Z比分数-模糊AHP评价模型在卷烟成品实验室检测能力评价中的应用

为解决Z比分数法只能对卷烟成品实验室单个指标进行分析评价问题,将Z比分数、层次分析法(Analytic Hierarchy Process)与模糊综合评价法相结合,建立了Z比分数-模糊AHP评价模型。评价分为8个步骤:构建卷烟成品实验室评价指标体系,利用AHP确定各指标权重,将实验室每个样品的指标检测值转化为Z比分数(Z,ZB,ZW),利用模糊评价方法建立评语集和对应的分数集,把每个指标各样品Z比分数在评语集各等级所占比例作为隶属度,形成模糊判断矩阵,最终得到实验室物测、烟气以及综合检测能力评价得分及排序。以10个实验室为例验证了该模型的综合评价能力。结果表明,该综合评估方法适用于多样品和多指标的实验室比对综合能力评价,可以整体评价实验室物测、烟气和综合检测能力,并可分析查找存在问题的指标,为卷烟成品实验室的优化改进及提升检测能力水平提供了支持。      

比对试验中Z比分数法的应用比较

以棉花大容量纤维测试仪比对试验为例,通过分析、比较传统Z比分数法与最新的Z比分数法,得出最新的Z比分数法更能科学合理地评价实验室检测能力。     

水质中氟化物检测能力验证

目的：通过参与能力验证计划,收集客观、准确的证据,以证明实验室提供的数据可靠、有效,从而提升实验室的检测水平。方法：采用离子选择电极法-标准曲线法测定能力验证考核样品水质中氟化物的含量,对影响实验的各种因素进行质量控制。结果：本实验室氟化物实验室间Z比分数和实验室内Z比分数均为满意结果。结论：本实验室顺利通过了能力验证的考核,实验室对水质中氟化物含量测定的能力有效。     

实验室技术能力综合评价方法初步探讨

目的 探讨实验室技术能力综合量化分析评价方法.方法 利用国家食品安全风险评估中心组织的3次食品中重金属分析考核结果,比较了Z比分数方法、点分数法和组合分数法对考核的综合量化分析结果.结果 Z比分数法得到的5个考核目标物的满意率分别为78.1％、93.8％、81.2％、90.6％和93.8％;点分数法评价3次考核的满意率分别为75％、71.9％、90.6％;组合分数法评价3次考核各实验室综合表现满意率为81.2％.结论 3种不同评价方法各有侧重,适合于不同目的的结果分析.Z比分数法适用于单一因素分析能力评价;点分数法适用于一次多个因素分析能力综合性评价;组合分数法适用于实验室历次考核结果综合能力分析.     

茶叶中联苯菊酯、毒死蜱的测定能力验证结果与分析

目的通过参加能力验证实验,提高实验室农药残留检测的能力。方法优先选择本实验室常用方法,依据NY/T 761-2008、GB/T 23204-2008、GB 23200.13-2016方法,对样品进行相应的提取净化处理,随后根据相应的仪器进行定性定量检测分析,使用仪器比对、方法比对、人员比对、加标回收、质控样品作为质控方法。结果本次能力验证以NY/T761-2008报出检验结果。样品编号为18-U804检测结果为联苯菊酯:0.214 mg/kg, Z比分数为?0.4,毒死蜱为未检出;样品编号为18-Y023检测结果为联苯菊酯为0.582 mg/kg, Z比分数为?0.3,毒死蜱为0.364 mg/kg, Z比分数为?0.6,组织机构判定结果为满意。结论本次能力验证结果为满意,说明本实验室对农药残留的检测能力较好。     

土工膜拉伸强度的稳健统计分析

文章介绍了13家实验室参加土工膜拉伸强度检测能力验证的情况,在保证测试样品均匀性的前提下,采用迭代稳健统计技术对各实验室反馈的试验结果进行了分析,根据Z比分数值对各实验室检测能力进行了评价。     

棉花检测能力认证活动中统计模型的应用

在以往棉花检测能力认证的统计分析中,一般都采用Z比分数,但是Z比分数在参考值的选取以及分析方面存在一定的局限性.针对这一问题,选取灰色聚类分析方法,立足于三角白化权函数,以棉花的上半部平均长度等5个聚类指标,参加能力认证活动的14个实验室为聚类对象,将聚类对象划分为稳定性较好和一般2类.经过在棉花HVI能力认证活动中的理论和实验验证,灰色聚类分析方法可以作为类似能力认证活动的一个统计模型.     

