jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Muhammad Kashif Mehran | Muhammad Muteeb Butt | Aneela Wakeel
Source: International Journal of Advanced Natural Sciences and Engineering Researches (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

Tempered martensite embrittlement of an alloy steel forging from an automobile vehicle system A thorough root cause analysis was conducted on a prematurely failed wedge component used in defense automobiles. It is made of PCrNi3MoVA, a defense grade alloy steel and is designed to operate in high pressure loading conditions up to 540 MPa. The investigation covered various aspects, including operating conditions, visual examination, chemical composition, bulk hardness, microstructure, and mechanical testing. Overall, an industrial approach was used to determine the root cause of failure. Visual inspection revealed that the fracture surface was flat and there were no signs of beach marks. Mechanical testing revealed that the material had lost its impact strength and had induced brittleness in it. Microstructural analysis revealed tempered martensitic structure directing towards the improper tempering of the material since there was a reduction in toughness. Heat treatment cycle was designed and metallurgical examination was done which showed an improvement in impact toughness of the material. Materials science ; Tempering ; Metallurgy ; Forging ; Embrittlement ; Martensite ; Brittleness ; Toughness ; Microstructure ; Alloy ; High-strength low-alloy steel ; Fracture toughness ; Composite material High-Velocity Impact and Material Behavior ; Microstructure and Mechanical Properties of Steels ; Metal Alloys Wear and Properties
Authors: Weihao Lin | Kong Xiang | Qian Xu | Feng Fang | Wenjun Xia | Wenjun Qi
Source: Microwave and Optical Technology Letters (article, 2023-02-07)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Improving working volume and total scattering cross section using polarization convertor stirrer in a reverberation chamber Abstract In our paper, a stirrer made of a polarization converter for a reverberation chamber (RC) is proposed. A cylindrical polarization converter (PC) stirrer with two unit structures arranged alternatively is placed in RC to take the place of a traditional metallic stirrer. Because of the scattering property of the PC stirrer, it is possible to enlarge the working volume and improve the scattering performance of the stirrer in the RC while maintaining the field uniformity and field anisotropy coefficient to meet the testing standard of the International Electrotechnical Commission 61000‐4‐21. Metallic stirrer and PC stirrer are both placed in the RC simultaneously to make a measurement for guaranteeing the same testing environment. Some parameters of the RC stirred by the PC stirrer or metallic stirrer have been measured and analyzed, such as field uniformity, field anisotropy, coefficient independent sample number and total scattering cross‐section (TSCS), and so on. Testing results verify that the RC stirred by a PC stirrer outperforms the classic RC stirred by a conventional metallic stirrer in terms of some performance, indicating that the proposal has a significant impact on RC testing technology that requires a larger working volume and better TSCS. Electromagnetic reverberation chamber ; Anisotropy ; Scattering ; Polarization (electrochemistry) ; Materials science ; Volume (thermodynamics) ; Acoustics ; Reverberation ; Electronic engineering ; Electrical engineering ; Engineering ; Optics ; Physics ; Chemistry Metamaterials and Metasurfaces Applications ; Electromagnetic Compatibility and Measurements ; Advanced Antenna and Metasurface Technologies
Authors: Mauro Fava | William Lafargue‐Dit‐Hauret | A. Romero | Éric Bousquet
Source: arXiv (Cornell University) (preprint, 2023-11-24)
Field: Materials Science — Materials Chemistry

