矿化剂对黄色颜料Sm_(0.3)Ce_(0.66)Mo_(0.04)O_(1.85+δ)光学性能影响

矿化剂直接影响颜料的合成温度和颜料的呈色性能,本文通过掺杂四种不同矿化剂:Na F、Na Cl、H3BO3和Na2HPO4,改变灼烧温度,制备出黄色颜料Sm0.3Ce0.66Mo0.04O(1.85+δ),用XRD表征其晶体结构,用CIE颜色系统—L*a*b*(1976)色空间体系和紫外可见反射光谱分析其光学性能,结果表明,制备出的黄色颜料均属于立方萤石结构,以H3BO3为矿化剂时,得到鲜艳的黄色颜料,并随灼烧温度升高,反射光谱吸收边发生红移,颜料颜色由淡黄色变为亮黄色。     

MZnPO_4:RE(M=Li,Na,K;RE=Eu~(3+),La~(3+),Ce~(3+))的高温固相合成及其发光性质

采用高温固相反应合成MZn PO4:RE(M=Li,Na,K;RE=Eu3+,La3+,Ce3+),用X射线衍射(XRD)、扫描电镜(SEM)和能谱分析(EDS)等方法对产物进行了表征,并对产物的发光性能进行研究。结果表明:掺杂三价稀土离子Eu3+,La3+,Ce3+没有改变MZn PO4(M=Li,Na,K)的晶体结构和颗粒形貌;在紫外光(260 nm)激发下,Eu3+掺杂的MZn PO4:Eu3+(M=Li,Na,K)改变了MZn PO4(M=Li,Na,K)原有的发光波长,发射橙红色光,主峰位于595 nm附近,为Eu3+的5D0→7F1跃迁发射;La3+,Ce3+掺杂的MZn PO4:RE(M=Li,Na,K,RE=La3+,Ce3+)则发射蓝色光,最高峰对应波长为400~500 nm,没有改变MZn PO4(M=Li,Na,K)的发光波长,但提高了强度,La3+掺杂的强度大于Ce3+掺杂;除了基质本身对发光的贡献外,Ce3+有很弱的5d1→4f1的跃迁发射,而非荧光稀土离子La3+作为添加剂可提高基质材料的荧光性能。     

La、Ce掺杂对水热法合成镍锌铁氧体的影响

采用水热合成法制备镍锌铁氧体粉体,以稀土元素La、Ce进行掺杂,利用SEM和XRD 等手段对样品进行表征.结果表明,La3+、Ce3+掺杂后,La3+、Ce3+离子掺杂进入镍锌铁氧体晶格后,会产生一定的晶格畸变,造成晶粒常数的增大,但对晶体的形貌影响不大.除存在少量大颗粒,立方尖晶石相Ni0.35Zn0.65Fe1.9...     

稀土紫红色陶瓷颜料的制备

采用共沉淀法于低温下合成了含稀土氧化物La2O3,CeO2的紫红色陶瓷颜料，并将合成的颜料应用于陶瓷高温釉料中；此外，通过颜色测定SEM，XRD及能谱分析等手段对颜料的颜色、粒度及结晶构造等进行了表征，并探讨了颜料的呈色机制。结果表明：该颜料在釉料中呈色稳定，可以应用于1320℃的高温，随稀土氧化物含量增加，颜料中析出(La,Ce)(Mn,Fe,Cr)O3晶相，颜料由棕红色转变为紫红色。     

La2O3, Ce2O3掺杂对原位合成Al2O3(p)/TiAl复合材料显微组织与性能的影响

借助XRD, SEM分析及力学性能测试, 分析了La2O3, Ce2O3掺杂对原位合成Al2O3颗粒强化钛铝基复合材料组织与性能的影响, 探讨了稀土氧化物（La2O3, Ce2O3）的细化机制. 研究结果表明： 掺杂稀土氧化物后产物由γ-TiAl/α2-Ti3Al双相、 Al2O3及Al4La或Al4Ce相组成;Al2O3颗粒分布于晶界处, 使基体晶粒得以细化;引入稀土元素后材料的密度明显增强, 氧化铝的团聚现象减弱. 力学性能测试表明, La2O3, Ce2O3的引入, 有效改善了复合材料的力学性能, 尤其是掺杂Ce2O3后, 材料的抗弯强度比未掺杂时提高了160%以上.     

