Materials Literature
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Abstract A genetic algorithm (GA) based method for solving crystal structures directly from powder diffraction data has been developed. The method is based around fitting the diffraction data generated from trial structures against the measured diffraction data and has the ability to handle flexible molecules and mult…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDendrimers Containing Organometallic Moieties Electronically CommunicatedIsabel Cuadrado, Carmen M. Casado, Beatriz Alonso, Moisés Morán, José Losada, and Vitaly BelskyView Author Information Departamento de Química Inorgánica, Universidad Autónoma de Madrid, 28049-Mad…
We examine the influence of attractive interactions on the phase behavior of rodlike colloids. We model the rodlike particles by spherocylinders, for which the phase diagram, in the absence of attraction, is known for arbitrary aspect ratio. We consider the case that the attraction is due to depletion forces caused by…
Crystal structures of ( E )-azobenzene (1), ( E )-2,2′- dimethylazobenzene (2), ( E )-3,3′-dimethylazobenzene (3) and ( E )-4,4′-dimethylazobenzene (4) were determined by X-ray diffraction at various temperatures. An apparent shrinkage of the N=N bond and its temperature dependence were observed and are interpreted in…
Low-water content reverse micelles have been formed in cyclohexane employing Triton X-100 or AOT (bis(2-ethylhexyl) sulfosuccinate sodium (salt) as the surfactant. Steady-state and time-resolved luminescence quenching studies, using Ru(bpy) 3 2+ as the luminophore and Fe(CN) 6 3 - or MV 2+ as the quencher, have shown…
A survey was compiled of several characteristics of the intersubunit contacts in 58 oligomeric proteins, and of the intermolecular contracts in the lattice for 223 protein crystal structures. The total number of atoms in contact and the secondary structure elements involved are similar in the two types of interfaces.…
Microphase separation in semicrystalline block copolymers can be driven by two forces: thermodynamic incompatibility between the blocks in the melt or crystallization of one or more blocks. The diblock copolymers investigated here are polyethylene- b -poly(3-methyl-1-butene), all containing ≈26 wt % ethylene, prepared…
This work synthesizes new adamantane-based polyimides by reacting 1,3-bis[4-(4-aminophenoxy)phenyl]adamantane ( 4 ) with various aromatic tetracarboxylic dianhydrides. The poly(amic acid)s have number-average molecular weights ( M n ) of 39 000−139 000. The M n 's of soluble polyimides 7 d and 7 e are 108 000 and 89 0…
The molecular-dynamics technique involving the rapid cooling of a liquid to simulate an amorphous solid has been used for several years. Despite the success of the technique, the method has lacked a physical justification, and the cooling rates have been assumed to be too fast. In this paper an analysis of thermal spi…
There has been a controversy about the self-aggregation of 5,10,15,20-tetrakis[4-( N -methyl)pyridinium]porphyrin (TMPyP(4)) in water. In order to make clear whether TMPyP(4) forms a dimer in water, 1 H NMR and UV−vis spectroscopic studies of 5-phenyl-10,15,20-tris[4-( N -methyl)pyridinium]porphyrin (TriMPyP), 5,10-di…
Macromolecular architecture is receiving increasing interest as the search for new tailor-made polymeric materials with strictly specified properties intensifies. Many research groups are now focusing their interest on dendritic macromolecules [dendron (Greek) = treelike, highly branched] i.e. dendrimers and hyperbran…
Abstract The degree of branching (DB) as well as the ANB (average number of branches) of polymers obtained from polycondensation of AB 2 and AB m ‐type monomers in general is analyzed in detail on the basis of kinetic considerations. Various possibilities for the enhancement of the DB of hyperbranched polymers beyond…
The algorithm for the dissipative particle dynamics (DPD) fluid, the dynamics of which is conceptually a combination of molecular dynamics, Brownian dynamics, and lattice gas automata, is designed for simulating rheological properties of complex fluids on hydrodynamic time scales. This paper calculates the equilibrium…
Like other bacteria, Bacillus subtilis possesses a family of homologous small acidic proteins (CspB, CspC and CspD, identity >70%) that are strongly induced in response to cold shock. We show that deletion of cspC or cspD genes did not result in a detectable phenotype; in contrast, csp double mutants exhibited severe…
High quality ZnO thin film was grown by Laser MBE. A pure ceramic ZnO target was ablated by the KrF laser pulses (248 nm, 10 Hz, 1 J/cm2) in an ultra high vacuum to deposit ZnO film on sapphire (0001) substrate. The lateral grain size was about 50 nm for the sample with thickness of 55 nm. At room temperature, the pea…