A pilot experiment for mass measurement at CSRe

A pilot experiment of mass measurement was performed at CSRe with the method of isochronous mass spectrometry. The secondary fragments produced via RIBLL2 with the primary beam of 400 MeV/u ^36Ar delivered by CSRm were injected into CSRe. The revolution periods of the stored ions,which depend on the mass-to-charge ratios of the stored ions,were measured with a time-of-flight detector system. The results show that the mass resolution around 8×10^-6 for △m/m is achieved.     

Integrable Couplings of Classical-Boussinesq Hierarchy and Its Hamiltonian Structure＊

By using a Lie algebra, an integrable couplings of the classicai-Boussinesq hierarchy is obtained. Then, the Hamiltonian structure of the integrable couplings of the classical-Boussinesq is obtained by the quadratic-form identity.     

Multi-component Levi Hierarchy and Its Multi-component Integrable Coupling System

A simple 3M-dimensional loop algebra X is produced, whose commutation operation defined by us is A1 as simple and straightforward as that in the loop algebra A1. It follows that a general scheme for generating multi-component integrable hierarchy is proposed. By taking advantage of X, a new isospectral problem is established, and then by making use of the Tu scheme the well-known multi-component Levi hierarchy is obtained. Finally, an expanding loop algebra FM of the loop algebra .X is presented, based on the FM, the multi-component integrable coupling system of the multi-component Levi hierarchy is worked out. The method in this paper can be applied to other nonlinear evolution equation hierarchies.     

Color improvement of white-light through Mn-enhancing yellow-green emission of SrSi2O2N2:Eu phosphor for white light emitting diodes

Photoluminescence (PL) enhancement of SrSi₂O₂N₂:Eu and the resultant color improvement of white-light were investigated via co-doping Mn with Eu. We observed that a unique absorption of host lattice of SrSi₂O₂N₂ and its visible band emission peaked at around ∼550 nm for SrSi₂O₂N₂:Mn²⁺ in the wavelength range of 450-600 nm. This highly eye-sensitive ∼550 nm-peaked band emission of SrSi₂O₂N₂ doped with Mn²⁺ happens to overlap the 535 nm-peaked band emission of SrSi₂O₂N₂ doped with Eu²⁺, resulting in an intensified photoluminescence in a maximum by 355%. By combining this as-prepared Mn intensified SrSi₂O₂N₂:Eu phosphor with blue InGaN chip, the quality of white-light was improved to 93.3% for color rendering index and 3584 K for correlated color temperature.     

Atomic origins of solid helium bubbles in tungsten

Solid helium bubbles were directly observed in the helium ion implanted tungsten（W）, by different transmission electron microscopy（TEM） techniques at room temperature. The diameters of these solid helium bubbles range from1 nm to 8 nm in diameter with the mean bubble size about 3 nm. The selected area electron diffraction（SAED） and fast Fourier transform（FFT） images revealed that solid helium bubbles possess body-centered cubic（bcc） structure with a lattice constant of 0.447 nm. High-angle annular dark-field scanning transmission electron microscopy（HAADF-STEM）images further confirmed the existence of helium bubble in tungsten. The present findings provide an atomic level view of the microstructure evolution of helium in the materials, and revealed the existence of solid helium bubbles in materials.     

Experimental and Theoretical Investigation of Valence Orbitals in 1,4-Dioxane by Electron momentum Spectroscopy

The binding energy spectrum of all valence orbitals and the momentum distributions of highest occupied molecular orbital （HOMO： 8ag）, 7bu＋7ag, 4bu, 2bg ＋4ag and 2au in 1, 4-dioxane are investigated by electron momentum spectroscopy （EMS） with 600 eV impact energy. The experimental results are consistent with theoretical calcula- tions of C2h chair conformation using the Hartree-Fock method and density functional theory with 6-311＋＋G^＊＊ and AUG-CC-PVTZ basis sets.     

Spontaneous emission coupling factors in planar micro-cavity lasers with distributed Bragg reflectors

In this article, a considerable value of spontaneous emission factor is estimated based on the spontaneous emission radiation patterns in micro-cavity lasers. After the spontaneous emission for a dipole in the micro-cavity is studied, the confinements of vacuum fields and electrons are considered together for a quantum well in the micro-cavity laser. The TE mode and TM mode spontaneous emission spectra are presented for a single quantum well embedded in a planar micro-cavity laser at 300 K. The results show that the TE mode spontaneous emission spectrum is enhanced, whereas the TM mode spontaneous emission is suppressed greatly. The maximum values obtained for the spontaneous emission coupling factors are 0.2 and 0.0055 for a dipole and a quantum well planar micro-cavity laser with distributed Bragg reflectors, respectively.     

γ-AlON晶体电子结构和光学性质研究

本研究在基于第一性原理的密度泛函理论(DFT)框架下, 采用局域密度近似(LDA)和赝势平面波方法, 计算了平衡结构尖晶石型γ -AlON的态密度和光学性质参数．结合表征电子结构的态密度, 分析了γ -AlON在0—30 eV范围内的复介电函数以及由其导出的折射率、反射谱、 吸收谱等．理论计算得出: γ -AlON零频介电常数ε₁(0)=2.60, 折射率n₀=1.61, 在红外到近紫外以及20.23 eV以上的紫外波段,其光吸收趋近于零, 表现为光学透明. 理论计算结果与相关实验数据相一致, 为γ -AlON在光学窗口及头罩材料等方面的应用提供了理论依据和参考.     

多孔脆性材料对高能量密度脉冲的吸收和抵抗能力

作用在脆性结构材料表面的高能量密度脉冲会以冲击波的形式传播进入材料内部, 导致压缩破坏和功能失效. 通过设计并引入微孔洞, 显著增强了脆性材料冲击下的塑性变形能力, 从而使脆性结构材料可以有效地吸收耗散冲击波能量, 并抑制冲击诱导裂纹的扩展贯通. 建立格点-弹簧模型并用于模拟研究致密和多孔脆性材料在高能量密度脉冲加载下的冲击塑性机理、能量吸收耗散过程和裂纹扩展过程. 冲击波压缩下孔洞塌缩, 导致体积收缩变形和滑移以及转动变形, 使得多孔脆性材料表现出显著的冲击塑性. 对致密样品、气孔率5%和10%的多孔样品吸能能力的计算表明, 多孔脆性材料吸收耗散高能量密度脉冲的能力远优于致密脆性材料. 在短脉冲加载下, 相较于遭受整体破坏的致密脆性材料, 多孔脆性材料以增加局部区域的损伤程度为代价, 阻止了严重的冲击破坏扩展贯通整个样品, 避免了材料的整体功能失效.