Zhang J.,Guizhou Normal College
Electrochimica Acta | Year: 2010
Amperometric detection of tolazoline (TL) was carried out on a gold nanoparticles (AuNPs)/poly-o-aminothiophenol (PoAT)-modified electrode by a molecular imprinting technique and electropolymerization method. The modification procedure was characterized via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The recognition between the imprinted sensor and target molecule was observed by measuring the variation of amperometric response of the oxidation-reduction probe, K3Fe(CN)6 on electrode. Under the optimal experimental conditions, the peak currents were proportional to the concentrations of tolazoline in two ranges of 0.05-5.0 μg mL-1 and 5.0-240 μg mL-1 with the detection limit of 0.016 μg mL-1. Meanwhile the prepared sensor showed sensitive and selective binding sites for tolazoline. The enhancement of sensitivity was attributed to the presence of AuNPs which decreased the electron-transfer impedance. © 2010 Elsevier Ltd. All rights reserved.
Liang J.-X.,Tsinghua University |
Liang J.-X.,Guizhou Normal College |
Li J.,Tsinghua University
Nature Communications | Year: 2015
The electroreduction of water for sustainable hydrogen production is a critical component of several developing clean-energy technologies, such as water splitting and fuel cells. However, finding a cheap and efficient alternative catalyst to replace currently used platinum-based catalysts is still a prerequisite for the commercialization of these technologies. Here we report a robust and highly active catalyst for hydrogen evolution reaction that is constructed by in situ growth of molybdenum disulfide on the surface of cobalt diselenide. In acidic media, the molybdenum disulfide/cobalt diselenide catalyst exhibits fast hydrogen evolution kinetics with onset potential of-11 mV and Tafel slope of 36 mV per decade, which is the best among the non-noble metal hydrogen evolution catalysts and even approaches to the commercial platinum/carbon catalyst. The high hydrogen evolution activity of molybdenum disulfide/cobalt diselenide hybrid is likely due to the electrocatalytic synergistic effects between hydrogen evolution-active molybdenum disulfide and cobalt diselenide materials and the much increased catalytic sites. © 2015 Macmillan Publishers Limited. All rights reserved.
Schroter M.,University of Rostock |
Ivanov S.D.,University of Rostock |
Schulze J.,University of Rostock |
Polyutov S.P.,University of Rostock |
And 4 more authors.
Physics Reports | Year: 2015
The influence of exciton-vibrational coupling on the optical and transport properties of molecular aggregates is an old problem that gained renewed interest in recent years. On the experimental side, various nonlinear spectroscopic techniques gave insight into the dynamics of systems as complex as photosynthetic antennae. Striking evidence was gathered that in these protein-pigment complexes quantum coherence is operative even at room temperature conditions. Investigations were triggered to understand the role of vibrational degrees of freedom, beyond that of a heat bath characterized by thermal fluctuations. This development was paralleled by theory, where efficient methods emerged, which could provide the proper frame to perform non-Markovian and non-perturbative simulations of exciton-vibrational dynamics and spectroscopy. This review summarizes the state of affairs of the theory of exciton-vibrational interaction in molecular aggregates and photosynthetic antenna complexes. The focus is put on the discussion of basic effects of exciton-vibrational interaction from the stationary and dynamics points of view. Here, the molecular dimer plays a prominent role as it permits a systematic investigation of absorption and emission spectra by numerical diagonalization of the exciton-vibrational Hamiltonian in a truncated Hilbert space. An extension to larger aggregates, having many coupled nuclear degrees of freedom, becomes possible with the Multi-Layer Multi-Configuration Time-Dependent Hartree (ML-MCTDH) method for wave packet propagation. In fact it will be shown that this method allows one to approach the limit of almost continuous spectral densities, which is usually the realm of density matrix theory. Real system-bath situations are introduced for two models, which differ in the way strongly coupled nuclear coordinates are treated, as a part of the relevant system or the bath. A rather detailed exposition of the Hierarchy Equations Of Motion (HEOM) method will be given in terms of a stochastic decoupling ansatz. This method has become the standard in exciton-vibrational theory and illustrative examples will be presented as well as a comparison with ML-MCTDH. Applications will be shown for generic model systems as well as for small aggregates mimicking those formed by perylene bisimide dyes. Further, photosynthetic antenna complexes will be discussed, including spectral densities and the role of exciton-vibrational coupling in two-dimensional electronic spectroscopy. © 2014 Elsevier B.V.
Zheng J.,Guizhou University |
He L.,Guizhou Normal College
Metallurgical and Mining Industry | Year: 2015
In this article, a segment planning method has been proposed especially for the requirement of the random compensating angle in the rotating cylinder transmission system. Firstly, the article has established the constraint condition of the angle compensation according to the position correcting principle of the rotating cylinder, and proposed the segment planning method composed by rough compensation and finish compensation, designed the work mechanism of the controller in different segments. The study has derived the function of S shape acceleration and deceleration process based on the segment planning method, defined the planning coefficient which effects the segmentation and the dynamic characteristics of the cylinder, proved the feasible region of the planning coefficient is 0.58~0.70, and provide the optimized method of the planning coefficient in feasible region based on the basic idea of the compensating method. Simulation results show that this method can both get a gentle and symmetrical acceleration-deceleration curve and abundant finish compensating time for diverse initial velocity and compensating angle. © Metallurgical and Mining Industry, 2015.
