Hydrophilic and photocatalytic performances of lanthanum doped titanium dioxide thin films

Pure and La-doped TiO2 thin films were prepared on glass by sol-gel method using tetrabutyl titanate as Ti precursors. Their chemical composition, structure and properties were characterized by X-ray d...     

Synthesis and antitumor activities of rare earth substituted phosphotungstates containing 5-fluorouracil

Two novel rare earth substituted phosphotungstates containing 5-fluorouracil,K 9(C 4 H 4 FN 2 O 2) 2 Nd(PW 11 O 39) 2 ·25H 2 O(FNdPW) and K 9(C 4 H 4 FN 2 O 2) 2 Ce(PW 11 O 39) 2 ·23H 2 O(FCePW),were synthesized and characterized by elementary analysis,FT-IR spectra,X-ray powder diffraction and 1 H NMR.The thermal analysis showed that FNdPW decomposed at 210 and 493 oC,and FCePW decomposed at 223 and 471 oC,both of which had good thermal stabilities.MTT tests were performed to study the antitumor activities against HeLa cells and HepG-2 cells of FNdPW,FCePW,5-fluorouracil,C 4 H 4 FN 2 O 2 H 2 PW 12 O 40 ·8H 2 O and K 11 Ln(PW 11 O 39) 2 ·xH 2 O(Ln=Nd,Ce),and their cytotoxicities against HEK 293 cells.The results showed that FNdPW and FCePW possessed higher antitumor activities and lower cytotoxicities than those of 5-fluorouracil and C 4 H 4 FN 2 O 2 H 2 PW 12 O 40 ·8H 2 O,of which FNdPW exhibited the highest antitumor activates against HeLa cells(EC 50 =3.41×10-6 mol/L) and HepG-2 cells(EC 50 =6.24×10-6 mol/L).Thus the introduction of rare earth elements and 5-fluorouracil could significantly enhance antitumor effect of polyoxometalates.     

Global rare earth resources and scenarios of future rare earth industry

It is known to all that China is abundant in rare earth resources.But rare earth deposits are really not that rare in the earth crust.In the five continents,i.e.Asia,Europe,Australia,North and South America,and Africa,there are about thirty four countries found to have rare earth deposits;Brazil might surpass China and rank the first in rare earth deposits.At present,investment in rare earth production was surged,there have been about 200 projects,and the total production for 25 of them would be more than 170 thousand tons after 2015,a multi-supply system on rare earths is being established worldwide.Cautions on the investment of rare earth production are involved.     

Dual-functionalization based on combination of quercetin compound and rare earth nanoparticle

While the nanoparticles like La2O3 and other rare earth oxides were believed to be able to provide effective scavenging hydroxyl radical.Quercetin,a hydrophobic agent,showed some potential antibacterial activity.The present work successfully performed the surface modification of rare earth nanoparticle using facile and general strategy.In specific,the hydrophobic quercetin was grafted on the rare earth nanoparticle through the coupling with silane.The surface modified nanoparticle was characterized by Fourier-transform infrared(FTIR),thermogravimetric analysis(TGA),and scanning electron microscopy(SEM).The surface modification helped to retain both the scavenging hydroxyl radical property of rare earth nanoparticle and the antibacterial activity of quercetin.This dual-function properties showed potential for application in the development of biomedicine such as antioxidant,anti-inflammatory,antibacterial and anticancer.     

碱熔预处理对废旧稀土荧光粉中稀土提取的影响

针对废旧稀土荧光粉特性,采用高温碱熔与酸浸相结合的方法处理废旧稀土荧光粉,考察碱熔温度、氢氧化钠用量、碱熔时间对稀土浸出率和铝回收率的影响,并对碱熔过程中的物相及形貌变化进行分析.结果表明,在碱熔温度为1050℃、氢氧化钠与废粉质量比为2.5∶1、碱熔时间为2 h 条件下,其稀土浸出率可达98%以上,铝回收率可达98%.通过对碱熔产物物相和形貌分析表明,废粉晶体结构被有效破坏,其中稀土以稀土氧化物形式存在,碱熔产物变成无定型云絮状.     

稀土分析检测方法标准述评

从稀土矿、稀土精矿、稀土金属及其氧化物、稀土深加工产品等方面概述我国稀土分析国家标准体系.其中稀土配分、三氧化二铝、稀土总量、水分、灼减量等参数的检测,是稀土交易和萃取分离工艺过程中重要的技术指标;而钕铁硼、灯用稀土三基色荧光粉、稀土硅铁合金等分析标准,对于稀土磁性材料、稀土发光材料、稀土合金等稀土深加工产品的生产都有重要的指导意义;稀土产品及分析方法的建立,完善了稀土国家标准体系,满足了稀土生产和贸易的需要,促进了稀土行业持续健康发展.      

