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991.
992.
O'Hare B Grutzeck MW Kim SH Asay DB Benesi AJ 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,195(1):85-102
Deuterium NMR relaxation experiments, low temperature deuterium NMR lineshape analysis, and FTIR spectra are consistent with a new model for solid state jump dynamics of water in (2)H(2)O-synthesized kanemite and (2)H(2)O-hydrated Na(+)-Zeolite A. Exchange occurs between two populations of water: one in which water molecules are directly coordinated to sodium ions and experience C(2) symmetry jumps of their OH bonds, and a population of interstitial water molecules outside the sodium ion coordination sphere that experience tetrahedral jumps of their OH bonds. For both samples the C(2) jump rate is much faster than the tetrahedral jump rate. (2)H NMR relaxation experiments match well with the fast exchange regime of the model over a wide range of temperatures, including room temperature and above. For hydrated Zeolite A, the kinetic activation parameters for the tetrahedral and C(2) symmetry jumps are Delta H tet++=+17 kJ/mol, Delta S tet++=-109 J/(mol K), Delta H C2++=+19 kJ/mol, and Delta S C2++=-20 J/(mol K). For kanemite, Delta H tet++ =+23 kJ/mol, Delta S tet++=-69 J/(mol K), Delta H C2++ =+23 kJ/mol, and Delta S C2++ =-11 J/(mol K). 相似文献
993.
Im HJ Ito T Kim HD Kimura S Lee KE Hong JB Kwon YS Yasui A Yamagami H 《Physical review letters》2008,100(17):176402
Ce 4d-4f resonant angle-resolved photoemission spectroscopy was carried out to study the electronic structure of strongly correlated Ce 4f electrons in a quasi-two-dimensional nonmagnetic heavy-fermion system CeCoGe1.2Si0.8. For the first time, dispersive coherent peaks of an f state crossing the Fermi level, the so-called Kondo resonance, are directly observed together with the hybridized conduction band. Moreover, the experimental band dispersion is quantitatively in good agreement with a simple hybridization-band picture based on the periodic Anderson model. The obtained physical quantities, i.e., coherent temperature, Kondo temperature, and mass enhancement, are comparable to the results of thermodynamic measurements. These results manifest an itinerant nature of Ce 4f electrons in heavy-fermion systems and clarify their microscopic hybridization mechanism. 相似文献
994.
It has been known for over six decades that the dissolution of minute amounts of high molecular weight polymers in wall-bounded turbulent flows results in a dramatic reduction in turbulent skin friction by up to 70%. First principles simulations of turbulent flow of model polymer solutions can predict the drag reduction (DR) phenomenon. However, the essential dynamical interactions between the coherent structures present in turbulent flows and polymer conformation field that lead to DR are poorly understood. We examine this connection via dynamical simulations that track the evolution of hairpin vortices, i.e., counter-rotating pairs of quasistreamwise vortices whose nonlinear autogeneration and growth, decay and breakup are centrally important to turbulence stress production. The results show that the autogeneration of new vortices is suppressed by the polymer stresses, thereby decreasing the turbulent drag. 相似文献
995.
D.G. Park D.W. Kim C.S. Angani V.P. Timofeev Y.M. Cheong 《Journal of magnetism and magnetic materials》2008
The magnetic properties of stainless steel have been investigated using a radio frequency (RF) high-temperature superconductivity (HTS) SQUID (Superconducting QUantum Interference Device)-based susceptometer. The nuclear grade 304 stainless steel is nonmagnetic at a normal condition but it changes to a partially ferromagnetic state associated with martensitic transformation under a plastic deformation. The magnetic moment of the 304 stainless steels was increased with an increasing cold work rate, and decreased with an increasing annealing temperature. The change of mechanical properties such as yield strength and ultimate tensile strength (UTS) are also analyzed in terms of deformation-induced martensitic transformation. 相似文献
996.
D. Bimberg C. Meuer M. Lmmlin S. Liebich J. Kim A. Kovsh I. Krestnikov G. Eisenstein 《中国光学快报(英文版)》2008,6(10)
The dynamics of nonlinear processes in quantum dot (QD) semiconductor optical amplifiers (SOAs) are investigated. Using small-signal measurements, the suitabilities of cross-gain and cross-phase modulation as well as four wave mixing (FWM) for wavelength conversion are examined. The cross-gain modulation is found to be suitable for wavelength conversion up to a frequency of 40 GHz. 相似文献
997.
Peter Gregorčič Rok Petkovšek Janez Možina Griša Močnik 《Applied Physics A: Materials Science & Processing》2008,93(4):901-905
We present an optodynamic measurement of a laser-induced cavitation bubble and its oscillations based on a scanning technique
using a laser beam-deflection probe. The deflection of the beam was detected with a fast quadrant photodiode which was built
into the optical probe. The applied experimental setup enabled us to carry out one- or two-dimensional scanning of the cavitation
bubble, automatic control of the experiment, data acquisition and data processing. Shadow photography was used as a comparative
method during the experiments. 相似文献
998.
In this paper, we propose a method that controls the depth of the three-dimensional (3D) object existing over the depth-of-focus in integral imaging. The depth control method is performed only in a computer by synthesizing the intermediate sub-images between original sub-images obtained by transforming the captured elemental images. In the reconstruction process, we can obtain reconstructed 3D images with the better image quality within depth-of-focus than that reconstructed over the depth-of-focus. To demonstrate the feasibility of our method, optical and computational experiments are carried out and its results are presented. 相似文献
999.
Hee-Man Yang Chan Woo Park Kune Woo Lee Byung-Sik Lee Ilgook Kim In-Ho Yoon 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(3):955-962
A polyvinyl alcohol (PVA)-borate hydrogel-based strippable surface decontaminant containing an ammonium salt and Prussian blue (PB) was developed for the removal of 137Cs from various surfaces. This surface decontaminant can be easily prepared by the simple mixing of commercially available materials, such as PVA, borax, NH4Cl and PB, in water, and the decontaminant can be peeled off surfaces due to its high elastic property after surface decontamination. The hydrogel displayed an effective removal performance for Cs from painted cement, aluminum, stainless steel, and cement surfaces and a potential for reusability. Therefore, the PB/PVA-borate hydrogel has good potential as a new surface decontaminant. 相似文献
1000.
Tae-Wook Kim Seul-Kee Kim Sungkyun Park Kang Hyun Park Jae-Myung Lee 《Journal of Radioanalytical and Nuclear Chemistry》2018,317(1):145-159
The present study investigated thermal and mechanical characteristics of irradiated polyurethane foams (PUFs) according to the irradiation does under various temperature conditions, including low/cryogenic temperatures. Fourier transform infrared analysis was performed to obtain information on the PUF molecular structure. In addition, Macro- and microstructural investigations were carried out to determine the relationship between thermal and mechanical characteristics and irradiation dose. The test results were quantitatively presented, and it was found that the irradiated PUF has potential for application in industrial structures. 相似文献