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.     

能量色散X射线荧光光谱法测定PVC塑料中铅、铬、汞、镉、溴含量的不确定度评定

对能量色散X射线荧光光谱法测定PVC塑料中铅、铬、汞、镉、溴元素含量的不确定度进行了评定。分析了测量结果的不确定度由测量重复性、回归工作曲线、标准物质、仪器综合稳定性等因素引入的不确定度分量组成。在对各个不确定度分量进行量化的基础上,通过计算得到测量结果的合成不确定度和扩展不确定度。     

原子吸收光谱法测定鱼粉中铬含量测量结果的不确定度分析

依据GB/T13088-2006《饲料中铬的测定》标准测量鱼粉中的铬含量,对整个测量过程中不确定度的来源进行了分析,并对不确定度各个分量进行了评定、合成,最后得出合成不确定度和有效自由度。     

氢化物发生-原子荧光光谱法同时测定煤炭中砷、汞含量的不确定度评估

本文对煤炭中砷、汞含量测定的不确定度进行了评估。用氢化物发生-原子荧光光谱法同时测定了煤炭中的砷、汞含量,通过对影响样品测量结果的不确定度分量的分析和量化,计算出被测量(砷、汞含量)的标准不确定度和扩展不确定度,从而给出各分量对总测量不确定度的相对贡献,并对测量结果进行了表述。     

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。     

可视滴定法测定不锈钢中铬含量的不确定度评定

采用可视滴定法测定不锈钢中铬的含量,笔者通过分析研究,确定了测量的不确定度的主要来源是测量的重复性、基准物质、标定所消耗硫酸亚铁铵溶液的体积,量具体积以及样品的质量,通过数学公式分量计算不确定度并将其合成,测量结果的合成标准不确定度为0.060%,扩展不确定度为0.12%,即k=2时,此区间包含了测定结果可能值得95%。     

水基胶中乙酸乙烯酯测定的不确定度评定

为了评价顶空-气相色谱法测定水基胶中乙酸乙烯酯结果的准确性,建立相关数学模型,计算影响测量的各个不确定度分量,建立不确定度的评定方法。结果表明:1由标准工作溶液制备、标准工作曲线拟合、回收率实验等引入的不确定度分量所占权重较大,而试样制备、重复性所引入的不确定度占权重较小;2当水基胶样品中残留量为54.08mg/kg时,其合成标准不确定度为1.36mg/kg,扩展不确定度为2.72mg/kg(p=95%,k=2)。可以通过改变标准溶液浓度范围,使其与样品浓度值相匹配,以减小曲线拟合和回收率引入的不确定度,提高测量结果的可靠性和准确性。     

饲料中粗灰分的测量结果不确定度评定

本文介绍用重量法测定饲料样品的粗灰分含量。通过对影响样品测试结果的不确定度分量的分析和量化 ,求出被测量 (粗灰分含量 )的标准不确定度和扩展不确定度U =2uc(A) =0 0 7% ,给出各分量对测量结果不确定度的相对贡献 ,对测量结果进行了表述。     

动态法测定石英杨氏模量的不确定度评定

按照分析测试中测量不确定度评定的方法,对利用弹性模量测试仪采用动态法测定石英杨氏模量时测量重复性、仪器准确度、样品质量测量、样品尺寸测量等引入的不确定度分量进行了评定,计算出石英杨氏模量的扩展不确定度。     

闪光法测定氧化铝陶瓷导热系数的不确定度评定

按照分析测试中测量不确定度及评定的方法程序,对利用闪光导热仪测定氧化铝陶瓷导热系数时重复测量、仪器读数、样品厚度测量、样品密度测量等引入的不确定度分量进行了评定,计算出氧化铝陶瓷导热系数的扩展不确定度。     

陶瓷微珠包覆铜的制备及激光光谱特性研究

采用化学镀方法制备了陶瓷微珠包覆铜复合材料,通过SEM、XRD和EDS研究了还原剂浓度对陶瓷微珠包覆铜的形貌及包覆情况的影响,得出了最佳包覆条件。采用近红外分光光度计、CO2激光器和激光能量计检测了不同硫酸铜浓度下陶瓷微珠包覆铜在1.06μm附近的光谱反射率和10.6μm的激光反射率,随硫酸铜浓度的增大,1.06μm附近的光谱反射率和10.6μm的激光反射率下降。     

氧桥连双核茂钛催化剂催化苯乙烯的聚合

以氧桥连双核茂钛配合物（CpTiCl2）2O和甲基铝氧烷（MAO）组成的催化体系实现苯乙烯聚合,详细考察了聚合温度,Al/Ti物质的量比,聚合时间,主催化剂浓度[Ti]等条件对聚合反应的影响。研究发现,升高温度对提高活性有利,但是会导致聚合物等规度降低。聚合产物经差示扫描量热（DSC）,红外光谱（FT-IR）和凝胶渗透...     

