希夫碱配合物M3L3(NO3)6(H3O)2的合成与光谱性质

以4-氨基-1,2,4-三氮唑与对二甲氨基苯甲醛为原料, 在冰醋酸催化下合成了配体4-氨基-1,2,4-三氮唑缩对二甲氨基苯甲醛（L）。 然后利用L与过渡金属硝酸盐［M(NO3)2·xH2O(M=Cu,　Co,　Zn,　Cd; x=3～6)］在无水乙醇中反应, 制得固态配合物M3L6(NO3)6(H2O)2。 通过元素分析、 红外光谱、 紫外光谱、 荧光光谱等手段对合成的配体及配合物进行了表征。 实验结果表明, 该物质是一种多晶粉末状的发光材料,　在紫外光的激发下,　在乙醇溶液体系中的荧光发射峰在416 nm处,　为蓝色荧光, 色纯度高,　荧光量子效率高, 而配合物M3L6(NO3)6(H2O)2的荧光发射峰则红移至445 nm左右, 同时荧光强度显著增强。　M3L6(NO3)6(H2O)2中与M(Ⅱ)发生配位作用的基团是配体中三氮唑环上的氮原子。     

希夫碱配合物M3L6(NO3)6(H2O)2的合成与光谱性质

以4-氨基-1,2,4-三氮唑与对二甲氨基苯甲醛为原料,在冰醋酸催化下合成了配体4-氨基-1,2,4-三氮唑缩对二甲氨基苯甲醛(L).然后利用L与过渡金属硝酸盐[M(NO3)2·xH2O(M=Cu,C0,Zn,Cd;x=3～6)]在无水乙醇中反应,制得固态配合物M3L6(NO3)6(H2O)2.通过元素分析、红外光谱、紫外光谱、荧光光谱等手段对合成的配体及配合物进行了表征.实验结果表明,该物质是一种多晶粉末状的发光材料,在紫外光的激发下,在乙醇溶液体系中的荧光发射峰在416 nm处,为蓝色荧光,色纯度高,荧光量子效率高,而配合物M3L6(NO3)6(H2O)2的荧光发射峰则红移至445 nm左右,同时荧光强度显著增强.M3L6(NO3)6(H2O)z中与M(Ⅱ)发生配位作用的基团是配体中三氮唑环上的氮原子.     

钴配合物[Co(phen)(pydc)(H2O)]·2H2O的合成、表征及荧光性质

采用溶剂挥发法合成了钴配合物[Co(phen)(pydc)(H2O)]· 2H2O,通过元素分析、红外光谱、紫外光谱、热重和X-射线单晶衍射对其结构进行了表征.该化合物属于三斜晶系,Pi空间群.六配位的Co(Ⅱ)为畸变的八面体构型.单胞分子间通过氢键及π-π堆积作用相互形成三维网状结构.荧光测试表明配合物在369nm(λmax)具有强的荧光发射.     

三维超分子化合物[Zn(H_2O)_6]·(C_(16)H_8O_8)的合成、晶体结构及荧光光谱

以醋酸锌和3,3’,4,4’-联苯四羧酸(H4BPTC)为原料,采用水热法合成了一个三维超分子化合物[Zn(H2O6)].(C16H8O8)(1)。通过红外光谱、元素分析和X射线单晶衍射对其结构进行了表征,X射线单晶衍射分析结果表明,该超分子化合物属于三斜晶系,PT空间群,晶胞参数a=0.654 8(1)nm,b=0.793 9(2)nm,c=0.968 1(2)nm,α=76.29(3)°,β=87.75(3)°,γ=86.43(3)°,Z=1,R1=0.066 5,wR2=0.183 3,GOF=1.021.并通过荧光光谱研究了1在溶液和固态时的发光性能,在室温DMSO溶液中,当激发波长为316nm时,化合物1在399nm处有一强发射峰,呈现蓝紫色荧光,在室温固态时,该化合物的发射峰发生明显红移,在525nm处有一宽谱带发射峰,呈现绿色荧光,这可以归因于在固态化合物1的分子中存在氢键和π—π堆积的相互作用,可以明显降低分子中基态与激发态之间的能量差距,从而使发射峰红移。     

