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Investigating local corrosion processes of magnesium alloys with scanning probe electrochemical techniques: A review

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Journal of Magnesium and Alloys 2022年第11期10卷 2997-3030页

作者： Mara Cristina Lopes de Oliveira Rejane Maria Pereira da Silva Ricardo M.Souto Renato Altobelli Antunes Federal University of ABC Center for EngineeringModeling and Applied Social SciencesAv.Dos Estados500109210-580Santo AndréSP Brazil Instituto de Pesquisas Energéticas e Nucleares IPEN/CNENAv.Prof.Lineu Prestes2242São PauloBrazil Institute of Material Science and Nanotechnology University of La LagunaP.O.Box 456La LagunaTenerife 38200Spain

The study of corrosion of magnesium and its alloys has emerged a hot topic in the applications of lightweight structural materials. The inherently high electrochemical activity of bare magnesium surfaces still lacks a convincing mechanism to describe the observed experimental characteristics, and it has prompted the development of various types of protective coatings with the aim of slowing metal dissolution. In recent years, new instruments and techniques have been developed to study with spatial resolution the local corrosion processes that occur in metallic materials in general, and for magnesium and its alloys in particular, both for bare surfaces and coated. Scanning microelectrochemical techniques, such as local electrochemical impedance spectroscopy(LEIS), scanning electrochemical microscopy(SECM), scanning vibrating electrode technique(SVET), scanning ion-selective electrode technique(siet) and scanning Kelvin probe(SKP) can provide information about the local electrochemical activity of metallic surfaces. In the present work, the applications of these techniques in corrosion studies of magnesium and its alloys are reviewed. Assessment of corrosion mechanisms, barrier properties of conventional coatings and active corrosion behavior of self-healing coatings are examined. Limitations and future developments in this area are discussed.

关键词： Magnesium alloys LEIS SECM SVET siet SKP

The positive function of selenium supplementation on reducing nitrate accumulation in hydroponic lettuce(Lactuca sativa L.)

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Journal of Integrative Agriculture 2018年第4期17卷 837-846页

作者： LEI Bo BIAN Zhong-hua YANG Qi-chang WANG Jun CHENG Rui-feng LI Kun LIU Wen-ke ZHANG Yi FANG Hui TONG Yun-xin Key Laboratory of Energy Conservation and Waste Treatment of Agricultural Structures Ministry of Agriculture/Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences Nottingham Trent University Brackenhurst Campus

High nitrate(NO3-) in vegetables, especially in leaf vegetables poses threaten to human health. Selenium(Se) is an important element for maintaining human health, and exogenous Se application during vegetable and crop production is an effective way to prevent Se deficiency in human bodies. Exogenous Se shows positive function on plant growth and nutrition uptake under abiotic and/or biotic stresses. However, the influence of exogenous Se on NO3-accumulation in hydroponic vegetables is still not clear. In the present study, hydroponic lettuce plants were subjected to six different concentrations(0, 0.1, 0.5, 5, 10 and 50 μmol L–1) of Se as Na2 Se O3. The effects of Se on NO3-content, plant growth, and photosynthetic capacity of lettuce(Lactuca sativa L.) were investigated. The results showed that exogenous Se positively decreased NO3-content and this effect was concentration-dependent. The lowest NO3-content was obtained under 0.5 μmol L–1 Se treatment. The application of Se enhanced photosynthetic capacity by increasing the photosynthesis rate(Pn), stomatal conductance(Cs) and the transpiration efficiency(Tr) of lettuce. The transportation and assimilation of NO3-and activities of nitrogen metabolism enzymes in lettuce were also analysed. The NO3-efflux in the lettuce roots was markedly increased, but the efflux of NO3-from the root to the shoot was decreased after treated with exogenous Se. Moreover, Se application stimulated NO3-assimilation by enhancing nitrate reductase(NR), nitrite reductase(Ni R), glutamine synthetase(GS) and glutamate synthase enzyme(GOGAT) activities. These results provide direct evidence that exogenous Se shows positive function on decreasing NO3-accumulation via regulating the transport and enhancing activities of nitrogen metabolism enzyme in lettuce. We suggested that 0.5 μmol L–1 Se can be used to reduce NO3-content and increase hydroponic lettuce yield.

