Advanced Materials Research Vols. 476-478

Abstract: Spherical sponge iron (SSI) with high activity and intension possesses potential characteristics to be utilized as wastewater treatment material. Influence of reduction time on specific surface area and distribution of different diameter holes were investigated. It was suggested that reductive time has significant influence on the specific surface area of SSI reduced by hydrogen under the optimized temperature. When the reductive time increased from t1 to t3, the porosity increased from 44.32% to 50.62%. While the specific surface area of SSI declined significantly from 3.089 m2/g to 0.307 m2/g when the reductive time increased from t1 to t3. On the other hand, newly formed nucleus should be combined with the adjacent formed one, and larger holes were formed. Consequently, the specific surface area of SSI declined quickly while the reduction time was prolonged, and the mean pore size varied from 275.7nm to 4611.3 nm. To utilize the SSI in wastewater treatment to remove pollutants, t1 was the optimized reductive time for its preparation.

Abstract: Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. To optimize the reduction technology, kinetic model of SSI reduction was established. The total reaction rate changing with reduction index R was deduced which describing the total reaction rate with effective diffusion coefficient De and chemical reaction rate constant k. According to the weight loss curve of SSI reduction, De and k were calculated. The total reactive rate increased with the increasing of temperature because both De and k increased with the increasing of reaction temperature. Compared De with k, it concluded that SSI reduced by hydrogen was controlled by the chemical reaction, combination of the chemical reaction and the internal diffusion, the internal diffusion when the temperature was lower than T3, from T3 to T4, over T5, respectively.

Abstract: Mechanical alloying (MA) was used to prepare pseudobinary high Pr-content Tb_0.7Pr_0.3Fe_x alloys. The structural and magnetoelastic properties were in investigated by means of x-ray diffraction and a standard strain technique. A single (Tb,Pr)Fe₂ Laves phase with MgCu₂-type structure for the composition Tb_0.7Pr_0.3Fe_1.80 was synthesized by MA and subsequent annealing process. The high magnetostriction of 600 ppm was achieved at 10 kOe for the epoxy-bonded Tb_0.7Pr_0.3Fe_1.8 composite.

Abstract: Efficient assembly of nanowires or nanotubes into functional nanodevices is one of the keys for practical application of the promising nanotechnology. Generally there are two ways for the assembly of nanowires or nanotubes: directed assembly during growth and post-growth assembly. The post-growth assembly technique is advantageous in some aspects comparatively for it puts little limitation on the nanowire or nanotube materials involved, and it can produce large nanowire arrays with better consistency. So this paper reviewed post-growth nanowire assembly techniques and discussed their advantages and shortcomings.

Abstract: The thesis studies the lock body of coil binding machine. It suggests that a convertible drive lock body just need a cylinder drive to complete lock molding, pressure strip, lock, and cut off, so as to simplify the locking body structure. This paper uses the theory of mechanism to analyze the convertible drive lock body. This paper applies Creo Elements/Pro, the 3D model software, to build up lock body model and analyses its structure. This paper also analyses the key components in FEA and strength calculation, using Pro/Mechanica module.

Abstract: Superposition principle and the higher order crack tip fields for power function are used to obtain the higher order crack tip fields for several special complex models. A new effective way is provided to solve the fracture problems of different structures and special non-homogeneous elastic materials, which establishes a theoretical basis for determing stress intensity factor, numerical simulation of higher order element and experimental analysis

Abstract: Nanostructured Fe25Al50Ni25intermetallics was prepared directly by mechanical alloying (MA) in a high-energy planetary ball-mill. The phase transformations and structural changes occurring in the studied material during mechanical alloying were investigated by X-ray diffraction (XRD). Thermal behavior of the milled powders was examined by differential thermal analysis (DTA). Disordered Al(Fe,Ni) solid solution was formed After 50 h of milling. Al(Fe,Ni) solid solution milled for 100h transformed into FeNi,FeNi3 and AlNi3 phase. The power annealed at temperature 500 results in forming of intermetallics AlFe0.23Ni0.77, Al1.1Ni0.9 , AlNi and two unknown phase after 5h milling. The nanocrystalline metallic compound was obtained after 100h milling.

Abstract: In this paper, we prepared and characterized the thiolated chitosan nanoparticles (CS NPs) Through modification. Bridged with a carbodiimide reagent, L-cysteine was therefore covalently bound to CS NPs which are capable of forming double bonds with thiol group and the mucus glycoprotein. A quantitative analysis of the widely used Ellman’s method can obtain the amount of thiol groups in various compounds. The resulted polymer conjugation displayed that the amount of thiol groups attached onto CS NPs, was increased with increasing concentration of cysteine. The method C exhibited greater conjugation ratio of thiol groups attached onto CS NPs. In particular, the evidence of thiol groups attached onto CS NPs was present in the thiolated specimens, can be shown by FTIR spectra.

Abstract: The heteropoly salt, Na₆[Mn(Mo₁₁ZrO₃₉)] •19H₂O（MnZrMo）with Keggin structure of the 1:1:11series, was synthesized by the aqueous solution method, and characterized and analyzed. The element analysis showed that the molar ratio of Mn, Zr and Mo was accord with 1:1:11;the thermogravimetric analysis/ differential thermal analysis(TG/DTA) indicated that the MnZrMo had good thermal stability and it contained nineteen molecules of crystallization water; the characterization of the fourier transform infrared spectroscopy(FT-IR),X-ray powder diffraction analysis(XRD) and the ultraviolet spectrum(UV) showed that the anionic of the MnZrMo heteropoly salt possessed Keggin structure; the analysis of the scanning electron microscopy(SEM) showed that it had the basic feature of the macromolecular compound and a regular crystal. The MnZrMo heteropoly salt was used as the catalyst to degrade the acidic-green B(AGB) dyeing wastewater enhanced by the ultrasonic, the degradation rate could reach 95.90%.

Abstract: Graphene, a two-dimensional carbon material, has attracted tremendous research interest in recent years due to its exceptional properties, such as excellent electrical, mechanical and thermal properties. Meanwhile, various kinds of novel functional materials based on Graphene oxide are employed in different fields like solar cell, sensor and catalysis. With the increasing number of catalysts during synthesizing graphene-based composites, the development of catalysis science and technology will surely be promoted. This paper reviews recent advances in the preparation and structure of graphene oxide, especially its applications in catalysis fields.