jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Tong Gao
Source:  (article, 2021-01-09)
Field: Chemistry — Inorganic Chemistry

Constructing Crystalline Molecular Dipolar Rotor Arrays with Ultra-Large Dipole Moments We aim to synthesize a series of dipolar crystalline molecular rotors with substituted benzene rotators in an extended structure. By taking advantage of the porosity of metal organic frameworks (MOFs), we can fine-tune a large cavity for the dynamic rotator to rotate efficiently in the crystalline phase. This would not only allow one to further investigate the dipole-dipole interactions in these dipolar rotors but also their dynamics at various temperatures. We presume that the ideal MOF pillars with ultra-large dipole moment will allow one to investigate the ferroelectric or antiferroelectric properties even at room temperature. In addition, dynamic study of the rotors under an applied AC field will also be studied in order to further investigate any leads regarding externally controlled rotations in the crystalline phase. Dipole ; Ferroelectricity ; Antiferroelectricity ; Moment (physics) ; Phase (matter) ; Chemical physics ; Materials science ; Relaxation (psychology) ; Rotor (electric) ; Condensed matter physics ; Field (mathematics) ; Molecular dynamics ; Physics ; Chemistry ; Dielectric ; Computational chemistry ; Optoelectronics ; Classical mechanics ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Organic and Molecular Conductors Research ; Luminescence and Fluorescent Materials
Authors: Matus Varhanik | Miroslav Piska
Source: MM Science Journal (article, 2021-05-25)
Field: Materials Science — Materials Chemistry

THE MACHINABILITY OF INC 718 BY CERAMIC INSERTS The work deals with a machinability of Inconel® 718 construction material (hereafter referred to as “INC 718”). This chromium-nickel alloy has an austenitic structure, which in conjunction with its low thermal conductivity is one of the causes of a worse machinability. The aim of the work was to increase the productivity of the roughing turning process. There are more ways to improve the machinability of the INC 718, starting from the heat treatment of the material and ending with the application of process fluids. This work is based on real requirements of a company and therefore the possibilities of elimination of the worse machinability were limited by economic and technological aspects. For this reason, the main tool for increasing the productivity of the machining process was changing the material of the cutting tool and fine-tuning of the cutting conditions. In another part of the work, an evaluation of the experimentally determined force ratios of the reference and newly designed technology, which is the basis for the stress-strain analysis, have been made. The conclusion of the research highlights the newly designed process in terms of machining times and the volume of material achieved per unit of the cutting edge durability. Machinability ; Inconel ; Machining ; Materials science ; Metallurgy ; Process (computing) ; Ceramic ; Mechanical engineering ; Alloy ; Computer science ; Engineering Metal Alloys Wear and Properties ; Advanced machining processes and optimization ; Surface Treatment and Coatings
Authors: Aleksandra Tobolska
Source: MDPI (MDPI AG) (article, 2021-06-30)
Field: Chemistry — Spectroscopy

Metal&amp;ndash;Peptide Complexes&amp;mdash;A Novel Class of Molecular Receptors for Electrochemical Phosphate Sensing Amyloid-&amp;beta; (A&amp;beta;) peptides are crucial in the pathology of Alzheimer&amp;rsquo;s disease. On the other hand, their metal complexes possess distinctive coordination properties that could be of great importance in the selective recognition of (bio)analytes, such as anions. Here, we report a novel group of molecular receptors for phosphate anions recognition: metal&amp;ndash;peptide complexes of A&amp;beta; peptides, which combine features of synthetic inorganic ligands and naturally occurring binding proteins. The influence of the change in the metal ion center on the coordination and redox properties of binary Cu(II)/Ni(II)-A&amp;beta; complexes, as well as the affinity of these complexes towards phosphate species, were analyzed. This approach offers the possibility of fine-tuning the receptor affinity for desired applications. Peptide ; Chemistry ; Metal ; Receptor ; Combinatorial chemistry ; Molecular recognition ; Metal ions in aqueous solution ; Phosphate ; Molecule ; Biochemistry ; Organic chemistry Molecular Sensors and Ion Detection ; Chemical Synthesis and Analysis ; Polyoxometalates: Synthesis and Applications
Authors: Frederik Luessmann | Jana Hartmann | H.-H. Wehmann | Constantin Hilbrunner | J. Malindretos | A. Rizzi | Stefanie Kroker | A. Waag
Source:  (article, 2021-03-04)
Field: Materials Science — Surfaces, Coatings and Films

