混凝土盐结晶破坏的研究

以混凝土剥落量、膨胀率和强度损失率为评价指标,研究了干湿循环条件下Na2SO4和NaCl盐结晶对混凝土的破坏,并与在Na2SO4和NaCl盐溶液中浸泡的混凝土的化学侵蚀破坏结果进行对比.研究表明,混凝土在干湿循环条件下发生的盐结晶破坏明显比化学侵蚀破坏严重;盐结晶产生的混凝土膨胀和剥蚀破坏随着盐浓度和干湿循环次数的增加明显增大,且超过一定干湿循环次数后,混凝土经干燥后非但不收缩,反而继续膨胀;盐晶体刚开始主要起密实与增强作用,只有当盐晶体量超过一定值后,才会引起混凝土发生膨胀和破坏;引气可以显著降低和延缓混凝土的盐结晶破坏.     

Corrosion of Artificial Aged Magnesium Alloy AZ80 in 3.5 wt pct NaCl Solutions

The corrosion morphologies of aged magnesium alloy AZ80 were investigated by immersion corrosion tests, scanning electron microscopy （SEM）, electrochemical measurement. The T5 heat treatment was carried out in a vacuum furnace, holding for 16 h at 177℃, and then cooling in air. The results showed intergranular corrosion （IGC） occurred as an aged AZ80 sample was immersed in 3.5 wt pct NaCI aqueous solution for 1 h and the narrow path attack progressed predominantly along the bulk β phase in the grain boundaries or took place in the eutectic areas. IGC was attributed to the network distribution of β phase along the grain boundaries, the depleted aluminium in the precipitation areas and the breakdown potential.     

镁合金阳极氧化膜在NaCl溶液中的腐蚀行为

利用盐水浸泡实验研究了AZ91D镁合金阳极氧化膜层在3．5％NaCl溶液中的腐蚀行为。结果表明：AZ91D镁合金阳极氧化膜层不论封闭与否,在中性NaCl溶液中浸泡出现第一个腐蚀点后,膜层表面均很少再出现新的腐蚀点,而是原有的腐蚀点向纵、横两个方向扩展形成腐蚀坑,表面呈“树枝”状腐蚀形貌;浸泡溶液的pH值对阳极氧化膜层的耐蚀性影响很大,酸性溶液中的腐蚀速率明显大于中、碱性溶液的;随浸泡溶液温度的升高阳极氧化膜层的腐蚀速率加快。据此,提出了AZ91D镁合金阳极氧化膜层在NaCl溶液中腐蚀过程的模型。     

High intensity ultrasound effects on meat brining

Pork loin (longissimus dorsi) samples of two different geometries, cylinders and slabs, were immersed in saturated NaCl brine for 45 min under different conditions: without brine agitation (STAT), with brine agitation (AG) and with ultrasound application (US) at eight levels of ultrasonic intensity. Moisture content change and NaCl gain were considered in order to evaluate the difference in the brining treatments. No significant differences were found in moisture and NaCl content of samples treated under STAT conditions and AG conditions, while the influence of ultrasound on the mass transfer process during meat brining depended on the intensity applied. There was an ultrasonic intensity threshold above which the influence of ultrasound appeared. At the highest level of intensity studied, the water content of samples was significantly higher than the initial water content of meat. As regards NaCl transfer, once above the intensity threshold, the increase in the NaCl content was proportional to the applied ultrasonic intensity. Not statistically significant differences were found for sample geometry.     

1Cr18Ni9Ti不锈钢在含NH4+的NaCl水溶液中应力腐蚀开裂研究

研究了退火态 1Cr18Ni9Ti不锈钢在 78± 5℃的纯NaCl和NH4Cl溶液、NH4Cl +NaCl混合溶液中的应力腐蚀性能。结果表明 ,在 2 2 %NaCl溶液中试样经 10 0 0h试验不发生应力腐蚀开裂 ,而浸在 3%NH4Cl+17%NaCl、5 %NH4Cl+10 %NaCl、5 %NH4Cl+17%NaCl、5 %NH4Cl+2 5 %NaCl 4种混合溶液的试样 ,经过小于 10 0 0h的试验就产生应力腐蚀裂纹或断裂 ,即NH+ 4 促进了 1Cr18Ni9Ti钢在NaCl溶液中的应力腐蚀开裂。根据扫描断口形貌和裂纹扩展途径的金相观察 ,还探讨了在混合溶液中的应力腐蚀机制。     

Ni/Al2O3复合镀层在800℃ NaCl盐膜下的腐蚀

考察了表面涂有NaCl盐膜的不同Al2O3含量的Ni／Al2O3复合镀层在800℃空气中的耐蚀性。结果表明：在该环境下镀层均发生严重腐蚀,形成厚且疏松的表面腐蚀层;镀层的耐蚀性与Al2O3的含量直接有关,随着Al2O3含量的增多,镀层的耐蚀性提高。     

可降解凝胶蓄冷剂的制备及性能分析

对温控包装中一种可降解凝胶蓄冷剂的制备方法进行了介绍,蓄冷剂以NaCl溶液作为主储能材料,淀粉系吸水树脂作为基材,通过添加成核剂来降低过冷度。实验结果表明,蓄冷剂的相变温度和相变潜热随着NaCl溶液浓度的增大而降低,筛选出的最佳成核剂有效降低了蓄冷剂的过冷度。研究工作验证了蓄冷剂的可生物降解性能,给出了适用于5～-10℃温控包装的凝胶蓄冷剂配方及其热物性参数。     

基于智能感官和气相色谱-质谱联用技术研究食盐添加量对风干肠风味特征的影响

将智能感官技术(电子舌和电子鼻)与气相色谱-质谱仪相结合研究食盐添加量(2.50％、2.00％、1.75％和1.50％)对风干肠风味特征的影响.结果表明,随食盐添加量的减少,水分含量、水分活度和乳酸菌总数逐渐升高,pH值逐渐下降(P＜0.05).电子舌和电子鼻结果表明,食盐添加量为2.00％和1.75％的处理组滋味和气...     

Minimising non-selective defects in ultrathin reduced graphene oxide membranes with graphene quantum dots for enhanced water and NaCl separation

Reduced graphene oxide (rGO) membranes have been intensively evaluated for desalination and ionic sieving applications,benefiting from their stable and well-confined interlayer channels.However,rGO membranes generally suffer from low permeability due to the high transport resistance resulting from the narrowed two-dimensional (2D) channels.Although high permeability can be realized by reducing membrane thickness,membrane selectivity normally declines because of the formation of non-selective defects,in particular pinholes.In this study,we demonstrate that the non-selective defects in ultrathin rGO membranes can be effectively minimised by a facile posttreatment via surface-deposition of graphene quantum dots (GQDs).The resultant GQDs/rGO membranes obtained a good trade-off between water permeance (14 L·m-2·h-1·MPa-1) and NaCl rejection (91％).This work provides new insights into the design of high quality ultrathin 2D laminar membranes for desalination,molecular/ionic sieving and other separation applications.