PbBi2Nb2O9的晶体结构

PbBi₂Nb₂O₉晶体属正交晶系,空间群为D_2h²³-Fmmm。晶胞参数为a=5.4806(7)?,b=5.4791(7)?,c=25.416(3)?,α=β=γ=90.0(0)°,V=763.2(2)?³。单位晶胞内化学式数z=4,D_obs=7.91g/cm³,D_x=8.26g/cm³ 关键词：     

关于Pt偶同位素的h9/2质子对

本文对于Pt偶同位素中的h_9/2质子对的排列现象作了比较系统的计算和讨论.结果表明,如用改善的Nilsson参数κ、μ,给出的h_9/2的排列频率与νi_13/2排列频率的差值Δhω_c=hω_c(πh_9/2)－hω_c(νi_13/2)对于78¹⁸⁴Pt106核具有最小值,约为75keV.这和最近实验上确定的¹⁸⁴Pt核转晕带上出现的大的上弯现象,是由于νi_13/2和πh_9/2两个排列频率非常靠近的结果一致.而运用Nilsson的标准κ、μ则不能给出这一结果.这两个排列的先后次序仍是值得深入研究的问题.对于相邻Pt偶同位素的πh_9/2排列频率的理论预言,期待着实验数据的检验.     

ON πh9/2 ALIGNMENT IN Pt EVEN ISOTOPES

πh_9/2 alignment in Pt even isotopes has calculated and discussed systematically.It is found that Δhω_c≡hω_c(πh_9/2)－hω_c(νi_13/2) approches the minimum,about 75keV.for 78¹⁸⁴Pt106 by using modified Nilsson's parameters κμ.This result is in agreement with the experimental evidence that the big up-bend observed in the yeast band of ¹⁸⁴Pt is caused by the lose alignment of πh_9/2 and νi_13/2.While the standard Nilsson's κμ can not give out such a result.The problem of the orderof πh_9/2 and νi_13/2 alignments needs further investigation.The pretical prediction about the πh_9/2 alignment frequency for neighboring Pt even isotopes should be checked by new experiments.     

πg9/2(⊕)vh11/2 doublet bands in A～100 mass region

Using the model with one particle and one hole coupled with a triaxial rotor, the πg(-1)(9/2)(⊕)vh11/2 doublet bands in the A ～ 100 mass region are studied, and compared with the πh11/2(⊕)vh(-1)(11/2) doublet bands.It is found that the calculated results for the configuration of πg(-1)(9/2)(⊕)vh11/2 are very similar the results for a pure h11/2 proton particle and a neutron quasiparticle with λn =ε5. After including the pair correlation, the model describes the candidate chiral doublet bands in 106Rh successfully, which supports the interpretation of chirality geometry.     

143,145Nd+4f45d6K9/2→(23229.991)o9/2跃迁超精细结构光谱

利用共线快离子束-激光光谱学方法测量了^143,145Nd⁺⁶K_9/2→(23229.991)^o_9/2跃迁的超精细结构光谱,得到了上、下能级的超精细相互作用常数.     

Crystal Structure of β-La2Mo2O9 from First Principles Calculation

Arrangements of O ions in β-La2Mo2O9 are studied by first principles calculation with two different calculation schemes. All final structure configurations consist of MoO4-tetrahedra, MoO5-hexahedra, LaO8 and LaO7 polyhedra. Molybdenum polyhedra are isolated from each other, lanthanum polyhedra are connected together by sharing O ions. The occupancies of three crystallographic distinct O sites O（1）, O（2） and O（3） are 100%, 91.7% and 25%, respectively, consistent with experiments. All configurations are related to each other by one of 12 symmetry operations of P213 space group, suggesting that the structure observed experimentally may be interpreted as a time and spatial average of these local or inherent structures.     

πg9/2⊙νh11/2 doublet bands in A~100 mass region

Using the model with one particle and one hole coupled with a triaxial rotor, the πg^－1_9/2⊙νh_11/2 doublet bands in the A~100 mass region are studied, and compared with the πh_11/2⊙νh^－1_11/2 doublet bands. It is found that the calculated results for the configuration of πg^－1_9/2⊙νh_11/2 are very similar the results for a pure h_11/2 proton particle and a neutron quasiparticle with λ_n=ε₅. After including the pair correlation, the model describes the candidate chiral doublet bands in ¹⁰⁶Rh successfully, which supports the interpretation of chirality geometry.     