肉糜中苯甲酸、山梨酸测定能力验证研究

目的评价检验机构对测定肉糜中苯甲酸、山梨酸的检测能力。方法对参加能力验证的88家实验室对苯甲酸和山梨酸的测定结果进行稳健统计分析,以Z比分数评价实验室检测能力。结果 88家实验室反馈了实验结果,满意率为77.3%。结论多数参加实验室对苯甲酸和山梨酸的检测结果达到了满意标准,得到不满意结果的实验室应查找自身原因并加以修正。     

采用稳健统计技术对纸张检测实验室测量误差分析及测量结果评价

制备纸袋纸纵向撕裂度分割水平检测样品,用单因素方差分析法对分割水平检测样品进行均匀性检验,将合格的检测样品发放给各比对实验室进行检测;采用稳健统计技术与Z比分数法,分析各实验室的检测结果,说明实验室间及实验室内的检测结果是否存在变异性,测量结果是否可靠;识别异常结果并找出影响检测结果可靠性的因素,从而使所有实验室的结果能趋于一致。分析结果表明,大多数实验室的检测结果是可靠和满意的,能够为科研单位和生产厂家提供较准确可靠的检测服务。     

食品多元素检测质控图及国际比对结果在质量控制中的应用

目的通过分析本实验室根据标准参考物测定结果绘制的质控图和2013年10月参加食品中多种微量元素含量测定的国际实验室间比对考核结果,探讨质控图及国际比对考核在实验室质量控制中的应用。方法以Z比分数法评价由国际原子能机构组织的食品中多种微量元素含量测定的国际比对结果,分析食品样品中多种微量元素的测定情况。结果绝大多数元素的考核结果|Z|1,结果优秀。结论质控图和国际比对实验研究是分析实验室质量控制的有效方法,应鼓励有条件的实验室更多地参与国际比对考核,以提高其检测能力及测定结果的可靠性。     

项目前期论证工作的组织与实施

项目前期论证工作是企业针对重大研发项目进行正确决策的关键环节。它包括寻找社会需要的产品 ,选择目标一致的合作伙伴 ,研究竞争对手 ,了解取胜市场所需的各种资源等 7项工作。具体实施过程中还要注意避免决策者的角色错误、过多顾及股东眼前利益、错误信息干扰等不利于正确决策因素的影响。新华公司在高强度低松弛预应力钢绞线、铝包钢丝两个项目中采取了一致的工作方法 ,均已获得了满意的回报     

QuEChERS-气相色谱-质谱法测定土豆中109种农药残留

建立土豆中109种农药残留的气相色谱-质谱(GC-MS)检测方法。方法 土豆样品以乙腈提取后,经N-丙基乙二胺(PSA)分散固相萃取净化(d-SPE),采用电子轰击电离源(EI)和负化学电离源(NCI)两种电离模式进行GC-MS测定。结果 各农药的定量限在0.001～0.010 mg/kg之间,对空白土豆样品的平均加标回收率为72.7%～118.7%,RSD在1.1%～17.3%之间。在EI模式下,土豆基质对绝大多数农药具有明显的基质效应,因此采用基质匹配标准曲线进行定量分析。应用此方法对欧盟农药残留参比实验室组织的国际比对考核的土豆样品进行定性筛查和定量测定,共检测出13种农药残留,含量范围在0.002～1.669 mg/kg之间,所提交的测定结果的Z评分值在-1.00～1.00之间。结论 本方法简便快速、准确、灵敏度高,适用于农产品中农药多残留的分析。     

基于高光谱图像分割的固态发酵中不同杆菌的识别方法

本文研究了基于高光谱图像分割的固态发酵中不同杆菌快速识别问题,实验采用马铃薯葡萄糖琼脂培养基对芽孢杆菌、乳杆菌、红螺菌样本进行制备,通过黑色镜头盖在镜头上获取全黑的反射图像,对图像进行去噪、分割处理,获取高光谱图像梯度及分布峰值,利用掩模图像中菌落所处位置对光谱数据信息进行提取,把获取的三种细菌的光谱数据分割成校正集与测试集,依次用于模型构建与验证。通过标准正态变量变化方法完成对原始光谱数据的预处理,利用主成分分析法进行降维处理并区分不同菌落,并采用偏最小二乘判别分析法建立识别模型,分析细菌高光谱图像和高光谱响应值主成分,建立并验证模型。结果表明,采用标准正态变量变化法进行预处理后,高光谱分析总误差与分析误差的比值是1.12,低于规定稳健性的参数;不同细菌菌落的高光谱波峰存在差异,对光的反射率也有较大不同;当培养时长为36h时,三种细菌可被有效区分;本文模型比其它两种模型更优,对测试集的识别率为98.25%。综上所述,采用本文方法具有分析误差低、识别率高的优点。     

Contamination of foods and feeding stuffs from selected areas of the Erfurt district with lead and cadmium. I. Determination of lead and cadmium in vegetable material by inverse voltammetry

An inverse voltammetric method is used for determining the trace elements lead and cadmium in vegetable foods and feeding stuffs. The organic meterials are mineralized by nitric acid vapour and, in the second stage, with the addition of perchloric acid. The procedure is very sensitive and suited for routine work. The detection limits are: 0.66 ng/ml for lead, and 0.30 ng/ml for cadmium. The error of the method is: VPb = 20.5% and VCd = 28.6%. The respective recoveries of amounts of lead and cadmium added to the samples prior to digestion were: 102.0 +/- 10.8% and 101.6 +/- 11.4%.     

