Materials Literature
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The surface charge decay and space charge distribution in corona-charged low-density polyethylene (LDPE) were investigated. The space charge distribution was measured at 30/spl deg/C with the pulsed electro-acoustic (PEA) method, where a corona charged specimen was set between a semiconductive electrode and an Al elec…
Partial discharge(PD) tests were used to evaluate the insulation condition of seven large motors. These tests were conducted using a conventional partial discharge detector (PDD), turbine generator analyzer (TGA) and partial discharge analyzer (PDA). Off-line PD measurements were performed using the PDD. Offline PD pu…
Hydrophobicity of polymeric insulating material surface such as silicone rubber insulator was studied by using image data analysis of the sample surface. Hydrophobicity of polymer was evaluated by the motion of water droplets on the sample surface under AC high field application. The vibration image of the water dropl…
The electric field and voltage distributions along wet polymer insulators are calculated using COULOMB, a three-dimensional electric field analysis software package. These distributions are distorted by the presence of water droplets on the surface of the insulators. The cases analyzed are based on several stages of t…
There are various methods for determining the reaction parameters using thermal analysis data. In recent years, genetic algorithms have been considered as a new method for the determination of kinetic parameters. In the present study, calcination kinetics of ulexite was investigated by thermogravimetry (TG) using the…
Scattering losses for fused silica were measured over a wide wavelength range (193-800 nm) using different laser sources. The data indicate that scattering centers are smaller than ~ 12 nm, and scattering is consistent with Rayleigh type even at 193 nm. Scattering losses scale with wavelength as 1/λ<sup>4</sup>,…
Experimental investigation into the behaviour of partial discharges (PD) in different types of defect models are described in this paper. The models were used to study the waveshape and frequency spectra of the signals resulting from discharges. This information is then used to investigate the effect on the signals of…
Gaseous voids in polymeric dielectric materials are likely locations for partial discharges (PD). Numerous parameters influence the development of the charge avalanche. To date, various experiments and simulations have been carried out to investigate the PD behaviour as a function of the geometry of disc-shaped or sph…
The performance and reliability of electronic devices composed of multiple thin layers of material are highly dependent on effective thermal management. Since the thermal properties of thin films, such as SiO/sub 2/, can vary considerably from bulk values, the determination of those properties is critical for the purp…
The present work is part of a research program aimed at studying the long-term performance of electric motor insulation systems which are part of modern drives (equipped with fast inverters/converters). In particular the degradation effects of partial discharges (PD) were here experimentally studied. Different (purpos…
This paper describes the integration of a silicon carbon nitride (SiCN) copper passivation and etch stop layer into a Cu low k dielectric interconnect technology. The incorporation of SiCN improves interconnect performance by virtue of its lower dielectric constant as compared to silicon nitride, and through changes t…
It has been known that the electrical breakdown of insulating materials is strongly affected by the formation of space charge in the bulk of materials. Many researchers have attempted to study the relationship between the space charge and the breakdown, however, it has not been clear yet. Although the pulsed electroac…
Inference of apparent mobility of charge carriers in polymeric materials by means of space charge measurements performed during depolarization is presented in this paper. New expressions are proposed here, which are alternative to those already developed in a previous work, both applicable to space charge quantities m…
Chemical defects and impurities are thought to be responsible for the deep trapping of charge carriers in polymeric insulating materials such as peroxide crosslinked polyethylene (XLPE). Such excess charges, referred to as space charges, might cause localised high electric stress, possibly leading to dielectric breakd…
Electromigration in 0.23 /spl mu/m wide Cu dual-damascene lines connected to W underlayers has been investigated. Void growth at the vicinity of the cathode end of the line/via was determined to be the cause of the line failure. The distribution of failure lifetimes was found to be closely represented by a two-log-nor…
Methods for estimation of variance for the three-dimensional (3D) reconstruction from projections are introduced. First, a Fourier space variance for a class of 3D reconstruction algorithms that involve interpolation is derived. It is used to construct a test for the validity of the single particle analysis process. S…
The authors have been probing the possibility of applying functionally graded materials to solid insulators in order to control the electric field profiles, and resultant improvement of insulation level. Investigated in the paper are the effects of the capacitive bulk-grading of the coaxial disc-type and post-type mod…
The measurement of partial discharge (PD) activity is used for monitoring the insulation condition. In particular, it is of importance to obtain an indication of the time to breakdown for high voltage distribution power cables, both for cable factories and for the utilities. In this paper the authors investigate the u…
Random wound stator windings in motors, operating in utility and industrial plants, have been reported to suffer from premature failures. Although several failure mechanisms exist, dissection of failed stators show some of these failures have been caused by exposure to fast rise-time voltage surges coming from inverte…
Relativistic density functional theory (DFT) calculations of transition metal hyperfine interaction ( A ) tensors have been completed for a series of Cu 2+ complexes including Cu(Quin) 2, Cu(Acac) 2, Cu( l -AlaO) 2, and [Cu(Ox) 2 ] 2- . The A tensors were calculated with the zero order regular approximation (ZORA) for…