Materials Literature
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The adsorption behavior of 4-cyanobiphenyl (CNBP) has been investigated by means of surface-enhanced Raman scattering (SERS). CNBP appeared to assume a tilted orientation on silver and gold. The presence of the ring C−H band denoted a rather vertical orientation of the biphenyl ring on Ag and Au. On the other hand, co…
The photodissociation of Cr(CO) 6 has been studied using direct dynamics including trajectory surface hopping. The dissociation takes place on a steep excited-state potential surface leading to ejection of a CO ligand within 100 fs in reasonable agreement with time-resolved studies by Fuβ et al. 1-3 Our dynamics studi…
The surface structure of monolayer graphite (MG) on a Ni(111) surface has been investigated using Li + -impact collision ion scattering spectroscopy (ICISS) and reflection high-energy electron diffraction (RHEED). The RHEED pattern showed a 1 ×1 structure for MG formed on the Ni(111) surface, and the ICISS measurement…
The properties of the softening “glass to rubber” dispersion of two archetypal amorphous polymers, polystyrene and polyisobutylene, appear to differ greatly. Previously, these differences have been explained by the larger intermolecular coupling between the repeat units in executing the local segmental motions in poly…
Novel R3TTF-sigma-A compounds 14, 16 and 19 (R3TTF = trial-kyletrathiafulvalene, sigma = saturated spacer, A = polynitrofluoren-9-dicyano-methylene acceptor) incorporating very strong donor and acceptor moieties have been synthesized by condensation of the corresponding R3TTF-sigma-fluoren-9-one diads with malononitri…
Poly(vinyl alcohol), PVA, is amenable to several structural modifications because of the presence of the hydroxyl moiety in the backbone. The chemical versatility of this polymer can be used for the obtainment of new wall-to-wall pH-responsive PVA chemical hydrogels and for the preparation of air-filled microspheres,…
An X-ray diffractometer connected with a molecular-beam epitaxy (MBE) system has been constructed for in situ studies on the growing surfaces of III–V compound semiconductors. This diffractometer is based on the (4+2) type, which has four axes for orienting the sample and two axes for positioning the detector. In addi…
In cubic PbZrO 3 , which undergoes an antiferroelectric phase transition, the distinct disorder of Pb at twelve sites toward the neighboring O is detected for the first time by analyzing high-energy X-ray powder diffraction data. In the charge density distributions, the covalent nature of the Pb–O bond is also reveale…
The triple-helix is a unique secondary structural motif found primarily within the collagens. In collagen, it is a homo- or hetero-tripeptide with a repeating primary sequence of (Gly-X-Y)(n), displaying characteristic peptide backbone dihedral angles. Studies of bulk collagen fibrils indicate that the triple-helix mu…
Block copolymers are known to generate nanoscale microdomains by microphase separation, if they are annealed at a temperature lower than their order-disorder transition temperatures. We attempted to transfer the microdomains onto substrates by only using the reactive-ion etching (RIE) method, which is widely used in s…
Experiments show that the impurities can drastically change grain boundary mobilities in a non-trivial manner. The most widely used type of theoretical model for impurity effects on boundary migration is a one-dimensional, continuum model, based upon several simplifying assumptions. Although several of these assumptio…
In situ Raman spectroscopy was used to determine the rate of polymorph turnover for MK-A, a multipolymorphic compound in development at Merck Research Laboratories. The known crystal forms of MK-A include four anhydrous polymorphs, two hydrates, and numerous solvates. The penultimate and pure steps of this process inv…
Four new isophorone and combined isophorone and thiophene bridged chromophores have been synthesized. All of these new high μβ chromophores possess our newly synthesized tricyanovinyldihydrofuran acceptors. Because of our unique acceptor design, all of our chromophores show high solubility in all organic solvents due…
Single molecule spectroscopy was used to characterize the rotation of fluorescent probe molecules in supercooled o -terphenyl (OTP) just above the glass transition. Rotational motions of spatially isolated individual probe molecules were followed in real time, revealing dynamics that reflect a mosaic of spatially hete…
We have successfully synthesized several new substituted thiophene-based electro-optic chromophores. All of these chromophores have structures similar to FTC but they incorporated our newly designed tricyanovinyldihydrofuran acceptors. Since these acceptors possess an anisotropic structure, all of the chromophores are…
It is important to resolve the structure of Bombyx mori silk fibroin before spinning (silk I) and after spinning (silk II), and the mechanism of the structural transition during fiber formation in developing new silk-like fiber. The silk I structure has been recently resolved by (13)C solid-state NMR as a "repeated be…
Calcite particles are grown in a collagenous matrix using a counter-diffusion arrangement. Although microstructural analysis revealed a heterogeneous intergrowth of organic and inorganic phases within the particles, the composite growth is rather a consequence of local chemical environment that is not specific to the…
We study experimentally and theoretically the hydrodynamic coupling between Brownian colloidal particles diffusing along a linear channel. The quasi-one-dimensional confinement, unlike other constrained geometries, leads to a sharply screened interaction. Consequently, particles move in concert only when their mutual…
A novel process for fabrication of metal nanostructure arrays directly on glass substrates is described. An aluminum film was sputter-deposited on a glass substrate coated with a tin-doped indium oxide (ITO) film. The films were then anodically oxidized to obtain a porous alumina template, with pore diameters ranging…
A new triclinic perovskite, BiNiO3, has been synthesized at a high pressure of 6 GPa in an oxidizing atmosphere. Structure refinements based on synchrotron X-ray powder diffraction and bond-valence calculations revealed a disproportionation of the Bi ions into Bi3+ and Bi5+, both being located in distorted oxygen octa…