Estimating dye concentrations in three-component wastewater by neuro-fuzzy technique

Several techniques have been suggested in the past to estimate the dye concentration in multiple-component solutions. This work explains new techniques based on adaptive neuro-fuzzy inference technique for measuring dye concentration in three-component wastewater solution. The performance of new method is compared with the normal Beer’s law. The mean ternary relative error in Beer’s law and neuro-fuzzy and PCA–neuro-fuzzy methods are 15.71, 6.044, and 5.814, respectively. The obtained results indicate that the performance of neuro-fuzzy technique is better than normal spectrophotometry method.     

微波真空干燥试验设备自动化监测系统的研究

微波真空干燥是综合微波干燥和真空干燥各自优点的一项新技术,微波真空干燥技术的特点非常适合食品的干燥生产。本文提供了一种新型的计算机自动监测手段,能够非常方便的在线测试物料实时的温度、重量、真空度,解决了在干燥过程中在线监测水分含量及物料内部温度这一难题;比较方便的在线记录和查询试验的数据和试验的结果,实现无纸记录,减轻了试验人员的工作量和人为误差。     

Method validation for the determination of total mercury in fish muscle by cold vapour atomic absorption spectrometry

A method was validated for the determination of total Hg in fish muscle using continuous flow cold vapour atomic absorption (CVAAS) after microwave digestion in closed vessels. The method was validated according to European Union Regulations 333/2007 and 657/2002, considering the maximum level for the metal in fish, established by European Union regulation 1881/2006. The procedure for determining linear range, selectivity, recovery, precision, trueness, decision limit (CCα), detection capability (CCβ), measurement uncertainty and robustness of the method is reported. The results of the validation process demonstrate the method fulfils the provisions of the Commission Regulation. The selectivity study indicated that there was no matrix effect on the calibration curve between the concentration range of 1.0 and 30.0 μg Hg l(-1). The mean recovery calculated at six levels of fortification was in the range of 94-104%. The limit of detection (LOD) and limit of quantification (LOQ) values were 4.90 and 15.7 μg kg(-1), while the CCα and CCβ values were 0.517 and 0.533 mg kg(-1), respectively, for the maximum contaminant level of 0.500 mg kg(-1). The relative expanded measurement uncertainty of the method was 0.055 mg kg(-1). The method was not affected by slight variations of some critical factors (ruggedness minor changes) as sample mass and volume of the HNO(3) and H(2)O(2) used in the digestion step. The method allowed accurate confirmation analyses of the CRM DORM 3. In fact, the Z-scores attained in a proficiency test round were well below the reference value of 2.0, proving the excellent performance of the laboratory.     

Real-time monitoring of alcalase hydrolysis of egg white protein using near infrared spectroscopy technique combined with efficient modeling algorithm

The degree of hydrolysis is one of the most important indexes for process control and quality assessment in proteins enzymatic hydrolysis. This article proposed a simple and rapid near infrared spectroscopy method for real-time quantifying the degree of hydrolysis in alcalase hydrolysis process. Efficient variables selection algorithms were systemically studied in multivariate calibrations; the partial least squares coupled with uninformative variables elimination and ant colony optimization were proposed for modeling with results yielding Rp = 0.9525. Additionally, 10 independent samples with the relative error less than 10% further confirmed the stability and reliability of this method. This work demonstrated that the near infrared spectroscopy technique with a selected multivariate calibration has a high potential for in situ monitoring of alcalase hydrolysis process in protein industry.     

European proficiency testing of national reference laboratories for the confirmation of sulfonamide residues in muscle and milk

Two interlaboratory studies were organized in 2002-2003 in order to check the proficiency of laboratories in confirming the presence of sulfonamide residues in muscle and milk. These studies involved 25 EU National Reference Laboratories (NRLs) from 21 different European countries in charge of statutory monitoring of antimicrobial residues in food of animal origin at a national level. The study was conducted according to international and national guidelines by the Community Reference Laboratory (CRL) in charge of antimicrobial substances. Four different test matrices of sheep muscle and four different test matrices of bovine milk containing different sulfonamide substances were prepared and sent to the participants. Each participant was asked to use his own routine confirmatory method and to analyse each sample in triplicate within a period of about six weeks during which the stability of the materials was checked by the organizer. The sulfonamide content of each material was determined by calculating the robust means of all the results and the deviation of the results from the assigned values was assessed by calculating Z-scores. Overall, results were satisfactory, particularly considering that it was the first proficiency test dealing with sulfonamides organised by the Community Reference Laboratory.     

Heat Transfer During the Freezing of Liver in a Plate Freezer

The overall heat transfer coefficient was determined for a vertical plate freezer by the transient temperature method and used in a modification of Plank's equation by Cleland and Earle to predict the freezing time of blocks of pig liver. A comparison of predicted and previously published experimental freezing times showed an average absolute error of 6.5%. Overall heat transfer coefficients for the main types of fibreboard packaging were also determined together with their effect on predicted freezing time. This work has highlighted many of the advantages of plate freezing which has yet to gain wide acceptance in the U.K. meat industry.