火花放电原子发射光谱类型标准化校正方式的探讨

在国内,火花放电原子发射光谱分析广泛使用类型标准化进行方法校正。在国外,标准和文献中鲜见使用此方法的相关论述。类型标准化主要采用平移校正和转动校正两种方式,哪种方式更加合理也鲜见报道。国外设备类型标准化的默认设置优先采用转动校正方式,相关国内标准对最优校正方式的规定尚不明确,此默认设置的合理性有待探讨。实验选用低合金钢20CrNi2Mo、R407标准样品和不锈钢317L、0Cr18Ni9标准样品,引用国内相关标准,以正确度临界差为评判依据,模拟类型标准化样品和待测样品“十分接近”和“接近”两种情况下平移校正和转动校正的数据正确度。经数据统计分析,平移校正分析结果均满足要求,转动校正结果在“接近”情况下部分元素不满足要求。结合相关国家标准中元素含量范围和精密度数据进行分析,通过计算允许最大偏倚量并制作曲线图方式展开分析,得出如下结论:在满足文中类型标准化控制要点前提下,分析设置更适合于采用平移校正方式。     

13种食用植物油中矿物质元素含量的研究

建立了湿法消解-原子吸收光谱法测定食用植物油中6种矿物质元素(Mg、K、Ca、Fe、Cu、Zn)的分析方法。结果表明:优化的湿法消解条件为以硝酸-过氧化氢作为消解溶液,硝酸用量20.00 m L,加热功率500 W;6种目标物在各自的线性范围内线性关系良好(r≥0.998),检出限为0.32~21.16 mg/kg,3种食用植物油加标回收率为82.9%~115.0%,相对标准偏差为1.1%~8.8%。通过该分析方法对13种食用植物油中6种矿物质元素含量进行对比研究,结果发现火麻油中矿物质元素含量较丰富,营养价值较高。     

检测仪器及消解方式对罗布麻微量元素检测效果的影响

目的 探索罗布麻微量元素适宜的检测条件。方法 以新疆产罗布麻和白麻叶及其制品罗布麻茶为实验材料, 比较了电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)和电感耦合等离子体原子发射光谱法(inductively coupled plasma atomic emission spectrometry, ICP-AES)2种仪器对其Li、B、Cr、Fe、Mn、Cu、Zn、Se和Sr 9种微量元素的检测效果, 同时对比了3种不同的湿法消解方式对检测结果的影响。结果 采用不同酸解液的3种湿法消解方法, 硝酸/过氧化氢消解液处理条件较温和, 元素损失量较少, 检测结果稍高于浓硝酸/高氯酸消解液处理的结果, 但所耗消解时间更长。对于易挥发元素Se, 选用酸性和氧化性较弱的硝酸/过氧化氢消解液更适宜。在本试验条件下, 罗布麻体内的Li和Cr 2种微量元素不宜采用ICP-AES仪器检测, 可选用ICP-MS, 而对于难电离元素Se则正好相反。结论 检测罗布麻微量元素含量时, 应根据待检测元素类型特征, 选择适宜的检测仪器。     

Single nanowire assembled by liquid dielectrophoresis for on-chip technologies

ABSTRACT

Study on dynamic tensile properties and atomic chain fabrication of single nanowire, for understanding its dynamic tensile properties and unique physical properties of atomic chain to fabricate atom scale devices, is one of frontier research issues in nano-scale science. However, how to assemble single nanowire on a tensible micro-structure becomes one of the most difficult problems, which severely restricts the development of this research field. In this paper, after the ultrahigh tensible microelectrode chip is fabricated by micro-electromechanical systems technology, hexamethyldisilazane is utilized to improve hydrophobicity of the chip, and then a micro-droplet dielectrophoresis experimental platform and technology is developed to assemble single nanowire on the sensible microelectrode. Experimental results show that accurate and efficient assembly of single Cu nanowire is realized, which contributes greatly to the further research of dynamic tensile properties and atomic chain fabrication. And for guiding the assembly experiments, finite element technology is also utilized to analyze the local micro electro-field around the microelctrodes during dieletrophoresis experiments.     

原子层沉积技术对纤维素膜功能化的影响

为扩大纤维素膜的使用范围,使其可应用于医用、建筑等领域,利用纳米氧化锌具有紫外线屏蔽、抗菌等特性,采用原子层沉积(ALD)技术在纤维素膜表面沉积纳米氧化锌,制备具有紫外线阻隔以及抗菌功能的纤维素膜,并探讨不同ALD温度和循环次数对纤维素膜性能的影响。借助紫外分光光度计、扫描电子显微镜、X射线衍射仪、热重分析仪等对纤维素膜的结构和性能进行分析。结果表明:随着ALD温度和循环次数的增加,纤维素膜的紫外线透过率由74.50%下降至1.46%; ALD功能化纤维素膜对金黄色葡萄球菌的抑菌率高达99.9%;经改性的纤维素膜表面附着了六方晶系纤锌矿结构的纳米氧化锌层,残碳率由16.61%增加至31.20%。     

