液相色谱法测定水中甲萘威不确定度评价

介绍了液相色谱法测定水中甲萘威不确定度的方法及原理,主要对液相色谱法测定水中甲萘威引起的不确定度进行了分析以及量化,认为不确定度主要来源于标准溶液和绘制标准曲线的过程以及样品的前处理过程和样品的重复测定过程,其中绘制标准曲线引入的不确定度和样品的前处理过程引入的不确定度所占比例较大。     

PVC树脂悬臂梁冲击强度测试的不确定度评定

本文以PVC树脂为测试材料,采用GB/T 1843-2008规定的方法,测试其悬臂梁冲击强度,并对测试过程中的不确定度分量进行分析和评定。PVC树脂样品测定结果为E=(13.22±0.94)k J/m2,k=2,P=95%。测量重复性是测量结果不确定度的主要来源。     

直接汞分析仪测定化妆品中汞含量不确定度评定

目的用直接汞分析仪测定化妆品中汞的含量,对测量结果进行不确定度评定。方法根据测量不确定度评定理论,通过实际样品测定,分析直接汞分析仪在测定过程中不确定度的可能来源,计算测定化妆品中汞含量的不确定度。结果分析测量不确定度的来源,对合成不确定度进行计算,扩展不确定度为±0.078μg/g。结论直接汞分析仪测定化妆品中汞的不确定度主要来源于待测溶液测定中标准工作曲线的拟合,相比于传统方法省去了样品定容、样品前处理等因素带来的不确定度影响。     

高效液相色谱测定食品中的苯甲酸、山梨酸、糖精钠测量不确定度分析

按照国家标准GB/T23495-2009《食品中苯甲酸、山梨酸和糖精钠的测定高效液相色谱法》[1]中规定食品中苯甲酸、山梨酸和糖精钠测定采用高效液相色谱法,对测定苯甲酸、山梨酸、糖精钠含量的不确定度来源进行分析讨论,以求其结果的不确定值。方法:根据高效液相色谱测定食品中的苯甲酸、山梨酸、糖精钠含量的测定原理,全面考虑了整个分析过程的不确定度来源,建立其结果的数学模型,并计算其测定过程的不确定度分量,结果的不确定度及扩展的不确定度。结论:提出的方法可适用于高效液相色谱法测定食品中的苯甲酸、山梨酸、糖精钠测量不确定度的评定。     

热解析—气相色谱法测定空气中苯系物的不确定度评定

《民用建筑工程室内环境污染控制标准》(GB50325-2020)中苯、甲苯、二甲苯浓度测定,由热解析-气相色谱法测定,分析苯系物浓度中不确定度的主要来源由量器、标准溶液、样品采集过程、标准曲线绘制、样品的重复测定引入。分析得出:影响不确定度分量最大的是标准曲线线性拟合过程,需考虑到吸附管本身的吸附和解析的效率、仪器条件。在未考虑吸附与解析条件下,测定的合成相对标准不确定度为0.0273～0.4322。     

离子色谱法测定水泥中的氯离子含量

本文对比了硝酸加热分解-离子色谱法与纯水超声提取-离子色谱法测定水泥中的氯离子含量,通过对其的标准曲线、样品前处理、回收率、重复性、检出限的分析,验证了硝酸分解-离子色谱法测定水泥中的氯离子的可行性。     

锌试剂法测定循环水中锌离子含量的不确定度评定

采用锌试剂分光光度法测定循环水中锌离子浓度,分析了影响测定结果的各主要不确定度的来源,并对1个样品测定结果的合成标准不确定度和扩展不确定度进行了评定。结果表明,该方法测量不确定度的主要来源为标准曲线拟合求样品浓度和重复性测定引入的不确定度。     

废水氨氮测量不确定度的评定

采用纳氏试剂法测定废水中氨氮含量，其不确定度来源于标准曲线、取样体积和样品的重复测定，通过对测定过程涉及到的标准储备液、标准曲线绘制、标准曲线拟合、取样体积、移液管等因素进行分析，确定其产生的不确定度，进而提高测量的准确度。实验结果表明，通过对废水中氨氮不确定度的评定，能够准确反映实验过程中产生的不确定度的所有来源。     