Towards optically pumped GaN-based high-contrast grating V(E)CSELs In this study we present the novel approach of GaN-based high-contrast grating (HCG) mirrors as highly reflective top mirrors in GaN vertical-(external)-cavity surface-emitting lasers [V(E)CSELs]. These mirrors can well be integrated into a conventional process flow for GaN-based VECSEL devices – in contrast to conventional Bragg mirrors. Results of thorough growth experiments performed to reliably fabricate high quality cavity structures with well-defined and fine-tuned optical properties will be reported. The properties of HCG mirrors have been calculated by extensive optical device simulations. Properties of HCG structures have been analyzed experimentally by reflection measurements and results will be discussed with a focus on HCG design, potential material combinations, compatibility with existing process steps in GaN technology and the various ways of integration into VECSEL structures. Materials science ; Optics ; Grating ; Optoelectronics ; High contrast ; Laser ; Reflection (computer programming) ; Computer science ; Physics Optical Coatings and Gratings ; Photonic and Optical Devices ; Semiconductor Lasers and Optical Devices
Authors: Snehal | Pallavi Kadam | Padwal | Shrinivas | Kulkarni | Mustafa Aghazadeh | Shuxi Dai | Yinyong Li | Zuliang Du | Kenneth Carter | X Lan | Y Jiang | X Liu | W Wang | D Wu | C Liu | Y Z1hang | H Zhong | S Peulon | D Lincot | M Izaki | T Omi | Ahmad Fazel Ghahramanifard | * Rouhollahi | Omid Fazlolahzadeh | Matthew Lawrence | Kolodziej | Adam | Paramaconi Rodriguez | Mohamed Shaban | Amin Hussein | Ahmed Abdel Khalek | Hany | Hamdy | Li Shaolan | Zhang Lichun | S Devan | Sylvie Beaufils | Pierre Thierry Rouillon | Jean Millet | Pierre Bideau | Jean -Paul Weiss | Anne -Lise Chopart | Dalin | Canlin Ou | Pedro | Enrique Sanchez-Jimenez | Anuja Datta | Francesca Boughey | Richard Whiter | Suman-Lata Sahonta | Sohini Kar-Narayan
Source: International Journal of Innovative Research in Physics (article, 2021-01-01)
Field: Chemistry — Electrochemistry

Electrochemical Synthesis and Morphology Investigation with Respect to Parameters on Metal, Metaloxide Composite Fine tuning proper parametric condition is the key factor to attain the required morphology on synthesis process.Perfect synthesis task can pave strong foundation towards application part such as vertical oriented, uniformed hybrid one dimension nanostructures can lead fabrication of nano electronic devices.Nanostructures in the form of zero, one and two dimensions will selectively fulfil the design aspect of transition metal oxide based electrodes for energy devices and sensors.This research paper have been examined the impact of various synthesis parameters listed as template assisted deposition, change in electrode position, deposition potential and direct deposition on copper substrate with zinc nitrate hexahydrate salt in liquid form for constant precursor concentration.Synthesis done through electrochemical deposition method using two electrode electrochemical cell with copper substrate acts as working electrode, platinum as counter electrode, Polycarbonate membrane with 200nm pores as template, for characterization Scanning Electron Microscopy, Field Emission Scanning Electron Microscopy techniques were used to obtain morphology analysis of the samples.Result revealed the morphology based on variation in synthesis parameter also shown limitation on template with random pores and narrow exposure of counter electrode.Scrutiny process of precursor concentration with respective characterization analysis of prior work was considered as reference for this work. Morphology (biology) ; Composite number ; Electrochemistry ; Materials science ; Metal ; Composite material ; Metallurgy ; Chemical engineering ; Chemistry ; Engineering ; Geology ; Electrode ; Paleontology ; Physical chemistry Electrochemical Analysis and Applications ; Conducting polymers and applications ; Corrosion Behavior and Inhibition
Authors: Shahar Tevet | Shreyas Shankar Wagle | Gadi Slor | Roey J. Amir
Source: ChemRxiv (preprint, 2021-06-01)
Field: Materials Science — Polymers and Plastics

