Atomic Diffusion in α-iron across the Curie Point: An Efficient and Transferable Ab Initio-Based Modeling Approach.

An accurate prediction of atomic diffusion in Fe alloys is challenging due to thermal magnetic excitations and magnetic transitions. We propose an efficient approach to address these properties via a Monte Carlo simulation, using ab initio-based effective interaction models. The temperature evolution of self- and Cu diffusion coefficients in α-iron are successfully predicted, particularly the diffusion acceleration around the Curie point, which requires a quantum treatment of spins.

Equilibrium Vacancy Concentration Driven by Undetectable Impurities.

By means of ab initio calculations combined to statistical mechanics, we provide new evidence that an experimentally undetectable tiny amount of impurities can be responsible for drastic changes in vacancy concentrations ([V]), inducing large deviations from an Arrhenius law even at low temperature. It is the case of O and N in α-Fe. The present finding is fully compatible with existing experiments, and changes the previous common vision that C has the dominant effect.

Perfectionism in gifted students: moderating effects of goal orientation and contingent self-worth.

We examined the moderating effects of mastery goals and academic contingency of self-worth (CSW-A) on how perfectionistic discrepancy associates with academic efficacy and satisfaction with life among gifted students in middle and high school. Participants in this study were 144 gifted students from 6th to 12th grade in a suburban Midwest U.S.

Profiles of acculturative adjustment patterns among Chinese international students.

This is the first study to empirically identify distinct acculturative adjustment patterns of new international students over their first 3 semesters in the United States. The sample consisted of 507 Chinese international students studying in the United States. Using psychological distress as an indicator of acculturative adjustment, measured over 4 time points (prearrival, first semester, second semester, and third semester), 4 distinct groups of student adjustment trajectories emerged: (a) a group exhibiting high levels of psychological distress across each time point (consistently distressed; 10%), (b) a group with decreasing psychological distress scores from Time 1 to Time 2 (relieved; 14%), (c), those with a sharp peak in psychological distress at Time 2 and Time 3 (culture-shocked; 11%), and (d) a group with relatively consistent low psychological distress scores (well-adjusted; 65%).

Structure and magnetism of bulk Fe and Cr: from plane waves to LCAO methods.

Magnetic, structural and energetic properties of bulk Fe and Cr were studied using first-principles calculations within density functional theory (DFT). We aimed to identify the dependence of these properties on key approximations of DFT, namely the exchange-correlation functional, the pseudopotential and the basis set. We found a smaller effect of pseudopotentials (PPs) on Fe than on Cr.

Stability and mobility of mono- and di-interstitials in alpha-Fe.

We report a detailed ab initio study of the stability and migration of self-interstitial atoms (SIAs) and di-interstitials (di-SIAs) in alpha-Fe. The <110> dumbbell is confirmed to be the most stable SIA configuration, 0.7 eV below the <111> dumbbell.