Ferroelectricity and chirality in the Pb$_5$Ge$_3$O$_{11}$ crystal We study from first-principles calculations the ferroelectric structural phase transition of Pb$_5$Ge$_3$O$_{11}$ crystal. The calculations of phonons and Born effective charges of the paraelectric phase allow us to identify a polar instability that is unstable in both transverse-optic and longitudinal-optic versions, giving rise to an entire branch of instability along a propagation vector parallel to the mode polarization (the hexagonal axe). This is the hint of hyperferroelectricity and the stable head-to-head and tail-to-tail domain, as recently reported from both experiments and theory. Then, our analysis of the ferroelectric phase shows that the polarization of Pb$_5$Ge$_3$O$_{11}$ is uniaxial along the hexagonal axes and with small in-plane components due to a piezoelectric effect. The symmetry-adapted mode analysis shows that the total ferroelectric ground state distortion comes mainly from polar distortions of the unstable polar phonon mode but also from an invariant, cooperative mode that amplifies the polar deformation. We also build a phenomenological model that highlights how the coupling between these modes is at play and helps us understand how to reproduce the second-order phase transition. At last, we also quantify the structural chirality through the continuous symmetry measure method and trace its origin to the polar unstable mode itself. By extending our approach to the phonon states we further show that the chirality is poorly affected by the relaxation but could also be enhanced by activating high frequency modes with polar symmetry. Finally we study the phonon angular momentum (AM) distribution in both phases and identify trends in the AM behaviour across the Brillouin zone. Ferroelectricity ; Chirality (physics) ; Materials science ; Crystallography ; Crystal (programming language) ; Nanotechnology ; Optoelectronics ; Chemistry ; Physics ; Dielectric ; Computer science ; Quantum mechanics ; Chiral symmetry Solid-state spectroscopy and crystallography ; Acoustic Wave Resonator Technologies ; Glass properties and applications
Authors: Carlo Silvestri | Xiaoqiong Qi | Thomas Taimre | Aleksandar D. Rakić
Source: arXiv (Cornell University) (preprint, 2023-05-08)
Field: Chemistry — Spectroscopy

Frequency combs induced by optical feedback and harmonic order tunability in quantum cascade lasers This study investigates the interaction between frequency combs and optical feedback effects in Quantum Cascade Lasers (QCLs). The theoretical analysis reveals new phenomena arising from the interplay between comb generation and feedback. By considering the bias current corresponding to free-running single mode emission, the introduction of optical feedback can trigger the generation of frequency combs, including both fundamental and harmonic combs. This presents opportunities to extend the comb region and generate harmonic frequency combs with different orders through optimization of external cavity parameters such as losses and length. Furthermore, the study demonstrates that optical feedback can selectively tune the harmonic order of a pre-existing free-running comb by adjusting the external cavity length, particularly for feedback ratios around 1%, which are readily achievable in experimental setups. Under strong feedback conditions (Acket parameter C&gt;4.6), mixed states emerge, displaying the features of both laser and external cavity dynamics. While the study is predominantly centered on Terahertz QCLs, we have also confirmed that the described phenomena occur when utilizing mid-infrared QCL parameters. This work establishes a connection between comb technology and the utilization of optical feedback, providing new avenues for exploration and advancement in the field. In fact, the novel reported phenomena open a pathway towards new methodologies across various domains, such as design of tunable comb sources, hyperspectral imaging, multimode coherent sensing, and multi-channel communication. Cascade ; Frequency comb ; Laser ; Multi-mode optical fiber ; Physics ; Terahertz radiation ; Harmonic ; Quantum cascade laser ; Quantum ; Optics ; Optoelectronics ; Computer science ; Optical fiber ; Quantum mechanics ; Engineering Spectroscopy and Laser Applications ; Laser Design and Applications ; Advanced Fiber Laser Technologies
Authors: Mahfujur Rahaman | Gwangwoo Kim | Kyung Yeol | Seunguk Song | Hyeon Suk Shin | Deep Jariwala
Source: Research Square (preprint, 2023-06-16)
Field: Materials Science — Materials Chemistry

Tailoring Exciton Dynamics in TMDC Heterobilayers in the Quantum Plasmonic Regime Abstract Control of excitons in transition metal dichalcogenides (TMDCs) and their heterostructures is fundamentally interesting for tailoring light-matter interactions and exploring their potential applications in high-efficiency optoelectronic and nonlinear photonic devices. While both intra- and interlayer excitons in TMDCs have been heavily studied, their behavior in the quantum tunneling regime, in which the TMDC or its heterostructure is optically excited and concurrently serves as a tunnel junction barrier, remains unexplored. Here, using the degree of freedom of a metallic probe in an atomic force microscope, we investigated both intralayer and interlayer excitons dynamics in TMDC heterobilayers via locally controlled junction current in a finely tuned sub-nanometer tip-sample cavity. Our tip-enhanced photoluminescence measurements reveal a significantly different exciton-quantum plasmon coupling for intralayer and interlayer excitons due to different orientation of the dipoles of the respective e-h pairs. Using a steady-state rate equation fit, we extracted field gradients, radiative and nonradiative relaxation rates for excitons in the quantum tunneling regime with and without junction current. Our results show that tip-induced radiative (nonradiative) relaxation of intralayer (interlayer) excitons becomes dominant in the quantum tunneling regime due to the Purcell effect. These findings have important implications for near-field probing of excitonic materials in the strong-coupling regime. Plasmon ; Exciton ; Dynamics (music) ; Quantum ; Nanotechnology ; Materials science ; Optoelectronics ; Condensed matter physics ; Physics ; Quantum mechanics 2D Materials and Applications ; Quantum Dots Synthesis And Properties ; Perovskite Materials and Applications
Authors: Urban Senica | Sebastian Gloor | Paolo Micheletti | David Stark | Mattias Beck | Jérôme Faist | Giacomo Scalari
Source: arXiv (Cornell University) (preprint, 2023-06-17)
Field: Chemistry — Spectroscopy

