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81.
Jacky Cresson 《随机分析与应用》2018,36(2):224-239
We discuss a method, which was popularized by E. J. Allen and that is frequently used in applications to construct SDE models. The derivation procedure is based on information about the elementary processes involved in the dynamics and their corresponding probabilities. We formulate criteria for the viability of the resulting models. In particular, explicit necessary and sufficient conditions are deduced for the non-negativity and/or boundedness of solutions. Moreover, we show that the class of deterministic models for which the construction leads to an admissible SDE extension is strongly limited. Several examples are presented to illustrate the implications of our results. 相似文献
82.
K. Veselinov F. Grillot M. Gioannini I. Montrosset E. Homeyer R. Piron J. Even A. Bekiarski S. Loualiche 《Optical and Quantum Electronics》2008,40(2-4):227-237
In this paper, a theoretical model is used to investigate the lasing spectrum properties of InAs/InP (113)B quantum dot (QD) lasers emitting at 1.55 μm. The numerical model used is based on a multi-population rate equation (MPRE) analysis. It takes into account the effect of the competition between the inhomogeneous broadening (due to the QD size dispersion) and the homogenous broadening as well as a nonlinear gain variation associated to a multimode laser emission. The double laser emission and the temperature dependence of lasing spectra of self-assembled InAs/InP quantum dot lasers is studied both experimentally and theoretically. 相似文献
83.
Wang J Even MA Chen X Schmaier AH Waite JH Chen Z 《Journal of the American Chemical Society》2003,125(33):9914-9915
In this Communication, we demonstrate the novel observation that it is feasible to collect amide signals from polymer/protein solution interfaces in situ using sum frequency generation (SFG) vibrational spectroscopy. Such SFG amide signals allow for acquisition of more detailed molecular level information of entire interfacial protein structures. Proteins investigated include bovine serum albumin, mussel protein mefp-2, factor XIIa, and ubiquitin. Our studies indicate that different proteins generate different SFG amide signals at the polystyrene/protein solution interface, showing that they have different interfacial coverage, secondary structure, or orientation. 相似文献
84.
The fully optimized geometry of the activated complex which occurs as an intermediate in the concerted H-transfer reaction between C2H4 and cis-N2H2 has been determined using the ab initio FORCE method of Pulay. The activation energy for the synchronous transfer of two hydrogen atoms from cis-N2H2 to ethylene is found to be 18.8kcal/mol, i.e. substantially lower than the previously estimated energy barrier of around 60 kcal/mol. The same method applied to trans-N2H2 and semilinear N2H2 gave an isomerization energy of 49.7 kcal/mol indicating that the isomerization of trans-N2H2 to the cis form might be the overall rate-controlling step. 相似文献
85.
Chengcheng Zhou Meijuan Jiang Jian Du Haotian Bai Guogang Shan Ryan T. K. Kwok Joe H. C. Chau Jun Zhang Jacky W. Y. Lam Peng Huang Ben Zhong Tang 《Chemical science》2020,11(18):4730
Visually identifying pathogens favors rapid diagnosis at the point-of-care testing level. Here, we developed a microenvironment-sensitive aggregation-induced emission luminogen (AIEgen), namely IQ–Cm, for achieving fast discrimination of Gram-negative bacteria, Gram-positive bacteria and fungi by the naked-eye. With a twisted donor–acceptor and multi-rotor structure, IQ–Cm shows twisted intramolecular charge transfer (TICT) and AIE properties with sensitive fluorescence color response to the microenvironment of pathogens. Driven by the intrinsic structural differences of pathogens, IQ–Cm with a cationic isoquinolinium moiety and a membrane-active coumarin unit as the targeting and interacting groups selectively locates in different sites of three pathogens and gives three naked-eye discernible emission colors. Gram-negative bacteria are weak pink, Gram-positive bacteria are orange-red and fungi are bright yellow. Therefore, based on their distinctive fluorescence response, IQ–Cm can directly discriminate the three pathogens at the cell level under a fluorescence microscope. Furthermore, we demonstrated the feasibility of IQ–Cm as a visual probe for fast diagnosis of urinary tract infections, timely monitoring of hospital-acquired infection processes and fast detection of molds in the food field. This simple visualization strategy based on one single AIEgen provides a promising platform for rapid pathogen detection and point-of-care diagnosis.A simple AIEgen with three emission colors achieves rapid identification of Gram-negative bacteria, Gram-positive bacteria and fungi. 相似文献
86.
