Infrared Texture Simulation Using Gaussian-Markov Random Fields

Infrared battlefield simulation is a most important subject today to test infrared weapons. The reality and details of simulated scenes are always relied on the infrared textures. A texture is considered to be a stochastic, possibly periodic, two-dimensional image field. A texture model can be described as a mathematical procedure. Markov random field(MRF) model is a famous model to synthesize the visible textures of various kinds. In this paper, the Gaussian-Markov random fields(GMRF) are firstly used to sample the distribution of temperature field on the surface of terrain. And the Planck's radiation law is applied to calculate the emittance in the bands of 35 m or 814 m. The emittance distribution of the terrain can be normalized and colored by the range of 0 to the gray levels decreased by 1. Then an infrared texture is generated by GMRF by given a set of certain parameters.     

A Texture Combined Multispectral Magnetic Resonance Imaging Segmentation for Nasopharyngeal Carcinoma

Tumor segmentation from magnetic resonance imaging (MRI) is important for volume estimation and visualization of nasopharyngeal carcinoma (NPC). In some cases, segmentation using the general multispectral (GM) method often obtained poor results due to the high false positives caused by complex anatomic structures and serious overlap in feature space. In this study, a texture combined multispectral fuzzy clustering (TCMFC) segmentation algorithm was proposed. A texture measure of T1-weighted (T1) MR image was introduced by calculating the two-order central statistical information of every pixel within a window after the window convolution operation. The texture measure and the intensities in T1 and contrast-enhanced T1 images formed the new 3-D feature vector for fuzzy clustering implemented by semi-supervised fuzzy c-means (SFCM). Testing showed that by reducing the false positives significantly, the TCMFC method achieved improved segmentation results, compared with the GM method.     

分数维法对V系催化剂表面的纹理及催化性质的表征

应用计算机纹理分析技术,以分形理论及萘氧化制邻苯二甲酸酐钒系催化剂为样本,通过改变K_2SO_4、P_2O_5助剂含量,研究了多相催化剂的表面形貌.结果表明,催化剂表面分数维D随助剂的含量发生变化,D在极大值时邻苯二甲酸酐的收率最高。     

Microphase separation of block copolymer solutions in a flow field

Films of polystyrene–polybutadiene–polystyrene (PS/PB/PS) triblock copolymer and polystyrene-poly(ethylene/propylene) (PS/PEP) diblock copolymer were cast from toluene solutions subjected to hydrodynamic flow at room temperature using a device based on a novel casting method we term ‘roll-casting.’ Polymer solutions were rolled between two corotating eccentric cylinders while at the same time the solvent was removed at a controlled rate. As the solvent evaporated, the block copolymers microphase separated into globally oriented structures. A discussion of the flow field that develops during roll-casting is presented and specific attention is given to the importance of the shear and elongation rates present. For the triblock and diblock, respectively, the processed structures consisted of polystyrene cylinders assembled on a hexagonal lattice in a polybutadiene matrix, and unidirectional lamellae of alternating polystyrene and polyethylene/propylene. Small-angle x-ray scattering (SAXS) and transmission electron microscopy (TEM) indicated the near single-crystal structure both types of films. SAXS also showed the styrene cylinders and the alternating lamellae to be packed closer together in roll-cast films than in simple quiescently cast films. A molecular orientation mechanism is proposed to describe both these results as well as the changes in packing and in macroscopic sample dimensions measured after complete solvent evaporation and after sample annealing. © 1993 John Wiley & Sons, Inc.     

Roll-Casting of block copolymers and of block copolymer-homopolymer blends

An improved technique for casting highly oriented films of block copolymers from solutions subjected to flow is presented. Polymer solutions were rolled between two counter-rotating adjacent cylinders while at the same time the solvent was allowed to evaporate. As the solvent evaporated, the block copolymers microphase separated into globally oriented structures. Using this method known as ‘roll-casting’ we present in this paper a study of the morphology of polystyrene-polybutadiene-polystyrene (PS/PB/PS) triblock copolymer cast with and without additional high molecular weight homopolymers. The pure copolymer films consisted of polystyrene cylinders assembled on a hexagonal lattice in a polybutadiene matrix in a near single-crystal structure. Blends of copolymer with high molecular weight polystyrene and/or polybutadiene, phase separated into ellipsoidal regions of homopolymer embedded in an oriented block copolymer matrix. Annealing the films resulted in conversion of the homopolymer regions to spheres accompanied by some misalignment of the copolymer microdomains. The morphology of these films as revealed by TEM is discussed. A brief discussion of the flow field that develops in the experimental system is also presented and its similarity to the flow field of our previous work is shown. © 1994 John Wiley & Sons, Inc.     