关键词： selenium NO_3^- nitrogen metabolism enzyme siet photosynthetic performance lettuce

NaCl-Induced Changes of Ion Fluxes in Roots of Transgenic Bacillus thuringiensis (Bt) Cotton (Gossypium hirsutum L.)

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Journal of Integrative Agriculture 2013年第3期12卷 436-444页

作者： LI Mao-ying LI Fang-jun YUE Yue-sen TIAN Xiao-li LI Zhao-hu DUAN Liu-sheng State Key Laboratory of Plant Physiology and Biochemistry Ministry of Education/Engineering Research Center of Plant Growth Regulator Ministry of Education/College of Agronomy and Biotechnology China Agricultural University

Bacillus thuringiensis （Bt） cotton is grown worldwide, including in saline soils, but the effect of salinity on ion fluxes of Bt cotton remains unknown. Responses of two transgenic Bt cotton genotypes （SGK321 and 29317） and their corresponding receptors, Shiyuan 321 （SY321） and Jihe 321 （J321）, to 150 mmol L-1 NaCl stress were studied in a growth chamber. The root dry weight of SGK321 and 29317 under NaCl treatment was decreased by 30 and 31%, respectively. However, their corresponding receptor cultivars SY321 and J321 were less affected （19 and 24%, respectively）. The root length and surface area of the Bt cultivars were significantly decreased relative to their receptors under salt stress. NaCl treatment significantly increased CrylAc mRNA transcript levels in SGK321 and 29317 but did not affect Bt protein content in leaves or roots of either cultivar at 1 and 7 d after NaCl treatment. Fluxes of Na^＋, K^＋, and H^＋ in roots were investigated using the scanning ion-selective electrode technique. Both mean K^＋ efflux rate and transient K^＋ efflux of the Bt cultivars increased four-fold compared to their corresponding receptors when exposed to salinity stress. There were no significant differences in Na^＋ efflux between Bt and non-Bt cottons. Furthermore, the Na^＋ contents in roots and leaves of all genotypes dramatically increased under salt stress, whereas K^＋ contents decreased. Our results suggested that Bt cotton cultivars are more sensitive to salt stress than their receptor genotypes.

关键词： transgenic Bt cotton salinity stress toxin protein siet K^＋ flux

The calibration model in potassium ion flux non-invasive measurement of plants in vivo in situ

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Information Processing in Agriculture 2016年第2期3卷 76-82页

作者： Lin Xue Dong-jie Zhao Zi-yang Wang Xiao-dong Wang Cheng Wang Lan Huang Zhong-yi Wang College of Information and Electrical Engineering China Agricultural UniversityBeijing 100083China College of Information Technology Beijing Union UniversityBeijing 100101China Modern Precision Agriculture System Integration Research Key Laboratory of Ministry of Education Beijing 100083China Key Laboratory of Agricultural Information Acquisition Technology(Beijing) Ministry of AgricultureBeijing 100083China National Engineering Research Center for Information Technology in Agriculture Beijing 100097China