稀土元素对耐候钢元素偏析的影响

应用金属原位统计分布分析技术(OPA)研究了耐候钢铸锭中C、P、S、Cu、Si和Mn的宏观偏析规律,并分析了稀土元素对耐候钢中元素偏析的影响.结果表明,在30%～40%等轴晶率,20℃过热度下,元素C、S、P和Cu能产生严重的宏观偏析,C、S呈中心正偏析,P、Cu呈中心负偏析并伴随有反偏析,而Si和Mn的分布较为均匀.各个元素中心偏析位置完全相同.稀土元素在钢中的固溶度为10-5～10-4,固溶稀土元素可以细化枝晶,提高等轴晶率.钢中加入质量分数0.38%～0.55%的稀土元素可以有效改善C、S、P和Cu的宏观偏析.     

硅钼蓝分光光度法测定氟化稀土中二氧化硅

氟化稀土是一种用途广泛的材料,其中二氧化硅的含量是衡量产品品质的一个关键指标,直接影响生产合金的工艺和产品的质量。实验采用碳酸钠-硼酸混合熔剂(m_碳酸钠:m_硼酸=4:1)熔融试样,经盐酸酸化,加入0.4 mL硫酸(1+5)控制显色体系的pH≈1,正硅酸与钼酸铵沸水浴保温时间为3～5 s时形成硅钼杂多酸,用草酸-硫酸混合酸破坏磷、砷等干扰元素,抗坏血酸还原硅钼杂多酸为硅钼蓝,建立了光度法测定氟化稀土中二氧化硅含量的方法。试验表明,显色液中二氧化硅质量浓度在0.04～2.0 μg/mL范围内符合比尔定律,方法中二氧化硅的检出限和测定下限分别为0.002 8%和0.010%(质量分数)。方法用于3个氟化稀土实际样品中二氧化硅量的测定,结果的相对标准偏差(RSD,n=10)为2.3%～5.2%;测定值与电感耦合等离子体原子发射光谱法(ICP-AES)的测定结果一致。     

稀土铈对钛微合金钢中TiC和Ti（C，N）析出的影响

摘要：采用扫描电镜对不同稀土含量钢中的稀土碳化物复合相进行观察,随着稀土含量的增加,在晶界析出的稀土夹杂物数量不断增加,抑制了在晶界连续析出的TiC,降低了大尺寸TiC,Ti(C,N)的数量。稀土与碳化物主要复合相变化顺序为CeAlO3-TiC→Ce2O2S-TiC/CeS-TiC→CeP-TiC;其中CeAlO3、Ce2O2S和CeS复合相主要为5μm以下的球形、近球形;CeP复合相主要为大于5μm的条状。采用OTS夹杂物统计软件对不同稀土含量的实验钢进行统计,随着稀土含量的上升,2μm以下的TiC、Ti(C,N)数量先上升后下降,在稀土质量分数为130×10-6时达到最佳;10μm以上的大尺寸TiC、Ti(C,N)呈下降趋势。TiC、Ti(C,N)颗粒的平均尺寸在降低。但是当稀土质量分数达到190×10-6时,小尺寸TiC、Ti(C,N)的数量下降;颗粒平均尺寸上升。     

世界稀土资源供需现状与中国产业政策研究

稀土资源已经成为世界现代工业化建设中不可或缺的因素,有着重要的战略价值.根据世界稀土资源的分布现状及世界稀土资源的供求状况,并结合我国稀土资源开采利用中存在的盲目滥采、落后开采、生态环境破坏严重、稀土产品深加工和后处理工艺技术水平低等问题,分析了我国进行稀土资源调控的政策方向,即建立稀土资源国家战略储备机制、建立并健全稀土期货交易市场、加强稀土产业政策的执行力度、谨慎制订稀土出口配额以及对稀土勘探、开采、分离、冶炼、深加工以及出口等设立专题分别进行重点研究与攻关,对我国未来稀土产业健康发展具有重要意义.      

