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991.
Nano-crystalline FeOOH particles(5~10 nm) have been uniformly mixed with electric matrix of single-walled carbon nanotubes(SWNTs)for forming FeOOH/SWNT composite via a facile ultrasonication method. Directly using the FeOOH/SWNT composite(containing 15 wt%SWNTs) as anode material for lithium battery enhances kinetics of the Li+insertion/extraction processes, thereby effectively improving reversible capacity and cycle performance, which delivers a high reversible capacity of 758 mAh g-1under a current density of 400 mA g-1even after 180 cycles, being comparable with previous reports in terms of electrochemical performance for FeOOH anode. The good electrochemical performance should be ascribed to the small particle size and nano-crystalline of FeOOH, as well as the good electronic conductivity of SWNT matrix. 相似文献
992.
Ba0.9R0.1Co0.7Fe0.225Ta0.075O3-δ(BRCFT, R = Ca, La or Sr) membranes were synthesized by a solid-state reaction. Metal cation Ca2+,La3+or Sr2+doping on A-site partially substituted Ba2+in BaCo0.7Fe0.225Ta0.075O3-δoxides, and its subsequent effects on phase structure stability, oxygen permeability and oxygen desorption were systematically investigated by XRD, TG-DSC, H2-TPR, O2-TPD techniques and oxygen permeation experiments. The partial substitution with Ca2+, La3+or Sr2+, whose ionic radii are smaller than that of Ba2+, succeeded in stabilizing the cubic perovskite structure without formation of impurity phases, as revealed by XRD analysis. Oxygen-involving experiments showed that BRCFT with A-site fully occupied by Ba2+exhibited good oxygen permeation flux under He flow, reaching about 2.3mL min-1 cm-2at 900 ℃ with 1 mm thickness. Of all the membranes, BLCFT membrane showed better chemical stability in CO2, owing to the reduction in alkalinity of the mixed conductor oxide by La doping. In addition, we also found the stability of the perovskite structure under reducing atmospheres was strengthened by increasing the size of A-site cation(Ba2+La3+Sr2+Ca2+). 相似文献
993.
In this paper, poly(amide-6-b-ethylene oxide) (Pebax1657)/SAPO-34 mixed matrix membranes (MMMs) were prepared by solvent-evaporation method with acetic acid as a novel solvent. CO2, N2, CH4 and H2 permeation properties were investigated, and the physical properties of Pebax/SAPO-34 MMMs were characterized by XRD and SEM. At low SAPO-34 content, it was homogeneously distributed in the Pebax ma- trix, and then precipitated and agglomerated at high SAPO-34 content. The crystallinity of Pebax phase in Pebax/SAPO-34 MMMs decreased initially and then rebounded as a result of phase separation. With the increase of transmembrane pressure difference, CO2 permeability was en- hanced due to the effect of pressure-induced plasticization. Owing to the happening of stratification, the CO2 permeability of Pebax/SAPO-34 MMMs (50 wt% SAPO-34) increased to 338 Barrer from 111 Barrer of pristine Pebax, while the selectivities of CO2/CH4 and CO2/N2 were almost unchanged. Compared with the pristine Pebax, the gas separation performances of Pebax/SAPO-34 MMMs were remarkably enhanced. 相似文献
994.
建立了由多种金属离子和小分子配体组成的多相人体血浆热力学平衡模型。模拟研究了Pu4+在血浆的形态分布及二乙三胺五乙酸(DTPA)和CO32-、Citrate3-浓度对细胞液中Pu4+形态分布的影响。血浆中的低浓度Pu(Ⅳ)易以Pu(OH)4(aq)的形态蓄积在肝脏中,钚浓度升高则形成沉淀Pu(OH)4(s)难以排出。在[DTPA]=2.5×10-5mol·L-1时,血浆中水溶性小分子[Pu(OH)DTPA]2-含量达到最高并保持稳定。酸性条件下随着[Citrate3-]的升高,血浆中Pu4+与Citrate3-结合形成可溶性的[PuCitrate2]2-和[PuCitrate]+离子化合物。[DTPA]4.6×10-5mol·L-1时,血浆中的DTPA以与Ca2+、Mg2+结合的[CaHDTPA]2-、[Ca2DTPA]-、[CaDTPA]3-、[MgHDTPA]2-、[MgDTPA]3-小分子结合态为主。 相似文献
995.
以反渗透、纳滤为代表的膜技术已广泛应用于海水和苦咸水脱盐等水处理过程。通过将纳米颗粒添加到传统复合膜基质中,可以制备具有高分离性能和耐污染性的新型膜材料。混合基质膜结合了无机材料及有机聚合物各自的优点,是新型水处理膜材料的发展方向。本文综述了添加无机纳米颗粒的混合基质反渗透、纳滤及正渗透膜的研究进展,详细讨论了不同类型纳米材料的性质和功能,分析了表面有机改性对改善纳米材料分散性以及与聚合物基质相容性的作用,探讨了纳米材料添加方式和膜制备方法对膜结构和性能的影响。在此基础上,进一步探究了混合基质膜的成膜及分离机理,归纳了目前研究中存在的主要问题,并对未来水处理膜材料的研发方向提出了建议。 相似文献
996.
A new mixed-valence cyanide-bridged complex, Br3Fe(μ-NC)RuBr(dppm)2(dppm = bis(diphenylphosphino)methane), was obtained through the reaction between trans-(dppm)2ClRuCN and FeBr3. Its crystal structure was characterized. Electronic absorption spectra indicate the existence of metal-to-metal charge transfer(MMCT) and this complex is Class Ⅱ mixed valence complexes according to the classification of Robin and Day. Magnetic analysis shows it is paramagnetic. 相似文献
997.
A new mixed-valence heterometal cluster Mo8VW2VIO26(C5H5N)8·2H2O has been synthesized under solvothermal conditions and characterized by X-ray single-crystal diffraction, IR, UV-vis and XPS spectroscopy. The title compound crystallizes in the triclinic system, space group P1 with a = 11.708(3), b = 12.018(4), c = 13.316(4) , a = 112.184(4), β = 97.844(4), r = 110.043(3)o, V = 1551.9(8) 3 and Z = 1 at 293(2) K. The final full-matrix least-squares refinement converged to R = 0.0414 for 4460 observed unique reflections with I 2σ(I) and w R = 0.1290 for all data(5352) and S = 1.015. In addition, its thermal stability and fluorescent property have also been investigated. 相似文献
998.
Polyamide I1 (PAll) and its nanocomposites with different organoclay loadings were prepared by melt-compounding and subsequent pelletizing. The crystal phase transitions of PAl 1 and its clay nanocomposites were investigated by variable-temperature X-ray diffraction. It was found that the Brill transition of the nanocomposite was 20 K higher than that of the neat PAl 1 for both heating and cooling processes. The PAl 1 d-spacings of the nanocomposites were observed to be smaller than those of the neat PAl 1 for melt crystallization. The constraints imposed by the addition of layered clay, restricting the thermal expansion of the polymer chains, are probably responsible for such a reduction of the d-spacing. 相似文献
999.