Self-healing Performance of Composite Coatings Prepared by Phosphating and Cerium Nitrate Post-sealing

The phosphated and cerium nitrate post-sealed galvanized steel was firstly scratched to expose zinc layer and then placed in neutral salt spray （NSS） chamber for different durations. The microstructure and compositions of the scratches were investigated using SEM and EDS. The phases of the corrosion products were examined through XRD. The self-healing mechanism of the composite coatings was discussed. The experimental results show that the composite coatings have an excellent corrosion resistance. The corrosion products increase with corrosion time and finally cover the whole scratch. They contain phosphorous, cerium, oxygen, chloride and zinc, and are fine needle and exceedingly compact. The composite coatings are favorable self-healing. During corrosion, the self-healing ions such as Ce3＋, Ce4＋, PO43-, Zn2＋ in the composite coatings were dissolved, migrated, recombined, and covered the exposed zinc, impeding zinc corrosion. The self-healing process of the scratches on the composite coatings can be divided into three stages, about 2 h, 4 h, and 24 h, respectively.

Investigation of Novel Short Fiber-like Polyaniline/Cerium Nitrate Composite

Polyaniline(PANI)/Ce(NO_3)_3 composite with short fiber-like shape was synthesized successfully in a poly(2-arcylamido-2-methylpropane sulfonic acid) aqueous solution. A comparison of SEM images found that short fiber-like composites can be obtained by controlling the dosage of Ce(NO_3)_3. The length and diameter of short fiber-like PANI/Ce(NO_3)_3 composite was about 630 and 200 nm, respectively. A special conjugated structure had formed via Ce^(3+) ions and –NH– group in the quinonoid ring of PANI, which was characterized by means of Fourier transform infrared(FTIR) spectroscopy, Ultraviolet-visible(UV-Vis) spectroscopy and X-ray photoelectron spectroscopy(XPS). Short fiber-like PANI/Ce(NO_3)_3 composite exhibited a high conductivity, a large capacitance and an enhanced anticorrosion property. Linear four-probe method confirmed that the electrical conductivity of composites was improved with the presence of Ce^(3+) ions. The corrosion potential of PANI/Ce(NO_3)_3 composite increased to-79 mV at 10 wt% of Ce(NO_3)_3. Meanwhile, the minimum density of corrosion current(1.4 μA/cm^2) was also achieved.

An expeditious synthesis of isoxazoline using cetyltrimethylammonium cerium nitrate:A phase transferring oxidative 1,3-dipolar cycloaddition

An expeditious and effective method for synthesis of isoxazoline from aldoximes and activated alkenes using cetyltrimethylammonium cerium nitrate at room temperature is described.Reaction was completed within short time period in high yields at room temperature.

Effects of Cerium Nitrate on Expression of CaM Ⅰ and PMCA Ca^( 2+ ) -ATPase mRNA in Rat Liver

The effect of cerium nitrate on expression of CaM Ⅰ and PMCA1b in rat liver was studied by means of reverse transcription-polymerase chain reaction (RT-PCR). The result shows that neither a high dose (50 mg·kg -1 ) nor a low dose (1 mg·kg -1 ) of cerium nitrate induces any alterations of expression of CaM Ⅰ and PMCA 1b mRNA after recurrent intraperitoneal injection of cerium nitrate, which suggests that effect of cerium nitrate on CaM and Ca 2+ -ATPase might be at posttranscription level.

Synthesis and Characterization of Cerium Tetraphenylporphyrin Nitrate and Molecular Recognition for NO

Cerium （III） tetraphenylporphyrin nitrate Ce（TPP）NO3 was synthesized by using meso- tetraphenylporphyrin （TPP） and Ce（NO3）.6H20 in mixture solution of CHC13 and C2HsOH （V：V=1：1）. The complex was characterized by UV-Vis, FT-IR, conventional fluorescence, MALDI-TOF-MS, and ^1H NMR spectral techniques. The structure of complex was proposed viaSpectral analyses, in which tetraphenylporphyrin was coordinated to a cerium ion in a tetradentate fashion, while one nitrate was coordinated to the same cerium ion. After bubbling NO to the solution of Ce（TPP）NO3 in CH2Cl2, spectral analyses suggested that Ce（TPP）NO3 could interact with NO to form a novel complex of Ce（TPP）（NO）NO3, and NO was coordinated to the center cerium ion. When nitrogen was poured into the Ce（TPP）（NO）（NO3） solution, the complex could be reduced to Ce（TPP）NO3.

