非化学计量羟基磷灰石骨水泥的制备及性能研究

采用磷酸四钙和磷酸氢钙混合粉末制备了nCa/nP比为1.58的非化学计量羟基磷灰石骨水泥(n-HAC)及其多孔支架材料。结果表明:与nCa/nP=1.67的化学计量羟基磷灰石骨水泥(HAC)相比,n-HAC的凝结时间和抗压强度没有明显的区别。XRD和IR显示:n-HAC与HAC都为羟基磷灰石结构,但n-HAC在Tris-HCl缓冲溶液的降解性明显大于HAC。细胞培养结果表明:成骨细胞在n-HAC和HAC两种材料上的粘附和细胞形态没有明显的区别,但细胞在n-HAC上的增殖率明显高于HAC。将多孔n-HAC支架材料植入兔股骨缺损处,观察其修复骨缺损情况,组织学分析结果表明:新生骨在多孔支架的表面形成,并长入其内部;n-HAC在体内的降解比HAC快,能明显地促进新骨生成。     

New method for speciation analysis of aluminium fluoride complexes by HPLC-FAAS hyphenated technique

Speciation analysis of aluminium in the presented system of HPLC-FAAS hyphenated technique lasts 4 min. Using the bifunctional column in model analysis and using the calculation methods for modelling using the Mineql program enabled the authors to presume that particular forms will be subjected to elution in the following order: (1) AlF₂⁺ and AlF₄⁻, (2) AlF²⁺ and AlF₃⁰ and (3) Al³⁺. Based on the obtained results for model solutions, the presented method enables the determination of aluminium fluoride complexes and Al³⁺ speciation form. The study compares the tendency of occurrence variability of aluminium fluoride complexes and Al³⁺ form, determined based on the results obtained using the HPLC-FAAS hyphenated technique with the trend defined based on the Mineql program calculation method. The method was successfully applied to soil samples.     

Preparation and colloidal behaviour of surface-modified EuF3

Surface-modified EuF₃ nanoparticles has been produced by mixing of NaF and Eu(NO₃)₃ aqueous solutions in the presence of sodium citrate as stabilizer. Transmission electron microscopy and dynamic light scattering has shown citric ions influence on the particle size and morphology. Modified and unmodified EuF₃ samples were characterized by X-ray diffraction, elemental analysis, IR and luminescence spectroscopy. The results indicate that citrate ions bond chemically with EuF₃ particle, forming a layer onto the surface. The layer stabilizes nanoparticle colloids and prevents their aggregation. In the case of modified EuF₃ colloids, reversible precipitation-peptization processes at varying pH values and Cu²⁺ chemosorption by citric layer are revealed.     

全氟己酮中间体全氟丙酰氟及全氟环氧丙烷的合成研究进展

全氟己酮是优良的灭火剂和清洁剂,环境友好且性能优异。本文对其合成工艺进行探究,指出了以六氟丙烯为原料的合成工艺具有工业化的前景,并对六氟丙烯工艺中的重要中间体六氟丙酰氟及六氟环氧丙烷(HFPO)的合成方法进行了分析,指出分子氧液相氧化六氟丙烯制HFPO及使用鼓泡反应器将HFPO异构化成全氟丙酰氟是最有应用前途的工业合成方法。     

钠铝氟化物包覆BaF2材料上转换发光性能

采用水热法合成了一种非稀土上转换发光材料,由钠铝氟化物和BaF2组成。采用X射线衍射(XRD)、傅里叶红外光谱(FTIR)和扫描电镜(SEM)对其进行了表征,分析表明,钠铝氟化物主要以NaF和Na3AlF6两种晶态存在于BaF2晶体表面,形成化学复合,呈现包覆结构。荧光光谱测试表明,样品在583nm可见光和863nm近红外光室温激发下,均能产生304和324nm的宽波段紫外光发射。时间分辨光谱表明,发光均有一个上升和衰减过程,衰减大约自15ms开始,磷光寿命大于18.4ms。借助上转换发光能量转换过程对发光机理进行了研究,分析表明,发光源于量子限制效应的带间光吸收和界面缺陷的光吸收,发光机制属于量子限制效应-界面发光中心复合发光。     

