jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Tao Lu | Fan Xie | Nathan A. Seifert | Reihaneh Hamidi Mejlej | Wolfgang Jäger | Yunjie Xu
Source: Physical Chemistry Chemical Physics (article, 2024-01-01)
Field: Chemistry — Spectroscopy

Binary conformers of a flexible, long-chain fluoroalcohol: dispersion controlled selectivity and relative abundances in a jet The complex conformational panorama of binary 4,4,4-trifluoro-1-butanol (TFB) aggregates was investigated using chirped-pulse Fourier transform microwave spectroscopy, aided by conformational searches using CREST (Conformer-Rotamer Ensemble Sampling Tool) and quantum chemistry calculations. From nearly 1500 initial dimer geometries, 16 most stable binary candidates were obtained within a relative energy window of ∼4 kJ mol<sup>-1</sup>. Rotational spectra of five binary conformers were experimentally observed in supersonic expansion and assigned. Interestingly, three out of the five observed binary conformers are composed solely of monomer conformers, which were not observed in their isolated gas phase forms in jet expansion. In addition, an observed dimer that is made exclusively of the most stable TFB monomer subunits does not correspond to the global minimum. The intricate kinetically and thermodynamically controlled dimer formation mechanisms are discussed, and a modified kinetic-thermodynamic model was developed, providing conformational abundances that are in good agreement with the experiment. Subsequent non-covalent interaction analyses reveal that the observed conformers are held together by one primary O-H⋯O hydrogen bond and secondary intermolecular C-H⋯O, C-H⋯F, and/or O-H⋯F interactions, as well as C-H⋯H-C London dispersion interactions between the methylene groups. Further symmetry-adapted perturbation theory analyses of the TFB dimer conformers and related alcohol dimers reveal a considerable rise in dispersion contributions with increasing <i>n</i>-alkyl carbon chain length and highlight the role of dispersion interactions in preferentially stabilizing the global minimum of the TFB dimer. Conformational isomerism ; Dimer ; Chemistry ; Crystallography ; Molecule ; Organic chemistry Molecular Spectroscopy and Structure ; Advanced Chemical Physics Studies ; Spectroscopy and Laser Applications
Authors: Anhao Jiang | Chaohai Zhang | Min Zhu | Xiaoxing Zhang
Source: High Voltage (article, 2024-12-18)
Field: Chemistry — Spectroscopy

Detection of characteristic component H <sub>2</sub> S in SF <sub>6</sub> and SF <sub>6</sub> /N <sub>2</sub> mixture using cavity ring‐down spectroscopy Abstract A high‐sensitivity cavity ring‐down spectroscopy gas detection system with integrated optical components and embedded microprocessor units is presented for the detection of hydrogen sulfide (H 2 S) in sulphur hexafluoride (SF 6 ) and its mixture with nitrogen (N 2 ). The system exploits a periodic laser wavelength modulation to simplify the mode matching. Spectral line profile fitting is used for sample quantitative analysis. To verify the sensitivity and stability of concentration detection, the effect of background gas and temperature on the responses of spectral line broadening and absorption cross‐section are investigated. The result deviation caused by variation of background gas can be compensated by the pre‐correction of empty cavity ring‐down time. It is also found that the implication of temperature on the spectra cannot be ignored. The full width at half maximum and peak value decreased linearly with the increase of temperature, while the baseline is undergoing accelerated growth. Using Allan variance analysis, the limits of detection reach 4.44 × 10 −9 in SF 6 and 2.96 × 10 −9 in N 2 with average time of 67 s. This study provides a meaningful approach for the online detection of characteristic gas in gas insulation equipment. Cavity ring-down spectroscopy ; Spectroscopy ; Component (thermodynamics) ; Ring (chemistry) ; Analytical Chemistry (journal) ; Materials science ; Chemistry ; Physics ; Chromatography ; Organic chemistry ; Thermodynamics Spectroscopy and Laser Applications ; Mass Spectrometry Techniques and Applications ; Atmospheric Ozone and Climate
Authors: Satoshi Semboshi | Ryusei Arauchi | Yasuyuki Kaneno | Sung Hwan Lim | Eun‐Ae Choi | Seung Zeon Han
Source: Metallurgical and Materials Transactions A (article, 2024-09-06)
Field: Materials Science — Materials Chemistry

