气相色谱法测定邻苯二甲酸酐纯度的测量不确定度评定

按照GB/T 15336-2013《邻苯二甲酸酐》,用气相色谱法测定邻苯二甲酸酐的纯度并建立数学模型,对测定过程中影响检测结果的各不确定度来源进行分析和评定。通过计算重复性、样品质量、溶剂体积、响应因子等因素带来的不确定度,得到邻苯二甲酸酐纯度测量结果的合成不确定度。实验结果表明,不确定度的主要影响因素为溶剂体积,其次为响应因子和样品质量。通过对不确定度进行评估,有利于提高检测结果的可靠性,可以为准确测定邻苯二甲酸酐的纯度提供理论依据。     

超高效液相色谱质谱法测定水产品中恩诺沙星含量的不确定度评价

采用超高效液相色谱质谱法测定水产品中恩诺沙星的含量,分析不确定度的来源,建立评估的数学模型,通过计算不确定度的各主要分量,给出了测定结果的扩展不确定度.评定结果表明:影响检测结果不确定度的主要因素为标准溶液的配置、样品的回收率和测量重复性等.     

电感耦合等离子体原子发射光谱法测定银中硒、碲含量的不确定度评定

采用电感耦合等离子体原子发射法测定银中的硒、碲含量,对测定结果的不确定度进行评定.通过对测量过程中测量重复性、标准曲线变动性、试液体积、试料质量、标准溶液浓度和移取体积等影响因素进行分析,结果表明,测量重复性和标准曲线变动性对总不确定度影响较大.因此,在测定中应适当增加样品和标准溶液重复测定次数,不断优化仪器参数,准确...     

食品中过氧化值含量测定的不确定度评定

通过对检测过氧化值含量的整个过程进行不确定度分析,找出引起不确定度产生的因素.评定确认滴定体积是影响结果的最主要因素.测量重复性引入的不确定度也应引起重视.此方法对类似滴定法测定物质含量的不确定度评定有借鉴和参考作用.     

凯氏定氮法测定大豆粉中蛋白质的不确定度评定

通过对凯氏定氮法测大豆粉中蛋白质含量的测定过程的研究,确定测定结果的不确定度。建立不确定度的数学模型,对各不确定度分量进行合成和扩展,最终建立大豆粉中蛋白质的不确定度评定方法。影响测量结果不确定度的因素共有5项,按其影响大小顺序排列分别为测量重复性、试样质量、样液滴定体积、样液移取体积以及盐酸标准溶液浓度。其不确定度报告为大豆粉中蛋白质含量为:(39.0±0.6)g/100g,包含因子k=2。     

原子吸收光谱法测定铍中铜含量的不确定度评定

采用原子吸收光谱法对铍中铜元素含量进行测定,分析了影响测量不确定度的主要因素,通过建立测量过程中各分量不确定度评价的数学模型,对试料称量、溶解、萃取、标准溶液配制、工作曲线拟合、样品重复性测量等影响不确定度的分量进行分析,最终合成得到了测量结果的扩展不确定度。结果表明,样品重复性测量、工作曲线拟合是影响原子吸收光谱法不确定度的主要因素,从而为采用原子吸收光谱法测定铍中铜含量的检测质量控制提供理论基础。     

粘土砖体积密度测定的不确定度评定

按致密定形耐火材料制样及体积密度检验方法标准,取具有代表性的一块粘土砖样品,对影响其体积密度测定的不确定度因素进行了分析,且对影响其体积密度测定不确定度的各个分量进行计算和合成,给出了该粘土砖不确定度的报告;通过评定其体积密度的不确定度,了解到影响该粘土砖的不确定度的主要因素为重复性试验(包括制样及检测)。     

微波消解ICP-MS法测定化妆品中镉的不确定度评定

本文采用微波消解-电感耦合等离子体质谱法(ICP-MS)测定化妆品中镉,通过创建数学模型结合评估的方法,分析影响不确定度的主要来源,对样品检测过程中影响不确定度的分量:样品称量、定容体积、标准溶液的配制、曲线拟合、仪器测量重复性和加标回收率等进行分析,按JJF 1059.1—2012《测量不确定度评定与表示》的规定进行合成,最终计算出镉的扩展不确定度,为系统分析检测结果的准确度和方法的可靠性提供参考,使实验结果更具客观性和准确性。     

