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101.
I. Kuselman 《Accreditation and quality assurance》1998,3(3):131-133
It is argued that results of uncertainty calculations in chemical analysis should be taken into consideration with some caution
owing to their limited generality. The issue of the uncertainty in uncertainty estimation is discussed in two aspects. The
first is due to the differences between procedure-oriented and result-oriented uncertainty assessments, and the second is
due to the differences between the theoretical calculation of uncertainty and its quantication using the validation (experimental)
data. It is shown that the uncertainty calculation for instrumental analytical methods using a regression calibration curve
is result-oriented and meaningful only until the next calibration. A scheme for evaluation of the uncertainty in uncertainty
calculation by statistical analysis of experimental data is given and illustrated with examples from the author's practice.
Some recommendations for the design of corresponding experiments are formulated. 相似文献
102.
Guo-xiang Xu Lu Qi Bi-tao Yu Lei Wen Department of Applied Chemistry College of Chemistry Molecular Engineering Peking University Beijing China Department of Inorganic Nonmetal Materials School of Materials Science Engineering University of Science Technology Beijing Beijing China 《高分子科学》2006,(3):307-313
PVC disulfide (2SPVC) was synthesized by solution crosslink and its molecular structure was confirmed by infrared spectrum. 2SPVC's specific area is 36.1 m2·g-1 tested by stand BET method, and granularity experiment gives out the particle size of d0.5= 11.3μm. With SEM (Scanning Electron Microscope) experiment the surface morphology and particle shape of 2SPVC were observed. Cyclic voltammetry (scan rate: 0.5 mV·s-1) shows that 2SPVC experience an obvious S-S redox reaction in charge-discharge process. When 2SPVC was used as cathode material for secondary lithium battery in a 1 mol·L-1 solution of lithium bis(trifluoromethylsulfonyl) imide (Li(CF3SO2)2N) in a 5:45:50 volume ratio mixture of o-xylene (oxy), diglyme (DG) and dimethoxymethane (DME) at 30℃, the first discharge capacity of 2SPVC is about 400.3 mAh·g-1 which is very close to its theoretical value (410.5 mAh·g-1) at a constant discharge current of 15 mA·g-1. It can retain at about 346.1 mAh·g-1 of discharge capacity after 30 charge-discharge cycles. So 2SPVC is a very promising cathode candidate for rechargeable lithium batteries. 相似文献
103.
热敏电阻温度计的设计与制作 总被引:1,自引:0,他引:1
本文介绍了设计性实验“热敏电阻的设计与制作”的实施情况。说明了只要选题合适、要求恰当,设计性实验不仅可行,而且对物理实验训练的总结提高十分有效。 相似文献
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采用纳秒脉冲激光对石化设备普遍使用的20钢表面锈蚀层以及油污进行了激光清洗试验,通过正交实验法得到优化后的激光清洗工艺参数,在激光功率18 W,激光脉冲重复频率75kHz,扫描速度3 000mm/s的清洗工艺参数下可有效去除20钢表面的锈蚀层;在激光功率20 W,激光脉冲重复频率75 kHz,扫描速度2 250 mm/s的清洗工艺参数下可有效去除20钢表面附着的油污。分析了激光清洗前后材料表面形貌的变化,研究了激光清洗前后表面的显微硬度以及耐腐蚀性,结果表明:激光清洗可以在不改变材料的耐腐蚀性能的同时提升材料表面的显微硬度,从而达到理想的激光清洗效果。 相似文献
108.
Liang Wang Luying Li Shuangfeng Jia Weiwei Meng Yongfa Cheng Zunyu Liu Li Li Shuwen Yan Yihua Gao Jianbo Wang Jiang Tang 《Advanced functional materials》2023,33(6):2210286
Ruddlesden–Popper (RP) faults are well known in oxide perovskites, and are also observed in promising metal halide perovskites. However, the effect of RP faults on optical properties of perovskite has not been systematically investigated. In this study, it is found that RP faults are common planar faults in all-vacuum deposited CsPbBr3-based perovskite polycrystal thin films, and the density of RP planar faults can be greatly increased by non-stoichiometric composition (Cs-rich) as well as reduced dimensionality (quasi-2D) strategies. The photoluminescence (PL) measurement reveals monotonically increasing peak intensities with higher densities of RP planar faults from Cs-rich, quasi-2D to Cs-rich & quasi-2D samples. The corresponding atomic-scale differential phase contrast maps indicate strongly confined charges within the RP planar fault network, which explains well the relationship between PL enhancement and the density of RP planar faults, and offers an alternative pathway for tailoring the optoelectronic properties of perovskite. 相似文献
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