A Study of the Effect of Sintering Conditions of Mg0.95Ni0.05Ti3 on Its Physical and Dielectric Properties

Mg0.95Ni0.05TiO3 ceramics were prepared by traditional solid-state route using sintering temperatures between 1300 and 1425 °C and holding time of 2–8 h. The sintered samples were characterized for their phase composition, micro-crystalline structure, unit–cell constant, and dielectric properties. A two-phase combination region was identified over the entire compositional range. The effect of sintering conditions was analyzed for various properties. Both permittivity (εr) and Q factor (Qf) were sensitive to sintering temperatures and holding times, and the optimum performance was found at 1350 °C withholding time of 4 h. The temperature coefficient of resonant frequency (τf) in a range from −45.2 to −52 (ppm/°C) and unit–cell constant were not sensitive to both the sintering temperature and holding time. An optimized Q factor of 192,000 (GHz) related with a permittivity (εr) of 17.35 and a temperature coefficient (τf) of −47 (ppm/°C) was realized for the specimen sintered at 1350 °C withholding time of 4 h. For applications of 5G communication device (filter, antennas, etc.), Mg0.95Ni0.05TiO3 is considered to be a suitable candidate for substrate materials.

Liquid Conductivity Sensor Based on AgPd Paste Fabricated on an Al2O3 Substrate Using Screen Printing Technique

In this paper, the design and fabrication of a liquid conductivity sensor based on AgPd paste will be described. The device was designed in a four-electrode configuration on a 10 x 25 mm2 96% Al2O3 substrate. The distance between the two driving electrodes was 4 mm, whereas the distance between the two measuring electrodes was 2 mm.The device was also integrated with a Ruthenium based temperature sensor printed on the backside of the substrate. Initial characterisation showed that the conductivity sensor has a measured sensitivity and cell constant of 1.67 cm and 0.51 cm-1, respectively, when a frequency of 1 kHz square wave input was appliedto the driving electrodes. Sensor’s respond variation against temperature was measured around 27.89 μS/°C, corresponding to 2.22 temperature compensation value for salt solution. The results showed a stable response over 5 days measurement cycle, indicating the sensor’s potential for field water quality monitoring application.

Geometric part of uncertainties in the calculation constant of the primary four electrode conductivity cell.

The paper presents the construction of a primary four electrode conductivity cell with calculated constant for the Ukrainian primary standard of electrolytic conductivity (EC). The equations for calculating the cell constant and the error budget for calculating uncertainty are presented. The components of the budget are: errors due to the non-uniformity of the force lines of the electric field; errors due to the accuracy of measurement standards and measuring instruments for determining length and diameter of the tube; and errors due to manufacturing techniques of tubes and their assemblage. The article considers in detail the errors due to the non-ideal profile of the central part of the tube. Two methods to reduce the standard deviation are given: the method of linear interpolation for compensation of the concave form which occurs along the axis of the tube and the method of equivalent triangles to compensate for deviations from a circle that occur across the axis of the tube.

Compositional effects and optical properties of CdSeXTe1−X alloyed nanotube arrays

The compositional effects on the cell constant, absorption and Raman scattering were demonstrated for well-aligned CdSeXTe1−X (0 ≤ X ≤ 1) nanotube arrays on ITO.