稀土掺杂对LaSrCoO4催化剂性能的影响

采用聚丙烯胺溶胶-凝胶法制备了类钙钛矿La0.7Nd0.3SrCoO4和La0.7Ce0.3SrCoO4复合氧化物催化剂,考察了它们对CO和C3H8的催化氧化活性,并运用XRD,IR,TPR和TPD等手段对催化剂进行了表征.结果表明,稀土掺杂后的LaSrCoO4复合氧化物均为K2NiF4型结构,不同稀土掺杂对LaSrCoO4复合氧化物的CO和C3H8氧化活性的影响不同,Nd掺杂能增加Co3+、化学吸附氧和晶格氧的数量,提高复合氧化物的活性.     

La-Ce共掺杂制备La3+-Ce3+/ZnO及其对亚甲基蓝的光催化降解

采用溶胶凝胶法制备了La-Ce共掺杂的La3+-Ce3+/ZnO光催化剂,同时用同种方法制备了ZnO、La3+/ZnO和Ce3+/ZnO以作对比.通过X射线衍射仪、透射电镜、紫外可见分光光度计,比表面及孔隙度分析仪等对制备的光催化剂进行了表征.以亚甲基蓝为模型污染物对所制备的光催化剂的光催化特性进行了评价.结果表明,所制备的La3+-Ce3+/ZnO光催化剂基本呈长方柱状,尺寸平均为57.3 nm,La-Ce共掺杂提高了ZnO的结晶度,促进了晶粒的长大.根据光催化实验结果,La-Ce共掺杂能够显著提高ZnO的光催化活性.在光催化降解500 mL的10 mg·L-1亚甲基蓝实验中,La3+-Ce3+/ZnO光催化剂对亚甲基蓝的降解率达93.7%,比纯ZnO、La3+-ZnO和Ce3+-ZnO分别提高了21.4%、19.2%和9.3%.      

具有核壳结构的纳米二氧化钛负载银离子掺杂稀土离子抗菌剂的合成、表征及抑菌活性研究

以纳米TiO2粉体和硝酸银及稀土硝酸盐(RE=Ce4+、La3+、Nd3+、Sm3+、Er3+)为原料,采用浸渍法制备了5种具有核壳结构的纳米二氧化钛负载银离子掺杂稀土离子抗菌剂.通过固体紫外-可见光谱、X-射线粉末衍射光谱、X-Ray光电子衍射光谱、透射电镜分析证明掺杂Ce4+的抗菌剂具有核壳结构.采用培养基扩散法、营养肉汤稀释法及贴膜试验对这五种抗菌剂进行了抑菌活性研究,最终证明其具有很好的抑菌性.     

La掺杂对TiO2光催化剂的影响

采用溶胶-凝胶法制备了La掺杂的TiO2.通过X射线衍射分析、扫描电镜、紫外-可见光漫反射测试等手段对TiO2进行了结构和光吸收性能研究.结果表明La3+阻碍了锐钛矿向金红石转变,提高了晶形转变温度,La3+掺杂之后的TiO2粒径变小,La3+掺杂TiO2光吸收与煅烧温度有关.     

