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Hydro-mechanical fault reactivation modeling based on elasto-plasticity with embedded weakness planes
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Nitrogen-tuned bonding mechanism of Li and Ti adatom embedded graphene
The effects of nitrogen defects on the bonding mechanism and resultant binding energy between the metal and graphene layer were investigated using density functional theory (DFT) calculations. For the graphitic N-doped graphene, Li adatom exhibited ionic bonding character, while Ti adatom showed features of covalent bonding similar to that of pristine graphene. However, in the cases of pyridinic and pyrrolic structures, partially covalent bonding characteristic occurred around N atoms in the process of binding with metals, and this particular bond formation enhanced the bond strength of metal on the graphene layer as much as it exceeded the cohesive energy of the metal bulk. Thus, Li and Ti metals are expected to be dispersed with atomic accuracy on the pyridinic and pyrrolic N-doped graphene layers. These results demonstrate that the bonding mechanism of metal–graphene complex can change according to the type of N defect, and this also affects the binding results. - Graphical abstract: Display Omitted - Highlights: • Nitrogen defects changed the bonding mechanism between metal and graphene. • Bonding character and binding results were investigated using DFT calculations. • Covalent bonding character occurred around pyridinic and pyrrolic N-doped graphene. • Pyridinic and pyrrolic N atoms are effective for metal dispersion on the graphene.
Evaluation of the influence of sulfur-based functional groups on the embedding of silver nanoparticles into the pores of MCM-41
The incorporation of noble metals in the pores of mesoporous silicas might produce materials with interesting catalytic and sensing capabilities, but the proper control of pore filling and the avoidance of nanoparticles migration to outside the pores are processes not yet completely understood. In this work, we evaluated the role of –SH and –SO{sub 3}H groups post-grafted into MCM-41 on the production of silver nanoparticles by using 1-butanol as reducing agent. Thiol groups were the most efficient on promoting the formation of nanoparticles within the pores. Conversely, sulfonic groups establish electrostatic interactions with silver cations that preclude the formation of nanoparticle in yields comparable to thiol groups. MCM-41 without functional groups did not have good affinity to silver and the nanoparticles are produced outside the pores. This study showed the importance on selecting an adequate surface functional group in order to obtain silver nanoparticles filling the pores of MCM-41. - Graphical abstract: Silver nanoparticles formation inside the pores of sulfur-groups functionalized mesoporous silica. - Highlights: • Silver nanoparticles formation inside the pores of mesoporous silica. • n-butanol as reducing agent of impregnated silver cations. • Tuning the silica surface properties by grafting sulfur-based functional groups. • Influence on the loading and distribution of the nanoparticles through the pores.
Synthesis, characterization, UV and dielectric properties of hexagonal disklike ZnO particles embedded in polyimides
Graphical abstract: The hexagonal disklike ZnO particles with a diameter of 300-500 nm were synthesized from zinc acetate and NaOH in water with citric acid. ZnO/polyimide composite films with different ZnO contents was prepared. The prepared zinc oxide-polyimide composites were characterized for their structure, morphology and thermal behavior. Composites with ZnO particle contents from 1 to 5 wt% show good transparency in the visible region and luminescent properties. Highlights: {yields} A series of novel ZnO/polyimide composite films with different ZnO contents was prepared. {yields} The ZnO was homogeneously dispersed in the PI matrix. {yields} The composites showed the low dielectric constant of 50 at 10{sup 6} Hz. {yields} Homogenous dispersion and the amount of ZnO particles contributed to the dielectric properties of composites. -- Abstract: A series of novel ZnO/polyimide composite films with different ZnO contents was prepared through incorporation hexagonal disklike ZnO particles into poly(amic acid) of the pre polymer of the polyimide. The hexagonal disklike ZnO particles with a diameter of 300-500 nm were synthesized from zinc acetate and NaOH in water with citric acid. The prepared zinc oxide-polyimide composites were characterized for their structure, morphology, and thermal behavior employing Fourier transform infrared spectroscopy, scanning electron micrograph, X-ray diffraction and thermal analysis techniques. Thermal analyses show that the ZnO particles were successfully incorporated into the polymer matrix and these ZnO/polymer composites have a good thermal stability. Scanning electron microscopy studies indicate the ZnO particles were uniformly dispersed in the polymer and they remained at the original size (300-500 nm) before immobilization. All composite films with ZnO particle contents from 1 to 5 wt% show good transparency in the visible region and luminescent properties.
Sol–gel synthesis of silver nanocrystals embedded in sodium borosilicate monolithic transparent glass with giant third-order optical nonlinearities
Highlights: • We prepared Ag-doped sodium borosilicate monolithic glass. • The influence of temperature on the SPR absorption peak intensity was studied. • Nonlinear optical properties of the glass were investigated. • A mechanism for the formation of Ag quantum dots glass was proposed. - Abstract: We report the preparation of uniform spherical shape silver nanocrystals doped sodium borosilicate monolithic transparent glass by sol–gel method. The characterization of the resulting Ag nanocrystals was accomplished by using X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectrum. Surface plasma resonance absorption peaks of the silver nanocrystals glass at about 406 nm have been obtained from ultraviolet–visible absorption spectrometer and their intensity is changed with different heat treatment temperatures. We have investigated the nonlinear optical properties of silver quantum dots doped glass using Z-scan technique. Third-order nonlinear optical susceptibility χ{sup (3)} of the glass was estimated to be 1.01 × 10{sup −11} esu. In particular, a mechanism for the formation of Ag quantum dots glass is proposed. This work will significantly promote the obtained material applications in optical devices.
