共查询到20条相似文献,搜索用时 104 毫秒
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《质量探索》2007,(4):5-5
1.大米2.小麦粉3.糖(白糖、精果、果冻) 4.派类食品5.低温肉制品6.农用塑料大棚膜7.果汁类饮料8.黄酒9.皮衣10.t车1 1.液体洗涤剂1 2.笔(铅笔、自来水笔、回珠笔、记号笔) 1 3.炊具(电饭锅、压力锅、不粘锅) 14.家用燃气灶具15.真丝绸面料16.针织品(内衣袜子) 17.裤子1日.羊绒大衣19.黄金首饰20.乒乓球运动器材21.保险柜/箱22.程控文换机23‘铿离子充电电池24.大中型客车25.汽车玻璃26.铝合金车轮27.全钢子午线轮胎28.实木复合地板29.文联聚乙烯电力电缆30.钢丝绳31.磁性材料32.铝合金建筑型材33硬质合金34.高纯阴极铜35.人造金刚石36.税控… 相似文献
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人体是由多种元素构成.其中微量元素占人体总重量的0.005%.微量元素包括七十种元素.其中有14种是人体必须的微量元素.包括有铁、锌、碘,铜、氟.虽然这些微量元素的含量各不相同.在人体内极少.却与人体生命活动息息相关并是不可缺少的元素.它们参与人体的多种机体代谢活动,除促进人体生命活动的微量元素外.在微量元素里还存在一小都分对人体有害的微量元素.它们分别是铅.汞.锻.铋.锑、镉这些微量元素会损害人体神经. 相似文献
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刘寿荣 《理化检验(物理分册)》2010,(7):427-431
在推证了铁磁材料的饱和磁化强度MS或饱和磁极化强度JS和磁饱和状态下的磁感应强度BS间的定量关系的基础上,得到了WC-Co(Ni,Fe)硬质合金的MS,BS和JS分别与合金密度ρ的比值即标称比磁饱和(通称"磁饱和")间的数值换算关系为:BS/ρ(T.m3.kg-1)=JS/ρ(T.m3.kg-1)=μ0.MS/ρ(A.m2.kg-1)=μ0σ(A.m2.kg-1),JS/ρ(4π×10-7T.m3.kg-1)=σ(4π×10-7T.m3.kg-1)=MS/ρ(A.m2.kg-1)=σ(A.m2.kg-1),BS/ρ(×10-7T.m3.kg-1)=4πσ(×10-7T.m3.kg-1)=4π.MS/ρ(A.m2.kg-1)=4πσ(A.m2.kg-1)。因此,采用σ(A.m2.kg-1,4π×10-7T.m3.kg-1)和4πσ(×10-7T.m3.kg-1,A.m2.kg-1)作为比磁饱和的标记和单位并恪守上述各磁学量的换算关系,能确保其中σ的绝对值与单位质量合金的磁矩值一致,并能对比磁饱和数值进行有效的评估和对比。 相似文献
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Ken Russell 《工业设计》2008,(5):64-64
钢材强度高,有延展性.价格也便宜.这使它成为一种很重要的材料.不幸的是.在潮湿的空气中.普通钢材易生锈并且会不断地生锈。在钢材中加入不少于12%的铬后.它就再不生锈.但其价格更加昂贵.多年后美国钢铁业发现.在普碳钢中加入少于10%的铜和少量磷.就可以使钢材生锈的速度减半,他们把这 相似文献
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计算数列极限有着多种多样的方法,除了要熟练运用极限的四则运算法则,极限和无穷小量之间的关系和初等函数的连续性以外,还要掌握和运用较多的方法和技巧.其主要方法有:1.四则运算法.2.利用重要极限求数列极限.3.单调有界数列法.4.利用定积分求数列极限. 相似文献
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大米中镉含量的测量不确定度评定 总被引:1,自引:0,他引:1
分析了石墨炉原子吸收光谱法测定大米中镉含量不确定度的各分量,对其测量不确定度进行合理的评定,结果表明:大米样品中镉的含量为0.18 mg/kg时,其扩展不确定度为0.01 mg/kg(k=2),不确定度主要是最小二乘法拟合标准工作曲线求得样品浓度过程和测试过程随机效应引入的。 相似文献
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本文综述了氧化锆及其复相陶瓷超塑性的研究现状,论述了陶瓷超塑性的变形机理,微观特征和断裂特性。同时,分析和对比了陶瓷超塑性与金属超塑性的特点。目前,对于正确理解超塑性陶瓷的变形机理,还需进行大量工作。 相似文献
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超支化聚合物因其独特的结构和性能特点,已在众多领域得到应用,特别是在树脂改性中的研究发展迅速。综述了超支化聚合物作为树脂改性剂在聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、聚碳酸酯、尼龙6等热塑性树脂和环氧树脂、不饱和聚酯树脂、乙烯基酯树脂等热固性树脂中的应用研究进展,超支化聚合物可作为热塑性树脂的加工助剂、流变学改性剂、增容剂或增强剂以及热固性树脂的增韧剂。同时对超支化聚合物在树脂改性中的应用研究方向做出了展望。 相似文献
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依据国标GB/T 22388-2008规定,采用高效液相色谱法对液态奶中三聚氰胺的含量进行了检测。建立数学模型,分析确定检测液态奶中三聚氰胺含量的不确定度来源,并对测量过程中的不确定度分量进行逐层分析与合成,得到合成标准不确定度和扩展不确定度分别为0.054 mg/kg和0.11 mg/kg。计算结果显示由样品溶液测量重复性、标准溶液测量重复性、标准溶液配制过程引入的不确定度分量对合成标准不确定度贡献较大,是不确定度的主要来源;由样品称量、定容引入的不确定度相对来说较小。 相似文献
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Over the last 15 years there has been an increasing incidence of failure in rockbolts used in underground mines in Australia.