Porous poly(vinylidene fluoride) membrane modified with hyperbranched poly(amine‐ester)

Poly(vinylidene fluoride) (PVDF) membranes were hydrophilic modified with hydroxyl group terminated hyperbranched poly(amine‐ester) (HPAE). Fourier transform infrared spectroscopy (FT‐IR) was used to study the chemical change of PVDF membranes. X‐ray photoelectron spectroscopy (XPS) indicated that some HPAE molecules were retained in PVDF membrane through polymer chain coiling. The presence of HPAE would improve the hydrophilicity of PVDF membrane. Scanning electron microscopy (SEM) was employed to characterize the morphology of different membranes. The thermodynamic stability for PVDF/DMAc/HPAE/Water system was characterized by the determination of the gelation values. Precipitation kinetics for PVDF/DMAc/HPAE/Water system was studied by precipitation time measurement. The water contact angle indicated that the hydrophilicity and the biocompatibility corresponding to protein adsorption of PVDF membrane were improved significantly after blending with hydrophilic HPAE molecules. Copyright © 2011 John Wiley & Sons, Ltd.     

Hyperfine spectrum of NaF

The molecular beam electric resonance technique has been used to conduct a high precision examination of the hyperfine spectrum of ²³Na¹⁹F. Coupling constants for the nuclear electric quadrupole interactions, the spin-rotation interactions, the tensor and scalar spin-spin interactions, and their dependence on vibrational and rotational state have been determined.     

Phase transformations in LnF3-(Ln, Zr)-ZrF4 systems, where Ln = Sm, Eu, Tm, Yb

Phase transformations in LnF₃-(Ln, Zr)-ZrF₄ systems (where Ln = Sm, Eu, Tm, Yb) in the temperature range 700-900 °C have been investigated by chemical and X-ray phase analyses, UV and IR spectroscopy. Synthesis conditions of nonstoichiometric samarium, europium, ytterbium and thulium fluorides, which are products of interaction between LnF₃ and Ln and original substances for the preparation of compounds such as LnZrF₆ are given. The crystal lattice of the fluorozirconates obtained is similar to the Yb₂₇F₆₄ superstructure. Thulium fluorozirconate (TmZrF₆), whose structure is indexed as the Tm₁₃F_32−δ superstructure of hexagonal system, is an exception. For all compounds obtained, the lattice parameters have been calculated and the absorption bands of IR spectra have been interpreted.     

Flow injection analysis as a tool for enhancing oceanographic nutrient measurements—A review

Macronutrient elements (C, N and P) and micronutrient elements (Fe, Co, Cu, Zn and Mn) are widely measured in their various physico-chemical forms in open ocean, shelf sea, coastal and estuarine waters. These measurements help to elucidate the biogeochemical cycling of these elements in marine waters and highlight the ecological and socio-economic importance of the oceans. Due to the dynamic nature of marine waters in terms of chemical, biological and physical processes, it is advantageous to make these measurements in situ and in this regard flow injection analysis (FIA) provides a suitable shipboard platform. This review, therefore, discusses the role of FIA in the determination of macro- and micro-nutrient elements, with an emphasis on manifold design and detection strategies for the reliable shipboard determination of specific nutrient species. The application of various FIA manifolds to oceanographic nutrient determinations is discussed, with an emphasis on sensitivity, selectivity, high throughput analysis and suitability for underway analysis and depth profiles. Strategies for enhancing sensitivity and minimizing matrix effects, e.g. refractive index (schlieren) effects and the important role of uncertainty budgets in underpinning method validation and data quality are discussed in some detail.     

聚偏氟乙烯涂料的研究

用聚偏氟乙烯(PVDF)树脂制备了溶剂型氟碳涂料,筛选并优化了PVDF涂料的溶剂组成。采用丙烯酸树脂对PVDF进行改性,并研究颜填料钛白粉对涂膜性能的影响。结果表明,由甲苯、甲基异丁基酮、乙二醇乙醚乙酸酯、2,2,4-三甲基-1,3-戊二醇单异丁酸酯及邻苯二甲酸二甲酯组成的溶剂体系的涂料综合性能比较好,而丙烯酸树脂和钛白粉的加入明显地改善了PVDF涂膜的性能。