邻氨基苯甲酸2,2′-联吡啶铕镧混合稀土配合物的红外及荧光研究

用邻氨基苯甲酸和２,２′－联吡啶与氯化铕和氯化镧在溶液中反应,合成了混合混合稀土配合物,测定了配合物的红外光谱及荧光光谱,结果表明,稀土离子均与配体形成配合物,在３４３ｎｍ紫外光激发下,在一定范围内,用不发光的Ｌａ＾３＋离子取代邻氨基苯甲酸－２,２′联吡啶铕配合物中的Ｅｕ＾３＋离子,可以提高Ｅｕ＾３＋离子的特征发光强度,而对发射峰位影响不大,本文对发光机理进行了初探。     

八面体结构纳米CeO2:Er^3+;的合成及发光性质

采用水热合成法制备了八面体结构纳米CeO2∶Er^3+,并研究了稀土Er^3+离子掺杂对CeO2纳米晶的结构以及发光特性的影响。所合成的CeO2纳米晶具有八面体结构,结晶完好,粒度均匀。XRD和拉曼光谱测试结果表明所制备的CeO2纳米晶为面心立方萤石结构,稀土Er^3+离子的掺杂在基质晶格中产生了氧空位缺陷,并产生了晶格畸变。在980 nm激光激发下产生了稀土Er^3+离子绿色(2H11/2,4S3/2→4I15/2)、红色(4F9/2→4I15/2)和近红外(4I11/2,4I13/2→4I15/2)发光。随着稀土Er^3+离子掺杂浓度的变化,样品的发光光谱在可见光和近红外光范围产生了不同的猝灭浓度,这是由于掺杂浓度变化对Er^3+-Er^3+之间的交叉驰豫过程产生了影响,Er^3+的能级布居变化引起了发光特性的改变。     

二苯甲酰甲烷2，2′—联吡啶混合稀土配合物中钆、钇对铕发光的影响

在乙醇溶液中合成了以二苯甲酰基甲烷（DBM）和2，2′联吡啶（Dipy)为配体，三价铕、等摩尔三价铕－钆及等摩尔三价铕－钇混合稀土为中心体的配合物。测定了配合物的组成，研究了其红外光谱和荧光光谱。结果表明：配合物的最佳激发波长为425nm；在425nm波长光激发下，配合物发出较强的荧光；不发光的Gd^3 和Y^3 离子对Eu^3 离子的发光有一定增强作用，其中钇使铕的荧光发射增强大于钆；这两个不发光稀土离子对铕的发射峰位影响不大。     

Eu(p-PBA)_3phen1/2H_2O的高分辨光谱和Raman光谱Eu(p-PBA)3phen1/2H2O的高分辨光谱和Raman光谱*张颖唐波金林培(北京师范大学化学系,北京100875)吕少哲黄世华(中国科学院激发

配合物Ｅｕ（ｐ－ＰＢＡ）３ｐｈｅｎ１／２Ｈ２Ｏ（ｐ－ＰＢＡ：对苯基苯甲酸酸根离子；ｐｈｅｎ：邻菲咯啉）在紫外光激发下，能发出很强的红色荧光．以Ｅｕ（Ⅲ）离子为光谱探针，７７Ｋ下测得其高分辨激发和发射光谱，选择激发配合物的５Ｄ０能级，得到两组不同的发光光谱，表明配合物中Ｅｕ（Ⅲ）离子有两种不同的化学环境．配合物的喇曼光谱中，羧基阴离子的反对称伸缩振动和对称伸缩振动谱带是明显分裂和带肩峰的宽带，说明配合物中羧基同时存在多种配位方式     

稀土-铬蓝黑R配合物体系的近红外发光研究

研究了金属指示剂铬蓝黑R对Yb3 的近红外发光的敏化作用。结果表明 ,在中性乙醇溶液中 ,铬蓝黑R和Yb3 离子可形成配比为 2∶1的配合物。配合物的形成可猝灭配体铬蓝黑R的荧光 ,同时使Yb3 离子的荧光得到显著增强。表现出配体向Yb3 离子传能的机理。在一定条件下 ,配合物体系中Yb3 离子的发光强度与Yb3 离子的浓度成正比 ,同时其他低浓度稀土离子的存在不会影响Yb3 离子的发光 ,显示出近红外发光技术在单一稀土分析中良好的应用前景。     

