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1. Tabular Transfer Learning via Prompting LLMs

Author

Nam, Jaehyun, Song, Woomin, Park, Seong Hyeon, Tack, Jihoon, Yun, Sukmin, Kim, Jaehyung, Oh, Kyu Hwan, and Shin, Jinwoo

Subjects
Computer Science - Computation and Language, Computer Science - Artificial Intelligence, Computer Science - Machine Learning
Abstract

Learning with a limited number of labeled data is a central problem in real-world applications of machine learning, as it is often expensive to obtain annotations. To deal with the scarcity of labeled data, transfer learning is a conventional approach; it suggests to learn a transferable knowledge by training a neural network from multiple other sources. In this paper, we investigate transfer learning of tabular tasks, which has been less studied and successful in the literature, compared to other domains, e.g., vision and language. This is because tables are inherently heterogeneous, i.e., they contain different columns and feature spaces, making transfer learning difficult. On the other hand, recent advances in natural language processing suggest that the label scarcity issue can be mitigated by utilizing in-context learning capability of large language models (LLMs). Inspired by this and the fact that LLMs can also process tables within a unified language space, we ask whether LLMs can be effective for tabular transfer learning, in particular, under the scenarios where the source and target datasets are of different format. As a positive answer, we propose a novel tabular transfer learning framework, coined Prompt to Transfer (P2T), that utilizes unlabeled (or heterogeneous) source data with LLMs. Specifically, P2T identifies a column feature in a source dataset that is strongly correlated with a target task feature to create examples relevant to the target task, thus creating pseudo-demonstrations for prompts. Experimental results demonstrate that P2T outperforms previous methods on various tabular learning benchmarks, showing good promise for the important, yet underexplored tabular transfer learning problem. Code is available at https://github.com/jaehyun513/P2T., Comment: COLM 2024

Published
2024

6. In Situ Engineering of the Electrode–Electrolyte Interface for Stabilized Overlithiated Cathodes

Author

Evans, Tyler, Piper, Daniela Molina, Sun, Huaxing, Porcelli, Timothy, Kim, Seul Cham, Han, Sang Sub, Choi, Yong Seok, Tian, Chixia, Nordlund, Dennis, Doeff, Marca M, Ban, Chunmei, Cho, Sung‐Jin, Oh, Kyu Hwan, and Lee, Se‐Hee

Subjects
Engineering, Materials Engineering, Chemical Sciences, Physical Chemistry, Affordable and Clean Energy, Li-ion, cathode, interfaces, ionic liquids, lithium-manganese-rich, Physical Sciences, Nanoscience & Nanotechnology, Chemical sciences, Physical sciences
Abstract

The first-ever demonstration of stabilized Si/lithium-manganese-rich full cells, capable of retaining >90% energy over early cycling and >90% capacity over more than 750 cycles at the 1C rate (100% depth-of-discharge), is made through the utilization of a modified ionic-liquid electrolyte capable of forming a favorable cathode-electrolyte interface.

Published
2017

14. Improved Cycle Properties of All-Solid-State Li-Ion Batteries with Al2O3 Coating on the Silicon-Based Anode.

Author

Jeong, Jejun, Lee, Kikang, Carpenter, Cole, Shrestha, Sushovan, Kim, Jongbeom, Chung, Hee-Suk, Moon, Jeongtak, Oh, Kyu Hwan, Sun, Jeong-Yun, and Lee, Se-Hee

Subjects
IONIC conductivity, SILICON nanowires, LITHIUM-ion batteries, ALUMINUM oxide, ELECTRIC vehicles, ELECTRIC vehicle batteries, ANODES, PLASMA sheaths, AERODYNAMIC heating
Abstract

The demand for the development of high-capacity, safe, and long-life secondary batteries and the interest in all-solid-state batteries are increasing. The cycle performance of solid-state batteries is limited by interfacial phenomena at the electrolyte–anode interface hindering the ion diffusions. A multifunctional aluminum oxide (specifically, Al2O3) coating was created for application on silicon-based anodes in all-solid-state lithium-ion batteries. In an all-solid-state lithium-ion battery, the electrochemical properties of Al2O3 coating were enhanced. The coating was applied to provide stable artificial solid electrolyte interphase (SEI) layers on the silicon-based anodes. Al2O3 layers not only promote the diffusion of Li+ through the Li–Al–O, but their intrinsically low electronic conductivity also limits the transmission of electrons at the contact between the anode and the electrolyte. A Si alloy–polyacrylonitrile anode was prepared using Al2O3 coating as an artificial SEI layer by radio-frequency (RF) plasma. Radio-frequency sputtering was used to create a simple and economical Al2O3 coating. The cycle properties of silicon-based anodes were enhanced by the addition of the thin amorphous aluminum oxide layer (i.e., Al2O3 coating). After 100 charge–discharge cycles, the half-cell with the Al2O3 layer delivered a discharge capacity of 502.08 mAh g−1 and a capacity retention ratio of 58.86%. After 100 cycles, the sample without the Al2O3 layer had a discharge capacity of 278.48 mAh g−1 and capacity retention of 34.34%. Cells with an Al2O3 -coated anode retained high capacity after 100 cycles. Thus, the Al2O3 -coated Si-based anodes were cycled successfully in all-solid-state half-cells to produce functional high-performance lithium-ion batteries. In this study, we employed the vacuum deposition method, radio-frequency sputtering, to deposit very thin layer of aluminum oxide on the surface of fully fabricated anodes for improved cycling properties of all solid-state battery. This layer of aluminum oxide was confirmed using advanced elemental analysis techniques. The aluminum oxide layer with 1-min coating had much-improved cycling characteristics compared with those of the sample with no coatings. Previous studies have used theoretical calculations to report that an aluminum oxide coating layer improves the stability characteristics for sulfide-based solid electrolytes. In this paper, the actual stability improvement of the sulfide-based solid electrolyte was demonstrated in terms of much improved cycling characteristics throughout the cycling test. The appropriate amount of aluminum oxide coating decreases the decomposition of solid electrolyte and also decreases the consumption of Li ions during lithiation and delithiation. This surface modification technique can be utilized to improve the cycling stability of solid-state batteries, which is one of the critical factors for the early adoption of solid-state batteries for electric vehicle applications. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Role of bosonic modes in the mechanism of high temperature Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ superconductors using ultrafast optical techniques

