共查询到20条相似文献,搜索用时 78 毫秒
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高宏星 《现代测量与实验室管理》2005,13(1):37-38,12
本文介绍了依据JJF1059—1999《测量不确定度评定与表示》的要求,按照GB/T7314—1989《金属压缩试验方法》中的办法,对金属材料抗压强度σbc进行测量,并对其测量结果的不确定度评定的方法。通过评定得出金属材料抗压强度σbc测量结果的扩展不确定度。 相似文献
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胡江桥 《中国新技术新产品》2013,(20)
本文介绍了金属材料成分分析的发展背景,并分析金属材料成分分析重要性,然后详细介绍金属成分分析的传统方法和新方法,并根据金属材料分析方法发展现状分析其发展趋势,最后对全文进行总结分析。 相似文献
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本文介绍了依据JJF10 5 9- 1999《测量不确定度评定与表示》的要求 ,按照GB/T7314 - 1989《金属压缩试验方法》中的办法 ,对金属材料抗压强度σbc进行测量 ,并对其测量结果的不确定度评定的方法。通过评定得出金属材料抗压强度σbc测量结果的扩展不确定度。 相似文献
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测量不确定度原理及在理化检验中的应用第一讲测量不确定度的基本概念及A类标准不确定度 总被引:10,自引:8,他引:2
王承忠 《理化检验(物理分册)》2003,39(1):57-60
介绍了测量不确定度原理及在理化检验中的应用。就不确定度的定义、分类、评定步骤和方法、报告与表示、有效位数等问题进行了讨论。并对金属材料拉伸试验结果测量不确定度作了详细评定,以作为在理化检验中应用的一个实例。 相似文献
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安永成 《技术监督实用技术》1997,(3)
市场上销售的74厘米(29英寸)彩电对角线的实际屏幕尺寸只有68厘米(27英寸),64厘米(25英时)彩电对角线的实际屏幕尺寸只有59厘米(23英寸),54厘米(21英寸)彩电对角线的实际尺寸只有51厘米(20英寸)。彩电名义尺寸与屏幕有效画面尺寸不同的原因是彩色显像管型号的不同命名法造成的。我国彩色显像管尺寸按彩管对角线最大外形尺寸标注,包括了玻壳尺寸,而不是按有效屏幕对角线实际尺寸标定。现将国际彩管型号命名法和国内彩管型号命名法介绍给大家,供参考。国际统一命名法:①字母②数字③字母④数字⑤字母④数字。第①部分:用一个字母、表示彩管用途,如电视用彩管用A表示,监示器用彩管用M表示,宽屏幕彩管用W表示。第②部分:二个数字表示荧光屏最小有效屏幕画面对角线尺寸,以cm计量。四舍五入取整数。第③部分:用三个字母(不使用I和O)组成。表示种类特征。其中第一个字母表示国别,后面按拉丁文顺序排列。第④部分:由二个数字表示某个系列管中的特定顺序号,单色管由一个数字组成。第⑤部分:采用字母表示荧光膜用荧光粉特性。对彩色电视机用彩色管,荧光粉用单一字母X表示。对黑白管用荧光粉 相似文献
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文章主要介绍了计算机在金属材料教学中的应用,重点介绍了《金属材料咨询系统》、《金属塑性加工学》CAI、《挤压模具CAD优化设计》三大软件,指出了利用现代教育技术改革教育方法的必要性和重要性。 相似文献
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李维铖 《理化检验(物理分册)》2000,36(9):424-1984
各种硬度试验方法标准修订多年之后 ,目前各种硬度值的表示方法尚有不符合标准的写法 ,现介绍几种硬度值的表示方法。1 布氏硬度值的表示方法GB2 31 - 1 984《金属布氏硬度试验方法》标准中规定 :(1 )压头为钢球时 ,布氏硬度符号用 HBS表示 ,适用于布氏硬度值在 450以下的金属材料。(2 )压头为硬质合金球时 ,布氏硬度符号用HBW表示 ,适用于布氏硬度值在 650以下的金属材料。(3)布氏硬度值在 350~ 450范围内 ,用钢球或硬质合金球均可。(4)符号 HBS或 HBW之前的数值为硬度值 ,符号后面按球体直径、试验力和试验力保持时间的顺序 ,用数… 相似文献
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傅志强 《现代测量与实验室管理》2003,11(2):31-32,34
本文根据JJF1059-1999《测量不确定度评定与表示》的要求,对GB/T228-2002《金属材料室温拉伸试验方法》中抗拉强度Rm测量结果的不确定度进行了评定。 相似文献
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金属材料科学发展的历程与人类思维方式的演变 总被引:1,自引:1,他引:0
纵览了人类思维方式的演变、自然科学和金属材料科学发展的历史,阐述了金属材料及其理论的层次性和相关性。介绍了我们为实现金属材料科学设计的规划轮廓。 相似文献
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测量不确定度直接评定法和综合评定法的几个典型实例第一讲直接评定法及其实例 总被引:1,自引:0,他引:1
王承忠 《理化检验(物理分册)》2006,42(4):210-215
采用直接评定法评定了带肋钢筋拉伸性能、金属材料维氏硬度检测结果的测量不确定度,用综合评定法评定了金属材料夏比缺口冲击试验、洛氏硬度检测结果的不确定度。结果表明,综合评定法在这些典型实例中解决了金属材料理化检测结果测量不确定度评定的某些难点。 相似文献
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Currently, dental bleaching and fluoride treatment agents are popular for esthetic purposes and prevention of plaque and caries formation. The corrosive effect of these agents on dental metallic materials has not been well documented. It was an objective of this in vitro study to evaluate and compare chemical and electrochemical corrosion behavior of seven metallic dental materials in commercially available fluoride and bleaching agents. Fluoride treatment agents were tested on