Based on the oxidation kinetics of c/Siccomposites at 900o-1200oc in stress-oxidation environment, a non-uniform model of oxidation has been suggested in this paper. combined with fiber notch model, curtin's stre...
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Based on the oxidation kinetics of c/Siccomposites at 900o-1200oc in stress-oxidation environment, a non-uniform model of oxidation has been suggested in this paper. combined with fiber notch model, curtin's strength model and BHE model, the non-uniform model is able to predict the failure time and residual strength of c/Siccomposites accurately. Besides, the initial defects of the model (matrix coating crack and open porosity), the effects of coating were taken into account, and the fiber strength and broken ratio were analyzed. Furthermore, the effects of oxidation time, stress, temperature, Si ccoating thickness and volume fraction of fiber on the failure time and residual strength were discussed, and the predicted results showed a good consistency with the experimental data.
Embedding the functional nanostructures into a lightweight nanocarbon framework is very promising for developing high performance advanced electrodes for rechargeable batteries. Here, to realize workable capacity, cor...
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Embedding the functional nanostructures into a lightweight nanocarbon framework is very promising for developing high performance advanced electrodes for rechargeable batteries. Here, to realize workable capacity, core-shell (FeSe2/c) nanostructures are embedded into carbon nanotube (cNT) framework via a facile wet-chemistry approach accompanied by thermally induced selenization. The cNT framework offers 3D continuous routes for electronic/ionic transfer, while macropores provide adequate space for high mass loading of FeSe2/c. However, the carbon shell not only creates a solid electronic link among cNTs and FeSe2 but also improves the diffusivity of sodium ions into FeSe2, as well as acts as a buffer cushion to accommodate the volume variations. These unique structural features of cNT/FeSe2/c make it an excellent host for sodium storage with a capacity retention of 546 mAh g(-1) even after 100 cycles at 100 mA g(-1). Moreover, areal and volumetriccapacities of 5.06 mAh cm(-2) and 158 mAh cm(-3) are also achieved at high mass loading 16.9 mg cm(-2), respectively. The high performance of multi-benefited engineered structure makes it a potential candidate for secondary ion batteries, while its easy synthesis makes it extendable to further complex structures with other morphologies (such as nanorods, nanowires, etc.) to meet the high energy demands.
N-methylation of amines is one of the most important c-N bond-forming reactions and is widely utilized for the synthesis of numerous agrochemicals, drugs, natural products, and dyes. In this paper, the N-monomethylati...
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N-methylation of amines is one of the most important c-N bond-forming reactions and is widely utilized for the synthesis of numerous agrochemicals, drugs, natural products, and dyes. In this paper, the N-monomethylation of aniline derivatives using Pd/ccatalyst and methanol as the methylation reagent was investigated. The N-monomethylation of various anilines was achieved with high activity and selectivity under relatively mild reaction conditions, and the yield of N-monomethyl anilines was over 90 %. Notably, the commercial, readily available, and inexpensive heterogeneous catalyst, Pd/c, could be easily recovered and reused more than five times with only a slight decrease in activity;gram-scale experiments were also successfully performed.
The aim of this work is to develop high-performance adhesives to join carbon fiber reinforced composites (c/c) for use in aerospace applications;in order to guarantee sound mechanical strength, a low coefficient of th...
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The aim of this work is to develop high-performance adhesives to join carbon fiber reinforced composites (c/c) for use in aerospace applications;in order to guarantee sound mechanical strength, a low coefficient of thermal expansion, and ease of application on large components. Several different adhesive formulations, based on phenolic or cyanate-ester resins (charged with the maximum experimentally feasible amount of carbon-based fillers), are developed and tested. The measurements of the lap shear strength at room temperature of the c/c joined by means of one phenolic and one cyanate ester-based resin demonstrates that these formulations are the most suitable for the given application. A complete characterization, by means of viscosimetry, dilatometry, and thermal gravimetric analysis, coupled with gas analysis by means of mass spectroscopy, confirms that the phenolic-based formulation is the most promising joining material. A nano-indenter is used to obtain its Young modulus and hardness, both inside the joint and as a bulk cured adhesive.
The rapid and accurate detection of H 2 O 2 levels in living cells has important significance in the early-diagnosis of many diseases. In this paper, a non-enzymatic electrochemical biosensor based on Prussian blue (P...
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The rapid and accurate detection of H 2 O 2 levels in living cells has important significance in the early-diagnosis of many diseases. In this paper, a non-enzymatic electrochemical biosensor based on Prussian blue (PB) nanoparticles (NPs) intercalated Ti 3 c 2 nanosheets (PB NPs/Ti 3 c 2 ) was fabricated as a platform for detecting H 2 O 2 . Physico-chemical characterizations revealed the optimized morphology and enlarged surface area of PB NPs/Ti 3 c 2 . When applied to determine H 2 O 2 at the optimal potential, wide linear response in the ranges of 0.6 μM–63.6 μM and 63.6 μM–254 μM, a low limit of detection (0.20 μM), satisfactory stability and anti-interference ability were obtained at PB/Ti 3 c 2 /GcE for the synergistic effect between PB and Ti 3 c 2 on the structure optimization and performance complementation. Moreover, the prepared PB/Ti 3 c 2 showed negligible cytotoxicity to normal fibroblast cells at all tested time points and concentrations, validating its potential application in living cell concerned fields. For proof of concept, the proposed PB/Ti 3 c 2 /GcE realized the real-time and in-situ detection of H 2 O 2 secreted from living HeLa cells. Overall, the biocompatible PB/Ti 3 c 2 sensing interface with a hierarchical structure would be a competitive candidate for H 2 O 2 monitoring in biological samples or cellular investigation.
