汽油二烯值的测量不确定度评定

根据国家计量技术规范JJF1135-2005《化学分析测量不确定度评定》,评定了电位滴定法测定汽油中二烯值含量的不确定度。其来源主要包括称量的不确定度、标准溶液的不确定度及测量重复性引入的不确定度等,将各不确定度分量合成后,得到汽油二烯值的不确定度为:当二烯值含量为0.35 gI2/100 g时,扩展不确定度为0.03 gI2/100 g,结果表达式为(0.35±0.03)gI2/100 g(k=2)。     

EDTA滴定法测定石灰石中氧化钙含量不确定度的评定

对EDTA滴定法测定石灰石中氧化钙含量进行了不确定度评价。分析了整个测试过程中不确定度的来源,并对各个不确定度分量进行了计算。结果表明,EDTA滴定法测定石灰石中氧化钙实际标准含量的差异,主要存在于标定溶液测定的数据值与样品测定值的偏差。当测定石灰石样品中氧化钙质量分数为51.73%时,其扩展不确定度为0.20%(k=2)。     

电位法测定茶园土壤pH值的不确定度评定

采用电位法对茶园土壤的pH值进行测量,评定测量不确定度。建立数学模型,分析不确定度来源,计算不确定度分量并合成。茶园土壤pH值不确定度评定结果为pH=4.06±0.09,p=95%,k=2。不确定度主要来源于水体积,其次为标准溶液和pH仪。使用高精密度的量器和仪器,选择高纯度的标准物质,增加重复测量次数,可减小不确定度。     

埋地塑料管道覆土深度的设计探讨

针对埋地塑料管道的特点,结合工程实例,通过计算探讨了由管壁环向强度验算确定压力流管道覆土深度的重要性,并对稳定计算中管壁截面失稳的Fcr,k值计算式的应用效果提出了看法,认为压力流埋地塑料管道应通过计算确定覆土深度,用《给水排水塑料管道设计施工手册》提出的Fcr,k计算式,其计算结果与工程实况一致。     

全自动色差计对龙泉青瓷色度测量及不确定度评定

分析了全自动色差计测定龙泉青瓷色差引起不确定度的各分量来源,对其不确定度进行了合理的评估。结果表明,取置信概率p=95%,包含因子k=2,龙泉青瓷色度刺激值扩展不确定度U(Y)为2.12,色品坐标扩展不确定度U(x)、U(y)分别为0.0022、0.0022。评定结果表明,仪器示值误差引入的不确定度贡献最大。     

化妆品中石棉定量分析不确定度评定

为了准确对化妆品石棉定量分析过程中的不确定度进行评定,开展了化妆品中的石棉含量不确定度评定。根据X射线衍射定量分析的基本理论,本文建立了石棉K值、石棉含量计算的数学模型,分别识别了不确定度分量的来源,并计算各不确定度分量的灵敏系数,通过对不确定度分量的合成,最终得到石棉含量为1.27%时,其扩展不确定度为0.042%(k=2)。研究成果对使用其它X射线衍射定量分析方法进行定量分析不确定度评定也具有指导意义。     

试值代入法计算盐水溶液的pH值

采用新的思路在已知平衡常数时计算pH值.视pH值为已知值、某一平衡常数k为未知值,试选pH值代入计算k的试算值,选取最接近实际平衡常数的试算值所对应的pH值作为计算结果.以此方法使用电子表格实现了对多元弱酸盐、酸式盐和部分同多酸盐水溶液pH值的计算.     

水热条件下纳米级球状羟基磷灰石的制备

本文以Ca(NO3)2.4H2O和(NH4)2HPO4为原料水热条件下合成了羟基磷灰石晶体。研究了水热温度,保温时间,pH值,溶液浓度对合成羟基磷灰石晶体的影响,并借助X射线衍射(XRD)、红外吸收光谱(FT-IR)、扫描电子显微镜(SEM)对合成的羟基磷灰石进行了物相组成、化学组成、微观形貌的研究。结果显示,pH值对合成羟基磷灰石形貌有决定性的影响,调节pH值为5、7、8、9、10,羟基磷灰石形貌经历了长棒状、短棒状、球状的变化。确定pH值为10,正交试验研究其它三个因素对球状羟基磷灰石粒径的影响,三因素影响顺序依次为:初始溶液浓度>保温时间>水热温度。正交试验同时得到合成粒径小活性高的HA晶体的最佳工艺条件组合为:k2k1k3,即水热温度为140℃,保温时间为1 d,初始溶液浓度为0.5 mol/L。     