Broadband surface-emitting THz laser frequency combs with inverse-designed integrated reflectors THz quantum cascade lasers (QCLs) based on double metal waveguides feature broadband and high-temperature devices for use in spectroscopy and sensing. However, their extreme field confinement produces poor output coupling efficiencies and divergent far-fields. Here, we present a planarized THz QCL with an inverse-designed end facet reflector coupled to a surface-emitting patch array antenna. All the components have been optimized for octave-spanning spectral bandwidths between 2-4 THz and monolithically integrated on the same photonic chip. We demonstrate this experimentally on broadband THz QCL frequency combs, with measured devices showing a seven-fold improvement in slope efficiency compared to devices with a cleaved facet. They feature peak powers of up to 13.5 mW with surface emission into a narrow beam with a divergence of (17.0°x 18.5°), while broadband fundamental and harmonic comb states spanning up to 800 GHz are observed. Broadband ; Terahertz radiation ; Optics ; Optoelectronics ; Materials science ; Laser ; Reflector (photography) ; Quantum cascade laser ; Physics Spectroscopy and Laser Applications ; Photonic and Optical Devices ; Advanced Fiber Laser Technologies
Authors: Anna Špačková | Václav Bazgier | Tomáš Raček | David Sehnal | Radka Svobodová Vařeková | Karel Berka
Source:  (preprint, 2023-10-02)
Field: Chemistry — Spectroscopy

Analysis and Visualization of Protein Channels, Tunnels and Pores with MOLEonline &amp;amp; ChannelsDB 2.0 MOLEonline (https://mole.upol.cz) is an interactive web-based tool with enhanced capabilities for detecting and characterising channels, tunnels and pores within proteins. It facilitates two distinct calculation modes for channel analysis and transmembrane pores, accommodating a wide range of structural data formats such as mmCIF or older PDF. This application gives researchers rich analytical insights into channel detection, structural characterisation, and physicochemical properties. ChannelsDB 2.0 (https://channelsdb2.biodata.ceitec.cz/) is a comprehensive database that offers information on the location, geometry, and physicochemical characteristics of tunnels and pores within macromolecular structures deposited in Protein Data Bank and AlphaFill databases. These tunnels are sourced from manual deposition from literature and automatic detection using software tools MOLE and CAVER. In both cases, MOLEonline and ChannelsDB, visualisation is powered by LiteMol Viewer, ensuring a user-friendly workspace. This chapter provides an overview of user applications and usage. Visualization ; Workspace ; Software ; Computer science ; Channel (broadcasting) ; Range (aeronautics) ; Chemistry ; Data mining ; Materials science ; Operating system ; Artificial intelligence Advanced Proteomics Techniques and Applications ; Mass Spectrometry Techniques and Applications
Authors: G. Savorianakis | Stéphanos Konstantinidis | M. Voué | Björn Maes | Nicolas Martin
Source: ORBi UMONS (article, 2023-11-10)
Field: Materials Science — Polymers and Plastics

Enhancing the Electrical and Optical Properties of Thermochromic VO2: The Impact of Nanostructuring and Gold Nanoparticles peer reviewed Thermochromism ; Colloidal gold ; Nanoparticle ; Nanostructure ; Nanomaterials Transition Metal Oxide Nanomaterials ; Catalysis and Oxidation Reactions ; Gas Sensing Nanomaterials and Sensors
Authors: Camilla Sammartino | Yair Shokef | Bat‐El Pinchasik
Source: arXiv (Cornell University) (preprint, 2023-07-04)
Field: Materials Science — Surfaces, Coatings and Films