Microstructure and Mechanical Properties of Low Stacking-Fault Energy Cu-Based Alloy Wires Abstract Innovations in electronic devices and their capabilities have driven the demand for improved conductive materials relevant to device fabrication. To gain insights on developing solid solution-type Cu alloy thin wires with a superior balance of strength and conductivity, this study investigated variations in the microstructures and properties of pure Cu wires and Cu–5 at. pct Zn, Cu–5 at. pct Al, and Cu–5 at. pct In alloy wires during intense drawing and analyzed the effects of stacking-fault energy (SFE) of Cu alloys on their microstructural evolution. During the initial drawing stages, lower SFE Cu–5 at. pct Al and Cu–5 at. pct In alloys yielded more high-density deformation twins than pure Cu and Cu–5 at. pct Zn. Deformation twins promoted grain refinement during drawing. Effective grain refinement and dislocation accumulation during drawing in low-SFE Cu alloys substantially strengthened them without adversely impacting electrical conductivity. During intense drawing in the Cu–5 at. pct In alloy wires, ultrafine fibrous grains (diameter ~ 80 nm) and a high-dislocation density yielded excellent tensile strength and conductivity. These results indicate that adjusting the solute element content in Cu matrix to reduce SFE and optimizing deformation strain via wire drawing significantly improve alloy wire performance. Microstructure ; Stacking-fault energy ; Alloy ; Materials science ; Stacking ; Metallurgy ; Stacking fault ; Composite material ; Dislocation ; Chemistry Microstructure and mechanical properties ; Aluminum Alloys Composites Properties ; Aluminum Alloy Microstructure Properties
Authors: Alex Shaji | Kevin J. Rietwyk | Islay O. Robertson | Philipp Reineck | David A. Broadway | Jean‐Philippe Tetienne
Source: Advanced Sensor Research (article, 2024-08-05)
Field: Materials Science — Materials Chemistry

A Compact, Portable Device for Microscopic Magnetic Imaging Based on Diamond Quantum Sensors Abstract Magnetic imaging based on ensembles of diamond nitrogen‐vacancy quantum sensors has emerged as a useful technique for the spatial characterization of magnetic materials and current distributions. However, demonstrations have so far been restricted to laboratory‐based experiments using relatively bulky apparatus and requiring manual handling of the diamond sensing element, hampering broader adoption of the technique. Here a simple, compact device that can be deployed outside a laboratory environment and enables robust, simplified operation is presented. It relies on a specially designed sensor head that directly integrates the diamond sensor while incorporating a microwave antenna and all necessary optical components. This integrated sensor head is complemented by a small control unit and a laptop computer that displays the resulting magnetic image. The device is tested by imaging a magnetic sample, demonstrating a spatial resolution of 4 µm over a field of view exceeding 1 mm, and a best sensitivity of 45 µT per (5 µm) 2 pixel. The portable magnetic imaging instrument may find use in situations where taking the sample to be measured to a specialist lab is impractical or undesirable. Diamond ; Optoelectronics ; Quantum sensor ; Materials science ; Quantum ; Nanotechnology ; Physics ; Quantum computer ; Quantum simulator ; Quantum mechanics ; Composite material Diamond and Carbon-based Materials Research ; Atomic and Subatomic Physics Research ; Carbon Nanotubes in Composites
Authors: Florian Johst | Jannik Rebmann | Hans Werners | Lars Klemeyer | Jagadesh Kopula Kesavan | Dorota Koziej | Christian Strelow | Gabriel Bester | Alf Mews | Tobias Kipp
Source: ACS Photonics (article, 2024-09-06)
Field: Materials Science — Materials Chemistry

Exciton–Phonon Coupling in Single ZnCdSe-Dot/CdS-Rod Nanocrystals with Engineered Band Gaps from Type-II to Type-I Exciton-phonon coupling limits the homogeneous emission line width of nanocrystals. Hence, a full understanding of this is crucial. In this work, we statistically investigate exciton-phonon coupling by performing single-particle spectroscopy on colloidal Zn<sub>1-<i>x</i></sub> Cd <sub><i>x</i></sub> Se/CdS and CdSe/CdS dot-in-rod nanocrystals at cryogenic temperatures (<i>T</i> ≈ 10 K). In situ cation exchange enables us to analyze different band alignments and, thereby, different charge-carrier distributions. We find that the relative intensities of the longitudinal optical S- and Se-type phonon replicas correlate with the charge-carrier distribution. Our experimental findings are complemented with quantum mechanical calculations within the effective mass approximation that hint at the relevance of surface charges. Exciton ; Nanocrystal ; Phonon ; Quantum dot ; Materials science ; Coupling (piping) ; Biexciton ; Spectroscopy ; Colloid ; Condensed matter physics ; Homogeneous ; Optoelectronics ; Molecular physics ; Nanotechnology ; Physics ; Chemistry ; Physical chemistry ; Quantum mechanics Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; Carbon and Quantum Dots Applications
Authors: C.R.H. Bahl | Kurt Engelbrecht | Arendse Gideon | Mikael Alexander Vinogradov Levy | Jacob Birkjær Marcussen | Carlos Imbaquingo | Rasmus Bjørk
Source: Applied Energy (article, 2024-08-26)
Field: Materials Science — Materials Chemistry

