Advanced Materials Research Vols. 718-720

Abstract: Electric-explosive initiator is one of the important firing units in demolition system, its quality effects the safety and reliability of demolition work greatly. Therefore, when using electric initiator, the electric performance of the individual detonator needs to be tested exactly. At present, the equipments being used to test this character are very simple, and their testing means, process and results no longer meet the needs. By using the technologies of virtual instrument and the digital electronic measurement, a test device was demonstrated, designed and manufactured. The proposed system is different from the existing ones by featuring computer control, convenience in use, high precision of parameters setting, automatic data processing, management and judgment.

Abstract: Database of time series of the instantaneous three-dimensional three-component (3D-3C) velocity vector field, measured by tomographic time-resolved PIV(Tomo-PIV) in a water tunnel, was analyzed to investigate spatial topologies of coherent structures in the turbulent boundary layer (TBL). A new concept of spatial locally averaged velocity structure function of turbulence is put forward to describe the spatial dilation or compression of the multi-scale coherent structures in the TBL. According to the physical mechanism of dilation or compression of multi-scale coherent vortex structures in the turbulent flow, a new conditional sampling method was proposed as well to extract the spatial topological characteristics of physical quantities of coherent structures, such as fluctuating velocities, velocity gradients, velocity strain rates and vorticity during the bursting process in the Tomo-PIV database. Furthermore, the anti-symmetric structures are the typical spatial topologies characteristics for the velocity gradients and vorticity during coherent structures burst.

Abstract: The vibration character is analyzed with the methods of harmonic wavelet and time domain indexes of reconstruction with simulation signal and test data. Using harmonic wavelet compactly supported characteristic and box spectrum, the data is rebuild with some specific frequency wavelet coefficients. This not only realized the frequency domain filtering, the time domain information is also retained. The analysis of time domain indexes shows the method can identify the vibration amplitude growth derived from the noise or from the useful signals. The simulation and experimental results confirm that, with the harmonic wavelet reconstruction signal time domain indexes, the gear fault detection and diagnosis can be achieved under the condition of strong noise.

Abstract: This paper researches DC high voltage ratios measurement method, which based on two-digital meters with external synchronous trigger mode. Through experiment, the measurement method can overcome the effect of high voltage power supply ripple and drift. The type A uncertainty of this method could decrease more than 10-100 times.

Abstract: This paper introduces current situation and development trend of measuring and testing systems and impact on traditional measuring and testing instruments and devices caused by rapid development of embedded technologies represented by high-performance embedded microprocessor and embedded operating system technologies. To combine newly developed high-performance embedded technologies with traditional measuring and testing technologies can greatly improve performance, cost, power consumption and volume indexes of measuring and testing instruments, enabling them to obtain incomparable advantages over traditional instruments.

Abstract: The paper analyzed voltage variation generation mechanism of DC high voltage divider advances high voltage divider variation measurement method---serial and parallel voltage double-method, verifies the establishment condition of series and parallel double-voltage method in theory, measures the voltage variation of DC high voltage divider through experiment, the measurement uncertainty is better than 10^-6.

Abstract: To test and rate automobile braking ability rapidly, correctly with low cost, a road test system of automobile braking ability is constituted in LabVIEW based on MEMS after the deeply analysis of rating principle and national standard of it. Then the real car test is accomplished using this test system and the test result has been analyzed which prove the strategy of system building is feasible and has widespread application value and prospect in engineering.

Abstract: Concrete embedded fiber Bragg grating strain sensors are used to monitor real-time strain of each section in the tunnel surrounding rock supporting structure, and the nonlinear regression analysis method is adopted to analysis the real-time measurement data. By using nonlinear regression analysis method, the strain development status of surrounding rock supporting structure can be grasped timely and the variation trend of the strain value of monitoring point can be predicted, which can provides foundations for judging the stability of tunnel supporting structure.

Abstract: For high production of raw coal in steep coal seams, it is crucial to obtain engineer demands by enhancing section height in horizontal caving. However in-situ operations copious methods like pre-blasting was always needed to broken top-coal which was difficult to excavate commodiously and safely. Explosive wave caused by pre-blasting would destroy stress balance around entries, and definitely result in entry disturbed zone (EDZ) being loosen zone. Aimed to determine boundary of EDZ and keep rock mass in both entries steady, combined tests to EDZ of rock masses of head entry of +600 east-side stope of 43# coal seam was done in Wudong Colliery as research background with ground penetrating radar (GPR) and mono-hole ultrasonic wave experiment. It indicated that scope of EDZ here was 2.2-2.3m, which would be prerequisite to optimize supporting scheme in field.

Abstract: The film thickness is an important technical indicator of film devices, and its accuracy directly affects various performances of optical components. In fabrication process of film device, fast and accurate measurement of film thickness has positive significance on product quality control. In this paper, measure film thickness with lateral shearing interferometry. Collect interferograms through structured lateral shearing interference platform, process interferogram with Fast Fourier Transform method to extract phase, unwrap the wrapped phase to achieve phase value. Finally, calculate film thickness based on lateral shearing interference principle. The thickness of sample is 119.6800nm measured by this method, basically the same with the result 120.6036nm that measured by ZYGO interferometer. This experiment shows that lateral shearing interferometry not only suit to measurement of film thickness, but also abundant high-precision method of measuring film thickness, and has high practical value.