Chemical Design and Thin Film Preparation of p-Type Conductive Transparent Oxides

Chemical design to find a new transparent conductive oxide having p-type conductivity has been proposed. Following the chemical design, we have selected CuGaO₂ and CuAlO₂ as candidate materials. CuGaO₂ thin films were prepared on silica glass substrates by RF sputtering method. The optical band gap of the film was estimated to be 3.4 eV. Positive sign of Seebeck coefficient demonstrated the p-type conductivity of the film. The dc conductivity of the film was 5.6 × 10^–3S·cm^-1 and the activation energy was 0.22 eV at room temperature. Because of rough texture of the film, the observed conductivity was not an intrinsic property of the material. Further, CuAlO₂ thin films were prepared by laser ablation. The film deposited in O₂ atmosphere of 1.3 Pa at 690°C showed higher optical transmission in visible and near-infrared regions than previously reported. Contribution of Cu 3d components to upper edge of valence band in CuGaO₂ and CuAlO₂ were confirmed by photoemission spectroscopic measurements.     

Defect-Property Correlations in Garnet Crystals. *VII: The Electrical Conductivity and Defect Structure of Yttrium Aluminum and Yttrium Iron Garnet Solid Solutions

The conduction mechanisms in yttrium aluminum and yttrium iron garnet solid solutions have been studied as a function of temperature, iron concentration and partial pressure of oxygen. At low concentrations of iron, ac conductivity and ionic transference measurements show the solid solution to be a mixed ionic-electronic conductor with an ionic mobility characterized by an activation energy of 2.6–2.8eV and a p-type electronic conductivity with activation energy of 3.0–3.3eV. High concentrations of iron cause a dramatic increase in the electrical conductivity connected with the formation of an Fe impurity band found to lie 1.9eV below the conduction band. Transport through this band is via an activated hopping process with an activation energy of 0.7eV for 6 fraction percent Fe. A defect model is presented which is consistent with our experimental observations including the conductivity maxima obtained at high PO₂'s for high Fe levels.     

Nonstoichiometry and Electrical Conductivity of Nanocrystalline CeO{2 - x}

We synthesized dense CeO polycrystals of 10 nm grain size and characterized their electrical conductivity, in order to determine whether the defect properties of nanocrystalline solids fundamentally differ from those of conventional materials. The nanocrystals exhibit enhanced electronic conductivity, greatly reduced grain boundary impedance, and a heat of reduction more than 2.4 eV lower per oxygen vacancy compared to their coarse-grained counterparts. We propose that defect formation at low energy grain boundary sites is responsible for these properties, and that nanocrystalline oxides represent bulk materials possessing the defect thermodynamics of interfaces.     

熔融碳酸盐燃料电池阴极材料的导电性

通过交流阻抗方法研究了熔融碳酸盐燃料电池阴极材料锂镍氧化物、锂钴氧化物和锂铁氧化物的导电性能。结果表明:锂镍氧化物电极的导电性最好,锂钴氧化物电极的导电性次之,锂铁氧化物电极的导电性最差;它们的导电性都随着温度的升高而按指数规律增加;在合成锂钴氧化物(或锂铁氧化物)的过程中,使Li2CO3轻微过量,可以提高锂钴氧化物(或锂铁氧化物)电极的导电性,而且在同一温度下,随着nLi∶nCo(或nLi∶nFe,摩尔比)值的增大,锂钴氧化物(或锂铁氧化物)电极的导电性显著增加。     

Low‐resistive and transparent AZO films prepared by PLD in magnetic field

Al₂O₃‐doped ZnO (AZO) thin films have been deposited onto glass substrates using a split target consisting of AZO (1 wt%) and AZO (2 wt%) by pulsed laser deposition with an ArF excimer laser (λ = 193 nm, 15 mJ, 10 Hz, 0.75 J/cm²). By applying a magnetic field perpendicular to the plume, the lowest resistivity of 8.54 × 10^?5Ω·cm and an average transmittance exceeding 91% over the visible range were obtained at a target‐to‐substrate distance of 25 mm for approximately 279‐nm‐thick AZO film (1.8 wt%) grown at a substrate temperature of 230 °C in vacuum. From cross‐sectional TEM observations and the XRD spectrum, a reason why the low resistivity (54 × 10^?5Ω·cm) was reproducibly obtained was considered to be due to the fact that a disorder of crystal growth originating in the vicinity of the interface between the substrate and the film was suppressed by application of the magnetic field and the c‐axis orientation took preference, giving rise to the increase of mobility. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(2): 40–45, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20026     

