有机电致发光材料8-羟基喹啉铝的结构表征

叙述了制备高纯度有机电致发光材料8－羟基喹啉铝（Alq3)的方法；通过X射线衍射谱、核磁共振谱、红外吸收光谱、质谱、X射线光电子发射谱及荧光光谱测试分析，对Alq3的结构和特性进行了表征。标定了Alq3中喹啉环的存在；分析了Alq3中各个H原子的归属、Alq3分子内部金属离子和配位体之间的相互作用以及该螯合物的分子构型。进一步证实Alq3分子中Al-O键为共价键而非离子键。通过X射线衍射谱分析了样品的化学成分；由X射线光电子发射谱分析了Alq3分子中的电子状态和晶体特性。得到了Alq3的荷质比为459.1以及由于金属Al本身的特性，使得在Alq3中Alq2^ 继续裂解为Alq^ 的几率很小。证实了Alq3的荧光发射光谱位于510nm处（绿光范围），光激发位于喹啉环上而不是金属铝离子。与镓、铟螯合物相比，Alq3中铝离子成键共价性弱，极化力较强。     

近红外区的光泵钠分子激光振荡

本文报道了以准分子激光泵浦的染料激光激发钠分子,产生由钠分子A~1 sum from u to +态到X~1 sum from g to +态的众多激光输出谱线.当加以谐振腔后,这些谱线的强度可增加一个数量级.     

凝聚相有机分子的激发能传递研究(Ⅱ)——激光染料二甲基-POPOP和DCM分子间的激发能传递

利用荧光发射及其衰变动力学测量,研究了激光染料分子二甲基-POPOP和DCM在溶液中的分子间能量传递。所得结果证实:激发态二甲基-POPOP分子荧光被猝灭的程度,随所加入DCM浓度的增大而增大。尽管DCM的荧光寿命随二甲基-POPOP的猝灭而增加。然而,DCM的加入并不改变二甲基-POPOP的荧光寿命。在固定DCM浓度,而增加二甲基-POPOP浓度时,相似的结果同样被观测到。这些结果表明:激发态二甲基-POPOP分子通过辐射传能机理向基态DCM传递激发能,其结果将入射光的波长从紫外直接转换到波长大于600nm的光谱区。在本文中也简要讨论了进一步改善这一传能过程效率的措施。     

光泵香豆素染料介质光解机理的研究

本文报导C_(311)/乙醇溶液光解机理的研究.在光解前后,对香豆素C_(311)激光染料介质进行了吸收、荧光、红外和核磁共振谱的测定,实验结果表明在Nd:YAG三次谐波355nm和脉冲氙灯泵浦条件下,溶剂光解产物主要为乙酸.据此提出下列激光诱导光化学反应机理;在UV激光或脉冲氙灯泵浦条件下,溶剂中的氧由于高位三重态T_2染料分子的能量转移而被激发,并氧化香豆素分子生成隐色基.     

凝聚相有机分子的激发能传递研究(Ⅱ)——激光染料二甲基-POPOP和DCM分子间的激发能传递

利用荧光发射及其衰变动力学测量,研究了激光染料分子二甲基-POPOP和DCM在溶液中的分子间能量传递。所得结果证实:激发态二甲基—POPOP分子荧光被猝灭的程度,随所加入DCM浓度的增大而增大。尽管DCM的荧光寿命随二甲基—POPOP的猝灭而增加。然而,DCM的加入并不改变二甲基—POPOP的荧光寿命。在固定DCM浓度,而增加二甲基—POPOP浓度时,相似的结果同样被观测到。这些结果表明:激发态二甲基—POPOP分子通过辐射传能机理向基态DCM传递激发能,其结果将入射光的波长从紫外直接转换到波长大于600nm的光谱区。在本文中也简要讨论了进一步改善这一传能过程效率的措施。     

激光染料的反斯托克斯荧光制冷计算

从理论上研究了具有分子振动能级结构的激光染料分子的反斯托克斯荧光制冷总是根据吸收光谱和荧光发射谱,对Ｒｈｏｄａｍｉｎｅ１０１溶液的反斯托克斯我制冷有力进行了数值计算,得到了用该种材料实现激光制冷的条件与制冷效率相关的曲线。     

