Key Engineering Materials Vol. 815

Abstract: In this paper, carbon coated spherical Mn₃O₄ was prepared by decomposition of spherical MnCO₃ and sucrose. The results of XRD and SEM showed that Mn₃O₄/C composites are sphere-like with good crystallinity, and its diameter is about 1um. It could deliver a reversible charge capacity of 848.7 mA h g^-1 at the current density of 162.3 mA g^-1, and the specific discharge capacity is still have 441 mA h g^-1 at a high current density of 649.4 mA g^-1 exhabiting good rate performance. The excellent performance of the spherical Mn₃O₄/C composites could be attributed to its unique architecture which provides fast lithium ion and electron transportation as well as accommodates the large volume change of transition metal oxides during conversion reactions.

Abstract: In this work, we report rapid hydrothermal growth of ZnO nanorods on a magnetron sputtered thick ZnO seed layer. The ZnO seed layer on the glass substrarte is monocrystalline and formed by 600 °C annealing for 1 hour after magnetic sputtering. The morphology of the ZnO grain in the ZnO seed layer plays a critical role in the growing of the ZnO nanorods, and the slant ZnO grain results in the slant ZnO nanorod and connected ZnO nonrods. It is found that the average growth of the ZnO nanorods is ~75 nm/minute. The rapid grow rate may be owing to the monocrystallie and the pure water solution of the growth solution.

Abstract: A thermodynamic evaluation of the binary LaCl₃-CaCl₂ system was carried out by using CALPHAD method. The Modified Quasihelical Model was defined in order to describe the Gibbs energies of the liquid phases, and the model parameters were optimized from the experimental thermodynamic and phase diagram data. The phase diagram and the enthalpy of mixing of LaCl₃-CaCl₂ liquid were calculated. For LaCl₃-CaCl₂, a calculated eutectic point was observed at 924.82 K, 34.8 mol. % LaCl₃. The calculated enthalpy of mixing is exothermic, the minimum was found at approximately 30 mol. % LaCl₃. The thermodynamic properties and the phase diagram calculated from the optimized parameters agree well with the experimental data.

Abstract: Considering the S-vacancy defect in single-layer MoS₂, the metal doped including Fe-, Co-, Cu-, Zn-, doped specimens in MoS₂ single-layer and their effect of the adsorption and diffusion of Li on the MoS₂ single-layer were investigated by Density Functional Theory (DFT). Under Mo-rich condition, the Fe-, Co-, Cu-, Zn-doped specimens by substitution of S atom have smaller formation energy than those under S-rich condition. For doped MoS₂ single-layer, lithium donates electron to doped specimens, making the band level of the doped specimens downward into the valence band and the Fermi energy level further upward. The Li ion has positive charge, the ion adsorptive property was enhanced because of strong coulomb interaction. These are confirmed by the large adsorption energies (-1.11 ~ -0.44 eV). The diffusion energy barriers except for the path closest doped specimens by substitution of S atom are ~ 0.25, which are similar to that of pristine one. Above all, the metal doped by substitution of S atom MoS₂ single-layer are promising anode materials of LIBs.

Abstract: This paper proposes a cache replacement algorithm based on STT-MRAM magnetic memory, which aims to make the material system based on STT-MRAM magnetic memory better used. The algorithm replaces the data blocks in the cache by considering the position of the STT-MRAM magnetic memory head and the hardware characteristics of the STT-MRAM magnetic memory. This method will be different from the traditional magnetic memory-based common cache replacement algorithm. Traditional replacement algorithms are generally designed with only the algorithm to improve the cache, and the hardware characteristics of the storage device are ignored. This method can improve the material characteristics of the STT-MRAM magnetic memory by improving the cache life and efficiency.

Abstract: A new generation of high performance polysiloxane white coating has been peeling off a large area after being applied on a special ship for 10 years, which has a great impact on the appearance of the hull. Based on the curing mechanism and physicochemical characteristics of acrylic polysiloxane coating, the reason of existing coating stripping was analyzed. Through a small range test, We can explore the method of coating repair.

Abstract: The development of electronic science technology makes electromag-netic radiation problems increasingly severe. High-performance absorbing and shielding electromagnetic wave materials with light weight are researched and developed as one of effectiveness methods to restrain electromagnetic radiation and prevent information leakage. The absorbing properties of aluminium foams coating absorbing paint were studied and tested by making use of RCS in “the reflectivity testing measurement of radar absorbing material” of GJB 2038-94 in this work. The effect of absorbent species and metal base structure on absorbing properties of materials was discussed. The results indicate that the absorbing properties of materials coating magnetic dielectric absorbing paint are better than others, and that of the sample CFe are best in 12.0—18.0GHz, while that of the sample CNi’ are optimal in 26.5—40.0GHz; comparing with aluminium alloy plate materials, aluminium alloy foams have some absorbing properties, and after coating absorbing paint, absorbing properties’ improvement of aluminium foams are larger than of aluminium alloy plate that were resulted from complex porous structure mainly of aluminium foams’.

Abstract: Superhydrophobic surfaces on aluminum, stainless steel, titanium alloy, and copper substrates were fabricated by nanosecond laser etching and fluoroalkylsilane modification. Compared with the existing laser beam machining technologies, such as femtosecond laser etching and picosecond laser etching, for fabricating superhydrophobic surface, the method developed by us is inexpensive and high efficiency. The influence of laser etching parameters on the surface morphology and wettability on the superhydrophobic surfaces were studied through orthogonal analysis method. The good superhydrophobicity with contact angle larger than 160° was achieved on the aforementioned 4 kinds of metals.

Abstract: At present, the performance evaluation of thermal spraying coating mainly depends on experimental test and numerical calculation, but due to the limitation of error and algorithm, neither of the two algorithms can effectively satisfy the effective evaluation of thermal spraying performance. In this paper, taking WC/Co coating as an example, a new method for calculating the performance parameters of thermal spraying coatings is proposed, that is, the finite element model and the analysis model of coating parameters are established for the microstructure of the coatings under different magnification, respectively. By calculating the basic performance parameters of the coatings, the macro performance parameters of the thermal spraying coatings are obtained, so that the performance of the coatings can be evaluated.