聚硅烷的热分解动力学研究

用热重法（ＴＧＡ）研究了聚（甲基环己基硅烷）、甲基环己基硅烷与甲基苯乙基硅烷共聚物和聚（甲基苯乙基硅烷）的热分解动力学，计算了热分解动力学参数。结果表明，其热分解活化能分别为２０８ｋＪ／ｍｏｌ、１８７ｋＪ／ｍｏｌ和１１４ｋＪ／ｍｏｌ；这３者的热分解均符合无规引发裂解模型。     

碳纳米管的聚硅烷改性

对多壁碳纳米管纯化、酸化、酰氯化,并在酰氯化的碳纳米管表面接枝对苯二酚、甲基乙烯基二氯硅烷,最后接枝聚硅烷。研究结果证明:红外光谱和扫描电镜显示聚合物接上了碳纳米管;酸碱滴定分析显示加有5mL硫酸的5.8mol/L的硝酸酸化的碳纳米管羧基含量最高。     

聚硅烷光学材料的研究与应用

聚硅烷是一种主链完全由Si-Si组成的高聚物,其主链的σ键电子的非定域作用赋予了聚硅烷独特的光电性质,从而使其成为极有前途的功能性材料,引起了人们极大的兴趣,成为材料科学的研究热点之一.在前人研究的基础上,概述了聚硅烷的合成方法和光学性能及其在非线性光学材料、光致抗蚀剂和电致发光材料等方面的研究与应用.     

含双键聚硅烷的电化学合成

采用电化学合成法,以三氯甲基硅烷和烯丙基氯为单体合成出含有双键的聚硅烷,通过FT-IR,GPC,1H-NMR表征了其结构。研究了单体配比、单体浓度、电极材料、反应电量、换向时间和电解质浓度对含双键聚硅烷电化学合成的影响。结果表明,三氯甲基硅烷与氯丙烯的比率为3/1,电极为镁电极时,重均分子量和双键保留率达到了最高值,分别为3749和12.6%。增加反应电量、缩短换向时间和降低单体浓度都可以提高产物的分子量和产率。     

电化学合成聚硅烷的反应速率

采用电化学法,合成出含双键聚硅烷与不含双键聚硅烷,通过FT-IR,UV,1H NMR表征其结构.分别研究了电化学反应体系和直接化学反应体系中Si-Cl键含量的变化,以及加入引发剂蒽对反应速率的影响.结果表明:含双键聚硅烷的合成反应速率快于不含双键的聚硅烷,相同反应电量下含双键聚硅烷反应体系中的Si-Cl键含量比不含双键聚硅烷少10%～15%;在电化学合成聚硅烷的过程中,单体与镁发生的格氏反应在整个反应中占有相当的比例;引发剂蒽的加入能够有效地提高不含双键聚硅烷的反应速率.本文还对电化学合成聚硅烷的反应机理进行了推测.     

电化学合成的含双键聚硅烷

采用电化学合成法,将甲基三氯硅烷与烯丙基氯进行聚合,合成出带有双键的聚硅烷,通过FT-IR,UV,1H-NM R,GPC表征了其结构,测定了产物的双键含量,并对产物进行了交联固化和高温裂解实验。结果表明,产物中双键保留率为8.2%,双键的引入使聚硅烷获得了很高的质量保留率及较高的陶瓷产率。     

紫外正性光致抗蚀剂的研究进展及应用现状

酚醛树脂-重氮萘醌型正性光致抗蚀剂主要适用于436nm(G线)～365nm(I线)的紫外曝光区域,是目前电子和PS版工业中使用最多的正性抗蚀材料.本文介绍了近年来该类抗蚀剂的国内外进展情况,并对其各个组分进行了归纳综述.     

