jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: I. I. Agafonova | O. S. Bayandina | Y. Gong | C. Henkel | Kee‐Tae Kim | M. G. Kozlov | Boy Lankhaar | S. A. Levshakov | K. M. Menten | W. Ubachs | И. Е. Вальтц | Wei Yang
Source: arXiv (Cornell University) (preprint, 2024-07-16)
Field: Chemistry — Spectroscopy

Hyperfine structure of the methanol molecule as traced by Class I methanol masers We present results on simultaneous observations of Class~I methanol masers at 25, 36, and 44 GHz towards 22 Galactic targets carried out with the Effelsberg 100-m telescope. The study investigates relations between the hyperfine (HF) structure of the torsion-rotation transitions in CH3OH and maser activity. By analyzing the radial velocity shifts between different maser lines together with the patterns of the HF structure based on laboratory measurements and quantum-chemical calculations, we find that in any source only one specific HF transition forms the maser emission and that this transition changes from source to source. The physical conditions leading to this selective behavior are still unclear. Using accurate laboratory rest frequencies for the 25 GHz transitions, we have refined the centre frequencies for the HF multiplets at 36, 44, and 95 GHz: f_36 = (36169.2488 +/- 0.0002_stat +/- 0.0004_sys) MHz. f_44 = (44069.4176 +/- 0.0002_stat +/- 0.0004_sys) MHz, and f_95 = (95169.4414 +/- 0.0003_stat +/- 0.0004_sys) MHz. Comparison with previous observations of 44 GHz masers performed 6-10 years ago with a Korean 21-m KVN telescope towards the same targets confirms the kinematic stability of Class~I maser line profiles during this time interval and reveals a systematic radial velocity shift of 0.013 +/- 0.005 km/s between the two telescopes. Maser ; Methanol ; Hyperfine structure ; Molecule ; Class (philosophy) ; Astrophysics ; Physics ; Chemistry ; Astronomy ; Photochemistry ; Atomic physics ; Organic chemistry ; Quantum mechanics ; Computer science Molecular Spectroscopy and Structure ; Astrophysics and Star Formation Studies ; Advanced Chemical Physics Studies
Authors: Francisco Silva-Santos | Rúben D. M. Silva | Y. Guerra | Maykol Oliveira | Zhuohang Yu | Mauricio Terrones | Antônio Francisco de Souza Filho | Rafael S. Alencar | Bartolomeu C. Viana
Source: arXiv (Cornell University) (preprint, 2024-02-05)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Phonon and exciton temperature-dependent properties of twisted MoS$_2$ In the present work, Raman and photoluminescence spectroscopies were used to study the dynamics of phonons and different excitons of MoS$_2$ bilayer under a rotation of 29$^{\circ}$ dependent of the temperature. The twisted bilayer (T-2L) of MoS$_2$ was obtained through mechanical exfoliation, and subsequently rotated using a dimethyl polysiloxane (PDMS) substrate and deterministic transferred to a SiO$_2$ substrate. The Raman spectrum of the twisted bilayer presents three peaks E$'$ (386 cm$^{-1}$), A$'_{1}$ (405 cm$^{-1}$) and an FA$'$ peak at approximately 409 cm$^{-1}$ linked to the A$'_{1}$ mode, which is attributed to a Moiré pattern phonon. Both modes (A$'_{1}$ and FA$'$) are dependent of light polarization in a way that demonstrates an effective coupling between the layers. It was also verified through the Grüneisen parameter, an increase in the anharmonicity of the mode in the E$'$ plane and a decrease the same for A$'_{1}$. In the PL measurements, the appearance of an exciton in T-2L was verified, which generated a second shoulder measured at $\approx$1.58 eV attributed to an indirect transition of an I trion. The interaction between the rotated monolayers of MoS$_{2}$ proved to be an important parameter for possible fine-tuning of the properties of bilayer samples. Phonon ; Exciton ; Condensed matter physics ; Physics ; Materials science Organic and Molecular Conductors Research ; 2D Materials and Applications
Authors: Francesca Scalerandi | Wiebke Albrecht | Alexander Skorikov | Nathalie Claes | Sara Bals
Source: BIO Web of Conferences (article, 2024-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Reliable tomographic reconstructions of (sub)-nm gaps in plasmonic gold dimers for correlation to optical properties Plasmon ; Materials science ; Tomographic reconstruction ; Optics ; Tomography ; Physics ; Optoelectronics Gold and Silver Nanoparticles Synthesis and Applications ; Plasmonic and Surface Plasmon Research ; Advanced Fluorescence Microscopy Techniques
Authors: Ashok Gurung | Mohammad Fatin Ishtiyaq | S. P. Alpay | John Mangeri | Serge Nakhmanson
Source: arXiv (Cornell University) (preprint, 2024-07-29)
Field: Materials Science — Materials Chemistry