CuCl+注入α-Al2O3晶体退火后表面亚微米颗粒的形成情况研究

CuC l+离子注入不同晶向的α-A l2O3晶体中,对在还原气氛下退火后的试样进行SEM表面观察。结果发现,不同注入条件和不同温度退火的不同晶向α-A l2O3晶体表面均形成弥散的亚微米颗粒。说明CuC l+离子注入α-A l2O3晶体产生的缺陷损伤在退火过程中,单个分散的带电色心缺陷与CuC l+离子形成的缺陷缔合体在恢复过程中发生了CuC l原子的偏聚,随着退火时间的增加,偏聚程度提高而形成颗粒,并逐渐长大形成亚微米颗粒。颗粒的大小和分布随注入条件以及退火温度不同而不同。     

X-ray computed microtomography to study autogenous healing of cementitious materials promoted by superabsorbent polymers

Autogenous healing of cracks may offer a solution for brittle cementitious materials. In this study, the healing building blocks are available through the well-designed ultra-ductile microfibre-reinforced mixture with a low water-to-binder ratio and water is available through the inclusion of superabsorbent polymers. As visual inspection demonstrates that the crack is completely closed at the surface, one may ask whether this healing also is present in the interior of the crack. X-ray computed microtomography was therefore used to study the extent of autogenous healing in cracked cylindrical specimens. It was found that the extent of autogenous healing in a cementitious material depends on the crack depth. Only near the crack mouth (0 till 800–1000 μm) the crack is closed by calcium carbonate formation in case of wet/dry cycles. In combination with superabsorbent polymers, the extent of healing was more substantial. For mixtures containing superabsorbent polymers there was even partial healing in the interior of the crack when stored at a relative humidity of 60% or more than 90%. Energy-dispersive spectroscopy combined with microscopic analysis showed that the healing products were mainly calcium carbonate. The smart cementitious material with superabsorbent polymers is thus an excellent material to use in future building applications as the healing capacity is improved.     

Multiscale characterization of chemical–mechanical interactions between polymer fibers and cementitious matrix

Together with a series of mechanical tests, the interactions and potential bonding between polymeric fibers and cementitious materials were studied using scanning transmission X-ray microscopy (STXM) and microtomography (μCT). Experimental results showed that these techniques have great potential to characterize the polymer fiber-hydrated cement-paste matrix interface, as well as differentiating the chemistry of the two components of a bi-polymer (hybrid) fiber – the polypropylene core and the ethylene acrylic acid copolymer sheath. Similarly, chemical interactions between the hybrid fiber and the cement hydration products were observed, indicating the chemical bonding between the sheath and the hardened cement paste matrix. Microtomography allowed visualization of the performance of the samples, and the distribution and orientation of the two types of fiber in mortar. Beam flexure tests confirmed improved tensile strength of mixes containing hybrid fibers, and expansion bar tests showed similar reductions in expansion for the polypropylene and hybrid fiber mortar bars.     

2 μm emission properties and hydroxy groups quenching of Tm3+ in germanate-tellurite glass

Tm³⁺ activated germanate-tellurite glasses with good thermal stability and anti-crystallization ability were prepared. Efficient 2 μm fluorescence was observed in the optimal concentration Tm³⁺ doped glass and the corresponding radiative properties were investigated. For Tm³⁺: ³F₄ → ³H₆ transition, high spontaneous radiative transition probability (260.75 s⁻¹) and large emission cross section (7.66 × 10⁻²¹ cm²) were obtained from the prepared glass. According to Dexter's and Forster's theory, energy transfer microscopic parameters were computed to elucidate the observed 2 μm emissions in detail. Besides, the effect of hydroxy groups quenching was also quantificationally investigated based on simplified rate equations. Results demonstrate that the optimal concentration Tm³⁺ doped germanate-tellurite glass possessing excellent spectroscopic properties might be an attractive candidate for 2 μm laser or amplifier.     

High resolution X-ray tomography – three-dimensional characterisation of cell–scaffold constructs for cartilage tissue engineering

Abstract

Synchrotron radiation based microcomputed tomography (SR-μCT) has become a valuable tool for the structural analysis of different types of biomaterials. This methodology allows the non-destructive investigation of specimens in their three-dimensional context. In the present paper, articular cartilage is taken as an exemplary tissue to demonstrate the suitability of the SR-μCT method for the investigation of biomaterials for different tissue engineering approaches. Thus, a biodegradable scaffold for cartilage tissue engineering in different modifications was analysed. Using enhanced phase contrast imaging, it was possible to demonstrate single cells without further metal staining. The three-dimensional data acquired for each investigated sample allowed qualitative and quantitative analyses without irreversibly damaging the samples. The use of the phase contrast mode enables the analysis of single cells within a scaffold material even under mechanical stimulation. This opens up innovative perspectives for the future study of the behaviour of cells in their three-dimensional environment and the non-destructive study of morphogenesis in cell–scaffold constructs.     

Light emission at 2 μm from Ho-Tm-Yb doped silicate glasses

The 2.0 μm emission properties and thermal stability of Yb-Tm-Ho triply-doped silicate glass are investigated. The characteristic temperatures, absorption spectrum and fluorescence spectra of the glasses are measured. Intensive emission near 2.0 μm is observed upon excitation at 980 nm and the corresponding mechanisms are discussed. Based on the measured absorption spectra, the absorption and emission cross sections, the Judd-Ofelt parameters and radiative properties are calculated and discussed. The predicted spontaneous transition probability for Ho³⁺:⁵I₇ → ⁵I₈ transition in silicate glass is 58.05 s⁻¹. The results indicate that the energy transfer in Yb³⁺ → Tm³⁺, Yb³⁺ → Ho³⁺, Tm³⁺ → Ho³⁺ is efficient and the Yb-Tm-Ho triply-doped silicate glass is a promising 2.0 μm laser glass material.     

2μm波段激光晶体研究进展

综述了以Ho、Tm、Er为激活离子、以YAG、YAP及YLF为基质的2μm波段激光晶体的特点及应用背景,详细讨论了几种重要2μm波段激光晶体的能级结构、光谱特性及器件研究进展,指出了适合LD泵浦是今后2μm波段激光晶体的发展方向.