智能变电站时钟同步系统中的透明时钟原理分析与实验

高精度的时钟同步对于保证智能变电站继电保护的正常工作具有举足轻重的作用。基于IEEE 1588v2标准的透明时钟的应用可进一步提高智能变电站时钟同步的精度。分析了基于IEEE 1588v2的透明时钟基本原理,从主时钟负载、网络拓扑变化的适应性和同步精度等方面对对等(P2P)透明时钟和端到端(E2E)透明时钟进行了比较和实验研究。结果表明,2种透明时钟均能满足智能变电站1μs的同步精度要求,但P2P透明时钟的整体性能要优于E2E透明时钟,因此建议在智能变电站中采用P2P透明时钟。     

Modeling and Characterization of Electrical Transport in Oxygen Conducting Solid Electrolytes

A model for the electrical conductivity in acceptor-doped oxides which involves an association between the acceptor-dopants and oxygen vacancies resulting in donor centers is considered. The model relates the behavior of the electrical conductivity with the temperature, ambient atmosphere and band structure. The predictions of the model are compared to experimental data for ZrO₂:16% Y and SrCeO₃:5% Yb oxygen conductors and some band structure parameters have been determined.     

不可逆电穿孔时组织电导率变化对电场和温度的影响

为了研究不可逆电穿孔过程中组织电导率对组织内电场分布及温度的影响,采用有限元分析软件COMSOL建立了小鼠肝脏的球形肿瘤及椭球形肿瘤的数值模型;通过改变组织的电导率,得到肿瘤及正常组织内不可逆电穿孔电场、温度的分布情况。结果表明:组织电导率随着穿孔过程的发展逐渐增大。组织电导率变化前后,2种肿瘤模型中的各项数据如下:1)不可逆电穿孔电场消融的肿瘤体积与肿瘤总体积之比分别从0.867 7升至0.927 0(球形肿瘤)以及从0.451 1升至0.772 1(椭球形肿瘤);2)不可逆电穿孔电场造成正常组织损伤的体积与肿瘤总体积之比分别从0.745 9降至0.678 2(球形肿瘤)以及从0.816 4降至0.603 6(椭球形肿瘤);3)温升1℃的正常组织的最大体积只有肿瘤体积的1.16%,说明正常组织的温升对组织整体温度变化的影响较小。因此,组织不可逆电穿孔过程中,增大电导率能在促进电脉冲对肿瘤的消融效果的同时减小其对正常组织的损伤,且脉冲作用造成的组织温升不会造成组织的热损伤。     

化学交联方式对聚乙烯水树枝老化特性的影响

为研究化学交联对聚乙烯水树枝老化特性的影响,选用低密度聚乙烯（LDPE）、过氧化物交联聚乙烯、硅烷交联聚乙烯作为试验材料。采用水针电极法培养水树枝,用金相显微镜观测水树枝的形态,并统计了水树枝的尺寸和引发率;同时观测了试样的结晶形态,测定了试样的结晶度、交联度和杂质质量分数,并对比分析了交联前后及不同交联方式试样的电气...     

Featured Article: Use of Microhotplates in the Controlled Growth and Characterization of Metal Oxides for Chemical Sensing

Microhotplates are micromachined platforms with integrated heaters and contact electrodes that can be used as miniature substrates for metal oxide film growth. Fabricated as arrays, they enable efficient combinatorial studies to be performed on a single chip. A variety of growth methods are compatible with their use, including evaporation, sputtering, chemical vapor deposition, and deposition from pastes or sol gels using screen printing, drop deposition, or spin-coating. The microheater on each element may be used to control the temperature during deposition or for a post-annealing step such as sintering, while the film contact electrodes serve as a built-in monitor of the fabrication process. In chemical vapor deposition using arrays, the elements with heaters set above the lowest nucleation temperature for a given precursor are the only ones that will have film deposited on them, resulting in a kind of self-lithography. This review gives examples of different methods of film growth that have been employed on microhotplates with applications for chemical sensing, with an emphasis on the chemical vapor deposition method.     

