纳米Gd2O3：（Ce^3＋,Eu^3＋）在UV和VUV选择激发下的荧光光谱

本报道了纳米Gd2O3:(Ce^3 ,Eu^3 ）在紫外以及真空紫外（UV－VUV）选择激发下的荧光光谱。这些光谱实验表明，Gd2O3:(Ce^3 ,Eu^3 ）中Ce^3-占据两种不同格位。除了Gd2O3基质与Ce^3 ,Eu^3 离子之间的能量传递外，还存在着较弱的Ce^3 与Eu^3 间的能量传递。     

纳米Gd2O3：（Ce^3＋,Eu^3＋）中稀土离子间的级联能量传递

本报道了纳米Gd2O3:(Ce^3 ,Eu^3 ）的紫外以及真空紫外（UV－VU）的激发光谱及其选择激发下的荧光光谱。这些光谱实验表明，除了Gd2O3,E^3 离子之间的能量传递外，还存在着Gd^3 与Ce^3 、Eu^3 间的能量传递，即存在Gd^3＋→Ce^3 →Eu^3 三种稀土离子间的级联传递。     

Gd2 SiO5:Eu3+ 的VUV-UV光谱特性

本文介绍了利用同步辐射光源对Gd2SiO5:Eu^3 的VUV－UV光谱特性进行的研究。重点讨论了在低温（10K）及室温下Gd2SiO5:Eu^3 中存在的各种能量传递过程，包括基质向Eu^3 ,Gd^3向Eu^3 的传递以及两种不同格位Eu^3 离子之间的能量传递。另一方面从探索新型量子剪裁材料的角度对比了186nm和276nm激发下的发射谱，指出Gd2SiO5:Eu^3 中可以发生有效的量子剪裁。     

新型稀土硼酸盐和氟化物的结构与VUV荧光性质

本描述了GdB5O9、NaGdF4的合成与结构以及NaGdF4在高温下的相转变。粉末衍射数据表明GdB5O9属于四方晶系，其空间群为：I4 l／acd，晶胞参数为：α=8．23813。c=33．6377。六方和立方NaGdF4分别与NaEuF4和CaF2同构。本还考察了GdB5O9：Eu、六方NaGdF4：Eu、立方NaGdF4：Eu样品的真空紫外(VUV)荧光性质．上述三种样品中Gd3 的4f-5d跃迁及基质的吸收位于真空紫外波段。     

空气条件下合成的CaBPO5:Eu、SrB4O7:Eu和Ba3(PO4)2:Eu的XANES和发光性质

测定了采用高温固相反应在空气条件下合成的发光体CaBPO5：Eu、SrB4O7：Eu和Ba3(PO4）2：Eu的Eu-L3边的X射线吸收近边结构(XANES)谱和发光光谱。从发光体的Eu—L3边XANES可见，Eu^3 -L3边能量比Eu^2 -L3边能量高7—8eV；3个发光体的激发光谱和发射光谱均可看到Eu^2 的4f-5d跃迁和Eu^3 的4f-4f跃迁。发光体的Eu—L3边的XANES和发光光谱说明空气条件下合成的发光体中Eu^3 可部分还原为Eu^2 。     

PVA和PEG对电子束辐照制备的Fe3O4纳米粒子的影响

常温常压下不加入任何催化剂，用两种不同的活性剂聚乙烯醇（Polyvinyl alcohol，PVA）和聚乙二醇（Polyethylene glycol，PEG），在水溶液中通过电子束辐照可以成功地制备纳米Fe3O4粒子。通过紫外可见光分光光度计（Ultraviolet-visible spectrophotometer，UV）、X射线衍射（x-ray diffraction）、透射电子显微镜（Transmission electron microscopy，TEM）对辐照后的样品的光学特性、结构、形貌、大小进行表征。发现不同的活性剂对纳米粒子的尺寸会产生影响。     

同步辐射自由电子激光光学速调管研制

报告了一同步辐射自由电子激光光学速调管的研制情况。此装置已应用在中国科技大学国家同步辐射实验室的储存环上进行同步辐射自由电子激光相干辐射的研究。装置具有光学速调管以及均匀波荡器两种工作模式,已用于短波长相干谐波辐射自由电子激光的研究,以期得到紫外(UV)、真空紫外(VUV)和软X射线波段的相干光源,也用于产生高亮度     

