微乳液法制备（Y,Gd）2O3：Eu^3＋纳米粒子及光谱特性

采用反相微乳液法制备(Y,Gd)2O3:Eu3 纳米粉体.通过XRD、TG/DSC、SEM、TEM、PL等手段分别对样品的晶化过程、晶粒尺寸、粉体形貌以及发光性能进行分析.结果表明:晶粒尺寸随着晶化温度提高而增加,样品在800℃晶化完全.当乳液浓度为0.37 mol/L时所得粉体颗粒呈近似球形,一次粒径尺寸约20 am.样品在612nm监控光下得到的激发光谱是宽带谱,对应着Eu3 -O2-的电荷迁移带跃迁.发射光谱的特征峰位于612nm处,是由于Eu3 离子的5D0-7F2跃迁造成的.当Eu的原子分数大于10%时发生浓度猝火,导致特征峰强度降低.     

（Y，Gd）2O3：Eu^3＋纳米粒子制备及光谱特性

用湿化学共沉淀法制备了(Y,Gd)2O3:Eu3 纳米粒子.用XRD,TEM,SEM及差示/热重分析(DSC/TG)手段对粉体进行了表征.用荧光光度计分析了样品的激发光谱和发射光谱.结果表明:在煅烧温度为800℃保温2 h时,合成出近似球形、粒径均匀且分散性好的(Y,Gd)2O3:Eu3 纳米粒子,一次颗粒尺寸约为20 nm.样品在波长为612.0 nm监控光下激发,出现235和250 nm两个激发峰,分别为(Y,Gd)2O3基质吸收和Eu3 迁移态(CTS)吸收造成的.两个波长激发下的发射光谱峰强度前者高于后者.当掺杂Eu3 的摩尔浓度为3%时,发射光谱对应5D0→7F2能级跃迁的相对峰强度最大,当Eu3 掺杂的摩尔浓度为7%时,相对峰强度反而降低,这是由于Eu3 的浓度猝灭造成的.     

PREPARATION AND CHAIACTERISTICS OF (Y,Gd)2O3:Eu3+ NANOPARTICLES

用湿化学共沉淀法制备了(Y, Gd)2O3:Eu3+纳米粒子. 用XRD, TEM, SEM及差示/热重分析 (DSC/TG)手段对粉体进行了表征. 用荧光光度计分析了样品的激发光谱和发射光谱. 结果表明： 在煅烧温度为800 ℃保温2 h时, 合成出近似球形、粒径均匀且分散性好的(Y, Gd)2O3:Eu3+纳米粒 子, 一次颗粒尺寸约为20 nm. 样品在波长为612.0 nm监控光下激发, 出现235和250 nm两个激发 峰, 分别为(Y, Gd)2O3基质吸收和Eu3+迁移态(CTS)吸收造成的. 两个波长激发下的发射光谱峰强 度前者高于后者. 当掺杂Eu3的摩尔浓度为3%时, 发射光谱对应5D07F2 能级跃迁的相对峰强度 最大, 当Eu3+掺杂的摩尔浓度为7%时, 相对峰强度反而降低, 这是由于Eu3+的浓度猝灭造成的.     

Y2-x-yGdxEuyO3纳米材料制备过程中的固溶行为及其发光性能

用柠檬酸螯合法制备Y2-x-yGdxEuyO3纳米粉体(x+y≤2),通过FTIR,XRD和SEM分析了制备过程中的物相变化以及pH值对粉体形貌的影响.测试了Y2-x-yGdxEuyO3晶格常数和晶胞体积,分析了Gd与Eu在Y2O3中的同溶行为及其发光性能.结果表明:在pH<3的体系中制备Y2-x-yGdxEuyO3粉体较为适合,经900℃煅烧2 h可完全合成出立方相的Y2-x-yGdxEuyO3;在pH=l时,加入少量乙二醇(5%,体积分数)时得到粉体形貌最佳,粒径约90 nm,近球形.样品的发光性能和Y,Gd的配比以及Eu的含量有关,当化学配比为Y0.2Gd1.65Eu0.15O3时样品发光强度最高,y值超过0.15会发生浓度猝灭,导致发光强度降低.     

Y_2O_3:Eu,Tb纳米荧光粉的制备与发光性能

以氧化钇、氧化铕、氧化铽、硝酸、柠檬酸等为原料,采用溶胶凝胶法制备Y_2O_3:Eu,Tb荧光粉体。通过X射线衍射分析(XRD)研究前驱体煅烧产物随温度变化的过程,用透射电镜(TEM)观察粉体的显微形貌,使用荧光光谱仪分析样品的激发和发射光谱。结果表明,1100℃煅烧3h可以得到结晶良好的纳米粉体,颗粒呈不规则形状,粒径分布在30~100nm之间。Y_(2(1-x))O_3:Tb_(2x)的粉体具有良好的发光性能,最佳掺杂浓度为1.0mol%。Y1.98-2xO_3:Eu0.02,Tb_(2x)粉体的发光同时表现出Eu~(3+)和Tb~(3+)的发光特征,两种离子之间存在能量传递,当Tb~(3+)离子用量大于1.0mol%时,出现浓度猝灭。     

