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141.
We investigate the microphases of asymmetric AB diblock copolymers confined to thin films in the strong segregation limit under the application of electric fields. We evaluate the free energy of a given set of possible phases and present phase diagrams for diblock copolymers with a cylindrical bulk phase in dependence of the film thickness and the attraction between the confining walls and the A or B monomers. This is done for different field strengths and volume fractions. We find that with increasing field strength structures show a preference for alignment with the field. The alignment is stronger when the permittivity of the minority monomer is larger than that of the majority monomer. Depending on the strength of the wall potential and the film thickness, the walls can become completely wetted by the minority monomer. 相似文献
142.
143.
Mateja Pogorevc Ulrike T. Strauss Marianne Hayn Kurt Faber 《Monatshefte für Chemie / Chemical Monthly》2000,220(2):639-644
Biocatalytic resolution of the tertiary terpene alcohol (±)-linalool was accomplished via hydrolysis of its corresponding acetate ester using two highly enantiospecific enzymes (E > 100). The latter were identified in a crude cell-free extract of Rhodococcus ruber DSM 43338 and could be separated by (partial) protein purification. Since they showed opposite enantiopreference, they were
termed (R)- and (S)-linalyl acetate hydrolase (LAH). The activity and selectivity of the enzyme preparations was markedly dependent on the fermentation
conditions. 相似文献
144.
Patrice Castignolles Marianne Gaborieau Emily F. Hilder Ewan Sprong Christopher J. Ferguson Robert G. Gilbert 《Macromolecular rapid communications》2006,27(1):42-46
Summary: Oligo(acrylic acid)s, produced by RAFT polymerization, have been separated and analyzed for the first time by capillary zone electrophoresis. The resolution obtained by capillary electrophoresis in borate buffers is far higher than that currently achieved using size exclusion chromatography. This work demonstrates that capillary electrophoresis is the technique of choice for the characterization of oligomers of acrylic acid and of other water‐soluble monomers involved in emulsion polymerization processes.
145.
Marianne Akian St��phane Gaubert Bas Lemmens 《Journal of Fixed Point Theory and Applications》2011,9(2):295-325
We study the stable behaviour of discrete dynamical systems where the map is convex and monotone with respect to the standard
positive cone. The notion of tangential stability for fixed points and periodic points is introduced, which is weaker than
Lyapunov stability. Among others we show that the set of tangentially stable fixed points is isomorphic to a convex inf-semilattice,
and a criterion is given for the existence of a unique tangentially stable fixed point. We also show that periods of tangentially
stable periodic points are orders of permutations on n letters, where n is the dimension of the underlying space, and a sufficient condition for global convergence to periodic orbits is presented. 相似文献
146.
Takwa M Larsen MW Hult K Martinelle M 《Chemical communications (Cambridge, England)》2011,47(26):7392-7394
Based on molecular modelling, the enzyme Candida antarctica lipase B was redesigned as a catalyst for the ring opening polymerization of D,D-lactide. Two mutants with 90-fold increased activity as compared to the wild-type enzyme were created. In a preparative synthesis of poly(D,D-lactide) the mutants greatly improved the rate and the degree of polymerization. 相似文献
147.
Spontaneous edge currents are known to occur in systems of two space dimensions in a strong magnetic field. The latter creates
chirality and determines the direction of the currents. Here we show that an analogous effect occurs in a field-free situation
when time reversal symmetry is broken by the mass term of the Dirac equation in two space dimensions. On a half plane, one
sees explicitly that the strength of the edge current is proportional to the difference between the chemical potentials at
the edge and in the bulk, so that the effect is analogous to the Hall effect, but with an internal potential. The edge conductivity
differs from the bulk (Hall) conductivity on the whole plane. This results from the dependence of the edge conductivity on
the choice of a selfadjoint extension of the Dirac Hamiltonian. The invariance of the edge conductivity with respect to small
perturbations is studied in this example by topological techniques
Mathematics Subject Classification (2000). 81Q10, 58J32 相似文献
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