jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Volodymyr Svitlyk | Luíza Braga Ferreira dos Santos | Jonas Nießen | Sara E. Gilson | Julien Marquardt | Stefan Findeisen | Selina Richter | Shavkat Akhmadaliev | Nina Huittinen | Christoph Hennig
Source: Journal of Synchrotron Radiation (article, 2024-02-16)
Field: Materials Science — Materials Chemistry

Grazing-incidence synchrotron radiation diffraction studies on irradiated Ce-doped and pristine Y-stabilized ZrO<sub>2</sub> at the Rossendorf beamline In this work, Ce-doped yttria-stabilized zirconia (YSZ) and pure YSZ phases were subjected to irradiation with 14 MeV Au ions. Irradiation studies were performed to simulate long-term structural and microstructural damage due to self-irradiation in YSZ phases hosting alpha-active radioactive species. It was found that both the Ce-doped YSZ and the YSZ phases had a reasonable tolerance to irradiation at high ion fluences and the bulk crystallinity was well preserved. Nevertheless, local microstrain increased in all compounds under study after irradiation, with the Ce-doped phases being less affected than pure YSZ. Doping with cerium ions increased the microstructural stability of YSZ phases through a possible reduction in the mobility of oxygen atoms, which limits the formation of structural defects. Doping of YSZ with tetravalent actinide elements is expected to have a similar effect. Thus, YSZ phases are promising for the safe long-term storage of radioactive elements. Using synchrotron radiation diffraction, measurements of the thin irradiated layers of the Ce-YSZ and YSZ samples were performed in grazing incidence (GI) mode. A corresponding module for measurements in GI mode was developed at the Rossendorf Beamline and relevant technical details for sample alignment and data collection are also presented. Materials science ; Irradiation ; Yttria-stabilized zirconia ; Crystallinity ; Doping ; Beamline ; Cubic zirconia ; Cerium ; Analytical Chemistry (journal) ; Radiochemistry ; Composite material ; Optics ; Optoelectronics ; Metallurgy ; Chemistry Nuclear materials and radiation effects ; Nuclear Materials and Properties ; Fusion materials and technologies
Authors: Robert Toews | Andreas Köhn
Source: Physical Chemistry Chemical Physics (article, 2024-01-01)
Field: Chemistry — Organic Chemistry

Cyclohepta[<i>def</i>]fluorene as a bistable molecule: first principles studies on its electronic structure and the effects of benzo-extension, substitution and solvation Cyclohepta[<i>def</i>]fluorene 1 and its derivatives have received considerable attention due to possible technological applications as molecular devices. Despite efforts from both theory and experiment, the electronic structure of 1 has remained unclear. Herein, we report advanced first-principles calculations on 1 using a multireference and a coupled-cluster method. We confirm a bistability of 1 between a polar singlet state and a non-polar triplet state. We also study the effects of benzo-extension on the electronic structure and the influences of substitution and solvation on the ground state. Our results suggest that deliberate choice of substituents allows to toggle the multiplicity of the ground state. We also propose that due to its bistability, 1 represents an attractive building block for molecular devices. Bistability ; Substitution (logic) ; Extension (predicate logic) ; Solvation ; Electronic structure ; Molecule ; Chemistry ; Computational chemistry ; Physics ; Computer science ; Quantum mechanics ; Organic chemistry Synthesis and Properties of Aromatic Compounds ; Cyclopropane Reaction Mechanisms ; Axial and Atropisomeric Chirality Synthesis
Authors: Arram Madhavi | Medidi Srinivas | Niraj Gupta
Source: International Journal of Pharmaceutical Investigation (article, 2024-07-01)
Field: Chemistry — Analytical Chemistry

Development of a Robust and Reliable RP-HPLC Method for the Estimation of Vericiguat in Tablet Dosage Form: Greenness Analysis using AGREE Penalties Arram Madhavi12, Medidi Srinivas1 and Niraj Gupta2 Author informationCitations 1Department of Pharmaceutical Chemistry, Geethanjali College of Pharmacy, Cheeryal, Keesara, Medchal, Hyderabad, Telangana, INDIA 2Department of Pharmaceutical Chemistry, School of Pharmacy, OPJS University, Rawatsar Kunjla, Near Sankhu Fort, Rajgarh (Sadulpur), Jhunjhunu Road, Churu, Rajasthan, INDIA Corresponding author. Correspondence: Prof. Medidi Srinivas Department of Pharmaceutical Chemistry, Geethanjali Computer science ; Estimation ; Dosage form ; Chromatography ; Biological system ; Biochemical engineering ; Chemistry ; Biology Analytical Methods in Pharmaceuticals ; Analytical Chemistry and Chromatography ; Crystallization and Solubility Studies
Authors: Yannick Anguy | Margaux Haurat | Michel Dumon
Source: Small (article, 2024-12-23)
Field: Materials Science — Polymers and Plastics