测定生活饮用水用聚氯化铝中铬含量的不确定度评定

本文根据JJF 1059.1-2012测量不确定度评定准则,对测定聚氯化铝中铬含量进行不确定度评定。以某一聚氯化铝溶液为例,对测量过程进行分析,识别并计算出不确定度各分量,最终计算出该聚氯化铝溶液中铬含量为（0.000403±0.0000193）%。评定结果表明,实验的主要不确定度由样品重复性测定和样品回收率引入。     

离子色谱法测定水中氟化物的不确定度评定

根据《测量不确定度评定与表示》(JJF1059. 1—2012),探讨了离子色谱法测定水中氟化物的不确定度,并对测量不确定度进行了评估。结果表明,水中氟化物浓度为1. 30 mg/L,扩展不确定度为0. 08 mg/L(包含因子k=2),不确定度的最大来源是离子色谱仪测量。     

聚氯乙烯封边条中树脂含量的测定

聚氯乙烯封边条中树脂含量是决定其力学强度、柔韧性、使用寿命的关键因素。本文采取溶解-沉淀法从聚氯乙烯封边条中提取出树脂,结合红外光谱法鉴别,测定其中树脂含量,无需大型仪器设备,操作简便快捷,结果准确可靠。     

凝胶渗透色谱(GPC)表征聚丙烯相对分子量及其分布的方法研究

本文研究了一种凝胶渗透色谱表征聚丙烯树脂相对分子质量及其分布的方法,并将本方法的重复性、准确度与ASTM标准进行了对比,与文献方法进行对比.结果表明,本方法表征聚丙烯树脂相对分子质量及分布重复性好,准确度高.     

Parameter uncertainty analysis of the non-point source pollution in the Daning River watershed of the Three Gorges Reservoir Region, China

The generation and formation of non-point source pollution involves great uncertainty, and this uncertainty makes monitoring and controlling pollution very difficult. Understanding the main parameters that affect non-point source pollution uncertainty is necessary to provide the basis for the planning and design of control measures. In this study, three methods were adopted to do the parameter uncertainty analysis with the Soil and Water Assessment Tool (SWAT). Based on the results of parameter sensitivity analysis by the Morris screening method, the ten parameters that most affect runoff, sediment, organic N, nitrate, and total phosphorous (TP) were chosen for further uncertainty analysis. First-order error analysis (FOEA) and the Monte Carlo method (MC) were used to analyze the effect of parameter uncertainty on model outputs. FOEA results showed that only a few parameters had significantly affected the uncertainty of the final simulation results, and many parameters had little or no effect. The SCS curve number was the parameter with significant uncertainty impact on runoff, sediment, organic N, nitrate and TP, and it showed that the runoff process was mainly responsible for the uncertainty of non-point source pollution load. The uncertainty of sediment was the biggest among the five model output results described above. MC results indicated that neglecting the parameter uncertainty of the model would underestimate the non-point source pollution load, and that the relationship between model input and output was non-linear. The uncertainty of non-point source pollution exhibited a temporal pattern: It was greater in summer than in winter. The uncertainty of runoff was smaller compared to that of sediment, organic N, nitrate, and TP, and the source of uncertainty was mainly affected by parameters associated with runoff.     

大直径桩荷载与沉降关系的改进离散灰色模型

大直径桩荷载与沉降关系曲线一般为缓变形,未必符合指数曲线特性,很可能服从其他非线性特性,为此对离散灰色DGM(1,1)模型进行拓展,建立了非线性离散灰色模型。以此模型为基础利用优化理论求出初始迭代点,提高了非线性离散灰色模型的精度。利用该模型预测大直径桩荷载与沉降曲线,预测值与试验值吻合较好,与GM(1,1)模型、离散灰色DGM(1,1)模型相比,预测精度进一步提高,为大直径桩的荷载与沉降关系曲线预测提供了新的方法。     

潜在滑移线原理求解浅基的极限承载力

采用非线性有限元方法,对长条形浅基础进行二维分析,得到应力应变场,再按潜在滑移线理论绘出相应的潜在滑移线,依据潜在滑移线理论,确定地基的承载力系数,可为相关工作和理论研究提供借鉴。     

Instantaneous pavement condition evaluation using non-destructive neuro-evolutionary approach

In this paper, a hybrid neural network (NN)-genetic algorithm (GA) based non-destructive pavement auscultation method for instantaneous airfield infrastructure condition assessment is discussed. NNs are employed for finite element aided forward prediction of pavement surface deflections resulting from non-destructive test impulse loading and the GAs are used for global optimisation of the pavement structural parameters by matching the NN predicted deflections with the measured pavement response. This hybrid approach takes advantage of the non-linear estimation capability provided by neural networks trained using finite element (FE) solutions in modelling the stress-dependent behaviour of unbound pavement geo-materials while improving the robustness to measurement uncertainty through the application of genetic algorithms. The performance of the developed hybrid pavement auscultation technique is evaluated through extensive field studies conducted at a state-of-the-art full-scale airfield pavement test facility. The results show that this approach is promising for real-time condition evaluation of airfield pavement infrastructure systems.     