A novel image fusion method using WBCT and PCA

A novel image fusion algorithm based on wavelet-based contourlet transform （WBCT） and principal component analysis （PCA） is proposed. The PCA method is adopted for the low-frequency components. Using the proposed algorithm to choose the greater of the active measures, the region consistency test is performed for the high-frequency components. Experiments show that the proposed method works better in preserving the edge and texture information than wavelet transform method and Laplacian pyramid （LP） method do in image fusion. Four indicators for the fusion image are given to compare the proposed method with other methods.     

基于灰度共生矩阵的表面粗糙度研究

介绍了激光散斑的形成及其统计性质,拍摄大量不同加工工艺、不同表面粗糙度标准样块的散斑图像,基于激光散斑图像的灰度共生矩阵及惯性矩、角二阶矩、熵、相关性4个参量,对图像进行了纹理分析.分别绘制了不同加工工艺、不同表面粗糙度标准样块的4个参量与表面粗糙度关系的特性曲线.最后将实验结果和未知表面粗糙度工件的实验数据进行比对,准确估算出了工件的表面粗糙度.     

Side-chain cholesteric liquid-crystalline elastomers containing azobenzene derivative as cross-linking agent – synthesis and characterisation

The cholesteric polysiloxanes (PLQ series) were obtained by reacting cholesteric monomer and phenolic hydroxyl monomer in different ratios with polysiloxanes. The chiral azo-containing polysiloxanes liquid-crystalline elastomers (LCEs) were synthesised by esterifying PLQ series with acyl acid of azo diacid catalysed by 4-dimethylaminopyridine (DMAP). The chemical structures and mesomorphic properties of monomers and polymers were confirmed by conventional spectroscopic methods. The elastomers displayed elastic properties, reversible phase transition and high thermal stability. The T_g values changed irregularly and T_i values decreased at the beginning and then increased afterwards. The chiral azo-LCEs showed colourful textures and a Grandjean texture could be observed, which exhibited a red shift with increasing content of azo moiety. PLQ₂–PLQ₆ exhibited selective reflection in the visible light region, but PLZ₁–PLZ₄ can only observe selective reflection when appropriate mechanical pressure was imposed on the polymers. The PLZ series was carefully investigated by ultra violet–visible spectroscopy.     

Comparative study for the removal of methylene blue via adsorption and photocatalytic degradation

Physically and chemically activated carbons were prepared from date pits and olive stones. Titania and WO(x)-TiO(2)/MCM-41 were prepared as photoactive catalysts. Surface characterizations were investigated from ash content, pH, base neutralization capacities and FT-IR techniques. The textural characteristics, namely specific surface area (S(BET)) and pore texture, were determined from low temperature adsorption of N(2) at 77 K. The decolorization of aqueous solution of methylene blue was performed by means of two alternative methods. Steam-activated carbons own higher surface area compared with ZnCl(2)-activated carbons, and the micropore surface area represents the major contribution of the total area. Steam-activated carbons were the most efficient decolorizing adsorbents owing to its higher surface area, total pore volume and the basic nature of the surface. The calculated values of DeltaG(0), DeltaH(0) and DeltaS(0) indicate the spontaneous behavior of adsorption. The photocatalytic degradation is more convenient method in decolorizing of methylene blue compared with the adsorption process onto activated carbons.     

纳米结构表面上部分润湿液滴合并诱导弹跳的理论研究

部分润湿液滴是适宜纳米结构表面上滴状冷凝传热的主要载体,研究纳米结构参数与部分润湿液滴合并弹跳之间的关系有重要意义,本文依据冷凝液滴生长过程中能量增加最小的原理来判断其是否为部分润湿状态,并根据液滴合并前后的体积和界面自由能守恒,确定了合并液滴的初始形状,进而对合并液滴变形过程的动力学方程进行了求解,结果表明:部分润湿冷凝液滴仅在纳米柱具有一定高度、直径间距比较大的表面上形成,而当纳米柱高度过低、直径间距比小于0.1时则形成完全润湿的冷凝液滴;液滴合并后能否弹跳与纳米结构参数紧密相关,仅在纳米柱较高、直径间距比适宜的表面上,部分润湿液滴合并后才能诱发弹跳;液滴尺度及待合并液滴间的尺度比对合并弹跳也有重要影响;多个部分润湿液滴合并后由于具有更多的过剩界面自由能而比两个液滴合并更容易诱发弹跳,本模型对纳米结构表面上冷凝液滴是否合并诱发弹跳的计算结果与绝大部分实测结果相一致,准确率达到95%。