In this study, the influence of repair welding on microstructure evolution, mechanical properties, and corrosion resistance of SUS304-Q345B dissimilar metal active gas arc (MAG) welding plates was investigated via optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), hardness, tensile, fatigue, intergranular corrosion, and electrochemical tests, in which the zero (R0), primary (R1), and secondary repair welding (R2) were performed by MAG welding. The results showed that, after repair welding, the δ-ferrite morphology in the weld evolved from a continuous dendritic shape to a dispersed worm-like structure and the bar ferrite in the heat-affected zone of SUS304 (HAZSUS304) evolved into short bar ferrite. The grain size of the weld was reduced due to the remelting caused by repair welding. The hardness of the weld increased first and then decreased which was related to the decrease of δ-ferrite morphology and grain size of weld. In the tensile test, all specimens were fractured at Q345B base material (BMQ345B), which revealed that repair welding had little effect on the tensile properties. The fatigue limit strength of R1 didn't reduce significantly, while the fracture position of R2 transferred from the SUS304 base material (BMSUS304) to the fusion line of SUS304 (FLSUS304). The corrosion resistance of R1 weld possessed the best corrosion resistance owing to the finer grain size and better δ-ferrite morphology. The results indicated that repair welding was feasible for the repair and reuse of welded joints, and it was of great importance in engineering applications of welded plates.
Since 1997, Language Teaching Research (LTR) has published hundreds of research articles, most of which have reported on empirical studies whose broad purpose was to increase understanding on how second or foreign language teaching can be improved. These articles, as a collective whole, can be viewed as an artifact of the research issues and topics that interested LTR scholars in the time period around the beginning of the 21st century. Moreover, because of the journal’s special focus on research, a survey of the first 20 years of LTR’s articles holds the potential to monitor the field at large over that time period. Via a survey that examines the main focuses of each of the 359 articles under categories as ‘Instructional effects’, ‘Teacher cognition’ and ‘Learner behavior’, this study serves as an extant inventory of research interests over the first 20 years of the journal’s existence.
Objective To study the visual areas of human cortex by functional MRI(fMRI) retinotopic mapping.Methods Six normal volunteers were examined with 1.5 T MRI scanner,and stimulated with the pattern of phase-encoded polar angle with clockwise or counterclockwise rotating wedges, and the pattern of eccentricity with concentric expanding or contracting rings.After the data preprocessing with realignment,register,the functional data with phase-encoded of visual cortex were analyzed with fourier transform to obtain phase delay of each voxel.Visual field sign(VFS)was calculated based on the coding information of eccentricity gradient and polar angle gradient.Visual field representations were determined by VFS.The visualizations were performed with 2-dimension and 3-dimensions methods.Results In all subjects,the visual areas of V1,V2,V3/VP,V3A/V4v and the higher visual areas of V7 and V8 were delineated clearly.The visual areas were distributed on the occipital cortex as topological frame.Conclusion The technique of functional MRI retinotopic mapping can measure the retinotopic organization of human visual cortex non-invasively and precisely.
This chapter reviews efforts to examine the construction and content of media products, and the role of the mass media in the language policymaking process, with a particular focus on framing in mass media coverage. The authors first elaborate what they mean by the term framing. Then they illustrate how the concept of framing can help researchers to explore the media’s mediation of language policymaking in three specific debates: the dialect crisis in China; high-stakes English examinations in China; and medium of instruction policy, with particular attention to the use of English, Cantonese, and Putonghua in Hong Kong and the use of English and Spanish in the US state of Arizona. The chapter concludes with suggestions for expanding research on the role of mass media in language policymaking.
Multimedia no longer is the traditional auxiliary teaching tool, but to construct one kind of new network teaching environment to create the condition, specially regarding the education socialization, the multimedia networks is one kind of more ideal dissemination tool. Multimedia itself has: The fusion lives, the misalignment, not to have the constitutive property, the negotiation, to be possible mutually, timeliness characteristics and so on editor; Simultaneously utilizes in the education teaching also has its special skill: Favors the information the memory use, is raises the divergent thought the tool, to urge the study individualizing realization. The foothold will develop in the future, uses the multimedia networking, the development teaching experiment.
Along with the rapid development of China's urbanization,the population of land-lost peasants is increasing,and their citizenship is the requirement of social development.Based on the theoretical perspective of social inclusion,the citizenship of land-lost peasants is facing with the economic,institutional and psychological barriers.We should provide an approach for the land-lost peasants to be melt into the urban society,such as reforming land expropriation compensation system,improving the social security and employment training system of land-lost peasants,and setting up the community organization platform.
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