Chen Q.,Shanxi University |
Chen Q.,Xinzhou Teachers University |
Zhang S.-Y.,Shanxi University |
Bai H.,Shanxi University |
And 8 more authors.
Angewandte Chemie - International Edition | Year: 2015
The newly discovered borospherenes B40-/0 and B39- mark the onset of a new class of boron nanostructures. Based on extensive first-principles calculations, we introduce herein two new chiral members to the borospherene family: the cage-like C1 B41+ (1) and C2 B422+ (2), both of which are the global minima of the systems with degenerate enantiomers. These chiral borospherene cations are composed of twelve interwoven boron double chains with six hexagonal and heptagonal faces and may be viewed as the cuborenes analogous to cubane (C8H8). Chemical bonding analyses show that there exists a three-center two-electron σ bond on each B3 triangle and twelve multicenter two-electron π bonds over the σ skeleton. Molecular dynamics simulations indicate that C1 B41+ (1) fluctuates above 300 K, whereas C2 B422+ (2) remains dynamically stable. The infrared and Raman spectra of these borospherene cations are predicted to facilitate their experimental characterizations. Chiral cations: Following the recently observed C3/C2 B39- and D2d B40, two new chiral members C1 B41+ and C2 B422+ are introduced to the borospherene family. These chiral borospherene cations are composed of twelve interwoven boron double chains with six hexagonal and heptagonal faces and exhibit σ plus π double delocalization, which can be viewed as cuborenes analogous to cubane (C8H8). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Li R.,Xinzhou Teachers University |
Zhao Q.-S.,Xinzhou Teachers University
International Journal of Wireless and Mobile Computing | Year: 2017
The traditional parameter estimation methods of Hidden Markov Models (HMM) are easy to fall into local optimum, have higher requirements for initial parameter values and might result in over-coupling phenomena. In order to improve the robustness and identification performance of the model, a novel HMM parameter training method based on an improved particle swarm-ant colony algorithm (IPSAA) is presented. First, extremum disturbance is added into particle swarm optimisation algorithm (PSO) and parameters of ant colony algorithm (ACA) such as stimulating factor, volatilisation coefficients and pheromone are all improved adaptively. Second, the fitness function values of particles' history optimal solutions after PSO coarse search are used to adjust the initial pheromone distribution in fine search of ACA. Finally, Baum-Welch algorithm (B-W) is adopted to locally modify the approximate global optimal solution. The new algorithm not only solves the BW dependency on initial values and the trapped local optimum problem, but also makes full use of the global search ability of IPSAA and local development ability of B-W. The experimental results show that the system using the new algorithm is more efficient, more stable, and has better classification performance than that of traditional HMM training algorithm. Copyright © 2017 Inderscience Enterprises Ltd.
Zhao S.,Shanxi University |
Zhao S.,Xinzhou Teachers University |
Wang X.,Shanxi University |
Zhang L.,Shanxi University
RSC Advances | Year: 2013
An efficient and reusable protic-ionic-liquid solvent-catalyst system, HMTA-AcOH-H2O, has been developed and used in the Knoevenagel condensation reaction of aromatic aldehydes with ethyl 2-cyanoacetate. Under ultrasonic irradiation, the Knoevenagel condensation promoted by the protic-ionic-liquid solvent-catalyst system proceeds smoothly and cleanly. Moreover, the HMTA-AcOH-H2O solvent-catalyst system could be recycled for at least 6 times and no significant loss of activity was observed. This protocol has notable advantages, such as being eco-friendly, the ease of the work-up and reuse of the ionic liquid conveniently, which could help reduce disposal costs and contribute to the development of new catalysts for use in green and continuous chemical processes. © The Royal Society of Chemistry 2013.
Zhang H.-W.,Xinzhou Teachers University |
Xue H.-B.,Taiyuan University of Technology |
Nie Y.-H.,Shanxi University
AIP Advances | Year: 2013
The full counting statistics of electron transport through a quantum dot (QD) doped with a single magnetic impurity weakly coupled to one ferromagnetic (F) and one normal-metal lead (N) is studied based on an efficient particle-number-resolved master equation. We demonstrate that the current noise properties depend sensitively on whether the source-electrode is the ferromagnetic lead and the type of exchange coupling between the conduction electron and magnetic impurity spin. For the F-QD-N system, namely, the ferromagnetic lead as source electrode and the normal-metal lead as drain one, the super-Poissonian noise in the anti-ferromagnetic coupling case can appear; whereas for the ferromagnetic coupling case the super-Poissonian noise does not appear. As for the N-QD-F system, the super-Poissonian noise in the ferromagnetic coupling case can appear in a relatively large bias voltage range; while for the anti-ferromagnetic coupling case, the super-Poissonian noise appears only in a relatively small bias voltage range. These super-Poissonian noise characteristics can be used to reveal the type of exchange coupling between the conduction electron and magnetic impurity spin, and can be qualitatively attributed to the spin-blockade mechanism and the effective competition between fast and slow transport channels. © 2013 © 2013 Author(s).