πg9/2νh11/2 doublet bands in A～100 mass region

Using the model with one particle and one hole coupled with a triaxial rotor, the πg9/2/1/2νh11/2 doublet bands in the A～100 mass region are studied, and compared with the πg9/2/1/2νh11/2 doublet bands. It is found that the calculated results for the configuration of πg9/2/1/2νh11/2 are very similar the results for a pure h11/2 proton particle and a neutron quasiparticle with λn = ε5. After including the pair correlation, the model describes the candidate chiral doublet bands in 106Rh successfully, which supports the interpretation of chirality geometry.     

连续激光辐照ZnSe/MgF2/K9滤光片的透射特性研究

 分析了连续激光辐照ZnSe/MgF₂/K9滤光片引起透射特性的变化。在室温条件下，用波长0.632 8μm激光作为探测光束，测量了1.06μm连续激光辐照ZnSe/MgF₂/K9滤光片温升引起薄膜折射率的改变，导致探测光束通过干涉滤光片后透过率的热致非线性变化。在光斑直径0.75mm条件下，测量了不同功率激光辐照ZnSe/MgF₂/K9滤光片引起温升随时间的变化。在激光功率30W，辐照时间2.52s条件下，实验观测到ZnSe/MgF₂/K9滤光片薄膜破坏温度约为90℃，辐照时间10s时干涉滤光片形成的薄膜龟裂形貌。     

Properties of the πh 9/2 ⊗ νi 13/2 band in odd-odd 188Au

A new rotational band has been identified and assigned to ¹⁸⁸Au for the first time using the ¹⁷³Yb(¹⁹F,4nγ) reaction at the beam energies of 86 and 90 MeV. This band is proposed to be built on the πh _9/2 ⊗ νi _13/2 configuration by comparing the band properties with known bands in neighboring nuclei. The prolate-to-oblate shape transition through triaxial shape has been proposed to occur around ¹⁸⁸Au for the ηh _9/2 ⊗ νi _13/2 bands in odd-odd Au isotopes on the basis of total Routhian surface (TRS) calculations.

     

1.06μm连续激光辐照TiO_2/SiO_2/K_9薄膜元件温升规律研究

利用1.06μm连续激光在不同强度下辐照TiO2/SiO2/K9薄膜元件,实验中用红外热像仪测量激光辐照在TiO2/SiO2/K9元件表面引起的温升随时间的变化,通过数据处理,获得激光辐照区域最高温度随辐照时间的增加而增加。同时,给出材料温升随材料发射率的变化关系。并用程序模拟不同激光强度下薄膜温度场的分布,通过实验测量数据校正数值模拟计算结果,给出TiO2/SiO2/K9薄膜元件温度随激光辐照强度和辐照时间的变化规律。并且获得在薄膜厚度方向:薄膜表面温度最高,基底与薄膜接触处温度最低;沿径向:激光辐照中心温度最高,边沿温度最低。     

Nuclear matrix elements in the 7/2−–9/2+ beta decay of175Yb

The angular correlation of the \({7 \mathord{\left/ {\vphantom {7 2}} \right. \kern-0em} 2}^ - \xrightarrow[{353keV}]{\beta }{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-0em} 2}^ + \xrightarrow[{114keV}]{\gamma }{7 \mathord{\left/ {\vphantom {7 2}} \right. \kern-0em} 2}^ + \) is measured atE _β =300 keV and found to beA ₂(β,γ)=0.108 ± 0.028. The result is combined with the data on longitudinal polarisation nuclear orientation to obtain the nuclear matrix elements which would give a simultaneous fit to all experimental data. The matrix elements thus obtained have predicted theβ spectrum shape correction factor. The sizes of the matrix elements indicate a cancellation effect in vector matrix elements which explains deviation from ξ-approximation. From the ratio of higher order matrix elements,λ, the deviation from theCVC ratio due to Fujita is found and thus the importance of off-diagonal elements inH _c is noted. The experimental matrix elements are compared with the model-predicted ones.     

