Applied Mechanics and Materials Vols. 130-134

Abstract: A capillary electrophoresis (CE) method for the separation of four kinds of enantiomers of non-natural carboxylic amino acid was built while hydroxypropyl-β-cyclodextrin (HP-β-CD) derivations as chiral selective material. Several different β-CD derivatives were tested for the chiral separation of non-natural carboxylic amino acid, and it was proved that HP-β-CD could show better chiral selectivity. The separation of enantiomers of amino acid was obtained by CE in a 50-μm i.d.×60 cm (effective length 45 cm) fused-silica capillary at 18 kV voltage, while 10 mM phosphate acted as running buffer and HP-β-CD served as selective material. The detective wavelength was set at 254 nm.

Abstract: The main disadvantage of Land surface temperature (LST) retrieval methods from Landsat TM thermal channel images is that atmospheric profile parameters are needed, and MODIS has several near infrared bands that can be used to estimate atmospheric profile parameters. Two methods that could be used to retrieve the LST from Landsat TM and MODIS data were compared in this paper, the first of them is the mono-window algorithm developed by Qin et al. and the second is the single-channel algorithm developed by Jimenez-Munoz and Sobrino. Atmospheric profile parameters such as atmospheric moisture content, atmospheric transmittance and average atmospheric temperature have been estimated from MODIS data, and the land surface emissivity values have been estimated from a methodology based on spectral mixture analysis. Finally, a comparison between the LST measured in situ and retrieved by the algorithms over urban area of Changsha city in China is present. Result indicates that the two LST retrieval algorithms can get high-precision results in support of atmospheric parameters from MODIS images, the average deviation of mono-window algorithm is 0.76K, and the deviation of generalized single-channel algorithm is 1.23k.

Abstract: The design of multi-channel temperature acquisition system based on MSP430 and temperature sensor DS18B20 is presented in this paper. The simulation can be realized by using Proteus. The system has the following advantages: the structure of system is specific; the circuit is simple and it’s easy to control. The system can complete the acquisition and display of multi-channel temperature, it also has other functions such as transferring data to PC, etc. The simulation shows that the system is low cost, high reliability and high practical value.

Abstract: In recent years, infrared temperature-measuring attracted more and more attention from home and abroad. Infrared temperature-measuring is non-contact and does not destroy the temperature distribution of the measured target object. At present, infrared radiation thermometer (point thermometer) and thermal infrared imager are wildly used. They both have advantages and disadvantages. The array type infrared radiation thermometer discussed in this paper contains the advantages of IR thermometer and thermal infrared imager and could measure the multi-point of the target’s surface simultaneously and accurately. Its basic principle is to obtain array processing to the infrared detector, simultaneously measure the multi-point temperature of the objects, take the measured object as a benchmark to calibrate infrared radiation thermometer so as to solve the problem of radiation rate fixed difficulties and improve accuracy of radiation temperature measurement.

Abstract: In view of the structure and characteristics of the vehicle dynamic weighing system, this paper uses the sensor data fusion technology to detect the non-target parameters which impact the feature of pressure sensor, such as operating temperature, the speed of vehicles and so on. In addition, we can reduce the cross-sensitivity of these non-target parameters through applying the fusion algorithm. Finally, through the experiments this paper verified the effectiveness of this fusion algorithm and improved the detection accuracy of the dynamic weighing system in some degree.

Abstract: A set of data acquisition terminal for automotive sensor three voltage level signal performance testing is designed. It is connected together to form a complete set of automotive sensor performance test monitoring system using NI-6259 data acquisition card and PC data collection terminal. The system can display real-time maximum, minimum and average of high voltage level, middle and low, duty cycle, frequency, and flipping or not. The measured signal frequency range is 1Hz~2.5 KHz. The measured data and the specified range of data interface is contrasted, automatically determined whether it is reasonable, and classified saved.

Abstract: The components structure and principle of ring ball gratings sensor is put forward for the present state that there still has not a better method to detect torque under the extreme environment in domestic. According to the localization property in time and frequency domains and the translation invariant property, the preprocessed signal of sensor is decomposed with multi resolution, and the signal is reconstructed with wavelet under the intervention of neural network. The wavelet neural networks (WNN) model is constructed and the algorithm routine is realized in laboratory virtual instrument engineering workbench (LabVIEW). With the testing device, the demodulation experiments are carried out for the corresponding sensor signals when the shaft is continuous rotated along the same direction, rotated along the alternate direction and knocked. The results indicate that the demodulation effect and confidence level are very well.

Abstract: An airborne technology is proposed to detect in flight over natural gas pipeline with a high spatial resolution the presence of trace of methane on the ground. The principle and the architecture of the airborne laser remote sensing system are presented. Field test experiments are carried out on West-East Natural Gas Pipeline of China, and the results show that airborne detection method is suitable for detecting gas leak of pipeline on plain, desert, hills but unfit for the area with large altitude diversification.

Abstract: In order to improve its precision in dynamic environment, a Kalman filter was designed. Firstly, two sets of random drift data of MEMS gyro were respectively analysed, and it was found that the variance of random drift under random vibration significantly increased and its mean also changed. Then calculation results show that attitude angle error under random vibration is 2.6°, while in the static test it is 0.25°. Analysis on the characteristics of random drift was carried out, and it is found that it can be treated as stable, normally distributed random signal. Finally, a corresponding Kalman filter was designed. The results indicated that after filtering the variance of random drift is reduced to 0.0282, 26.4% of pre-filtering and the attitude angle error is reduced to 1.5°, 57.7% of pre-filtering. The above method can effectively compensate for the attitude angle error of MEMS gyro caused by random vibration. This study can be a reference to the application of low-cost MEMS gyro in aircraft navigation.

Abstract: Based on the coupling of laser beam and double arcs, a novel process was investigated. This research set up the laser-double wire pulsed MIG hybrid welding system. Meanwhile the current and voltage sensors were used to detect welding current and arc voltage wave-form and high-speed videography system was used to observe the metal transfer process and arc behavior. The three signals were acquired synchronously. The results showed that the synergic action of the three different heat sources leads to a change in metal transfer mode. It was revealed that the metal transfer mode was two droplets per pulse in laser-double wire hybrid welding process while one droplet per pulse in double wire welding process with the same certain experiment parameters. And we also discovered that the arcs were attracted strongly by the laser beam.