绿色荧光粉YAGG∶Tb,Gd用于FED的尝试

FED器件的发展迫切需要具有化学和热稳定性 ,高亮度 ,长寿命的新型荧光材料。本文合成了Gd3 +离子共掺杂的YAGG∶Tb获得了YAGG∶Tb ,Gd ,并将其用于 0～ 30 0 0V低压范围 ,对其在不同电压和电流密度下的发光特性进行了测试。结果表明 ,该种材料特性优于ZnO∶Zn并且不存在电压与电流饱和     

A polynomial approximation for the scattering wavefunction of an arbitrary spherically symmetric potential

A new variational approach is proposed to calculate scattering phase shifts.In this approach,the variational parameter is contained not explicitly in the trial function but in the boundary conditions that the scattering wavefunction should satisfy.It was found that a high accuracy could be reached.Furthermore,the scattering wavefunction appears as a polynomial of finite orders in the interior region.This expression is convenient for applications.     

A design of novel type superconducting magnet for super—high field functional magnetic resonance imaging by using the harmonic analysis method of magnetic vector potentials

The approach of expanding the magnetic scalar potential in a series of Legendre polynomials is suitable for designing a conventional superconducting magnetic resonance imaging magnet of distributed solenoidal configuration. Whereas the approach of expanding the magnetic vector potential in associated Legendre harmonics is suitable for designing a single-solenoid magnet that has multiple tiers, in which each tier may have multiple layers with different winding lengths. A set of three equations to suppress some of the lowest higher-order harmonics is found. As an example, a 4T single-solenoid magnetic resonance imaging magnet with 4×6 layers of superconducting wires is designed. The degree of homogeneity in the 0.5m diameter sphere volume is better than 5.8 ppm. The same degree of homogeneity is retained after optimal integralization of turns in each correction layer. The ratio B_m/B₀ in the single-solenoid magnet is 30% lower than that in the conventional six-solenoid magnet. This tolerates higher rated superconducting current in the coil. The Lorentz force of the coil in the single-solenoid system is also much lower than in the six-solenoid system. This novel type of magnet possesses significant advantage over conventional magnets, especially when used as a super-high field functional magnetic resonance imaging magnet.     

KNSBN晶体猫式互抽动相位共轭光特性

在KNSBN：Ce晶体中，利用二波耦合作用，在单一光束无法获得相位共轭光的条件下，实现了“猫”式互抽运相位共轭光输出，获得较高的共轭光发射率，实验结果表明，晶体的二波耦合作用可以使晶体的自抽运相位共轭光的阈值光强降低。入射光的入射角范围增大，响应时间缩短。     

声纳方程的瞬态形式讨论

本文提出用瞬态信号的能谱级代替稳态信号的声强级来定义声纳参数，并以短柱声散射为例，运用数值模拟方法，验证用能谱级定义声纳参数，声纳方程是比较有效的，这为应用声纳方程处理瞬态声信号从而获得目标强度提供了一种有效可行的方法。     

工作点测量系统在合肥光源的应用研究

 介绍了利用合肥光源(HLS)的工作点测量系统进行一些束流参数的测量及其应用研究，这些参数包括工作点、β函数；自然色品以及中心频率。同时还进行了清洗电极对工作点的影响的测量。给出了一些测量结果，测量结果与理论计算值相当吻合。     

Facile synthesis of SnO2–ZnO core–shell nanowires for enhanced ethanol-sensing performance

The design of core–shell heteronanostructures is powerful tool to control both the gas selectivity and the sensitivity due to their hybrid properties. In this work, the SnO₂–ZnO core–shell nanowires (NWs) were fabricated via two-step process comprising the thermal evaporation of the single crystalline SnO₂ NWs core and the spray-coating of the grainy polycrystalline ZnO shell for enhanced ethanol sensing performance. The as-obtained products were investigated by X-ray diffraction, scanning electron microscopy, and photoluminescence. The ethanol gas-sensing properties of pristine SnO₂ and ZnO–SnO₂ core–shell NW sensors were studied and compared. The gas response to 500 ppm ethanol of the core–shell NW sensor increased to 33.84, which was 12.5-fold higher than that of the pristine SnO₂ NW sensor. The selectivity of the core–shell NW sensor also improved. The response to 100 ppm ethanol was about 14.1, whereas the response to 100 ppm liquefied petroleum gas, NH₃, H₂, and CO was smaller, and ranged from 2.5 to 5.3. This indicates that the core–shell heterostructures have great potential for use as gas sensing materials.     

Randall-sundrum brane model with 7D anti-de sitter space

In the same sense that 5D anti-de Sitter space (AdS(5)) warped geometries arise naturally from type IIB string theory with stacks of D3 branes, AdS(7) warped geometries arise naturally from M theory with stacks of M5 branes. We compactify two spatial dimensions of AdS(7) to get AdS(5) x Sigma(2), where the metric for Sigma(2) inherits the same warp factor as appears in the AdS(5). We analyze the 5D spectrum in detail for the case of a bulk scalar or a graviton in AdS(5) x T(2), in a setup which mimics the first Randall-Sundrum model. The results display novel features which might be observed in experiments at the CERN Large Hadron Collider. For example, we obtain TeV scale string winding states without lowering the string scale. This is due to the double warping which is a generic feature of winding states along compactified AdS directions. Experimental verification of these signatures of AdS(7) could be interpreted as direct evidence for M theory.     

中子诱发233,235,238U裂变机制的多通道理论研究

用改进的多通道和无规颈断裂模型,计算了能量E_n=0—6MeV的中子诱发²³³U、²³⁵U裂变和E_n=1.3—5.3MeV中子诱发²³⁸U裂变的碎片的质量分布、动能分布和瞬发中子数分布,理论计算在定量上与实验符合较好.