5,136 research outputs found

    CIE Software Check of luox.app

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    The University of Oxford has developed an open-access software platform known as luox, which incorporates elements of CIE publications for the calculation of certain quantities integrated from spectral data. Under the terms of a licence agreement between the University of Oxford and the CIE, the CIE has agreed to endorse the software following a black-box validation of the software. This is the report of that validation exercise, based on the work of an ad hoc task group of the CIE Board of Administration. The task group selected 43 spectrafrom various sources, 19 being spectra with 5 nm intervals and 24 being spectra with 1 nm intervals, and calculated luminance (illuminance), a-opic radiances (a-opic irradiances), a-opic equivalent daylight luminances (a-opic equivalent daylight illuminances), a-opic efficacies of luminous radiation, and chromaticity coordinates using both luox and a variety of other available reference calculation tools, both public and private. Tolerance intervals were established for each quantity, and the deviation between the test values from luox and thereference values were calculated for each spectrum. The results for all of these evaluations showed consistency between the test values and the reference values. Based on these results, the CIE approves the following statement concerning the luox software, as per the aforementioned licence agreement:“This software incorporates methods, formulae, spectral function calculations and spectra from the International Commission on Illumination (CIE). The CIE endorses this software having made a black-box evaluation of the software as of Feb. 11, 2021, finding that the software performs satisfactorily. This software is not a replacement for the CIE publications and works from which it is derived. The user is advised to consult the original publications and works for proper understanding of and calculation of the result of this software.

    Monte Carlo Simulation of Sinusoidally Modulated Superlattice Growth

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    The fabrication of ZnSe/ZnTe superlattices grown by the process of rotating the substrate in the presence of an inhomogeneous flux distribution instead of successively closing and opening of source shutters is studied via Monte Carlo simulations. It is found that the concentration of each compound is sinusoidally modulated along the growth direction, caused by the uneven arrival of Se and Te atoms at a given point of the sample, and by the variation of the Te/Se ratio at that point due to the rotation of the substrate. In this way we obtain a ZnSe1−x_{1-x}Tex_x alloy in which the composition xx varies sinusoidally along the growth direction. The period of the modulation is directly controlled by the rate of the substrate rotation. The amplitude of the compositional modulation is monotonous for small angular velocities of the substrate rotation, but is itself modulated for large angular velocities. The average amplitude of the modulation pattern decreases as the angular velocity of substrate rotation increases and the measurement position approaches the center of rotation. The simulation results are in good agreement with previously published experimental measurements on superlattices fabricated in this manner

    Atomic scale evolution of the surface chemistry in Li[Ni,Mn,Co]O2 cathode for Li-ion batteries stored in air

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    Layered LiMO2 (M = Ni, Co, Mn, and Al mixture) cathode materials used for Li-ion batteries are reputed to be highly reactive through their surface, where the chemistry changes rapidly when exposed to ambient air. However, conventional electron/spectroscopy-based techniques or thermogravimetric analysis fails to capture the underlying atom-scale chemistry of vulnerable Li species. To study the evolution of the surface composition at the atomic scale, here we use atom probe tomography and probed the surface species formed during exposure of a LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode material to air. The compositional analysis evidences the formation of Li2CO3. Site specific examination from a cracked region of an NMC811 particle also suggests the predominant presence of Li2CO3. These insights will help to design improved protocols for cathode synthesis and cell assembly, as well as critical knowledge for cathode degradatio

    Escape from adamantane: Scaffold optimization of novel P2X7 antagonists featuring complex polycycles

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    The adamantane scaffold, despite being widely used in medicinal chemistry, is not devoid of problems. In the recent years we have developed new polycyclic scaffolds as surrogates of the adamantane group with encouraging results in multiple targets. As an adamantane scaffold is a common structural feature in several P2X7 receptor antagonists, herein we report the synthesis and pharmacological evaluation of multiple replacement options of adamantane that maintain a good activity profile. Molecular modeling studies support the binding of the compounds to a site close to the central pore, rather than to the ATP-binding site and shed light on the structural requirements for novel P2X7 antagonists

    Beneficial immunostimulatory effect of short-term Chlorella supplementation: enhancement of natural Killer cell activity and early inflammatory response (Randomized, double-blinded, placebo-controlled trial)