原油残炭测定的不确定度评定

本文选取中缅管输原油作为试验样品,采用微量法对其进行残炭的测定,并对残炭值的不确定度进行分析及研究。结果表明,残炭称量引入的不确定度最大,当原油的残炭值为5.747%时,其合成不确定度为0.085%,扩展不确定度为0.170%(k=2),测定结果为（5.747±0.170）%。在残炭称量的过程中,可选用高精密度的天平,并保持使用实验器具的干燥清洁,提高操作人员的检测水平和熟练度,以减少称量过程产生的误差,降低不确定度。     

水焓值法制冷量源装置的计量特性

水焓值法制冷量源能够应用于制冷量的量值传递,提供数值可测、可控的制冷量量值。首先提出了水焓值法制冷量源原理,并在该原理基础上设计和研制了制冷量源装置的物理结构。然后在空气焓值法实验室中对制冷量源进行了实验测量,由风机功率转化实验结果可知风机消耗功率完全转化为空气焓值的增加,并可通过焓差室测量。最后对制冷量源装置进行了稳定性研究和不确定度评定,由实验结果分析可知稳态运行30 min输出制冷量标准差为22.2 W（制冷量5251.9 W）,相对扩展不确定度为0.6%（k=2）。水焓值法制冷量源装置第一次从计量学角度实现了制冷量量值的溯源,输出量值可溯源至温度、压力、流量和电功率。     

Determination of the quality and purity characteristics of olive oils obtained from different regions of Turkey,depending on climatic changes

Virgin olive oils (VOOs) obtained from olives grown in different regions of Turkey under changing climatic conditions sometimes show different sensory and chemical properties. This study was planned to determine whether these deviations are due to climatic changes or not. For this purpose, five different olive varieties (Ayvalık, Memecik, Gemlik, Nizip Yağlık, Kilis Yağlık) of commercial importance were harvested from the provinces/districts (four different region) where cultivation is intense during the 2017/2018–2020/2021 harvest years. Every year, olive samples were collected from 3 orchards from 13 provinces/districts. One hundred and fifty-six samples were subjected to the purity, quality and sensory analysis. Basic climatic values (average, minimum and maximum temperature, humidity and precipitation) were examined for four consecutive years. All of the examined olive oil samples were determined within the legal limits in terms of fatty acid composition and fatty acid ethyl ester values. However, delta-7-stigmastenol value from the sterol composition was found to be above 0.5% in some samples in all the years studied (total 21 samples). Delta-7-stigmastenol values of olive oil samples varied between 0.16% and 1.14%. Multiple linear regression analysis was applied using a genetic algorithm-based inverse least squares method to determine whether there is a relationship between climate data and delta-7-stigmastenol values. According to this result, it has been determined that the delta-7-stigmastenol value is high when the annual average relative humidity is low and the annual average temperature is high. There is an urgent need to make forward-looking plans due to climate change.     

The second virial coefficients of highly-purified ring polystyrenes in cyclohexane

The second virial coefficients A₂ of ring polystyrenes with high purity in cyclohexane were measured by light scattering in the temperature range 27.0-34.5 °C. The purity of four samples with M_w of 16k, 42k, 110k and 570k was determined to be all over 96% by HPLC. It has been found that A₂s of all the samples are definitely positive at the theta temperature of linear polystyrene, 34.5 °C, and the measured values for four samples converged to zero at 27.7 °C with decreasing temperature. This value is below the previously reported one, but it is quite consistent with the predicted value based on the topological repulsive interaction among the ring polymer molecules.     

VPO测定EO–THF共聚醚_n影响因素

采用蒸气压渗透法(VPO),通过研究仪器常数k值的测定、样品的水含量、试样溶液的浓度、稳定时间等因素对端羟基环氧乙烷–四氢呋喃(EO–THF)共聚醚数均相对分子质量(n)测定稳定性的影响,确定了测试条件。结果表明,采用八乙酰蔗糖为标准物质,三氯甲烷为溶剂,试样浓度在6～30 g/kg进行仪器常数k值的测定,可有效提高VPO测定EO–THF共聚醚n的稳定性。此外,EO–THF共聚醚样品的n分布及其含水量对测定n结果也产生较大影响。     

Effect of temperature on the rates of dissolution of gibbsite and boehmite

The effect of temperature on the rate of dissolution of gibbsite and boehmite in caustic soda solutions was studied in the temperature range 25-100°C. The results fitted the Arrhenius rate equation and the activation energy was found to be 30.6 ± 0.9 k. cal/g-mole for the gibbsite reaction and 29.4 ± 1.3 k. cal/g-mole for the boehmite reaction. While the effect of temperature on the boehmite dissolution has not been reported before, the value of the activation energy for gibbsite was higher than previously reported values. Reasons for these differences are given and a consistent value of the activation energy was obtained which agreed both with experimental data for different gibbsite samples and with modified forms of the previously published data.     