Author

Zhu, Jian-Xin, Chia, Elbert E. M., Tamegai, T., Eisaki, H., Oh, Kyu-Hwan, Lee, S. -I., and Taylor, A. J.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

Using ultrafast optical techniques, we probe the hole-doping dependence of the electron-boson coupling constant $\lambda$ in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$. In the overdoped region, we observe a correlation between ($\lambda$) and the superconducting transition temperature $T_{c}$. Upon performing the McMillan analysis, however, we find that $\lambda$ is too small to explain the high $T_{c}$'s, and that the Coulomb pseudopotential $\mu^{\ast}$ is negative. Our analysis therefore reveals two components in the mechanism of high-$T_{c}$ superconductivity -- a dominant pre-existing pairing interaction, together with a weaker electron-phonon interaction that fine-tunes $T_{c}$., Comment: 4 pages, 4 eps figures

Published
2008

16. Observation of Competing Order in a High-$T_{c}$ Superconductor with Femtosecond Optical Pulses

Author

Chia, Elbert E. M., Zhu, Jian-Xin, Talbayev, D., Averitt, R. D., Oh, Kyu-Hwan, Jo, In-Sun, Lee, S. -I., and Taylor, A. J.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

We present studies of the photoexcited quasiparticle dynamics in Tl$_{2}$Ba$_{2}$Ca$_{2}$Cu$_{3}$O$_{y}$ (Tl-2223) using femtosecond optical techniques. Deep into the superconducting state (below 40 K), a dramatic change occurs in the temporal dynamics associated with photoexcited quasiparticles rejoining the condensate. This is suggestive of entry into a coexistence phase which, as our analysis reveals, opens a gap in the density of states (in addition to the superconducting gap), and furthermore, competes with superconductivity resulting in a depression of the superconducting gap., Comment: 5 pages, 3 figures

Published
2007
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48. Peel-and-Stick Integration of Atomically Thin Nonlayered PtS Semiconductors for Multidimensionally Stretchable Electronic Devices

Author

Han, Sang Sub, Ko, Tae-Jun, Shawkat, Mashiyat Sumaiya, Shum, Alex Ka, Bae, Tae-Sung, Chung, Hee-Suk, Ma, Jinwoo, Sattar, Shahid, Bin Hafiz, Shihab, Al Mahfuz, Mohammad M., Mofid, Sohrab Alex, Larsson, J. Andreas, Oh, Kyu Hwan, Ko, Dong-Kyun, Jung, Yeonwoong, Han, Sang Sub, Ko, Tae-Jun, Shawkat, Mashiyat Sumaiya, Shum, Alex Ka, Bae, Tae-Sung, Chung, Hee-Suk, Ma, Jinwoo, Sattar, Shahid, Bin Hafiz, Shihab, Al Mahfuz, Mohammad M., Mofid, Sohrab Alex, Larsson, J. Andreas, Oh, Kyu Hwan, Ko, Dong-Kyun, and Jung, Yeonwoong

Abstract

van der Waals (vdW) crystals with unparalleled electromechanical properties have been explored for transformative devices. Currently, the availability of 2D vdW crystals is rather limited in nature as they are only obtained from certain mother crystals with intrinsically possessed layered crystallinity and anisotropic molecular bonding. Recent efforts to transform conventionally non-vdW three-dimensional (3D) crystals into ultrathin 2D-like structures have seen rapid developments to explore device building blocks of unique form factors. Herein, we explore a "peel-and-stick" approach, where a nonlayered 3D platinum sulfide (PtS) crystal, traditionally known as a cooperate mineral material, is transformed into a freestanding 2D-like membrane for electromechanical applications. The ultrathin (???10 nm) 3D PtS films grown on large-area (>cm2) silicon dioxide/silicon (SiO2/Si) wafers are precisely "peeled" inside water retaining desired geometries via a capillary-force-driven surface wettability control. Subsequently, they are "sticked" on strain-engineered patterned substrates presenting prominent semiconducting properties, i.e., p-type transport with an optical band gap of ∼1.24 eV. A variety of mechanically deformable strain-invariant electronic devices have been demonstrated by this peel-and-stick method, including biaxially stretchable photodetectors and respiratory sensing face masks. This study offers new opportunities of 2D-like nonlayered semiconducting crystals for emerging mechanically reconfigurable and stretchable device technologies.

Published
2022
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