XeF,KrF准分子激光泵浦染料激光器

在各种波长的可调谐激光器中,染料激光器具有设备简单、制作方便、价格低廉、调谐范围宽等一系列优点,受到研究和应用方面的普遍重视.激光泵浦是获得染料激射作用的重要而有效途径.迄今为止,用来泵浦染料的激光器主要有以下几种:YAG的高次谐波[1],红宝石激光器及其二次谐波[2],Ar离子激光器[3],N2分子激光器[4]及准分子激光器[5,6]等. N2分子激光器因其结构简单.已成为许多染料的泵浦源,用N2激光泵浦的染料激光器已做到从355nm到655um的调谐输出和100kw的峰值功率.然而欲进一步提高输出功率和扩大调谐到更短波长区,却受到N2激光器本身可…     

掺镱钼酸锶激光晶体的光谱研究

通过晶体的吸收光谱和荧光光谱研究了Yb3+:SrMoO4激光晶体的光谱性能.由吸收光谱得到晶体在976 nm有最强吸收,该处的吸收截面为1.71×10-20cm2,吸收半峰宽为71 nm.由荧光光谱得到晶体的发射峰在1 021 nm,发射谱带半峰宽为44 nm.由倒易法计算了晶体的发射截面,计算得出晶体在1 021 nm处的发射截面为1.24×10-20cm2.通过拟合荧光寿命衰减曲线得到Yb3+:SrMoO4晶体的荧光寿命为878μs.由光谱数据计算了Yb3+:SrMoO4晶体的激光参数,计算得到饱和泵浦功率密度为4.35 kW/cm2,在激光输出波长处净透过所需要激发粒子的最小分数为10.08%,最小泵浦功率密度为O.44 kW/cm2.Yb3+:SrMoO4晶体具有较大的吸收和发射半峰宽,较长的荧光寿命和较低的激光阈值,可成为一种潜在的LD泵浦激光材料,可能应用于飞秒激光及可调谐激光领域.     

HoP5O14非晶的上转换荧光现象

本文首次报导使用脉冲DCM染料激光激发,在室温下观察到的HoP5O14非晶的上转换荧光现象,发现蓝移的发射可归结为激发离子对之间的相互作用,本文还对其上转换通道进行了分析。     

铜离子空心阴极紫外激光器

G.J.Collins[1]等人于 1976年首先研制成功铜离子空心阴极紫外(2500A区)激光器.它比起惰性气体紫外激光器具有较高的激发效率,而工作效率约大一个数量级,近来已获得较大的输出功率[2],并已在泵浦染料激光等方面投入实际的应用.它在激光化学、生物、医学以及激发荧光的科学研究方面有着重要的应用价值;在成分分析、精密测量、激光全息、喇曼光谱等有着广泛的用途.我们在研制成功氦-铜空心阴极7808A激光器[3]的基础上,最近又研制成功了氖-铜空心阴极紫外激光器. 铜离子能级简图见图1.从图中可见,这些紫外谱线的上能级都很接近Ne离子的电离…     

内爆腔X光发射机制研究

介绍了首次利用三台亚千X光能谱仪和一台针孔相机研究腔靶内爆区X光发射机制,实验结果表明内爆区X光发射主要是壁X光面发射。     

热核衰变中轻粒子的发射时间

报道了25MeV/u ⁴⁰Ar+¹⁹⁷Au反应中裂片符合下的粒子—粒子关联函数及其发射时间.实验测得粒子的平均发射时间为200—300fm/c,表明轻粒子的裂前发射占主导.在平面发射和出平面发射的粒子发射时间相差很少,发射时间是随着粒子能量的改变而发生显著变化,从中速粒子的约300fm/c下降至类弹粒子的约30—100fm/c.     

Amplified Emissions Spectroscopy for Sensing Applications

Amplified emission spectroscopy is promising for applications of qualitative and quantitative sensing of elements and their states. This technique has the characteristics of a narrow spectral line, high spectral resolution, and high signal‐to‐noise ratio. Recently, this technology has advanced tremendously with progress in excitation methods, that is, resonance multiphoton absorption and filamentation with ultrafast lasers. The mechanism, conditions, excitation, signal processing, and applications of amplified emission spectroscopy are reviewed herein. In particular, the different formation patterns of the amplified emission spectra produced by an ultrafast laser are analyzed in detail. In addition, a brief introduction is given to the existing applications of amplified emission. Finally, both a conclusion and a perspective of the future for amplified emission are presented.     

