Blue external fields

FIGURE 13.13 The magnetic moments (blue arrows) of the two possible spin states of the methine proton affect the chemical shift of the methyl protons in 1,1-dichloroethane. When the magnetic moment is parallel to the external field if.o (green arrow), it adds to the external field and a smaller 3 0 is needed for resonance. When it is antiparallel to the external field, it subtracts from it and shields the methyl protons. 

Figure 13.1 (a) Nuclear spins are oriented randomly in the absence of an external magnetic field but (b) have a specific orientation in the presence of an external field, B0. Some of the spins (red) are aligned parallel to the external field while others (blue) are antiparallel. The parallel spin state is slightly lower in energy and therefore favored. 

M. Yamada, N. Nada, M. Saitoh, and K. Watanabe, First-order quasi-phase matched LiNbOs wave-guide periodically poled by applying an external-field for efficient blue second-harmonic generation. Applied Physics Letters 62(5), 435-436 (1993). 

When a chiral material is added to a nematic liquid crystal at low concentrations, the pitch p appears to vary linearly with the concentration. A mixture of two compounds of opposite chirality can produce a nematic phase at a certain composition. At this compensation point, the pitch becomes infinite. Unwinding of helical structures can be achieved by external fields. Finally, it is mentioned that, for chiral nematics with relatively short pitch, there exist several intermediate phases known as the blue phases between the isotropic and the chiral nematic phases. These blue phases are... 

Fig. 4 Zoom on the C4—09 bond of an isocontour of the density difference, where pp Q is field Ifee and pp is computed for an external field strength of 1.3 V/nm applied in z direction (panel a) and —z direction (panel b) at the CAM-B3LYP/6-311+G(d,p) level for the equilibrium geometry of the field free S-SPl molecule. Isocontour value is 0.0001 lel/A. The insets show the overall molecule oriented as in Fig. 1. A positive difference is shown in blue and a negative one in yellow. A negative difference (yellow, panel a) indicates that the finite field electron density is larger than that of the neutral. A positive difference (blue, panel b) indicates that the...

Fig. 8.1 Spin wavellinction in an external field of 0.33 T, which at the moment of crossrecombination collapses onto a singlet state for pairs (1,4). a Nuclear configuration -bi -I-2 +3 +4> and b I -1-1 —2 -I-3 -I-4). Number in subscript represents the radical where the magnetic nucleus resides. Black and red line represents (respectively) the singlet and triplet probability simulated using Vftot throughout green and blue dots represent the same using the decomposition method. After 0.1 ps, the spin wavefunction for pair 2, 3 is shown...

The operation of photocells and photomultipliers is based on the external photoelectric effect. Photons impinging on the surface of a photosensitive cathode (photocathode) knock out electrons which are then accelerated in the electrical field between the cathode and the anode and give rise to electric current in the outer circuit. The spectral sensitivity of a photocell depends on the material of the photocathode. The photocathode usually consists of three layers a conductive layer (made, e.g., of silver), a semiconductive layer (bimetallic or oxide layer) and a thin absorptive surface layer (a metal from the alkali metal group, usually Cs). A photocathode of the composition, Ag, Cs-Sb alloy, Cs (blue photocell), is photosensitive in the wavelength range above 650 nm for longer wavelengths the red photocell with Ag, Cs-O-Cs, Cs is used. The response time of the photocell (the time constant) is of the order of 10" s. 

Figure 1. Schematics of the continuous chaotic stirrer developed by Kim and Beskok [25], The stirrer consists of periodically repeating mixing bocks with zeta potential patterned surfaces (a) and an electric field parallel to the x-axis is externally applied resulting in an electroosmotic flow (b). Combining a unidirectional (x-direction) pressure-driven flow (c) with electroosmotic flow under time-periodic external electric field (in the form of a Cosine wave with a frequency ra), a 2-D time-periodic flow is induced to achieve chaotic stirring in the mixer. Two fluid streams colored with red and blue are pumped into the mixer from the left and are almost well mixed after eight repeating mixing blocks for Re = 0.01, St = I2%, Pe= 1,000, and T = 0.8(d).

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