Local concentration of middle and heavy rare earth elements in the col on the weathered crust elution-deposited rare earth ores

This present study focused on investigating the content and relative enrichment multiple of rare earth elements(REEs) in different terrain of weathered ore body, and the value of light rare earth elements/middle and heavy rare earth elements(LREEs/HREEs), in order to understand the mobilization and redistribution of HREEs, Furthermore, the abrasion pH was investigated as well, The results show that the average contents of HREEs in the knap, ridge and col are 37.26, 61.71, and 271.3 μg/g, respectively. The value of LREEs/HREEs is decreased from 16.78 to 7.914 between knap and col and the relative enrichment multiple of HREEs is as follows: C_(Col-HREEs) C_(Ridge-HREEs) 0. It is indicated the HREEs is concentrated in the col and the enrichment degree of HREEs is stronger than the ridge and the knap. Rare earth elements fractionation is exhibited in the different terrain of weathered ore body. Based on this study, the finding that HREEs concentrate in the lower terrain of weathered crust elution-deposited rare earth ores, such as in the col, would become a marker or indicator to search for middle and heavy rare earth enriched zone.     

Preparation of Y-H3PW12O40/TiO2 and La-H3PW12O40/TiO2 by hydrothermal method and its photocatalytic activity for dinitrotoluene decomposition

A series of mesoporous materials （H3PW12O40/TiO2, Y-H3PW12O40/TiO2 and La-H3PW12O40/TiO2） were prepared by a modified sol-gel-hydrothermal route, which realized the load and modification of H3PW12O40 at the same time. The prepared samples were characterized by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FT-IR）, nitrogen adsorption-desorption analysis, ultraviolet-visible absorption spectrum （UV-Vis） and scanning electron microscopy （SEM）. The XRD and FT-IR results displayed that the catalysts had uniform anatase phase and the primary Keggin structure of H3PW12O40 remain intact. Nitrogen ad-sorption-desorption analysis suggested that suitable doping of rare earth elements could increase the specific surface area from 177.9 m2/g （H3PW12O40/TiO2） to 229.5 （1 wt.%Y-H3PW12O40/TiO2） or 236.1 m2/g （1 wt.%La-H3PW12O40/TiO2）. Results of UV-Vis spectra showed that the band of the 1 wt.%Y-H3PW12O40/TiO2 and 1 wt.%La-H3PW12O40/TiO2 have an obvious redshift compared with the H3PW12O40/TiO2. Additionally, the composites were used as heterogeneous photocatalysts to the degradation of dinitrotoluene （DNT）. It is the first time that polyoxometalate （POM） is applied in the degradation of explosive wastewater.     

Synthesis and thermoluminescence properties of rare earth oxides （Y, Ce-Lu） doped lithium triborate

Lithium triborate (LiB3O5) was synthesized by high temperature solid-state reaction method, and then rare earth oxides were doped into LiB3O5 to enhance its thermoluminescent (TL) properties. The identification and characteristics of the obtained compounds were determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) analyses, differential thermal analyses (DTA) and scanning electron microscopy (SEM). The glow curves were obtained using a thermoluminescent (TL) reader. The results revealed that all the rare earth oxides were not good activators for lithium triborate and the obtained compounds could not be used for dosimetric applications.     

电感耦合等离子体质谱法测定离子型稀土矿中离子相稀土总量及分量

采用硫酸铵溶液提取离子型稀土原矿试样中离子相稀土,以硫酸铵溶液为基体配制校准系列溶液,建立了电感耦合等离子体质谱法(ICP-MS)测定样品溶液中离子相稀土总量及分量的方法。实验表明:对于10.00 g离子型稀土矿试样,加入100 mL 50 g/L硫酸铵溶液振荡15 min后放置30 min可有效提取出离子相稀土;采用5.0 g/L硫酸铵溶液进行校准系列溶液的基体匹配,选择¹⁰³Rh-¹⁸⁵Re双内标可有效校正硫酸铵的基体效应及仪器信号的漂移影响;选择合适的同位素消除了可能存在的质谱干扰。在最佳条件下进行测定,15个稀土元素的校准曲线在10.0~100.0 μg/L范围内线性相关系数均大于0.999 91,方法检出限在0.10~0.66 μg/g之间。方法应用于不同离子型稀土矿区中离子相稀土总量及分量的测定,结果与电感耦合等离子体原子发射光谱法(ICP-AES)一致,相对标准偏差(RSD,n=11)在1.0%~5.2%之间,回收率在98%~104%之间。     

Development of novel rare earth doped fluoride and oxide scintillators for two-dimensional imaging

