YBCO的空分纯化机理与应用

剖析了 YBCO在高温的氧化还原反应过程和伴随发生的吸氧、放氧过程以及它们对空气分离和气体纯化的贡献。也给出了相关的中试实验结果。作为高温超导材料一种新的应用是有重要意义的     

暂态热重法分析混合导电材料YBa_2Cu_3O_(7-δ)的透氧性能

用暂态热重法研究了 YBa2 Cu3O7-δ(YBCO)粉末在不同的温度下 N2 → O2 → N2 交变气流中的吸氧、脱氧过程 ,估算了其在不同温度下的氧吸附速率、氧脱附速率。结果表明 ,YBCO对氧有强烈的选择吸附性 ,并且其吸氧、脱氧过程是可逆的 ,氧吸附过程较迅速 ,而氧脱附过程则较缓慢 ;氧吸附或氧脱附过程在开始阶段是表面扩散 ,以后主要是体扩散。     

YBCO熔融织构准单晶中的进氧和脱氧扩散研究

采用热重法研究了YBCO熔融织构准单晶中氧的化学扩散过程. 与以往的实验不同，采用固定 氧偏压变化温度的方法获得氧浓度梯度. 拟合实验所得重量等温弛豫曲线可知，在375—600 ℃温区内，熔融织构准单晶的氧化学扩散系数比单晶体高出约50％，但都约为10^{-10c m2s-1，激活能为～1eV. 对YBCO熔融织构准单晶中的进氧和脱氧研 究表 明两者具有相同的速率，证实实验过程中环境氧分压的改变会导致进氧和脱氧过程不一致. 关键词： 高温超导 氧扩散 熔融织构 热重法}     

YBa_2Cu_3O_(7-x)分子筛的制备与应用

用不同原料或加入添加剂的方法研究了 YBa2 Cu3O7- x( YBCO)对氧的“呼吸”性能的影响。研究发现 ,加入 5 %～ 1 0 %的萘作为添加剂是提高 YBCO分子筛除氧效果的有效途径。利用加萘的YBCO分子筛已经生产出高纯氮气     

固相反应法制备高温超导材料YBCO实验的研究

介绍了固相反应法制备高温超导材料钇钡铜氧（YBCO）的实验方法,并研究了YBCO样品制备过程中不同烧结时间对样品的超导转变温度Tc及超导转变宽度ΔTc的影响。给出了实验过程中合适的烧结温度和烧结时间的参考值。     

原位电阻法研究MTG-YBCO的吸氧扩散

本工作采用原位电阻驰豫方法研究了熔融织构（MTG）YBCO（YBa2Cu3O7_δ＋0.4molY2BaCuOz)复相体系中氧（缺位）扩散。实验结果表明：MTG－YBCO生长过程中保留的非氧缺位类缺陷能加速吸氧进程,经930℃高温退火的MTG－YBCO的吸氧速率比未经高温退火者小。高温火MTC－YBCO在400－550℃温区吸氧而致的电阻弛豫可近似用一热激活过程一氧（缺位）扩散描述,氧扩散激活能力－0.73eV,在400－550℃温区氧的化学扩散系数为－10^-5cm^2sec^-1。所得晶格扩散激活能和化学扩散系数分别处于文献报道相应值的低值区和高值区。这种行为可能和MTG－YBCO材料中复杂的缺陷状态有关,缺陷提供了氧的局域快扩散通道,从而一定程序上影响氧（缺位）迁移动力学。     

利用BFEL研究高温超导钇钡铜氧薄膜的中远红外特性

 报导了一种钇钡铜氧（YBCO）高温超导薄膜中远红外光探测器。在中远红外波段，利用北京自由电子激光对其响应特性进行了实验研究。对于微桥尺寸为210μm×70μm×0.3μm的样品,测量了电压响应、谱响应和时间响应。实验表明，在液氮温度下工作的YBCO高温超导光探测器不仅具有快速响应、较高灵敏度的特点，而且具有良好的宽带特性和较好的稳定性。     

电镀铜对YBCO超导带材临界电流影响的研究

钇系超导带材(YBCO)由于载流能力强、不可逆场高,是近年来高温超导材料领域的研究热点,并在电力行业实现示范应用。YBCO超导带材由基底、缓冲层、超导层和保护层组成,可通过电镀铜工艺实现保护层的制备。目前,有关电镀铜对YBCO超导带材临界电流的影响还鲜有报道。因此,本研究对比了镀铜前后YBCO超导带材的表面形貌和临界电流。实验结果表明:电镀铜在提高带材机械强度的同时,对其超导电性并无明显影响。     

二代YBCO带材接头电学性能低温实验研究

针对第二代YBCO高温超导带材接头进行相关电学性能测试,根据对YBCO带材与其他材料焊接接头模型进行电流转移分析,得出接头电阻与YBCO焊接面的电阻率、焊料种类有关。再进行YBCO带材临界电流测试,YBCO二层叠临界电流测试,YBCO带材不同搭接方式的临界电流以及接触电阻测试和不同焊料对YBCO带材接触电阻影响的实验,实验得出YBCO带材的接触电阻与焊料的选择无关,与焊接面有关。     

