jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Munkhbayar Baasandorj | Paul Marshall | Robert L. Waterland | A. R. Ravishankara | James B. Burkholder
Source: The Journal of Physical Chemistry A (article, 2018-04-25)
Field: Chemistry — Spectroscopy

Rate Coefficient Measurements and Theoretical Analysis of the OH + (<i>E</i>)-CF<sub>3</sub>CH═CHCF<sub>3</sub> Reaction Rate coefficients, k, for the gas-phase reaction of the OH radical with ( E)-CF<sub>3</sub>CH═CHCF<sub>3</sub> (( E)-1,1,1,4,4,4-hexafluoro-2-butene, HFO-1336mzz(E)) were measured over a range of temperatures (211-374 K) and bath gas pressures (20-300 Torr; He, N<sub>2</sub>) using a pulsed laser photolysis-laser-induced fluorescence (PLP-LIF) technique. k<sub>1</sub>( T) was independent of pressure over this range of conditions with k<sub>1</sub>(296 K) = (1.31 ± 0.15) × 10<sup>-13</sup> cm<sup>3</sup> molecule<sup>-1</sup> s<sup>-1</sup> and k<sub>1</sub>( T) = (6.94 ± 0.80) × 10<sup>-13</sup>exp[-(496 ± 10)/ T] cm<sup>3</sup> molecule<sup>-1</sup> s<sup>-1</sup>, where the uncertainties are 2σ, and the pre-exponential term includes estimated systematic error. Rate coefficients for the OD reaction were also determined over a range of temperatures (262-374 K) at 100 Torr (He). The OD rate coefficients were ∼15% greater than the OH values and showed similar temperature dependent behavior with k<sub>2</sub>( T) = (7.52 ± 0.44) × 10<sup>-13</sup>exp[-(476 ± 20)/ T] and k<sub>2</sub>(296 K) = (1.53 ± 0.15) × 10<sup>-13</sup> cm<sup>3</sup> molecule<sup>-1</sup> s<sup>-1</sup>. The rate coefficients for reaction 1 were also measured using a relative rate technique between 296 and 375 K with k<sub>1</sub>(296 K) measured to be (1.22 ± 0.1) × 10<sup>-13</sup> cm<sup>3</sup> molecule<sup>-1</sup> s<sup>-1</sup>, in agreement with the PLP-LIF results. In addition, the 296 K rate coefficient for the O<sub>3</sub> + ( E)-CF<sub>3</sub>CH═CHCF<sub>3</sub> reaction was determined to be <5.2 × 10<sup>-22</sup> cm<sup>3</sup> molecule<sup>-1</sup> s<sup>-1</sup>. A theoretical computational analysis is presented to interpret the observed positive temperature dependence for the addition reaction and the significant decrease in OH reactivity compared to the ( Z)-CF<sub>3</sub>CH═CHCF<sub>3</sub> stereoisomer reaction. The estimated atmospheric lifetime of ( E)-CF<sub>3</sub>CH═CHCF<sub>3</sub>, due to loss by reaction with OH, is estimated to be ∼90 days, while the actual lifetime will depend on the location and season of its emission. Infrared absorption spectra of ( E)-CF<sub>3</sub>CH═CHCF<sub>3</sub> were measured and used to estimate the 100 year time horizon global warming potentials (GWP) of 32 (atmospherically well-mixed) and 14 (lifetime-adjusted). Mathematics ; Thermodynamics ; Physics Spectroscopy and Laser Applications ; Atmospheric chemistry and aerosols ; Atmospheric Ozone and Climate
Authors: Manjeet Kumar | Liam J. Bromhead | Zoe Anderson | Alistair R. Overy | Jonathan W. Burton
Source: Chemistry - A European Journal (article, 2018-10-19)
Field: Chemistry — Organic Chemistry