Changes of Calpain mRNA Level in Rat Hepatocyte after Recurrent Intraperitoneal Administration of Ceium Nitrate

The effect of Ce(NO3)(3) on expression of calpain in rat hepatocyte was studied by means of reverse transcription-polymerase chain reaction (BT-PCR). The result shows that high dose of Ce(NO3)(3)(50 mg.kg(-1)) induces the increase of expression of calpain mRNA, but low dose of Ce(NO3)(3)(1 mg.kg(-1)) does not. Possible mechanism for this phenomenon was discussed.

铱(III)离子催化铈(IV)离子氧化四氢糠醇的动力学及机理

在酸性介质中用氧化还原滴定法研究了铈(IV)离子在痕量铱(III)离子催化作用下,于298￣313K区间氧化四氢糠醇(THFA)的反应动力学.结果表明,反应对铈(IV)离子为一级,对铱(III)离子也为一级,对四氢糠醇的表观反应级数为正分数.准一级速率常数kobs随[H+]增加而增大,而随[HSO-4]增加而减小.在氮气保护下,反应能引发丙烯腈聚合,说明在反应中有自由基产生.通过kobs与[HSO4-]的依赖关系,找到本反应体系的动力学活性物种是Ce(SO4)2,并计算出平衡常数,速控步骤的速率常数及相应的活化参数.

铬(III)离子催化铈(IV)离子氧化四氢糠醇的反应动力学及机理

在酸性介质中用氧化还原滴定法研究了铈(IV)离子在铬(III)离子催化作用下,于25～40℃区间氧化四氢糠醇的反应动力学.结果表明反应对铈(IV)和四氢糠醇均为一级.准一级速率常数kobs随催化剂[Cr(III)]增加而增大,亦随[H+]增加而增大,而随[HSO-4]增加而减小.在氮气保护下,反应不能引发丙烯酰胺聚合,说明在反应中没有自由基产生.提出了催化剂、底物和氧化剂间生成双核加合物的反应机理.通过kobs与HSO-4的依赖关系,并结合Ce(IV)在溶液中的平衡,找到了本反应体系的动力学活性物种是Ce(SO4)2.还计算出一些速率常数及相应的活化参数.

三水杨醛三乙基四胺合铈(III)金属配合物的合成及其与牛血清蛋白作用研究

本文利用水杨醛和三乙基四胺合成了三水杨醛三乙基四胺配体,将配体与Ce(NO3)3·6H2O反应合成了三水杨醛三乙基四胺合铈(III)金属配合物。使用熔点法、红外光谱法、荧光光谱法以及摩尔电导率法对合成的金属配合物结构进行了初步推测。用荧光光谱法对所合成的铈(III)金属配合物与牛血清蛋白的作用进行了研究,结果表明该金属配合物可与牛血清蛋白相互作用生成复合物,在0-2.6×10-5mol/L浓度范围内有两种淬灭方式:当浓度较小时(小于1.2×10-5mol/L)以静态淬灭为主,而当浓度大于1.2×10-5mol/L时则以动态淬灭为主。

Effect of organic component(tartrate) addition on cerium nitrate's ability to inhibit corrosion of mild steel in NaCl solution

