Nonlinear renormalization-group analysis applied to the hydrodynamic light scattering spectrum of4He belowT λ

We calculate the observable critical temperature dependence of the transport coefficients entering the hydrodynamic form of the dynamic structure factor of⁴He belowT . Application of our recently introduced nonlinear renormalization-group analysis yields quantitative agreement with previous light scattering experiments in the hydrodynamic region. This resolves a long-standing problem in the critical dynamics below the superfluid transition of⁴He.Supported in part by the Fonds zur Förderung der wissenschaftlichen Forschung     

Structural and Kinetic Aspects of Blood Plasma Protein Adsorption on the Surface of Hydrophobic Polymers

Abstract

Due to the wide use of polymers in medicine, researchers are required to solve a very important problem–to understand the interaction between materials of nonphysiological origin and the surrounding biological liquids, and tissues, particularly blood.     

高聚合度Ⅱ-型聚磷酸铵的合成

用聚合反应-热处理两段工艺合成了高聚合度的聚磷酸铵（APP）阻燃材料,其结构经XRD,粒度及平均聚合度表征。优化反应条件为：磷酸氢二铵1mol,n（磷酸氢二铵）：n（五氧化二磷）：n（脲）：1．0：1．0：0．3．干燥氨气氛下于290℃反应30min,再经250℃-280℃后处理100min-110min。APP的平均聚合度大于150,粒度小于50μm。     

The correction-to-scaling exponent in dilute systems

The leading correction-to-scaling exponent ω for the three-dimensional (3D) dilute Ising model is calculated in the framework of the field theoretic renormalization group approach. Both in the minimal subtraction scheme and in the massive field theory (resummed four-loop expansion) excellent agreement with recent Monte Carlo calculations (H. G. Ballesteros et al., Phys. Rev. B 58, 2740 (1998)) is achieved. The expression of ω as a series in a expansion up to O(ɛ²) does not permit a reliable estimate for d=3. Pis’ma Zh. éksp. Teor. Fiz. 69, No. 10, 698–702 (25 May 1999) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Frequency-dependent shear viscosity, sound velocity, and sound attenuation near the critical point in liquids. III. The shear viscosity

We compare theoretical results for the shear viscosity calculated in one-loop order within the field-theoretical method of the renormalization-group theory with experiments. Our expressions describe the nonasymptotic crossover in both temperature and density, and allow us to consider effects of finite gravitation and finite frequency at which the experiments are performed. In doing so we treat the critical exponent x(eta) of the shear viscosity as an independent parameter, keeping the one-loop value of the Kawasaki amplitude fixed. Within our model we also consider the temperature and density dependence of the thermal diffusion including gravitational effects.     

A direct preparation of fluorinated imides

N-Fluorosulfuryltrifluoroacetimide and N-chlorosulfuryltrifluoroacetimide have been prepared in high yield by a one-step reaction of trifluorothiolacetic acid with the corresponding fluoro- and chlorosulfuryl isocyanates. The trifluoroacetimides are easily purified by vacuum sublimation from the crude product mixture.     

Nonasymptotic critical dynamics of the asymmetric-spin model in two-loop order

The crossover behaviour in the dynamics near the Lambda transition of⁴He is analyzed on the basis of the complete renormalization-group flow equations for the asymmetric-spin model (F) in two-loop order. Our results confirm the conclusions and refine the results obtained from an earlier analysis based on the symmetric model (E) and invalidate part of a recent analysis treating model F in an unsystematic approximation. Excellent agreement is found with measurements of second-sound damping over four decades in relative temperature. Closer toT our analysis predicts a further increase of the effective amplitudeR ^eff of the thermal conductivity.Supported in part by the Fonds zur Förderung der wissenschaftlichen Forschung