Shwachman-Diamond syndrome is a rare autosomal recessive disorder (SDS;OMIM #260400) mainly characterized by bone marrow failure, exocrine pancreatic insufficiency, and skeletal defects. The first causative gene is SB...
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Shwachman-Diamond syndrome is a rare autosomal recessive disorder (SDS;OMIM #260400) mainly characterized by bone marrow failure, exocrine pancreatic insufficiency, and skeletal defects. The first causative gene is SBDS, identified in 2003, and patients clinically affected by SDS carry mainly SBDS mutations, and most of them are represented by common pathogenic variants derived from geneticconversion events between SBDS and its pseudogene, SBDSP1. The Italian Registry of SDS collected the index cases who received a clinical SDS diagnosis with the demonstration of SBDS biallelic mutations;one of these is always represented by the [c.258+2T>c], while the second one includes either the [c.183_184delinsTA>cT] or [c.183_184delinsTA>cT+c.258+2T>c] or [c.258+2T>c] in, respectively, 59, 12.5 and 10.83% of cases entered until May 2022. In the 17,67% the SBDS genotype is completed by fourteen different types of rare, private, pathogenic variants and all these alleles were observed once among Italian cases, except for [c.187G>T] and [c.258+533_459+403del] alleles, which were observed in two and four unrelated families, respectively. The first one is present in two families, both originating from Northern Tuscany, while for the second allele, the deletion, three families originate from Sicily and one from Lazio. The presence of the deletion in four families (corresponding to 3.31% of index cases), pushed us to investigate if it could be due to a founder effect, with the same mutation originating from a single ancestral event in all cases. Genotyping the region surrounding the SBDS locus, we defined a common haplotype in the families coming from Sicily, while a completely different one resulted in the family originated from Lazio. This result, identifying the most likely ancestral haplotype associated with the deletion of exon 3, suggested a potential founder effect that might be localized in the provinces of Palermo and Messina, in the middle of the North of Sicily. Our result
As a carbon-neutral alternative technology to the Haber-Bosch process, electrochemical N(2)reduction enables eco-friendly NH(3)synthesis under ambient conditions but requires electrocatalysts to drive the N(2)reductio...
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As a carbon-neutral alternative technology to the Haber-Bosch process, electrochemical N(2)reduction enables eco-friendly NH(3)synthesis under ambient conditions but requires electrocatalysts to drive the N(2)reduction reaction (NRR). Here, P doping is proposed as a valid strategy to greatly increase the NRR activity of the V2O3/c shuttle-like nanostructure. In 0.1 M Na2SO4, the NH(3)yield of original V2O3/c is 12.6 mu g h(-1) mg(cat.)(-1)and a Faraday efficiency (FE) of 6.06% at -0.45 V and -0.25 V vs. reversible hydrogen electrode (RHE), respectively. P-doped V2O3/c (P-V2O3/c), with a mass ratio of P of 6.05%, is capable of achieving a large NH(3)yield of 22.4 mu g h(-1) mg(cat.)(-1)at -0.35 V vs. RHE, and a high FE of 13.78% at -0.25 V vs. RHE. It also shows high electrochemical durability and outstanding selectivity for NH(3)formation. combined with density functional theory calculations, the catalytic mechanism was further explored.
Realizing high capacity at high current densities is one of the challenges for battery electrode materials towards practical applications, especially for metal oxide electrode materials. Designing a specific structure...
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Realizing high capacity at high current densities is one of the challenges for battery electrode materials towards practical applications, especially for metal oxide electrode materials. Designing a specific structure that can alleviate volume expansion and accelerate the diffusion of the ions is an effective way to achieve this goal. Herein, a porous multilayer core-shell structured manganese cobalt oxide/carbon composite (Mnco2O4/c) was obtained by using a simple route that combines the hydrothermal method with calcination. The structure is similar to a Russian doll, which is nested with three to four layers of concentric porous shells. The porous multilayer core-shell structures can relieve volume expansion during discharge/charge and reduce the Li-ion diffusion path. Additionally, it can provide a richer activity site, thereby storing more lithium ions. When used as an anode material, the synthesized Mnco2O4/c showed a high specificcapacity of 978 mAh g(-1)after 800 cycles at a current density of 1 A g(- 1). Even at a high current density of 10 A g(-1), the electrode could still deliver a specificcapacity of 251 mAh g(-1), which makes it more suitable for powering large equipment such as electric vehicles.
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