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951.
We have studied the regular patterns of the change in the electronic transition frequency in low-temperature luminescence
spectra of uranyl trinitrate and tetranitrate crystals with alkali metal cations or an NH
4
+
group as the outer-sphere cations, as a function of the ionization potential of the latter. An analogous study was carried
out as a function of the ratio of the concentrations of impurity and matrix for different cations in mixed crystals and solid
solutions. Analysis of the results obtained, together with available crystallographic data, allowed us to propose a cluster
model for the uranyl complex. The observed regular patterns are also explained from the standpoint of statistical thermodynamics.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 588–591, September–October, 2006. 相似文献
952.
D. V. Romanov N. V. Vasil’ev A. I. Lyamin N. P. Ivanovskaya N. S. Osinb 《Russian Chemical Bulletin》2006,55(2):276-280
The Claisen condensation of diesters of fluorinated dicarboxylic acids with 2-acetyl-naphthalene affords the corresponding
naphthyl-containing tetraketones and diketo esters. The luminescence-spectral properties and stability constants of complexes
of these compounds with Eu3+ ions were estimated. The characteristics of the complexes are comparable with those of fluorinated β-diketones containing
chromophoric substituents, which are widely used in luminescence analysis. The synthesized naphthyl-containing diketo esters
are efficiently conjugated with proteins and can be used for detection of biospecific interactions.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 269—273, February, 2006. 相似文献
953.
954.
电子俘获材料的光学性质及光存储机制研究 总被引:23,自引:7,他引:16
报道在硫化锶中掺入Eu、Sm和Ce、Sm两种激活剂的具有良好的光存储功能的新型光子学材料。以紫外到绿光之间不同波长的光写入信息,用近红外光读出,读出信号为橙色或绿色发光。系统的光响应速率小于20ns,写/读/擦速度快;光存储机制为电子的俘获和释放,无热效应,比目前的其他光存贮系统更优越。 相似文献
955.
I. Kh. Abdukadyrova 《Journal of Applied Spectroscopy》2003,70(6):890-895
The characteristic features of the process of radiation-defect formation and of a change in the structural and optical properties of corundum crystals exposed to reactor radiation have been investigated by spectroscopic methods. The dose dependences of the generation of a number of color and luminescence centers, the regularities of their thermal and photodecoloration, and the energies of activation of the centers have been determined. The influence of the overlapping of the absorption and luminescence centers has been estimated. The radiation-induced change in the structural parameters of the crystal and in the characteristics of the main reflexes has been determined. It has been established that at large reactor radiation fluxes the processes of damage of the crystal are accelerated and a small halo appears at 12.5°. The possible mechanism of damage and disordering of the structure of corundum irradiated in the reactor with a fairly large flux is discussed. 相似文献
956.
The optical and structural properties of mixed ZnO/MgO particles prepared by solution techniques are investigated by the cathodoluminescence and electron microscopy techniques. The samples annealed at 400–1000 °C show well crystalline wurtzite structure of the ZnO (MgZnO) particles with the size in range of 10–100 nm. Annealing at high temperatures (>700 °C) leads to Mg diffusion in ZnO and MgxZn1−xO alloy formation. The blue shifts of the near-band-edge emission as a result of the alloy band gap widening and quantum confinement effect for the small size particles are demonstrated. 相似文献
957.
958.
959.
I. M. Batyaev 《Journal of Applied Spectroscopy》1997,64(5):620-632
An attempt was made to describe and show the possibilities of new inorganic neodynium- and uranium-activated laser liquids:
SO2-GaCl3-NdCl4; SO2Cl2-GaCl3-NdCl3-UO2Cl2; POCl2-MCln-NdCl3-UO2Cl2 for development and synthesis of direct nuclear reaction-excited lasers. Luminescence data presented in the work were used
to calculate the luminescence parameters of the laser liquids such as oscillator strengths f, probability of spontaneous radiation
A, intermultiplet luminescence branching coefficient β, cross-section for induced radiation σ, luminescence decay time τ,
quantum yield η, and others. It is shown that the oscillator strengths of the normal absorption bands of Na3+, which play the main part in the pumping processes, exceed the oscillator strengths of Na3+ for aqueous and many other nonaqueous systems. In the luminescence excitation spectra of the Na3+ ion, bands are isolated in the range 400–1000 nm atλ
rec
=1.06 μm. With excitation, luminescence occurs through the4F3/2→4I9/2,11/2.13/2 channels. Luminescence spectral data are related to the lasing parameters. The threshold lasing energy is∼18 J/cm3. For a resonator with mirros h1=100% and h2=20, 40, 56, and 80%, the lasing energy is∼20–120 MJ/cm3 in the pumping energy range 18–180 J/cm3. The differential efficiency is ∼0.2% The substantial angular radiation divergence (θ∼4·10−2 rad) and strong thermostatic distortions that occur in the active element (dn/dT≈−1.9·10−4K−1) are a disadvantage of laser liquids. It is shown that operation of neodymium- and uranium-activated inorganic liquid lasers
is stable under the present conditions.
A. I. Gertsen Russian State Pedagogical University, Moika Embankment, 48, St. Petersburg, 191186, Russia. Translated from
Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 5, pp. 607–619, September–October, 1997. 相似文献
960.
本文用MOCVD技术在GaAs衬底上成功地制备了具有波导结构的Zn0.8Cd0.2Se-ZnSe应变层超晶格样品,在77K温度的光致发光光谱中观测到n=1的重空穴和轻空穴激子的辐射复合。在光泵浦下,在波导结构的F-P腔中观测到具有多模结构的受激发射,受激发射谱中的不同模具有不同的阈值功率密度;时间延迟衰减曲线的半宽度越窄,阈值光强越大. 相似文献