Applied Mechanics and Materials Vols. 644-650

Abstract: μOS, the operating system of microkernel wireless sensor network, is a real-time multi-tasking operating system; the author designs a semaphore synchronization mechanism and works out mutex semaphore in the paper, in order to avoid errors resulting from resources sharing by multiple tasks in a competitive manner. It is shown from experiments that the mechanism is capable of synchronizing and multi-excluding in μOS more effectively, thus optimizing kernel synchronization and mutex in a simpler and more efficient manner.

Abstract: The rapid development of wind power generator, the service life and efficiency but various fault often will not only shorten the wind generator, also brought the loss of life and property to the people. For fault diagnosis is an effective method of fault diagnosis using the motor vibration signals, This paper adopts the HHT analysis method, the vibration signal of the wind machine for processing fault characteristics are obtained, and the fault diagnosis,improve the efficiency of fault diagnosis, the conclusion shows that it is an effective method of fault diagnosis for fan, troubleshooting and repair of fans have important practical significance.

Abstract: According to design theory of attenuator, combining with the practical situation of microwave moisture contactor, this paper designs the structure of attenuator which center frequency is 10 GHz and the gain is greater than 10dB. Then making simulation and analysis with HFSS, and obtains a group of design parameters that meet the working requirements. Finally, verifying the feasibility of the attenuator by test.

Abstract: For the development of the wind power industry in Inner Mongolia Autonomous Region, focused on the study of WTG3-1500-type wind turbine in the National Grid Tongliao Ku lun qi amount less if Le Soon South Orleans wind farm, we make static finite element analysis and modal analysis of the wind turbine tower. It comes to a conclusion that resonance of the tower models does not occur during normal operation. The overall structure meets the requirements of strength, providing a basis for the design and optimization of the tower .

Abstract: Power IGBT module and its dynamic and static test equipments are widely used. How to calibrate the IGBT module test equipments is in great demand. Based on the investigation of domestic and foreign method for power IGBT module test equipment calibration, the calibration method of the important parameters, pulse current, for this equipment were researched in this passage. the Rogowski coil and the data acquisition unit were used to realize the pulse current amplitude (up to 5000A) calibration. Calibration device for power IGBT module test equipment was setup, calibration specification for power IGBT module test equipment was authorized to ensure the values of power IGBT module test equipment.

Abstract: The technology of face recognition is the media to face images as the identity of the face recognition system.Through the choice of color space and the establishment of skin color model, give a rough detection for the human's image, then use the face Haar features getting more accurate detection.

Abstract: The pre-processing method of blind source separation based on multifactor analysis is proposed to solve the blind source with noise. Firstly, the shortcomings of existing methods of blind source separation are point out after analyzing their principles. The multifactor analysis is introduced in blind source separation and the maximum likelihood estimate based on expectation maximum is used to estimate the common factor and random error. Finally the FastICA algorithm is used to separate BSS result. The validity and the advantage of this method are illustrated by an example.

Abstract: We experimentally report that electromagnetically induced transparency (EIT) in the nonlinear propagation of probe beam, four-wave mixing (FWM) images and in a cascade three-level atomic systems. It is shown that by changing the frequency between pumping fields or dressing fields, respectively, the properties of the measured signals including the intensity and spatial images are affected greatly, including the electromagnetically induced transparency (EIT), Aulter-Townes splitting. By changing the laser frequency we can control the four wave signal, Moreover, the AT splitting effect due to spontaneous emission was also observed under EIT conditions..

Abstract: In order to study the frequency characteristic of body oscillation in the anterior-posterior (AP) direction during upright stance, 10 subjects were exposed to the motion platform with specific posture and followed the tracks of the passive motion stimulus, sinusoidal waveform, with the increasing frequencies (0.05-1.2Hz). By measuring the displacement of the center of gravity (COG), the bode diagram between the motion of platform and body’s COG was obtained. Results showed that the mean cut-off frequency (COF) is 0.5 Hz, the mean resonance frequency (RF) is 0.316 Hz and the bandwidth of the body oscillation is 0.1-0.5 Hz in AP direction. In a conclusion, this study reaches the frequency response of human dynamic balance under passive motion stimulus by using COG values, proposes a method based on the COF values to evaluate the balance ability, and provides data support for the research of balance ability in the medical community.

Abstract: This paper use the topology contravariant to discriminate the intrinsic properties of the pavement crack, structure the metric space of complex data set, make up the topology space, deduce the topology contravariant relation. To distinguish the pavement crack, the data of the crack must be gained. Using the topology contravariant relationship from the original space of the Pavement crack to the target space, the detection to the pavement is more accurate and faster. The theory of this paper has been tested by simulation.