Narrow Results

We report resistivity and thermopower of polycrystalline samples of Ni-doped LaRhO₃ from room temperature down to 4.2 K. The resistivity decreases with increasing Ni-doping, while the thermopower reaches almost a constant value (∼85 μV/K) at room temperature.

Single-walled carbon nanotubes (SWNTs), multiwalled carbon nanotubes (MWNTs) and vapor-grown carbon nanofibers (VGCNFs)/epoxy matrix nanocomposites were prepared, respectively. The microstructure of the nanocomposites was observed by SEM and the resistivities of the nanocomposites with different concentration of CNTs/VGCNFs were measured. Based on the experimental results, the dispersion of SWNTs and MWNTs were relatively poor but that of VGCNFs is uniform within the matrix. The resistivitiy of pure epoxy is about 10^10.5 Ω · cm and several orders of magnitude higher than those of SWNT, MWNT and VGCNF/epoxy nanocomposites. The resistivities of the nanocomposites drop with the increase of the CNTs/VGCNFs content in the matrix and the resistivity of VGCNFs/epoxy nanocomposites was much lower than that of CNT/epoxy nanocomposites.

This paper represents the behaviors of impressed current cathodic protection (ICCP) system in a reinforced concrete specimen using insoluble titanium mesh anode coated with mixed metal oxide (MMO). The ICCP system is increasingly used as a means of protecting corrosion for high resistivity conditions such as concrete or soil environment. Experiment was conducted by means of small laid column specimens such as ASTM G109 in order to confirm the performance of ICCP system using the MMO Ti-Mesh anode. The potentials and currents have been investigated and in addition, depolarization potential has been measured to reveal the effectiveness of ICCP. The minimum cathodic protection potential of atmospheric, fresh water, and 3 % salt water condition were 135 mV, 98 mV, and 93 mV. The CP current was much higher in seawater condition than freshwater and atmospheric condition. The potential drop caused by concrete resistance at atmospheric condition should be considered at depolarization potential measurement because of high resistivity of the concrete. The results show that the MMO Ti-Mesh anode was very effective anode in sea water condition as well as fresh water and atmospheric conditions

In this paper, titanium dioxide (TiO₂) was doped with the original formula of epoxy resin varnish to improve its abrasive resistance. The abrasive resistance test demonstrated that doping with 6% TiO₂ produced the highest abrasive resistance with a reduction of 30.23% in weight loss as compared to the original epoxy varnish. In addition, this same doping proportion reduced shore hardness by 21.91%, improved volume resistivity by 2 orders of magnitude and surface resistivity by 4 orders of magnitude as compared to the original epoxy varnish. Moreover, the adhesion of the epoxy resin was Grade 1.

Microstructure and properties in the tempering process of high temperature deformed Nb microalloyed Steels F40 had been studied by resistance heating and die casting machine. Results showed that in the process of resistance heating, temperature in central section of samples was higher than that in the edge. Fully austenitization was obtained when samples were heated to 1250°C. In the tempering process, the resistivity firstly decreased and then increased. Microhardness had the similar trend as resistivity except it decreased finally, which contributed to changes of microstructure and precipitated phases in the tempering process.

Highly resistive Al₂O₃ ceramics have been widely used for electrostatic chucking of silicon wafer. However, there are some restrictions to use such chuck material on higher resistance substrates, such as glass or sapphire wafer. In this study, Al₂O₃ compositions were modified by various dopants ; TiO₂, CuO and SiO₂, and their sinterability, crystal structure, electrical properties and chucking property were investigated with different doping concentrations and sintering conditions. Both of TiO₂ and CuO were found to be key dopants on controlling the sintering temperature and electrical resistivity. When 2~3 mol% of TiO₂ and CuO, and 1mol% of SiO₂ were added simultaneously, the specimens having lowered resistivity, ~10¹² Ωcm were obtained at a relatively lowered sintering temperature, 1250°C, which means that the electrostatic chuck for display and LED sapphire chip processes can be economically fabricated by using simple ceramic process.