Validity of dynamic electrochemical impedance spectra of some amine corrosion inhibitors in petroleum/water corrosive mixtures by Kramers-Kronig transformation

In our previous works, the corrosion inhibition properties of propylamine (PA), iso-propylamine (i-PA), butylamine (BA), tert-butylamine (t-BA), hexylamine (HA), ethylenediamine (EDA), diethanolamine (DEA), 3-amino-1-propanol (3-AP), 2-dimethylethanolamine (2-DEA), cyclohexylamine (CHA), N-methylcyclohexylamine (N-MCA) and dicyclohexylamine (DCHA) have been investigated by means of electrochemical impedance spectroscopy (EIS) with a carbon steel rotating disc electrode in some petroleum/water corrosive mixtures containing acetic acid and NaCl at 25 °C. In this work, the Kramers-Kronig transformations (KKTs) were applied to evaluate the validity of the impedance data of these amine compounds in hydrodynamic condition. The results obtained showed that experimental impedance data did not satisfy in K-K relations completely viz. indicated some errors. These errors were related to stray capacitances, external transmission line effects, pits formation and change in interface during data acquisition at high and low frequencies regions. In addition, the selection of a suitable equivalent circuit strongly emphasized to better interpret of EIS data which in turn cause better resulted KKTs spectra. With considering obtained transformations, more effective inhibitor was selected with regard to its charge transfer resistance, the corrosion capacitance and well satisfying in K-K relations.     

B4C涂层作为等离子体面对材料的一些性质

介绍了利用等离子喷涂设备,B4C/Cu梯度功能涂层及非梯度涂层的制备技术,在模拟实验装置中测量了在高能粒子(3 keV,D+)的作用下,B4C涂层的化学溅射产额、热解吸性能、热冲击性能及热导率.结果表明B4C是一种有希望为未来聚变装置中等离子体面对的材料.     

不规则I型和L型横截面形状薄壁杆件的横向弯曲稳定分析

根据势能驻值原理,采用转换B3样条函数模拟杆件横截面的翘曲位移场,文[8]提出了用于分析在横向荷载作用下薄壁杆件稳定问题的样条有限杆元法。方法适用于任意横截面形状和任意边界条件的薄壁杆件,考虑了杆壁中面上剪切变形的影响,能很好地描述剪力滞后现象。本文讨论了不规则I型截面简支梁和L型截面简支梁的屈曲分析,数值算例的结果表明了方法的灵活性、精确性和有效性。     

光纤专用网中基于DSP的Q值在线检测模块的设计

基于误码率与Q值的对应关系，本文介绍一种Q值在线检测方法，模块设计采用DSP技术，并讨论了该模块在光纤工业专用网（FIN）中的应用。     

TiB2与BN复相陶瓷的渗流模型

试验结果证实,TiB₂与BN复相陶瓷的导电性能符合渗流理论,原料粉粒度配比下,其渗流阀值为V_c%=22.9%;原料粉粒度比的改变将改变渗流阀值,从而改变各配比下的电阻率值;TiB₂与BN在SPS系统中快速烧结,晶粒的尺度比与原料粉的粒度比基本保持一致。     

Dissolution of Ti wires in sulphuric acid and hydrochloric acid solutions

Ti wire electrodes were immersed in acidic solutions containing H₂SO₄ and HCl of various concentrations at 353 K to evaluate corrosion rate by measurement of electric resistance change (resistometry). Addition of hydrochloric acid to sulphuric acid solution promoted depassivation of Ti. After depassivation, the immersion potential dropped to the hydrogen evolution potential and a hydride layer was formed on the surface. The hydride layer dissolved continuously in the acidic solution. SEM observation showed that Ti wires dissolved almost uniformly in the early stage and that the dissolution then trace became irregular due to nonuniform growth of the hydride layer. Dissolution rate of a Ti wire was estimated almost accurately by resistometry.     

Aflatoxin B1 contamination of shrimp feeds and its effect on growth and hepatopancreas of pre-adult Penaeus monodon

A survey of aflatoxin B₁ (AFLB₁) levels in commonly used commercial shrimp finisher feeds in the Philippines showed a various range of values from not detected to 120 μg kg^?1 using high-performance thin-layer chromatography. Six experimental diets were prepared to contain various levels of AFLB₁ based on survey results to determine the effects of such contamination in pre-adult shrimp Penaeus monodon (17.5 ± 0.6 g). Results showed that shrimps fed diets containing AFLB₁ greater than or equal to 73.8 μg kg^?1 gave comparatively poor growth rate and higher susceptibility to shell diseases. No AFLB₁ residues were detected in sampled whole shrimp tissues after 62 days of exposure to AFLB₁ containing diets indicating a low potential for transmission of the toxin from edible shrimp tissues to consumers. Histopathological alterations in the hepatopancreas of shrimp chronically exposed to AFLB, were observed in all samples. The degree of alterations correlated with the level of AFLB₁. Based on growth performance, pre-adult shrimps can tolerate AFLB₁ levels of up to 52.3 μg kg^?1 in the feeds although histopathological changes were already evident in the tissues of shrimps given diets with 26.5 μg kg^?1 AFLB₁.     

B. F. Skinner: Au-delá de la controverse.

Discusses controversies surrounding the work of B. F. Skinner's influence on various theories of human and animal behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

一种新型均速管流量计在高炉煤气测量中的应用

高炉煤气具有管径大、流速低、粉尘大、易堵塞等特点，其流量用常规装置测量效果不尽理想。近来，一种新型均速管流量计——威力巴流量计采用独特的结构设计，在高炉煤气流量测量中取得了不少进展。本文对威力巴流量计的基本原理和应用于高炉煤气测量的突出优点进行了分析，并给出了安装使用时的一些建议。