Cerium tartrate(CeTar),produced in this study by precipitating cerium nitrate with potassium sodium tartrate(KNaTar),was examined as a corrosion inhibitor.Weight loss tests show inhibition efficiency of 71.7% with Ce(NO_(3))_(3) and 88.7% with CeTar inhibitor for one-month exposure to mild steel in 7 g/L NaCl solution.The inhibition efficiency drops to 28.6% with the fo rmer and remains around 8 7% with the latter inhibitor after six months of exposure.Similar results from electrochemical testing indicate that the inhibition efficiency decreases by adding cerium nitrate.Still,the cerium tartrate inhibitor demonstrates a nearly constant inhibition efficiency for up to 30 d,i.e.,≈90%.Electrochemical impedance spectroscopy(EIS) performed in these cases shows the following results:(ⅰ) with cerium nitrate,a film of iron and cerium oxide,which on prolonged exposure diminishes,and(ⅱ) with cerium tartrate,the formation of a bimetallic film(Fe-tartrate-Ce) and a mixture of cerium hydroxide and iro n oxide that protects steel for a longer duration.These inferences are based on the analyses of scanning electron microscopy/energydispersive X-ray analysis(SEM/EDAX),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron(XPS),and Raman spectroscopy results.

Cerium Chemical Conversion Coating on a Novel Mg-Li Alloy

A novel Mg-Li alloy was treated in a cerium nitrate solution and cerium chemical conversion coating was obtained on the alloy. Then the forming process, structure and corrosion resistance of the coating were investigated. The influential factors of cerium conversion coating were discussed through orthogonal experiments, and the optimum processing parameters were confirmed. XPS spectra displayed that the conversion coating consisted of cerium compounds, and the major component of the protective layer was a mixture of Ce （IV） oxide and Ce （IV） hydroxide. In addition, XRD pattern illustrated that there was crystalline CeO2 in the conversion coating. Analysis by SEM showed that the cerium conversion coating was uniform with a fiber-like morphology. The thickness of the conversion coating was 12 μm. The results of electrochemical potentiodynamic polarization and hydrogen evolution measurement indicated that the cerium conversion coating provided effective protection to the novel Mg-Li alloy.

稻田NO3-还原耦合As(III)氧化过程及微生物群落特征

以华南稻田土壤为研究对象通过构建微宇宙体系,研究了淹水稻田自养硝酸盐还原耦合As(III)氧化过程及其微生物群落结构组成.结果表明,NO3-的添加促进了稻田土壤中As(III)的氧化,在未添加NO3-的处理(Soil+As(III))以及灭菌处理(Sterilized soil+As(III)+NO3-)中As(III)未发生明显的氧化;在Soil+As(III)+NO3-处理中,NO3-有少量被还原,而在Soil+NO3-处理中,NO3-没有被还原.通过16S rRNA高通量分析在NO3-还原耦合As(III)氧化体系中微生物群落结构特征,在Soil+As(III)+NO3-处理中shannon指数相对较低为8.19,土壤微生物群落多样性降低,其中在门水平上主要优势菌群为变形菌门Proteobacteria(33%)、绿弯菌门Chloroflexi(11%)、浮霉菌门Planctomycetes(12%);在属水平上主要的优势菌属为Gemmatimonas(7.4%)以及少量的Singulisphaera、Thermomonas、Bacillus.NO3-的添加能够促进稻田土壤中自养As(III)氧化,并且影响着稻田土壤中微生物群落组成.

封闭处理对超声波辅助制备的锌系磷化膜耐蚀性的影响

在Q345钢磷化过程中引入超声波以改善锌系磷化膜表面平整度和致密性,为进一步提高超声波辅助制备的锌系磷化膜耐蚀性,分别采用油性封闭剂、硝酸铈溶液、硅酸钠溶液进行封闭处理。结果表明:硅酸钠溶液的封闭效果好于油性封闭剂和硝酸铈溶液,封闭后超声锌系磷化膜的物相组成为Zn_(3)(PO_(4))_(2)·4H_(2)O、Zn_(2)Fe(PO_(4))_(2)·4H_(2)O、ZnSiO_(3)和Na_(2)Si O_(3),并且呈现良好的致密性和耐蚀性,其耐硫酸铜点滴时间超过150 s,腐蚀电流密度低至3.20×10^(-6)A/cm^(2),较未封闭超声锌系磷化膜的腐蚀电流密度降低幅度接近一个数量级。在硅酸钠溶液封闭过程中发生腐蚀整平现象,同时生成ZnSiO_(3)并析出Na_(2)Si O_(3)起到填补孔隙的作用,使超声锌系磷化膜的致密性得到更大程度改善,从而显著增强抗腐蚀能力。

