1,582 research outputs found

    How are Asian Americans Seen and Evaluated? Examining Ethnic Stereotypes and their Cultural Complexity

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    Human stereotypes are more complicated and subtle than scholars or lay people often think. Based on the EPA (i.e., evaluation, potency and accuracy) theory of stereotypes (Lee, 2011; Lee, B., W. & Luo, 2007; Lee, J., & McCauley, 2013; Lee, McCauley & Jussim, 2013; Lee, V. S., & Ma, 2007), it was hypothesized and found that stereotypes of Asian Americans are derived on the basis of both evaluative considerations (prejudice) and a realistic assessment of group characteristics. This produces a pattern of stereotypic judgments that contains both agreement and disagreement when comparing stereotypes of Asian Americans among different perceiver groups (European Americans, non-Asian Minority-Americans). The results of the present study also highlight complexities that arise when one considers the effect of inter-group contact on stereotyping. Specifically, an increase in the frequency of inter-group contact was associated with a reduction in negative stereotyping, whereas an increase in the quality or closeness of inter-group contact was associated with an increase in negative stereotyping. It is concluded that inter-group stereotyping reflects a complex mixture of psychological processes that are in need of further investigation

    Kinetics of Oxygen Surface Exchange on Epitaxial Ruddlesden–Popper Phases and Correlations to First-Principles Descriptors

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    Through alignment of theoretical modeling with experimental measurements of oxygen surface exchange kinetics on (001)-oriented La[subscript 2–x]Sr[subscript x]MO[subscript 4+δ] (M = Co, Ni, Cu) thin films, we demonstrate here the capability of the theoretical bulk O 2p-band centers to correlate with oxygen surface-exchange kinetics of the Ruddlesden–Popper oxide (RP[subscript 214]) (001)-oriented thin films. In addition, we demonstrate that the bulk O 2p-band centers can also correlate with the experimental activation energies for bulk oxygen transport and oxygen surface exchange of both the RP[subscript 214] and the perovskite polycrystalline materials reported in the literature, indicating the effectiveness of the bulk O 2p-band centers in describing the associated energetics and kinetics. We propose that the opposite slopes of the bulk O 2p-band center correlations between the RP[subscript 214] and the perovskite materials are due to the intrinsic mechanistic differences of their oxygen surface exchange kinetics and bulk anionic transport.United States. Department of Energy. Solid State Energy Conversion Allianc (Core Technology Program Funding Opportunity Number DEFE0009435)Skoltech-MIT Center for Electrochemical EnergyOak Ridge National Laboratory. Scientific User Facilities DivisionUnited States. Department of Energy. Office of Basic Energy Science. Division of Materials Sciences and EngineeringNational Energy Research Scientific Computing Center (U.S.) (grant number CNMS2013-292

    Joint Experimental and Computational O-17 and H-1 Solid State NMR Study of Ba2In2O4(OH)(2) Structure and Dynamics

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    This is the final version of the article. It first appeared from ACS Publications via http://dx.doi.org/10.1021/acs.chemmater.5b00328A structural characterization of the hydrated form of the brownmillerite-type phase Ba2In2O5, Ba2In2O4(OH)2, is reported using experimental multinuclear NMR spectroscopy and density functional theory (DFT) energy and GIPAW NMR calculations. When the oxygen ions from H2O fill the inherent O vacancies of the brownmillerite structure, one of the water protons remains in the same layer (O3) while the second proton is located in the neighboring layer (O2) in sites with partial occupancies, as previously demonstrated by Jayaraman et al. ( Solid State Ionics 2004, 170, 25?32) using X-ray and neutron studies. Calculations of possible proton arrangements within the partially occupied layer of Ba2In2O4(OH)2 yield a set of low energy structures; GIPAW NMR calculations on these configurations yield 1H and 17O chemical shifts and peak intensity ratios, which are then used to help assign the experimental MAS NMR spectra. Three distinct 1H resonances in a 2:1:1 ratio are obtained experimentally, the most intense resonance being assigned to the proton in the O3 layer. The two weaker signals are due to O2 layer protons, one set hydrogen bonding to the O3 layer and the other hydrogen bonding alternately toward the O3 and O1 layers. 1H magnetization exchange experiments reveal that all three resonances originate from protons in the same crystallographic phase, the protons exchanging with each other above approximately 150 ?C. Three distinct types of oxygen atoms are evident from the DFT GIPAW calculations bare oxygens (O), oxygens directly bonded to a proton (H-donor O), and oxygen ions that are hydrogen bonded to a proton (H-acceptor O). The 17O calculated shifts and quadrupolar parameters are used to assign the experimental spectra, the assignments being confirmed by 1H?17O double resonance experiments.This work was supported in part by Grants DMR050612 and CHE0714183 from the National Science Foundation and Grant DESC0001284 from the Department of Energy (supporting Y.- L.L. and D.M.), by an Advanced Fellowship from the EU-ERC (C.P.G.), and by the EPSRC (D.S.M.). F.B. thanks the EU Marie Curie actions FP7 for an International Incoming fellowship (Grant No. 275212) and Clare Hall, University of Cambridge, for a Research Fellowship

    Joint Experimental and Computational 17O and 1H Solid State NMR Study of Ba2In2O4(OH)2 Structure and Dynamics.

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    A structural characterization of the hydrated form of the brownmillerite-type phase Ba2In2O5, Ba2In2O4(OH)2, is reported using experimental multinuclear NMR spectroscopy and density functional theory (DFT) energy and GIPAW NMR calculations. When the oxygen ions from H2O fill the inherent O vacancies of the brownmillerite structure, one of the water protons remains in the same layer (O3) while the second proton is located in the neighboring layer (O2) in sites with partial occupancies, as previously demonstrated by Jayaraman et al. (Solid State Ionics2004, 170, 25-32) using X-ray and neutron studies. Calculations of possible proton arrangements within the partially occupied layer of Ba2In2O4(OH)2 yield a set of low energy structures; GIPAW NMR calculations on these configurations yield 1H and 17O chemical shifts and peak intensity ratios, which are then used to help assign the experimental MAS NMR spectra. Three distinct 1H resonances in a 2:1:1 ratio are obtained experimentally, the most intense resonance being assigned to the proton in the O3 layer. The two weaker signals are due to O2 layer protons, one set hydrogen bonding to the O3 layer and the other hydrogen bonding alternately toward the O3 and O1 layers. 1H magnetization exchange experiments reveal that all three resonances originate from protons in the same crystallographic phase, the protons exchanging with each other above approximately 150 °C. Three distinct types of oxygen atoms are evident from the DFT GIPAW calculations bare oxygens (O), oxygens directly bonded to a proton (H-donor O), and oxygen ions that are hydrogen bonded to a proton (H-acceptor O). The 17O calculated shifts and quadrupolar parameters are used to assign the experimental spectra, the assignments being confirmed by 1H-17O double resonance experiments.This work was supported in part by Grants DMR050612 and CHE0714183 from the National Science Foundation and Grant DESC0001284 from the Department of Energy (supporting Y.- L.L. and D.M.), by an Advanced Fellowship from the EU-ERC (C.P.G.), and by the EPSRC (D.S.M.). F.B. thanks the EU Marie Curie actions FP7 for an International Incoming fellowship (Grant No. 275212) and Clare Hall, University of Cambridge, for a Research Fellowship.This is the final version of the article. It first appeared from ACS Publications via http://dx.doi.org/10.1021/acs.chemmater.5b0032
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