The effect of unit k/s calculation and spectral overlapping on the performance of color matching

There are several approaches to dyeing recipe formulation in the textile industry, because the accuracy of computer recipe prediction is not very high. There are several theories such as colorimetric and spectrophotometeric appraches on color reception. This work addressed the effect of the calibration method as the calculation of unit k/s and spectral overlapping of the components of the mixture on the accuracy of recipe prediction in dyeing nylon with acid dye. To this aim, the unit k/s was calculated using single and binary mixture samples. Two types unit k/s were used for the recipe prediction of ternary mixture dyed samples with low and high overlapping reflectance spectra. The obtained results indicated that the unit k/s of single component differed from the unit k/s of bicomponent mixture. The accuracy of recipe prediction using unit k/s of single component was less than that of the binary mixture. However, the performance of the recipe prediction of high level overlapping was found to be more than that of the low level overlapping mixture. Subsequently, the accuracy of color matching depended on the reflectance spectra similarity (spectral overlapping) of the components of the mixture.     

Magnetic and dielectric properties of magnesium substituted cobalt ferrite samples synthesized via one step calcination free solution combustion method

Magnesium substituted cobalt ferrite samples were prepared using solution combustion synthesis without any post-heat treatment. Structural characterization confirms the pure spinel phase with high crystallinity. The cation distribution of the samples was calculated using the value of lattice parameter obtained from Rietveld refinement. Hard to soft magnetic transition was observed as magnesium progressively replaces cobalt in spinel phase. Dielectric properties exhibit a behaviour which is similar to what has been reported for spinel ferrite family. This behaviour could be explained by a Maxwell–Wagner interfacial type polarization.     

微机型综合保护装置整定值计算

介绍了微机型电动机速断保护装置的整定值计算。给出了计算保护定值的公式 :(1)在采用正序电流及全电流加延时的情况下 ,Idz=KkKjIqd/Ne ;(2 )在采用全电流无延时的情况下 ,Idz=KdKkKjIqd/Ne。分析了微机型变压器过流保护装置的特性 ,介绍了计算过流定值的方法和灵敏度检验以及计算实例。     

水热法合成纳米CdWO_4及其光催化性能研究

通过水热法合成光催化性能良好的纳米CdWO_4。采用粉末X射线衍射、扫描电子显微镜研究溶液pH值及水热温度对CdWO_4微观形貌、晶体结构的影响。在紫外线光照下甲基橙降解实验中测试制备的CdWO_4纳米颗粒的光催化活性。结果表明,合成的催化剂为单斜晶系CdWO_4晶体,不含其他杂质。水热反应温度150℃时,随着溶液pH值的降低(10.0→9.20→8.60),CdWO_4颗粒逐渐减小,紫外光照射90 min后,甲基橙降解率分别为20%、 26%和40%,其降解动力学参数k分别为0.002 3 min^(-1)、0.003 3 min^(-1)、0.005 7 min^(-1)。水热反应温度升高至180℃,pH为8.60时,合成的CdWO_4催化剂呈细针状,具有最高的光催化活性,光照90 min后,甲基橙降解率70%,降解动力学参数k=0.026 2 min^(-1)。     

非离子表面活性剂聚乙氧基衍生物-羟值的分析

本文报导了非离子表面活性剂聚乙氧基衍生物-羟值的一种新的分析方法.该方法突出的优点是短时间完成分析全过程,并获得与常规乙酸酐同样的分析效果,与标准样品进行比较实验,分析准确率可达98%以上.     

微乳法制备棒状ZnO材料及其光催化性能

采用浊度法绘制十六烷基三甲基溴化铵(CTAB)/正丁醇/环己烷/硝酸锌或草酸铵水溶液体系的拟三元相图,确定微乳液稳定区域最大时CTAB与正丁醇的质量比为1∶1。在此条件下,选择m(CTAB+正丁醇)∶m(环己烷)=3∶7,以硝酸锌和草酸铵为原料,采用微乳法制备ZnO的前驱体二水合草酸锌,然后通过煅烧得到ZnO样品。考察水与CTAB的摩尔比(R)和反应物浓度对ZnO材料结构、形貌、光学性质和光催化性能的影响。实验结果表明:ZnO样品为纯的六方纤锌矿结构晶体,形貌均为棒状,且样品的尺寸随R值和反应物浓度的不同而不同。在300 W汞灯紫外光照射下,ZnO样品对亚甲基蓝溶液均具有较好的光催化性能,光催化反应过程符合准一级反应动力学。其中,在反应物浓度为0.15 mol/L,R=15条件下制备的ZnO样品在光照90 min时可使亚甲基蓝的降解率达到97.0%,且降解反应速率常数k最大,其光催化性能最好。