Initial resistance

The conclusion regarding the fact that constant current conductivity involves not all microcrystals of the sample is proved by results of measurements of electric conductivity in sintered ZnO films in case of alternating current (Fig. 2.10). The availability of barrier-free ohmic pathways is proved by a low value of initial resistivity in sintered samples ( 1 - 5 kOhm) in addition to exponential dependence of electric conductivity plotted as a function of inverse temperature having activation energy 0.03 - 0.5 eV, which coincides with ionization energy of shallow dope levels. The same value is obtained from measurements of the temperature dependence of the Hall constant [46]. 

Batch filtration. Batch filtration involves the separation of suspended solids from a slurry of associated liquid. The required product could be either the solid particles or the liquid filtrate. In batch filtration, the filter medium presents an initial resistance to the fluid flow that will change as particles are deposited. The driving forces used in batch filtration are2 ... 

Fig. 2. Spreading resistance profiles from (a) Au-diffused n-type Si, (b) same sample after hydrogen plasma-exposure for lh at 200°C and (c) another position of the sample in (b). The bar represents the range of initial resistance values of the Si prior to Au diffusion (Mogro-Campero et al., 1985). 

Initial resistance caused due to air-gap is very high to allow conduction of current. Hence, the arc is first initiated by narrowing its gap momentarily while 110-220 V DC is applied. Once the current picks up flow, the temperature across the arc-gap shoots up promptly. The electrodes are pulled apart leaving a gap of 20 mm to 1 cm, thereby establishing the electric arc whose temperature varies from 4000 to 8000° K. 

Should the force be directed so as to deflect the path of the moving charge, an additional resistance, usually called the Hall resistance, would be observed. It should be noted that the magnitude of the effect is very small, invariably much less than 1% of the initial resistance. A secondary effect occurs in magnetic metals, however, and results in a modified magnetoresistivity curve. 

The account I heard most often in my interviews mirrors my own experience. It is one of ambivalence toward medications, of reluctance to rely on them, of movement from one drug or dose to another, and of uncertainty about the treatment s efficacy. It also hints at the process through which a clear majority of patients move—from initial resistance to a grudging acceptance of their need for medication. Eventually, those who follow this archetypal career capitulate to the idea that they will probably have to take medication for the rest of their lives. The first narrative, then, is one of partial success. We will hear it from Rachel, a twenty-nine-year-old accountant, whose depression was severe enough to have included a suicide attempt at age eighteen. 

While he initially resisted seeing a psychiatrist because he felt it was humiliating and didn t want anybody telling me there was anything wrong with my head, the depression and the desperation it created eventually pushed him into a doctor s office. When I asked Mike if he was also initially resistant to medications, he replied ... 

Sarah s history with nonprescription drugs was not shared by anyone else I interviewed, but her initial resistance to prescribed medications was very common. Also... 

Most of my interviewees who initially resisted taking medication were afraid of being labeled mentally ill. The following words express this common theme ... 

The loss of halogen in the irradiated areas, as expected, leads to a dramatic drop in conductivity. The TTF halide films have conductivities on the order of 10-20/ohm-cm. Irradiation causes the conductivity to drop by over 9 orders of magnitude. High conductivity of the initial resist films is a useful property since it prevents static charge build upon E-beam irradiation which can lead to concomitant loss of image resolution. 

Lavoisier s ideas met initial resistance from the established chemical community. After all, phlogiston had been used for a century to explain chemistry, and natural philosophers had explained their work based on phlogiston theory. The leading chemists of the day, including Richard Kirwan (1733-1812), Priestley, Cavendish, andTor-bern Bergman (1735-1784), not only rejected Lavoisier s ideas, but they also were antagonistic toward him. This was not to say... 

Figure 3. Typical lithographic response or contrast plots for (a) positive resists and (b) negative resists in terms of the developed thickness normalized to initial resist thickness (p) as a function of log (dose).

Peniche et al. (2004) successfully encapsulated up to 65 % of shark liver oil (rich in polyunsaturated fatty acids) in chitosan/alginate capsules in order to mask the oil s unpleasant taste. Here again it was found that the chitosan coating allowed a greater degree of control of capsule permeability. The capsules could be degraded by enzymes such as lipase or pancreatin. They were initially resistant to the acid environment of the stomach, although after 4 hours under intestinal conditions (pH = 7.4) the capsule walls were finally disrupted. 

Dickinson s method was used to obtain the corrected resistance change (3). This method involves the use of the equation R = R + 0.63 (ARobs) where R is the initial resistance before the reaction is initiated, and Rx is the resistance at tXy the time on a resistance-time plot where a vertical line drawn through this point will subtend equal areas to the left and to the right of the curve. 

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