Single crystalline hexagonal CdS nanowires were prepared by a solvothermal method using ethylenediamine as ***/CdS nanocomposites were produced by different reduction methods and characterized by X-ray diffraction,tra...
Single crystalline hexagonal CdS nanowires were prepared by a solvothermal method using ethylenediamine as ***/CdS nanocomposites were produced by different reduction methods and characterized by X-ray diffraction,transmission electron microscopy,high-resolution transmission electron microscopy,UV-visible spectroscopy,nitrogen absorption,pulse H2 chemisorption and X-ray photoelectron spectroscopy.
Classical atomistic simulations based on the lattice dynalnics theory and the Born core-shell model are performed to systematically study the crystal structure and thermal properties of high-k Hfl-xSixO2. The coeffici...
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Classical atomistic simulations based on the lattice dynalnics theory and the Born core-shell model are performed to systematically study the crystal structure and thermal properties of high-k Hfl-xSixO2. The coefficients of thermal expansion, specific heat, Griineisen parameters, phonon densities of states and Debye temperatures are calculated at different temperatures and for different Si-doping concentrations. With the increase of the Si-doping concentration, the lattice constant decreases. At the same time, both the coefficient of thermal expansion and the specific heat at a constant volume of Hf1-mSixO2 also decreases. The Griineisen parameter is about 0.95 at temperatures less than 100 K. Compared with Si-doped HfO2, pure HfO2 has a higher Debye temperature when the temperature is less than 25 K, while it has lower Debye temperature when the temperature is higher than 50 K. Some simulation results fit well with the experimental data. We expect that our results will be helpful for understanding the local lattice structure and thermal properties of Hf1-mSixO2.
Effects of high content Cu on microstructure of hot rolled plates and microstructure, texture and magnetic properties of annealed finish product plates of non-oriented electrical steel were examined by means of EBSD t...
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Effects of high content Cu on microstructure of hot rolled plates and microstructure, texture and magnetic properties of annealed finish product plates of non-oriented electrical steel were examined by means of EBSD technique and optical microscope. The results show that surface segregation of Cu significantly hindered recrystallized grain growth of surface layer in hot rolled plate during the coiling, as a result, the surface grain sizes of the hot-rohed plates decrease with the increase of Cu content, while no sighificant change of grain size at the hot-rolled plate centre is observed. Element of Cu can obviously improve the texture types and intensity, it is found that the addition of Cu significantly increase the intensity of favorable texture and reduces, unfavorable texture in the annealed strips. The addition of 0.35%Cu can effectively improve the magnetic properties of non-oriented electrical steel, and the iron loss reaches 4.1 W/kg and the magnetic induction reaches 1.8 T.
Oxidation and ignition of magnesium alloys at elevated temperature were successfully retarded by additions of Y and Ca,which could be melted at 1173 K in air without any *** measurements in dry air revealed that the o...
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Oxidation and ignition of magnesium alloys at elevated temperature were successfully retarded by additions of Y and Ca,which could be melted at 1173 K in air without any *** measurements in dry air revealed that the oxidation dynamics curves of Mg-2.5Ca alloy and Mg-3.5Y-0.79Ca alloy at high temperatures followed the parabolic-line law or the cubic-line law.X-ray diffraction（XRD） and scanning electron microscopy（SEM） analysis indicated that the oxide film on the surface of Mg-3.5Y-0.79Ca and Mg-2.5Ca alloys exhibited a duplex structure,which agreed with the results of thermodynamic *** comparison,the ignition-proof effect of the combination addition of Y and Ca was better than that of the single addition of Ca.
Single crystalline hexagonal CdS nanowires were prepared by a solvothermal method using ethylenediamine as a solvent. Pt/CdS nanocomposites were produced by different reduction methods and characterized by X-ray diffr...
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Mg-Al bonded composite materials expand Mg and Al alloys' applications by combining their unique performances together. However, the formation of Mg-Al intermetallic compounds in interface zone of Mg/Al directly-b...
Mg-Al bonded composite materials expand Mg and Al alloys' applications by combining their unique performances together. However, the formation of Mg-Al intermetallic compounds in interface zone of Mg/Al directly-bonded joint seriously obstructs its further development. To solve this problem, Mg-Ag-Al multilayer composite materials have been successfully prepared by diffusion bonding technology. The effect of key process parameter (bonding temperature) on microstructure of this material has been mainly investigated. The results show that Mg and Al were well bonded by using silver interlayer when the bonding temperature exceeded 370°C. But Mg17Al12 and Mg2Al3 compounds were formed in the interface zone at temperatures higher than 420°C. By means of controlling the bonding temperature (380 °C–420 °C), silver interlayer effectively restrained the generation of Mg-Al intermetallic compounds, and Mg-Ag intermetallic compounds (Mg3Ag, MgAg) were formed in the interface zone instead.
Introduction Many studies focused on using lignocellulosic biomass as an ideal feedstock for producing biofuels. By comparison, other bioresources, for example rosin fromthe pine tree, received less attention
Introduction Many studies focused on using lignocellulosic biomass as an ideal feedstock for producing biofuels. By comparison, other bioresources, for example rosin fromthe pine tree, received less attention
The downgraded and upgraded BaZrxTi2−xO5 (x=0, 0.01, 0.02, 0.03 and 0.04) films normal to Pt/Ti/SiO2/Si substrates were prepared by sol-gel method. The microstructure and dielectric properties of the compositionally g...
The downgraded and upgraded BaZrxTi2−xO5 (x=0, 0.01, 0.02, 0.03 and 0.04) films normal to Pt/Ti/SiO2/Si substrates were prepared by sol-gel method. The microstructure and dielectric properties of the compositionally graded BaZrxTi2−xO5 films were investigated. The single-phase downgraded and upgraded films were obtained as the films were annealed at 900 °C for 30 min. The downgraded BaZrxTi2−xO5 film had dense surface, while there were pores in the surface of the upgraded BaZrxTi2−xO5 film. The thicknesses of both upgraded and downgraded BaZrxTi2−xO5 films were about 500 nm. The values of permittivity (r) for the downgraded and upgraded BaZrxTi2−xO5 films were 84 and 100, respectively, at 1 MHz.
Supercritical carbon dioxide (ScCO2) foaming which is inexpensive and environmental friendly has been widely used to prepare polymer-based microporous materials. In this paper, PMMA graded microporous materials were f...
Supercritical carbon dioxide (ScCO2) foaming which is inexpensive and environmental friendly has been widely used to prepare polymer-based microporous materials. In this paper, PMMA graded microporous materials were foamed by PMMA matrix after an unstable saturation process which was done under supercritical condition of 28MPa and 50 °C. The scanning electron microscopy (SEM) was utilized to observe the morphology of the graded foam. A gas adsorption model was proposed to predict the graded gas concentration in the different region of the polymer matrix. The SEM results showed that the solid and foam region of the graded foam can be connected without laminated layers. With the increasing thickness position of the graded microporous foam, the cell size increased from 3.4 to 27.5 μm, while the cell density decreased from 1.04 × 109 to 1.96 × 107 cells/cm3. It also found that the gradient microporous structure of the foam came from graded gas concentration which was obtained in the initial saturation process.
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