Short, Tin‐Free Synthesis of All Three Inthomycins The inthomycins are a family of structurally and biologically rich natural products isolated from Streptomyces species. Herein the implementation of a modular synthetic route is reported that has enabled the enantioselective synthesis of all three inthomycins. Key steps include Suzuki and Sonogashira cross-couplings and an enantioselective Kiyooka aldol reaction. Enantioselective synthesis ; Sonogashira coupling ; Aldol reaction ; Combinatorial chemistry ; Tin ; Stereochemistry ; Chemistry ; Organic chemistry ; Catalysis ; Palladium Synthetic Organic Chemistry Methods ; Asymmetric Synthesis and Catalysis ; Microbial Natural Products and Biosynthesis
Authors: Yanhua Gao | Haoying Chen | Nan Liu | Ruizhi Zhang
Source: Results in Physics (article, 2018-11-01)
Field: Materials Science — Materials Chemistry

Criteria for power factor improvement in thermoelectric composite Power factor enhancement in two-phase thermoelectric composites was investigated using a 2-2 slab model. The effective power factor of the composite can be greater than both components without any interfacial effects. To achieve power factor enhancement, one phase should have a higher electrical conductivity and a higher thermal conductivity than the other, as well as a lower Seebeck coefficient. Closer power factor values of the two components gave rise to the greatest power factor enhancement of the composite. The mechanism of the enhancement was analyzed by investigating the volume ratio and temperature profile of the components. Finally, a data-driven method was used to identify suitable thermoelectric materials as components for such a power factor enhancement. Power factor ; Seebeck coefficient ; Materials science ; Thermoelectric effect ; Composite number ; Slab ; Thermal conductivity ; Thermoelectric materials ; Composite material ; Power (physics) ; Electrical resistivity and conductivity ; Thermoelectric generator ; Thermodynamics ; Electrical engineering ; Physics ; Engineering ; Structural engineering Advanced Thermoelectric Materials and Devices ; Thermal properties of materials ; Thermal Radiation and Cooling Technologies
Authors: Boris M. Okrugin | Maksim Ilyash | Denis A. Markelov | Igor M. Neelov
Source: Pharmaceutics (article, 2018-08-13)
Field: Materials Science — Polymers and Plastics

Lysine Dendrigraft Nanocontainers. Influence of Topology on Their Size and Internal Structure Poly-l-ysine dendrigrafts are promising systems for biomedical applications due to their biodegradability, biocompatibility, and similarity to dendrimers. There are many papers about the use of dendrigrafts as nanocontainers for drug delivery. At the same time, the number of studies about their physical properties is limited, and computer simulations of dendrigrafts are almost absent. This paper presents the results of a systematic molecular dynamics simulation study of third-generation lysine dendrigrafts with different topologies. The size and internal structures of the dendrigrafts were calculated. We discovered that the size of dendrigrafts of the same molecular weight depends on their topology. The shape of all studied dendrigrafts is close to spherical. Density profile of dendrigrafts depends on their topology. Topology (electrical circuits) ; Biocompatibility ; Network topology ; Molecular dynamics ; Materials science ; Dendrimer ; Lysine ; Drug delivery ; Nanotechnology ; Computer science ; Chemistry ; Mathematics ; Computational chemistry ; Polymer chemistry ; Biochemistry Dendrimers and Hyperbranched Polymers ; RNA Interference and Gene Delivery ; Chemical Synthesis and Analysis
Authors: Khidhir Alhameedi | Björn Bohman | Amir Karton | Dylan Jayatilaka
Source: International Journal of Quantum Chemistry (article, 2018-02-14)
Field: Chemistry — Spectroscopy

