Stretchable energy storage devices,maintaining the capability of steady operation under large mechanical strain,have become increasing more important with the development of stretchable electronic *** supercapacitors(...
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Stretchable energy storage devices,maintaining the capability of steady operation under large mechanical strain,have become increasing more important with the development of stretchable electronic *** supercapacitors(SSCs),with high power density,modest energy density,and superior mechanical properties are regarded as one of the most promising power supplies to stretchable electronic *** polymers,such as polyaniline(PANI),polypyrrole(PPy),polythiophene(PTh)and poly(3,4-ehtylenedioxythiophene)(PEDOT),are among the well-studied electroactive materials for the construction of SSCs because of their high specific theoretical capacity,excellent electrochemical activity,light weight,and high *** effort has been devoted to developing stretchable,conductive polymer-based SSCs with different device structures,such as sandwich-type and fiber-shaped type *** review summarizes the material and structural design for con ductive polymer-based SSCs and discusses the challenge and importa nt di recti ons in this emergi ng field.
This paper demonstrates the generation of DSC thermograms from TREF chromatograms. The reverse is clearly possible, and shows that compositional distribution information is obtainable from DSC using solution crystalli...
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This paper demonstrates the generation of DSC thermograms from TREF chromatograms. The reverse is clearly possible, and shows that compositional distribution information is obtainable from DSC using solution crystallized material. However, TREF is essential, at least initially, in providing fractions for calibration curves.
A method for systematic evaluation of the Lennard-Jones parameters for polycyclic aromatic hydrocarbon (PAH) compounds is presented, in which correlations for these parameters are derived using a group contribution te...
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A method for systematic evaluation of the Lennard-Jones parameters for polycyclic aromatic hydrocarbon (PAH) compounds is presented, in which correlations for these parameters are derived using a group contribution technique for critical temperatures and pressures and the Tee-Gotoh-Stewart correlations of corresponding states. The Lennard-Jones self-collision diameters and well depths of 29 PAHs were estimated using this approach and are shown to correlate with the molecular weights of aromatics. The gaseous binary diffusion coefficients of aromatics in common gases were calculated with Chapman-Enskog equation using the estimated Lennard-Jones parameters and were found to compare well with the available experimental data and the predictions of one of the most reliable empirical approximations. The effect of ordinary diffusion of PAH species on their predicted concentration profiles in a 20-torr laminar premixed acetylene flame is demonstrated computationally.
A commercial Co-Mo/Al 2 O 3 HDS catalyst displayed catalytic activity towards the coking of anthracene. This is related to its hydrogenation/dehy As with the Al 2 O 3 support, little or no coking activity was displaye...
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A commercial Co-Mo/Al 2 O 3 HDS catalyst displayed catalytic activity towards the coking of anthracene. This is related to its hydrogenation/dehy As with the Al 2 O 3 support, little or no coking activity was displayed by a carbon black composite. Following the addition of Co and Mo to the c
The strategy of sequentially spin-coating a perovskite film from the perovskite precursor and an electron transporting layer of [6,6]-phenyl-C71-butyric acid methyl ester （PC71BM） is developed to simplify the fabric...
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The strategy of sequentially spin-coating a perovskite film from the perovskite precursor and an electron transporting layer of [6,6]-phenyl-C71-butyric acid methyl ester （PC71BM） is developed to simplify the fabrication procedure of perovskite solar cells. X-ray diffraction and scanning electron microscopy indicate that PCTIBM film on perovskite layer can retard the evaporation of dimethyl sulfoxide （DMSO） efficiently, thus prolonging the transformation of intermediate phase to perovskite crystals, leading to a high quality perovskite thin film. The solar cells with the structure of indium tin oxides （ITO）/poly（3,4-ethylenedioxythiophene）：poly（styrenesulfonate） （PEDOT：PSS）/CH3NH3PbI3/PC71BM/bathocuproine （BCP）/Ag made from this simplified method exhibit a higher efficiency （12.68%） than those from the conventional one-step method （9.49%）.
This paper reports on the application of solid-state CPMAS C-13 NMR and flash pyrolysis-GC-MS for characterization of the macromolecular network of a Montana subbituminous coal and its residues from temperature-progra...
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This paper reports on the application of solid-state CPMAS C-13 NMR and flash pyrolysis-GC-MS for characterization of the macromolecular network of a Montana subbituminous coal and its residues from temperature-programmed and non-programmed liquefaction (TPL and N-PL) at final temperatures ranging from 300 to 425-degrees-C in H-donor and non-donor solvents. The combined use of C-13 NMR and Py-GC-MS revealed that this coal contains significant quantities of oxygen-bearing structures, corresponding to about 18 O-bound C per 100 C atoms and one 0-bound C per every five to six aromatic C's. The oxygen-bearing components in the coal include catechol-like structures, which seem to disappear from the liquefaction residues above 300-degrees-C;carboxyl groups, which almost disappear after 350-degrees-C;and phenolic structures, which are most important in the original coal but diminish in concentration with increasing temperature. These results point to the progressive loss of oxygen functional groups and aliphatic-rich species from the macromolecular network of the coal during programmed heat-up under TPL conditions. The higher conversions in TPL runs in H-donor tetralin (relative to the conventional N-PL runs) suggest that the removal of carboxylic and catechol groups from the coal and the capping of the reactive sites by H-transfer from H-donors at low temperatures (less-than-or-equal-to 350-degrees-C) have contributed to minimizing the retrogressive crosslinking at higher temperatures. Quantitative calculation of NMR data and mathematical correlation were also attempted in this work. For 24 liquefaction residues derived under significantly different conditions, linear correlations between C-distribution and reaction temperature (greater-than-or-equal-to 300-degrees-C) have been found, which can be expressed by a simple equation, C(i) = alphaf(i) + betaT, where f(i) and C(i) represent content of aromatic, aliphatic, or oxygen-bound carbons in the original coal and residue,
The effects of quantity of mobile phase, viscosity of mobile phase, and network reactivity were evaluated on the liquefaction conversion of four coals. Reactions were carried out 275-degrees-C for 10 and 30 minutes, a...
