Ultra-incompressible Ternary Diborides Re_（0.5）Ir_（0.5）B_2,Re_（0.5）Tc_（0.5）B_2,Os_（0.5）W_（0.5）B_2 and Os_（0.5）Ru_（0.5）B_2：Density Functional Calculation

In this paper, density functional computations have been applied to the structural, elastic and electronic properties of ternary transition metal diborides Re0.5Ir0.5B2, Re0.5Tc0.5B2, Os0.5W0.5B2 and Os0.5Ru0.5B2 in hexagonal (P63/mmc) and orthorhombic (Pmmn) structures with both local density approximation and generalized gradient approximation. LDA gives smaller lattice parameters and larger elastic moduli than GGA. Both results show that the hexagonal ones are more stable than orthorhombic ones except Os0.5Ru0.5B2. Moreover, the hexagonal structure has superior elastic property than orthorhombic one. Generally speaking, the calculated elastic moduli of Re0.5Ir0.5B2 and Os0.5Ru0.5B2 are smaller than those values of Re0.5Tc0.5B2 and Os0.5W0.5B2 within the same structure because of the filling of antibonding states. The relativistic effects result in weaker bonds of Tc-B (Ru-B) than those of Re-B (Os-B). All the diborides are ultra-incompressible. Re0.5Tc0.5B2 has the largest shear modulus and it is a promising superhard diboride like Os0.5W0.5B2. The elastic properties are in high correlation with the bond strength. The shear moduli are more sensitive than the bulk moduli to the bond strength.     

稀土取代的复合氧化物Eu_（0．5）RE_（0．5）Fe_（0．5）Mn_（0．

利用固相反应合成了稀土取代的复合氧化物Ｅｕ_（０．５）ＲＥ_（０．５）Ｆｅ_（０．５）Ｍｎ_（０．５）Ｏ_３（ＲＥ＝Ｌａ，Ｐｒ，Ｎｄ，Ｓｍ，Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ）．测量了这些化合物的ＸＲＤ和ＸＰＳ谱。在ＸＰＳ研究中发现，稀土取代而使稀土元素本身的结合能相对于其倍半氧化物中的有所降低；在取代的复合氧化物中，随着ＲＥ离子半径的减小，Ｆｅ、Ｍｎ的结合能随之增加。     

La_(0.5)Na_(0.5)TiO_3纳米晶的制备及光致发光研究

以硬脂酸、硝酸镧、氢氧化钠和钛酸四丁酯为原料制备了La0 .5Na0 .5TiO3 纳米晶 ,粒度最小可达 1 4nm ,烧成温度为 50 0℃ ,低于传统固相反应的合成温度。光致发光研究表明 :用 392nm光作激发光 ,在室温下观察到了一个强的蓝光发射带 ,并且它的强度和半宽度随粒度发生明显变化。     

Phase separation and superconductivity in Fe(1+x)Te(0.5)Se(0.5)

Fe(1+x)Te(0.5)Se(0.5) is the archetypical iron-based superconductor. Here we show that the superconducting state is controlled by the stacking of its anti-PbO layers, such that homogeneous ordering hinders superconductivity and the highest volume fractions are observed in phase separated structures as evidenced by either a distribution of lattice parameters or microstrain.     

Sm_(0.5)Sr_(0.5)CoO_3阴极氧还原动力学

利用极化、交流阻抗技术考察了担载于La0.9Sr0.1Ga0.8Mg0.2O3(LSGM)电解质上的Sm0.5Sr0.5CoO3-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(SSC-LSGMC5)复合阴极的氧还原反应动力学.在SSC-LSGMC5阴极氧还原反应的阻抗谱中可以观察到明显的两个半圆.高频环的电导与氧分压无关,低频环的电导正比于氧分压的0.5次方.并且低频环的氧分压级数随着反应温度的降低而减小,可能对应于吸附氧原子的扩散过程.SSC-LSGMC5极化曲线与经典的Butler-Volmer方程吻合.阴、阳极的电荷转移系数均为1左右,交换电流密度的氧分压级数为1/4,对应于电荷转移过程.实验结果显示SSC-LSGMC5上的氧还原反应机制随反应条件的不同而发生变化.     

