Using thermally stimulated currents to find defective capacitors

BaTiO₃ multilayer capacitors with a nominal capacitance of 3.5nF have been carefully measured using the thermally stimulated current (TSC) technique. When a 300V polarization voltage is applied at room temperature, a new TSC peak appeared in defective sample A after it has been immersed in water. No new peak was found in good-quality sample B after a similar treatment. The accelerated life test shows that sample A hasa much shorter life than sample B in terms of insulation resistance.     

TEM method for rapid and precise evaluation of continuous recrystallization

With the aid of a double-tilt holder in a transmission electron microscope, a new method for a rapid and precise determination of the misorientations of a large number of subgrain or grain boundaries is given in this article. By use of the method, the continuous recrystallization can be rapidly and precisely evaluated when compared to the other conventional methods.     

Pull-out and fragmentation in model fibre composites

An experimental study has been carried out of debonding and fibre rupture in model composites. A single glass rod or fibre was embedded in the centre of a long transparent silicone rubber block. Strains in the rubber in close proximity to the rod or fibre were measured as the specimen was slowly stretched. Pull-out forces, strain distributions, and debonded lengths are compared with the predictions of a simple theory based on a fracture energy criterion for debonding, and taking into account friction at the debonded interface. Experiments were carried out with rods of different diameter, rubber blocks of varied cross-section, and with two levels of adhesion. By extrapolating the debonded length to zero, values of the debonding force in the absence of friction were obtained. They were in accord with fracture energies of about 50 J/m² for weak bonding and about 200 J/m² for strong bonding. Fibre fragmentation lengths were measured also. They were in reasonable agreement with the inferred fracture energies and the measured frictional properties of silicone rubber sliding on glass. In a separate study, it was found that the frictional stress between cast silicone rubber and glass was approximately constant, about 0.1 MPa, rather than proportional to pressure, for pressures exceeding about 0.02 MPa. This feature is attributed to a particularly smooth interface between the two materials.     

Extremum-seeking with variable gain control for intensifying biogas production in anaerobic fermentation.

A state-dependent variable-gain control system is implemented to follow the characteristics of a laboratory-scale up-flow anaerobic fixed-bed reactor dynamically. The transition from one state to another is determined on an hourly basis, depending on difference between the setpoint of the reactor pH and its true value. Considerable improvement of the process stability--reduction of oscillation in both the reactor pH and biogas production rate during high-rate operation, has been achieved, although the control structure is simple and intuitive.     

The origination and optimization of Si/SiO/sub 2/ interface roughness and its effect on CMOS performance

As CMOS device dimensions scale down to 100 nm and beyond, the interface roughness between Si and SiO/sub 2/ has become critical to device performance and reliability. Si/SiO/sub 2/ interface roughness degrades channel mobility decreasing drive currents. The authors have used atomic force microscopy to study surface roughness in the processing of 0.16 /spl mu/m CMOS integrated circuits. All of the process steps that could potentially affect the interface roughness have been studied. The results show that oxidation is the major contributor to the interface roughness. The rms roughness is found to be linearly dependent on oxide thickness. Transistors with Si/SiO/sub 2/ interface rms roughness that has been reduced from 1.6 to 1.1 /spl Aring/ by reducing oxide thicknesses show improved device drive currents. This technique for interfacial smoothing and device performance improvement has the advantage of being easily implemented in today's technology.     

Efficient particle filter-based processing algorithm for clutter suppression and IR point targets enhancement

A novel soft decision-based median subtraction filter is presented for clutter suppression and infrared (IR) point targets enhancement. The decision is made based on a jump Markov model and its state and parameter estimation using a particle filter. The scheme is compared with other conventional clutter background removal techniques and good results are obtained.