Design, optimization and operation of a high power thermomagnetic harvester Converting low temperature waste heat to electricity is vital for the green transition. Here we present how to design and optimize a thermomagnetic energy harvester that can convert a stream of waste heat to electricity through Faradays law. In optimizing the design in the traditional figure-of-eight shape, we determine the ideal size of the magnet and the beds of magnetic material using a numerical model given an overall volume constraint for each of the thermomagnetic volumes of 20 cm 3 . The magnet is determined to ideally be 5 × 5 × 1 . 25 cm, the beds should have a height of 1.09 cm and contain about 120 g of Gd spheres, and we use coils with a wire diameter of 1.8 mm and 156 windings in each coil. Following the design study, the system is realized using off-the-shelf components and tested as a function of flow rate, frequency of operation and temperature span. At a temperature span of 40 °C and a hot side temperature of 40 °C, the device produces 9 mW of power at a flow rate of 1.4 L/min. • We design an optimal thermomagnetic/magnetothermal energy harvester. • Using a model the ideal size and shape of magnet and magnetic beds are determined. • The device is subsequently realized using off-the-shelf components. • The device is tested as function of flow rate, frequency and temperature span. • At a temperature span of 40 °C and 1.4 L/min. the device produce 9 mW Thermomagnetic convection ; Power (physics) ; Automotive engineering ; Engineering ; Electrical engineering ; Mechanical engineering ; Computer science ; Physics ; Magnetic field Advanced Thermoelectric Materials and Devices ; Advanced Thermodynamic Systems and Engines ; Innovative Energy Harvesting Technologies
Authors: Jorge Olmos‐Trigo | Hiroshi Sugimoto | Minoru Fujii
Source: Laser & Photonics Review (article, 2024-01-20)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Far‐Field Detection of Near‐Field Circular Dichroism Enhancements Induced by a Nanoantenna Abstract Nanophotonics can enhance the inherent weak signal exhibited by chiral molecules in circular dichroism (CD) spectroscopy experiments. One mechanism to achieve this CD enhancement is based on increasing the optical chirality produced by nanophotonics antennas in their near‐field, where chiral molecules are placed. However, ascertaining whether this CD enhancement is reached presents significant experimental challenges due to the complexity of measuring near‐field optical chirality. Here, it is demonstrated that a local and single measurement of the degree of circular polarization in the far‐field enables quantifying near‐field CD enhancements. Thereby, based on this far‐field measurement, the optimal response of the antenna is predicted for enhanced chiral sensing. Experimental validation of this near‐to‐far‐field relation is provided for silicon spherical nanoantennas. The experimental results, supported by analytical theory and exact numerical simulations, can be interesting for the experimental characterization of devices capable of enhancing CD from a single far‐field Stokes measurement. Circular dichroism ; Nanophotonics ; Near and far field ; Chirality (physics) ; Circular polarization ; Polarization (electrochemistry) ; Field (mathematics) ; Electromagnetic field ; Stokes parameters ; Optics ; Physics ; Optoelectronics ; Materials science ; Chemistry ; Scattering ; Chiral symmetry Metamaterials and Metasurfaces Applications ; Plasmonic and Surface Plasmon Research ; Orbital Angular Momentum in Optics
Authors: Bárbara Schmitz‐Abecassis | Chloé Najac | Jaimy Plugge | Matthias J.P. van Osch | Ece Ercan
Source: NMR in Biomedicine (article, 2024-01-23)
Field: Materials Science — Materials Chemistry

