Applied Mechanics and Materials Vols. 220-223

Abstract: This paper presents a portable miniaturized integration UV-VIS absorbance detection system for the microchip electrophoresis (MCE). The TOCON_nano high sensitive SiC pre-amplified UV Sensor (Sglux GmbH, Ostendstrasse, Berlin, Germany) is used to measure extremely low UV radiation intensities in the nanowatt scale. This detection system volume is 280 ×200×150 mm³, the weight is less than 2Kg. The PMMA was used as the MCE substrate materials. And the electrophoresis microchannels are fabricated with the CNC milling, have the cross section area of 150μm ×150μm. With this detection system, the detection limit for the Cl- electrophoresis can reach 10^-10mol at the indirect UV-VIS detection mode. Two ino^{Superscript text}rganic ions Cl^- and SO₄^2- could reach the baseline separation in 3 min.

Abstract: A localization algorithm from connectivity based on distributed weighted-multidimensional scaling (cdwMDS) algorithm is proposed in this paper. Each sensor selects a neighbor sensor adaptively, calculates the iteration step size with the average connectivity and updates the estimate location by optimizing the local cost function. Connectivity is used to determine the step size of gradient iterative optimization in this algorithm. After getting the estimated positions, a relative map is built and the absolute coordinates can be obtained. Simulation results show that this method could achieve higher localization accuracy and more stable convergence.

Abstract: This research based on a new type of Double-cone flow sensor, using computational fluid dynamics (CFD) method and orthogonal experiment to investigate the influence of key geometric factors, such as fore-and-aft cone angle, equivalent diameter ratio and channel flow length, on discharge coefficient, discharge coefficient linearity and relative pressure loss of double-cone flow sensor, and finally predict the best optimal match of these geometric factors. The turbulence model is RNG and the medium for simulation is water. After the simulation, a special device for calibration was set up to verify the computational conclusion. The results show that the biggest deviation of simulation on discharge coefficient linearity and relative pressure loss are less than 0.4% and 1.2%, the results simulated by CFD are in good agreement with that by experiment.

Abstract: In this paper, based on the wavelet transform method, the multi-sensor data fusion technology is adopted to solve some key problems in pipeline leak detection system. Compared with the traditional filtering method, the wavelet transform method can better remove the pipeline leakage signal noise. When the corresponding wavelet is selected, after FPGA realized, the method has the advantages of fast speed, arbitrarily data width set, which can better meet the needs of real-time signal processing requirements of pipeline leak. At the same time, VHDL language has the characteristics of portability, greater generality. When multi-sensor fusion technology is used in the paper, the relation, correlation, estimation and integrated processing is done in turn to the information from multiple data sources, the system can achieve better detection performance than a system using the single sensor, so as to form a more complete, reliable pipeline real time detecting conclusion.

Abstract: This paper investigated an novel wireless RF pressure sensor fabricated with SU-8 polymer. The sensor consists of an inductor (L) interconnected with pressure-variable capacitor (C) to form a LC resonant circuit. The fabricated devices is 4 × 3 mm² in size and houses 9 turns of Cu electro-plated coil with inductance of 100 nH. In this system, RF signal was transmitted from external antenna to the fabricated LC resonator. Then RF signal was changed as power of fabricated device via inductive coupling. The external antenna was modulated by resonant frequency of the LC resonator. By detecting this abrupt resonant frequency shift of the device, the pressure change of the device can be measured by wireless method.

Abstract: The electron in the RTD has a high mobility with the resonant tunneling effect. We have embedded the RTD in the structure of MEMS sensor using the meso-piezoresistive effect. The sensitivity of sensors is higher one order of magnitude than the accelerometer which used the silicon piezoresistive strip as sensitive unit. In this paper, we optimize the temperature effect of RTD as the sensitive unit of sensors by reducing the size of emitter mesa of RTD structure. In the experiment, the temperature coefficient reduces from 10μA/°C to 5.22μA/°C at the peak, and reduces from 35μA/°C to 13.88μA/°C at the valley. Meanwhile, the temperature effect of bias voltage sensitivity reduces from 6mA/°C to 2mA/°C at the valley. Finally, the reliability and precision of RTD structure used as the sensitive unit of MEMS sensors is improved.

Abstract: The main factors affecting the temperature drift of the fiber optic gyroscope was analyzed in this paper. The autoregressive model of temperature drift related to the temperature and the rate of temperature change was built. The coefficients of the model can be obtained by least squares fitting. Experiments show that the model was effective. With the drift model the drift trend caused by temperature can be estimated. The temperature drift can be compensated using the drift trend. The experiment result shows that the drift error can be decreased about 87% after compensation.

Abstract: An attitude determination system has been designed for the geocentric pointing triaxial stabilized satellites which employ a continuously running inertial rate sensor in conjunction with sun sensor and earth sensor. Earth/sun sensor data are processed to generate corrections to satellite attitude, gyro constant drift and earth sensor drift bias estimates. An extended Kalman filter based on the attitude determination system is derived in this paper for the satellite using two earth sensors, a two-axis digit sun sensor as attitude sensors and a three-axis gyro for the angular velocity. A simulation model is developed to estimate the attitude determination performance. Simulation results show that precision attitude determination is achieved using the selected attitude hardware and algorithms.

Abstract: For the multisensor multichannel ARMA signal with ARMA colored measurement noises and unknown model parameters and noise variances, this paper presents a kind of multi-stage identification method. At the first stage, the on-line information fusion estimator for the unknown model parameters is presented based on the Recursive Instrumental Variable (RIV) algorithm and the Recursive Extended Least Squares (RELS) algorithm, which is realized by computing the average of local estimators for model parameter. At the second stage, the on-line information fusion estimator for the unknown variances is obtained using the correlation method, which is realized by computing the average of the local estimators for noise variances. At the third stage, the information fusion parameter estimator of MA model is presented using the correlation method and the dead zone Gevers-Wouters and LS algorithms.

Abstract: Different types of disasters occur frequently in coal mines. This paper analyzed the characteristics of different disasters, chosen the corresponding sensors to collect the information of disaster scene, and discussed the methods of multi sensor information fusion. Lastly, the multi-sensor information fusion strategies for fire, gas outburst, flood, and roof collapse were proposed in this research.