jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Mohammad Alidoust | David Kleiven | Jaakko Akola
Source: Physical Review Materials (article, 2020-04-20)
Field: Materials Science — Biomaterials

Density functional simulations of pressurized Mg-Zn and Al-Zn alloys Binary Mg-Zn and Al-Zn alloys have been investigated theoretically under static isotropic pressure. The stable phases of these binaries on both initially hexagonal-close-packed (hcp) and face-centered-cubic (fcc) lattices have been determined by utilizing an iterative approach that uses a configurational cluster expansion method, Monte Carlo search algorithm, and density functional theory (DFT) calculations. Based on 64-atom models, it is shown that the most stable phases of the Mg-Zn binary alloy under ambient condition are ${\mathrm{MgZn}}_{3}$, ${\mathrm{Mg}}_{19}{\mathrm{Zn}}_{45}$, $\mathrm{MgZn}$, and ${\mathrm{Mg}}_{34}{\mathrm{Zn}}_{30}$ for the hcp lattice, and ${\mathrm{MgZn}}_{3}$ and $\mathrm{MgZn}$ for the fcc lattice, whereas the Al-Zn binary is energetically unfavorable throughout the entire composition range for both the hcp and fcc lattice symmetries under all pressure conditions. By applying an isotropic pressure in the hcp lattice, ${\mathrm{Mg}}_{19}{\mathrm{Zn}}_{45}$ turns into an unstable phase at $P\ensuremath{\approx}10\phantom{\rule{0.28em}{0ex}}\mathrm{GPa}$, a new stable phase ${\mathrm{Mg}}_{3}\mathrm{Zn}$ appears at $P\ensuremath{\gtrsim}20\phantom{\rule{0.28em}{0ex}}\mathrm{GPa}$, and ${\mathrm{Mg}}_{34}{\mathrm{Zn}}_{30}$ becomes unstable for $P\ensuremath{\gtrsim}30\phantom{\rule{0.28em}{0ex}}\mathrm{GPa}$. For the fcc lattice, the ${\mathrm{Mg}}_{3}\mathrm{Zn}$ phase weakly touches the convex hull at $P\ensuremath{\gtrsim}20\phantom{\rule{0.28em}{0ex}}\mathrm{GPa}$ while the other stable phases remain intact up to $\ensuremath{\approx}120\phantom{\rule{0.28em}{0ex}}\mathrm{GPa}$. Furthermore, making use of the obtained DFT results, the bulk modulus has been computed for several compositions up to pressure values on the order of $\ensuremath{\approx}120\phantom{\rule{0.28em}{0ex}}\mathrm{GPa}$. The findings suggest that one can switch between $\mathrm{Mg}$-rich and $\mathrm{Zn}$-rich early-stage clusters simply by applying external pressure. $\mathrm{Zn}$-rich alloys and precipitates are more favorable in terms of stiffness and stability against external deformation. Isotropy ; Density functional theory ; Bulk modulus ; Binary number ; Lattice (music) ; Phase (matter) ; Cluster expansion ; Cluster (spacecraft) Magnesium Alloys: Properties and Applications ; Hydrogen Storage and Materials ; Quasicrystal Structures and Properties
Authors: John Chilleri | Yanyan He | Dmitry Bedrov | Robert M. Kirby
Source: Computational Materials Science (article, 2020-12-25)
Field: Materials Science — Materials Chemistry

Optimal allocation of computational resources based on Gaussian process: Application to molecular dynamics simulations Computer science ; Gaussian process ; Gaussian ; Mathematical optimization ; Range (aeronautics) ; Process (computing) ; System dynamics ; Resource allocation ; Molecular dynamics ; Statistical physics ; Thermal diffusivity ; Kriging ; Algorithm ; Mathematics ; Physics ; Artificial intelligence ; Materials science ; Machine learning Material Dynamics and Properties ; Probabilistic and Robust Engineering Design
Authors: Joseph H. Montoya | Kirsten T. Winther | Raul A. Flores | Thomas Bligaard | Jens S. Hummelshøj | Muratahan Aykol
Source: ChemRxiv (preprint, 2020-02-19)
Field: Materials Science — Materials Chemistry