LiD与H2O反应机理及动力学

在6-311G（d）水平下,采用微扰理论的MP2方法,研究了LiD与H2O的反应。结果表明,反应存在两个通道：LiD+H2O→LiOH+HD（R1）;LiD+H2O→LiOD+H2（R2）。298K下,两通道的势垒高度分别为9.31和195.08kJ/mol,反应速率常数分别为1.88×1010和3.74×10－26（mol•dm－3）－1•s－1。     

C60与甲苯的激光诱导反应

在激光辐照下,C60与甲苯反应形成了一系列的富勒烯衍生物,对其中的可溶产物进行的高效液相色谱－质谱－紫外光谱（HPLC－MS－UV）分析研究表明,反应产物中包括C60（C7H7),C60H,C60(C7H7)nOm等,它们的形成可能与甲苯在激光作用下形成的自由基有关,多级质谱（MS／MS）分析表明,这些衍生物是自由基链结在笼状C60外围的结果。     

硅上异质外延氧化铝的X射线测试分析

高剂量X射线粉末衍射测试说明升高温度有利于γ－Al2O3/Si外延生长，单晶衍射法证明应用低压CVD和高真空外延技术在我们的实验室生长出γ－Al2O3/Siuj单晶薄膜。它们的结晶关系是（100）γ－Al2O3/／Si，[010]γ－Al2O3//[010]Si。     

Generation of reactive atomic species of positive pulsed corona discharges in wetted atmospheric flows of nitrogen and oxygen

The emission spectra of excited radicals(OH(A~2E),O(3p~3 P),H_α(3P)) and emissive species(N_2~+(B~2∑_u~+),N_2(C_3Π_u)) produced by positive pulsed high-voltage needle-plane corona discharges in atmospheric N_2 and O_2 flows wetted with 10%H_2O at 80 ℃ are used to investigate the relative concentrations of the produced radicals.The results indicate that the tendencies of the concentrations of radicals with discharge conditions are similar to each other due to their similar excitation processes by electron collision.The influence of oxygen flow mixed with the nitrogen flow on the emission intensities of O(3p~5P → 3s~5S_2~.),H_α(3P → 2S),N_2_+(B~2∑_u~+ → X~2∑_g+0-0),and N_2(C~3Π_u → B~3Π_g 1-0) is presented.When the flow rate of oxygen addition is varied from 0-30 ml min~(-1),the emission intensities of O(3p~5P → 3s~5S_2~0.),H_α(3P → 2s),and N_2~+(B~2∑_u~+ →X~2∑_g 0-0) increase and reach a maximum.Then,if the oxygen flow rate increases further,the emission intensities tend to decrease.However,the intensity of N_2(C~3Π_u → B~3Π_g1-0) decreases monotonously with the increasing oxygen flow,which indicates that the electron density decreases with the increasing oxygen flow.By the tendencies of the relative intensities to N_2(C~3Π_u → B~3Π_g 1-0),the concentrations of the total produced O,H,and N_2~+ are shown to increase with the oxygen flow.Based on the reactions for the production of H and O without and with the addition of O_2,the analytic solutions for H and O production are derived in accordance with the experimental results.     

掺入Dy和Mn的MgSO4磷光体的热释光发光光谱

用光学多道分析器和微机控制线性升温法研究了MgSO4:Dy和MgSO4:Dy,Mn热释光材料的发光光谱,测定不同温度和波长的发光光谱,得到了热释光三维光谱图。观察到MgSO4掺入稀土元素Dy的两个发光谱带为480nm和580nm,每个光谱带有多个发光峰。与掺入Dy的CaSO4的三维发光谱相比较,掺入稀土元素Dy的热释光材料的发光谱带的波长主要取决于掺入Dy^3 的能级间的跃迁。MgSO4同时掺入Dy和Mn后,480nm发光谱带受到很大的抑制,所有发光峰的发光效应显著减小;波长为580nm谱带的多个发光峰中,温度低于300℃的发光峰的发光效率显著减小,在380℃附近的发光峰的发光强度最大。这说明掺入Mn杂质后,不同深度的陷阱的相对分布发生了变化。     

