Double injection model

Experimental results have been interpreted within the framework of a double structure model, which seems to capture the essential features of observed behaviour. The proposed model is capable also of making precise quantitative predictions. This has been shown by deriving model parameters from one of the tests performed (liquid injection) and by calculating the response of the vapour transfer test. 

In order to sustain the ON state by double injection or by tunneling it is necessary, as Lucas (1971) points out, that the carrier lifetime is longer than the transit time. Her model of switching is based on the idea that beyond a critical injection current both electron and hole traps are neutralized and as a consequence recombination is sharply decreased and the diffusion length becomes of the order of the film thickness. This sharply increases the bulk conductance and the sustaining field is again concentrated at the electrodes as in Figure 6.21(c). Lucas obtains for the critical current density at which the so-called recombination instability occurs... 

The mechanism of the excitation and emission can be explained by the electron injection model (2), in which the time constant of the luminescence decay is associated with the rate of forma tion of a charged double layer in front of the cathode, which is created and then stabilized by the applied potential. 

Injection port insert, cyclo-double gooseneck, Restek Magnetic stirrers, VWR, Model 200 Microsyringes, Hamilton Mill, Hobart Mill, Wiley... 

Actual responses of tuo carbonate petroleum reservoirs to matrix injection of hydrochloric acid are compared with a recently proposed experimental model for wormholing. This model is shown to be applicable in undamaged primary porosity reservoirs, and should be useable in damaged double porosity ones. Formations of no primary porosity are shown to respond very differently. 

FIGURE 4.8 Experiments and numerical modeling of sample introduction using the double cross-injection system during (a) loading steps and (b) dispensing steps. Reprinted with permission from the American Chemical Society [109]. 

In one study, PLG microspheres bound to DNA using a cryogenic double emulsion process and injected intramuscularly into mice were found to promote transgene expression for up to 174 days after injection, dependent upon microsphere mass. More recently nanoparticles were constructed from carboxy terminated, PEG modified PGL polymers. These particles were conjugated with an aptamer to the prostate specific membrane antigen and evaluated for in vivo biodistribution in an LNCaP (PSMA+) xenograft mouse model of prostate cancer. In this study, the aptamer caused a 3.77-fold increase in polymer concentration in the tumor tissue after retro-orbital injection (79). 

Sample purification and concentration used double-mechanism (cation exchange and reversed phase) solid phase extraction cartridges. The extracts from 5 mL of urine were dried, redissolved with 100 /aL of running buffer, and injected, to achieve a detection limit of 100 ng/mL. For peak identification, not only the retention times were used, but also the on-line-recorded UV spectra of the peaks, which were compared to computer-stored models. 

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