Lou X.,Guizhou Normal College
Lecture Notes in Electrical Engineering | Year: 2013
Generally, constructivism can be classified into a great number of small genres, and social constructivism is one of its very important genres. The knowledge-based concept, teaching concept, and learning concept, which are proposed in the social constructivism, can exert great enlightenments for people to make an improvement to classroom teaching. In this paper, the author carries out an introduction on the intension of the social constructivism teaching concept first, and discusses its great enlightenments on the new curriculum reform of China. Therefore, this paper is of practical and guiding significance to some extent. © 2013 Springer-Verlag.
Xiao T.,Guizhou Normal College
ChemPhysChem | Year: 2015
The electrostatic part of the solvation energy has been studied by using extended Debye-Hückel (DH) theories. Specifically, our molecular Debye-Hückel theory [J. Chem. Phys. 2011, 135, 104104] and its simplified version, an energy-scaled Debye-Hückel theory, were applied to electrolytes with strong electrostatic coupling. Our theories provide a practical methodology for calculating the electrostatic solvation free energies, and the accuracy was verified for atomic and diatomic charged solutes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Bai S.,Anhui University of Science and Technology |
Wang C.,Anhui University of Science and Technology |
Deng M.,Anhui University of Science and Technology |
Deng M.,Guizhou Normal College |
And 4 more authors.
Angewandte Chemie - International Edition | Year: 2014
Surface charge state plays an important role in tuning the catalytic performance of nanocrystals in various reactions. Herein, we report a synthetic approach to unique Pt-Pd-graphene stack structures with controllable Pt shell thickness. These unique hybrid structures allow us to correlate the Pt thickness with performance in the hydrogen-evolution reaction (HER). The HER activity increases with a decrease in the Pt thickness, which is well explained by surface polarization mechanism as suggested by first-principles simulations. In this hybrid system, the difference in work functions of Pt and Pd results in surface polarization on the Pt surface, tuning its charge state for hydrogen reduction. Meanwhile, the supporting graphene provides two-dimensional channels for efficient charge transport, improving the HER activities. This work opens up possibilities of reducing Pt usage while achieving high HER performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Development of novel molecularly imprinted magnetic solid-phase extraction materials based on magnetic carbon nanotubes and their application for the determination of gatifloxacin in serum samples coupled with high performance liquid chromatography
Xiao D.,China Pharmaceutical University |
Dramou P.,China Pharmaceutical University |
Xiong N.,Guizhou Normal College |
He H.,China Pharmaceutical University |
And 3 more authors.
Journal of Chromatography A | Year: 2013
A novel composite imprinted material, on the basis of magnetic carbon nanotubes (MCNTs)-incorporated layer using gatifloxacin as a template, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a cross-linker, was successfully synthesized by a surface imprinting technique. Adsorption dynamics and a Scatchard adsorption model were employed to evaluate the adsorption process. The results showed that magnetic carbon nanotubes molecularly imprinted polymers (MCNTs@MIP) displayed a rapid dynamic adsorption and a high adsorption capacity of 192.7μg/mg toward GTFX. Applied MCNTs@MIP as a sorbent, a magnetic solid phase extraction method coupled with high performance liquid chromatography (MSPE-HPLC) was developed for the determination of GTFX in serum samples. The recoveries from 79.1. ±. 4.8% to 85.3. ±. 4.2% were obtained. MCNTs@MIP can not only be collected and separated fast by external magnetic field but also have high surface-to-volume ratio, outstanding mechanical properties and specific recognition toward template molecule. In addition, the MCNTs@MIP could be regenerated, which could be used for five cycles with lost of less than 7.8% of its recovery on average. These analytical results of serum samples display that the proposed method based on MCNTs@MIP is applicable for fast and selective extraction of therapeutic agents from biological fluids. © 2012 Elsevier B.V.
Yan Y.-A.,Guizhou Normal College |
Zhou Y.,Guizhou Normal College
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015
It remains a challenge for theory to simulate nonperturbative and non-Markovian quantum dissipative dynamics at low temperatures. In this study we suggest a Hermitian non-Markovian stochastic master equation suitable for dissipative dynamics at arbitrary temperatures. The memory effect of the bath is embedded within two real correlated Gaussian noises. This scheme is numerically verified by the hierarchical equation of motion and symmetry preserving for a symmetric two-level system. An exemplary application is carried out for the dynamics over a broad range of temperatures to investigate the temperature dependence of the Rabi frequency shift and the non-Markovianity. © 2015 American Physical Society.
Zhang J.,Nanjing University |
Zhang J.,Guizhou Normal College |
Lei J.,Nanjing University |
Ju H.,Nanjing University |
Wang C.,Guizhou Normal College
Analytica Chimica Acta | Year: 2013
A newly designed molecularly imprinted polymer (MIP) was synthesized and successfully utilized as a recognition element of an amperometric sensor for 2,4-dichlorophenol (2,4-DCP) detection. The MIP with a well-defined structure could imitate the dehalogenative function of the natural enzyme chloroperoxidase for 2,4-DCP. Imprinted sensor was fabricated in situ on a glassy carbon electrode surface by drop-coating the 2,4-DCP imprinted microgel suspension and chitosan/Nafion mixture. Under optimized conditions, the sensor showed a linear response in the range of 5.0-100μmolL-1 with a detection limit of 1.6μmolL-1. Additionally, the imprinted sensor demonstrated higher affinity to target 2,4-DCP over competitive chlorophenolic compounds than non-imprinted sensor. It also exhibited good stability and acceptable repeatability. The proposed sensor could be used for the determination of 2,4-DCP in water samples with the recoveries of 96.2-111.8%, showing a promising potential in practical application. © 2013 Elsevier B.V.