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31.
M. E. Bashtanov N. N. Drozdova A. A. Krasnovskii 《Journal of Applied Spectroscopy》1999,66(4):550-555
The relative intensity of photosensitized phosphorescence of singlet oxygen (1O2) at 1270 nm (L1270) and1O2-induced delayed fluorescence (Ldf) of bacteriopheophytin a (BPh) (770 nm) in air-saturated solutions of BPh in hexafluorobenzene in excitation by 337-nm pulses
of a nitrogen laso is investigated. It is established that Ldf≪L1270. The ratio of the initial intensity of delayed fluorescence and phosphorescence of1O2(Ldf)0/(L1270)0 changed from 0.02 to 0.30 as a function of the energies of laser pulses (2.5–5.0 mJ/cm1) and the BPh concentration (6–18 μM). As the index of quantum efficiency of the delayed fluorescence, the authors used the
coefficient
where [1O2]0 is the initial concentration of1O2 after the laser burst; [Bpn] is the concentration of BPh; kr is the constant of the rate of1O2 radiative deactivation in the solvent under study; γf is the quantum yield of BPh fluorescence. It is established that this
coefficient is smaller by a factor of ∼2000 than in phthalocyanine, while its absolute value is ∼2·1010M−2sec−1. The saturation of BPh solutions with oxygen at atmospheric pressure is shown to lead to a fivefold attenuation of the delayed
fluorescence as compared to air-saturated solutions. The possibility of BPh triplet molecules being involved in the radiation
of delayed fluorescence of the pigment is discussed.
Reported at the VIIIth International Conference on Spectroscopy of Porphyrins and Their Analogs, Minsk, September 22–26, 1998.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 504–508, July–August, 1999. 相似文献
32.
V.?V.?BryukhanovEmail author A.?M.?Ivanov I.?G.?Samusev 《Journal of Applied Spectroscopy》2005,72(6):804-808
The processes of homo-and hetero-triplet—triplet annihilation (TTA) of Bengali rose on the spongy silicon surface have been
investigated. It has been found that upon pulse photoexcitation on the silica surface photophysical processes involving the
triplet states of monomers and their associates can develop. It has been shown that the processes of hetero-TTA are inhibited
due to the decomposition of associates under the influence of hexane molecules in the molecular clusters of the dye adsorbates.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 734–737, November–December, 2005. 相似文献
33.
The intermolecular vibrational energy transfer from triplet molecules of benzophenone and anthraquinone to H2O molecules has been investigated. To determine the rates of establishment of vibrational (V-V) and thermal (V-T) equilibrium in a vibrational quasi-continuum of mixed singlet-triplet levels, the dependences of the decay rates and intensities of the fast and slow components of delayed fluorescence on the H2O vapor pressure have been investigated. For V-V relaxation, the efficiencies 1 and the mean energies E transferred per collision in mixtures with H2O and other polyatomic foreign gases have been compared. It has been established that the efficiencies 1 for quasi-resonant vibrational energy transfer (V-V) from benzophenone and anthraquinone to H2O are an order of magnitude lower than the gas-kinetic ones and lower than those obtained under the same experimental conditions for such foreign gases as C5H12, SF6, and CCl4, and decrease with increasing temperature in the 433–513 K range. It has been concluded that the mechanism of V-V relaxation in mixtures with H2O are determined by long-range attractive forces. In mixtures with H2O, no acceleration of V-T relaxation due to the formation of hydrogen bonds has been revealed. The low-efficiency thermalization process (V-T relaxation) is controlled by short-range repulsive forces, and the differences between the intensities 2 for mixtures of benzophenone and anthraquinone with H2O and other polyatomic gases are determined by the change in the reduced mass of interacting molecules. 相似文献
34.
Fei?Zhangchfli@whu.edu.cn" title="zhangfei@.com chfli@whu.edu.cn" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author Chengfang?Li Lina?Shi 《Optical and Quantum Electronics》2004,36(15):1253-1261
We study a Si-based diode with a p+nn+ structure for picosecond semiconductor closing switch and discuss the physical process, which underlies the operation principle of high-power closing switch based on a delayed breakdown diode (DBD). From the results of numerical simulations and theoretical analysis, single device has demonstrated reliable operation at 2.3 kV, 89 ps risetime, and high output dV/dt(30 kV/ns). As a contribution to the optimal design, some conclusions about trade-off are drawn by changing structure parameters and physical parameters. 相似文献
35.
