发射光谱分析法测量不确定度的评定与应用

JJF1059-1999<测量不确定度的评定与表示>指出可以用不确定度作为评判分析方法准确度的标准,使得借助标准样品来进行分析的诸多分析方法有望成为标准分析方法.本文对X射线荧光光谱分析和光电直读光谱分析的测量不确定度在铜及铜合金中的评定与应用进行了讨论.     

ICP-MS测量溶液中痕量Sm的不确定度评定

为了更合理、科学地表示测量结果 ,本文按照 GUM和国家质量技术监督局颁布的计量技术规范 ,对电感耦合等离子体 -质谱 (ICP- MS)测量溶液中痕量 Sm的不确定度进行了评定 ,提供了计算过程所需各参数的采集和计算方法 ,评定了各标准不确定度分量、合成标准不确定度、自由度和扩展不确定度。此方法还可为类似仪器测量结果不确定度的评定提供参考。     

石墨炉原子吸收光谱法测定地球化学样品中微量铬结果不确定度评定

根据《测量不确定度评定与表示》指南,对石墨炉原子吸收光谱法测定地球化学样品中微量铬的结果进行了不确定度评定.分析了不确定度的主要来源,包括样品称量过程、待测溶液定容体积、标准溶液配制、校准曲线拟合以及待测溶液重复测量产生的不确定度.对各个不确定度分量进行量化分析计算,评估了铬含量的合成标准不确定度和扩展不确定度.     

原子荧光光谱法测定化妆品中汞的结果不确定度评定

本文介绍了原子荧光光谱法测定化妆品中汞的不确定度评定方法 ,分析和识别在分析过程中的不确定度来源 ,较为全面地评定了测量不确定度。根据最小二乘法原理计算校准曲线的标准不确定度 ,采用极差法评定测量次数较少时引起的标准不确定度。对原子吸收法、电感耦合等离子体 -原子发射光谱法和原子荧光光谱法等测定结果的不确定度的评定具有参考作用。     

氨茶碱注射液中无水茶碱含量的不确定度评定

分析了氨茶碱注射液中无水茶碱含量测定过程中含量的重复性测量、样品的取样量、样品的稀释体积和紫外分光光度法的测量等因素对含量测定不确定度的影响.量化了各分量的相对标准不确定度,进而得出合成标准不确定度和扩展不确定度.建立的不确定度评定方法适用于分光光度法测定氨茶碱注射液中无水茶碱含量的不确定度分析.     

石墨炉原子吸收光谱法测定化探样品中痕量银的不确定度评定

运用测量不确定度评定与表示的理论,分析了用石墨炉原子吸收光谱法测定化探样品中银的不确定度.指出了不确定度分量由称样质量、标准溶液配制、校准曲线拟合、测量重复性、试液定容体积组成.对各个分量进行量化,合成得到测量结果的标准不确定度,通过乘以95％概率下的扩展因子2,获得测量结果的扩展不确定度.     

气相色谱法测定海水中狄氏剂的不确定度评定

采用末取代聚苯乙烯/二乙烯基苯（Cleanert PS）固相萃取-气相色谱法测定海水中狄氏剂浓度,对测量结果的不确定度进行了评定.分析了测量程序中不确定度的各项来源,包括样品采集、标准溶液制备、校准曲线、前处理方法回收率等分量引入的不确定度及其计算方法,最后合成标准不确定度,通过乘以95％概率下的扩展因子2,获得测量结果的扩展不确定度.     

测量不确定度的评定与表示

测量不确定度和如何正确评定与表示，是个极其重要的问题，文章指出了研究不确定度的意义，介绍了不确定度的有关概念，按实际工作的测量模型，给出了标准不确定度Ａ类、Ｂ类评定的各种具体方法，提出了标准不确定度的俣成方法与展伸不确定度的给出方法，对不确定度评定与表示的程序进行了汇总，并举出了应用实例。     

ICP-AES测定沘江流域农田土壤中重金属元素Pb的不确定度评定

土壤是人类及各种生物赖以生存的环境基础,土壤中重金属元素的含量高低与人类的生活及各种生物的生存息息相关,其含量达到一定程度时则会危及人类及各种生物的健康,因此,准确测定土壤中的重金属元素含量就显得极为重要,具有极强的现实意义,而测量不确定度可判定测量结果的准确程度.本文以测定研究项目中所采集的沘江流域农田土壤中重金属元素Pb为代表,通过ICP-AES测定土壤样品中重金属元素Pb的不确定度的评定实践,分析了该方法测定过程中的不确定度来源,建立了数学模型,并计算了各标准不确定度分量、合成标准不确定度、扩展不确定度等,为准确评定研究项目土壤中的重金属污染程度提供了科学依据.     