Autonomous Intelligent Agents for Accelerated Materials Discovery We present an end-to-end computational system for autonomous materials discovery. The system aims for cost-effective optimization in large, high-dimensional search spaces of materials by adopting a sequential, agent-based approach to deciding which experiments to carry out. In choosing next experiments, agents can make use of past knowledge, surrogate models, logic, thermodynamic or other physical constructs, heuristic rules, and different exploration-exploitation strategies. We show a series of examples for (i) how the discovery campaigns for finding materials satisfying a relative stability objective can be simulated to design new agents, and (ii) how those agents can be deployed in real discovery campaigns to control experiments run externally, such as the cloud-based density functional theory simulations in this work. In a sample set of 16 campaigns covering a range of binary and ternary chemistries including metal oxides, phosphides, sulfides and alloys, this autonomous platform found 383 new stable or nearly stable materials with no intervention by the researchers. Heuristic ; Computer science ; Set (abstract data type) ; Binary number ; Autonomous agent ; Stability (learning theory) ; Work (physics) ; Ternary operation ; Range (aeronautics) ; Cloud computing ; Distributed computing ; Artificial intelligence ; Machine learning ; Engineering ; Mathematics ; Mechanical engineering ; Aerospace engineering Machine Learning in Materials Science
Authors: Kavita Gaur | Yahaira M. Cruz | José A. Santiago Espinoza | Carlos A. Morales Rueda | Sergio A. Loza-Rosas | Lauren Fernández-Vega | Josué A. Benjamín-Rivera | Adelis Álvarez | Arthur D. Tinoco
Source: Journal of Chemical Education (article, 2020-06-02)
Field: Chemistry — Electrochemistry

Exploring the pH Dependent Aqueous Speciation of Metal Complexes through UV–Vis Spectroscopy Coordination chemistry is a major component of the undergraduate inorganic chemistry curriculum and yet the presentation of the material can be cumbersome due to the limitations of the course typically being taught in one semester. Also, because of the large scope of this branch of chemistry encompassing all of the elements, the course design has not been standardized. These factors result in some important coordination chemistry themes being given insufficient development. Herein we propose a novel activity to formally introduce metal complex aqueous speciation in a holistic active-learning manner that includes a lecture component and hands-on experience. This topic has real world relevance and contextualizes many important coordination concepts. It would extend student comprehension about the intricate factors that affect metal complexation in an aqueous solution environment by focusing on the influence of pH. The activity explores the pH dependent speciation of the well-characterized interaction between Fe(III) and 2,3-dihydroxynapthalene-6-sulfonate and reveals the colorful changes in species throughout the pH range of 0 to 13. Students learn how to generate speciation plots and to understand the ultraviolet-visible (UV-Vis) electronic absorption spectroscopy of transition metal compounds to be able to analyze the source of color that they observe. Assessment of the activity was conducted with 24 students who completed a Likert scale survey and responded to open-ended questions. The activity was then applied in actual course settings in which student comprehension was quantitatively evaluated. The activity can be easily adapted to students of different stages of academic development from elementary to college students. Chemistry ; Genetic algorithm ; Aqueous solution ; Coordination complex ; Ultraviolet visible spectroscopy ; Comprehension ; Likert scale ; Metal ; Computer science ; Psychology ; Physical chemistry ; Organic chemistry ; Ecology Electrochemical Analysis and Applications ; Molecular Sensors and Ion Detection ; Chemical and Physical Properties in Aqueous Solutions
Authors: Raida Agustina | Mustaqimah | Rahmat Fadhil | Devianti Devianti
Source: Acta Technologica Agriculturae (article, 2020-11-11)
Field: Chemistry — Inorganic Chemistry

