Applied Mechanics and Materials Vols. 241-244

Abstract: Three-Cornered Hats is a classical method to obtain the frequency stability of one single atomic clock without more stable frequency standards available. In this paper, the measurement data of three hydrogen masers in a ground station is used to analyze the frequency stability of one single atomic clock. The analysis steps and problems in application of this method are introduced. The negative values of the calculated Allan variance of one clock with averaging time larger than 4000s occur. It probably implies that the hypothesis of uncorrelated clocks is not acceptable, which will be analyzed further.

Abstract: Considering testing effort and imperfect debugging in reliability modeling process may further improve the fitting and prediction results of software reliability growth models (SRGMs). For describing the S-shaped varying trend of the testing-effort increasing rate more accurately, this paper first proposes a inflected S-shaped testing effort function (IS-TEF). Then this new TEF is incorporated into the inflected S-shaped NHPP SRGMs for obtaining a new NHPP SRGMs which consider S-shaped TEF (IS-TEFM-IS). Finally the IS-TEFM-IS and several comparison NHPP SRGMs are applied into two real failure data-sets respectively for investigating the fitting power of the IS-TEFM-IS. The experimental results show that the inflected S-shaped NHPP SRGM considering IS-TEF yields the best accurate estimation results than the other comparison SRGMs.

Abstract: To calibrate the helium mass-spectrometer leak detector in-site in the whole range, a series of leaks with helium-permeable membranes of different leakage rates were connected to a helium mass-spectrometer leak detector separately, then a set of readings of standard leaks were gained, and the relation curves were fitted mathematically between the standard leakage rates and leakage readings so as to give a fitting formula between the whole-range readings and leakage rates. As a result, the simplicity and efficiency method make it suitable for calibrations of helium mass-spectrometer leak detector.

Abstract: In order to improve the measurement accuracy of optical detection instruments, temperature control circuits for narrow band-pass filters are given, and the error analysis is applied to temperature control circuits.The principle of a temperature measurement circuit is studied and the method of a driver circuit is described. A variety of influencing factors of temperature control accuracy are discussed. Moreover, for these error factors, improvement measures are given to reduce the nonlinear error. Finally, circuit parameter error is quantified to propose a calculation method for margin of error in a temperature control system.

Abstract: An online safety warning system based on FBG sensing elements was developed to prevent the leakage or explosion of the high temperature and pressure pipeline. On the basis of using optical sensing interrogator, a computer monitoring software has been designed to monitor the surface strain of the high temperature pipeline, and this software was written in LabVIEW，including signal analysis, real-time view, data management and related functions. Combining the software and GSM module, a SMS warning and reversing controlling system has been developed into the remote safety warning system.

Abstract: In order to enhance the reliability of traveling wave fault location (TWFL) systems, an improved wide area traveling wave fault location (WA-TWFL) algorithms is presented in this paper. In the disturbance area that near to the fault position, we can first get the possible fault positions by using the outgoing path data from the substation that first records the initial traveling wave, then use the possible fault position to verify the reasonableness of data recorded. The fault position that has no counter-example in logical is the real fault position. EMTP simulation verifies the validity and applicability of this algorithm.

Abstract: Equipment maintenance support capability is an important part of operational capability and the evaluation of equipment maintenance support capability is very important to the establishment of battle effectiveness. Cloud theory is applied to equipment maintenance support capability evaluation on basis of the establishment of the evaluation index system of equipment support capability. The application steps of cloud barycenter evaluation method to equipment maintenance support capability evaluation are analyzed. The evaluation result is achieved using weighted deflection degree which is used to demonstrate the deflection degree between equipment maintenance support capability and its perfect state. The correctness and validity of the proposed method is verified by the calculating result, which provide an efficient method for equipment maintenance support capability evaluation.

Abstract: A new diagnostic strategy that based on remote video monitoring by image processing is proposed, through the deployment of video capture device in the processing site, it can obtain the image information of CNC machining tools processing status, achieve real-time monitoring and fault diagnosis of CNC machining tools. Take the network engraving machine as the cut-in point, this paper introduces the general structure, system functions and principle of the remote monitoring and diagnostic system. This system can not only achieve self-test of the network engraving machine fault diagnosis, alarm and shutdown feature, reducing the sudden failure rate and improve equipment utilization, but also monitor a number of distribution engraving machine processing status through remote video monitoring, and ultimately realize the function of unattended processing site, remote centralized supervision.

Abstract: Based on the analysis of a 110kV digital substation main transformer differential protection action situation，pointing out that the malfunction cause of the trip， give out the improvement program，improve the understanding of the GPS in the digital，and recognize the the importance of intelligent substation．Provides a theoretical and application for the proper preparation of the same type of protection device，thus effectively avoid the protection device in the series malfunction again．

Abstract: The establishment of electronic equipment and more operating conditions of knowledge acquisition simulation environment, considering the failure of electronic equipment failure caused by the internal laws and mechanisms, to the essence of the phenomenon of electronic failure analysis, combined with the physical prototype test results and raw statistical data, research the actual process of using electronic equipment, considering the state of properties, condition monitoring parameters and the integration of traditional knowledge, expertise and reasoning techniques to be applied to physical prototype of a certain conclusion, not only for the early prediction of potential failures, laid the theoretical foundation for forecasting , and fault prediction system for the electronic equipment, the development provides important data and technical support to solve the electronic equipment maintenance and support tasks needed problem.