jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Mohamad Shariff Shahriman | Nur Nadhirah Mohamad Zain | Sharifah Mohamad | Ninie Suhana Abdul Manan | Suhaila Mohd Yaman | Saliza Asman | Muggundha Raoov
Source: RSC Advances (article, 2018-01-01)
Field: Materials Science — Polymers and Plastics

Polyaniline modified magnetic nanoparticles coated with dicationic ionic liquid for effective removal of rhodamine B (RB) from aqueous solution Polyaniline (PANI) modified magnetic nanoparticle (MNP) nanocomposites coated with newly synthesized dicationic ionic liquid (DICAT) forming MNP-PANI-DICAT were successfully synthesized as a potential material for the removal of Rhodamine B (RB) from water samples. The synthesized material was successfully characterized using a few techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), thermo gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and transmission electron microscopy (TEM) analysis. Several parameters have been optimized to enhance the efficiency of the removal process. The adsorption kinetics were investigated and the results showed that MNP-PANI-DICAT was best fitted to a pseudo-second order model for the adsorption of RB. As for the isotherm studies, Temkin's model was found to fit well with the adsorption isotherm of RB on MNP-PANI-DICAT. Other than that, thermodynamics results showed negative values of Δ<i>G</i>° for the adsorption of RB, which indicated that the process is thermodynamically feasible, spontaneous and chemically controlled at lower temperature. The negative value of enthalpy Δ<i>H</i>° (-40.41) indicated that the adsorption was an exothermic process. The percentage removal of RB was found to be 94.7% by MNP-PANI-DICAT under optimized conditions. Adsorption ; Polyaniline ; Aqueous solution ; Rhodamine B ; Thermogravimetric analysis ; Materials science ; Fourier transform infrared spectroscopy ; Rhodamine ; Ionic liquid ; Chemical engineering ; Nuclear chemistry ; Nanoparticle ; Nanocomposite ; Enthalpy ; Chemistry ; Physical chemistry ; Organic chemistry ; Fluorescence ; Polymer ; Nanotechnology ; Composite material ; Polymerization Conducting polymers and applications ; Electrochemical sensors and biosensors ; Adsorption and biosorption for pollutant removal
Authors: Ryo Matsumoto | Zhufeng Hou | Masanori Nagao | Shintaro Adachi | Hiroshi Hara | Hiromi Tanaka | Kazuki Nakamura | Ryo Murakami | Sayaka Yamamoto | Hiroyuki Takeya | Tetsuo Irifune | Kiyoyuki Terakura | Yoshihiko Takano
Source: Science and Technology of Advanced Materials (article, 2018-12-20)
Field: Materials Science — Materials Chemistry

Data-driven exploration of new pressure-induced superconductivity in PbBi<sub>2</sub>Te<sub>4</sub> Candidate compounds for new thermoelectric and superconducting materials, which have narrow band gap and flat bands near band edges, were exhaustively searched by the high-throughput first-principles calculation from an inorganic materials database named AtomWork. We focused on PbBi<sub>2</sub>Te<sub>4</sub> which has the similar electronic band structure and the same crystal structure with those of a pressure-induced superconductor SnBi<sub>2</sub>Se<sub>4</sub> explored by the same data-driven approach. The PbBi<sub>2</sub>Te<sub>4</sub> was successfully synthesized as single crystals using a melt and slow cooling method. The core level X-ray photoelectron spectroscopy analysis revealed Pb<sup>2+</sup>, Bi<sup>3+</sup> and Te<sup>2-</sup> valence states in PbBi<sub>2</sub>Te<sub>4</sub>. The thermoelectric properties of the PbBi<sub>2</sub>Te<sub>4</sub> sample were measured at ambient pressure and the electrical resistance was also evaluated under high pressure using a diamond anvil cell with boron-doped diamond electrodes. The resistance decreased with increasing of the pressure, and pressure-induced superconducting transitions were discovered at 2.5 K under 10 GPa. The maximum superconducting transition temperature increased up to 8.4 K at 21.7 GPa. The data-driven approach shows promising power to accelerate the discovery of new thermoelectric and superconducting materials. Materials science ; Superconductivity ; Thermoelectric effect ; Electrical resistivity and conductivity ; Seebeck coefficient ; Condensed matter physics ; Diamond ; X-ray photoelectron spectroscopy ; Diamond anvil cell ; Doping ; Valence (chemistry) ; Single crystal ; Analytical Chemistry (journal) ; High pressure ; Optoelectronics ; Engineering physics ; Crystallography ; Thermal conductivity ; Nuclear magnetic resonance ; Chemistry ; Thermodynamics ; Physics ; Metallurgy Advanced Thermoelectric Materials and Devices ; Machine Learning in Materials Science ; Topological Materials and Phenomena
Authors: Yu-Hang Tang | Dongkun Zhang | George Em Karniadakis
Source: The Journal of Chemical Physics (article, 2018-01-16)
Field: Materials Science — Materials Chemistry

