Four kinds of silicon-metals (Cu, Ni, Sn)-graphite composites for anode active materials of lithium secondary batteries were
prepared by sequential employment of PECVD (Plasma enhance chemical vapor deposition) and RF(Radio-frequency)-magnetron sputtering
method. The silicon-copper-graphite composite showed the highest reversible capacity and cyclability among the silicon-metal
composite graphite samples prepared. The enhanced electrochemical performance of silicon-copper-graphite composite is attributed
to the formation of copper silicide on the surface of graphite.
The copper silicide plays an important role as a buffering layer against volume change of silicon during the intercalation/deintercalation
due to the chemical bonding of silicon and copper, and has lower interfacial impedance than that of other silicon-metal-graphite
composites which may lead to low irreversible capacity. 相似文献
During the solidification of the AZ91D-alloys, the Al8(Mn, Fe)5 phase is generally precipitated in the melt in advance of the precipitation of the primary α-Mg. The basic principle for manufacturing AZ91D-alloy slurries for semi solid forming is to use the Al8(Mn, Fe)5 precipitates as the heterogeneous nucleation sites for primary α-Mg phases. Microscopic analysis for the location of the Al8(Mn, Fe)5 precipitate explains that the Al8(Mn, Fe)5 precipitate is the effective heterogeneous nucleation site for the primary α-Mg phase. It was also observed that increase of the Mn content in the melt and the cooling rate below to the solid/liquid two-phase region resulted in smaller and more globular primary α-Mg due to the increase of heterogeneous nucleation sites. It was found that the average α-Mg diameter grew as a function of t0.278, where t is the holding time at the solid/liquid two-phase region. This would be attributed to the Ostwald type ripening and coalescence between primary α-Mg phases. The cooling rate below to the solid/liquid two-phase region, Mn content in AZ91D alloy, and the holding time and temperature affected on the quality of slurry. 相似文献
Experimental data of high pressure phase behavior from 313.2 to 393.2 K and pressures up to about 14.3 MPa were reported for binary mixture of 2,2,3,3,4,4,4-heptafluorobutyl acrylate (HFBA) and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (HFBMA) in supercritical carbon dioxide. The high pressure experiment was performed by static method using variable-volume view cell apparatus. The CO2+HFBA and CO2+HFBMA systems are correlated with the Peng-Robinson equation of state using a van der Waals one-fluid mixing rule. The CO2+HFBA and CO2+HFBMA systems exhibit type-I phase behavior with continuous critical mixture curves. 相似文献
The objective of this study was to investigate the influence of zinc on the sporulation and viability of Clostridium sporogenes and on the growth of other bacteria. When 0.5% ZnCl2 was added to a sporulation medium, it completely inhibited C. sporogenes (PA 3679) sporulation for up to 3 weeks. At concentrations of 0.5% and 1.0%, ZnCl2 not only completely inactivated the vegetative cell viability (>7.0 Log reduction) but also significantly reduced the spore viability (<2.1 Log reduction) of C. sporogenes. Taken together, it was concluded that zinc blocks C. sporogenes sporulation by damaging (or killing) vegetative cells and probably by interfering with the biosynthesis of spore components. In addition to the inhibitory effect on the sporulation and viability of C. sporogenes, ZnCl2 was found to have a broad antimicrobial spectrum against all Gram‐positive and Gram‐negative spoilage and pathogenic bacteria tested. The minimal inhibitory concentration for inhibiting the bacteria ranged between 3.7 and 7.4 mm . Therefore, we expect that this compound or a combination thereof has a potential as a surface‐cleaning agent or disinfectant. 相似文献
In general, size, shape and dispersion of phases in alloys significantly affect mechanical properties. In this study, the mechanical properties of Mo-Si-B alloys were experimentally investigated with regards to the refinement of intermetallic compound. To confirm the size effect of the intermetallic compound phases on mechanical properties, two differently sized intermetallic compound powders consisting Mo5SiB2 and Mo3Si were fabricated by mechano-chemical process and high-energy ball milling. A modified powder metallurgy method was used with core-shell intermetallic powders where the intermetallic compound particles were the core and nano-sized Mo particles which formed by the hydrogen reduction of Mo oxide were the shells, leading to the microstructures with uniformly distributed intermetallic compound phases within a continuous α-Mo matrix phase. Vickers hardness and fracture toughness were measured to examine the mechanical properties of sintered bodies. Vickers hardness was 472 Hv for the fine intermetallic compound powder and 415 Hv for the coarse intermetallic compound powder. The fracture toughness was 12.4 MPa·√m for the fine IMC powders and 13.5 MPa·√m for the coarse intermetallic compound powder. 相似文献
The purpose of this paper is to present the first step in developing the zone method for inhomogeneous media that has never been published in the literature. It was derived and formulated using matrix relations for a plane layer system enclosing a non-isothermal and inhomogeneous gray and absorbing, emitting and isotropically scattering media. The media are enclosed by two infinite parallel plates that are opaque, diffuse, and gray, but the formulations allow transparent plate. The formulations recover homogeneous cases and satisfy the conservation relations. The accuracy of the zone method is verified by comparing with available exact solutions. Through the accuracy check, validity of the zone method is also shown. Thus, formulations presented can be used to test the accuracy of the works by others for the problem in the study that has many applications in engineering and science.