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1.
2.
Summary A stop time S in the boson Fock space over L
2()+ is a spectral measure in [0,] such that {S([0,t])} is an adapted process. Following the ideas of Hudson [6], to each stop time S a canonical shift operator U
Sis constructed in . When S({}) has the vacuum as a null vector U
Sbecomes an isometry. When S({})=0 it is shown that admits a factorisation
S]{S
where {S
is the range of U
Sand
S] is a suitable subspace of called the Fock space upto time S. This, in particular, implies the strong Markov property of quantum Brownian motion in the boson as well as fermion sense and the Dynkin-Hunt property that the classical Brownian motion begins afresh at each stop time. The stopped Weyl and fermion processes are defined and their properties studied. A composition operation is introduced in the space of stop time to make it a semigroup. Stop time integrals are introduced and their properties constitute the basic tools for the subject. 相似文献
3.
The syntheses of 7′-methoxy- and 5′,7′,6-trimethoxy-coumarino(3′,4′:3,2)coumarones (IIa and IIb) are described. 相似文献
4.
In this paper, the transport of Cu(II) in the presence of lipophilic Cu(II) organic complexes through permeation liquid membranes (PLMs) have been investigated. In natural waters, small organic compounds, which form liposoluble neutral complexes with Cu(II), are potentially toxic and bioavailable. Hence, to understand the role of liposoluble Cu(II) complexes in natural waters, four organic ligands: phthalic acid, bipyridyl, pyrocatechol and hydroxyquinoline, which form uncharged or lipophilic Cu(II) complexes, were tested. The results showed that the transport of lipophilic Cu(II) complexes through PLM depends on the lipophilicity of the complex. Applications of PLMs in natural waters are presented. 相似文献
5.
Nguyen Van Suc H. B. Desai R. Parthasarathy S. Gangadhaŕan 《Journal of Radioanalytical and Nuclear Chemistry》1992,164(5):321-325
Individual rare earth impurities in high purity La2O3 (99.9%) have been determined by NAA after pre-separation of the matrix (La). The separation is carried out on an anion exchanger (Dowex 1×8) using different mixtures of methanol/nitric acid as eluants. The rare earth elements from Dy to Lu are eluted quantitatively using a 10% 1M HNO3-90% methanol mixture, while the light rare earths from Ce to Gd are eluted quantitatively using a 10% 0.05M HNO3-90% methanol mixture. La, which is retained on the column, is eluted using 0.1M HNO3. The recoveries of the various rare earth elements have been checked using radiotracers and also by spiking the sample with known amount of elements, and the recoveries are found to be quantitative. Results obtained on a typical high purity lanthanum oxide are reported here. 相似文献
6.
N. Ramasubbu R. Parthasarathy 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):221-229
Abstract Using the Cambridge Crystallographic Data Base and computer retrieval methods, we have studied the preferred directions of approach of nucleophiles and electrophiles at divalent selenium centers. We find that electrophiles approach Se in a direction nearly normal to the selenide plane Y-Se-Z while nucleophiles approach Se nearly in the selenide plane and along the back side of Y-Se or Z-Se bonds. We also found evidence for the incipient formation of attractive electrophile-nucleophile pairing in Se…Se interactions. Other Se…Se contacts which did not fit the above pattern showed non-spherical effective shape for Se atoms. The preferred directions of approach of electrophiles and nucleophiles for Se and S are very similar and may be understood in terms of frontier orbitals. Such similarity in the shape and orbital environment of S and Se indicate to some extent how Se can play the role of S in some enzymes. 相似文献
7.
Gerd Wellenreuther Venkataraman Parthasarathy Wolfram Meyer‐Klaucke 《Journal of synchrotron radiation》2010,17(1):25-35
In biological systems, X‐ray absorption spectroscopy (XAS) can determine structural details of metal binding sites with high resolution. Here a method enabling an automated analysis of the corresponding EXAFS data is presented, utilizing in addition to least‐squares refinement the prior knowledge about structural details and important fit parameters. A metal binding motif is characterized by the type of donor atoms and their bond lengths. These fit results are compared by bond valance sum analysis and target distances with established structures of metal binding sites. Other parameters such as the Debye–Waller factor and shift of the Fermi energy provide further insights into the quality of a fit. The introduction of mathematical criteria, their combination and calibration allows an automated analysis of XAS data as demonstrated for a number of examples. This presents a starting point for future applications to all kinds of systems studied by XAS and allows the algorithm to be transferred to data analysis in other fields. 相似文献
8.
Parthasarathy Saravanan Suparna Gupta Arpita DattaGupta Sonia Gupta Vinod K. Singh 《合成通讯》2013,43(15):2695-2699
The cleavage of α-hydroxy tert-butyldimethylsilyl ether to diol takes place efficiently with LAH. It has been proposed that the reaction proceeds via intramolecular hydride transfer from the alkoxy aluminium hydride. In order to substantiate this, reduction of TBDMS ether with LAH in a variety of substrates was studied. 相似文献
9.
Narayanan Parthasarathy David DeShazer Sharon J. Peacock Vanaporn Wuthiekanun Marilyn J. England Sarah L. Norris 《Journal of carbohydrate chemistry》2013,32(1):32-40
Burkholderia pseudomallei is the causative agent of melioidosis, a bacterial infection endemic in tropical regions including southeast Asia and northern Australia. B. pseudomallei contains structurally unique polysaccharides (capsular polysaccharide and O?antigen saccharides of lipopolysaccharide). A polysaccharide microarray platform was developed by immobilizing these polysaccharides onto glass slides. Employing this microarray, we were able to demonstrate the presence of antibodies to these polysaccharide antigens in the sera of melioidosis patients, but not in serum from nonmelioidosis human subjects. The advantages of this polysaccharide microarray technology over the conventional tests for the serodiagnosis of melioidosis are discussed. 相似文献
10.
Jayachandran Jayakumar Kanniyappan Parthasarathy Yi‐Hsiang Chen Tai‐Hua Lee Shih‐Ching Chuang Chien‐Hong Cheng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(37):10047-10050
A new method for the synthesis of highly substituted naphthyridine‐based polyheteroaromatic compounds in high yields proceeds through rhodium(III)‐catalyzed multiple C H bond cleavage and C C and C N bond formation in a one‐pot process. Such highly substituted polyheteroaromatic compounds have attracted much attention because of their unique π‐conjugation, which make them suitable materials for organic semiconductors and luminescent materials. Furthermore, a possible mechanism, which involves multiple chelation‐assisted ortho C H activation, alkyne insertion, and reductive elimination, is proposed for this transformation. 相似文献