The Quest for Contrast in Digital Images of Micro/Nano Structured Polymer Blends Before and After CO<sub>2</sub> Foaming: Impact of Block Copolymer Content and Size Upon Acrylic Cellular Structures This work addresses the structural quantification of multiphase materials, here nanostructured polymer solid precursors and their micro/nano sized foamed counterparts. It is based on a strategy of contrast/edge enhancement, locally adaptive to image data in digital images of materials. The method allows to binarize straightforwardly the structures (the phases) in TEM and SEM images after edge identification, edge choice, and image virtual reconstruction. A detailed insight is brought into one-step batch supercritical CO<sub>2</sub> foaming of acrylic amorphous PMMA (polymethyl methacrylate) polymers, aided by the nanostructuration of block copolymers (BCP), here MAM (butyl acrylate center block methyl acrylate side blocks). The foaming conditions, i.e., pressure drop rate (PDR) and saturation temperature required for an actual one-step procedure are specified and clarified, whereas previous works, dealing with "one-step procedures", are probably incurring in a two-step procedure. The roles of the BCP content (and size) and saturation temperature are carefully analyzed and further clarified, more comprehensively than in previous literature. Thanks to the analysis of size distributions of foams and foam blend precursors (0.25, 0.5, 10 wt% MAM), bi modality of 10 wt% foams is for example revealed. A discussion of kinetics effects, i.e., evolutions of the effective sample temperature T<sub>ef</sub>(t), and the effective glass transition temperature T<sub>g, ef</sub>(t). provides a new insight of "pseudo" one-step VS "real" one-step batch foaming. Materials science ; Copolymer ; Polymer ; Acrylate ; Composite material ; Digital image ; Chemical engineering ; Computer science ; Image processing Polymer Foaming and Composites ; Phase Equilibria and Thermodynamics ; Injection Molding Process and Properties
Authors: Ryuichi Ando | K. Sugawara | Tappei Kawakami | T. Takahashi | T. Sato
Source: Journal of the Physical Society of Japan (article, 2024-07-11)
Field: Materials Science — Materials Chemistry

Selective Fabrication of Monolayer 1<i>H</i>- and 1<i>T</i>′-WTe<sub>2</sub> We selectively fabricated monolayers of octahedral (1H) and distorted trigonal (1T') WTe2 on graphene/SiC(0001) by controlling the substrate temperature during epitaxy. Angle-resolved photoemission spectroscopy, combined with first-principles band-structure calculations, has revealed several drastic differences between these two polymorphs. The 1T' phase exhibits a semiconducting character with a nearly-zero energy gap, while the 1H phase shows a large band gap and the band splitting at the K/K' point. The present results pave a pathway toward developing nanoelectronic devices based with WTe2. Monolayer ; Fabrication ; Materials science ; Nanotechnology 2D Materials and Applications ; MXene and MAX Phase Materials ; Advanced Thermoelectric Materials and Devices
Authors: Katharina Nisi | John C. Thomas | Sergej Levashov | Elmar Mitterreiter | Takashi Taniguchi | Kenji Watanabe | Shaul Aloni | Tevye Kuykendall | Johanna Eichhorn | Alexander W. Holleitner | Alexander Weber‐Bargioni | Christoph Kastl
Source: 2D Materials (article, 2024-12-17)
Field: Materials Science — Materials Chemistry