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The effects of quantity of mobile phase, viscosity of mobile phase, and network reactivity were evaluated on the liquefaction conversion of four coals. Reactions were carried out 275-degrees-C for 10 and 30 minutes, and in a temperature-staged configuration for 30 minutes each at 275 and 425-degrees-C. Coals were impregnated with a sulfided ammonium molybdate catalyst. If all other factors were held reasonably comparable, it was found that a coal having lower viscosity mobile phase produced higher conversions at 275-degrees-C than a similar coal having a more viscous mobile phase. This effect is attributed to easier transport of the mobile phase from the interior of a coal particle to the catalyst on the particle's surface. For coals having comparable viscosities of mobile phase and comparable network reactivities, the coal having the greater quantity of mobile phase produced higher conversions. When network reactivity was the principal difference, the coal having the less reactive network resulted in lower conversion. Thus for good liquefaction conversions at relatively mild conditions, a cold having a large amount of fluid (low viscosity) mobile phase and a reactive network is desirable. These differences among coals are much less apparent in temperature-staged liquefaction;the much severe reaction conditions appear to overwhelm the subtle differences of mobile phase and network properties.
The onset of sooting in laminar premixed flames was examined computationally. Three series of atmospheric fuel-oxygen-nitrogen flames of ethane, ethylene, and acetylene were simulated using a detailed chemical kinetic...
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The onset of sooting in laminar premixed flames was examined computationally. Three series of atmospheric fuel-oxygen-nitrogen flames of ethane, ethylene, and acetylene were simulated using a detailed chemical kinetic model of soot particle nucleation and growth. It was found that the critical equivalence ratios for soot appearance, both the absolute values and temperature dependencies, can be predicted fairly close to the experimental observations, even when no reactions for the oxidation of aromatics by hydroxyl are included in the mechanism. The analysis of the computational results strongly suggests that the appearance of soot is controlled by two factors, concentration of acetylene and growth of polycyclic aromatics, and the latter is limited by the rise in flame temperature towards the end of the main reaction zone. The present results and conclusions are in agreement with the principal findings of previous modeling studies.
The main objective of this paper is to explore the potentials and possible ways to develop high-value chemicals and materials from coals and coal liquids. Recently it has become clear that more extensive use of fossil...
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The main objective of this paper is to explore the potentials and possible ways to develop high-value chemicals and materials from coals and coal liquids. Recently it has become clear that more extensive use of fossil fuels, especially coal, may be constrained not only by economics, but also by environmental considerations such as SO(x) and NO(x) emissions and global warming. Therefore, new concepts are required, and significant advances are essential for the effective utilization of coals in the next century. Both from economic and environmental viewpoints, developing high-value chemicals and materials from coals and coal liquids should lead to more efficient and environmentally safe utilization of the valuable carbonaceous resources. It is important to explore the routes and methods for developing specialty chemicals, which are difficult to obtain or not readily available from petroleum, advanced polymeric engineeringmaterials, and high-performance carbon materials. Recent years have seen significant progress in the development and application of new, industrially important aromatic engineering plastics, thermoplastic materials, liquid crystalline polymers, and membrane materials. Many of the monomers for these materials can be prepared from one- to four-ring aromatics such as alkylated benzenes, naphthalene, biphenyl, anthracene, phenanthrene, pyrene, phenol, and carbazole. Especially important are 2,6-dialkylnaphthalenes, 4,4'-dialkylbiphenyls, and 1,4-dialkylbenzenes. The large-volume application of aromatic high-performance polymers depends on lowering their cost, which in turn is largely determined by the cost of the aromatic monomers. By developing the critical aromatic chemicals from coals, coal-to-chemicals research could contribute significantly to high-technology development. Potential large-volume markets for materials from coal can be stimulated by developing high-performance carbon materials such as carbon fibers and graphites, and by developing ways
Bone tissue engineering is an exciting approach to directly repair bone defects or engineer bone tissue for *** play a pivotal role in providing a template and extracellular environment to support regenerative cells a...
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Bone tissue engineering is an exciting approach to directly repair bone defects or engineer bone tissue for *** play a pivotal role in providing a template and extracellular environment to support regenerative cells and promote tissue regeneration. A variety of signaling cues have been identified to regulate cellular activity, tissue development, and the healing process. Numerous studies and trials have shown the promise of tissue engineering, but successful translations of bone tissue engineering research into clinical applications have been limited, due in part to a lack of optimal delivery systems for these signals. Biomedical engineers are therefore highly motivated to develop biomimetic drug delivery systems, which benefit from mimicking signaling molecule release or presentation by the native extracellular matrix during development or the natural healing process. Engineered biomimetic drug delivery systems aim to provide control over the location, timing, and release kinetics of the signal molecules according to the drug's physiochemical properties and specific biological mechanisms. This article reviews biomimetic strategies in signaling delivery for bone tissue engineering, with a focus on delivery systems rather than specific molecules. Both fundamental considerations and specific design strategies are discussed with examples of recent research progress, demonstrating the significance and potential of biomimetic delivery systems for bone tissue engineering.
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