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Xiangtan, China

Hunan University of Science and Technology is an institution of higher learning in Xiangtan, Hunan Province of the People's Republic of China. It is under the jointly jurisdiction of central government and provincial government, and is mainly administered by Hunan Province. Hunan University of Science and Technology was formed by the merger of two earlier universities. Wikipedia.

Liu Q.,Hunan University of Science and Technology
Macromolecular Chemistry and Physics | Year: 2010

Monodisperse hyper-crosslinked polystyrene nanospheres with ultrahigh specific surface area were successfully prepared by emulsifier-free miniemulsion polymerization and post-cross- linking. The specific surface area and the total pore volume of hyper-crosslinked nanospheres were increased with increasing the concentration of vinybenzyl chloride in monomer mixture. The hyper-crosslinked nanospheres exhibited excellent swelling capacity in thermodynami- cally good and poor solvent. Furthermore, the nanospheres with specific surface area of 1223 m2 g-1 adsorbed 2.13wt.-% hydrogen at 163K/1.5MPa. Overall, the present study provided a simple method to prepare mono- disperse microporous hyper-crosslinked polymer nanospheres. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Zong-Chang Y.,Hunan University of Science and Technology
International Journal of Electrical Power and Energy Systems | Year: 2012

Electric load forecast analysis has become increasingly important for the industry. Climate factors are the ones of key factors influencing the load demand. The sun is vital for attributing climate change as the earth is moving (revolution, rotation) in its elliptical orbit around the sun. The paper introduces an elliptic orbit algorithmic model for yearly and daily electric load movement analysis. In the proposed model, electric load movement as a time series is mapped to the polar coordinates to build the algorithmic model that the angular coordinate represents time, and the radial coordinate donates its corresponding electric load. The built model with its elliptical orbit is used for load movement analysis. The proposed approach is applied to yearly load movement evaluation and forecast for State Gird Corporation of China (SG) and its five branches in 2006, and daily load movement evaluation and forecast for one daily load of Shanghai Grid. The experiments yield results agreeing well with their actual loads. The results indicate workability of the proposed. © 2012 Elsevier Ltd. All rights reserved. Source

Dai J.,Hunan University of Science and Technology
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2013

Million watt scale directly-driven wind turbines are chosen as the study object and its dynamic characteristics are analyzed at the condition of a blade fracture accident happening. By integrating the wind rotor loads sub-model, electromechanical coupling sub-model and pitch control sub-model, the system models of wind turbines are obtained. In the wind rotor loads sub-model, not only the aerodynamic force but also the inertia force and gravity force are considered; in the pitch actuator sub-model, the dynamic characteristics are considered. According to the established wind turbine models, the corresponding numerical simulation models are constructed in Simulink; the simulation is carried out assuming that wind turbines have yet to be stopped after a few seconds of blade fracture. The research results show that when a blade fracture happening, the wind rotor mechanical rotational torque mutates. Since the generator electromagnetic torque tracks quickly the wind rotor mechanical rotational torque, the wind rotor rotating speed remains near the given value. Furthermore, the energy capture and conversion of wind turbines is out of balance; the DC capacitor voltage, the active power and reactive power injected into the grid have dramatic fluctuations which has impact on the grid. Through the research, the dynamic characteristics of wind turbines are obtained when a blade fracture happening which can provide useful reference for wind turbine structure design, operation control, etc. © 2013 Journal of Mechanical Engineering. Source

Yang Z.-C.,Hunan University of Science and Technology
Environmental Science and Pollution Research | Year: 2014

Nowadays, the issue of air pollution has continuously been a global public health concern. Modeling and forecasting daily movement of ambient air mean PM2.5 concentration is an increasingly important task as it is intimately associated with human health that the air pollution has unignorable negative effects in reducing air quality, damaging environment, even causing serious harm to health. It is demonstrated that daily movement of mean PM2.5 concentration approximately exhibits weekly cyclical variations as daily particle pollution in the air is largely influenced by human daily activities. Then, based on weekly quasi-periodic extension for daily movement of mean PM2.5 concentration, the called elliptic orbit model is proposed to describe its movement. By mapping daily movement of mean PM2.5 concentration as one time series into the polar coordinates, each 7-day movement is depicted as one elliptic orbit. Experimental result and analysis indicate workability and effectiveness of the proposed method. Here we show that with the weekly quasi-periodic extension, daily movements of mean PM2.5 concentration at the given monitoring stations in Xiangtan of China are well described by the elliptic orbit model, which provides a vivid description for modeling and prediction daily movement of mean PM2.5 concentration in a concise and intuitive way. © 2014 Springer-Verlag Berlin Heidelberg. Source

Huang B.,Nanjing Audit University | Li H.-X.,Nanjing University | Wei D.-K.,Hunan University of Science and Technology
Knowledge-Based Systems | Year: 2012

Intuitionistic fuzzy information systems are generalized types of conventional fuzzy-valued information systems. By introducing a dominance relation to intuitionistic fuzzy information systems, we propose a notion of dominance intuitionistic fuzzy information systems (DIFIS) and establish a dominance-based rough set model, which is mainly based on the substitution of the indiscernibility relation in classic rough set theory by a dominance relation that is defined on the score and accuracy function of intuitionistic fuzzy value in DIFIS. Furthermore, to simplify the knowledge representation and extract useful and simpler dominance intuitionistic fuzzy rules, we provide two attribute reduction approaches to eliminate the redundant information. Finally, we apply these approaches to computer auditing risk assessment, and by using an application as a case study we acquire some valuable assessment rules. These resulting rules can provide an available method to acquire knowledge from DIFISs. © 2011 Elsevier B.V. All rights reserved. Source

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