三维超分子配合物[Zn（C_（12）H_8N_3）_2·H_2O]的水热合成、晶体结构及光致发光1

通过水热法合成了一种三维超分子配合物Zn（C12H8N3）2.H2O,经元素分析、紫外和红外光谱对其进行表征。用X射线单晶衍射测定了其晶体结构,该配合物晶体属单斜晶系,P21/c空间群,晶胞参数为：a=1.25239（10）nm,b=1.30233（11）nm,c=1.33167（11）nm,β=102.6950（10）°,Z=4,[Zn（C12H8N3）2.H2O],Mr=471.81,V=2.1189（3）nm^3,Dc=1.479g·cm^-3,μ=1.189mm^-1,F（000）=968,R1=0.0300,WR2=0.1017,GOF=1.005。该化合物由1个Zn（Ⅱ）离子、2个2-（2-吡啶基）苯并咪唑阴离子和1分子配位水组成。其中2-（2-吡啶基）苯并咪唑的1位氮原子、吡啶环上氮原子及水分子中氧原子与锌（Ⅱ）离子配位,形成五配位的畸变三角双锥结构,单胞分子之间通过氢键O（w）-H…N和π-π堆积作用相互构成三维网状超分子体系。固态荧光测试显示,该配合物具有强的蓝色荧光发射（λmax=456nm）。     

紫光化合物[Cd(bpdc)(phen)_2(H_2O)]·6H_2O的合成、结构及荧光光谱研究

以2,4′-联苯二甲酸(H2bpdc)和1,10-邻菲罗啉(phen)为配体,采用水热法合成一例三维超分子网状镉(Ⅱ)配合物[Cd(bpdc)(phen)2(H2O)]·6H2O(1)。通过单晶X射线衍射分析,元素分析和红外光谱分析表征化合物1的结构。单晶X射线衍射分析结果表明,化合物1属于三斜晶系,P1空间群,中心金属Cd(Ⅱ)离子呈现六配位扭曲八面体构型,通过两种氢键作用和π—π堆积作用形成三维超分子结构。同时,对化合物1进行固态/溶液以及不同温度下的荧光性能测试。以350nm为激发波长进行激发,298K固态时,化合物1在390nm处有强发射峰,呈现紫色荧光;77K固态时,化合物1的荧光光谱具有两个发射谱带,分别位于380和520nm处,是因为在低温时化合物1表现出精细结构。298K时,化合物1在DMSO溶液和CH3OH溶液中分别在380和375nm有最大发射,相对于固态最大发射波长发生蓝移,呈现紫色荧光。这均是基于中心金属微扰配体中心的π*→π跃迁发射。研究了化合物1固态和溶液的荧光寿命,化合物1荧光衰减过程包含双组分。298K条件下,化合物1在DMSO溶液中的寿命(τ1=1.73μs和τ2=14.07μs)比CH3OH溶液中的荧光寿命(τ1=1.21μs和τ2=12.44μs)长。此外,77K固态时的荧光寿命(τ1=1.96μs和τ2=16.11μs)长于298K的固态荧光寿命(τ1=1.20μs和τ2=11.34μs),这是因为低温条件下降低分子内部的非辐射跃迁,从而延长固态荧光寿命。     

