重量法测定工业磷酸中磷酸含量的测量不确定度评定

按照测量不确定度评定的通用规则,建立了数学模型,对重量法测定工业磷酸中磷酸含量的测量不确定度进行了评定,分析了方法中的不确定度分量及其来源,计算了各分量的不确定度,最后计算出了检测结果的合成标准不确定度和扩展不确定度。检测结果和不确定度评定结果为（85．200．26）％,k=2。洗涤沉淀造成沉淀损失引起的测量不确定度分量为最大。     

微量法测定石油产品中残炭含量的不确定度评价

按照测量不确定度评定的通用规则,建立了数学模型,对微量法测定石油产品中残炭含量的测量不确定度进行了评定,分析了方法中的不确定度分量及其来源,计算了各分量的不确定度,最后计算出了检测结果的合成标准不确定度和扩展不确定度。检测结果和不确定度评定结果为（0．35±0．02）％,k=2。残炭质量称量引起的测量不确定度分量为最大。     

骨质瓷中磷酸三钙含量检测的不确定度评定

按照JJF1059-1999《测量不确定度评定与表示》建立了数学模型,对骨质瓷中磷酸三钙含量的测量不确定度进行了评定;分析不确定度分量及其来源,计算了各分量的不确定度,最后计算出检测结果的合成标准不确定度和扩展不确定度。检测结果和不确定度评定结果为（38．26±0．20）％、k=2,沉淀洗涤造成沉淀损失引起的测量不确定度分量最大。     

原子吸收法测定贵金属催化剂中钯含量不确定度的评定

依据标准SH/T0684-1999 《分子筛和氧化铝基催化剂中钯含量测定法(原子吸收光谱法)》对贵金属催化剂中钯含量的测定进行了不确定度的评定。在研究中,通过建立数学模型,分析检测结果不确定度的主要来源,并对不确定度的各个分量进行评定,最后计算出了测量结果的合成标准不确定度为0. 0171%,扩展不确定度为0. 034%(取扩展因子k=2),检测贵金属催化剂中的钯含量结果为0. 367%±0. 034%(k=2)。     

电感耦合等离子体质谱法测定水中铅的不确定度

评定电感耦合等离子体质谱仪测定水中铅的不确定度。依据测量不确定度评定与表示的理论,建立了检出限的测量结果不确定度评定的数学模型,分析了各相对标准不确定度分量,计算了合成标准不确定度和扩展不确定度。检出限测量结果不确定度报告为DL=0. 0061 ng,U=0. 0020 ng(k=2)。由标准不确定度分量值可以得出,电感耦合等离子体质谱仪检测水中铅检出限结果不确定度主要是标准曲线斜率引入的不确定度。     

GCMS测定电子电气产品中BDE-209含量的不确定度评定

分析了用气相色谱-质谱联用法(GCMS)测定电子电气产品中十溴二苯醚(BDE-209)含量的检测过程,运用测量不确定度评定的理论,对测定的结果的不确定度进行了评定,分析了不确定度的来源,对各分量进行了计算,合成不确定度。最终结果的不确定度主要由工作曲线、样品前处理以及测量重复性等不确定度引起。本文建立的不确定度评定方法可用于GCMS法测定电子电气产品中其他的多溴联苯和多溴二苯醚含量的不确定度评定。     

气相色谱法测量化妆品中甲醇的不确定度评定

目的:建立气相色谱(GC)法测定化妆品中甲醇的不确定度评定方法。方法:依据国家计量技术规范JJF1059.1-2012《测量不确定度评定与表示》进行不确定度评定,结果:研究分析了《化妆品安全技术规范》(2015版)第四章2.22中甲醇含量的检测过程,得到测量不确定度评定的包括甲醇标准溶液不确定度、化妆品称量的不确定度、检测过程的重复性不确定度在内的各分量以及合成标准不确定度,结论:指出化妆品中甲醇含量测量不确定度的主要来源,为此可以更客观科学地评价该测量结果。     

