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991.
Quantification of the layer dispersion degree in polymer layered silicate nanocomposites by transmission electron microscopy 总被引:1,自引:0,他引:1
As the performance of polymer layered silicate nanocomposites strongly depends on their interior layer dispersion, quantification of the layer dispersion degree is needed. In this work, a new methodology was developed to determine the dispersion parameter D0.1, based on the measurement of the free-path spacing distance between the single clay sheets from the transmission electron microscopy (TEM) images. Several examples of exfoliated, intercalated, and immiscible composites were studied. It was found that the exfoliated composites had D0.1 over 8%, while that of intercalated composites were between 4 and 8%. In the case of intercalation, a high frequency peak appeared at a short spacing distance in the histogram, which was a characteristic of the intercalation, distinct from the exfoliation. The main utility of this TEM methodology is for the quantification of exfoliated or intercalated samples with small number of layers with stacks. The dispersion parameter D0.1 below 4% was suggested to classify as immiscible. A unique advantage of the TEM measurement is that the dispersion degree of different fillers can be counted individually. 相似文献
992.
993.
Shaobing Zhou Qiuxiang Su Xiaohong Li Jie Weng 《Materials Science and Engineering: A》2006,430(1-2):341-345
In the paper, we found a novel method to synthesize dicalcium phosphate dehydrate (DCPD) nanocrystals by in situ reaction in biodegradable PDLLA matrix. Calcium hydrid was selected as calcium source of DCPD, which is different from general methods. The method is not only simple and effective to synthesize Ca–P particles, but also can avoid the aggregation of inorganic nanoparticles in the course of their being dispersed into polymer matrix. 相似文献
994.
995.
Y Nakamura Y Horii T Nishino H Shiiki Y Sakaguchi T Kagoshima K Dohi Z Makita H Vlassara R Bucala 《Canadian Metallurgical Quarterly》1993,143(6):1649-1656
Advanced glycosylation end products (AGEs) accumulate on long-lived extracellular matrix proteins and have been implicated in the micro- and macrovascular complications of diabetes mellitus. Within the arterial wall, AGE-modified proteins increase vascular permeability, inactivate nitric oxide activity, and induce the release of growth-promoting cytokines. Recently developed anti-AGE antibodies were used in an immunohistochemical analysis of coronary arteries obtained from type II diabetic and nondiabetic patients. High levels of AGE reactivity were observed within the atherosclerotic plaque present in vessels from selected patients with diabetes. Considered together with the pathological effects of AGEs on vascular wall homeostasis, these data support the role of advanced glycosylation in the rapidly progressive atherosclerosis associated with diabetes mellitus. 相似文献
996.
997.
998.
轻质高效保温材料掺杂硅气凝胶 总被引:3,自引:0,他引:3
利用正硅酸甲脂(TMOS)为原料的溶胶-凝胶过程,摸索了不同反应条件下形成凝胶的规律,并选用TiO2粉末及玻璃纤维作为掺杂剂,采用超临界干燥处理制备出掺TiO2的硅气凝胶,通过对红外光谱以及不同温度和气压条件下热导率的测量,讨论了不同成份配比以及相应的热传输过程对材料热导率的影响。结果表明,密度为260kg/m^3的掺杂硅气凝胶在800K时的热导率为0.038w/m.k,是一种新型的轻质高效保温材 相似文献
999.
介绍了光纤传输数字电视的意义,电视信号分量数字化的标准和优点。利用自行研制的270Mb/s光发射机和光接收机,建立了分量数字电视信号的光纤传输系统,直接传输了100km光纤,系统传输无误码,传输后图像质量不变。光接收机灵敏度达-29.24dBm,动态范围为13.5dB。无压缩电视图像的传输对于远程医疗和演播室间转输节目等有非常实际的意义。 相似文献
1000.