Search

Benzoic acid (C6H5COOH) is selected as a coal-based model compound, and its catalytic pyrolysis mechanisms on ZnO, γ-Al2O3, CaO, and MgO catalysts are studied using density functional theory (DFT) compared to the non-catalytic pyrolysis mechanism. DFT calculation shows that the pyrolysis process of C6H5COOH in the gas phase occurs via the direct decarboxylation pathway (C6H5COOH → C6H6+ CO2) or the stepwise decarboxylation pathway (C6H5COOH → C6H6COO → C6H6+ CO2). For C6H5COOH catalytic pyrolysis on the ZnO (101̅0) surface, the preferred reaction pathway is C6H5COOH → C6H5COO + H → C6H6+ CO2, whereas the preferred reaction pathway on γ-Al2O3(110), CaO (100), and MgO (100) surfaces is C6H5COOH → C6H5COO + H → C6H5+ CO2+ H → C6H6+ CO2, indicating that the presence of catalysts changed the pyrolysis mechanism of C6H5COOH. In addition, dissociative adsorption of C6H5COOH is observed on these surfaces. It is found that ZnO (101̅0), MgO (100), and CaO (100) are beneficial to C6H5COOH decomposition, but γ-Al2O3(110) is disadvantageous to the C6H5COOH decomposition. At the same reaction temperature, the rate constants show the order: k(ZnO) > k(MgO) > k(CaO) > k(no catalyst) > k(γ-Al2O3).

This paper proposed a separated-frequency identification method of Li-ion battery model for Electric Vehicles (EVs). The main idea is to decompose the measured terminal voltage and current data in wavelet domain, and then the weighting least squares (LS) algorithm is used to extract the model parameters. Since the signal energy of open circuit voltage (OCV) mainly distributes in the low frequency band, the identifiable wavelet-domain battery model can be approximately obtained by neglecting the high frequency wavelet decomposition coefficients. Furthermore, based on the Akaike’s information criterion, we study the optimum decomposition order of the wavelet-domain battery model.

The bandwidth and the dynamic range is the critical performance parameter of IF AGC (Intermediate Frequency Automatic Gain Control) in wireless receiver. In order to design broadband and large dynamic range IF AGC circuit, the main functions and performance of the VGA (Variable Gain Amplifier) AD8367 and the logarithmic amplifier AD8318 are analyzed. A kind of a broadband large dynamic range IF AGC module is designed by using these two chips. Detail circuit is provided; key technology of AGC module is analyzed and the actual testing results are offered. Compared to the traditional AGC circuit, the module is simple; it has small size and obvious advantages in broadband and large dynamic range.

Through analyzing the development of Social-security system, the paper proposes one design proposal of the WEB system development based on LINQ. It uses three-tier structure to carry on the system development and carry on the operation for the database by LINQ. The applications of system prove that the system is operating well. It improves the management level of social-security information and it also confirms LINQ could greatly simplify the programming efficiency of system development and improve the access speed of database.