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71.
The effect of end groups (2NH2) of poly(ethylene glycol) (PEG) on the miscibility and crystallization behaviors of binary crystalline blends of PEG/poly(L ‐lactic acid) (PLLA) were investigated. The results of conductivity meter and dielectric analyzer (DEA) implied the existence of ions, which could be explained by the amine groups of PEG gaining the protons from the carboxylic acid groups of PLLA. The miscibility of PEG(2NH2)/PLLA blends was the best because of the ionic interaction as compared with PEG(2OH, 1OH‐1CH3, and 2CH3)/PLLA blends. Since the ionic interaction formed only at the chain ends of PEG(2NH2) and PLLA, unlike hydrogen bonds forming at various sites along the chains in the other PEG/PLLA blend systems, the folding of PLLA blended with PEG(2NH2) was affected in a different manner. Thus the fold surface free energy played an important role on the crystallization rate of PLLA for the PEG(2NH2)/PLLA blend system. PLLA had the least fold surface free energy and the fast crystallization rate in the PEG(2NH2)/PLLA blend system, among all the PEG/PLLA systems studied. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
72.
Published:// 《中国标准化(英文版)》2007,24(6):10-13
There are no explicit laws concerning food recalls in China; moreover, some related regulations have weaknesses. China should first create a system of laws and regulations governing food recalls, establish a system to recall defective food, and strengthen administrative and legal remedial mechanisms related to consumer rights. 相似文献
73.
Dynamic neural networks with different time-scales include the aspects of fast and slow phenomenons. Some applications require
that the equilibrium points of the designed networks are stable. In this paper, the passivity-based approach is used to derive
stability conditions for dynamic neural networks with different time-scales. Several stability properties, such as passivity,
asymptotic stability, input-to-state stability and bounded input bounded output stability, are guaranteed in certain senses.
A numerical example is also given to demonstrate the effectiveness of the theoretical results. 相似文献
74.
75.
Wenying Wei Zhen Wang Yanhua Yin Jinyu Han Wen Xu 《Korean Journal of Chemical Engineering》2008,25(3):562-567
Composition Group Vector Space (CGVS) method for estimating melting and boiling point T
m
, T
b
of organic compound has been proposed, and the principle of this method has been elucidated. The models for estimating T
m
, T
b
have been established and the numerical values of relative parameters have been presented. The average percentage deviations
of T
m
, T
b
estimation are 7.53 and 1.58, respectively, which show that the present method demonstrates significant improvement in applicability
to predict the above properties, compared to conventional group methods. 相似文献
76.
本文首次报道胨冻样芽孢杆菌XDB1和D4B1对烟草灰霉病菌(Botrytis cinerea)的抑制作用。实验表明,XDB1和D4B1的发酵原液和无细胞提取物具有相同的抑菌效果,而经121℃处理30分钟后,抑菌活性丧失。D481菌株的抑菌活性高于XDB1,钾长石作为基质时的活性高于土壤矿物。但是,XDB1和D481对立枯丝核病菌(R..solani)、西瓜尖孢镰刀菌(F.oxysporum)、腐霉(Pythium sp)、小麦全蚀病菌(G.graminis)、烟炭疽病菌(C.gloeosporides)、烟草赤星病菌(A.alternata)、烟草黑胫病菌(P.nicotianae、串珠镰刀病菌(F.moniliforme)和水稻稻瘟病菌(P.grisea)无抑制作用。 相似文献
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