siet(Self-referencing Ion Electrode Technique)provides a novel electrophysiological tool which can non-invasively measure the dynamic influxes and effluxes of ions caused by the diffusion along the concentration gradients in vivo.However,in this technique ion fluxes are converted to voltage signals using an ion selective microelectrode at a small amplitude of lV,which is easy to be interfered by the ambient noise.Hence,effective solutions to the suppression of noise and calibration of ion flux measurement system are very important for this method.A K^+-selective microelectrode was constructed using liquid ion exchangers(LIX)to investigate ion transport over plant tissue.A standard concentration gradient which simulates plant living cells was produced by an electrode with a certain tip diameter,filled with a solution containing a known K+concentration in 100 mmol/L.An ion diffusion simulation model was established.This model evaluated the performance of ion flux measurement system in accuracy and reliability by comparing the consistency of the measured value and the predicted curve.K^+fluxes were measured within 25 min at each measuring point of distance 10,20,30,40,50,80,and 100 lm from the K+source,respectively.It can be seen that the K^+fluxes changes little,which indicates that ion flux measurement system has a reliable stability.The study provides a theoretical basis for a new non-invasive ion flux measurement method creation and a new sensors design.

关键词： siet Plant K^+flux Calibration In situ

非损伤性扫描离子选择电极技术及其在高等植物研究中的应用

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自然科学进展 2006年第3期16卷 262-266页

作者：印莉萍上官宇许越首都师范大学生命科学学院北京100037 Younger USA Company

各种分子和离子进出细胞的过程对于维持植物体自身的活性至关重要．非损伤性扫描离子选择电极技术(scanning ion-selective electrode technique,siet)在不接触被测生物样品,即在保持被测生物样品完整和近乎实际生理环境的状态下,获得... 详细信息

各种分子和离子进出细胞的过程对于维持植物体自身的活性至关重要．非损伤性扫描离子选择电极技术(scanning ion-selective electrode technique,siet)在不接触被测生物样品,即在保持被测生物样品完整和近乎实际生理环境的状态下,获得进出样品的各种分子和离子的信息．该技术不仅能够测量离子及分子静止状态下的绝对浓度,而且还可以测量它们进出生物样品的运动速率及运动方向．siet可以围绕被测的单个或多个细胞、组织甚至器官进行灵活、方便而准确的立体测量并获得被测物体周围的离子或分子的三维立体数据．目前,siet不但可以分别测量 H+,ca2+,K+,Al3+,Cd2+,Cl-和O2,CO2,NO及温度等参数,而且可以同时采集多种离子及参数,为获得生物样品内外分子或离子运动的有关信息提供了良好的实验平台．

关键词：非损伤性电生理技术离子选择性电极离子跨膜转运 siet

铝合金2024-T3及其防护涂层的微区腐蚀研究

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铝合金2024-T3及其防护涂层的微区腐蚀研究

作者：田振煌东北大学

学位级别：硕士

铝合金2024-T3作为一种硬铝,由于其优点独特,主要用作飞机的多种结构件,已成为使用最广的航空铝合金。为提高铝合金的强度,通常通过一定的方式(如时效热处理)有意识地在合金中引入第二相,但含Cu、Fe、Mn、Mg等元素的第二相在提高机械强... 详细信息