Zr0.5Ti0.5O2纳米薄膜的光电性能

采用溶胶-凝胶法制备了Zr0.5Ti0.5O2固溶体薄膜,通过X-射线衍射分析（XRD）、扫描电镜分析（SEM）、紫外吸收光谱(UV-Vis)和X射线光电子能谱（XPS）等方式对材料进行了表征。结果表明实验制得的材料Zr：Ti=1:1,薄膜表面平整、致密、光滑,皲裂情况较单纯的TiO2和ZrO2薄膜有明显改进;另外由于Zr的掺入,薄膜在紫外光波段有良好的吸收,吸收边较TiO2薄膜有明显的蓝移。通过标准的光刻剥离技术和磁控溅射技术在Zr0.5Ti0.5O2纳米薄膜上制作了叉指型的金属电极。在5V偏压下,样品对可见光不吸收,对260 nm的紫外光有明显的光电响应,光电流与暗电流之比近3个数量级。     

KTa_(0.5)Nb_(0.5)O_3电子结构的第一性原理研究

用全电势线性缀加平面波法 (FLAPW )计算了KTa0 .5Nb0 .5O3 铁电相和顺电相的态密度、能带结构 .通过对两相态密度的对比分析我们发现在铁电相 ,钽原子的d电子和氧原子的 2p电子以及铌原子d电子与氧原子的 2p电子之间存在强烈的轨道杂化 ,对能带的分析也得出同样的结论 .这种轨道杂化对KTa0 .5Nb0 .5O3 铁电性的稳定有着重要的意义 .钽原子在四方铁电体KTa1 xNbxO3 中的作用与在纯钽酸钾中的作用有明显的差别 .     

K-Ce_(0.5)Zr_(0.5)O_2催化碳颗粒物燃烧性能

用等体积浸渍法制备了不同K负载量的xKNO3-Ce0.5Zr0.5O2系列催化剂,用程序升温氧化反应(TPO)考察催化剂对碳颗粒物(soot)燃烧的催化活性.并采用XRD、BET、FT-IR、XPS等技术对KNO3负载催化剂进行表征.结果表明KNO3负载量对催化剂的比表面、表面化学环境有显著的影响;KNO3能使催化剂对soot的催化燃烧活性有较大提高,且存在最佳负载量,当x=0.5时,催化剂的活性最好,碳颗粒物的起燃温度(T)i和峰顶温度(Tp)分别为290℃和360℃.在反应过程中,KNO3熔融状态的形成和K2CO3的生成,使催化活性明显提高.     

局部化学法合成K0.5Bi0.5TiO3片状晶粒及其反应机理研究

以含铋层状Bi4Ti3O12(BIT)晶粒作为反应前驱体, 通过熔盐环境下的局部化学反应法制备了片状钛酸铋钾(K0.5Bi0.5TiO3, KBT)陶瓷粉体晶粒. 分析结果表明, 所制备的KBT陶瓷晶粒平均直径约为15～20 μm, 厚度小于2 μm. 分析了由含铋层状型BIT向钙钛矿型KBT片晶转化的形成机制, 并讨论了反应路径对最终产物形貌的影响规律.     

KTa_(0.5)Nb_(0.5)O_3电子结构的第一性原理研究

用全电势线性缀加平面波法（FLAPW）计算了KTa_(0.5)Nb_(0.5)O_3铁电相和 顺电相的态密度、能带结构。通过对两相态密度的对比分析我们发现在铁电相，钽 原子的d电子和氧原子的2p电子以及铌原子d电子与氧原子的2p电子之间存在强烈的 轨道杂化，对能带的分析也得出同样的结论。这种轨道杂化对KTa_(0.5)Nb_(0.5) O_3铁电性的稳定有着重要的意义。钽原子在四方铁电体KTa_(1-x)Nb_xO_3中的作 用与在纯钽酸钾中的作用有明显的差别。     

铕镧共掺稀土配合物Eu0.5La0.5(TTA)3phen与PVK共混体系发光特性的研究

合成了一种新型的稀土铕配合物Eu0.5La0.5(TTA)3phen,把它作为发光材料应用于有机电致发光中.把铕配合物与高分子导电聚合物共混制得混合溶液,然后用旋涂的方法制得了发光层.实验中制备了单层、双层器件,讨论了器件的优化条件,并用能级图探讨了Eu0.5La0.5(TTA)3phen与PVK共混体系光致、电致发光的能量传递机制.优化后的双层器件,开启电压为6.5 V,在电压12.5 V,电流密度为68.48 mA*cm-2时器件达到最大亮度238.4 cd·m-2,发光效率0.35 cd·A-1.     

