At present, the basic technical principle in China is to adopt polymers to modifying the properties of mortar so as to improve the crack-resistance of construction structures and to strengthen their water-resisting an...At present, the basic technical principle in China is to adopt polymers to modifying the properties of mortar so as to improve the crack-resistance of construction structures and to strengthen their water-resisting and climate-resisting properties as well. However, how polymer acts on anti-crack mortar is short of systematic research. Theoretical exposition of polymer mortar is basically explained by Ohama Model, which is cement slaking and polymer coating are carried on together and mutually-cross web structure interweaved with liquid and polymer coating. But anti-crack mortar has its own special characteristics because of fewer polymers mixed in it and its high viscosity. So this paper is to showing how different polymers affect its crack-resistance cannot be reflected from this theory. Vinyl-acetate ethylene (VAC/E) has been selected as representation of polymerization, whose property is modified by compounding it from some inorganic components, such as talc, CaCO3 and so on. And then the mechanics property and shrinkage of anti-crack polymer mortar is tested when different amount of polymers is added as admixture of mortar. The result indicates that, the working performance and mechanics property of the polymer mortar are worse mixed VAC/E only. It basically meets the demands for mechanics strength and working performance when mixed both VAC/E and CaCO3 While it achieves much better mechanical property and working performance than the two former when mixed VAC/E, talc and CaCO3; the result of corresponding scanning electron microscopy (SEM) of sample indicates that the internal result of the polymer mortar, compared with classical Ohama Model, has a particularity that its structure is formed by polymer coating instead of filling up the intervals among cement grains.展开更多
American campaigning has become increasingly complex as it adjusts to our ever-changing cultural landscape. The use of electronic media in the presidential campaigns of 1960 and 2008 is illustrative of this shift. A c...American campaigning has become increasingly complex as it adjusts to our ever-changing cultural landscape. The use of electronic media in the presidential campaigns of 1960 and 2008 is illustrative of this shift. A content analysis of these two campaigns demonstrates how each applied the newest technologies available at the time to define the candidate's image and export the messages to the electorate. Whether it be Kennedy's use of television or Obama's usage of social media, the role that new media of the day played in both campaigns clearly set the tone for future political campaigns. This examination of the role of media in both elections serves to form a primer for how the successful applications of new media lead to campaign victory. Then and now, the growing influence of new technologies on campaigning makes it necessary to compare and contrast the successful usages and strategies employed. The need for continuing analysis will grow in the coming years.展开更多
基金Funded bv "863" Proaram of China (No. 2005AA332010)
文摘At present, the basic technical principle in China is to adopt polymers to modifying the properties of mortar so as to improve the crack-resistance of construction structures and to strengthen their water-resisting and climate-resisting properties as well. However, how polymer acts on anti-crack mortar is short of systematic research. Theoretical exposition of polymer mortar is basically explained by Ohama Model, which is cement slaking and polymer coating are carried on together and mutually-cross web structure interweaved with liquid and polymer coating. But anti-crack mortar has its own special characteristics because of fewer polymers mixed in it and its high viscosity. So this paper is to showing how different polymers affect its crack-resistance cannot be reflected from this theory. Vinyl-acetate ethylene (VAC/E) has been selected as representation of polymerization, whose property is modified by compounding it from some inorganic components, such as talc, CaCO3 and so on. And then the mechanics property and shrinkage of anti-crack polymer mortar is tested when different amount of polymers is added as admixture of mortar. The result indicates that, the working performance and mechanics property of the polymer mortar are worse mixed VAC/E only. It basically meets the demands for mechanics strength and working performance when mixed both VAC/E and CaCO3 While it achieves much better mechanical property and working performance than the two former when mixed VAC/E, talc and CaCO3; the result of corresponding scanning electron microscopy (SEM) of sample indicates that the internal result of the polymer mortar, compared with classical Ohama Model, has a particularity that its structure is formed by polymer coating instead of filling up the intervals among cement grains.
文摘American campaigning has become increasingly complex as it adjusts to our ever-changing cultural landscape. The use of electronic media in the presidential campaigns of 1960 and 2008 is illustrative of this shift. A content analysis of these two campaigns demonstrates how each applied the newest technologies available at the time to define the candidate's image and export the messages to the electorate. Whether it be Kennedy's use of television or Obama's usage of social media, the role that new media of the day played in both campaigns clearly set the tone for future political campaigns. This examination of the role of media in both elections serves to form a primer for how the successful applications of new media lead to campaign victory. Then and now, the growing influence of new technologies on campaigning makes it necessary to compare and contrast the successful usages and strategies employed. The need for continuing analysis will grow in the coming years.