电化学系统内Feammox/NDFO耦合工艺脱氮效能和机理

针对目前Feammox/NDFO耦合工艺启动慢、脱氮效能不理想等缺陷,提出基于电化学原理强化Feammox/NDFO耦合工艺的策略.实验室内搭建生物电化学系统(BES)序批式厌氧反应器(B组),同时以不加电化学系统的普通厌氧反应器(A组)为对照组.A、B两组反应器共运行100d,分析了两反应器Feammox/NDFO耦合工艺启动过程中的脱氮效能、脱氮路径验证及种群结构组成,并探讨了BES系统Feammox/NDFO强化脱氮的机理.结果表明,实验组(B组)内NH_(4)^(+)-N去除率显著提高,第76d去除率趋于100%,TN去除率达65.83%;而对照组(A组)在第100d时,对NH_(4)^(+)-N和TN的去除率分别为50.22%和43.01%.脱氮路径验证实验结果表明,A、B组反应器内均有Feammox、NDFO、Anammox反应发生;并且B组反应器内反硝化速率明显大于A组.高通量测序结果表明,B组中铁循环脱氮功能菌中Desulfobacterota菌门的相对丰度较A组提高了2.34%;Thiobacillus和Denitratisoma丰度较A组分别提高了1.13%和0.87%.BES反应体系加速富集铁循环脱氮功能菌群,并可通过BES电极进行胞外电子转移,从而达到增强脱氮效能.

硝酸铈与脱落酸处理对紫花苜蓿种子萌发和幼苗生理特性的影响

为研究稀土铈(Ce)与外源脱落酸(ABA)处理对紫花苜蓿种子萌发和幼苗生理特性的影响,采用浓度分别为5、10、20μmol·L^(-1)的硝酸铈、ABA及硝酸铈和ABA(1∶1)的混合溶液处理苜蓿种子进行发芽试验,探究其对种子的萌发、生长,幼苗的叶绿素含量、抗氧化酶活性和渗透调节物质含量等指标的影响。结果表明:5~10μmol·L^(-1)硝酸铈处理刺激了紫花苜蓿种子的萌发,并增大了根粗(5~20μmol·L^(-1));而ABA(5~20μmol·L^(-1))抑制了种子萌发和幼苗生长,且与硝酸铈混合处理解除了硝酸铈对根粗的膨大作用。硝酸铈可以缓解ABA对叶绿素含量的降低,并降低幼苗叶抗氧化酶活性,而Ce与ABA混合处理可显著提高紫花苜蓿幼苗的抗氧化酶活性。因此,硝酸铈处理对紫花苜蓿萌发及生长有一定的积极作用;硝酸铈与ABA混合处理时,ABA在调节紫花苜蓿种子萌发和幼苗生长过程以及生理特性中发挥主导作用,硝酸铈+ABA处理的幼苗高抗氧化活性,表明幼苗受到胁迫。研究结果为稀土铈和ABA对紫花苜蓿萌发期的影响提供了参考。

Effects of cerium nitrate on the growth and physiological characteristics in Cyclocarya paliurus seedlings

Field studies were conducted to examine the effects of cerium on the growth and physiological characteristics of Cyclocarya paliurus seedlings by spraying the foliage with different concentrations of cerium nitrate. Optimal concentrations of cerium nitrate improved the relative growth yield of seedling height and stems and the soluble protein and sugar content of the leaves. Cerium nitrate also increased the concentration of secondary metabolites including triterpenoids, quercetin and kaempferol, mineral elements K, P, Mg, Mn, Fe and Cu, and the activities of superoxide dismutase （SOD）, peroxidase （POX）, and phenylalanine ammonia-lyase （PAL） in the leaves. The effects of cerium nitrate on these indices were dose dependent. A concentration of 0.20 mmol/L was optimal to promote the relative growth yield of seedling height, contents of soluble sugar, kaempferol, K, P, Cu, and activities of PAL, SOD, and POX, significantly increased by 54.61%, 14.71%, 55.19%, 105.2%, 74.5%, 133.3%, 80.48%, 25.35% and 22.54%, respectively, as compared with the control. However, the maximal increase in relative growth yield of stems, contents of triterpenoid, quercetin, Mg, Mn, and Fe was attained at 1.00 mmol/L treatment, which significantly increased by 87.00%, 80.56%, 452.44%, 93.2%, 29.4%, and 133.9%, respectively, compared with control check （CK）. Correlation analysis revealed positive relationships between activities of PAL, SOD and contents of triterpenoid, quercetin and kaempferol within a certain concentration range of cerium nitrate. These resuits suggested that an appropriate concentration of cerium not only was effective in the improvement of physiological function of C. paliurus, but also increased seedling resistance. Moreover, it stimulated the synthesis of medicinal components in leaves.

