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21.
A study on the microwave responses of YBCO and TBCCO thin films by coplanar resonator technique 下载免费PDF全文
YBa2Cu3O7(YBCO) thin films have been prepared by
thermal coevaporation on LaAlO3(LAO) substrates, and
Tl2Ba2CaCu2O8(TBCCO) thin films are synthesized
by magnetron sputtering method on LAO substrates. The transition
temperature Tc is 90\,K for YBCO/LAO and 104\,K for
TBCCO/LAO. Microwave responses of the films are studied
systematically by coplanar resonator technique. Energy gaps of the
films obtained are {\it\Delta}0=1.04kBTc for YBCO
films and ${\it\Delta}_0=0.84kBTc for TBCCO films by
analysing the temperature dependence of resonant frequencies of
coplanar resonator. Penetration depth at 0\,K \lambda 0=198nm
for YBCO films and \lambda0 =200nm for TBCCO films could also
be obtained by using the weak coupling theory and two fluid theory.
Results of penetration depth and energy gap confirm the weak coupling
properties of the films. In addition, microwave surface resistances
Rs of YBCO/LAO and TBCCO/LAO are also investigated by
analysing the quality factor and insert loss of the coplanar
resonator. Surface resistance of TBCCO/LAO is less than that of
YBCO/LAO, so that TBCCO/LAO films may have more potential
applications. 相似文献
22.
本文介绍一种为某专用雷达设计制作的工作于L波段的高温超导窄带带通滤波器.该滤波器为10阶微带谐振器级联(CQ)滤波器,引入两个交叉偶合构成一对传输零点形成准椭圆函数传输特性来增加带外陡度.为减小非近临谐振器间寄生耦合对滤波器传输特性的影响,对所采用的谐振器结构进行了精心选择.整个滤波器制作在一块2英寸的MgO衬底YBCO片上,封装后滤波器的整体尺寸为60mm×30mm×18mm.滤波器带宽为5MHz(FBW小于0.4%).实测滤波器带边陡度超过100dB/MHz,在中心频率(3MHz以外频域抑制好于-60dB,滤波器宽带抑制好于-80dB,滤波器最小插损0.3dB. 相似文献
23.
利用固定床热解反应装置和美国CDS-2500快速热解仪对胜利褐煤裂解,制得不同速率热解焦。借助热重分析技术,采用Achar微分法计算热解焦低温氧化增重特性及反应活化能。实验结果表明,快速热解焦的氧化增重量高于慢速热解焦。一级化学反应动力学模型可以很好地描述胜利褐煤焦的氧化增重反应,快速热解焦的氧化活化能较慢速焦低,快速焦更易发生低温氧化反应。 相似文献
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利用射线追踪和福克-普朗克方程,研究了CFETR上驱动电流和功率沉积对低杂波注入位置和耦合波谱的依赖关系,讨论了边界非线性效应对电流驱动与功率沉积的影响,给出了低杂波平行折射率和低杂波注入位置的一个优化值。初步数值计算表明:边界非线性效应会导致驱动电流降低;不考虑低杂波非线性效应时,驱动电流的差异约为6%左右,小于考虑该效应时的差异(~25%)。 相似文献
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Microwave characteristics of MgB2/Al2O3 superconducting thin films were investigated by coplanar resonator technique. The thin films studied have different grain sizes resulting from different growth techniques. The experimental results can be described very well by a grain-size model which combines coplanar resonator theory and Josephson junction network model. It was found that the penetration depth and surface resistance of thin films with smaller grain sizes are larger than those of thin films with larger grain sizes. 相似文献
29.
气相色谱法测定活泥鳅中硫丹及其硫酸盐残留 总被引:1,自引:0,他引:1
建立了检测活泥鳅中α-硫丹、β-硫丹及硫丹硫酸盐残留量的气相色谱法.泥鳅样品经过正己烷-丙酮混合液提取后,转溶至乙腈中,冷冻去脂,再经中性氧化铝小柱净化处理,用丙酮-正己烷(体积比1:2)洗脱,洗脱液用气相色谱-电子捕获检测器检测,外标法定量.标准曲线的线性范围为10~100 ng/mL,相关系数不小于0.998,硫丹定量限为3.3 μg/kg,检出限为1.0 μg/kg.进行4.0,8.0和10.0 μg/kg 3个浓度水平的加标回收试验,回收率为91.3%~105.4%.该方法分析成本低,测定结果准确,能满足常规检测及食品安全监控的需要. 相似文献