掺杂稀土对铕、铽苯二甲酸-冠醚配合物发光的影响

合成了稀土Eu3 ,Tb3 冠醚、对苯二甲酸高氯酸盐两个系列18种固态配合物。结果表明,配合物的组成为:Eu2LL′2(ClO4)4.4H2O、EuReLL′2(ClO4)4.nH2O、Tb2LL′2(ClO4)4.4H2O和TbReLL′2(ClO4)4.nH2O(Re:掺杂离子,n=2,3,4)。对苯二甲酸的羧基氧与稀土离子以对称螯合双齿配位;部分高氯酸在内界以单齿配位;配合物含有水分子。配合物的相对荧光光谱测定表明,相同配体的铽系列配合物的荧光强度明显强于铕系列。稀土离子Eu3 的5D0能级为17250cm-1,Tb3 的5D4能级为20430cm-1,而配体对苯二甲酸的三重态能级为25160cm-1,高于Eu3 和Tb3 离子的激发态能级,满足配合物分子内传能配体的三重态能级高于稀土离子发射能级的条件,可以提高Eu3 和Tb3 离子的特征荧光强度。但相对于Eu3 离子,对苯二甲酸的三重态能级与Tb3 离子的激发态能级(5D4)更匹配,更有利于能量的有效传递,因此,铽系列的荧光强度明显强于铕系列。Ho3 、Yb3 对Eu3 离子发光敏化作用最强,Ce3 、Sm3 、Dy3 、Er3 对Eu3 离子发光也有敏化作用,Pr3 、Nd3 离子对Eu3 离子的发光是猝灭的;Yb3 、Dy3 离子对Tb3 离子发光有较强敏化作用,而Ce3 、Pr3 、Nd3 、Sm3 、Ho3 、Er3 离子的掺入对Tb3 离子的发光是猝灭的。应用分子内能量传递过程对发光机理进行了探讨。     

柠檬酸-凝胶法合成ZnGa2O4:Mn2+/Eu3+及其发光性能的研究

采用柠檬酸－凝胶法合成了纯的ZnGa2O4粉末以及ZnGa2O4:Mn^2 /Eu^3 粉末,利用X射线衍射（XRD）、热重及差热分析（TG－DTA）、发光光谱等测试手段对ZnGa2O4和ZnGa2O4:Mn^2 /Eu^3 的结晶过程、发光性质进行了研究。XRD结果表明,柠檬酸－凝胶法合成的样品在500℃。发光光谱测试表明ZnGa2O4:Mn^2 在450nm和506nm处出现两个发射带,前者属于ZnGa2O4基质的发射,后者属于Mn^2 的^4T1→^6A1的跃迁发射。ZnGa2O4:Eu^3 则呈现Eu^3 的特征红光发射,最强峰位于613nm,属于Eu^3 的^5D0→^7F2超灵敏跃迁。通过光谱分析进一步证实了ZnGa2O4:Mn^2 /Eu^3 的发光机理是基质敏化,吸收能量并向激活离子传递能量。     

稀土配合物RE(TPTZ)Cl_3的合成、表征及荧光性能研究

首次以2,4,6-三吡啶基三嗪（TPTZ）与Sm, Eu, Tb和Dy氯化物反应,合成四种单一稀土配合物以及Tb分别1∶1掺Gd, Y, La的三种异核配合物。经元素分析、稀土络合滴定、摩尔电导率、红外光谱、紫外光谱和差热-热重测定表明,配合物的组成分别为RE（TPTZ）Cl3·3H2O（RE=Sm, Eu, Tb, Dy）和Tb0.5Ln0.5（TPTZ）Cl3·3H2O（Ln=Gd, Y, La）;TPTZ作为三齿配体与稀土离子配位,即中心环提供一个N原子,两个吡啶环分别提供一个N原子;配合物中3个水分子与稀土离子配位,1个Cl-在外界,2个在内界,为1∶1型电解质;配合物内外界可能为[RE（TPTZ）（H2O）3Cl2] Cl,稀土离子的配位数为8。配合物的荧光光谱测试表明,四种单一稀土配合物中,Tb配合物发光最强;三种1∶1掺杂异核Tb配合物荧光强度大于纯Tb配合物,表明Y3＋, La3＋和Gd3＋都可以敏化Tb3＋的发光,其中Gd3＋的敏化作用最强,Y3＋次之,La3＋最差。     

苯并咪唑取代胺及其配合物光谱分析

本文阐述了用原子吸收光谱测定三（2－苯并咪唑亚甲基）胺和二（2－苯并咪唑亚甲基）胺与Cu2 的配合物中心原子,并对上述配体及配合物用紫外光谱法和红外光谱法进行了研究,从而解释了配合物分子结构。     

稀土配合物分子内能量传递和弛豫过程的光声和荧光光谱研究

将光声光谱和荧光光谱两种互补的手段结合起来 ,从无辐射跃迁和辐射跃迁两个角度讨论了固态稀土配合物的激发 弛豫过程。测定了稀土配合物 (Tb(AA) 3·2H2 O、Tb(AA) 3bpy和Tb(AA) 3phen)固体粉末的光声光谱和荧光光谱。与荧光光谱相结合 ,光声光谱反映了不同配合物发光效率的变化 ,Tb(AA) 3phen、Tb(AA) 3·2H2 O和Tb(AA) 3bpy的发光效率依次增强。研究了配合物的分子内能量传递和弛豫过程 ,配体最低三重态能级与稀土离子共振能级之间的能级差是否匹配是配体敏化中心离子发光的关键因素     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.