Nanoscale engineering of gold particles in 18th century Böttger lusters and glazes.

SignificanceThe exploration of gold-based colorants in glass and glazes led Nobel Laureate Richard Zsigmondy to the study of colloids, and to the development, with Henry Siedentopf, of the earliest microscopes capable of resolving such small length scales. Zsigmondy's studies were preceded by alchemical investigations starting in the 17th century that yielded the gold-based Purple of Cassius, and experiments in the early 18th century resulting in an unusual purple iridescent porcelain overglaze, called Böttger luster, at the Meissen Manufactory. We discuss the first nano-scale characterization of Böttger luster, its successful replication, and propose an explanation for its optical properties based on the physics of scattering and interference of nanoparticle arrays.

Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis.

We report the discovery in Lake Cuitzeo in central Mexico of a black, carbon-rich, lacustrine layer, containing nanodiamonds, microspherules, and other unusual materials that date to the early Younger Dryas and are interpreted to result from an extraterrestrial impact. These proxies were found in a 27-m-long core as part of an interdisciplinary effort to extract a paleoclimate record back through the previous interglacial. Our attention focused early on an anomalous, 10-cm-thick, carbon-rich layer at a depth of 2.8 m that dates to 12.9 ka and coincides with a suite of anomalous coeval environmental and biotic changes independently recognized in other regional lake sequences. Collectively, these changes have produced the most distinctive boundary layer in the late Quaternary record. This layer contains a diverse, abundant assemblage of impact-related markers, including nanodiamonds, carbon spherules, and magnetic spherules with rapid melting/quenching textures, all reaching synchronous peaks immediately beneath a layer containing the largest peak of charcoal in the core. Analyses by multiple methods demonstrate the presence of three allotropes of nanodiamond: n-diamond, i-carbon, and hexagonal nanodiamond (lonsdaleite), in order of estimated relative abundance. This nanodiamond-rich layer is consistent with the Younger Dryas boundary layer found at numerous sites across North America, Greenland, and Western Europe. We have examined multiple hypotheses to account for these observations and find the evidence cannot be explained by any known terrestrial mechanism. It is, however, consistent with the Younger Dryas boundary impact hypothesis postulating a major extraterrestrial impact involving multiple airburst(s) and and/or ground impact(s) at 12.9 ka.

Nanoscale structure, composition, and charge transport analysis of transparent conducting oxide nanowires written by focused ion beam implantation.

Realizing optically transparent functional circuitry continues to fuel scientific and technological interest in transparent conducting oxides (TCOs). However, precise means for creating transparent interconnects for device-to-device integration has remained elusive. Here we report on the chemical, microstructural, and electronic properties of transparent conducting oxide nanowires (Ga-doped In(2)O(3)) created by direct-write focused ion beam (Ga(+)) implantation within an insulating oxide substrate (In(2)O(3)). First, methodology for preparing TEM-ready samples is presented that enables detailed TEM-based analysis of individual nanowires. Differences in diffraction features between doped and undoped oxide regions, accompanied by RTA results, support a model in which oxygen vacancies and amorphization comprise the predominant doping/carrier creation mechanism. The same isolated nanowires are then subjected to chemical profiling, providing quantitative information on the lateral Ga doping dimensions, which are in good agreement with conductive AFM images. Furthermore, spatially selective nanoscale EELS spectroscopy provides additional evidence for changes in the oxygen site chemical environment in the FIB-processed/doped In(2)O(3), and for negligible changes in the surrounding non-FIB-processed/undoped oxide. The nanowires exhibit ohmic electrical behavior and with an average estimated conductivity of 1600-3600 S cm(-1), similar to macroscale Ga-doped In(2)O(3) films grown by conventional processes.

Defect and interfacial structure of heteroepitaxial Fe3O4/BaTiO3 bilayers.

The defect and interfacial structure in a Fe3O4/BaTiO3 heteroepitaxial bilayer was investigated by scanning transmission electron microscopy. The results show that the Fe3O4 film grew epitaxially on BaTiO3. The orientation relationship between Fe3O4, BaTiO3 and MgO is [100]Fe3O4//[100]BaTi3O//[100]MgO and (010)Fe3O4//(010)BaTiO3//(010)MgO. An initial interfacial nucleation layer was formed that partially accommodated the lattice mismatch strain between BaTiO3 and MgO. This investigation indicates that the formation of this buffer layer provides a high-quality BaTiO3 surface for subsequent Fe3O4 growth, resulting in a semicoherent interface. The Fe3O4 surface is nearly atomically abrupt (roughness Rrms = 0.78 nm). The Fe3O4 film exhibits magnetic domains with a diameter in the range of 0.4-2 microm.

[Determination of 8 elements in Elaeagnus mollis by AAS].

Eight kinds of trace elements of Elaeagnus mollis were determinated with flame atomic absorption spectrophotometry method. The result shows that there is evident difference of the trace elements in different organs and growing stages. The trace element is plentiful in this kind of plant, specially in root, leaf and seed.

[Analysis of Ca, Mg, Fe, Mn, Cu and Zn in algae].

In this paper, we used flame atomic absorption spectrophotometry to determine the contents of Ca, Mg, Fe, Mn, Cu and Zn in 7 species of algae. The results showed that there were relatively rich Ca, Mg, Fe, Mn, Cu and Zn in the algae. The useful data were provided for algae as resource to be utilized.