抗菌处理含铜铁素体不锈钢的耐微生物腐蚀性能

采用电化学测试技术及微生物学方法, 研究了抗菌处理含铜铁素体不锈钢在含有培养基的异养菌溶液中的耐蚀性能. 结果表明, 不锈钢的腐蚀电位随异养菌的新陈代谢呈现规律性变化, 抗菌处理使不锈钢在菌液中钝化膜的稳定性得到改善, 点蚀敏感性降低; 抗菌不锈钢表面弥散分布的ε-Cu析出相的杀菌作用, 降低了异养菌的活性, 减缓了异养菌对抗菌不锈钢的腐蚀, 提高了抗菌不锈钢耐微生物腐蚀性能.     

铈掺杂氧化锌（1000）晶面的SO2吸附性能研究

基于密度泛函理论,仿真建立了铈（Ce）掺杂氧化锌ZnO（1000）晶面的SO₂分子吸附模型,并计算了其吸附能、电荷转移量、吸附距离、电子态密度及脱附时间以探究吸附及脱附特性.计算得到Ce掺杂ZnO（1000）晶面的SO₂吸附结构有较大的吸附能（-1.66 eV）,且在温度为398 K时,该体系具有符合实际传感检测过程的脱附时间（1.433×10³ s）.结果表明Ce掺杂ZnO（1000）晶面对SO₂分子显示出优异的吸脱附性能.     

稀土氧化物前驱体的合成及其对YAG:Ce荧光粉影响的研究

分别用草酸和碳酸氢铵为沉淀剂通过沉淀法制备氧化钇及钇铈复合氧化物.并以其为原料,在高温下合成YAG:Ce黄色荧光粉.用XRD、SEM、粒度测试仪、光谱分析仪等表征了氧化物前驱体和YAG:Ce.SEM和比表面测试结果表明,碳酸氢铵沉淀法制备的氧化钇或钇铈复合氧化物的一次粒径约100nm,形貌规则,比表面积高.用该钇铈复合氧化物合成的YAG:Ce具有发光强度高、形貌规则、粒度小等优点.     

金属改性SBA-15应用于乙醇水蒸气重整制氢的研究

采用水热法将Ce金属引入SBA-15骨架,合成一系列Ce-SBA-15（Si/Ce=40,20,10）载体,再通过浸渍法制得Co/Ce-SBA-15催化剂.利用XRD、UV-Vis、FT-IR、H₂-TPR、N₂吸附-脱附等手段对催化剂进行表征,并用于乙醇水蒸汽重整制氢反应（ESR）,考察载体骨架中Ce金属对催化剂结构和性能的影响.结果表明,水热法制备可使得Ce离子进入到SBA-15分子筛骨架,合成的载体仍保持SBA-15特有的介孔结构.与Co/SBA-15催化剂相比,基于铈的储放氧功能,Ce的加入提高了活性金属分散度,降低了反应积碳的生成,改善了催化剂稳定性.适量铈与钴的协同作用,提高了钴物种的分散度,降低了钴的烧结程度,催化剂Co/Ce-SBA-15（Si/Ce=20）具有良好的催化活性,乙醇转化率为96.6%,H₂选择性达到75.5%,反应后积碳率仅为5.6%.     

镁合金铈转化膜的形成及表征

采用X射线光电子能谱（XPS）、原子力显微镜（AFM）、电化学方法等对AZ31镁合金铈转化膜的组成、形貌结构及耐蚀性能进行了表征,并结合成膜动力学研究探讨了膜的形成机制。结果表明,镁合金铈转化膜的主要成分为铈的氧化物/氢氧化物,铈在膜中以三价和四价两种价态存在。膜可以分为两层,内、外层膜由不同的微结构组成,这种微结构的差异使内、外层膜之间结合力较弱,成为限制膜耐蚀性能提高的根本原因之一。成膜过程中,成膜溶液pH值升高,使Ce3＋发生水解反应沉积析出铈的氢氧化物/氧化物。铈转化膜的生长动力学遵循抛物线规律。     