Predicting the primary fragments in mass spectrometry using<i>ab initio</i>Roby–Gould bond indices Abstract There is currently a lack of computational methods supporting the elucidation of unknown compounds by mass spectrometry. In this study, we develop and evaluate seven different protocols, based on the ab initio Roby–Gould bond indices [Gould et al., Theor. Chem. Acc ., 2008, 119, 275] for predicting the mass‐to‐charge ratio of the highest intensity peak (base peak) in electron impact mass spectra. The protocols are applied to a dataset of 75 molecules, including five directly targeted semiochemicals. The Roby–Gould bond indices are also surveyed exhaustively, for the first time, for a dataset of 103 molecules with 682 CC bonds. For neutral species we find that the bond indices are, as may be expected, highly correlated with the bond length; for cations, although there is a correlation, the bond indices are more variable. One of our protocols, protocol MG, correctly predicts the base peak in the mass spectra for 65 out of 75 cases. The correct base peak was calculated for three out of five targeted natural products. Chemistry ; Ab initio ; Mass spectrometry ; Mass spectrum ; Molecule ; Bond length ; Computational chemistry ; Base (topology) ; Ab initio quantum chemistry methods ; Bond order ; Chromatography ; Organic chemistry ; Mathematics Mass Spectrometry Techniques and Applications ; Analytical Chemistry and Chromatography ; Metabolomics and Mass Spectrometry Studies
Authors: Elena Korol | Yuliya Kustikova
Source: E3S Web of Conferences (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Constructive systems, load-bearing and enclosing structures of high-rise buildings As the height of the building increases, loads on load-carrying structures increase dramatically, and as a result of the development of high-rise construction, several structural systems of such buildings have been developed: frame, frame-frame, cross-wall, barrel, box-type, box-to-wall ("pipe in pipe", "Trumpet in the farm"), etc. In turn, the barrel systems have their own versions: cantilever support of the ceilings on the trunk, suspension of the outer part of the overlap to the upper carrying console "hanging house" or its support by means of the walls on the lower bearing cantilever, intermediate position of the supporting cantilevers in height to the floor, from a part of floors. The object of the study are the structural solutions of high-rise buildings. The subject of the study is the layout of structural schemes of high-rise buildings, taking into account the main parameters - altitude (height), natural climatic conditions of construction, materials of structural elements and their physical and mechanical characteristics. The purpose of the study is to identify the features and systematization of structural systems of high-rise buildings and the corresponding structural elements. The results of the research make it possible, at the stage of making design decisions, to establish rational parameters for the correspondence between the structural systems of high-rise buildings and their individual elements. Cantilever ; Structural system ; Structural engineering ; Truss ; Load bearing ; Size effect on structural strength ; Engineering ; Frame (networking) ; Suspension (topology) ; Constructive ; Structural load ; Span (engineering) ; Bearing (navigation) ; High rise ; Arch ; Architectural engineering ; Computer science ; Mechanical engineering ; Process (computing) Structural mechanics and materials ; Construction Management and Sustainability
Authors: Xiaoyu Hu | Jun Ouyang | Guochang Liu | Meng-Juan Gao | Lai-Bo Song | Jianfeng Zang | Wei Chen
Source: Polymers (article, 2018-08-07)
Field: Materials Science — Polymers and Plastics

