First-Principles Calculations for Thermodynamic Properties of Perovskite-Type Superconductor MgCNi3

The ground state properties and equation of state of the non-oxide perovstdte-type superconductor MgCNi3 are investigated by first-principles calculations based on the plane-wave basis set with the local density approximation （LDA） as well as the generalized gradient approximation （GGA） for exchange and correlation, which agree well with both theoretical calculations and experiments. Some thermodynamic properties including the heat capacity, the thermal expansion coefficient and the Griineisen parameter for perovskite structure MgCNi3 are obtained. The dependences of these thermodynamic properties on pressure and temperature are given for the first time.     

A Kind of Exact Inflationary Solution in the Chaotic Inflation Model to Non-minimally Coupled Scalar Field

We present a kind of exact inflationary solution in the chaotic inflation scenario to non-minimal coupled scalar field, taking the Hubble parameter directly as a function of the scalar field φ, H（φ） = αφ^n. Using the analysis of the WMAP3 data, we give the range of power index n.     

Self-Injection and Acceleration of Monoenergetic Electron Beams from Laser Wakefield Accelerators in a Highly Relativistic Regime

Self-injection and acceleration of monoenergetic electron beams from laser wakefield accelerators are first investigated in the highly relativistic regime, using 100 TW class, 27 fs laser pulses. Quasi-monoenergetic multi- bunched beams with energies as high as multi-hundredMeV are observed with simultaneous measurements of side-scattering emissions that indicate the formation of self-channelfing and self-injection of electrons into a plasma wake, referred to as a ＇bubble＇. The three-dimensional particle-in-cell simulations confirmed multiple self-injection of electron bunches into the bubble and their beam acceleration with gradient of 1.5 GeV/cm.     

Common Features in Electronic Structure of the Oxypnictide Superconductors from Photoemission Spectroscopy

High resolution photoemission measurements are carried out on non-superconducting LaFeAsO parent com- pound and various superconducting RFeAs（O1-ZFx） （R=La, Ce and Pr） compounds. It is found that the parent LaFeAsO compound shows a metallic character. By extensive measurements, several common features are identified in the electronic structure of these Fe-based compounds： （1） 0.2 eV feature in the valence band, （2） a universal 13-16 meV feature, （3） near EF spectral weight suppression with decreasing temperature. These uni- versal features can provide important information about band structure, superconducting gap and pseudogap in these Fe-based materials.     

锰位铁掺杂La0.67Sr0.33FexMn1-xO3薄膜的光诱导效应

分别采用溶胶-凝胶法和脉冲激光沉积的方法制备了La_067Sr_033Fe_xMn_1-xO₃(x=0, 005, 010, 015)系列块材和薄膜,研究了Fe部分替代对La_067Sr_033Fe_xMn_1-xO₃薄膜 关键词： 光诱导 Fｅ掺杂 晶格效应     

层状钙钛矿La1.3Sr1.7Mn2-xCuxO7的磁性及电特性

通过固相反应烧结法成功制备了层状钙钛矿La1.3Sr1.7Mn2-xCuxO7多晶,主要研究了其磁电特性.结果表明,样品为Sr3Ti2O7型钙钛矿结构.随着温度的降低,其磁性经历了一个很复杂的转变过程.当x=0时,在T*=231 K出现二维短程铁磁有序,在Tc=114 K出现三维长程铁磁有序,在TN=56 K出现倾斜的反铁磁转变.当x=0.05时,Cu替代使得T*,Tc和TN减小.其电特性表明,La1.3Sr1.7Mn2-xCuxO7多晶呈现出双峰现象,这是由于钙钛矿结构锰氧化物共生现象造成的.虽然5%Cu替代,降低了金属一绝缘体转变温度,但是却增强了磁电阻效应.     

超薄层BCP对有机电致发光器件性能的影响

采用真空热蒸镀的方法,在常规的双层器件结构的基础上,设计了三层双异质结有机电致发光器件(OLED):indium-tin oxide(ITO)/N,N′-diphenyl-N,N′-bis(1-naphthyl)(1,1′-biphenyl)-4,4′-diamine(NPB)/2,9-dimethyl-4,7-diphenyl-1,10-phenan throline(BCP)/8-hydroxyquinoline aluminum(Alq3)/Mg∶Ag。通过对器件的电致发光(EL)光谱及器件性能的表征,研究了不同超薄层BCP的厚度对OLED器件性能的影响。结果表明,当超薄层BCP的厚度从0.1nm逐渐增加到4.0nm时,器件的EL光谱实现了绿光→蓝绿光→蓝光的变化;BCP层有效地调节了载流子的复合区域,改变了器件的发光颜色,提高了器件的亮度和发光效率。     

柔性有机电致发光器件导电基板的工艺性能

在聚对苯二甲酸乙二醇酯(PET)柔性衬底上采用直流磁控溅射技术制备了氧化铟锡(ITO)透明导电薄膜,研究了衬底温度、溅射功率和溅射压强等工艺条件对薄膜光电性能的影响,并利用原子力显微镜(AFM)表征了衬底及ITO薄膜的表面形貌。结果表明,在PET衬底温度50℃、溅射功率100W和溅射压强2.66×10-1Pa的条件下,可以得到低方阻(50Ω/□)和高透过率(>90%)的透明导电薄膜。以此柔性ITO衬底为阳极,制备了结构为PET/ITO/NPB/Alq3/Mg∶Ag的柔性有机电致发光器件,在驱动电压为13V时,器件的发光亮度达到了2834cd/m2。     

Spectral Characteristics of White Organic Light-emitting Diodes Based on Novel Phosphorescent Sensitizer

采用新型贵金属铱的配合物bis(1,2-dipheny1-1H-benzoimida-zole)iridium (acetylacetonate)作为磷光敏化剂,与荧光染料4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-en-yl)-4H-pyran共同掺杂到聚合物主体材料poly(N-vinylcarbazole)中,以N,N'-diphenyl-N,N'-bis(1-naphthyl) (1,1'-biphenyl)-4,4'-diami-ne作为蓝光发光层,制备了白色有机电致发光器件. 通过对掺杂体系的紫外-可见吸收光谱、光致发光光谱以及电致发光光谱的表征,分析了该磷光敏化体系的能量转移机制. 结果表明,在该聚合物磷光荧光双掺杂体系中,由于磷光与荧光材料之间的不完全的F?rster能量传递过程,导致电致发光光谱中同时存在磷光材料三线态到基态与荧光材料单线态到基态的辐射衰减发光. 该掺杂体系成功实现了白光发射,随着偏置电压的升高,器件的CIE色坐标有微小的红移,但都非常接近等能白光点,器件表现出了很好的色纯度.     

激光靶心冲击波观测镜折反式光学系统设计

设计了一种激光靶心冲击波观测镜的光学系统.用反射式光学系统代替折射式光学系统,解决了普通玻璃在200 nm端透过率较低的问题.反射镜不引入色差,有利于系统在200~800 nm谱段消色差.为消系统轴外像差,反射系统选型为对称式.反射镜全部采用球面镜,为消反射镜以及平板玻璃窗带入的球差,引入校正镜(材料JGS1),在满足要求的条件下,控制折射镜的厚度,使系统色差满足瑞利判据的色差允差,得到了良好的成像质量.