Probe setup

Fig. 6.7 (a) The variation of electrical conductivity of PVA-EG hybrid with increasing graphene content. Inset shows the dependence of dielectric constant for the hybrid, (b) The variation of conductivity of the polystyrene-graphene hybrid with filler content. Inset shows the four probe setup for in-plane and transverse measurements and the computed distributions of the current density for in-plane condition (reference [8]). 

Fig. 22. Schematic of a four-point probe setup. The djs value and its correction factor are typically provided by the equipment company.

Femtosecond visible pump - midinfrared probe setup for the study of protein dynamics. Isomerization in Photoactive Yellow Protein... 

This shows that by varying the intensity of an ultrashort laser pulse, the population transferred to the various neutral electronic states of Na2 can be modified. Recording the transient ion signal in a pump-probe setup can serve to monitor and control the achieved result. 

One of the basic unit operations is dry mixing that is used in most manufacturing schemes. In Fig. 10.6, an example of the use of Raman monitoring for blend control is shown. In this case the blending procedure is very fast and the mixture is well blended within the 5 min used. De Beer et al. used an in situ Raman immersion probe setup to study an ibuprofen-xanthan gum... 

Typically, one works with thin, round semiconductor wafers, ranging in size from 5 inches to less than a quarter inch in diameter, and measures their resistivities using a four-point probe setup. Suppose you use a four-point probe to measure the resistivity of an n-type (p-doped) Si sample. A micrometer tells you that the average thickness ( ) of the 30-inch diameter wafer is 0.408 mm. The spacing on the probe is 0.050 inch. You collect the following current-voltage data at room temperature ... 

The first publication on the effect of non-reactive metal cations on the absorption spectrum of the hydrated electron was published in 1965. A systematic study of the salt concentration effect on the hydrated electron absorption spectrum in very concentrated (up to 15 M) aqueous solutions of LiCl was done by IV Kreitus in 1985, then, resumed by P Krebs and co-workers in 1999. With the development of ultrafast laser pump-probe setup, a few publications noted... 

The chapter is organized as follows. In the remainder of the introduction the investigated molecular systems are introduced. The experimental section describes a typical pump-probe setup for experiments with a very high time resolution. Then the transient absorption and the contributing processes are discussed. In the fourth section a model of the reaction mechanism is developed from the experimental findings. Then we discuss briefly the situation of parallel reaction channels, and finally the results and conclusion are summarized. 

When a built-in self test is not feasible, we encounter difficulties because primary input signals cannot be easily provided within a standardized probe setup. To our knowledge, no commercial testing equipment is available that allows a set of primary stimuli like acceleration, pressure, torque, or mass flow to be applied to the transducer elements of sensor chips on the wafer level, with the required speed and precision. At the moment we are therefore left with purely electrical stimuli for testing microsensor devices. 

D.C. Electrical resistivity measurements of the pellets were carried out from room temperature to 690 K using two probe setup. Resistivity was calculated using the equation,... 

Because of its simplicity, Langmuir probes have found widespread use for diagnosing plasmas. However, care must be exercised when doing the measurements, especially in RF plasmas, as the time-varying plasma potential can corrupt the probe characteristic. Also, a theory is needed to analyze the characteristic and extract the plasma parameters. Such theory is not always available, depending on plasma parameters and probe design. Finally, the probe must introduce as small as possible a disturbance to the plasma, and this is not easy to achieve. Currently, rather sophisticated Langmuir probe setups exist that can record I-V characteristics and extract the plasma parameters with substantial spatial and especially time (ps) resolution. 

Figure 2 Schematic diagram of the experimental pump-and-probe setup as used in the studies of the OH + CO—> H + CO2 reaction in which H atoms are detected by VUV-LIF.

Figure 4.3 shows a pump-probe setup used to measure the transient absorption in the visible spectral range. It is based on two noncollinearly phase-matched optical parametric amplifiers (NOPAs) [16, 17], which are pumped by a common laser system. In this way, the generated pump and probe pulses are perfectly synchronized with respect to each other. As pump laser, regenerative Ti sapphire amplifier systems are usually used, which deUver near-infrared (NIR) pulses at around 800 nm with pulse durations in the order of 100 fs, a repetition rate of 1 kHz, and pulse energies at the rniUijoule level. 

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