纳米Ce/TiO2光催化剂的制备及光催化性能

以TiCl4为原料,Ce(NO3)2·6H2O为掺杂剂,制备了铈掺杂TiO2纳米粒子并进行了X射线衍射表征和气相光催化性能评价。实验结果表明,铈掺杂对样品的光催化活性有影响,随着掺铈量的增加样品的光催化活性提高。掺铈量大于4%以后活性变化不再明显。样品的焙烧温度和时间也对样品的光催化活性有影响。此外,样品的粒径随制备中的pH值降低而减小。     

钙钛矿锰氧化物La_(1.2-x)Tb_xSr_(1.8)Mn_2O_7(x=0,0.05)的磁熵变和电输运性质研究

采用传统固相反应法制备钙钛矿锰氧化物La_(1.2-x)Tb_xSr1.8Mn2O7(x=0,0.05)多晶样品,通过测量样品的磁化强度与温度关系曲线(MT)和磁化强度与外加磁场关系曲线(M-H)对两样品的磁熵变研究发现:在整个温度测量区间内,x=0和x=0.05两样品在高温部分均表现出顺磁性;随着温度的降低,两样品分别在245和225 K处发生了二维短程铁磁有序转变(T_C~(2D));在120和70 K处发生了三维长程铁磁有序转变(T_C~(3D));在低温部分,两样品均表现出团簇自旋玻璃行为。x=0样品在T_C~(3D)附近的磁相变为一级相变,x=0.05样品为二级相变,两样品的磁熵变曲线的对称性良好,且在外场2 T下两样品在T_C~(3D)附近出现的最大磁熵变值分别为:2.17和1.60 J·(kg·K)~(-1),因此两样品有利于应用在埃里克森磁制冷循环中。此外,通过测量零场下电阻率与温度关系曲线(ρ-T)对两样品的电输运性质研究发现:x=0样品和x=0.05样品分别在96和93 K处发生了绝缘-金属转变(T_P),对T_P以上的ρ-T曲线拟合表明,两样品在高温部分均遵循三维变程跳跃的导电方式,Tb3+离子的掺杂没有改变高温区的导电方式。     

纳米Sb2Se3掺杂PZT铁电陶瓷材料的热电性能

采用固相烧结法将Sb2Se3掺杂入PZT铁电陶瓷,以期提升PZT铁电陶瓷的热电性能.对掺杂后的样品材料进行了XRD分析,发现Sb2Se3掺杂融入PZT的效果良好,之后对样品材料的热电性能进行了重点分析.结果表明:随着温度的升高,样品材料的赛贝克系数的绝对值均逐渐增大,且均为负值,掺杂样品的赛贝克系数的绝对值较未掺杂样品...     

镨改性铈锆氧化物固溶体的制备与表征

采用溶胶-凝胶法制备了不同比例的Pr掺杂铈锆氧化物固溶体Ce0.6Zr0.4-xPrxO2-y(x=0.05, 0.10, 0.15).X射线衍射证实形成的固溶体为萤石型立方相结构;BET比表面积分析表明,随着Pr的掺杂量由x=0.05递增到x=0.15,在650℃焙烧的样品其比表面积由66.5m2·g-1增加到79.9m2·g-1,而未掺杂样品Ce0.6Zr0.4O2的比表面积为65.1 m2·g-1;粒度分布及透射电镜分析发现,制备的固溶体在水相中存在着团聚现象.应用在含有Pt, Rh和Pd的三效催化剂的制备.催化活性测试表明,在铈锆氧化物储氧材料中掺杂少量Pr,可降低三效催化剂对CO、C3H6和NO的起燃温度.不论是在富燃区还是在贫燃区,所有掺杂Pr的三效催化剂对各气体的催化转化率均高于未掺杂Pr的三效催化剂.     

V掺杂对La_(0.45)Ca_(0.55)MnO_3电荷有序态及输运性质影响的研究

采用标准固相反应法制备了La0.45Ca0.55Mn1-xVxO3(x=0.00,0.06,0.10,0.12)多晶样品。通过XRD、ρ-T曲线、M-T曲线和ρ-T拟合曲线,研究了Mn位V5+离子掺杂对体系的电荷有序相及输运性质的影响。实验结果表明:随着V5+离子的掺杂量的增加,电荷有序相(CO)逐渐削弱,当x=0.10时,CO相基本融化但还有部分残留,当x=0.12时CO相完全融化;对低掺杂(x=0.00,0.06)样品,表现出复杂磁相:随温度降低,发生顺磁-电荷有序-反铁磁相变,40 K附近,在反铁磁背景下产生再入型自旋玻璃态;随掺杂量增加,体系的电阻率逐渐减小,当掺杂量x≥0.10时,样品发生金属-绝缘体相变,其相变温度随着掺杂量的增加而向高温移动。对于金属型导电机制满足自旋波散射和电-磁子之间的散射,而绝缘体导电机制有两种情况:x≤0.10的样品满足变程跃迁模型ρ=ρ0exp(T0/T)1/4,x=0.12的样品则满足小极化子绝热最近邻跃迁模型ρ=ATexp(Eα/κBT),通过掺杂实现了从变程跃迁到绝热小极化子最近邻跃迁。     