紫光化合物［Cd(bpdc)(phen)2(H2O)］·6H2O的合成、结构及荧光光谱研究

以2,4′-联苯二甲酸(H2bpdc)和1,10-邻菲罗啉(phen)为配体, 采用水热法合成一例三维超分子网状镉(Ⅱ)配合物［Cd(bpdc)(phen)2(H2O)］·6H2O (1)。通过单晶X射线衍射分析, 元素分析和红外光谱分析表征化合物1的结构。单晶X射线衍射分析结果表明, 化合物1属于三斜晶系, P1空间群, 中心金属Cd(Ⅱ)离子呈现六配位扭曲八面体构型, 通过两种氢键作用和π—π堆积作用形成三维超分子结构。同时, 对化合物1进行固态/溶液以及不同温度下的荧光性能测试。以350 nm为激发波长进行激发, 298 K固态时, 化合物1在390 nm处有强发射峰, 呈现紫色荧光;77 K固态时, 化合物1的荧光光谱具有两个发射谱带, 分别位于380和520 nm处, 是因为在低温时化合物1表现出精细结构。298 K时, 化合物1在DMSO溶液和CH3OH溶液中分别在380和375 nm有最大发射, 相对于固态最大发射波长发生蓝移, 呈现紫色荧光。这均是基于中心金属微扰配体中心的π*→π跃迁发射。研究了化合物1固态和溶液的荧光寿命, 化合物1荧光衰减过程包含双组分。298 K条件下, 化合物1在DMSO溶液中的寿命(τ1=1.73 μs和τ2=14.07 μs)比CH3OH溶液中的荧光寿命(τ1=1.21 μs和τ2=12.44 μs)长。此外, 77 K固态时的荧光寿命(τ1=1.96 μs和τ2=16.11 μs)长于298 K的固态荧光寿命(τ1=1.20 μs和τ2=11.34 μs), 这是因为低温条件下降低分子内部的非辐射跃迁, 从而延长固态荧光寿命。     

一个Schiff碱配体的镍和锌配合物的合成及晶体结构

合成了两个含邻甲氧基苯甲醛Schiff碱配体的单核过渡金属配合物:Ni (C15H13N2O3)2 (1)和Zn (C15H13N 2O3)2(2).采用元素分析和单晶X-射线衍射对制备的晶体进行了结构表征.结构分析表明,这两个配合物属于异质同晶,晶体属四方晶系,空间群为P41212,Z=4.镍原子和锌原子都形成了扭曲的八面体配位构型.配体的酚氧原子(O1和O1A)未与金属原子配位,而甲氧基的氧原子(O3和O3A)却与金属原子配位.     

三元配合物H[Ni（C7H4O4）（C9H6NO）]·2.5H2O的合成与表征

以2,4-二羟基苯甲酸和8-羟基喹啉为配体,以Ni2+作为中心原子,合成了一种新的三元固体配合物H[Ni(C7H4O4)(C9H6NO)]·2.5H2O,并采用元素分析、IR光谱和TG-DSC分析对它的结构进行了表征。结果表明,在该配合物中,2,4-二羟基苯甲酸配体以羧基O原子和一个羟基O原子与中心原子配位,8-羟基喹啉配体以羟基O原子和喹啉N原子与中心原子配位,配合物的配位数为4。     

2,9-二正丁基-1,10-菲咯啉双核铜(Ⅰ)配合物的合成、晶体结构及光学性质

以2,9-二正丁基-1,10-菲咯啉(dnbp)和碘化亚铜为原料,在四氢呋喃溶液中反应合成了一种新型中性双核铜(Ⅰ)配合物[CuI(dnbp)]2。采用X射线单晶衍射、核磁共振氢谱、紫外-可见吸收光谱表征其结构,荧光光谱测定其发光性能。结果表明:该配合物分子由两个Cu(Ⅰ)离子通过两个碘离子桥联形成畸变的菱形Cu2I2核心和dnbp螯合配体构成,配合物中I—Cu—I的夹角较小(106.08°),两个Cu(Ⅰ)离子的距离很长(0.319 4 nm),表明它们的相互作用可以忽略。上述结构的特征主要由dnbp配体大的空间位阻造成。配合物晶体属于三方晶系,空间群为R-3,晶胞参数a=4.404 14(11)nm,b=4.404 14(11)nm,c=1.085 92(4)nm,γ=120°,V=18.241 1(9)nm3。配合物在二氯甲烷溶液中出现350～500 nm的吸收峰,归属于金属离子到配体的电荷转移跃迁(MLCT)。室温下,当激发波长为365 nm时,其最大发射波长为653 nm,发光寿命为3.1μs,光致发光量子产率为0.013。发光机制属于金属离子和卤素到配体电荷转移激发态的磷光发射。低温下,配合物最大发射波长蓝移至645 nm,发射峰变窄。     

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.