Tuning Reactivity of Micellar Nanoreactors by Precise Adjustments of the Amphiphiles and Substrates Hydrophobicity &lt;p&gt;Polymeric assemblies, such as micelles, are gaining increasing attention due to their ability to serve as nanoreactors for the execution of organic reactions in aqueous media. The ability to conduct transformations, which have been limited to organic media, in water is essential for the further development of the important fields of green&lt;/p&gt;&lt;p&gt;catalysis and bioorthogonal chemistry, among other fields. In light of the recent progress in the expanding the scopes of reactions that can be conducted using nanoreactors, we aimed to gain deeper understanding of the roles of the hydrophobicity of both the core of micellar nanoreactors and the substrates on the reaction rates in water. Towards this goal we designed a set of metal-loaded micelles, composed of PEG-dendron amphiphiles and studied their ability to serve as nanoreactors for a palladium mediated depropargylation reaction of four substrates with different LogP values. Using dendrons as the hydrophobic block, allowed us to fine tune the lipophilicity of the dendritic end-groups and study how precise structural changes in the hydrophobicity of the amphiphiles affect the reaction rates. The kinetic data revealed linear relations between the rate constants and the hydrophobicity of the amphiphiles (estimated by the dendron’s&lt;/p&gt;&lt;p&gt;cLogP), while exponential dependence was obtained for the lipophilicity of the substrates (estimated by their LogP values). Our results demonstrate the vital contributions of the hydrophobicity of both the substrates and amphiphiles on the lipo-selectivity of nanoreactors, illustrating the potential of tuning hydrophobicity as a tool for optimizing&lt;/p&gt;&lt;p&gt;the reactivity and selectivity of nanoreactors.&lt;/p&gt; Nanoreactor ; Amphiphile ; Lipophilicity ; Micelle ; Chemistry ; Dendrimer ; Bioorthogonal chemistry ; Combinatorial chemistry ; Reactivity (psychology) ; Aqueous solution ; Organic chemistry ; Catalysis ; Click chemistry ; Copolymer ; Polymer Dendrimers and Hyperbranched Polymers ; Advanced Polymer Synthesis and Characterization ; Click Chemistry and Applications
Authors: Gianluigi De Falco | Giuseppe De Filippis | Carmela Scudieri | Luca Vitale | Mario Commodo | Patrizia Minutolo | Andrea D’Anna | Paolo Ciambelli
Source: SHILAP Revista de lepidopterología (article, 2021-04-01)
Field: Materials Science — Materials Chemistry

Production and Characterization of Nano-tio2 Coatings on Aluminium Alloy Surfaces with Improved Anticorrosion Behaviour This paper presents a one-step method for the coating of aluminium alloy surfaces with titania nanoparticles. This method is based on a highly controllable and tunable technique for the production of thin coating layers of TiO2 nanoparticles by aerosol flame synthesis and direct thermophoretic deposition. More specifically, few nm diameter TiO2 nanoparticles in the form of anatase are synthesized by flame aerosol and directly deposited as thin film by thermophoresis on aluminium alloy AA2024 samples. Submicron coatings of different thicknesses were produced by changing the total deposition time. A thermal annealing treatment was fine-tuned using UV-Vis Absorption spectroscopy and applied in order to improve the adhesion of the coating on the aluminium surface. Electrochemical polarization measurements were performed to evaluate the corrosion resistance of coated aluminium substrates. The electrochemical polarization curves showed a significant increase of the corrosion potential of coated substrates with respect to the bare aluminium and a decrease in the current density. The coatings produced with higher deposition time and so greater thickness showed the best performances in terms of corrosion resistance. Aluminium ; Nano- ; Materials science ; Characterization (materials science) ; Metallurgy ; Alloy ; Aluminium alloy ; Nanotechnology ; Composite material Corrosion Behavior and Inhibition ; Anodic Oxide Films and Nanostructures ; Metal and Thin Film Mechanics
Authors: Sambit Das | Salini Senthil | Sabyasachi Chakraborty | Raghunathan Ramakrishnan
Source: ChemRxiv (preprint, 2021-05-03)
Field: Chemistry — Organic Chemistry

All Hands on Deck: Accelerating Ab Initio Thermochemistry via Wavefunction Approximations &lt;div&gt;We accelerate the G4(MP2) composite model by fine-tuning the individual steps using resolution-of-identity and domain‐based local pair‐natural orbitals. The new variant, G4(MP2)-XP, has a low prediction error when tested on 1694 benchmark molecules. To showcase the method's relevance for large molecules, we determine and present a new reference value for the standard formation enthalpy of buckminsterfullerene. We expect G4(MP2)-XP to become the &lt;i&gt;de facto&lt;/i&gt; method for rapid and accurate production of thermochemistry big data.&lt;/div&gt; Thermochemistry ; Wave function ; Ab initio ; Benchmark (surveying) ; Atomic orbital ; Standard enthalpy of formation ; Enthalpy ; Computational chemistry ; Ab initio quantum chemistry methods ; Physics ; Chemistry ; Molecule ; Computer science ; Theoretical physics ; Atomic physics ; Thermodynamics ; Quantum mechanics ; Geology Chemical Thermodynamics and Molecular Structure ; Advanced Chemical Physics Studies ; Phase Equilibria and Thermodynamics
Authors: Jiabin Cui | Somnath Koley | Yossef E. Panfil | Adar Levi | Yonatan Ossia | Nir Waiskopf | Sergei Remennik | Meirav Oded | Uri Banin
Source: arXiv (Cornell University) (preprint, 2021-11-25)
Field: Materials Science — Materials Chemistry