An atomistic fingerprint algorithm for learning <i>ab initio</i> molecular force fields Molecular fingerprints, i.e., feature vectors describing atomistic neighborhood configurations, is an important abstraction and a key ingredient for data-driven modeling of potential energy surface and interatomic force. In this paper, we present the density-encoded canonically aligned fingerprint algorithm, which is robust and efficient, for fitting per-atom scalar and vector quantities. The fingerprint is essentially a continuous density field formed through the superimposition of smoothing kernels centered on the atoms. Rotational invariance of the fingerprint is achieved by aligning, for each fingerprint instance, the neighboring atoms onto a local canonical coordinate frame computed from a kernel minisum optimization procedure. We show that this approach is superior over principal components analysis-based methods especially when the atomistic neighborhood is sparse and/or contains symmetry. We propose that the "distance" between the density fields be measured using a volume integral of their pointwise difference. This can be efficiently computed using optimal quadrature rules, which only require discrete sampling at a small number of grid points. We also experiment on the choice of weight functions for constructing the density fields and characterize their performance for fitting interatomic potentials. The applicability of the fingerprint is demonstrated through a set of benchmark problems. Pointwise ; Smoothing ; Fingerprint (computing) ; Kernel (algebra) ; Scalar (mathematics) ; Benchmark (surveying) ; Feature vector ; Tetrahedron ; Force field (fiction) Machine Learning in Materials Science ; Advanced Chemical Physics Studies ; Crystallography and molecular interactions
Authors: Yufeng Liang | David Prendergast
Source: Physical review. B./Physical review. B (article, 2018-05-23)
Field: Materials Science — Materials Chemistry

Quantum many-body effects in x-ray spectra efficiently computed using a basic graph algorithm The growing interest in using x-ray spectroscopy for refined materials characterization calls for an accurate electronic-structure theory to interpret the x-ray near-edge fine structure. In this work, we propose an efficient and unified framework to describe all the many-electron processes in a Fermi liquid after a sudden perturbation (such as a core hole). This problem has been visited by the Mahan-Nozi\'eres-De Dominicis (MND) theory, but it is intractable to implement various Feynman diagrams within first-principles calculations. Here, we adopt a nondiagrammatic approach and treat all the many-electron processes in the MND theory on an equal footing. Starting from a recently introduced determinant formalism [Phys. Rev. Lett. 118, 096402 (2017)], we exploit the linear dependence of determinants describing different final states involved in the spectral calculations. An elementary graph algorithm, breadth-first search, can be used to quickly identify the important determinants for shaping the spectrum, which avoids the need to evaluate a great number of vanishingly small terms. This search algorithm is performed over the tree-structure of the many-body expansion, which mimics a path-finding process. We demonstrate that the determinantal approach is computationally inexpensive even for obtaining x-ray spectra of extended systems. Using Kohn-Sham orbitals from two self-consistent fields (ground and core-excited state) as input for constructing the determinants, the calculated x-ray spectra for a number of transition metal oxides are in good agreement with experiments. Many-electron aspects beyond the Bethe-Salpeter equation, as captured by this approach, are also discussed, such as shakeup excitations and many-body wave function overlap considered in Anderson's orthogonality catastrophe. Graph ; Algorithm ; Quantum ; Computer science ; Theoretical computer science ; Physics ; Quantum mechanics Machine Learning in Materials Science ; X-ray Spectroscopy and Fluorescence Analysis ; Atomic and Subatomic Physics Research
Authors: Magali Dams | José Luís Dores‐Sousa | Robert‐Jan A. N. Lamers | Achim Treumann | Sebastiaan Eeltink
Source: Chromatographia (article, 2018-11-07)
Field: Chemistry — Spectroscopy

High-Resolution Nano-Liquid Chromatography with Tandem Mass Spectrometric Detection for the Bottom-Up Analysis of Complex Proteomic Samples Chemistry ; Chromatography ; Mass spectrometry ; Protein mass spectrometry ; Bottom-up proteomics ; Tandem mass spectrometry ; Sample preparation in mass spectrometry ; Top-down proteomics ; Proteome ; Proteomics ; Electrospray ionization ; Sample preparation ; Electrospray ; Resolution (logic) ; Liquid chromatography–mass spectrometry ; Analytical Chemistry (journal) ; Biochemistry Mass Spectrometry Techniques and Applications ; Advanced Proteomics Techniques and Applications ; Analytical Chemistry and Chromatography
Authors: Jan Richtár | Patricie Heinrichová | Doğukan Hazar Apaydın | Veronika Schmiedová | Cigdem Yumusak | Alexander Kovalenko | Martin Weiter | Niyazi Serdar Sariçiftçi | Jozef Krajčovič
Source: Molecules (article, 2018-09-05)
Field: Materials Science — Polymers and Plastics

