jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Weijie Chen | Huiying Xu | Fu‐Xiaomin Liu | Kaifeng Chen | Zhi Zhou | Wei Yi
Source: Angewandte Chemie (article, 2024-03-19)
Field: Chemistry — Organic Chemistry

Chiral Osmium(II)/Salox Species Enabled Enantioselective γ‐C(sp<sup>3</sup>)−H Amidation: Integrated Experimental and Computational Validation For the Ligand Design and Reaction Development Abstract Herein, multiple types of chiral Os(II) complexes have been designed to address the appealing yet challenging asymmetric C(sp 3 )−H functionalization, among which the Os(II)/Salox species is found to be the most efficient for precise stereocontrol in realizing the asymmetric C(sp 3 )−H amidation. As exemplified by the enantioenriched pyrrolidinone synthesis, such tailored Os(II)/Salox catalyst efficiently enables an intramolecular site‐/enantioselective C(sp 3 )−H amidation in the γ‐position of dioxazolone substrates, in which benzyl, propargyl and allyl groups bearing various substituted forms are well compatible, affording the corresponding chiral γ‐lactam products with good er values (up to 99 : 1) and diverse functionality (&gt;35 examples). The unique performance advantage of the developed chiral Os(II)/Salox system in terms of the catalytic energy profile and the chiral induction has been further clarified by integrated experimental and computational studies. Enantioselective synthesis ; Osmium ; Chemistry ; Intramolecular force ; Catalysis ; Propargyl ; Combinatorial chemistry ; Ligand (biochemistry) ; Stereochemistry ; Diastereomer ; Chirality (physics) ; Organic chemistry ; Ruthenium ; Receptor ; Physics Catalytic C–H Functionalization Methods ; Synthesis and Catalytic Reactions ; Asymmetric Hydrogenation and Catalysis
Authors: Raphaël Hahn | D. Comparat
Source: The European Physical Journal D (article, 2024-06-01)
Field: Chemistry — Spectroscopy

High repetition rate sub-ns electron pulses from pulsed-resonance Rydberg field-ionization (PRRFI) Atomic physics ; Ionization ; Rydberg formula ; Electron ; Rydberg atom ; Electric field ; Laser ; Resonance (particle physics) ; Electron ionization ; Pulse (music) ; Spectroscopy ; Physics ; Optics ; Ion Mass Spectrometry Techniques and Applications ; Advanced Electron Microscopy Techniques and Applications ; Ion-surface interactions and analysis
Authors: Chun‐Hao Huang | Chandra Shekar Gantepogu | Peng‐Jen Chen | Ting‐Hsuan Wu | Wei-Rein Liu | Kung‐Hsuan Lin | Chi‐Liang Chen | Ting-Kuo Lee | Ming-Jye Wang | Maw‐Kuen Wu
Source: Nanomaterials (article, 2024-08-16)
Field: Materials Science — Materials Chemistry

Substrate Charge Transfer Induced Ferromagnetism in MnSe/SrTiO3 Ultrathin Films The observation of superconductivity in MnSe at 12 GPa motivated us to investigate whether superconductivity could be induced in MnSe at ambient conditions. A strain-induced structural change in the ultrathin film could be one route to the emergence of superconductivity. In this report, we present the physical property of MnSe ultrathin films, which become tetragonal (stretched <i>ab</i>-plane and shortened <i>c</i>-axis) on a (001) SrTiO<sub>3</sub> (STO) substrate, prepared by the pulsed laser deposition (PLD) method. The physical properties of the tetragonal MnSe ultrathin films exhibit very different characteristics from those of the thick films and polycrystalline samples. The tetragonal MnSe films show substantial conductivity enhancement, which could be associated with the presence of superparamagnetism. The optical absorption data indicate that the electron transition through the indirect bandgap to the conduction band is significantly enhanced in tetragonal MnSe. Furthermore, the X-ray Mn <i>L</i>-edge absorption results also reveal an increase in unoccupied state valance bands. This theoretical study suggests that charge transfer from the substrate plays an important role in conductivity enhancement and the emergence of a ferromagnetic order that leads to superparamagnetism. Tetragonal crystal system ; Materials science ; Condensed matter physics ; Substrate (aquarium) ; Ferromagnetism ; Superconductivity ; Pulsed laser deposition ; Crystallite ; Band gap ; Superparamagnetism ; Magnetization ; Thin film ; Crystal structure ; Nanotechnology ; Optoelectronics ; Crystallography ; Chemistry ; Metallurgy ; Physics ; Magnetic field Electronic and Structural Properties of Oxides ; ZnO doping and properties ; Iron-based superconductors research
Authors: José Ramón Serrano | Pedro Piqueras | Enrique José Sanchís | Carla Conde
Source: Preprints.org (preprint, 2024-05-01)
Field: Materials Science — Materials Chemistry

