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71.
Algebras of fuzzy sets 总被引:2,自引:0,他引:2
In this paper we investigate two kinds of algebras of fuzzy sets, which are obtained by using Zadeh's extension principle. We give conditions under which a homomorphism between two algebras induces a homomorphism between corresponding algebras of fuzzy sets. We prove that if the structure of truth values is a complete residuated lattice, the induced algebra of a subalgebra of an algebra can be embedded into the induced algebra of fuzzy sets of . For direct products we give conditions under which the direct product of algebras of fuzzy sets could be embedded into the algebra of fuzzy sets of the direct product. In the case of homomorphisms and direct products, the two kinds of algebras of fuzzy sets behave in different ways. 相似文献
72.
73.
在效应代数中引入模糊滤子和模糊理想的概念,讨论了它们的性质;引入并研究了强模糊滤子;在全序效应代数中提出了一个模糊同余关系并证明了这样生成的同余类是一个全序格效应代数. 相似文献
74.
在[4]中,我们引入了Z-蕴含代数的概念,讨论了它们的一些性质.本文中,我们进一步引入Z-蕴含代数的Z-滤子,并研究它们一些有趣的结果. 相似文献
75.
分别采用电子轰击(EI)和正化学电离(PCI)两种离子源技术建立了气相色谱-质谱联用法(GC-MS)同时测定橄榄油中3,5-菜甾二烯、3,5,22-豆甾三烯和3,5-豆甾二烯3种甾醇烯含量的方法,并对这两种方法进行了比较。样品经石油醚溶解,硅胶柱净化后,分别采用GC-EI/MS和GC-PCI/MS分时段选择离子监测模式进行测定,以3,5-胆甾二烯为内标进行定量。结果表明,两种方法的线性、准确度、精密度、灵敏度均较好。3,5-菜甾二烯、3,5,22-豆甾三烯和3,5-豆甾二烯分别在0.024~0.48、0.02~0.50和0.03~0.75 mg/L浓度范围内线性关系良好(r>0.999)。在3个加标水平下,GC-EI/MS和GC-PCI/MS的平均回收率分别为88.7%~99.5%、87.1%~109.2%,两种检测方法的相对标准偏差(RSD,n=6)均不超过8.3%。定量限(S/N=10)分别为0.03 mg/kg(EI),0.03~0.10 mg/kg(PCI)。通过对两种方法的比较研究发现,EI能提供更多碎片离子和结构信息,而PCI中则主要为准分子离子及反应气加合离子。应用于样品中甾醇烯的测定时,PCI的选择性和抗干扰能力明显优于EI。两种方法可相互补充和替代应用于日常检测中。 相似文献
76.
Characterization of N‐methylated amino acids by GC‐MS after ethyl chloroformate derivatization
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B. Sudarshana Reddy V. Naresh Chary P. Pavankumar S. Prabhakar 《Journal of mass spectrometry : JMS》2016,51(8):638-650
Methylation is an essential metabolic process in the biological systems, and it is significant for several biological reactions in living organisms. Methylated compounds are known to be involved in most of the bodily functions, and some of them serve as biomarkers. Theoretically, all α‐amino acids can be methylated, and it is possible to encounter them in most animal/plant samples. But the analytical data, especially the mass spectral data, are available only for a few of the methylated amino acids. Thus, it is essential to generate mass spectral data and to develop mass spectrometry methods for the identification of all possible methylated amino acids for future metabolomic studies. In this study, all N‐methyl and N,N‐dimethyl amino acids were synthesized by the methylation of α‐amino acids and characterized by a GC‐MS method. The methylated amino acids were derivatized with ethyl chloroformate and analyzed by GC‐MS under EI and methane/CI conditions. The EI mass spectra of ethyl chloroformate derivatives of N‐methyl ( 1–18 ) and N,N‐dimethyl amino acids ( 19–35 ) showed abundant [M‐COOC2H5]+ ions. The fragment ions due to loss of C2H4, CO2, (CO2 + C2H4) from [M‐COOC2H5]+ were of structure indicative for 1–18 . The EI spectra of 19–35 showed less number of fragment ions when compared with those of 1–18 . The side chain group (R) caused specific fragment ions characteristic to its structure. The methane/CI spectra of the studied compounds showed [M + H]+ ions to substantiate their molecular weights. The detected EI fragment ions were characteristic of the structure that made easy identification of the studied compounds, including isomeric/isobaric compounds. Fragmentation patterns of the studied compounds ( 1–35 ) were confirmed by high‐resolution mass spectra data and further substantiated by the data obtained from 13C2‐labeled glycines and N‐ethoxycarbonyl methoxy esters. The method was applied to human plasma samples for the identification of amino acids and methylated amino acids. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
77.
In this paper, the SRS-induced crosstalk has been evaluated in a SCM–WDM communication links at different modulation frequencies and transmission lengths for variety of fiber. Results show that SRS-induced crosstalk dominates at low frequency. As the dispersion and effective area of fiber (Aeff) decreases, initially the crosstalk remains high and then it decreases with increase in modulation frequency. The present work shows that out of five different types of fiber, standard single mode fiber (SMF) has minimum crosstalk (−78 to −38) dB, (−55 to −33) dB and (−46 to −34) dB at modulation frequencies, transmission lengths and optical powers. Dispersion compensation fiber (DCF) has maximum crosstalk (−60 to −12) dB, (−37 to −12) dB and (−27 to −12) dB at modulation frequencies and transmission lengths. 相似文献
78.
《复变函数与椭圆型方程》2012,57(10):915-928
In this paper, we obtain Cauchy's integral formula on certain distinguished boundary for functions with values in a universal Clifford algebra, which is similar to the classical Cauchy's integral formula on the distinguished boundary of polycylinder for several complex variables. By using it, both the mean value theorem and the maximum modulus theorem are given. 相似文献
79.
叠加激发双模压缩真空态的量子统计特性(英文) 总被引:5,自引:3,他引:2
从激发双模压缩真空态a+mb+m|ξ>出发构造了叠加态|Ψ>,研究了|Ψ>的量子统计特性.结果表明:在一定的条件下,随着相位差的变化,叠加态|Ψ>的平均光子数出现类似于Rabi振荡的崩塌与复原现象,而且与单个激发双模压缩真空态a+mb+m|ξ>相比,在叠加态|Ψ>中光场的相位压缩和亚泊松光子统计特性都得到了加强. 相似文献
80.
The mass spectra of a series of N‐aryl α,β‐unsaturated γ‐lactams were studied. Besides the molecular ion, the three characteristic fragments such as [M+‐29], [M+‐55], and [M+‐82] were commonly found in a series of N‐Aryl α,β‐unsaturated γ‐lactams in EI/MS. Further more the mechanism for the interpretation of these fragments is also de scribed. 相似文献