Advanced Materials Research Vols. 347-353

Abstract: DEA technique is widely used for efficiency evaluation of Decision Making Unit (DMU) with multiple inputs and outputs. This paper applies DEA model to the study of the efficiency of environmental pollution treatment in 8 provinces including Hebei and neighboring or Maritime Provinces. The results show that the efficiency of Efficiency of Environmental Pollution Control in Hebei Province is not high. Environmental pollution improvement in Hebei Province still needs to be expanded.

Abstract: In order to reduce the pressure drop increase caused by self-rotating plastic twisted-strips in heat transfer tubes of vacuum condensers in thermal power plant, the twisted strips structure is optimized. There are holes distributed in twisted strip uniformly. The holes diameter and interval are optimized through experimental research. The results show that when holes diameter is less than 6mm, holes can reduce the pressure drop increase at low flow velocity while the pressure drop with holes is greater than that without holes at high flow velocity. The holes diameter is 4~5mm when the pressure drop is the lowest. The pressure drop with holes is always larger than that without holes when holes diameter is more than 6mm. The pressure drop will increase as holes interval decreases at high flow velocity, while it will reduce at low flow velocity.

Abstract: Fe-Mn oxide and Ce-doped Fe-Mn oxide nanosized particles were studied on the structural and catalytic activities for SCR. The catalysts were characterized by TEM, TPR and BET study. Analysis data show that the addition of Ce improves the reduction performance of Fe-Mn species. It was found that the Ce promoted samples exhibited much better activities for SCR of nitric oxide with ammonia because of the promotion of the structural and redox properties.

Abstract: The background of urban renewal in Xi’an inner city in 1990s is introduced by 4 parts, and the drive force is demonstrated in the first instance. Based on the above, the entire process is compartmentalize three phases to be described. Finally, based on the shortage of the urban renewal, new strategic thinking was put forward to resolve the current problems.

Abstract: The generalized differential transform method is implemented for solving time-fractional partial differential equations in fluid mechanics. This method is based on the two-dimensional differential transform method (DTM) and generalized Taylor’s formula. Results obtained by using the scheme presented here agree well with the numerical results presented elsewhere. The results reveal the method is feasible and convenient for handling approximate solutions of time-fractional partial differential equations.

Abstract: Two types of activated carbons were produced by chemical activation respectively with and without pre-carbonization procedure, and were used in organic electrolyte supercapacitors. Galvanostatic charge and discharge results show that voltage upper limit and activated carbon type obviously influence the cycle stability of the capacitors. And cyclic voltammograms reveal the better capacitive behavior and cycle stability of the activated carbon produced with carbonization procedure implying the correlation between these two factors. While Nyquist plots disclose the tendency of equivalent circuit component parameters and electrode processes with cycling.

Abstract: The permanent magnetic spherical stepper motor model is introduced in this paper, random encoder is painted on the rotor surface, and outputs of 96 optoelectronic sensors are used to identify rotor orientation. Based on the special structure and rotational character, the paper uses an improved mutative scale chaos search algorithm to mapping the dynamics equation of chaos variable to the orientation space. When the number of either local minima or cycles is equal to the initial value, the search space is dynamically reduced. Simulation shows that the search method is simple and has ability of fast convergence to the goal orientation, thus the search efficiency is improved.

Abstract: A brief comparative study is presented regarding different exergy efficiency correlations of solar photovoltaic/thermal (PV/T) system that have been proposed in the literature. Performance evaluation results of a certain PV/T hybrid system are found to be inconsistent with each other when using different correlations of exergy efficiency. It is mainly due to that no consensus has been reached in the calculation of thermal exergy, solar radiation exergy and other causal factors. Also, the issues that need to be further investigated are briefly discussed. This study will be beneficial to the design and performance assessment of PV/T hybrid system.

Abstract: A large number of PVs can produce security and economic influence for distribution system, for its probabilistic and intermittent output. The solar radiation which PV component receives is easily influenced by clouds. The clearness index can reflect this. So a PV output stochastic model is built based on clearness index. In this paper the probabilistic output of PVs and loads are both considered and expressed by stochastic variables. A random expectation model has been built considering annual saved environment cost. The objective function is the minimum expected value of annual investment and operation cost. The operation constraints are to ensure the reliability and economy of power system. The solution algorithm is PSO combining with probabilistic power flow. Qualification rates of bus voltage and line power flow are examined after planning. At last the calculation example manifests this planning model can get good result under the condition of reflexing the probabilistic output of PVs and randomness of power loads.

Abstract: Describes the theory and methods of data mining technology, and the latest research progress home and abroad. In the equipment operation of various thermal power plants, more and more field data is stored in the DCS real-time database, and there is always an abundance of knowledge hidden behind the data. Adopting the date mining technology to process and analyze these data can optimize the operation of power plants and provide effective means for monitoring and evaluation of the equipment.