210 research outputs found
The impact of undergraduate degrees on early-career earnings
This report uses the new Longitudinal Educational Outcomes (LEO) administrative dataset to provide the latest estimates of the impact of Higher Education (HE) on individualsā early-career earnings after accounting for individualsā pre-university characteristics. This will provide vital evidence for prospective students choosing whether, where and what to study at university
How much does degree choice matter?
We use a large and novel administrative dataset to investigate returns to different university ādegreesā (subject-institution combinations) in the United Kingdom. Conditioning on a rich set of background characteristics, we find substantial variation in returns across degrees with similar selectivity levels, suggesting studentsā degree choices matter a lot for later-life earnings. Returns increase with university selectivity much more at the top of the selectivity distribution than further down, and much more for some subjects than others. Returns are poorly correlated with observable degree characteristics other than selectivity, which could have important implications for student choices and the incentives of universities
Analysis of the Transport Process Providing Spin Injection through an Fe/AlGaAs Schottky Barrier
Electron spin polarizations of 32% are obtained in a GaAs quantum well via
electrical injection through a reverse-biased Fe/AlGaAs Schottky contact. An
analysis of the transport data using the Rowell criteria demonstrates that
single step tunneling is the dominant transport mechanism. The current-voltage
data show a clear zero-bias anomaly and phonon signatures corresponding to the
GaAs-like and AlAs-like longitudinal-optical phonon modes of the AlGaAs
barrier, providing further evidence for tunneling. These results provide
experimental confirmation of several theoretical analyses indicating that
tunneling enables significant spin injection from a metal into a semiconductor.Comment: 4 pages, 4 figures, submitted to AP
Electrical Spin Pumping of Quantum Dots at Room Temperature
We report electrical control of the spin polarization of InAs/GaAs
self-assembled quantum dots (QDs) at room temperature. This is achieved by
electrical injection of spin-polarized electrons from an Fe Schottky contact.
The circular polarization of the QD electroluminescence shows that a 5%
electron spin polarization is obtained in the InAs QDs at 300 K, which is
remarkably insensitive to temperature. This is attributed to suppression of the
spin relaxation mechanisms in the QDs due to reduced dimensionality. These
results demonstrate that practical regimes of spin-based operation are clearly
attainable in solid state semiconductor devices.Comment: 4 figures, accepted by Appl. Phys. Let
Ultra-fast searching assists in evaluating sub-ppm mass accuracy enhancement in U-HPLC/Orbitrap MS data
A strategy, detailed methodology description and software are given with which the mass accuracy of U-HPLC-Orbitrap data (resolving power 50,000 FWHM) can be enhanced by an order of magnitude to sub-ppm levels. After mass accuracy enhancement all 211 reference masses have mass errors within 0.5Ā ppm; only 14 of these are outside the 0.2Ā ppm error margin. Further demonstration of mass accuracy enhancement is shown on a pre-concentrated urine sample in which evidence for 89 (342 ions) potential hydroxylated and glucuronated DHEA-metabolites is found. Although most DHEA metabolites have low-intensity mass signals, only 11 out of 342 are outside the Ā±1Ā ppm error envelop; 272 mass signals have errors below 0.5Ā ppm (142 below 0.2Ā ppm). The methodology consists of: (a) a multiple internal lock correction (here ten masses; no identity of internal lock masses is required) to avoid suppression problems of a single internal lock mass as well as to increase lock precision, (b) a multiple external mass correction (here 211 masses) to correct for calibration errors, (c) intensity dependant mass correction, (d) file averaging. The strategy is supported by ultra-fast file searching of baseline corrected, noise-reduced metAlign output. The output and efficiency of ultra-fast searching is essential in obtaining the required information to visualize the distribution of mass errors and isotope ratio deviations as a function of mass and intensity
Heteroepitaxial growth of ferromagnetic MnSb(0001) films on Ge/Si(111) virtual substrates
Molecular beam epitaxial growth of ferromagnetic MnSb(0001) has been achieved on high quality, fully relaxed Ge(111)/Si(111) virtual substrates grown by reduced pressure chemical vapor deposition. The epilayers were characterized using reflection high energy electron diffraction, synchrotron hard X-ray diffraction, X-ray photoemission spectroscopy, and magnetometry. The surface reconstructions, magnetic properties, crystalline quality, and strain relaxation behavior of the MnSb films are similar to those of MnSb grown on GaAs(111). In contrast to GaAs substrates, segregation of substrate atoms through the MnSb film does not occur, and alternative polymorphs of MnSb are absent
The integration of process planning and machine loading in small batch part manufacturing
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