Synthesis and Characterization of the Conducting Polymer Micro-Helix Based on the Spirulina Template As one of the most interesting naturally-occurring geometries, micro-helical structures have attracted attention due to their potential applications in fabricating biomedical and microelectronic devices. Conventional processing techniques for manufacturing micro-helices are likely to be limited in cost and mass-productivity, while <i>Spirulina</i>, which shows natural fine micro-helical forms, can be easily mass-reproduced at an extremely low cost. Furthermore, considering the extensive utility of conducting polymers, it is intriguing to synthesize conducting polymer micro-helices. In this study, PPy (polypyrrole), PANI (polyaniline), and PEDOT (poly(3,4-ethylenedioxythiophene)) micro-helices were fabricated using <i>Spirulina</i><i>platensis</i> as a bio-template. The successful formations of the conducting polymer micro-helix were confirmed using scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) and Raman and X-ray diffraction (XRD) were employed to characterize the molecular structures of the conducting polymer in micro-helical forms. In the electrochemical characterization, the optimized specific capacitances for the PPy micro-helix, the PANI micro-helix, and the PEDOT micro-helix were found to be 234 F/g, 238 F/g at the scan rate of 5 mV/s, and 106.4 F/g at the scan rate of 10 mV/s, respectively. Therefore, it could be expected that other conducting polymer micro-helices with <i>Spirulina</i> as a bio-template could be also easily synthesized for various applications. Materials science ; Conductive polymer ; Polyaniline ; Fourier transform infrared spectroscopy ; Helix (gastropod) ; Polymer ; PEDOT:PSS ; Polypyrrole ; Raman spectroscopy ; Chemical engineering ; Scanning electron microscope ; Microelectronics ; Nanotechnology ; Polymer chemistry ; Composite material ; Polymerization ; Optics Conducting polymers and applications ; Advanced Sensor and Energy Harvesting Materials ; Modular Robots and Swarm Intelligence
Authors: Garikoitz Artola | Alberto Arredondo | Ana Isabel Fernández-Calvo | Javier Aldazabal
Source: Metals (article, 2018-09-06)
Field: Materials Science — Metals and Alloys

Hydrogen Embrittlement Susceptibility of R4 and R5 High-Strength Mooring Steels in Cold and Warm Seawater Hydrogen embrittlement susceptibility ratios calculated from slow strain rate tensile tests have been employed to study the response of three high-strength mooring steels in cold and warm synthetic seawater. The selected nominal testing temperatures have been 3 °C and 23 °C in order to resemble sea sites of offshore platform installation interest, such as the North Sea and the Gulf of Mexico, respectively. Three scenarios have been studied for each temperature: free corrosion, cathodic protection and overprotection. An improvement on the hydrogen embrittlement tendency of the steels has been observed when working in cold conditions. This provides a new insight on the relevance of the seawater temperature as a characteristic to be taken into account for mooring line design in terms of hydrogen embrittlement assessment. Hydrogen embrittlement ; Seawater ; Cathodic protection ; Metallurgy ; Embrittlement ; Materials science ; Mooring ; Hydrogen ; Artificial seawater ; Submarine pipeline ; Ultimate tensile strength ; Corrosion ; Geology ; Oceanography ; Chemistry ; Electrochemistry Hydrogen embrittlement and corrosion behaviors in metals ; Structural Integrity and Reliability Analysis ; Offshore Engineering and Technologies
Authors: Peipei Cen | Weize Yuan | Shuchang Luo | Xiangyu Liu | Gang Xie | Sanping Chen
Source: New Journal of Chemistry (article, 2018-11-20)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Solvent coligands fine-tuned the structures and magnetic properties of triple-bridged 1D azido-copper(<scp>ii</scp>) coordination polymers The structures and magnetic properties of three triple-bridged 1D azido–Cu(<sc>ii</sc>) coordination polymers are well-regulated by altering the coordinated alkanol molecules. Chemistry ; Copper ; Solvent ; Polymer ; Coordination polymer ; Polymer chemistry ; Stereochemistry ; Crystallography ; Nanotechnology ; Organic chemistry Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Xavier Cauchy | J.E. Klemberg-Sapieha | Daniel Therriault
Source: Advanced Engineering Materials (article, 2018-09-13)
Field: Materials Science — Materials Chemistry