Ti–6Al–4V and 17-4 stainless steel. Discoloration on these alloys was examined by a colorimeter and the naked eyes. Bleaching agents were tested on commercially pure titanium, Ni–Co–Mo alloy, type IV gold alloy, and amalgam. Electrochemical corrosion tests were also conducted for these materials, using each treatment agent as an electrolyte. All tested materials suffered from discoloration, which mostly disappeared after brushing. The fluoride-treated 17-4 stainless steel indicated severe intergranular attack, causing localized Cr depletion. The bleaching agents made the passivation layer on the metallic materials unstable. Within the limitations of this study, although these treatments are indicated for patients (enamel), it is proven that these agents are contraindicated for dental metallic materials. 相似文献
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Surfaces of various kinds of metallic materials spheres were treated by nanocrystalline surface severe plastic deformation and then pulsed nanocrystalline plasma electrolytic carburizing to study nanocrystalline substrate effect on formation and nano-hardness of hard nanocrystalline layer. The surface layers of the metallic materials developed by the nanocrystalline surface severe plastic deformation were characterized by means of high resolution scanning electron microscope. Nearly equiaxed nanocrystals with grain sizes ranging from 15 to 90 nm were observed in the near surface regions of all metallic materials, which are low carbon steel and commercially pure titanium. The effect of substrate nanocrystallization on growth kinetics and hardness of formed nanocrystalline carbide layer was studied with the means of figure analysis and nanohardness tests. Figure analysis show the length to diameter ratio and distribution curve of nanocrystals and it has been found that the achieved properties of hard layer (growth rate, nano-hardness, nanostructure...) are related to these factors. It was also clarified that these techniques and surface nanocrystallization can be easily achieved in most of metallic materials. Results indicate that the resultant hardened carburized layers exhibited excellent hardness profile. Investigation of the layer characteristics showed strong dependence followed from the treatment experimental parameters as well as the shape of nanocrystals. 相似文献
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Complex stamping operations are becoming widespread in the automotive industry to produce vehicle body parts with adequate mechanical strength and reduced wall thickness. The need for weight reduction drives the development of new metallic materials capable of achieving a good balance between formability and mechanical properties. Advanced high strength steels play a major role in this scenario. The aim of this work was to develop a materials selection strategy for hot stamped automotive body parts using the Ashby approach. The selection process was based on the formability of metallic alloys derived from two fundamentals materials properties, the strain hardening exponent and the stacking fault energy. 相似文献