基于可调谐激光的CO监测仪的不确定度评定

采用可调谐二极管激光吸收光谱技术(TDLAS)对CO气体的浓度进行测量,应用整体二次谐波最小二乘法对测量信号的实验数据进行反演处理。基于可调谐二极管激光吸收光谱技术, 对CO在线监测仪测量结果的不确定度来源进行了分析, 采用直接评定法对各种因素引起的不确定度分量、标准不确定度和合成不确定度进行了评定。实验结果表明, 仪器示值引入的不确定度、标准气体浓度定值的不确定度以及环境温度变化和电源电压波动引入的不确定度是影响测量不确定度的主要因素。     

ICP-AES法测定钛合金中的6种元素

用ＨＣｌ分解钛合金样品,直接用ＩＣＰ－ＡＥＳ法测定其中的Ｃｒ、Ｍｏ、Ｆｅ、Ｓｉ、Ａｌ及Ｚｒ６种元素,方法简便、快速、测定各元素含量范围为０．２８％－６．５１％,相对标准偏差为０．７２％－５．０７％,回收率为９７．４％－１０２％。     

Effect of alloying on magnetic properties of Fe-Cr-12 wt% Co permanent magnet alloys

Effect of alloying additional elements (Al, Si, Ti, V, Ni, Cu, Zr, Nb and Mo) with Fe-22/30 wt% Cr-12 wt% Co permanent magnet alloys manufactured by magnetic aging has been systematically studied with magnetic measurements and transmission electron microscopy (TEM), on a laboratory scale. It is found that the alloying shifts the optimum Cr content to a lower lever. Ti and Si show the greatest enhancement on magnetic properties yet narrow the optimum magnetic aging temperature range. Mo, Nb and Cu, when used together with Si, promote magnetic properties and widen the optimum magnetic aging temperature range. Ni and Zr are simply magnetic diluents. V is good for the magnetic properties only at a large amount of addition. The origin of alloying effects explored by TEM microscopy is attributed to the degree of particle entanglement as well as elongation.     

Atomistic modeling of ternary additions to NiTi and quaternary additions to Ni–Ti–Pd,Ni–Ti–Pt and Ni–Ti–Hf shape memory alloys

The behavior of ternary and quaternary additions to NiTi shape memory alloys is investigated using a quantum approximate method for the energetics. Ternary additions X to NiTi and quaternary additions to Ni–Ti–Pd, Ni–Ti–Pt, and Ni–Ti–Hf alloys, for X=Au, Pt, Ir, Os, Re, W, Ta,Ag, Pd, Rh, Ru, Tc, Mo, Nb, Zr, Zn, Cu, Co, Fe, Mn, V, Sc, Si, Al and Mg are considered. Bulk properties such as lattice parameter, energy of formation, and bulk modulus of the B2 alloys are studied for variations due to the presence of one or two simultaneous additives.     

A first principles calculation of site occupancy of the B2 phase in Ti2AlX (X=V,Cr, Fe,Mo, Ta,Nb, Zr,Hf and Re) intermetallics

The site occupancy of the B2 phase in Ti₂AlX (X=V, Cr, Fe, Mo, Ta, Nb, Zr, Hf and Re) intermetallics have been studied using first principles pseudo potential plane wave method.The Ti, Al and X atoms are arranged in five different ways, in the lattice sites corresponding to B2 structure of Ti₃Al. In Ti₃AlX, the X atoms are substituted at the Ti and / or Al sites. Further, the equilibrium lattice constants and the formation energy (E_for) of these intermetallics with different site occupancies in the B2 phase have been predicted. The formation energy values suggest that the B2 phase is stable in all alloys. Amongst the five cases in a particular alloy, stable configuration is identified with the minimum E_for and is further considered for the calculations of mechanical properties. All the alloys are mechanically stable in terms of Born stability criteria and show anisotropic behaviour. All the alloys display ductile behaviour in terms of G/B ratio.     

