Eu~(3+)离子掺杂纳米TiO_2的制备及其光催化降解甲基兰溶液的研究

采用溶胶-凝胶法制备了系列不同原子摩尔比的Eu3+离子掺杂纳米TiO2光催化剂,通过XRD,SEM和UV-V is等测试手段对纳米TiO2晶型、颗粒度大小、形貌以及光学性能进行了表征;并以甲基兰溶液为目标物,对所制备样品的光催化活性进行了研究。结果表明,稀土Eu3+离子的掺杂能有效抑制纳米TiO2的晶型的转变进而减小晶粒尺寸、提高分散度;稀土Eu3+离子的掺杂使TiO2光催化剂紫外-可见吸收有一定的蓝移,并在可见区有一定的吸收峰;稀土Eu3+离子的掺杂有效提高了TiO2光催化剂的活性,并在本实验条件下,当掺杂原子摩尔比为1%、退火温度500℃时,对甲基兰溶液的光催化活性最强。     

牛血清白蛋白与纳米银的相互作用及半胱氨酸的检测

表面无保护剂的小粒径纳米银与牛血清白蛋白（BSA）的相互作用可引起BSA特征荧光的猝灭。而若先向体系中加入半胱氨酸（Cys）,其巯基与A g的强相互作用可降低体系中的纳米银与BSA的相互作用,使BSA荧光猝灭程度降低。体系在350nm处荧光强度的变化与Cys的浓度呈线性关系,线性范围为3.3×10-8—3.3×10-4m ol/L,相关系数为0.9982。基于这种光谱的变化,可用来测定Cys。     

The atom-photon entanglement of a two-level system embedded in double-band photonic band edge

The entanglement of a two-level atom with its spontaneously emitted photon embedded in double-band anisotropic photonic crystal has been investigated via the method of the quantum entropy. Different from the case in an isotropic crystal or in vacuum, the entanglement has symmetrical properties and much slower entanglement rate near the two band edges. Moreover, as a result of the atom-photon bound states by the virtue of the localization around the emitting atom, the degree of the entanglement gradually increases, achieves the maximum and then sharply reduces to zero on the boundary of forbidden band gap as the atomic frequency moves from the center of the band gap to either of the band edges.     

(Fe0.03Ni0.97)8(Si0.79P0.21)3的等温状态方程研究

 采用固态高温烧结反应方法,成功合成出了陨硅镍铁石样品(Fe_0.03Ni_0.97)₈(Si_0.79P_0.21)₃。X射线衍射结果表明,合成样品的结构为R3'c,对应的晶胞参数为a=b=0.663 8(1) nm,c=3.789 2(2) nm,V=1.446 15(6) nm³。在室温下,对样品进行原位高压X射线衍射研究,实验最高压力达到21.3 GPa,随着压力的升高,晶胞体积逐渐减小,但并没有观察到结构相变。利用Birch-Murnaghan状态方程对体积与压力的关系进行拟合,获得常温常压下的体积V₀=1.441 4(24) nm³,体积模量K₀=220(7) GPa。晶轴与压力的关系利用Murnaghan状态方程拟合,获得a轴和c轴的模量分别为K_a=257(9)和K_c=165(4),c轴较a轴容易压缩。     

低反轰热阴极微波电子枪初步实验

 简述了紧凑型自由电子激光太赫兹源研制的系统设计方案,介绍了具有两路微波馈入的热阴极微波电子枪的研制与测试情况,利用束流传感器测试了束流强度,并利用CCD相机测试了束斑大小,给出了微波电子枪通过初步热测实验得到的结果。测得微波电子枪出口处束流强度超过500 mA,束斑约3 mm,采用双屏法测量束流发射度,得到归一化发射度约为13.5 π·mm·mrad,测试指标与理论设计值吻合较好。     

某光电雷达稳定平台关键部件转板的动态特性分析

 转板是光电雷达稳定平台的关键元件之一。为了更好地设计和分析某光电雷达稳定平台的转板,运用Pro E软件对其进行三维实体建模,合理简化后,进入Ansys软件界面建立有限元模型。应用有限元理论和Ansys软件对其进行动态特性分析,得到了转板前八阶模态的固有频率和振型,以及要求范围内的谐响应。对比了不同方法划分网格的网格质量,采取不同材料得到了不同模态。分析结果表明：设计的转板在关心的频段0~50 Hz,2 000 Hz~8 000 Hz内不发生共振,符合设计要求。     

High pressure X-ray diffraction study of SrMnO3 perovskite

Using a diamond anvil cell device and synchrotron radiation, the in-situ high-pressure structure of SrMnO3 has been investigated. At pressure up to 28.6 GPa, no pressure-induced phase transition is observed. The lattice parameters as a function of pressure is reported, and the relationship of the axial compression coefficients is β<,a>> β<,c>. The isothermal bulk modulus K<,298>=266(4) GPa is also obtained by fitting the pressure- volume data using the Murnaghan equation of state.     

Theoretical study of photon emission from single quantum dot emitter coupled to surface plasmons

Motivated by the recent pioneering advances on nanoscale plasmonics and also nanophotonics technology based on the surface plasmons (SPs), in this work, we give a master equation model in the Lindblad form and investigate the quantum optical properties of single quantum dot (QD) emitter coupled to the SPs of a metallic nanowire. Our main results demonstrate the QD luminescence results of photon emission show three distinctive regimes depending on the distance between QD and metallic nanowire, which elucidates a crossover passing from being metallic dissipative for much smaller emitter-nanowire distances to surface plasmon (SP) emission for larger separations at the vicinity of plasmonic metallic nanowire. Besides, our results also indicate that, for both the resonant case and the detuning case, through measuring QD emitter luminescence spectra and second-order correlation functions, the information about the QD emitter coupling to the SPs of the dissipative metallic nanowire can be extracted. This theoretical study will serve as an introduction to understanding the nanoplasmonic imaging spectroscopy and pave a new way to realize the quantum information devices.     

Accumulation effect of SiO_2 protective layer on multi-shot laser-induced damage in high-reflectivity HfO_2/SiO_2 coatings

The accumulation effects in high-reflectivity(HR) HfO2/SiO2 coatings under laser irradiation are investigated.The HR HfO2/SiO2 coatings are prepared by electron beam evaporation at 1 064 nm.The laser-induced damage threshold(LIDT) are measured at 1 064 nm and at a pulse duration of 12 ns,in 1-on-1 and S-on-1 modes.Multi-shot LIDT is lower than single-shot LIDT.The laser-induced and native defects play an important role in the multi-shot mode.A correlative theory model based on critical conduction band electron density is constructed to elucidate the experimental phenomena.     

MgO-decorated carbon nanotubes for CO2 adsorption: first principles calculations

The global greenhouse effect makes it urgent to deal with the increasing greenhouse gases.In this paper the performance of MgO-decorated carbon nanotubes for CO 2 adsorption is investigated through first principles calculations.The results show that the MgO-decorated carbon nanotubes can adsorb CO 2 well and are relatively insensitive to O 2 and N 2 at the same time.The binding energy arrives at 1.18 eV for the single-MgO-decorated carbon nanotube adsorbing one CO 2 molecule,while the corresponding values for O 2 and N 2 are 0.55 eV and 0.06 eV,respectively.In addition,multi-molecule adsorption is also proved to be very satisfactory.These results indicate that MgO-decorated carbon nanotubes have great potential applications in industrial and environmental processes.