Fast-Rate Capable Electrode Material with Higher Energy Density than LiFePO4: 4.2V LiVPO4F Synthesized by Scalable Single-Step Solid-State Reaction

Use of compounds that contain fluorine (F) as electrode materials in lithium ion batteries has been considered, but synthesizing single-phase samples of these compounds is a difficult task. Here, it is demonstrated that a simple scalable single-step solid-state process with additional fluorine source can obtain highly pure LiVPO4F. The resulting material with submicron particles achieves very high rate capability approximate to 100 mAh g(-1) at 60 C-rate (1-min discharge) and even at 200 C-rate (18 s discharge). It retains superior capacity, approximate to 120 mAh g(-1) at 10 C charge/10 C discharge rate (6-min) for 500 cycles with >95% retention efficiency. Furthermore, LiVPO4F shows low polarization even at high rates leading to higher operating potential >3.45 V (approximate to 3.6 V at 60 C-rate), so it achieves high energy density. It is demonstrated for the first time that highly pure LiVPO4F can achieve high power capability comparable to LiFePO4 and much higher energy density (approximate to 521 Wh g(-1) at 20 C-rate) than LiFePO4 even without nanostructured particles. LiVPO4F can be a real substitute of LiFePO4.1114Ysciescopu

Temperature-dependent properties of the magnetic order in single-crystal BiFeO3

We report neutron diffraction and magnetization studies of the magnetic order in multiferroic BiFeO3. In ferroelectric monodomain single crystals, there are three magnetic cycloidal domains with propagation vectors equivalent by crystallographic symmetry. The cycloid period slowly grows with increasing temperature. The magnetic domain populations do not change with temperature except in the close vicinity of the N{\P}eel temperature, at which, in addition, a small jump in magneti- zation is observed. No evidence for the spin-reorientation transitions proposed in previous Raman and dielectric studies is found. The magnetic cycloid is slightly anharmonic for T=5 K. The an- harmonicity is much smaller than previously reported in NMR studies. At room temperature, a circular cycloid is observed, within errors. We argue that the observed anharmonicity provides important clues for understanding electromagnons in BiFeO3.Comment: In Press at PR

Best Practices and Performance-Based HR System in Korea

The purpose of this paper is to review major changes in the HR system in Korea and to suggest five propositions that need to be studied for better understanding of the configuration of performance-based HR system in Korea. The HR system in Korea went through great transformations after the financial crisis in the late 1990s. The performance-based HR system, which many Korean companies currently claim to have, is thought to have originated from the notion of so-called best practices of leading U.S. companies. In the framework of best practices, there is one universal HR practice set that can be applied to any situations. Although Korea maintained much of its unique organizational culture and HR practices, Korea also modified its HR system after the best practices to a great extent. By understanding the similarities and differences between the performance-based HR system and best practices, we will be able to better understand the current Korean HR system. In this study we call for empirical work on the changing configuration of HR system in Korea. We suggest five propositions that will be crucial in understanding the similarities and differences between the performance-based HR system and best practices

Structural Investigation of BaIrO3_3 by Neutron Diffraction

We report a temperature-dependent neutron diffraction (ND) study on polycrystalline monoclinic BaIrO$_3$ which is famous for charge density wave (CDW) and weak ferromagnetic phase transitions at T$_C$$\sim$180 K simultaneously. A Rietveld analysis on the ND patterns reveals that even though there is no symmetry breaking in crystal structure, a noticeable change in the four kinds of IrO$_{6}$ octahedra is isolated as the temperature approaches to T$_C$. Based on the structure analysis results, we calculated the $d$-orbital energy level splittings by crystal electric field for each type of the IrO$_6$ octahedra. By taking into account the strong spin-orbit coupling in Ir 5$d$ orbitals and the lattice distortions obtained from the ND analysis, we propose an electronic configuration model to understand the phase transition of the system, where an effective $J_{\rm eff, 1/2}$ Mott insulating phase and a charge gap phase induced by bonding states between the $J_{\rm eff,1/2}$ states compete each other.Comment: To appear in Journal of the Korean Physical Societ