Tunable laser two-photon ionization of aniline cooled in supersonic expansions combined with TOF mass spectrometry reveal an isotopic shift of the vibronic origin at 2938 Å (ππ1; 1B2←1A1 transition). The shift (+4.6 cm?1) is smaller than the rotational bandwidth and would be unobservable by laser-induced fluorescence. 相似文献
87.
Li Z Dong Y Mi B Tang Y Häussler M Tong H Dong Y Lam JW Ren Y Sung HH Wong KS Gao P Williams ID Kwok HS Tang BZ 《The journal of physical chemistry. B》2005,109(20):10061-10066
We synthesized a group of silole regioisomers 1(x,y), whose photoluminescence varied dramatically with its regiostructure. By internally hindering the intramolecular rotation, we succeeded in creating a novel silole (1(3,4)) that is strongly luminescent in solutions and whose fluorescence quantum yield in acetone is as high as 83%. We revealed that 1(3,4) was a sensitive chemosensor capable of optically discriminating nitroaromatic regioisomers of p-, o-, and m-nitroanilines. Against general belief, crystal formation of 1(2,4) blue-shifted its emission color and boosted its emission efficiency. The light-emitting diode based on the crystal of 1(2,4) emitted a strong blue light (464 nm) in a high current efficiency (5.86 cd/A). 相似文献
88.
Yi Xiong Jiajie Zeng Bin Chen Jacky W. Y. Lam Zujin Zhao Shuming Chen Ben Zhong Tang 《中国化学快报》2019,30(3):592-596
New aggregation-induced emission molecules of carbazole-substituted siloles are prepared, based on which efficient non-doped OLEDs are fabricated, offering high external quantum efficiencies of up to 5.63%. 相似文献
89.
SYNTHESIS AND PHOTOLUMINESCENCE OF AN ANTHRACENE-CONTAINING HYPERBRANCHED POLY(ARYLENEETHYNYLENE) 总被引:1,自引:0,他引:1
Yong-qiang Dong Zhen Li Jacky W. Y. Lam Yu-ping Dong Xin-de Feng Ben-zhong Tang 《高分子科学》2005,(6):665-669
A hyperbranched poly(aryleneethynylene) containing anthracene chromophore was synthesized by palladiumcatalyzed cross-coupling reaction of 2,4,6-triiodophenyl 9-anthracenylcarboxylate with 9,9-bis[4-(2-propynyloxy)phenyl]- 9H-fluorene. The structure and properties of the polymer are characterized and evaluated by NMR, IR, UV, PL and TGA analyses. The polymer is soluble in common organic solvents, possesses high thermal stability (Td 〉 330℃), and emits a strong blue light of 465 nm in both solution and solid states. 相似文献
90.
Anne-Marie Alquie-Redon Jacky Vigneron Claude Lamy 《Journal of Electroanalytical Chemistry》1978,92(2):163-177
The kinetic behaviour of a two-step sequential reaction including a 2nd order adsorption process is treated theoretically in the case of semiconductor electrodes. It is shown that the electronic structure of the semiconductor can be taken into account in some simplified cases by introducing a formal transfer coefficient comprised between 0 and 1 and potential independent. In both linear potential sweep voltammetry and steady state cyclic voltammetry, the usual characteristic features (EM, M, iM) of the voltammetric curves are calculated as a function of the sweep rate for different values of the transfer coefficient. 相似文献