Elemental and mineral characterisation of Coastal Antarctic Aerosols in snow using PIXE and SEM-EDAX

The chemical constituents of snow from a 3 m pit sampled at a coastal Antarctic site were characterised by means of PIXE and SEM-EDAX. Oxygen isotope dating revealed that the pit spanned an 8-year period, from 1986 to 1994. Concentrations measured by PIXE ranged from less than 1 ng g⁻¹ of H₂O for Cu, and Zn to several tens of ng g⁻¹ for Si, S and Cl. The major elements found were Si, S, Al, and Na, which contributed more than 75% of the element loading. Snow layers with elevated Cl concentration were regularly found along the pit. The mineralogy of the insoluble particles determined by SEM-EDAX analyses showed that quartz, plagioclase and clays were the prevalent minerals. The proportion of each element in the insoluble phase was comparable with that previously found in similar studies.     

甘蔗茎中化学元素的微区分布

用扫描电镜-能谱仪研究了甘蔗茎皮层的外表面和横切面中Si等元素的含量及分布.结果表明,皮层外表面不同形态区域中Si等元素的含量不同,颗粒物是Si高度密集的部位,Si的含量高达58.23%;平坦处的Si含量较低,为44.42%;颗粒物块及其连接处中所含Si的原子数相同,但所含C、O元素的原子数则相反.横切面中,皮层中Si的密度高且分布呈外层低里层高的规律性;维管束及薄壁细胞中Si的含量较低且分布较均匀,皮下纤维层中Si的含量最低,具有明显不同于麦秆的特点.实验结果预示不同部位中硅化物的组成及元素化学状态的差异.     

Polygonatum odaratum extract as an eco-friendly inhibitor for aluminum corrosion in acidic medium

The corrosion of aluminum specimens in Polygonatum odaratum (P. odaratum) extract was studied using weight loss measurements, potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy (SEM), and electron dispersive X-ray spectroscopy (EDX) techniques. The inhibition efficiency of the aluminum specimens in the presence of inhibitor from P. odaratum plant extract at 303–333 ± 1 K was evaluated with the weight loss technique. The results indicate the inhibition efficiency of P. odaratum plant extract increased with increased concentration of the inhibitor and decreased temperature in an acidic medium. The corrosion inhibition properties of the P. odaratum plant extract for aluminum specimen corrosion in 1 M HCl were analyzed using polarization studies and electrochemical impedance studies, which clearly showed a mixed-type inhibitor. UV-visible spectroscopy, Fourier transform infrared (FT-IR), SEM, and EDX revealed the surface morphology in the presence and absence of inhibitor on the metal surface. The results indicated the feasibility of using the P. odaratum plant extract as a corrosion inhibitor in acid environments.     

麦草浆黑液燃烧法除硅研究

研究了硫酸铝对麦草浆浓黑液理化性能及除硅效果的影响.实验结果表明,铝盐有利于提高浓黑液膨胀率,在添加量为3%时达到了最大值64.19%;流变仪检测表明,在高温下铝盐添加量对浓黑液的黏度几乎没有影响,可在110℃输送浓黑液;黑液燃烧法结果表明,铝盐具有一定的除硅作用,硫酸铝的除硅效果最高可达53.02%;SEM-EDAX检测结果表明,铝离子能和硅形成不溶于水的沉淀物.上述结果表明:硫酸铝具有一定的除硅效果,当其添加量为3%时除硅效果最好.     

Hydrotreating of Maya Crude Oil: I. Effect of Support Composition and Its Pore-diameter on Asphaltene Conversion

A systematic study for a concept governing support effect in heavy oil hydrotreating (HDT) catalysts is performed. Different Al₂O₃ and its mixed oxides supports were prepared and CoMo supported catalysts were tested for Maya heavy crude oil hydrotreating. Fresh and spent catalysts are characterized with N₂ adsorption-desorption, element analysis, and scanning electron microscopy-energy dispersion analysis by x-ray (SEM-EDAX), which confirms that coke and metals deposition on the surface of catalyst is most probably near the pore mouth. It is also demonstrated from these results that asphaltene conversion depends on the pore diameter of the catalyst, while other hydrotreating conversions (hydrodesulfurization (HDS), hydrodenitogenation (HDN), and in some extent hydrodemetallization (HDM)) are more likely affected by the nature of active metal distribution. The evaluation of alumina mixed oxide (TiO₂, ZrO₂, B₂O₃, and MgO) supported catalysts indicates that supports with basic nature have better stability than the acid ones.     

