Advanced Materials Research Vols. 989-994

Abstract: Considering the problem of the energy consumption in the gas fractionation unit, PROII process simulation software is used to calculate the gas fractionation unit and to analyze the effect of process parameters. On the premise of ensuring product quality, these parameters can reduce energy consumption, improve economic benefit.

Abstract: The airborne omni-directional antenna must not only satisfy the indicators of omni-directional horizontal requirements, but also have conformal shape with the surface of airplane. The common monopole antenna and microstrip antenna can not meet the above requirements. Under the background of the airborne antenna miniaturization and conformal demand, this article designs a kind of airborne circular slot antenna. The structure of the antenna is simple, which meets pattern VSWR < 1.4 bandwidth of 350 MHz to 376 MHz and meets pattern VSWR < 2 bandwidth of 338 MHz to 438 MHz .Its maximum gain within the operating frequency range can be 4.205 dB .

Abstract: distribution network line usually adopt neutral point grounding way of three-phase three-wire power supply, improve the power supply reliability, reduce the line loss, increase the margin level of the distribution line, reduce the rate of tripping. But using three-phase three-wire power supply line in the actual operation of distribution network, the single-phase earth fault happens often, seriously affected the substation equipment and the safe and economic operation of the distribution network. Based on such fault is analyzed, and puts forward new on feeder terminal for such fault detection scheme.

Abstract: In this paper, a predicting model of silicon content in blast furnace hot metal is built based on artificial neural network and genetic algorithm, which optimizes the initialization weight values of neural network with genetic algorithm. This model can effectively improve the prediction accuracy and reduce the calculating time. Online application shows that the predicting model can effectively predict the silicon content in blast furnace hot metal and play an important role in production. when required absolute error was within ±0.03, the accuracy of model can reach 81.4%, and when absolute error was within ±0.04, the accuracy can reach 91.4%.

Abstract: Thermal conductivity of aluminum nitride (AlN) has been calculated by density functional perturbation theory (DFPT) and quasi-harmonic approximation (QHA) combined with Debye theory in the paper. Debye temperature is evaluated respectively from sound velocity and heat capacity. From 300K up to 1000K, the predicted thermal properties in pure crystal AlN based on these two Debye temperatures are compared with each other and the latter shows excellent agreement with Slack’s experimental data. The relative difference based on Debye temperature from heat capacity is within the limits of ±5.5%. This agreement with experiment is due to the Debye temperature derived from capacity contains the temperature effect while describe the three phonon process.

Abstract: It is very meaningful to predict the temperature and thawing time during the thawing process of frozen food in production and life, this paper proposes a physical model of cylindrical frozen food during the thawing process, combine the finite difference method with element balance method to solve the thawing time and the temperature at regional center R/2 and boundary nodes. Take the beef as an example for the experimental verification. Through numerical calculation and experimental verification, the maximum error between the theory thawing time and experiment is 8.4%. The results show that: it is highly consistent with the experimental results that using numerical method to predict the thawing time and temperature change curve, at the same time, the temperature maximum error in center area is 1.2°C, the temperature maximum error of R/2 is 0.8°C, the temperature maximum error of the boundary node is 1.5°C, so the numerical simulation in studying thawing of freezing food is fairly reliable.

Abstract: In this paper, we present a modified discrete Fourier transform (DFT)-based channel estimation method. The conventional DFT-based method will produce additional high frequency component in the channel impulse response, and degrade the accuracy of channel estimation. The modified algorithm can eliminate additional high frequency components by extending the LS estimate in frequency domain with a symmetric signal of its own, and selects the useful paths by calculating the changing rate of energy. Thus, the proposed algorithm become more accurate. The simulation results show the new algorithm can reduce the influence of noise on channel estimation efficiently, and the performance of the improved method is better than the LS and conventional DFT algorithm.

Abstract: This paper investigated the bearings-only tracking approach based on dual station detection. In order to solve the problem of strong nonlinearity in bearings –only measurement system, we introduced the unscented filter which is based on the idea of unscented transformation. Compared with traditional extended Kalman filter, unscented filter has shown better convergence and stabiltiy, especially in stabiltiy of tracking waveform. Matlab simulation scenario is taken for illustrating the effectiveness and validity of the unscented filtering algorithm.

Abstract: The microprocessor generates many digital noises that find their way back from the clock reference input of the microprocessor to the reference clock lines with which the RF circuits are sharing. These digital noises are conductively coupled to the RF circuits, including any RF transceiver, Bluetooth module and other RF circuits, such as a local oscillator and phase locked loop circuits, to cause spurious signals and jitters in the circuits, which in turn, degrade the RF performance or cause a radio to fail certain specifications.

Abstract: On the basis of establishing direct geo-positioning model for three-line array sensor ADS40/80 images, in order to optimize the positioning accuracy, the self-calibration technology was used to update the ADS40/80 sensor imaging parameters. Moreover, the ADS40/80 camera error model and self-calibration bundle adjustment model were set up. Multi-groups of ADS40 data over the Songshan experimental field were used for direct geo-positioning and parameter updating experiments. Experimental results proved that the self-calibration adjustment technique can effectively update sensor imaging parameters and significantly improve image direct positioning accuracy.