Electrical Conduction in β-Bi2O3 Doped with Sb2O3

Electrical conduction in tetragonal β-Bi₂O₃ doped with Sb₂O₃ was investigated by measuring electrical conductivity, ionic transference number, and Seebeck coefficient. The β-Bi₂O₃ doped with 1 to 10 mol% Sb₂O₃ was stable up to 600°C and showed an oxygen ionic and electronic mixed conduction, where the electron conduction was predominant at low oxygen pressures. The oxygen-ion conductivity showed a maximum at 4 mol% Sb₂O₃, whereas the activation energy for the ionic conduction remained unchanged for 4 to 10 mol% Sb₂O₃-doped specimens. These results were interpreted in terms of the oxygen vacancy concentration and the distortion of the tetragonal structure. The electron conductivity and its oxygen pressure dependence decreased with increasing Sb₂O₃ content. The fact that Sb⁵⁺ is partially reduced by excess electrons in heavily doped β specimens at low oxygen pressures is explained.     

Electrical Conduction in Co1-χMgχO

Electrical conductivity and thermoelectric power were measured on Co_1-χMg_χO (0.16χ 0.87) at 900° to 1200°C. Electrical conductivity σ decreased and the activation energy increased with increasing MgO content. Seebeck coefficient α appeared to be positive for all χ. The difference in temperature dependence of σ and α was 0.2 to 0.5 eV and the hole mobility decreased with increasing MgO content. The results were interpreted as showing that electron holes were localized to cation clusters and their thermally activated hopping conduction was operative in the solid solution. The dominant lattice defect changed from singly to doubly ionized cobalt vacancy with increasing MgO content.     

Gas Sensing Characteristics of Porous ZnO and Pt/ZnO Ceramics

Changes in resistivity and chemical changes in reducing gases were measured for porous zinc oxide ceramics with and without a platinum catalyst at 300° and 400°C to examine the gas sensing mechanism and the effect of platinum additions. Reducing gases were oxidized to CO₂ and Hz₂ on the sensor surfaces. Platinum addition promoted the oxidation of reducing gases but did not lead to an increase in the resistivity change at 400°C. The reaction sequences for the gas sensing process are proposed, taking into account partially oxidized intermediates of hydrocarbons and oxidation on platinum without an electron transfer process.     

低能离子束辅照对溅射镀TiN膜生长的影响

用诱导型等离子体辅助磁控溅射装置在Si（100）表面低温沉积TiN膜，研究了高密度低能量（≈20eV）离子束辅照对溅射镀TiN膜生长、结构和性能的影响．结果表明，高密度低能离子束辅照会改变TiN膜的择优生长方向并使薄膜致密化。即使沉积温度低于150℃，当入射基板离子数和Ti原子数的比值Ji／JTi≥4.7时，沉积的TiN膜仍可具有完全的（200）面择优生长，薄膜微观结构致密，硬度达到25GPa，残余压应力小．     

The Influence Analysis that a Phase Characteristic of the High‐Level Earthquake Gives to Vibration Response Characteristic of the 550‐kV Disconnectors

We developed the 550‐kV disconnectors that strengthened earthquake proofing by the addition of the damper unit and weight reduction of conductive part based on the damage of the 550‐kV disconnectors by the Great East Japan earthquake (March 11, 2011) and inspected the earthquake proofing performance by shake table test. In shake table test, we performed the test by the artificial seismic wave that varied in phase characteristic in addition to the test by resonance method. And, in a high‐level earthquake area, we analyzed it about the influence that a phase characteristic of the artificial seismic wave gave to stress to occur in disconnectors. As a result, it is thought that the stress to occur in disconnectors is decided by a primary natural frequency basically because a bending strain to occur to the disconnectors in the time when the resonance frequency ingredient becomes the big acceleration response value grows big. But, on a particular phase condition, it was confirmed that the bending strain to occur in disconnectors might grow big conspicuously. As for this, the possibility is thought about by influence of higher natural frequency doing superposition.     

