Cai X.,Guizhou University for Nationalities
Guangxue Xuebao/Acta Optica Sinica | Year: 2011
When two optical fields interact with a four-level N type atom, there are three transitions and the middle transition is used as a probe transition. The two field are called coupled fields and probe field. Two cases of electromagnetically induced transparency (EIT) are discussed. When the frequency changes with time in sinusoidal form, the frequency of electromagnetically induced transparency won't change but the degree of EIT will change with time periodically. When the frequency changes with time in rectangular form, the frequency will change, the frequency shift can be calculated by the formula proposed in the article. The amplitude of EIT changing with time periodically-energy increases when the modulation amplitude of these rectangular pulses is increased.
Shao Y.H.,Guizhou University for Nationalities
Environment, Energy and Applied Technology - Proceedings of the 2014 3rd International Conference on Frontier of Energy and Environment Engineering, ICFEEE 2014 | Year: 2015
The traditional finance theory based on rational investors and the efficient market hypothesis was difficult to make a reasonable explanation to the phenomenon of fluctuation and crash in the stock market. These phenomena were formed by the behavior of investors transaction by transaction. That is, the behavior characteristics of investors had important influence on the abnormal phenomenon of the stock market fluctuation. In this paper, the investor behavior was analyzed. The model of investor decision based on prospect theory was built, which is more in line with the process of human practical decision-making. At the same time, the artificial stock market model was constructed combined with the agent-based computational finance method. Finally, the model was verified by the simulation program of Object-c based on Swarm. The study explores intrinsic formation mechanism of stock price volatility from the perspective of behavioral finance, in order to put forward some valuable suggestions for the risk management of investor and the policy regulation of regulatory. © 2015 Taylor & Francis Group, London.
Stokes J.L.,University of Bristol |
Yu Y.,University of Bristol |
Yuan Z.H.,Guizhou University for Nationalities |
Pugh J.R.,University of Bristol |
And 3 more authors.
Journal of the Optical Society of America B: Optical Physics | Year: 2014
This paper introduces the novel concept of a cross dipole nanoantenna for use in fluorescence based sensing applications. The dual-arm nature of the cross nanoantenna allows a dual resonant structure to be designed such that the shorter arm resonates with the pump wavelength and the longer arm with the emission wavelength. This is expected to further enhance emission from any fluorescent molecule that can couple to both nanoantenna arms when compared with a singly resonant structure. The paper uses the finite-difference time-domain method to first analyze the two-arm nanoantenna case and then shows how intensity enhancement depends on the antenna geometry and tapering of arms in the antenna gap. The results show that smaller gap sizes always produce larger enhancement compared with lightning rod effects due to tapering. A four-arm cross nanoantenna is then studied, highlighting differences from the two-arm case. Finally, the effect of a diagonally aligned molecule transiting the central gap region is studied. The results show that two hotspots occur on either side of the central gap region when the molecule is aligned perpendicular to the transit direction and only a single central hotspot occurs when the alignment is parallel to the transit direction. © 2014 Optical Society of America.
Fu W.,Luoyang Normal University |
Guo W.,Luoyang Normal University |
Zou G.,Guizhou University for Nationalities |
Xu C.,Luoyang Normal University
Journal of Fluorine Chemistry | Year: 2012
A convenient and efficient method for oxidative coupling of tetrahydroisoquinoline derivatives with trimethyl(trifluoromethyl)silane and terminal alkynes to 1-trifluoromethylated or 1-alkynylated tetrahydroisoquinolines via CH activation was developed using visible light irradiation. The protocol uses Rose Bengal as the catalyst, air as terminal oxidant, and the trifluoromethylation or alkynylation was selectively performed at the α-position of nitrogen under extremely mild conditions. © 2012 Elsevier B.V. All rights reserved.
Du H.,South China University of Technology |
Du H.,Guizhou University for Nationalities |
Ye J.,South China University of Technology |
Zhang J.,Tianjin University of Technology |
And 2 more authors.
Journal of Electroanalytical Chemistry | Year: 2011
In this report, a voltammetric sensor for simultaneous determination of hydroquinone (HQ) and catechol (CC) was developed at a glassy carbon electrode modified with graphene (GR/GCE). The separation of oxidation and reduction peak (ΔE) is decreased from 281 to 31 mV for HQ and from 250 to 26 mV for CC at GR/GCE, respectively. Separation of the oxidation peak potentials for HQ and CC was about 112 mV in 0.10 M acetate buffer solution (pH 4.5), and the anodic currents for the oxidation of both HQ and CC are greatly increased at GR/GCE, which makes it suitable for simultaneous determination of these compounds. Under the optimized condition, the anodic peak current of HQ is linear with the concentration of HQ from 1 × 10-6 to 5 × 10-5 M in the presence of 5 × 10-5 M CC. A detection limit of 1.5 × 10-8 M (S/N = 3) can be achieved. At the same time, the anodic current of CC is linear with the concentration of CC from 1 × 10-6 to 5 × 10-5 M with a detection limit of 1.0 × 10-8 M (S/N = 3) in the presence of 5 × 10-5 M HQ. The proposed sensor was successfully applied to the simultaneous determination of HQ and CC in tap water, and the results are satisfactory. © 2010 Elsevier B.V. All rights reserved.