NUMERICAL SIMULATION OF MORPHOLOGY OF POLYMER CHAIN COILS IN COMPLEX FLOWS

A new coupled finite element formulation is proposed to calculate a conformation tensor model in two complex flows： a planar contraction flow and a planar flow around a symmetrically placed cylinder. The components of conformation tensor are first computed together with the velocity and pressure to describe the change of morphology of polymer chain coils in flow fields. Macroscopic quantities of viscoelastic flow are then calculated based on the conformation tensor. Comparisons between the numerical simulations and experiments for stress patterns and velocity profiles are carried out to prove the validity of the method.     

THE EFFECT OF CLAY DISPERSION ON THE CRYSTALLIZATION AND MORPHOLOGY OF POLYPROPYLENE／CLAY COMPOSITES

PP/clay composites with different dispersions, namely, exfoliated dispersion, intercalated dispersion and agglomerates and particle-like dispersion, were prepared by direct melt intercalation or compounding. The effect of clay dispersion on the crystallization and morphology of PP was investigated via PLM, SAXS and DSC. Experimental results show that exfoliated clay layers are much more efficient than intercalated clay and agglomerates of clay in serving as nucleation agent due to the nano-scale dispersion of clay, resulting in a dramatic decrease in crystal size (lamellar thickness and spherulites) and an increase of crystallization temperature and crystallization rate. On the other hand, a decrease of melting temperature and crystallinity was also observed in PP/clay composites with exfoliated dispersion, due to the strong interaction between PP and clay. Compared with exfoliated clay layers, the intercalated clay layers have a less important effect on the crystallization and crystal morphology. No effect is seen for samples with agglomerates and particle-like dispersion, in regard to melting temperature, crystallization temperature, crystal thickness and crystallinity.     

Sphere-to-rod transition of short-chain PEO-b-PDMS-b-PEO in aqueous solution induced by copolymer concentration

A short-chain triblock copolymer EO9-DMS7-EO9 was synthesized by coupling reaction of allyl-terminated poly（ethylene oxide） and Si-H-terminated poly（dimethylsiloxane）. The structure and purity of synthesized copolymer was carefully characterized. Self-assembly behavior of EO9-DMST-EO9 triblock copolymer in water was investigated. And it was found that along with the increase of copolymer concentration, morphology of self-assembled aggregates transits from sphere to rod. A plausible understanding of the morphology transition for the investigated triblock copolymer was proposed.     

基于小波变换和数学形态学的孔径测量研究

针对视觉测量中硬盘圆孔孔径容易受到圆孔周围局部强反射、外部噪声的影响和测量精度不高的问题,提出一种基于小波变换、数学形态学和机器视觉相结合的圆形零件孔径测量方法。对摄像头采集圆孔图片,通过小波变换分解出高低频图像,利用小波变换对高频部分进行边缘提取,数学形态学对低频部分进行边缘提取,然后进行小波边缘融合,获取有效的圆孔边缘。利用最小二乘法对边缘进行孔径尺寸计算,经实验验证,该算法与其他算法相比,在有效地保留圆孔周围边缘信息的情况下,对周围噪声进行了有效的抑制,检测精度为0.01 mm以内,实验结果表明此方法简单易行,且具有较高的精度。     

航拍图像的路面裂缝识别EI北大核心CSCD

针对航拍沥青路面图像识别的噪声和干扰问题,提出一种应用于航拍图像的路面裂缝识别算法。根据路面区域与路旁景观区域灰度级数分布不同,采用多方向拟合的区域生长方法联合HSV颜色空间阈值进行路面区域分割,提取包含完整裂缝信息的单通道路面;再通过改进的形态学滤波剔除面积较大的干扰区域,利用结合显著性分析的边缘检测算法识别路面的裂缝片段,实现复杂裂缝与路面纹理噪声的区分;自动筛选存在裂缝的图像,针对裂缝可疑区域,结合人眼辅助观察标记并计算其长度。结果表明,该算法可有效剔除图像中的噪声和干扰,较好地识别沥青路面的裂缝,裂缝宽度的识别精度能达到9.7mm,分类识别准确率大于80.0%,长度测量准确率大于75.0%。     

In situ Coordination and Surface Morphology of Langmuir Films of Non－amphiphilic Dithizone with Metal Ions on Air／Water Interface

A spread Langmuir film on the air/water in-terface can serve as a basic model for the under-standing of organized molecular systems[1] .Gener-ally,it is considered that only those compoundsthat possess simultaneously a hydrophilic headgroup and a long- alkyl chain can be spread on theair/water interface[2— 4] .Therefore,researches onthe organized molecular films are mainly concernedwith typical amphiphiles.In order to expand thechoice in molecular film to form materials and omitthe tedious sy…     

浙江产索氏桃花水母的形态学及参数分析

对采自杭州和绍兴的桃花水母进行形态学特征的观察和鉴定,标本的形态学鉴别特征为：触手分3级,主辐触手明显较其它触手长;刺丝囊疣乳突状,围绕触手呈螺旋形排列;平衡囊管状,生殖腺为长囊状．其形态鉴别特征与文献报道的索氏桃花水母的分类特征一致,故将杭州与绍兴产桃花水母订为索氏桃花水母．对杭州产索氏桃花水母的形态特征系统地进行数量统计与分析,发现水母伞径与缘膜宽度、平衡囊数和触手数之间均呈显著或极显著的线性正相关关系,而平衡囊数与触手数之间的相关性不显著;性别对桃花水母伞径大小与缘膜宽度无显著性影响．     

Effects of AlN Layer and Impurities on Optical Properties of GaN

The effects of the incorporated oxygen and the different buffer layers on the optical properties and surface morphology of GaN were studied. The results show that the decrease of the concentration of the incorporated oxygen has no effect on the surface morphology, but improves the optical properties. While the introduction of the AIN buffer layer makes not only the surface morphology but also the optical properties improve. Both the oxygen contamination from the nitrogen source and the resulted morphology are directly related to the line width of the low-temperature photoluminescence(PL) spectra.     

逻辑函数形态学算子用于光学二元图像处理

提出了用于二元图像处理的逻辑函数形态学的概念。在逻辑函数形态学中,认为图像和结构核是逻辑函数,用１６个逻辑算子替代图像和结构之间在相关运算中的“乘积”,共得到１２个逻辑函数形态学算子。描述了逻辑形态学的光学实现,同时给出了实验结果。     

Characterizations of Skeletal Iron Catalysts Prepared from Rapidly and Naturally Quenched Fe-Al Alloys

Surface morphology, physical-chemical properties of skeletal iron catalysts prepared by leaching of the rapidly quenched(RQ) and naturally quenched(NQ) Fe-Al alloys with an aqueous solution of NaOH were characterized by using a series of techniques including XRD, BET, XPS, SEM, Hz and CO-TPD. It was found that the RQ skeletal iron catalyst exhibits a smaller particle size, larger specific surface area and pore volume than the NQ one. The H2 and CO-TPD experiments showed that the RQ skeletal iron exhibits stronger affinity for H2 and milder affinity for CO compared with the NQ one. But the NQ skeletal catalyst shows a better thermal stability than the RQ catalyst.