Extrinsic Dielectric Response due to Domain Wall Motion in Ferroelectric BaTiO$_3$ BaTiO$_3$ (BTO) is a prototypical perovskite ferroelectric, whose dielectric permittivity and loss spectra -- which are strongly temperature and frequency dependent -- include contributions from inhomogeneous polarization patterns, with polar domain walls (DWs) being the most common types. In order to elucidate how DWs influence dielectric response, we utilized a continuum approach based on the Landau-Ginzburg theory to model field-dependent properties of polydomain tetragonal phase of BTO near room temperature and above. A system with 180$^\circ$ DWs was evaluated as a case study, with both position-resolved and volume-averaged dielectric susceptibility and loss computed at different temperatures for a range of applied field frequencies and amplitudes. Our results demonstrate that cooperative dipole fluctuations in the vicinity of the DW provide a large (extrinsic) contribution to the system dielectric response relative to the intrinsic contribution stemming from within the domain. Dynamics of the DW profile fluctuations under applied field can be represented by a combination of breathing and sliding vibrational motions, with each exhibiting distinct dependence on the field frequency and amplitude. The implications of this behavior are important for understanding and improving control of coupled functional properties in ferroelectric materials, including their dielectric, electromechanical, and electrooptical responses. Furthermore, this investigation provides a computational benchmark for future studies and can be readily extended to other topological polarization patterns in ferroelectrics. Ferroelectricity ; Dielectric ; Dielectric response ; Materials science ; Domain wall (magnetism) ; Domain (mathematical analysis) ; Motion (physics) ; Condensed matter physics ; Physics ; Optoelectronics ; Mathematics ; Classical mechanics ; Mathematical analysis ; Quantum mechanics Ferroelectric and Piezoelectric Materials ; Ultrasonics and Acoustic Wave Propagation
Authors: Assem Alassaf | János Koltai | Amador García‐Fuente | László Oroszlány
Source: arXiv (Cornell University) (preprint, 2024-08-21)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Surface reconstruction limited magnetism of the nodal loop semimetal Ca$_3$P$_2$ Nodal loop semimetals are topological materials with drumhead surface states characterized by reduced kinetic energy. If the Fermi energy of such a system is near these nondispersive states interaction among charge carriers substantially impacts their electronic structure. The emergence of magnetism in these surface states is one of the possible consequences. Ca3P2 an already synthesized material possesses a remarkably large nodal loop which is situated exactly at the Fermi level of the bulk system. In the present work, we investigate how surface magnetism is impacted by surface reconstruction and lattice termination in finite slabs in this material. We show that a slight deviation from the stoichiometric occupation of Ca sites results in the stabilization of magnetic patterns. NODAL ; Magnetism ; Loop (graph theory) ; Semimetal ; Surface (topology) ; Physics ; Materials science ; Condensed matter physics ; Mathematics ; Combinatorics ; Geometry ; Biology ; Band gap Magnetic Properties of Alloys ; Magnetic properties of thin films ; Rare-earth and actinide compounds
Authors: Dieter Weber | David Landers | Chen Huang | Emanuela Liberti | Emiliya Poghosyan | M. T. Bryan | Alexander Clausen | Daniel G. Stroppa | Angus I. Kirkland | E. Müller | Andrew Stewart | Rafal E. Dunin–Borkowski
Source: arXiv (Cornell University) (preprint, 2024-03-13)
Field: Materials Science — Surfaces, Coatings and Films