基于硝酸铈调控红法夫酵母产虾青素的发酵优化

虾青素因其超强的抗氧化、抗癌等活性以及优良的着色能力,在食品、医药、饲料及化妆品等行业中具有广泛的应用前景。红法夫酵母展现出了生产天然虾青素的巨大潜力,而其代谢调控和发酵优化策略对虾青素的生产有着显著影响。文章以硝酸铈为化学诱导子对红法夫酵母产虾青素进行调控,并优化了培养基和发酵操作方式。结果表明,当摇瓶条件下硝酸铈在第12时添加的质量浓度为50 mg/L时,虾青素产量与初始对照相比提高了34.92%,且硝酸铈介导的红法夫酵母胞内,活性氧质量分数及虾青素合成相关基因crtE、crtI、c rtYB和ast的基因表达均显著上调。同时,基于硝酸铈的调控作用,文章采用响应面方法对发酵培养基的3个主要成分葡萄糖、酵母浸粉、硝酸铈进行了优化,并发现当各元素质量浓度为葡萄糖24.1 g/L、酵母浸粉1.4 g/L、硝酸铈45.9 mg/L时,虾青素含量为1.244 mg/L,比初始对照提高了50.11%。此外,还在5 L机械搅拌发酵罐中采用了分批-补料发酵操作方式。实验显示,虾青素产量高达13.28 mg/L,比分批发酵和初始对照分别提高了3.67和16.54倍。

Dissociation of outer membrane for Escherichia coli cell caused by cerium nitrate

The biological effect of cerium nitrate on the outer membrane(OM) of Escherichia coli(E.coli) cell was studied,and the antim-icrobial mechanism of rare earth elements was explored.The antimicrobial effect of cerium nitrate on E.coli cell was valued by plate count method,and the morphology change of E.coli cell was observed with scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results showed that the E.coli cell suspension was flocculated when the concentration of Ce(NO3)3?6H2O...

Cerium(Ⅳ) ammonium nitrate(CAN) initiated O-alkylation of oximes with N-vinyl lactams

O-Alkylation of oximes with N-vinylpyrrolidin-2-one or N-methyl-N-vinylacetamide was efficiently initiated by a catalytic amount of cerium（Ⅳ） ammonium nitrate（CAN）,giving the corresponding oxime ether derivatives in good yield.

基于DoE实验设计的硝酸铈溶液雾化特性研究

为满足喷雾热分解法制备氧化铈颗粒需求,使用两相流空气辅助雾化喷嘴,对不同浓度的硝酸铈溶液雾化特性进行了实验研究,并使用响应曲面法对硝酸铈溶液喷雾的雾化颗粒度SMD实验数据进行了定量分析,得到了雾化颗粒度SMD与溶液物理性质及雾化环境参数之间的定量关系。本实验中溶液质量浓度为0.334~0.462、溶液体积流量为0.05 m^(3)/h和0.12 m^(3)/h、雾化空气压力为0.2~0.5 MPa。根据对获得的定量关系式分析可知,对硝酸铈溶液雾化颗粒度SMD影响最显著的因素是溶液浓度,其次是雾化空气压力,溶液体积流量对雾化颗粒度SMD的影响较小;雾化颗粒度均随雾化空气压力的升高而减小,雾化空气压力对粘性较小溶液的影响更加显著。