稀土元素替代Y对YBa_2Cu_3O_(7-δ)氧吸附性能的影响

用热重法研究了RBa2Cu3O7-δ(R=Gd、Er、Eu、Dy、Sm、Ho和Nd)及Y1-xLaxBa2Cu3O7-δ(x=0.1,0.5和1.0)共10种材料在高温下的氧吸附—脱附性能。结果表明,随着温度的升降循环,仅NdBa2Cu3O7-δ(R=Gd)和Y1-xLaxBa2Cu3O7-δ的氧吸附—脱附性能有较好的重复性,其余的6个样品的重复性都很差;并且这10种样品的质量变化率都没有YBCO的大。     

GROWTH MODE OF Cu-RICH PARTICLES ON LASER-ABLATED YBa2Cu3O7 THIN FILMS

The microstructure of the laser-ablated YBa₂Cu₃O₇ (YBCO) thin film deposited on heated (100) SrTiO₃ substrate was examined by transmission electron microscope. The par-ticles on the film mainly consist of CuO and few CuYO₂. Most of these non-superconducting particles nucleate on or near the surface of the film and protrude about 100-400 nm in height, A large amount of a-axis YBCO grains also exist in the film, which nucleate at the substrate surface and grow perpendicularly above the c-axis YBCO film. The YBCO thin film deposited under low oxygen pressure has very different microstructure compared with YBCO thin film deposited under high oxygen pressure.     

GROWTH MODE OF Cu-RICH PARTICLES ON LASER-ABLATED YBa2Cu3O7 THIN FILMS

The microstructure of the laser-ablated YBa₂Cu₃O₇ (YBCO) thin film deposited on heated (100) SrTiO₃ substrate was examined by transmission electron microscope. The par-ticles on the film mainly consist of CuO and few CuYO₂. Most of these non-superconducting particles nucleate on or near the surface of the film and protrude about 100-400 nm in height, A large amount of a-axis YBCO grains also exist in the film, which nucleate at the substrate surface and grow perpendicularly above the c-axis YBCO film. The YBCO thin film deposited under low oxygen pressure has very different microstructure compared with YBCO thin film deposited under high oxygen pressure.     

Effects of activated carbon properties on the adsorption of naphthalene from aqueous solutions

The aim of this work was to investigate the role of porous and chemical heterogeneities of activated carbons in the adsorption of naphthalene from aqueous media. A commercially available activated carbon was used as the adsorbent, and its surface heterogeneity was systematically altered by heat treatment at 450 and 850 °C, obtaining a series of carbons with various oxygen contents and similar surface functionalities. The results confirmed that the adsorption of naphthalene depends strongly on the pore size distribution of the adsorbent, particularly narrow microporosity. Moreover, oxygen functionalities reduced the accessibility and affinity of naphthalene to the inner pore structure via formation of hydration clusters. Consequently, the hydrophobic/hydrophilic character of the adsorbent is important, since it dominates the competitive adsorption of water. Adsorbents with a high non-polar character (i.e., low oxygen content) have proven to be more efficient for naphthalene adsorption.     

平均价电子数与掺杂Y_1Ba_2Cu_3O_(7-δ)体系超导电性的关系

文中尝试引进平均价电子数对掺杂Y1Ba2Cu3O7-δ(YBCO)体系超导电性进行分析。结果表明,掺杂YB-CO体系的平均价电子数Zv与转变温度Tc、临界电流密度Jc之间有较好高斯分布规律。因此,提出用平均价电子数作为提高掺杂YBCO体系超导电性的一个新依据。这对今后制备出具有更高Tc、Jc的掺杂YBCO超导氧化物有很好的指导意义。     

批量化制备高性能单畴YBCO超导块

用顶部籽晶熔融织构生长法（TSMTG）批量制备了30mm直径的YBCO单畴超导块材，使用一种六面控温的箱式炉和一台改进的坩埚炉进行晶体生长，采用了高压氧化退火工艺对生长出的YBCO晶体进行后处理，与流动氧化工艺相比，在保持样品超导性能不变的情况下高压氧化大大节约了用氧量，缩短了氧化退火时间，提高了生产效率，大多数单畴超导块在77k和0.5T的磁场下的磁悬浮力超过10N/cm^2，其中最高值达到了15N/cm^2，目前我们巳具备了年生产1000块30mm直径优质单畴导块的能力。     

HgO-added YB<Subscript>a2</Subscript>Cu<Subscript>3</Subscript>O<Subscript>7</Subscript>−δ superconductors

The HgO-added YB_a2Cu₃O_7−δ (YBCO) superconductor has been studied for its structural and superconducting properties. Polycrystalline YBCO samples were synthesized through solid-state reaction method by adding HgO in different concentrations without using oxygen annealing. All the samples showed a sharp superconducting transition temperature around 90 K. The X-ray diffraction patterns of all the samples revealed monophasic Y-123 nature. The structural studies were carried out by neutron scattering and Rietveld analysis. The neutron scattering revealed that Hg is not incorporated in the Y-123 system and has shown optimum oxygen concentration. The significant role played by the HgO is to provide oxygen ambient through its decomposition, thus changing the oxygen balance in favour of high Cu-valence state.