Photon emission mechanisms of different phosphors

A comparison is made between the different mechanisms involved in the electron and photon excitation processes of four different phosphors. The green luminescence peak of SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor is normally asymmetrical and tails towards the longer wavelengths. The observed peak in the longer wavelength region is associated with preferential alignment of one of the Eu²⁺ d-orbitals. Four Gaussian peaks fitted to the cathodoluminescent (CL) and photoluminescent (PL) spectra of broad band emission spectra of X₁-Y₂SiO₅:Ce phosphor may be attributed to the two different sites (A1 and A2) of the Ce³⁺ ion in the host matrix and the difference in orientation of the neighbour ions in the complex crystal structure. Co-activation of Ce³⁺ with Eu³⁺ quenches the red emission from Eu³⁺ and considerably increases the blue emission from Ce³⁺ in a SiO₂ matrix. In nanoparticulate PbS the emission data show a blue shift from the normal emission at ∼3200 nm in PbS bulk to ∼560-700 nm. The blue shifting of the emission wavelengths from 3200 to ∼560-700 nm is attributed to quantum confinement of charge carriers in the restricted volume of nanoparticles.     

Material dependence of total electron emission yields following slow highly charged ion impact

The total electron emission yields following the interaction of “Slow (2 keV/a.u.) Highly Charged Ions” (SHCI) (O³⁺⁷⁺, Xe¹²⁺⁵²⁺, Au⁵⁴⁺⁶⁹⁺) with different target surfaces (highly-oriented pyrolytic graphite (HOPG), Au and SiO2) have been measured. The emission yields increase with charge state, and is found to be highest for carbon, the HOPG target, and lowest for the SiO₂ target. An empirical formula for the electron emission is including recent results from investigations of plasmon excitation following SHCI impact are used to interpret the results.     

HPuO分子激发态的外场效应

采用密度泛函(DFT)方法B3LYP/Gen,在Pu为相对论有效原子实势(RECP)基组水平上,优化计算得到了分子轴方向不同电偶极场（－0.005～0.005a.u.）作用下的HPuO的基态几何结构、偶极矩和分子总能量。在优化构型下,用同样的基组,采用含时密度泛函(TDDFT)方法(TD-B3LYP),研究了同样外电场条件下对HPuO的激发能的影响。计算结果表明,在外场作用下,对HPuO的前5个激发态电子跃迁光谱属于红外 远红外光谱,波长为1046.0～3038.7nm,这是钚原子的奇异特征。激发能与外电场的关系近似满足Grozema等提出的关系。     

Electrical characters and optical emission spectra of VBD coupled SBD excited by sine AC voltage in atmospheric air

In this paper,volume coupled surface barrier discharge(V-SBD) with three structures possessing different volumes is excited by sine AC power in atmospheric air.Discharge images,waveforms of applied voltage and discharge current,and optical emission spectra simulating rotational and vibrational temperatures are recorded and analyzed.The effects of applied voltage on emission intensities of N_2(C~3Π_u→ B~3Π_g) and N_2~+(B~2∑_u~+ → X~2E_g~+),and rotational and vibrational temperatures are investigated.The results show that as applied voltage rises,emission intensities and rotational temperatures increase while vibrational temperatures decrease.In addition it is found that,as applied voltage varies,the rotational temperature of surface discharge changes faster than that of volume discharge.     

Luminescent monitoring of metal dititanium triphosphates as promising materials for radioactive waste confinement

The potential use of luminescent probes for control over the structural state of MTi₂(PO₄)₃ double metal phosphates as host materials for radioactive waste confinement is examined. Luminescence spectra of pure and metal (Al, In, V) and rare-earth (Pr, Sm, Dy) doped MTi₂(PO₄)₃ (M = Li, Na, K) phosphate compounds (in crystalline and related amorphous forms) under X-ray, VUV (synchrotron radiation), UV and visible light excitations are analyzed. Electronic structure and absorption spectra of NaTi₂(PO₄)₃ crystals are calculated by the full-potential LAPW method. The origin of the self and impurity emission bands of MTi₂(PO₄)₃ materials is defined. It was shown that nitrogen laser with 337.1 nm generation wavelength is the most effective excitation source for remote monitoring of incorporation of various types of waste elements into MTi₂(PO₄)₃ hosts and for control over states of these hosts during storage of radioactive waste.