溶胶-凝胶法低温自燃合成BaCe_(0.9)Nd_(0.1)O_(3-δ)粉体

采用低温燃烧合成工艺合成了BaCe0.9Nd0.1O3-δ固体电解质。研究发现,初始溶液中柠檬酸和硝酸铵的比率对自燃反应的燃烧焓以及凝胶的分解温度有着重要影响。利用TG-DSC,XRD,TEM和BET对制备的粉体表征。实验结果表明,在800℃得到的粉体平均粒径为40～50nm左右。在900℃基本形成钙钛矿相,比传统固相反应法要低700℃以上。     

Fabrication of YBCO Coated Conductors on Biaxial Textured Metal Substrate by All-Sputtering

CeO2/YSZ/CeO2 buffer layers were prepared on biaxial textured Ni-5at.%W substrate by direct-current magnetron reactive sputtering with the optimum process. YBCO thin films were deposited on CeO2/YSZ/CeO2 buffered Ni-5at.%W substrate at temperature ranging from 500℃ to 700℃ by diode de sputtering. By optimizing substrate temperature, pure c-axis oriented YBCO films were obtained. The mierostruetures of CeO2/YSZ/CeO2 buffer layers were characterized by X-ray diffraction. A smooth, dense and crack-free surface morphology was observed with scanning electron microscopy. The critical current density Jc about 0.75 MA/cm2 at 77 K was obtained.     

Conductivity pre-exponential factors for some new superionic conductors

The pre-exponential factors obtained from the ionic conductivity studies on Na₂(La, Al)ZrP₃O₁₂, Na₂(La, Al)TiP₃O₁₂, NH₄Zr₂V₃O₁₂ and AlPO₄:Li⁺ have been analysed. The compensation law has been found to be valid for these materials indicating that the entropy is directly related to the activation energy. The 1/α vsβ plots show straight lines for most of the superionic materials except for a few and this variation has been discussed.     

三峡工程用架空导线研制与生产及对线缆行业技术进步的推动

通过对三峡输电工程用大截面及特种架空导线组织研制工作的介绍 ,总结了攻关研制工作取得的技术进步和对三峡输电工程建设的积极配合作用 ,简述了以科研工作为先导 ,以国家重大工程为依托 ,开展行业技术创新工作的体会 ,这也是对行业技术创新工作如何密切配合工程、如何为工程服务 ,紧密依托行业 ,发挥整体作用的新尝试     

Estimation of the temperature rise in cylindrical conductors subjected to heavy 10/350 μs lightning current impulses

Lightning is a very high-energy phenomenon, which can pose serious dangers for human beings and the environment. Although much progress has been made in the area of lightning protection, there are still many cases of fires caused by lightning and power and telecommunication system outages. We have carried out an experimental and mathematical investigation into the temperature rise in cylindrical conductors subjected to heavy 10/350 μs lightning current impulses. The temperature rise measurements took place in one of the most reliable laboratories in Europe (BET, Menden, in Germany). The proposed mathematical models used to estimate the temperature rise in cylindrical conductors assumed both a uniform and non-uniform current density distribution by taking into account the transient skin effect. In addition, verification of the mathematical results were studied. Suggestions for further investigations are also provided. The experimental results are consistent with the results from the mathematical models. It is convincingly shown that copper conductors can be influenced by the transient skin effect. The additional temperature rise however, caused by the transient skin effect, is minimal, and can be neglected.     

湛江东海10 kV架空绝缘导线雷击断线分析与防护

通过对湛江东海地区10 kV架空绝缘导线的调研,分析了架空绝缘导线雷击断线机理,阐述了绝缘导线断线理论计算方法,针对雷击断线问题,介绍国内外常用的5种防护措施及安装范围的说明,并结合东海地区配电线路的具体情况,提出了在架空绝缘线路上安装穿刺型防弧金具或过电压保护器,能够降低雷击断线事故,并且比较经济、有效、可靠.     

基于内点法参数辨识的架空导线径向热路模型

为克服架空导线径向热参数难以理论计算的问题,基于径向导热时间常数及导线载流温升变化率两类热路参数,建立了状态方程形式的导线径向热路模型.利用模型响应构造了热路参数辨识的非线性目标函数,通过内点法求得参数辨识最优解.根据辨识结果建立了模型参数与载流量函数关系的拟合多项式.设计了架空导线径向温升实验平台,在自然对流条件下对LGJ-400导线温升过程进行了实测.研究结果表明:架空导线径向温差及各层导线载流温升变化率均随载流量的提高呈增大趋势,径向导热时间常数变化不呈明显单调性规律;所提模型的最大平均相对误差为2.12％,IEEE标准计算模型最大平均相对误差高达9.19％.故径向热路模型具有更高计算精度,可用于估计自然对流条件下的导线径向温度分布.