38,489 research outputs found

    Spin-injection Hall effect in a planar photovoltaic cell

    Full text link
    Successful incorporation of the spin degree of freedom in semiconductor technology requires the development of a new paradigm allowing for a scalable, non-destructive electrical detection of the spin-polarization of injected charge carriers as they propagate along the semiconducting channel. In this paper we report the observation of a spin-injection Hall effect (SIHE) which exploits the quantum-relativistic nature of spin-charge transport and which meets all these key requirements on the spin detection. The two-dimensional electron-hole gas photo-voltaic cell we designed to observe the SIHE allows us to develop a quantitative microscopic theory of the phenomenon and to demonstrate its direct application in optoelectronics. We report an experimental realization of a non-magnetic spin-photovoltaic effect via the SIHE, rendering our device an electrical polarimeter which directly converts the degree of circular polarization of light to a voltage signal.Comment: 14 pages, 4 figure

    High-Fidelity Archeointensity Results for the Late Neolithic Period From Central China

    Get PDF
    Archeomagnetism focuses on exploring high-resolution variations of the geomagnetic field over hundreds to thousands of years. In this study, we carried out a comprehensive study of chronology, absolute and relative paleointensity on a late Neolithic site in central China. Ages of the samples are constrained to be ~3,500–3,000 BCE, a period when available paleointensity data are sparse. We present a total of 64 high-fidelity absolute paleointensities, demonstrating the field varied quickly from ~55 to ~90 ZAm2 between ~3,500–3,000 BCE. Our results record a new archeomagnetic jerk around 3,300 BCE, which is probably non-dipolar origin. The new results provide robust constraints on global geomagnetic models. We calculated a revised Chinese archeointensity reference curve for future application. The variations of absolute and relative paleointensity versus depth show good consistency, reinforcing the reliability of our results. This new attempt of combining absolute and relative paleointenstiy provides a useful tool for future archeomagnetic research

    Phase-reference VLBI Observations of the Compact Steep-Spectrum Source 3C 138

    Full text link
    We investigate a phase-reference VLBI observation that was conducted at 15.4 GHz by fast switching VLBA antennas between the compact steep-spectrum radio source 3C 138 and the quasar PKS 0528+134 which are about 4∘^\circ away on the sky. By comparing the phase-reference mapping with the conventional hybrid mapping, we demonstrate the feasibility of high precision astrometric measurements for sources separated by 4∘^\circ. VLBI phase-reference mapping preserves the relative phase information, and thus provides an accurate relative position between 3C 138 and PKS 0528+134 of Δα=−9m46s.531000±0s.000003\Delta\alpha=-9^m46^s.531000\pm0^s.000003 and Δδ=3∘6′26′′.90311±0′′.00007\Delta\delta=3^\circ6^\prime26^{\prime\prime}.90311\pm0^{\prime\prime}.00007 (J2000.0) in right ascension and declination, respectively. This gives an improved position of the nucleus (component A) of 3C 138 in J2000.0 to be RA=05h21m9s.88574805^h 21^m 9^s.885748 and Dec=16∘38′22′′.0526116^\circ 38' 22''.05261 under the assumption that the position of calibrator PKS 0528+134 is correct. We further made a hybrid map by performing several iterations of CLEAN and self-calibration on the phase-referenced data with the phase-reference map as an input model for the first phase self-calibration. Compared with the hybrid map from the limited visibility data directly obtained from fringe fitting 3C 138 data, this map has a similar dynamic range, but a higher angular resolution. Therefore, phase-reference technique is not only a means of phase connection, but also a means of increasing phase coherence time allowing self-calibration technique to be applied to much weaker sources.Comment: 9 pages plus 2 figures, accepted by PASJ (Vol.58 No.6

    Better together? A hospitality case for umbrella branding

    Get PDF
    While the topic of ‘umbrella branding’ (UB) strategies for manufacturers' products in the business-to business literature has received attention, much less has been written about UB strategies in the hospitality industry. With the aid of a theoretical framework this paper explores three types of behavioural characteristics: alliance attribute; communication behaviour; and alliance management to examine cost and service benefits for alliance success within one umbrella organisation in the German hospitality industry. The theoretical framework of the paper built on the model of Vanpoucke and Vereecke (2010), incorporating a top management perspective to test and extend an umbrella brand. Design/methodology: Semi-structured interviews with a sample of senior managers were undertaken in Germany at the headquarters of Ringhotels v.E. Content analysis of the data collected was implemented to increase understanding of the research phenomenon with regard to relationships and the conceptual framework applied. The results were presented in the tables with discussions about the qualitative research Findings: The results of the study showed that behavioural characteristics played a significant role in explaining overall alliance success on cost and service benefits. A good level of quality presented in Ringhotels’ services, marketing, risk and coordination were found to be a better predictor of success when absence of management and lack of trust hampered good performance. Originality/Contribution: The study offers insights into the management of relationships within Ringhotels v.E. and how these can be better managed. The main contribution of the work fills in a gap currently existing in the literature about umbrella branding within the hospitality industry

