Drift-Diffusion

2 Drift-Diffusion If every step takes time 8t, then 

The above equation can be obtained more directly from Equation 6.10, 

In view oip + q= 1, this gives the same equation as Equation 6.25, 

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DRIFTS Diffuse reflectance infrared Fourier-transform Same as IR Same as IR... 

Diffuse reflection iavolves reflecting the iafrared beam off of a soHd sample, as ia specular reflectioa, but it is the aoaspecular portioa of the reflected radiatioa that is coUected. Whea an ftir spectrometer is used, diffuse reflection is caUed DRIFTS (diffuse reflectance iafrared Fourier-transform... 

The device model describes transport in the organic device by the time-dependent continuity equation, with a drift-diffusion form for the current density, coupled to Poisson s equation. To be specific, consider single-carrier structures with holes as the dominant carrier type. In this case,... 

In the fluid model the momentum balance is replaced by the drift-diffusion approximation, where the particle flux F consists of a diffusion term (caused by density gradients) and a drift term (caused by the electric field ) ... 

In order to be able to explain the observed results plasma modeling was applied. A one-dimensional fluid model was used, which solves the particle balances for both the charged and neutral species, using the drift-diffusion approximation for the particle fluxes, the Poisson equation for the electric field, and the energy balance for the electrons [191] (see also Section 1.4.1). 

DRIFTS Diffuse reflectance infrared detector (see HECD)... 

Although acetone was a major product, it was not observed by infrared spectroscopy. Flowing helium/acetone over the catalyst at room temperature gave a prominent carbonyl band at 1723 cm 1 (not show here). In this study, a DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) cell was placed in front of a fixed reactor DRIFTS only monitored the adsorbed and gaseous species in the front end of the catalyst bed. The absence of acetone s carbonyl IR band in Figure 3 and its presence in the reactor effluent suggest the following possibilities (i) acetone formation from partial oxidation is slower than epoxidation to form PO and/or (ii) acetone is produced from a secondary reaction of PO. 

The third term describes the polarization set up by ultrafast drift-diffusion currents, which can excite coherent phonons via TDFS (or via the buildup of electric Dember fields [9,10]). The first two terms represent the second- and the third-order nonlinear susceptibilities, respectively [31]. The fourth term describes the polarization associated with coherent electronic wavefunctions, which becomes important in semiconductor heterostructures. 

DRIFT diffuse reflectance infrared Fourier transform... 

Neurotransmitter/Receptor Binding. At this point, the neurotransmitter chemical is free in the synapse (extracellular fluid) and drifts (diffuses) in all directions. Some of the neurotransmitter molecules float across the synapse and bind to receptors on the surface of the adjacent nerve cell. Each neurotransmitter has its own unique three-dimensional shape and binds with certain receptors but not others. The binding between a neurotransmitter and a receptor is similar to fitting a key into a lock. When the neurotransmitter binds the receptor, the signal has been passed to the neighboring nerve cell. This is the process of neurotransmission. 

DRIFT Diffuse reflectance infrared Fourier-transformed specaroscopy... 

Because chemical and structural properties of natural and artificial gems are very similar in this case, the possibilities of Raman and LIBS methods are rather limited. It was found that another laser-based techniques could be very effective for rapid spectroscopic discrimination between natural and synthetic emeralds, rubies, and alexandrite (Armstrong et al. 2000a,b). The first one is DRIFTS (Diffuse Reflectance Fourier Transformed Infra-Red Spectroscopy)... 

DRIFT diffuse reflection Fourier-transform infrared spectroscopy... 

Fig. 7.18. As the electrode reaction consumes ions from the OHP, their concentration is bound to decrease because the ionic drift diffusion from the bulk of the solution can start only after a certain concentration gradient is established.

Secondly, compared to methanol oxidation, the rates of reaction decrease significantly upon oxidation of HMF for the Pt and Pd catalysts. In the case of Pt this decrease is drastic under the mild conditions applied here, indicating a strong interaction of HMF with the Pt surface. In the case of Pd the decrease is less pronounced and for Pd/Al-N even an increase in rate of reaction is found (entries 3 and 15). Probably the interaction of HMF with Pd is less strong, especially in the case of highly dispersed Pd. In order to study the interaction of HMF with noble metals, DRIFT (diffuse reflectance infrared fourier transform) measurements are in progress. 

Hydrated silica gel was modified with APTS (sample 1) and studied by DRIFT (Diffuse Reflectance Infrared Fourier Transform) and CP MAS NMR. The IR spectrum of the modified silica (figure 9.4) shows silane NH, CH and Si-O-Si bands along with silica lattice and surface vibrations. Assignments of IR bands of APTS modified silica are given in table 9.2. 

The introduction of Fourier Transform Infrared Spectroscopy (FTIR) brought along a number of typical solid sample techniques. DRIFTS (Diffuse Reflectance Fourier Transform Infrared Spectroscopy) is probably most commonly known. Another technique, developed specifically for measuring solid, opaque samples is PAS (Photo Acoustic Spectroscopy). This accessory is less known, probably due to its high cost and its rather difficult modus operandi. 

DRIFTS diffuse reflection infrared Fourier transform spectrsocopy... 

The heterogenization of MAO-activated Nd(z 3-C3H5)3 dioxane on MAO-functionalized Si(>2 was reported by T. Riihmer et al. [307]. In situ DRIFT (= diffuse reflectance infrared Fourier transform) spectroscopy and TPRS (= temperature-programmed reaction spectroscopy) were employed... 

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