Advanced Materials Research Vols. 490-495

Abstract: Modification of attapulgite by KH-570 for formaldehyde adsorption and characterization of the resulting sorbents by SEM, BET, FT-IR and TG-DSC were conducted, as well as the test of the breakthrough curves of formaldehyde dynamic adsorption. The results show that KH570 was grafted with the surface silanol group of attapulgite. The adsorption capacity of attapulgite for formaldehyde was improved significantly by KH-570, which has a certain utility to remove the formaldehyde gas in the air.

Abstract: A central composite rotatable design combined with response surface methodology was employed to study the effect of microwave assisted extraction (MAE) conditions namely microwave power, extraction time, liquid-solid ratio and ethanol proportion on the proanthocyanidins extraction from purple cabbage. The optimum extraction conditions were as follows: microwave power, 260 W; extraction time, 54s; liquid to solid ratio, 43; and ethanol concentration, 57%. The results showed proanthocyanidins had a significant effect on scavenging of DPPH radicals. At last, proanthocyanidins were identified by thin layer chromatography.

Abstract: In order to reduce the low-frequency line spectrum of double cylindrical shell, the research was done to apply composite damping steel plate in acoustic bridge between two shells. By suppressing vibration energy transmission along acoustic bridge, two types of composite damping rib-plate were designed with the resistance increasing technology based on the principle of damping vibration attenuation. Then the vibro-acoustic characteristics of double cylindrical shell were analyzed through numerical calculations, considering original and improved acoustic bridge. The results shows that: composite damping steel plate applying in acoustic bridge can reduce sound radiation of double cylindrical shell effectively, properly increasing damping between composite plates is beneficial for vibration and noise reduction. These research results could be a reference for submarine acoustic stealth design.

Abstract: Anodized composite films containing n-SiC and PTFE particles are prepared on 2024 Al alloy by anodization in phosphoric acid-base electrolyte and ultrasonic impregnation and subsequent heat treatment. Results show that the oxide film microhardness increase with n-SiC content and ultrasonic impregnation time increase, the oxide film wear extent decrease with n-SiC and PTFE content increase basically. The composite films formed on optimum conditions have reduced friction coefficients and relatively high microhardness. The friction coefficient can be as small as 0.14, while the microhardness can reach as high as 429 HV, which is much better than that of an oxide film prepared under the same conditions but without adding any particles. This indicates that the synthesized composite films have good anti-wear and self-lubricating properties

Abstract: Through the introduction to the properties of characteristic polynomial, the order reduction theorem of the characteristic polynomial as well as its application in high order matrix is studied, and also a simplified method (characteristic polynomial method), which is used to solve the particular integral of the non-homogeneous linear differential equation with constant coefficients, is proposed in this paper. It is simpler than coefficient comparison and Laplace transform method, and also is of greater realistic significance for the differential equations with high order number and terms number.

Abstract: Bismuth aluminate is a kind of antacid medicine which is used to treat peptic ulceration and nervous dyspepsia. In our experiment, a simple solution strategy via supersonic method for the synthesis of spherical bismuth aluminate nanoparticles at room temperature is presented. During the procedure, bismuth aluminate was directly precipitated from the solution in the ultrasonic syringe under strong alkaline condition and its chemical empirical formula was defined by inductively coupled plasma(ICP) analysis, element analyzer(EA) and analysis analysis. XRD, FTIR and TEM, have been employed to characterize the obtained nanocrystals. Preparative parameters, such as the pH value, drying temperature and the sonication time were optimized to obtain Bi2(Al2O4)3•10H2O nanomaterials with considerable yield, uniform shape and narrow size distributions.

Abstract: By adding tannic acid and film-forming accelerator in the treatment solution containing titanium and zirconium ions, a golden conversion coating on the surface of aluminum alloy was prepared. The main component and corrosion resistance of the conversion coating were characterized by means of EDS, SEM, XRD and electrochemical workstation. The conversion coating was golden and showed as uniform cubical crystal. results also showed that the main component of the conversion coating was Na3AlF6. In potentiodynamic polarization test, the corrosion current density of the aluminum alloy decreases to 0.083 A•cm-2 from 5.894 A•cm-2, which indicated an obvious improvement of corrosion resistance.

Abstract: Based on the parallel bonding mechanism of IC chip die designed, the static stiffness model is established. Static stiffness characteristic curves are drawn in whole working place through Matlab software, the infection which created by the left/right driving parts and connecting rods are analyzed. It proves that the parallel bonding mechanism designed meets the working requirements of IC chip die by these characteristic curves.

Abstract: The self-propagating high-temperature spraying synthesis (SHSS) route is evaluated for the synthesis of ferrite powders that are subsequently processed towards the manufacturing of high initial magnetic permeability. The powder samples are used for characterization by SEM, EDS and XRD. The results show that the obtained particles are hollow microspheres from nanometer dimension to several micrometers. The phase structure of hollow microspheres is the mixtures of ferrite and Fe2O3. Permittivity and permeability measurements are made on particles dispersed in a paraffin wax matrix. The microsphere is a ferromagnetic matter with both high magnetic loss and high dielectric loss.

Abstract: An orthogonal experiment is conducted to study the effect of activation temperature, activation time and the ratio of KOH to carbon material (i.e. the mass ratio of KOH to coking fly ash) on the adsorption capacities of the activated carbon made by using coking fly ash as the raw material and KOH the activating agent. The results show that the three factors can be ordered as activation temperature, activation time and the ratio of KOH to carbon material according to the significance in their effect on preparation of activated carbon from coking fly ash. In addition, the optimum activation temperature is 850°C, optimum activation time 30minutes, and the optimum ratio of KOH to carbon material 4:1. For the activated carbon made under these conditions, the iodine absorption capacity is 874.3774mg/g, specific surface-area 275.51m2/g, the mean pore diameter 47.75nm and total pore volume 0.1172cm3/g. As the proportion of mesoporouses reaches 71.57%, the activated carbon made from coking fly ash is good for absorption of those absorbates with higher molecular weights.