Macro-Brownian motion

Under the action of an applied acoustic field the suggestion was that there would be regions within the polymer where rotation (and vibration) of individual segments were able to take place freely, in phase with the rapid oscillatory movement of the solvent. This segmental movement (termed micro Brovmian motion) was in addition to the movement of the macromolecule as a whole (macro Brownian motion). However, in that segmental motion is a cooperative effect and depends upon the interaction... 

Far below the glass transition temperature (T see Sect. 2.3.4.3) the macro-Brownian motions are frozen in completely, and most of the micro-Brownian motions are frozen in as well ( glassy state ). Near Tg, the micro-Brownian motions set in and become stronger with increasing temperature. The material softens. Finally, upon further raise of temperature, the macro-Brownian motions set in as well, and the polymer can be deformed by applying an external force. 

The rate of all these processes, of course, depends strongly on the temperature in the vicinity of Tg the polymer chains are still relatively inflexible. Thus deformation requires considerable forces, and recovery occurs very slowly. Well above Tg the melt deforms more easily, but the tendency to flow as a result of increased macro-Brownian motion is still outweighed by the elastic recovery. The temperature range for pronounced elastic behavior of the polymer melt depends... 

The molecular movements of the chain determine the elastic range of polymers. In this unique state of rubber like elasticity there is freedom of the micro-Brownian motion of the chain units and a high relaxation time for the macro-Brownian motion of the entire chain. This state can be described as a liquid with a fixed structure U6). 

To bias the direction the macro cycle takes at each of the transformations, temporary barriers would be required in order to restrict Brownian motion in one particular direction. Such temporary barriers are intrinsically present in [3]catenane 20 (Fig. 8 and Scheme 10). Irradiation at 350 nm of , -20 causes counter-clockwise rotation of the light-blue macrocycle to the succinic amide ester (orange) station to give Z,E-20. The light-blue macrocycle cannot rotate clockwise because the purple macrocycle effectively blocks that route. 

In most electroosmotic flows in microchannels, the flow rates are very small (e.g., 0.1 pL/min.) and the size of the microchannels is very small (e.g., 10 100 jm), it is extremely difficult to measure directly the flow rate or velocity of the electroosmotic flow in microchannels. To study liquid flow in microchannels, various microflow visualization methods have evolved. Micro particle image velocimetry (microPIV) is a method that was adapted from well-developed PIV techniques for flows in macro-sized systems [18-22]. In the microPIV technique, the fluid motion is inferred from the motion of sub-micron tracer particles. To eliminate the effect of Brownian motion, temporal or spatial averaging must be employed. Particle affinities for other particles, channel walls, and free surfaces must also be considered. In electrokinetic flows, the electrophoretic motion of the tracer particles (relative to the bulk flow) is an additional consideration that must be taken. These are the disadvantages of the microPIV technique. 

If the polymer chains are crosslinked to form a network, the micro-Brownian motion of the chain segments is not essentially influenced The macro-Brownian motion, that are the motions... 

The phase structure of the phase is at the origin of the piezoelectric effects. While low molar mass Sq liquid crystals flow under the influence of an external mechanical held, the network structure of the Sq elastomers prevents macro-Brownian motions of the mesogens and deformations with large amplitudes are feasible. On the other hand, compared to solid-state crystals, the modulus of the elastomers is smaller by orders of magnitude and, moreover, can be modified by the cross-linking density of the network. With these exceptional properties, S() elastomers offer a new class of electromechanical materials that stimulate theoretical and experimental activities. 

As the name suggests, this method simulates the Brownian motion of macro-molecular or colloidal particles due to random collisions with the surrounding molecules. The collisions are simulated by a random stochastic force, so... 

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