铝合金疲劳极限的测试方法

依据3种标准方法对6082-T6铝合金母材和焊接材料进行疲劳极限测试,使用升降法和波动法获得材料的中值疲劳极限,使用标准正态偏量法和单边误差限法获得材料的安全疲劳极限。结果表明：依据HB/Z 112—1986和GB/T 24176—2009,采用升降法测得的中值疲劳极限结果相同,采用波动法测得的中值疲劳极限结果差异在一个应力台阶以内;采用标准正态偏量法测得的安全疲劳极限结果较单边误差限法测得的安全疲劳极限结果高。     

硝酸含量对5083-H116铝合金板材晶间腐蚀的影响

在不同含量硝酸溶液中对6mm厚5083-H116铝合金板材进行晶间腐蚀试验,通过测量质量损失的方法来衡量其晶间腐蚀敏感性。结果表明:随着硝酸含量降低,5083-H116铝合金板材的晶间腐蚀倾向变大;当硝酸稀释至质量分数为51%时,质量损失已不满足≤15mg/cm2的标准要求。     

Influence of inorganic anions and organic additives on photocatalytic degradation of methyl orange with supported polyoxometalates as photocatalyst

A novel supported polyoxometalate(POM),phosphotungstic acid immobilized into yttrium-doped TiO2(HPW-Y-TiO2) nano photocatalyst was prepared via sol-gel and impregnation method.The samples were characterized using Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD) and N2 absorption-desorption analysis.The results showed that the supported POM exhibited Keggin structure and anatase phase with large BET surface area.The influences of inorganic anions and organic additives on the photocatalytic degradation of azo dye methyl orange with HPW-Y-TiO2 as photocatalyst under UV light(λ≥365 nm) were investigated.Results showed that inorganic anions Cl-,SO42-,CO32-and NO3-had inhibition effect on the degradation of methyl orange.A great enhancement of degradation rate was obtained while H2O2 and ethyl alcohol were applied.The degradation rates improved with the increase of H2O2 concentration.The optimum additive amount of ethyl alcohol was 0.5 mol/L.The possible mechanisms of the effects of additives on methyl orange degradation were discussed.     

Photocatalytic degradation of methyl orange by polyoxometalates supported on yttrium-doped TiO_2

A series of novel photocatalysts, H3PW12O40-Y-TiO2 nanocomposites with different H3PW12O40 loading levels (10%-40%) were prepared by impregnation method. And the Y-TiO2 support, doped with yttrium, was synthesized via sol-gel technique. The prepared catalysts were characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), nitrogen adsorption-desorption analysis and scanning electron microscopy (SEM). The processes allowed obtaining Keggin structure and crystallized anatase with large BET surface area as well as uniform distribution. The effects of H3PW12O40 loadings, catalyst dose, initial pH and concentration of dye solution on the degradation kinetics of methyl orange under UV light (λ≥365 nm) were discussed. Kinetics studies showed that the photocatalytic degradation of methyl orange fitted the apparent first-order reaction. Methyl orange was totally degraded in 21 min under optimum conditions: 20% loading, 0.03 g dose and pH 1.0. The catalyst was stable and easily to be separated from reaction system for recovery.     

ICP-OES测定5052铝合金中镁的测量不确定度评定

利用电感耦合等离子体原子发射光谱法(ICP-OES)测定5052铝合金中镁元素,分析检测过程中的不确定度来源,包括样品称量、定容、标准曲线拟合等,根据不确定度传递公式的特点,采用相对标准不确定度评定各个分量,重点评定了标准曲线拟合引入的不确定度,并对各个不确定度来源对不确定度的贡献进行评价。经计算得出合成不确定度(Yu)(c=0.0257%)和扩展不确定度(U95=0.005%)。