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排序方式: 共有390条查询结果,搜索用时 46 毫秒
21.
22.
Fine Substituent Effects in Sandwich Complexes: A Threshold Ionization Study of Monosubstituted Chromium Bisarene Compounds
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Prof. Dr. Sergey Yu. Ketkov Dr. Gennady V. Markin Sheng Y. Tzeng Prof. Dr. Wen B. Tzeng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(14):4690-4694
Mass‐analyzed threshold ionization spectra of jet‐cooled [(η6‐PhMe)(η6‐PhH)Cr] and [(η6‐Ph2)(η6‐PhH)Cr] reveal with unprecedented accuracy the effects of methyl and phenyl groups on the electronic structure of bis(η6‐benzene)chromium. These “pure” substituent effects allow quantitative experimental determination of the ionization energy changes caused by the mutual substituent influence in bisarene systems. Two types of such influence have been revealed for the first time in bis(η6‐toluene)chromium. 相似文献
23.
Makoto Maejima Gennady Samorodnitsky 《Annals of the Institute of Statistical Mathematics》1999,51(3):449-462
We study the extent to which the property of semistability of a random vector in
d
is determined by semistability of its marginals, and the place of semistable laws within the family of type G and sub-stable laws. Similarities and differences between stable and semistable laws are discussed. 相似文献
24.
Karataev P Araki S Hamatsu R Hayano H Muto T Naumenko G Potylitsyn A Terunuma N Urakawa J 《Physical review letters》2004,93(24):244802
An experiment on the investigation of optical diffraction radiation (ODR) from a slit target as a possible tool for noninvasive electron beam-size diagnostics has been performed at the KEK accelerator test facility. The experimental setup has been installed at the diagnostics section of the extraction line. We have performed the first incoherent ODR observation from a slit target. The measured angular distributions are in reasonable agreement with the theoretical expectation. The beam-size effect onto the ODR angular pattern has been observed. Moreover, the sensitivity to the beam size as small as 14 microm has been achieved. 相似文献
25.
Engineering the electromagnetic properties of periodic nanostructures using electrostatic resonances
Electromagnetic properties of periodic two-dimensional subwavelength structures consisting of closely packed inclusions of materials with negative dielectric permittivity epsilon in a dielectric host with positive epsilon(h) can be engineered using the concept of multiple electrostatic resonances. Fully electromagnetic solutions of Maxwell's equations reveal multiple wave propagation bands, with the wavelengths much longer than the nanostructure period. Some of these bands are described using the quasistatic theory of the effective dielectric permittivity epsilon(qs). Those bands exhibit multiple cutoffs and resonances which are found to be related to each other through a duality condition. An additional propagation band characterized by a negative magnetic permeability is found. Imaging with subwavelength resolution in that band is demonstrated. 相似文献
26.
Cholinesterase sensors based on screen-printed electrodes for detection of organophosphorus and carbamic pesticides 总被引:4,自引:0,他引:4
Ivanov A Evtugyn G Budnikov H Ricci F Moscone D Palleschi G 《Analytical and bioanalytical chemistry》2003,377(4):624-631
Cholinesterase sensors based on screen-printed electrodes modified with polyaniline, 7,7,8,8-tetracyanoquinodimethane (TCNQ), and Prussian blue have been developed and tested for detection of anticholinesterase pesticides in aqueous solution and in spiked grape juice. The influence of enzyme source and detection mode on biosensor performance was explored. It was shown that modification of the electrodes results in significant improvement of their analytical characteristics for pesticide determination. Thus, the slopes of the calibration curves obtained with modified electrodes were increased twofold and the detection limits of the pesticides were reduced by factors of 1.6 to 1.8 in comparison with the use of unmodified transducers. The biosensors developed make it possible to detect down to 2×10–8 mol L–1 chloropyrifos-methyl, 5×10–8 mol L–1 coumaphos, and 8×10–9 mol L–1 carbofuran in aqueous solution and grape juice. The optimal conditions for grape juice pretreatment were determined to diminish interference from the sample matrix.Abbreviations ChE Cholinesterase - TCNQ 7,7,8,8-Tetracyanoquinodimethane - ChO Choline oxidase - AChE Acetylcholinesterase - BChE Butyrylcholinesterase - BSA Bovine serum albumin - 2-PAM 2-Pyridine aldoxime methiodide 相似文献
27.
In [2] E. Dobrowolski and K.S. Williams considered a problem of obtaining estimates for the sum
n=a+1
a+N
f(n),for a certain class of functions f. One specific application of their result is a new method for estimating character sums. In particular, they obtain a form of the Pólya-Vinogradov inequality with the constant 1/(2 log 2). In this note we improve their estimates and obtain, in particular, a form of the Pólya-Vinogradov inequality with the constant 1/(3 log 3). A nice feature of our estimate is that it is obtained by a very simple argument. 相似文献
28.
Egor V. Verbitskiy Svetlana A. Baskakova Natal’ya A. Gerasimova Natal’ya P. Evstigneeva Natal’ya V. Zil’berberg Nikolay V. Kungurov Marionella A. Kravchenko Gennady L. Rusinov Oleg N. Chupakhina Valery N. Charushin 《Mendeleev Communications》2018,28(4):393-395
A facile synthetic approach to 5-arylamino-4-(5-nitrofuran- 2-yl)pyrimidines by the Buchwald–Hartwig cross-coupling with various anilines has been developed. All synthesized compounds demonstrated a significant level of in vitro antibacterial activity against Neisseria gonorrhoeae, Streptococcus pyogene and Staphylococcus aureus, including their drug-resistant strains, which is much higher than that of the commercial drug Spectinomycin. 相似文献
29.
A fluid queue with ON periods arriving according to a Poisson process and having a long-tailed distribution has long range
dependence. As a result, its performance deteriorates. The extent of this performance deterioration depends on a quantity
determined by the average values of the system parameters. In the case when the the performance deterioration is the most
extreme, we quantify it by studying the time until the amount of work in the system causes an overflow of a large buffer.
This turns out to be strongly related to the tail behavior of the increase in the buffer content during a busy period of the
M/G/∞ queue feeding the buffer. A large deviation approach provides a powerful method of studying such tail behavior.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
30.
Anastasia S. Kozlenko Nadezhda I. Makarova Ilya V. Ozhogin Artem D. Pugachev Maria B. Lukyanova Irina A. Rostovtseva Gennady S. Borodkin Natalia V. Stankevich Anatoly V. Metelitsa Boris S. Lukyanov 《Mendeleev Communications》2021,31(3):403-406
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