    The effect of parental opportunism, IJV's autonomy and tacit knowledge on IJV instability: A comparison of multi-variate regression and fuzzy-set qualitative comparative analysis

    Get PDF
    This study uses an agency theory perspective to examine how the factors that influence principal (IJV parents) and agent (IJV) relationship may affect IJV instability in China. The study proposes a framework that bridges knowledge-based theory (of tacit knowledge) and agency theory (of parental opportunism) by incorporating reactance theory (of autonomy). By comparing the empirical results of fuzzy-set qualitative comparative analysis (fsQCA) and multiple regression analysis, using a sample of 203 Chinese-foreign IJVs, the study add further evidence to growing methodological consideration regarding complexity theory. The results from multiple regressions show that parental opportunism and IJV’s autonomy has a positive effect on IJV’s instability, and that the interaction of autonomy and tacit knowledge moderates the effect of parental opportunism on IJV instability. However, fsQCA uncovers more causal paths than findings from multiple regression analysis

    P-Selectivity, Immunity, and the Power of One Bit

    Full text link
    We prove that P-sel, the class of all P-selective sets, is EXP-immune, but is not EXP/1-immune. That is, we prove that some infinite P-selective set has no infinite EXP-time subset, but we also prove that every infinite P-selective set has some infinite subset in EXP/1. Informally put, the immunity of P-sel is so fragile that it is pierced by a single bit of information. The above claims follow from broader results that we obtain about the immunity of the P-selective sets. In particular, we prove that for every recursive function f, P-sel is DTIME(f)-immune. Yet we also prove that P-sel is not \Pi_2^p/1-immune

    Interest rate regulation, earnings transparency and capital structure: evidence from Chinese listed companies, 2003-2015

    Get PDF
    We use samples from Chinese listed companies to investigate the effects of interest rate deregulation and earnings transparency on company’s capital structure in China over the period of 2003-2015. In particular, we study the link between state-owned enterprises (SOEs), economic growth targets, and marketization in China's unique institutional context. The results show earnings transparency increases firm leverage and the additional tests suggest that such an effect takes place via a mechanism by reducing the cost of debt finance. However, information transparency could moderate the effects of interest rate deregulation on corporate capital structure. In addition, it finds that SOEs are less sensitive towards the changes of interest rates in China because lending to SOEs is policy-oriented and lacks of market evaluation of business risk. Government control is conducive to enhancing the transparency of the whole industry, however, market-oriented reform is conducive to enhancing the transparency of the company's own information. The results are robust to endogeneity tests and a variety of variable and model specifications. Lastly, we find that information transparency has little impact on equity financing because of IPO and SEO strictly controlled by the Chinese government. These findings are important for management and policy implications. The paper makes contribution to the relationship between earnings disclosure quality and capital structure in the Chinese unique institutional context, such as taking the progressive interest rate reform, SOES, different economic growth target and different marketization level in each province of China. We suggest that investors will pay more attention to the company's own unique information transparency in the provinces with high degree of marketization. As a potential direction for future research, we will investigate how the earnings transparency has impact on capital structure, and how such impact would depend on the transparency of specific business, the cap of foreign shareholding and the convenience of investment

    Inelastic X-Ray Scattering Study of Exciton Properties in an Organic Molecular crystal

    Full text link
    Excitons in a complex organic molecular crystal were studied by inelastic x-ray scattering (IXS) for the first time. The dynamic dielectric response function is measured over a large momentum transfer region, from which an exciton dispersion of 130 meV is observed. Semiempirical quantum chemical calculations reproduce well the momentum dependence of the measured dynamic dielectric responses, and thus unambiguously indicate that the lowest Frenkel exciton is confined within a fraction of the complex molecule. Our results demonstrate that IXS is a powerful tool for studying excitons in complex organic molecular systems. Besides the energy position, the IXS spectra provide a stringent test on the validity of the theoretically calculated exciton wave functions.Comment: 4 pages, 4 figure
    • …
    corecore