jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Frédéric Paquin-Lefebvre | David Holcman
Source: arXiv (Cornell University) (preprint, 2023-11-14)
Field: Chemistry — Electrochemistry

Modeling ionic flow between small targets: insights from diffusion and electro-diffusion theory The flow of ions through permeable channels causes voltage drop in physiological nanodomains such as synapses, dendrites and dendritic spines, and other protrusions. How the voltage changes around channels in these nanodomains has remained poorly studied. We focus this book chapter on summarizing recent efforts in computing the steady-state current, voltage and ionic concentration distributions based on the Poisson-Nernst-Planck equations as a model of electro-diffusion. We first consider the spatial distribution of an uncharged particle density and derive asymptotic formulas for the concentration difference by solving the Laplace's equation with mixed boundary conditions. We study a constant particles injection rate modeled by a Neumann flux condition at a channel represented by a small boundary target, while the injected particles can exit at one or several narrow patches. We then discuss the case of two species (positive and negative charges) and take into account motions due to both concentration and electrochemical gradients. The voltage resulting from charge interactions is calculated by solving the Poisson's equation. We show how deep an influx diffusion propagates inside a nanodomain, for populations of both uncharged and charged particles. We estimate the concentration and voltage changes in relations with geometrical parameters and quantify the impact of membrane curvature. Diffusion ; Laplace transform ; Mechanics ; Boundary value problem ; Poisson's equation ; Ionic bonding ; Chemistry ; Laplace's equation ; Ion ; Diffusion equation ; Steady state (chemistry) ; Voltage ; Physics ; Chemical physics ; Thermodynamics ; Mathematical analysis ; Mathematics ; Quantum mechanics ; Physical chemistry Electrochemical Analysis and Applications ; Nanopore and Nanochannel Transport Studies ; Lipid Membrane Structure and Behavior
Authors: Roselle Ngaloy | Bing Zhao | Soheil Ershadrad | Rahul Gupta | Masoumeh Davoudiniya | Lakhan Bainsla | Lars Sjöström | Md. Anamul Hoque | Alexei Kalaboukhov | Peter Svedlindh | Biplab Sanyal | Saroj P. Dash
Source: arXiv (Cornell University) (preprint, 2023-10-30)
Field: Materials Science — Materials Chemistry

Strong in-plane magnetic anisotropy (Co0.15Fe0.85)5GeTe2/graphene van der Waals heterostructure spin-valve at room temperature Van der Waals (vdW) magnets are promising owing to their tunable magnetic properties with doping or alloy composition, where the strength of magnetic interactions, their symmetry, and magnetic anisotropy can be tuned according to the desired application. However, most of the vdW magnet based spintronic devices are so far limited to cryogenic temperatures with magnetic anisotropies favouring out-of-plane or canted orientation of the magnetization. Here, we report room-temperature lateral spin-valve devices with strong in-plane magnetic anisotropy of the vdW ferromagnet (Co0.15Fe0.85)5GeTe2 (CFGT) in heterostructures with graphene. Magnetization measurements reveal above room-temperature ferromagnetism in CFGT with a strong in-plane magnetic anisotropy. Density functional theory calculations show that the magnitude of the anisotropy depends on the Co concentration and is caused by the substitution of Co in the outermost Fe layer. Heterostructures consisting of CFGT nanolayers and graphene were used to experimentally realize basic building blocks for spin valve devices such as efficient spin injection and detection. The spin transport and Hanle spin precession measurements prove a strong in-plane and negative spin polarization at the interface with graphene, which is supported by the calculated spin-polarized density of states of CFGT. The in-plane magnetization of CFGT at room temperature proves its usefulness in graphene lateral spin-valve devices, thus opening further opportunities for spintronic technologies. Condensed matter physics ; Spintronics ; Materials science ; Magnetization ; Magnetic anisotropy ; Spin valve ; Spin polarization ; Ferromagnetism ; Magnetocrystalline anisotropy ; Graphene ; van der Waals force ; Anisotropy ; Curie temperature ; Spin (aerodynamics) ; Magnetic field ; Physics ; Nanotechnology ; Optics 2D Materials and Applications ; Magnetic properties of thin films ; Graphene research and applications
Authors: Bérénice Grec | Srboljub Simić
Source: arXiv (Cornell University) (preprint, 2023-05-15)
Field: Materials Science — Materials Chemistry

