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Mathew L. Kelley

Publications and source records attributed to Mathew L. Kelley.

3 recordsLinked to original sources

ChemNLP: A Natural Language Processing based Library for Materials Chemistry Text Data

In this work, we present the ChemNLP library that can be used for 1) curating open access datasets for materials and chemistry literature, developing and comparing traditional machine learning, transformers and graph neural network models for 2) classifying and clustering texts, 3) named entity recognition for large-scale text-mining, 4) abstractive summarization for generating titles of articles from abstracts, 5) text generation for suggesting abstracts from titles, 6) integration with density functional theory dataset for identifying potential candidate materials such as superconductors, and 7) web-interface development for text and reference query. We primarily use the publicly available arXiv and Pubchem datasets but the tools can be used for other datasets as well. Moreover, as new models are developed, they can be easily integrated in the library. ChemNLP is available at the websites: https://github.com/usnistgov/chemnlp and https://jarvis.nist.gov/jarvischemnlp.

cond-mat.mtrl-sci

Spectroscopic assessment of short-term nitric acid doping of epitaxial graphene

This work reports information on the transience of hole doping in epitaxial graphene devices when nitric acid is used as an adsorbent. Under vacuum conditions, desorption processes are monitored by electrical and spectroscopic means to extract the relevant timescales from the corresponding data. It is of vital importance to understand the reversible nature of hole doping because such device processing can be a suitable alternative to large-scale, metallic gating. Most measurements are performed post-exposure at room temperature, and, for some electrical transport measurements, at 1.5 K. Vacuum conditions are applied to many measurements to replicate the laboratory conditions under which devices using this doping method would be measured. The relevant timescales from transport measurements are compared with results from X-ray photoelecton spectroscopy and Fourier transform infrared spectroscopy measurements, with the latter performed at ambient conditions and accompanied by calculations of the spectra in the Reststrahlen band.

cond-mat.mes-hall

A Comprehensive Study on the Spectroscopic Characterization and Molecular Dynamics Simulation of Pristine and Functionalized Graphene Nanoplatelets for Gas Sensing Applications

Graphene nanoplatelets (GnPs) are promising candidates for gas sensing applications because they have a high surface area to volume ratio, high conductivity, and a high temperature stability. Also, they cost less to synthesize, and they are lightweight, making them even more attractive than other 2D carbon-based materials. In this paper, the surface and structural properties of pristine and functionalized GnPs, specifically with carboxyl, ammonia, carboxyl, nitrogen, oxygen, fluorocarbon, and argon, were examined with Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction (XRD) to determine the functional groups present and effects of those groups on the structural and vibrational properties. We attribute certain features in the observed Raman spectra to the variations in concentration of the functionalized GnPs. XRD results show smaller crystallite sizes for functionalized GnPs samples that agree with images acquired with scanning electron microscopy. Lastly, a molecular dynamics simulation is employed to gain a better understanding of the Raman and adsorption properties of pristine GnPs.

physics.chem-ph