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室温下快速合成了Fe3+掺杂的BiF3超小纳米粒子,只需要反应1 min,较小的Fe3+离子即可替代BiF3晶格中较大的Bi3+离子.随着Fe3+掺杂量的增加,BiF3:Fe3+纳米粒子的粒径不断减小,当Fe3+的掺杂量达到0.119时,可以得到尺寸约为6.9 nm的Fe3+掺杂BiF3超小纳米粒子.此外,Fe3+离子的掺杂使BiF3:Fe3+-x样品的能带结构发生了显著变化.制备的Fe3+掺杂BiF3超小纳米粒子在光催化剂和荧光材料方面具有潜在的应用价值. 相似文献
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通过多种重原子微扰剂和实验条件的选择,成功地实现了C6SCl在数种基质上的RTP发射。发现Pb(Ⅱ)盐是这种RTP发射的最有效的外部重原子微扰剂。在滤纸基质上,以1mol/L Pb(Ac)_2作重原子微扰剂获得了强度高且信/背比亦高的RTP信号,λ_(ex)/λ_(em)=320/496nm。0.2μl点样体积中,C6SCl含量在4~200pmol范围内与RTP信号强度呈良好的线性关系。 相似文献
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The room temperature reaction of Na4Sn2S6 · 5H2O with CoCl2 · 6H2O and 2-(aminomethyl)pyridine (2-AMP) or trans-1,2-diamino-cyclohexane (DACH) leads to crystallization of two compounds with the compositions [Co(2-(aminomethyl)pyridine)3]2 Sn2S6 · 10H2O ( 1 ) and [Co(trans-1,2-diaminocyclohexane)3]2Sn2S6 · 8H2O ( 2 ). In both compounds [Sn2S6]4– anions are present that are charge balanced each by two Co2+ centered complexes. Each of the two CoII cations are sixfold coordinated by six N atoms of three 2-AMP or DACH ligands within slightly distorted octahedra. In compound 1 , the two complexes are linked by one [Sn2S6]4– anion via strong N–H ··· S hydrogen bonds into centrosymmetric charge neutral trimeric units, that are further linked by weak C–H ··· S and N–H ··· S hydrogen bonds into chains that are directed along the a axis. These chains are further joined by N–H ··· O and O–H ··· O hydrogen bonds into a 3D network, with the H2O molecules forming chains along the b axis. The crystal structure of 2 is similar to that of 1 featuring trimeric units which are also linked into chains. Between the chains water molecules are embedded that link the chains into a 3D network. Upon heating 2 in a thermobalance the water and ligand molecules are removed in discrete steps, indicating that compounds with more condensed thiostannate networks will form. 相似文献
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离子液体反应介质中3-羟基丙酸甲酯加氢反应研究 总被引:6,自引:2,他引:4
以室温离子液体[Bmim]PF6作为反应介质,研究了四羰基钴钾K[Co(CO)4]催化3-羟基丙酸甲酯(3-HPM)加氢制1,3-丙二醇(1,3-PDO)的反应,并对反应条件进行了优化.同有机溶剂作为反应介质相比,该体系具有更高的选择性和更好的催化活性,并且产物经水萃取便可实现催化体系的回收利用.在反应温度165℃、氢气压力10.5 MPa、反应时间10 h、咪唑为促进剂的较佳反应条件下,3-HPM的转化率可达99.4%,1,3-PDO的收率可达82.9%,催化剂重复使用3次,1,3-PDO的收率不低于70%.并根据实验结果,提出了可能的催化反应机理. 相似文献
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The new compounds [Ni(L1)][Ni(L1)Sn2S6]n · 2H2O ( I ) and [Ni(L2)]2[Sn2S6] · 4H2O ( II ) containing the macrocyclic ligands L1 (L1 = 1,8-dimethyl-1,3,6,8,10,13-hexaazacyclotetradecane) and L2 (L2 = 1,8-diethyl-1,3,6,8,10,13-hexaazacyclotetradecane) were prepared at room temperature by overlaying an aqueous solution of Na4SnS4 · 14H2O with the [Ni(L1)](ClO4)2 complex dissolved in CH3CN ( I ) or by overlaying a solution of the [Ni(L2)](ClO4)2 complex dissolved in DMSO with an aqueous solution of Na4SnS4 · 14H2O ( II ). The slow interdiffusion of the two solvents guarantees supersaturation in the interface region of the solvents so that crystallization of the compounds occurs. In the structure of I one Ni2+ cation has bonds to S2– anions of the thiostannate anion thus generating chains along [100]. This cation is in an octahedral environment of four N atoms of L1 and two S atoms of the [Sn2S6]4– anion. The second [Ni(L1)]2+ complex exhibits a square-planar coordination geometry. These [Ni(L1)]2+ complexes and water molecules are located between the chains. In the structure of II isolated [Sn2S6]4– anions and [Ni(L2)]2+ cations are observed. The Ni2+ cations are fourfold coordinated by N atoms of the L2 ligand and feature also a square planar environment. 相似文献
