Dual polarization modulation

Nafie LA (2000) Dual polarization modulation a real-time, spectral-multiplex separation of circular dichroism from linear birefringence spectral intensities. Appl Spectrosc 54 1634-1645... 

VCD instruments, based also on the principles depicted in Figure 13, are in comparison to the ECD instruments, relatively new products on the market. Thus, there have been further developments. Two of them should be mentioned, namely, the use of the Fourier transform technology and the use of a second PEM with and without a second polarizing element. This dual polarization modulation (DPM) method increases the quality of the VCD spectra. Also, the Raman spectrometers for ROA, with which the difference of scattered left and right circularly polarized Raman light is measured, have been developed to a standard that allows systematic chiroptical analyses, nowadays. 

L. A. Nafie and R. K. Dukor, The use of dual polarization modulation in vibrational circular dichroism spectroscopy, in Chirality Physical Chemistry, J. M. Hicks, Ed., American Chemical Society, Washington, DC, 2002, Vol. 810, p. 79. 

If circular polarization modulation is carried out simultaneously, and in-phase, in both the incident and the scattered beam, one obtains the first form of dual circular polarization (DCPl) ROA [34], with a normalized CID given by ... 

Subsequently, we found that a zeroth-order QWP could be employed successfully in the laser beam for ICP measurements, and from that point it was relatively straightforward to carry out DCP ROA measurements [35]. If desired, linear polarization modulation can be set up by using half waveplates in place of the QWPs. In the following sections we provide details associated with present operation of our dual QWP ROA spectrometer. 

Nafie LA, Buijs H, Rilling A et al (2004) Dual source Fourier transform polarization modulation spectroscopy an improved method for the measurement of circular and linear dichroism. Appl Spectrosc 58 647-654... 

A major emerging application of optical fibers is in the distritoion of radio signals for broadband services and wireless communication systems fiber can provide a low loss backbone with large bandwidth. Snch systems require optical sources with narrow linewidth, low noise, and moderate output power. Externally modulated single mode fiber lasers are therefore well suited to applications in these systems. Dual wavelength fiber lasers (e.g., dual polarization mode DFB lasers) are also potentially useful for the generation of millimeter wave radio carriers. 

Yushchenko DA, Shvadchak W, Bilokin MD, Klymchenko AS, Duportail G, Mely Y, Pivovarenko VG (2006) Modulation of dual fluorescence in a 3-hydroxyquinolone dye by perturbation of its intramolecular proton transfer with solvent polarity and basicity. Photochem Photobiol Sci 5 1038-1044... 

Of particular importance is the study of photophysical properties and the coupling of emission behavior to chemical reactivity. In addition, the further study of the heterocyclic-substituted platinum-1,2-enedithiolates as room temperature dual emitters is warranted. The dual emitters not only allow conventional detection methods but new ratiometric, double-modulation and polarization-based methods to be incorporated into detection strategies (34, 91, 92). At least two of these methods were development solely for the heterocyclic substituted 1,2-enedithiolates. While these detection methods evolved to monitor molecular oxygen, it is likely, given their unique... 

Based on the interplay between the complexing ability of crown-ethers or cry tands and the dual fluorescence (monomer/excimer) of aromatic rings (especially anthracene), new supramolecular receptors were designed and synthesized. Modulation of the fluorescrace (wavelengA, quantum yield, excimer/monomer ratio) of different photoactive systems is observed as a specific response to the complexation of metal (Na ", K" ", Ag" ", Tl", Rb" ") or molecular Ql3N -(CH2)n- NH3) cations. These properties could be used for light frequency conversion (anthraceno-coronand), detection and estimation of cations at low concentration (craterophanes, tonnelet) and evaluation of the solvent polarity (semaphorene). 

An intrinsic time-dependent one-dimensional (ID) model and a macro two-dimensional (2D) model for the anode of the DMFC are presented in [178]. The two models are based on the dual-site mechanism, which includes the coverage of intermediate species of methanol, OH, and CO on the surface of Pt and Ru. The intrinsic ID model focused on the analysis of the effects of operating temperature, methanol concentration, and overpotential on the transient response. The macro 2D model emphasizes the dimensionless distributions of methanol concentration, overpotential and current density in the CL which were affected by physical parameters such as thickness, specific area, and operating conditions such as temperature, bulk methanol concentration, and overpotential. The models were developed and solved in the PDEs module of COMSOL Multiphysics, giving good agreement with experimental data. The dimensionless distributions of methanol concentration, overpotential, and current density and the efficiency factor were calculated quantitatively. The models can be used to give accurate simulations for the polarizations of methanol fuel cell. 

A new solid-state MAS NMR method involving dual-band selective double cross polarization for heteronuclear polarization transfer between dilute spins has been described by Zhang et alP A sinusoidal modulation scheme has been described for selective heteronuclear polarization transfer between two dilute spins in double cross polarization MAS NMR spectroscopy. During the second cross polarization, the C rf amplitude is... 

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