米香型白酒中乳酸乙酯内标法与外标法的比较

米香型白酒是以大米等为原料,经传统半固态发酵、蒸馏、陈酿、勾兑而成。具有以乳酸乙酯,β-苯乙醇为主体的复合香白酒。本文采用气相色谱法测定乳酸乙酯,并对内标法和外标法进行比较,结果表明两种方法的测量结果无显著差异,且外标法有着用时短,操作简单的优势,便于满足现代快速分析要求,因此可将其应用到米香型白酒乳酸乙酯日常分析检测中去。     

要将众望所归的好事尽快办好——评白酒国家卫生标准取消杂醇油指标及其他

1GB2757—1981《蒸馏酒及配制酒卫生标准》于2006年底发布了第2号修改单,取消杂醇油指标。这是众望所归的一件好事广西生产的白酒主要是米香型白酒,其中最有名的是桂林三花酒和湘山酒。米香型白酒的一个特点是杂醇油含量较其他香型白酒高。过去不少     

高效液相色谱法测定绝缘油中糠醛含量的不确定度评定

绝缘油中的糠醛含量能够评估变压器绝缘纸的老化状况,并反映其绝缘性能.通过高效液相色谱法对绝缘油中糠醛含量进行定量分析,建立数学模型,确定测定结果的不确定度来源为糠醛标准物质、标准油液的配制、标准曲线的拟合、样品制备、回收率、测量重复性,并对测试结果进行不确定度评定.实验结果表明,绝缘油中糠醛样品浓度为1.05 mg/k...     

高效液相色谱法测定白酒中糖精钠的方法探讨

主要参照GB 5009.28—2016标准,从三个方面:改变流动相配比、改变色谱柱和改变液相色谱的检测器,运用高效液相色谱法将白酒中存在的干扰糖精钠检测的物质:糠醇、糠醛得以分离,以达到对白酒中糖精钠准确测定的目的。     

火焰原子吸收光谱法测定白酒中铅、铁、铜、锰4种微量重金属元素

正在GB/T5009.48-2003《蒸馏酒与配制酒卫生标准的分析方法》中要求采用GB/T5009.90-2003《食品中铁、镁、锰的测定》和GB5009.12-2010《食品安全国家标准食品中铅的测定方法》测定白酒中金属成分,两种方法均为传统湿法消化法测定食品中重金属含量,污染较大,时间较长。本文利用原子吸收分光光度计对白酒中铅、铁、铜、锰进行检测,通过白酒除醇与水定容、白酒除醇消解与水定容、白酒除     

饮料酒中β-苯乙醇标准物质标准浓度的测量不确定度评定

β-苯乙醇是一种具有玫瑰花香、蜜香的高级醇,是饮料酒中重要的高沸点香气成分,其在黄酒、日本清酒、啤酒、白酒中均有不同的含量,在中国黄酒中β-苯乙醇更具有较高的香气强度.国家标准GB/T10781.3-2006《米香型白酒》、GB/T16289-2007《豉香型白酒》、GB/T13662-2008《黄酒》,轻工行业标准QB/T2746-2005《清爽型黄酒》,以及地方标准DB52/535-2007《贵州米酒》等均对β-苯乙醇提出了控制性技术指标.因此,研制一种可溯源并附有标准值的β-苯乙醇标准物质,对于指导该类酒的生产,控制产品质量具有重要意义.     

饮料酒中β-苯乙醇标准物质标准浓度的测量

β-苯乙醇是一种具有玫瑰花香、蜜香的高级醇,是饮料酒中重要的高沸点香气成分,其在黄酒、日本清酒、啤酒、白酒中均有不同的含量,在中国黄酒中β-苯乙醇更具有较高的香气强度。国家标准GB/T10781.3-2006《米香型白酒》、GB/T16289-2007《豉香型白酒》、GB/T13662-2008《黄酒》,轻工行业标准QB/T2746-2005《清爽型黄酒》,以及地方标准DB52/535-2007《贵州米酒》等均对β-苯乙醇提出了控制性技术     

全自动流动注射分析仪和紫外分光光度计法测定白酒氰化物的比较研究

本研究从标准曲线线性、方法检出限、定量限、回收率、精密度、工作效率、方法适用性等方面,对比了全自动流动注射分析仪和紫外分光光度法测定白酒氰化物的方法.全自动多参数流动注射分析仪r2=0.9999,紫外分光光度计r2=0.9998,在0～100μg/L浓度范围,两种方法的相关性没有明显差异.全自动流动注射分析仪方法检出限...     

白酒调整国标低度市场看好

从3月份开始，国家白酒行业标准将进行新的调整，现行白酒行业各种香型高、低度酒的两个标准将合并为一项标准，成为白酒业首个全国通用的国家标准。新的标准将产品分为高度酒和低度酒，同时对白酒的酒精度和质量等级进行调整，扩大低度酒的空间。     

电晕探测中的紫外对焦控制系统

本文简要介绍了电晕探测的原理,采用可见光与紫外双光谱探测方法来检测电晕信号的存在并对其进行定位.文中介绍了电晕探测系统紫外对焦控制模块,并阐述了对焦的双闭环控制过程及其软硬件实现方法.分析了对焦控制过程中误差产生的原因,主要包括传动机构的空回及系统的过冲量.通过实验测量得到传动机构的空回和过冲量,将其加入紫外对焦过程的总对焦量.采用上述方法可以减小紫外对焦系统的对焦误差,使紫外相机像面始终处于焦深之内.最后,利用电晕探测系统对高压电厂中的电晕信号进行检测并定位.     

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.     

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.     

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.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。