化学清洗时过热器氧化皮剥落部位基材腐蚀试验研究

锅炉过热器氧化皮发生局部剥落的部位,在进行化学清洗时会发生局部电化学快速腐蚀的情况。工程清洗后的割管和试验室的验证性模拟清洗试验,均发现了局部氧化皮剥落部位出现了深度在400 μm以上的腐蚀坑,且这种腐蚀主要在铁素钢如T22、12Cr1MoV、T91中发生。通过电化学腐蚀试验装置,开展了对这种腐蚀的监测评价和腐蚀控制工艺研究。选取T22、12Cr1MoV、T91等3种过热器管样,进行氧化皮清洗溶解试验,测量氧化皮清洗过程中完整氧化皮管样电极和裸露金属电极之间腐蚀电流密度,并通过对比试验考察清洗液加入还原剂后的腐蚀电流密度变化情况。研究结果表明,试验所用材料氧化皮脱落部位化学清洗时的局部腐蚀速率是标准规定值的数十倍,可通过及时补加还原剂抗坏血酸的方法加以控制。     

表层非线性电导盆式绝缘子表面电荷分布与沿面放电特性

盆式绝缘子表面电荷积聚是影响直流气体绝缘输电管道(direct current gas insulated transmission line,DC-GIL)电场分布与沿面闪络的重要因素,因此探究绝缘子表面电荷积聚机理并提出调控方法,进而改善绝缘子沿面电场分布具有重要意义。该文搭建缩尺直流GIL绝缘子试验平台,研究不同Si C质量分数(23.1%、37.5%、47.4%)的非线性电导涂层对直流电压、金属微粒附着和极性反转工况下盆式绝缘子表面电荷分布与沿面闪络特性的影响规律。结果表明：环氧基Al₂O₃绝缘子的表面电荷极性取决于气固侧电流密度博弈结果,具有显著的场强依赖特性;非线性电导涂层可以自适应调控直流GIL绝缘子的表面电荷与沿面电场分布,显著提高不同工况下的沿面闪络电压。该文的研究结果为高可靠性直流GIL绝缘子的研发提供了一种潜在的解决方案。     

覆冰绝缘子串泄漏电流与覆冰量及覆冰水电导率的关系

污秽与覆冰量是影响输电线路绝缘子冰闪电压的主要因素,因此有效预测污秽和覆冰量是防止发生冰闪事故的手段。本文通过人工气候室试验,模拟运行电压下覆冰量和覆冰水电导率对覆冰绝缘子泄漏电流的影响,提取了泄漏电流的三个特征量:泄漏电流脉冲幅值、谐波含量和电荷量,这三个特征量从不同角度描述了泄漏电流与覆冰量和覆冰水电导率的关系,并且得到了它们之间的回归方程式。基于泄漏电流特征量与覆冰量、覆冰水电导率的关系,提出覆冰绝缘子污冰预测神经网络模型,脉冲幅值、谐波含量和电荷量作为神经网络的输入量,污冰参数(ISP)作为神经网络的输出量。神经网络模型预测结果与试验测试结果对比分析可知,预测结果与试验结果的相对误差绝对值小于8.5%,因此本文提出的覆冰绝缘子污冰预测模型能够有效地对覆冰绝缘子ISP进行预测,为输电线路外绝缘的选择和设计提供参考依据,对于预防冰闪事故的发生有着重要的意义。     

反应合成AgSnO2电接触材料的组织与性能研究

采用反应合成技术和传统粉末冶金技术制备银氧化锡(AgSnO2)电接触材料。利用千瓦CO2激光器模仿电弧作用在试样表面产生局部熔化，对AgSnO2块体材料进行抗熔蚀性测试。对AgSnO：块体材料进行电导率测试和X射线衍射分析，对块体材料及冷拉拔的AgSnO2线材进行显微组织分析(扫描电镜、透射电镜)。研究结果表明，采用反应合成技术可以在银基体中合成尺寸细小、界面新鲜的SnO2颗粒，所制备的AgSnO2电接触材料中，微米级的SnO2颗粒系由纳米级的SnO2颗粒聚集而成I反应合成法制备的AgSnOz电接触材料较传统粉末冶金法制备的AgSnO2电接触材料具有更高的导电性和抗熔蚀性；该方法制备的AgSnO2电接触材料由于改变了Ag、SnO2的结合状态使材料的加工性能、导电性能和抗熔蚀性同时得到改善和提高。     

