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21.
We compute the curvature of the -metric on the direct image of a family of Hermitian holomorphic vector bundles over a family of compact Kähler manifolds. As an application, we show that the -metric on the direct image of a family of ample line bundles over a family of abelian varieties and equipped with a family of canonical Hermitian metrics is always projectively flat. When the parameter space is a compact Kähler manifold, this leads to the poly-stability of the direct image with respect to any Kähler form on the parameter space.
22.
介绍速度调制分子离子光谱实验中光谱线强度对放电电流和混合气体各分量气压等实验参量的依赖关系,并测量得该光谱仪的测量极限为1.56×10-6 . 相似文献
23.
To Fu Ma 《Mathematical Methods in the Applied Sciences》2001,24(8):583-594
In this paper, we study the equation under non‐linear boundary conditions which model the vibrations of a beam clamped at x=0 and supported by a non‐linear bearing at x=L. By adding only one damping mechanism at x=L, we prove the existence of a global solution and exponential decay of the energy. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
24.
We study experimentally the jamming phenomenon of granular flow of monodisperse disks of D = 5 mm diameter in a two-dimensional hopper with opening R. The jamming probability J(d) is measured where d identical withR/D. We found that J(d) decreases from 1 to zero when d increases from 2 to 5. From observing the disk configurations of the arch in the jamming events, the jamming probability can be explained quantitatively by treating the arch as the trajectory of a restricted random walker. 相似文献
25.
26.
The fabrication of a novel sheathless interface for capillary electrophoresis–electrospray–mass spectrometry (CE–ESI–MS) is described. A programmable CO2 laser was used to ablate small channels in the walls of a polyimide capillary near the terminus. Subsequent exposure of the channel region to a cellulose acetate solution followed by drying resulted in the formation of an electrically conductive semi-permeable membrane. Application of an appropriate voltage to the reservoir resulted in the simultaneous establishment of an electrical connection for CE and ESI. Interface viability was demonstrated by conducting a CE separation of a peptide mixture, with detection accomplished via positive ion mode ESI–MS. For the peptide Val-Tyr-Val, a limit of detection of 0.1 femtomole (S/N 3) was achieved using single reaction monitoring. Attributes of the interface include structural robustness, ease of fabrication, minimal interface dead volume, and the ability to alter post-separation analyte ionization status by use of appropriate buffers in the interface reservoir. 相似文献
27.
Total internal reflection microscopy was used to directly measure the interaction potentials between a micron-sized silica sphere and a flat silica surface in the presence of a linear poly(N-isopropylacrylamide) (PNIPAM) aqueous solution. When the PNIPAM concentration was low, no discernible forces were detected. A further increase in PNIPAM concentration resulted in a long-range attraction which was likely due to a combined of the reduced electrostatic interaction between the silica particle and the flat surface after the polymer adsorption and polymer bridges formation. On the other hand, for a fixed PNIPAM concentration, the interaction potential profiles between the particle and flat surface were once again characterized by attraction as temperature was increased. This attractive force can be explained in terms of the conformational changes of PNIPAM chains at the surfaces, which subsequently affected the polymer adsorption and enhanced the segment–segment interaction among the adsorbed polymer chains. 相似文献
28.
Juliana S Luz Celso RR Ramos Márcia CT Santos Patricia P Coltri Fernando L Palhano Debora Foguel Nilson IT Zanchin Carla C Oliveira 《BMC biochemistry》2010,11(1):22
Background
The archaeal exosome is formed by a hexameric RNase PH ring and three RNA binding subunits and has been shown to bind and degrade RNA in vitro. Despite extensive studies on the eukaryotic exosome and on the proteins interacting with this complex, little information is yet available on the identification and function of archaeal exosome regulatory factors. 相似文献29.
30.
László Csaba Bencze Csaba Paizs Monica Ioana Toşa Maria Trif Florin Dan Irimie 《Tetrahedron: Asymmetry》2010,21(16):1999-2004
A highly stereoselective enzymatic kinetic resolution of novel various substituted racemic furylbenzthiazole-2-yl-ethanols and their acetates has been developed. Both processes, the enzymatic acylation of the racemic alcohols and the enzymatic methanolysis of racemic acetates yielded highly enantiomerically enriched (ee >98%) resolution product, when CaL-B was used as a biocatalyst in acetonitrile. The absolute configuration of the obtained (R)-(+)-1-(5-(4-chlorobenzo[d]thiazol-2-yl)furan-2-yl)ethanol was determined by a detailed 1H NMR study of rac- and (+)-1-(5-(4-chlorobenzo[d]thiazol-2-yl)furan-2-yl)ethanol Mosher derivatives. 相似文献