Neck Barrier Engineering in Quantum Dot Dimer Molecules via Intra-Particle Ripening Coupled colloidal quantum dot (CQD) dimers represent a new class of artificial molecules composed of fused core/shell semiconductor nanocrystals. The electronic coupling and wavefunction hybridization is enabled by the formation of an epitaxial connection with a coherent lattice between the shells of the two neighboring quantum dots where the shell material and its dimensions dictate the quantum barrier characteristics for the charge carriers. Herein we introduce a colloidal approach to control the neck formation at the interface between the two CQDs in such artificial molecular constructs. This allows the tailoring of the neck barrier in pre-linked homodimers formed via fusion of multifaceted wurtzite CdSe/CdS CQDs. The effects of reaction time, temperature and excess ligands is studied. The neck filling process follows an intraparticle ripening mechanism at relatively mild reaction conditions while avoiding inter-particle ripening. The degree of surface ligand passivation plays a key role in activating the surface atom diffusion to the neck region. The degree of neck filling strongly depends also on the initial relative orientation of the two CQDs, where homonymous plane attachment allows for facile neck growth, unlike the case of heteronymous plane attachment. Upon neck-filling, the observed red-shift of the absorption and fluorescence measured both for ensemble and single dimers, is assigned to enhanced hybridization of the confined wavefunction in CQD dimer molecules, as supported by quantum calculations. The fine tuning of the particle interface introduced herein provides therefore a powerful tool to further control the extent of hybridization and coupling in CQD molecules. Quantum dot ; Chemical physics ; Molecule ; Nanoparticle ; Chemistry ; Materials science ; Nanocrystal ; Nanotechnology ; Molecular physics Quantum Dots Synthesis And Properties ; Nanocluster Synthesis and Applications ; Gold and Silver Nanoparticles Synthesis and Applications
Authors: Yuvasri Genji Srinivasulu | Nirmal Goswami | Qiaofeng Yao | Jianping Xie
Source: The Journal of Physical Chemistry (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

High-Yield Synthesis of AIE-Type Au₂₂(SG)₁₈ Nanoclusters through Precursor Engineering and Its pH-Dependent Size Transformation In recent years, ultrasmall metal nanoclusters (NCs) with aggregation-induced emission (AIE) characteristics have drawn enormous attention due to their strong photoluminescence (PL) and potential applications in many fields, such as bioimaging, diagnostics, therapeutics, and sustainable fuel production. Among all the reported AIE-type metal NCs, the red-emitting Au₂₂(SR)₁₈ NCs (where SR is a thiolate ligand) with a precise molecular formula remain as a promising candidate. Common synthetic strategies for Au₂₂(SR)₁₈ NCs (e.g., CO-reduction method) not only have relatively low synthesis yield, but also form the byproduct of Au₁₈(SR)₁₄. In addition, the lack of systematic understanding of the reaction mechanism and nontrivial postsynthesis steps greatly hinders its large-scale production. To address these issues, herein, we report a modified CO-reduction protocol to improve the yield of AIE-type Au₂₂ NCs in solution. By deconvoluting the original CO-reduction protocol into two stages, the importance of each stage can be studied in detail. By optimizing the key parameters of each stage (e.g., incubation time and temperature), the yield of Au₂₂ NCs can be significantly improved (to ∼73%). In addition, we also demonstrated the role of precursors in tailoring the size of the final NC products of the modified CO-reduction protocol. By fine-tuning the incubation time of Stage I and keeping the rest of the protocol unchanged, we can obtain either Au₁₈ or Au₂₂ NCs as the final product. Moreover, an interesting pH-dependent size transformation from Au₂₂ to Au₁₈ NCs was also observed regardless of the reaction temperature. The observed synthetic improvement and the postsynthetic size transformation can show impact on the synthesis of other AIE-type metal NCs with different sizes and compositions. Nanoclusters ; Chemistry ; Yield (engineering) ; Photoluminescence ; Ligand (biochemistry) ; Metal ; Nanoparticle ; Nanotechnology ; Combinatorial chemistry ; Chemical engineering ; Organic chemistry ; Materials science Nanocluster Synthesis and Applications ; Advanced Nanomaterials in Catalysis ; Inorganic Chemistry and Materials
Authors: Koar Chorozian | Anthi Karnaouri | Dimitrios Zouraris | Antonis Karantonis | Evangelos Topakas
Source:  (article, 2021-10-15)
Field: Materials Science — Biomaterials

