spectroscopy. In the Y123 precursorfilmprepared by heating at the rate of 0.2 °C/min in the temperature range from 200 to 250 °C, Cu was distributed uniformly. On the other hand, in the precursorfilmprepared by heat-treating at the rate of 5 °C/min from 200 to 250 °C, Cu was found to be segregated in the vicinity of the surface of the film. This Cu segregation in the precursorfilm might cause the differences
Water-vapor assisted photochemical fabrication of YBa2Cu3O7-x superconducting films with high critical current density
作者:Weibai Bian、Yuanqing Chen、Lingwei Li、Gaoyang Zhao、Na Li、Huimin Wu、Qinghua Ma、Caiying You
DOI:10.1016/j.jallcom.2017.08.230
日期:2017.12
residual organics, and improved the density of the YBCO films. Thus, YBCO superconducting films with improved superconducting properties were obtained after the crystallization process. The YBCO superconducting film that was UV-irradiated for 100 min with water vapor had a maximum critical current density ( J c ) of 8.69 MA/cm 2 (77 K and 0 T).
摘要 提出了一种新型的水汽辅助光化学溶液沉积法制备高性能YBa 2 Cu 3 O 7-x (YBCO)超导薄膜。Y:Ba:Cu:F = 1:2:3:4 的 YBCO 溶液浸涂凝胶薄膜在 150 °C 的低温下暴露于深紫外光下。在紫外线照射过程中,人工引入水蒸气产生具有强氧化能力的羟基自由基(*OH)。之后,获得光子激活的非晶氧化物前体膜。发现高能光子和*OH物种促进了有机基团的裂解,增强了残留有机物的去除,提高了YBCO薄膜的密度。因此,在结晶过程后获得了具有改进的超导性能的 YBCO 超导薄膜。
Desilylation Induced by Metal Fluoride Nanocrystals Enables Cleavage Chemistry In Vivo
equilibrium concentrations of fluoride are often <1 mM. Here we make good use of this minimum amount of fluoride and unveil that metal fluoride nanocrystals could effectively induce desilylation cleavagechemistry, enabling controlled release of fluorophores and drug molecules in test tubes, living cells, and tumor-bearing mice. Biocompatible PEG (polyethylene glycol)-coated CaF2 nanocrystals have been
金属氟化物纳米晶体由于其独特的物理化学性质而被广泛用于生物医学研究。由于溶解度平衡,金属离子和氟化物从纳米晶体的释放是固有的。它曾经被认为是一个缺点,因为它与金属氟化物纳米晶体的分解和功能有关。已经开发了许多策略来稳定纳米晶体,氟化物的平衡浓度通常 <1 mM。在这里,我们充分利用了这种最少量的氟化物,并揭示了金属氟化物纳米晶体可以有效地诱导脱甲硅烷基裂解化学,从而能够在试管、活细胞和荷瘤小鼠中控制释放荧光团和药物分子。生物相容性 PEG(聚乙二醇)涂层 CaF 2已经制备了纳米晶体来测定脱甲硅烷化诱导的功能分子受控释放的效率。我们将该策略应用于单甲基 auristatin E (MMAE) 的前药激活,显示出显着的抗癌作用,而副作用几乎可以忽略不计。总之,这种去甲硅烷基化诱导的裂解化学利用了赋予金属氟化物纳米晶体新的扰动或激活功能以用于进一步生物应用的缺点。
Numerical study on crystal growth process in YBCO film fabricated by TFA-MOD method
metal-organic deposition (MOD) process using precursor solution of trifluoroacetates (TFAs) is one of the most promising low cost non-vacuum methods. However, details of the growthprocess and the mechanism of 123-crystal growth are still unknown. To clarify the growth mechanism of 123-film, the growthprocesses of 123-crystals were studied by the experimental method and the numerical method. Microstructures of
摘要 为了制备 YBa 2 Cu 3 O 7− X (1 2 3) 薄膜的高 J c 涂层导体,使用三氟乙酸盐 (TFA) 前驱体溶液的金属有机沉积 (MOD) 工艺是最有前景的低成本非金属材料之一。 -真空方法。然而,生长过程的细节和 123 晶体生长的机制仍然未知。为阐明123薄膜的生长机理,采用实验方法和数值方法研究了123晶体的生长过程。通过透射电子显微镜 (TEM) 观察在 LaAlO 3 (LAO) 衬底上生长 123 晶体过程中淬火的样品,揭示了生长 123 晶体的微观结构。采用c轴和a轴生长速率函数,通过二维数值方法模拟了具有不同晶体取向的多面123晶体的生长过程。通过模拟可视化了 123 晶体的生长过程和微观结构。研究了晶界的曲折、优选取向晶体的过度生长以及成核晶体和颗粒初始分布的影响。
Core–shell BaYbF<sub>5</sub>:Tm@BaGdF<sub>5</sub>:Yb,Tm nanocrystals for in vivo trimodal UCL/CT/MR imaging