Calibrating coordinate system alignment in a scanning transmission electron microscope using a digital twin Calibrating coordinate system alignment in a scanning transmission electron microscope using a digital twin. Supplementary material This deposition contains supplementary material for a paper on coordinate system calibration in 4D STEM. A preprint of the paper is available at https://arxiv.org/abs/2403.08538. Contents 20221025_154811.zip: Overfocused 4D STEM test dataset overfocus.sif: Apptainer image with complete software stack. apptainer run --writable overfocus.sif to execute. It starts a Jupyterlab instance with two notebooks, one to genreate test data and the other to perform the interactive adjustment. This documents the software version that was used for the figures in the paper. requirements.txt: Python package versions of dependencies in overfocus.sif. COM - Jupyter Notebook - Google Chrome 2023-01-25 12-40-07_processed.mp4: Screen capture video with explanation of the first live calibration with an early prototype. video description.docx: Explanation of the plots and adjustment process in the screen capture video. Microscope-Calibration.tar.gz: Repository archive of the software and examples for calibration in the version used in the paper. TemGym.tar.gz: Repository archive of TemGym Basic in the version used in the paper. Scanning transmission electron microscopy ; Transmission (telecommunications) ; Optics ; Conventional transmission electron microscope ; Microscope ; Computer science ; Transmission electron microscopy ; Materials science ; Physics ; Telecommunications Electron and X-Ray Spectroscopy Techniques ; Advanced Electron Microscopy Techniques and Applications ; Optical measurement and interference techniques
Authors: Haidong Tian | Emilio Codecido | Dan Mao | Kevin Zhang | Shi Che | Kenji Watanabe | Takashi Taniguchi | Dmitry Smirnov | Eun-Ah Kim | Marc Bockrath | Chun Ning Lau
Source: arXiv (Cornell University) (preprint, 2024-02-22)
Field: Materials Science — Materials Chemistry

Dominant 1/3-filling Correlated Insulator States and Orbital Geometric Frustration in Twisted Bilayer Graphene Geometric frustration is a phenomenon in a lattice system where not all interactions can be satisfied, the simplest example being antiferromagnetically coupled spins on a triangular lattice. Frustrated systems are characterized by their many nearly degenerate ground states, leading to non-trivial phases such as spin ice and spin liquids. To date most studies are on geometric frustration of spins; much less explored is orbital geometric frustration. For electrons in twisted bilayer graphene (tBLG) at denominator 3 fractional filling, Coulomb interactions and the Wannier orbital shapes are predicted to strongly constrain spatial charge ordering, leading to geometrically frustrated ground states that produce a new class of correlated insulators (CIs). Here we report the observation of dominant denominator 3 fractional filling insulating states in large angle tBLG; these states persist in magnetic fields and display magnetic ordering signatures and tripled unit cell reconstruction. These results are in agreement with a strong-coupling theory of symmetry-breaking of geometrically frustrated fractional states. Frustration ; Bilayer graphene ; Graphene ; Condensed matter physics ; Insulator (electricity) ; Bilayer ; Materials science ; Physics ; Nanotechnology ; Chemistry ; Optoelectronics ; Membrane Graphene research and applications ; Fullerene Chemistry and Applications ; Fiber-reinforced polymer composites
Authors: Papa Faye | Djicknack Dione | Oumar Ndiaye | Moussa Sy | Nogaye Ndiaye | Alassane Traoré | Ababacar Sadikhe Ndao
Source: American Journal of Modern Physics (article, 2024-09-29)
Field: Chemistry — Analytical Chemistry

Using Nuclear Methods in X-ray Fluorescence Spectroscopy to Quantify Heavy Metals in Senegalese Powdered Milk: Improving Milk Safety Applying X-ray fluorescence (XRF), this study investigated the elemental analysis and heavy metal contents in five Senegalese powdered milk samples (V1, L1, H1, G1, and D1). The primary focus was on Aluminum (Al), Calcium (Ca), Potassium (K), Phosphorous (P), and Chlorine (Cl), with special attention given to the compliance of these elements with safety standards. The analysis revealed that Aluminum was either absent or present in minimal quantities across all samples, suggesting that the powdered milk is largely free from this element. Calcium levels were found to be consistently higher than the Acceptable Maximum Level (AML) across all samples, with the H1 sample significantly exceeding the AML by approximately 11.1 times, with a concentration of 27,745.06 ± 310.16 ppm. This indicates a potential risk of excessive calcium intake from this sample. Potassium concentrations varied significantly; while the V1 sample remained within acceptable limits, the G1 sample exhibited potassium levels substantially above the AML, reaching 51,058.15 ± 456.13 ppm, which could pose health concerns if consumed in large quantities. Chlorine concentrations generally met the AML, except for the G1 sample, which slightly surpassed the limit at 3631.04 ± 31.23 ppm. The phosphorus content in the H1 sample was notably high, though further details are needed to fully assess its implications. The study underscores the necessity for continuous monitoring of heavy metal and elemental levels in powdered milk to ensure consumer safety. Heavy metals ; Materials science ; Fluorescence spectroscopy ; Fluorescence ; Spectroscopy ; X-ray fluorescence ; Radiochemistry ; Environmental chemistry ; Chemistry ; Physics ; Optics Heavy Metals in Plants ; Trace Elements in Health ; Nutritional Studies and Diet
Authors: Phan Xuan Le | Pham Hong Cong
Source: Indonesian Journal of Electrical Engineering and Computer Science (article, 2024-08-30)
Field: Materials Science — Materials Chemistry