Sample path large and moderate deviation principles for Markov modulated risk models with delayed claims are proved by the exponential martingale method. As applications, asymptotic estimates and exponential bounds of the ruin probability are also studied. 相似文献
36.
In this paper, we propose a design method of guaranteed cost controllers for uncertain large-scale systems with time delays in subsystem interconnections using delayed feedback. Using the Lyapunov method, a linear matrix inequality (LMI) optimization problem is formulated to design a delayed feedback controller which minimizes the upper bound of a given quadratic cost function. A numerical example is included to illustrate the design procedures.Communicated by Q. C. ZhaoThe authors thank the Associate Editor and three anonymous referees for careful reading and useful suggestions. 相似文献
37.
In this paper, blue thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have been elucidated, with a focus on the degradation characteristics of the emission layer (EML). The operational stability against electrical stress was investigated for two host materials and four doping concentrations, which were used as the EML. The operating stability of the devices was confirmed by comparing the peak capacitance before and after degradation. Devices using bis [2-(diphenyl-phosphino) phenyl] ether oxide (DPEPO) as a host exhibited poor degradation characteristics. However, high stability was confirmed when 3,3-di (9H-carba-zol-9-yl)-biphenyl (mCBP) was used. DPEPO host devices are most resistant against performance degradation when they are doped with 10 wt% 10,10'-(4,4′-sulfonylbis(4,1-phenylene))bis(9,9-dimethyl-9,10-dihydroacridine (DMAC-DPS). We successfully determined the electroluminescence characteristics of the device depending on the host material, as well as the doping concentration, using the capacitance–voltage method. 相似文献
38.
Ziwen Jiang Yongsheng Zhao Zhixun Luo Aidong Peng Hao Wang Prof. Dr. Jiannian Yao 《中国化学》2010,28(11):2103-2108
Doped nanoparticles were prepared from pyrene and phenanthrene using a facile reprecipitation method. The doped nanoparticles presented unique delayed fluorescent emissions of pyrene under the unprotected condition. The ratio of the intensity of delayed fluorescence (IDF) to that of phosphorescence (IP) is about 4:1, which almost keeps unchanged with the decrease of pyrene content at room temperature. The intensity of the delayed fluorescence emissions is dependent on the relative content of pyrene, as well as the aggregation degree of nanoparticles. The delayed emissions are contributed to efficient triplet‐triplet energy transfer from phenanthrene (donor) to pyrene (acceptor). Steady fluorescence measurement have proved that the singlet‐singlet energy transfer process was also existent dominated by the radiation energy transfer mechanism. 相似文献
39.
Robust decentralized adaptive synchronization of general complex networks with coupling delayed and uncertainties
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The problem of robust decentralized adaptive synchronization of general complex networks with coupling delayed and uncertainties is investigated in this article. It is only assumed that the upper normal bound of uncertain inner and outer coupling matrices is positive but its concrete structure is not also required to be known. The time‐varying coupling delay is a any nonnegative continuous and bounded function and not require its derivative to be less than one, that is, general time‐varying coupling delays and uncertainties. For such a class of uncertain complex networks, a new synchronization scheme is presented by a class of continuous memoryless robust decentralized adaptive synchronization controllers. It is also shown that the synchronization error dynamics of uncertain complex networks can be guaranteed as uniformly exponentially convergent toward a ball that can be as small as desired. Finally, numerical simulations are provided to demonstrate the effectiveness and robustness of proposed complex networks synchronization schemes. © 2013 Wiley Periodicals, Inc. Complexity 19: 10–26, 2014 相似文献
40.
像计算机、电视机、空调等这类具有物理变质的可能性很小,但生命周期较短、不断更新换代、价值不断贬值的电子产品会发生无形变质的现象.在假设无形变质率与需求率负相关,同时在产品的存储过程中,考虑库存水平对销售量的影响情况下,研究需求受库存水平影响、且缺货时存在延迟订货的短生命周期物品的库存管理问题.创新之处在于考虑了产品的缺货问题;在允许缺货的条件下,建立了短生命周期物品的库存模型;运用数值算例进行了求解和验证;并对各参数进行了敏感性分析. 相似文献