D级压力容器制造许可证鉴定评审中企业存在问题综述

阐述了在D级压力容器制造许可证取换证鉴定评审过程中,取换证制造企业存在的较为普遍的问题。     

悬浮液进样-火焰原子吸收光谱法测定茶叶中的微量铬

将茶叶悬浮于琼脂胶体中制成悬浮液 ,直接喷入空气 -乙炔火焰 ,用火焰原子吸收光谱法测定茶叶中的微量铬 ,方法简便、快速、灵敏度和精密度高、测定结果与用灰化法处理样品一致 ,检验表明 ,两种样品前处理方法之间无显著性差异。相对标准偏差为 3.4 %～ 6 .1% ,加标回收率为 95 .7%～ 10 3.8 %。     

Photocross-linking of low-density polyethylene. III. Supermolecular structure studied by SALS

The supermolecular structure of photocross-linked polyethylene (XLPE) has been studied by small-angle light scattering (SALS). The data show that the spherulitic structure of XLPE gradually deteriorates with increasing degree of cross-linking and increasing irradiation temperature from well-developed spherulites to rodlike aggregates and disordered lamellar structures. A photocross-linked sample of PE has lower crystallinity, smaller crystallites, and smaller spherulites than does the original sample. At high degrees of cross-linking, the SALS patterns show little or no spherulitic structure. Results with photocross-linked polyethylene demonstrate that the overall effect of cross-linking on the morphological structure is similar to that of an increase in molecular weight of the polymer. © 1993 John Wiley & Sons, Inc.     

Mathematical model of deoxidization with post stirring in a combined blowing converter

Dissolved oxygen in the steel at the terminal of the converter smelting process is the main cause for the formation of oxide inclusions, and the high terminal oxygen content worsens the steel cleanness. However, post stirring in a combined blowing converter can promote the carbon-oxygen reaction in the liquid steel and reduce the dissolved oxygen content at the terminal of the converter smelting process. Thus, the mathematical model of deoxidization in the post stirring process was obtained, and the rationa...     

电梯零速停靠的RBF神经网络预测算法

针对电梯运行过程中存在爬行距离的问题,提出了基于RBF(Radial Basis Function)神经网络的爬行距离预测模型.将预测的爬行距离增加到电梯速度曲线的匀速段,实现减小或消除爬行距离的目的,从而实现电梯的零速停靠.从电梯运行现场采集大量的原始数据,建立RBF神经网络预测模型,与BP(Back Propagation)预测方法进行仿真比较,结果表明RBF神经网络具有更好的预测效果.给出了应用零速停靠RBF预测算法前后电梯运行的速度曲线,爬行距离减小或消除,电梯的运行时间变短,实现了节能.     

世界溶液丁苯橡胶的主要技术进展

评述了溶液丁苯橡胶的技术现状和主要技术进展。介绍了新型锡锂引发剂和用其制备的溶液丁苯橡胶的性能特点，特别是其突出的滚动阻力特性和在不损失湿牵引性下的优异耐磨性。分析了世界，特别是美国、欧洲和日本的溶液丁苯橡胶的需求现状及发展趋势。     

基于局部45°原则的折线图坐标轴网格生成

坐标轴网格是辅助人们观察统计折线图的重要参考结构.文中研究了有利人们感知直线斜率的坐标轴标签.首先通过一系列用户实验探索折线图中网格局部长宽比对于估计线段斜率这一任务的影响,通过用户估计的倾斜角度与直线真实的倾斜角度的误差大小反映不同实验条件的影响程度.实验得出的结论是适当的网格密度、接近正方形的网格格子局部长宽比有利于准确的斜率估计.基于该实验结论,提出了新的为折线图数据自动生成坐标轴的算法,考虑最大标签、最小标签和间隔步长3个变量,参考前人关于标签简洁性、覆盖性、重叠程度的定义,将正方化的局部长宽比这一因素加入水平和垂直2条坐标轴的标签联合优化之中,该算法能够生成既美观又提高图形感知准确性的坐标轴网格.     

Multifocus image fusion method of Ripplet transform based on cycle spinning

The curvelet transform can represent images at both different scales and different directions. Ripplet transform, as a higher dimensional generalization of the curvelet transform, provides a new tight frame with sparse representation for images with discontinuities along C² curves. However, the ripplet transform is lack of translation invariance, which causes the pseudo-Gibbs phenomenon on the edges of image. In this paper, the cycle spinning method is adopted to suppress the pseudo-Gibbs phenomena in the multifocus image fusion. On the other hand, a modified sum-modified-laplacian rule based on the threshold is proposed to make the decision map to select the ripplet coefficient. Several experiments are executed to compare the presented approach with other methods based on the curvelet, sharp frequency localized contourlet transform and shearlet transform. The experiments demonstrate that the presented fusion algorithm outperforms these image fusion works.