Effects of TiO2 in graphene-quantum-dot film on lighting color uniformity of a white light-emitting diodes Improvement in color uniformity of white light-emitting diodes (WLED) is one of the imperative goals for high-quality solid-state illumination. The conventional WLED model with a single yellow phosphor YAG:Ce&lt;sup&gt;3+&lt;/sup&gt; (TiO&lt;sub&gt;2&lt;/sub&gt;@GD) is proposed to fulfill this goal. The TiO&lt;sub&gt;2&lt;/sub&gt;@GD composites prove to possess excellent biocompatibility, low toxicity, and thermal and chemical stability, holding great potential in high-power WLED production. By maintaining a constant GDs content of 10 wt%, the research explores the impact of varying TiO&lt;sub&gt;2&lt;/sub&gt; doping concentrations on the lighting performance of the WLEDs via the mean of light scattering. The TiO&lt;sub&gt;2&lt;/sub&gt;@GD layer also induces a red-shift in the emitted light spectrum, contributing to a reduction in color variation. While a decline in luminosity and color rendering performance becomes evident with excessive TiO&lt;sub&gt;2&lt;/sub&gt; content, the study underscores the potential of TiO&lt;sub&gt;2&lt;/sub&gt;@GD as a viable diffusing layer for LEDs to obtain improved angular uniformity of color distribution. Quantum dot ; Optoelectronics ; White light ; Diode ; Materials science ; Light-emitting diode ; Graphene ; White (mutation) ; Optics ; Nanotechnology ; Physics ; Chemistry Quantum Dots Synthesis And Properties ; Carbon and Quantum Dots Applications ; GaN-based semiconductor devices and materials
Authors: Kyana Mohammadi | Duraichelvan Raju | Mahdi Derayatifar | Simona Bǎdilescu | Muthukumaran Packirisamy
Source: Proceedings of the International Conference of Theoretical and Applied Nanoscience and Nanotechnology (article, 2024-06-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Tuning of Morphology and Plasmonic Properties of Gold Nanoislands through Thermal Budgeting Plasmon ; Materials science ; Thermal ; Morphology (biology) ; Optoelectronics ; Thermal management of electronic devices and systems ; Nanotechnology ; Physics ; Mechanical engineering ; Meteorology ; Engineering Gold and Silver Nanoparticles Synthesis and Applications
Authors: Võ Tiến Phong | F. Guinea | Cyprian Lewandowski
Source: arXiv (Cornell University) (preprint, 2024-07-19)
Field: Chemistry — Spectroscopy

Optical Absorption and Emission from Wannier-Stark Spectra of Moiré Superlattices Using a formalism based on the non-Abelian Berry connection, we explore quantum geometric signatures of Wannier-Stark spectra in two-dimensional superlattices. The Stark energy can be written as \textit{intraband} Berry phases, while Zener tunneling is given by \textit{interband} Berry connections. We suggest that the gaps induced by interband hybridization can be probed by THz optical absorption and emission spectroscopy. This is especially relevant to modern moiré materials wherein mini-bands are often spectrally entangled, leading to strong interband hybridization in the Wannier-Stark regime. Furthermore, owing to their large superlattice constants, both the low-field and high-field regimes can be accessed in these materials using presently available technology. Importantly, even at moderate electric fields, we find that stimulated emission can dominate absorption, raising the possibility of lasing at practically relevant parameter regimes. Superlattice ; Moiré pattern ; Spectral line ; Absorption (acoustics) ; Absorption spectroscopy ; Stark effect ; Materials science ; Atomic physics ; Optics ; Physics ; Molecular physics ; Optoelectronics ; Quantum mechanics Spectroscopy and Laser Applications
Authors: Marco Dirindin
Source: arXiv (Cornell University) (preprint, 2024-10-10)
Field: Materials Science — Ceramics and Composites