Sensory Evaluation of Pliek-U Quality Using Fuzzy-Topsis Method Abstract The purpose of this study is to apply one of the decision-making methods, namely the fuzzy-TOPSIS method, to determine the best alternative of coconut fermentation in process of making Pliek-U, which is a typical powder made of coconut and is used for traditional cooking recipes by people in Aceh Province, Indonesia. The weight of fuzzy criteria and judgments about alternative methods of coconut fermentation was used to calculate the sensory evaluation scores and Pliek-U quality ratings. It can help to determine the quality of the Pliek-U. Sensory evaluation results for the quality of Pliek-U using the fuzzy-TOPSIS method showed that the most ideal alternative of the coconut fermentation method in the process of making Pliek-U is the 10-day coconut fermentation method, because it had the highest closeness coefficient (0.7484) in contrast to the 7-day coconut fermentation method (0.5425), and 4-day coconut fermentation method (0.3291). The fuzzy-TOPSIS method utilization was beneficial for generating the sensory multi-criteria assessment calculations through weighting, so that the process of determining consumer acceptance of the product assessed became easier and faster. TOPSIS ; Fuzzy logic ; Mathematics ; Quality (philosophy) ; Weighting ; Fermentation ; Closeness ; Biotechnology ; Agricultural engineering ; Computer science ; Food science ; Engineering ; Artificial intelligence ; Chemistry ; Operations research ; Medicine ; Biology Coconut Research and Applications ; Food and Agricultural Sciences ; Sensory Analysis and Statistical Methods
Authors: Mamadou Sow | Yohan Leblois | Cécile Bodiot | C. Motzkus | Sébastien Ritoux | F. Gensdarmes
Source: Journal of Hazardous Materials (article, 2020-06-07)
Field: Materials Science — Materials Chemistry

Aerosol release fraction by concrete scarifying operations and its implications on the dismantling of nuclear facilities Aerosol ; Radioactive waste ; Environmental science ; Suction ; Aerodynamic diameter ; Waste management ; Fraction (chemistry) ; Materials science ; Chemistry ; Meteorology ; Engineering ; Physics Graphite, nuclear technology, radiation studies ; Nuclear and radioactivity studies ; Nuclear materials and radiation effects
Authors: Lei Mei | Shu‐wen An | Kong‐Qiu Hu | Lin Wang | Jipan Yu | Zhi‐wei Huang | Xiang‐he Kong | Chuanqin Xia | Zhifang Chai | Wei‐Qun Shi
Source: Angewandte Chemie (article, 2020-05-26)
Field: Chemistry — Inorganic Chemistry

Molecular Spring‐like Triple‐Helix Coordination Polymers as Dual‐Stress and Thermally Responsive Crystalline Metal–Organic Materials Abstract Elastic metal–organic materials (MOMs) capable of multiple stimuli‐responsiveness based on dual‐stress and thermally responsive triple‐helix coordination polymers are presented. The strong metal‐coordination linkage and the flexibility of organic linkers in these MOMs, rather than the 4 Å stacking interactions observed in organic crystals, causes the helical chain to act like a molecular spring and thus accounts for their macroscopic elasticity. The thermosalient effect of elastic MOMs is reported for the first time. Crystal structure analyses at different temperatures reveal that this thermoresponsiveness is achieved by adaptive regulation of the triple‐helix chains by fine‐tuning the opening angle of flexible V‐shaped organic linkers and rotation of its lateral conjugated groups to resist possible expansion, thus demonstrating the vital role of adaptive reorganization of triple‐helix metal–organic chains as a molecular spring‐like motif in crystal jumping. Triple helix ; Stacking ; Materials science ; Polymer ; Conjugated system ; Helix (gastropod) ; Coordination polymer ; Crystal structure ; Metal ; Crystallography ; Nanotechnology ; Chemical physics ; Chemistry ; Stereochemistry ; Composite material ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Supramolecular Chemistry and Complexes ; Supramolecular Self-Assembly in Materials
Authors: Tadashi Mori
Source: Synlett (article, 2020-04-24)
Field: Materials Science — Materials Chemistry