铝合金2024-T3作为一种硬铝,由于其优点独特,主要用作飞机的多种结构件,已成为使用最广的航空铝合金。为提高铝合金的强度,通常通过一定的方式(如时效热处理)有意识地在合金中引入第二相,但含Cu、Fe、Mn、Mg等元素的第二相在提高机械强度的同时,却降低了铝合金的耐腐蚀性能。铝合金2024-T3的主要防护措施是涂层防护,其中铬酸盐涂层的应用历史最久。然而,现在涂层防护中最有效的腐蚀抑制剂铬酸盐已经由于其致癌性被禁止使用,无铬涂层的开发和性能研究成为航空铝合金防腐研究的热点方向。自从上世纪70年代微区电化学测试技术被引入到腐蚀与防护领域以来,微区电化学理论和测试技术都得到了快速的发展。近几年来,扫描离子选择电极技术(siet)和扫描振动电极技术(SVET)在腐蚀与防护领域已作为重要的测试方法被广泛应用。因此,将微区电化学技术与铝合金2024-T3及其无铬涂层的腐蚀与防护研究结合起来具有独特的优势。本研究以金属间化合物0相(Al2Cu)和Al3Fe相与铝丝组成耦合电极模拟铝合金的晶间腐蚀,再利用铝合金2024-T3辅助研究其晶间腐蚀的机理,最后借助扫描离子选择电极技术(siet)、扫描振动电极技术(SVET)、扫描电镜(SEM)和能谱分析(EDS)等表征手段明确晶间腐蚀的机理。结果表明,0相和A13Fe相在晶间腐蚀中作为阴极,铝丝则为阳极;铝合金2024-T3的S相(Al2CuMg)比a相(Al)先溶解。腐蚀抑制剂对减缓铝合金腐蚀具有重要作用,为了考察8-羟基喹啉腐蚀抑制剂的效果,研究了其饱和NaCl水溶液对金属间化合物0相和Al3Fe与铝丝组成的电极体系的影响,研究了其饱和NaCl水溶液对铝合金2024-T3裸基材腐蚀的抑制效果。结果表明,8-羟基喹啉腐蚀抑制剂在上述研究中起到了明显的腐蚀抑制效果。最后将8-羟基喹啉作为无铬腐蚀抑制剂添加到铝合金2024-T3的防护涂层(自组装纳米涂层),在中性NaCl水溶液环境下,采用电化学阻抗、SVET和SEM等表征手段研究自组装纳米涂层的性能。结果表明添加8-羟基喹啉的涂层能够有效降低铝合金2024-T3的腐蚀速率,从而起到保护铝合金的效果。

关键词：铝合金2024-T3 siet SVET 腐蚀抑制剂自组装纳米涂层

利用滩涂野大豆提高栽培大豆耐盐性的生理和细胞学研究

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利用滩涂野大豆提高栽培大豆耐盐性的生理和细胞学研究

作者：张晓可南京农业大学

学位级别：硕士

本文以栽培大豆和滩涂野大豆杂交组合(N23674×BB52)亲本及其经逐代耐盐性筛选而获得的杂交后代4076(F5)幼苗为材料,首先用大豆的根和叶片为材料,探究大豆原生质体分离的方法、纯化方法及其影响因素;然后用140mmol·L-1 NaCl溶液处理0、... 详细信息

本文以栽培大豆和滩涂野大豆杂交组合(N23674×BB52)亲本及其经逐代耐盐性筛选而获得的杂交后代4076(F5)幼苗为材料,首先用大豆的根和叶片为材料,探究大豆原生质体分离的方法、纯化方法及其影响因素;然后用140mmol·L-1 NaCl溶液处理0、2、4、6d,从干物质积累量、叶面积、根系吸收面积、膜透性与渗透调节物质以及离子含量变化等生理方面,并采用siet(非损伤微测技术)从细胞水平对其耐盐能力或特性进行了比较研究。主要结果如下：适宜大豆根和叶片原生质体分离的酶种类、浓度分别为CPW-13M{CPW(细胞清洗液)+13%(W／V)甘露醇}+3%纤维素酶(cellulose R-10)+1.1%果胶酶(macerozymeR-10)+1.0%半纤维素酶(hemicellulase)和0.15%CaCl2.2H20+9%甘露醇+1%cellulase R-10+0.20% pectolaseY-23, pH 5.8,酶解温度为28℃。在根酶解时间为16 h时,原生质体产量可高达1.46×105个／g FW,活力达57.8%;叶片酶解时间为4 h时,原生质体产量可高达1.74×106个／g FW,活力达70.3%。对于根而言,从产量和活力两方面考虑,其原生质体用23%蔗糖和CPW-18M混合后的下沉法纯化效果较好,而叶片用25%蔗糖的上浮法纯化效果较好。用含140mmol·L-1 NaCl的1/2 Hoagland溶液处理0、2、4、6d后,供试3材料发芽期和幼苗根、叶伤害程度都为N23674>4076>BB52;根系吸收面积和根系活力大小顺序为4076>BB52>N23674。随着盐胁迫时间的增加,供试3材料根、叶片和叶绿体中心含量下降,Na+、Cl-含量和Na+／K+增加,BB52和4076体内Na+、Cl-含量增加或K+含量减少幅度小于N23674,但Na+／K+情况相反。与Na+相比,BB52和4076根系对K+的吸收和向叶片运输的选择性(SK,Na)较强。3材料的叶绿素含量、叶片净光合速率和PS IⅡ最大光化学效率都逐渐下降,其中N23674降幅较大。盐胁迫下大豆叶绿体中Na+、Cl"含量和Na+／K+与叶片净光合速率呈极显著负相关,N23674尤为明显。在140mM NaCl胁迫下,与栽培大豆N23674相比,野大豆BB52种群和杂交后代4076无论在根组织还是在根和叶片原生质体中都表现出更强的对Na+和Cl-的外排能力以及对H+、K+、Ca2+相对稳定的内流能力,在原生质体中尤为明显,这与其较强的耐盐性是一致的。综上所述,通过栽培和滩涂野大豆的杂交和多代筛选,其后代4076(F5)的耐盐性得以明显提高。