Percolation in Networks of Liquid Diodes Liquid diodes are surface structures that facilitate the flow of liquids in a specific direction. When these structures are within the capillary regime, they promote liquid transport without the need for external forces. In nature, they are used to increase water collection and uptake, reproduction, and feeding. While nature offers various one-dimensional channels for unidirectional transport, networks with directional properties are exceptional and typically limited to millimeters or a few centimeters. In this study, we simulate, design and 3D print liquid diode networks consisting of hundreds of unit cells. We provide structural and wettability guidelines for directional transport of liquids through these networks, and introduce percolation theory in order to identify the threshold between a connected network, which allows fluid to reach specific points, and a disconnected network. By constructing well-defined networks that combine uni- and bi-directional pathways, we experimentally demonstrate the applicability of models describing isotropically directed percolation. By varying the surface structure and the solid-liquid interfacial tension, we precisely control the portion of liquid diodes and bidirectional connections in the network and follow the flow evolution. We are, therefore, able to accurately predict the network permeability and the liquid's final state. These guidelines are highly promising for the development of structures for spontaneous, yet predictable, directional liquid transport. Percolation (cognitive psychology) ; Capillary action ; Wetting ; Materials science ; Surface tension ; Percolation theory ; Diode ; Flow (mathematics) ; Mechanics ; Computer science ; Topology (electrical circuits) ; Physics ; Optoelectronics ; Engineering ; Electrical engineering Surface Modification and Superhydrophobicity ; Modular Robots and Swarm Intelligence ; Music Technology and Sound Studies
Authors: Sven Nordebo
Source: arXiv (Cornell University) (preprint, 2023-03-21)
Field: Chemistry — Spectroscopy

A modified projection approach to line mixing This paper presents a simple approach to combine the high-resolution narrowband features of some desired isolated line models together with the far wing behavior of the projection based strong collision (SC) method to line mixing which was introduced by Bulanin, Dokuchaev, Tonkov and Filippov. The method can be viewed in terms of a small diagonal perturbation of the SC relaxation matrix providing the required narrowband accuracy close to the line centers at the same time as the SC line coupling transfer rates are retained and can be optimally scaled to thermalize the radiator after impact. The method can conveniently be placed in the framework of the Boltzmann-Liouville transport equation where a rigorous diagonalization of the line mixing problem requires that molecular phase and velocity changes are assumed to be uncorrelated. A detailed analysis for the general Doppler case is given based on the first order Rosenkranz approximation, and which also provides the possibility to incorporate quadratically speed dependent parameters. Exact solutions for pure pressure broadening and explicit Rosenkranz approximations are given in the case with velocity independent parameters (line frequency, strength, width and shift) which can readily be retrieved from databases such as HITRAN for a large number of species. Numerical examples including comparisons to published measured data are provided in two specific cases concerning the absorption of carbon dioxide in its infrared band of asymmetric stretching, as well as of atmospheric water vapor and oxygen in relevant millimeter bands. HITRAN ; Splitter plate ; Narrowband ; Mixing (physics) ; Line (geometry) ; Computational physics ; Boltzmann equation ; Perturbation (astronomy) ; Statistical physics ; Physics ; Spectral line ; Mechanics ; Mathematics ; Optics ; Quantum mechanics ; Geometry Spectroscopy and Laser Applications ; Atmospheric Ozone and Climate ; Atmospheric chemistry and aerosols
Authors: Akshay Kumar | Suvasis Swain | J. Upadhyay | Yogesh Upalekar | Rajesh Arya | Vaibhav S. Prabhudesai
Source: arXiv (Cornell University) (preprint, 2023-01-24)
Field: Chemistry — Spectroscopy

