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21.
合成二氧化硅对硅橡胶性能的影响 总被引:5,自引:0,他引:5
介绍了合成二氧化硅及硅橡胶的结构性质,探究了二氧化硅的结构性质对硅橡胶补强性能的影响,指出了二氧化硅颗粒的大小、形态、聚结状态、表面性质和与高分子硅氧烷之间的相互作用是影响二氧化硅对硅橡胶补强性能的最主要的因素,并用实验对硅橡胶的硬度、拉伸强度、300%定伸应力、扯断伸长率、撕裂强度、压缩永久变形等物理性能进行测定,结果表明:BET比表面积180~200m^2/g,孔隙度(吸油量)为3.0~3.2mL/g,平均粒径为8~10岬的沉淀法白炭黑对硅橡胶具有很好的补强效果。 相似文献
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Commutative Encryption and Watermarking (CEW) is a technology combined with encryption and watermarking, which is used for providing comprehensive security protection for multimedia information. This paper presents a novel CEW scheme based on orthogonal decomposition. Different from current CEW, the proposed CEW not only achieves the integration of encryption and watermarking in the final data but also has no specific restrictions in selecting encryption and watermarking algorithms. Therefore, the proposed CEW possesses higher security and applicability. Experimental results demonstrate that the proposed CEW can keep the performances of selected encryption and watermarking algorithm and show more robustness than other current CEW schemes. 相似文献
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Yanyan Dai Suk Gyu Lee 《International Journal of Control, Automation and Systems》2014,12(5):1077-1089
This paper deals with the problem of formation control for nonholonomic mobile robots under a cluttered environment. When the obstacles are not detected, the follower robot calculates its waypoint to track, based on the leader robot’s state. The proposed geometric obstacle avoidance control method (GOACM) guarantees that the robot avoids the static and dynamic obstacles using onboard sensors. Due to the difficulty for the robot to simultaneously get overall safe boundary of an obstacle in practice, a safe line, which is perpendicular to the obstacle surface, is used instead of the safe boundary. Since GOACM is executed to find a safe waypoint for the robot, GOACM can effectively cooperate with the formation control method. Moreover, the adaptive controllers guarantee that the trajectory and velocity tracking errors converge to zero with the consideration of the parametric uncertainties of both kinematic and dynamic models. Simulation and experiment results present that the robots effectively form and maintain formation avoiding the obstacles. 相似文献
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孙艳艳 《网络安全技术与应用》2014,(8):206-206
多媒体技术运用在高校音乐教学课堂中,不仅能为高校学生们营造一个生动的学习环境,吸引学生的兴趣,还能让学生直观地欣赏音乐,从而在在轻松的氛围中学习音乐知识,提高自己的音乐鉴赏水平。本文主要研究多媒体技术在高校音乐教学中的作用以及多媒体技术在高校音乐教学中的具体应用。 相似文献
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随着大数据时代的全面来临,大数据分析技术下的信息安全问题逐渐引起社会各界的普遍关注,受多种因素影响,大数据环境下数字档案馆信息安全呈现出新特点,对信息安全保障建设提出更高要求。 相似文献
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Biogenic coalbed gas,how it is generated and the geochemical characteristics of the gas are gaining global attention.The ways coalbed gas is generated,the status of research on the generation mechanism and the methods of differentiating between biogenic gasses are discussed.The generation of biogenic coalbed methane is consistent with anaerobic fermentation theory.Commercial biogenic coalbed gas reservoirs are mainly generated by the process of CO2 reduction.The substrates used by the microbes living in the coal include organic compounds,CO2,H2 and acetate.The production ratio and quantity of biogenic coalbed methane depend on the exposed surface area,the solubility and permeability of the coal and the microbial concentration in the coal seam.It is generally believed that biogenic coalbed gas has a value for σ13C1<-5.5%,C1/C1+>0.95.The H isotope ratio is controlled by both the environment and the generation mechanism:typically σD1<-20%.Biogenic methane formed by CO2 reduction has more σD1 than that formed by acetate fermentation. 相似文献
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A Double Shear Model(DSM)was used in a numerical simulation on bolted rock joint shearing performance.An entire bolt deformed as the letter"U"under a shear load between two joints.Near the bolt-joint intersection,the bolt partly deformed as the letter"Z".There were two critical points along the bolt: one was at the bolt-joint intersection with zero bending moment and the other at the maximum bending moment(plastic hinge)with zero shear stress.The blocks on two sides slid along the bolt as it deformed.A separation area was found between the two joint contact surfaces of the middle rock block and sided block.This area of separation was related to bolt diameter and external forces.We assume that this area is related to the work of external forces.Further research is needed. 相似文献