Winding Method to Reduce Vibration and Loss Caused by Fractional Slot of Synchronous Machine

Fractional‐slot windings are widely used in rotating machines in order to improve the output voltage waveform, increase the design flexibility, and gain many other advantages. However, fractional‐slot windings are known to produce different harmonic components such as an even order and/or fractional number of space flux harmonics compared to integral‐slot windings. These harmonics may increase stray losses and cause stator core vibration. This paper describes an analysis of space flux harmonics and proposes new winding methods such as “novel interspersed windings” to reduce these harmonic components. The proposed winding methods were verified by numerical analysis and model tests.     

BIDIRECTIONAL TRANSMISSION OF ADDRESSED AUDIO SIGNAL THROUGH GI MULTIMODE OPTICAL FIBRES

This paper describes two types of bidirectional addressed audio signal transmission systems where the square-wave frequency modulation (SWFM) and intensity modulation (IM) are used to obtain the optical SWFM signals generated from LEDs at 850 nm. The first one is an addressed audio signal transmission network of tree structure. The sender and auxiliary receiver in the centre are connected to four terminals, each consisting of a receiver and an auxiliary sender, through pairs of optical fibres and an optical splitter used as an optical signal distributor. The second one is a new type of full-duplex one-to-one communication system. The sender and auxiliary receiver in one terminal are connected to the receiver and auxiliary sender in the other terminal through an optical fibre and a pair of directional couplers. Although LEDs in the second system deliver optical SWFM signals at the same wavelength of 850 nm at the same time, the communications are satisfactory because there is no interference from one LED to the other. In both the first and second experimental systems, the audio signal, address, and SWFM carrier occupy 10 Hz to 20 kHz, 65 kHz to 710 kHz, and 6 MHz, respectively. The SNR and distortion were 62 dB and 0.4 per cent, respectively.     

铁液处理状态对初生奥氏体形核的作用机制

对Fe-C亚共晶合金熔液在1723K保温1h,进行熔融玻璃净化处理,并在净化过的铁液中添加灰铸铁、白口铁和电解铁试块,探讨铁液净化和碳元素加入方式对初生奥氏体形核过冷度、形核数量和生长方式的影响。结果表明,铁液经玻璃处理后,初晶与共晶形核困难。当在净化过的铁液中添加灰铸铁后,初晶和共晶均易于形核。不同处理状态分别起着消除或生成“Fe的富集区”的作用,时初生奥氏体的非自发形核有着显著的影响。     

添加钛、铌、锰、硫及镁对亚共晶灰铸铁初生奥氏体形核及生长的影响

共晶铸铁在共晶凝固时,熔体中碳的状态,即“C的微小集合体”已经被深入研究.然而时于与初生奥氏体密切相关的铁原子的状态,即“铁的微小集合体”却缺乏研究.本文作者提出,在亚共晶灰铸铁熔体中,初晶γ的形核受“Fe的富集部”的影响,而“Fe的富集部”的形成及消失与“C的微小集合体”有关.研究表明,初生奥氏体的形核过冷度、形核数和晶核生长形貌随工艺条件如过热度、保温时间和冷却速率而变化.本文讨论了在熔体的过热度、保温时间和冷却速率固定的条件下,钛、铌、锰、硫和镁这五种添加元素对亚共晶灰铸铁初晶γ的凝固过程的影响.     

Dependence of Grain-Boundary Resistivity on Grain-Boundary Density in Yttria-Stabilized Zirconia

The dependence of grain-boundary resistivity and resistance per square centimeter of grain-boundary surface on grain-boundary density (D) in yttria-stabilized zirconia was investigated using reported data. The grain-boundary resistivity increased with increasing D in the high-D region but was independent of D in the low-D region. These results were interpreted in terms of intrinsic effects such as lattice irregularity and extrinsic effects such as impurity segregation.