Wulf model

Williams domains, dynamic scattering 243 ff write mechanism, low frequency 390 write speed, laser addressed devices 478 Wulf model, smectogens 417... 

For Au NPs supported on the MgO(lOO) surface TEM has shown that even very small clusters are well faceted and fee ordered (36). This is explained by the strong adhesion and small lattice mismatch ( 3%) between Au and MgO, which favors epitaxial Wulf-Kaischew-Iike morphologies. For larger lattice mismatch (e.g. Pd/MgO) NPs may be significantly strained and contain dislocations. To model these effects theoretically requires carefiil treatment of the metal-substrate interaction (37). In contrast for weakly interacting supports, such as graphite, strained decahedral and icosahedral clusters have been observed by TEM (33). 

Model for regulation of cellulose biosynthesis in A. xylinum (reprinted from Polymer Degradation and Stability, vol. 59, E.J. Vandamme, S. De Baets, A. Vanbaelen, K. Joris and P. De Wulf, Improved production of bacterial cellulose and its application potential, 93-99, copyright (1998), with permission from Elsevier). 

Different molecular models for the SmC phase can be separated into two main classes that actually correspond to different molecular mechanisms of the smectic A-smec-tic C transition. Some models (for example, those of McMillan and Meyer [81 ] and Wulf [80]) imply that the molecular rotation about the long axis is frozen out in the smectic C phase. It seems to be even more important that in these models the smectic A-smec-tic C transition is governed by the ordering of molecular short axes while the tilt of the long axes occurs as a consequence. By contrast, in other models [82] the transition is directly related to the tilt of the long axes and the biaxiality of the smectic C phase is neglected. 

It should be noted that the assumption of a strongly asymmetric orientational distribution of molecular short axes in the smectic C phase seems to be in contradiction with experiments [85]. Some other models also do not have any experimental support so far. Goodby et al. [87] and de Jeu [88] have studied the influence of electric dipole and molecular shape on the stability of the smectic C phase. The results do not support the models of Wulf [80] and Cabib and Ben-guigui [82] but reveal the importance of transverse dipoles. Thus there is some experimental evidence in favor of the model proposed by Van der Meer and Vertogen. 

---