Advanced Materials Research Vols. 718-720

Abstract: Pseudo-range differential is an important differential method, but the pseudo-range differential precision becomes decreased with the increase of distance between users and the reference stations. A new pseudo-range differential method is proposed, that is wide-area-weighted pseudo-range differential method. Six pseudo-range differential reference stations are built in China region, the user choose pseudo-range correction data of the reference stations near the user which use the weighted data as its pseudo-range correction, which can achieve high precision pseudo-range differential in wide area. Selection method of the right and reference station is researched, the method is verified by simulation test, the weighted data method of six, five, four and three reference stations for ephemeris and ionospheric error correction condition is analyzed, and simulation results show that: using the weighted pseudo-range observation error of the three stations nearest the users has the best correction effect among them, in the whole China region, which can achieve precision superior to 0.5m about pseudo-range differential.

Abstract: The special nature of space launch test projects requires ground personnel to reduce the occurring probability of risk and ensure the success of the projects to the greatest extents. Hence how to accurately identify, measure, control and manage risk through effective measurement is currently a focus of risk management for space launch test projects. This paper identifies risk factors in all the stages of the space launch test projects, and analyzes and sorts them based on the gray relational degree. The results offer advices for ground personnel to make more precisely identification and control of risk.

Abstract: Piezoelectric ceramics sheets are used to excite and receive ultrasonic guided waves in a steel bar. The multi-modes and disperse characteristics of guided waves within that are investigated theoretically and experimentally. The results show that ultrasonic guided waves can be generated and received by piezoelectric ceramics sheets which can be used to measure the length of the steel bar and detect the defection in it.

Abstract: This paper presents the design and implementation of a tunable optical delay system, capable of calibrating the optical signal delay by optical measuring instruments. It is also able to measure the delay by optical communication systems, the laser linewidth, the maximum radius of passive optical networks (PONs) and so on. Structure and implementation method are detailed and results show that it is able to measure the optical signal delay within an error of only +/-0.33ns.

Abstract: Tension of mooring chain is the principle characteristic for mooring system. Tensile value which derived from on-site mooring lines could be used for risk assessment, design evaluation etc. It is hard to obtain underwater tension of mooring chain by traditional method, such as strain gauge, FBG, etc. A new tensile measure method is present based on finite element analysis and shape characteristics of stud-less mooring chain. At first, deformation of stud-less mooring chains is analyzed by finite element method and Ansys software. Then, a design of tension-meter is developed on the basis of the deformation characteristic due to the above FEM analysis. Finally, a model calibrate is designed and tested to prove feasibility of present measurement method.

Abstract: Based on the literature review and baseline survey, this study was carried out to explore the structure of undergraduates employability under the background of China. 612 students as the subjects were predicted, the items were formed through exploratory factor analysis. The results indicated that undergraduates employability comprised two longitudinal dimensionalities: job-attain and job-maintain; and the horizontal dimension were two stage structure with 3 second-order factors and 7 one-order factors. Then 412 students were investigated to test the validity and reliability of the undergraduates employability cognition scale. The scale was found to have a good internal reliability coefficient (a=.928) and Spearman-Brown coefficient (r=.852) of job-attain dimension, the job-maintain dimension were .927 and .845 respectively.

Abstract: The digital energy metering system applied in the smart substation are quite different from the traditional meter system, so its nessary to do some research on the digital metering system. With comparing the digital metering systems to traditional metering system, the application structure and characteristics of digital metering system is discussed, the traceability model of the digital electrical energy meter based on IEC 61850 protocol is also given.In the next part,we designed the verification system for digital energy meter, besides the standard digital power source in the test device, calibration device and the general controller are expounded. The performance of the verification system designed in this article shows that the method could be an effective solution to the verification and traceability of digital energy meter.

Abstract: For the first time in Sri Lanka, an attempt was made to measure the outdoor radon levels using CR 39 type passive radon detectors. Preliminary results indicate that in Sri Lanka, ²²⁰Rn isotope is more abundance than ²²²Rn isotope. These results were also confirmed by in-situ measurements. Sri Lanka has one of the highest ²²⁰Rn values in the region. It was also noted that environmental conditions and other physical factors have a significant effect on the outdoor radon measurements using passive discriminative detectors.

Abstract: This paper mainly describes application of non-contact laser thickness gauge in steel plate rolling process, including workstation site thickness measurement, data collection, information analysis and integration with ERP system, as well as problems may arise during applications and sustainable development in the future. Through the system development to realize traditional steel plate rolling industry information planning, paperless operations, increase work efficiency, enhance product quality and zero defective products. Integrated design of steel plate thickness measurement and tachometer, to understand the pros and cons of output products right after steel plate rolling, and do product level classification immediately to assist enterprises to save manpower, time and loss cost of export defective products to the market, and eventually increase products competition and profits.

Abstract: Lock-in amplifier is widely used to detect weak signals from significant background noise. In this paper, an FPGA-based Lock-in amplifier is implemented on the DSP Builder platform to measure impedance between biological cells and electrodes. To improve the measuring accuracy, a narrow band low pass filter with low cut off frequency was implemented. This low pass filter consists of a five-stage cascaded integrator-comb filter, two half band filters and a FIR low pass filter. Simulation shows that with a system clock of 10MHz, the cut off frequency of the low pass filter is lower than 20Hz. Experiments demonstrate that the implemented lock-in amplifier is able to detect weak signal with strong noise, making it an attractive approach to implement lock-in amplifiers which is more flexible and can meet the needs for specified measurements.