Effect of anodizing on galvanic corrosion behavior of T300 CFRP/5083P-O Al bolted joints

T300 carbon fiber reinforced polymer (CFRP) and 5083P-O aluminum (5083P-O Al) alloy bolted joints have been used in high-speed trains due to the advantages of light weight and high strength. However, high potential difference between the CFRP and 5083P-O Al will induce galvanic corrosion and result in accelerating corrosion rate of 5083P-O Al, which is a potential risk for its engineering applications. In this work, combination with the electrochemical analysis, surface and cross-section corrosive morphologies analysis, the galvanic corrosion behavior between CFRP/5083P-O Al bolted joints with and without anodizing in 3.5 wt.% NaCl spray was investigated. Results indicated that severe corrosion occurred on unanodized 5083P-O Al in the coupled regions of the CFRP/5083P-O Al bolted joint due to galvanic corrosion. With the content of sulfuric acid increasing, the thickness of each Al₂O₃ layer and atomic oxygen content increases significantly. 5083P-O Al anodized by the 135 g/L H₂SO₄ + 8 g/L H₃BO₃ mixed solution had the favorable Al₂O₃ film, which increased the resistance of 5083P-O Al by roughly three orders of magnitude, effectively improving the corrosion resistance of 5083P-O Al.     

涂装车间节水方案企划与实施

某涂装车间在现有节水措施的基础上,通过企划与实施一系列新的技术及精益管理措施,如,磷化出槽喷淋工艺优化、纯水制水率提升、空调冷凝水回用率提升、中水深度处理回用、用水分级管理等,将新鲜水用量从15.2 L/m2降至11.3 L/m2,达到涂装行业清洁生产评价指标体系(2016版)中的Ⅰ级标准12 L/m2要求,处于国内领...     

中和方法对猪皮服装革质量的影响

通过组织学分析、物性检测等方法比较了猪皮服装革生产时用ＮＨ４ＨＣＯ３和中和复鞣剂中和对成革质量的影响。结果表明，用ＮＨ４ＨＣＯ３中和时，由于需要将革中和至较高的ｐＨ值（６．５左右）才能达到中和的目的，容易导致革纤维产生同部缺陷，从而降低成革质量。采用中和复鞣剂中和能明显减少同部缺陷，并使革纤维分散更均匀，成革的丰满弹性更好，松面率降低。本文选用萘磺酸型辅助性合成鞣剂ＮｅｏｓｙｎＢＳ２作为中和复鞣剂进行研究，确定了其最优使用方法。     

可控震源先进Ⅲ电控箱体常见故障分析及排除

在实际生产中，可控震源的故障很大一部分与其电控箱体有关，文章列举了几种因先进Ⅲ电控箱体而使I／O AHV—Ⅳ型可控震源出现的常见故障，分析了故障原因，并给出了排除方法。     

Frost formation on a bionic super‐hydrophobic surface under natural convection conditions

A bionic super‐hydrophobic surface has a multiple micro‐nano‐binary structure (MNBS) similar to the lotus leaf surface microstructure. This kind of surface has a contact angle of water greater than 150^° and a roll angle smaller than 5^°. In this paper, the frost deposition phenomena on a bionic super‐hydrophobic surface were observed. The surface has many micro bumps and its contact angle is 162^°. The formation of water droplets, the droplet freezing process, the formation of initial frost crystals and the frost layer structure on a cold bionic super‐hydrophobic surface under natural convection conditions were closely observed. The frost layer structure formed on the super‐hydrophobic surface shows remarkable differences to that on a plain copper surface: the structure is weaker, looser, thin, and easily removed and most importantly, it is of a very special pattern, a pattern similar to a chrysanthemum, a frost layer structure that has not been reported before to the best of the present authors knowledge. The experimental results also show that a super‐hydrophobic surface has a strong ability to restrain frost growth. The frost deposition on this bionic surface was delayed 55 minutes when compared with a plain copper surface under the conditions of a cold plate temperature of ?10.1^°C, air temperature of 18.4^°C, and relative humidity of 40%. A theoretical analysis was also presented to explain the observed phenomena. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(7): 412–420, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20216     