1.06 μm连续激光辐照TiO2/SiO2/K9薄膜元件温升规律研究

利用1．06μm连续激光在不同强度下辐照TiO2／SiO2／K9薄膜元件,实验中用红外热像仪测量激光辐照在TiO2／SiO2／K9元件表面引起的温升随时间的变化,通过数据处理,获得激光辐照区域最高温度随辐照时间的增加而增加。同时,给出材料温升随材料发射率的变化关系。并用程序模拟不同激光强度下薄膜温度场的分布,通过实验测量数据校正数值模拟计算结果,给出TiO2／SiO2／K9薄膜元件温度随激光辐照强度和辐照时间的变化规律。并且获得在薄膜厚度方向：薄膜表面温度最高,基底与薄膜接触处温度最低;沿径向：激光辐照中心温度最高,边沿温度最低。     

层状钙钛矿结构铁电薄膜SrBi2Ta2O9的掺杂改性研究

研究了Nb掺杂对层状钙钛矿结构铁电薄膜SrBi₂Ta₂O₉(SBT)的改性，分析了其改性机理.利用光声光谱技术对不同含量Nb掺杂SBT薄膜的可见光吸收进行了分析.结果表明掺杂SBT薄膜在580nm处的吸收带随Nb含量的增加发生红移，这暗示掺杂SBT薄膜的能隙与Nb含量有关.对掺杂SBT薄膜的铁电性质研究表明，薄膜的剩余极化值依赖于薄膜中的Nb含量，这与薄膜存在相界有关. 关键词：     

蓝色荧光粉Sr2B5O9Cl:Eu2+发光特性的研究

采用高温固相法合成了近紫外光激发的蓝色荧光粉Sr₂B₅O₉Cl:Eu²⁺,研究了SrCl₂ ·6H₂O用量和Eu²⁺浓度对其结构和发光性能的影响.随着Eu²⁺浓度的增加,其结构无明显变化,发光强度先增强后减弱,当其浓度为8mol%时,荧光粉的发光强度最大;当用Ca取代Sr时,荧光粉的发射峰从425 nm红移到453 nm. 适当过量 关键词： 氯硼酸盐 蓝色荧光粉 LED     

143,145Nd+ 4f45d6K\-9/2→(23229.991)o\-9/2跃迁超精细结构光谱

利用共线快离子束-激光光谱学方法测量了143,145Nd+ 6K\-9/2→(23229.991)o\-9/2跃迁的超精细结构光谱,得到了上、下能级的超精细相互作用常数.     

NiI［14. 6］2Δ5/2-X 2Δ5/2（9，0）带的超精细结构

在可见光范围内 ,用激光蒸发 /反应、超声射流和激光诱导荧光光谱方法 ,对NiI[14 .6 ]2 △5/ 2 -X2 △5/ 2跃迁的 (9,0 )带进行了高分辨研究 .80MHz分辨的光谱显示超精细结构是由于激发态中未成对电子与碘 (I=5 /2 )核大磁矩相互作用引起的 .在v =9能级上低J谱线的超精细线宽快速下降 ,表明在 [14 .6 ]2 △5/ 2 态中超精细耦合适合Hundaβ 耦合情况 .[14 .6 ]2 △5/ 2 态的精确转动参数和超精细参数已得到 ,而且显示v =9能级被微扰了 .     

Nb XIII离子3d94s2, 3d94s4p, 3d94p2 组态能级结构与跃迁的理论研究

用准相对论Hartree-Fock方法对Nb XIII离子二电子激发组态3d⁹4s², 3d⁹4s4p, 3d⁹4p² 的能级结构做了全面系统的理论计算研究.在对已有研究结果分析的基础上, 运用最小二乘方法对径向积分参数进行了优化计算, 得到了与这些组态有关的电偶极允许跃迁的谱线波长和跃迁概率.计算结果与最新的实验值做了对比分析, 表明本文计算结果是准确的. 研究发现, 波长40.92 nm的谱线, 属于3d⁹4s(¹D)4p²F_7/2–3d⁹ (²D)4s^{2 2}D_5/2 的跃迁谱线, 而不属于3d⁹4s (¹D)4p⁴D_7/2–3d⁹(²D)4s^{2 2}D_5/2 的跃迁谱线, 即上谱项能级为²F_7/2, 而不是⁴D_7/2. 关键词： Nb XIII离子 二电子激发组态 谱线波长 跃迁概率     

SrBi2Ta2O9铁电薄膜微结构及其抗疲劳等铁电特性的研究

在低温Pt/Ti/SiO₂/Si衬底上用脉冲准分子激光沉积技术结合氧气氛下700℃退火获得高质量的SBT薄膜，其择优取向为（008）和（115）．薄膜厚度约为200nm．铁电性能测试显示较饱和的、方形的电滞回线，其剩余极化和矫顽电场分别为10μC/cm²和57kV/cm，在10¹⁰次开关极化后没有显示任何疲劳，在5V直流电压下的漏电流密度约为4×10^-8A/cm²，直流击穿电场约为250kV/cm 关键词：