RESUMO
The pouring time interval is the decisive factor of dual-liquid casting for bimetallic productions. Traditionally, the pouring time interval is fully determined by the operator's experience and on-site observation. Thus, the quality of bimetallic castings is unstable. In this work, the pouring time interval of dual-liquid casting for producing low alloy steel/high chromium cast iron (LAS/HCCI) bimetallic hammerheads is optimized via theoretical simulation and experimental verification. The relevancies of interfacial width and bonding strength to pouring time interval are, respectively, established. The results of bonding stress and interfacial microstructure indicate that 40 s is the optimum pouring time interval. The effects of interfacial protective agent on interfacial strength-toughness are also investigated. The addition of the interfacial protective agent yields an increase of 41.5% in interfacial bonding strength and 15.6% in toughness. The optimum dual-liquid casting process is used to produce LAS/HCCI bimetallic hammerheads. Samples cut from these hammerheads show excellent strength-toughness (1188 Mpa for bonding strength and 17 J/cm2 for toughness). The findings could be a reference for dual-liquid casting technology. They are also helpful for understanding the formation theory of the bimetal interface.
RESUMO
Density functional theory was employed to investigate the (111), (200), (210), (211) and (220) surfaces of CoS2. The surface energies were calculated with a sulfur environment using first-principle-based thermodynamics. It is founded that surfaces with metal atoms at their outermost layer have higher energy. The stoichiometric (220) surface terminated by two layer of sulfur atoms is most stable under the sulfur-rich condition, while the non-stoichiometric (211) surface terminated by a layer of Co atoms has the lower energy under the sulfur-poor environment. The electric structure results show that the front valence electrons of (200) surface are active, indicating that there may be some active sites on this face. There is an energy gap between the stoichiometric (220) and (211), which has low Fermi energy, indicating that their electronic structures are dynamically stable. Spin-polarized bands are calculated on the stoichiometric surfaces, and these two (200) and (210) surfaces are predicted to be noticeably spin-polarized. The Bravais-Friedel-Donnay-Harker (BFDH) method is adopted to predict crystal growth habit. The results show that the most important crystal planes for the CoS2 crystal growth are (111) and (200) planes, and the macroscopic morphology of CoS2 crystal may be spherical, cubic, octahedral, prismatic or plate-shaped, which have been verified by experiments.
RESUMO
The F-box family is one of the largest gene families in plants that regulate diverse life processes, including salt responses. However, the knowledge of the soybean F-box genes and their roles in salt tolerance remains limited. Here, we conducted a genome-wide survey of the soybean F-box family, and their expression analysis in response to salinity via in silico analysis of online RNA-sequencing (RNA-seq) data and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) to predict their potential functions. A total of 725 potential F-box proteins encoded by 509 genes were identified and classified into 9 subfamilies. The gene structures, conserved domains and chromosomal distributions were characterized. There are 76 pairs of duplicate genes identified, including genome-wide segmental and tandem duplication events, which lead to the expansion of the number of F-box genes. The in silico expression analysis showed that these genes would be involved in diverse developmental functions and play an important role in salt response. Our qRT-PCR analysis confirmed 12 salt-responding F-box genes. Overall, our results provide useful information on soybean F-box genes, especially their potential roles in salt tolerance.