ECG-QA: A Comprehensive Question Answering Dataset Combined With Electrocardiogram

Question answering (QA) in the field of healthcare has received much attention due to significant advancements in natural language processing. However, existing healthcare QA datasets primarily focus on medical images, clinical notes, or structured electronic health record tables. This leaves the vast potential of combining electrocardiogram (ECG) data with these systems largely untapped. To address this gap, we present ECG-QA, the first QA dataset specifically designed for ECG analysis. The dataset comprises a total of 70 question templates that cover a wide range of clinically relevant ECG topics, each validated by an ECG expert to ensure their clinical utility. As a result, our dataset includes diverse ECG interpretation questions, including those that require a comparative analysis of two different ECGs. In addition, we have conducted numerous experiments to provide valuable insights for future research directions. We believe that ECG-QA will serve as a valuable resource for the development of intelligent QA systems capable of assisting clinicians in ECG interpretations.Comment: 39 pages (9 pages for main text, 2 pages for references, 28 pages for supplementary materials

Singe ferroelectric and chiral magnetic domain of single-crystalline BiFeO3_3 in an electric field

We report polarized neutron scattering and piezoresponse force microscopy studies of millimeter-sized single crystals of multiferroic BiFeO$_3$. The crystals, grown below the Curie temperature, consist of a single ferroelectric domain. Two unique electric polarization directions, as well as the populations of equivalent spiral magnetic domains, can be switched reversibly by an electric field. A ferroelectric monodomain with a single-$q$ single-helicity spin spiral can be obtained. This level of control, so far unachievable in thin films, makes single-crystal BiFeO$_3$ a promising object for multiferroics research.Comment: 4 figures in separate jpg file

Doping Dependence of Spin-Lattice Coupling and Two-Dimensional Ordering in Multiferroic Hexagonal Y₁₋ₓLuₓMnO₃ (0 ≤ x ≤ 1)

We have examined a complete phase diagram of Y1-x Lu xMnO3 with 0≤x≤1 by using bulk measurements and neutron-diffraction studies. With increasing Lu concentration, Curie-Weiss temperature and Neel temperature are found to increase continuously while the two-dimensional nature of short-range magnetic correlation persists even in the paramagnetic phase throughout the entire doping range. At the same time, the lattice constants and the unit-cell volume get contracted with Lu doping, i.e., chemical pressure effect. This decrease in the lattice constants and the unit-cell volume then leads naturally to an increased magnetic exchange interaction as found in our local spin-density approximation band calculations. We also discover that there is strong correlation in the temperature dependence of a volume anomaly at TN and the magnetic moments

EHRSQL: A Practical Text-to-SQL Benchmark for Electronic Health Records

We present a new text-to-SQL dataset for electronic health records (EHRs). The utterances were collected from 222 hospital staff, including physicians, nurses, insurance review and health records teams, and more. To construct the QA dataset on structured EHR data, we conducted a poll at a university hospital and templatized the responses to create seed questions. Then, we manually linked them to two open-source EHR databases, MIMIC-III and eICU, and included them with various time expressions and held-out unanswerable questions in the dataset, which were all collected from the poll. Our dataset poses a unique set of challenges: the model needs to 1) generate SQL queries that reflect a wide range of needs in the hospital, including simple retrieval and complex operations such as calculating survival rate, 2) understand various time expressions to answer time-sensitive questions in healthcare, and 3) distinguish whether a given question is answerable or unanswerable based on the prediction confidence. We believe our dataset, EHRSQL, could serve as a practical benchmark to develop and assess QA models on structured EHR data and take one step further towards bridging the gap between text-to-SQL research and its real-life deployment in healthcare. EHRSQL is available at https://github.com/glee4810/EHRSQL.Comment: Published as a conference paper at NeurIPS 2022 (Track on Datasets and Benchmarks)