凝胶-燃烧法合成(Y,Gd)Al3(BO3)4:Tb3+荧光材料的结构及其发光性能

采用凝胶-燃烧法合成掺Tb3+和Gd3+的四硼酸铝钇(Y,Gd)Al3(BO3)4:Tb3+荧光粉.分别采用X射线衍射仪(XRD)、扫描电镜(SEM)、发光光谱等测试手段分析不同温度下煅烧所得粉体的物相、形貌与发光性质.XRD和SEM结果表明:(Y,Gd)Al3(BO3)4:Tb3+的最低合成温度为1000 ℃,在该反应过程中,首先形成中间相Al4B2O9、YBO3和Y3Al5O12,而最终形成单相的(Y,Gd)Al3(BO3)4:Tb3+.随煅烧温度的升高,样品结晶程度越来越好,并且颗粒尺寸随温度的升高而增大,在1100 ℃时合成的晶粒尺寸比较均匀,平均粒径在1 μm左右.发光光谱的测试结果表明:在229 nm激发下,(Y,Gd)Al3(BO3)4: Tb3+荧光粉最强发射峰位于542 nm处,属于Tb3+的5D4→7F5的跃迁.在该体系中存在Gd3+→Tb3+的能量传递,使得该荧光粉的发光强度随着Gd3+掺杂浓度的增加而增大.     

Eu~(3+)掺杂RE_2Sn_2O_7(RE=La,Gd,Y)纳米荧光材料的水热合成与发光性能

采用水热法合成Eu3+掺杂的RE2Sn2O7(RE=La,Gd,Y)系列样品,并采用XRD、SEM、FT-IR和荧光光谱对合成产物的晶体结构、颗粒尺寸、形貌和光学性能进行研究。结果表明:水热合成产物为单一相烧绿石结构的RE2Sn2O7:Eu3+(RE=La,Gd,Y),产物具有由一次纳米颗粒团聚而成的不规则球状形貌。激发光谱和发射光谱测试结果表明:Eu3+掺杂RE2Sn2O7(RE=La,Gd,Y)样品可以被紫外光有效地激发,发射出Eu3+离子特征的橙红色光。与其他样品相比,Gd2Sn2O7:Eu3+样品具有最强的橙红色发光,并对其原因进行了分析。     

超声喷雾共沉淀法制备纳米铕掺杂钇铝石榴石荧光粉

以NH4HCO3与NH3·H2O的混合溶液为沉淀剂,用超声喷雾共沉淀法获得Eu:YAG粉末先驱体,经一定温度煅烧后得到纳米铕掺杂钇铝石榴石(Eu:YAG)荧光粉。用荧光光谱仪、X射线衍射仪、扫描电子显微镜对粉体的结构、物相组成、颗粒形貌进行了研究。详细地研究了不同铕掺杂浓度粉体的发射光谱和激发光谱特性。结果表明:采用超声喷雾技术能获得大小为50～70nm、颗粒度均匀的Eu:YAG纳米颗粒,与溶胶-凝胶等方法制备的颗粒大小与均匀性相比,显示出一定的优势。同时研究还表明,烧结温度对Eu:YAG荧光粉的析晶有重要影响,随着烧结温度的升高,衍射峰逐渐变窄,衍射强度增大,有利于促进YAG相的生成。因此利用超声喷雾共沉淀法制备红色Eu:YAG荧光粉体是一种有效的途径。     

Y2-x-yGdxEuyO3纳米材料制备过程中的固溶行为及其发光性能术

用柠檬酸螯合法制备Y2-x-yGdxEuyO3纳米粉体（x＋y≤2）,通过FTIR,XRD和SEM分析了制备过程中的物相变化以及pH值对粉体形貌的影响．测试了Y2-x-yGdxEuyO3晶格常数和晶胞体积,分析了Gd与Eu在Y2O3中的固溶行为及其发光性能．结果表明：在pH〈3的体系中制备Y2-x-yGdxEuyO3粉体较为适合,经900℃煅烧2h可完全合成出立方相的Y2-x-yGdxEuyO3;在pH=1时,加入少量乙二醇（5％,体积分数）时得到粉体形貌最佳,粒径约90nm,近球形．样品的发光性能和Y,Gd的配比以及Eu的含量有关,当化学配比为Y0.2Gd1.65Eu0.15O3时样品发光强度最高,y值超过0．15会发生浓度猝灭,导致发光强度降低．     

不同晶粒尺寸的(La0.47Gd0.2)Sr0.33MnO3纳米颗粒磁性能

采用非晶态多核配合的方法制备了(La0.47Gd0.2)Sr0.33MnO3纳米颗粒,用XRD、HRTEM和MPMS等手段对纳米颗粒的微观结构和磁性能进行研究。XRD和SAD分析表明,所有的样品都具有单相钙钛矿结构;TEM分析表明, 经过600,800和1000 ℃烧结10 h后的样品颗粒尺寸分别为40~50 nm,90~100 nm和140~150 nm。样品的磁学性能结果表明：(La0.47Gd0.2)Sr0.33MnO3纳米颗粒的居里温度TC (298 K)基本上不随颗粒尺寸的变化而变化,而相对磁制冷能力取决于颗粒尺寸;颗粒尺寸为90~100 nm的(La0.47Gd0.2)Sr0.33MnO3纳米颗粒的相对磁制冷能力最大,可以作为室温下使用的磁制冷工质侯选材料。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.