新型功能聚硅烷的研究进展

聚硅烷（-SiR2-SiR2-)是一种由无机元素组成主链的长链聚合物，主链中的硅原子具有3d空轨道，σ电子沿主链广泛离域，由此所产生的紫外吸收，半导体性能等应用于发光材料，光记忆材料、电导体和光导体。本文介绍了国内外关于聚硅烷的研究进展，包括聚硅烷的性能和应用，以及聚硅烷的共聚改性和分子自组装。     

聚硅烷陶瓷先驱体研究进展

具有σ-共轭结构特点的聚硅烷有着特殊的性能及用途。概述了聚硅烷作为陶瓷先驱体在制备陶瓷纤维、多孔陶瓷、陶瓷基复合材料3个方面的应用研究进展,并针对目前存在的不足指出了今后的研究方向。     

Brightness preserving bi‐level fuzzy histogram equalization for MRI brain image contrast enhancement

In this article, brightness preserving bi‐level fuzzy histogram equalization (BPFHE) is proposed for the contrast enhancement of MRI brain images. Histogram equalization (HE) is widely used for improving the contrast in digital images. As a result, such image creates side‐effects such as washed‐out appearance and false contouring due to the significant change in brightness. In order to overcome these problems, mean brightness preserving HE based techniques have been proposed. Generally, these methods partition the histogram of the original image into sub histograms and then independently equalize each sub‐histogram. The BPFHE consists of two stages. First, fuzzy histogram is computed based on fuzzy set theory to handle the inexactness of gray level values in a better way compared to classical crisp histograms. In the second stage, the fuzzy histogram is divided into two sub‐histograms based on the mean intensities of the multi‐peaks in the original image and then equalizes them independently to preserve image brightness. The quantitative and subjective enhancement of proposed BPBFHE algorithm is evaluated using two well known parameters like entropy or average information contents (AIC) and Feature Similarity Index Matrix (FSIM) for different gray scale images. The proposed method have been tested using several images and gives better visual quality as compared to the conventional methods. The simulation results show that the proposed method has better performance than the existing methods, and preserve the original brightness quite well, so that it is possible to be utilized in medical image diagnosis.     

Single image veiling glare removal

Photographing against a bright light source is difficult since the direct light from the light source causes glare phenomenon in the lens, changing the colour balance and reducing the image contrast within the field of view. To address the effect, we introduce a glare formation model that accounts for the characters of the glare. Based on the model, we propose a single image processing method to remove the glare in the images by decomposing the image into the scene layer and the glare layer. We then adjust the brightness and the colour balance of the scene layer to eliminate the influences of the glare. In order to enhance the contrast decreased by the glare, we use a local standard deviation-based contrast enhancement algorithm to boost the details while avoiding excessive enhancement. Experimental results show that the method removes the majority of the glare and improves the local contrast effectively.     

Residual spatial entropy-based image contrast enhancement and gradient-based relative contrast measurement

This paper proposes a novel algorithm to achieve both global and local contrast enhancement using a new definition of residual spatial entropy of gray levels of an image. Residual spatial entropy is utilized to assign a weight to each gray level which is further used in mapping of input gray levels to output gray levels to achieve global contrast enhancement. A non-linear mapping is applied on transform-domain coefficients of image enhanced globally to perform local contrast enhancement. The algorithm allows to control levels of perceived global and local contrast. New definitions of full-reference relative contrast measures are also introduced. Experimental results show that proposed algorithm produces better or comparable contrast-enhanced images than several state-of-the-art algorithms.     

Contrast enhancement dynamic histogram equalization for medical image processing application

Image processing requires an excellent image contrast‐enhancement technique to extract useful information invisible to the human or machine vision. Because of the histogram flattening, the widely used conventional histogram equalization image‐enhancing technique suffers from severe brightness changes, rendering it undesirable. Hence, we introduce a contrast‐enhancement dynamic histogram‐equalization algorithm method that generates better output image by preserving the input mean brightness without introducing the unfavorable side effects of checkerboard effect, artefacts, and washed‐out appearance. The first procedure of this technique is; normalizing input histogram and followed by smoothing process. Then, the break point detection process is done to divide the histogram into subhistograms before we can remap the gray level allocation. Lastly, the transformation function of each subhistogram is constructed independently. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 280‐289, 2011;     

The experimental determination of the neutron cross section for selected solvents

An experiment was conducted in order to determine the macroscopic neutron cross section of various solvents useful in neutron radiographic inspection. These solvents are used to dissolve the salts of high cross-section elements in order to formulate a fluid of maximal neutron cross section. The resulting fluid could then be used as a contrast enhancing agent in neutron radiographic inspection. This experiment was planned using statistical experimental design techniques. The results of this experiment provided a quantitative measure of the mean and standard deviation of the macroscopic neutron cross section for the nine fluids investigated. A control fluid was found to be in close agreement with published values.     

