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41.
态射的广义Moore—Penrose逆 总被引:22,自引:4,他引:22
本文定义了态射的广义Moore-Penrose逆,给出了它存在的一些充要条件,确定了它的一些表达式,推广了关于态射的Moore-Penrose逆的相应结果。 相似文献
42.
The main objective of this study was to evaluate the sound absorption properties of rigid polyurethane foams (PUFs) produced from crude glycerol (CG) and/or liquefied coffee grounds derived polyol (POL). The lignin content of POL proved to have a major influence on the structure and mechanical properties of the foams. Indeed, the POL content increased the cell size of the foams and their stiffness, which subsequently influenced the sound absorption coefficients. The POL derived foam has slightly higher sound absorption coefficient values at lower frequencies, while the CG foam has higher sound absorption coefficient values at higher frequencies. In turn, the foam prepared using a 50/50 mixture of polyols presents slightly higher sound absorption coefficient values in the medium frequencies range due to a balance between the cell structure and the mechanical properties. The results obtained seem to suggest that the mechanisms involved in sound wave absorption depend on the formulation used to prepare the foams. Additionally higher POL contents improved the thermal stability of PUFs as well as their mechanical properties. From this work the suitability of CG and/or POL derived PUFs as sound absorbing materials has been proven. 相似文献
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44.
Michael P. Drazin 《代数通讯》2020,48(4):1423-1438
45.
Esmaeil Hosseini 《代数通讯》2019,47(9):3781-3788
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47.
以L~*-格值上Lukasiewicz蕴含算子为工具引入了直觉I-Fuzzy拓扑空间中导集概念,接着给出它的一些性质,最后证明了直觉I-Fuzzy拓扑空间中导集的杨忠道定理. 相似文献
48.
Age K. Smilde Marieke E. Timmerman Edoardo Saccenti Jeroen J. Jansen Huub C. J. Hoefsloot 《Journal of Chemometrics》2015,29(5):277-288
In modern omics research, it is more rule than exception that multiple data sets are collected in a study pertaining to the same biological organism. In such cases, it is worthwhile to analyze all data tables simultaneously to arrive at global information of the biological system. This is the area of data fusion or multi‐set analysis, which is a lively research topic in chemometrics, bioinformatics, and biostatistics. Most methods of analyzing such complex data focus on group means, treatment effects, or time courses. There is also information present in the covariances among variables within a group, because this relates directly to individual differences, heterogeneity of responses, and changes of regulation in the biological system. We present a framework for analyzing covariance matrices and a new method that fits nicely in this framework. This new method is based on combining covariance prototypes using simultaneous components and is, therefore, coined Covariances Simultaneous Component Analysis (COVSCA). We present the framework and our new method in mathematical terms, thereby explaining the (dis)similarities of the methods. Systems biology models based on differential equations illustrate the type of variation generated in real‐life biological systems and how this type of variation can be modeled within the framework and with COVSCA. The method is subsequently applied to two real‐life data sets from human and plant metabolomics studies showing biologically meaningful results. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
49.
Yongqiang Zhang ShengzhengWang Zhenyuan Miao Jianzhong Yao Wannian Zhang Chunquan Sheng 《中国化学》2013,(9):1139-1143
Iodiconazole is a novel antifungal agent that was developed in its racemic form. In order to investigate the ef- fects of the chiral center on the antifungal activity, R- and S-isomers of iodiconazole were prepared on the basis of the asymmetric Sharpless epoxidation. (S)-Iodiconazole was proved to have better antifungal activity than the (R)- isomer. The binding modes of the two isomers with lanosterol 14~z-demethylase were clarified by molecular dock- ing. 相似文献
50.
重度原油注空气低温氧化过程研究(英文) 总被引:1,自引:0,他引:1
低温氧化反应对现场燃烧(ISC)技术点火的成功有十分重要的影响.采用高压氧化管,研究了不同温度压力下,新疆克拉玛依重度原油的低温氧化过程.结果表明,温度和压力的变化对低温氧化反应的放热程度、持续时间以及气体产物有明显影响.适合油样低温氧化反应的温度和压力分别为150℃和10MPa.此外,采用纯组分替代原油族组分进行低温氧化实验,研究低温氧化反应对原油族组分(饱和烃、芳香烃、胶质、沥青质)含量的影响.结果表明,原油所含族组分中,芳香烃组分最易被氧化,其含量由氧化前的19.17%减少到12.38%(150℃)和9.51%(250℃).随着低温氧化过程的进行,结构复杂的族组分(胶质、沥青质)的含量明显增加.实验数据对油藏实施注空气技术,以及该技术现场实施条件的确定有十分重要的指导意义. 相似文献