Novel organic–inorganic amorphous photoactive hybrid films with rare earth (Eu{sup 3+}, Tb{sup 3+}) covalently embedded into silicon–oxygen network via sol–gel process
Highlights: • The hybrids are prepared through the hydrolysis and condensation process. • The hybrids are amorphous and heat stabilized. • The hybrids containing Eu{sup 3+} and Tb{sup 3+} show the typical red and green emissions. - Abstract: Novel organic–inorganic hybrid amorphous thin films were synthesized by linking lanthanide (Tb{sup 3+}, Eu{sup 3+}) complexes through 3,4-bis(3-(triethoxysilyl)propylcarbamoyloxy)benzoic acid using sol–gel method. These inorganic–organic hybrids were characterized in detail by Fourier transform infrared spectroscopy, wide angle X-ray diffraction, themogravimetric analysis, scanning electron microscope, and fluorescence spectra. The above research results indicate that the hybrids possess high thermal-stability, amorphous structure features and especially favorable luminescent performances, such as long luminescent decay lifetime, high quantum yield etc.
Ni nanoparticles embedded into cross-linked NiO nanoflakes as enhanced cathode for alkaline batteries
Highlights: • Ni/NiO arrays prepared by hydrothermal synthesis and electrodeposition methods. • Ni/NiO nanoflake arrays show high capacity for alkaline batteries. • Introducing Ni to the NiO nanoflake is favorable for fast electron transfer. - Abstract: Construction of metal/metal oxide composite arrays is highly important for developing advanced electrochemical energy devices. In this work, we report a facile electrodeposition method to embed Ni network into hydrothermal NiO nanoflake arrays. Ni nanoparticles of 10–25 nm are intimately integrated with NiO nanoflakes of 20–30 nm forming cross-linked Ni/NiO composite arrays. The electrochemical potentials of Ni/NiO composite arrays are explored as cathode of alkaline batteries by means of galvanostatic charge/discharge tests and cyclic voltammograms (CV) in KOH solution. Compared with the unmodified NiO nanoflake arrays, the Ni/NiO composite arrays show much better electrochemical properties with higher capacity (100 mAh g{sup −1} vs. 75 mAh g{sup −1} at 2 A g{sup −1}), enhanced cycling life (capacity retention: 96% vs. 82%) after 3800 cycles and improved high-rate capability. The introduction of Ni nanoparticles not only improves the electrical conductivity, but also acts as anchors to fasten the active nanoflakes to achieve long-term cycles.
Braunite phase embedded Y2O3/MnO2-Al2O3-CaO-SiO2 glass ceramics and their properties
Highlights: • Nucleation of synthetic braunite structure (Mn{sub 7}SiO{sub 12}) on sintering of Y{sub 2}O{sub 3}/MnO{sub 2}-CaO-Al{sub 2}O{sub 3}-SiO{sub 2} glasses at 850 °C. • Lossy capacitor behaviour. • Exhibits a critical temperature in 500–600 °C range. • Conduction mechanism shift from Superlinear power law to universal dielectric response law with increase in temperature. - Abstract: Glass series (20-x)Y{sub 2}O{sub 3}-xMnO{sub 2}-20Al{sub 2}O{sub 3}-40SiO{sub 2}-20CaO (x = 5, 10, 15 and 20, mol%) have been synthesized by melt quench technique followed by sintering at 850 °C. The optical band gap of the samples is in wide semiconductor range and increased with MnO{sub 2} content. Photoluminescence study exhibits emission in Mn{sup 2+} d-states. On the other hand, hardness decreases with MnO{sub 2} content except for 10 mol% MnO{sub 2} containing glasses (YM10). The formation of braunite phase in glass ceramics induces capacitive losses. In lower temperature region, the conductivity behaviour of samples follows superlinear power law. In higher temperature region, it follows the universal law of conduction. The dielectric constant for the sintered glasses is constant with respect to temperature, approximately upto 350 °C and 1 MHz frequency. Above 350 °C, the ionic conduction dominates in all the sintered glasses. The anomaly in properties is observed when the ratio of Y{sub 2}O{sub 3}/MnO{sub 2} is 1:1.
In situ monitoring of prestressed concrete using embedded fiber loop ringdown strain sensor
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Evaluation of elastic constants of M23C6 and M7C3 embedded in Fe-Cr-C alloys using in-situ XRD tensile test and self-consistent model
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Free-standing TiO2 nanowire-embedded graphene hybrid membrane for advanced Li/dissolved polysulfide batteries
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Enhancement of the performance of GaP solar cells by embedded In(N)P quantum dots
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Embedded pitch adapters: A high-yield interconnection solution for strip sensors
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Photoelectron yields of scintillation counters with embedded wavelength-shifting fibers read out with silicon photomultipliers
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