Preparation and Long Persistence Red Luminescence of M0.2Ca0.8TiO3∶Pr3+(M=Mg2+,Sr2+,Ba2+,Zn2+)

M0.2Ca0.8TiO3∶Pr3 (M=Mg2 , Sr2 , Ba2 , Zn2 ) long persistence red phosphors were prepared by solid state reaction. The influence of the partially replacing Ca2 in CaTiO3 with Mg2 , Sr2 , Ba2 , Zn2 on the excitation spectra, the emission spectra and the long persistence properties were studied. The results suggest that certain quantity of Mg2 , Sr2 , Ba2 , Zn2 which partially replace Ca2 can enhance the luminescent intensity and prolong the afterglow persistence of the samples. The intensity of Mg0.2Ca0.8TiO3∶Pr3 is above all of the samples. Take Mg0.2Ca0.8TiO3∶Pr3 as the basic sample, the influence of Pr3 concentrations(C(Pr3 )) on the long afterglow properties were also studied. The results suggest that when the C(Pr3 ) is 0.10%(mol fraction) the intensity of the sample is the highest. The excitation spectra of all these samples show broad band spectra ranging from 300～500 nm peaking at about 342 nm. The emission spectra also exhibit a broad band peaking at 613 nm(CaTiO3∶Pr3 is 612 nm). XRD research indicates that the crystalline phases change due to the replacement of divalent metal ions.The research on the thermoluminescence spectra of Mg0.2Ca0.8TiO3∶Pr3 indicates that the peak is at 107.35 ℃ and the depth of the trap energy is about 0.852 eV.     

Enhancement of luminescence and afterglow in Ca0.8Zn0.2TiO3:Pr3+ by Nb5+ substitution for Ti4+

Nb5+ doped Ca0.8Zn0.2TiO3:Pr3+ red long afterglow phosphors were synthesized by solid-state reaction methods. X-ray diffraction, photoluminescence spectroscopy and thermally stimulated spectrometry were used to investigate the effects of Nb5+ content on the crystal characteristics and luminescent properties of Ca0.8Zn0.2Ti1-xNbxO3:Pr3+ phosphors. The results showed that the addition of a small quantity of Nb5+ had negligible effect on the crystal characteristics of Ca0.8Zn0.2Ti1-xNbxO3:Pr3+, but it could change the trapping parameters (the depth of trap, frequency factors and the concentration of trapped charges at t=0) of Ca0.8Zn0.2Ti1-xNbxO3:Pr3+ phosphors, and then led to the enhance-ment of red fluorescence and phosphorescence at 612 nm originating from 1D2→3H4 transition of Pr3+. Both of the red fluorescence intensity and afterglow time reached the largest values in the sample of Ca0.8Zn0.2Ti1-xNbxO3:Pr3+ with x=0.05. The afterglow time of Ca0.8Zn0.2Ti0.95Nb0.05O3:Pr3+ phosphors lasted for over 24 min (≥1 mcd/m2) when the excited source was cut off.     

前驱体法制备Ca0.8Zn0.2TiO3:Pr3+荧光粉及其发光性能

采用前驱体微波加热法、电阻加热法和传统的高温固相法等不同方法制备了Ca0.8Zn0.2TiO3Pr3+荧光粉,以 TG-DSC、XRD、荧光光谱和粒度分析为表征手段,比较了不同方法制备Ca0.8Zn0.2TiO3Pr3+的发光性质.XRD测定结果表明, 前驱体微波加热法和电阻加热法制备的样品可使反应温度低200℃,但材料的晶体化程度不高.TG-DSC的测定结果表明,前驱体在加热达到700℃以上才完全失重.荧光光谱和粒度分析的测定结果表明,与传统的高温固相法制备的荧光粉相比, 前驱体微波加热法和电阻加热法制备的荧光粉具有发光增强和颗粒细小均匀的特点,但微波加热法更为简单.     

Effect of different dopants on the long lasting phosphorescence behavior of CaTiO_3：Pr~（3＋）

In order to improve the luminescence properties of CaTiO3:Pr3+, a series of CaTiO3:Pr3+, such as CaTi0.97Nb0.03O3:Pr3+, Ca0.8Zn0.2TiO3: Pr3+, Ca0.8Zn0.2Ti0.97Nb0.03O3:Pr3+ and B3+-doped Ca0.8Zn0.2Ti0.97Nb0.03O3: Pr3+ were prepared through conventional solid state reaction method. The results of the photoluminescence excitation and emission spectra showed that all the samples emitted red phosphorescence at 612 nm originating from 1D2 to 3H4 emission of Pr3+ under the 337 nm excitation. When examined by the X-ray diffraction (XRD), all the samples presented a predominant phase of CaTiO3 (JCPDS# 42-423) except Zn2+-doped samples which also revealed another phase of Zn2Ti3O8 (JCPDS# 73-579). The results of the afterglow decay curves showed that co-doping Zn2+ ions, Nb5+ ions or adding a small amount of B3+ into Ca0.8Zn0.2Ti0.97Nb0.03O3:Pr3+ were effective in improving the photoluminescence properties of CaTiO3:Pr3+ phosphor. Thermoluminescence results showed that the trap existing in all the samples was the same as in CaTiO3:Pr3+ and doping singly Nb5+ or Zn2+ hardly changed the trap depth but co-doping Nb5+ and Zn2+ could modify the trapping level from 0.63 to 1.26 eV distinctively. In addition, adding a certain amount of B3+ into CTO-PZN could also deepen the trap depth.     