Failures have also been observed in the United Kingdom where Australian Technology rockbolting is also used. Most of the failures
in the United Kingdom were found to be initiated by corrosion pits, but in Australia, the fractures were considered likely
to be due to stress corrosion cracking (SCC). This paper reports a metallurgical study of 44 failed rockbolts from four different
underground mines in Australia. The study confirmed that failure was generally due to SCC and showed that this was usually
initiated by bending of the bolts that occurred due to lateral movement of the rock strata. It also showed that many of the
failed bolts had very low toughness with Charpy impact values of 4–7 Joules. 相似文献
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We often assume the standard linear model with uncorrelated observations for comparison of designs without realizing a possible
presence of correlation in observations. In this paper we present several change of variance functions including the one given
in Zhou (2001) for comparing designs in presence of possible correlation in observations. We find a design by minimizing one
of our proposed change of variance functions in a simple response surface setup. We then compare its performance with all
variance design, all bias design, and the design making the average variance equal to the average squared bias. We also compare
a second order rotatable design with a non-rotatable design. The rotatable design is better than the non-rotatable design
with respect to A-, D-, and E- optimality criterion functions under the standard linear model with uncorrelated observations.
We observe that the rotatable design may not perform better than the non-rotatable design with respect to the change of variance
functions. We present some important properties of the change of variance functions. We find that the A-optimum designs may
perform poorly with respect to a change of variance function. 相似文献
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The study presented in this paper is placed in the context of the frequency analysis of acoustic emission in concrete. The purpose is to study the ability to identify an acoustic emission event by deducing its spectrum from a detected signal. The identification is carried out progressively so as to separate the various functions involved in the acoustic emission process, and to approach the usual conditions of acoustic emission processing during fracture tests of concrete specimens. Impulses of different forms are generated on the surface of concrete test specimens, and the signals detected are analyzed. The identification of signals takes into account the frequency response of the transducers and the wave attenuation as function of the frequency. 相似文献