Novel Riboflavin-Inspired Conjugated Bio-Organic Semiconductors Flavins are known to be extremely versatile, thus enabling routes to innumerable modifications in order to obtain desired properties. Thus, in the present paper, the group of bio-inspired conjugated materials based on the alloxazine core is synthetized using two efficient novel synthetic approaches providing relatively high reaction yields. The comprehensive characterization of the materials, in order to evaluate the properties and application potential, has shown that the modification of the initial alloxazine core with aromatic substituents allows fine tuning of the optical bandgap, position of electronic orbitals, absorption and emission properties. Interestingly, the compounds possess multichromophoric behavior, which is assumed to be the results of an intramolecular proton transfer. Conjugated system ; Intramolecular force ; Flavin group ; Materials science ; Band gap ; Atomic orbital ; Absorption (acoustics) ; Combinatorial chemistry ; Organic semiconductor ; Nanotechnology ; Chemistry ; Photochemistry ; Optoelectronics ; Organic chemistry ; Physics ; Polymer Conducting polymers and applications ; Supramolecular Self-Assembly in Materials ; Advanced Sensor and Energy Harvesting Materials
Authors: Ruchi Jain | Chinnakonda S. Gopinath
Source: ACS Applied Materials & Interfaces (article, 2018-11-07)
Field: Materials Science — Materials Chemistry

New Strategy toward a Dual Functional Nanocatalyst at Ambient Conditions: Influence of the Pd–Co Interface in the Catalytic Activity of Pd@Co Core–Shell Nanoparticles Bimetallic nanostructures with a combination of noble and nonnoble metals hold promise for improving catalyst activity and selectivity. Here, we report the synthesis of Pd@Co (PC) core-shell morphology nanoparticles with three different ratios of palladium (Pd) and cobalt (Co), and a possibility to fine tune the ratio of core and shell thickness. PC exhibits superior and selective hydrogenation as well as oxidation catalytic activity at ambient or near-ambient conditions. Various characterization techniques have been employed to confirm the core-shell morphology. Without any pre-treatment or activation, fresh catalysts with different Pd to Co ratios, that is, 2:1, 1:1, and 1:2, were subjected to olefin (phenylacetylene) hydrogenation and oxidation (styrene to styrene oxide) reaction. The catalytic activity results demonstrate that the 1:1 ratio of Pd/Co is the most active composition for controlled and stepwise reduction of phenyl acetylene to styrene and then to ethyl benzene; 1:1 Pd/Co shows 100% styrene conversion in 30 min. with an order of magnitude higher turnover frequency than other catalysts. The 1:1 PC ratio is also the most active composition for selective oxidation of styrene to styrene oxide. NAPXPS (near-ambient pressure XPS) results show that the active sites for catalytic C═C hydrogenation and oxidation reaction are Co<sup>0</sup> and Co<sup>3+</sup>, respectively. However, the superior catalytic performance can be attributed to Co<sup>0</sup> (for reduction) or Co<sup>3+</sup> (for oxidation), and the Pd-Co interface plays a critical role in stabilizing the required functional character. NAPXPS results confirm that the superior catalytic performance can be attributed not only to Co<sup>0</sup> or Co<sup>3+</sup>, but also to the Pd-Co interface. The electronic effect and synergism between Co and Pd helps Co to stabilize in different oxidation states depending on the reaction conditions, and making it a dual functional catalyst. Catalysis ; Styrene ; Materials science ; Bimetallic strip ; Phenylacetylene ; Olefin fiber ; Styrene oxide ; Palladium ; Nanomaterial-based catalyst ; Nanoparticle ; Cobalt ; Catalytic oxidation ; Selectivity ; Oxide ; Chemical engineering ; Inorganic chemistry ; Copolymer ; Chemistry ; Organic chemistry ; Nanotechnology Catalytic Processes in Materials Science ; Nanomaterials for catalytic reactions ; Electrocatalysts for Energy Conversion
Authors: Sergey S. Maklakov | Victor I. Polozov | Sergey A. Maklakov | Alexey D. Mishin | Ilya A. Ryzhikov | Alexander L. Trigub | V. A. Amelichev | К. И. Маслаков | V. N. Kisel
Source: Journal of Alloys and Compounds (article, 2018-06-02)
Field: Materials Science — Polymers and Plastics

