Advanced Materials Research Vols. 718-720

Abstract: By analyzing a series of LANDSAT satellite remote sensing imageries, the coastal dynamics and morphology evolution features of Shuidong Bay, China were studied. The results showed that the maximum surface suspended sediment concentration (SSC) could exceed 0.1kg/m³ in the interior bay. Within the 5m depth contour, the SSC values range from 0.01kg/m³ to 0.06kg/m³. From the 10m depth contour to the offshore, SSC values are less than 0.01kg/m³. The tidal currents have little contribution to the SSC, and the SSC variation is not significant between seasons. This feature shows that the coastal dynamics is weak, and the sediment transport is not active. Generally, the natural shoreline is relatively stable for coastal areas. However, under the impact of aquaculture reclamations in the bay, in over 30 years the total area of Shuidong Bay decreases by 12.8km².

Abstract: Based on a series of multi-source satellite remote sensing imageries and wind parameters extracted from QuickSCAT satellite datasets, the surface suspended sediment concentrations (SSC) of the Zhuanghe coastal area, China was investigated using the retrieval technique. The results showed that the SSC of the Zhuanghe coastal area is higher in the nearshore zone, and gradually diminishes to the offshore. During the ebbing process, the range of high SSC zone is wider than that during the flooding process. This feature indicated that the suspended sediment transport is mainly determined by the ebb currents, and the sediment source comes from the nearshore shallow flats, where the sediments could be entrained by the wind waves and then diffuses offshore or alongshore with the tidal currents.

Abstract: Reservoir microfacies is an important factor affecting the reservoir heterogeneity, and it is significant to accurately predict reservoir microfacies distribution in order to improve oil and gas recovery. The stochastic reservoir modeling method has a strong geological suitability. The reasonable choice of the stochastic modeling method can effectively improve the accuracy of modeling. During the sedimentary facies modeling, sequence indicator simulation is used to characterize the spatial distribution of different microfacies with different variogram,to reproduce the complex microfacies spatial distribution.

Abstract: Detection of moving objects is one of the primary factors to influence the examination surveillance system. A new moving objects detection algorithm based on background subtraction is presented after the introduction various of existing methods. Dynamic threshold conception is put forward while defining threshold. Practices show that this method can successfully overcome lighting variations and the system stability is improved.

Abstract: Wide swath SAR (WSM) has some characters such as wider swath and short interval so that it can be applied widely to monitor deformation, especially it has largo foreground for monitoring slowness deformation.Depessing baseline and DEM error is a key choke point for ScanSAR interferometry.In this paper, ScanSAR imaging principle and error elements are analyzed, in allusion to wide swath SAR interferogram of bam earthquake, influence magnitude of SRTM3 and GDEM for ScanSAR interferometry is compared each other.,at the same time, results of ScanSAR interferometry which use Envisat orbit data ofthree different kinds are studied, in the end ,some referenced and important conclusions are gained.

Abstract: A magnetic-controlled detection system, with a rectangular solenoid coil in a waveguide test fixture, is proposed for radar absorbing coatings. By applying Ku-band rectangular waveguide, the field patterns at different positions, the reflection coefficient S₁₁ and its variation of several coating samples are simulated and measured under current loaded from 0 to 1.0 A. The results show that this detection system is repeatable and stable, and also reliable with the error of less than 10%.

Abstract: This work is dedicated to the development of an on-line monitoring system of SF6 decomposition in electrical devices (SF₆DcpMS) in order to evaluate the health condition of the devices in real time. The feature decomposition, SO₂, and SF₆ purity are continuously monitored. Considering the oxidation-reduction reactions of SO₂ electrochemical sensor during detection, the methodology of utilizing the air in the electrical device is proposed based on the tests of serving devices. And it is proved via tests that electrochemical sensors can be applied into SF₆DcpMS. Besides, infrared detector is employed to detect SF₆ purity. Sampling method of SF₆ in electrical devices is described. There are three keys in the sampling device design for the on-line monitoring system: -- Sensor working environment: The rating pressure is one atmospheric pressure for sensor working. Therefore, a gas chamber is constructed, in which the suitable environment for sensor is completed via a pressure regulator and a pressure sensor. At the same time, an appropriate control method is scheduled. Gas in the chamber is continuously replaced with that in the electrical device to ensure detection accuracy within an acceptable range. -- SO₂ adsorption feature: The monitoring accuracy is seriously influenced by the adsorption feature of SO₂. As we known, flowing gas can decrease SO₂ adsorption feature. So, a micro bump is designed in the gas chamber, which can ensure the gas flowing at the speed of 200ml/min. -- Sample gas back into electrical devices: In order to avoid the gas cause harm to humans, the gas leakage is not allowed in the on-line monitoring system, and the sample gas must be sent back to the electrical device after detection is accomplished. Sample gas back into electrical devices is realized via a bump and a check valve with adjustable cracking pressure. The first SF₆DcpMS in China has been successfully put into service in Zunyi substation, and its performance has been proved out.

Abstract: Aiming at backward current situation of testing technology and fault diagnosis technology of wind power generation in China, a fault diagnosis method based on based on noise detection is put forward. Studied IEC 61400-11 noise measurement technology standard, this paper elaborates the noise detecting method, analyzes the feasibility and diagnostic steps of fault diagnosis, proposes fault signal extracting method based on wavelet analysis. According to analysis and simulation, it is shown that noise measurement is earlier than vibration detection, and the fault signal can be extracted effectively, so it has important value for engineering application.

Abstract: In this investigation, a measurement system based on machine vision applied for auto-hubs eccentricity between the center hole and the pitch circle of bolt holes was proposed. The measurement system was integrated by a CCD camera with a telecentric lens, a diffuse bright-field back light illumination system, a rotating platform, a rotating encoder and an industrial computer. The camera was fixed at a suitable location from the rotation center, which ensured that one bolt hole and a part of the center hole could appear in its visual field. All bolt holes were shot when the auto-hub was rotating, while a rotary encoder recorded these angles. Then a global image of the auto-hub could be tiled by these pictures. An image-processing algorithm integrating morphology, circle fitting, affine transformation and edge extracting was used to measure the auto-hubs eccentricity. According to the measurement of a standard block that had 50um-eccentricity and was manufactured by WEDM-LS (Wire Cut Electrical Discharge Machining-Low Speed), the maximum deviation between measuring value and real value was less than 0.013mm, eccentricitys standard deviation was 0.0035mm and the standard deviation of eccentricitys direction angle was 2.37°. Meanwhile the experimental data of real auto-hubs gave an eccentricitys standard deviation less than 0.013mm and a direction angles standard deviation less than 2.1°.

Abstract: A novel digital holographic interferometry used for measuring the 3D shape is proposed. The theory analysis and simulation of multi-angle interferometry are described. General holographic interferometry are not able to measure the discontinuous object because of the phase unwrapping. However, in this method, holographic interferograms are generated by object beam and reference beam with different incident angles. Height information of every point at the object surface is extracted independently without the phase unwrapping. The results of simulation demonstrate that this method can be used for measuring the complicated and discontinuous object. It will be useful for the measuring the large and complex discontinuous surfaces often exist in mechanical machining.