Glassy dynamics and crystalline local order in two-dimensional amorphous silica We reassess the modeling of amorphous silica bilayers as a two-dimensional classical system whose particles interact with an effective pairwise potential. We show that it is possible to reparameterize the potential developed by Roy, Heyde, and Heuer to quantitatively match the structural details of the experimental samples. We then study the glassy dynamics of the reparameterized model at low temperatures. Using appropriate cage-relative correlation functions, which suppress the effect of Mermin-Wagner fluctuations, we highlight the presence of two well-defined Arrhenius regimes separated by a narrow crossover region, which we connect to the thermodynamic anomalies and the changes in the local structure. We find that the bond-orientational order grows steadily below the crossover temperature and is associated to transient crystalline domains of nanometric size. These findings raise fundamental questions about the nature of glass structure in two dimensions and provide guidelines to interpret the experimental data. Amorphous solid ; Order (exchange) ; Dynamics (music) ; Amorphous silica ; Materials science ; Chemical physics ; Statistical physics ; Crystallography ; Chemical engineering ; Chemistry ; Physics ; Business ; Engineering Glass properties and applications
Authors: Zhongyang Xing | Jiahui Liao | Zhongjie Xu | Xiang’ai Cheng | Jiangbin Zhang
Source: Photonics (article, 2024-10-28)
Field: Materials Science — Electronic, Optical and Magnetic Materials

The Design of Highly Reflective All-Dielectric Metasurfaces Based on Diamond Resonators All-dielectric metasurfaces offer a low-loss alternative to plasmonic metasurfaces. We proposed the configuration for high-reflectivity all-dielectric metasurfaces based on single-crystal diamond (SCD) resonators on fused silica substrate and conducted simulations to optimize and analyze such a configuration via the FDTD solver. We utilized GMR as the design principle to select the configuration and the substrate material, and analyzed the scattering properties of a single SCD resonator by multipole decomposition. Then, we demonstrated that both the cylindrical resonators in square lattice and frustum-shaped resonators in hexagonal lattice can achieve near-unity reflectivity (&gt;99.99%) and ultra-low absorption (&lt;0.001%) at 795 nm, the typical alkali-metal laser wavelength. Additionally, we demonstrated that such a design is quite tolerant of fabrication errors and further supports its potential for realistic applications. To expand the functionality of such devices across multiple wavelengths, dual-band high-reflectivity metasurfaces at 744 nm and 828 nm were also designed. Our work is quite useful for designing diamond-based highly reflective mirrors, paving the way for low-loss all-dielectric reflective metasurfaces in high-power laser applications. Diamond ; Resonator ; Dielectric ; Materials science ; Optoelectronics ; Optics ; Physics Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Antenna Design and Analysis
Authors: Chirag Nepal | Wanqiu Chen | Zhong Chen | John A. Wrobel | Ling Xie | Wenjing Liao | Chunlin Xiao | Adrew Farmer | Malcolm Moos | Wendell Jones | Xian Chen | Charles Wang
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2024-09-13)
Field: Chemistry — Spectroscopy

Epigenomic, transcriptomic and proteomic characterizations of reference samples A variety of newly developed next-generation sequencing technologies are making their way rapidly into the research and clinical applications, for which accuracy and cross-lab reproducibility are critical, and reference standards are much needed. Our previous multicenter studies under the SEQC-2 umbrella using a breast cancer cell line with paired B-cell line have produced a large amount of different genomic data including whole genome sequencing (Illumina, PacBio, Nanopore), HiC, and scRNA-seq with detailed analyses on somatic mutations, single-nucleotide variations (SNVs), and structural variations (SVs). However, there is still a lack of well-characterized reference materials which include epigenomic and proteomic data. Here we further performed ATAC-seq, Methyl-seq, RNA-seq, and proteomic analyses and provided a comprehensive catalog of the epigenomic landscape, which overlapped with the transcriptomes and proteomes for the two cell lines. We identified >7,700 peptide isoforms, where the majority (95%) of the genes had a single peptide isoform. Protein expression of the transcripts overlapping CGIs were much higher than the protein expression of the non-CGI transcripts in both cell lines. We further demonstrated the evidence that certain SNVs were incorporated into mutated peptides. We observed that open chromatin regions had low methylation which were largely regulated by CG density, where CG-rich regions had more accessible chromatin, low methylation, and higher gene and protein expression. The CG-poor regions had higher repressive epigenetic regulations (higher DNA methylation) and less open chromatin, resulting in a cell line specific methylation and gene expression patterns. Our studies provide well-defined reference materials consisting of two cell lines with genomic, epigenomic, transcriptomic, scRNA-seq and proteomic characterizations which can serve as standards for validating and benchmarking not only on various omics assays, but also on bioinformatics methods. It will be a valuable resource for both research and clinical communities. Epigenomics ; Computational biology ; Transcriptome ; Computer science ; Chemistry ; Biology ; Genetics ; DNA methylation ; Gene ; Gene expression Advanced Proteomics Techniques and Applications ; Molecular Biology Techniques and Applications ; Single-cell and spatial transcriptomics