Hybrid Carbon–Silver Nanofillers for Composite Coatings with Near Metallic Electrical Conductivity Polymeric composite materials are now very well established in all areas of engineering and are still increasingly being used to replace metallic counterparts. As an important advantage, composite materials hold the promise of multifunctionality, that is, fine tuning the material composition to synthetically achieve specific requirements. Among these requirements, the electrical conductivity is still limited to values orders of magnitude below those of typical metals. An approach to conductive fillers, which involves taking advantage of the favorable properties of both carbonaceous and metallic fillers to provide near metallic conductivity to the surface of carbon fiber reinforced polymer composites is herein presented by the authors. The synthesis of hybrid core‐shell high aspect ratio carbon–silver nanoparticles with a continuous silver coating, which allows both a low contact resistance between individual fillers and a greater connectivity owing to the wire‐like morphology of the particles is achieved by the authors. Incorporating the nanoparticles in an epoxy matrix yields a conductivity of 2.5 × 10 5 S m −1 at a loading of 6.3 vol% for a corresponding material density is of 1.9 g cm −3 . The conductivity reached is high enough even to divert emulated lightning strike energy. Materials science ; Composite material ; Composite number ; Electrical conductor ; Conductivity ; Epoxy ; Coating ; Carbon fibers ; Electrical resistivity and conductivity ; Nanoparticle ; Metal ; Carbon black ; Filler (materials) ; Nanotechnology ; Metallurgy ; Natural rubber Carbon Nanotubes in Composites ; Advanced Sensor and Energy Harvesting Materials ; Electromagnetic wave absorption materials
Authors: Jean Rodríguez | Adrien Quintard
Source: CHIMIA International Journal for Chemistry (article, 2018-09-01)
Field: Chemistry — Inorganic Chemistry

Discovery of Eco-compatible Synthetic Paths by a Multi-catalysis Approach This article summarizes our recent developments in the discovery of multi-catalytic reactions. By efficiently taking the best from different worlds, the combination of several catalytic principles allows the invention of eco-compatible transformations rapidly assembling simple building blocks into elaborated enantioenriched molecules. This type of approach was successfully illustrated in the synthesis of cyclohexenones, keto-diols or in the direct functionalization of allylic alcohols by an enantioselective borrowing hydrogen. In addition, mechanistic understanding of the role of the different constituents enabled the fine-tuning of the catalytic systems considerably improving the efficiency notably in terms of enantiocontrol. Enantioselective synthesis ; Catalysis ; Allylic rearrangement ; Combinatorial chemistry ; Biochemical engineering ; Simple (philosophy) ; Computer science ; Nanotechnology ; Chemistry ; Organic chemistry ; Materials science ; Engineering Asymmetric Hydrogenation and Catalysis ; Chemical Synthesis and Reactions ; Chemical Reactions and Isotopes
Authors: Ming Fang | Lianshe Fu | Sandra F. H. Correia | Rute A. S. Ferreira | Luís D. Carlos
Source: Polymers (article, 2018-04-13)
Field: Materials Science — Materials Chemistry

Highly Efficient Luminescent Polycarboxylate Lanthanide Complexes Incorporated into Di-Ureasils by an In-Situ Sol—Gel Process In order to prepare efficient luminescent organic⁻inorganic hybrid materials embedded with a lanthanide (Ln<sup>3+</sup>) complex with polycarboxylate ligands, Ln<sup>3+</sup>-doped di-ureasils with 4,4-oxybis(benzoic acid) and 1,10-phenanthroline ligands were synthesized via an in-situ sol⁻gel route. The resulting hybrids were structurally, thermally, and optically characterized. The energy levels of the ligands and the host-to-ion and ligand-to-ion energy transfer mechanisms were investigated (including DFT/TD⁻DFT calculations). The results show that these Ln<sup>3+</sup>-based di-ureasil hybrids exhibit promising luminescent features, e.g., Eu<sup>3+</sup>-based materials are bright red emitters displaying quantum yields up to 0.50 ± 0.05. The luminescent color can be fine-tuned either by selection of adequate Ln<sup>3+</sup> ions or by variation of the excitation wavelength. Accordingly, white light emission with CIE coordinates of (0.33, 0.35) under 310 nm irradiation was obtained. Lanthanide ; In situ ; Sol-gel ; Luminescence ; Materials science ; Process (computing) ; Chemical engineering ; Polymer chemistry ; Chemistry ; Nanotechnology ; Organic chemistry ; Computer science ; Optoelectronics ; Ion Lanthanide and Transition Metal Complexes ; Metal-Organic Frameworks: Synthesis and Applications ; Polyoxometalates: Synthesis and Applications
Authors: Abdul‐Hackam Ranneh | Hiroyasu Takemoto | Shunya Sakuma | Aziz Awaad | Takahiro Nomoto | Yuki Mochida | Makoto Matsui | Keishiro Tomoda | Mitsuru Naito | Nobuhiro Nishiyama
Source: Angewandte Chemie (article, 2018-03-07)
Field: Materials Science — Surfaces, Coatings and Films