吡啶盐-氯胺前体的合成及在聚氨酯表面固载的抗菌应用

以5,5-二甲基海因为起始原料,经5步反应合成了携有全氟苯基叠氮基团(PFPA)的可固载型吡啶盐-氯胺前体,并在254 nm光照条件下分别将其固载到聚氨酯(PU)膜表面.经稀漂白水处理后,以大肠杆菌(ATCC 25922)和金黄色葡萄球菌(ATCC 25923)为测试菌种,测试了所得膜材料的抗菌活性.结果表明,改性PU膜有良好的抗菌性能,尤其PU表面接枝结构中含较短烷基链的前体时,抗菌活性更优.在制备非溶出型抗菌膜材料的同时也提供了一种惰性材料表面固载氯胺前体的普适方法.     

纳米铈-钨发射材料的结构与热发射性能研究

以纳米Ce—W粉末为原料制备了纳米Ce—W发射材料,利用扫描电镜和原位俄歇电子能谱等现代分析技术研究了材料的形貌、铈的分布和高温扩散、以及材料的表面性能,并采用自行研制的微机控制全自动电子发射测量装置测量了材料热发射性能。研究表明,纳米Ce-W材料晶粒细小,稀土元素铈的分布更弥散均匀,铈向表面扩散的能力增强。高温下材料表层形成了含有超额铈的活性层,纳米Ce-W材料的活性层厚度增大,超额铈的含量增多,Ce／O的活性层更厚,因此热发射性能更优异。     

氯化物熔体中铈离子在铁阴极上的电还原

用循环伏安法、充电曲线和衰减曲线研究了在700～850°CNaCl-KCl-CeCl_3熔体中铈离子在铁电极上的还原过程。Ce(Ⅲ)还原时,首先形成金属间化合物,然后析出纯金属铈。用铁阴极电解制取了含83wt％Ce的Ce-Fe合金,其物相为CeFe_2和Ce。     

非晶/纳米晶Ni-Mo-Ce合金镀层结构及其催化析氢性能

在Ni-Mo合金镀液中添加适量的CeCl3溶液,获得了非晶+纳米晶混合结构的Ni-Mo-Ce合金镀层.用X射线衍射(xRD)和扫描电镜(SEM)测试技术研究镀层结构及其表面形貌.实验结果表明,随着Ce含量的增加,镀层中Mo元素含量有所提高,而Ni元素含量有所降低;镀层的显微硬度先增加后降低,当Ce加入量为2 g·L-1时,显微硬度最高.电解实验表明,Ni-Mo-Ce合金具有比Ni-Mo合金更优异的耐蚀性能和良好的催化析氢性能.     

基于聚氧乙烯-b-聚苯乙烯构筑介孔铈锆固溶体

采用原子转移自由基聚合合成了聚氧乙烯-b-聚苯乙烯(PEO-b-PS)两亲性嵌段共聚物,共聚物的结构通过核磁共振氢谱、凝胶渗透色谱和热失重分析表征;基于所合成嵌段共聚物PEO-b-PS构筑得到介孔铈锆固溶体Ce0. 5Zr0. 5O2。氮气吸脱附测试结果表明,Ce0. 5Zr0. 5O2固溶体孔径可达到10nm,且孔径分布较窄,比表面积在40m2·g-1左右;广角XRD和Raman光谱测试结果表明,所构筑的固溶体材料为均匀的铈锆固溶体。在此我们提出了一种制备具有较大孔径的介孔Ce0. 5Zr0. 5O2固溶体的新方法,通过这一方法可以得到与传统方法制得的铈锆固溶体具有相同晶相结构且孔径可以调控的铈锆固溶体。     

Über die photometrische Bestimmung des Cergehaltes legierter Stähle

After review of literature and experimental work photometry with o-tolidine is preferred as a sensitive, exact and simple procedure to determine < 0.1% cerium in steel. The precipitation with oxalate, thoroughly worked out, is recommended as a simple method to separate cerium from the other elements occurring in steels. With high-alloy steels a double precipitation is necessary. This involves a loss of 4% of cerium which, however, is reproducible and thus can be considered in calibrating. Ce contents from 0.002% to 1,0% can be determined.     

