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31.
We have measured the elastic properties of a glass at audiofrequencies (0.2–1.5 kHz) in the temperature interval 0.01 to 10 K. In the superducting glassy metal Cu60Zr40 (Tc=0.31 K) both the sound velocity and attenuation are similar to that of an insulating glass below 0.05 K. Above that temperature (Tc>T>0.05 K) the relaxation process is mainly governed by electrons which are thermally excited above the BCS gap. Above the superconducting transition we observed new features in the sound velocity which were not observed in high frequency measurements. 相似文献
32.
33.
We derive trace formulas for a pair of self-adjoint operators and H under the assumption that is in a Schatten class. This extends the trace formulas of [8], where V alone is assumed to be in a Schatten class. Our trace formulas apply, in particular, in the setting of differential operators and are based on Taylor-like approximations of operator functions. This significantly improves non-Taylor based trace formulas of [10]. 相似文献
34.
The goal of this article is to extend some results of Popescu (Probab. Theory Relat. Fields 144:179, 2009) in several directions. We establish the limiting spectral distribution (LSD) for r-diagonal matrices under reduced moment conditions compared to those required by Popescu. We also deal with the joint convergence of several sequences of such matrices. In particular, we show that there is a large class of such matrices where the joint limit is not free while the marginals are semicircular. We also consider matrices of the form $X_{n}X_{n}^{T}$ where X n is a sequence of nonsymmetric r-diagonal random matrices and establish their limiting spectral distribution. 相似文献
35.
Structural Chemistry - The N-methyl-D-aspartate (NMDA) is the family of glutamate receptor, which is involved in controlling synaptic plasticity and memory function; but overactivation of this... 相似文献
36.
G. Benz H. Lüers P. Bohrisch M. Tortelli R. Ruggeri W. Otte E. Kröger W. Lühr H. Schmalfuß H. Werner R. Strohecker J. Großfeld A. Beckel H. Thaler K. Täufel K. Richter H. Damm E. Ruppol H. A. A. Aitken R. Delaby Yvonne Breugnot S. F. Juschkewitsch N. M. Ssokolow P. Arup J. T. Minster 《Analytical and bioanalytical chemistry》1933,94(7-8):286-295
37.
Biswas R Das AR Pradhan T Touraud D Kunz W Mahiuddin S 《The journal of physical chemistry. B》2008,112(21):6620-6628
Catanionic microemulsions formed by dodecyltrimethylammonium bromide (DTAB), sodium dodecyl sulfate (SDS), n-hexanol, dodecane, and citrate buffer have been characterized by using dynamic light scattering (DLS) and spectroscopic studies. While the DLS measurements provide information about the hydrodynamic diameters of the microemulsion droplets formed upon variation of the constituents, steady-state and time-resolved fluorescence emission experiments probe the polarity and the dynamics of the trapped solvent pool inside of the microemulsion droplets of nanometer dimension. In addition, time-resolved fluorescence anisotropy shows the rigidity of the confined solvent pool as well as the coupling between the motion of a solute and those of the solvent molecules. The results obtained from the DLS and those from the steady-state and time-resolved fluorescence emission studies have been found to correlate well with the superactivity of horseradish peroxidase enzyme in the catanionic microemulsions. Subsequently, the time-zero estimate for the dynamic Stokes shift in these microemulsions reveals that approximately 50% of the total solvent dynamical response is missed due to the limited time resolution employed in our experiments. The amplitude of the missing portion is similar to what has been observed recently for nanoscopic water by Fayer and co-workers (Piletic, I. R.; Tan, H.-S.; Fayer, M. D. J. Phys. Chem. B 2005, 109, 21273). 相似文献
38.
BOSE Arup 《中国科学A辑(英文版)》2009,(6)
We study the asymptotic distribution of the L1 regression estimator under general condi-tions with matrix norming and possibly non i.i.d.errors.We then introduce an appropriate bootstrap procedure to estimate the distribution of this estimator and study its asymptotic properties.It is shown that this bootstrap is consistent under suitable conditions and in other situations the bootstrap limit is a random distribution. 相似文献
39.
Stachowiak JC Yue M Castelino K Chakraborty A Majumdar A 《Langmuir : the ACS journal of surfaces and colloids》2006,22(1):263-268
When biomolecular reactions occur on one surface of a microcantilever beam, changes in intermolecular forces create surface stresses that bend the cantilever. While this phenomenon has been exploited to create label-free biosensors and biomolecular actuators, the mechanisms through which chemical free energy is transduced to mechanical work in such hybrid systems are not fully understood. To gain insight into these mechanisms, we use DNA hybridization as a model reaction system. We first show that the surface grafting density of single-stranded probe DNA (sspDNA) on a surface is strongly correlated to its radius of gyration in solution, which in turn depends on its persistence length and the DNA chain length. Since the persistence length depends on ionic strength, the grafting density of sspDNA can be controlled by changing a solution's ionic strength. The surface stresses produced by the reaction of complementary single-stranded target DNA (sstDNA) to sspDNA depend on the length of DNA, the grafting density, and the hybridization efficiency. We, however, observe a remarkable trend: regardless of the length and grafting density of sspDNA, the surface stress follows an exponential scaling relation with the density of hybridized sspDNA. 相似文献
40.