共查询到20条相似文献,搜索用时 140 毫秒
2.
3.
4.
5.
基于灰色综合评价方法的制造企业供应商选择 总被引:2,自引:0,他引:2
主要探讨了制造企业供应商评价和选择问题,给出了一种灰色综合评价方法。该方法考虑到信息的灰色性,同时应用了层次分析法的思想,为供应商评价和选择提供了一种较为科学的方法。 相似文献
6.
提出了基于AutoCAD软件的确定复杂形状旋转体拉延毛坯直径的方法-计算机作图查询法,这种方法操作严谨,结果准确,比原有的3种方法简捷、快速,是一种值得推广的好方法。 相似文献
7.
《稀有金属材料与工程》2005,22(2):49-50
表面活性坚强内固定钛接骨板及其制造方法,医用钛及钛合金表面活化改性方法,用石墨电极对钛合金材料表面电火花放电强化处理的方法,一种钛表面辉光离子无氢渗碳工艺方法,一种稀土铝硅钛合金的生产方法。 相似文献
8.
气化模铸造涂料性能的现场检测 总被引:2,自引:1,他引:1
本文给出了气化模铸造涂料性能如密度、固含量、粘度和涂层厚度等几种现场检测方法。指出对于涂料这种非牛顿流体,只用一种检测方法是局限性的;将几种方法配合使用,在现场生产中可获得良好效果。 相似文献
9.
10.
增加叶轮出口宽度是降低离心泵关断点扬程的典型方法。针对600 MW超临界锅炉给水泵关断点扬程过高问题,分别提出4种增加叶轮出口宽度的方式对其进行改型设计。对其中1种改型方案通过试验方法研究,其余3种改型方案采用CFD方法研究。结果表明:采用移动前盖板出口的方法降低关断点扬程的效果最佳,其水力性能参数优于其余3种方法,运行流量为1250 m3/h时,相比于平行移动前盖板方法效率增加1.9%;叶轮出口宽度变化比与扬程变化比在一定范围内满足二次多项式回归关系。在此基础上,拟合出二次多项式方程。 相似文献
11.
12.
铸造法制备纳米碳管增强镁基复合材料的力学性能研究 总被引:4,自引:0,他引:4
在氩气保护下,采用搅拌铸造的方法制成了碳纳米管增强镁基复合材料,测试了力学性能,观察和分析了显微组织.同时,用TEM和EDS方法对碳纳米管涂覆层的界面结构和成分进行了分析.试验结果表明:采用化学镀镍处理,可在CNTs表面获得均匀且结合力较强的涂覆层,改善了与基体的润湿和结合状况.CNTs对镁基材料具有较好的增强效果,经过涂覆处理的CNTs,增强效果更明显.在本试验条件下,CNTs能细化晶粒组织,提高复合材料的抗拉强度、伸长率、硬度和弹性模量. 相似文献
13.
14.
Development of the marks tracking technique for strain field and volume variation measurements 总被引:1,自引:0,他引:1
The mark tracking method is a simple and efficient technique for a local strain measurement. We show the possibilities of the mark tracking for field measurement. We present a procedure which allows us to experimentally characterise this technique depending on the sensor and the marks' dimensions. The method presented is insensitive to illumination variation and to in-plane rotation of the specimen. The strain values are obtained by analysis of four marks. In order to obtain a displacement field, we analyse a series of small groups of spots. With the help of an average of the parameters (using a series of initial images), we suppress the systematic error that we can observe when we use a method comparing an initial state to a deformed one. So the strain uncertainty becomes less that 0.0002 for a local study and 0.002 for a whole field study (measurement base 20×20 pixel2). 相似文献
15.
The yoke method is usually used as a magnetic testing method of welds. In this paper, we study the influences of the air gap between the magnetic pole and the specimen surface on the average magnetic flux density passing through the specimen, and the specimen thickness on the leakage magnetic flux density from a flaw using finite element method (FEM). When the air gap increases the average magnetic flux density at the center of the specimen length decreases. We can estimate the intensity of the magnetic field on the specimen surface by extrapolating the magnetic flux density in space to that at lift-off being zero. Moreover, the maximum leakage magnetic flux density from a flaw decreases with increase in the specimen thickness even if the average magnetic flux density passing through the specimen is the same. 相似文献
16.
17.
Rapid computation of eddy current signals from narrow cracks 总被引:2,自引:0,他引:2
Theodoros Theodoulidis Nikolaos Poulakis Athanasios Dragogias 《NDT & E International》2010,43(1):13-19
An existing boundary element method model for eddy current inspection of ideal or narrow cracks is revised. Using some lately devised concepts on efficiently and rapidly simulating canonical eddy current geometries, we show how this model can be made easier to implement and faster to calculate. The approach is largely based on a novel method for rapidly calculating the Green's function and reducing the matrix fill-time, and also on a similar method for rapidly computing the incident electric field. As a result, the model has been made an order of magnitude faster than the existing one without sacrificing accuracy. We pay attention to numerical analysis details and analyze issues that so far have not been clarified. The validity of our approach is also verified by the experiment. Although we have tested the model against published data, we have also produced our own precision measurements for surface and through-the-thickness slots in plates with the coils performing scans along and across the slots at various frequencies. 相似文献
18.
19.
金属薄膜结合性能的评价方法研究 总被引:1,自引:0,他引:1
针对Al2O3基体上磁控溅射沉积的Au/NiCr/Ta多层金属薄膜,用压痕法、滚动接触疲劳法、摩擦力和声发射两种模式同时监测的划痕法,对比研究了金属薄膜与基体的结合性能。结果表明:压痕试验从压痕形貌上很难判断薄膜与基体是否发生剥离,压入过程中也没有诱发裂纹的产生,更无法分辨薄膜层间的分离;由于金属薄膜的塑性变形,滚动接触疲劳法很难应用于金属薄膜结合性能的表征:划痕法可应用于多层金属薄膜的特异划擦行为研究,其中摩擦力模式能反映压头进入不同金属膜层时的变化,层间声发射信号的灵敏度不如摩擦力信号,对应试验条件,摩擦力曲线存在若干以拐点为特征的载荷,摩擦力曲线上出现的拐点及拐点特征载荷值可以在一定程度上反映多层膜的层数和层厚,并可刻划出该膜/基体系承受压入载荷而不发生剥落的能力。 相似文献