Corrosion inhibition of ammonium molybdate for AA6061 alloy in NaCl solution and its synergistic effect with calcium gluconate

The corrosion inhibition of ammonium heltamolybdate (AH) and calcium gluconate (CG) for AA6061 alloy in 3% NaCl solution was investigated by the electrochemical measurements. It indicates that AH inhibits the corrosion of AA6061 alloy and acts as an anodic inhibitor. Maximum inhibition efficiency reaches 74.3% at the concentration of 1 × 10^?4 mol.l^?1 AH. The results of the electrochemical studies reveal AH is physically adsorbed on the AA6061 alloy surface and the adsorption follows Langmuir isotherm. The combination of AH and CG enhances the inhibition efficiency to 95.9%. The enhanced inhibition is attributed to the promotion of AH adsorption by CG. The mixture of AH and CG is a mixed‐type inhibitor and renders the corrosion potential to more positive values. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of tetrasubstituted thiophenes from pyridinium 1,4-zwitterionic thiolates and modified activated alkynes

Pyridinium 1,4-zwitterionic thiolates were applied to a formal [3 + 2] annulation reaction with modified activated alkynes, affording various tetrasubstituted thiophenes with aryl, alkenyl, alkyl or silyl group at the special position. The structural modification of alkyne substrates enabled the synthesis of diverse thiophenes to be achieved using the pyridinium 1,4-zwitterionic thiolates as the sulfur-containing building blocks. This approach is metal-free and catalyst-free.     

石油醚在流体静高压下的超声声速、衰减、密度和绝热压缩系数

 专门设计了用脉冲-回波-重合法在不同静水压下测量液体声速的装置，并对石油醚在0.1~650 MPa流体静压力范围内测量了其超声声速和衰减系数。还通过测量体积压缩量和质量得到石油醚密度ρ随流体静压力的变化。最后，给出了石油醚的绝热压缩系数β与流体静压力的关系。     

压电振子的多维耦合振动（Ⅱ）——复合压电振子

本文利用表观弹性法分析了复合压电振子的三维耦合振动的基频本振方式,得到了振子共振频率的很简单的解析表达式并由此计算了频率常数随振子尺寸变化的关系曲线。本文的计算结果同已发表的用有限元法计算的结果满意地符合。由于计算公式十分简单,因此共振频率的计算可以用微型计算器很快计算出来而无需用电子计算机,所以这种方法对工程设计和估算来说要比有限元法简便得多。
此外,还给出了有限长圆柱中“纵波”相速的频散公式,并与无限长圆柱中的公式进行了比较。
本方法也可用来计算其它复合压电振子的共振频率。     

恒星对增长螺旋引力扰动的非线性响应及其对增长模式的致稳作用*

本文计算了在增长的螺旋扰动引力场中恒星响应的非线性效应.结果表明,这一非线性效应会导致Q值的增加,从而降低增长率.对于振幅很小,增长率也较小的螺旋形模式,Q值增加较慢;对于振幅较大或增民率较大的模式,Q值也增加较快,从而有效地抑正振幅的增长.这一调节机制是使得由线性理论所得出的增长模式最终达到准稳状态的原因之一。     

SO_2和NO_2在γ-Al_2O_3(110)表面吸附的第一性原理计算

采用基于平面波基组的Vienna Ab-initio Simulations Package (VASP)程序研究了SO_2和NO_2在γ-Al_2O_3(110)表面和羟基化γ-Al_2O_3(110)表面的吸附,获得了SO_2和NO_2吸附的不同构型和结构参数.对吸附能,电荷转移,差分电荷密度和投影态密度等进行分析和讨论.对比发现,在γ-Al_2O_3(110)表面SO_2的吸附能力强于NO_2.SO_2或NO_2在非羟基化γ-Al_2O_3(110)表面吸附时O原子的2p轨道和Al原子的3s3p轨道作用形成O-Al键,且SO_2吸附时键结强度高于NO_2.NO_2吸附时费米能级以下有部分反键态,削弱了与γ-Al_2O_3(110)表面相互作用.在羟基化γ-Al_2O_3(110)表面SO_2或NO_2的吸附能力会低于非羟基化表面,但是SO_2的吸附能力依旧强于NO_2.计算结果说明SO_2与γ-Al_2O_3(110)表面的相互作用强于NO_2.以上研究,将有助于理解SO_2和NO_2在γ-Al_2O_3的反应性,为进一步研究它们的非均相转化和在灰霾形成中的促进作用奠定基础.     

Affective property of image and fractal dimension

Affective information processing is an advanced research direction in the AI world. Affective Information of image was taken as the objective of research in this paper. The influence of color vision properties’ histograms of image on human emotions was analyzed. Then based on fractal theory, the fractal aspect of different kinds of images was analyzed in keeping with the space domain. After that, psychological testing method of semantic difference was applied to verify the uniformity of the objective and subjective evaluations. At last, a conclusion was drawn that image having different affective properties could be classified by their fractal dimensions.     

具P-Laplacian算子型周期边值问题解的存在性

本文利用拓扑度理论和一些分析技巧讨论了具p—Laplacian算子型周期边值问题(φp(χ’))’+d/dt gradF(χ)+gradG(χ)=e(t),χ(0)=χ(T),χ’(0)=χ’(T)解的存在性,在对阻尼项d/dtgradF(χ)没有任何限制的前提下,给出了解存在的充分条件.     

横观各向同性多孔超弹性矩形板的单向拉伸

利用横观各向同性超弹性材料的广义neo-Hookean应变能函数研究了含有多个微孔的超弹性矩形板在单向拉伸作用下的有限变形和受力分析.给出了含有某种对称性分布的多个微孔的矩形板的变形模式,通过求解该变形模式满足的微分方程,将它用两个参数表示出来.可应用最小势能原理导出变分近似解,从而得到矩形板的变形和应力分布的解析解.分析了板中微孔的增长及微孔边缘应力的分布情况,讨论了板的各向异性程度及微孔的大小和孔间距离的影响,得到了单个、三个及五个微孔板中微孔的增长变形和孔边应力分布的一些基本规律规律,并进行了相互比较.