PAni-Co0.5Zn0.5Nd0.05Fe1.95O4纳米复合材料的制备及电磁损耗

采用原位聚合法制备了平均粒径约为80 nm的聚苯胺(Polyaniline, PAni)-Co0.5Zn0.5Nd0.05Fe1.95O4纳米复合材料. 采用X射线衍射仪(XRD)、透射电子显微镜(TEM)和傅里叶变换红外光谱(FTIR)等检测技术对其结构、形貌、电磁及微波吸收性能进行了研究. 结果表明, 在12.4~18.0 GHz测试频率范围内, 复合材料的介电损耗角正切(tanε)在0.22~0.34之间, 磁损耗角正切(tanμ)在0.27~0.35之间. 在频率为9.5 GHz处, 反射损耗达到最大值-7.31×10-29 C·m, 频带宽为4.5 GHz.     

Precisely Composition Controlled Synthesis of Cu_(0.5)Ni_(0.5) Alloy with Optimum Catalytic Activity

Alloys based on non-noble metals could be the next generation of high-performance catalysts for many chemical reactions. However, precisely composition controlled synthesis of non-noble alloys remains a significant challenge. In this work, we report a simple synthesis of Cu_(0.5)Ni_(0.5) alloys without any component segregation. Its success relies on the use of Cu–Ni oxalate precursors, which are chelated in the proximity by oxalate ligands. One of the attractive features for the oxalate routes of catalyst preparation is that no classical support material is needed. The actual component ratios of the obtained Cu_(0.5)Ni_(0.5) alloy are consistent with the initial ratio. Cu_(0.5)Ni_(0.5) alloy shows a higher catalytic activity than pure Cu and Ni catalysts in the reduction of p-nitrophenol(4-NP) to p-aminophenol(4-AP) by sodium borohydride(NaBH4) in an aqueous solution, and the performance depends strongly on the strong interaction between Cu and Ni. The findings reported here are highly helpful to understand the relationship between the synergistic effects in alloys and their catalytic performance, and therefore could provide appropriate strategies to obtain desirable catalysts with improved activity in various catalytic applications.     

Room temperature antiferromagnetic order in the Mn(II) Oxide 4H-Ba(0.5)Sr(0.5)MnO(2+delta)

The synthesis of the Mn(II) phase 4H-Ba(0.5)Sr(0.5)MnO(2+delta) via the topotactic reduction of 4H-Ba(0.5)Sr(0.5)MnO(3-x) with the novel reducing agent LiH, is described. Neutron powder diffraction data show that oxide ions are deintercalated from the host structure in a disordered manner to yield "tetrahedral" MnO(4) coordination sites. Magnetic susceptibility and neutron powder diffraction data show that the title phase adopts a canted antiferromagnetically ordered state below T(N) = 355K, consistent with the strong magnetic coupling expected between d(5) centers.     

Open-framework Borophosphate:(NH4)0.5FeⅡ0.5FeⅢ0.5·(H2O)2 BP2O8·0.5 H2O

An open-framework ammonium ferricborophosphate compound was synthesized by mild hydrothermal condition at 110°C. The crystal structure has been determined by single-crystal X-ray diffraction analysis: hexagonal, P6522, a = 9.452(2)A, c = 15.698(5)A,α = 90°,γ = 120°,Z= 6, Mr = 310.58, V = 1214.0(5)A3, Dc = 2.549 g/cm3, μ= 2.311mm-1, F(000) = 930. The chiral tetrahedral-tetrahedral helical ribbons are linked by the mixed valance FeII/FeIIIO6 coordinated octahedra. The ammonium ions are located inside the free loop of helical ribbons close to the inner wall of the helical channels{[BP2O8]3-}, effecting on balancing charge and stabilizing helical ribbons.     