EVA防水板中乙酸乙烯酯含量测定方法探讨

提出通过二次蒸馏水解返滴定法和衰减全反射(ATR)红外光谱法测试EVA防水板中乙酸乙烯酯含量.结果显示,二次蒸馏水解返滴定法测试不同VA含量的相对标准偏差在2.61％～4.46％之间;ATR红外光谱法中利用1740cm-1(C=O键)吸收峰的吸光度与719cm-1(C-H键)吸收峰的吸光度之比,与二次蒸馏水解返滴定法测...     

Risk minimisation of FGD gypsum leachates by incorporation of aluminium sulphate

The incorporation of aluminium sulphate to (flue gas desulphurisation) FGD gypsum before its disposal was investigated as a way to minimise the risk supposed by the high fluoride content of its leachates. Using a bath method the kinetic and equilibrium processes of fluoride removal by aluminium sulphate were studied at fluoride/aluminium molar concentration (F/Al) ratios in the range 1.75 10(-2)-1.75 under the pH conditions (about 6.5) of FGD gypsum leachates. It was found that fluoride removal was a very fast process at any of the (F/Al) ratios subject of study, with equilibrium attained within the first 15 min of interaction. High decreases in solution fluoride concentrations (50-80%) were found at the equilibrium state. The use of aluminium sulphate in the stabilization of FGD gypsum proved to greatly decrease its fluoride leachable content (in the range 20-90% for aluminium sulphate doses of 0.1-5%, as determined by the European standard EN 12457-4). Such fluoride leaching minimisation assures the characterization of this by-product as a waste acceptable at landfills for non-hazardous wastes according to the Council Decision 2003/33/EC on waste disposal. Furthermore, as derived from column leaching studies, the proposed stabilization system showed to be highly effective in simulated conditions of disposal, displaying fluoride leaching reduction values about 55 and 80% for aluminium sulphate added amounts of 1 and 2%, respectively.     

EDTA容量法结合ICP-AES法测定氟化镁中的镁

建立了一种EDTA容量法结合ICP-AES法测定氟化镁中镁含量的方法,该方法适用于不同生产工艺制备的氟化镁样品,弥补了GB/T 21994.4-2008《氟化镁化学分析方法第4部分:镁含量的测定EDTA容量法》在测定某些特殊工艺制备的氟化镁样品中镁含量明显偏低的不足.该方法的相对标准偏差小于0.5％,回收率在99％～1...     

Uncertainty analysis of parameters in non‐point source pollution simulation: case study of the application of the Soil and Water Assessment Tool model to Yitong River watershed in northeast China

Uncertainty analysis of the model parameters in non‐point source pollution (NPSP) simulation is important because of its great effects on predictions and decision‐making. Understanding the main parameters that effect the uncertainty of NPSP is necessary to provide the basis for formulating control measures. In this study, two methods were applied to conduct parameter uncertainty analysis for Soil and Water Assessment Tool (SWAT). Sobol’ method was used to screen out the model parameters with great effects on the runoff, sediment, total nitrogen (TN) and total phosphorus (TP). The results obtained by sensitivity analysis were used subsequent model calibration and further uncertainty analysis. Monte Carlo (MC) method was employed to analyse the effects of parameter uncertainty on the model outputs. However, such problems are time‐consuming because the MC method required to invoke simulation model thousands of times. To address this challenge, a kriging surrogate model was developed to improve the overall calculation efficiency. The results obtained by sensitivity analysis showed that curve number value (CN2), soil evaporation compensation factor (ESCO), universal soil loss equation support practice factor (USLE_P) and initial organic nitrogen concentration in soil layer (SOL_ORGN) had significant effects on the SWAT outputs. The uncertainty analysis results showed that the uncertainty of runoff is the lowest, followed by TP and TN, and the uncertainty of sediment was the greatest. The kriging surrogate model has the ability to solve this time‐consuming problem rapidly with a high degree of accuracy, and thus it is very robust.