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    Background - In vitro and animal studies have demonstrated that Chlorella is a potent biological response modifier on immunity. However, there were no direct evidences for the effect of Chlorella supplementation on immune/inflammation response in healthy humans. Methods - This study was designed for an 8-week randomized, double-blinded, placebo-controlled trial: 5g of Chlorella (n=23) or Placebo (n=28) as form of tablets. Mainly, cytotoxic activities of Natural killer (NK) cells and serum concentrations of interferon-¿, interleukin-1ß and interleukin-12 were measured. Results - After the 8-week, serum concentrations of interferon-¿ (

    Thermodynamic theory of epitaxial ferroelectric thin films with dense domain structures

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    A Landau-Ginsburg-Devonshire-type nonlinear phenomenological theory is presented, which enables the thermodynamic description of dense laminar polydomain states in epitaxial ferroelectric thin films. The theory explicitly takes into account the mechanical substrate effect on the polarizations and lattice strains in dissimilar elastic domains (twins). Numerical calculations are performed for PbTiO3 and BaTiO3 films grown on (001)-oriented cubic substrates. The "misfit strain-temperature" phase diagrams are developed for these films, showing stability ranges of various possible polydomain and single-domain states. Three types of polarization instabilities are revealed for polydomain epitaxial ferroelectric films, which may lead to the formation of new polydomain states forbidden in bulk crystals. The total dielectric and piezoelectric small-signal responses of polydomain films are calculated, resulting from both the volume and domain-wall contributions. For BaTiO3 films, strong dielectric anomalies are predicted at room temperature near special values of the misfit strain.Comment: 19 pages, 8 figure

    Partisan Asymmetries in Online Political Activity

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    We examine partisan differences in the behavior, communication patterns and social interactions of more than 18,000 politically-active Twitter users to produce evidence that points to changing levels of partisan engagement with the American online political landscape. Analysis of a network defined by the communication activity of these users in proximity to the 2010 midterm congressional elections reveals a highly segregated, well clustered partisan community structure. Using cluster membership as a high-fidelity (87% accuracy) proxy for political affiliation, we characterize a wide range of differences in the behavior, communication and social connectivity of left- and right-leaning Twitter users. We find that in contrast to the online political dynamics of the 2008 campaign, right-leaning Twitter users exhibit greater levels of political activity, a more tightly interconnected social structure, and a communication network topology that facilitates the rapid and broad dissemination of political information.Comment: 17 pages, 10 figures, 6 table

    Investigation of dosimetry in four human head models for planar monopole antenna with a coupling feed for LTE/WWAN/WLAN internal mobile phone

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    The objective of the present study is to evaluate the Specific Absorption Rate (SAR) within the human head model exposed to the radiation of planar monopole antenna with T-shaped coupling feed and an inductive shorting strip. The presented design has a compact structure, a planar configuration and occupying a small size of 36×20mm2. Two wide bands can be generated by the proposed antenna 546 MHz (734-1280 MHz) and 1066 MHz (1934-3000 MHz) for the LTE/WWAN/WLAN internal mobile phone. The antenna performance parameters comprising return loss, radiation patterns, and gain are discussed. In this research work four different human head models have been implemented: homogenous spherical head, spherical seven layer model, Specific Anthropomorphic Mannequin (SAM) phantom and HUGO human head model. On the other hand the effects of operating frequency and gap distance between the mobile phone antenna and the human head model on distributions of the SAR inside the human head are investigated. All the simulations are done for three different distances between the antenna and the head model (5 mm, 10 mm and 20 mm). Moreover, the SAR levels for the head tissues are calculated in accordance to the two currently accepted standards: Federal Communications Commission (FCC) and International Commission on Non-Ionizing Radiation Protection (ICNIRP)

    Theories for influencer identification in complex networks

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    In social and biological systems, the structural heterogeneity of interaction networks gives rise to the emergence of a small set of influential nodes, or influencers, in a series of dynamical processes. Although much smaller than the entire network, these influencers were observed to be able to shape the collective dynamics of large populations in different contexts. As such, the successful identification of influencers should have profound implications in various real-world spreading dynamics such as viral marketing, epidemic outbreaks and cascading failure. In this chapter, we first summarize the centrality-based approach in finding single influencers in complex networks, and then discuss the more complicated problem of locating multiple influencers from a collective point of view. Progress rooted in collective influence theory, belief-propagation and computer science will be presented. Finally, we present some applications of influencer identification in diverse real-world systems, including online social platforms, scientific publication, brain networks and socioeconomic systems.Comment: 24 pages, 6 figure
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