Investigation of metabolite correlates of CEST in the human brain at 7 T Metabolite-weighted chemical exchange saturation transfer MRI can be used to indirectly image metabolites such as creatine and glutamate. This study aims to further explore the contrast of CEST at 2 ppm in the human brain at 7T and investigate the metabolite correlates of CEST at 2 ppm via correlations with magnetic resonance spectroscopy (MRS). Simulations were performed to establish the optimal acquisition parameters, such as total saturation time (t<sub>sat</sub>) and B<sub>1</sub> root mean squared (B<sub>1</sub>rms) for CEST at 2 ppm in the human brain. Parameters were validated via in vitro phantom studies at 7T using concentrations, pH and temperature comparable to what is found in the human brain. Finally, 10 healthy volunteers were scanned at 7T for comparison with MRS. Our results show that the optimal parameters to acquire CEST at 2 ppm images are: B<sub>1</sub>rms = 2.14 μT & t<sub>sat</sub> = 1500 ms, respectively. Comparison with MRS showed no significant correlation between CEST at 2 ppm and total Creatine measured by MRS (R = 0.19; p-value = 0.273). However, a significant correlation was found between CEST at 2 ppm and Glu (R = 0.39; p-value = 0.033), indicating the broad Glutamate-weighted CEST as the main measurable contributor to CEST at 2 ppm. We identified and confirmed optimal CEST at 2 ppm sequence parameters and validated CEST at 2 ppm measurements in a controlled in vitro environment. Our findings suggest that glutamate is a substantial contributor to the CEST at 2 ppm contrast observed in the human brain, whereas the creatine contribution to CEST at 2 ppm in the brain did not show a measurable contribution. Metabolite ; Creatine ; Chemistry ; Nuclear magnetic resonance ; Human brain ; Magnetic resonance imaging ; Glutamate receptor ; In vivo magnetic resonance spectroscopy ; Nuclear medicine ; Medicine ; Biochemistry ; Physics ; Radiology Lanthanide and Transition Metal Complexes ; Advanced MRI Techniques and Applications ; Radioactive element chemistry and processing
Authors: Samuel López-Blanco | Xavier Vendrell | Nerea Morante | José E. García
Source: Journal of Materials Chemistry C (article, 2024-12-27)
Field: Materials Science — Materials Chemistry

High performance BaTiO<sub>3</sub>–SrTiO<sub>3</sub> ceramics with refined microstructure obtained by current-controlled reactive flash sintering of mixed powders Current-controlled flash sintering has been demonstrated to be a powerful tool for microstructural engineering in dielectric materials, providing new pathways for developing energy-efficient storage systems through enhanced electrical homogeneity. Materials science ; Microstructure ; Sintering ; Flash (photography) ; Ceramic ; Current (fluid) ; Composite material ; Metallurgy ; Mineralogy ; Optics ; Thermodynamics Ferroelectric and Piezoelectric Materials ; Microwave Dielectric Ceramics Synthesis ; Magnesium Oxide Properties and Applications
Authors: Ilyas Khurshid | Muritala Alade Amidu | Mubashir Hassan | M. Faizan | Imran Afgan | Yacine Addad
Source: Arabian Journal for Science and Engineering (article, 2024-07-29)
Field: Materials Science — Materials Chemistry

A Thermal Approach for Modeling Concrete Ablation During Molten Corium–Concrete Interaction Abstract An accident in a nuclear power plant involving a reactor core meltdown could result in the instigation of molten corium, which is a mixture of nuclear fuel, claddings and structural components. In this paper, an enthalpy-porosity model is proposed to comprehensively analyze the ablation of concrete during the molten corium and concrete interaction process. The developed numerical model is an extension of the enthalpy-porosity model and is termed the CCEPM. The developed CCEPM computational fluid dynamics model can predict natural convection, melting and solidification. The developed model simplifies the complex phenomena of concrete ablation and melting by incorporating the multiregional approach. The model was implemented in OpenFOAM by developing a new solver that couples buoyant-driven natural convection and conjugate heat transfer solvers. The thermal modeling and heat transfer capabilities of the developed solver were verified against experimental data sets. Additionally, the effects of various boundary conditions, concrete thermal conductivities and decay heat intensities were analyzed to study their impacts on concrete ablation. We observed significant low concrete ablation and controlled temperature and velocity fields for the water-cooled boundary condition. Accordingly, the ablation of concrete decreased by 17% by imposing the water-cooled boundary condition. Similarly, when the thermal conductivity of concrete was decreased to 0.43 and 0.13 W/m.K, the ablation of the concrete decreased by 38% and 75%, respectively. Furthermore, early cooling of molten corium to decrease the decay heat was found to be an effective strategy for successfully mitigating concrete ablation by 20%. Corium ; Materials science ; Heat transfer ; Thermal conductivity ; Porosity ; Natural convection ; Thermal ; Thermodynamics ; Mechanics ; Boundary value problem ; Enthalpy ; Composite material ; Physics Nuclear Materials and Properties ; Advanced ceramic materials synthesis ; Nuclear materials and radiation effects
Authors: Stephan Sleziona | Osamah Kharsah | Lucia Skopinski | Leon Daniel | Jennifer Schmeink | Marika Schleberger
Source: Advanced Electronic Materials (article, 2024-08-12)
Field: Materials Science — Materials Chemistry