Relevance of the Entropy Factor in Stereoselectivity Control of Asymmetric Photoreactions Entropy as well as enthalpy factors play substantial roles in various chemical phenomena such as equilibrium and reactions. However, the entropy factors are frequently underestimated in most instances, particularly in synthetic chemistry. In reality, the entropy factor can be in competition with the enthalpy factor or can even be decisive in determining the overall free or activation energy change upon molecular interaction and chemical transformation, particularly where weak interactions in ground and/or excited states are significant. In this account, we overview the importance of the entropy factor in various chemical phenomena in both thermodynamics and kinetics and in the ground and excited states. It is immediately apparent that many diastereo- and enantioselective photoreactions are entropy-controlled. Recent advances on the entropy-control concept in asymmetric photoreactions are further discussed. Understanding the entropy-control concept will pave the way to improve, fine-tune, and even invert the chemo- and stereoselectivity of relevant chemical phenomena. 1 Introduction 2 Role of Entropy in Supramolecular Interactions 3 Selected Examples of Entropy-Driven Thermal Reactions 4 Classical Examples of Entropy Control in Photoreactions 5 Entropy-Driven Asymmetric Photoreactions 6 Advances in Entropy Control 7 Perspective Chemistry ; Entropy (arrow of time) ; Enthalpy ; Excited state ; Thermodynamics ; Kinetic control ; Statistical physics ; Physics ; Organic chemistry ; Atomic physics ; Catalysis Photochromic and Fluorescence Chemistry ; Organic Chemistry Cycloaddition Reactions ; Electrochemical Analysis and Applications
Authors: Shengyu Shi | Chenzhi Yao | Jie Cen | Lei Li | Guhuan Liu | Jinming Hu | Shiyong Liu
Source: Angewandte Chemie (article, 2020-07-09)
Field: Chemistry — Organic Chemistry

High‐Fidelity End‐Functionalization of Poly(ethylene glycol) Using Stable and Potent Carbamate Linkages Abstract Commercial PEG‐amine is of unreliable quality, and conventional PEG functionalization relies on esterification and etherification steps, suffering from incomplete conversion, harsh reaction conditions, and functional‐group incompatibility. To solve these challenges, we propose an efficient strategy for PEG functionalization with carbamate linkages. By fine‐tuning terminal amine basicity, stable and high‐fidelity PEG‐amine with carbamate linkage was obtained, as seen from the clean MALDI‐TOF MS pattern. The carbamate strategy was further applied to the synthesis of high‐fidelity multi‐functionalized PEG with varying reactive groups. Compared to with an ester linkage, amphiphilic PEG‐PS block copolymers bearing carbamate junction linkage exhibits preferential self‐assembly tendency into vesicles. Moreover, nanoparticles of the latter demonstrate higher drug loading efficiency, encapsulation stability against enzymatic hydrolysis, and improved in vivo retention at the tumor region. Carbamate ; Surface modification ; Ethylene glycol ; Chemistry ; Combinatorial chemistry ; Amine gas treating ; PEG ratio ; Copolymer ; Amphiphile ; Hydrolysis ; Polymer chemistry ; Organic chemistry ; Polymer Advanced Polymer Synthesis and Characterization ; Nanoparticle-Based Drug Delivery ; Polymer Surface Interaction Studies
Authors: Yuping Yuan | Kin-Cheung Lo | Lap Szeto | Ying N. Chan
Source: The Journal of Organic Chemistry (article, 2020-04-21)
Field: Chemistry — Organic Chemistry

