Materials Literature
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Giant metal cages: Mesoporous Pt particles, with mesocages connected closely in three dimensions (see picture), are prepared by an electrodeposition process through soft templating from lyotropic liquid crystals of diblock copolymers. The size of the mesocages is the largest (about 15 nm) reported in mesoporous metals…
We demonstrate, for the first time, that organic−inorganic hybrid hollow nanospheres with controllable size (12−20 nm) and shell thickness (4−7 nm) can be successfully synthesized through the condensation of 1,2-bis(trimethoxysilyl)ethane (BTME) around an inorganic-electrolyte-stabilized F127 micelle under a mild buff…
Molecular dynamics (MD) simulations were carried out to study the stress−strain diagrams of crystalline and amorphous silica under different nonequilibrium conditions. The responses of a tensile load were recorded in two cases. In one case, the system was not allowed to relax along the transverse direction (null Poiss…
The initial stages of water condensation, approximately 6 molecular layers, on two oxide surfaces, Cu 2 O and Al 2 O 3, have been investigated by using ambient pressure X-ray photoelectron spectroscopy at relative humidity values (RH) from 0 to >90%. Water adsorbs first dissociatively on oxygen vacancies producing ads…
By means of ab initio calculations within the density functional theory, we have found that ${\text{B}}_{80}$ fullerenes can condense to form stable face-centered-cubic (fcc) solids. It is shown that when forming a crystal, ${\text{B}}_{80}$ cages are geometrically distorted, the ${\text{I}}_{h}$ symmetry is lowered t…
The variation of metallic particle size and sample porosity significantly alters the dynamic mechanical properties of high density granular composites processed using a cold isostatically pressed mixture of polytetrafluoroethylene (PTFE), aluminum (Al) and tungsten (W) powders. Quasi-static and dynamic experiments are…
The stability mechanism of cuboctahedral clusters in nonstoichiometric uranium dioxide is investigated by first-principles LSDA+U method. Calculations reveal that the structural stability is inherited from U6O12 molecular cluster whereas the energy gain through occupying its center with an additional oxygen makes the…
Local and semilocal density-functional approximations for the exchange-correlation energy fail badly in the zero-thickness limit of a quasi-two-dimensional electron gas, where the density variation is rapid almost everywhere. Here we show that a fully nonlocal fifth-rung functional, the inhomogeneous Singwi-Tosi-Land-…
We have studied the interplay of a giant spin-orbit splitting and of quantum confinement in artificial Bi-Ag-Si trilayer structures. Angle-resolved photoelectron spectroscopy (ARPES) reveals the formation of a complex spin-dependent gap structure, which can be tuned by varying the thickness of the Ag buffer layer. Thi…
A negative-positive-negative switching behavior of magnetoresistance (MR) with temperature is observed in a ferromagnetic shape memory alloy ${\text{Ni}}_{1.75}{\text{Mn}}_{1.25}\text{Ga}$. In the austenitic phase between 300 and 120 K, MR is negative due to $s\text{\ensuremath{-}}d$ scattering. Curiously, below 120 K…
In photosynthesis, sunlight energy is converted into a chemical potential by an electron transfer sequence that is started by an excited state and ultimately yields a long-lived charge-separated state. This process can be reproduced by carefully designed multicomponent artificial arrays of three or more components, an…
Abstract This paper presents results from lean CO/H 2 /O 2 /NO x oxidation experiments conducted at 20–100 bar and 600–900 K. The experiments were carried out in a new high‐pressure laminar flow reactor designed to conduct well‐defined experimental investigations of homogeneous gas phase chemistry at pressures and tem…
We have fabricated graphene devices with a top gate separated from the graphene layer by an air gap-a design which does not decrease the mobility of charge carriers under the gate. This gate is used to realize p-n-p structures where the conducting properties of chiral carriers are studied. The band profile of the stru…
Applying a quasiclassical equation to carriers in graphene, we found a way how to distinguish between samples with the domination of short- and long-range scatterers from the conductivity measurements. The model proposed explains recent transport experiments with chemically doped as well as suspended graphene.
SiO2/V2O5/TiO2 catalysts were synthesized for removing elemental mercury (Hg0) from simulated coal-combustion flue gas. Experiments were carried out in fixed-bed reactors using both pellet and powder catalysts. In contrast to the SiO2-TiO2 composites developed in previous studies, the V2O5 based catalysts do not need…
While the activity of the SMAD powders is lower than that of pure silver nitrate, it has the ability to kill bacteria very effectively and over long periods of time.
A coarse grain model and a Monte Carlo sampling formalism are proposed for simulations of self-assembly in block copolymer melts and nanoparticle−copolymer composites. Our approach relies on a particle-based representation of the system, it does not invoke a saddle point approximation, and it permits treatment of larg…
Abstract We review the performance of various nanoscaled structures needed to support the propagation of the surface plasmons responsible for surface‐enhanced Raman scattering (SERS), and assess the potential for the optimisation of the compromise between enhancement and reproducibility that they provide, and hence th…
The impressively low friction and wear of diamond in humid environments is debated to originate from either the stability of the passivated diamond surface or sliding-induced graphitization/rehybridization of carbon. We find ultralow friction and wear for ultrananocrystalline diamond surfaces even in dry environments,…
Monodisperse rhodium (Rh) and platinum (Pt) nanoparticles as small as approximately 1 nm were synthesized within a fourth generation polyaminoamide (PAMAM) dendrimer, a hyperbranched polymer, in aqueous solution and immobilized by depositing onto a high-surface-area SBA-15 mesoporous support. X-ray photoelectron spect…