Zhao Q.-S.,Xinzhou Teachers University |
Hu Y.-L.,Yanshan University
International Journal of Wireless and Mobile Computing | Year: 2012
This paper focuses on the node localisation in various topological and sparse wireless sensor networks. To make up for the shortcomings of the dwMDS(G) algorithm on the positioning accuracy and convergence performance, this paper proposes an improved multidimensional scaling localisation algorithm. Firstly, Multidimensional Scaling (MDS) algorithm is used to obtain the unknown nodes initial coordinates. Secondly, Particle Swarm Optimisation (PSO) algorithm is adopted to obtain the unknown nodes final coordinates by optimising the local cost function. Experimental results show that the localisation accuracy, convergence and robustness of the proposed algorithm are better than those of the existing dwMDS(G) algorithm. Copyright © 2012 Inderscience Enterprises Ltd.
Wang H.,Xinzhou Teachers University
Journal of Computational Information Systems | Year: 2011
In wireless sensor networks, node localization algorithm presently, its accuracy should be enhanced further. In this paper, the introduction of the steepest descent method as the objective function of the optimization method, this method is simple, easy to implement. Experimental results show that compared with the algorithm based SMACOF, DWMDSS has increased significantly in the algorithm accuracy, and have a relatively good performance in the anti-error effect, the convergence and convergence speed, and also performs well in the heterogeneous network. © 2005 by Binary Information Press.
Bai M.,Xinzhou Teachers University
Future Communication, Information and Computer Science - Proceedings of the International Conference on Future Communication, Information and Computer Science, FCICS 2014 | Year: 2015
International trade has become more frequent with economic globalization, but trade barriers and frictions have occasionally occurred. The work analyzed the influences of trade barriers on the current international economic situation. Based on the causes of international trade barriers, the influences were discussed in two aspects – tariff barrier and non-tariff barrier. It’s hoped to help the development of import and export trade in Chinese enterprises. © 2015 Taylor & Francis Group, London.
Cao J.,Xinzhou Teachers University |
Chen L.,Taiyuan University of Science and Technology
Computational Intelligence and Neuroscience | Year: 2015
With the advances in electronic and imaging techniques, the production of digital images has rapidly increased, and the extraction and automated annotation of emotional semantics implied by images have become issues that must be urgently addressed. To better simulate human subjectivity and ambiguity for understanding scene images, the current study proposes an emotional semantic annotation method for scene images based on fuzzy set theory. A fuzzy membership degree was calculated to describe the emotional degree of a scene image and was implemented using the Adaboost algorithm and a back-propagation (BP) neural network. The automated annotation method was trained and tested using scene images from the SUN Database. The annotation results were then compared with those based on artificial annotation. Our method showed an annotation accuracy rate of 91.2% for basic emotional values and 82.4% after extended emotional values were added, which correspond to increases of 5.5% and 8.9%, respectively, compared with the results from using a single BP neural network algorithm. Furthermore, the retrieval accuracy rate based on our method reached approximately 89%. This study attempts to lay a solid foundation for the automated emotional semantic annotation of more types of images and therefore is of practical significance. © 2015 Jianfang Cao and Lichao Chen.
Miao C.,Xinzhou Teachers University |
Li S.,Xinzhou Teachers University
Science China Chemistry | Year: 2011
A density functional theory (DFT) investigation has been performed in this work on the cage-like boron-rich boron oxide clusters B n (BO) n 2-, CB n-1(BO) n -, and C2B n-2(BO) n (n = 5-12) which are boronyl analogues of the closo-boranes B n H n 2-, monocarboranes CB n-1H n -, and dicarboranes C2B n-2H n . These boron oxide clusters possess similar geometrical and electronic structures with the corresponding boranes and carboranes and prove to be three-dimensional (3D) aromatic compounds, consistent with the previously proposed BO/H isolobal analogy. Neutral C 2B n-2(BO) n species possess considerably high ionization potentials in the range 12.0-12.7 eV and CB n-1H n - monoanions have the vertical electron detachment energies in the range 6.6-9.4 eV at the DFT level. BO terminals singly bonded to the skeletal vertexes through a B atom possess the characteristic stretching vibrational frequencies at about 2000 cm-1, clearly indicating the existence of B ≡ O triple bonds in these clusters. Experimental syntheses and characterizations of these interesting clusters may expand the structural concepts of boron oxides and bring important applications for boron oxide clusters as molecular devices in chemistry and new materials in boron neutron capture therapy. © Science China Press and Springer-Verlag Berlin Heidelberg 2011.
Guo J.-C.,Xinzhou Teachers University
Journal of Molecular Structure: THEOCHEM | Year: 2010
The structural, electronic and aromatic properties of novel sandwich complexes [M(C6Li6)2]n- (M=Nb, Ta, Mo and W; n=1, 0) containing star-like hexalithiobenzenes have been investigated by both density functional theory (DFT) and ab initio theory calculations in this work. These sandwich complexes with the staggered D6d symmetry structures are all true minimum with singlet electron state, while the D6h symmetry conformations are the transition states on the potential energy surface with one imaginary vibration frequency. The effective d-π coordination interactions between the partially filled 4d (or 5d) orbitals of transition-metal atoms and the delocalized π orbitals of the C6Li6 maintain the stabilities of these novel sandwich complexes. The centered metal of these novel sandwich complexes meet well with the 18-electron requirements. The negative NICS values for the C6Li6 ligands clearly indicated that these complexes are all aromatic in nature. The infrared (IR) spectra of these complexes have been simulated to facilitate the future experiment. These novel sandwich complexes turn out to be strongly thermodynamically favored in the gas phases and may be targeted in future experiments to expand the domain of sandwich complexes. © 2010 Elsevier B.V.