Synthesis of Pyrazinopyrazine-Fused Azaacenes through Direct Condensation Reactions between Quinoxalinediamine and Diketones We report the synthesis of a new type of pyrazinopyrazine-fused azaacene molecules by a simple and versatile procedure. 6,9-Dihexyldithieno[3,2-f:2',3'-h]quinoxaline-2,3-diamine was synthesized through the condensation between 2,7-dihexylbenzo[1,2-b:6,5-b']dithiophene-4,5-diamine and bis(2,2,2-trifluoroethyl) oximidate. A series of derivatized molecules with extended two-dimensional aromatic fused-ring structures could be obtained by simple condensation reactions between the quinoxalinediamine intermediate and various diketones. The reaction was proved to be effective for the construction of tetrazaacene derivatives with extended heterocyclic aromatic ring systems. The molecules obtained exhibit low-lying LUMO levels that can be fine-tuned by modifying the molecular structure. Crystallographic results showed that in a solid state, the molecules form "brick wall" structures with a close π-π stacking mode. The stacking between the π-ring systems in the molecules could be further enhanced by expanding the large 2D planar-conjugated structure. Chemistry ; Molecule ; Stacking ; Diamine ; Ring (chemistry) ; Quinoxaline ; Conjugated system ; Condensation reaction ; Condensation ; Crystallography ; HOMO/LUMO ; Stereochemistry ; Computational chemistry ; Polymer chemistry ; Organic chemistry ; Polymer ; Catalysis Synthesis and Biological Evaluation ; Synthesis and Characterization of Heterocyclic Compounds ; Synthesis and Reactivity of Heterocycles
Authors: Vini Singh
Source: Journal of Flow Chemistry (article, 2020-11-16)
Field: Materials Science — Electronic, Optical and Magnetic Materials

3D-printed device for synthesis of magnetic and metallic nanoparticles Materials science ; Superparamagnetism ; Nanotechnology ; Nanoparticle ; Nanomaterials ; Fluidics ; Reagent ; Magnetite ; Microfluidics ; Magnetic nanoparticles ; Metal ; Nanochemistry ; Iron oxide nanoparticles ; Chemical engineering ; Magnetic field ; Metallurgy ; Chemistry ; Organic chemistry Gold and Silver Nanoparticles Synthesis and Applications ; Nanomaterials and Printing Technologies ; Quantum Dots Synthesis And Properties
Authors: Yuefeng Huang | Dengke Ma | Patrick W. Turner | Gavin Donnelly | Joel Katzen | William Hendren | J. M. Gregg | R. M. Bowman | Lifa Zhang | Gang Zhang | Fumin Huang
Source: Nanoscale Advances (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

Customizing the reduction of individual graphene oxide flakes for precise work function tuning with meV precision Being able to precisely control the reduction of two-dimensional graphene oxide films will open exciting opportunities for tailor-making the functionality of nanodevices with on-demand properties. Here we report the meticulously controlled reduction of individual graphene oxide flakes ranging from single to seven layers through controlled laser irradiation. It is found that the reduction can be customized in such a precise way that the film thickness can be accurately thinned with sub-nanometer resolution, facilitated by extraordinary temperature gradients >10<sup>2</sup> K nm<sup>-1</sup> across the interlayers of graphene oxide films. Such precisely controlled reduction provides important pathways towards precision nanotechnology with custom-designed electrical, thermal, optical and chemical properties. We demonstrate that this can be exploited to fine tune the work function of graphene oxide films with unprecedented precision of only a few milli electronvolts. Graphene ; Oxide ; Reduction (mathematics) ; Work function ; Work (physics) ; Function (biology) ; Nanotechnology ; Materials science ; Laser ; Optoelectronics ; Physics ; Optics ; Engineering ; Mechanical engineering ; Mathematics ; Metallurgy Graphene research and applications ; Diamond and Carbon-based Materials Research ; Nanowire Synthesis and Applications
Authors: Rebeca Sola‐Llano | Ainhoa Oliden‐Sánchez | Almudena Alfayate | Luis Gómez‐Hortigüela | Joaquı́n Pérez-Pariente | Teresa Arbeloa | Johan Hofkens | Eduard Fron | Virginia Martínez‐Martínez
Source: Nanomaterials (article, 2020-06-16)
Field: Materials Science — Materials Chemistry