Nonlinear continual growth model of nonuniformly scaled reliefs as applied to the rigorous analysis of the X-ray scattering intensity of multilayer mirrors and gratings

It is revealed that certain terms entering into the nonlinear continual equation describing thin-film growth enable its application to the simulation of the surfaces of multilayer mirrors and gratings with a large height and/or jumps of boundary-profile gradients. The proposed model characterizes both variations in the power spectral-density function of the surface of Al/Zr multilayer mirrors and the smoothing and shift of the boundaries of Mo/Si and Al/Zr gratings grown on Si substrates with triangular groove profiles by means of magnetron and ion-beam deposition. Rigorous calculations indicate that the intensities of diffuse X-ray scattering by Au mirrors, which have similar boundary profiles with Gaussian and exponential autocorrelation functions, differ substantially from each other. Computer simulation of the growth of Mo/Si and Al/Zr multilayer gratings is performed. On the basis of the calculated boundary profiles, the absolute diffraction efficiencies of the Mo/Si and Al/Zr gratings are found via the integral equation method in the extreme UV region. It is demonstrated that the proposed comprehensive approach to calculations of the boundary profiles and the intensities of short-wavelength scattering from multilayer mirrors and gratings makes it possible to carry out studies comparable in accuracy to measurements based on synchrotron radiation.     

采用不确定度评定和分析实验误差初探

以国际《测量不确定度表达指南》和国家计量技术规范《JJF1059-1999测量不确定度评定与表示》为依据,结合实验实践,阐述了不确定度的定义内涵、分析意义以及不确定度与误差的区别和联系,给出了用不确定度评定测量结果的一些方法。     

L12型铝合金的结构、弹性和电子性质的第一性原理研究

运用第一性原理方法研究了L12型铝合金相Al3Sc和Al3Zr的晶体结构、电子结构和弹性.结合能和形成能的计算表明,两种合金具有较强的合金化能力,且Al3Zr较Al3Sc具有更强的结构稳定性.电子结构分析表明,费米能级以下较多的价电子数决定了Al3Zr具有较强的结构稳定性.计算并分析比较了两种合金相的单晶弹性常数(C11,C12和C44)以及多晶弹性模量(体弹性模量B、剪切模量G、杨氏模量Y、泊松比ν和各向异性因子A).通过对比实验和其他理论计算结果,进一步分析和解释了两种合金相的力学性质.     

杂质浓度对Zr替位掺杂γ-TiAl合金的结构延性和电子性质的影响

以Zr替代Ti(或Al)掺杂γ-TiAl体系为研究对象, 掺杂浓度(摩尔比)分别为1/54, 1/36, 1/24和1/16. 采用基于密度泛函理论的第一性原理方法, 计算研究了Zr掺杂γ-TiAl体系的晶体结构及其稳定性、延性和电子性质等. 结果显示, Zr替位掺杂, 可以改变γ-TiAl基合金的结构对称性. 计算的形成能表明, Zr替代Ti原子会使体系的形成能降低, 而Zr替代Al原子会使体系的形成能增加. 因而, 在掺入γ-TiAl时, Zr更倾向于替代Ti 原子, 但是Zr替代Al原子也具有一定的可能性, 从而会产生多样的掺杂体系, 对于改善合金的性质具有重要意义. 对各个体系轴比的计算与分析表明, 当掺杂浓度为1.85 at%–6.25 at% 时, Zr替代Al原子会使体系的轴比减小、接近于1, 从而改善合金的延性效果明显. 能带结构显示各个Zr掺杂γ-TiAl体系均具有金属导电性. 对电子态密度和布居数的分析表明, Zr替代Al原子后, Zr与其邻近Ti原子的共价键结合强度大为降低, 导致合金体系中的Ti-Al(Zr)键的平均强度明显减弱, 金属键增强, 这是改善γ-TiAl合金延性的重要因素.     

Surface energies of the solid solutions between Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W

The surface energy for different surface orientations of the solid solutions as a function of concentration formed by Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W is computed and analyzed using the BFS method for alloys. Similarities and differences among the different binary alloys are examined in terms of strain and chemical effects.     

Structural dependence of the superconducting transition temperature in liquid-quenched alloys based on the group IV B elements

The structural modifications and superconducting transition temperatures in TiPd, ZrPd, ZrMo, and HfPd thin-foil alloys (containing up to ～95 at.% of the group IV B elements) obtained from the liquid state have been investigated. Contrary to some previously reported results, a ‘single phase’ of the body-centered cubic β structure cannot be retained in alloys containing more than 90 at.% of the IV B elements at room temperature. The present findings provide a more reliable assessment of the transition temperatures for the cubic β phase.