Post-deposition annealing of thin RF magnetron sputter-deposited VO2 films above the melting point Thin film ; Materials science ; Annealing (glass) ; Sputter deposition ; Crystallite ; Nanocrystalline material ; Sputtering ; Cavity magnetron ; Grain size ; Analytical Chemistry (journal) ; Optoelectronics ; Mineralogy ; Metallurgy ; Nanotechnology ; Chemistry Transition Metal Oxide Nanomaterials ; Ga2O3 and related materials ; Gas Sensing Nanomaterials and Sensors
Authors: Roger D. Johnson | D. D. Khalyavin | Pascal Manuel | Ling Zhang | Kazunari Yamaura | Alexei А. Belik
Source: Physical review. B./Physical review. B (article, 2018-09-19)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Magnetic structures of the rare-earth quadruple perovskite manganites <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>R</mml:mi><mml:msub><mml:mi>Mn</mml:mi><mml:mn>7</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>12</mml:mn></mml:msub></mml:mrow></mml:math> We report a neutron powder diffraction study of $R{\mathrm{Mn}}_{7}{\mathrm{O}}_{12}$ quadruple perovskite manganites with $R=\mathrm{La}$, Ce, Nd, Sm, and Eu. We show that in all measured compounds concomitant magnetic ordering of the $A$ and $B$ manganese sublattices occurs on cooling below the N\'eel temperature. The respective magnetic structures are collinear, with one uncompensated ${\mathrm{Mn}}^{3+}$ moment per formula unit as observed in bulk magnetization measurements. We show that both ${\mathrm{LaMn}}_{7}{\mathrm{O}}_{12}$ and ${\mathrm{NdMn}}_{7}{\mathrm{O}}_{12}$ undergo a second magnetic phase transition at low temperature, which introduces a canting of the $B$-site sublattice moments that is commensurate in ${\mathrm{LaMn}}_{7}{\mathrm{O}}_{12}$ and incommensurate in ${\mathrm{NdMn}}_{7}{\mathrm{O}}_{12}$. This spin canting is consistent with a magnetic instability originating in the $B$-site orbital order. Furthermore, ${\mathrm{NdMn}}_{7}{\mathrm{O}}_{12}$ displays a third magnetic phase transition at which long-range ordering of the Nd sublattice modifies the periodicity of the incommensurate spin canting. Our results demonstrate a rich interplay between transition-metal magnetism, orbital order, and the crystal lattice, which may be fine-tuned by cation substitution and rare-earth magnetism. Magnetism ; Spin canting ; Physics ; Condensed matter physics ; Neutron diffraction ; Magnetic moment ; Crystallography ; Perovskite (structure) ; Magnetization ; Manganite ; Phase transition ; Crystal structure ; Materials science ; Ferromagnetism ; Chemistry ; Magnetic field ; Quantum mechanics Magnetic and transport properties of perovskites and related materials ; Advanced Condensed Matter Physics ; Multiferroics and related materials
Authors: Jonathan R. Hunt | Cindy Tseng | Jahan M. Dawlaty
Source: Faraday Discussions (article, 2018-12-14)
Field: Chemistry — Physical and Theoretical Chemistry

Donor–acceptor preassociation, excited state solvation threshold, and optical energy cost as challenges in chemical applications of photobases Photobases are molecules with increased pKa in the excited state that can serve to transduce light energy into proton removal capability. They can be used to control chemical reactions using light, such as removing protons from a catalytic site in reactions that are rate-limited by proton transfer. We identify and explore several major challenges toward their practical applications. Two important challenges are the need for pre-association (or ground state hydrogen bonding) between the proton donor and the photobase, and the need for excited state solvation of the photogenerated products. We investigate these two challenges with the photobase 5-methoxyquinoline as the proton acceptor and a low-pKa alcohol, 2,2,2-trifluoroethanol, as the proton donor. We vary the concentration of the donor in a background non-hydrogen-bonding solvent. Using absorption spectroscopy, we have identified that the donor-acceptor concentration ratio must exceed 100 : 1 to achieve appreciable ground state hydrogen bonding. Interestingly, emission spectroscopy reveals that the onset of ground state hydrogen bonding does not guarantee successful excited state proton transfer. It takes an additional order of magnitude increase in donor-acceptor ratio to achieve that goal, revealing that it is necessary to have excess donor molecules to reach the solvation threshold for the photogenerated products. The next challenge is reducing the large ground-excited state energy gap, which often requires UV photons to drive proton transfer. We show experimental and computational data comparing the photobasicity and optical energy gap for a few N-aromatic heterocyclic photobases. In general, we find that reducing the energy gap by increasing the conjugation size necessarily reduces photobasicity, while adding substituents of varying electron-withdrawing strength allows some fine-tuning of this effect. The combination of these two factors provide a preliminary design space for creating new photobasic molecules. Excited state ; Solvation ; Acceptor ; Energy (signal processing) ; State (computer science) ; Chemical physics ; Atomic physics ; Chemistry ; Materials science ; Physics ; Computer science ; Molecule ; Quantum mechanics ; Organic chemistry Photochemistry and Electron Transfer Studies ; Porphyrin and Phthalocyanine Chemistry ; Radical Photochemical Reactions
Authors: Inge-Willem Noordergraaf | Tori. Fourie | Patrizio Raffa
Source: Processes (review, 2018-04-02)
Field: Chemistry — Organic Chemistry

