2,205 research outputs found

    Deep Level Transient Spectroscopy in Quantum Dot Characterization

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    Deep level transient spectroscopy (DLTS) for investigating electronic properties of self-assembled InAs/GaAs quantum dots (QDs) is described in an approach, where experimental and theoretical DLTS data are compared in a temperature-voltage representation. From such comparative studies, the main mechanisms of electron escape from QD-related levels in tunneling and more complex thermal processes are discovered. Measurement conditions for proper characterization of the levels by identifying thermal and tunneling processes are discussed in terms of the complexity resulting from the features of self-assembled QDs and multiple paths for electron escape

    The In-group and Out-groups of the British National Party and UK Independence Party: A corpus-based Critical Discourse Analysis

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    The purpose of this paper is to determine to what degree there are textual and conceptual similarities between the British National Party’s (BNP) and UK Independence Party’s (UKIP) construction of in-groups and out-groups. The focus is on the two discursive strategies nomination (attribution of word form) and predication (attribution of quality). For the present study I adopt the Discourse-Historical Approach to Critical Discourse Analysis, which offers a broad sociologic understanding of linguistic phenomena through historical contextualization. The data consist of a corpus containing news articles and policy documents from official BNP and UKIP outputs. The in-group analysis shows that both parties have gained in confidence between the 2005 and 2010 general elections, which is mirrored in their choice of party name as preferred form of self-representation. When claiming uniqueness, both parties mix ideological themes with concrete policies, but UKIP claims ownership of more banal policies. While the BNP and UKIP criticize each other, the main recipients of their criticism are the establishment parties. Both parties feel the need to distance themselves from accusations of racism; the BNP in particular. The out-group analysis shows that both parties frequently discuss immigration and refer to immigrants using the same word forms, although UKIP’s use is more consistent with internationally agreed definitions. Both parties construct immigration as unstoppable forces, e.g. by using water metaphors. References to country of origin are also frequent; UKIP emphasizes Eastern European immigration while the BNP highlights immigration from the Third World. Overall, the analysis shows that both parties use language extensively to distinguish between in-groups and out-groups, but that UKIP’s parameters are more fine-tuned

    Control System for CRYRING

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    The Role of Attorney Fee Shifting in Public Interest Litigation

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    BACKGROUND: Brain tissue segmentation of white matter (WM), grey matter (GM), and cerebrospinal fluid (CSF) are important in neuroradiological applications. Quantitative Mri (qMRI) allows segmentation based on physical tissue properties, and the dependencies on MR scanner settings are removed. Brain tissue groups into clusters in the three dimensional space formed by the qMRI parameters R1, R2 and PD, and partial volume voxels are intermediate in this space. The qMRI parameters, however, depend on the main magnetic field strength. Therefore, longitudinal studies can be seriously limited by system upgrades. The aim of this work was to apply one recently described brain tissue segmentation method, based on qMRI, at both 1.5 T and 3.0 T field strengths, and to investigate similarities and differences. METHODS: In vivo qMRI measurements were performed on 10 healthy subjects using both 1.5 T and 3.0 T MR scanners. The brain tissue segmentation method was applied for both 1.5 T and 3.0 T and volumes of WM, GM, CSF and brain parenchymal fraction (BPF) were calculated on both field strengths. Repeatability was calculated for each scanner and a General Linear Model was used to examine the effect of field strength. Voxel-wise t-tests were also performed to evaluate regional differences. RESULTS: Statistically significant differences were found between 1.5 T and 3.0 T for WM, GM, CSF and BPF (p<0.001). Analyses of main effects showed that WM was underestimated, while GM and CSF were overestimated on 1.5 T compared to 3.0 T. The mean differences between 1.5 T and 3.0 T were -66 mL WM, 40 mL GM, 29 mL CSF and -1.99% BPF. Voxel-wise t-tests revealed regional differences of WM and GM in deep brain structures, cerebellum and brain stem. CONCLUSIONS: Most of the brain was identically classified at the two field strengths, although some regional differences were observed

    Photoemission yield and the electron escape depth determination in metal-oxide-semiconductor structures on N+-type and P+-type silicon substrates

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    This article gives a quantitative analysis of electron photoemission yield from N+-type and P+-type substrates of MOS structures. Based on this analysis, a method is presented to estimate both the scattering length, l, of electrons in the image force potential well and of photoelectron escape depth, x(esc), from the semiconductor substrate. This method was used to estimate the scattering length and the escape depth from the substrates of Al-SiO2-Si (N+-type and P+-type) structures. It was found that for N+-type substrate structures the scattering in the image force potential well has a dominating influence on the photoemission yield while for P+-type substrate structures both the scattering in the image force potential well and the photoemission from the subsurface regions of the photoemitter play important roles. It was found that the scattering length in the image force potential well was equal to l = 6.7-6.9 nm for structures on both N+ and P+ substrates, produced in the same processing conditions. For structures on P+ substrates, the escape depth was found to be equal to x(esc) = 8-9 nm. The scattering length, l, determined in this study is considerably larger than the one reported previously (l = 3.4 nm) for similar MOS structures. The escape depth x(esc) determined in this study is also considerably larger than the escape depth determined previously (x(esc) = 1.2-2.5 nm) for the external photoemission from uncovered silicon surfaces into vacuum

    Prevalence and Prognostic Significance of Asymptomatic Peripheral Arterial Disease in 68-year-old Men with Diabetes. Results from the Population Study 'Men Born in 1914' from Malmo, Sweden.

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    AbstractObjectiveTo assess the prevalence of asymptomatic peripheral arterial disease (PAD) in older men with diabetes and to compare the incidence of cardiac events and deaths in diabetic and non-diabetic men with abnormal and normal systolic ankle–brachial pressure index, respectively.Research design and methodsPopulation-based cohort of 68-year-old men (n=474). Diabetes was defined as history of diabetes or a fasting blood glucose ≥6.1mmol/l. PAD was defined as an ankle–brachial pressure index (ABI) <0.9 in either leg. Fourteen-year mortality and cardiac event rates were based on record linkage with regional and national registers.ResultsThe prevalence of PAD in men with and without diabetes was 29 and 12%, respectively (p=0.003). The incidence of cardiac events was 22.9/1000 person years in men free from both diabetes and PAD. In the absence of an abnormal pressure index, diabetes was associated with an event rate of 28.4 (p=0.469). In the presence of an abnormal index the incidence was 102 (p<0.001). This pattern remained in the multivariate analysis when other atherosclerotic risk factors were taken into account. Cardiovascular mortality rates similarly differed substantially between diabetic men with and without PAD.ConclusionsA fasting blood glucose value above 6.1mmol/l even in the absence of symptoms indicating diabetes was associated by an increased prevalence of asymptomatic PAD. The cardiovascular risk in diabetes varied widely between men with and without abnormal ankle–brachial pressure index

    High-repetition-rate combustion thermometry with two-line atomic fluorescence excited by diode lasers

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    We report on kilohertz-repetition-rate flame temperature measurements performed using blue diode lasers. Two-line atomic fluorescence was performed by using diode lasers emitting at around 410 and 451 nm to probe seeded atomic indium. At a repetition rate of 3.5 kHz our technique offers a precision of 1.5% at 2000 K in laminar methane/air flames. The spatial resolution is better than 150 mu m, while the setup is compact and easy to operate, at much lower cost than alternative techniques. By modeling the spectral overlap between the locked laser and the probed indium lines we avoid the need for any calibration of the measurements. We demonstrate the capability of the technique for time-resolved measurements in an acoustically perturbed flame. The technique is applicable in flames with a wide range of compositions including sooting flames
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