最新刊期
卷 9 ， 期 3 ， 1988
- 摘要：We have investigated systematically the interaction between Er3+ ions in ZnS:Er3+ and ZnS:ErF3 thin films. In this paper, we will investigated the effect of annealing on the AC electroluminescence (ACEL) of ZnS:ErF3 thin films.The devices arc ITO-Y2O3-ZnS:ErF3-Al structure.The devices were prepared by sequential depositions of Y2O3 insulating layer, ZnS:ErF3 emission iaytr and Al electrode onto an indium tin-oxide(lTO) coated glass plate. The deposition of Y2O3 and ZnS:ErF3 layers were carried out by electron-beam evaporation.The thickness of Y2O3 and ZnS:ErF3 layers are 300nm and 500nm, respectively. Before Al electrode were evaporated, the samples were annealed in N2 atmosphere. The annealing conditions were 200℃,300℃,400℃ and 500℃ for two hours, and 2,4,6,8,10 an d12 hours at 500℃,respectively.99|35|0更新时间：2020-08-11
- 摘要：This paper investigates the ESR spectra of ZnS:Mn, Cu and ZnS:Cu and their dependence on doing, annealing and ageing of samples. ESR Spectra and Concentration QuenchingThe line shape of ESR spectra of ZnS:Mn, Cu powder samples changes with increasing Mn2+ ion concentration. When the Mn2+ ion concentration is as low as 0.1% (g/g),the spectra of isolated Mn2+ ions have six hyperfine lines. As Mn2+ ion concentration grows larger than 0.3% (g/g), the six hyperfine lines gradually merge into an envelope. At a high concentration as 1.5% (g/g), spectrum appears as a structureless single line with a narrower half-width. It has been suggested that the formation of Mn2+ pairs and clusters and hence the exchange-coupling ion are the cause of line enveloping and its width narrowing.112|50|0更新时间：2020-08-11
- 摘要：LaOBr:Tb and LaOCl:Tb are efficient cathodo-and x-ray phosphors.They have the type of structure as PBFC1 and consist of alternative layers of La-O-La-X-La. Their tetragonal unit cell is shown in Fig.1[1]. Each La3+ ion is 9-coordinated by 4 oxide ions on one side and 5 halide, ions on the other side. Four halide ions locate at equal distance to La3+ and the fifth one locates further. The doped Tb3+ ions replace the La3+ ions in a point site of C4v symmetry. Holsa and coworkers have studied the splitting of the ground 7Fj stats of Tb3+ in LaOCl matrix[2]. The authors have investigated the physico-chemical properties and luminescence of LaOBr1-xClx:Tb system in detail[3]. The lattice constants a and c change linearly with the composition x. This shows that the system forms complete solid solution.101|35|0更新时间：2020-08-11
- 摘要：The radiative transition probabilities of Dy3+ and Sm3+ in orate bglasses have been calculated. The nonradiative transition probabilities and the quantum efficiencies have also been estimated from the obtained radiative transition probabilities and the measured decay times.The oscillator strengthes for electric dipole and magnetic dipole transitions in absorption process are expressed as Ped and Pmd in Eq.l.The magnetic dipole transition matrix elements can be calculated using the intermediate-coupling wave functions expressed as linear combinations of LS basis and the reduced matrix elements given by Eq. 3. On the basis of Judd-Ofelt theory, intensity parameters can be obtained from experimental absorption oscillator strtngthes Pex and Eq. 1 by solving some linear equations on the parameters.143|59|0更新时间：2020-08-11
- 摘要：The spectroscopic properties of the solid solutions(1-x) CeMgAl11O19-xSrAl12O19:Mn2+ are reported. The fluorescent spectra of Mn2+ in the solid solutions consist of two emission bands, a green band peaked at with 516nm and a red band, the peak position of which depends on x, with 685nm for x=0 and 630nm for x=0.8. The green band arised from Mn2+ centers in tetrahedral 4f sites (denoted as Mn2+ (g)) and the red band originated from Mn2+ ions in octahedral 2a position (Mn2+(r)).The fluorescence decay analysis and excitation spectra indicated that the energy transfer from Mn2+ (g) to Mn2+(r) occurred in the solid solutions (1-x) CeMgAl11O19-xSrAl12O19 doped with higher Mn2+ concentration (≥0.4mole).114|23|0更新时间：2020-08-11
