Conductive powder preparation and electrical properties of RuO2 thick film resistors

RuO₂ powders were prepared under different conditions to vary their properties. A study was made of the powder properties and electrical characteristics of thick film resistors (TFRs) containing an RuO₂ powder as a conducting component. Both crystalline size and specific surface area varied with calcination temperature but the change in the washing solution had different effects upon the two relationships. Variations in the total pore volume produce differences in the specific surface area at the same crystalline size. The resistivity of TFRs decreases and the temperature coefficient of resistance (TCR) becomes more positive with decreasing crystalline size. TFRs having conductive powder of higher specific surface area at the same crystalline size show lower resistivity and higher TCR values. This revised version was published online in July 2006 with corrections to the Cover Date.     

On the preparation,growth and properties of Cd3As2

A new general method for the preparation of compounds having volatile components, and its application to the preparation of Cd₃As₂, is described. The pulling of Cd₃As₂ by liquid encapsulation, using firstly a new encapsulant to clean the melt, and secondly a modified B₂O₃ encapsulant for pulling, is reported. Electrical properties of pulled Cd₃As₂ are given.The effects of annealing on the optical transmission of evaporated Cd₃As₂ films are described, and the energy gap suggested by optical transmission and photoconduction are briefly discussed.     

The preparation and electrical properties of NiSexS2−x pyrites

Crystals of the NiSe_xS_2?x pyrite solid solution series were prepared by chemical transport with Cl₂. With increasing temperature, resistivity increases sharply in compositions with 0.47 ≤ x ≤ 0.54. The transition temperature increases with x from 30K to 100K. Disagreement is found with recently reported polycrystalline data.     

制备工艺对PAR电双稳薄膜电特性的影响

采用真空蒸发的方法将有机电双稳材料PAR制成Al/PAR/Al夹层结构.详细研究了薄膜厚度、电极面积、退火处理和自然放置等因素对薄膜电性能的影响.结果表明,采用适当的工艺,能够获得性质均匀、电特性良好的电双稳薄膜(转变电压的分散性小于10%,延迟时间基本小于5μs,转变时间在20ns左右).Al/PAR/Al结构可以简单等效为电阻与电容的并联,而退火与自然放置将使薄膜结构趋于稳定.     

二维材料MXene的制备与电学性能研究进展

具有层状结构的二维过渡金属碳/氮化物材料(MXene)因其优良的导电性、良好的亲水性以及丰富的表面化学结构得到了大部分研究者的关注.着眼于MXene的先进制备方法及过程展开综述,同时综述了其在电学方面(包括超级电容器,电池材料和电催化)的研究进展.在MXene超级电容器中相较于普通水系电解液,有机电解液或离子电解液往往...     

On the optical and electrical properties of the Zn3In2S6 layered compound

The electrical properties of the layered compound Zn₃In₂S₆, which is the third member of the system mZnS  In₂S₃ (m =3), were studied. The results obtained from the conductivity measurements indicate that a shallow electron trap at E_x = E_c − 0.54 eV with a concentration of about 10¹¹ cm⁻³ is responsible for its electrical behavior. Optical absorption results at various temperatures indicate a direct energy gap. Its relatively high value at room temperature E_g = 2,77 eV is attributed to the specific structure of this compound. A stability of the values of the temperature coefficients in the mZnS  In₂S₃ compounds is also observed.     

On the structural and electrical properties of modified PbTiO3 ceramics

Ceramics (Pb_0·75Ca_0·25)[(Ni_1/2W_1/2) _y Ti_1−y ]O₃ fory = 0 ·05, 0·10, 0·15 and 0·30 have been prepared using high temperature solid state reaction method. X-ray analyses show that these materials are of single-phase perovskite type tetragonal structure. To solve inaccuracy in finding para-ferroelectric phase transition temperatureT _c(ε _max), we have carried out the analyses of the data using a computer program. The role of Ni and W as modifiers on structural and electrical (dielectric and pyroelectric) properties is discussed in terms of the usefulness of these materials. Results indicate that ceramic Pb_0·75Ca_0·25Ni_0·25W_0·025Ti_0·95O₃ is a good candidate for pyroelectric applications. Paper presented at the poster session of MRSI AGM VI, Kharagpur, 1995     

On activated sintering and electrical properties of NaKNbO3

Sintering of Na_0.5K_0.5NbO₃ may be activated by slight excess of Nb⁵⁺ ions or by incorporation of Mg²⁺ ions into crystal lattice. By this means, high density samples (97% TD) were prepared by conventional sintering technique. Mg-doped sintered samples exhibit increase in k_p, some lowering in ε and large increase in resistivity after prolonged sintering.     

Frequency-dependent electrical properties in the system SnO2-TiO2

The a.c. impedance response of polycrystalline ceramics Sn_xTi_-x1O₂ was studied in the air in the temperature range 298–1073 K. The impedance spectra were analyzed in terms of two proposed equivalent circuits involving both resistor and non-Debye constant phase element (CPE). The presence of CPE elements may be interpreted by diffusion phenomena. The results indicate a negligible contribution of grain boundary resistance to the total resistivity of the studied materials. The determined activation energy of the bulk conductivity of TiO₂ was compared with literature data. © 2001 Kluwer Academic Publishers     

On the calculation of the electrical properties of precision coaxial lines

Practical examples of air lines are slightly inhomogeneous. We give an approach for the calculation of such an air line being exclusively based on a) geometrical parameters and b) material parameters. We show that-within the limits of actual deviations of high-precision air lines-the impact of the diameter variation is by far stronger than an excentrically placed inner conductor or a deformed cross section. We find that, from a practical point of view, the conductivity of the air line conductors is the most sensitive parameter. The resulting electrical behavior of the real air line is slightly reflective, i.e., it may no longer be described by a scalar transmission factor. A simple formula for its equivalent electrical length and some test relations for the validity of this formula are given.     