Synthesis of photocatalytic La(1-x)AxTiO3.5-δ(A=Ba,Sr, Ca) nano perovskites and their application for photocatalytic oxidation of congo red dye in aqueous solution

A-site substituted La0.8A0.2TiO3.5–δ(A=Ba, Sr, Ca) nano perovskites were prepared by sol-gel method and characterized using thermogravimetry/differential thermal analysis(TGA/DTA), X-ray diffraction(XRD), ultraviolet-visible(UV-Vis) spectroscopy and transmission electron microscopy(TEM). XRD analysis showed that the La0.8A0.2TiO3.5–δ(A=Ba, Sr, Ca) nano perovskites derived after calcination at 800 oC were in single phase with orthorhombic structure. The particle size of all nano perovskites was found to be ~20 nm. The synthesized nano perovskites were tested for the photocatalytic decomposition of an azo dye, Congo red. The sequential behavior of La0.8A0.2TiO3.5–δ(A=Ba, Sr, Ca) nanoperovskites for photocatalytic decomposition of congo red in aqueous solution by visible light at room temperature was studied at various time intervals and the efficiency of degradation of the nanoperovskites was compared. Among all the A-site substituted La0.8A0.2TiO3.5–δ(A=Ba, Sr, Ca) nano perovskites, Ba substituted compound showed the highest dye degradation.     

Preparation and Characterization of Red Luminescent Ca0.8 Zn0.2 TiO3 ： Pr3 ＋ , Na^＋ Nanophosphor

Nanophosphor with the nominal composition of Ca0.8 Zn0.2 TiO3 ： Pr3 ＋ , Na^＋ （CZTOPN） was synthesized at relatively low temperature by the sol-gel method. Metal ions were dispersed by citric acid in ethylene glycol solvent and then react with Ti（OC4H9）4 to form sol and gel. The decomposition process of the precursor, and crystallization and particle size of CZTOPN were examined by thermal analysis （TG-DSC）, powder X-ray diffraction （XRD）, and scan election microscopy （SEM）. Results of TG-DSC and XRD reveal that the composition of Ca0.8 Zn0.2 TiO3 ： Pr3 ＋ , Na^＋ changes with the sintering temperature. SEM data indicate that the diameter of particles is under 50 nm even if the sintering temperature increases to 1000 ℃. In contrast to a solid state reaction, the excitation spectra of samples synthesized by the sol-gel method shift blue about 10 nm and the emission intensity at 617 nm increases significantly.     

Preparation and Long Persistence Red Luminescence of M0.2Ca0.8TiO3 ： Pr^3＋ （M = Mg^2＋ , Sr^2＋ , Ba^2＋ , Zn^2＋）

M0.2Ca0.8TiO3 : Pr^3 (M = Mg^2 , Sr^2 , Ba^2 , Zn^2 ) long persistence red phosphors were prepared by solid state reaction. The influence of the partially replacing Ca^2 in CaTiO3 with Mg^2 , Sr^2 , Ba^2 , Zn^2 on the excitation spectra, the emission spectra and the long persistence properties were studied. The results suggest that certain quantity of Mg^2 , Sr^2 , Ba^2 , Zn^2 which partially replace Ca^2 can enhance the luminescent intensity and prolong the afterglow persistence of the samples. The intensity of Mg0.2Ca0.8TiO3: Pr^3 is above all of the samples. Take Mg0.2Ca0.8TiO3:Pr^3 as the basic sample, the influence of Pr^3 concentrations (C (Pr^3 )) on the long afterglow properties were also studied.The results suggest that when the C (Pr^3 ) is 0.10% (tool fraction) the intensity of the sample is the highest. The excitation spectra of all these samples show broad band spectra ranging from 300 - 500 nm peaking at about 342 nm. The emission spectra also exhibit a broad band peaking at 613 nm (CaTiO3: Pr^3 is 612 nm). XRD research indicates that the crystalline phases change due to the replacement of divalent metal ions. The research on the thermoluminescence spectra of Mg0.2Ca0.8TiO3:Pr^3 indicates that the peak is at 107.35℃ and the depth of the trap energy is about 0.852 eV.     