Li0.5-0.5xZnxFe2.5-0.5xO4纳米纤维的电纺制备及其结构和磁性能

以聚乙烯吡咯烷酮、硝酸锂、硝酸锌和硝酸铁为主要原料,通过静电纺丝技术结合后期的热处理制备了直径在50～100 nm的单相Li0.5-0.5xZnxFe2.5-0.5xO4（x=0.0,0.2,0.3,0.4,0.5,0.8）纳米纤维.利用热重-差热分析、X射线衍射、场发射扫描电子显微镜、透射电子显微镜和振动样品磁强计研...     

由钯纳米溶胶制备Pd/Ce_(0.5)Zr_(0.5)O_2催化剂及其表征研究

采用超声膜扩散还原法制备出金属Pd纳米溶胶,然后从Pd纳米溶胶出发,采用不同方法制备出系列纳米Pd/Ce0.5Zr0.5O2催化剂。采用TEM观察Pd纳米粒子的形貌,采用N2吸/脱附,XRD,TPR和ICP对Pd/Ce0.5Zr0.5O2催化剂进行表征,并考察比较了各催化剂对CO+O2的催化活性差别,结果表明:先制备Pd纳米溶胶,再负载于载体上的方法制得的催化剂金属负载量较低,但是其活性最高,CO在150℃就能完全转化,金属分散度较高,活性Pd物种还原温度低,催化剂的CO低温活性与H2还原温度和金属分散度有关。这种催化剂制备方法为在提高催化剂活性的同时降低贵金属用量提供了可能。     

SIMOX上分子束外延生长Si／Ge0.5Si0.5应变层超晶格的TEM研究

以分子束外延技术在ＳＩＭＯＸ衬底上生长Ｓｉ／Ｇｅ_（０．５）Ｓｉ_（０．５）应变层超晶格。用剖面电子显微学（ＸＴＥＭ）对超晶格膜的结构进行分析。实验结果表明，Ｓｉ／Ｇｅ_（０．５）Ｓｉ_（０．５）应变层超晶格能成功地生长在ＳＩＭＯＸ衬底上。由于Ｓｉ／Ｇｅ_（０．５）Ｓｉ_（０．５）膜与ＳＩＭＯＸ衬底之间的晶格失配，引起晶格畸变，Ｓｉ／Ｇｅ_（０．５）Ｓｉ_（０．５）超晶格内存在的位错与ＳＩＭＯＸ衬底内的位错密度有关。     

Magnetoelectric perovskite (Bi0.5Pb0.5)(Fe0.5Zr0.5)O3: Preparation,structural and magnetic properties

The perovskite (Bi_0.5Pb_0.5)(Fe_0.5Zr_0.5)O₃ was synthesized by solid-state reaction in an attempt to find magnetoelectric materials, in which ferroelectricity and ferromagnetism coexist. This complex perovskite has been studied by X-ray and neutron powder diffraction in combination with magnetic measurements. The compound crystallizes in the orthorhombic space group Pbam with a ～ √2a_p, b ～ 2√2a_p and c ～ 2a_p (with a_p ～ 4.057 Å). The field and temperature dependence of the magnetization combined with neutron diffraction data showed antiferromagnetic behavior with the Neel temperature, T_N ～ 450 K. Rietveld refinements of neutron powder diffraction data collected at different temperatures, between 10 and 700 K, have been carried out in order to extract information about the thermal evolution of the nuclear and magnetic structures. A distorted orthorhombic perovskite structure was found within the whole temperature interval. The Bi/Pb and Fe/Zr ions were found to be partially ordered over the perovskite A-site and disordered over the B-site. The neutron diffraction patterns of the (Bi_0.5Pb_0.5)(Fe_0.5Zr_0.5)O₃ sample showed evidence of a long-range magnetic ordering below T_N with a propagation vector k = (0,0,0) and an antiferromagnetic arrangement of the magnetic moments of the Fe³⁺ cations in the B-site. This is consistent with an A_y-type magnetic structure. The factors governing the structural and magnetic properties of (1 ? x)BiFeO₃–xPbZrO₃ solid solutions are discussed and compared with those of pure BiFeO₃ and PbZrO₃. A solid solution strategy for developing magnetoelectric properties in BiFeO₃-based compounds is described, with the aim of realizing both a spontaneous polarization and magnetization at room temperature.