Scanning probe spectroscopy of sulfur vacancies and MoS<sub>2</sub> monolayers in side-contacted van der Waals heterostructures Abstract We investigate the interplay between vertical tunneling and lateral transport phenomena in electrically contacted van der Waals heterostructures made from monolayer MoS 2 , hBN, and graphene. We compare data taken by low-temperature scanning tunneling spectroscopy to results from room-temperature conductive atomic force spectroscopy on monolayer MoS 2 with sulfur vacancies and with varying hBN layers. We show that for thick hBN barrier layers, where tunneling currents into the conductive substrate are suppressed, a side-contact still enables addressing the defect states in the scanning tunneling microscopy via the lateral current flow. Few-layer hBN realizes an intermediate regime in which the competition between vertical tunneling and lateral transport needs to be considered. The latter is relevant for device structures with both a thin tunneling barrier and a side-contact to the semiconducting layers. Monolayer ; Scanning tunneling spectroscopy ; Quantum tunnelling ; van der Waals force ; Scanning tunneling microscope ; Heterojunction ; Condensed matter physics ; Materials science ; Substrate (aquarium) ; Spectroscopy ; Graphene ; Nanotechnology ; Chemical physics ; Chemistry ; Optoelectronics ; Physics ; Molecule 2D Materials and Applications ; Graphene research and applications ; Molecular Junctions and Nanostructures
Authors: Haosong Ying | Binbin Wei | Qing Zang | Jiduo Dong | Hao Zhang | Hao Tian | Chunheng Liu | Yang Liu
Source: Nanomaterials (article, 2024-10-16)
Field: Materials Science — Materials Chemistry

Electrical Transport Properties of PbS Quantum Dot/Graphene Heterostructures The integration of PbS quantum dots (QDs) with graphene represents a notable advancement in enhancing the optoelectronic properties of quantum-dot-based devices. This study investigated the electrical transport properties of PbS quantum dot (QD)/graphene heterostructures, leveraging the high carrier mobility of graphene. We fabricated QD/graphene/SiO<sub>2</sub>/Si heterostructures by synthesizing p-type monolayer graphene via chemical vapor deposition and spin-coating PbS QDs on the surface. Then, we used a low-temperature electrical transport measurement system to study the electrical transport properties of the heterostructure under different temperature, gate voltage, and light conditions and compared them with bare graphene samples. The results indicated that the QD/graphene samples exhibited higher resistance than graphene alone, with both resistances slightly increasing with temperature. The QD/graphene samples exhibited significant hole doping, with conductivity increasing from 0.0002 Ω<sup>-1</sup> to 0.0007 Ω<sup>-1</sup> under gate voltage modulation. As the temperature increased from 5 K to 300 K, hole mobility decreased from 1200 cm<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup> to 400 cm<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup> and electron mobility decreased from 800 cm<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup> to 200 cm<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup>. Infrared illumination reduced resistance, thereby enhancing conductivity, with a resistance change of about 0.4%/mW at a gate voltage of 125 V, demonstrating the potential of these heterostructures for infrared photodetector applications. These findings offer significant insights into the charge transport mechanisms in low-dimensional materials, paving the way for high-performance optoelectronic devices. Graphene ; Materials science ; Heterojunction ; Quantum dot ; Optoelectronics ; Electron mobility ; Chemical vapor deposition ; Nanotechnology Graphene research and applications ; Quantum Dots Synthesis And Properties ; Graphene and Nanomaterials Applications
Authors: Daniel Qvarngård | P. Henelius
Source: Physical review. B./Physical review. B (article, 2024-09-09)
Field: Materials Science — Materials Chemistry

Classical spin models and basic magnetic interactions on 1/1-approximant crystals We study classical spin models on the 1/1 Tsai-type approximant lattice using Monte Carlo and mean-field methods. Our aim is to understand whether the phase diagram differences between Gd- and Tb-based approximants can be attributed to anisotropy induced by the crystal-electric field. To address this question, we treat Gd ions as Heisenberg spins and Tb ions as Ising spins. Additionally, we consider the presence of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction to replicate the experimentally observed correlation between magnetic properties and electron concentration. Surprisingly, our findings show that the transition between ferromagnetic and antiferromagnetic order remains unaltered by the anisotropy, even when accounting for the dipole interaction. We conclude that a more comprehensive model, extending beyond the free-electron gas RKKY interaction, is likely required to fully understand the distinctions between Gd- and Tb-based approximants. Our work represents a systematic exploration of the impact of anisotropy on the ground-state properties of classical spin models in quasicrystal approximants. Published by the American Physical Society 2024 Spin (aerodynamics) ; Condensed matter physics ; Padé approximant ; Physics ; Theoretical physics ; Mathematics ; Mathematical analysis ; Thermodynamics Quasicrystal Structures and Properties ; X-ray Diffraction in Crystallography ; Magnetic properties of thin films
Authors: Vladimir Ya. Lee | Junkang Wang | Takahiro Sasamori | Olga A. Gapurenko | Ruslan M. Minyaev | Владимир И. Минкин | Katsuhiko Takeuchi | Norihisa Fukaya | Heinz Gornitzka
Source: Chemistry - A European Journal (article, 2024-05-24)
Field: Chemistry — Inorganic Chemistry