Higher-order Maxwell-Stefan model of diffusion The paper studies a higher-order diffusion model of Maxwell-Stefan kind. The model is based upon higher-order moment equations of kinetic theory of mixtures, which include viscous dissipation in the model. Governing equations are analyzed in a scaled form, which introduces the proper orders of magnitude of each term. In the socalled diffusive scaling, the Mach and Knudsen numbers are assumed to be of the same small order of magnitude. In the asymptotic limit when the small parameter vanishes, the model exhibits a coupling between the species' partial pressure gradients, which generalizes the classical model. Scaled equations also lead to a higher-order model of diffusion with correction terms in the small parameter. In that case, the viscous tensor is determined by genuine balance laws. Knudsen number ; Mach number ; Diffusion ; Scaling ; Order (exchange) ; Physics ; Moment (physics) ; Mathematics ; Classical mechanics ; Mathematical physics ; Mechanics ; Thermodynamics ; Geometry Material Dynamics and Properties ; Advanced Thermodynamics and Statistical Mechanics ; nanoparticles nucleation surface interactions
Authors: J. J. Erik Maris | Luke A. Parker | Katarína Stančiaková | Nikolaos Nikolopoulos | Koen M. H. Berendsen | Alfons van Blaaderen | Florian Meirer | Freddy T. Rabouw | Bert M. Weckhuysen
Source: Chemistry - A European Journal (article, 2023-12-13)
Field: Chemistry — Physical and Theoretical Chemistry

Molecular Accessibility and Diffusion of Resorufin in Zeolite Crystals Invited for the cover of this issue is the group of Professor Bert Weckhuysen at Utrecht University. The image depicts the change in fluorescence color of a resorufin dye molecule when it is protonated and confined inside the micropores of zeolite-β. Read the full text of the article at 10.1002/chem.202302553. Protonation ; Zeolite ; Cover (algebra) ; Molecule ; Fluorescence ; Diffusion ; Chemistry ; Photochemistry ; Materials science ; Crystallography ; Physics ; Organic chemistry ; Optics ; Engineering Photochemistry and Electron Transfer Studies ; Porphyrin and Phthalocyanine Chemistry ; Metal complexes synthesis and properties
Authors: Georgy Alymov | Dmitry Svintsov
Source: arXiv (Cornell University) (preprint, 2023-10-11)
Field: Materials Science — Materials Chemistry

Ultimate sharpness of the tunneling resonance in vertical heterostructures Heterostructures comprised of two two-dimensional electron systems (2DES) separated by a dielectric exhibit resonant tunneling when the band structures of both systems are aligned. It is commonly assumed that the height and width of the resonant peak in the tunneling current is determined by electron scattering and rotational misalignment of crystal structures of the 2DES. We identify two fundamental factors limiting the maximum height and steepness of the resonance: coupling to contacts and tunnel splitting of energy levels. The upper limit of the tunneling current is the number of electrons available for tunneling times half the tunnel coupling between the 2DES. As a result of a tradeoff between the contact-induced level broadening and contact resistance, the maximum current is only achievable when the coupling to contacts equals the tunnel level splitting. According to our model calculations, the limiting behavior can be observed in double-gated graphene/few-layer hexagonal boron nitride/graphene heterostructures. Quantum tunnelling ; Heterojunction ; Condensed matter physics ; Electron ; Resonance (particle physics) ; Coupling (piping) ; Graphene ; Scattering ; Crystal (programming language) ; Materials science ; Physics ; Atomic physics ; Optics ; Nanotechnology ; Quantum mechanics Graphene research and applications ; Quantum and electron transport phenomena ; Surface and Thin Film Phenomena
Authors: Sandy Poncet | Cédric Mehl | Karine Truffin | Olivier Colin
Source: SPIRE - Sciences Po Institutional REpository (article, 2023-04-26)
Field: Materials Science — Polymers and Plastics

Modified diffusion model adapted to non-unity Lewis number mixtures for low flame stretch using the thickened flame model International audience Lewis number ; Diffusion ; Materials science ; Diffusion flame ; Mechanics ; Acoustics ; Computer science ; Composite material ; Chemistry ; Combustion ; Thermodynamics ; Physics ; Physical chemistry Flame retardant materials and properties ; Material Science and Thermodynamics ; Catalytic Processes in Materials Science
Authors: Zhaoyi Yan | Zhan Hou | Kan‐Hao Xue | Tian Lu | Ruiting Zhao | Junying Xue | Fan Wu | Minghao Shao | Jianlan Yan | Anzhi Yan | Zhenze Wang | Penghui Shen | Mingyue Zhao | Xiangshui Miao | Zhaoyang Lin | Houfang Liu | He Tian | Yi Yang | Tian‐Ling Ren
Source: arXiv (Cornell University) (preprint, 2023-03-20)
Field: Materials Science — Materials Chemistry