Predissociation dynamics of negative ion resonances of H$_2$ near 12 eV and 14.5 eV using velocity slice imaging technique Dissociative electron attachment (DEA) is an important tool for investigating negative ion resonances. We have studied the negative ion resonances of H2 at 10 eV and 14 eV using the improved velocity slice imaging technique. We obtained modulations in the kinetic energy spectrum of H$^-$ ions obtained at 12 eV and 14.5 eV electron energy, consistent with the earlier reported vibrational state contributions from the higher lying bound resonances. We show that structures obtained at 12 eV are due to predissociation of the $C^2Σ_g^+$ resonance consistent with the current understanding. However, based on our angular distribution measurements, we propose that the structures obtained at 14.4 eV are due to predissociation of bound resonance of $^2Σ_g^+$ symmetry as against $δ_g$ that was proposed earlier. We also report that the bound $^2Σ_g^+$ resonance contributes to the observed inversion symmetry breaking near 14 eV. Ion ; Dynamics (music) ; Atomic physics ; Physics ; Quantum mechanics ; Acoustics Spectroscopy and Laser Applications ; Atomic and Molecular Physics ; Atomic and Subatomic Physics Research
Authors: Cristiana Sessa | Patricia LoRusso | Anthony W. Tolcher | Françoise Farace | Nathalie Lassau | Angelo Delmonte | Antonio Braghetti | Rastislav Bahleda | Patrick Cohen | Marie Hospitel | Christine Veyrat‐Follet | Jean‐Charles Soria
Source:  (preprint, 2023-03-31)
Field: Chemistry — Organic Chemistry

Supplementary Text from Phase I Safety, Pharmacokinetic and Pharmacodynamic Evaluation of the Vascular Disrupting Agent Ombrabulin (AVE8062) in Patients with Advanced Solid Tumors &lt;p&gt;Supplementary Text - PDF file 76K, DCE methodology and results&lt;/p&gt; Pharmacodynamics ; Pharmacokinetics ; Medicine ; Phase (matter) ; Pharmacology ; Chemistry Click Chemistry and Applications ; Metal complexes synthesis and properties ; Cancer Treatment and Pharmacology
Authors: Cristiana Sessa | Patricia LoRusso | Anthony W. Tolcher | Françoise Farace | Nathalie Lassau | Angelo Delmonte | Antonio Braghetti | Rastislav Bahleda | Patrick Cohen | Marie Hospitel | Christine Veyrat‐Follet | Jean‐Charles Soria
Source:  (preprint, 2023-03-31)
Field: Chemistry — Organic Chemistry

Supplementary Text from Phase I Safety, Pharmacokinetic and Pharmacodynamic Evaluation of the Vascular Disrupting Agent Ombrabulin (AVE8062) in Patients with Advanced Solid Tumors &lt;p&gt;Supplementary Text - PDF file 76K, DCE methodology and results&lt;/p&gt; Pharmacodynamics ; Pharmacokinetics ; Phase (matter) ; Medicine ; Pharmacology ; Internal medicine ; Computer science ; Chemistry Click Chemistry and Applications ; Metal complexes synthesis and properties ; Cancer Treatment and Pharmacology
Authors: V. N. Glazkov | Yu. V. Krasnikova | I. K. Rodygina | H.‐A. Krug von Nidda | Takatsugu Masuda
Source: arXiv (Cornell University) (preprint, 2023-04-03)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Magnetic resonance in the quasi-2D square lattice easy-plane antiferromagnet Ba$_2$MnGe$_2$O$_7$ We report results of a multi-frequency (0.8-60 GHz) electron spin resonance study of the spin dynamics in the quasi-2D square lattice antiferromagnet Ba$_2$MnGe$_2$O$_7$ both in antiferromagnetically ordered and paramagnetic phases. We directly observe two zero-field gaps in the excitation spectrum of the ordered phase, the larger one being due to easy-plane anisotropy, and the smaller one indicates the presence of fourth-order in-plane anisotropy probably related to the multiferroic properties of this compound. We observe effects of hyperfine interaction on the electron spin resonance spectra in the antiferromagnetically ordered state, which turns out to be comparable with in-plane anisotropy. The hyperfine field strength is found from the observed low-temperature electron spin resonance data. The spin dynamics of the paramagnetic phase is characterized by strong broadening of the ESR absorption line, which can be ascribed to the vortex dynamics of a 2D magnet. Antiferromagnetism ; Condensed matter physics ; Hyperfine structure ; Electron paramagnetic resonance ; Paramagnetism ; Anisotropy ; Resonance (particle physics) ; Square lattice ; Materials science ; Physics ; Nuclear magnetic resonance ; Atomic physics ; Ising model Multiferroics and related materials ; Physics of Superconductivity and Magnetism ; Advanced Condensed Matter Physics