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。
Giant negative thermal expansion is achieved in antiperovskite manganese nitrides when the sharp volume change associated with magnetic ordering is broadened by substitution. In this Letter, we address the unique role of the ''magic" element, Ge, for such broadening in Mn3Cu1-xGexN. We present evidence for a local lat…
A facile and reproducible approach for preparing Au-CdS core−shell nanocrystals with controllable shell thickness was successfully developed. A depression of the photoluminescence emission of CdS was observed in Au-CdS nanocrystals, demonstrating the photoinduced charge separation and the effective electron transfer f…
The dynamical, dielectric, and elastic properties of GeTe, a ferroelectric material in its low-temperature rhombohedral phase, have been investigated using first-principles density functional theory. We report the electronic energy bands, phonon-dispersion curves, electronic and low-frequency dielectric tensors, infra…
The perovskite ${\mathrm{SrTiO}}_{3}$ becomes metallic with 0.03% to 0.1% Nb substitution on the Ti site, while ${\mathrm{BaTiO}}_{3}$ remains insulating above 10% Nb substitution. Given the nearly identical structure and electron counts of the two materials, the distinct ground states for low substitution have been a…
A quantum Markovian activated atom-surface diffusion model with interacting adsorbates is proposed for the intermediate scattering function, which is shown to be complex-valued and factorizable into a classical-like and a quantum-mechanical factor. Applications to the diffusion of Na atoms on flat (weakly corrugated)…
The development of the crystallinity and of the crystallographic orientation of isotactic polypropylene (iPP) during rolling deformation and subsequent heat treatment is studied. The experiments are conducted by using X-ray diffraction with an area detector. The evolution of crystallographic orientation is tracked by…
As molecular dynamics is increasingly used to characterize non-crystalline materials, it is crucial to verify that the numerical model is accurate enough, consistent with experimental data and can be used to extract various characteristics of disordered systems. In most cases the only derived property used to test the…
The kinetics of hydrogen absorption by magnesium bulk is affected by two main activated processes: the dissociation of the H$_2$ molecule and the diffusion of atomic H into the bulk. In order to have fast absorption kinetics both activated processed need to have a low barrier. Here we report a systematic ab-initio den…
Insight into the nature of transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions is obtainable from a number of surface spectroscopic techniques. Carrying out these investigations under actual reaction conditions is preferred but remains challenging, especia…
We have developed a novel separation method of metallic and semiconducting single-wall carbon nanotubes (SWCNTs) using agarose gel electrophoresis. When the SWCNTs were isolated with sodium dodecyl sulfate (SDS) and embedded in agarose gel, only the metallic SWCNTs separated from the starting gel by an electric field.…
Quantum dots (QDs) are increasingly being used for electronics, solar energy generation, and medical imaging applications. Most QDs consist of a heavy metal core/shell coated with amphiphilic organics that stabilize the nanoparticles and allow conjugation with biological molecules. In this study, QDs were evaluated fo…
We synthesized various hollow oxide nanoparticles from as-prepared MnO and iron oxide nanocrystals. Heating metal oxide nanocrystals dispersed in technical grade trioctylphosphine oxide (TOPO) at 300 degrees C for hours yielded hollow nanoparticles retaining the size and shape uniformity of the original nanocrystals.…
We show that a number of model liquids at fixed volume exhibit strong correlations between equilibrium fluctuations of the configurational parts of (instantaneous) pressure and energy. We present detailed results for 13 systems, showing in which systems these correlations are significant. These include Lennard-Jones l…
The site-selective functionalization of mesoporous nanoparticles was achieved with a sequential co-condensation approach. Using this strategy, functional groups were completely dispersed inside the channels, concentrated in parts of the mesopores, or exclusively placed on the external surface of colloidal mesoporous s…
In the strontium iron-cobalt arsenides ${\mathrm{SrFe}}_{2\ensuremath{-}x}{\mathrm{Co}}_{x}{\mathrm{As}}_{2}$ ($0.2\ensuremath{\le}x\ensuremath{\le}0.4$) superconductivity with ${T}_{c}$ up to 20 K is observed in magnetic susceptibility, electrical resistivity, and specific heat data. This first observation of bulk su…
Strong red upconversion luminescence of rare-earth ions doped in nanocrystals is desirable for the biological/biomedical applications. In this paper, we describe the great enhancement of red upconversion emission (4F9/2 --> I15/2 transition of Er3+ ion) in NaYF4:Yb3+, Er3+ nanocrystals at low doping level, which is as…
The biodistribution and urinary excretion of different surface-modified silica nanoparticles (SiNPs) in mice were investigated in situ using an in vivo optical imaging system. Three types of surface-modified SiNPs, including OH-SiNPs, COOH-SiNPs, and PEG-SiNPs with a size of approximately 45 nm, have been prepared wit…
We study the pairing symmetry of a two-orbital ${J}_{1}\mathrm{\text{\ensuremath{-}}}{J}_{2}$ model for FeAs layers in oxypnictides. We show that the mixture of an intraorbital unconventional ${s}_{{x}^{2}{y}^{2}}\ensuremath{\sim}\mathrm{cos}({k}_{x})\mathrm{cos}({k}_{y})$ pairing symmetry, which changes sign betwee…
We report the first successful application of an ordered bicontinuous gyroid semiconducting network in a hybrid bulk heterojunction solar cell. The freestanding gyroid network is fabricated by electrochemical deposition into the 10 nm wide voided channels of a self-assembled, selectively degradable block copolymer fil…
A novel single-walled carbon nanotube (SWNT)-based tumor-targeted drug delivery system (DDS) has been developed, which consists of a functionalized SWNT linked to tumor-targeting modules as well as prodrug modules. There are three key features of this nanoscale DDS: (a) use of functionalized SWNTs as a biocompatible p…