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排序方式: 共有266条查询结果,搜索用时 15 毫秒
1.
P. Seelig A. Dax S. Faber M. Gerlach G. Huber T. Kühl D. Marx P. Merz W. Quint F. Schmitt H. Winter M. Würtz 《Hyperfine Interactions》1998,114(1-4):135-139
The investigation of the 1s HFS provides a good possibility for testing QED effects in a combination of a strong electric
and magnetic field. Here, we report about the laserspectroscopic measurements of the ground state hyperfine splitting in 207Pb81+. To handle this M1-transition in the infrared optical regime with its long lifetime, we developed a new detection technique
using a bunched ion beam. For the observation of fluorescence light, a new mirror system is adapted to the emission characteristics
from an ion beam at relativistic velocities.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
Erik J. Faber Dr. Wouter Sparreboom Wilrike Groeneveld Louis C. P. M. de Smet Dr. Johan Bomer Wouter Olthuis Dr. Han Zuilhof Dr. Ernst J. R. Sudhölter Prof. Piet Bergveld Prof. Albert van den Berg Prof. 《Chemphyschem》2007,8(1):101-112
The electrochemical behavior of Si--C linked organic monolayers is studied in electrolyte-insulator-Si devices, under conditions normally encountered in potentiometric biosensors, to gain fundamental knowledge on the behavior of such Si electrodes under practical conditions. This is done via titration experiments, Mott-Schottky data analysis, and data fitting using a site-binding model. The results are compared with those of native SiO(2) layers and native SiO(2) layers modified with hexamethyldisilazane. All samples display pH sensitivity. The number of Si--OH groups on the alkylated samples is calculated to be less than 0.7 % of that of a pure SiO(2) insulator, which still causes a pH sensitivity of approximately 25 mV per pH unit in the pH range: 4-7. The alkylated samples hardly suffer from response changes during up- and down-going titrations, which indicates that very little oxide is additionally formed during the measurements. The pK(a) values of all samples with monolayers (4.0-4.4) are lower than that of native SiO(2) (6.0). The long-term drift (of approximately 1 mV h(-1)) is moderate. The results indicate that biosensors composed of alkylated Si substrates are feasible if a cross-sensitivity towards pH in the sensor signal is taken into account. 相似文献
3.
Nonracemic sec-alcohols of opposite absolute configuration were obtained either by asymmetric reduction of the corresponding ketone using 2-propanol as hydrogen donor or by enantioselective oxidation through kinetic resolution of the rac-alcohol using acetone as hydrogen acceptor employing whole lyophilized cells of Rhodococcus ruber DSM 44541. The microbial oxidation/reduction system exhibits not only excellent stereo- and enantioselectivity but also a broad substrate spectrum. Due to the exceptional tolerance of the biocatalyst toward elevated concentrations of organic materials (solvents, substrates and cosubstrates), the process is highly efficient. The simple preparation of the biocatalyst and its ease of handling turns this system into a versatile tool for organic synthesis. 相似文献
4.
5.
A new approach is developed for estimating the limit of detection in second-order bilinear calibration with the generalized rank annihilation method (GRAM). The proposed estimator is based on recently derived expressions for prediction variance and bias. It follows the latest IUPAC recommendations in the sense that it concisely accounts for the probabilities of committing both types I and II errors, i.e. false positive and false negative declarations, respectively. The estimator has been extensively validated with simulated data, yielding promising results. 相似文献
6.
7.
I. A. Smirnov T. S. Orlova B. I. Smirnov D. W. Wlosewicz H. Misiorek A. Jezowski T. E. Wilkes K. T. Faber 《Physics of the Solid State》2009,51(11):2264-2268
This paper reports on measurements in the 80–300-K temperature interval of the heat capacity at constant pressure C
p
(T) of high-porosity amorphous white pine carbon preforms (biocarbon) prepared by pyrolysis (carbonization) at T
carb = 1000 and 2400°C in an argon flow. The dependences C
p
(T) for biocarbon/copper composites based on the carbon preforms obtained have also been determined. It is shown that the mixture
rule holds for the composites, i.e., that C
p
(T) of the composite is a sum of the heat capacities of the constituent materials taken in the corresponding ratios. Phonon
mean free paths for the white pine carbon preforms prepared at T
carb = 1000 and 2400°C have been calculated and used to estimate the size of the nanocrystallites contributing to formation of
the carbon frameworks of these preforms. 相似文献
8.
9.
Using the statistical model, an estimate is obtained for the critical angular momentum when the rotational band ofγ-rays ends up in reactions with heavy ions. A model of classical non-quantized rotation is proposed for angular momenta exceeding the critical value. Estimates for the intensity ofγ-radiation and the descend time along the yrast-line proceeding the quantal rotation are given. 相似文献
10.
A.?N.?IvanovEmail author M.?Cargnelli M.?Faber H.?Fuhrmann V.?A.?Ivanova J.?Marton N.?I.?Troitskaya J.?Zmeskal 《The European Physical Journal A - Hadrons and Nuclei》2005,25(3):329-338
We argue that due to isospin and U-spin invariance of strong low-energy interactions the S-wave scattering lengths a
0
0 and a
1
0 of ˉN scattering with isospin I = 0 and I = 1 satisfy the low-energy theorem a
0
0 +3a
1
0 = 0 valid to leading order in chiral expansion. In the model of strong low-energy ˉN interactions at threshold (Eur. Phys. J. A 21, 11 (2004)) we revisit the contribution of the Σ(1750) resonance, which does not saturate the low-energy theorem a
0
0 +3a
1
0 = 0, and replace it by the baryon background with properties of an SU(3) octet. We calculate the S-wave scattering amplitudes of K-N and K-d scattering at threshold. We calculate the energy level displacements of the ground states of kaonic hydrogen and deuterium.
The result obtained for kaonic hydrogen agrees well with recent experimental data by the DEAR Collaboration. We analyse the
cross-sections for elastic and inelastic K-p scattering for laboratory momenta 70MeV/c < p
K < 150MeV/c of the incident K--meson. The theoretical results agree with the available experimental data within two standard deviations. 相似文献