Mo—La—Ce稀土钼合金丝材及其制备方法

本发明涉及一种Mo—La—Ce稀土钼合金丝材及其制备方法。其特征在于该钼合金丝材中含有重量百分比为0．4％～1．0％La2O3和CeO2,且La2O3：CeO2的重量比为4：1。制备方法与传统的粉末冶金生产工艺不同,是将二氧化钼、La（NO3）3、Ce（NO3）4溶液进行真空干燥液-固掺杂,而后进行二次还原制取二元稀土掺杂钼粉,再经压制、烧结、压力加工等工序,制备出规格为Ф0．5～0．8mm Mo—La—Ce稀土掺杂钼丝。本发明的原料廉价、易得,所制备的钼丝抗拉强度高、耐磨性能强、工艺简单、不易弯曲脆断、成品率高、一致性好、使用寿命长。     

Study of cerium ion in (Y0.95La0.05)2O3:Ce

(Y0.95La0.05)2O3: Ce3+ nano-powder was synthesized by co-precipitation method and sintered at 800 and 900 oC. All the samples were cubic phase characterized by X-ray diffraction (XRD) analysis. The samples sintered at the lower temperature exhibited luminescence. According to the distinguishable structure of Ce 3d peaks and the shift of O 1s lines in the X-ray photoelectron spectroscopy (XPS), luminescence was further confirmed to originate from Ce3+ ions. Effects of introducing La3+ into Y2O3 were discusse...     

铽在硫氧化镧基质中的光致发光

采用高温固相反应法制备了La2O2S∶Tb3+、La2O2S∶Tb3+,RE3+(RE=Dy,Gd,Ce,Sm)荧光粉样品并进行了相关表征。结果表明,合成样品的晶体结构与La2O2S相同,为六方晶系;荧光粉颗粒的形貌多为长方形片状;发射光谱由494 nm、545 nm、587 nm、622 nm的一系列锐发射峰组成。研究发现Tb3+的掺杂浓度对样品主发射峰545 nm的发光强度影响很大,且在摩尔分数x(Tb3+)=0.02时达到最强。稀土离子Dy3+、Gd3+对La2O2S∶Tb3+荧光粉的发光有明显的敏化作用。     

Influence of Doping Rare Earth on Performance of Lithium Manganese Oxide Spinels as Cathode Materials for Lithium-Ion Batteries

The cathode material plays an important role inthe performance of lithium ion batteries. Commerciallithium cells use lithium cobalt oxide cathodes and thehigh cost of this material has prompted the design andsynthesis of alternate insertion hosts. Among these al ternatives, spinel LiMn2O4 has been found to bepromising in terms of specific energy, non toxicity,and low cost[1~3]. It is thought that lithium man ganese oxides will be used in lithium ion batteries forel…     

Partial Oxidation of Methane to Syngas over Monolithic Ni/γ-Al2O3 Catalyst——Effects of Rare Earths and Other Basic Promoters

Overthe last fewyears ,partial oxidation of meth-ane (POM)tosyngas has attractedincreasing attentioninthe field of catalysis[1 ,2].Compared withtraditionalgranular catalysts , monolithic catalysts are more suit-able for practical application of heterogeneously cata-lyzed gas/liquid reactions ,with many advantages suchas lowpressure drops ,excellent heat and gas conduc-tivity ,and larger external surface areas .The active components in the catalysts of POMmainlyinclude noble metals andtransit…     

Partial Oxidation of Methane to Syngas over Monolithic Ni/γ-Al2O3 Catalyst——Effects of Rare Earths and Other Basic Promoters

A series of monolithic Ni/γ-Al2O3 catalysts with and without basic promoters (Na, Sr, La, Ce) were prepared. Partial oxidation of methane (POM) to syngas was carried out in a continuous-flow, fixed-bed reactor. The influences of reaction conditions, including temperature, CH4/O2 ratio and space velocity, on the performance of the catalyst were investigated. The results show that at a high space velocity of 1×105 h-1, optimal CH4 conversion can be obtained. Effects of promoters such as Na, Sr, Ce, La were also investigated, and the catalyst samples were characterized by means of temperature-programmed reduction and XRD techniques. XRD suggests that the addition of promoters has no influence on the crystal structure of Ni/γ-Al2O3 catalyst. The results show that the addition of a small amount of promoters improves the reducibility and activity of the catalyst. The side reaction CH4 2 O2→CO2 H2O, is fully restrained and 100% H2 selectivity is achieved when Ce and La are used as promoters, respectively.     

