作实际,重点阐述专题地图设计思路、数据处理过程和专题成果。     

纸质地图的作用及对策研究

纸质地图作为人们出行的助手,受到电子地图越来越多的冲击,有人质疑纸质地图即将被电子地图所取代。本文结合纸质地图和电子地图的优劣对比,阐述了纸质地图在现代社会生活中应该发挥的作用,强调了其在辅助出行、普及地理知识、军事价值、专题图应用和文史价值方面的意义。同时结合工作实践重点介绍了纸质地图面临冲击所采取的应对措施。     

基于AutoLISP的地形图数学精度检测算法的设计与实现

介绍了测绘产品质量监督检验工作中对数字地形图产品数学精度检测的一种算法。该算法通过遍历展绘的检测点坐标,依次定位显示检测点视图窗口,然后采用人机交互操作方式实现地形图数学精度的快速检测统计与评分。文章结合地形图产品质量检验项目,以LISP语言为例,对算法的基本设计思路进行了说明与实现。最后通过工程实例对程序的实用性和有效性进行了测试,达到了预期结果。     

从三维模型到三维数字地图的突破——解读浙江省《三维数字地图技术规范》

三维数字产品已成为基础地理信息数据的重要组成部分,从三维模型到三维数字地图是个重大突破。本文简述了浙江省《三维数字地图技术规范》(DB33/T934-2014)的内容,分析了该标准与国家行业标准的关系以及在模型分类和编码、地图分幅和编号、比例尺、数学基础、精度和表达等方面的创新点。在实施时宜结合实际,选择产品的类型,制定相应的技术指标。     

城市地震应急避难场所地图集的设计与编制

地震应急避难场所地图集是地震系列专题地图中最常见、应用最广泛的一种,在城市应急保障方面发挥着重要的作用。本文从地震应急避难场所的功能出发,探讨了应急避难场所地图集的设计和编制方法,并以福州市为例进行了实验和应用,为今后的城市应急避难专题图编制提供参考。