Electrophilic Behavior of the “Nucleophilic” Pyramidane: Reactivity of Ge‐Pyramidane towards Organolithium Reagents The particular reactivity of the recently discovered class of the main group element polyhedral clusters, pyramidanes, remains largely unexplored. In this communication, we report the reaction of the germapyramidane with tert-butyllithium leading to the rather unusual organogermanium compound [Li<sup>+</sup>(thf)<sub>2</sub>]⋅2<sup>-</sup>, as the product of the formal insertion of a Ge-apex into the C-Li bond. This reactivity mode exemplifies unusual electrophilic behaviour of a pyramidane, which is a priori considered as a nucleophilic reagent. Being highly reactive, [Li<sup>+</sup>(thf)<sub>2</sub>]⋅2<sup>-</sup> readily undergoes reactions with electrophiles (MeI, EtBr), initially forming intermediate germahousenes, which isomerize to the thermodynamically more favourable germoles. Reactivity (psychology) ; Nucleophile ; Electrophile ; Reagent ; Butyllithium ; Chemistry ; Combinatorial chemistry ; Organic chemistry ; Catalysis ; Medicine Synthesis and characterization of novel inorganic/organometallic compounds ; Organoboron and organosilicon chemistry ; Coordination Chemistry and Organometallics
Authors: Salvatore Cianci | Elena Blundo | Marco Felici
Source: Nano Futures (article, 2024-02-12)
Field: Materials Science — Materials Chemistry

One (photon), two(-dimensional crystals), a lot (of potential): a quick snapshot of a rapidly evolving field Abstract We present a concise overview of the state of affairs in the development of single-photon sources based on two-dimensional (2D) crystals, focusing in particular on transition-metal dichalcogenides and hexagonal boron nitride. We briefly discuss the current level of advancement ( i ) in our understanding of the microscopic origin of the quantum emitters (QEs) identified in these two material systems, and ( ii ) in the characterisation of the optical properties of these emitters; then, we survey the main methods developed to enable the dynamic control of the QEs’ emission energy. Finally, we summarise the main results stemming from the coupling of QEs embedded in 2D materials with photonic and plasmonic structures. Snapshot (computer storage) ; Photon ; Field (mathematics) ; Physics ; Computer science ; Optics ; Theoretical physics ; Mathematics ; Pure mathematics ; Database 2D Materials and Applications ; Perovskite Materials and Applications ; Graphene research and applications
Authors: Yizhen Wang | Jianping Yin | Xuepeng Zhang | Jianya Yi | Xudong Li
Source: Scientific Reports (article, 2024-12-28)
Field: Materials Science — Materials Chemistry

Study on jet dynamic impact performance under the influence of standoff Due to the sensitivity of the shaped charge jet to standoff and the complexity of its impact under lateral disturbances, this study aims to investigate the dynamic impact evolution of the jet influenced by standoff and lateral disturbances. A finite element model for the dynamic impact of shaped charge jets was established. Dynamic impact experiments were designed and conducted to validate the effectiveness of the numerical simulations. Utilizing dimensional analysis, a predictive model was developed for jet dynamic impact considering the combined effects of target plate strength, standoff and lateral disturbances. The results indicate that as the standoff varies between 90 mm and 225 mm, the dynamic impact depth of the jet decreases approximately linearly with increasing standoff. Meanwhile, for lateral disturbance velocities ranging from 100 m/s to 400 m/s, the impact depth decreases exponentially with increasing lateral relative velocity of the target. The lateral disturbance velocity is identified as the primary factor influencing jet impact, while the standoff is a secondary factor. The agreement among computational results, numerical simulations, and experimental outcomes confirms the accuracy and effectiveness of the predictive model and simulations, providing a basis for evaluating the dynamic impact potential of shaped charges. Jet (fluid) ; Mechanics ; Shaped charge ; Computer simulation ; Sensitivity (control systems) ; Structural engineering ; Materials science ; Physics ; Engineering ; Chemistry High-Velocity Impact and Material Behavior ; Fluid Dynamics Simulations and Interactions ; Laser-Plasma Interactions and Diagnostics
Authors: Sandra Benter | Marco Bianchi | Dong Pan | Jianhua Zhao | H. Q. Xu | Rainer Timm | Philip Hofmann | Anders Mikkelsen
Source: Applied Physics Letters (article, 2024-04-08)
Field: Materials Science — Materials Chemistry

