Angesichts zunehmender ökologischer Probleme durch die massive Nutzung nicht biologisch abbaubarer, erdölbasierter Kunststoffe ist die Nachfrage nach neuen ökonomischen, umweltverträglichen und rec...
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Angesichts zunehmender ökologischer Probleme durch die massive Nutzung nicht biologisch abbaubarer, erdölbasierter Kunststoffe ist die Nachfrage nach neuen ökonomischen, umweltverträglichen und recyclierbaren Kunststoffmaterialien hoch. Eine mögliche Alternative stellt die bioinspirierte Synthese mineralbasierter Hybridmaterialien dar. Hier stellen wir ein auf amorphem Calciumcarbonat (ACC) basierendes Hydrogel aus sehr kleinen ACC‐Nanopartikeln vor, die durch Polyacrylsäure physikalisch vernetzt sind. Das Hydrogel ist formbar, dehnbar und selbstheilend. Durch Trocknung lassen sich feste, freistehende und transparente Objekte mit bemerkenswerten mechanischen Eigenschaften erstellen. Der ursprüngliche Hydrogel‐Zustand kann durch Quellen in Wasser vollständig wiederhergestellt werden. Das Material kann auch als Matrix für ein thermochromes Material dienen. Das hier vorgestellte Material ist ein Beispiel für eine neue Klasse von Kunststoffmaterialien, die “Mineral‐Kunststoffe”.
Recent tests performed on the D-Wave Two quantum annealer have revealed no clear evidence of speedup over conventional silicon-based technologies. Here we present results from classical parallel-tempering Monte Carlo ...
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Recent tests performed on the D-Wave Two quantum annealer have revealed no clear evidence of speedup over conventional silicon-based technologies. Here we present results from classical parallel-tempering Monte Carlo simulations combined with isoenergetic cluster moves of the archetypal benchmark problem—an Ising spin glass—on the native chip topology. Using realistic uncorrelated noise models for the D-Wave Two quantum annealer, we study the best-case resilience, i.e., the probability that the ground-state configuration is not affected by random fields and random-bond fluctuations found on the chip. We thus compute classical upper-bound success probabilities for different types of disorder used in the benchmarks and predict that an increase in the number of qubits will require either error correction schemes or a drastic reduction of the intrinsic noise found in these devices. We restrict this study to the exact ground state, however, the approach can be trivially extended to the inclusion of excited states if the success metric is relaxed. We outline strategies to develop robust, as well as hard benchmarks for quantum annealing devices, as well as any other (black box) computing paradigm affected by noise.
Although the major isomers of M@C 82 (namely M@ C 2 v (9)‐C 82 , where M is a trivalent rare‐earth metal) have been intensively investigated, the lability of the minor isomers has meant that they have been little st...
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Although the major isomers of M@C 82 (namely M@ C 2 v (9)‐C 82 , where M is a trivalent rare‐earth metal) have been intensively investigated, the lability of the minor isomers has meant that they have been little studied. Herein, the first isolation and crystallographic characterization of the minor Y@C 82 isomer, unambiguously assigned as Y@ C s (6)‐C 82 by cocrystallization with Ni(octaethylporphyrin), is reported. Unexpectedly, a regioselective dimerization is observed in the crystalline state of Y@ C s (6)‐C 82 . In sharp contrast, no dimerization occurs for the major isomer Y@ C 2 v (9)‐C 82 under the same conditions, indicating a cage‐symmetry‐induced dimerization process. Further experimental and theoretical results disclose that the regioselective dimer formation is a consequence of the localization of high spin density on a special cage‐carbon atom of Y@ C s (6)‐C 82 which is caused by the steady displacement of the Y atom inside the C s (6)‐C 82 cage.
Detailed quantitative measurement of surface dynamics during thin film growth is a major experimental challenge. Here x-ray photon correlation spectroscopy with coherent hard x rays is used in a grazing-incidence smal...
Detailed quantitative measurement of surface dynamics during thin film growth is a major experimental challenge. Here x-ray photon correlation spectroscopy with coherent hard x rays is used in a grazing-incidence small-angle x-ray scattering (i.e., Co-GISAXS) geometry as a tool to investigate nanoscale surface dynamics during sputter deposition of a-Si and a-WSi2 thin films. For both films, kinetic roughening during surface growth reaches a dynamic steady state at late times in which the intensity autocorrelation function g2(q,t) becomes stationary. The g2(q,t) functions exhibit compressed exponential behavior at all wavenumbers studied. The overall dynamics are complex, but the most surface sensitive sections of the structure factor and correlation time exhibit power law behaviors consistent with dynamical scaling.
Polymer aerogels have been attractive materials for applications in chemical sensors, thermal insulations, chemical adsorbents, catalysts or catalytic carriers, and space explorations since they were invented in the *...
Polymer aerogels have been attractive materials for applications in chemical sensors, thermal insulations, chemical adsorbents, catalysts or catalytic carriers, and space explorations since they were invented in the ***, the flammability of polymer matrices limits their potential applications in some significant ***, the polymer aerogel materials require modifications to decrease their flammability through the addition of flame-retardant compounds.
Low‐cost, single‐step synthesis of hollow nanotubes of N‐doped carbon deposited on CoS is enabled by the simultaneous use of three functionalities of polyacrylonitrite (PAN) nanofibers: 1) a substrate for loading a...
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Low‐cost, single‐step synthesis of hollow nanotubes of N‐doped carbon deposited on CoS is enabled by the simultaneous use of three functionalities of polyacrylonitrite (PAN) nanofibers: 1) a substrate for loading active materials, 2) a sacrificial template for creating hollow tubular structures, and 3) a precursor for in situ nitrogen doping. The N‐doped carbon in hollow tubes of CoS provides a high‐capacity anode of long cycle life for a rechargeable Li‐ion or Na‐ion battery cell that undergoes the conversion reaction 2 A + +2 e − +CoS →Co+A 2 S with A=Li or Na.
Carbon aerogels (Cas) with continuous porosity, high surface area and excellent electrical conductivity are promising for developing catalyst supports, adsorbent and electrode ***, a new type of Fe2O3 nanoparticles on...
Carbon aerogels (Cas) with continuous porosity, high surface area and excellent electrical conductivity are promising for developing catalyst supports, adsorbent and electrode ***, a new type of Fe2O3 nanoparticles on KOH actived graphene/polyimide-based carbon aerogel (Fe2O3/G-PI based CA) hybrids have been facilely synthesized via the synthesis of water soluble polyimide precursor, poly(amic acid) (PAA), the mixture of graphene oxide (GO), PAA and KOH,sol-gel, freeze-drying, imidization, high-temperature carbonization and one-step solvothermal reaction.
The lithium–air battery has been proposed as the next‐generation energy‐storage device with a much higher energy density compared with the conventional lithium‐ion battery. However, lithium–air batteries currentl...
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The lithium–air battery has been proposed as the next‐generation energy‐storage device with a much higher energy density compared with the conventional lithium‐ion battery. However, lithium–air batteries currently suffer enormous problems including parasitic reactions, low recyclability in air, degradation, and leakage of liquid electrolyte. Besides, they are designed into a rigid bulk structure that cannot meet the flexible requirement in the modern electronics. Herein, for the first time, a new family of fiber‐shaped lithium–air batteries with high electrochemical performances and flexibility has been developed. The battery exhibited a discharge capacity of 12 470 mAh g −1 and could stably work for 100 cycles in air; its electrochemical performances were well maintained under bending and after bending. It was also wearable and formed flexible power textiles for various electronic devices.
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