顶空气相色谱外标法测定血液中乙醇含量的不确定度评定

目的:建立顶空气相色谱外标法测定血液中乙醇含量不确定度评定方法。方法:用顶空气相色谱法测量血液中乙醇含量,对过程中所涉及的各不确定度分量进行分析,评定测量值的不确定度。结果:血液中乙醇含量为1.95mg/m L,扩展不确定度为0.02 mg/m L。结论:各不确定度分量对评定结果影响轻微。     

台式密度计酒精浓度校准方法探讨

一、引言目前台式密度计依据JJG1058-2010《实验室振动式液体密度计检定规程》仅能对密度模式校准,而不能校准酒精浓度,无法满足实际需求。基于JJF1074-2001《酒精密度-浓度测量用表》,本文提出一种配制酒精浓度标准液对仪器进行校准的方法。通过纯水和乙醇配制体积百分浓度q为0%~100%的溶液,将溶液在经检定后的台式密度计上测定密度值,由测量用表线性插值将密度值转换为对应的酒精浓度标称值。     

酒精计修正值的不确定度评定

浮计检定采用直接比较法,将二等标准酒精计与被检酒精计同时浸入同一检定液中,直接比较它们标尺的示值,从而得到被检酒精计的修正值。影响酒精修正值的不确定度因素有二等标准酒精计组、被检酒精计读数、检定液体毛细常数变化、被校干管不垂直及分度线倾斜、测量重复性。本文通过对这几方面的分析,从而评定酒精计修正值的不确定度,对日后的计量检定提供一些参考。     

血液中乙醇含量测定内标法和外标法不确定度的比较

目的:为了评定和比较顶空-气相色谱法测定血液中乙醇含量进行内标法和外标法的不确定度。方法:分别从内标法和外标法测定程序分析了不确定度的来源,对各分量进行量化后计算出合成标准不确定度和扩展不确定度。结果:内标法测定血样中乙醇含量的平均值为0.793mg/m L,扩展不确定度为0.058mg/m L;外标法测定血样中乙醇含量的平均值为0.812mg/m L,扩展不确定度为0.060mg/m L。结论:内标法和外标法定量的不确定度主要均来源于重复平行测定的误差,得出的测量不确定度反映出两种检测方法无明显差异。     

连续流动注射法测定地表水中阴离子表面活性剂方法改进

改进了流动注射分析法测定地表水中阴离子表面活性剂(十二烷基硫酸钠)的方法，并对其中吸附剂、吸附剂浓度、反应环境p H值和反应时间等实验条件进行优化研究。研究结果显示，当吸附剂为Co-5-Cl-PADAP、浓度为1.0×10^-5mol/L、反应p H值6和反应时间20min时，测得吸光度较稳定。该方法具有良好的准确度和精密度。方法标线方程为y=0.95×10^-1x+2.61×10^-5，相关系数r=0.9996，方法检出限0.0013mg/L。标准偏差RSD 1.25%～3.80%之间，该方法优于国标的亚甲基蓝法分光光度法(GB7494-87)。实样测试中，加标回收率范围98.2%～103.5%。该方法可以良好地应用于地表水的十二烷基硫酸钠中，具有一定的推广应用价值。     

离子色谱法标定盐酸标准滴定溶液浓度

盐酸标准滴定溶液按照国标方法要求制备,稀释1000倍,注入离子色谱柱,0.8mmol/L NaHCO3+4.5mmol/L Na2CO3淋洗液等度淋洗,流速1.0ml/min,抑制电导检测Cl-浓度,保留时间定性,外标法峰面积定量,标准曲线上给出的Cl-质量浓度换算成盐酸标准滴定溶液的摩尔浓度。在1.0-50.0mg/L范围内,Cl-浓度与色谱峰面积呈良好的线性关系(R2=0.9997),加标回收率为98.63%-101.22%,方法精密度RSD0.70%,经t检验与国标法标定盐酸标准滴定溶液摩尔浓度无显著性差异。该方法简便快速、价廉、无干扰、灵敏度高,标定结果准确度、精密度高,节省人力物力,适合在具备离子色谱仪的检测实验室代替容量法标定盐酸标准滴定溶液摩尔浓度。     

精密酒精计的不确定度及符合性评定

本文分析了影响酒精计修正值的不确定度因素,主要包括:测量重复性、二等标准酒精计的示值、二等标准酒精计的修正值、被检酒精计示值、环境温度、液体毛细常数变化、表面张力、空气浮力、垂直偏差和数据修约,从而评定精密酒精计修正值的不确定度,对白酒企业中的科学计量、理化检测和数据分析提供参考依据。     

精密酒精计的不确定度及符合性评定

文章分析了影响酒精计修正值的不确定度因素,主要包括:测量重复性、二等标准酒精计的示值、二等标准酒精计的修正值、被检酒精计示值、环境温度、液体毛细常数变化、表面张力、空气浮力、垂直偏差和数据修约,从而评定精密酒精计修正值的不确定度,对白酒企业中的科学计量、理化检测和数据分析提供参考依据。     

肉苁蓉中多酚类物质提取条件的优化及含量的测定

本研究建立了紫外-可见分光光度法测定肉苁蓉中多酚类物质(以没食子酸计)含量的方法。当乙醇浓度为70%、温度为60℃、提取时间为30min、料液比为1:20时,肉苁蓉中多酚类物质(以没食子酸计)的提取效果最好。同时肉苁蓉样品中多酚类物质(以没食子酸计)的平均质量百分比为0.2422%。精密度、稳定性和加标回收结果显示该方法可行可靠。     

绿藻生物质发酵生产燃料乙醇的研究

主要探讨了利用绿藻作为生物质原料进行乙醇发酵的可行性及其发酵效果,考察了不同种类绿藻、硫酸浓度以及钠离子浓度对乙醇产量的影响。研究结果证明石莼葡萄糖含量丰富,作为发酵乙醇的原料是十分有潜力的。预处理过程中最适硫酸浓度为2%,并利用氢氧化钙调节p H值为5.5时,其最大乙醇浓度可高达30 g/L,且产乙醇速率可达0.63 g/(L·h),乙醇产量为37 g/kg。在酶解存在的条件下,加大硫酸浓度水解对绿藻中葡萄糖的溶出并没有很大帮助,主要影响其它五碳糖的溶出。钠离子对发酵产乙醇过程的影响较大,钠离子浓度过高会抑制乙醇产量以及产乙醇速率;而在氯离子存在的条件下,低钠离子浓度便可对乙醇发酵产生严重抑制。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.