扫描电镜能谱辨识纸质材料燃烧灰烬的研究

利用扫描电镜能谱仪,分析了常见纸质材料——静电复印纸、纸巾纸、报纸和瓦楞纸板等燃烧后灰烬颗粒的形貌特征、成分及组成比例,分析了水分、温度对灰烬颗粒形貌的影响。结果表明,以上4种纸质材料的灰烬颗粒形貌明显不同。静电复印纸灰烬颗粒外形单一,钙元素含量远高于其他元素;纸巾纸灰烬中纤维体边沿上有呈圆点状或细条状元机物;报纸灰烬中纤维状物质形多样;瓦楞纸板灰烬中含有较多的奇特形状颗粒,且氮元素含量高。     

麦草原料矿质元素的SEM-EDAX研究

用扫描电子显微镜-能谱仪(SEM—EDAX)研究麦草原料的矿质元素含量及分布。结果表明，麦秆节间皮层外表面平滑，呈纵向排列、平行相间的条纹；元素的组成简单，仅含C、O、Si、K等元素，Si含量高达56．285％。皮层外表面元素的电子地图表明，Si密度分布也呈现高低相间、纵向排列的平行纹理，K、Cl则均匀分布。麦秆外表面Si含量明显高于内表面；节部、穗部的Si含量高；纤维细胞的Si含量最低，约为皮层Si含量的1／30-1／140。Si是麦茎皮层生物结构中起关键作用的元素。不同产地的原料及同一原料不同部位中矿质元素的种类及含量差别甚大。研究认为，加强备料，开发新的预处理工艺及设备，有效除去麦草的节、穗及茎秆的皮层，对实现麦草浆的高效清洁生产具有重要意义。     

Corrosion Protection Behavior of Poly(N-(p-bromophenyl)-2-methacrylamide-co-ethyl methacrylate) Coatings on Low Nickel Stainless Steel

The copolymer poly(N-(pbromophenyl)-2-methacrylamide-co-ethyl methacrylate) has been synthesized by free radical solution polymerization. Thermal stability of the synthesized copolymer was analyzed using thermogravimetric analysis and differential thermal analysis techniques. The corrosion performances of low nickel stainless steel specimens coated with different mole ratios of poly(PBPMA-co-EMA) were investigated with 1 M H₂SO₄ using potentiodynamic polarization, electrochemical impedance spectroscopic studies and chronoamperometric studies. Moreover, all the mole ratios of this copolymer showed good protection against corrosion. Surface and morphological investigation of the product have been studied with the help of scanning electron microscopic, atomic force microscopic, and energy dispersive X-ray analysis techniques, they were used to characterize the adherence and uniformity of the coatings, electrochemical corrosion test and surface analysis results have proved that poly(PBPMA-co-EMA) coatings served as a stable host matrix on low nickel stainless steel as environmentally more favored and best anticorrosive coating.     

麦秆皮层矿质元素的微区分布

用扫描电子显微镜-能谱仪(SEM—EDAX)研究麦秆节间皮层矿质元素的微区分布及Si等元素的电子地图。结果表明，节间外表面有2种形态，Si含量高达30％～60％。多数外表面呈高低相间的纵向平行条纹；这种皮层的外表面及皮层中Si的分布也呈高低相间的纵向平行条纹。少量外表面较粗糙，具粒状物且气孔器分布较多；粒状物是Si高度密集的部位；气孔器周围的Si密度明显提高，Si高度密集的气孔器壁深入到皮下纤维层中。麦秆皮层主要由C、O、Si、K等元素组成，并含有少量Cl、Ca、Al等元素。节间皮层中Si的含量呈规律性分布。与皮层相邻的纤维细胞壁中含Si量较高。Si是皮层生物结构中起决定作用的元素。麦秆不同部位的皮层中，C、O、Si等元素的含量及分布特点不同，预示着这些元素存在的化学状态的差异。     

Fabrication, characterization and bioactivity evaluation of calcium pyrophosphate/polymeric biocomposites

The design of the biocomposites offers the opportunity to create grafting materials with excellent bioactivity, resorbability and improved mechanical properties. In this study, we are concerned with the preparation of calcium pyrophosphate (CPP) and its composites with polymeric matrix to enhance these properties. The fabricated biocomposites were characterized by X-ray diffraction (XRD), Fourier transformer infrared spectra (FT-IR), thermogravimetric (TGA) analyses and scanning electron microscope with X-ray elemental analysis (SEM-EDAX). The characterization results confirmed homogeneity, interaction and integration between the CPP filler and polymeric matrix. The mechanical properties of biocomposites had enhanced values compared to the original copolymer matrices and were comparable to those of cancellous bone. In vitro test results via calcium and phosphorous ions measurements, showed that the biocomposites had enhanced ability to accelerate the mineralization of calcium phosphate layer on their surfaces. FT-IR and SEM-EDAX post-immersion confirmed that the CPP/polymeric composites containing chitosan or chitosan–gelatin matrix had ability to induce a bone-like apatite layer onto their surfaces. Finally, a novel CPP/polymeric biocomposites have good bioactivity and suitable mechanical properties; therefore, they could be used in bone grafting and tissue engineering applications in future.