Analysis of Altitude and Ambient Temperature Effects on the Reactivity of Oxidation Catalysts in the Presence of H2 Worldwide emission standards are now required to cover engine operation under extreme ambient conditions, which affect the raw emissions and the efficiency of the exhaust aftertreatment systems. These regulations also target new combustion technologies for decarbonization, such as neat hydrogen (H2) combustion or dual-fuel strategies, which involve a challenge to the analysis of exhaust aftertreatment systems requirements and performance. This work addresses the impact of high altitude and low ambient temperature conditions on the reactivity of an oxidation catalyst in the presence of H2. A reaction mechanism is proposed to cover the main conversion paths of CO, HC, and H2, including the formation and consumption of high-energy surface reaction intermediates. The mechanism has been implemented into a faster-than-real-time reduced-order model for multi-layer washcoat honeycomb catalytic converters. The model was utilized to investigate the effect of H2 concentration on the reactivity of CO and HC within the catalyst under various operating and ambient conditions. By applying the model and examining the selectivity towards different reaction pathways in the presence H2, insights into surface intermediates and reactivity across different cross-sections of the monolith were obtained. This analysis discusses the underlying causes of reactivity changes promoted by H2 and its relative importance as a function of driving boundary conditions. Reactivity (psychology) ; Catalysis ; Altitude (triangle) ; Chemistry ; Environmental science ; Organic chemistry ; Medicine ; Mathematics Catalytic Processes in Materials Science
Authors: Amina Houimi | Mohamed A. Basyooni | Mücahit Yılmaz | Yasin Ramazan Eker
Source: Physical Chemistry Chemical Physics (article, 2024-01-01)
Field: Materials Science — Polymers and Plastics

MoO<sub>3</sub>nanowire growth on VO<sub>2</sub>/WO<sub>3</sub>for thermochromic applications This study explores the structural, electronic, and optical properties of sandwich-structured thin films composed of WO<sub>3</sub>, MoWO<sub>3</sub>, and MoO<sub>3</sub> as window layers on VO<sub>2</sub>/WO<sub>3</sub><i>via</i> a physical vapor deposition method. Morphological analysis demonstrates the evolution of distinct nanowires, offering insights into the lattice strain of the VO<sub>2</sub> layer toward high-performance thermochromatic devices. Temperature-dependent sheet resistivity is investigated, showcasing significant improvements in conductivity for samples with MoO<sub>3</sub> as a window layer. The electrical and optical properties of the MoO<sub>3</sub>/VO<sub>2</sub>/WO<sub>3</sub> device showed a phase transition temperature (<i>T</i><sub>c</sub>) of 36.8 °C, a transmittance luminous (<i>T</i><sub>lum</sub>) of 54.57%, and a solar modulation ability (Δ<i>T</i><sub>sol</sub>) of 12.43. This comprehensive analysis contributes to understanding the growth of nanowires on multi-layered thin films, offering valuable insights into potential applications in bright windows. Thermochromism ; Nanowire ; Materials science ; Nanotechnology ; Chemical engineering ; Condensed matter physics ; Physics ; Engineering Transition Metal Oxide Nanomaterials ; Gas Sensing Nanomaterials and Sensors ; Ga2O3 and related materials
Authors: Štěpán Krobot | Přemysl Menčík | Kateřina Chaloupková | Ján Bočkaj | Sára Vach Agócsová | Michala Rampichová | Věra Hedvičáková | Pavol Alexy | Radek Přikryl | Veronika Melčová
Source: International Journal of Bioprinting (article, 2024-12-18)
Field: Materials Science — Biomaterials

