某地铁旁地下建筑与地铁主体之间的受力分析

为研究坐落在地铁顶板上的建筑的力学行为,对坐落在地铁顶板上的建筑进行有限元分析。根据地铁顶板的最大限值荷载和文克尔地基模型理论采用YJK软件进行有限元分析,推算地铁顶板的刚度,以此作为地下室底板的基床系数设计依据,并使用SAP2 000软件进行对比分析。根据推算地基的基床系数对地下室底板采用YJK软件进行基础设计,同样采用SAP2 000进行对比分析。结果表明：YJK软件得到的基床系数和位移结果与SAP2 000的结果差别不大,YJK软件有限元分析的结果是能够指导设计的,地下室与筏板的最大变形发生在剪力墙的外边缘,其次是直接坐落在地铁顶板上柱子处。     

锚杆支护回采面落山角瓦斯综合处理

回采面上、下落山角采用砌墙隔离、抽放、排放瓦斯等方法综合处理。减少采空区瓦斯涌出 ,消除落山角瓦斯积聚 ,实现安全生产。为两道为锚喷支护的上、下落山角瓦斯处理提供了一定经验。     

能量色散X—荧光谱仪测定黄金饰品

众所周知,黄金饰品具有经济价值和使用价值。为了识别饰品伪真和质量,产生了许多检测方法:火试金法是检验K金含量的标准法,但操作复杂,技术性强和具有破坏性,故把它作为一种仲裁方法。密度法是测定已知杂质含量的黄金成色。虽然它是无损检测,但有一定的技术难度,所以用得较少。用得较多是x—荧光谱法(波长色散x—荧光谱仪和同位素x—荧光仪等等)。但随着科学技术的发展,尤其电脑的发展。波长色散x—荧光谱仪能满足各项分析要求。但该仪器较复杂,价格昂贵以及对周围环境要求较高等等。     

当量粉体体积对自密实混凝土工作性能的影响

主要提出了当量粉体体积的概念,即根据混凝土中各粉体的需水量的不同,以水泥为参照,将各粉体体积均换算为当量水泥的体积。试验发现在用水量以及砂石不变的情况下,新拌自密实混凝土整体工作性能达到最佳的情况下对应有一定的最优当量粉体体积,且当量粉体体积的大小对自密实混凝土的工作性能影响明显。     

交联多元醇在棉及其混纺织物上的快速焙烘

引言在以往的研究中,已经论证了聚乙二醇(PEG)通过交联能粘接在各种基质物上,并由此使它们不溶于水。多元醇溶液(含有交联剂与酸性催化剂)以80%左右的轧液率浸轧在多种不同类型的机织物,然后在70℃烘燥7min,在130℃焙烘2min。这种方法处理的织物,当它们     

高精度固体流量控制系统在塑料厂中的应用

本文给出了自行研制的高精度固体流量控制系统的结构和主要性能，同时给出了在塑料车间投运的参数及应用结论。     

涂料白在仿丝绸印花中的白度和手感研究

针对仿丝绸的生产工艺和风格不同于涤／棉混纺织物，本文对涂料白在仿丝绸印花中的白度和手感进行了研究。认为白度和手感的关键在于粘合剂和地色染料的选用，以及洗涤工艺。     

Fully 3-D PET reconstruction with system matrix derived from point source measurements

The quality of images reconstructed by statistical iterative methods depends on an accurate model of the relationship between image space and projection space through the system matrix The elements of the system matrix for the clinical Hi-Rez scanner were derived by processing the data measured for a point source at different positions in a portion of the field of view. These measured data included axial compression and azimuthal interleaving of adjacent projections. Measured data were corrected for crystal and geometrical efficiency. Then, a whole system matrix was derived by processing the responses in projection space. Such responses included both geometrical and detection physics components of the system matrix. The response was parameterized to correct for point source location and to smooth for projection noise. The model also accounts for axial compression (span) used on the scanner. The forward projector for iterative reconstruction was constructed using the estimated response parameters. This paper extends our previous work to fully three-dimensional. Experimental data were used to compare images reconstructed by the standard iterative reconstruction software and the one modeling the response function. The results showed that the modeling of the response function improves both spatial resolution and noise properties.