Advanced Materials Research Vols. 295-297

Abstract: A series of Cu-based catalysts for the synthesis of indole by the reaction of aniline and ethylene glycol were prepared and characterized by ICP-AES and XRD. The results indicated that the activity and stability of Cu/SiO₂ catalyst was increased after adding Zn, Mn, Cr and Fe promoters. Mn promoter was favorable for the dispersion of Cu, Zn, Cr, Fe and enlarged the specific surface area of catalysts. It could be seen that the catalysts prepared by impregnation method had better stability and higher activity than the catalysts prepared by co-precipitation method. The catalysts with small grain size of Cu had higher activity than those with big grain size. Some catalysts showed excellent performances in this reaction.

Abstract: Ti-Al nanoparticles and have been synthesized by the flow-levitation (FL) method. The morphology, crystal structure and chemical composition of Ti-Al nanoparticles obtained were investigated by transmission electron microscopy, X-ray diffraction and induction-coupled plasma spectroscopy. Results showed that the average grain size of these nanoparticles is about 30 nm, and it can be controlled availably by altering procedure parameters. The structure of powder is mainly double phase Ti-Al particulate composite. In addition, there are certain corresponding relation between the compositions of evaporate source master material and phase composition of alloy compound nanoparticle. The expected nanoparticle, which is mainly composition of nanocrystalline intermetallic compound, can be obtained through changing the compositions of evaporating source mastermaterial.

Abstract: The N₂H₄–KHB reduction then CH₃OH watering and H₂ reduction system was used to make superfine nickel powder by using nickel sulfate as material.The superfine nickel powder of the specific surface area of the nickel powde being 4.24m²/g, spheric shape with grain size 0.5-0.9μm,nickel content being over 99.5%,The toll nichel recovery being over 99.5% was made on the condition of reaction temperature 60°C, reaction time 150-180min,pH 8.0-8.5,[Ni]=1.25M,N₂H₄/Ni=1.35（mol ratio）,sodium hexametaphosphate of 1.5‰ as additive，the dosage of KHB of 8.37×10^-3g/g Ni and washing by carbinol,reducing by H₂.

Abstract: This paper established the model based on Step-by-Step forming in ABAQUS firstly, we set synchronous alternating circular motion on the upper and lower die with the amplitude curve, its has implemented the die design and the path trail about Step-by-Step forming section.

Abstract: In this paper, the solidification and heat transfer of a 60t huge rectangular ingot has been simulated. The solidification rate at pouring finish and the solidification times were simulated for air cooling, soft wind cooling, strong wind cooling, fog cooling, weak water cooling and strong water cooling. Mathematical simulation results tell us that by intensive cooling, the solidification time of the can be obviously shortened, internal soundness can be ensured and the surface quality could be improved.

Abstract: Dial indicator can be used to adjust skateboard to turning cone. First, the characteristics of traditional methods is introduced. Then, the step of skateboard rotation angle’s adjustment with dial indicator is analyzed. Before turning workpiece, the rotation angle of skateboard can be adjusted by the workpiece and taper plug, the rotation angle of skateboard also can be adjusted by tailstock sleeve and workpiece, and then the workpiece can be directly turned to the accuracy requirements dimensional. The rotation angle of skateboard is adjusted before processing, so it can avoid the repeated measurements and adjustment in the process, Therefore, this method can save processing time and improve the accuracy of the taper.

Abstract: Discrete mass gain method is adopted to determine the oxidation kinetic behaviors of 2Cr12NiMoWV steel in water vapor at 540°C and 17.5 MPa. Results indicate that the kinetic curve of the oxidation experiences a dramatic turning where the oxidation has lasted 20h, namely, the oxidation is faster than before the oxidation point of 20h, then oxidation rate is greatly reduced;, and after the oxidation has lasted for 300h, its reaction is inhibited to enter into a relatively stable period. The test analysis of oxide film under scanning electronic microscopy and electronic probe microanalyser shows that the formation process of the oxide film is as follows: needle-like oxide nuclei → short-strip oxide → fine equiaxed crystal grains → large equiaxed crystal grains or columnar crystal particles. The alloying elements involved in oxidation represent the law as follows: Fe, Mo and Si react with vapor at the initial stage of oxidation reaction to form Mo and Si-contained Fe-rich oxide. As the oxidation reaction proceeds, Cr gathered at the interface between the surface oxide film and the matrix, is internally oxidized. The Mo, Si and Cr in the surface oxide will be continuously volatilized with the occurrence of oxidation reaction.

Abstract: LiNi_0.4Co_0.2Mn_0.4O2 samples was synthesized via urea co-precipitation method. The XRD, SEM and electrochemical measurements were used to examine the structure,morphology and electrochemical characteristics, respectively. LiNi_0.4Co_0.2Mn_0.4O2 powders show excellent electrochemical performances. The optimum sintering temperature and sintering time are 800°C and 20 h, respectively. The LiNi_0.4Co_0.2Mn_0.4O2 powders shows the discharge capacity of 145.1 mAh·g^-1 in the range of 3.0-4.5 V at the first cycle, and the discharge capacity remains 132.3 mAh·g^-1 after 30 cycles. The urea co-precipitation method is suitable for the preparation of LiNi_0.4Co_0.2Mn_0.4O2 cathode materials with good electrochemical performances for lithium ion batteries.

Abstract: In order to simplify the nonlinear analysis of reinforced concrete, a new study on concrete strength criterion under tension condition is made, and more simple and accurate practical calculation equations are put forward. The results from the equations agree well with the experimental data.

Abstract: According to the analysis of the current chloride ion eroding model, it has been known that diffusion coefficient and chloride ion concentration on the concrete’s surface are random variables. Meanwhile the concrete protective thickness is also random variable because of manufacturing error and other reasons. So the diffusion process is the random process in fact. The random calculation model of chloride ion concentration in concrete has been deduced from the current model with the help of mathematical knowledge in this paper. Moreover, a satisfied effect has been achieved after comparing the calculated values with the test values. The calculation model is proved to be useful for life prediction and assessment of concrete structures.