Palmprint enhancement using recursive histogram equalisation

Abstract

Palmprint identification system is one of the most powerful personal identification systems in recent years. In order to achieve high identification accuracy, all parts of the palmprint are needed to be enhanced. Histogram equalisation is a very popular image enhancing technique. A novel histogram equalisation technique, called recursive\ histogram equalisation, for brightness preservation and image contrast enhancement, is put forward in this paper. The essence of proposed algorithm is to decompose an input histogram into two or more sub-histograms recursively based on its mean, change the sub-histograms through a weighting process based on a normalised power law function and then equalise the weighted sub-histograms independently. Experiments show that our method preserves the mean brightness of a given image, enhances the contrast and produces more natural looking images than the other histogram equalisation methods.     

超声波辐照下PB的降解及与AA共聚反应的研究

研究了在超声波辐照作用下聚丁二烯(PB)在环已烷溶液中的降解及与丙烯酸(AA)的共疑反应。结果表明,PB的超声降解符合一般聚合物的力降解规律,降解动力学方程为(?)_t=((?)_0-(?)_∞)exp(-kt)+(?)_∞,k=33.33×10~(-5)(s)。通过IR、NMR研究了所得共聚物的结构,证明所得产物主要为嵌段共聚物。用SEM和IR研究了其聚物对SBR/CaCO_3体系的偶联作用,分析了经共聚物处理的CaCO_3的表面性质和SBR/CaCO_3的断面形貌,证实SBR/CaCO_3体系的相容性及力学性能得到明显的改善。     

一种应用于AC PDP的反gamma校正与动态对比度增强相结合的新方法

由于交流等离子体显示器(AC PDP)的显示特性是线性的,因此在显示接收到的视频信号前必须要进行反gamma校正.同时,为了提高显示器件的画质,必须要进行对比度增强.直方图均衡化是一种重要的对比度增强方法,但直方图均衡化的增强效果不可控,往往由于过增强而导致图像失真.本文结合上述两种技术提出了一种应用于AC PDP的反gamma校正与可控的动态对比度增强相结合算法.该算法能够在对输入视频图像进行反gamma校正的同时,实现幅度可调的动态对比度增强.同时避免了传统直方图均衡化对图像产生的过增强现象.本文实现了基于提出算法的实时图像处理器,并且在50英寸AC PDP上进行了测试.模拟仿真及实际测试结果均表明,本文提出的算法能够使AC PDP的画质得到显著提升.     

MRI brain image enhancement using brightness preserving adaptive fuzzy histogram equalization

In this article, fuzzy logic based adaptive histogram equalization (AHE) is proposed to enhance the contrast of MRI brain image. Medical image plays an important role in monitoring patient's health condition and giving an effective diagnostic. Mostly, medical images suffer from different problems such as poor contrast and noise. So it is necessary to enhance the contrast and to remove the noise in order to improve the quality of a various medical images such as CT, X‐ray, MRI, and MAMOGRAM images. Fuzzy logic is a useful tool for handling the ambiguity or uncertainty. Brightness Preserving Adaptive Fuzzy Histogram Equalization technique is proposed to improve the contrast of MRI brain images by preserving brightness. Proposed method comprises of two stages. First, fuzzy logic is applied to an input image and then it's output is given to AHE technique. This process not only preserves the mean brightness and but also improves the contrast of an image. A huge number of highly MRI brain images are taken in the proposed method. Performance of the proposed method is compared with existing methods using the parameters namely entropy, feature similarity index, and contrast improvement index and the experimental results show that the proposed method overwhelms the previous existing methods.     

一种用于锁定髓内钉的图像导航方法

图像导航是将机器人用于长骨骨折内固定手术中的关键技术．本文首先使用了一种用于定义和改变图像局部对比度的相似性测量方法．避免了图像的过增强和欠增强,然后用局部法对X光图像进行畸变校正;并提出了一种基于几何模型的对准方法,得到一条能够穿过髓内钉远端孔的三维路径,从而引导串联机器人锁定髓内钉．实验结果表明,该方法能够提高图像质量,有足够的定位精度和稳定性,并可以大大减少手术所需时间,降低医生所受辐射剂量．