Electrochemical separation of uranium and cerium in molten LiCl–KCl

The electrochemical separation of uranium from cerium in LiCl–KCl eutectic and the electrochemical behavior of Ce(III) were studied. According to the cyclic voltammogram of Ce(III) and the former result of U(III), electrodeposition potential was determined at ?1.65 V (vs Ag/AgCl). The uranium metal was successfully deposited and separated from cerium. The morphology of deposit and cross section of electrode were investigated by SEM, firstly uranium deposit alloys with stainless steel and forms a thin transition layer, and secondly the uranium metal layer grows from the transition layer. The separation factors of uranium/cerium on different recovery ratios were determined through a series of steps. It was found that the content of cerium in the deposit and separation factors declined with increasing the initial concentration of U³⁺ in molten salts; the separation factors remained stable at around 20 in different uranium recovery ratios.     

Two-phase synthesis of colloidal annular-shaped Ce(x)La(1-x)CO3OH nanoarchitectures assembled from small particles and their thermal conversion to derived mixed oxides

Undoped and cerium doped LaCO(3)OH annular-shaped nanoarchitectures with high specific surface area have been fabricated via the thermolysis of Ce(x)La(1-x)(oleate)(3) (x = 0-20 mol %) complexes in a toluene-water system containing tert-butylamine/oleylamine. The products exhibit 400 nm-sized monodisperse annular-shaped nanoarchitectures, which are constituted of 3-5 nm-sized primary particles. A possible mechanism of the reaction of Ce(x)La(1-x)(oleate)(3) and tert-butylamine for the formation of annular-shaped Ce(x)La(1-x)CO(3)OH nanoarchitectures is proposed. The thermal conversion of Ce(x)La(1-x)CO(3)OH to Ce(x)La(1-x)(CO(3))O(2) at 600 °C, to Ce(x)La(1-x)(OH)(3) at 800 °C, final to (Ce(x)La(1-x))(2)O(3-δ) at 900 °C were employed, while the original morphology was essentially unchanged. The dopant concentration was varied from 5 to 20 of cerium ions per LaCO(3)OH nanoparticle. The X-ray diffraction (XRD) results reveal that the cerium dopant could enter easily into the LaCO(3)OH structural lattice, whereas copper could unlikely enter into their lattice because of their large ionic radius difference. The cerium oxidation state was controlled by changing doping concentration. The X-ray photoelectron spectroscopy (XPS) results reveal that only one Ce(3+) oxidation state is in the as-synthesized Ce(x)La(1-x)CO(3)OH samples with cerium concentration ranging from 5 to 20 mol %, whereas both 3+ and 4+ ones coexisted in 20 mol % Ce:LaCO(3)OH structure. Remarkable luminescence emission intensity enhancement of 1.5-9.0 times were observed for Ce(x)La(1-x)CO(3)OH samples with cerium concentration ranging from 5 to 20 mol %, after doping with an undoped LaCO(3)OH.     

Al 6061/SiCp稀土转化膜的组成、结构及性能

铝金属基复合材料以其多方面的优异性能在航空、航天、汽车、电子和光学等工业领域中显示出了十分广泛的应用前景［１ ,２］．某些种类的（如ＳｉＣ颗粒增强）铝金属基复合材料已经开始走向工业规模的应用［３］．然而,在铝金属基复合材料中由于增强体的存在使其内部组织结构极不均匀,在使用环境中极易形成腐蚀微电池而遭受点蚀、剥蚀、磨蚀等等腐蚀形式的破坏［４ ,５］ ．适用于常规铝合金防腐处理方法的阳极氧化法和铬酸盐化学氧化法（Ａｌｏｄｉｎｅ法）存在着下述弊端而不能对铝金属基复合材料起到有效的防腐作用：１）铝金属基复合…     

Preparation and Characterization of the Antibacterial Zn2+ or/and Ce3+ Loaded Montmorillonites

