Materials Literature
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A model based on hexagonal mesopores connected by micropores allows evaluation of the porosity of SBA-15 silicas and elucidation of the literature problems on the subject. The presence of micropores in the walls between the mesopores renders unreliable the surface area determination by the Brunauer−Emmett−Teller equat…
Molecular-dynamics computer simulations of a model Ni nanocrystalline sample with a mean grain size of 12 nm under uniaxial tension is reported. The microscopic view of grain-boundary sliding is addressed. Two atomic processes are distinguished in the interfaces during sliding: atomic shuffling and stress-assisted fre…
Sapphyrin was the first expanded porphyrin to be reported in the literature and remains among the most extensively studied. Much of the interest in this macrocycle reflects its ability to bind anions, a phenomenon that has been examined in solution and in the solid state by a wide range of experimental techniques. In…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSupramolecular Structures from Rod−Coil Block CopolymersMyongsoo Lee, Byoung-Ki Cho, and Wang-Cheol ZinView Author Information Department of Chemistry, Yonsei University, Shinchon 134, Seoul 120-749, Korea, and Department of Materials Science and Engineering and Polymer Rese…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConvergent Dendrons and Dendrimers: from Synthesis to ApplicationsScott M. Grayson and Jean M. J. FréchetView Author Information Department of Chemistry, University of California, Berkeley, California 94720-1460 Cite this: Chem. Rev. 2001, 101, 12, 3819–3868Publication Date…
The [(M+)x([18]crown-6)] supramolecular cations (SC+), in which M+ and [18]crown-6 are alkali metal ions (M+=Li+, Na+, and Cs+) and 1,4,7,10,13,16-hexaoxacyclooctadecane, respectively, form ionic channel structures through the regular stacks of [18]crown-6 in [Ni(dmit)2]-based molecular conductors (dmit2−=2-thioxo-1,3…
A binary Lennard-Jones alloy exhibits an entropically stabilized quasicrystal state in two dimensions at elevated temperatures. We consider the ground states of this model by calculating the convex hull of cohesive energy as a function of alloy composition. Only crystalline structures with rational values of the compo…
Abstract A series of thermotropic polyesters, derived from 4,4′‐biphenol (BP), 3‐phenyl‐4,4′‐biphenol (MPBP), and 3,3′‐bis(phenyl)‐4,4′‐biphenol (DPBP), 4,4′‐oxybisbenzoic acid (4,4′‐OBBA), and other aromatic dicarboxylic acids as comonomers, were prepared by melt polycondensation and were characterized for their ther…
Results are reported on the electron field emission properties of sulfur-incorporated nanocrystalline carbon (n-C:S) thin films grown by hot-filament chemical vapor deposition technique. The lowest turn-on field values observed were around 4.0–4.5 V/μm, which are about half of those measured for films grown without su…
Strukturelle Einzelheiten des Intermediats, das 200 ms nach Beginn der Ca2+-induzierten Rückfaltung von α-Lactalbumin vorliegt, wurden durch zeitaufgelöste Photo-CIDNP-NMR-Methoden ermittelt. Die Rückfaltung bei konstanter Konzentration an Denaturierungsmittel wurde durch laserinduzierte Ionenfreisetzung aus photolabi…
PbZr 0.5 Ti 0.5 O 3 /La 0.5 Sr 0.5 CoO 3 (PZT/LSCO) heterostructures have been grown directly on (100)Si by chemical solution routes. Field-emission scanning electron microscopy and x-ray diffraction analysis show that PZT and LSCO thin films are polycrystalline and entirely perovskite phase. PZT thin films grown on L…
We calculate the low-energy tunneling density of states $\ensuremath{\nu}(\ensuremath{\epsilon},T)$ of an $N$-channel disordered wire, taking into account the electron-electron interaction nonperturbatively. The finite scattering rate $1/\ensuremath{\tau}$ results in a crossover from the Luttinger liquid behavior at h…
A large quantity of metal Zn nanobelts have been synthesized by a simple approach, which involves thermal decomposition of ZnS powder, followed by Zn deposition.
Die Photooxidation einzelner Farbstoffmoleküle (siehe Schema) konnte mit konfokaler Fluoreszenzmikroskopie verfolgt werden. Die selbstsensibilisierte Reaktion mit Singulettsauerstoff führt zu einer Reihe von Produkten, die auf diese Weise erstmals spektral nachgewiesen und unterschieden werden können. Durch quantenche…
A study of the effect of microgravity on biomineralization/remineralization by considering Ca mineral nucleation under gravity and microgravity is presented. The structure of human bone is determined to a large extent by the turnover of the bone, which included nucleation of biominerals adjacent to biosubstrates. Hete…
Sorcin is a 22 kD calcium-binding protein that is found in a wide variety of cell types, such as heart, muscle, brain and adrenal medulla.It belongs to the penta-EF-hand (PEF) protein family, which contains five EF-hand motifs that associate with membranes in a calcium-dependent manner.Prototypic members of this famil…
Among oligosaccharides, trehalose seems to be unique in nature as a bioprotector in drying and freezing processes. To understand the molecular mechanisms underlying the unusual bioprotective properties of trehalose in comparison with other disaccharides, the low-frequency dynamics of aqueous $({\mathrm{H}}_{2}\mathrm{…
We study the charge ordering (CO) in the one-dimensional (1D) extended Hubbard model at quarter filling where the nearest-neighbor Coulomb repulsion and dimerization in the hopping parameters are included. Using the cluster mean-field approximation to take into account the effect of quantum fluctuations, we determine…
The [(M+)x[18]crown-6)] supramolecular cations (SC+), in which M+ and [18]crown-6 are alkali metal ions (M+ = Li+, Na+, and Cs+) and 1,4,7,10,13,16-hexaoxacyclooctadecane, respectively, form ionic channel structures through the regular stacks of [18]crown-6 in [Ni(dmit)2]-based molecular conductors (dmit2+ = 2-thioxo-…
We report on the operation of an integrated gated cathode device using a single vertically aligned carbon nanofiber as the field emission element. This device is capable of operation in a moderate vacuum for extended periods of time without experiencing a degradation of performance. Less than 1% of the total emitted c…