一维镨掺杂纳米TiO_2水热合成及光催化性能研究

以钛酸丁酯和硝酸镨为原料,采用水热法制备Pr掺杂的纳米TiO2。通过XRD、SEM以及Raman UVVis DRS等实验方法研究了样品的晶体结构以及光响应性能。结果表明,水热合成条件对镨掺杂纳米TiO2的形貌及光催化性能有显著的影响。其中在5 mol/L的NaOH碱液环境下,控制水热处理温度为150℃,水热时间为12 h,掺镨量为0.5%(质量分数),热处理温度为500℃,所合成的一维镨掺杂纳米TiO2光催化效果最优。另Pr3+掺杂使纳米TiO2提高了对可见光的吸收能力,并使其吸光域红移约50 nm。     

纳米晶WC-10Co复合粉末的烧结致密化行为

研究了机械合金化纳米晶WC-10Co复合粉末的真空烧结致密化行为和一般规律。结果表明:提高烧结温度和延长烧结时间有利于样品的烧结致密化过程,在1275-1300℃时致密化速度较快,在1300℃烧结15min后致密化过程基本完成;VC和Cr3C2复合晶粒长大抑制剂含量的增加不利于致密化过程;新型晶粒长大抑制剂A可以更有效地抑制晶粒长大;纳米晶WC-10Co-0.8VC／Cr3C2-0.2A复合粉末压坯在1375℃烧结30min后,所得的烧结密度为14.48g／cm3,晶粒尺寸约为180nm。     

La0.8Ca0.2CrO3体系复合氧化物的甘氨酸-硝酸盐法合成与导电性能

采用甘氨酸-硝酸盐法合成La0.8Ca0.2CrO3复合氧化物粉料,对合成产物的晶体结构和显微形貌进行表征,研究烧成温度对La0.8Ca0.2CrO3相对密度和电导率的影响.实验结果表明,烧成温度为1400℃时样品即达较高的相对密度(92.6%),测试温度为800℃时样品的电导率为31.1 S·cm-1.与常规固相法相比,GNP法合成产物的纯度高、颗粒细(100nm～200nm),有良好的烧结活性,能够有效地降低材料的烧成温度和提高材料的电性能.     

熔炼次数对M17返回料合金成分、组织和性能的影响

实验结果表明,M17铸造高温合金(%:0.16C、8.79Cr、5.79A1、4.93Ti、3.29Mo、15.20Co、0.78V、0.015B、0.073Zr、0.002S、0.001P、0.001 1O、0.001 0N)经25 kg真空感应炉返回重熔后,Si含量随重熔次数的增加而略有增加,合金中主要元素和其它杂质元素S、P、H的含量变化不大,而氧、氮略有增加;合金中初生碳化物由新合金中的草书体逐渐向返回合金块状转变,初生碳化物的遗传性堵塞合金凝固时的补缩通道,使返回料合金的疏松倾向增大,高温塑性下降较大。     

Shijiazhuang will Build the World's Biggest Replacingcopper-with-aluminum Cable Production Base

正Shijiazhuang City will build the world’s biggest replacing-copper-with-aluminum cable production base,the annual output value can reach 100 billion yuan,in the future it will develop replacing-copper-with-aluminum highend industry cluster.This piece of news was learned by the reporter at the Rare Earth highiron Aluminum Alloy[Nonferrous Business Opportunity:Aluminum alloy door]Cable Conductor New Technology Application Seminar held at the provincial capital.     

Chongqing is Preparing to Set Up Nonferrous Metal Exchange,in a Bid to Become the Transit Place of Kazakhstan Copper

正Since the beginning of Chongqing’s upgrading to a municipality directly under the Central Government,Chongqing City has established direct friendly relationship with Almaty,Kazakhstan,and carried out a series of cooperation in commerce and trade,and culture     

Guangxi Baise Extends Industrial Chain to Combat Loss in Aluminum Business

正"For each tonne of aluminum being produced,the upstream enterprise on the aluminum industrial chain will suffer loss about 2000yuan."Said Liang Xiao,Deputy Director of Pingguo Industrial Park Management Committee under the Guangxi Baise City,one of the four major aluminum industry bases in China,on August 11.Extending aluminum     

JOURNAL OF IRON AND STEEL RESEARCH INTERNATIONAL ANNUAL CONTENTS Volume 21(2014)

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Chinalco Straightened Out Copper Assets,and Delegated Stock Equity of Yunnan Copper

正Immediately after the news that Chinalco transferred 58%stock equity of Yunnan Copper Group to its wholly-owned subsidiary China Copper Corporation Limited free of charge was disclosed on July 9,many individual investors couldn’t help but to think:Does it mean China Copper Corporation Limited will assemble assets for overall listing?At present,among main copper business companies under China Copper Corporation     

The Development and Reform Commission Encourages Private Capital to Enter Geological Prospecting Field

正At the press conference recently held by the National Development and Reform Commission under the theme"Deepen Reform in Investment AuditApproval System",when answering questions from reporters,Huang Min,Director of the Department of Fixed Assets Investment of the National Development and Reform Commission,said that in the future it would continue to intensify efforts in geological prospecting,and actively guide social capital to enter this field.     

Guangxi's first Nickel Industry Development Research Report Was Released

正Recently,Guangxi Metallurgical Research Institute,a subsidiary of Guangxi Nonferrous Metals Group,completed survey on laterite and related manufacturers in the region,by combining the current development status of laterite both at home and abroad,it compiled Guangxi’s first"Research Report on the Development of Guangxi Nickel Industrial Chain"which adopted laterite as the study subject.This report expounded on the current     

China’s Major Non-ferrous Metals Imports & Exports(End of September. 2014)

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China's Major Non-ferrous Metals Imports & Exports

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