基于时域相关性的快速HEVC帧间模式判决方法

高效率视频编码(HEVC)相比目前的国际视频编码标准H.264/AVC,在压缩率方面有了较大的提高,但也带来了巨大的编码计算复杂度。为了降低HEVC的编码计算复杂度,提出了一种快速HEVC帧间模式判决方法。统计并分析了相邻两帧之间对应块的编码单元(CU)和预测单元(PU)的时域相关性,在此相关性基础上,跳过了一些冗余CU分割层和PU预测模式,CU层最多只取两种PU预测模式,从而大大减少了所需要进行的率失真代价计算的数量,实验结果显示,与HM7.0相比,该方法在仅损失了0.21%-1.66%的压缩率和0.01~0.09 dB的峰值信噪比的前提下,降低了52.3%~63.5%的编码时间。     

高性能SPU建筑用密封胶的研制

研究了补强剂纳米碳酸钙的种类、用量以及增稠触变剂的种类对SPU密封胶性能的影响。结果表明,SPU密封胶的拉伸强度随碳酸钙用量的增加而增大,在用量为200质量份时强度达到最大值;添加了聚酰胺SL的密封胶具有出色的触变性,而添加气相二氧化硅R812S则在成本、性能等方面具有优势。     

高性能胶黏剂密封剂在航天工业领域的应用

对航天产品用胶黏剂密封剂的特殊要求及热防护层粘接剂、防热密封剂、耐低温胶黏剂、耐空间环境胶黏剂、功能性胶黏剂和复合材料结构胶黏剂等高性能胶黏剂密封剂的性能及其在运载火箭、卫星、飞船和空间站等航天产品上的应用进行了综合评述。     

GRC成就建筑幕墙和屋面艺术之美

GRC(玻璃纤维增强水泥)是近30年来新开发的一种新型复合材料,是运用高新技术对材料进行复合利用的又一重要成果。介绍了GRC材料及特点,GRC建筑幕墙和屋面的特征及实例,GRC幕墙板结构设计及物理力学性能,GRC幕墙的生产与安装,GRC幕墙接缝设计及专用密封胶,并列举了GRC幕墙工程案例。GRC具有轻质、高强、隔热保温、防水、防火、可加工性良好及价格适中等诸多优点,可根据设计意图,通过模板对其表面的纹理和分割进行设计,从而创造出令人赞叹的表面效果。我国建筑行业应尽快推广GRC建筑幕墙和屋面。     

Surface modification of sepiolite particles with polyurethane and polyvinyl alcohol

Sepiolite is a clay mineral that has many industrial applications due to its advantageous properties such as white color, low specific gravity, high absorption capacity, chemical composition and low thermal conductivity. In this study, the effect of the addition of polymers, polyvinyl-alcohol and polyurethane, on the rheological properties of the sepiolite dispersions have been investigated. The rheological parameters of clay suspensions can be used to examine particle–particle interactions. The polymers that have been added to the clay suspensions interact with clay particles, depending on their ionic or non-ionic character. Firstly, the sepiolite dispersions were characterized by the rheological properties, mineral structure and content. Then the effect of the polymers on the flow, structural, and surface properties of sepiolite dispersions was investigated by rheological, electrokinetical, and scanning electron microscopy (SEM) measurements. The measurements showed that polymer molecules bind on the surface of sepiolite particles and changed the flow properties of the dispersions as stable dispersions at some certain concentrations. It is also determined that PU polymer covered the surface of the sepiolite faster than PVA, but the coverage of the PVA was much more smoothly. The thermal properties of the sepiolite improved with PVA more than PU, as a result of the homogenous surface coverage.     

聚氨酯嵌缝材料老化性能初探

为探讨嵌缝材料老化机理及评价指标,选择几种低模量聚氨酯嵌缝材料,研究了嵌缝材料的耐热、耐碱、耐水和耐紫外线老化性能。结果表明,热老化后的材料拉伸强度和拉伸粘结强度明显增大,最高分别增加了156%和117%;材料的耐碱性能较好,碱处理后拉伸性能基本保持不变,但是浸水后粘结性能下降,拉伸粘结强度最高下降了47%;紫外线照射加速了嵌缝材料的老化,表现为材料起皮、龟裂和开裂。提出了增加热老化后拉伸强度上限值和紫外老化后外观来评价嵌缝材料老化性能的建议。     

高释放性净味快干醇酸树脂的研究

系统探讨了醇酸树脂对聚氨酯(PU)涂膜气味残留的影响因素,确定了制备净味醇酸树脂的配方和生产工艺,制备的树脂具有快干、溶剂释放快的特点,应用于PU涂料,不但可解决漆膜气味残留问题,而且提高了涂料性能。     

Defense against primary user emulation attacks from the secondary user throughput perspective

The maximization of Secondary user (SU) throughput has been studied extensively in honest cooperative spectrum sensing (CSS). However, when primary user emulation attacks (PUEAs) are launched, the model of CSS changes. This also necessitates the redesigning of the SU throughput maximisation scheme. In this paper, such redesigning of the SU throughput maximisation scheme under PUEAs has been carried out. Our objective is to suppress the damages caused by the PUEAs on the SU throughput. To serve this purpose, an optimally weighted CSS has been proposed. The optimal weights are obtained by maximising the SU throughput while protecting the primary user (PU) from interference in a network facing the PUEAs. Considering the significance of simplicity and speed in CSS, we apply the Nelder Mead Simplex Algorithm to solve the problem. The experiments carried out endorse the effectiveness of the proposed scheme compared to the existing combination schemes.     

改性脲醛树脂堵漏剂的合成研究

介绍了以甲醛和尿素为原料、聚乙烯醇为改性剂合成改性脲醛树脂的方法。考察了尿素加入方式、甲醛与尿素摩尔比、反应液PH、反应温度及聚乙烯醇用量对脲醛树脂性能的影响。结果表明，在尿素分3次投料，甲醛与尿素摩尔比1．6：1，加成反应阶段温度70℃左右、反应液pH7．5—8，5，缩聚温度85—90℃、反应液pH5．2～5．4，聚乙烯醇用量占甲醛和尿素总量的1.0％条件下，可制得综合性能较好，游离甲醛含量低的低毒脲醛树脂。