The influence on immersion time of titanium conversion coatings on electrogalvanized steel

The study aims to replace chromate treatments of electrogalvanized steels by immersing the electrogalvanized steel in a titanium trichloride (TiCl₃) bath. The influence of immersion time on surface morphology and corrosion resistance of the titanium conversion coatings was investigated. The titanium conversion coating prepared for 300 s immersion time with a uniform structure has the most excellent anticorrosive performance. Furthermore, the coating comprises a loose outer layer and a dense inner layer structure with a thickness of 150 nm. X-ray photoelectron spectroscope analysis shows that the coating consisted of Zn and Ti oxides and/or hydroxides.     

合成丙酮酸及其酯类的反应体系热力学计算与分析

采用Yoneda基团贡献法估算了丙酮醛、丙酮酸和丙酮酸甲酯的标准生成焓Δ_f H_m~θ、标准S_m~θ以及拟合等压热容曲线。结合丙酮醛氧化酯化合成丙酮酸及丙酮酸甲酯反应的热力学数据,对丙酮醛氧化制备丙酮酸及丙酮酸酯化制备丙酮酸甲酯的摩尔焓变Δ_rH_m~θ,吉布斯自由能变Δ_r G~θ和反应平衡常数K进行了计算与分析。结果表明,丙酮醛氧化制备丙酮酸的反应为强放热反应,标准状态下Δ_r_m~θ;为—319.3 kJ/mol,丙酮酸酯化制备丙酮酸甲酯的反应为弱的放热反应,标准状态下Δ_rH_m~θ成为—61.73 kJ/mol;两个反应的吉布斯自由能变在考虑的温度范围内均为负值,且丙酮醛氧化温度为450K时,反应的焓变有最小值—345kJ/mol丙酮酸及丙酮酸甲酯的转化率较高。     

用古马隆制取酚醛树脂常温固化剂的研究

介绍了以古巴隆为原料制取的热固性酚醛树脂常温固化剂的性能、影响因素及固化条件，提出了用常温固化剂鉴别酚醛树脂的粘结性能及预测镁碳砖耐压强度的方法。     

Quality Control Parameters for Robotic Bridge Painting

To protect a steel bridge from corrosion, periodic painting is needed. Bridge painting operations are dangerous and hazardous to human health. A robotic bridge painting system is being developed to replace the human being. One major problem with robotic bridge painting is how to achieve the specified coating quality, which includes two aspects: (1) the coating thickness; and (2) the coating appearance. To ensure quality of the robotic bridge painting, the writers have investigated: (1) the parameters that affect the coating thickness and appearance; (2) the values of the parameters to achieve the required thickness and appearance for the robotic painting; and (3) the thickness distribution functions of the bridge painting under various conditions. The specified painting quality can be achieved by using the results of this study to set up and control the robotic bridge painting system.     

Zero-forcing equalizability of FIR and IIR multichannel systemswith and without perfect measurements

We study the linear zero-forcing equalizability of a communication channel. Necessary and sufficient conditions are given in terms of the zeros of the transfer function. Detailed procedures of equalizer design for minimum sensitivity with respect to modeling errors and white noise are also presented. It is found that the worst case effect of channel mismatch on the performance may be modeled as equivalent losses in signal-to-noise ratio     

高速光纤通信线路DmB1M码型初探

本文介绍分析一种适合超高速光传输线路码型——DmB1M码的构成及其功率谱特性;并试制了D10B1M码的编/解码器;认为该码型有其独特的优点并适于超高速光传输系统。     

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根据储层物性参数以及其它影响因素,应用模栩数学建立了孔眯性玻酸盐岩储集层分类数学模型,并进行了纬合评刹分类.此法克服了长期以来储集层分类的片面性和机械性,使分类更加科学。     

地震相模式识别

地震层序内包含着不同的地震相带。地震剖面上对应于不同沉积相带可能呈现出不同的地震相特征,即不同的地震相模式。由地震剖面提取地震层序的地震相特征参量,并通过统计模式识别的方法划分出不同的地震相带,根据地震相带所具有的反射特征并结合钻井资料和其它地质资料可进行沉积相推断解释。对三角洲、冲积扇和湖盆三类陆相沉积地质模型的合成地震记录理论样本进行了分类试验,正确识别率达85％;对实际地震剖面也进行了试验,证明有用于实际资料的前景。     

白带，女性健康的晴雨表

女人，没有不希望自己所爱的人忠诚、专一的，所以在任何情况下都不能允许他好“色”，但女人对自己衣着的色彩却总是挑剔了又挑剔。