85 research outputs found

    Understanding of sub-band gap absorption of femtosecond-laser sulfur hyperdoped silicon using synchrotron-based techniques

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    [[abstract]]The correlation between sub-band gap absorption and the chemical states and electronic and atomic structures of S-hyperdoped Si have been extensively studied, using synchrotron-based x-ray photoelectron spectroscopy (XPS), x-ray absorption near-edge spectroscopy (XANES), extended x-ray absorption fine structure (EXAFS), valence-band photoemission spectroscopy (VB-PES) and first-principles calculation. S 2p XPS spectra reveal that the S-hyperdoped Si with the greatest (~87%) sub-band gap absorption contains the highest concentration of S2− (monosulfide) species. Annealing S-hyperdoped Si reduces the sub-band gap absorptance and the concentration of S2− species, but significantly increases the concentration of larger S clusters [polysulfides (Sn2−, n > 2)]. The Si K-edge XANES spectra show that S hyperdoping in Si increases (decreased) the occupied (unoccupied) electronic density of states at/above the conduction-band-minimum. VB-PES spectra evidently reveal that the S-dopants not only form an impurity band deep within the band gap, giving rise to the sub-band gap absorption, but also cause the insulator-to-metal transition in S-hyperdoped Si samples. Based on the experimental results and the calculations by density functional theory, the chemical state of the S species and the formation of the S-dopant states in the band gap of Si are critical in determining the sub-band gap absorptance of hyperdoped Si samples.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[ispeerreviewed]]Y[[booktype]]電子版[[countrycodes]]GB

    Apples and Dragon Fruits: The Determinants of Aid and Other Forms of State Financing from China to Africa

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    (How) do medical students regulate their emotions?

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    BACKGROUND: Medical training can be a challenging and emotionally intense period for medical students. However the emotions experienced by medical students in the face of challenging situations and the emotion regulation strategies they use remains relatively unexplored. The aim of the present study was to explore the emotions elicited by memorable incidents reported by medical students and the associated emotion regulation strategies. METHODS: Peer interviewing was used to collect medical students’ memorable incidents. Medical students at both preclinical and clinical stage of medical school were eligible to participate. In total 104 medical students provided memorable incidents. Only 54 narratives included references to emotions and emotion regulation and thus were further analyzed. RESULTS: The narratives of 47 clinical and 7 preclinical students were further analyzed for their references to emotions and emotion regulation strategies. Forty seven out of 54 incidents described a negative incident associated with negative emotions. The most frequently mentioned emotion was shock and surprise followed by feelings of embarrassment, sadness, anger and tension or anxiety. The most frequent reaction was inaction often associated with emotion regulation strategies such as distraction, focusing on a task, suppression of emotions and reappraisal. When students witnessed mistreatment or disrespect exhibited towards patients, the regulation strategy used involved focusing and comforting the patient. CONCLUSIONS: The present study sheds light on the strategies medical students use to deal with intense negative emotions. The vast majority reported inaction in the face of a challenging situation and the use of more subtle strategies to deal with the emotional impact of the incident. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12909-016-0832-9) contains supplementary material, which is available to authorized users

    Aid on Demand: African Leaders and the Geography of China's Foreign Assistance

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    Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

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    Measurement of electron antineutrino oscillation based on 1230 days of operation of the Daya Bay experiment

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    Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

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    Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay

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    Independent measure of the neutrino mixing angle θ13 via neutron capture on hydrogen at Daya Bay

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    The muon system of the Daya Bay Reactor antineutrino experiment

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