In this study, pyrolysis of low-density polyethylene (LDPE) and LDPE with aluminum (c/LDPE) wastes was carried out with different heating rates (5, 10, 20 degrees c/min) at different temperatures (400, 600, 800 degree...
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In this study, pyrolysis of low-density polyethylene (LDPE) and LDPE with aluminum (c/LDPE) wastes was carried out with different heating rates (5, 10, 20 degrees c/min) at different temperatures (400, 600, 800 degrees c). Product yields of LDPE and c/LDPE wastes were compared, and optimum liquid products were analyzed to utilize as commercial waxes for future use. The properties of pyrolyzed wastes was investigated with proximate, elemental analysis, and TGA. The as-produced liquid from pyrolysis of wastes was characterized by different characteristic tools, such as elemental analyses, Gc-MS analyses, 1H-NMR tests, FT-IR spectra, the density, melting point, and carbon residue to compare commercial waxes. As a result of pyrolysis, the highest liquid product yield was achieved at 800 degrees c with 5 degrees c/min heating rate (85.87%) and at 600 degrees c with 5 degrees c/min heating rate (71.3%) for LDPE and c/LDPE, respectively. The results indicated that the derived liquid products are similar to commercial heavy wax.
Manganese oxide (MnO) is prospective as anode material for lithium-ion batteries (LIBs) due to its low insertion voltage and high reversible capacity. Here, urchin-like MnO microspheres with carbon coating (u-MnO/c) a...
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Manganese oxide (MnO) is prospective as anode material for lithium-ion batteries (LIBs) due to its low insertion voltage and high reversible capacity. Here, urchin-like MnO microspheres with carbon coating (u-MnO/c) are synthesized through hydrothermal method, and its lithium storage performance is investigated. The unique urchin-like structures of u-MnO/c endow it high surface area which provides sufficient contact with electrolyte. The carbon coating can effectively suffer volume change of u-MnO during charge/discharge process. Meanwhile, the carbon coating can effectively improve the conductivity of u-MnO-based anode. Due to the above features, u-MnO/c delivers high initial capacity of 845 mAh g(-1), and an obvious activation process is observed at the beginning of the cycles thanks to the abundant invasion of the electrolyte into u-MnO/c. The large capacity of 723 mAh g(-1) can still be achieved after 80 cycles. This work provides a promising guide for designing high-performance LIBs electrode materials.
Iron single atom catalysts (FeN4) hosted in the micropores of N-doped carbons offer excellent performance for the oxygen reduction reaction (ORR). Achieving a high density of FeN4 sites accessible for ORR has proved c...
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Iron single atom catalysts (FeN4) hosted in the micropores of N-doped carbons offer excellent performance for the oxygen reduction reaction (ORR). Achieving a high density of FeN4 sites accessible for ORR has proved challenging to date. Herein, a simple surface Nacl-assisted method towards microporous N-doped carbon electrocatalysts with an abundance of catalytically accessible FeN4 sites is reported. Powder mixtures of microporous zeolitic imidazolate framework-8 and Nacl are first heated to 1000 degrees c in N-2, with the melting of Nacl above 800 degrees ccreating a highly porous N-doped carbon product (Nc-Nacl). Ferric (Fe3+) ions are then adsorbed onto Nc-Nacl, with a second pyrolysis stage at 900 degrees c in N-2 yielding a porous Fe/Nc-Nacl electrocatalyst (Brunauer-Emmett-Teller surface area, 1911 m(2) g(-1)) with an excellent dispersion and high density of accessible surface FeN4 sites (26.3 x 10(19) sites g(-1)). The Fe/Nc-Nacl electrocatalyst exhibits outstanding ORR performance with a high half-wave potential of 0.832 V (vs reversible hydrogen electrode) in 0.1 m HclO4. When used as the ORR cathode catalyst in a 1.0 bar H-2-O-2 fuel cell, Fe/Nc-Nacl offers a high peak power density of 0.89 W cm(-2), ranking it as one of the most active M-N-c materials reported to date.
Exponential growth in the field of covalent-organic frameworks (cOFs) is emanating from the direct correlation between designing principles and desired properties. The comparison of catalytic activity between single-p...
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Exponential growth in the field of covalent-organic frameworks (cOFs) is emanating from the direct correlation between designing principles and desired properties. The comparison of catalytic activity between single-pore and dual-pore cOFs is of importance to establish structure-function relationship. Herein, the synthesis of imine-linked dual-pore [(BPyDc)](x)(%)-ETTA cOFs (x = 0%, 25%, 50%, 75%, 100%) with controllable bipyridine content is fulfilled by three-component condensation of 4,4 ',4 '',4 '''-(ethene-1,1,2,2-tetrayl)tetraaniline (ETTA), 4,4 '-biphenyldialdehyde, and 2,2 '-bipyridyl-5,5 '-dialdehyde in different stoichiometric ratio. The strong coordination of bipyridine moieties of [(BPyDc)](x)(%)-ETTA cOFs with palladium imparts efficient catalytic active sites for selective functionalization of sp(2)c-H bond to c-X (X = Br, cl) or c-O bonds in good yield. To broaden the scope of regioselective c-H functionalization, a wide range of electronically and sterically substituted substrates under optimized catalyticcondition are investigated. A comparison of the catalytic activity of palladium decorated dual-pore frameworks with single-pore imine-linked Pd(II) @ Py-2,2 '-BPyDc framework is undertaken. The finding of this work provides a sporadic example of chelation-assisted c-H functionalization and disclosed an in-depth comparison of the relationship between superior catalytic activity and core properties of rationally designed imine linked frameworks.