Landauer-QFLPS model for mixed Schottky-Ohmic contact two-dimensional transistors Two-dimensional material-based field effect transistors (2DM-FETs) are playing a revolutionary role in electronic devices. However, after years of development, no device model can match the Pao-Sah model for standard silicon-based transistors in terms of physical accuracy and computational efficiency to support large-scale integrated circuit design. One remaining critical obstacle is the contacts of 2DM-FETs. In order to self-consistently include the contact effect in the current model, it is necessary to perform self-consistent calculations, which is a fatal flaw for applications that prioritize efficiency. Here, we report that the Landauer-QFLPS model effectively overcomes the above contradiction, where QFLPS means quasi-Fermi-level phase space theory. By connecting the physical pictures of the contact and the intrinsic channel part, we have successfully derived a drain-source current formula including the contact effect. To verify the model, we prepared transistors based on two typical 2DMs, black phosphorus (BP) and molybdenum disulfide (MoS2), the former having ambipolar transport and the latter showing electron-dominant unipolar transport. The proposed new formula could describe both 2DM-FETs with Schottky or Ohmic contacts. Moreover, compared with traditional methods, the proposed model has the advantages of accuracy and efficiency, especially in describing non-monotonic drain conductance characteristics, because the contact effect is self-consistently and compactly packaged as an exponential term. More importantly, we also examined the model at the circuit level. Here, we fabricated a three-bit threshold inverter quantizer circuit based on ambipolar-BP process and experimentally demonstrated that the model can accurately predict the circuit performance. This industry-benign 2DM-FET model is supposed to be very useful for the development of 2DM-FET-based integrated circuits. Ohmic contact ; Ambipolar diffusion ; Transistor ; Schottky barrier ; Schottky diode ; Materials science ; Optoelectronics ; Electronic engineering ; Computer science ; Electrical engineering ; Computational physics ; Physics ; Voltage ; Nanotechnology ; Electron ; Diode ; Engineering ; Quantum mechanics 2D Materials and Applications ; Ferroelectric and Negative Capacitance Devices ; Graphene research and applications
Authors: Feng Wang | Emma C. Regan | Zheyu Lu | Danqing Wang | Yang Zhang | Trithep Devakul | Jacob Nie | Zuocheng Zhang | Wenyu Zhao | Kenji Watanabe | Takashi Taniguchi | Sefaattin Tongay | Alex Zettl | Liang Fu
Source: Research Square (preprint, 2023-09-15)
Field: Materials Science — Materials Chemistry

Spin transport of a doped Mott insulator in moiré heterostructures Condensed matter physics ; Mott insulator ; Superlattice ; Spin (aerodynamics) ; Spin diffusion ; Heterojunction ; Spins ; Doping ; Physics ; Spin Hall effect ; Materials science ; Spin polarization ; Electron ; Quantum mechanics ; Ferromagnetism 2D Materials and Applications ; Quantum and electron transport phenomena ; Electronic and Structural Properties of Oxides
Authors: U. A. Zaitsau | V. S. Melnikova | D. A. Podryabinkin | A. L. Danilyuk
Source: HERALD OF POLOTSK STATE UNIVERSITY Series С FUNDAMENTAL SCIENCES (article, 2023-10-31)
Field: Materials Science — Materials Chemistry