2D electron gas formation on InAs wurtzite nanosheet surfaces The two-dimensional electron gas (2DEG) that forms on a semiconductor surface can be used to explore a variety of phenomena in quantum physics and plays an important role in nanoscale electronics, such as transistors. Controlling its formation is, thus, relevant. Using angle-resolved photoemission spectroscopy (ARPES) and accumulating the signal over many nanocrystals, we find that on clean InAs nanosheets with non-polar surfaces and wurtzite (WZ) crystal structures, a 2DEG can be observed at the Γ-point. We suggest that the step morphology on the WZ InAs specimens facilitates the appearance of the electron gas, since previous studies on InAs nanowire surfaces with the same crystal facet and a similar defect density did not exhibit a 2DEG. Subsequently, bismuth deposition leads to the disappearance of the 2DEG as well as a shift of the valence band. This is in contrast to previous observations on InAs surfaces, in which metal deposition would lead to the formation of a 2DEG. The control of the 2DEG with the addition of Bi atoms is relevant for applications of InAs nanosheets in quantum technologies. This study also illustrates that ARPES accumulated over several 2D materials oriented randomly around their normal axis can provide valuable information on their band structure with a fast turnover and low irradiation. Wurtzite crystal structure ; Angle-resolved photoemission spectroscopy ; Materials science ; Fermi gas ; Bismuth ; Nanowire ; Semiconductor ; Condensed matter physics ; Nanotechnology ; Quantum dot ; Electron ; Electronic structure ; Optoelectronics ; Physics ; Zinc Electronic and Structural Properties of Oxides ; Semiconductor materials and devices ; Advanced Semiconductor Detectors and Materials
Authors: Tristan da Câmara Santa Clara Gomes | Nicolas Marchal | Joaquín de la Torre Medina | Flavio Abreu Araujo | Luc Piraux
Source: Applied Physics Letters (article, 2024-02-26)
Field: Materials Science — Materials Chemistry

Thermoelectric and magneto-transport characteristics of interconnected networks of ferromagnetic nanowires and nanotubes Macroscopic-scale nanostructures, situated at the interface of nanostructures and bulk materials, hold significant promise in the realm of thermoelectric materials. Nanostructuring presents a compelling avenue for enhancing material thermoelectric performance as well as unlocking intriguing nanoscale phenomena, including spin-dependent thermoelectric effects. This is achieved while preserving high power output capabilities and ease of measurements related to the overall macroscopic dimensions. Within this framework, the recently developed three-dimensional interconnected nanowire and nanotube networks, integrated into a flexible polymer membrane, emerge as promising candidates for macroscopic nanostructures. The flexibility of these composites also paves the way for advances in the burgeoning field of flexible thermoelectrics. In this study, we demonstrate that the three-dimensional nanowire networks made of ferromagnetic metals maintain the intrinsic bulk thermoelectric power of their bulk constituent even for a diameter reduced to approximately 23 nm. Furthermore, we showcase the pioneering magneto-thermoelectric measurements of three-dimensional interconnected nickel nanotube networks. These macroscopic materials, comprising interconnected nanotubes, enable the development of large-area devices that exhibit efficient thermoelectric performance, while their nanoscale tubular structures provide distinctive magneto-transport properties. This research represents a significant step toward harnessing the potential of macroscopic nanostructured materials in the field of thermoelectrics. Thermoelectric effect ; Materials science ; Thermoelectric materials ; Nanowire ; Nanotechnology ; Seebeck coefficient ; Nanostructure ; Thermoelectric generator ; Carbon nanotube ; Ferromagnetism ; Engineering physics ; Condensed matter physics ; Thermal conductivity ; Composite material ; Physics Advanced Thermoelectric Materials and Devices ; Thermal properties of materials ; Thermal Radiation and Cooling Technologies