Materials Literature
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A new strategy of scrolling a lamellar precursor was designed to form a ribbonlike structure. In a simple chemical route involving an oxidation−dehydration process, single-crystalline quasi-aligned submicrometer CuO ribbons were synthesized on a copper surface. Electron microscopic studies indicate that these ribbons…
Extracellular polymeric substances (EPS) constitute a heterogeneous mixture of polyelectrolytes that mediate biomineralization and bacterial adhesion and stabilize biofilm matrixes in natural and artificial environments. Although nucleic acids are exuded extracellularly and are purported to be required for biofilm for…
Temperature-sensitive core–shell nanostructures are synthesized by functionalizing a hydroxyl-terminated dendrimer with a reversible addition-fragmentation chain transfer (RAFT) polymerization chain-transfer agent. RAFT polymerization of N-isopropylacrylamide produces a shell around the dendrimer (see Figure). In aque…
A Green's function formalism is used to calculate the spectrum of excitations of two neighboring impurities implanted in a semi-infinite ferromagnetic. The equations of motion for the Green's functions are determined in the framework of the Ising model in a transverse field and results are given for the effect of the…
Spin-polarized dc electric current flowing into a magnetic layer can induce precession of the magnetization at a frequency that depends on current. We show that addition of an ac current to this dc bias current results in a frequency modulated (FM) spectral output, generating sidebands spaced at the modulation frequen…
An explicit expression for the quadratic density-response function of a many-electron system is obtained in the framework of the time-dependent density-functional theory, in terms of the linear and quadratic density-response functions of noninteracting Kohn-Sham electrons and functional derivatives of the time-depende…
The dynamics of moving vortex lattice is considered in the framework of the time dependent Ginzburg - Landau equation neglecting effects of pinning. At high flux velocities the pinning dominated dynamics is expected to cross over into the interactions dominated dynamics for very clean materials recently studied experi…
We report on the synthesis and measurements of the temperature dependence of resistivity, R(T), the penetration depth, l(T), and upper critical magnetic field, Hc2(T), for polycrystalline samples of dodecaboride ZrB12 and diboride MgB2. We conclude that ZrB12 as well as MgB2 behave like simple metals in the normal sta…
Steps with spacings of microns form on top of mesas fabricated on Si(111) that is annealed at temperatures where sublimation becomes important. Upon annealing, mesas first develop ridges along their edges, effectively creating craters which then become step-free by a step flow process described in the literature. Due…
Recent fluorescence spectroscopy experiments on single wall carbon nanotubes reveal substantial deviations of observed absorption and emission energies from predictions of noninteracting models of the electronic structure. Nonetheless, the data for nearly armchair nanotubes obey a nonlinear scaling relation as a funct…
We present results of a density functional theory study of MnO in the wurtzite structure. Our motivation is provided by recent experiments reporting ferromagnetism in Mn-doped wurtzite-structure ZnO. We find that wurtzite MnO (a) is not strongly energetically disfavored compared with the ground state rocksalt MnO, (b)…
The paper describes the purification, biochemical characterization, sequence determination, and classification of a novel thermophilic hydrolase from Thermobifida fusca (TfH) which is highly active in hydrolyzing aliphatic-aromatic copolyesters. The secretion of the extracellular enzyme is induced by the presence of a…
Additive primary color-space has been completed by the discovery of the first green polymeric electrochromic. Mixing any two of the three additive primary colors (red, green, and blue (RGB)) produces thousands of colors (see Figure) resulting from the tones of polymers in different oxidation states. It is envisioned t…
We show that the nuclear spin dynamics in the single-molecule magnet Mn12-ac below 1 K is governed by quantum tunneling fluctuations of the cluster spins, combined with intercluster nuclear spin diffusion. We also obtain the first experimental proof that-surprisingly-even deep in the quantum regime the nuclear spins r…
Recent experiments claimed successful synthesis of cubic boron-carbonitride compounds BC2N with an extreme hardness second only to diamond. In the present Letter, we examine the ideal strength of cubic BC2N using first-principles calculations. Our results reveal that, despite the large elastic parameters, compositiona…
Single particle dark field spectroscopy has been combined with high-resolution scanning electron and atomic force microscopy to study the scattering spectra of single gold/silica nanoshells. The plasmon resonant peak energies match those calculated by Mie theory based on the nanoshell geometry. The resonance line widt…
The synthesis, characterization, and catalytic properties of 1-3 nm-diameter bimetallic PdAu dendrimer-encapsulated catalysts are reported. Both alloy and core/shell PdAu nanoparticles were prepared. The catalytic hydrogenation of allyl alcohol was significantly enhanced in the presence of the alloy and core/shell PdA…
A free-standing nanoporous gold (NPG) membrane is made by dealloying commercially available white-gold leaf in nitric acid (see Figure). This porous material has an unusual combination of characteristics in that it is metallic with a continuous crystal lattice throughout the porous network, and has a pore size that is…
Abstract In recent decades, significant advances in drug‐delivery systems have enabled more effective drug administration. To deliver drugs to specific organs, a range of organic systems (e.g., micelles, liposomes, and polymeric nanoparticles) have been designed. They suffer from limitations, including poor thermal an…
A detailed study on the mechanism of band-to-band tunneling in carbon nanotube field-effect transistors (CNFETs) is presented. Through a dual-gated CNFET structure tunneling currents from the valence into the conduction band and vice versa can be enabled or disabled by changing the gate potential. Different from a con…