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131.
High solid content latex: Preparation methods and application 总被引:2,自引:0,他引:2
One of the major challenges in emulsion polymerization over the past two decades was how to increase the solid content of latex products. In contrast to the conventional latex, high solid content (HSC) latex has a large volume fraction of dispersed phase, even larger than 70% in weight. Conventional emulsion polymerization, miniemulsion polymerization, self-emulsification polymerization and concentrated emulsion polymerization were all used to prepare HSC latexes, and many good results have been reported in recent years. Meanwhile, many applications of HSC latexes have also been developed. The present review summarized the progresses in the past few years mainly on the preparation methods and application of HSC latexes. Finally, some research directions as well as prospects were also proposed. 相似文献
132.
Forsythia suspensa (Thunb.) Vahl is one of the most widely used traditional Chinese medicines, and possesses important biological activities, such as antibacterial, antiviral, anti-inflammatory and antioxidant activities. Phillyrin is the main bioactive component of Forsythia suspensa. In this paper, ultrasound-assisted extraction of phillyrin from Forsythia suspensa was studied with HPLC-photodiode array detection. Effects of several experimental parameters, such as type and concentration of extracting solvent, ratio of liquid to material, extraction temperature, and time of sonication on extraction efficiencies of phillyrin from Forsythia suspensa were evaluated. The optimal extraction conditions were 1g plant sample with 10 ml of 20% methanol and the extraction for 60 min at 60°C under ultrasonic irradiation. Under the optimum conditions, the yield of phillyrin was 0.713±0.009 mg/g. The results indicated that the ultrasound-assisted extraction is a very useful method for the extraction of important phytochemicals from plant materials. 相似文献
133.
The formation of macrostep during high-temperature phase of barium meta-borate (α-BaB 2 O 4) single crystal growth has been investigated by both optical in-situ observation system and atomic force microscopy (AFM).The insitu observation results demonstrate that the critical linear size of growing facet exceeding the size that the macrostep generates is significantly anisotropic.The critical linear sizes are around 280 μm and 620 μm for {1010} and {1010} planes,respectively.AFM study illustrates that macrostep train with a height of 150 nm~200 nm is one typical morphological feature of the as-grown crystal surface.The riser of each macrostep consists of several straight and parallel sub-steps,indicating the occurrence of step bunching.Additionally,triangular sub-steps with heights of several nanometers on the treads of the macrosteps are found to be another typical feature of surface morphology,which implies a microscopically competitive bunching of sub-steps between various crystallographic orientations. 相似文献
134.
采用化学镀和黏接法制备层状磁电复合材料Ni/PZT/TbFe2,研究其磁电性能及谐振频率随Ni层厚度的变化情况. 结果表明:Ni/PZT/TbFe2层状磁电复合材料与其他结构的磁电性能不同,其一阶弯曲谐振峰值和纵向谐振峰值都很大. 随着Ni层厚度的增加,Ni/PZT/TbFe2层状磁电复合材料的一阶纵向谐振峰值逐渐增大. 结合实验数据和理论计算值得出了材料的一阶弯曲谐振频率fr1和一阶纵向谐振频率f
关键词:
磁电效应
正磁致伸缩
负磁致伸缩
谐振频率 相似文献
135.
136.
We prove that the regularity of a vertex operator superalgebra can be reduced to the semisimplicity of the category of its weak modules.Moreover,the rationality can be replaced by requiring that each 1/2Z+-graded module is a direct sum of irreducible weak modules. 相似文献
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139.
研究了5种α,α‘-二氧代烯酮环二硫代缩酮类化合物的碳基、碳碳双键、碳硫等一些特征红外光谱,尤其着重研究了共轭体系下的各种特征谱带随化学结构而变化的规律。 相似文献
140.
Stephen G. Davies Ai M. Fletcher Gesine J. Hermann Giovanna Poce Paul M. Roberts Andrew D. Smith Miles J. Sweet James E. Thomson 《Tetrahedron: Asymmetry》2010,21(13-14):1635-1648
The doubly diastereoselective conjugate addition of the antipodes of lithium N-benzyl-N-(α-methylbenzyl)amide to a range of enantiopure N-enoyl oxazolidin-2-ones has been used as a mechanistic probe to determine that the reactive conformation is the anti-s-cis form. The β-amino carbonyl products resulting from these conjugate addition reactions are useful templates for further elaboration into an α,β,α-pseudotripeptide. 相似文献