电子电气设备中塑料阻燃剂PBDE使用的危害性

多溴联苯醚(PBDE)广泛用作电子电气设备（EEE）产品中塑料件的阻燃剂,欧盟《WEEE指令》和《RoHS指令》的公布唤醒了世界各国对PBDE危害性的极大关注,本文在国内外多溴联苯醚(PBDE)危害性研究成果的基础上,介绍了电子电气设备(EEE)中多溴联苯醚(PBDE）使用的危害性。     

轨迹断面特征根对受扰轨迹最远点及动态鞍点的诠释

对于任何复杂模型,通过仿真得到特定扰动下的受扰轨迹后,就可沿轨迹将系统模型等值为分段定常的线性系统。轨迹断面特征根法采用的假设与欧拉积分法完全相同,即系统在且仅在单个仿真步长内被定常线性化。因此,在每个积分步内,不但可用静态扩展等面积准则(EEAC)法分析该轨迹断面上的能量稳定裕度(轨迹断面能量),也可用平衡点特征根技术分析该轨迹断面上的振荡阻尼与瞬时频率,而将断面处的不平衡功率与动能视为初始扰动。完整的受扰轨迹成为大、小扰动稳定分析的共同基础,断面特征根可反映复杂因素对振荡特性的影响,而EEAC可反映复杂因素影响同步稳定性的本质。引入"轨迹断面虚拟平衡点特征根序列"的概念,以计入断面处动能对滑步失稳的影响,并将滑步失稳与振荡失稳两者的机理相关联。据此考证最远点(FEP)和动态鞍点(DSP)处的振荡阻尼与瞬时频率,揭示大、小扰动失稳的内在联系。     

智能电器中的电磁兼容及其对策

基于对智能电器中的电磁兼容分析,提出了一些相应的对策.介绍了吸收回路、滤波电路、屏蔽技术、隔离技术和抗干扰设计等电磁兼容对策.这些技术手段可有效保护智能电器免受非线性负荷、雷击和浪涌的危害,提高电器可靠性.     

EIB现场总线技术在广场照明工程中的应用和设计

介绍了EIB现场总线技术和EIB系统运行软件设计和硬件要求,根据广场照明工程的特点,叙述了如何运用EIB现场总线技术,实现对广场照明的灵活控制.     

电场诱导蒙脱土在聚乙烯中取向分散及对其电树枝特性影响研究

为提高低密度聚乙烯(low-density polyethylene,LDPE)材料的抗电树枝老化能力,提出采用交流电场诱导蒙脱土(montmorillonite,MMT)片层,以实现其在低密度聚乙烯中取向分散的方法。首先,设计了电场诱导实验装置,用工频交流电场对熔融状态下的低密度聚乙烯/蒙脱土(LDPE/MMT)复合材料进行诱导实验;其次,通过测试材料的 X 射线衍射谱、紫外光透射率和材料断面、表面的扫描电子显微图片,表征了电场诱导对MMT在LDPE中的取向分散影响;最后,对比观察了电场诱导前后LDPE/MMT复合材料中的电树枝的引发和生长特性的差异。结果表明,电场诱导有助于MMT片层在LDPE中均匀分散,且使得MMT片层沿平行于电场的方向发生偏转,诱导后的 LDPE/MMT复合材料在垂直于取向电场的方向上具有更好地抑制电树枝的能力。     

化水系统EDI工艺与混床工艺的比较及应用

介绍了化水系统中的新型EDI工艺与传统混床工艺,着重分析两者间的相同性及差异性,比较其优劣及应用,从而验证EDI工艺在今后必将取代传统混床工艺,被广泛应用于电子、电力、生物、制药、化工等诸多领域。