Korea University

About: Korea University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Thin film. The organization has 39756 authors who have published 82424 publications receiving 1860927 citations. The organization is also known as: Bosung College & Bosung Professional College.

Anomalous absorption of electromagnetic waves by 2D transition metal carbonitride Ti3CNTx (MXene)

Abstract: Lightweight, ultrathin, and flexible electromagnetic interference (EMI) shielding materials are needed to protect electronic circuits and portable telecommunication devices and to eliminate cross-talk between devices and device components. Here, we show that a two-dimensional (2D) transition metal carbonitride, Ti3CNTx MXene, with a moderate electrical conductivity, provides a higher shielding effectiveness compared with more conductive Ti3C2Tx or metal foils of the same thickness. This exceptional shielding performance of Ti3CNTx was achieved by thermal annealing and is attributed to an anomalously high absorption of electromagnetic waves in its layered, metamaterial-like structure. These results provide guidance for designing advanced EMI shielding materials but also highlight the need for exploring fundamental mechanisms behind interaction of electromagnetic waves with 2D materials.

Machine Learning Predictions of Molecular Properties: Accurate Many-Body Potentials and Nonlocality in Chemical Space

Abstract: Simultaneously accurate and efficient prediction of molecular properties throughout chemical compound space is a critical ingredient toward rational compound design in chemical and pharmaceutical industries. Aiming toward this goal, we develop and apply a systematic hierarchy of efficient empirical methods to estimate atomization and total energies of molecules. These methods range from a simple sum over atoms, to addition of bond energies, to pairwise interatomic force fields, reaching to the more sophisticated machine learning approaches that are capable of describing collective interactions between many atoms or bonds. In the case of equilibrium molecular geometries, even simple pairwise force fields demonstrate prediction accuracy comparable to benchmark energies calculated using density functional theory with hybrid exchange-correlation functionals; however, accounting for the collective many-body interactions proves to be essential for approaching the “holy grail” of chemical accuracy of 1 kcal/mol ...

Schooling Quality in a Cross Section of Countries

Abstract: We investigate the determinants of educational quality in a newly-constructed panel data set that includes output and input measures for a broad number of countries The results show that family inputs and school resources are closely related to school outcomes, as measured by internationally comparable test scores, repetition rates, and drop-out rates Family characteristics, such as income and education of parents, have strong effects on student performance The findings also indicate that more school resources- especially smaller class sizes but probably also higher teacher salaries and greater school length- enhance educational outcomes

A Meta-analysis of the Effectiveness of Intervention Programs Designed to Support Autonomy

Abstract: The twofold purpose of the present study was, first, to determine whether training intervention programs designed to help people support the autonomy of others are effective and, second, to identify the set of conditions that allowed these interventions to be most effective. A meta-analysis of the findings from 19 studies with 20 effect sizes showed that the training programs were, overall, effective with a weighted effect size of 0.63. Moderator analyses of the overall effect size showed that the relatively more effective intervention programs were structured in ways that trained multiple elements of autonomy support and were presented in relatively brief (1–3 h) sessions in a laboratory training setting that focused on skill-based activities and utilized multiple types of media to deliver its content. Furthermore, relatively effective intervention programs were offered to teachers (rather than to other professionals), trainees (rather than to experienced professionals), and individuals with an autonomy (rather than a control) causality orientation. Though the small number of included studies warrants caution, results generally affirmed the effectiveness of autonomy-supportive training programs and identified the conditions under which future programs can be designed to be highly effective.

Measurement of the branching ratio of B ¯ →d (∗)τ- ν ¯ τ relative to B ¯ →d (∗) - ν ¯ decays with hadronic tagging at Belle

Abstract: We report a measurement of the branching fraction ratios R(D)(()*()) of (B) over bar -> D-(*())tau(-)(nu) over bar (tau) relative to (B) over bar -> D-(*())l(-)(nu) over barl (where l = e or mu) using the full Belle data sample of 772 x 10(6)B (B) over bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The measured values are R(D) = 0.375 +/- 0.064(stat) +/- 0.026(syst) and R(D*) = 0.293 +/- 0.038 (stat) +/- 0.015 (syst). The analysis uses hadronic reconstruction of the tag-side B meson and purely leptonic t decays. The results are consistent with earlier measurements and do not show a significant deviation from the standard model prediction.