Ca~(2+)掺杂对γ-Ce_2S_3红色色料的结构及性能的影响

以CeO_2为铈源, CaCO_3为离子掺杂源, CS_2为硫源,采用气-固相反应法,在硫化制度900℃硫化150 min时制得Ca~(2+)离子掺杂的γ-Ce_2S_3红色色料。系统研究了不同的Ca, Ce摩尔比(n_(Ca)/n_(Ce)=0～0.5)对γ-Ce_2S_3的物相组成、晶体结构、呈色性能及温度稳定性的影响。研究结果表明:当未掺入Ca~(2+)时,所得样品为纯α相,当n_(Ca)/n_(Ce)=0.1时,为α相与γ相共存;而当n_(Ca)/n_(Ce)=0.2～0.5时,α相已完全转变为γ相,并产生少量的CaS,且随着掺杂量的增大,γ-Ce_2S_3的晶胞参数逐渐减小,产生的CaS含量则略有增加,说明部分Ca~(2+)成功进入晶格并形成固溶体,另有少量Ca~(2+)则与S~(2-)结合形成CaS;随着n_(Ca)/n_(Ce)增加,所合成样品的色调逐渐由暗红色向红色再向橙红色转变,且当n_(Ca)/n_(Ce)=0.4时,样品的红度值a~*达到最高(L~*=31.75,a~*=24.50,b~*=16.01)。将该组分色料在空气气氛中490℃保温10 min后仍以γ相稳定存在,表明通过Ca~(2+)离子的掺杂,填补γ-Ce_2S_3晶格空位并形成固溶体,有利于稳定其晶格,从而使γ-Ce_2S_3的温度稳定性由350℃提升至490℃。     

钇掺杂对Ce0.33Zr0.67O2储氧性能的影响

采用柠檬酸溶胶凝胶法制备了一系列钇掺杂的富锆铈锆复合氧化物Ce0.33YxZr0.67-xO2,并通过XRD,BET,OSC,XPS,in-situ CO-FTIR等测试,系统研究了钇掺杂后铈锆复合氧化物储放氧性能的变化规律及其影响因素。结果表明,钇离子能够进入铈锆晶格形成固溶体,并提高铈锆体系的结构热稳定性。对于新鲜样,钇掺杂可大幅提升Ce0.33Zr0.67O2材料的比表面积,提高单位质量铈锆材料的储氧能力;但老化后,钇掺杂样品的储氧性能随着掺杂量的增加而减小。通过XPS及原位红外吸附性能测试证实,钇在Ce0.33Zr0.67O2材料表面主要取代锆离子,其掺杂会降低样品的表面吸附能力,抑制铈的氧化还原反应,从而导致该体系储氧性能的下降。     

双层钙钛矿锰氧化物Nd_(1.15)Tb_(0.05)Sr_(1.8)Mn_2O_7的磁性和电性研究

采用传统固相反应法制备双层锰氧化物Nd1.15Tb0.05Sr1.8Mn2O7多晶样品,通过测量样品的X射线衍射谱、磁化强度随温度变化曲线(M-T曲线)以及电阻率随温度变化曲线(ρ-T曲线),对其磁性和电输运性质进行了研究。结果表明,样品随温度的升高先后经历了四个磁转变点:奈尔温度点(TN≈50 K)、电荷有序温度点(TCO≈67 K)、居里温度点(TC≈107 K)和类Griffiths温度点(TG≈275 K)。在低温部分样品处于反铁磁-铁磁共存态,表现出了团簇自旋玻璃行为;在TC到TG温度范围内,样品处于铁磁-顺磁共存态,即存在类Griffiths相;在TG温度以上,样品处于纯顺磁态。其电输运性质表明,随温度的升高,样品的磁电阻率降低,没有发生金属-绝缘转变。通过对115 K~300 K温度范围内的ρ-T曲线拟合发现,样品在高温部分基本遵循三维变程跳跃的导电方式。     

CaO掺杂对10NiO-NiFe2O4复合陶瓷致密化及导电性能的影响

研究了CaO的添加量和烧结温度对10NiO-NiFe2O4复合陶瓷的物相组成、致密度和导电性能的影响.结果表明:0%～4% (质量比,下同)CaO含量范围内,烧结样品的XRD图谱仅有NiO和NiFe2O4的衍射峰.CaO掺杂对10NiO-NiFe2O4复合陶瓷具有明显的助烧作用.材料在烧结温度为1 200 ℃,CaO掺杂量为2%时,致密度达到最大为98.75%,比相同温度下未掺杂CaO的样品提高20%左右.CaO掺杂量对1 200℃烧结的10NiO-NiFe2O4复合陶瓷的电导率影响显著.当CaO掺杂量为0%～1%时,材料电导率在500～650℃区间出现1～2个数量级的突降;当CaO质量分数为2%和4%时,材料电导率在30～960℃范围内随着测试温度的升高而增大;其中,添加2?O样品的电导率在960℃下可达到最大为16.29 S/cm.     

(1-x)La0.6Dy0.1Sr0.3MnO3/0.5x(Sb2O3)复合体系的电输运性质及低场磁电阻效应

用固相反应法制备了(1 -x)La0.6Dy0.1Sr0.3MnO3/0.5x( Sb2 O3)系列样品,通过电阻率-温度(ρ-T)曲线以及ρ-T拟合曲线,研究了样品的电输运性质,电输运机制及低场磁电阻效应.结果表明:所有样品在高温区表现为绝缘体导电,在低温区表现为金属导电,产生绝缘体-金属相变;在金属导电区主要是单磁子散射起作用,可以用公式ρ=ρ0+AT拟合;所有样品在整个温区随温度降低MR持续增大,表现出低场磁电阻特征,复合样品的磁电阻(MR)与纯的La0.6Dy0.1Sr0.3 MnO3的MR相比,在低温区减小,在高温区增大,对x=0.15的样品在高温区的MR大幅度提高,当B=0.2 T,T=300 K时,MR达7.79％,比纯La0.6Dy0.1 Sr0.3 MnO3的MR增大2.6倍,有利于MR的实际应用.     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.