Search

In this work, the effect of Cu addition on the microstructure and corrosion passivation behavior of Sn alloyed ferritic stainless steel in 3.5 wt.% NaCl solution at 30 °C was investigated by optical microscope (OM), scanning electron microscope (SEM), energy-dispersion spectrum (EDS), potentiodynamic polarization curve and x-ray photoelectron spectroscopy (XPS). The results indicate that Cu addition has certain effect on grain refinement of ferritic stainless steel. Meanwhile, Cu addition has little influence on the cathodic corrosion process of ferritic stainless steel in 3.5 wt.% NaCl solution but shows beneficial effect on enhancing both the corrosion resistance of steel substrate and its passivation behavior. It has been found that the deposition of Cu particles at the bottom of corrosion pits is responsible for the better corrosion resistance and passivation behavior of ferritic stainless steel. Moreover, there is synergistic effect between Sn and Cu on enhancing the corrosion resistance of ferric stainless steel matrix and improving its passivation behavior in NaCl solution.

Additional file 1: Table S1. Composition and calculated nutrient content. Table S2. Primers used for real-time PCR quantification of duck target organisms. Table S3. The length, weight, and content pH value of ileum response to E. coli and dietary RS treatment. Fig. S1. Responses of performance and tibia growth to dietary RS and β acid in ducks subjected E. coli injection. Fig. S2. Effect of RS diet and β acid on bone formation, and calcium (Ca) and phosphorus (P) concentration in meat ducks subjected E. coli injection. Fig. S3. MI-2 treatment has no apparent effect on performance and tibia growth in ducks subjected E. coli injection.

k]The formation mechanism of acicular ferrite and its microstructural characteristics in 430 ferrite stainless steel with TiC additions were studied by theory and experiment. Using an “edge-to-edge matching” model, a 5.25 mismatch between TiC (FCC structure) and fer-ritic stainless steel (BCC structure) was identified, which met the mismatch requirement for the heterogeneous nucleation of 430 ferritic stainless steel. TiC was found to be an effective nucleation site for the formation of acicular ferrite in a smelting experiment, as analyzed by metallographic examination, Image-Pro Plus 6.0 analysis software, and SEM-EDS. Furthermore, small inclusions in the size of 2–4 μm increased the probability of acicular ferrite nucleation, and the secondary acicular ferrite would grow sympathetically from the initial acicular ferrite to produce multi-dimensional acicular ferrites. Moreover, the addition of TiC can increase the average microstrain and dislocation density of 430 ferrite stainless steel, as calculated by Williamson-Hall (WH) method, which could play some role in strengthening the dislocation.

The effect of Ce on the microstructure, mechanical properties and corrosion resistance of 27Cr-3.8Mo-2Ni super-ferritic stainless steel were investigated by FactSage 7.2, OM and SEM. The results re...

Inspired by the idea of mobile targets localization by the antenna array, a novel localization methodology for the partial discharge (PD) source in power systems is proposed by using ultra-high frequency (UHF) sensor-arrays in this paper. Due to the broadband feature of UHF-signals emitted from PD source, a focusing algorithm, i.e., two-sided correlation transformation (TCT) algorithm, is utilized to transform the PD signals to the narrowband ones, which improves the accuracy of the direction-of-arrival (DoA) estimation at the sensor-array under the severe electromagnetic surroundings. Then, with the DoAs obtained from multiple sensor-arrays, a spatial localization paradigm for the PD source is introduced. Finally, the PD source can be localized within a spatial sphere formed by the multiple skew DoA-lines from these sensor-arrays. Based on the simulation with the experimental PD UHF-signal data, it is shown that the proposed methodology accurately localizes the PD source within the a small range of sphere under the severe testing situations, which improves the accuracy of PD source localization compared with the classic time-difference-of-arrival (TDoA) method.

Seafloor deformation or displacement in methane hydrate production areas is a significant environmental problem that can cause considerable damage. This paper describes a conceptual design for monitoring seafloor deformation that differs from existing monitoring methods that include acoustic and pressure sensors, which have high costs and are only suitable for detecting vertical deformation. The proposed monitoring system is vertically mounted in each monitoring well to detect the displacement of submarine soil layers at different depths and to provide visual feedback by displaying three-dimensional images in real time. To reduce the drift error and to obtain more reliable angle estimates, a Kalman filter algorithm is used to combine the data that are measured using a gyroscope and a digital compass. The stability and accuracy of the system are tested both in real-time test and off-line experiment, and the total errors of the azimuth and tilt angle are less than 0.03° and 0.19° in the static off-line experiment, respectively.

We propose an improved phase difference of arrival (PDOA) scheme for indoor visible light positioning (VLP), which avoids using local oscillators (LOs) at the receiver and synchronization between the transmitters and the receiver. The proposed scheme can considerably reduce system complexity, relax the frequency allocation constraints, and improve the positioning accuracy.

This paper proposes an underwater visual simultaneous localization and mapping system using a stereo camera. In front-end, the image data is used to execute feature detection and matching. And the vehicle motion is estimated by the feature matching result. In back-end, a global optimization method represented by a graph, is used to eliminate the errors. The mapping result is in the from 3-D point cloud, which is established by the information from color image and depth image.

This paper describes a method to reconstruct the three-dimensional aspects of underwater objects using side-scan sonar images. The sonar images are segmented into three kinds of regions: echo, shadow and background. A two-dimensional intensity map is estimated from the echoes and a two-dimensional depth map is computed from the shadow information. With the transformation model, the final reconstruction merges these two maps to generate three-dimensional point cloud images of underwater objects.

Permanent magnet DC contactor has the advantages of simple structure, low energy consumption and low noise. A magnetic system structure applicable to DC contactor is presented in this paper. Based on the traditional structure of single coil and single stable position contactor, an auxiliary gas gap is added. By changing the size of the gas gap to change the attraction of permanent magnet, the whole magnetic system improves the reliability of breaking-closing operating. A mathematical model of the magnetic system is established, and the magnetic field and the stationary characteristic are calculated by using finite element method. According to the calculations, cooperation between attraction characteristics and counterforce characteristics is analyzed and the result indicates that the magnetic system, which has a advantages of strong electromagnetic actuation, reliable breaking, manual resetting without disassembly, can be used in industrial production.

In order to discover the hidden information of the urban runoff characteristics,three different statistical techniques were applied on the monitoring data of three catchments with different urban surface type in Macau. The measurementworks were carried out during the rain periods from June 2005 to September 2006, and the water parameters such as pH, TSS, COD, TOC, TN, TP, Zn, Pb, and Cu was analyzed. Univariate statistical analysis, regression analysis and Principal Component Analysis were undertaken on the three catchments separately. The standard deviation (SD) for TSS, COD, TN, and TOC from YLF, ELH Park, and SXY roadway catchments is great. And the regression analysis shows the TSS has a close correlation between TN, TP, TOC or COD. Further, principal component analysis (PCA) was chosen to explain the type of pollution source and its mechanism indifferent urban surface type catchments, which had clarified the linkages between various pollutant parameters from urban runoff and correlations with different urban surface types. According to the above statistical analysis, it could be concluded that the structural best management practices (BMPs) such as detention basins or sedimaterial in the urban runoff pollution of Macau.

The Hough transform (HT) is analyzed and applied to radar weak target detection and location in this paper. The literature, in which only search radar is used, is extended to more general radar system. The theoretical analysis and experimental results used real-life radar data show that the presented method performs well in the strong clutter background, and robust to the clutter distribution.