Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Spider dragline silk is a semicrystalline protein polymer in which alanine-rich crystalline regions are connected by soft glycine-rich linkers that, in dry fibers are quiescent but become motionally active when plasticized by water. Using solid-state NMR to probe molecular motion and orientation of selectively 13 C-la…
We have studied the energetics and mobility of neutral hydrogen in alumina ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ using ab initio density-functional calculations. The mobility of hydrogen was studied in corundum $(\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3})$ as well as in liquid alumina. Using bot…
A novel carbon−sulfur (C 2 S) analogue of polyacene has been synthesized and characterized. The polymer is composed of a nondegenerate trans − cisoid polyacetylene backbone in which all hydrogen atoms are replaced with sulfur atoms to form thiophene rings that are fused into a linear cross-conjugated ladder-type struc…
ZnO nanowires were grown in gram quantities on graphite flakes (as collector) using the vapour transport and condensation approach. The yield, defined as the weight ratio of ZnO nanowires to the original graphite flakes, has been studied thoroughly by tuning the various growth parameters such as pressure and temperatu…
A comparative analysis of the polymorphic behavior of samples of isotactic polypropylene (iPP) prepared with heterogeneous Ziegler−Natta catalysts and with a single-center homogeneous metallocene catalyst is presented. Different samples of Ziegler−Natta iPP, prepared with MgCl 2 -supported catalysts modified by adding…
Abstract The water sorption characteristics of banana fiber–reinforced polyester composites were studied by immersion in distilled water at 28, 50, 70, and 90°C. The effect of hybridization with glass fiber and the chemical modification of the fiber on the water absorption properties of the prepared composites were al…
Dendrimers are well-defined and highly branched macromolecules. By utilizing their capsular architectures, dendrimers encapsulating various catalytically active species can be prepared, which often bring about unique catalysis. Treatment of the alkylated PPI dendrimer with 4-diphenylphosphinobenzoic acid and [PdCl(C3H…
The electronic and magnetic properties of ${\mathrm{S}\mathrm{r}\mathrm{F}\mathrm{e}\mathrm{O}}_{3\mathrm{\text{\ensuremath{-}}}\ensuremath{\delta}}$ single crystals with controlled oxygen content ($0\ensuremath{\le}\ensuremath{\delta}\ensuremath{\le}0.19$) have been studied systematically by susceptibility, transport…
Molecular recognition of gases is an emerging area of chemistry. Supramolecular chemistry helps us to understand how gases interact with biological molecules and offers delicate insights into the mechanisms of their physiological activity. Principles of molecular recognition have been used for gas sensing, and have pr…
Hierarchical eight-arm, star-shaped PbS single crystals have been successfully synthesized by the controlled release of sulfide ions from thioacetamide (TAA) at 80 °C in aqueous solutions of lead acetate and acetic acid. The unique star-shaped PbS crystals have eight symmetric arms along the 〈111〉 directions, each of…
We show that the interaction of a particle with a directionally solidified interface induces the onset of morphological instability provided that the particle-interface distance falls below a critical value. This instability occurs at pulling velocities that are below the threshold for the onset of the Mullins-Sekerka…
The buildup of poly(L-glutamic acid) (PGA) and poly(L-lysine) (PLL) multilayers on silica and titanium surfaces, with and without an initial layer of polyethyleneimine (PEI), was investigated and characterized by means of in situ ellipsometry and quartz crystal microbalance with dissipation. A two-regime buildup was f…
Abstract Polymethylmethacrylate (PMMA)/silica nanocomposites are prepared by solution polymerization in this project and the resulting materials are subjected to characterization to evaluate thermal, mechanical, and fire properties. IR results show that both (3‐acryloxypropyl)methydimethoxy‐silane (APMDMOS) and (3‐acr…
With the aim of future applications in quantum mechanical embedding in extended systems such as crystals, we suggest a simple and computationally efficient method which enables construction of a set of nonorthogonal highly localized one-electron orbitals for periodic nonmetallic crystals which reflect their chemical n…
Methods for calculating an electron density of a periodic crystal constructed using non-orthogonal localised orbitals are discussed. We demonstrate that an existing method based on the matrix expansion of the inverse of the overlap matrix into a power series can only be used when the orbitals are highly localised (e.g…
The generation of surface plasmon polaritons (SPP's) at isolated nanoholes in 100 nm thick Au films is studied using near-field scanning optical microscopy (NSOM). Finite-difference time-domain calculations, some explicitly including a model of the NSOM tip, are used to interpret the results. We find the holes act as…
In this paper we discuss both the crystallographic aspects that govern the general features of the cores of ⟨111⟩ screw dislocations in bcc metals and the role of interatomic bonding that is specific to given materials. This analysis is carried out by comparing the results of two atomistic calculations of dislocations…
We investigate 1, 2, 3, and 4 monolayers of iron grown on the (001) surface of ZnSe using spin density functional theory, plane-wave expansion, and ultrasoft pseudopotentials. An ideal structure of the interface is plausible due to the very small lattice mismatch between both materials. However, we observe dramatic de…
Nonequilibrium dynamics at interfaces is generally driven by a chemical potential. Here we demonstrate a generic technique to derive the basic equations of motion, boundary conditions and the chemical potential in a consistent way from fundamental variational principles. As a particular example, we consider a solid su…
We elucidate the physical mechanisms by which electromagnetic excitations in planar chiral waveguides exhibit broken time reversal and parity symmetries as recently observed in metallic nanostructures (Phys. Rev. Lett. 91, 247404 (2003)). Furthermore, we show that concomitant with these broken symmetries the electroma…