Passivated linear devices

Imide passivated linear devices was determined from I-V characteristics of statistically significant numbers of devices following severe PTHB test (i.e., 15 psi, 120°C, 100% relative hvimidity, and 30 V bias). Two coat (3 p) polyimide passivation provided almost twice the mean time to failure of 1 p thick PSG passivation. Polyimide protection against high humidity (13,14) and Na" " diffusion (15) has been reported previously. 

As discussed in Section 2.2.1, propagation of a mechanical wave in a piezoelectric medium is accompanied by an associated wave potential, tj>. When the wave is incident on a receiving transducer, diis potential induces a current flow in each transducer electrode these currents combine to produce a current flow in the external detection circuit. The addition of current contributions in the receiving transducer is also optimized when the transducer periodicity matches the acoustic wavelength. Thus, a reciprocity relation holds, as it must for a passive linear device, between the wave and external signals. 

There are further errors because the value of B in equation (4.1) varies from 26 to 52 mV depending upon whether the steel is active or passive. Further, corrosion may be concentrated on the top of the bar, or, if bars are close together or deep within the concrete, the device may only send current to the top steel. Both of these errors mean that the best accuracy you can expect from a linear polarization device is a factor of 2 to 4 (Andrade et al., 1995). This is supported by the discussion in Section 4.12.4 which showed that seasonal fluctuations give a factor of 2.5 variation in LPR measurements. However, the scale is logarithmic so such errors are less critical than they seem to be. 

Reliability of electronic devices is caused predominantly by failures which result from the latent defects created during the manufacture processes or during the operating life of the devices. A search for new nondestructive methods to characterise quality and predict reliability of vast ensembles became a trend in the last four decades (Saveli etal. 1984), (Hartler et al. 1992), (Vandamme 1994), (Hashiguchi et al. 1998). The most promising methods to provide a non-destructive evaluation are an analysis of the electron transport parameters. Experiments are based on the measurements of device VA characteristics, nonlinearity using the non-linearity index (NLl), electronic noise spectroscopy, electro-ultrasonic spectroscopy and acoustic emission. These ones apply to both active and passive components, i.e., bipolar devices and MOS structures, on one hand, and resistors and capacitors on the other. 

An alternative method for the realization of KLM uses the birefringent properties of the Kerr medium, which turns the plane of polarization of the light wave passing through the Kerr medium. This is illustrated in Fig. 11.23. The incident wave passes through a linear polarizer and is then elliptically polarized by a A/4-plate. The Kerr medium causes a time dependent nonlinear polarization rotation. A A/2-plate and a linear polarizer behind the Ken-medium can be arranged in such a way that the pulse transmission reaches its maximum at the peak of the incident pulse, thus shortening the pulse width [11.55]. This device acts similarly to a passive saturable absorber and is particularly useful for fiber lasers with ultrashort pulses. 

The most diffused actuating configuration, in which these materials are used, is represented by the so-called unimorph bilayer bender. This kind of actuator consists of a film of active material coupled to a passive supporting layer. The bilayer structure is operated within an electrochemical cell, having a liquid electrolyte in which the device is immersed. The active polymeric layer of the actuator works as one electrode of the cell, while a counter electrode and a third reference electrode are separately immersed in the electrolyte. One end of the bilayer is constrained, while the other is free. The potential difference applied between the electrodes causes red-ox reactions of the conducting polymer. Since the CP and the passive layers are mechanically interlocked, when the polymer swells/shrinks the passive layer, which can not modify its dimensions, transforms the CP linear displacement into a bending movement of the structure [238-242]. Very similar is the bimorph structure. In this case the passive layer is substituted by a second CP film and they work in opposition of phase. 

The seismic response of structures subjected to earthquake excitations may be effectively reduced by incorporating any of various kinds of available passive energy dissipation devices (Soong and Dargush 1997). Niunerous are the studies related to optimal placement and capacity of damping coefficient for linear multistory buildings. 

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