New polyimide–silica organic–inorganic hybrids

A series of polyimide–silica hybrid films with silica contents up to 30 wt % were successfully prepared by the sol‐gel reaction of tetraethoxysiliane in the presence of poly(amic acid) containing pendent hydroxyl groups. The films were yellow and transparent when the silica content was less than 11 wt %. The chemical structure of the films was characterized by Fourier transform infrared spectroscopy, and the morphology of the films was investigated by scanning electronic microscopy and atomic force microscopy. Thermogravimetric analysis, differential scanning calorimetry, and stress–strain tests were used to measure the performance of the films. The results indicate that the glass‐transition temperatures and decomposition temperatures of the hybrid films increased with increasing silica content, whereas the tensile strength had a maximum with the variety of silica contents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2210–2214, 2003     

A parallel image encryption method based on compressive sensing

Recently, compressive sensing-based encryption methods which combine sampling, compression and encryption together have been proposed. However, since the quantized measurement data obtained from linear dimension reduction projection directly serve as the encrypted image, the existing compressive sensing-based encryption methods fail to resist against the chosen-plaintext attack. To enhance the security, a block cipher structure consisting of scrambling, mixing, S-box and chaotic lattice XOR is designed to further encrypt the quantized measurement data. In particular, the proposed method works efficiently in the parallel computing environment. Moreover, a communication unit exchanges data among the multiple processors without collision. This collision-free property is equivalent to optimal diffusion. The experimental results demonstrate that the proposed encryption method not only achieves the remarkable confusion, diffusion and sensitivity but also outperforms the existing parallel image encryption methods with respect to the compressibility and the encryption speed.     

A noisy-smoothing relevance feedback method for content-based medical image retrieval

In this paper, we address a new problem of noisy images which present in the procedure of relevance feedback for medical image retrieval. We concentrate on the noisy images, caused by the users mislabeling some irrelevant images as relevant ones, and a noisy-smoothing relevance feedback (NS-RF) method is proposed. In NS-RF, a two-step strategy is proposed to handle the noisy images. In step 1, a noisy elimination algorithm is adopted to identify and eliminate the noisy images. In step 2, to further alleviate the influence of noisy images, a fuzzy membership function is employed to estimate the relevance probabilities of retained relevant images. After noisy handling, the fuzzy support vector machine, which can take into account different relevant images with different relevance probabilities, is adopted to re-rank the images. The experimental results on the IRMA medical image collection demonstrate that the proposed method can deal with the noisy images effectively.     

高职院校特色专业监控体系建设研究

近年来,高职院校都比较注重特色专业的建设。其中,特色专业建设的监控体系也受到了高职院校的重视,并取得了一定的效果,同时,也给其他院校提供了有价值的参考和借鉴。但由于在认识水平、管理水平和教学水平等方面仍有一些问题,导致在监控过程和措施实施方面还存在许多疏漏,有待完善。     

酸性镀锡液的新进展

从近几年美国发明专利的角度扼要综述酸性镀锡液的新进展。说明酸性镀锡液由氟硼酸盐型发展为烷基磺酸盐型的改进过程。列出参考文献９篇。     

基于MAX+PLUSII模块化设计的智力竞赛抢答器

设计了一款造价低,体积小,操作简单,适用性广的抢答器。该抢答器是基于MAX+PLUSII软件,在FPGA芯片上设计的,可实现多人智力竞赛抢答。     

氯化聚乙烯接枝氯乙烯聚合速率及传热

本文用气相色谱技术研究氯化聚乙烯(CPE)-接枝(g)-氯乙烯(VC)聚合动力学,对不同引发剂体系分析热负荷分布,并对7 m~3聚合釜传热面进行校核。     

CaO-SiO2系玻璃的析晶动力学研究

利用溶胶-凝胶法制得CaO-SiO2系基础玻璃,通过差热分析曲线分析质量比为CaO-SiO2玻璃的析晶能力。经分析,其析晶活化能E=457.1kJ·mol-1,而晶化生长指数是随升温速率的不同而不同,速率越大,晶化生长指数越小。     

锆莫来石材料的反应烧结机制和显微结构特征

研究了用锆英石和工业氧化铝合成锆莫来石材料的反应烧结过程和显微结构。结果表明，添加适量ＭｇＣｌ２·６Ｈ２Ｏ可以促进反应烧结进程。锆英石大颗粒完全分解以后形成ＺｒＯ２聚集体，结构中出现封闭气孔可能与ＺｒＯ２聚集体有密切关系。加入ＭｇＣｌ２·６Ｈ２Ｏ后锆莫来石材料显微结构的主要特征：ＺｒＯ２有聚集体和均匀分布两种赋存形式；封闭气孔一般与ＺｒＯ２聚集体相邻。     

聚合转化率对硫调型氯丁胶结构与性能的影响

研究了硫调型氯丁橡胶乳液聚合中转化率对产晶结构与性能的影响.结果表明,随单体转化率的提高,聚合物的凝胶量及其交联密度增大,致使断链速度减慢,所得断链胶的门尼粘度上升,残存凝胶量增加,分子支化程度增大,分子量分布变宽,焦烧时间缩短。而相应硫化胶的拉伸强度、撕裂强度、冲击弹性和硬度等提高,扯断伸长率和永久变形下降。这些变化一般在转化率为80——85％时有明显转折.综合考虑产量与质量,聚合转化率控制在82±2％较为适宜。