关键词：野生大豆栽培大豆杂交后代耐盐性生理指标 siet 原生质

卷边桩菇（Paxillus）抗盐菌株MAJ和NAU离子流和耐盐性比较研究

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卷边桩菇（Paxillus）抗盐菌株MAJ和NAU离子流和耐盐性比较研究

作者：包斯琴北京林业大学

学位级别：硕士

土壤盐渍化和干旱是限制我国农林业发展的主要问题,探索切实可行的生物技术途径增强作物和林木的抗旱耐盐性是解决该问题的有效途径。近来的研究表明,菌根（真菌与植物根系共生所形成）可以显著提高植物的抗逆性。目前,国内外的研究者... 详细信息

土壤盐渍化和干旱是限制我国农林业发展的主要问题,探索切实可行的生物技术途径增强作物和林木的抗旱耐盐性是解决该问题的有效途径。近来的研究表明,菌根（真菌与植物根系共生所形成）可以显著提高植物的抗逆性。目前,国内外的研究者们对外生菌根提高植物的抗旱耐盐机制进行了一些研究,然而,关于外生菌根（Ectomycorrhiza）如何改善宿主植物离子平衡及提高树木耐盐机制方面的系统研究较少。因此,本研究主要通过研究抗盐真菌的耐盐机理,以期揭示菌根的耐盐机制。利用非损伤性扫描离子选择电极技术（siet）测定盐胁迫下,卷边桩菇（Paxillus involutus）的两种菌株MAJ和NAU的Na+、H+、K+和Ca2+离子的动态变化。目的通过研究两种菌株的耐盐性,有助于进一步研究菌根植物的耐盐机理。盐胁迫下,菌丝保持K+/Na+平衡的能力很强。在短期盐处理（50 mM NaCl处理24 h）和长期盐处理（50 mM NaCl处理7 d）下,两种菌株Na+离子外流明显增加,尤以NAU菌丝更加明显。Paxillus Involutus菌丝的抑制剂的敏感性研究显示,两种菌株Na+离子外排源于Na+/H‘逆向转运。在瞬时盐处理下,两种菌株都有很强的减少K+离子外流的能力。在非盐胁迫下,两种菌株显示稳定的Ca2+离子内流。因此推断,在盐胁迫下,Paxillus involutus真菌所富含的Ca2+有助于宿根共生体通过增强Na+外排和减缓K+离子流失来协助宿主植物保持离子平衡的。

关键词： Paxillus involutus MAJ NAU 耐盐性 siet 离子流

NaCl胁迫下转基因抗虫棉及其受体材料根系离子流变化（英文）

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NaCl胁迫下转基因抗虫棉及其受体材料根系离子流变化（英文）