Optimizing printability and mechanical properties of poly(3-hydroxybutyrate) (P3HB) biocomposite blends and their biological response to Saos-2 cells Bone tissue engineering requires scaffolds with three-dimensional structures that facilitate vascularization and new tissue growth. 3D printing, especially through fused deposition modeling (FDM), has emerged as an effective method for creating complex structures with high reproducibility. Early research in this area demonstrated the potential of poly(&amp;epsilon;-caprolactone) (PCL) and poly(L-lactide) (PLLA) scaffolds for bone regeneration. Recently, polylactide (PLA) and polyhydroxyalkanoates (PHAs) have garnered attention for their biocompatibility and ability to support cell proliferation. Among PHAs, poly(3-hydroxybutyrate) (P3HB) shows promise due to its intrinsic biocompatibility and resorbability, making it a candidate for FDM-based scaffold fabrication. In the presented study, we aim to develop and optimize a biocompatible P3HB-based composite material for bone tissue engineering, incorporating PLA, hydroxyapatite (HA), and the plasticizer Syncroflex3114 (SN) to enhance mechanical properties and printability. This composite was processed into filaments for 3D printing and characterized through thermal, mechanical, and biological evaluations. Using a design of experiment (DoE) approach, we investigated factors such as temperature performance, warping, degradation, and strength to determine the optimal composition for use in tissue engineering. Four optimal mixture compositions fulfilling the optimization criteria of having the most suitable properties for bone tissue engineering, namely the best printability and maximum mechanical properties,&amp;nbsp; were obtained. The mixtures were optimized specifically for minimum warping coefficient (0.5); maximum flexural strength (66.9 MPa); maximum compression modulus (2.4 GPa); and maximum compression modulus (2.3 GPa) with a warping coefficient of no more than one at the same time. In conclusion, the study shows a new possible way to effectively develop and test 3D printed P3HB-based scaffolds with specifically optimized material properties. Biocomposite ; Materials science ; Composite material ; Poly-3-hydroxybutyrate ; Polymer science ; Chemical engineering ; Engineering ; Composite number biodegradable polymer synthesis and properties ; Microplastics and Plastic Pollution ; Additive Manufacturing and 3D Printing Technologies
Authors: Zhihao Gong | Yechen Xun | Zhuang Qian | Kai Chang | Jingshan Qi | Hua Wang
Source: arXiv (Cornell University) (preprint, 2024-01-07)
Field: Materials Science — Materials Chemistry

One-dimensional Multiferroic Semiconductor WOI3: Unconventional Anisotropic d^1 Rule and Bulk Photovoltaic Effect The pursuit of multiferroic magnetoelectrics, combining simultaneous ferroelectric and magnetic orders, remains a central focus in condensed matter physics. Here we report the centrosymmetric, one-dimensional (1D) antiferromagnetic WOI$_3$ undergoes a strain-induced ferroelectric distortion. The paraelectric-ferroelectric transition is originated from the unconventional anisotropic $d^1$ mechanism, where an unpaired d electron of each W$^{5+}$ ion contributes to magnetic orders. Employing a Heisenberg model with Dzyaloshinskii-Moriya interaction, we predict an antiferromagnetic spin configuration as the paraelectric ground state, transitioning to a ferroelectric phase with noncollinear spin arrangement under uniaxial strain. The ferroelectric polarization and noncollinear spin arrangement can be manipulated by varying the applied strain. While the energy barriers for switching ferroelectric polarizations with magnetic orders are on the order of a few dozen of meV, the shift current bulk photovoltaic effect (BPVE) exhibits remarkable differences, providing a precise and valuable tool for experimentally probing the interplay of ferroelectric and magnetic orders in 1D WOI$_3$. Ferroelectricity ; Condensed matter physics ; Antiferromagnetism ; Materials science ; Multiferroics ; Dielectric ; Anisotropy ; Physics ; Optics ; Optoelectronics 2D Materials and Applications ; Acoustic Wave Resonator Technologies ; Multiferroics and related materials
Authors: Alireza Khalilian | Bowen Yu | Yasha Yi
Source: arXiv (Cornell University) (preprint, 2024-03-29)
Field: Materials Science — Surfaces, Coatings and Films

