Dynamic dichroic

In the dynamic transmission mode, information about two-dimensional dynamic dichroic differences can be attained [46]. It is useful to study uniaxially oriented polymers such as strongly elongated fibres. However, the orientation of most polymer films should be considered biaxial, even with uniaxially drawn films, which still show slight biaxial orientation at the surface [52]. This fact suggests that the two-dimensional dynamic dichroic data obtained from transmission mode is not necessarily adequate for evaluating most (biaxially oriented) polymer films. 

The complete theory of how the output signals from the five lock-in amplifiers are treated in order to obtain static and dynamic spectra was originally given by Noda et al. [3] and Noda [4,5]. The inclusion of the full theory is beyond the scope of this book. Suffice it to say that the end result is calculation of the average static absorbance spectmm, the in-phase and quadrature components of the parallel and perpendicular absorbances, and the static and dynamic dichroic difference spectra. Of these, the in-phase and quadrature DIRLD spectra give the most important information about the rheological behavior of the polymer on a submolecular level. 

The dynamic dichroic difference signal takes the form... 

Finally, reference is made to the dynamic dichroic absorption difference, which is related to an absorption change induced by an external time-dependent perturbation. Dynamic absorption spectroscopy is performed with linearly polarized IR light and serves for example to detect intermolecular hydrogen bonds in polyamides of the structure... 

Single-bilayer DODAC (6) vesicles Magnetite particles prepared in situ in vesicles from Fe2+/Fe3+ and OH" Static and dynamic polarized and depolarized light scattering and static and time-resolved dichroic anisotropy, as well as conventional magnetization vs applied magnetic field determinations were used for characterization 794... 

Another strategy is to utilize single multiband dichroic mirrors and emission filters and separate exciter filters either in an external slider or filter wheel. This will preserve the image registration and reduce mechanical vibrations, but the trade offs are a reduced brightness of the fluorescence, limitations on how many different probes can be separated, and reduced dynamic range and sensitivity due to the necessary color CCD camera. 

B) Data Analysis. Irradiation was performed with a high pressure mercury lamp (250W, Ushio Electrics Co.). The two dichroic absorbance components of HNMA and Cyclophane at 393.5tun and 402nm were monitored at room temperature after irradiating the sample over different time intervals with linearly polarized light at 365nm. The reorientation dynamics of these molecular tracers were obtained from the analysis of the time-dependent induction efficiency qft) which is defined as" r (t) = 100. ODx(t) - ODii (t) /ODo (1)... 

The emissions of two fluorophores are separated by a dichroic in order to record two fluorescent proteins synchronously, as required for the exact superposition of proteins participating in highly dynamic processes. If the two channels are not precisely in the same focus, a lens should be inserted into one channel. 

Dynamic infrared linear polarised spectra of thermoplastic polyester urethane and nylon-6 films were recorded under a varying sinusoidal strain. Dichroic spectra were calculated from the dynamic polarised spectra. The large bipolar bands in the dichroic in-phase spectra, caused by large frequency shifts of the original monopolar absorption bands, were ascribed to hydrogen bonds. 29 refs. 

A dynamic linear infrared dichroism study was carried out as a function of temperature on isotropic and cold drawn HDPE using a rapid-scan setup. The dynamic in-phase dichroic spectrum and its components (parallel and perpendicular polarised spectra) were analysed. 15 refs. 

DIRLD (dynamic infrared linear dichroic) spectra of prestretched isotactic polypropylene were recorded. The line shape features in the in-phase spectra are described on the basis of frequency shifts and absorption amplitude... 

Ultimate dichroic ratio Dynamic infrared linear dichroism Observation period Time... 

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