Key Engineering Materials Vols. 474-476

Abstract: Prototypes with micro-pore structure were manufactured by stereolithography technology. The prototypes were injected with mixture of wood flour as porogen and thermosetting phenolic resin as raw, then were pyrolysed after curing and prepared porous carbon templates. X-ray diffraction and scanning electron microscope were employed to analyze the phase and microstructures of the carbon templates. The pyrolysis reaction is analyzed, and the causes of the three-dimensional pore system in porous carbon template are given.

Abstract: Establishment of numerical model for hot rolled bar and analysis the changes from the discrete points on surface during the hot bar rolling process (includes velocity, displacement, equivalent stress, equivalent strain). And the position of surface defects can be effectively predicted form this. Compared with the actual hot rolling bar production, numerical simulation was in good agreement with it. So that the numerical simulation analysis has practical significance for optimizing processing parameters and process design to ensure product quality.

Abstract: The diversity of mobile terminals makes M-Commerce’s development face difficulties. Web Services technology is an application communication standards which independent from platform, component model and programming language, it can simplify the development of cross-platform application. This paper studies how to adopt Web Services-based technology to build M-Commerce platform and establishes an m-commerce platform example using the Web Services integration solutions provided by .NET Framework.

Abstract: In recent years, because the quality of chemical materials in markets exists large difference, we found concentrations of ZnCl₂ unusually high, Cl^- concentration not lower and a serious shortage of KCl concentration as using traditional methods to analyze the bath. This phenomenon occured frequent. The companies that had problems were recommended to take measures to dilute ZnCl₂ concentration range in 60 ~ 80g/l and add KCl and H₃BO₃ to the normal scope according to analysis results. However, the old problems still remained when the adjusted solution was analyzed again. The concentration of each main salt cannot be exactly determined by traditional methods because of the serious impurity contamination in the acidic galvanized solution. The concentration of ZnCl₂, KCl, H₃BO₃ in the bath were respectively tested by new analysis methods. A comparision of the results by new methods with those by traditional methods shows that the new analysis methods are simple, fast, and have low consumption, high accuracy and good effects in practical production.

Abstract: Considering a class of networked control systems built around wireless sensor networks (WSN), the control method is carried out when the output delays are present. Firstly, by studying the characteristics of data transmission with wireless sensor networks, the original system state vector was augmented, and the augmented state feedback control system was obtained. Secondly, the equation of the closed-loop control system was equal to the discrete switched system related to the hop count of the wireless transmission. Finally, a simulation example was given to demonstrate the effectiveness of the proposed method.

Abstract: Amorphous Al₂O₃ doped Er₂O₃ films were deposited on Si(001) substrates by radio frequency magnetron sputtering technique. Emission spectra exhibit a strong emission band around 410 nm and a series of emission band near 970, 980, 1018, 1042 and 1080nm. Ellipsometry measurements show that the refractive index of the ErAlO films in the region of 400～1000 nm is between 1.76-1.83. The reflectivity of the ErAlO on Si is much smaller than that of clean Si and pure Er₂O₃ films. All the results indicate that ErAlO could be a promising material for Si solar cells.

Abstract: A mismatch between the training and testing in noisy circumstance often causes a drastic decrease in the performance of speech recognition system. The robust feature coefficients might suppress this sensitivity of mismatch during the recognition stage. In this paper, we investigate the noise robustness of LPC Cepstral Coefficients (LPCC) by using speech enhancement with feature post-processing. At front-end, speech enhancement in the wavelet domain is used to remove noise components from noisy signals. This enhanced processing adopts the combination of discrete wavelet transform (DWT), wavelet packet decomposition (WPD), multi-thresholds processing etc to obtain the estimated speech. The feature post-processing employs cepstral mean normalization (CMN) to compensate the signal distortion and residual noise of enhanced signals in the cepstral domain. The performance of digit speech recognition systems is evaluated under noisy environments based on NOISEX-92 database. The experimental results show that the presented method exhibits performance improvements in the adverse noise environment compared with the previous features.

Abstract: Telecom industry, characterized by techno- economic, presents some features of scale economies and scope economies on the basic character of its natural monopoly. The question is whether it continues to exist after the reorganization of the Telecom industry. This paper mainly analyzes the features of scale economies and scope economies after the reorganization of China Unicom on the application of transcendental logarithmic cost function to show the existence of scale economies and scope economies after the reorganization.

Abstract: In the test system of intelligent munition, a test module of insulation resistance has been designed using the test resource of the system. The test module used virtual instrument technology,database technology and modularization method.It optimizes allocation of resources and simplifies hardware design. It has a good human-computer conversational enviroment and it is easy to operate and record for users. Introduced measuring methods of insulation resistance,designed hardware and measuring circuit,developed test software and realized the test data storage and management by using database technology.It realized automatic test.

Abstract: A possible virtual dynamics method is developed to replenish the wheel-track contact force histories for assessing properly the vehicles dynamics-fatigue properties under unknown real railway line spectrum. The work starts from known partial on-line inspection data of the force histories and the two known referenced line spectra, i.e. American railway line spectra of grades V and VI. The inspected data are used for selecting a closer line spectrum to real one from the two known spectra, and then, for verifying the developed method. The closer one is determined by comparing the predicted force histories by the two referenced spectra to the inspected data, respectively. The simulation method is gradually developed by adjusting vehicle’s dynamics parameters in terms of a virtual dynamics method to reduce the difference between on-line inspected data and the dynamics simulations. Availability is verified by the method developing process on dynamics simulation of China railway freight car with 23 ton axle weigh.