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排序方式: 共有2298条查询结果,搜索用时 125 毫秒
81.
82.
通过扫描电镜(SEM)观察了水辅助注塑聚丙烯(PP)/乙烯-醋酸乙烯共聚物(EVA)共混物制品近浇口和远浇口处外表层、芯层和内表层的相形态.结果表明,分散相主要以层状分布在基体中,在两个观察位置外表层和内表层的层状分散相厚度比芯层的大,远浇口处外表层和内表层的分散相厚度比近浇口处对应层的大.从温度场和剪切场两个方面分析了分散相的形变过程. 相似文献
83.
Long-term atmospheric corrosion of mild steel 总被引:3,自引:0,他引:3
A great deal of information is available on the atmospheric corrosion of mild steel in the short, mid and even long term, but studies of the structure and morphology of corrosion layers are less abundant and generally deal with those formed in just a few years. The present study assesses the structure and morphology of corrosion product layers formed on mild steel after 13 years of exposure in five Spanish atmospheres of different types: rural, urban, industrial and marine (mild and severe). The corrosion layers have been characterised by X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Long-term corrosion is seen to be more severe in the industrial and marine atmospheres, and less so in the rural and urban atmospheres. In all cases the corrosion rate is seen to decrease with exposure time, stabilising after the first 4–6 years of exposure. The most relevant aspects to be noted are (a) the great compaction of the rust layers formed in the rural and urban atmospheres, (b) the formation of hematite and ferrihydrite phases (not commonly found) in the industrial and marine atmospheres, respectively and (c) identification of the typical morphological structures of lepidocrocite (sandy crystals and flowery plates), goethite (cotton balls structures) and akaganeite (cotton balls structures and cigar-shaped crystals). 相似文献
84.
Yuling YangXueming Li Wenlin Feng Wenjin YangWulin Li Chuanyi Tao 《Journal of Alloys and Compounds》2011,509(3):845-848
Using polyethylene glycol (PEG), Tween-80, sodium dodecyl sulphonate (SAS) and cetyltrimethylammonium bromide (CTAB) as surfactants, CaMoO4: Eu3+ red phosphors were prepared by co-precipitation method and their morphology, structure and luminescent properties were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and fluorescence spectrometer. The results showed that the introduction of surfactants did not change the crystal structure of CaMoO4: Eu3+ phosphors, but greatly influenced their morphology. CaMoO4: Eu3+ red phosphors were prepared with 5 wt% PEG20000 having small-sized and regularly spherical morphology, and there were greater improvement in the luminescent intensity than phosphors prepared with other surfactants. 相似文献
85.
Multifunctional thermoplastic main-chain benzoxazine prepolymers were synthesized and systematically varied in their structure in order to function as high-performance toughener additives. Their unique chemical composition allows multiple covalent crosslinking with many thermoset network systems including benzoxazines and epoxides in conjunction with a defined chemical induced phase separation (CIPS) upon curing. This was successfully shown using a benzoxazine-based thermoset resin matrix as an example. The corresponding morphologies were addressable in a predictable manner and brought into context with the obtained macroscopic mechanical and thermal properties. In this relationship the CIPS process was classified and compared with the literature in more general means for advanced morphology control by differentiating between covalently attached and so-called gradient domain structures. The prepolymers were characterized by 1H NMR, FT-IR, DSC and TGA. The thermoset morphologies were investigated by TEM and AFM. The fracture toughness (KIc) and the elastic modulus (E) were measured by fracture and three point bending experiments. Thermal properties of the resulting films have been tested by DMA. 相似文献
86.
87.
Food packaging based on polymer nanomaterials 总被引:6,自引:0,他引:6
Clara Silvestre Donatella Duraccio Sossio Cimmino 《Progress in Polymer Science》2011,36(12):1766-1782
Since its starting in the 19th century, modern food packaging has made great advances as results of global trends and consumer preferences. These advances are oriented to obtain improved food quality and safety. Moreover, with the move toward globalization, food packaging requires also longer shelf life, along with the monitoring of safety and quality based upon international standards. Nanotechnology can address all these requirements and extend and implement the principal packaging functions - containment, protection and preservation, marketing and communications. Applications of polymer nanotechnology in fact can provide new food packaging materials with improved mechanical, barrier and antimicrobial properties, together with nano-sensors for tracing and monitoring the condition of food during transport and storage.The latest innovations in food packaging, using improved, active and smart nanotechnology will be analyzed. It will be also discuss the limits to the development of the new polymer nanomaterials that have the potential to completely transform the food packaging industry. 相似文献
88.
Kapoor SinghAmit Kumar Ritu Srivastava Partap S. KadyanModeeparampil N. Kamalasanan Ishwar Singh 《Optical Materials》2011,34(1):221-227
Bis(5,7-dimethyl-8-hydroxyquinolinato)zinc(II) (Me2q)2Zn and 5,7-dimethyl-8-hydroxyquinolinato(2-(2-pyridyl)benzimidazole) zinc(II) Me2q(pbi)Zn have been synthesized and characterized by various techniques. These metal complexes have high thermal stability (>300 °C) and high glass transition temperatures (>150 °C). The vacuum deposited films of these materials show good film forming property and are suitable for opto-electronic applications. Multilayered organic electroluminescent (EL) devices have been fabricated having structure ITO/α-NPD/zinc complex/BCP/Alq3/LiF/Al, which produce emission with chromaticity having Commission Internationale d’Eclairage (CIE) coordinates x = 0.506 and y = 0.484 for (Me2q)2Zn; x = 0.47 and y = 0.52 for (Me2q)(pbi)Zn complex. The electroluminescence spectra show peak emission centered at 572 and 561 nm respectively for these materials. 相似文献
89.
Salima Alem Ta-Ya Chu Shing C. Tse Salem Wakim Jianping Lu Raluca Movileanu Ye Tao Francis Bélanger Denis Désilets Serge Beaupré Mario Leclerc Sheila Rodman David Waller Russell Gaudiana 《Organic Electronics》2011,12(11):1788-1793
We investigated the effect of solvents on the morphology, charge transport and device performance of poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) and [6,6]-phenyl C71-butyric acid methyl ester (PC70BM) based solar cells. To carry out this investigation, chloroform and 1,2-dichlorobenzene were chosen as good solvents of the two compounds. Films prepared with chloroform exhibit larger domains than those prepared with 1,2-dichlorobenzene and their size increases with the amount of PC70BM. Fine tuning of the domain size was realized by using a solvent of mixed chloroform and 1,2-dichlorobenzene. At a mixing ratio of 50%:50%, a power conversion efficiency of 6.1% was achieved on PCDTBT:PC70BM (1:3) devices with an active area of 1 cm2, under air mass 1.5 global (AM 1.5 G) irradiation at 100 mW/cm2. 相似文献
90.
HSV空间和形态学处理相结合的车牌定位方法 总被引:1,自引:1,他引:0
车牌定位是实现车牌自动识别的前提.在传统的基于RGB彩色空间的形态学定位方法的基础上进行改进,提出了一种HSV彩色空间和图像形态学处理相结合的车牌定位方法.在HSV彩色空间中将车牌图像分割为H,S,V这3个单通道灰度图像,分别进行去噪和二值化处理,然后将这3幅二值图像做“与”运算得到一幅能有效去除背景干扰的二值图像,再运用形态学的闭运算和开运算进行处理,得到车牌候选区域,最后利用车牌宽高比属性进行验证以确定真实的车牌位置.实验结果表明,该方法相对传统方法实现简单,车牌定位准确、高效. 相似文献