- 摘要：The sensitized fluorescence oi binary and ternary complexes of RE(Eu, Tb)has been studied by the Fluorescence Titration Method, the sensitizers used being mainly β-diketones and aromatic amines.Rare earth europium and terbium, each has its own characteristic fluorescence spectra (Em). With the change of the ligands constituting the complexes, the position of the Em peaks of the RE ions remains basically unchanged whereas their intensities and shapes show some variation.The Eu complexes have two distinct fluorescence peaks in general, corresponding to electric dipole transition(ED)of 610 nm and magnetic dipole transition (MD) of 587 nm.The ratio MD/ED reflects the symmetry of the environment of the RE ions (the smaller the ratio, the less the symmetry).The MD/ED of Eu-|S-diketones complex has been deter-dmined≈0.125, and the MD/ED of Eu-o-phenanthrolein or Eu-2.2'dipyri-dine complex≈0.5.The symmetry of the former is less than that of the latter. The closeness of the MD/ED ratio of the complexes of the same kind means that they have the similarity in the numbers of the ligands cholating on RE ion, their occupation position and the structure of chelates.The spectra of excitation(Ex) of the RE complexes are also related to the kind of ligands. The Ex shapes of Eu-β-diketone complexes are similar each other, they have two peaks, one strong and one weak.More difference exists in the case of Eu-aro-matic amine complexes, but their common point is that each of them has three peaks.The Ex between different kind of complexes are still more different.The above phenomena also reflect that the structure and property of the chelating ligand function group linking RE ion are directly related to the fluorescence spectra of the complexes.106|55|0更新时间：2020-08-11
- 摘要：The fluorescence of Bi3+ has been found to bt efficient in Ca2YSbO6 host. In this paper, the luminescent properties of Bi3+ in Ca2YSbO6 compounds with monocline structure and the regularities of their variation are reported for the first time. Under 315nm excitation, Ca2YSbO6:Bi show very strong emission (blue-purple) with a broadband spectrum extending from 350-470nm and peaking at 400nm. The fluorescence at 400nm is belong to 3P1-1S0 electron transition. In Ca2Y1-xBixSbO6 phosphor, the fluorescent intensities of Bi3+ enhance with the increase of the Bi3+ concentration till 0.04 molecule. Probably,Ca2Y0.96Bi0.04SbO6 will bt used for phosphor powder in black light and for a light source to synthesis vitamine c in the future if the experiment on it is done futher.116|73|0更新时间：2020-08-11
- 摘要：The splittings of Eu3+ levels are sensitive to the field of the surrounding ions. In order to identify the local symmetry of La3+ ions in Na2Ca6Ia2(PO4)6F2 lattice,, spectroscopic study using Eu3+ as a probe was carried out.For Eu3+ in Na2Ca6Ia2(PO4)6F2, observed numbers of emission lines are 1,4 and 3 for 5D0-7F0, 7F1 and 7F2 transitions respectively. The results indicate that Eu3+ ions occupy two nonequivalent sites with D3h and C6 symmetries.Eu3+ ions substitute La3+ in Na2Ca6Ia2(PO4)6F2, hence we conclude that La3+ ions are with D3h or C6 local symmetries.96|38|0更新时间：2020-08-11
- 摘要：X-ray double crystal topography method with non-parallel asymmetrical (+, -) setting and the study on GaAs/AlGaAs epitaxial crystal are given in this paper. The diffracted effects of bending crystal plane resulted from epitaxy are analysed.From the topographies of substrate and epitaxial layers on MBE, misfit dislocations, line dislocations, growth hillock, defects from pollution and misorientation are discussed.The origination and developement of defects and dislocations are explained from the processes and principle. It is found that the MBE growth GaAs/AlGaAs epitaxy can be improved by the insert of a serial strain super lattices.101|65|0更新时间：2020-08-11
- 摘要：Chemiluminesctnce from alveolar macrophages is caused by phagocytosis. It had been enhanced by adding luminol and measured on a liquid scintillation counter. The quartz and CaCO3 particles was injected into SD rats by trachea respectively. Animals were anesthetized with sodium pentobarbitol and exsar-guinated by cutting the abdominal arota. Alveolar macrophages were harvested by pulmonary lavage in situ with medium. The results are showed as follows.The relationship of the concentration of alveolar macrophages, luminol, and zymosan with the intensity of CL was investigated. The best assay system is that a) alveolar macrophagts arc 2×106ce.ll/ml.b) luminol is 2×10-4M, and c) zymosan is 1×108/ml. The dynamic change of CL from alveolar macrophages in rats after exposing to particles was monitored and showed that alveolar macrophagts of the rats exposed to quartz and CaCO3 varied distinctly with one of normal rats on phagocyte-luminescence. It can respond to the toxicity of particles. The results, are showed that the intensity of CL was descended with the time of exposure to particles. The intensity of CL was used to determine phagocytic function of alveolar macrophages and early damage in organism. It is significant to research pathogeny of pncumoconisis.109|66|0更新时间：2020-08-11