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可可碱、咖啡因、茶碱的滤纸基质室温燐光测定 总被引:2,自引:0,他引:2
以快速定量滤纸为基质 ,用KI NaAc为重原子微扰剂 ,建立了测定痕量可可碱、咖啡因、茶碱的滤纸基质室温磷光 (PS RTP)分析法。该法取样量少 ,线性范围宽 ,可可碱、咖啡因、茶碱的线性范围分别为 14 4~5 76 ;5 .4 4~ 6 99;7.2 1~ 36 0ng/斑点 ;检出限分别为 1 14、0 78、1 80ng/斑点。该方法用于巧克力中可可碱、茶叶中咖啡因、氨茶碱药片中茶碱的测定 ,操作简便快速 ,选择性好。标准回收率在 92 8%~ 10 6 %之间 ;相对标准偏差RSD <5 % 相似文献
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碳纳米管在室温熔盐中的电容特性 总被引:1,自引:0,他引:1
研究了碳纳米管在室温熔盐二(三氟甲基磺酸酰)亚胺锂(LiTFSI)-乙酰胺中的电容特性. 将碳纳米管制成薄膜电极, 以LiTFSI-乙酰胺为电解液, 装配成模拟电容器, 用循环伏安和恒流充放电法研究其电化学性能. 结果表明, 碳纳米管在室温熔盐中表现出典型的电容特性, 其比电容为22 F•g-1, 模拟电容器的工作电压可达2.0 V, 具有非常好的循环性能, 循环充放电1000次后容量损失仅10%, 表明室温熔盐是超级电容器非常有前景的新型电解液. 相似文献
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Single crystals of KBaNbS4 have been prepared by the reaction of Nb with an in situ formed melt of K2S3, BaS, and S at 500 °C. Satellite reflections observed in X‐ray diffraction experiments of these crystals indicate the presence of a one‐dimensional lattice distortion. The modulated structure has been solved and refined from X‐ray data using the superspace group approach. KBaNbS4 can be described in the (3 + 1)‐dimensional superspace group Pnma(α00)0s0 with lattice parameters a = 9.187(1), b = 7.001(1), and c = 12.494(1) Å and a modulation vector q = (0, 0.629(1), 0). In the structure the NbS4 tetrahedra are stacked along the a axis and show a slight tilting against each other. The K+ and Ba2+ ions follow this tilting, both are slightly shifted from their positions in the average structure. The modulation does not lead to a significant change in the coordination spheres of the metal atoms. The small effects of the modulation correspond to the relatively weak intensities of the satellite reflections. Results of temperature dependent X‐ray investigations indicate that K+ librates at higher temperatures and the surrounding S2? anions follow this motion. With decreasing temperature the libration of K+ is reduced and the coordination geometry freezes under formation of an incommensurate modulation. The heavier Ba and Nb atoms are also affected by positional modulation of the substructure and accommodate to their environment. 相似文献
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用滤纸基质室温燐光法分析多环芳烃。以醋酸铊TlAc/醋酸铅Pb(Ac)_2(1∶1mol)的乙醇水(50%V/V)溶液为重原子微扰剂,对国产分析滤纸,玻璃纤维滤膜和醋酸纤维滤膜等9种不同的基质材料测定芘的燐光信号强度并进行了比较。对芘、荧蒽、苯并(e)芘、苯并(a)芘、苯并(ghi)芘和晕苯的混合物样品进行了测定。对煤飞灰和燃煤排放物样品中的芘和苯并(a)芘进行了定量分析,并用高效液相色谱法对测定结果进行验证。对芘和苯并(a)芘的检测限分别达到10~(-10)和10~(-9)g数量级。本文还对进一步提高灵敏度的问题进行了讨论。 相似文献
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In this work the usefulness of Modulated Temperature DSC (MTDSC) for characterizing petroleum products is illustrated with
some typical examples of recent applications. Specifically, the reliability of the method is outlined on the basis of the
freezing behaviour of distillate fuels and the thermal analytical characterization of lubricating greases. The results of
experiments performed on the evaporation residue of distillate fuels, aimed at providing insights into the structure of degradation
products, will also be presented. The experiments were carried out using a DSC 2910 module from TA Instruments Inc., upgraded
with the MTDSC option. The samples were exposed to a cyclic heating profile which was generated by an underlying heating (or
cooling) rate of 2°C min−1 while superimposing a sinusoidally varying time-temperature wave with an amplitude of ±0.5°C and a period of 40 s.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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