High-resolution cross-estimation channel modelling method and experimental results on broadband mobile communication in urban rich-scattering environment

For the IMT-advanced broadband mobile communication systems, an accurate broadband channel model is significant to the system design. However, the broadband channel impulse response (CIR) becomes sensitive to the complex propagation impacts of both specular path and diffuse dense path in a rich-scattering environment. We propose a cross-estimation (CE)-based channel modeling method by which the dense diffusion components can be identified independently and separated successfully from the overall CIR. As a result, the parameter estimation accuracy can be obviously improved, regardless of the complex diffusion impact in a rich scattering environment. Both theoretical derivation and experimental results are given to validate it based on the typical broadband channel measurement with 100 MHz bandwidth at 2.6 GHz in an urban hotspot scenario in Shanghai.     

放热型铁水预处理用高效复合脱硫剂的研究

为减少铁水炉外脱硫过程的温降,研制了一种含镁的复合脱硫剂。在150kg感应炉内模拟铁水罐喷吹脱硫的温度条件,试验了镁质脱硫剂的脱硫效果,并与取自生产现场的碳化钙基脱硫剂进行了脱硫效果与脱硫过程铁水温降的比较,为获得相同的脱硫效果,碳化钙基脱硫剂耗量为镁质脱硫剂的2倍、温降增加15℃。此外,探讨了铁水条件对镁利用率的影响。     

Study on Ti fiber reinforced TiAl<Subscript>3</Subscript> composite by infiltration-in situ reaction

This study is concerned with investigation of forming Ti fiber reinforced TiAl₃ composite by infiltration-in situ reaction. The as-cast material was obtained by pressing molten pure Al into a preform which was composed of Ti particles and Ti fibers. Based on the differential scanning calorimetry (DSC) result, in situ reaction samples were obtained by heating as-cast materials to 660, 950, and 1300 °C, and held for 1 h, respectively. The microstructure evolution of in situ reaction samples was analyzed by scanning electron microscope and Energy dispersive X-ray (EDX). In addition, the phase composition of products was inspected by X-ray diffraction (XRD). Experiment results show that TiAl₃ was formed initially, which was the unique product between Ti and Al. While at high temperature, products of Ti fibers and Al were complex, and Ti _x Al_1−x (0.25 < x < 0.75) compounds were formed around Ti fibers. Finally, TiAl₃ decomposed, and oxidation occurred. The mechanism of in situ reaction between Ti and Al in this system was discussed.     

Synthesis and characterization of a pH/temperature responsive glycine-mediated hydrogel for drug release

In this work, a pH/temperature responsive hydrogel (PMEA) from N-acryloylglycine methyl ester (NAGME), N-acryloylglycine ethyl ester (NAGEE), and acrylic acid (AAc) was synthesized by free radical polymerization. The swelling behaviors and drug release properties of hydrogels were systematically investigated at different temperature, pH, and AAc content. It was found that the hydrogel PMEA demonstrated pH and temperature responsive nature. The caffeine-release behaviors showed that only 49.1% caffeine was released from PMEA in pH 2.70 phosphate buffer solution (PBS) after 500 minutes, whereas more than 93.9% caffeine was gradually diffused into the medium in pH 7.49 PBS over the same time interval. In addition, the caffeine release was much higher at 37°C than that at 14°C in deionized water. As seen from the results, the PMEA seems to be a potential drug carrier with pH-temperature responsiveness.     

Effect of hammer peening on fatigue life of aluminum alloy 2A12-T4

In this study, a series of tests were conducted in aluminum alloy 2A12-T4 to investigate the effect of hammer peening process on the fatigue behavior of holes in specimens. The fracture surfaces of the specimens were observed by means of an optical microscope in order to disclose the mechanism of fatigue failure. The finite element method (FEM) was used to analyze the distribution of residual stress around the holes which were preliminarily treated with hammer peening. The results revealed that the crack of a hammer peened hole always initiated at the peened face. The fatigue life of these hammer peened holes significantly was prolonged five fold compared to non-hammer peened holes. Their fatigue life showed a positive correlation with the residual plastic strain which was induced by hammer peening process. The longest fatigue life was found in cases in which the residual plastic strain surrounded the whole bore of the hole but did not emerge at the fix face.