微波消解ICP-MS法测定化妆品中砷的不确定度评定

采用微波消解-电感耦合等离子体质谱法（ICP-MS）法测定化妆品中砷,通过创建数学模型并选择评估的方法,分析了影响测量不确定度的主要来源,对样品消解过程中的样品称量、消解、定容体积、测定过程的标准溶液的配制、曲线拟合、仪器测量重复性等影响不确定度的分量进行分析,按JJF1059-1999《测量不确定度评定与表示》[1]的规定进行合成,最终计算出砷的扩展不确定度,为系统分析检测结果的准确程度和方法的可靠性研究提供参考,使实验结果更具客观性和准确性。     

火焰原子吸收分光光度法测定低合金钢中镍含量的不确定度评价

依据GB/T 223.54—1987利用火焰原子吸收分光光度法对低合金钢中镍进行了测定,对测定过程中不确定度的来源进行了分析,并对测定过程中的不确定度分量进行了合理评定,评定了测量结果的不确定度。找出了影响检测的主要因素,测量不确定度主要来源于试样称量、试样溶液定容和试样溶液质量浓度测定三方面,试样溶液质量浓度上机测定引入的不确定度主要来源于校准溶液配制、校准曲线拟合及重复性测定等,通过分析,明确了提高测量准确度的方法,给出了评定方法、步骤及结果。     

FR型专用复合蜡在粉状乳化炸药中的应用?

以含蜡馏分油为原料,添加FR专用乳化剂和其他添加剂,利用均匀设计技术进行配方优化试验,着重考察复合蜡的滴点、黏度、含油量对粉状乳化炸药储存稳定性及抗水性的影响。试验结果表明,复合蜡适宜的滴点为70~85℃,适宜的黏度为75~85 mm2/s,适宜的含油量(质量分数)为20%~30%。通过工业应用试验结果表明,以FR型专用复合蜡为油相材料生产的粉状乳化炸药,爆炸性能满足WJ9025—2004岩石粉状乳化炸药标准的要求,可完全替代T-155、石蜡和微晶蜡等油相材料。     

乳化炸药复合蜡含油量测定方法分析

含油量对乳化炸药复合蜡的强度、硬度、柔软性、滴熔点等物理性质有很大影响,从而影响乳化炸药的流动性及储存性能。蜡类含油量测定有丁酮-甲苯法(石化行业标准)与丁酮法(国家标准)。采用这2种方法对样品蜡含油量进行测定和分析,结果表明,不同方法的测定结果差别大,测定乳化炸药复合蜡含油量推荐采用丁酮-甲苯法,丁酮-甲苯作溶剂的NB/SH/T 0556—2010《石油蜡溶剂抽出物测定法》是最适宜的乳化炸药复合蜡含油量测定方法。     

Comparison of microstructural and physical properties of two petroleum waxes

Microstructural and physical properties of two petroleum waxes, petrolatum and microcrystalline wax, were characterized in this work. Petroleum waxes are known to be hydrophobic and can be used in applications where a good moisture barrier is needed. In order to achieve a better understanding of different inherent properties of a wax, the two waxes in this work were characterized with infrared spectroscopy, confocal laser scanning microscopy, differential scanning calorimetry, rheology and X-ray diffraction. It was concluded from the results of infrared spectroscopy that the two waxes consisted only of saturated alkanes. Confocal laser scanning microscopy showed that the petrolatum sample had a more open microstructure with coarse crystals separated from each other than the microcrystalline wax, which appeared to have a more network-like crystalline structure consisting of somewhat finer crystals. Both waxes crystallized over a broad temperature range. Their crystallization characteristics were quite different, however, probably owing to a different oil content. According to modulated differential scanning calorimetry and rheological measurements the microcrystalline wax crystallized through a two-step process, whereas the petrolatum crystallized through only one step.     

Thermal Treatment of Beads with Wax for Controlled Release

Beads prepared by extruder/marumerizer technology were formulated with water soluble drugs, microcrystalline cellulose and several waxy materials. The waxes (10 to 50% by weight) were included in an effort to slow drug release. Subsequent thermal treatment of these beads was applied. Beads were processed to determine the effect of varying wax level, excipient, active drug, and effect of heat treatment. In-vitro drug release profiles were evaluated for the untreated and thermal treated beads. In general, the simple incorporation of wax into the granulation did not provide the desired controlled release dissolution profile. Thermal treatment of the finished beads, however, resulted in products which behaved in a different manner during dissolution testing and in general provided slower release. Drug release was found to vary with the type and level of wax, drug, excipient, and the thermal treatment.     

