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The multilamellar barrier materials based on the blends of high‐density polyethylene (HDPE) and copolyester (PETG) were prepared via melt extrusion, and poly(ethylene‐co‐acrylic acid) (EAA) as a compatibilizer was incorporated into the blends. A systematic investigation was carried out, with regard to morphology and properties. Scanning electron microscopy observation displayed the laminar morphology for the blends with the whole compositions, and the thinner laminas of the PETG phase formed in the HDPE matrix by incorporating EAA into the blends. In addition, the number and the size of the laminas of the dispersed phases were also dependant on the die temperature and screw speed, respectively. Evaluation of the mechanical properties demonstrated that incorporation of the EAA resulted in an improvement of the mechanical properties. These behaviors are attributed mainly to better adhesion and compatibility between HDPE and PETG, which has been confirmed by thermal analysis and the rheological properties. On the basis of these premises, it is reasonable to suggest that the improved barrier properties of the ternary blends with increasing concentration of the EAA be attributed to both the increase in the number of the laminas of the PETG and the decrease in their thickness, which prohibits the organic solvent molecules from entering into and permeating through the amorphous regions of the blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3791–3799, 2006 相似文献
93.
采用Gly—GlyOH,4,4'—联吡啶与Cu(NO_3)_2·H_2O在二次水溶液中反应,合成出以4,4'—bpy为中继基,Gly—Glyo为螯环新型双核铜配合物。经X射线单晶结构分析确定该配合物品体的化学结构式:[(H_2NCH_2CONHCH_2COO) Cu(OH) (C_(10)H_8N_2)Cu(OH) (H_2NCH_2CONHCH_2COO)]·9H_2O.晶体属于三斜晶系,P_空间群,晶胞参数a=1.1412nm,b=1.2298nm,C=1.4269nm,α=113.82°,β=101.91°,y=103.64°,V=1.6747nm~3,Z=2。衍射数据是在Nicolet XRD R3型四圆衍射仪上收集,结构参数经块矩阵最小二乘法精修后,最终一致性因子R值为0.068,RW值为0.057。 相似文献
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FLOCCULATION OF KAOLIN SUSPENSION OF ISOTACTIC-AND ATACTIC-POLY(N-PROPYL-2-VINYLPYRIDINIUM BROMIDE)
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Isotactic-and atactic-poly(N-propyl-2-vinylpyridinium bromide)QIP2VP and QAP2VP were used asflocculants for kaolin suspension.The effects of their molecular structure of floeculation were studied.Theresults are as follows:(1)The ability of flocculation of QAP2VP is better than that of QIP2VP.(2)The flocculating efficiency of QAP2VP,but not QIP2VP,increased as the molecular weight in-creased.(3)In the range of lower degree of quaternization,the efficiency of flocculation increased as thedegree of quaternization of flocculants decreased.(4)An abnormal phenomenon,which is considered as the“homocharge stabilization”,was discoveredat a certain concentration of flocculants.(5)An equation of the relationship among the experimental parametars,such as sedimentation rate,sedimentation volume and turbidity,was derived. 相似文献
96.
Expanded bed adsorption (EBA) is an integrative downstream processing technique for the purification of biological substances directly from unclarified feedstock. In this study, molecular chaperone GroEL, an important protein folding helper both in vivo and in vitro, was purified by the single-step EBA technique from the unclarified homogenate of recombinant E. coli cells. Compared with packed bed adsorption, the EBA technique provided a single-step approach to yield an electrophoretic purity of GroEL. After the homogenate loading and column washing in the expanded bed mode, the GroEL protein was recovered by stepwise salt-gradient elution in packed-bed or expanded-bed modes, respectively. The expanded-bed elution mode was found as efficient as the packed-bed mode in the purification of GroEL from cell disruptate. 相似文献
97.
基于GIS技术的农村非点源污染分析——以渠县境内巴河州河汇流断面上游区域为例 总被引:1,自引:0,他引:1
为了有效地分析巴河州河汇合口(渠县境内)以上流域非点源污染问题,应用GIS技术进行水文分析(水系提取、流域划分)以及污染源的空间分异分析。基于评估区的水环境污染现状,选取城镇居民生活污水、农村居民生活污水、城镇地表径流、集中式畜禽养殖、化肥污染五大污染源,采用源强系数法和输出系数法进行COD、TN、TP 3种污染物的流失量计算,并分析其污染负荷,。结果表明:(1)评估区的91.93%的负荷来源于为农村居民生活污水、化肥污染、和城镇居民生活污水,最主要的污染源为农村居民生活污水。(2)评估区重点治理乡镇为三汇镇。研究成果较为清晰地分析出研究区非点源污染的分布情况,指出了需要重点治理的地域和污染源。 相似文献
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Xiaodong Liu Shanshan Li Xiangke Liao Shaoliang Peng Lei Wang Zhiyin Kong 《World Wide Web》2014,17(4):627-647
Influence Maximization aims to find the top-K influential individuals to maximize the influence spread within a social network, which remains an important yet challenging problem. Most existing greedy algorithms mainly focus on computing the exact influence spread, leading to low computational efficiency and limiting their application to real-world social networks. While in this paper we show that through supervised sampling, we can efficiently estimate the influence spread at only negligible cost of precision, thus significantly reducing the execution time. Motivated by this, we propose ESMCE, a power-law exponent supervised Monte Carlo estimation method. In particular, ESMCE exploits the power-law exponent of the social network to guide the sampling, and employs multiple iterative steps to guarantee the estimation accuracy. Moreover, ESMCE shows excellent scalability and well suits large-scale social networks. Extensive experiments on six real-world social networks demonstrate that, compared with state-of-the-art greedy algorithms, ESMCE is able to achieve almost two orders of magnitude speedup in execution time with only negligible error (2.21 % on average) in influence spread. 相似文献