Characterisation of dispersions within annealed HVOLF thermally sprayed AlSnCu coatings

High velocity oxy-liquid fuel (HVOLF) AlSnCu coatings are characterised following annealing for up to 5 hours at 300°C. A combination of statistical analysis of BSE images and TEM observations demonstrate the decrease in the number of sub-micron and nanoscale Sn particles with annealing, commensurate with a decrease in the coating microhardness. TEM evidence further suggests the coarsening of nanoscale Sn through a mechanism of a liquid phase migration within the Al matrix. EELS and EFTEM additionally allow the identification of the precipitation of theta'

Effect of preparation method of palygorskite-supported Fe and Ni catalysts on catalytic cracking of biomass tar

In this study, the effect of catalyst preparation and additive precursors on the catalytic decomposition of biomass using palygorskite-supported Fe and Ni catalysts was investigated. The catalysts were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It is concluded that the most active additive precursor was Fe(NO3)3·9H2O. As for the catalyst preparation method, co-precipitation had superiority over incipient wetness impregnation at low Fe loadings

Dimer-monomer model on the Sierpinski gasket

We present the numbers of dimer-monomers on the Sierpinski gasket $SG_d(n)$ at stage $n$ with dimension $d$ equal to two, three and four, and determine the asymptotic behaviors. The corresponding results on the generalized Sierpinski gasket $SG_{d,b}(n)$ with $d=2$ and $b=3,4$ are obtained.Comment: 30 pages, 10 figures, 10 table

Discovery of a 552 Hz burst oscillation in the low-mass X-ray binary EXO 0748-676

We report the detection of pulsations at 552 Hz in the rising phase of two type-I (thermonuclear) X-ray bursts observed from the accreting neutron star EXO 0748-676 in 2007 January and December, by the Rossi X-ray Timing Explorer. The fractional amplitude was 15% (rms). The dynamic power density spectrum for each burst revealed an increase in frequency of approx. 1-2 Hz while the oscillation was present. The frequency drift, the high significance of the detections and the almost identical signal frequencies measured in two bursts separated by 11 months, confirms this signal as a burst oscillation similar to those found in 13 other sources to date. We thus conclude that the spin frequency in EXO 0748-676 is within a few Hz of 552 Hz, rather than 45 Hz as was suggested from an earlier signal detection by Villarreal & Strohmayer (2004). Consequently, Doppler broadening must significantly affect spectral features arising from the neutron star surface, so that the narrow absorption features previously reported from an XMM-Newton spectrum could not have arisen there. The origin of both the previously reported 45 Hz oscillation and the X-ray absorption lines is now uncertain.Comment: 5 pages, 2 figures, accepted for Astrophysical Journal Letters. Minor changes following referees repor

The role of climate in human mitochondrial DNA evolution: A reappraisal

AbstractPrevious studies have proposed that selection has been involved in the differentiation of human mitochondrial DNA (mtDNA) and climate was the main driving force. This viewpoint, however, gets no support from the subsequent studies and remains controversial thus far. To clarify this issue, a total of 237 complete mtDNA sequences belonging to autochthonous lineages from South Asia, Oceania, and East Asia were collected to seek for the imprint of selection. Based on nonsynonymous (N) and synonymous (S) substitutions analysis, our results confirmed that purifying selection was the predominant force during the evolution of human mtDNA. However, no significant and extensive difference was detected among these three regions, which did not support the climate adaptation hypothesis but preferred random genetic drift to be the main factor in shaping the current landscape of human mtDNA, at least those from Asian and Oceanian regions

Implementing Path of Zhengzhou University\u27s Establishment of Football Academy

Under the new policy background of the 2020 Opinions on Deepening the Integration of Sports and Education and Promoting the Healthy Development of Adolescents , as the highest educational institution in China, higher education institutions should shoulder the responsibility of cultivating high-quality talents to meet social needs. As the highest-quality higher education institution in Henan Province, Zhengzhou University\u27s innovation and exploration of teaching methods and talent training models under the background of the integration of sports and education will play a leading role in the development of higher education in Henan Province. Through combing and analyzing the existing policy documents, firstly, explore the reasons, significance, and social background of the construction of the football academy; secondly, analyze the theoretical basis for the construction of the football academy in the context of relevant policies, and analyze the demand for talent training required by the policy. It was combining with the construction situation of my country’s football academy at this stage, implementing the specific requirements of the integration strategy of sports and education, establishing the guiding ideology of “diversified integration” after establishing the academy from the three levels of discipline establishment, talent training, and talent transfer. Investigate the needs of the talent market at the stage, determine the direction of talent training, and discuss how to set up specific majors for domestic enrollment after the establishment of the college. Based on this, it proposes the professional setting direction and specific curriculum arrangement and assessment methods for talent training from five aspects: education and teaching, sports competitions, sports medicine, sports media, economics, and management. Finally, it discusses the difficulties faced by students, teachers, and employment development after graduation in the process of football academy construction and how to use existing resources and related policy support to solve the difficulties. As an innovative way of running a school, the Football Academy provides new opportunities for the reform and innovation of sports talent cultivation. In the torrent of sports and education integration reform, make full use of existing resources, integrate and mobilize various high-quality resources in the region, and finally transform them into the winning resources for the new development of our school\u27s sports discipline in this innovative school-running method. After the football academy is established, it will become a link between campus football and professional football in the province, and a breeding base for national high-quality football industry talents. It will also provide a strong impetus for the development of football in my country