排序方式: 共有43条查询结果,搜索用时 14 毫秒
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Ali Elriati Karin Achilles Jutta Loose Hans-Hartwig Otto 《Monatshefte für Chemie / Chemical Monthly》2007,76(5):627-634
4-Phenylazetidine-2-one was transformed into 4-phenylazetidine-1-alkanoic acids, which were reacted in the presence of diphenylphosphoroazidate
with amino acid esters and dipeptide esters yielding β-lactam peptides with different spacers between the lactam ring and
the peptide moiety. All structures were established by elementary analyses, HPLC, optical rotation, and spectroscopic data
and all new compounds were tested as inhibitors of PPE using standard procedures. Four compounds exhibited a weak activity compared with the standard inhibitor trifluoroacetyl-l-val-l-tyr-l-val. 相似文献
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Ericsson M Achilles D Barreiro JT Branning D Peters NA Kwiat PG 《Physical review letters》2005,94(5):050401
Geometric phase may enable inherently fault-tolerant quantum computation. However, due to potential decoherence effects, it is important to understand how such phases arise for mixed input states. We report the first experiment to measure mixed-state geometric phases in optics, using a Mach-Zehnder interferometer, and polarization mixed states that are produced in two different ways: decohering pure states with birefringent elements; and producing a nonmaximally entangled state of two photons and tracing over one of them, a form of remote state preparation. 相似文献
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Fiber-assisted detection with photon number resolution 总被引:1,自引:0,他引:1
We report the development of a photon-number-resolving detector based on a fiber-optical setup and a pair of standard avalanche photodiodes. The detector is capable of resolving individual photon numbers and operates on the well-known principle by which a single-mode input state is split into a large number (eight) of output modes. We reconstruct the photon statistics of weak coherent input light from experimental data and show that there is a high probability of inferring the input photon number from a measurement of the number of detection events on a single run. 相似文献
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J. Unterzaucher A. Stoll E. Wiedemann A. Friedrich F. Blumer I. Marek W. R. Kirner H. A. Taylor H. E. Achilles S. Abe R. Hara H. Sinozaki D. T. Gibson Th H. Caulfield P. L. Kirk K. Dod und E. C. Kendall 《Fresenius' Journal of Analytical Chemistry》1937,110(7-8):291-298
Ohne Zusammenfassung 相似文献
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Vairis Shtrauss 《ournal of non Newtonian Fluid Mechanics》2010,165(9-10):453-465
The article is devoted for the determination of the relaxation and retardation spectrum (RRS) from monotonic time- and frequency-domain material functions by the inverse functional filters executing discrete convolution algorithms for geometrically spaced data. It is shown that the problem of RRS determination from a wide variety of material functions leads to the three inverse filtering tasks on a logarithmic time or frequency scale with the three specific frequency responses concerning: (i) the time-domain functions, (ii) the real parts and (iii) the imaginary parts of the frequency-domain functions, and three algorithms (having the versions with even and odd number of coefficients) are to be applied to: (i) time-domain compliance and modulus functions, (ii) their derivatives, and (iii) frequency-domain functions. It is demonstrated that ill-posedness of an inverse filter manifests as large sampling-rate-dependent noise amplification coefficients. A novel regularization strategy allowing to ensure the desired noise immunity is proposed based on choosing sampling rate for geometrically spaced data. The performance of the algorithms is investigated. Optimal sampling rates are disclosed for specific material functions. The frequency range of 2–3 decades is established to be optimal for the recovery of a single RRS point estimate ensuring maximum accuracy with reasonable noise immunity. Practical algorithms are proposed for recovering RRS from the real and imaginary parts of frequency-domain functions. Some known non-parametric methods are compared with the suggested functional filters. 相似文献
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Metastable states of homogeneous 2D and 3D Ising models are studied under free boundary conditions. The states are defined in terms of weak and strict local minima of the total interaction energy. The morphology of these minima is characterized locally and globally on square and cubic grids. Furthermore, in the 2D case, transition from any spin configuration that is not a strict minimum to a strict minimum is possible via non-energy-increasing single flips. 相似文献
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