White Light Emission by Simultaneous One Pot Encapsulation of Dyes into One-Dimensional Channelled Aluminophosphate By simultaneous occlusion of rationally chosen dyes, emitting in the blue, green and red region of the electromagnetic spectrum, into the one-dimensional channels of a magnesium-aluminophosphate with AEL-zeolitic type structure, MgAPO-11, a solid-state system with efficient white light emission under UV excitation, was achieved. The dyes herein selected-acridine (AC), pyronin Y (PY), and hemicyanine LDS722-ensure overall a good match between their molecular sizes and the MgAPO-11 channel dimensions. The occlusion was carried out via the crystallization inclusion method, in a suitable proportion of the three dyes to render efficient white fluorescence systems by means of fine-tuned FRET (fluorescence resonance energy transfer) energy transfer processes. The FRET processes are thoroughly examined by the analysis of fluorescence decay traces using the femtosecond fluorescence up-conversion technique. Förster resonance energy transfer ; Fluorescence ; Femtosecond ; Materials science ; Excitation ; White light ; Photochemistry ; Energy transfer ; Analytical Chemistry (journal) ; Chemistry ; Optoelectronics ; Optics ; Laser ; Molecular physics ; Physics Luminescence and Fluorescent Materials ; Conducting polymers and applications ; Carbon and Quantum Dots Applications
Authors: Hongfeng Gao | Yanli Sun | Jinpeng Zhang | Qiang Wang | Yuhua Wu | Hongcun Bai
Source: Physica E Low-dimensional Systems and Nanostructures (article, 2020-11-20)
Field: Chemistry — Organic Chemistry

Understanding endohedral behaviors of ten-electron atomic and cluster system inside C60 from first-principles Fullerene ; Endohedral fullerene ; Cluster (spacecraft) ; Density functional theory ; Chemical physics ; Cationic polymerization ; Electron ; Electron affinity (data page) ; Atomic physics ; Nanotechnology ; Materials science ; Molecular orbital ; Chemistry ; Computational chemistry ; Molecule ; Physics ; Organic chemistry Fullerene Chemistry and Applications ; Boron and Carbon Nanomaterials Research ; Graphene research and applications
Authors: M. Jiménez-Francisco | J.G. Carrillo | L.A. Garcı́a-Cerda
Source: Journal of Applied Polymer Science (article, 2020-07-15)
Field: Chemistry — Organic Chemistry

Mechanochemical tuning of molecular weight distribution of styrene homopolymers as postpolymerization modification in solvent‐free solid‐state Abstract Mechanochemical degradation by planetary ball milling (PM) is used for postpolymerization modification of styrene homopolymers (PS). A complete factorial design was chosen to study the effect of radical scavengers, milling time, initial molecular weight, and revolution radius ( R p ), on the shape of molecular weight distributions (MWDs) of PS. Size‐exclusion chromatography analysis shows the feasibility of fine‐tuning MWD of PS at up to 40% conversion. Distributions ranged from unimodal to bimodal in a PM with R p = 150 mm at different stage of milling, whereas in a PM with R p of 60.8 mm the adjustment of unimodal distributions is achieved. Initial polydispersity is more important to develop bimodal distributions when compared with initial molecular weight. Fourier transform infrared and X‐ray electron spectrometry analysis show some suppression of PS degradation and complete oxidation inhibition of macromolecular radicals with the incorporation of radical scavengers, which we considered as additional aids when adjusting the MWDs. Dispersity ; Molar mass distribution ; Fourier transform infrared spectroscopy ; Materials science ; Styrene ; Size-exclusion chromatography ; Factorial experiment ; Radical ; Solvent ; Polymer chemistry ; Degradation (telecommunications) ; Chemical engineering ; Copolymer ; Chemistry ; Organic chemistry ; Polymer ; Composite material Advanced Polymer Synthesis and Characterization ; Polymer composites and self-healing ; Polymer Nanocomposites and Properties