Two topics were focused.The first one was about the gamma-ray scintillator,Pr3+:Lu3Al5O12(LuAG) .The second one was about neutron scintillator,Ce3+:6LiCaAlF6 and Eu2+:6LiCaAlF6(6LiCAF) .Those scintillators have been developed very recently for modern imaging appli-cations in the medical and homeland security fields.In both cases,the rare earth ions are playing the crucial role as emission centers.Pr3+ in LuAG provided fast 5d→4f transition providing noticeably shorter decay time than that of Ce3+.Among several candidate hosts,LuAG showed the best performance.Bulk crystal growth,basic scintillation properties,two-dimensional gamma-ray imaging and positron emission mammography(PEM) application were demonstrated.Due to the international situation,the homeland security was compromized by illicit traffic of explosives,drugs,nuclear materials,etc.and the ways to its improvement became an important R&D topic.For this purpose the Ce and Eu doped LiCAF ap-peared competitive candidates.Especially,when substitution of 3He neutron detectors was considered,the discrimination ability of gamma-ray from alpha-ray was important.Bulk crystal growth,basic scintillation properties and two-dimensional neutron imaging were demonstrated.     

稀土元素的添加对原位生成的Ti-TiC-TiB复合材料抗磨损性能的影响

采用Ti 6Al 4V 5B4C和Ti 6Al 4V 5B4C 1Nd 两种成分的原始粉末, 反应热压后原位生成了Ti TiC TiB复合材料。经过X射线检测, 证明了试验中原位生成反应5Ti+B4C 4TiB+TiC的进行。采用摩擦磨损试验机检测了两种材料的抗磨损性能。通过扫描电子显微镜和电子探针分析了材料的磨损表面。结果表明, 添加稀土元素能提高材料的硬度, 韧性和抗磨损性能。     

Effect of titanium dioxide and gadolinium dopants on photocatalytic behavior for acriflavine dye

Herein,we report the experimental methodology to optimize the operational parameters of the photocatalytic degradation of acriflavine dye using TiO₂ and Gd³⁺ as dopant.A series of Gd³⁺ doped TiO₂ nanoparticles were synthesized via hydrothermal route and characterized using various techniques like FT-IR,UV,XRD,FESEM and EDS.It is observed that synthesized particles are in the range of 25-30 nm with spherical shape in nature.TiO₂ has rutile ph...     

赣州稀土产业发展简论

通过对赣州稀土产业现状、赣州稀土产业发展优势与存在问题的分析,提出赣州要利用丰富的离子型稀土资源,打造稀土优势产业的建议,建议的主要内容有：优化资源配置,促进精深加工;引进战略投资,延伸产业链条;加快平台建设,健全服务体系;推进资本运作,提高产业发展动力;加大技术创新,促进产业技术进步;完善配套产业,拓宽产业发展空间;建立稀土储备体系,应对价格波动.     

稀土在非TiO2光催化剂的改性研究

近年来,运用稀土改性非TiO2光催化剂取得了显著成果。重点归纳、总结和分析了通过稀土离子单掺或共掺、稀土氧化物复合、上转换光催化与稀土固熔体等手段改性锌基、铋基光催化剂。简单介绍了稀土在钨基等其他基质的应用及新型稀土化合物光催化剂的构筑。发现稀土改性可以影响非TiO2光催化剂的晶格结构能带能、拓宽光谱响应范围和提高量子效率,是提高其光催化活性的有效途径。还对稀土在未来光催化的应用做了分析。     

Band gap calculation and photo catalytic activity of rare earths doped rutile TiO2

The density of states (DOS) of 17 kinds of rare earths (RE) doped futile TiO2 was by using fast-principles density functional the-ory (DFF) calculation. The band gap widths of RE doped rutile TiO2 were important factors for altering their absorbing wavelengths. The results show that RE ions could obviously reduce the band gap widths and form of energy of rutile TiO2 except Lu, Y, Yb and Sc, and the order of absorbing wavelengths of RE doped rutile TiO2 were the same as that of the results of calculation. The ratio of RE dopant was an-other important factor for the photo catalytic activity of RE doped rutile TiO2, and there was an optimal ratio of dopant. There was a constant for predigesting the calculation difficulty, respectively, which were 0.5mol.% and 100 mol-1 under supposition. The band gap widths of RE doped rutile TiO2 by DFT calculation were much larger than that by experiment. Finally, by transferring the calculation values to experiment values, it could be found and predicted that RE enlarged obviously the absorbing wavelengh of futile TiO2. In addition, the degree of RE ions edging out the Ti atom using the parameters of RE elements was computed.