蓝宝石光纤端面上ZnO薄膜的制备及其温变光学特性

介绍了利用电子束蒸发技术在蓝宝石光纤端面上生长具有良好表面形貌和晶体结构的ZnO薄膜方法.不同测试温度（室温至773 K）条件下的透射光谱显示,蒸镀在蓝宝石光纤端面上的ZnO薄膜,其光学吸收边随温度升高而发生红移现象,且禁带宽度和热力学温度之间满足E_g（T）=340-491×10^-4T的关系.这为今后进一步利用ZnO薄膜的禁带宽度检测相应的环境温度,研制以ZnO薄膜为敏感材料的新型宽量程光纤温度传感器打下了良好的基础. 关键词： ZnO薄膜 蓝宝石光纤 光学吸收边 光纤温度传感器     

白宝石衬底上生长的MgxZn1-xO晶体薄膜的结构和光学性能

在白宝石（sapphire）衬底上低温外延生长出了Mg_xZn_1-xO晶体薄膜.x射线衍射（XRD）及能量色散x射线（EDX）分析表明，Mg_xZn_1-xO薄膜的晶体结构依赖于薄膜中Mg的组分x，随着Mg组分的增大，Mg_xZn_1-xO薄膜的结构从与ZnO晶体一致的六方结构转变为与MgO晶体一致的立方结构.对Mg_xZn_1-xO薄膜的紫外透 关键词： 电子束蒸发反应 xZn_1-xO晶体薄膜')" href="#">Mg_xZn_1-xO晶体薄膜 结构和光学性能     

Towards understanding astrophysical effects of nuclear symmetry energy

The European Physical Journal A - The properties of the quantum electrodynamic (QED) vacuum in general, and of the nuclear vacuum (ground) state in particular, are determined by virtual processes...     

Relation between gravitational mass and baryonic mass for non-rotating and rapidly rotating neutron stars

With a selected sample of neutron star(NS)equations of state(EOSs)that are consistent with the current observations and have a range of maximum masses,we investigate the relations between NS gravitational mass Mg and baryonic mass and the relations between the maximum NS mass supported through uniform rotation(Mmax)and that of nonrotating NSs(Mtov).We find that for an EOS-independent quadratic,universal transformation formula(Mb=Mg+A×M^2/g),the best-fit A value is 0.080 for non-rotating NSs,0.064 for maximally rotating NSs,and 0.073 when NSs with arbitrary rotation are considered.The residual error of the transformation is?0.1M⊙ for non-spin or maximum-spin,but is as large as?0.2M⊙ for all spins.For different EOSs,we find that the parameter A for non-rotating NSs is proportional to R^-1/1.4(where R1.4 is NS radius for 1.4M⊙ in units of km).For a particular EOS,if one adopts the best-fit parameters for different spin periods,the residual error of the transformation is smaller,which is of the order of O.O1M⊙ for the quadratic form and less than O.O1M⊙ for the cubic form(Mb=Mg+A1×M^2/g+A2×M^3/g).We also find a very tight and general correlation between the normalized mass gain due to spin △m≡(Mmax-MTOV)MTOV and the spin period normalized to the Keplerian period P,i.e.,log10 △m=(-2.74±0.05)log10 P+log10(0.20±0.01),which is independent of EOS models.These empirical relations are helpful to study NS-NS mergers with a long-lived NS merger product using multi-messenger data.The application of our results to GW170817 is discussed.     

稀土Y_(2-x)SiO_5∶Eu_x~(3 )纳米发光材料结构对发光性能影响及发光机理研究

用溶胶凝胶法合成了Y2-xSiO5∶Eux纳米发光材料,使用XRD、FTIR和TEM对其结构进行了表征。讨论了相结构、煅烧温度和Eu3 掺杂浓度对材料发光性能的影响及规律。结果显示煅烧温度在900℃以下,材料主要呈非晶相结构,900℃以上材料主要呈晶态结构;颗粒随煅烧温度升高而增大,在非晶态时颗粒大小在15~45nm,在晶态时颗粒大小为60~80nm。激发光谱和荧光发射光谱受材料晶相结构以及Eu3 掺杂浓度的影响,在晶态结构中Y2-xSiO5∶Eux纳米材料呈现更精细的激发和发射光谱。在激发光谱中,电荷转移态吸收(CST)随煅烧温度升高呈现兰移现象,晶态时CST同非晶态相比明显红移;在发射光谱中,非晶态时5D0→7F2跃迁呈现强的发光峰,随材料制备温度升高而增强,在晶态时该发光峰强度减弱,在长波波段呈现两个新的发光尖峰,并随煅烧温度升高而增强;5D0→7F1发射峰从非晶态转变为晶态后,光谱裂分为三重尖峰;而5D0→7F0跃迁发光光谱受结构和颗粒大小影响较小。同时在60~80nm的Y2-xSiO5∶Eux晶体中,发现材料5D0→7F2和5D0→7F1跃迁发光强度,均受Eu3 掺杂浓度的影响,当掺杂浓度x=0.4时,材料发光强度最大。     

稀土Y2-xSiO5∶Eux3+纳米发光材料结构对发光性能影响及发光机理研究

用溶胶凝胶法合成了Y_2-xSiO₅∶Eu_x纳米发光材料，使用XRD、FTIR和TEM对其结构进行了表征。讨论了相结构、煅烧温度和Eu³⁺掺杂浓度对材料发光性能的影响及规律。结果显示煅烧温度在900 ℃以下，材料主要呈非晶相结构，900 ℃以上材料主要呈晶态结构；颗粒随煅烧温度升高而增大，在非晶态时颗粒大小在15～45 nm，在晶态时颗粒大小为60～80 nm。激发光谱和荧光发射光谱受材料晶相结构以及Eu³⁺掺杂浓度的影响，在晶态结构中Y_2-xSiO₅∶Eu_x纳米材料呈现更精细的激发和发射光谱。在激发光谱中，电荷转移态吸收(CST)随煅烧温度升高呈现兰移现象，晶态时CST同非晶态相比明显红移；在发射光谱中，非晶态时 ⁵D₀→ ⁷F₂跃迁呈现强的发光峰，随材料制备温度升高而增强，在晶态时该发光峰强度减弱，在长波波段呈现两个新的发光尖峰，并随煅烧温度升高而增强； ⁵D₀→ ⁷F₁发射峰从非晶态转变为晶态后，光谱裂分为三重尖峰；而 ⁵D₀→ ⁷F₀跃迁发光光谱受结构和颗粒大小影响较小。同时在60～80 nm的Y_2-xSiO₅∶Eu_x晶体中，发现材料 ⁵D₀→ ⁷F₂和 ⁵D₀→ ⁷F₁跃迁发光强度，均受Eu³⁺掺杂浓度的影响，当掺杂浓度x=0.4时，材料发光强度最大。     

Neutrino emissivity of the nucleon direct URCA process for rotational traditional and hyperonic neutron stars

Based on covariant density functional theory, we study the effects of rotation on the nucleon direct URCA(N-DURCA) process for traditional and hyperonic neutron stars. The calculated results indicate that, for a fixed mass sequence of rotational traditional neutron stars, the neutrino emissivity of the star is nearly invariant with increasing frequency, while it always increases for rotational hyperonic neutron stars. Thus, rotation has different effects on the N-DURCA process for these two kinds of neutron stars.