交替注入流动注射分光光度法同时测定铁和铜

以２－（５－溴－２－吡啶偶氮）－５－二乙氨基苯酚（５—Ｂｒ—ＰＡＤＡＰ）为显色剂,乳化剂ＯＰ为增溶剂,乙酸－乙酸钠缓冲液作载液,采用交替注入样品方式,建立了流动注射同时测定铁和铜的新方法．测定频率为６０样／ｈ,铁、铜的线性范围均为０．２—１．８μｇ／ｍＬ．应用于铝合金和人发中铜、铁的测定,结果满意。     

4Cr5MoV1Si热旋压缩口成形旋轮热处理工艺

通过对高压气瓶热旋压缩口成形旋轮的性能要求分析,选择了热作模具钢4Cr5MoV1Si,介绍了4Cr5MoV1Si旋轮热处理工艺。     

Boundary extension for Hilbert-Huang transform inspired by gray prediction model

One of the open problems to which Hilbert-Huang transform (HHT) inevitably confront is end effect, a plague from which many data analysis methods have been suffering from the beginning. Aiming at mitigating end effects of HHT, a boundary extension method is introduced, which is based on the well-known gray prediction model termed as GM(1,1). Using the idea of cubic spline, the calculation of derivative to accumulated generating operation (AGO) series in GM(1,1) model is developed. We further make full use of residual series produced in the GM(1,1) model to achieve better prediction precision. According to numerical experiments on synthetic and real world signals, as well as comparisons of the proposed method with other six generally acknowledged methods, including the original HHT, multiple residual error gray model (MREM), “window frame”, mirror extending (ME), autoregressive (AR) model, and artificial neural network (ANN) based HHT, it is demonstrated that our method significantly reduces end effects and improves decomposition and transformation results of HHT.