Optimal surface profile design of deployable mesh reflectors via a force density strategy

Based on a force density method coupled with optimal design of node positions, a novel approach for optimal surface profile design of mesh reflectors is presented. Uniform tension is achieved by iterations on coefficients of force density. The positions of net nodes are recalculated in each iteration so that the faceting RMS error of the reflector surface is minimized. Applications of both prime focus and offset configurations are demonstrated. The simulation results show the effectiveness of the proposed approach

Design optimization of TBM disc cutters for different geological conditions

A novel optimization methodology for the disc cutter designs of tunnel boring machines (TBM) was presented. To fully understand the characteristics and performance of TBM cutters, a comprehensive list of performance parameters were investigated, including maximum equivalent stress and strain, specific energy and wear life which were closely related to the cutting forces and profile geometry of the cutter rings. A systematic method was employed to evaluate an overall performance index by incorporating objectives at all possible geological conditions. The Multi-objective & Multi-geologic Conditions Optimization (MMCO) program was then developed, which combined the updating of finite element model, system evaluation, finite element solving, post-processing and optimization algorithm. Finally, the MMCO was used to optimize the TBM cutters used in a TBM tunnel project in China. The results show that the optimization significantly improves the working performances of the cutters under all geological conditions considered

The Rising of the Avant-Garde Movement In the 1980s People’s Republic of China: A Cultural Practice of the New Enlightenment

This dissertation, entitled “The Rising of the Avant-garde Movement in 1980s People’s Republic of China: A Cultural Practice of the New Enlightenment,” deals with Chinese avant-garde literature and art in the reform era of the 1980s, when the People’s Republic of China was turning from high socialism to state capitalism. Scholars of Chinese studies have deemed avant-garde texts as counter-narratives of enlightenment, which was a main ideology and national agenda of the reform era. This dissertation reexamines this established statement by shifting focus from the traditional hermeneutic approaches to a sociological study of the generative conditions of avant-garde literature and art. Responding to the thematic preoccupation with individual avant-garde artists and works in various scholarly monographs and literary and art history, I take literary and art journals and newspapers in which avant-garde works were primarily published and discussed as the object of observation. The three content chapters, by focusing on the official literary magazine, Shanghai Literature , the self-printed unofficial poetry journals, Them, At Sea, and Not-Not, and the semi-official art newspaper Fine Arts in China, examine the dialogic and conflicting relationships of the Avant-garde with socialist cultural production. They also delineate the generative trajectory Chinese experimental literature and art, in correspondence with China’s economic reform starting from the mid- 1980s. This dissertation treats the avant-garde as a cultural movement in the form of groups rather than individual texts and artists. This movement is related to the change of knowledge system, the reform of institutions, and the conflict and complicity among different cultural fields. Predicated on this conception, it investigates how the avant-garde engaged in the reform era by practicing and reflecting on the national discourse of the New Enlightenment. This research leads to a more complicated understanding of Chinese avant-garde in terms of its relationship with the official cultural field, of its deviating and transitional doubleness in the history of the Post-Mao Era, and of its great ambiguity in the growing discrepancy between two forms of enlightenment, namely, industrial modernization and aesthetic modernity

Gravitation-Based Edge Detection in Hyperspectral Images

Edge detection is one of the key issues in the field of computer vision and remote sensing image analysis. Although many different edge-detection methods have been proposed for gray-scale, color, and multispectral images, they still face difficulties when extracting edge features from hyperspectral images (HSIs) that contain a large number of bands with very narrow gap in the spectral domain. Inspired by the clustering characteristic of the gravitational theory, a novel edge-detection algorithm for HSIs is presented in this paper. In the proposed method, we first construct a joint feature space by combining the spatial and spectral features. Each pixel of HSI is assumed to be a celestial object in the joint feature space, which exerts gravitational force to each of its neighboring pixel. Accordingly, each object travels in the joint feature space until it reaches a stable equilibrium. At the equilibrium, the image is smoothed and the edges are enhanced, where the edge pixels can be easily distinguished by calculating the gravitational potential energy. The proposed edge-detection method is tested on several benchmark HSIs and the obtained results were compared with those of four state-of-the-art approaches. The experimental results confirm the efficacy of the proposed method

Oersted Field and Spin Current Effects on Magnetic Domains in [Co/Pd]

An out-of-plane Oersted field produced from a current-carrying Au wire is used to induce local domain formation in wires made from [Co/Pd][subscript 15] multilayers with perpendicular anisotropy. A 100 ns pulsed current of 56-110 mA injected into the Au wire created a reverse domain size of 120-290 nm in a Co/Pd nanowire on one side of the Au wire. A Biot-Savart model was used to estimate the position dependence of the Oersted field around the Au wire. The shape, size, and location of the reversed region of Co/Pd were consistent with the magnitude of the Oersted field and the switching field distribution of the unpatterned film. A current density of 6.2 × 10[superscript 11] Am[superscript -2] in the Co/Pd nanowire did not translate the domain walls due to low spin transfer efficiency, but the Joule heating promoted domain growth in a field below the coercive field.National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Award DMR1419807