Advanced Materials Research Vol. 1083

Abstract: Cross sectional area of single filaments, a key parameter to characterize fiber properties, was experimentally studied using a desktop scanning electron microscope. Three different methods are employed based on the pixel area, averaged diameter and single diameter measurements, respectively. Results have shown that all three methods can achieve accurate measurement results once the axis of fiber sample is kept parallel to the electron beam. Significant errors are generated for the fiber samples with their axis tilted, which may frequently occur as a sample prepared. For circular fibers, a single diameter measured from tilted fibers is sufficient to determine their cross sectional area at high precision with COV values below 1.6%. By selecting an appropriate method, a desktop SEM can serve as a convenient and powerful tool for accurate determination of cross sectional area as well as morphological observation.

Abstract: FBG (Fiber Bragg Grating) is a new type of optical passive device which can be used in sensing field. This paper demonstrates the feasibility and effectiveness of FBG as the new method of strain measurement, and improves the measuring precision. Based on the strain sensing property of FBG, the study adopts the differential method of double FBGs to make temperature compensation, and conduct the contrast experiment with resistance strain chip. The experimental results show that strain measurement based on FBG agrees well with theoretical calculation. The measurement error: no more than 1%, linear fitting correlation coefficient: almost 1, linearity: 0.17%, sensitivity: 7.92, hysteresis error: 0.347%, repeatability error: 0.333%. The results show FBG’s performance are superior to resistance strain chip, especially in aspect of measuring precision. Therefore, we can conclude that FBG is a feasible and effective method of strain measurement.

Abstract: The temperature and magnetic field data acquisition system is developed for HTS Magnet of ITER. According to its working environment, the type of probes used for detection and the corresponding supporting equipment are chosen. Based on the requirements of data acquisition precision, the selection of the data acquisition instruments is completed. Optimize the number and configuration of probes and keep key monitoring on its Conduction-cooled structure. A complete set of complete data collection and human-computer interaction system is designed by using LabVIEW.

Abstract: This paper deals with the use of probabilistic methods in the reliability assessment of water vapor condensation on the building structures surface. To calculate the resulting probability of failure it was used original and newly developed Direct Optimized Probabilistic Calculation – DOProC method, which has been successfully applied in the software system ProbCalc. To solve this probabilistic computation tasks, this would appear to be very effective and accurate. When calculating the resulting probability of failure there was also taken into account the statistical dependence of the random input variables, which were expressed probabilistically based on long-term monitoring of the assessed building.

Abstract: We developed a fiber-optic beta/gamma imaging detector that can obtain the scintillating images for beta-or gamma-ray emitted from the radioisotope. To evaluate spatial resolution of proposed imaging detector, we obtained the optical images using USAF 1951 resolution target. And then, a modulation transfer function curve of the optical image was calculated. Also, we measured the scintillating images of Tl-204 and Cs-137 with information respecting the beta-and gamma-rays distribution. Finally, the intensities of scintillating light as a function of radioactivity were analyzed from the region of interest in the scintillating image.

Abstract: In order to improve the robustness performance of SURF descriptor applied to stereo image matching, a new matching method is proposed. By using the ratio of minimum to second min Euclidean distance of corresponding features, we can get the coarse matching points aggregation. Then, the epipolar line is computed from calibration parameters. Correspondences are taken as correct correspondences, only if they fall into a small neighborhood of their epipolar line. Taken errors into account, the neighborhood is set (-3, 3). Using this restriction, we can get the correct matching points aggregation. The experimental results show that the correct matches and matching efficiency are better than RANSAC.

Abstract: The feature of deception jamming for GNSS-dot networks is researched and analyzed, and it is difficult to accurately locate and correct the interference position by using the interference detection methods of the traditional WSN, a new attack detection algorithm that based on an improved angle of arrival (AOA) positioning mechanism to determine the point of disruption and interference correction is proposed. Nextly the algorithm of a single interference source localization based on the hyperbolic method by using anti-jamming principle of the GNSS is researched and given, and can locate both single and multiple interference sources. Then the indicators and methods of performance evaluation for the GNSS-dot networks are proposed. Finally, Experiment based on the algorithm is realized, and the attack detection and correction is very efficient, and interference location under ideal conditions is higher efficiency, and the strategies of anti deception jamming are also identified.

Abstract: This paper presents a new model based on assembly line to accelerate the speed of data collection. Traditional data collecting and state monitoring technology requires a CPU which is simple but results time consuming. Assembly line models make the data collection and monitoring process simultaneously and hence improve the efficiency. This paper compares several processing hierarchy and at the end propose a feasible model structure.

Abstract: Considering the characteristics of light-weight and small-size liquid-filled pipes, the method of utilizing the fiber Bragg grating (FBG) sensor to explore the natural frequency of the pipe has been proposed. Meanwhile the natural frequencies of the tested pipe were obtained through the theoretical calculation and simulation analysis. The calculation results show that the mathematical model and computing method are reliable to calculate the natural frequencies of the tested pipe. The experiments show that the measurement results of the FBG sensor are closer to theoretical calculation results. Because of added mass of the sensor, the natural frequencies of the tested pipe are lowered by the accelerometer. However, the measurement results of the FBG sensor can better reflect the actual characteristics with a negligible mass. The FBG sensor can be applied to frequency measurement, especially to those structures affected by added mass of the sensor.

Abstract: Peak reflectivity is a key reflected index of FBG, and it has great effects on the FBG application characteristic in sensing and communication fields. Theoretical and simulation methods are applied to study the cross influence of multiple parameters, such as grating length, grating pitch, and refractive index modulation depth, on FBG peak reflectivity. Research results can provide system recommendations for adopting proper parameter combinations according to practical manufacturing condition and actual demands.