Advanced Materials Research Vols. 396-398

Abstract: A new method for the determination of manganese in food grade FeSO₄•7H₂O samples by flame atomic absorption spectrometry (FAAS) after solid phase extraction was developed. The research showed that when coexistent amount of iron was greater than or equal to 100 times of manganese, the relative error of direct determination of manganese by FAAS was greater than or equal to +5%. Firstly, Fe²⁺ was oxidized to Fe³⁺ by HNO₃. Fe³⁺ was masked by EDTA. Mn²⁺ ions were then adsorbed by strong acid cation exchange fiber (SACEF) in pH 1.5 sample solution for 10 minutes and eluted by 2.5 mol/L HNO₃ for 15 minutes. Iron and manganese can be effectively separated by this method. Under the optimum conditions, the adsorption capacity of SACEF to Mn²⁺ ions was attained to be 9.27 mg•g^-1. The detection limit of the method was 0.032 μg•mL^-1. The proposed method was used for determination of manganese in three batches of FeSO₄•7H₂O samples. The contents of manganese were 325 μg/g, 823 μg/g, 772 μg/g respectively. The recoveries were in the range of 96.1%~103 % and RSDs (n=5) were less than 3.0%.

Abstract: In this paper, We studied the technical issues of fully mechanized caving under aquifer in Tiebei mine of Zhalainuoer mining company，carry on analysis and studies from the electrical and mechanical equipment to the technical management and gave the solution, with some reference value. It is hard to mine one by one coal seam due to hydrogeology and deposit of2a seam, Tiebei mine. For example, It is hard to solve top seam management, hydrogeology management and coal Spontaneous combustion. For getting more coal and extend the service life of mine, We started trial coal mechanized caving under aquifer in 2004 on the research basis. At the beginning of coal mechanized caving, We encountered equipment problems, equipment assort usage problems，produce management problem, coal caving method problem, use of face-end support problem, water management problem, and so on. By continuously review experience and exploring ,We solved the problems one by one. So we gained coal mechanized caving under aquifer valued experience.

Abstract: In this article, a novel structure poly(N-isopropylacrylamide) (PNIPAM) hydrogel, which is featured with both ends of linear PNIPAM chains being grafted onto semicircular and cross-linked PNIPAM chains, has been successfully prepared in a three-step process by a method of sequential synthesis for the first time. The proposed hydrogel displays faster and hydration/dehydration dynamic response to temperature cycling owing to linear PNIPAM chains to form big-hole structure. This work may be highly attractive for targeting drug delivery systems, polymeric machinery, and sensors and so on.

Abstract: Abstract. Gas-solid fluidized beds are widely applied in many industries as reactors or heat/mass transferring units because of their good heterogeneous mixing behaviors and large transferring area between the gas and solid phases. In this study, based on the Eulerian-Eulerian approach, 2D model of gas-solid flow field in fluidized bed is simulated, and the drag force models of Gidaspow and Syamlal-O’Brien have been used to simulate and analyze the two-phase flow for exploring mechanism and interaction laws of two-phase flow.

Abstract: In this research, 4045/3004/4045 composite ingots were obtained by a semi-continuous casting process. The macrostructure, microstructure, elements distribution, mechanical properties of 4045/3004/4045 triple layers composite were studied. The results show that the composite interface is planar and clean with little evidence of porosity can be achieved by an optimum semi-continuous casting technology. The thickness of diffusion layer near composite interface can be controlled less than 30 μm. The bonding strength can reach to 100MPa which belongs to a kind of metallurgical bonding.

Abstract: Numerical specimens with ramdom joints is established by particle flow code PFC2D and uniaxial compression tests are conducted under three different loading rate. Studies have shown that strength of uniaxial compression are all increased with the loading rate no matter what specimen is complete or with random joints. The sensitivity of changes of uniaxial compressive strength of specimen with random joints decreases with increasing of the loading rate.

Abstract: this paper, four kinds of Chinese herbal medicines from Enshi：Camptotheca acuminata, Paris polyphylla Smith, Taxus mairei and Trillium tschonoskii Maxim were respectively extracted by double distilled water, 0.5mol/LNaCl solution, and 75%(v/v) ethanol,using pyrogallol autoxidation method to test the antioxidant activity. The results showed that four kinds of Chinese herbal medicines have certain ability to remove superoxide anion radical and different among them, The ethanol extract of Camptotheca acuminata and water extract of Trillium tschonoskii Maxim have the strongest antioxidant capacity,however all of the salt extract of four Chinese herbal medicines which can hardly remove superoxide anion radical have little antioxidant capacity.

Abstract: Taking the paste of used lead acid batteries as studying object, reaction mechanisms and experiments were investigated between citric acid and PbO, PbO₂ and PbSO₄. The results showed that: three reactions Gibbs function, between the citric acid and the PbO, PbO₂ and PbSO₄, were less than zero, and the reaction could be spontaneous; XRD results showed that: the above three reactions could produce lead citrate, and after roasting of the three kinds of lead citrate precursor, the powders, Pb/PbO as their main ingredients, could be obtained at low reaction temperature.

Abstract: Transparent Al doped ZnO (AZO)/acrylic resin composites, as glass thermal insulation coating, were prepared by incorporating AZO nanoparticles into transparent acrylic resin matrix. Firstly, AZO powders were synthesized by sol-gel method. Then transparent heat-insulation coating of AZO/acrylic resin was prepared by the blending method. The results show that the transparent heat-insulation coating had good chemical stability and mechanical properties; under the irradiation of infrared lamp for 10 minutes, the temperature difference between the coated glass and bland glass achieved 13.8oC.

Abstract: The magnetostatic interaction, the coercivity and the figure of merit of an irregular triangular nanowire array are studied with the help of Neel model. The results show that the broadening of the distribution of nanowire lengths decreases the thermal stability of the array and the minimum figure of merit is a good candidate for measuring the system’s thermal stability.