一种低表面能氟硅改性环氧涂层对北原油的防结蜡效果

油田管道防结蜡用单一树脂涂层的附着力、硬度及耐蚀性较差.采用低表面能氟硅改性环氧涂层,并进行防结蜡试验研究,对影响结蜡的因素进行考察,并对防结蜡效果进行评价.结果表明:氟硅改性环氧涂层的防结蜡效果明显优于市售某低表面能涂料涂层;当氟硅聚合物(FS-1)含量5％时,在原油搅拌速度600 r/min,油温40℃,壁温25 ℃条件下,氟硅改性环氧涂层对七里村和英旺原油防结蜡率分别为69.2％和66.8％,而某市售涂料涂层防结蜡率仅为47.1％和45.8％.     

Thermal Treatment of Beads with Wax for Controlled Release

Abstract

Beads prepared by extruder/marumerizer technology were formulated with water soluble drugs, microcrystalline cellulose and several waxy materials. The waxes (10 to 50% by weight) were included in an effort to slow drug release. Subsequent thermal treatment of these beads was applied. Beads were processed to determine the effect of varying wax level, excipient, active drug, and effect of heat treatment. In-vitro drug release profiles were evaluated for the untreated and thermal treated beads. In general, the simple incorporation of wax into the granulation did not provide the desired controlled release dissolution profile. Thermal treatment of the finished beads, however, resulted in products which behaved in a different manner during dissolution testing and in general provided slower release. Drug release was found to vary with the type and level of wax, drug, excipient, and the thermal treatment.     

Effect of diluents on tablet integrity and controlled drug release

The objective of this study was to evaluate the effect of diluents and wax level on tablet integrity during heat treatment and dissolution for sustained-release formulations and the resultant effect on drug release. Dibasic calcium phosphate dihydrate (DCPD), microcrystalline cellulose (MCC), and lactose were evaluated for their effect on tablet integrity during drug dissolution and heat treatment in wax matrix formulations. A newly developed direct compression diluent, dibasic calcium phosphate anhydrous (DCPA), was also evaluated. Compritol® 888 ATO was used as the wax matrix material, with phenylpropanolamine hydrochloride (PPA) as a model drug. Tablets were made by direct compression and then subjected to heat treatment at 80°C for 30 min. The results showed that MCC, lactose, and DCPA could maintain tablets intact during heat treatment above the melting point of wax (70°C-75°C). However, DCPD tablets showed wax egress during the treatment. MCC tablets swelled and cracked during drug dissolution and resulted in quick release. DCPD and lactose tablets remained intact during dissolution and gave slower release than MCC tablets. DCPA tablets without heat treatment disintegrated very quickly and showed immediate release. In contrast, heat-treated DCPA tablets remained intact through the 24-hr dissolution test and only released about 80% PPA at 6 hr. In the investigation of wax level, DCPD was used as the diluent. The drug release rate decreased as the wax content increased from 15% to 81.25%. The dissolution data were best described by the Higuchi square-root-of-time model. Diluents showed various effects during heat treatment and drug dissolution. The integrity of the tablets was related to the drug release rate. Heat treatment retarded drug release if there was no wax egress.     

ICP-AES法测定原油中镍含量及不确定度评定

采用电感耦合等离子体发射光谱法(ICP-AES)定量分析原油中金属镍元素的含量,建立了测定镍含量不确定度的分析方法。从4个方面评定了不确定度分量的贡献,分别计算其相对标准不确定度,最终得到合成标准不确定度和扩展不确定度。通过分析计算表明,当原油中镍元素含量为19.64mg/kg时,其扩展不确定度为0.20mg/kg(k=2)。其中标准曲线拟合及标准物质自身引入的不确定度为主要影响因素,其次是溶液配制,而试样称量和测量重复性的贡献较小。     

水性清洗剂在空调用塑封电动机生产上的应用

目前,水性清洗剂在电机行业的应用尚未普及。为此,设计了3种清洗方案,对比了水性清洗剂与有机溶剂清洗剂应用于转子上的油污、金属屑、氧化物、灰尘等污物的清洗效果。通过残渣试验、光学显微镜评价不同清洗方案的清洗效果,通过电化学试验和中性盐雾试验分析清洗后转子的防锈效果。结果表明:3种方案的不可溶残留物含量分别为0.85,0.70,0.50 mg,电化学阻抗谱拟合的Rct分别为757.6,522.1,808.4Ω,说明方案3(先水性清洗剂清洗,再水基防锈剂清洗)的清洗效果和耐蚀性最好。工业应用试验表明:水性清洗剂结合水基防锈剂可以替代有机溶剂清洗剂在空调用塑封电动机转子清洗上应用,具有安全、可靠、低成本的特点,具有广泛的工业应用价值。