We have determined locations for the donor and acceptor levels of muonium in six semiconductor materials (Si, Ge, GaAs, GaP, ZnSe, and 6H-SiC) as a test of defect-level pinning for hydrogen. Within theoretical band alignments, our results indicate a common energy for the equilibrium charge-transition level Mu(+/-) to within experimental uncertainties. However, this is nearly 0.5 eV higher than the energy at which the equivalent level for hydrogen was predicted to be pinned. Corrections for zero-point energy account for only about 10% of this difference. We also report experimental results for the (negative-U) difference between donor and acceptor levels for Mu to be compared with calculated values for H impurities in the same materials. 相似文献
For targeted proteomics to be broadly adopted in biological laboratories as a routine experimental protocol, wet-bench biologists must be able to approach selected reaction monitoring (SRM) and parallel reaction monitoring (PRM) assay design in the same way they approach biological experimental design. Most often, biological hypotheses are envisioned in a set of protein interactions, networks, and pathways. We present a plugin for the popular Skyline tool that presents public mass spectrometry data in a pathway-centric view to assist users in browsing available data and determining how to design quantitative experiments. Selected proteins and their underlying mass spectra are imported to Skyline for further assay design (transition selection). The same plugin can be used for hypothesis-driven data-independent acquisition (DIA) data analysis, again utilizing the pathway view to help narrow down the set of proteins that will be investigated. The plugin is backed by the Pacific Northwest National Laboratory (PNNL) Biodiversity Library, a corpus of 3 million peptides from >100 organisms, and the draft human proteome. Users can upload personal data to the plugin to use the pathway navigation prior to importing their own data into Skyline.
A systematic investigation of five sherds from the Celtic oppidum of Manching by refiring in different atmospheres is presented. The data are part of an extended and general study of Celtic ceramics in early Europe. 相似文献
Datailed muon level-crossing resonance measurements of Mu1 and Mu11 centres in single crystals of CuCl are presented. The hyperfine and nuclear hyperfine parameters of the closest two shells
of nuclei are remarkably similar for the two centres, indicating that both are located at the same tetrahedral interstitial
site with four Cu nearest neighbours and six Cl next-nearest neighbours. About 30% of the total unpaired-electron spin density
is located on the muon, about 60% on the four nearest neighbours and the rest on the six next-nearest neighbours, with nothing
observable for any other shell. 相似文献
Results of Muon-Spin-Relaxation (μSR) experiments on well-defined single crystals of corundum (α-Al2O3) are reported. Major issue in this study is the controversy of muon bonding or muonium formation in insulators. Transverse,
zero-field and longitudinal field measurements were performed as a function of temperature or applied field. The obtained
results indicate that muon-oxygen bonding occurs in α-Al2O3, having (at least) two (μO) states as found earlier for α-Fe2O3. The occurrence of a 10% missing fraction suggests Mu states, although Mu was not observed in our measurements. These results
and their implications are discussed in light of other experimental μSR studies on insulating oxides and the above-mentioned
controversy. 相似文献
A useful guide to detecting quadrupole level crossing resonance (QLCR) spectra is to search in the vicinity of BE\cdot(\gamman/\gamma_μ), where BE is the onset magnetic field for the decoupling of the quadrupole interaction, as seen in muon spin rotation linewidths. More
detailed predictions of the positions and intensities of the resonances require numerical simulations taking account of the
local geometry of the muon site. We present such simulations for muons adjacent to nuclei of spin 9/2 and demonstrate a pronounced
dependence on the anisotropy of the quadrupole coupling tensor. Simulations for the specific cases of muons located at the
octahedral and tetrahedral interstices in niobium metal are compared with the experimentally detected spectrum in a polycrystalline
sample.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献