Effect of Ln3＋ on Inhibition of Tobacco RuBPcase

Ｉｔｗａｓｐｒｏｖｅｄｂｙｐｒｅｖｉｏｕｓｗｏｒｋｓ[1] ｔｈａｔｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｐｒｏｍｏｔｅｔｈｅｇｒｏｗｔｈａｎｄｄｅ ｖｅｌｏｐｍｅｎｔｏｆｐｌａｎｔｓａｎｄｉｎｃｒｅａｓｅｔｈｅｙｉｅｌｄｏｆｃｒｏｐｓａｔｌｏｗｃｏｎｃｅｎｔｒａｔｉｏｎ ,ｂｕｔｗｈｅｎｔｈｅｃｏｎ ｃｅｎｔｒａｔｉｏｎｉｓｈｉｇｈ ,ｔｈｅｙｗｉｌｌｉｎｈｉｂｉｔｔｈｅｇｒｏｗｔｈｏｆｐｌａｎｔｓ .Ｉｔｗａｓａｌｓｏｐｒｏｖｅｄ[2 ,3] ｔｈａｔｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｅｘｈｉｂｉｔｂｏｔｈｐｏｓ…     

Effects of rare earth addition on microstructure of C–Mn steel

Abstract

The microstructures were observed in C–Mn steel and statistical analysis of the inclusions produced when trace amounts of rare earth were added to the steel. The results show that the content of intragranular acicular ferrite decreased in the order of being treated with La+Ce/La/Ce in C–Mn steel after the treatment of different kinds of rare earths. The optimum mass ratio of La and Ce for La+Ce combined treatment is 3:1.The best incubation time after Le+Ce (3:1) treatment is 5?min. The size of inclusion nuclei favouring intragranular acicular ferrite nucleation concentrates in the range of 1–4?μm. The disregistries between rare earth inclusions and α-Fe are small, which plays an important role in rare earth inclusions inducing intragranular acicular ferrite nucleation.     

Synergetic migration behavior of La and Ce and related microstructure character of Cr-V-RE co-doped WC-Co alloy

The as-sintered sinter skin and the polished section of WC-11Co-0.4Cr 3 C 2-0.3VC-0.2RE(RE=mischmetal with La/Ce ratio of 0.65) alloy were analyzed.It was shown that the microstructures on the skin and in the inner part of the alloy were all characterized with a WC+β+M structure,where β was a cobalt-based binder phase and M represented a RE-containing phase.There existed an inward diffusion of S atoms,which caught and fixed the Ce atoms in the alloy and an outward diffusion of La atoms during the sintering process.Consequently,the M phase was characterized with the decreased La/Ce ratio(0.59) in the inner part and the increased La/Ce ratio(1.01) on the skin.The M phase on the skin was characterized with a γ-Ce 2 S 3 type structure.To suppress the long range migration of rare earth to the skin,S in the sintering atmosphere had to be eliminated.     

Biosorption of La^3＋ and Ce^3＋ by Agrobacterium sp.HN1

The Agrobacterium sp.HN1 was isolated from the soil and used to adsorb rare earth ions La3+ and Ce3+.The results showed that the pretreatments of Agrobacterium sp.HN1 did not enhance the adsorption of La3+ and Ce3+.The pH,temperature,time and bacterial age affected the dynamics of adsorption of La3+ and Ce3+.The optimum adsorption conditions for Agrobacterium sp.HN1 were as follows:15 mg/L La3+ of initial concentration,10 mg/L Ce3+,300 mg/L(dry wt.cell) biomass for sorption,6.8 pH,30 oC temperature,150 r/min rotational speed,2 h adsorption time and 28 h bacterial age.The adsorption kinetics of La3+ and Ce3+ for Agrobacterium sp.HN1 followed the pseudo-second order equation.