Thermal aqueous liquid chromatography—the TALC technique

Thermal Aqueous Liquid Chromatography (TALC) using pure water as a mobile phase should be a very attractive technique promoting the use of liquid chromatography in routine analysis, either in the laboratory or in future on-line process control. This simple form of chromatography, the selectivity of which depends on the fixed phase only, would allow the use of flame ionization as an almost universal, low-cost detector in liquid chromatography. The potential of the TALC technique is illustrated by selected examples.     

Nearest q-Flat to m Points

Recently, Bradley and Mangasarian studied the problem of finding the nearest plane to m given points in ⁿ in the least square sense. They showed that the problem reduces to finding the least eigenvalue and associated eigenvector of a certain n×n symmetric positive-semidefinite matrix. We extend this result to the general problem of finding the nearest q-flat to m points, with 0qn–1.     

修理延迟的设备修如旧模型的可用度

本文通过将使用时间在可能发生故障的时刻划分成时间区间,对修如旧模型下的多部件系统,在修理延迟条件下,对各类故障在同一时间区间里相容的条件下导出了任意给定时刻设备的可用度函数,并对文[3]中的算法做了改进,得到了更精确更合理的结果     

Hyperfine Field in Ferromagnetic CoPd Alloys

The magnetic hyperfine interaction of ⁶⁰Co in the completely miscible alloy Co _x Pd_1−x was investigated for different values of x by measuring the nuclear orientation of ⁶⁰Co as function of temperature and by nuclear magnetic resonance of the oriented ⁶⁰Co nuclei. A broad resonance signal of Gaussian shape could be observed down to x=60%. The dependence of the mean magnetic hyperfine field on the Co concentration was observed to be linear very similar to that of experimental values of the magnetic moment per atom in the literature. The magnetic hyperfine field and its broad distribution are discussed in a simple model with RKKY interaction. This revised version was published online in September 2006 with corrections to the Cover Date.     

“On water” ultrasound-assisted one pot efficient synthesis of functionalized 2-oxo-benzo[1,4]oxazines: First application to the synthesis of anticancer indole alkaloid,Cephalandole A

For the first time, an efficient, simple, synthetic green protocol for the one-pot synthesis of functionalized 2-oxo-benzo[1,4]oxazines 24–29 in water under ultrasound irradiation is presented. As compared to conventional methods, the present protocol avoids traditional chromatography and purification steps and furnished the target molecules in excellent yields (upto 98%) with no side products. The methodology was also demonstrated on gram scale synthesis. Moreover, functionalized 2-oxo-quinoxaline analogues 31–33, another class of bio-active heterocyclic scaffolds, were also prepared using this method. For the first time, this protocol was successfully applied in the synthesis of the anticancer indole alkaloid, Cephalandole A 35.     

LINEAR ACTIVE STRUCTURES AND MODES (Ⅱ) —DISCRETE SYSTEMS AND BEAMS

IntroductionThestudiedobjectintheclassicstructuredynamicsisthepassivestructureswhicharechangedintoactivestructurewhencontroldevicesorsmartmaterialsareintroducedintoandthecontrolfunctionisapplied .Anactivestructureisgenerallycalledactivesystem .Asforthedefinitionofactivestructure ,itistheconceptofworthydiscussion[1].Thedefinitionshouldbebecomingrigorouswiththestudyontheactivestructuraldynamics.Withincertaincategoryofactivestructuresinpaper (Ⅰ ) [2 ],someattributesaboutthemodesoflinearactivest…     

The microwave spectrum of methyl chlorodifluoroacetate: Methyl internal rotation and chlorine nuclear electric quadrupole coupling

A chirped pulse microwave spectrometer has been used to record microwave spectra of the ³⁵Cl and ³⁷Cl isotopologues of methyl chlorodifluoroacetate, CClF₂C(O)OCH₃, between 8 GHz and 16 GHz. The target compound was spectroscopically examined as it participated in a supersonic expansion of argon. Only one conformer was observed. The rotational spectra were recorded with sufficient resolution to observe (i) splittings due to the internal rotation of the methyl group, and (ii) splittings from the coupling of the chlorine quadrupolar nucleus. A total of 785 transitions have had quantum numbers assigned. Analysis of the spectra observed has produced an experimental barrier to the methyl group internal rotation, V₃, of 370(2) cm⁻¹. It is noted that this barrier is a little lower than that determined for methyl acetate [V₃ = 425 cm⁻¹, J. Sheridan, W. Bossert and A. Bauder, J. Mol. Spectrosc., 80 (1980) 1-11], and this is rationalized through a comparison of molecular structures. Lastly, all components of both the ³⁵Cl and ³⁷Cl chlorine nuclear electric quadrupolar coupling tensor have been determined.     

On the eigenvectors of the q‐Bernstein operators

In this article, both the eigenvectors and the eigenvalues of the q‐Bernstein operators have been studied. Explicit formulae are presented for the eigenvectors, whose limit behavior is determined both in the case 0 < q < 1 and in the case q > 1. Because the classical case, where q = 1, was investigated exhaustively by S. Cooper and S. Waldron back in 2000, the present article also discusses the related similarities and distinctions with the results in the classical case. Copyright © 2013 John Wiley & Sons, Ltd.