Bi-Pb-Tl三元系相图

用室温、高温X射线衍射及淬火的方法,测定了Bi-Pb-Tl三元系25℃的等温截面及该体系中的相结构。     

Progress in near-field photothermal infra-red microspectroscopy

Near‐field photothermal Fourier transform infra‐red microspectroscopy, which utilizes atomic force microscopy (AFM)‐type temperature sensors, is being developed with the aim of achieving a spatial resolution higher than the diffraction limit. Here we report on a new implementation of the technique. Sensitivity of the technique is assessed by recording infra‐red spectra from small quantities of analytes and thin films. A photothermomechanical approach, which utilizes conventional AFM probes as temperature sensors, is also discussed based on preliminary results. Early indication suggests that the photothermal approach is more sensitive than the thermomechanical one.     

Reconstruction of grains and subgrains from electron backscatter diffraction maps

Electron backscatter diffraction maps are capable of yielding a substantial amount of quantitative information about grains, subgrains and boundaries, and the amount and quality of the data may be substantially increased if the pixels of the map are re‐analysed so as to ‘reconstruct’ complete grains or subgrains. The paper discusses the various methods of grain reconstruction and the use of such methods to obtain microstructural information correlating the parameters of dimension, position, orientation and misorientation, which cannot usually be obtained by other means. Grain reconstruction also reveals the nature, location and contacts of all the triple junctions in the microstructure, and the paper discusses two important examples of how these data may be further analysed using automated routines. Boundary connectivity and the length and direction of likely paths along which grain boundary events such as creep fracture or stress corrosion may occur can readily be determined. The overall alignment of boundaries in deformed metals, with respect to the crystallography and the deformation geometry, may be determined as a function of the length and misorientation of the boundary segments.     

Grain size distribution analysis in polycrystalline LiF thin films by mathematical morphology techniques on AFM images and X-ray diffraction data

The influence of the deposition temperature on the grain size of polycrystalline lithium fluoride (LiF) thin films is studied using a mathematical morphology method. On atomic force microscopy images of the LiF surface, the grain sizes and shapes are determined by applying the watershed technique, together with a shape factor algorithm. Also, the domain size of the film structure, determined by an X-ray diffraction data analysis, is compared and correlated with the mean grain size as a function of the deposition temperature. In both cases a linear increase with temperature and a very good agreement among the two structural parameters (grain and domain size) was found.     

Influence of ceria coatings on growth stresses developed in wüstite scales formed on pure iron at 800°C

In situ XRD stress determinations have been performed during oxidation of pure iron (p(O₂=2 × 10^–3 Pa,T=800°C)). The compressive stress, initially present in the substrate due to surface preparation, is completely released at 400°C. Under the test conditions, the in situ compressive-stress level determined in the FeO scale during oxidation is not strongly dependent upon the presence of a ceria coating. On blank and coated specimens, the compressive stress varies from –400 ± 80 MPa to –150 ± 100 MPa during 30 hr oxidation. The decrease is quicker at the beginning of the test performed on blank specimens. Epitaxial relationships between the wüstite scale and iron (under low-pressure starting conditions) caused thein situ compressive stress in the oxide scale to be two times greater compared to the usual test conditions. This indicates that epitaxial relationships can be a source of stress in an oxide scale that ceria coatings may lower compressive stresses.     

Grinding induced effects in plasma sprayed zirconia coatings

The effect of grinding on the surface layer properties of ceria and yttria partially stabilized zirconia plasma-sprayed coatings (CePSZ, YPSZ, respectively) has been studied by X-ray diffraction methods. For this purpose, the modified model of line broadening analysis has been derived. The model considers elastic anisotropic properties along with more random paracrystal imperfections, both affecting X-ray line broadening. Grinding-induced microstructural changes were also studied using an estimation from the quantitative Orientation Distribution Function (ODF) texture. It was concluded, based on this work, that CePSZ ceramic is less mechanically stable compared to YPSZ. Consequently, more beneficial mechanical properties of a ground surface layer can be expected for CePSZ plasma-sprayed coatings.     

黄土构造节理型地裂缝的地球物理勘探

采用地球物理勘探中的地震绕射波方法、高密度电法和地质雷达3种方法对黄土构造节理型地裂缝进行了探测尝试。结果表明,这些手段对探测黄土构造节理型地裂缝是有效的,地震绕射波方法可给出地裂缝的位置、深度等参数;高密度电法方法不仅可以给出其位置,还可得到其宽度参数;而地质雷达的探测结果可给出近地表数m内地裂缝(盲沟)的高精度图像,更适合探测隐伏地裂缝。     

非规则几何槽形光栅衍射效率自动计算方法

为了快速地自动计算非规则几何槽形光栅的衍射效率,使用MatLab软件模拟各种槽形,自动获取槽形参数,并根据这些槽形参数运用严格耦合波分析方法,计算光栅的衍射效率。结果表明所设计的计算程序能够快速自动分析非规则几何槽形并计算其衍射效率。该方法可用于循环计算槽形逐渐变化过程中的衍射效率。     

承压设备的超声检测技术

系统介绍了承压设备的超声检测技术的发展概况。较全面地展示了传统超声检测技术的应用领域,综述了超声衍射时差技术、空气耦合技术和超声导波技术等超声检测新技术的最新研究成果。最后,讨论了承压设备的超声检测技术的发展方向。