An Ethylenediamine‐based Switch to Render the Polyzwitterion Cationic at Tumorous pH for Effective Tumor Accumulation of Coated Nanomaterials Abstract Polyzwitterions are employed as coating polymers for biomaterials to induce an antifouling property on the surface. Fine‐tuning the betaine structure switches the antifouling property to be interactive with anionic tissue constituents in response to a tumorous pH gradient. The ethylenediamine moiety in the carboxybetaine enabled stepwise protonation and initiated the di‐protonation process around tumorous pH (6.5). The net charge of the developed polyzwitterion (PGlu(DET‐Car)) was thus neutral at pH 7.4 for antifouling, but was cationic at pH 6.5 for interaction with anionic constituents. Quantum dots coated with PGlu(DET‐Car) exhibited comparable stealth and enhanced tumor accumulation relative to the PEG system. The present study provides a novel design of smart switchable polyzwitterion based on a precise control of the net charge. Cationic polymerization ; Protonation ; Chemistry ; Ethylenediamine ; Biofouling ; Moiety ; Nanomaterials ; Polymer ; Betaine ; Coating ; Combinatorial chemistry ; Polymer chemistry ; Chemical engineering ; Nanotechnology ; Organic chemistry ; Membrane ; Materials science ; Ion Polymer Surface Interaction Studies ; Nanoparticle-Based Drug Delivery ; Nanoplatforms for cancer theranostics
Authors: Joerg Ressel | O. Seewald | Wolfgang Bremser | Hans-Peter Reicher | Oliver I. Strube
Source: Progress in Organic Coatings (article, 2018-08-04)
Field: Materials Science — Materials Chemistry

Low friction poly(amide-imide) coatings with silicones as tethered liquids Materials science ; Lubricant ; Polymer ; Copolymer ; Composite material ; Imide ; Lubrication ; Copper ; Wax ; Covalent bond ; Polymer chemistry ; Chemical engineering ; Organic chemistry Diamond and Carbon-based Materials Research ; Metal and Thin Film Mechanics ; Tribology and Wear Analysis
Authors: Nishant Tripathi | Vladimir Pavelyev | S. S. Islam
Source: International nano letters. (article, 2018-05-15)
Field: Materials Science — Materials Chemistry

Tunable growth of single-wall CNTs by monitoring temperature increasing rate We report here new aspects of CNT growth by CVD system where temperature increasing rate plays a key role in controlling the diameter, structural quality, and yield of CNTs. Temperature increasing rates were used in the range 100–600 °C/h and growth morphology was constantly monitored at every step by HRTEM, FESEM and Raman spectroscopy. Morphology as well as structural quality of CNTs is sharply enhanced with the increase in temperature increasing rate, and it is found that the onset of SWNTs growth starts at 600 °C/h. In this work, we also proposed that the diameter of grown CNTs is independent from the size of catalyst particles used for initiation of CNTs growth unlike the conventional concept in the field of CNTs growth. Materials science ; Nanochemistry ; High-resolution transmission electron microscopy ; Raman spectroscopy ; Growth rate ; Morphology (biology) ; Nanotechnology ; Chemical engineering ; Yield (engineering) ; Carbon nanotube ; Atmospheric temperature range ; Composite material ; Transmission electron microscopy ; Optics Carbon Nanotubes in Composites ; Semiconductor materials and devices ; Diamond and Carbon-based Materials Research