- 摘要：The etching behaviour of InP in two chemical etching system is studied with negative Kpp and positive AZ1350J mask in the various concentration Br2:CH3OH and Br2:HBr:H2O system, respectively. Etching rate versus Br2 concentration as well as etching depth versus etching timt is given.These two etching system are very stable for temperature fluctuation. They are available by using negative Kpp and positive AZ135J as resistant mask.The sample surface needn't be coated by sputtered SiO2 or Si3N4 film as protection mask, it is very convenient to fabricate InP optoelectrical devices. The dependence of etching rate of sample on Br: concentration and etching profiles of sample on crystal orientation are properly explained from the viewpoint of crystallography.162|70|0更新时间：2020-08-11
- 摘要：Spectral measurement on selected 7-aminocoumarin derivatives demonstrates that both their absorption and fluorescence emission in a variety of solvents exhibit no detectable change in spectral profile upon addition of certain organic compounds such as phenyl halides, benzene, toluene and cyclohexane. In several cases,however,the fluorescence intensity and lifetime are increased, accompanied by a small shift of emission peak to shorter wavelength, and this fluorescence enhancement is clearly depended on the substitution pattern of aminocoumarin at 7-position as well as on the solvents used,i.e,the fluorescence enhancement can be observed for coumarin with rotatable amino substituent in polar solvents. As a typical example, the fluorescence intensity of 4-trifluoromethyl-7-diethyl-aminocoumarin in methanol is enhanced by a factor of two upon addition of 1,5M phenyl iodide, which is contrary to the general consideration of so-called external heavy atom effect. Moreover, the similar enhancement is also observed in tht presence of compounds without halogen atom, although the fluorescence intensity increases in a lesser extent. This finding can not be interpreted in terms of changing polarity of the solvent due to addition of this compounds, otherwise it. becomes difficult to understand why a different enhancement can be observed in the presence of phenyl halides of the same polarity at the same concentration,although it is not excluded tht possible contribution from changing polarity of the medium in general,particularly,when the compounds of low polarity are used as the additives. On the other hand, the dependence of observed fluorescence enhancement on both the substitution pattern of aminocoumarins and the solvents used leads us to realise this unexpected phenomenon by an argument based on the possible effect of additive on the dynamic equilibrium between the excited cou-marin molecules in fluorescent intramolecular charge transfer state(ICT) and its non-emissive rotamer with twisted conformation(TICT), which have been suaggested by us and G.Jones to be established for nonrigid aminocoumarins in polar solvents. In this connection we postulate that the formation of inter-molecular charge transfer complex between excited aminocoumarin and additive molecule shifts the dynamic equilibrium to the fluorescent ICT state.This postulate for understanding the fluorescence enhancement observed is verified by the kinetic analysis of relevant species decay and the dependence of the observed fluorescence enhancement on the oxidation potential cf the additive used.92|48|0更新时间：2020-08-11
- 摘要：The porphines with different number of p-aminophenyl substituents including 5-(p-aminophenyl)-10,15,20-triphtnylporphine;5-10-di(p-aminophenyl) -15,20-diphenylporphine; 5,15-di(p-aminophenyl)-10,20-diphenylporphine; 5, 10,15-tri(p-aminophenyl)-20-phenylporphine and 5,10,15,20-tetra (p-ami-nophenyl)porphine have been synthesized.Their absorption,fluorescence spectra as well as fluorescence lifetimes have been measured. The results obtained reveal that substitution-induced change in molecular symmetry has a detectable effect on their spectral as well as temporal characteristics. The reduction of molecular symmetry leads to an increase in oscillator strength and an accelaration in fluorescence decay and this substitution effect manifests more clearly for the symmetry-forbidden A1g?B2u and A1g?B3n transitions. This finding implies that the asymmetrical substitution even in the groups which do not interact much with the chromcphore seems to be able to relax the symmetry restriction posed on the electronic transitions as well.116|41|0更新时间：2020-08-11
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