Applied Mechanics and Materials Vols. 241-244

Abstract: A all-fiber perimeter alarm system is designed which is composed of the optical Fiber Sensor Module(FSM) laid along the perimeter and Security Information Control Center(SICC) (including display terminals-the large screen display, the terminal of personnel operation, the system control host, etc.) and optical fiber fence (or sensor board). It uses optical fiber (cable) as the sensing and transmission device, through directly contacting with optical fiber (cable) or through the carrying material, passing various disturbances to the fiber (cable), carrying continuous real-time monitoring and collecting disturbance data. Through the back-end analysis, processing and intelligent identification, it can determine the different types of external disturbances. The system can automatically obtain the real-time alarm information that the optical cable generates and process these warning messages according to predefined business logic, then generate sound and light warning prompt and provide several functions of statistics, query on the warning message.

Abstract: In this few years with the development of the application of the technique about the fiber sensing in several areas with the bad testing environment, it demands the packaging structure of the fiber interferometer, the center device in the fiber sensing system, with the remarkable capability of vibration and sound isolation. However, the performance index of the such product is still far from the requirement. Based on the method of suspension type we first produce the sound isolation device with the two-part vibration isolation structure. Then during a series of tests we find that it has the remarkable capability of vibration and sound isolation, the capability of sound isolation is higher than 40dB in the whole range of the testing frequencies and the well capability of vibration isolation, which reach to as most as 60dB and at least as 20dB, has been shown above 5Hz.

Abstract: This paper designs a new type of the inside and outside tube differential pressure flowmeter based on the traditional flowmeters. Its structure is introduced and its theoretical formula is induced. For the online measurement of wet gas, this paper has done a lot of simulate experiments on the standard experimental platform. Applying origin drawing tools, it has drawn the relationship curves between influence parameters and over-reading specific value. And then, it analyzed the influence of different characteristic parameters. Finally，proceeding from the basis of over-reading theories，it has explained the internal reasons for these phenomenon.

Abstract: Fire proof leakage current circuit protective device is a kind of protect devices. It monitors the leakage current of power supply. When they have some trouble, it shuts down power supply. Beginning from the design, the paper introduces the process of Fire proof leakage current circuit protective device design including software and hardware based on AVR MCU.

Abstract: Automated press line is a kind of very important device in the production of automobiles, and its production quality and efficiency have a direct influence on the production efficiency and quality of automobiles. Automated pressing is the effective measure and major way to increase the productivity and improve the working conditions. Some pressing workshops is taken as examples in this paper to research into the working requirements of radio frequency identification (RFID), the interference in the process of identification, the selection of RFID reader, the selection of label, device purchasing, and the connection with computers, so as to make a comparison between the moulds and manage the moulds.

Abstract: In accordance with the relevant safety standard requirements for electrical equipment, this thesis proposes a residual voltage detection method with high accuracy and low power consumption . The power frequency synchronization signal is obtained by the measuring instrument with the zero-crossing detection circuit used. In the power frequency AC peak moment the measured instrument's power is cut off and the measured equipment's residual voltage is sampled by the input circuit with the high input impedance. Under the control of the NIOSII, the on-line detection of power-down residual voltage of equipment after the 1second and 10seconds is realized with the high speed sampling /hold-circuit and high precision ADC module used. The experimental result shows that the measuring instrument has good stability, with measurement accuracy up to 0.506%, meeting the measurement requirements.

Abstract: An automatic liquid manometer which operates on the basis of a position-detecting system is described. A slanting laser beam is directed to the meniscus of liquid in a glass tube manometer without a float and is reflected by the meniscus. The reflected spotlight is focused on a position-sensitive detector (PSD) through a lens. The application of external pressure to the manometer causes the position of the meniscus to change, and the pressure can be gotten indirectly by this position. The relationship of the output of PSD to the displacement of meniscus was investigated, and the fuzzy control rules were determined to make the meniscus back to its original position fast and stable. The system has been tested with good results.

Abstract: Before using high-precision ADC AD7730 in analog signal sampling system, it’s required to measure the actual resolution if needed. This paper introduces the design of resolution detection system for ADC, which is used to evaluate the resolution performance parameter of ADC. First, a framework of the application system is designed, and specified at the example of 24bit ADC AD7730 application based on the Virtual Instrument Development Environment LabVIEW. Finally, actual resolutions of input channels are given and evaluated.

Abstract: Speech is an important method for human communication. In this paper, we developed a new method for detecting speech signal. Because of the advantage of this speech detecting method, it has great potential application value in many fields. Simultaneously, basing on the good capability of wavelet packet for analyzing time-frequency signal, this paper also developed an algorithm of wavelet packet threshold by using hard threshold and soft threshold for removing noise. Comparing to spectral subtraction and Wiener filter speech enhancement algorithm, the proposed algorithm takes on a better performance on noise removing and speech signal reserving.

Abstract: In order to satisfy the needs of protection functions test for intelligent low voltage electrical apparatus, based on the introduction of features of the flexible test technology, a design of protection functions test system for intelligent low voltage electrical apparatus based on the flexible test technology was proposed in this paper. The test system was made up of the hardware composed of industrial computer, multifunction data acquisition card, three phase current generator, three phase voltage generator, etc, and the software developed by LabVIEW. The design idea and the test flow of the software were also introduced in detail. Finally, the application example shows that the protection functions for intelligent low voltage electrical apparatus constructed based on flexible test technology could carry out a high efficient, automatic, accurate test, which fully reflected the three characteristics of the flexible test technology ——flexibility, adaptability and expandability. Therefore, the test system has great practical value and application prospect.