ELECTROPHYSICAL PARAMETERS INTERRELATION MODEL FOR CAD SYSTEMS A model is presented and regularities are established for the relationship between the electrophysical parameters&#x0D; of a transistor structure and a two-dimensional channel, based on the self-consistency of the electrochemical&#x0D; potential and the concentration of charge carriers of a two-dimensional channel in a field-effect transistor&#x0D; structure. Such self-consistency is ensured by combining the Fermi – Dirac statistics with the condition of electrical&#x0D; neutrality of the transistor structure. The effect on the electrophysical parameters of a transistor structure&#x0D; with a two-dimensional semiconductor channel is considered for the band gap of the channel material, the capacitance&#x0D; of the gate dielectric, and the capacitance of interface states. The developed model of the relationship between&#x0D; the electrophysical parameters of a transistor structure with a two-dimensional channel can be used in computeraided&#x0D; design systems for the element base of micro- and nanoelectronics. Transistor ; Capacitance ; Materials science ; Field-effect transistor ; Channel (broadcasting) ; Consistency (knowledge bases) ; Semiconductor ; Electronic engineering ; Optoelectronics ; Physics ; Electrical engineering ; Computer science ; Engineering ; Electrode ; Quantum mechanics ; Voltage Graphene research and applications ; 2D Materials and Applications ; Semiconductor materials and interfaces
Authors: Masaki Ota | Masato Urabe | Koichiro Nomura | Yuya Hiraga | Masaru Watanabe | Hiroshi Inomata
Source: Nippon Shokuhin Kagaku Kogaku Kaishi (article, 2023-07-20)
Field: Materials Science — Materials Chemistry

Dynamic semi-batch supercritical fluid extraction model based on fundamentally thermodynamic equilibrium properties 本研究では, 熱力学物性に基づく新しい抽出モデルを開発することができた. このモデルは, Henry型の分配係数のほか, Langmuir式などの吸着等温式を許容することができるモデルであり, 理論予測が難しい物質移動係数や拡散係数などの速度論パラメータを介さない点で利便性が高いものである. また, ここで構築した数理モデルは, 超臨界CO2純溶媒に限らず, 均一相系の溶媒であれば液体抽出などにも応用できる. さらに, 食品などへの展開を想定すると, 複数溶質を含む場合のモデル上での取り扱いも必要になるが, 溶質間の相互作用が無視できる状態であれば, 溶質ごとに個別に計算することで多成分系にも展開できるものである. 今後, 熱力学基礎物性に基づく抽出挙動の完全予測が期待される. Chemistry Crystallization and Solubility Studies ; Analytical Chemistry and Chromatography ; Phase Equilibria and Thermodynamics
Authors: Jared C. Stimac | Chad Serrao | Jeremy K. Mason
Source: arXiv (Cornell University) (preprint, 2023-01-11)
Field: Materials Science — Materials Chemistry

Dependence of simulated radiation damage on crystal structure and atomic misfit in metals This study investigates radiation damage in three metals in the low temperature and high radiant flux regime using molecular dynamics and a Frenkel pair accumulation method to simulate up to $2.0$ displacements per atom. The metals considered include Fe, equiatomic CrCoNi, and a fictitious metal with identical bulk properties to the CrCoNi composed of a single atom type referred to as an A-atom. CrCoNi is found to sustain higher concentrations of dislocations than either the Fe or A-atom systems and more stacking faults than the A-atom system. The results suggest that the concentration of vacancies and interstitials are substantially higher for the CrCoNi than the A-atom system, perhaps reflecting that the recombination radius is smaller in CrCoNi due to the roughened potential energy landscape. A model that partitions the major contributions from defects to the stored energy is described, and serves to highlight a general need for higher fidelity approaches to point defect identification. Atom (system on chip) ; Materials science ; RADIUS ; Embedded atom model ; Crystallographic defect ; Radiation damage ; Stacking ; Molecular dynamics ; Atomic radius ; Metal ; Dislocation ; Frenkel defect ; Radiation ; Crystal (programming language) ; Atomic physics ; Perfect crystal ; Molecular physics ; Condensed matter physics ; Physics ; Chemistry ; Vacancy defect ; Computational chemistry ; Optics ; Metallurgy Nuclear Materials and Properties ; Intermetallics and Advanced Alloy Properties ; Fusion materials and technologies
Authors: Jinrong Liu | Liujun Xu | Gaole Dai | Gang Wang
Source: arXiv (Cornell University) (preprint, 2023-10-19)
Field: Materials Science — Materials Chemistry