Free-Radical Graft Polymerization onto Starch as a Tool to Tune Properties in Relation to Potential Applications. A Review Grafting of acrylic monomers onto the renewable feedstock starch via free radical polymerizations has been investigated for many years. Many potential applications have been studied, such as superabsorbents, flocculants, thickening agents and so forth. It is expected that size and spacing of the grafts have a large influence on the performance of such polymers. Yet, information upon the structure-property relationships is only scarcely found in literature. Moreover, there is no clear overview of how reaction variables can be used to influence the grafted structure. In this review, an assessment has been made of the relation between the architecture of the grafts and potential applications. Then, from a selection of relevant literature data it is demonstrated that reaction variables such as the relative concentrations of initiator and monomer, have a large impact on the average size and spacing of the grafts. The emergence of controlled radical polymerizations, like Atom Transfer Radical Polymerization (ATRP) and Reversible Addition-Fragmentation chain Transfer (RAFT), is discussed, both the current status and future prospects. These methods are promising in the future of starch grafting, especially for systems where homopolymer formation may be a problem. Nevertheless, higher costs and other related issues make these advanced methods more suitable in high added-value products. Chain transfer ; Atom-transfer radical-polymerization ; Monomer ; Raft ; Polymer ; Radical polymerization ; Polymerization ; Grafting ; Polymer science ; Materials science ; Polymer chemistry ; Starch ; Chemistry ; Chemical engineering ; Organic chemistry ; Composite material Advanced Polymer Synthesis and Characterization ; Polymer Surface Interaction Studies ; biodegradable polymer synthesis and properties
Authors: Quentin Huaulmé | Alexandra Sutter | Sadiara Fall | Denis Jacquemin | Patrick Lévêque | Pascal Retailleau | Gilles Ulrich | Nicolas Leclerc
Source: Journal of Materials Chemistry C (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Versatile synthesis of α-fused BODIPY displaying intense absorption in the NIR region and high electron affinity A straightforward, highly regioselective and versatile chemical route allows the synthesis of α-fused boron dipyrromethene regioisomers. BODIPY ; Regioselectivity ; Structural isomer ; Materials science ; Boron ; Absorption (acoustics) ; Combinatorial chemistry ; Nanotechnology ; Electron ; Fluorescence ; Organic chemistry ; Chemistry ; Catalysis ; Optics Luminescence and Fluorescent Materials ; Molecular Sensors and Ion Detection ; Nanoplatforms for cancer theranostics
Authors: Alberto Abengózar | Miguel Ángel Fernández-González | David Sucunza | Luis Manuel Frutos | Antonio Salgado | Patricia García‐García | Juan J. Vaquero
Source: Organic Letters (article, 2018-08-02)
Field: Chemistry — Organic Chemistry

C–H Functionalization of BN-Aromatics Promoted by Addition of Organolithium Compounds to the Boron Atom Addition of an organolithium compound to a BN-phenanthrene with embedded B and N atoms is proposed to result in coordination of RLi to the boron atom. This coordination, supported by NMR spectroscopy and DFT calculations, increases the nucleophilicity of the system in the β position to the N atom and is therefore a useful tool for promoting regioselective C-H functionalization of BN aromatics. Chemistry ; Surface modification ; Boron ; Regioselectivity ; Phenanthrene ; Atom (system on chip) ; Nucleophile ; Organolithium compounds ; Combinatorial chemistry ; Computational chemistry ; Organic chemistry ; Catalysis ; Physical chemistry ; Ion Organoboron and organosilicon chemistry ; Coordination Chemistry and Organometallics ; Synthesis and characterization of novel inorganic/organometallic compounds