离子色谱仪最小检测浓度不确定度评定

介绍离子色谱仪的电导检测器(阴离子和阳离子)、电化学测器和紫外可见检测器最小检测浓度的测量不确定度评定方法，建立了测量过程中各不确定度分量的测量模型，对不确定度的来源进行了分析，并给出了实际评定不确定度的过程。     

重量法测定白云石中硅含量的不确定度评定

根据高氯酸脱水重量法测定白云石中硅检验方法规定的测量程序,建立了测量过程的数学模型,对检测过程中各分量产生不确定度的各种因素进行了评估,对一个白云石试样中硅量的测量结果进行了不确定度评定,比较了他们不确定度的大小,当二氧化硅平均含量为7.74%时,求得合成标准不确定度为0.004%,扩展不确定度为0.01%(k=2)。     

石膏中氧化钾检测不确定度评定

测量不确定度是"表征合理地赋予被测量之值的分散性,与测量结果相联系的参数"。测量不确定度是一个新的术语,它从根本上改变了将测量误差分为随机误差和系统误差的传统分类方法,它在可修正的系统误差修正以后,将余下的全部误差划分为可以用统计方法计算的(A类分量)和其他方法估算的出类分量(B类分量)两类误差。本文按照JJF1059.1-2012《测量不确定度评定与表示》上的方法以石膏中氧化钾检测为实例,对其进行不确定度的评定。     

Silicon Carbide Monofilament-Reinforced Silicon Nitride or Silicon Carbide Matrix Composites

SiC-monofilament-reinforced SiC or Si₃N₄ matrix composites were fabricated by hot-pressing, and their mechanical properties and effects of filaments and filament coating layers were studied. Relationships between frictional stress of filament/matrix interface and fracture toughness of SiC monofilament/Si₃N₄ matrix composites were also investigated. As a result, it was confirmed experimentally that in the case of composites fractured with filament pullout, the fracture toughness increased as the frictional stress increased. On the other hand, when frictional stress was too large (>about 80 MPa) for the filament to be pulled out, fracture toughnesses of the composites were almost the same and not so much improved over that of Si₃N₄ monolithic ceramics. The filament coating layers were found to have a significant effect on the frictional stress of the SiC monofilament/Si₃N₄ matrix interface and consequently the fracture toughness of the composites. Also the crack propagation behavior in the SiC monofilament/Si₃N₄ matrix composites was observed during flexural loading and cyclic loading tests by an in situ observation apparatus consisting of an SEM and a bending machine. The filament effect which obstructed crack propagation was clearly observed. Fatigue crack growth was not detected after 300 cyclic load applications.     

Silicon Carbide/Silicon and Silicon Carbide/Silicon Carbide Composites Produced by Chemical Vapor Infiltration

Composites of SiC/Si and SiC/SiC were prepared from single yarns of SiC. The use of carbon coatings on SiC yarn prevented the degradation normally observed when chemically vapor deposited Si is applied to SiC yarn. The strength, however, was not retained when the composite was heated at elevated temperatures in air. In contrast, the strength of a SiC/C/SiC composite was not reduced after this composite was heated at elevated temperatures, even when the fiber ends were exposed.     

以二氧化硅为硅源制备纯硅的方法

介绍了纯硅材料的类型及其主要用途,叙述了国内外以二氧化硅为硅源,热还原法(包括金属、非金属和耦合热还原法)、熔盐电解法(包括氟化物、氯化物和耦合熔盐电解法)等制备纯硅的方法,评叙了各种方法的优缺点。指出氯化钙熔盐电解法工艺简单、产品纯度高、能耗小、成本低、经济效益好、环境友好、市场潜力与前景较好。     

Silicon Carbide Platelet/Silicon Carbide Composites

α-silicon carbide platelet/β-silicon carbide composites have been produced in which the individual platelets were coated with an aluminum oxide layer. Hot-pressed composites showed a fracture toughness as high as 7.2 MPa·m^1/2. The experiments indicated that the significant increase in fracture toughness is mainly the result of crack deflection and accompanying platelet pullout. The coating on the platelets also served to prevent the platelets from acting as nucleation sites for the α- to β-phase transformation, so that the advantageous microstructure remains preserved during high-temperature processing.     