Polarization-based Metalenses with High Numerical Aperture and Focusing Efficiency Utilizing Silicon-rich Nitride We explore the cutting-edge application of silicon-rich nitride (SRN) in the realm of high numerical aperture (NA) metalens design, focusing on the crucial role of pitch size optimization in amplifying lens efficiency through advanced simulations. Our investigation unveils how the exceptional tunable high refractive index of SRN can be harnessed to achieve significant advancements in metalens performance. By meticulously designing and simulating two innovative SRN-based metalenses - Mk1, with an NA of 0.9, reaching an impressive 75% focusing efficiency with full width at half maximum (FWHM) of 0.53λ, and Mk2, with an NA of 0.99, achieving a 42% efficiency while maintaining an FWHM of 0.48λ. We demonstrate the critical influence of reduced pitch size on enhancing efficiency. This study not only highlights the unparalleled potential of SRN in optimizing metalens efficiency but also represents a significant leap forward in the field of nanophotonics, offering new pathways for the development of highly efficient flat photonic devices. Polarization (electrochemistry) ; Silicon nitride ; Materials science ; Nitride ; Optics ; Silicon ; Optoelectronics ; Numerical aperture ; Physics ; Nanotechnology ; Wavelength ; Chemistry Optical Coatings and Gratings ; GaN-based semiconductor devices and materials
Authors: Nazar Saidov | K. Miliyanchuk | Maria LESKIV | L. Havela | R. Gladyshevskii
Source: Chemistry of Metals and Alloys (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Crystal structures of the R2Ni2Ga (R = Tb, Dy) hydrides and tuning of the hydrogenation properties by p-element substitution Intermetallics with the structure type W2CoB2 (Pearson symbol oI10, space group Immm) are promising materials for hydrogen storage.The present work reports on hydrogenation of the W2CoB2-type intermetallics Tb2Ni2Ga and Dy2Ni2Ga1-xAlx (x = 0, 0.2, 0.5, 0.8, 1).The hydrides were synthesized at room temperature and hydrogen pressures below ambient (p(H2) = 0.4-0.5 bar).Hydrogenation led to substantial lattice expansion, reaching V/V = 18.4% for Tb2Ni2Ga, and increasing from 18.5% to 22.5% with increasing Al content within the Dy2Ni2Ga1-xAlx series.The change in the lattice is highly anisotropic: the increase of the lattice parameters b and c is accompanied by a decrease of the lattice parameter a.Based on an analysis of the free space in the metal matrix of Tb2Ni2GaH5.1, a model for the crystal structure is proposed with two hydrogen sites inside tetrahedra [Tb3Ni] and [Tb2Ni2], yielding a theoretical composition of Tb2Ni2GaH6 for the hydride.Limited substitution of Ga for Al improved the hydrogenation properties of the R2Ni2Ga compounds, leading to faster hydrogenation kinetics and higher hydrogen content.Intermetallic / Hydride / X- Crystal structure ; Substitution (logic) ; X-ray crystallography ; Crystal (programming language) ; Single crystal Hydrogen Storage and Materials ; Rare-earth and actinide compounds ; Magnetic Properties of Alloys
Authors: Aksel Kobiałka | Oladunjoye A. Awoga | Martin Leijnse | T. Domański | Patric Holmvall | Annica M. Black‐Schaffer
Source: arXiv (Cornell University) (preprint, 2024-05-20)
Field: Materials Science — Materials Chemistry

Topological superconductivity in Fibonacci quasicrystals We investigate the properties of a Fibonacci quasicrystal (QC) arrangement of a one-dimensional topological superconductor, such as a magnetic atom chain deposited on a superconducting surface. We uncover a general mutually exclusive competition between the QC properties and the topological superconducting phase with Majorana bound states (MBS): there are no MBS inside the QC gaps and the MBS never behaves as QC subgap states, and likewise, no critical, or winding, QC subgap states exist inside the topological superconducting gaps. Surprisingly, despite this competition, we find that the QC is still highly beneficial for realizing topological superconductivity with MBS. It both leads to additional large nontrivial regions with MBS in parameter space, that are topologically trivial in crystalline systems, and increases the topological gap protecting the MBS. We also find that shorter approximants of the Fibonacci QC display the largest benefits. As a consequence, our results promote QCs, and especially their short approximants, as an appealing platform for improved experimental possibilities to realize MBS as well as generally highlights the fundamental interplay between different topologies. Quasicrystal ; Fibonacci number ; Superconductivity ; Physics ; Topology (electrical circuits) ; Condensed matter physics ; Theoretical physics ; Mathematics ; Combinatorics Quasicrystal Structures and Properties ; Advanced Mathematical Theories and Applications ; Nanocluster Synthesis and Applications
Authors: Sergei Tretiak
Source: OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (article, 2024-02-02)
Field: Chemistry — Physical and Theoretical Chemistry

