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A large amount of economic and financial news is now accessible through various news websites and social media platforms. Categorizing them into appropriate categories can be advantageous for various tasks, such as sentiment analysis and news-based market prediction. Unfortunately, news headlines categories may contain ambiguities due to the subjective nature of label assignment by authors or publishers. Consequently, achieving precise classification of news can be time-consuming and still reliant on human expertise. To tackle this challenging task, we proposed a hybrid approach to enhance the performance of economic and financial news classification. This approach combines baseline classifiers with a novel method called the Category Associated Feature Set (CAFS) classifier. CAFS transforms text input from the lexicon-space into the entity-space and discovers associations between entities and classes, akin to association rule learning. Experimental results on three datasets demonstrated that the proposed method is comparable to existing approaches and exhibits a significant improvement in the classification results for out-of-domain datasets. Additionally, employing CAFS in tandem with the existing text classification baselines can provide a general categorizer for distinguishing news categories across various sources without the need for extensive fine-tuning of the parameters associated with those classification baselines. This confirms that utilizing CAFS in a hybrid approach is appropriate and suitable for economic and financial news classification. [ABSTRACT FROM AUTHOR]

In this study, the effects of Cl and Br surface doping on the surfaces' structural stability of CH3NH3PbI3 (MAPbI3) perovskite have been investigated using the density functional theory. Its aim is to pursue how to stabilize a flat surfaces structure (no vacancy) of the MAPbI3 perovskite in overcoming its chemical instability. In this calculation, the (001) texture of the MAPbI3 perovskite surface was modeled as a prototype. The 216-atom and 264-atom supercells were employed to imitate the Lead Iodide (PbI2)- and Methylammonium Iodine (MAI)-terminated surfaces, respectively. It was found that doping of either Cl or Br atoms on perovskite surfaces enhances the energies required for releasing PbI2 and MAI molecules from the surfaces, causing vacancies on the surfaces. This is owed to the binding energies between the Cl and Br dopants and their surrounding atoms on the surfaces being stronger than those created by the Iodine atom. This implies that the formation of surface vacancies—which causes perovskite's degradation—can be prevented by Cl and Br surface doping. The obtained results elucidate the capability of Cl and Br dopants on surface stabilization, describing why one should incorporate Cl/Br into MAPbI3 to overcome instability issues and enhance the efficiency of the MAPbI3-based perovskite solar cell. [ABSTRACT FROM AUTHOR]

In this work, Monte Carlo simulation was employed to investigate the competitive effect of non-magnetic defects and the thickness on the ferromagnetic behavior of Ising spins in a reduced geometry, i.e. thin-films. The magnetic properties were investigated as functions of temperature, defect concentration, and films’ thickness, especially in the ferromagnetic phase transition region. The finite size scaling was performed via the fourth order cumulant of the magnetization to extract the critical temperatures. From the results, the extracted critical temperatures agree well with previous theoretical investigation, where applicable. With increasing concentration of the nonmagnetic defects, the Ising phase-transition-point slightly shifts towards lower temperature, while the increase of films thickness enhances the critical temperature value. Being confirmed by the main-effect-plot analysis, the increase in thickness has much greater influences on the critical temperature than that of the defect concentration, which could be described in term of the average ferromagnetic interaction spin. As the role of the defect is negligence in the range of considered defect concentration (up to ten percent), it therefore suggests that the preparation of ferromagnetic films can be done in normal operating condition where defects usually occur. It may be not economically worth to aim for the perfectly smooth films when the associated application operates at temperatures away from the critical point.

Density functional theory was used to inspect the structural properties and morphotropic phase boundaries (MPBs) of Ag1-xKxNbO3 (AKN) solid solutions. Structural properties of pristine AgNbO3 in Pbcm and Pmc21 phases were firstly investigated. The obtained crystal structures were found to be in good agreement with those from experiments. From the formation energy calculation of AKN solid solutions, the coexistences between Pbcm and Pmc21 phases and between Bmm2 and Pm phases were found to be in the composition ranges of x<"0.46" and x>"0.46," respectively. Therefore, the MPB separating the antiferroelectric and the ferroelectric phases can be specified at x ≈ "0.46." This theoretical study provides x ≈ "0.46" as a suggestive composition probably useful to acquire superior piezoelectricity for the utilization of AKN with reduced volatility of alkali elements at the A-site. [ABSTRACT FROM AUTHOR]