The effect of electric field strength on electroplex emission at the interface of NPB/PBD organic light-emitting diodes

Organic light-emitting diode (OLED) based on two kinds of blue emission materials N,N′-bis(1-naphthyl)-N,N′-diphenyl-l,l′-diphenyl-4,4′-diamine (NPB) and 2-(4-biphenylyl)-5(4-tert-butyl-phenyl)-1,3,4-oxadiazole (PBD) was fabricated. There is only one emission peak in photoluminescence (PL) spectrum which originates from NPB exciton emission. And the electroluminescence (EL) emission peaks have an apparent red-shift with the increase of driving voltage. The red-shift emission from exciplex emission could be ruled out. Thus, by the method of Gaussian fitting it should be ascribed to the overlap of exciton emission and electroplex emission which occurs at the interface between NPB and PBD. The formation of the electroplex emission under high electric field is analyzed.     

Search for γ-Emission from Isomeric Nuclei Induced by MeV Electron Beams

In this paper we study the nuclear transitions induced by incident electrons having an energy of several MeV's. We measured the cross sections for the excitation of isomeric nuclear states by 7.7 MeV electrons. The cross sections were 1.2 μb for ^111m Cd, 5.5 μb for ^113m In and 7.0 μb for ^115m In. The peak activation rates were 1.8×10⁻¹² s⁻¹ for ^111m Cd, 8.1×10⁻¹² s⁻¹ for ^113m In and 1.0×10⁻¹¹ s⁻¹ for ^115m In, for a peak power of the electron beam of 1.8×10⁶ W cm⁻². Then we describe for the first time the results of a series of experiments in which samples containing the isomeric nuclei ^166m Ho and ^186m Re have been irradiated with MeV electron beams. An upper limit of 17 mb has been determined for the cross section of electron-induced γ-emission from ^166m Ho and an upper limit of 2.2 mb has been determined for the cross section of electron-induced γ-emission from ^186m Re. This revised version was published online in July 2006 with corrections to the Cover Date.     

三维热场致发射模型的数值模拟与研究

研究了场致发射与热电子发射的基本理论, 得出热场致发射的适用公式, 探讨了其粒子的初始分布和初始动量, 并在FDTD-PIC原理的基础上编写了软件, 分别实现了场致发射模型, 热电子发射模型和热场致发射模型, 通过分别对一个长楔形阴极器件的数值模拟, 从发射电流特性, 电子初始能量分布等方面验证了其正确性.     

The Absorption Spectrum of UF6, from 2000 to 4200 Å

The absorption spectrum of UF₆ between 3400 and 4200 Å, is well-documented,^(1–3) but the region below 3400 Å has not been studied in any detail. We present here a spectrum of UF₆ between 2000 and 4200 Å that shows significant structure below 3400 Å. The absorption in this region must be observed at very low pressures and relatively short path lengths.     

The “Average” Work Function and Emission Area in the Fowler-Nordheim Equation

Derivation of the elementary Fowler-Nordheim equation is based on several strong physical assumptions (e.g. smooth flat surface and uniform work function across emitting surface, constant emission area and a uniform distribution of the applied field over it). A real emitter, however, definitely does not fulfill these assumptions. In spite of it the total emission current follows the FN equation and is frequently used for an estimation of the "average" work-function. The physical basis of this procedure and of the terms "average" work function and "emission area" are analyzed from the experimentalist's point of view. Thus some of the older - more or less intuitive - conclusions are substantiated.     

中能核反应中碰撞参数的确定

介绍了中高能核反应过程中与碰撞参数相关的可观测量.确定碰撞参数的各种方法 ,以及这些方法的适用范围和可靠性.这些方法包括约化线性动量转移、带电离子多重性、横向动量的方向性、横向动能和纵向动能的比 Erat、 Zbound和椭圆流参量. Observables that related to the impact parameters in intermediate and relativistic energy heavy ion reactions were introduced. These observables that related to the impact parameter include linear momentum transfer, multiplicities of charged particles, the ratio of transverse kinetic energy and longitudinal kinetic energy E rat , the transverse momentum directivity, Z bound , elliptic flow etc. Impact parameter determination for intermediate and relativistic energy heavy...     

Exciplex or electroplex emissions from the interface between aromatic diamine and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline?

Organic light-emitting diodes (OLEDs) have been fabricated which consist of N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine) (TPD), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and tris(8-hydroxyquinoline) aluminum (Alq₃). Four emission peaks located at about 401 nm, 425 nm, 452 nm and 480 nm have been obtained in the electroluminescence (EL) spectra of these devices. The former two emissions originate from the exciton emission of TPD molecular. The last two emissions could be attributed to local (LOC) exiplex emission and charge transfer (CT) exiplex emission at the interface between TPD and BCP layers, respectively.