Electronic and optical response of Ru(II) complexes functionalized by methyl, carboxylate groups: joint theoretical and experimental study New photovoltaic and photocatalysis applications have been recently proposed based on the hybrid Ru(II)-bipyridine-complex/semiconductor quantum dot systems. In order to attach the complex to the surface of a semiconductor, a linking bridge - a carboxyl group - is added to one or two of the 2,2{prime}-bipyridine ligands. Such changes in the ligand structure, indeed, affect electronic and optical properties and consequently, the charge transfer reactivity of Ru-systems. In this study, we apply both theoretical and experimental approaches to analyze the effects brought by functionalization of bipyridine ligands with the methyl, carboxyl, and carboxilate groups on the electronic structure and optical response of the Ru(II) bipyridine complex. First principle calculations based on density functional theory (DFT) and linear response time dependent density functional theory (TDDFT) are used to simulate the ground and excited-state structures of functionalized Ru-complexes in the gas phase, as well as in acetonitrile solution. In addition, an inelaborate Frenkel exciton model is used to explain the optical activity and splitting patterns of the low-energy excited states. All theoretical results nicely complement experimental absorption spectra of Ru-complexes and contribute to their interpretation. We found that the carboxyl group breaks the degeneracy of two low-energy optically bright excited states and red-shifts the absorption spectrum, while leaves ionization and affinity energies of complexes almost unchanged. Experimental studies show a high probability of deprotonation of the carbboxyl group in the Ru-complexes resulted in a slight blue shift and decrease of intensities of the low energy absorption peaks. Comparison of experimental and theoretical linear response spectra of deprotanated complexes demonstrate strong agreement when acetonitrile solvent is used in simulations. A polar solvent is found to play an important role in calculations of optical spectra: it stabilizes the energy of states localized on the carboxyl or carboxylate groups eliminating artificial charge transport states, which typically appear in TDDFT calculations. Thus, it is validated that the excited-state structure of the functionalized Ru-complexes, specifically in the case of the deprotonated functions, can be accurately modeled by TDDFT with the addition of a dielectric continuum in simulations. Chemistry ; Carboxylate ; Joint (building) ; Electronic structure ; Photochemistry ; Computational chemistry ; Stereochemistry ; Polymer chemistry Photochemistry and Electron Transfer Studies ; Inorganic and Organometallic Chemistry ; Metal complexes synthesis and properties
Authors: Andreas Herklotz | R.S. Roth | Zhi Xiang Chong | Liang Luo | Joong Mok Park | Matthew Brahlek | Jigang Wang | Kathrin Dörr | Thomas Z. Ward
Source: arXiv (Cornell University) (preprint, 2024-12-13)
Field: Materials Science — Materials Chemistry

Polarization rotation in a ferroelectric BaTiO$_3$ film through\n low-energy He-implantation Domain engineering in ferroelectric thin films is crucial for next-generation\nmicroelectronic and photonic technologies. Here, a method is demonstrated to\nprecisely control domain configurations in BaTiO$_3$ thin films through\nlow-energy He ion implantation. The approach transforms a mixed ferroelectric\ndomain state with significant in-plane polarization into a uniform out-of-plane\ntetragonal phase by selectively modifying the strain state in the film's top\nregion. This structural transition significantly improves domain homogeneity\nand reduces polarization imprint, leading to symmetric ferroelectric switching\ncharacteristics. The demonstrated ability to manipulate ferroelectric domains\npost-growth enables tailored functional properties without compromising the\ncoherently strained bottom interface. The method's compatibility with\nsemiconductor processing and ability to selectively modify specific regions\nmake it particularly promising for practical implementation in integrated\ndevices. This work establishes a versatile approach for strain-mediated domain\nengineering that could be extended to a wide range of ferroelectric systems,\nproviding new opportunities for memory, sensing, and photonic applications\nwhere precise control of polarization states is essential.\n Ferroelectricity ; Polarization (electrochemistry) ; Materials science ; Rotation (mathematics) ; Low energy ; Condensed matter physics ; Optoelectronics ; Dielectric ; Physics ; Atomic physics ; Chemistry ; Computer science Ferroelectric and Piezoelectric Materials ; Acoustic Wave Resonator Technologies ; Surface Roughness and Optical Measurements