Influence of Highly Charged Ion Irradiation on the Electrical and Memory Properties of Black Phosphorus Field‐Effect Transistors Abstract Black phosphorus (bP) is one of the more recently discovered layered materials. Utilizing the hysteresis in the transfer characteristics of bP field‐effect transistors (FETs), several approaches to realize non‐volatile memory devices are successfully demonstrated. This hysteresis is commonly attributed to charge trapping and detrapping in impurities and defects whose nature and location in the device are however unclear. In this work, defects are deliberately introduced into bP FETs by irradiating the devices with highly charged Xe 30 + at a kinetic energy of 180 and 20 keV to manipulate their electrical and memory properties. The results show for the ion with higher energy an increase of conductance and an increase of p‐doping of up to 1.2 · 10 12 cm −2 with increasing fluence, while the charge carrier mobility degrades for the higher ion fluences. Most notably, an increase in the hysteresis' width and of the memory window are observed due to the irradiation. By controlling the kinetic energy of the ions, it can be demonstrated, that the modifications of electronic properties arise from defects in bP and the underlying SiO 2 substrate. However, changes in hysteretic properties are attributed exclusively to irradiation‐induced defects in the substrate, so ion irradiation can significantly improve the properties of bP based memory devices. Materials science ; Irradiation ; Ion ; Substrate (aquarium) ; Optoelectronics ; Hysteresis ; Transistor ; Doping ; Field-effect transistor ; Black phosphorus ; Condensed matter physics ; Voltage ; Electrical engineering ; Chemistry 2D Materials and Applications ; Perovskite Materials and Applications ; MXene and MAX Phase Materials
Authors: Cheng‐Fu Yang | Chih-Hsuan Wang | Pei-Xiu Ke | Teen-­Hang Meen | Kuei‐Kuei Lai
Source: Nanomaterials (article, 2024-05-25)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Development and Fabrication of a Multi-Layer Planar Solar Light Absorber Achieving High Absorptivity and Ultra-Wideband Response from Visible Light to Infrared The objective of this study is to create a planar solar light absorber that exhibits exceptional absorption characteristics spanning from visible light to infrared across an ultra-wide spectral range. The eight layered structures of the absorber, from top to bottom, consisted of Al<sub>2</sub>O<sub>3</sub>, Ti, Al<sub>2</sub>O<sub>3</sub>, Ti, Al<sub>2</sub>O<sub>3</sub>, Ni, Al<sub>2</sub>O<sub>3</sub>, and Al. The COMSOL Multiphysics<sup>®</sup> simulation software (version 6.0) was utilized to construct the absorber model and perform simulation analyses. The first significant finding of this study is that as compared to absorbers featuring seven-layered structures (excluding the top Al<sub>2</sub>O<sub>3</sub> layer) or using TiO<sub>2</sub> or SiO<sub>2</sub> layers as substituted for Al<sub>2</sub>O<sub>3</sub> layer, the presence of the top Al<sub>2</sub>O<sub>3</sub> layer demonstrated superior anti-reflection properties. Another noteworthy finding was that the top Al<sub>2</sub>O<sub>3</sub> layer provided better impedance matching compared to scenarios where it was absent or replaced with TiO<sub>2</sub> or SiO<sub>2</sub> layers, enhancing the absorber's overall efficiency. Consequently, across the ultra-wideband spectrum spanning 350 to 1970 nm, the average absorptivity reached an impressive 96.76%. One significant novelty of this study was the utilization of various top-layer materials to assess the absorption and reflection spectra, along with the optical-impedance-matching properties of the designed absorber. Another notable contribution was the successful implementation of evaporation techniques for depositing and manufacturing this optimized absorber. A further innovation involved the use of transmission electron microscopy to observe the thickness of each deposition layer. Subsequently, the simulated and calculated absorption spectra of solar energy across the AM1.5 spectrum for both the designed and fabricated absorbers were compared, demonstrating a match between the measured and simulated results. Materials science ; Absorption (acoustics) ; Molar absorptivity ; Optoelectronics ; Planar ; Layer (electronics) ; Optics ; Reflection (computer programming) ; Visible spectrum ; Nanotechnology ; Composite material ; Computer science ; Physics Metamaterials and Metasurfaces Applications ; Thermal Radiation and Cooling Technologies ; solar cell performance optimization