氮化钒铁中硅含量的硅钼蓝分光光度法研究

采用硅钼蓝分光光度法测定氮化钒铁中的硅含量,研究了氮化钒铁溶样方法,通过溶样效果,选择确定溶样酸。结果表明,该方法准确度高、重复性好,操作简便,可广泛运用于氮化钒铁中硅的检测。     

Silicon/Silicon Carbide Composites Fabricated by Infiltration of a Silicon Melt into Charcoal

Dense Si/SiC composites were fabricated via a conventional reaction-bonding process, using oak charcoal that exhibited a honeycomb structure. The silicon melt was infiltrated into the porous oak charcoal (density of ~0.6 g/cm³) while the sample was heated to 1700°C under vacuum (10^-3 torr (~0.133 Pa)), which resulted in in situ silicon-fiber/SiC composites. The reaction product had an average density of 2.8 g/cm³ and showed three-point flexural strengths of 330 MPa at room temperature and 280 MPa at 1300°C. Good oxidation resistance also was observed at temperatures up to 1300°C in flowing air. This process provided excellent shape-making capability, because the charcoal that was used as a preform was readily machinable.     

Nonaqueous Processing of Silicon for Reaction-Bonded Silicon Nitride

Ethanolic silicon suspensions, with and without a polyethoxylated amine of low molecular weight, were studied by rheological, adsorption, electrophoretic, and sedimentation methods. Pellets were pressure-cast and nitrided to form reaction-bonded silicon nitride. Density and binding strength in the green state relate well to rheological behavior and other collodial aspects of the suspensions used, particularly the additive's role and distribution. Density and degree of nitridation in the final state are not importantly affected by the additive's use. Its greatest benefit is to modify the binding strength in the green state. The mode by which this small molecule affects the processing of silicon consists of adsorption, combined with an increased electrostatic interparticle repulsion which increases the suspension viscosity and that of undried pellets. Although the improved binding strength is accompanied by decreased green and nitrided densities, high degrees of conversion to silicon nitride are still achieved.     

Oxidation of Chemically-Vapor-Deposited Silicon Nitride and Slnglem-Crystal Silicon

Oxidation of {111} single-crystal silicon and dense, chemically-vapor-deposited silicon nitride was done in clean silica tubes at temperatures of 1000° to woo°C. The oxidation rates of silicon nitride under various atmospheres (dry O₂, wet O₂, wet inert gas, and steam) were several orders of magnitude slower than those of silicon under the identical conditions. The activation energy for the oxidation of silicon nitride decreased from 330 to 259 kJ/mol in going from dry O₂ to steam while that for Si decreased from 120 to 94 kJ/mol. The parabolic rate constant for Si increased linearly as the water vapor pressure increased. However, the parabolic rate constant for silicon nitride showed nonlinear dependency on the water vapor pressure in the presence of oxygen. The oxidation kinetics of silicon nitride is explained by the formation of nitrogen compounds (NO and NH₃) at the reaction interface and the counterpermeation of these reaction products.     

Silicon Carbide Powder Synthesis from Silicon Monoxide and Methane

SiC was synthesized via the gas-phase reaction between SiO and CH₄ at 1500° and 1560°C in a tubular flow reactor. SiO vapor was generated from equimolar powder mixtures of Si and SiO₂ in the reactor while CH₄ was externally supplied. Products of different morphologies were collected at different longitudinal locations: whiskers, crystal aggregates, scale, and powder. The total yield of SiC, based on the amount of SiO generated, reached as high as 99%, of which 25–46% by mass was fine powder with sizes ranging from 60 to 300 nm.     

ICP—AES法测定高硅钢中的硅

研究了用ICP-AES法快速测定高硅钢中的硅,确定了最佳测定条件.在此条件下测定,获得满意结果.实验结果表明,该方法简便、快速、灵敏,检出限为0.000 9 μg/mL;RSD＜0.5 %;回收率为99 %～101 %,结果令人满意.