The Effect of the Oxygen Exchange at Electrodes on the High-Voltage Electrocoloration of Fe-Doped SrTiO3 Single Crystals: A Combined SIMS and Microelectrode Impedance Study

The effect of the electrode material on the high voltage stoichiometry-polarization (electrocoloration) of Fe-doped SrTiO₃ single crystals has been studied. For different electrode materials (150-nm Ag/15-nm Cr and 150-nm Au/15-nm Cr) secondary ion mass spectrometry (SIMS) was used to measure the depth profile of the ¹⁸O-isotope after high-field stress. The results were compared with spatially resolved impedance measurements on electrocolored Fe-doped SrTiO₃ single crystals. For Au/Cr as well as Ag/Cr electrodes a large dc voltage leads to moving color fronts which are usually correlated with a pronounced stoichiometry polarization of the samples due to electrodes blocking the ionic current. However, the local impedance measurements demonstrate that the conductivity profiles near the cathode depend on the electrode material. This finding is in accordance with the SIMS measurements which indicate that the Ag/Cr-electrodes are, in contrast to Au/Cr-electrodes not completely inactive for the oxygen incorporation into the Fe-doped SrTiO₃. The results are discussed in terms of defect chemical models.     

三相变四相电力变压器的阻抗理论研究

分析了三相变四相电力变压器中性点接地条件及三相输入阻抗平衡条件,提出了设计这种变压器的绕组阻抗关系理论,并进一步讨论了这种变压器实施的绕组布置方案。     

Enhanced studies on the mechanism of gas selectivity and electronic interactions of SnO2/Na-ionic conductors

The selectivity of metal oxide gas sensors (MOG) can be improved significantly by forming composites with solid ionic conductor additives. First investigations were done using model composites of SnO₂/Natrium Super Ionic Conductor (NASICON) with the result of a huge sensitivity enhancement to substances ending with R–OH, R–HO or R–COOH groups and a reduction of sensitivity to other gas components. This selectivity of the new composite to those functional groups could be confirmed by catalytic conversion measurements with FTIR-spectroscopy at three gas components, respectively. The specific conductivity of the NASICON containing composites is significantly lower than that of pure SnO₂. Advanced studies show that the activation energy of the bulk-conductivity increases by approximately 30% in the presence of NASICON. In spite of high volume parts of NASICON (20%), no polarization effects were found (a complete Ohmic current–voltage behavior) and mainly the resistive part of the electrical impedance is influenced.     

C型单翻翻车机端环优化工艺设计分析

通过对端环的结构和使用性能的分析，重点论述在保证设计要求和使用性能的前提下，从传统的机床入手，采用非传统工艺，实现产品的加工。并重点在组立焊接、支撑加固、装卡工艺孔、测量、加工等方面提出端环的加工方法及注意事项。     

经济耐候钢的研究

系统研究了Mn、Cu含量及腐蚀环境体系对协同作用的影响,并利用电化学测试、扫描电镜、XRD等材料分析技术对带锈电极的腐蚀行为、锈层组成、结构和性质进行了深入分析,阐述了Mn-Cu合金化协同作用的机制;利用Mn-Cu合金化的协同作用,成功开发出Mn-Cu型经济耐候钢和实现工业化试生产。实验表明：热轧Mn-Cu钢具有良好的耐候性,其耐候性略优于传统的09CuPTiRE和SPA-H耐候钢。     

电阻加载偶极天线阻抗带宽及脉冲辐射特性研究

分析了偶极天线电阻加载方面的若干问题，包括不同电阻加载方式阻抗频率特性比较，连续与离散串联集中电阻加载脉冲辐射特性比较，证明其它加载方式具有与Wu-King电阻加载相似的特性，与未加载偶极天线相比，阻抗带宽较宽，辐射脉冲失真较小。     

Matlab求解方同轴波导的截止波长和特性阻抗

采用有限差分法利用Matlab求解了方同轴波导的特性阻抗和高次模的截止波长，并将数据与国外文献数据进行了对比，证明了有限差分法结合Matlab在分析简．单截面的同轴波导时是简单可行的，而且计算精度较高，通用性强，可以用于传输线工程问题的设计和计算。最后计算了矩形同轴线的相关数据用于与方形同轴线作对比。     

柱形等离子体辐射体输入阻抗测量

通过研究等离子体作为电磁波传导媒质的基本物理原理,可知表面波激发的柱形等离子体在特定条件下,可以代替传统的金属用于构成最基本的辐射振子。针对此等离子体辐射体为有源天线的特点,结合传输线阻抗匹配的原理,设计实验对其输入阻抗进行测量,得到符合理论分析的初步结果。对等离子体作为辐射体传输电磁波的研究具有重要的参考价值。     

折合偶极子天线与金属的距离对天线性能的影响

通过Ansoft HFSS 9.0和Matlab软件分析有限尺寸金属片对折合偶极子天线性能的影响。采用矩形且与天线长度比约1.25的有限尺寸金属片,水平对称放置于天线一侧。天线采用结构简单、输入阻抗易于调试的折合偶极子天线。仿真结果表明,通过调整折合偶极子天线与金属片之间的距离可以调节天线的辐射方向,实现较高的增益和阻抗周期变化。此结果已在实际应用中得到验证并可为RFID便携式天线等设计提供参考。     

1.3GHz 0.25μm CMOS低噪声放大器的设计

设计了一种基于0．25μm CMOS工艺的共源共栅型1．3GHz的LNA。从噪声优化、增益及阻抗匹配角度详细分析了电路的设计方法，讨论了寄生电容Cgd、C_match_in及共栅管沟道宽度W2对LNA性能的影响。采用ADS软件，对W2进行扫描和对LNAS参量和噪声系数进行仿真测试结果表明：该LNA在1．3GHz的工作频率下．具有良好的性能指标，噪声系数fN为1．42dB，增益S21为13．687dB．匹配参数S11为-14．769dB，S22为-14．530dB，反向隔离度S12为-52．955dB。