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文中对火焰原子吸收法测定土壤中Pb、Cu含量的不确定度来源进行了详细分析,包括:标准溶液引入的不确定度、样品称量引入的不确定度、容量瓶和移液管体积引入的不确定度、温度引入的不确定度、校准曲线引入的不确定度和测量的重复性引入的不确定度,并按数学模型计算出各不确定度分量、合成标准不确定度和扩展不确定度。结果表明:标准物质的稀释过程、曲线的校准和样品重复性试验为不确定度的主要来源。 相似文献
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对电感耦合等离子体原子发射光谱(ICP-OES)法测金属硅中硼的不确定度来源进行了详细分析,对测定过程中的主要不确定度进行了合理的评定,包括:样品称量引入的不确定度、校准曲线引入的不确定度、容量瓶和移液管体积引入的不确定度以及测量的重复性和仪器引入的不确定度,最后合成标准不确定度乘以95%置信概率下的扩展因子2,获得测量结果的扩展不确定度,并确定了分析结果的置信区间。 相似文献
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以国际硬度计为例介绍了橡胶物理实验室在给出试验结果、进行设备校准和期间核查时,测量不确定度评定的方法。 相似文献
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对MPX-2000型磨损试验机进行改造并设计了专用夹具,利用金属圆环与衬套橡胶盘状试样在油水介质和油水砂介质中进行螺杆-衬套副的磨损模拟试验,测定衬套橡胶在不同法向载荷和滑动速度条件下的摩擦因数和磨损量。结果表明,衬套橡胶试样在油水和油水砂介质中的摩擦因数随法向载荷的增大而减小,随滑动速度的提高先增大后有所减小,而磨损量随法向载荷的增大而增加,随滑动速度的提高而减小。衬套橡胶试样在油水介质中的磨损主要表现为摩擦机理,而在油水砂介质中则主要表现为摩擦机理和湿磨粒磨损机理。 相似文献
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In this article, the effects of the operating conditions, i.e., load, oscillation speed, temperature, and contact modes on the friction behavior of polyethylene were studied through the SRV vibration friction test machine, the MHK-500 friction and wear test machine, as well as an on-line temperature testing device. The experimental results showed that the friction coefficient μ of polyethylene increases with increase of the oscillation frequency and amplitude, the speed, and PV value, while load has a quite complex impact on μ; suitable choice of load could reduce μ and smoothen the friction process. Contact modes of friction pairs have considerable effects on μ, because all the real contact area of the friction assembly, the pressure, the indentation of surface asperities, as well as the temperature rise and distribution in the contact region are related to contact modes. Temperature is a key factor determining the viscoelastic properties of polyethylene, and therefore has great effect on μ. On-line temperature testing offers a way to reveal the relations between temperature and the friction behavior of polyethylene. All the results obtained provide the basic data for establishing mathematical models and computational simulation methods to describe and study the tribological behavior of some polymer materials. © 1995 John Wiley & Sons, Inc. 相似文献
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通过测试ABS、PA—GF30在不同条件下的泊松比,从纵向引伸计间距、拉伸速率以及取值范围分析比较了ISO527—1、ASTMD638以及GB/T1040.1中关于塑料泊松比测试方法的异同。结果表明,对于常规ISO1A型拉伸样条,可优先采用在5mm/min的速率下测试,当应变取值范围在0.3%~0.8%之间,会得到较理想的测试结果。 相似文献
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The instantaneous elastic recoveries of poly(trimethylene terephthalate) (PTT), PET, and PBT filaments were comparatively analyzed by a tensile testing machine. The conditions of the measurement were studied and the mechanism of instantaneous elastic recovery of these three aromatic polyester filaments is discussed. The instantaneous elastic recovery of PTT filaments was significantly higher than those of PBT and PET filaments. Moreover, PTT filaments had a high instantaneous elastic recovery even at a high elongation of 20%. The outstanding instantaneous elastic recovery of PTT filaments resulted from its helical conformation in crystal lattice, which responded immediately to the applied stress and deformed as though it was a coiled spring; we suggest it was a quasispring elastic recovery mechanism. When we measured the instantaneous elastic recovery of, PTT filaments with the tensile testing machine, it was appropriate to set up the crosshead speed at 500 mm/min with an elongation of 20% and a load of 0.5 cN/tex. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1967–1975, 2004 相似文献
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透平膨胀机在空气分离设备中,是用来使气体膨胀输出外功以产生冷量的机械,由于其具有很多优点,因而在空气分离行业中应用广泛。但在使用中也经常发生超速、机后压力超高、卡机等各种故障,现就几种常见故障进行分析,并提出解决方法,以保证设备的正常运行。 相似文献
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为了深入研究浇注式沥青混凝土沥青混合料在温度、应力耦合作用下的三轴蠕变特性,采用MTS815试验机开展了不同温度、不同应力水平和不同围压条件下的三轴蠕变试验,获取了相应的蠕变曲线,并将改进的Burgers模型推广到三维形式,用来描述浇注式沥青混凝土的蠕变本构关系。研究结果表明:浇注式沥青混凝土蠕变曲线的第一阶段不明显,这反映出其内部空隙率较低;蠕变变形值随温度升高和偏应力水平增大而明显增大,这反映出高温重载共同作用是浇注式沥青混凝土路面出现车辙的决定性因素;蠕变变形随围压增大略有减小,围压对蠕变变形有抑制作用,三轴蠕变试验获得的蠕变规律较之单轴蠕变试验更能反映实际受力过程中的变形规律,三维的改进Burgers模型能够准确反映热力耦合作用下浇注式沥青混凝土的蠕变特性。 相似文献
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介绍了我国水性涂料检测的标准,实验室依据标准对涂料检测时应注意选用的问题。判定涂料品质的重要手段,就是检测中如何正确采用和执行技术标准直接影响测定结果。检测方法标准几乎涵盖了涂料、涂膜及其使用性能,涂料检测中正确采用和执行这些技术标准不仅可以确保测试结果的唯一性,研发生产、使用提供正确有效的数据。 相似文献