Three Mo-Ti-Si-B alloys with compositions of 50Mo-20Ti-20Si-10B, 40Mo-30Ti-20Si-10B and 30Mo-40Ti-20Si-10B (at.%) were designed and prepared by arc-melting. Microstructure evolution at 1600 degrees c and oxidation mec...
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Three Mo-Ti-Si-B alloys with compositions of 50Mo-20Ti-20Si-10B, 40Mo-30Ti-20Si-10B and 30Mo-40Ti-20Si-10B (at.%) were designed and prepared by arc-melting. Microstructure evolution at 1600 degrees c and oxidation mechanism at 800 degrees c of these alloys were analyzed. 50Mo-20Ti-20Si-10B suffered from pesting because of a large volume fraction of Mo3Si, which produced porous products with severe volume expansion. Both 40Mo-30Ti-20Si-10B and 30Mo-40Ti-20Si-10B have better oxidation resistance. It can be inferred that during long-term oxidation, interactions between constituent phases contributed to the overall oxidation resistance of the alloys.
A facile one-step solvothermal method to synthesize SnS/SnO2/c nanocluster particles has been reported. The nanocluster particles are derived from SnS2/ccomposite materials by adjusting pyrolysis temperature at 600 d...
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A facile one-step solvothermal method to synthesize SnS/SnO2/c nanocluster particles has been reported. The nanocluster particles are derived from SnS2/ccomposite materials by adjusting pyrolysis temperature at 600 degrees c within 6 h under N-2 atmosphere. When assessed as anode materials for lithium-ion batteries (LIBs), SnS/SnO2/c nanocluster particles can deliver a high initial discharge capacity of 1978 mA h g(-1) and maintain high discharge capacity of 638 mA h g(-1) after 50 cycles at a current density of 100 mA g(-1), which is better than other pyrolysis products derived from SnS2/c materials. This work indicates that SnS/SnO2/c nanocluster particles may be a promising anode material for lithium-ion batteries and provides a simple method to construct ternary composite materials for energy storage.
The blending system of chitooligosaccharide (cOS) and polyethyleneimine (PEI) was studied as a drug carrier for tumor treatment. Nanoparticles cOS/PEI-PolyI:c-OVA-x (cP-P-O-x) (x=1, 2, 3) were prepared by electrostati...
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The blending system of chitooligosaccharide (cOS) and polyethyleneimine (PEI) was studied as a drug carrier for tumor treatment. Nanoparticles cOS/PEI-PolyI:c-OVA-x (cP-P-O-x) (x=1, 2, 3) were prepared by electrostatic self-assembly of cOS and PEI with the immune enhancing drug PolyI:c and the mimic antigen ovalbumin (OVA) using different feeding methods. The results showed that the nanoparticle solution could be stable only when the concentration of the added PEI was above 5.0% w/w. PolyI:ccould be coated well and protected from nuclease degradation. The OVA encapsulation efficiency was above 75%. The results of cell viability experiments showed that the blend of cOS and PEI had low cytotoxicity. The cP-P-O-1 had a suitable particle size, which was easy to be absorbed and expressed by cells. The results of in vitro immunization showed that due to the addition of PolyI:c, whether OVA was loaded on the inside or on the surface, nanoparticles significantly promoted the secretion of cytokines mouse tumor necrosis factor alpha (TNF-alpha) and mouse interferon-gamma (IFN-gamma). The feeding method mainly had a greater impact on the morphology and size of the nanoparticles, and had little effect on solution stability, OVA encapsulation efficiency, binding ability with PolyI:c, resistance to nuclease degradation and immune performance. cP-P-O-x prepared by the blend system of cOS and PEI will be a potential candidate for tumor treatment.
Transpiration cooling system in hypersonic vehicles still remains a challenge due to the limitations of observing permeability and microstructure evolution of porous medium filled with coolant. To tackle this problem,...
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Transpiration cooling system in hypersonic vehicles still remains a challenge due to the limitations of observing permeability and microstructure evolution of porous medium filled with coolant. To tackle this problem, a novel compression-permeation device is designed with high-resolution X-ray tomography system, and then an investigation on permeability evolution mechanism of a c/Sic porous ceramic under pressure is performed using insitu X-ray imaging and the compression-permeation device. The experimental results indicate that the pore-space fluid flow is displayed in terms of three-dimensional streamlines, making the permeability mechanism clear. Meanwhile the porosity along the thickness of ceramic under pressure has been obtained by synchrotron tomography testing, and it is also verified that the porosity of c/Sicceramic fabricated in our research group is basically uniform (>95.4%) along the thickness. Furthermore, we have found the evolution rule for permeability of porous ceramic with water, which depends on the variation of its microstructure under different loads.
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