Thin‐film nanostructure and polymer architecture in semicrystalline syndiotactic poly(p‐methylstyrene)–(cis‐1,4‐polybutadiene) multiblock copolymers

The thin‐film morphology of stereoregular syndiotactic poly(p‐methylstyrene)–(cis‐1,4‐polybutadiene) (sP(pMS–B)) multiblock copolymers has been investigated using tapping mode atomic force microscopy with variation of the polymer composition and monomer block lengths. The morphology of the thin films ranges from isolated circular domains of sP(pMS) embedded into a matrix of polybutadiene (PB) to isolated domains of PB embedded into a matrix of sP(pMS), passing through bicontinuous (jagged) lamellae when the pMS concentration is in the range 20–67 mol%. Multiple folding of the polymer segments, i.e. where reciprocal inclusions of polymer segments to each other phase are able to generate greater domain, has been postulated and validated by considerations on the polymer architecture and the thermal and crystalline behaviour. © 2019 Society of Chemical Industry     

Finite element simulation based‐on atomic force microscopy and nanoindentation for spruce wood microstructure analysis

Spruce wood (picea abis) has been widely used as structural element, from buildings to musical instruments, due to its outstanding mechanical performances. The main stem transverse section exhibits growth rings formed by periodic fringes patterns, which are constituted by lamellae‐tracheid arrangements. In order to improve the understanding of each wood microstructure role, the morphology and crystallinity of earlywood and latewood fibers were examined mainly using scanning electron microscopy, atomic force microscopy, and X‐ray difracction. Moreover, measurements of effective elastic modulus and hardness were obtained by nanoindentation tests using a Berkovich indenter in order to confirmed increase in compactness of the wood microstructures. The results indicate that variations in mechanical properties values can be associated with well defined microstructural performances for each characteristic fiber type, where those that belong to latewood fiber showed the most improved behaviors. A finite element simulation of a lamellar‐tracheids arrangement was carried out in order to clarify its stiffness and elastic deformation capabilities, as relevant factors contributing to the successful adaptation of picea abis colonies to harsh conditions habitats as well as for its construction applications of string instruments.     

不同消解方法对土壤中铜锌测定的影响

采用微波消解法和石墨消解法对土壤样品进行预处理,用火焰原子吸收分光光度法测定土壤中铜和锌的含量。对3个土壤标准物质(GSS-17、GSS-30、GSS-34)的精密度和准确度进行了分析,结果表明:微波消解法和石墨消解法的检出限、精密度和准确度均能满足土壤检测的要求,石墨消解法相对于微波消解法更加便捷,具有很好的精密度和准确度。     

Temperature influence on the development of interdiffusion phenomena in MCrAlY-coated nickel-based superalloys

In this work, the interdiffusion between a MCrAlY-bond coat and two different nickel-based superalloys is evaluated at three temperatures, 950 °C, 980 °C, and 1,050 °C. Of primary interest is the evolution of Kirkendall-porosity, the β-depleted zone in the bond coat and the β’- depleted zone in the superalloy. The three phenomena arise near the interface between bond coat and superalloy as a result of interdiffusion between both materials and are detrimental to the coating-substrate system. The evolution of the interdiffusion phenomena is highly dependent on the alloy composition of the materials as well as the annealing temperature. It has been found that not only the temperature dependency of the diffusion coefficient but also the temperature dependent element activities are an important factor when evaluating the interdiffusion phenomena. It has further been shown that at lower temperatures the amount of Kirkendall-porosity per volume fraction is higher than at higher temperatures, even though the overall amount of porosity is lower. Different equilibrium concentrations of main alloying elements and a correspondingly lower over-saturation of vacancies have been identified as the main explanation.     

火焰原子吸收光谱法和电感耦合等离子体发射光谱法测定黄酒中氧化钙含量的方法对比研究

目的比较火焰原子吸收光谱法(flame atomic absorption spectrometry,FAAS)和电感耦合等离子体发射光谱法(inductively coupled plasma optical emission spectrometry,ICP-OES)测定黄酒中的氧化钙含量。方法将黄酒样品、加标试样样品、质控样品通过微波消解仪消解,定容后分别用火焰原子吸收分光光度计,电感耦合等离子体发射光谱仪测定样品中钙的含量,并对2种方法的线性范围、方法检出限、精密度和回收率进行考察。结果FAAS法的方法检出限和精密度分别为0.10μg/m L和0.0223 g/L,ICP-OES法的方法检出限和精密度分别为0.015μg/m和0.00873 g/L,ICP-OES法有更低的检出限和更高的精密度,2者检测样品结果相对标准偏差(RSD)在3%以内,回收率在96.4%～102.6%之间,相关系数r为0.9995～0.9999,这2种方法中标准参考物质菠菜(GSB-6)中的钙含量的测定值在标准参考范围内。结论FAAS法测定黄酒中的氧化钙,前处理操作复杂,并且酸度对测定结果有较大影响,同时该法的检出限较高和精密度较低,而ICP-OES法线性关系好,检出限低,稳定性好,回收率高,测定结果准确,因此该法更适合黄酒中氧化钙的测定。