A series of modified montmorillonites including Zn²⁺ loaded montmorillonite (Zn/MMT), Ce³⁺ loaded montmorillonite (Ce/MMT) and Zn²⁺‐Ce³⁺ loaded montmorillonites (Zn‐Ce/MMT) were prepared by an ion‐exchange reaction, and characterized using X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), and scanning electron microscopy (SEM). The specific surface areas, zeta potentials and antibacterial activity of the modified montmorillonites were also investigated. Zinc and cerium were proved to be present as bivalent zinc state and trivalent cerium state in the modified montmorillonites. For the modified montmorillonites, the d₀₀₁ basal spacings increased and the particles were formed of irregular shapes. The antibacterial activity of the modified montmorillonites was enhanced with the increase of specific surface areas and zeta potentials, and Zn²⁺‐Ce³⁺ loaded montmorillonites displayed obvious synergistic antibacterial effect. When Zn/Ce atomic ratio was 1.24, the Zn‐Ce/MMT showed high antibacterial efficiency and broad‐spectrum antibacterial activity, possessing the MIC against Escherichia coli, Staphylococcus aureus, Candida albicans and Mucor of 1500, 1000, 2000 and 3000 mg·L^?1, respectively.     

非晶态Ni-Ce-P合金的共沉积与耐蚀性能

采用恒电位沉积、循环状安等方法研究了在水溶液中电沉积稀土合金的可能性 ,首次在含有CeCl3的弱酸性NaH2 PO2 镀液中获得了不同铈含量的Ni Ce P合金镀层 ,XPS、AES、XRD和SEM等实验技术表征了镀层的组成和结构 ,极化电阻和腐蚀电位的测试数据表明此镀层与Ni P无定形合金相比 ,具有更强的耐腐蚀能力 ,同时 ,讨论了沉积条件与镀层耐蚀性能的关系 ,结论是 :镀层中铈含量越高 ,其耐腐蚀性能越好 ,此外还对Ni Ce P的共沉积机理进行了初步探讨 ,指出在所研究的电沉积条件下 ,Ni Ce P合金共沉积可以用“诱导共沉积理论”合理解释     

Au/Ce1-xZrxO2催化剂的制备、表征及其在CO氧化和水煤气变换反应中的催化性能

采用共沉淀法制备了不同锆铈摩尔比的Ce1-xZrxO2(x=0,0.1,0.3,0.5,0.7,0.9和1.0)氧化物,并以改性的浸渍法制备了金担载量为1%(质量分数)的Au/Ce1-xZrxO2催化剂.考察了催化剂在低温CO氧化和水煤气变换反应中的催化性能.应用氮物理吸附、X射线衍射、透射电镜和H2程序升温还原等技术对氧化物载体及其负载金催化剂进行了表征,并与其催化性能进行了关联.结果表明,与纯CeO2和ZrO2相比,Ce1-xZrxO2的比表面积增大而孔径减小,孔分布更加集中.Zr的加入使表面Ce4 的还原更加困难,使体相Ce4 的还原更加容易.活性组分金的加入有利于铈锆氧化物的还原.ZrO2载体较大的孔径使金在载体表面分散均匀而粒子较小,因此与Au/CeO2和Au/Ce1-xZrxO2相比,Au/ZrO2具有更好的低温CO氧化活性和水煤气变换活性,而Au/CeZrO在高温下的水煤气变换反应中表现出更好的催化性能.     

In situ electro-oxidation and liquid-liquid extraction of cerium(IV) from nitric acid medium using tributyl phosphate and 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate

The process of in situ electro-oxidation of Ce(III) to Ce(IV) followed by its extraction into the organic phase has been investigated for its applicability in the separation of Ce from nitrate medium. Solvent extraction of cerium from nitric acid after its electro-oxidation to fourth valency state was carried out using tributyl phosphate (TBP) and 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate (KSM-17, equivalent to PC-88A). The efficiency of the extractants at different aqueous phase nitric acid concentrations and different electrode potentials were determined. Various reducing agents such as hydroxylamine hydrochloride, sodium nitrite, ferrous sulphate as well as complexing agents like EDTA, oxalic acid etc, were studied as strippants for the back extraction of cerium from the loaded organic phase. The method developed for the extraction of cerium was further extended to the partitioning of cerium from Ce-Am mixture obtained during the KSM-17 based extraction chromatographic elemental fractionation of PUREX High Activity Waste (HAW) solutions. Recovery of Ce obtained in the extraction experiments by batch as well as by continuous flow organic phase was >95% with good radiochemical purity.