Applied Mechanics and Materials Vols. 333-335

Abstract: To prevent environmental pollution and leakage accident, a hypergolic vapor monitoring instrument based on electrochemistry is discussed in this paper. The electrochemical sensor is designed to detect hydrazine compounds of 10^-6 level in real time .The monitoring instrument based on electrochemical sensors shows its advantage of hign specificity and fine stability .

Abstract: Experiment for bare fiber and two kinds of commercial fiber had been done using PPP-BOTDA technology in the paper, and the testing results are analyzed. Experimental results show that different types of fiber have different critical effective sensing length. Despite possessing the 10cm order spatial resolution, if the sensing length of fiber is shorter than the critical value, PPP-BOTDA can not get correct strain. Basing on this experiment result, the concrete crack is simulated and tested. The point fixation bonding method overall bonding method is used in the experiment. The result shows that PPP-BOTDA technology can detect the existence and propagation of crack, and which can even test the width of the crack.

Abstract: The monoglyceride, diglyceride, triglyceride and free fatty acids in vegetable oil was detected by the analysis method of near-infrared spectroscopy. The near-infrared spectrograms of 77 oil samples were collected, including 67 samples for calibration set and 10 samples for prediction set. The Partial Least Squares (PLS) optimized models were established with OPUS chemical analysis software. The results demonstrated that the determination coefficient of monoglyceride, diglyceride, triglyceride and free fatty acids was 0.9691,0.8627,0.8742 and 0.9194, respectively. And the standard error of prediction for the four components was 0.0104, 0.1830.201 and 0.0106, respectively. The presented results showed that the analysis method of near-infrared spectroscopy can be used to identify the diglycerides and triglycerides, but as for monoglyceride and free fatty acids, further experimental verification is needed.

Abstract: A binary phase only pupil mask with phase rings is placed on the plane of the aperture to modulate the wave front of the traditional microscopic imaging system, the modulation transfer function curves, obtained by the annular ring aperture applied to the pupil of the imaging system, do not change much within the required depth of field range, therefore, the loss of systems imaging information is avoided,meanwhile the depth of the field is enlarged. The Zemax simulated result shows that it is able to make the depth of field of microscopic imaging system extend 10 times to adopt this method.

Abstract: Inter-turn fault is the most probably fault in permanent motor. It is important to find the inter-turn fault and protect the permanent motor. Stator windings current is used to evaluate the inter-turn fault. A small resistance is connected with the permanent motor. The stator windings current is transferred to voltage and this signal is send to data acquisition system and transferred to digital signal. LabVIEW is used to control the data acquisition system and receive the digital signal. FFT is used to analyze the frequency character of the stator windings current and find the character of the inter-turn fault. Test shows that the permanent experimental system consisting of computer and LabVIEW can fully meet the requirements of permanent fault test and research.

Abstract: Tag collision is one of the key issues of the RFID system,it increases the energy consumption and slot overheads of passive tags.After giving a brief analysis of the existing anti-collision algorithms,a novel anti-collision algorithm based on the characteristics of a continuous distribution serial number of RFID aquatic shelf life monitoring system was proposed,The algorithm firstly uses the collision information to generate two initial serial number,then identifies all tags via minus 1 and add 1 of the initial tag serial number.Simulation results show that the proposed algorithm has a faster identification speed and less tag transmission bits.

Abstract: A high efficiency, informatization, automation water-level monitoring system was designed. It was very helpful to improve the level of hydrological forecast and the level of geological disasters forecast.This water-level monitoring system was based on a 32 bits LM3S615 embedded microcontroller as the main control unit. It consisted of four modules: the main control unit(LM3S615),the signal acquisiton and conduction module, the power supply module and the wireless transceiver module. In the system, the redundant power supply circuit was designed to improve the system’s reliability further. After the test, the operation of the system has been able to complete the expected target, and achieve the performance requirement. At the same time, it also has the very good instruction function for the development of related industrial products.

Abstract: Ground penetrating radar (GPR) is a real-time, non-destructive testing technique using high frequency radio waves that can yield data with very high spatial resolution and the data can be acquired rapidly. It uses high frequency radio waves to inspect the interior of concrete structures and is widely used for tunnel construction due to its fastness, accuracy, continuity etc.. The paper takes a tunnel as an example, systematically introduced the work principles of GPR and elaborates on the successful application of GPR to quality detection of the tunnel lining. To mainly analyze the quality of tunnel lining such as lining thickness, non compact, cavity, crack etc.. It is important to eliminate the hidden dangers during the tunnel operation, and also give experiences and references for the quality detection of the similar tunnel construction.

Abstract: In this paper, the composition and characteristics of airborne ECM system automatic test system is fully acquainted, the main factors affecting the availability is analysed, the availability evaluation method of fuzzy mathematics system is studied, the corresponding availability evaluation method is proposed and the availability calculation model is established in this paper. Based on the relevant test data and the detail calculation evaluation for the airborne ECM system automatic test system, the automatic test system is verified available.

Abstract: In this paper, the gears fault signal in the engine was studied. Hilbert-Huang transform was applied for the gears fault signal analysis. From the experiment, the normal engine frequency of 240 Hz was got and the gears fault signal frequency concentrated in 2800 Hz. Through the study of intrinsic mode function and the Hilbert spectrum, improper meshing gears were the cause of this problem. The results showed that this method can effectively extract the fault feature and found out the cause of the problem. A new effective method is provided for the gears fault diagnosis.