Control of Head Smear Generated From DLC Films Using an External Electric Field

In this study, the dependence of the electric field between the magnetic disk and Si wafer, used as the counter surface, on the hydrocarbon smear generated from the diamond-like carbon (DLC) overcoat was investigated. As a result, the positive electric field from the disk to the Si wafer increased the amount of smear, and the negative field reduced it. The positive electric field was estimated to extract hydrocarbon ions from the thermal plasma toward the Si wafer, and the opposite field attracts the hydrocarbon ions to the DLC surface. Therefore, the electric field between the slider and disk possibly controls the smear generation from the DLC overcoat, which is heated by laser irradiation in the heat-assisted magnetic recording).

SYNTHETIC APPROACH TO THE DEVELOPMENT OF TECHNOLOGY FOR MANUFACTURE OF COLD-DEFORMED REINFORCEMENTS IN ACCORDANCE WITH THE REQUIREMENTS OF TECHNICAL REGULATIONS AND MARKET

The article represents a synthetic approach to the development of technology for manufacture of cold-deformed reinforcement tailored to the needs of the market, which needs to have cold-worked reinforcement with negative field of tolerance on the linear density.

Cortical epileptogenesis of slowly kindled freely moving rats

Objective. Epilepsy is a neurological disorder that can be caused by many underlying pathologies. The epileptic and interictal manifestations that appear during the progression of chronic epilepsy are still not understood completely. One of the most frequent forms of this disease is temporal lobe epilepsy in which is clear involvement of the hippocampal formation. In order to study the electrografic progression of untreated seizures we used amygdala kindling in freely moving rats. Methods. Seven animals were implanted with bilateral hippocampal and prefrontal electrodes. A bipolar electrode, implanted in the lateral nuclei of the left amygdala was used for stimulation. The kindled group of animals was stimulated daily with the minimum current intensity needed to reach the afterdischarge threshold. Behavioral changes during kindling were scored according to the Racine scale. Results. The average seizure severity on the Racine scale was 2.6±0.4 by day 6 and 4.4±0.6 by day 20. The first spontaneous seizures appeared after 31 days of stimulation. During spontaneous seizures the preictal spike full width at half maximum increased gradually from 51±4msec to 110±5msec (p < 0.05) whereas the amplitude of the negative field potential deflection increased by 62% (p < 0.05). Conclusions. Our study showed that the progression of temporal lobe epilepsy, as seen in humans, can be reproduced in the kindling model with high fidelity. This study confirms in vivo the increase in preictal spike duration as well as the increase of the amplitude of negative field potential deflection during the preictal period.

Intersubband Transitions in Asymmetric Quantum Wells with External Electric Field

The quantum-confined Stark effect on the optical absorption of intersubband transitions in an asymmetric AlxGa1-xN/In0.3Ga0.7N/GaN quantum wells is investigated by means of the density matrix formulism. The built-in electric field generated by the piezoelectric and spontaneous polarizations competing against to the external electric fields is considered. As the result, the influences of the built-in and external electric fields on the energy potentials and the eigen stares are discussed in detail. When the positive external electric field is applied, the peak values of the absorption coefficients from 3-2, 2-1 and 3-1 transitions are reduced and moved to the lower photon energy levels. With the negative field, the exactly opposite results can be obtained. Moreover, it is indicated that the results of the wavelengths from the 3-2, 2-1 and 3-1 transitions are reduced by the positive external electric field and increased by the negative field.

Fine Structure Signatures in Ground Flashes as a Source for HF Radiation

Lighting radiation fields below 10 MHz are of considerable interest since these frequencies correspond to the natural resonance of structures with dimensions of a few meters to tens of meters. In this paper we present the fine structure signatures of sub-microsecond range pulses appeared at the leader phase and after the return stroke in negative ground flashes which act as a source for HF radiations at 10 MHz, 5 MHz and 3 MHz observed in Sri Lanka, in the tropics. Of the total sub-microsecond range pulses analyzed, 298 were due to positive field changes and 228 were due to negative field changes. The average rise time of those pulses for both polarities is 127 ns and it was found to be varying from 110-160 ns. The peak amplitude is in the range of 0.65-2.19 V/m. For the total 526 pulses analyzed for this study, the FWHM was between 190-310 ns with an arithmetic mean of 238 ns. Signatures of these pulses are similar to the leader like electric field pulses which acted as a strong source for HF radiations at 10 MHz, 5 MHz and 3 MHz. The initiation process of pulses reported in this study could be similar to the initiation process of leader like pulses.