Thermal resistivity and hydrodynamics of the degenerate electron fluid in antimony

Detecting hydrodynamic fingerprints in the flow of electrons in solids constitutes a dynamic field of investigation in contemporary condensed matter physics. Most attention has been focused on the regime near the degeneracy temperature when the thermal velocity can present a spatially modulated profile. Here, we report on the observation of a hydrodynamic feature in the flow of quasi-ballistic degenerate electrons in bulk antimony. By scrutinizing the temperature dependence of thermal and electric resistivities, we detect a size-dependent departure from the Wiedemann-Franz law, unexpected in the momentum-relaxing picture of transport. This observation finds a natural explanation in the hydrodynamic picture, where upon warming, momentum-conserving collisions reduce quadratically in temperature both viscosity and thermal diffusivity. This effect has been established theoretically and experimentally in normal-state liquid 3He. The comparison of electrons in antimony and fermions in 3He paves the way to a quantification of momentum-conserving fermion-fermion collision rate in different Fermi liquids.

Study on Relation between Hydrodynamic Feature Size of HPAM and Pore Size of Reservoir Rock in Daqing Oilfield

The flow mechanism of the injected fluid was studied by the constant pressure core displacement experiments in the paper. It is assumed under condition of the constant pressure gradient in deep formation based on the characteristic of pressure gradient distribution between the injection and production wells and the mobility of different polymer systems in deep reservoir. Moreover, the flow rate of steady stream was quantitatively analyzed and the critical flow pressure gradient of different injection parameters polymer solutions in different permeability cores was measured. The result showed that polymer hydrodynamic feature size increases with the increasing molecular weight. If the concentration of polymer solutions overlaps beyond critical concentration, then molecular chains entanglement will be occur and cause the augment of its hydrodynamic feature size. The polymer hydrodynamic feature size decreased as the salinity of the dilution water increased. When the median radius of the core pore and throat was 5–10 times of the polymer system hydrodynamic feature size, the polymer solution had a better compatibility with the microscopic pore structure of the reservoir. The estimation of polymer solutions mobility in the porous media can be used to guide the polymer displacement plan and select the optimum injection parameters.

Research on Numerical Simulations of Pollutant of Sewage

To study the ocean environmental problem, the article analyses and predicts the hydrodynamic feature of study area on the basis of Ecom model. After simulation of the contributed concentration field, the paper assesses the influence of the cyanide in discharge of sewage on the marine water quality nearby. Research shows that the results reflected the rules of transportation and diffusion of pollutants in the tidal water area bitterly.

Research of the Artificial Island Construction Impact on Marine Deposit Dynamic Environment

The article analyses and predicts the hydrodynamic feature of Tang Shan bay on the basis of Ecomsed model, thus the calculation accuracy is improved. And then it predicts erosion-deposition characteristics of the study sea area.The paper assesses the influence of the artificial island construction in aspects of hydrodynamic and erosion-deposition environment. Research shows that the sea area in the north of the artificial island is deposition area because of sand excavation and the water inside is slightly deposit.

Effect on Hydrodynamic and Erosion-Deposition Characteristics after Sea Wall Backout

The article analyses and predicts the hydrodynamic feature of Zhifu bay on the basis of Ecomsed model, thus the calculation accuracy is improved. And then it predicts erosion-deposition characteristics of the study sea area. The paper assesses the influence of the sea wall backout in aspects of hydrodynamic and erosion-deposition environment. Simulating results show that the velocity of flow will increase after the sea wall backout and the ability of water exchange will be improved gradually. Research shows that the deposition-dominating areas are located at the north and east of study area, while the southeast side area is dominated by erosion. The accretion tendency will weaken in south of study area together with the accretion thickness 1cm/a annually, while the accretion thickness is 5cm/a in southeast of study area.

Surface Modification of Titanium by High Intensity Ultra-Short Nd:YAG Laser

The effects of an Nd:YAG laser interaction with titanium target using laser radiation at wavelengths 1.064 or 0.532 μm (40 picoseconds pulse duration) were studied. Modification of target surfaces at laser energy densities of 2.4 and 10.3 J/cm2 (λ1 laser= 1.064 μm) and 1.1 J/cm2 (λ2 laser= 0.532 μm) are reported in this article. Qualitatively, the titanium surface modification can be summarized as follows: (i) ablation of the titanium surface in the central zone of the irradiated area for both laser wavelengths; (ii) appearance of a hydrodynamic feature like resolidified droplets of the material (λ1 laser= 1.064 μm), as well as formation of the wave-like microstructures (λ2 laser= 0.532 μm); and (iii) appearance of plasma, in front of the target, with both laser wavelengths.