电工钢片磁性的计量问题

综述了电工钢片计量的当前水平和最新进展,重点讨论了在交变场中的标准测试方法:Epstein方圈法和单片(SST)法.所讨论的相关条款是有关磁通密度控制、数据获取和数据计算的最新电子方法,以及磁路设计对这两种方法的准确性和精度特性的影响,也讨论了系统误差来源、再现特性和经济因素等.     

In situ preparation, morphology and electrical properties of carbon nanofiber/polydimethylsiloxane nanocomposites

For the first time, a series of carbon nanofiber (CNF)/polydimethylsiloxane(PDMS)-based nanocomposites was prepared using in situ polymerization technique by critical manipulation of factors, such as method of preparation and chemical modification of filler. Quantification of the degree of dispersion was done by introducing a dispersion degree parameter. Extent of dispersion was found to improve by amine modification of CNFs. Electrical conductivity was found to undergo profound increase when compared with that of the insulating base polymer. Amine-modified CNF-based nanocomposites showed percolation threshold at lower filler loading compared with unmodified CNF-based nanocomposites. These results of electrical properties measurements were correlated with the results of TEM analysis.     

Antimony-incorporated TiO2 thin films: preparation and optical and electrical characteristics

Antimony-incorporated TiO₂ thin films were prepared using the spray-pyrolysis technique. The optical characteristics (percentage transmittance, refractive index, extinction coefficient) and the film thickness were investigated. The resistivity of the prepared samples was measured, and the effect of Sb concentration and film thickness on the measured parameters was discussed. The effect of Sb on the band-gap was also studied.     

纳米二氧化钛光触媒透明乳液的制备及性能研究

以四氯化钛、氨水和无机络合剂等简单易得的试剂为主要原料，采用低温络合．控制水解法，制备出了纳米二氧化钛透明乳液。室温下对乳液进行干燥后，采用XRD、TEM对所得粉末样品的物相、形貌进行了表征。在太阳光照射下，利用该透明乳液对酸性红染料进行了降解实验，同时研究了样品加入量、体系pH值、酸性大红3R浓度对降解效果的影响。制备的样品性能优于白色纳米TiO2乳液，是一种性能优异的光催化材料。     

The electrical properties of Fe2WO6

Fe₂WO₆ was found to be a p-type semiconductor with an energy gap of 1.68 eV. The drift mobility ( _d) and mean free path (L) of the charge carriers have been calculated by combining the electrical conductivity and thermoelectric power data. It is proposed, from the magnitude ofL and _d and the temperature dependence of _d, that the charge carriers in Fe₂WO₆ are small polarons and that the charge transport process occurs by a hopping mechanism below 800 K. Above 800 K the results are explained using a narrow d-band model. The dielectric constant as a function of temperature exhibits two stages of increase: (i) a slow rise at lower temperature which is attributed mainly to an increase in ionic polarization and (ii) a fast rise at higher temperature which is ascribed to space charge polarization.     

The preparation of cadmium phosphate and cadmium zinc phosphate glasses and their electrical and optical properties

The preparation of a range of glasses based on CdO-P₂O₅ and CdO-ZnO-P₂O₅ is described and data are reported on density, electrical conductivity and optical absorption. The electrical conduction is electronic rather than ionic and is due to hopping between localized states. The optical absorption is due to forbidden indirect electronic transitions.     

Preparation and electrical properties of SrBi2Ta2O9 ceramic

SrBi₂Ta₂O₉ (SBT) ceramic materials were prepared by the conventional mixed-oxide method. Ceramics sintered at different temperatures had distinctly different microstructures. Anisometric plate-like crystalline grains were observed which revealed the layered structure of the material. The variations of the saturation polarization (P_s), remanent polarization (P_r) and coercive field (E_c) with applied field and temperature were studied by hysteresis (P-E) loop measurements. Samples were also DC poled at various temperatures and electric fields, and their permittivity, piezoelectric (d₃₃) and pyroelectric coefficient (p) were measured.     

Correlation between the structural and electrical transport properties of SnO2 films

Transparent and conducting thin films of tin oxide have been deposited by spray pyrolysis on Corning 7059 substrates. The films were investigated by X-ray diffraction and Seebeck measurements to study the structural and electrical transport properties. The films were polycrystalline and the oxide phase observed was SnO₂ in cassiterite structure. The films were preferentially oriented along [200]. Trap densities along [310] and [101] have been calculated for the first time. Assigning the traps mainly to the grain boundaries, the grain-boundary barrier height was calculated and compared with that obtained from the Seebeck measurements. A good agreement between these values was observed. The agreement was the best for films deposited under optimum deposition conditions.     

Microstructure and electrical properties of MgO-doped SnO2 varistor ceramics

The effect of MgO addition on the properties of (Co, Nb, Cr)-doped SnO₂ varistors was investigated. The samples with different MgO concentrations were fabricated by the conventional ceramic method and sintered at 1,250, 1,300, 1,350 and 1,400 °C for 2 h. It was found that the nonlinear coefficient presented a peak value of 28 and lowest leakage current density of 7 μA/cm² when 0.5 mol% MgO was added. The breakdown electrical field increased from 174 to 531 V/mm with increasing MgO from 0.0 to 2.0 mol%. The relative dielectric constant decreased with increasing MgO from 0.0 to 0.5 mol%, but increased with more MgO added. The dielectric loss decreased obviously in the case of low frequency with MgO added, and it had the lowest value when 0.5 mol% MgO added. The optimal samples were obtained by doping MgO with 0.5 mol% and sintering at 1,350 °C.