Analysis of Geometric Phases in Particle Diffusion Systems: Insights from Non-Hermitian Heat Transfer Geometric phases in particle diffusion systems, an intriguing aspect enlightened from thermal systems, offer a different understanding beyond traditional Brownian motion and Fick's laws. This concept introduces a phase factor with significant implications for particle behavior, central to which is the non-Hermitian nature of the Hamiltonian in the diffusion system. A unique structure composed of two rings moving in opposite directions and a stationary intermediate layer plays multifunctional roles in controlling particle diffusion. For the real-world application, a bilayer particle-diffusion cloak is demonstrated, showcasing the extensive control and adaptability achievable through mastering geometric phases. This system has potential applications in industries like healthcare and environmental management, thus expanding the understanding of the geometric phase and offering insights for the design of particle-diffusion metamaterials. Brownian motion ; Diffusion ; Statistical physics ; Particle (ecology) ; Particle system ; Hamiltonian (control theory) ; Hermitian matrix ; Classical mechanics ; Physics ; Computer science ; Mathematics ; Thermodynamics ; Mathematical optimization ; Quantum mechanics Pickering emulsions and particle stabilization ; Heat and Mass Transfer in Porous Media ; Particle Dynamics in Fluid Flows
Authors: Oussama Benhacene | Rachid Boucetta
Source: International Conference on Applied Engineering and Natural Sciences (article, 2023-07-20)
Field: Chemistry — Analytical Chemistry

Numerical Study: Comparison of Paraffin Deposition In The Laminar And Turbulent Regime The problem of paraffin deposits in oil wells and pipelines monopolizes substantial human and economic resources. Its prediction is, therefore, essential to optimize its management. The formation of the deposit arises from a delicate interplay of hydrodynamic, thermal, and thermodynamic factors, alongside paraffin diffusion and the rheology of the crude oil. This research has resulted in a better understanding and calculation of the rates at which wax is removed. Furthermore, the study has suggested the presence of two distinct flowing regions in turbulent and laminar flow, which results in the formation of thin solid sediments attached to the pipe wall.By conducting this numerical study using FORTRAN, we can gain insights and optimize the design and operation of pipelines and maintain efficient production. The study also involved a rough comparison between the results obtained from two different types of flow. This approach, which considers the viscoelastic behavior of paraffinic crude, allows for a more accurate prediction of deposit formation. With this enhanced understanding, we can develop improved strategies for managing paraffin build-up, minimizing resource allocation and costs associated with its removal. Ultimately, optimizing the design and operation of pipelines will contribute to the maintenance of efficient production in the oil industry. Laminar flow ; Pipeline transport ; Turbulence ; Petroleum engineering ; Rheology ; Deposition (geology) ; Flow (mathematics) ; Materials science ; Computational fluid dynamics ; Viscoelasticity ; Mechanics ; Computer science ; Process engineering ; Environmental science ; Geology ; Engineering ; Composite material ; Environmental engineering ; Physics Petroleum Processing and Analysis ; Enhanced Oil Recovery Techniques ; Reservoir Engineering and Simulation Methods
Authors: Eduarda Bertoletti Duarte | Luciana Cristina Soto Herek Rezende
Source: Periódico Eletrônico Fórum Ambiental da Alta Paulista (article, 2023-03-08)
Field: Chemistry — Analytical Chemistry

Removal of Methylene Blue from a residue as a low-cost biosorbent: peanut hull (Arachis hypogaea) The textile industry is still very relevant for people’s everyday life and their production of goods, however, throughout the production chains, there are impacts on the environment, such as the elimination of effluents with the presence of dyes used in the production processes. These substances can cause environmental contamination if untreated, and the proper treatment for them is adsorption. This technique, although efficient, has a high cost, which favors the use of natural adsorbents, especially the usage of abundant residues in the environment. Therefore, this paper aims at using an agro-industrial residue, peanut hulls, produced on a large scale, as an adsorbent in the treatment of wastewater using the dye methylene blue. The Bel® SPECTRO S-2000 UV-visible spectrophotometer at a wavelength of 664 nm was used to analyze the absorbance of the dye concentrations. These data were used in the construction of the calibration curve, where the values found were calculated to obtain the adsorption capacity, which allowed us to identify the efficiency of the biosorbent. The results obtained were compared with the literature, and although the experiment had different conditions, the peanut hulls presented an adsorption capacity of 4.26925 mg/g, which represents an efficiency. Nevertheless, further studies are needed to carry out other analyses to evaluate the conditions that allow an increase in the adsorption capacity. Adsorption ; Absorbance ; Effluent ; Methylene blue ; Wastewater ; Pulp and paper industry ; Arachis hypogaea ; Chemistry ; Contamination ; Environmental science ; Environmental engineering ; Chromatography ; Organic chemistry ; Horticulture ; Biology ; Engineering Dye analysis and toxicity ; Water Quality Monitoring and Analysis