A novel multi-step enzymatic process for the isolation of nanocellulose from organosolv pretreated hardwoodbiomass: insights into the key role of a newly discovered AA9 LPMO Nanocellulose is one of the most important lignocellulose-derived value added products in the emerging market of biobased polymers. Its isolation upon employment of milder, environmentally friendly processes is particularly attractive. Biocatalysis is a promising approach due to targeted and substrate-specific activity, selectivity, mild and non-toxic chemistry. Endoglucanases are the most exploited enzymes for the production of nanocellulose due to their potential to remove the less ordered amorphous regions from cellulose fibers, leaving intact the more organized, crystalline areas, thus facilitating the nanocellulose isolation without altering the cellulose surface chemistry. Moreover, accessory activities including xylanases and other hemicellulose-acting enzymes hold a key role for the isolation of nanocrystalline cellulose. The newly discovered lytic polysaccharide monooxygenases (LPMOs) are also gaining attention due to their implication in nanocellulose production. Within this context, we report the heterologous expression and production of a novel fungal C1-acting AA9 LPMO from Thermothelomyces thermophila. The enzyme was biochemically characterized for its activity on different polysaccharide substrates, while different electrochemically active compounds were tested as electron donors. The formal potential of the of the Cu(II) center in the active site of the LPMO was determined with the use of large amplitude Fourier Transform alternating current cyclic voltammetry(FTacV). Finally, the application of the enzyme together with other glycoside hydrolases on nanocellulose isolation from beechwood was studied. Starting with an initial mild oxidative organosolv pretreatment, efficient delignification was achieved, leaving behind a cellulose-rich solid fraction. An enzymatic treatment step with LPMO was then applied, followed by different sequential hydrolysis steps with cellulolytic and hemicellulolytic enzymes, thus enabling a fine-tuning of all activities with the aim to shed light on the contribution of different enzymes in each step. Both commercially available enzyme cocktails and a combination of different monoenzymes with specific activities were tested in order to assess their individual effects. Nanocellulose ; Cellulose ; Chemistry ; Hemicellulose ; Polysaccharide ; Organosolv ; Biocatalysis ; Biochemistry ; Organic chemistry ; Ionic liquid ; Catalysis Advanced Cellulose Research Studies ; Biofuel production and bioconversion ; Enzyme-mediated dye degradation
Authors: Ayuth Vejpongsa | Peerapat Thongnuek
Source: IOP Conference Series Materials Science and Engineering (article, 2021-08-01)
Field: Materials Science — Biomaterials

Effect of Thai Silk Fibroin on Mechanical Properties of Bioactive Glass Silk Fibroin Hybrid Bone Scaffolds Abstract Bioactive glass (70 mol% Si and 30% Ca; 70S30C) has been used as tissue engineering scaffolds in various research despite its brittleness due to its easy-to-replicate formula, extensive interconnected pores and natural bone bonding property of bioactive glass (BG). Thai silk fibroin (SF) is natural polymer with many desirable properties; biocompatibility, mechanical strength, biodegradability. Using BG-SF hybrid scaffolds could employ the positive effects of both bioactive glass and silk fibroin. Serving as bone scaffolds, BG-SF scaffolds must resist compression and other types of mechanical load depending on the application. This study fabricates scaffolds with various ratios of BG:SF (BG:SF; 90:10, 80:20 with 100:0 as control), and their stress-strain profiles were investigated. As expected, the scaffolds with highest BG content exhibited the curve resembling that of porous foam while the elastomeric stress-strain profile was becoming more evident when the SF content was increased. This study hence demonstrated fine-tuning mechanical properties of the BG using locally enriched SF. Fibroin ; Bioactive glass ; Biocompatibility ; SILK ; Materials science ; Composite material ; Brittleness ; Elastomer ; Composite number Silk-based biomaterials and applications ; Bone Tissue Engineering Materials ; Collagen: Extraction and Characterization