排序方式: 共有20条查询结果,搜索用时 46 毫秒
1.
A. A. Veber A. Lyashedko E. Sholokhov A. Trikshev A. Kurkov Y. Pyrkov A. E. Veber V. Seregin V. Tsvetkov 《Applied physics. B, Lasers and optics》2011,105(3):613-617
A novel technique is represented that allows one to measure vibrations from a distant object with micron and sub-micron amplitudes
in real time. 相似文献
2.
R Bonfiglio RC King TV Olah K Merkle 《Rapid communications in mass spectrometry : RCM》1999,13(12):1175-1185
A post-column infusion system was developed in order to analyze suppression of electrospray ionization (ESI) tandem mass spectrometry response in the presence of endogenous plasma interferences. By enabling direct detection of these interfering components, this experimental system was used to analyze the ability of several common extraction procedures to remove endogenous plasma components that cause changes in the ESI response of model drug substances. Methyl-t-butyl ether (MTBE) liquid-liquid, Oasis and Empore solid-phase, and acetonitrile (ACN) protein precipitation sample preparation methods were tested using the post-column infusion system. In all cases, ACN protein precipitation samples showed the greatest amount of ESI response suppression while liquid-liquid extracts demonstrated the least. In addition, the three test compounds, phenacetin, caffeine, and a representative Merck compound, demonstrated that ESI response suppression is compound dependent. Suppression was greatest with caffeine, the most polar analyte, and the smallest for the Merck compound, the least polar analyte. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
3.
We investigate the evolution of entanglement in multiple-quantum (MQ) NMR experiments in crystals with pairs of close nuclear
1/2-spins. The initial thermodynamic equilibrium state of the system in a strong external magnetic field evolves under the
nonsecular part of the dipolar Hamiltonian. As a result, MQ coherences of the zeroth and plus/minus second orders appear.
A simple condition for the emergence of entanglement is obtained. We show that the measure of the spin-pair entanglement—concurrence—coincides
qualitatively with the intensity of MQ coherences of the plus/minus second order and, hence, the entanglement can be studied
with MQ NMR methods. We introduce an entanglement witness using MQ NMR coherences of the plus/minus second order.
The text was submitted by the authors in English. 相似文献
4.
Pyrkov TV Priestle JP Jacoby E Efremov RG 《SAR and QSAR in environmental research》2008,19(1-2):91-99
Molecular docking is a powerful computational method that has been widely used in many biomolecular studies to predict geometry of a protein-ligand complex. However, while its conformational search algorithms are usually able to generate correct conformation of a ligand in the binding site, the scoring methods often fail to discriminate it among many false variants. We propose to treat this problem by applying more precise ligand-specific scoring filters to re-rank docking solutions. In this way specific features of interactions between protein and different types of compounds can be implicitly taken into account. New scoring functions were constructed including hydrogen bonds, hydrophobic and hydrophilic complementarity terms. These scoring functions also discriminate ligands by the size of the molecule, the total hydrophobicity, and the number of peptide bonds for peptide ligands. Weighting coefficients of the scoring functions were adjusted using a training set of 60 protein-ligand complexes. The proposed method was then tested on the results of docking obtained for an additional 70 complexes. In both cases the success rate was 5-8% better compared to the standard functions implemented in popular docking software. 相似文献
5.
王建功 《纯粹数学与应用数学》1993,9(1):79-86
T.Sheil-Small[1]讨论了阶梯函数的Fourier级数。本文对[1]中所涉及到一些阶梯函数的性质进行了详细讨论,并给出了详细证明。 相似文献
6.
