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.
Soleymani F.,Islamic Azad University at Zahedan |
Sharma R.,DAV Institute of Engineering and Technology |
Li X.,Guizhou University for Nationalities |
Tohidi E.,Ferdowsi University of Mashhad
Mathematical and Computer Modelling | Year: 2012
In this paper, we discuss iterative methods for solving univariate nonlinear equations. First of all, we construct a family of methods with optimal convergence rate 4 based upon the Potra-Pták scheme and provide its error equation theoretically. Second, by using this derivative-involved family, a novel derivative-free family of two-step iterations without memory is derived. This derivative-free family agrees with the Kung-Traub conjecture (1974) for building optimal multi-point iterations without memory, since it is proven that each derivative-free method of the family reaches the convergence rate 4 requiring only three function evaluations per full iteration. Finally, numerical test problems are also provided to confirm the theoretical results. © 2011 Elsevier Ltd.
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.
Gao H.,Northeast Forestry University |
Gao H.,Guizhou University for Nationalities |
Xie Y.,Northeast Forestry University |
Ou R.,Northeast Forestry University |
Wang Q.,Northeast Forestry University
Composites Part A: Applied Science and Manufacturing | Year: 2012
In the presented study, polypropylene (PP) and high density polyethylene (PE) were blended at the ratios of 80/20 and 20/80 to simulate recycled waste thermoplastic mixtures. The effects of in situ grafting of PP/PE blends with maleic anhydride through the extruder on the mechanical and rheological properties of resulting wood/plastic composites were investigated. Different ratios of PP and PE in the blends created distinct properties in the resulting composites. Grafting of PP and PE blends improved the tensile and flexure properties of the resulting composites. The composites exhibited a reduced water uptake and resultant dimensional swelling due to grafting with maleic anhydride. Grafting of the blends also considerably improved the interfacial bonding and enhanced the dispersion of wood in the matrix, as evidenced by rheological analysis and scanning electron microscopy. © 2011 Elsevier Ltd. All rights reserved.
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.
Jiang Q.-Q.,Guizhou University for Nationalities
Lecture Notes in Electrical Engineering | Year: 2012
The teaching quality evaluation is an important part in education evaluations. It is playing a more and more important and positive role in the course of teaching. In order to strengthen management in teaching and to improve the quality and efficiency of teaching, it is necessary to develop the system of evaluation. © 2012 Springer-Verlag London Limited.
Zhao J.,Guizhou University for Nationalities
Lecture Notes in Electrical Engineering | Year: 2012
In recent years, with the rapid development of China's hydroelectric utilities, more and more large-scale hydraulic power sets have been used. As the size and capacity of the hydraulic power sets increases, automation level raises, the possibility of faults is also increasing. The shape of shaft orbits contains a large number of fault information. Different types of faults correspond to different shape characteristics. For example, because of unbalanced rotor, the shape of shaft orbits is ellipse; because of the misalignment of shaft, the shape is banana; because of oil whirl, the shape is inner 8. Therefore, to use the shape of shaft orbits to diagnose the fault of the hydraulic power sets is a very effective method. © 2012 Springer-Verlag London Limited.
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.
Li L.,Guizhou University for Nationalities
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010
In order to supply a theoretical guide for digital chaotic telecommunication, the technique of Optical injection locking (OIL) of semiconductor lasers on the chaotic communication have been investigated based on the theoretical models used to describe the dynamics of solitary VCSEL subjected to the external optical injection and signal transmission in fiber. The numerical simulation results show that, the frequency chirp and time-resolved chirp are reduced in magnitude, using a VCSEL laser as master and another VCSEL as slave, it leads to a no-penalty transmission over 50 km of uncompensated in SSMF at 10Gb/s, and it could be higher rate and more remote if there were appropriate compensation. © 2010 SPIE.
Li R.,Guizhou University for Nationalities
Applied Mechanics and Materials | Year: 2012
In this paper we investigate the structure of the machine for high-precision radial tire production and design a new center machine with low-ring hub that can be adjusted. This new machine consists of Top Center Machine Assembly, Frame Assembly and Bottom Center Machine Assembly. The new design resolve the problem of compatibility of multi-specifications, make the procee of replacing bladder become convenient and improve the productivity of the machine. © (2012) Trans Tech Publications.