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991.
Flow injection (FI) was coupled to ion-pair reversed phase high performance liquid chromatography (IP-RPHPLC) for the simultaneous analysis of some metal-4-(2-pyridylazo) resorcinol (PAR) chelates. A simple reverse flow injection (rFI) set-up was used for in-line complexation of metal-PAR chelates prior to their separation by IP-RPHPLC. The rFI conditions were: injection volume of PAR 85 μL, flow rate of metal stream 4.5 mL min−1, concentration of PAR 1.8 × 10−4 mol L−1 and the mixing coil length of 150 cm. IP-RPHPLC was carried out using a C18 μBondapak column with the mobile phase containing 37% acetonitrile, 3.0 mmol L−1 acetate buffer pH 6.0 and 6.2 mmol L−1 tetrabutylammonium bromide (TBABr) at a flow rate of 1.0 mL min−1 and visible detection at 530 and 440 nm. The analysis cycle including in-line complexation and separation by IP-RPHPLC was 16 min, which able to separate Cr(VI) and the PAR chelates of Co(II), Ni(II) and Cu(II). 相似文献
992.
Analysis of stable and radioactive isotopes from bone collagen provides useful information to archaeologists about the origin and age of bone artifacts. Isolation and analysis of single amino acids from the proteins can provide additional and more accurate information by removing contamination and separating a bulk isotope signal into its constituent parts. In this paper, we report a new method for the separation and isolation of underivatized amino acids from bone collagen, and their analysis by isotope ratio MS and accelerator MS. RP chromatography is used to separate the amino acids with nonpolar side chains, followed by an ion pair separation to isolate the remaining amino acids. The method produces single amino acids with little or no contamination from the separation process and allows for the measurement of accurate stable isotope ratios and pure samples for radiocarbon dating. 相似文献
993.
Francesco Caravenna Giambattista Giacomin Massimiliano Gubinelli 《Journal of statistical physics》2006,122(4):799-832
We consider a model of a random copolymer at a selective interface which undergoes a localization/delocalization transition. In spite of the several rigorous results available for this model,
the theoretical characterization of the phase transition has remained elusive and there is still no agreement about several
important issues, for example the behavior of the polymer near the phase transition line. From a rigorous viewpoint non coinciding
upper and lower bounds on the critical line are known.
In this paper we combine numerical computations with rigorous arguments to get to a better understanding of the phase diagram.
Our main results include:
2000 MSC: 60K37, 82B44, 82B80 相似文献
– | Various numerical observations that suggest that the critical line lies strictly in between the two bounds. |
– | A rigorous statistical test based on concentration inequalities and super–additivity, for determining whether a given point of the phase diagram is in the localized phase. This is applied in particular to show that, with a very low level of error, the lower bound does not coincide with the critical line. |
– | An analysis of the precise asymptotic behavior of the partition function in the delocalized phase, with particular attention to the effect of rare atypical stretches in the disorder sequence and on whether or not in the delocalized regime the polymer path has a Brownian scaling. |
– | A new proof of the lower bound on the critical line. This proof relies on a characterization of the localized regime which is more appealing for interpreting the numerical data. |
994.
《Discrete Mathematics》2020,343(3):111762
We introduce a variant of the Kronecker product, called the regional Kronecker product, that can be used to build new, larger multiple-pair latin squares from existing multiple-pair latin squares. We present applications to the existence and orthogonality of multiple-pair latin squares. 相似文献
995.
New classes of mappings, called cyclic (noncyclic) condensing operators, are introduced and used to investigate the existence of best proximity points (best proximity pairs) with the help of a suitable measure of noncompactness. In this way, we obtain some real generalizations of Schauder and Darbo’s fixed point theorems. In the last section, we apply such results to study the existence of optimum solutions to a system of differential equations. 相似文献
996.
LI JianLin College of Mathematics Information Science Shaanxi Normal University Xi'an China 《中国科学 数学(英文版)》2010,(5)
Spectra and tilings play an important role in analysis and geometry respectively.The relations between spectra and tilings have bafied the mathematicians for a long time.Many conjectures,such as the Fuglede conjecture,are placed on the establishment of relations between spectra and tilings,although there are no desired results.In the present paper we derive some characteristic properties of spectra and tilings which highlight certain duality properties between them. 相似文献
997.
In this paper we introduce the notion of (f,ω)-compatible pair (B,H), by which we construct a Hopf algebra in the category HHYD of Yetter-Drinfeld H-modules by twisting the comultiplication of B. We also study the property of ω-smash coproduct Hopf algebras Bω H. 相似文献
998.
For the module category of a hereditary ring, the Ext-orthogonal pairs of subcategories are studied. For each Ext-orthogonal pair that is generated by a single module, a 5-term exact sequence is constructed. The pairs of finite type are characterized and two consequences for the class of hereditary rings are established: homological epimorphisms and universal localizations coincide, and the telescope conjecture for the derived category holds true. However, we present examples showing that neither of these two statements is true in general for rings of global dimension 2. 相似文献
999.
构建社会主义新农村建设的评价指标体系的集对分析模型,是指在综合分析的基础上,基于一定的原则和标准,对新农村建设的进程做出定量评价.建立起一套客观、合理、操作简便的评价指标体系,利用现代的数学方法建立定量评价模型. 相似文献
1000.
如何合理确定综合评价函数是系统分析评价中的关键问题.目前,所采用的方法是单纯从"数学变换"的角度建立综合评价函数,没有考虑研究对象的实际含义.因此,探讨不同的综合评价函数方法具有重要意义.根据综合评价对象的实际含义,定义了联系函数的概念,在此基础上,通过对研究对象进行两次集对同异反分析,建立基于联系函数的系统综合评价模型.实例分析表明:基于联系函数的系统综合评价模型评价结果准确、合理、可信,具有推广应用价值. 相似文献