Pyrkov TV Kosinsky YA Arseniev AS Priestle JP Jacoby E Efremov RG 《Journal of chemical information and modeling》2007,47(3):1171-1181
Most standard molecular docking algorithms take into account only ligand flexibility, while numerous studies demonstrate that receptor flexibility may be also important. While some efficient methods have been proposed to take into account local flexibility of protein side chains, the influence of large-scale domain motions on the docking results still represents a challenge for computational methods. In this work we compared the results of ATP docking to different models of Ca-ATPase: crystallographic apo- and holo-forms of the enzyme as well as "flexible" target models generated via molecular dynamics (MD) simulations in water. MD simulations were performed for two different apo-forms and one holo-form of Ca2+-ATPase and reveal large-scale domain motions of type "closure", which is consistent with experimental structures. Docking to a set of MD-conformers yielded correct solutions with ATP bound in both domains regardless of the starting Ca2+-ATPase structure. Also, special attention was paid to proper ranking of docking solutions and some particular features of different scoring functions and their applicability for the model of "flexible" receptor. Particularly, the results of docking ATP were ranked by a scoring criterion specially designed to estimate ATP-protein interactions. This criterion includes stacking and hydrophobic interactions characteristic of ATP-protein complexes. The performance of this ligand-specific scoring function was considerably better than that of a standard scoring function used in the docking algorithm. 相似文献
7.
Spectral and luminescence properties of gadolinium gallium garnet epitaxial films doped with terbium
N. V. Vasil’eva V. V. Randoshkin V. N. Kolobanov E. B. Kryukova V. V. Mikhaĭlin N. N. Petrovnin V. G. Plotnichenko Yu. N. Pyrkov D. A. Spasskiĭ N. N. Sysoev 《Physics of the Solid State》2007,49(3):478-483
Gadolinium gallium garnet single-crystal films containing terbium are grown through liquid-phase epitaxy from a supercooled solution melt in the PbO-B2O3 system. The optical absorption spectra in the wavelength range 0.2–10.0 μm and the luminescence spectra excited by synchrotron radiation with energies in the range 3.5–30.0 eV are investigated at temperatures of 10 and 300 K. It is revealed that the optical absorption spectra contain an absorption band with the maximum at a wavelength λ ≈0.260 μm, which corresponds to the spin-allowed electric dipole transition between the electronic configurations 4f 8(7 F 6) → 4f 7(8 S)5d of the Tb3+ ions. The narrow low-intensity absorption bands attributed to the 4f → 4f transitions from the 7 F 6 ground level to the 7 F 0–5 multiplet levels of the Tb3+ ions are observed in the wavelength range 1.7–10.0 μm. In the luminescence spectra measured at a temperature of 10 K, the highest intensity is observed for a band with the maximum at a wavelength λ ≈ 0.544 μm, which is associated with the 5 D 4 → 7 F 5 radiative transition in the Tb3+ ion. 相似文献
8.
S. I. Doronin A. N. Pyrkov E. B. Fel’dman 《Journal of Experimental and Theoretical Physics》2007,105(5):953-961
We investigate entanglement of spin pairs in alternating open spin chains (s = 1/2) with spin-spin interactions (SSI) in the thermodynamic equilibrium state in an external magnetic field. The reduced density matrix of an arbitrarily chosen spin pair was calculated. The entanglement of a spin pair was evaluated with the Wootters criterion. The temperature at which the entangled state arises in the chosen pair was determined. Entanglement (concurrence) is shown to oscillate as a function of the position of a spin pair in the chain. The results demonstrate the dependence of the entanglement in arbitrarily chosen pairs of neighboring spins on the temperature, the position of the spin pair in the chain, chain length, and the ratio between the SSI constants. Qualitative explanation of these dependences is offered. The role of the terminal spins in the generation of entanglement is explained. 相似文献
9.
林苏榕 《数学物理学报(A辑)》1998,(Z1)
该文研究极限方程在部分边界上为退缩椭圆型(椭圆-抛物)的一类六阶椭圆型方程混合边值问题的奇摄动,在适当的假设下,应用改进了的多重尺度法,求得其解包括边界层和套层在内除了半圆域的两个角点外,在整个半圆域中有任意阶的一致有效的渐近展开式. 相似文献
10.
Dianov EM Plotnichenko VG Koltashev VV Pyrkov YN Ky NH Limberger HG Salathe RP 《Optics letters》1997,22(23):1754-1756
Raman spectra of germanosilicate core fibers before and after UV irradiation were investigated. Significant changes of the Raman spectra after irradiation indicate transformation of the glass structure. A possible interpretation of the observed changes is proposed. 相似文献